A systematic review of the survival and complication rates of implant-supported fixed dental prostheses (FDPs) after a mean observation period of at least 5 years

Effect of hydroxyapatite nanoparticles coating of titanium surface on biofilm adhesion: An in vitro study

AIM

To evaluate the adhesion of mono and duospecies biofilm on a commercially available dental implant surface coated with hydroxyapatite nanoparticles (nanoHA).

MATERIAL AND METHODS

Titanium discs were divided into two groups: double acid-etched (AE) and AE coated with nanoHA (NanoHA). Surface characteristics evaluated were morphology, topography, and wettability. Mono and duospecies biofilms of Streptococcus sanguinis (S. sanguinis) and Candida albicans (C. albicans) were formed. Discs were exposed to fetal bovine serum (FBS) to form the pellicle. Biofilm was growth in RPMI1640 medium with 10% FBS and 10% BHI medium for 6 h. Microbial viability was evaluated using colony-forming unit and metabolic activity by a colorimetric assay of the tetrazolium salt XTT. Biofilm architecture and organization were evaluated by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM).

RESULTS

AE surface had more pores, while NanoHA had even nanoHA crystals distribution. Roughness was similar (AE: 0.59 ± 0.07 µm, NanoHA: 0.69 ± 0.18 µm), but wettability was different (AE: Θw= 81.79 ± 8.55°, NanoHA: Θw= 53.26 ± 11.86°; P = 0.01). NanoHA had lower S. sanguinis viability in monospecies biofilm (P = 0.007). Metabolic activity was similar among all biofilms. In SEM both surfaces on C. albicans biofilm show a similar distribution of hyphae in mono and duospecies biofilms. AE surface has more S. sanguinis than the NanoHA surface in the duospecies biofilm. CLSM showed a large proportion of live cells in all groups.

CONCLUSIONS

The nanoHA surface reduced the adhesion of S. sanguinis biofilm but did not alter the adhesion of C. albicans or the biofilm formed by both species.

Cost-Effectiveness Analysis of Implant-Supported Single Crown and Tooth-Supported Fixed Dental Prostheses in Türkiye

OBJECTIVES

The most cost-effective option for replacing lost teeth is not evident because there is a dearth of evidence-based information on implant-supported single crowns versus tooth-supported fixed dental prostheses. This study conducted the analysis of cost-effectiveness of implant-supported single crown and tooth-supported fixed dental prostheses from a social perspective in Türkiye.

METHODS

Costs were calculated in the analysis from a social perspective for 2021. Costs and quality-adjusted prosthesis year (QAPY) values were computed over a 20-year period in the study using the Markov model. The computed values were discounted by 5%. The results are presented as the incremental cost-effectiveness ratio. To assess the impact of uncertainty on cost-effectiveness analyses, a tornado diagram and Monte Carlo simulations were created.

RESULTS

Throughout the 20-year time horizon, tooth-supported fixed dental prostheses cost $985.58 cumulatively, whereas implant-supported single crown cost $2161.64 (US $1 = 9.22 ₺ as of 15 October 2021). The calculated incremental cost-effectiveness ratio is 1.333 per QAPY. Compared with the implant-supported single crown tooth-supported fixed dental prostheses, it offers a QAPY of 0.882 over a 20-year period, while costing an additional $1176.06.

CONCLUSIONS

These results suggest that the implant-supported single crown provided higher QAPY value but was costlier. When the research's findings are compared with the literature, it becomes clear that Türkiye has lower dental care expenses than most other nations.

Effect of different impression coping and scan body designs on the accuracy of conventional versus digital implant impressions: An in vitro study

OBJECTIVES

This in vitro study compared the accuracy of conventional versus digital impression techniques for angulated and straight implants using two different impression coping and scan body designs.

METHODS

Two implant systems were used: Straumann and Dentegris. Two implants were placed for each system, straight and angulated at 15 degrees mesiodistally. Conventional impressions were made using the splinted open-tray technique using narrow impression coping (NIC) and wide impression coping (WIC). The stone casts produced from the conventional impression were digitized with a lab scanner (3Shape D2000). Digital impressions were made using four intraoral scanners (IOS): 3Shape Trios 3, Medit i700, Cerec Omnicam, and Emerald Planmeca using short scanbodies (SSB) and long scanbodies (LSB). The scanning was repeated ten times to generate the Standard Tessellation Language (STL) files. The distance and angle deviations between impression copings and scanbodies were measured in reference to the master model.

RESULTS

The trueness and precision of SSB and WIC were significantly better than LSB and NIC (p<0.001). The range trueness of the platform deviation was better with SSB (37.1 to 51.9) than LSB (89.6 to 127.9 μm) and for WIC than NIC in conventional impressions (58.2 and 75.1 μm, respectively). The trueness of the angle deviation of digital scans with SSB (0.11 to 0.25 degrees) was significantly better than scans with LSB (0.31 to 0.57 degrees) and for WIC than NIC (0.21 and 0.52 degrees, respectively). The precision of the platform deviation of digital scans with SSB (12.4 to 34.5 μm) was higher than other scans and conventional impressions (42.9 to 71.4 μm). The precision of the angle deviation of Medit i700 and Trios 3 with SSB (0.17 and 0.20 degrees, respectively) was higher than other scans with SSB and conventional impressions (0.54 to 1.63 degrees).

CONCLUSIONS

Digital scans with SSB were more accurate than conventional splinted open-tray impressions. The type of impression coping and scanbody significantly affected the impression accuracy.

CLINICAL SIGNIFICANCE

The use of a short scanbody can increase the accuracy of digital impressions, and wide impression coping can increase the accuracy of conventional impressions, resulting in improved clinical outcomes.

Maintenance protocols for implant-supported dental prostheses: A scoping review

STATEMENT OF THE PROBLEM

Biological complications of implant-supported prostheses remain a concern. Therefore, standardizing hygiene protocols to promote their maintenance is important.

PURPOSE

The purpose of this scoping review was to identify available hygiene guidance for home care procedures, as well as periodicity and protocols for the professional maintenance of implant-supported prostheses.

MATERIAL AND METHODS

This study was based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, and the study protocol was made available at: https://osf.io/5jdeh/. The search was last performed in the PubMed database on March 15, 2022 and was undertaken by 2 independent researchers. Clinical studies and reviews that evaluated home care and maintenance protocols for dental implant-supported prostheses (fixed or removable), without language restriction or year of publication, were included. A descriptive analysis was performed considering study characteristics (study design, restorative assembly, maintenance strategies, eligibility criteria, number of included studies, quality/level of evidence, and main findings).

RESULTS

The initial search yielded 3138 studies, of which 18 were included for descriptive analysis (6 critical reviews, 4 clinical trials, 3 systematic reviews, 2 guideline reports, 2 retrospective studies, and 1 transversal study). The main instrument recommended for home care was the use of a conventional toothbrush associated with triclosan-containing toothpaste in addition to interproximal aids (brushes or floss) for all types of restorations. The use of irrigation instruments was also frequently considered. For professional maintenance, almost all studies reported a positive effect of regular recalls every 3 months during the first year, followed by less regular recalls according to the motivation of the patient and home care efficacy. At each recall, the professional should evaluate the patient history, oral tissues, implant, abutments, and restorations, as well as perform professional cleaning of the prostheses with appropriate instruments so that the implants and abutments may be preserved.

CONCLUSIONS

Establishing an adequate hygiene protocol is indispensable for implant-supported restorations. To do so, the professional must guide and support the patient's home care by taking into account the patient's motivation and efficacy during the hygiene procedures. Also, for professional maintenance, the periodicity of recalls should be constant and include an evaluation of the condition of the restoration and adjacent tissues, followed by professional cleaning of prostheses, implants, and abutments, in addition to new instructions to improve patient home care.

Effect of scan body designs and internal conical angles on the 3-dimensional accuracy of implant digital scans

STATEMENT OF PROBLEM

Axial displacement is inevitable when connecting scan bodies to implants for digital scans using intraoral scanners, and axial displacement may reduce implant position accuracy in digital casts. However, studies assessing scan body type and accuracy are lacking.

PURPOSE

The purpose of this in vitro study was to assess the linear and angular displacements of implants in digital casts using 2 scan body types with or without a vertical stop to minimize the axial displacement and 2 internal conical connection implants (ICCIs) with different internal conical angles.

MATERIAL AND METHODS

Two identical reference casts were fabricated from epoxy resin by duplicating a partially edentulous mandibular dentiform. Each cast received 3 implants in the left first premolar, first molar, and second molar regions. One cast received an ICCI with a 7-degree internal conical angle (7-degree ICCI), and the other received an ICCI with an 11-degree internal conical angle (11-degree ICCI). A 10-mm polyetheretherketone (PEEK) cube was attached to the buccal area of the mandibular second premolar of each reference cast. A vertical stop was used in the experimental scan bodies to minimize the axial displacement, and conventional scan bodies were hand tightened to the implants in the reference casts. An intraoral scanner was used to fabricate 4 digital cast groups (2 implant types and 2 scan body types; each group had 10 casts). A coordinate measuring machine and digital inspection software program were used to measure the implant platform centroids (x, y, z) and projection angles (θXY, θYZ, θZX) of implant long axes in the reference and digital casts, respectively. One-way analysis of variance (ANOVA) and linear mixed model both with Tukey post hoc and 2-way ANOVA tests were performed to assess the significance of linear and angular displacements between groups (α=.05).

RESULTS

Significant differences were noted in all linear displacement variables among the 4 digital cast groups, except for Δx in the left first premolar implant. For the 7-degree ICCI, the linear displacement was statistically similar in the experimental and conventional scan bodies. However, for the 11-degree ICCIs, the experimental scan body group resulted in significantly smaller Δy, Δz, and Δd (Δd2=Δx2+Δy2+Δz2) than the conventional scan body group (P<.05). Overall, the 11-degree ICCIs demonstrated a significantly greater linear displacement than the 7-degree ICCI, regardless of the scan body type (P<.05). Significant differences between the test groups were observed for 10 of the 12 angular displacement variables (P<.05).

CONCLUSIONS

The 11-degree ICCIs demonstrated significantly greater linear displacements in Δy, Δz, and Δr than the 7-degree ICCIs. The experimental scan bodies with a vertical stop demonstrated significantly smaller linear displacements in the 11-degree ICCIs.

Rehabilitation of mandibular resected patients using fixed immediately loaded corticobasal implant -supported prostheses. A case series

INTRODUCTION AND IMPORTANCE

Aliments such as congenital conditions, pathological, and iatrogenic circumstances may result in mandibular defects that can severely disturb the patients' oral health, functions (mastication, speech), aesthetics, and quality of life and present a rehabilitating challenge.

CASE PRESENTATION

we present a multidisciplinary treatment approach for three cases presented with mandibular resection as a consequence of cystic, benign, and malignant tumour eradication that were rehabilitated with immediately loaded fixed corticobasal implant-supported prostheses and a follow-up period of 5,5 and 4 years. The reported cases present with excellent implant survival, along with healthy peri-implant tissues, stable prostheses, enhanced speech, chewing ability, aesthetics, superior patient satisfaction, and improved overall self-esteem.

CLINICAL DISCUSSION

A multidisciplinary oral and maxillofacial team is mandatory for the successful rehabilitation of patients with mandibular resection and to restore soft and hard tissue loss. The reported treatment modality offers the patient immediate fixed implant-supported prostheses omitting the need for a bone grafting procedure, with optimum peri-implant tissue health, excellent biomechanical and prosthetic results, and significant improvement in function and satisfaction.

CONCLUSION

Corticobasal fixed implant-supported prostheses can be a reliable treatment modality for mandibular resection, resulting in notable enhancements in the patients' oral health, appearance, mastication, speech, and self-esteem.

Clinical Performance of 170 Frictional Morse Taper Implants: 2 Years Follow-Up

This study evaluated the clinical survival rates of 170 Morse taper implants through clinical and mechanical parameters in different therapeutic approaches such as single crowns, fixed partial prostheses, and fixed full-arch prostheses. Patients referred to the Center on Education and Research on Dental Implants from May 2017 to July 2018 with the indication for dental implant therapy, aged >18 years, without periodontal disease, recent evidence of inflammatory activity or other oral disorders, current pregnancy, uncontrolled diabetes mellitus or heavy smoking habit were included in this study. After 12 weeks of healing since the implants were placed in the mandible and after 16 weeks following implants placed in the maxilla, patients returned to the Center for prosthetic rehabilitation. After implant therapy, all patients underwent periodical, clinical, and prosthetic examinations every 6 months. Prosthetic restorations involved 109 fixed reconstructions in function. Few prosthetic complications were reported (6.55%). Twenty implants were rehabilitated with cemented prostheses; from those, 1 crown suffered a loss in retention/decementation. Of the 148 implants rehabilitated with screwed-retained prostheses, 6.76% suffered prosthetic screw loosening. The cumulative implant survival rate was 98.2%. When peri-implant tissue health was evaluated, the keratinized mucosa band appeared related to peri-implant tissue stability. Thus, Morse taper implants represented a successful procedure for implant rehabilitation, with a high cumulative implant survival rate, low prevalence of biological and prosthetic complications, and good stability of peri-implant tissues over the assessed period.

Fracture Resistance of a Bone-Level Two-Piece Zirconia Oral Implant System-The Influence of Artificial Loading and Hydrothermal Aging

Preclinical and clinical research on two-piece zirconia implants are warranted. Therefore, we evaluated the in vitro fracture resistance of such a zirconia oral implant system. The present study comprised 32 two-piece zirconia implants and abutments attached to the implants using a titanium (n = 16) or a zirconia abutment screw (n = 16). Both groups were subdivided (n = 8): group T-0 comprised implants with a titanium abutment screw and no artificial loading; group T-HL was the titanium screw group exposed to hydro-thermomechanical loading in a chewing simulator; group Z-0 was the zirconia abutment screw group with no artificial loading; and group Z-HL comprised the zirconia screw group with hydro-thermomechanical loading. Groups T-HL and Z-HL were loaded with 98 N and aged in 85 °C hot water for 107 chewing cycles. All samples were loaded to fracture. Kruskal-Wallis tests were executed to assess the loading/bending moment group differences. The significance level was established at a probability of 0.05. During the artificial loading, there was a single occurrence of an implant fracture. The mean fracture resistances measured in a universal testing machine were 749 N for group T-0, 828 N for group Z-0, 652 N for group T-HL, and 826 N for group Z-HL. The corresponding bending moments were as follows: group T-0, 411 Ncm; group Z-0, 452 Ncm; group T-HL, 356 Ncm; and group Z-HL, 456 Ncm. There were no statistically significant differences found between the experimental groups. Therefore, the conclusion was that loading and aging did not diminish the fracture resistance of the evaluated implant system.

Comparison of Four Different Dental Implant Removal Techniques in Terms of the Weight and Volume of Bone Loss

PURPOSE

Several approaches have been suggested for implant removal. However, further research is necessary to review data regarding the amount of bone removed and the duration of removal time for different procedures. This study evaluates and compares various implant removal techniques.  Materials and methods: A polyurethane block was scanned to create an implant surgical guide. Afterward, implant-guided surgery was performed on 60 simulated bone blocks. The implants were then separated into four groups and removed utilizing the counter-torque ratchet, trephine drills, burs, and piezosurgery.

RESULTS

For the weight of bone loss, there were significant differences in the median between the counter-torque ratchet technique (CTRT) and trephine (p < 0.01), CTRT and bur (p < 0.01), trephine and piezo (p < 0.01), and bur and piezo (p = 0.04). All groups, except CTRT and the piezo group, demonstrated a statistically significant difference (p < 0.01) in the procedure durations. Regarding the volume of bone loss, a statistically significant difference (p < 0.01) was found between each group.  Conclusions: CTRT showed the least amount of bone loss. On the other hand, the trephine technique was demonstrated to be the fastest. It is essential to consider the limitations and risks when choosing the approach for implant removal.

Enhancing oral function: A case report on mandibular overdenture utilization with custom-made subperiosteal implant

Subperiosteal implants, previously set aside because of complications, are now emerging again as effective treatments for severe mandibular atrophy, aided by recent improvements in digital dentistry. Traditional dentures in such cases often face challenges with support and retention, necessitating complex regenerative procedures. This paper presents a case report of a 54-year-old male patient with significant mandibular atrophy who received a custom-made subperiosteal implant, showcasing promising results. The implant was precisely designed utilizing computed tomography (CT) scans, a 3D-printed model, the selective laser melting (SLM) technique, and constructed with biocompatible Ti6Al4V material. This innovative approach offered a practical solution, resulting in high patient satisfaction and no complications over a year of use.

Short and Extra Short Dental Implants in Osseous Microvascular Free Flaps: A Retrospective Case Series

There is limited information regarding implant and prosthetic survival after osseous microvascular free flap (OMFF). This case series aims to describe the placement of short and extra short implants in osseous microvascular free flaps to support prostheses, and present an up to 40-month retrospective follow-up. Short and extra short dental implants were placed in six fibula free flaps (FFF) and in two microvascular deep circumflex iliac artery (DCIA) flaps. In total, 27 short and extra short dental implants have been placed into two different types of free flaps. Kaplan-Meyer (K-M) survival analyses were performed to evaluate the survival and success outcomes of implants and prostheses. Out of the eight patients reconstructed with free flap, five were rehabilitated with prostheses, one patient has a temporary prosthesis, and two patients are in the process of prosthetic rehabilitation. Twenty-seven implants were followed up for up to 40 months, and K-M analyses showed 100% implant survival probability (95% confidence interval: 100%), while the implant success probability was 91.0% (95% confidence interval: 68.6-97.7%). Short and extra short dental implants placed in OMFF presented high survival and success rates in a retrospective case series after up to 40 months.

Influence of Titanium Surface Residual Stresses on Osteoblastic Response and Bacteria Colonization

Grit basting is the most common process applied to titanium dental implants to give them a roughness that favors bone colonization. There are numerous studies on the influence of roughness on osseointegration, but the influence of the compressive residual stress associated with this treatment on biological behavior has not been determined. For this purpose, four types of surfaces have been studied using 60 titanium discs: smooth, smooth with residual stress, rough without stress, and rough with residual stress. Roughness was studied by optic interferometry; wettability and surface energy (polar and dispersive components) by contact angle equipment using three solvents; and residual stresses by Bragg-Bentano X-ray diffraction. The adhesion and alkaline phosphatase (ALP) levels on the different surfaces were studied using Saos-2 osteoblastic cultures. The bacterial strains Streptococcus sanguinis and Lactobacillus salivarius were cultured on different surfaces, determining the adhesion. The results showed that residual stresses lead to increased hydrophilicity on the surfaces, as well as an increase in surface energy, especially on the polar component. From the culture results, higher adhesion and higher ALP levels were observed in the discs with residual stresses when compared between smooth and roughened discs. It was also found that roughness was the property that mostly influenced osteoblasts' response. Bacteria colonize rough surfaces better than smooth surfaces, but no changes are observed due to residual surface tension.

Interproximal contact loss between implant restorations and adjacent natural teeth: A systematic review and meta-analysis

PURPOSE

This systematic review was conducted to evaluate the prevalence of interproximal contact loss (ICL) between implant restorations and adjacent teeth in relation to age, gender, follow-up time, and arch location.

METHODS

This study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and was registered in the Open Science Framework (OSF). The formulated population, intervention, comparison, outcome (PICO) question was "What is the prevalence of the ICL between implant restoration and adjacent teeth?" The search strategy used four main electronic databases and an additional manual search was performed until February 2023. Clinical studies that evaluated the prevalence of interproximal open contact between implant restorations and adjacent teeth were included. A qualitative analysis for clinical studies was used to assess the risk of bias. In addition, a single-arm meta-analysis of proportion was performed to evaluate the percentage of mesial versus distal open contact and total ICL between implant restoration and adjacent teeth.

RESULTS

Fifteen studies published between 2014 and 2023 met the eligibility criteria. Seven studies presented ICL rates higher than 20%. All studies evaluated ICL in posterior regions (molar, premolar area). Five studies had an ICL rate lower than 50% and three studies had an ICL rate higher than 50%. One study assessed the interproximal contact at three months post-restoration insertion, four studies assessed the interproximal contact at 1-year follow-up and nine studies evaluated the interproximal contact over 2 years of follow-up. Mesial and distal ICL rates were 44.2% (95% CI: 30.6% to 58.6%) and 27.5% (95% CI: 10.5% to 55.0%), respectively. The heterogeneity between studies was high (I2 (95% CI) = 87.8% (75.9% to 93.8%).

CONCLUSION

Based on the results of the included studies, the prevalence of ICL was high, occurring more frequently at the mesial contact. There were no significant differences in relation to age, gender, and arch location.

Repositioning accuracy of the implant- and abutment-level prosthetic components used in conventional and digital workflows

OBJECTIVES

To evaluate the repositioning accuracy of the implant- and abutment-level impression components (impression abutments and implant scan bodies) and implant abutments (with and without anti-rotational hex index); also, to estimate the tightening torque influence on the positional stability of abutments.

METHODS

Seven types of prosthetic components (n = 7) [impression pick-up copings (PC), implant scan bodies (ISB), non‑hex and hex titanium base implant abutments (TB H and TB NH), multi-unit impression copings (MU PC), multi-unit implant scan bodies (MU ISB), and multi-unit caps (MU C) (Medentika GmbH)] were tested. For repositioning accuracy tests a coordinate measuring machine (CMM) was used. During assembly 15 Ncm torque for all components was applied. After measurement, only hex and non‑hex abutments were torqued to 25 Ncm and their coordinates were again recorded to assess torque influence. The procedure was repeated 7 times for each component. Linear and 3D deviations, angulation to the vertical axis, and axial rotation were calculated. The Kruskal-Wallis test was used to compare the measurements between the groups. A post-hoc test (Mann-Whitney U test) was used for pairwise comparison to determine the influence of the torque (α=0.05).

RESULTS

Implant- and abutment-level components used for digital scans showed different positional discrepancies compared to ones used for conventional impressions and ranged from 10 to 37 µm. Hex abutments demonstrated statistically significantly lower 3D deviations (4.4 ± 7.1 µm) compared to non‑hex abutments (8.7 ± 6.1 µm). Torque influence was significantly lower for hex abutments than for non‑hex abutments.

CONCLUSIONS

Repositioning inaccuracies were found in all implant- and abutment-level impression components (impression abutments and implant scan bodies) and all abutments (with and without anti-rotational hex index) tested. Final tightening of the components could cause further positional discrepancies.

CLINICAL SIGNIFICANCE

The misfit of the prosthetic components used in conventional and digital workflows stays in the clinically acceptable range. Even when multiple connections and disconnections on the track of the laboratory preparation is needed, it should not have a negative influence for single teeth reconstructions. However, in the complex cases with multiple implants, repetitive repositioning of the prosthetic components may lead to the accumulation of vertical, horizontal and rotational errors leading to the clinical problems with the passive fit of the final framework.

Evaluation and assessment of the survival of tooth implant supported prosthesis in tooth and implant supported rehabilitation cases with metal frameworks

INTRODUCTION

Over the years, implant therapy has been a commonly used treatment option for individuals who are partially or totally edentulous, with a long-term success rate of over 90%. With significant advancements in biomaterials and technology, implant dentistry can now conduct prosthetic rehabilitations in the majority of patients catering to all types of needs. However, in order to meet the demands of a patient base that is always growing, new trends in implantology are emerging in recent years that are focused on minimally invasive surgery and financial sustainability. In certain clinical scenarios, connecting teeth and implants to support fixed partial prosthesis (FPPs) may be a predictable and workable course of treatment.

MATERIALS AND METHODS

22 patients were selected for this study who had tooth and implant supported prosthesis placed as a final restoration. Out of these 22 patients; 12 were male and 10 were female patients. Implants were placed following proper protocol and if grafting procedures were required they were carried out. A second stage surgical procedure was carried out and delayed loading protocols were followed. The statistical analysis was done using the IBM SPSS 24.0, Chicago, USA. The survival of the implants and teeth were measured by the Kaplan Meier survival scale. Bone loss was assessed at baseline(upon loading), 12 months and 24 months.

RESULTS

The implant survival rate was measured at 6 months, 12 months, 18 months and 24 months. At 24 months, one implant showed failure, so the survival rate of the implants were 95.4%. Bone loss of 1 mm was seen around one implant at 12 months. Bone loss of 1 and 2 mm was present around two implants and one implant respectively at 24 months.

CONCLUSION

From the results of this study, we can conclude that tooth implant supported prosthesis show very good survival when used in rehabilitation cases.

Clinical outcomes of 3-5 years follow-up of immediate implant placement in posterior teeth: a prospective study

BACKGROUND

Immediate implant placement in posterior teeth has become popular in recent years. However, only a few studies focused on evaluating the long-term success of immediate implant placement.

PURPOSE

To analyze the clinical outcomes of immediate implant placement in the posterior region with conventional loading with 3-5 years follow-up following the International Congress of Oral Implantologists (ICOI) Pisa Consensus Conference.

METHOD

The study was done in 25 bone-level implants (Straumann® SLActive® bone level tapered implant, Straumann®, Basel, Switzerland) in 19 patients who underwent immediate implant placement in a posterior tooth with conventional loading with 3-5 years follow-up. The overall success and survival of these placements were evaluated following the International Congress of Oral Implantologists (ICOI) Pisa Consensus Conference using chart records, clinical examination, radiographic evaluation, and outcomes measurement. Patient satisfaction was evaluated by using a numeric rating scale. The biological and technical status, modified Pink Esthetic Score (mPES), complications, and marginal bone change were also evaluated. The analysis was done using SPSS version 21 (SPSS Inc., Chicago, IL, USA). The data were analyzed using a paired samples t-test.

RESULTS

It was found that 24 out of the 25 (96%) dental implants survived for an average of 57 ± 8.07 months. All of the 24 surviving dental implants were considered an operational success. The average mPES was 9.75 ± 0.44. The major prosthetic complications seen were: (1) proximal contact loss (41.67%), (2) loosening of the screw (8.33%), and (3) cement debonding (4.17%).

CONCLUSIONS

Immediate implant placement in a posterior tooth with conventional loading yields a predictable result with some complications. The most prominent complications were proximal contact loss, followed by loosening of the screw and cement debonding. The implant survival rate was 96% at a mean time follow-up of 4 years and 9 months.

Screw-retained ceramic-veneered/monolithic zirconia partial implant-supported fixed dental prostheses: A 5 to 10-year retrospective study on survival and complications

PURPOSE

To assess the clinical performance of screw-retained, ceramic-veneered, monolithic zirconia partial implant-supported fixed dental prostheses (ISFDP) over 5-10 years and to evaluate implant- and prosthesis-related factors influencing treatment failure and complications.

MATERIALS AND METHODS

Partially edentulous patients treated with screw-retained all-ceramic ISFDPs with 2-4 prosthetic units with a documented follow-up of ≥5 years after implant loading were included in this retrospective study. The outcomes analyzed included implant/prosthesis failure and biological/technical complications. Possible risk factors were identified using the mixed effects Cox regression analysis.

RESULTS

A screened sample of 171 participants with 208 prostheses (95% of the restorations were splinted crowns without a pontic) supported by 451 dental implants were enrolled in this study. The mean follow-up duration after prosthesis delivery was 82.4 ±17.2 months. By the end of the follow-up period, 431 (95.57%) of the 451 implants remained functional at the implant level. At the prosthesis level, 185 (88.94%) of the 208 partial ISFDPs remained functional. Biological complications were observed in 67 implants (14.86%), and technical complications were observed in 62 ISFDPs (29.81%). Analysis revealed only emergence profiles (over-contoured) as a significant risk factor for implant failure (P<0.001) and biological complications (P<0.001). Full-coverage ceramic-veneered zirconia prostheses had a significantly greater chance of chipping (P<0.001) compared with buccal-ceramic-veneered or monolithic zirconia prostheses.

CONCLUSIONS

Screw-retained ceramic-veneered, monolithic partial ISFDPs have a favorable long-term survival rate. Over-contoured emergence profile is a significant risk factor associated with implant failure and biological complications. Buccal-ceramic-veneered and monolithic zirconia partial ISFDPs lower the initial prevalence of chipping compared with a full-coverage veneered design.

Bacterial Flora in Screw-Fixed Superstructures with Different Sealing Materials: A Comparative Clinical Trial

A screw-fixed superstructure is predominantly selected for implant prostheses because of the concern regarding developing peri-implantitis, although its infection route remains unclear. Focusing on microleakage from access holes, the present study clinically investigated the bacterial flora in access holes with different sealing materials. We examined 38 sites in 19 patients with two adjacent screw-fixed superstructures. Composite resin was used in the control group, and zinc-containing glass ionomer cement was used in the test group. Bacteria were collected from the access holes 28 days after superstructure placement and were subjected to DNA hybridization analysis. The same patient comparisons of the bacterial counts showed a significant decrease in 14 bacterial species for the red, yellow, and purple complexes in the test group (p < 0.05). In addition, the same patient comparisons of the bacterial ratios showed a significant decrease in six bacterial species for the orange, green, yellow, and purple complexes in the test group (p < 0.05). Furthermore, the same patient comparisons of the implant positivity rates showed a significant decrease in the six bacterial species for the orange, yellow, and purple complexes in the test group. The results of this study indicate that zinc-containing glass ionomer cement is effective as a sealing material for access holes.

Patient-reported outcomes following dental implant rehabilitation according to reason for missing teeth: A survey from a Norwegian population 8 years following treatment

AIM

The aim of this study was to assess patient-reported outcomes (PROs) 8 years after dental implant rehabilitation in a sample with tooth loss due to periodontitis (TLP) and a sample with missing teeth for other reasons (MTOR).

MATERIALS AND METHODS

The Norwegian National Insurance Scheme registry of subsidized dental implant therapy was searched, and patients (n = 3083) rehabilitated with dental implants in 2014 were mailed a questionnaire. PROs were described by relative frequencies, and the TLP and MTOR subsamples were compared using chi-square test. Multiple linear regression analyses were used to investigate variables potentially predicting PROs.

RESULTS

Of the respondents (n = 1299), more than 90% were partly or fully satisfied with the treatment outcome. Complications were reported by 44.2%. Patients who lost teeth due to periodontitis (n = 784) reported greater oral function improvement and better pre-treatment information, and were more likely to experience complications when compared with patients who lost teeth for other reasons (n = 515). Age, level of education, self-funded cost, pre-treatment information, history of complications and the reason for missing teeth were found to predict PROs.

CONCLUSIONS

In a Norwegian population rehabilitated with dental implants in 2014, satisfaction with the treatment outcome and the aesthetic outcome was high, irrespective of the reason for missing teeth. Self-report of complications and lack of pre-treatment information were the strongest predictors of inferior patient satisfaction and also predicted inferior oral function.

Evaluation of the trueness and precision of conventional impressions versus digital scans for the all-on-four treatment in the maxillary arch: An in vitro study

PURPOSE

To compare the accuracy of digitizing conventional impressions to intraoral surface scans for all-on-four treatment in the maxillary arch.

MATERIALS AND METHODS

An edentulous maxillary arch model with four implants placed in an all-on-four design was fabricated. Intraoral surface scans (n = 10) were obtained using an intraoral scanner after scan body insertion. For conventional polyvinylsiloxane impressions of the model, implant copings were inserted into the implant fixation for implant level, opened tray impressions (n = 10). The model and conventional impressions were digitized to obtain digital files. A reference file was created using a laboratory-scanned conventional standard tessellation language (STL) file with analog to scan the body using exocad software. STL datasets from the two digital and conventional impression groups were superimposed with reference files to assess the 3D deviations. Two-way ANOVA and paired-samples t-test was performed to assess the difference in trueness and examine the effects of impression technique and implant angulation on the deviation amount.

RESULTS

No significant differences were found between the conventional impression and intraoral surface scan groups F(1, 76) = 2.705, p = 0.104. No significant differences were found between conventional straight and digital straight implants and between conventional and digital tilted implants F(1, 76) = .041, p = 0.841. No significant differences were found between conventional straight and conventional tilted implants p = 0.07 and between digital straight and digital tilted implants p = 0.08.

CONCLUSION

Digital scans were more accurate than conventional impressions. The digital straight implants were more accurate than the conventional straight implants, and the digital tilted implants were more accurate than the conventional tilted implants, with higher accuracy for digital straight implants.

AI-Assisted Treatment Planning for Dental Implant Placement: Clinical vs AI-Generated Plans

Background

Dental implant placement is a critical procedure in modern dentistry, requiring precise treatment planning to ensure successful outcomes. Traditionally, treatment planning has relied on the expertise of clinicians, but recent advancements in artificial intelligence (AI) have opened up the possibility of AI-assisted treatment planning.

Materials and Methods

Twenty patients requiring dental implant placement were included in this comparative study. For each patient, a clinical treatment plan was created by an experienced dentist, while an AI algorithm, trained on a dataset of implant placement cases, generated an alternative plan. Various parameters, including implant position, angulation, and depth, were compared between the two plans. Surgical templates were fabricated based on both plans to guide implant placement accurately.

Results

The results of this study indicate that AI-generated treatment plans closely align with clinical plans in terms of implant positioning, angulation, and depth. Mean discrepancies of less than 1 mm and 2 degrees were observed for implant position and angulation, respectively, between the two planning methods. The AI-generated plans also showed a reduction in planning time, averaging 10 min compared to the clinical planning, which averaged 30 min per case. Additionally, the surgical templates based on AI-generated plans exhibited similar accuracy in implant placement as those based on clinical plans.

Conclusion

AI-assisted treatment planning for dental implant placement demonstrates promising results in terms of accuracy and efficiency.

Biomechanical analysis of peri-prosthetic bone response to hybrid threaded zirconia dental implants: An in silico model

The biomechanical response of mandibular bone determines primary stability and concomitant osseointegration of dental implants. This study explores the impact of nature of loading and bone conditions on biomechanical response of hybrid threaded single-piece zirconia dental implants. To develop such understanding, three implants (SQ_V, V_BUT, and V_V), with different combinations of threads, square (SQ), buttress (BUT), and triangular (V), have been investigated. Finite Element Analysis (FEA) was carried out to simulate implantation at the molar position of mandible of varying densities under axial (≤500 N) and oblique (118.2 N) loadings. Patient-specific bone conditions (for a wider population) were considered by scaling the density and the elastic modulus of mandible to represent, 'weak', 'healthy', and 'strong' bone conditions. FEA results revealed that SQ_V and V_BUT implants exhibited a better biomechanical response without significant variation (<0.5%) in von Mises stress, regardless of bone density and axial loadings. These implants are predicted to perform with clinically acceptable factor of safety under investigated implantation scenarios, whereas V_BUT implant showed a larger variation (∼±12%). FEA simulation with oblique loading further validated such results. The 'weak' bone conditions resulted in maximum peri-implant microstrain, whereas 'strong and healthy' bone exhibited values close to the permissible range of physiological remodeling. The maximum micromotion (∼12.3 ± 6.2 μm for 'weak' bone) at bone-implant interface suggested that implant loosening and impaired osseointegration will not occur in any of selected virtual implantation cases. Both SQ_V and V_BUT implants will be considered further in implant development, involving manufacturing and product prototype validation. Taken together, the critical analysis of FEA results indicates a significant impact of bone density and distinct combinations of external threads on the biomechanical responses, in both the implant and the surrounding bone.

The influence of vertical ridge augmentation techniques on peri-implant bone loss: A systematic review and meta-analysis

INTRODUCTION

The primary aim of this systematic review was to investigate and compare the outcomes of different vertical ridge augmentation (VRA) techniques in relation to peri-implant bone loss (PBL), after at least 12 months of functional loading.

MATERIAL AND METHODS

The search was conducted to find all the studies about VRA and measurements of PBL with at least 12 months follow-up. Three pairwise meta-analysis (MA) was performed to completely evaluate the outcomes.

RESULTS

A total of 42 studies were included, of which 11 were randomized clinical trials (RCTs). RCTs were available only for guided bone regeneration (GBR), onlay, and inlay techniques. The weighted mean estimate (WME) of PBL value was found to be 1.38 mm (95% confidence interval [95% CI]: 1.10-1.66) after a mean follow-up of 41.0 ± 27.8 months. GBR, Inlay, Onlay, osteodistraction, and SBB represented in weight 32.9%, 30.6%, 25.0%, 7.6%, and 3.9%, respectively; and their WME (95% CI) were 1.06 (0.87-1.26) mm, 1.72 (1.00-2.43) mm, 1.31 (0.87-1.75) mm, 1.81 (0.87-1.75) mm, and 0.66 (0.55-0.77) mm, respectively. Among the secondary outcomes, the analysis was conducted for vertical bone gain, healing complication rate, surgical complication rate, implant survival, and success rate.

CONCLUSIONS

The primary findings of the meta-analysis, based on the changes between final and baseline values, showed that the peri-implant bone loss could be influenced by the type of intervention but there is a need to evaluate in RCTs the behavior of the peri-implant bone levels after long-term follow-up for all techniques.

Effect of abutment screw-access hole on the fatigue performance of implant-supported lithium-disilicate luted simplified restorations

The present study aimed to evaluate the impact of the existence of an abutment screw-access hole and the filling effects on the fatigue mechanical behavior of a luted lithium-disilicate glass-ceramic. Seventy-two discs (Ø = 10 mm, 1.0 mm in thickness) of lithium disilicate (IPS e.max CAD, Ivoclar AG) were obtained from prefabricated blocks. Thirty-six abutment specimens of an opaque zirconia (Yz - IPS e.max ZirCAD, Ivoclar AG) and titanium (Ti - Luminesse Ti-Cam discs, Talladium Inc.) were confectioned, and allocated according to 6 groups: Yz and Ti rigid (without screw access hole); Yz unfilled, Yz filled, Ti unfilled and Ti filled (with the screw access (Ø = 2.5 mm) in the center). For the unfilled groups, only a polytetrafluoroethylene tape was used. Resin composite (Tetric N-Ceram, Ivoclar AG) was applied to the screw access hole for the filled groups (Yz and Ti). A cyclic fatigue test was carried out (load of 200 N, 10,000 cycles each; 20 Hz of frequency, step size of 100 N until failure detection (radial/cone crack). The fatigue failure load (FFL) and number of cycles until failure (CFF) were recorded for statistical purposes. The stress distribution (MPa) was evaluated by finite element analysis. A statistically positive effect of the abutment material and the presence of the screw access hole was observed (p ≤ 0.05). The rigid groups (without screw access holes) depicted almost 100% of survival after the fatigue tests. Among the other groups, the Yz-filled group showed the best performance (p ≤ 0.05), followed by the Yz unfilled group. The Ti groups depicted lower values of FFL and CFF, with the Ti unfilled group showing the most unfavorable fatigue behavior (p ≤ 0.05). The lowest tensile stress concentration in the restorative material was observed with the use of rigid abutments, the filled groups depicted intermediate values, while unfilled groups showed the highest stress concentration (Yz rigid = 306.3 MPa; Ti rigid = 310.4 MPa < Yz filled = 490.7 MPa; Ti filled = 498.9 MPa < Yz unfilled = 707.6 MPa; Ti unfilled = 719.7 MPa). Therefore, the presence of a screw-access hole decreases the mechanical performance of a lithium disilicate ceramic regardless of the abutment material. In the presence of a screw-access hole, zirconia abutments depicted a higher fatigue failure load when compared with titanium. The filling of the abutment screw-access hole with resin composite increased the mechanical performance of the simulated restoration.

An in vitro evaluation of 2 methods for retrieving fractured abutment screw fragments from the intaglio of 4 different implant systems

STATEMENT OF PROBLEM

When an abutment screw fractures, there is no standardized technique for retrieving it from the intaglio of the dental implant.

PURPOSE

The purpose of this in vitro study was to assess the relative efficacy of a commercially available screw fragment retrieval kit with a range of standard dental instruments in regard to success and retrieval time. In addition, the effects of other variables on the success rate of screw fragment retrieval and the retrieval time required were also investigated. Finally, the integrity of the intaglio screw channel of the dental implant was also assessed following retrieval.

MATERIAL AND METHODS

The abutment screws from 4 dental implant systems: Osseotite Certain, Ø4.1 mm (Zimmer Biomet); Osseotite External hexagonal connection micromini, Ø3.25 mm (Zimmer Biomet); Standard Plus Tissue Level, Ø4.8 mm (Institut Straumann AG); and Brånemark Mark III TiUnite, Ø4.1 mm (Nobel Biocare) had notches placed between the first and second coronal threads before being placed in their respective abutments, positioned in the dental implants (n=128), and tightened until the screws fractured. The dental implant specimens were placed in maxillary and mandibular casts at the lateral incisor and first molar sites on both sides. The casts were placed in mannequin heads on a dental chair and assigned to 2 experienced and 2 inexperienced operators who used 2 different retrieval kits to retrieve the screw fragments. Chisquared tests were used to determine the association between the success rate of screw fragment retrieval and the other factors recorded (α=.05), and a binary logistic regression was used to determine the association between the retrieval event and all of the independent variables. Regression models were developed to determine the factors effecting retrieval time.

RESULTS

An overall success rate of 88.3% was achieved for screw fragment retrieval. No statistically significant difference (P>.999) was found in the relative efficacy of the retrieval kits. Univariate analysis identified a statistically significant association (P<.01) in the success of abutment screw fragment retrieval between the Osseotite Certain and the Osseotite External hexagonal connection micromini implant systems. Gamma regression analysis identified significant differences between the time taken to retrieve the screw fragments and the type of dental implant (P<.001), (P<.01). The time taken to retrieve screw fragments in the maxillary arch was significantly longer than for the mandibular arch (P<.05).

CONCLUSIONS

The commercially available screw fragment retrieval kit and the standard dental instruments were equally effective in retrieving the screw fragments. Less time was required to retrieve screw fragments in the mandibular arch than the maxillary arch. The level of experience of the operator had no effect on the ability to successfully retrieve fractured abutment screws.

Surface, microstructural and mechanical characterization of contemporary implant abutment screws

OBJECTIVES

The aim of the present work was to evaluate six commercially available abutment screws by characterising roughness parameters, microstructure and mechanical properties.

METHODS

Six abutment screws from each implant system, were used. The surface roughness parameters (Sa, Sq, Ssk, Sku, Spk, Sk and Svk) were identified by an optical interferometric profiler. Microstructural observations and crystallographic analysis were performed using a scanning electron microscope (SEM) equipped with an energy dispersive X-ray spectroscopy (EDX) device for elemental analysis and an X-ray diffractometer (XRD), respectively. The Martens Hardness (HM), Indentation Modulus (EIT), elastic index (ηIT) and Vickers hardness (HV) of all specimens were determined by instrumented indentation testing (IIT). The results were analyzed by one-way ANOVA and Tukey multiple-comparison tests (a=0.05).

RESULTS

EDX and XRD showed the abutment screws to be mixed α- and β-phase titanium alloys. Microstructural analysis revealed a fine homogeneous microstructure without porosity, consisting of fine dispersoid rods of β-phase embedded in a continuous α-phase matrix. Statistically significant differences were found among the mechanical properies and surface roughness parameters apart from Sq, Spk and Svk.

CONCLUSIONS

The tested abutment screws showed significant differences in the probed properties, and, thus, differences in their clinical behaviour are anticipated.

Oral implant rehabilitation under general anesthesia for patients with cognitive and physical disabilities: A 14-year cohort study

STATEMENT OF PROBLEM

Oral rehabilitation with implants is an alternative to the provision of removable dentures in all patients for whom missing teeth require replacement. However, individuals with cognitive, mental health issues, and/or physical disabilities are often excluded from implant-supported prostheses because of the high perceived risk of failure linked to poor oral health, presence of parafunction, or systemic conditions.

PURPOSE

The purpose of this cohort study was to describe the protocols, outcomes, and survival rates of oral rehabilitation with implant-supported prostheses in patients with cognitive and physical disabilities treated under general anesthesia (GA) in a French unit of Special Care Dentistry.

MATERIAL AND METHODS

A retrospective cohort study was conducted on patient files. Data collected included demographics and information about the surgical and prosthetic phases of rehabilitation. Clinical and radiological reports were retrieved to establish the survival, success, and failure rates of implant placement according to the Health Scale for Dental Implants (HDSI) classification.

RESULTS

A total of 298 dental implants had been placed under GA in 57 patients between January 2007 and August 2021. The prevalence of technical and biological postoperative complications was found to be 14% and 13% respectively. Thirty implants were determined to be failures. The estimated survival time in the population studied for loaded implants was 144.7 months [138.0; 151.3]. The cumulative survival rate was estimated to be 86% at 157 months.

CONCLUSIONS

Implant-supported prostheses were found to be effective, and oral rehabilitation carried out under the conditions described was determined to be stable.

Implant-assisted removable partial dentures: Part II. a systematic review of the effects of implant position on the biomechanical behavior

PURPOSE

This systematic review aimed to evaluate the effects of implant placement sites on the biomechanical behavior of implant-assisted removable partial dentures (IARPDs) using finite element analysis (FEA).

STUDY SELECTION

Two reviewers independently conducted manual searches of the PubMed, Scopus, and ProQuest databases for articles investigating implant location in IARPDs using FEA, according to the 2020 Systematic Reviews and Meta-analyses statement. Studies published in English up to August 1, 2022, were included in the analysis based on the critical question.

RESULTS

Seven articles meeting the inclusion criteria were systematically reviewed. Six studies investigated mandibular Kennedy Class I and one study investigated mandibular Kennedy Class II. Implant placement reduced the displacement and stress distribution of the IARPD components, including dental implants and abutment teeth, regardless of the Kennedy Class type and dental implant placement site. Most of the included studies showed that, based on the biomechanical behavior, the molar region, rather than the premolar region, is the preferred implant placement site. None of the selected studies investigated the maxillary Kennedy Class I and II.

CONCLUSIONS

Based on the FEA regarding mandibular IARPDs, we concluded that implant placement in both the premolar and molar regions improves the biomechanical behaviors of IARPD components, regardless of the Kennedy Class. Implant placement in the molar region results in more suitable biomechanical behaviors compared with implant placement in the premolar region in Kennedy Class I. No conclusion was reached for Kennedy Class II due to the lack of relevant studies.

Implant-assisted removable partial dentures: Part I. a scoping review of clinical applications

PURPOSE

This scoping review aimed to systematically map research regarding implant-assisted removable partial dentures (IARPDs), and identify existing gaps in knowledge.

STUDY SELECTION

Two reviewers independently conducted a search of the MEDLINE-PubMed and Scopus databases according to the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) extension for Scoping Review and included articles published in English up to August 31, 2022, including human studies, reviews, and in vitro studies. Expert opinions, animal studies, and clinical studies involving complete overdentures were excluded, and ten aspects for establishing the treatment strategy for IARPDs were examined.

RESULTS

One hundred and twelve articles were chosen. There were two treatment modalities: IARPDs retained by implant- and tooth-supported surveyed single crowns (SCs) or fixed partial dentures (FPDs). In IARPDs retained by tooth-supported surveyed SCs or FPDs, the survival rate of dental implants for IARPDs was relatively higher with a wide range of marginal bone loss and many complications, but with improved functional performance, oral health-related quality of life, and patient satisfaction. There were limited data on survival or success rates and designs of IARPDs, attachment selections, length and diameter, inclination, placement sites, and loading protocols of implants, regardless of prosthetic types. There was limited information on maxillary IARPDs except for survival rates of implants.

CONCLUSIONS

Although IARPDs could become a useful treatment strategy, there is limited scientific consensus with gaps in knowledge about their use. Additional well-designed clinical and in vitro studies are necessary to scientifically establish IARPDs as definitive prostheses in implant dentistry.

The Influence of Genetic Polymorphisms on the Expression of Interleukin-1beta, Prostaglandin E2 and Tumor Necrosis Factor Alpha in Peri-Implant Crevicular Fluid: A Cross-Sectional Study

The aim of this study was to evaluate the possible relationships between polymorphisms in the interleukin-1 (IL-1) A, IL-1B, and IL-1RN genes and concentrations of the inflammatory mediators IL-1β, tumor necrosis factor-alpha (TNF-α), and prostaglandin E2 (PGE2) in peri-implant crevicular fluid (PICF). A cross-sectional analytical study was conducted on 51 patients with dental implants. Samples from the buccal mucosa were obtained, and genetic analysis was performed using the real-time polymerase chain reaction (PCR) technique for IL-1A and IL-1B and PCR and restriction fragment length polymorphism analysis for IL-1RN. For the biochemical analysis, the concentrations of IL-1β and TNF-α were analyzed using multiplexed fluorescent sphere immunoassays, and PGE2 by enzyme-linked immunosorbent assay. In patients with detected IL-1RN polymorphism, there was an increase in the concentration of the three mediators with statistically significant differences in the mean values of TNF-α and PGE2, regardless of peri-implant health status (p = 0.002 and p = 0.049, respectively). The concentrations of all three mediators were positively and significantly correlated (IL-1β vs. TNF-α Rho = 0.480, p < 0.001; IL-1β vs. PGE2 Rho = 0.382, p = 0.006; and TNF-α vs. PGE2 Rho = 0.528, p < 0.001). We can conclude that the IL-1RN polymorphism exerts an influence on the PICF immune response, which may explain the influence of this genetic polymorphism on the occurrence of peri-implantitis.

Survival and Success of Dental Implants in Patients with Autoimmune Diseases: a Systematic Review

Objectives

The purpose of this systematic review is to disclose the impact of autoimmune diseases and their medical treatment on dental implant survival and success.

Material and Methods

A literature search was conducted using MEDLINE (PubMed), The Cochrane Library and Embase up to December 6th, 2021. Any clinical study on patients with an autoimmune disease in whom implant therapy was performed was eligible. The quality of included studies was assessed using the Newcastle-Ottawa Scale. For each autoimmune disease group, data synthesis was divided into three groups: 1) overall results of the autoimmune disease, 2) overall results of corresponding control groups and 3) overall results of the autoimmune disease with a concomitant autoimmune disease (a subgroup of group 1). Descriptive statistics were used.

Results

Of 4,865 identified articles, 67 could be included and mainly comprising case reports and retrospective studies with an overall low quality. Implant survival rate was 50 to 100% on patient and implant level after a weighted mean follow-up of 17.7 to 68.1 months. Implant success was sporadically reported. Data on immunosuppressive medication were too heterogeneously reported to allow detailed analysis.

Conclusions

Overall, a high implant survival rate was reported in patients with autoimmune diseases. However, the identified studies were characterized by a low quality. No conclusions could be made regarding implant success and the effect of immunosuppressants due to heterogeneous reporting.

Impact of profile angle of CAD-CAM abutment on the marginal bone loss of implant-supported single-tooth posterior restorations

STATEMENT OF PROBLEM

Although the emergence angle has been related to marginal bone loss, information regarding the relationship between the transmucosal configuration of a computer-aided design and computer-aided manufacturing (CAD-CAM) abutment at specific subgingival levels and the amount of marginal bone loss is lacking.

PURPOSE

The purpose of this retrospective clinical study was to evaluate the influence of CAD-CAM abutment profile angles, measured at different subgingival positions, on the marginal bone loss of posterior single-tooth implant-supported restorations.

MATERIAL AND METHODS

A total of 260 posterior single-tooth implant-supported restorations using CAD-CAM abutments were analyzed in 206 patients. All implants had internal conical seal connections with a platform-switched design. The following data were extracted using digital periapical radiography: emergence profile, profile angle at distance ranges of 0 to 1 mm, 1 to 2 mm, and 2 to 3 mm from the implant-abutment junction, and peri-implant marginal bone loss (MBL). The MBL was measured from the time of delivery of the restorations up to 7 years or more. A linear mixed model was applied to investigate whether there was a significant difference in MBL based on the emergence profile and time, followed by the Bonferroni correction post hoc test. A Pearson correlation analysis was used to analyze the correlation between the profile angle and MBL at each distance range. The cut-off points for each distance range were determined by using the c-index, and independent t tests were conducted based on these cut-off values to evaluate the statistical differences (α=.05 for all statistical analyses).

RESULTS

The convex emergence profile exhibited greater MBL than the concave and straight profiles at each follow-up visit (P<.001). A significant correlation was found between the profile angle and MBL in the 0 to 1 mm, 1 to 2 mm distance ranges. However, no significant correlation was found between the profile angle and MBL in the 2 to 3 mm distance range (P>.05). The cut-off points were 34 degrees at the mesial and 28 degrees at the distal in the 0 to 1 mm range, and 33 and 20 degrees at the mesial and distal in the 1 to 2 mm range.

CONCLUSIONS

The profile angle near the implant-abutment junction and the type of emergence profile of the CAD-CAM abutment were closely associated with MBL in implants with internal conical seal connection with a platform switch design.

Characteristics and Risk Factors for the Fracture of One-Piece Implants

Objective

The one-piece dental implant was originally designed to overcome the structural weaknesses of the two-piece implant. However, a fractured one-piece implant requires removal because the abutment cannot be repaired or replaced to support new prosthetic restorations. The aim of this study was to clarify the features and risk factors for fracture of the one-piece implant.

Methods

This study was designed as a retrospective case series research. The subjects were patients who were treated for fractures of the one-piece implant at a clinic in Japan between 2012 and 2021. Fractures of the one-piece implant were diagnosed by cone-beam computed tomography, and the association between age and duration from implant placement to fracture was analyzed by one-way ANOVA followed by the Tukey test.

Results

Eighteen patients and 20 one-piece implants (under 39 years: 5 patients and 6 implants; 40-59 years: 7 patients and 7 implants; over 60 years: 6 patients and 7 implants) had fractures in their one-piece implants. Of the fractured implants, 11 had a diameter of 3 mm, and 9 had a diameter of 4 mm. The mean durations up to implant fracture were 662 days in the younger group, 1467 days in the middle group, and 1239 days in older group, and the duration was significantly shorter in the younger group. In addition, 83.3% of fracture implants in the younger group were in the molar region. All fractures of the one-piece implants occurred under the bone margin. Two patients had torus mandibularis, and 1 patient was had bruxism.

Conclusions

One-piece implants in younger patients that are located in the lower molar position are the most susceptible to implant fracture, and the fracture occurred under the bone margin in all cases.

The influence of implant position and of prosthetic characteristics on the occurrence of peri-implantitis: a retrospective study on periapical radiographs

OBJECTIVE

The present retrospective study aimed to investigate the influence of malposition on the occurrence of peri-implantitis.

MATERIALS AND METHODS

The study included clinical records of systemically healthy patients with single and partial implant-supported rehabilitations and at least 1-year post-loading follow-up. The parameters collected included implant-related factors, patient-related factors, site-related factors, and prosthesis-related factors. The radiographic measurements were taken by using a dedicated software and the diagnosis of peri-implantitis was made based on all the available clinical and radiographic data. Descriptive statistics were provided for all variables. Following an exploratory approach, an implant-level analysis of factors influencing the occurrence of peri-implantitis was done through a multilevel multivariate logistic regression (mixed).

RESULTS

A total of 180 implants belonging to 90 subjects were randomly selected. Malposition showed no statistically significant association with the occurrence of peri-implantitis. According to the multi-level analysis, the parameters that were significantly associated with peri-implantitis included presence / history of periodontitis (OR = 5.945, 95% CI: 1.093 - 32.334, P = 0.039) and presence of an emergence profile angle ≥ 45° (OR = 9.094, 95% CI: 2.017 - 40.995, P = 0.005).

CONCLUSIONS

Implant malposition, as defined following Buser's criteria (2004), did not influence the occurrence of peri-implantitis in the selected cohort. Conversely, history of periodontitis and presence of a prosthetic emergence profile with an angle ≥ 45° were correlated to an increased risk of peri-implantitis.

Survival and complication rates of two dental implant systems supporting fixed restorations: 10-year data of a randomized controlled clinical study

OBJECTIVES

To compare clinical, radiographic, biological and technical long-term outcomes of two types of dental implants over a period of 10 years.

MATERIALS AND METHODS

Ninety-eight implants were placed in 64 patients, randomly allocated to one of two manufacturers (AST and STM). All implants were loaded with fixed restorations. Outcome measures were assessed at implant insertion (Ti), at baseline examination (TL), at 1, 3, 5, 8 and 10 (T10) years. Data analysis included survival, bone level changes, complications and clinical measures.

RESULTS

Re-examination was performed in 43 patients (23 AST and 20 STM) at 10 years. The implant level analysis was based on 37 (AST) and 32 (STM) implants. Survival rates of 100% were obtained for both groups. The median changes of the marginal bone levels between baseline and T10 (the primary endpoint) amounted to a loss of 0.07 mm for group AST and a gain of 0.37 mm for group STM (intergroup p = 0.008). Technical complications occurred in 27.0% of the implants in group AST and in 15.6% in group STM. The prevalence of peri-implant mucositis was 29.7% (AST) and 50.1% (STM). The prevalence of peri-implantitis amounted to 0% (AST) and 6.3% (STM).

CONCLUSIONS

Irrespective of the implant system used, the survival rates after 10 years were high. Minimal bone level changes were observed, statistically significant but clinically negligible in favor of STM. Technical complications were more frequently encountered in group AST, while group STM had a higher prevalence of peri-implant mucositis.

Accuracy of fit for cobaltchromium bar over two implants fabricated with different manufacturing techniques: an in-vitro study

OBJECTIVE

The purpose of the invitro research was to compare the fit of Cobalt Chromium customized bar fabricated with different manufacturing processes cast metal bar, milled bar and 3D printed bar using scanning electron microscope.

MATERIALS AND METHODS

Clear epoxy resin molds were prepared. In each mold two parallel implants with a 14 mm distance from each other were embedded. Thirty Co-Cr custom bars were constructed and were divided equally into three groups: Group (I) (Co-Cr conv), group (II) milled bar (Co-Cr milled), and group (III) printed bar (Co-Cr print). The marginal fit at implant-abutment interface was scanned using scanning electron microscope (SEM).

RESULTS

There was a significant difference between the three studied groups regarding marginal misfit the between implant and fabricated bars with p-value < 0.001. The highest value of micro-gap distance was found in Co-Cr conventional group (7.95 ± 2.21 μm) followed by Co-Cr 3D printed group (4.98 ± 1.73) and the lower value were found in Co-Cr milled (3.22 ± 0.75).

CONCLUSION

The marginal fit of milled, 3D printed and conventional cast for Co-Cr alloy were within the clinically acceptable range of misfit. CAD/CAM milled Co-Cr bar revealed a superior internal fit at the implant-abutment interface. This was followed by selective laser melting (SLM) 3D printed bar and the least fit was shown for customized bar with the conventional lost wax technique.

Clinical efficacy of computer-assisted zygomatic implant surgery: A systematic scoping review

STATEMENT OF PROBLEM

Digital technology can improve the success of zygomatic implant (ZI) surgery. However, the reliability and efficacy of computer-assisted zygomatic implant surgery (CAZIS) need further analysis.

PURPOSE

The purpose of this scoping review was to provide an overview of the placement accuracy, implant survival, and complications of CAZIS.

MATERIAL AND METHODS

A systematic search of English and Mandarin Chinese publications up to May 2023 was conducted in PubMed, Web of Science, Embase, and Wanfang database. The nonpeer-reviewed literature was searched in the trial register (clinicaltrials.gov). Clinical studies and cadaver studies on CAZIS were included. After data extraction and collection, the findings were critically reviewed, analyzed, interpreted, and discussed.

RESULTS

Forty-one studies met the inclusion criteria. After excluding publications with duplicate data, retaining the most recent, 28 articles were included in this scoping review. Of these, 18 were on static computer-assisted zygomatic implant surgery (sCAZIS), 8 on dynamic computer-assisted zygomatic implant surgery (dCAZIS), and 2 on robot-assisted zygomatic implant surgery (rAZIS). Excluding the outliers, the mean deviations of ZIs in the sCAZIS group (with 8 articles reporting implant placement accuracy, 183 ZIs involved) were: 1.15 ±1.37 mm (coronal deviation), 2.29 ±1.95 mm (apical deviation), and 3.32 ±3.36 degrees (angular deviation). The mean deviations of dCAZIS (3 articles, 251 ZIs) were: 1.60 ±0.74 mm (coronal), 2.27 ±1.05 mm (apical), and 2.89 ±1.69 degrees (angular). The mean deviations of rAZIS (2 articles, 5 ZIs) were: 0.82 ±0.21 mm (coronal), 1.25 ±0.52 mm (apical), and 1.46 ±0.35 degrees (angular). Among the CAZIS reported in the literature, the implant survival rate was high (96.3% for sCAZIS, 98.2% for dCAZIS, and 100% for rAZIS, specified in 14 of 21 clinical studies). The incidence of complications was low, but, because of the few relevant studies (4/21 specified), valid conclusions regarding complications could not be drawn.

CONCLUSIONS

CAZIS has demonstrated clinical efficacy with high implant survival rates and placement accuracy. Of the 3 guided approaches, rAZIS showed the smallest 3-dimensional deviation.

Alumina and glass-bead blasting effect on bond strength of zirconia using 10-methacryloyloxydecyl dihydrogen phosphate (MDP) containing self-adhesive resin cement and primers

In fact, bonding of zirconia restorations is still a big challenge in clinical situations and many bonding protocols discussed in literature might be still controversial. The aim of this was to study assess the bond strength of zirconia after alumina and glass-bead pre-treatments with two different primers in combination with conventional resin cement and 10-methacryloyloxydecyl dihydrogen phosphate (MDP) containing self-adhesive resin cement without priming. Fully sintered high translucent zirconia samples (n = 160) were assigned into 2 groups of pre-treatments (n  = 80): Alumina-sandblasting (AB) and Glass-bead (GB). Then, each group was divided into 4 sub-groups according to priming and cement used (n  = 20 each): conventional self-adhesive resin cement, MDP-silane Primer, MDP primer both with conventional self-adhesive resin cement, and MDP contained cement. Shear bond strength (SBS) was measured after thermocycling. Failure mode was analyzed using stereomicroscope. Contact angle and surface topography were investigated using other fully sintered samples (n  = 30) constructed for that sole purpose, divided into control (no pre-treatment [unmodified], alumina-, and glass-bead sandblasted groups). Two-way ANOVA was performed for SBS and failure mode was analyzed. The use of Alumina-sandblasting showed higher SBS compared to Glass-bead pre-treatment for MDP-silane primer (p = 0.034) and MDP primer (p < 0.001). While MDP contained cement showed higher but insignificant SBS when pre-treated with glass-beads. Alumina-sandblasting and glass-bead pre-treatments improve bond strength of zirconia combined using primers before cementation with conventional resin cement. Also, self-adhesive MDP contained cement along with surface pre-treatment showed the highest achievable bond strength. It was concluded that both alumina-sandblasting and glass-bead blasting improved SBS combined with MDP containing self-adhesive resin cement reducing the required clinical steps during cementation of zirconia restorations.

Survival and success of zirconia compared with titanium implants: a systematic review and meta-analysis

OBJECTIVE

This systematic review assessed the available evidence on the survival and success rate of zirconia and titanium implants. As secondary outcomes, aesthetic, radiographic and clinical parameters, as well as biological and mechanical complications, were considered.

MATERIALS AND METHODS

A systematic search was performed up to March 2022 to identify CCTs/RCTs comparing zirconia and titanium implants with a minimum of 12 months of follow-up. Meta-analysis was performed when ≥ 2 articles with similar characteristics were retrieved.

RESULTS

Four published articles with two RCTs (2 different patient populations) with 100 zirconia and 99 titanium implants that were followed up over 12-80 months were selected out of the 6040 articles. A non-statistically significant difference between zirconia and titanium implant survival at 12 months was suggested (P = 0.0938). The success rates were 57.5-93.3% and 57.1-100% for zirconia and titanium implants, respectively. The pink aesthetic score (PES) was higher for zirconia (10.33 ± 2.06 to 11.38 ± 0.92) compared to titanium implants (8.14 ± 3.58 to 11.56 ± 1.0).

CONCLUSION

Based on the 2 RCTs retrieved in the literature, similar survival rates were reported for zirconia and titanium implants in the short term (12 months of follow-up). Future RCTs are warranted to evaluate the long-term outcomes of zirconia implants.

CLINICAL RELEVANCE

Zirconia implants may be the procedure of choice, particularly in the aesthetic zone, since they show a similar survival and success rate as titanium implants on a short-term follow-up.

TRIAL REGISTRATION

Systematic review registration number-CRD42021288704 (PROSPERO).

Medication-related Osteonecrosis of the Jaw Induced by Regenerative Therapy in Implant Dentistry: A Scoping Review

OBJECTIVES

There is limited scientific evidence regarding the medication-related osteonecrosis of the jaw (MRONJ) induced by regenerative therapy (RT) associated with dental implant treatment. Thus, the current scoping review systematically maps the MRONJ research induced by RTs in implant dentistry and recognizes the existing gaps in knowledge.

DATA

Original studies and reviews investigating the impact of RT on the development of MRONJ were included.

SOURCES

Two reviewers independently searched the MEDLINE-PubMed and Scopus databases according to the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) extension for Scoping Review and included articles published in English up to March 31, 2023.

STUDY SELECTION

Eighteen articles that fulfilled the inclusion and exclusion criteria were included in this study. Ten mapping parameters for investigating the association of RTs with MRONJ development were examined and evaluated within the selected articles.

RESULTS

There was severely limited information regarding the procedures of RTs including; the grafting materials, surgical protocols, and success and failure rates. The RT associated with MRONJ cases was sinus floor augmentation in patients taking bisphosphonate and denosumab. Moreover, there were limited data on the implant treatment associated with RTs such as time of insertion, implant length and diameter, and loading protocol.

CONCLUSION

The current scoping review revealed that some specific RTs associated with other factors hold a potential risk of MRONJ occurrence. However, the scientific evidence is limited with many gaps. Further investigations are needed to establish an evidence-based clinical guideline for treating high-risk patients.

CLINICAL SIGNIFICANCE

Clinicians should cautiously assess the risk of MRONJ development during implant treatment planning for patients undertaking antiresorptive medications. The adverse outcome of RT procedures should not be underestimated and a complete explanation of the possible risks should be given to the patients.

The preliminary in vitro study and application of deep learning algorithm in cone beam computed tomography image implant recognition

To properly repair and maintain implants, which are bone tissue implants that replace natural tooth roots, it is crucial to accurately identify their brand and specification. Deep learning has demonstrated outstanding capabilities in analysis, such as image identification and classification, by learning the inherent rules and degrees of representation of data models. The purpose of this study is to evaluate deep learning algorithms and their supporting application software for their ability to recognize and categorize three dimensional (3D) Cone Beam Computed Tomography (CBCT) images of dental implants. By using CBCT technology, the 3D imaging data of 27 implants of various sizes and brands were obtained. Following manual processing, the data were transformed into a data set that had 13,500 two-dimensional data. Nine deep learning algorithms including GoogleNet, InceptionResNetV2, InceptionV3, ResNet50, ResNet50V2, ResNet101, ResNet101V2, ResNet152 and ResNet152V2 were used to perform the data. Accuracy rates, confusion matrix, ROC curve, AUC, number of model parameters and training times were used to assess the efficacy of these algorithms. These 9 deep learning algorithms achieved training accuracy rates of 100%, 99.3%, 89.3%, 99.2%, 99.1%, 99.5%, 99.4%, 99.5%, 98.9%, test accuracy rates of 98.3%, 97.5%, 94.8%, 85.4%, 92.5%, 80.7%, 93.6%, 93.2%, 99.3%, area under the curve (AUC) values of 1.00, 1.00, 1.00, 1.00, 1.00, 1.00, 1.00, 1.00, 1.00. When used to identify implants, all nine algorithms perform satisfactorily, with ResNet152V2 achieving the highest test accuracy, classification accuracy, confusion matrix area under the curve, and receiver operating characteristic curve area under the curve area. The results showed that the ResNet152V2 has the best classification effect on identifying implants. The artificial intelligence identification system and application software based on this algorithm can efficiently and accurately identify the brands and specifications of 27 classified implants through processed 3D CBCT images in vitro, with high stability and low recognition cost.

Implant-supported prostheses in patients with special needs: A systematic literature review of protocols and outcomes

STATEMENT OF PROBLEM

Implant-supported prostheses for individuals with special needs have been considered high-risk because of the prevalence of poor oral hygiene and parafunction in this population; however, systematic evidence on protocols and outcomes is scarce.

PURPOSE

The purpose of this systematic review was to summarize implant procedures and outcomes for the special needs population.

MATERIAL AND METHODS

A systematic literature review was conducted using PubMed, Embase, and Scopus databases in accordance with the preferred reporting items for systematic reviews and meta-analyses (PRISMA) methodological framework. Data collected included patient information, location and number of implants, surgical and prosthetic procedures, behavior support techniques, postoperative follow-up, complications, and criteria for outcome assessment. Survival rates were pooled for quantitative analysis, and a separate analysis pooling data from groups of special needs patients that present similar risks was undertaken.

RESULTS

The qualitative analysis included 79 studies involving 759 patients and 2269 implants. The quantitative analysis included 65 studies concerning 666 patients with special needs and 1886 implants. The overall weighted implant survival rate was 95.4%, with a mean follow-up duration of 40.7 ±29.5 months.

CONCLUSIONS

In individuals with special needs considered suitable for implant-supported prostheses by their clinician, implant survival rates were similar to those reported in the general population. (J Prosthet Dent xxxx;xxx:xxx-xxx).

Screw-retained internal connection zirconia CAD-CAM abutments in single implant reconstructions: Results of a 1-year prospective case series study

PURPOSE

To evaluate the clinical and radiographic outcomes of single-tooth implant restorations using one-piece, internally connected, screw-retained, computer-aided design and computer-aided manufactured monolithic zirconia restorations fabricated on regular diameter implants.

MATERIAL AND METHODS

Following a 2-stage surgical procedure, 22 implants placed in anterior and posterior areas in 21 partially edentulous patients (mean age of 55 years; 9 males/12 females) were evaluated in terms of plaque index, pocket probing depth, bleeding on probing, level of oral hygiene (OH), signs of mucositis/peri-implantitis, esthetic score (ES), gingival zenith position (GZP), papilla index score, the thickness of peri-implant gingiva, radiographic marginal bone loss, and technical complications. Implants and restorations were prospectively followed from the insertion of the restoration (baseline), up to 12-months post-loading.

RESULTS

A 100% implant survival rate resulted after loading; one implant was lost before loading. Clinically, patients performed an adequate OH, and tissues were kept healthy. Probing depth showed a slightly lower value at baseline compared to any follow-up examination (2.26 [0.94] at baseline vs. 2.53 [0.66] mm at 12 months). ES, GZP, and the thickness of the peri-implant gingiva improved throughout the course of the study. Radiographically, average marginal bone level (MBL) was 0.40 (0.40) mm after 1-year follow-up with no differences in average MBL at all time points. Technically, after 1 year of clinical function, neither abutment fracture nor any other serious complications occurred. Hence, prosthetic reconstruction survival rate was 100%.

CONCLUSIONS

Clinical outcomes of single-tooth implant restorations using internally connected, screw-retained, computer-aided design and computer-aided manufacturing monolithic zirconia abutments can be considered a reliable treatment alternative after 1-year clinical observation.

An additively manufactured, magnetically retained, and stackable implant surgical guide: A dental technique

The digital workflow for designing and fabricating a magnetically retained and stackable additively manufactured implant surgical guide is described. The technique should improve the stability of the stackable surgical guide and the accuracy of implant placement.

Influence of varying titanium base abutment heights on retention of zirconia restorations: An in vitro study

STATEMENT OF PROBLEM

Implant manufacturers have introduced titanium base (Ti-Base) abutments with increased abutment heights, ostensibly, to increase the retention of the bonded restoration and to improve overall strength. However, evidence regarding the effects of increasing Ti-Base height on improving retention is lacking.

PURPOSE

The purpose of this in vitro study was to evaluate the effect of different Ti-Base abutment heights on the retention of zirconia implant-supported crowns.

MATERIAL AND METHODS

Thirty Ti-Base abutments of the same diameter and heights of 3.5 mm (n=10), 4.5 mm (n=10), and 5.5 mm (n=10), were used for testing. Zirconia restorations were cemented onto the Ti-Base abutments with a resin cement after treatment with a 10-methacryloyloxydecyl dihydrogen phosphate primer by a single operator using a positioning device. The zirconia-Ti-Base restorations were tightened to an implant analog embedded in an autopolymerizing resin block. The specimens were placed and tested in a universal testing machine for pull-out testing. Retention was measured by recording the force at load drop. Statistical analysis was performed using 1-way analysis of variance with the Tukey method for pairwise comparisons.

RESULTS

The abutment height had a significant effect on retention (P=.010). Ti-Base abutments of 4.5 and 5.5 mm had significantly greater retention than Ti-Base abutments of 3.5 mm (P=.020, P=.040, respectively). However, Ti-Base abutments of 4.5 and 5.5 mm in height were statistically similar (P=.890).

CONCLUSIONS

An increase in the height of Ti-Base abutments above the standard 3.5 mm height significantly improved the retention of the overlying restoration.

Critical review on bone grafting during immediate implant placement

In the last 20 years, immediate implant placement has been proposed as a predictable protocol to replace failing teeth. The research conducted in preclinical and clinical studies have focused on soft and hard tissue changes following tooth extraction and immediate implant placement. Different approaches for hard and soft tissue grafting together with provisional restorations have been proposed to compensate tissue alterations. This review analyzed some relevant clinical and preclinical literature focusing on the impact of bone grafting procedures on immediate implant placement in terms of hard and soft tissue changes, aesthetic results, and patient-related outcomes.

The clinical use of computer aided designed/computer aided manufactured titanium nitride coated implant abutments: Surgical and prosthetic considerations-A case series

OBJECTIVE

To describe the clinical use of nitride-coated titanium CAD/CAM implant abutments in the maxillary esthetic zone in two patients with high esthetic and functional demands and, to highlight the advantages of nitride-coated milled titanium abutments when compared to stock/custom titanium, one-piece monolithic zirconia, and hybrid metal-zirconia implant abutments.

CLINICAL CONSIDERATIONS

Due to the inherent mechanical and esthetic clinical challenges, single implant-supported reconstructions in the maxillary esthetic zone are a complex restorative treatment. While CAD/CAM technology has been suggested to enhance and ease implant abutment design and manufacturing, implant abutment material selection remains as a critical decision affecting restoration's long-term clinical outcomes. To date, considering the esthetic disadvantages of conventional titanium implant abutments, the mechanical limitations of one-piece zirconia abutments and the manufacturing time and costs associated with hybrid metal-zirconia abutments, no abutment material can be considered "ideal" for all clinical scenarios. Due to their biocompatibility, biomechanical characteristics (hardness and wear resistance), optical properties (yellow color), and peri-implant soft tissue esthetic integration, the use of CAD/CAM titanium nitride-coated implant abutments has been suggested as a predictable implant abutment material in mechanically challenging but esthetically demanding clinical situations, as the maxillary esthetic zone.

CONCLUSIONS

Two patients requiring a combined tooth-implant restorative treatment in the maxillary esthetic zone were treated using CAD/CAM nitride coated titanium implant abutments. The principal advantages of TiN coated abutments include comparable clinical outcomes to stock abutments, optimal biocompatibility, adequate fracture, wear, and corrosion resistance, reduced bacterial adhesion, and excellent esthetic integration with adjacent soft tissues.

CLINICAL SIGNIFICANCE

Clinical reports and short term mechanical, biological and esthetic clinical outcomes indicate that CAD/CAM nitride coated titanium implant abutments can represent a predictable restorative alternative to stock/custom and metal/zirconia implant abutments and be considered a clinical relevant option in mechanically challenging but esthetically demanding situations, as often found in the maxillary esthetic zone.

Root-analogue implants compared to forced orthodontic extrusion: a retrospective analysis of clinical, radiological and esthetic outcomes after restoration

OBJECTIVES

To assess clinical, radiological and esthetic outcomes of restorations supported by root-analogue implants (RAIs) or roots of severely damaged teeth after forced orthodontic extrusion (FOE).

MATERIALS AND METHODS

Clinical data regarding milled one-piece (titanium/zirconia roots and zirconia abutments) RAIs (REPLICATE™ System) and FOE were recorded and retrospectively evaluated for 40 patients by two investigators. Strict inclusion and exclusion criteria were applied. Functional and esthetic outcomes were assessed for n = 20 pre-molars and n = 20 anterior teeth via comparison of radiographic and digital images applying the novel Functional Implant Prosthodontic Score (FIPS). Krippendorff's alpha coefficient was calculated to assess inter-rater reliability. Mann-Whitney-U-Test was used to compare the assessed parameters. Level of significance was set to p < 0.05.

RESULTS

After a mean observation period of 18.4 ± 5.7 months for restorations supported by RAIs and 43.9 ± 16.4 months for restorations after FOE, mean FIPS scores were 9.2/8.8 ± 1.1/1.2 (RAIs) and 7.4/7.7 ± 1.3/1.5 (FOE), respectively. Krippendorff's alpha coefficients did not reveal unacceptable inter-rater reliabilities regarding the investigators and applicability of FIPS. Significant differences were documented when comparing restorations after FOE or supported by RAIs regarding bone loss (p < 0.01), presence of papillae (p < 0.05) and quality and quantity of mucosa (p < 0.02) in favor of FOE.

CONCLUSIONS

Within the main limitations of sample size and the retrospective study design, both concepts seem to provide clinically acceptable results.

CLINICAL RELEVANCE

Bone- and tissue-preserving characteristics regarding the concept of FOE are promising. It could be applicable for socket preservation and subsequent conventional implant placements in an adapted workflow.

Effect of print orientation, storage conditions, and storage time on intaglio surface accuracy of implant surgical guides fabricated by using a stereolithography technology

STATEMENT OF PROBLEM

The accuracy of printed implant surgical guides can be affected by different factors that negatively impact the planned implant position. How print orientation, storage time, and conditions influence manufacturing accuracy remains uncertain.

PURPOSE

The purpose of this in vitro study was to evaluate the influence of print orientation, storage conditions, and storage time on the intaglio surface accuracy of implant surgical guides manufactured by using a stereolithography (SLA) printer.

MATERIAL AND METHODS

A tooth-supported maxillary implant surgical guide design (control file) was used to fabricate the specimens (N=40, n=10). Four groups were created based on the print orientation used: 0 (Group 0), 45 (Group 45), 70 (Group 70), and 90 degrees (Group 90). The specimens were fabricated using an SLA printer (Form 3B+) and a biocompatible dental resin (Surgical Guide Resin V1) following the manufacturer's recommended protocol. Each group was divided into 2 subgroups based on the storage conditions: light (L subgroup) and dark (D subgroup) settings. Each specimen was digitized by using a desktop scanner (Medit T710) at days 0, 1, 7, and 14. The control file and each digitized specimen were superimposed by using the best-fit technique with a metrology program (Geomagic Control X). The root mean square (RMS) error was used to calculate the discrepancies between the control files and specimen files. Three-way ANOVA and pairwise comparison Tukey tests were used to analyze trueness. The Levene test was used to assess precision (α=.05).

RESULTS

Significant trueness discrepancies were found among the groups tested (P<.001), but no significant differences were found among the subgroups (P=.100) and the storage times analyzed (P=.609). Additionally, the Tukey test showed significant RMS error mean value discrepancies between Group 0 and Group 45 (P<.001), Group 0 and Group 90 (P<.001), Group 45 and Group 70 (P<.001), and Group 70 and Group 90 (P<.001). The Levene test revealed significant SD discrepancies among the groups tested (P<.05).

CONCLUSIONS

The trueness and precision of the intaglio surface of the implant surgical guides manufactured by using the printer and material tested were affected by the print orientation. However, storage conditions over a 14-day period did not impact the intaglio accuracy of the specimens.

In Vitro Biofilm Formation on Zirconia Implant Surfaces Treated with Femtosecond and Nanosecond Lasers

(1) Background: The purpose of this study was to evaluate how a zirconia implant surface treated with laser technology affects the degree of biofilm formation. (2) Methods: Experimental titanium (Ti) disks were produced that were sandblasted with large grit and acid-etched (T), and they were compared with zirconia (ZrO2) discs with a machined (M) surface topography; a hydrophilic surface topography with a femtosecond laser (HF); and a hydrophobic surface topography with a nanosecond laser (HN) (N = 12 per surface group). An in vitro three-species biofilm sample (Aggregatibacter actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi)) was applied to each disc type, and bacterial adhesion was assessed after 48 and 72 h of incubation using an anaerobic flow chamber model. Statistical significance was determined using the Kruskal-Wallis H test, with Bonferroni correction used for the post-hoc test (α = 0.05). (3) Results: Compared to the T group, the M group exhibited more than twice as many viable bacterial counts in the three-species biofilm samples (p < 0.05). In comparison to the T group, the HF group had significantly higher viable bacterial counts in certain biofilm samples at 48 h (Aa and Pi) and 72 h (Pi) (p < 0.05). The HN group had higher viable bacterial counts in Pi at 48 h (5400 CFU/mL, p < 0.05) than the T group (4500 CFU/mL), while showing significantly lower viable bacterial counts in Pg at both 48 (3010 CFU/mL) and 72 h (3190 CFU/mL) (p < 0.05). (4) Conclusions: The surface treatment method for zirconia discs greatly influences biofilm formation. Notably, hydrophobic surface treatment using a nanosecond laser was particularly effective at inhibiting Pg growth.