Clinical and Radiologic Outcomes after Submerged and Transmucosal Implant Placement with Two-Piece Implants in the Anterior Maxilla and Mandible: 3-Year Results of a Randomized Controlled Clinical Trial

10 Years of Convergent Neck Implants: A Systematic Review of Clinical Outcomes, Initial Original Concepts, and Changes in Surgical and Prosthetic Protocols

The study reviewed the state of the art of the clinical use of a convergent-neck-designed Prama implant. This implant was introduced approximately 10 years ago and was characterized by a specific and unique convergent neck with a microtextured surface (UTM surface) and Zirconium Titanium (ZirTi) implant body surface. The neck design was developed to adopt the biologically oriented preparation technique (BOPT). A critical analysis of the published clinical studies and an evaluation of the adopted clinical protocols were performed. A total of forty-six articles were eligible to be reviewed. Only sixteen clinical studies reported clinical outcomes on Prama implants, and nine of these were selected having the longest follow-up from different research groups. The clinical follow-up/duration of the studies ranged from 12 months to 6 years. The initially proposed protocols explored neck supracrestal–transmucosal placement and gained interest due to its minimally invasive concept and the ability to proceed without a pre-prosthesis second surgery. The following investigations dedicated attention to the subcrestal or equicrestal implant placement with the conventional flap approach. The clinical studies characterized by the transmucosal exposed neck approach reported high survival rates with a stable bone morphology and reduced bone loss during the follow-up. Further recent implementations included the introduction of different convergent neck heights that need to be evaluated. The use of intraoral scanner technologies and digital workflow resulted in a simpler methodology with control of the marginal crown morphology. The studies support the concept that the hard tissue parameters (such as marginal bone level, MBL) and soft tissue parameters (such as pink esthetic score, PES) were stable or improved during the follow-up. Definitive crowns, designed with low invasiveness for soft tissues, were possible thanks to the morphology of the neck. The clinical studies support the use of the Prama implant with the different neck positions, demonstrating hard tissue preservation and optimal esthetic results in the first years following insertion. However, the current body of evidence is not robust enough to draw definitive conclusions, especially in the long term, and further high-quality research (long-term randomized trials) is required to consolidate these early observations.

The cumulative survival rate of dental implants with micro-threads: a long-term retrospective study

PURPOSE

This study aimed to evaluate the long-term cumulative survival rate (CSR) of dental implants with micro-threads in the neck over a 10-year follow-up period and to examine the factors influencing the survival rate of dental implants.

METHODS

This retrospective study was based on radiographic and dental records. In total, 151 patients received 490 Oneplant® dental implants with an implant neck micro-thread design during 2006-2010 in the Department of Periodontology of Seoul National University Dental Hospital. Implant survival was evaluated using Kaplan-Meier analysis. Cox proportional hazard regression analysis was used to identify the factors influencing implant failure.

RESULTS

Ten out of 490 implants (2.04%) failed due to fixture fracture. The CSR of the implants was 97.9%, and no significant difference was observed in the CSR between external- and internal-implant types (98.2% and 97.6%, respectively, P=0.670). In Cox regression analysis, 2-stage surgery significantly increased the risk of implant failure (hazard ratio: 4.769, P=0.039). There were no significant differences in influencing factors, including sex, age, implant diameter, length, fixture type, location, surgical procedure, bone grafting, and restoration type.

CONCLUSIONS

Within the limitations of this retrospective study, the micro-thread design of the implant neck was found to be favorable for implant survival, with stable clinical outcomes.

Tissue-Level Laser-Lok Implants Placed with a Flapless Technique: A 4-Year Clinical Study

BACKGROUND

The present study aims to analyze the use of Laser-Lok microtextured neck implants placed with a transmucosal surgical approach. The marginal bone level (MBL) and periodontal parameters were evaluated in a cohort prospective 4-year clinical study.

METHODS

A total of 41 implants were placed in 36 healthy consecutive patients (16 males, 20 females, mean age 60 ± 9 years). Tapered tissue level implants, characterized by a 2.0 mm laser-microtextured neck, were used with a flapless approach. Customized abutments and provisional resin crowns were positioned. Definitive metal-ceramic crowns were cemented approximately 4 months after insertion. Periapical radiographs were taken after 1, 3, 6, 12, 36 and 48 months from implant placement to evaluate MBL. Gingival thickness (thin/thick), plaque score (PS) and bleeding on probing (BoP) were evaluated.

RESULTS

After 48 months, all implants were safe from complications. No complications, peri-implantitis, early implant failures or mucositis occurred. The survival rate was 100%. Mean MBL during the follow-up was -0.15 ± 0.18 at T1, -0.29 ± 0.29 at T3, -0.45 ± 0.37 at T6, -0.53 ± 0.45 at T12, -1.06 ± 1.13 at T 36 and -1.10 ± 0.89 at T 48. Implants placed 2-3 months after tooth extraction revealed lower MBL variation when compared to those placed immediately (in fresh extraction sockets) or in completely healed ridges (delayed group). Narrower diameter implants (3.8 mm) showed significantly higher MBL variation when compared to 4.6 diameter implants. Multilevel analysis at T48 revealed that among all the evaluated variables, implant diameter was the factor mostly associated with MBL modifications (p = 0.027).

CONCLUSION

This 4-year clinical study supports the use of Laser-Lok implants placed at tissue level with a flapless approach. A limited bone loss during the 48-month follow-up was observed. Periodontal parameters were stable with no sign of inflammation or soft tissue alteration. The use of Laser-Lok implants with transmucosal surgery represents a suitable technique with a minimally invasive approach.

Orthodontic pretreatment with aligners for optimizing the result prior to fixed restorations in the esthetic zone

OBJECTIVE

To show the benefit of a minor orthodontic pretreatment prior to fixed restorations in the esthetic zone in challenging situations.

OVERVIEW

Esthetic rehabilitations in complex situations need careful treatment planning and comprehensive interdisciplinary approach. Minor orthodontic pretreatments may transfer complex situations into straight forward situations. Typical indications are space opening in order to provide space for a restoration with anatomic proportion or corrections of the tooth axis.

CONCLUSION

This article presents three clinical cases that show how decision making can be facilitated by a functional and esthetic wax-up/mock-up workflow and how orthodontic pretreatment can contribute to a more functional, less invasive, and more esthetic outcome of restorative treatments in the esthetic zone.

CLINICAL SIGNIFICANCE

Some complex cases in restorative dentistry can be transformed to straight forward cases with the help of minor orthodontic tooth movements.

The effect of loading time on marginal bone change of implants immediately placed after extraction: a retrospective study

BACKGROUND

The purpose of this study is to compare and analyze the treatment outcomes between two groups which are both immediately placed implant cases, one is immediate loading, and the other is conventional loading group.

METHODS

Medical records of the patients who underwent implant treatment which were immediately placed after tooth extraction were analyzed. Demographic data were collected and by using periapical or panoramic radiographic image, marginal bone level and distant crestal bone level were measured. Marginal bone change over time was analyzed and compared between immediate loading group and conventional loading group.

RESULTS

A total of 71 patients, 112 immediately placed implants after tooth extraction were initially involved. Measuring was done with implants which had not failed (81). 10 implants were had failed and removed. The others were excluded because of follow-up loss, absence of radiographic image, etc. Demographic data were collected, and measured values were averaged at each follow-up and showed in linear graphs.

CONCLUSIONS

In case of immediate implantation of dental implant after extraction, loading time could affect marginal bone level or biological width of the implant. Immediate loading group showed 0.92 mm (mean value) more bone loss compared to conventional loading group at bone-implant contact points 24 months after implantation. At distant crestal points, there was no noticeable difference in bone change pattern between two groups.

Screw-Type Collar vs. Non-Screw-Type Collar Implants—Comparison of Initial Stability, Soft Tissue Adaptation, and Early Marginal Bone Loss—A Preclinical Study in the Dog

Simple Summary

Implant neck characteristics may affect initial implant stability, soft tissue healing, and early marginal bone loss (EMBL) at second-stage surgery. Screw-type rough-surface collar implants had statistically significant poorer soft tissue healing and increased marginal bone loss compared to non-screw type implants at the time of 2nd-stage surgery. The significance of the novel implant design results in preventing EMBL awaits further research.

Abstract

Background: Implant neck characteristics may affect initial implant stability, soft tissue healing, and early marginal bone loss (EMBL) at second-stage surgery. The null hypothesis was that, following two-stage implant insertion, rough surface, non-screw-type collar implants will present lower EMBL at 2nd-stage surgery than rough-surface, screw-type collar implants. Methods: The study comprised seven male beagle dogs (mean weight 10.57 ± 2.8 kg; range 9–17 kg). A novel implant design was developed, composed of 2 parts: an apical part resembling a regular threaded implant, and a coronal non-screw-type collar, 4.2 mm long, served as the study group, whereas standard threaded implants served as control. Twenty-eight implants were placed: two on each side of the mandible. All implants were sand-blasted/acid-etched and of similar dimensions. Each dog received four implants. To assess location (anterior vs. posterior) impact on the outcomes, implants were placed as follows: group I—posterior mandible right—non-screw-type collar implants; group II—anterior mandible right—similar non-screw-type collar implants. To assess the collar-design effect on the outcomes, implants were placed as follows—Group III—anterior mandible left—control group, screw-type collar implants; Group IV—study group, posterior mandible left—non-screw-type collar implants. The following parameters were measured and recorded: insertion torque, soft tissue healing, early implant failure, and EMBL at 2nd-stage surgery. Results: No statistically significant differences were noted between groups I and II regarding all outcome parameters. At the same time, although insertion torque (55 N/cm) and early implant failure (0) were similar between groups III and IV, group III presented significantly poorer soft tissue healing (1.43 vs. 0.14) and increased marginal bone loss (0.86 vs. 0 mm). Conclusions: When a two-stage implant protocol was used, rough-surface non-screw-type collar implants led to superior outcomes at 2nd-stage surgery. Implant location did not affect the results. The significance of this result in preventing EMBL awaits further research.

Effect of microthread design on the preservation of marginal bone around immediately placed implants: a 5-years prospective cohort study

Background

This study aimed to evaluate the effect of the microthread design at the implant neck on the preservation of marginal bone around immediately-placed implants in a 5-year follow up.

Methods

Thirty patients received 41 immediately placed implants which were randomly assigned to treatment groups with microthreaded implants (test group, n = 22) or threaded implants (control group, n = 19). Clinical and radiographic analyses were carried out after 1 and5 years. Plaque index, bleeding on probing, suppuration, probing depth and marginal bone loss were subject to evaluations. The results were analyzed with the T-test, Fisher’s exact test and Mann–Whitney U test.

Results

No implants failed; thirty-five implants (in 27 patients); 21 microthreaded and 14 threaded implants; completed the 5 year follow up. The mean values of the marginal bone loss in microthreaded and threaded groups were 1.12 ± 0.95 mm and 0.87 ± 0.78 mm, respectively during an observation period of 70.9 ± 10.4 months; the differences in marginal bone loss and other pre-implant parameters were not significant between groups (P > 0.05).

Conclusion

Both implant designs showed acceptable results in terms of the clinical parameters and marginal bone level. Within the limitation of this study, the results did not demonstrate any superiority of the microthread design compared to threaded one in marginal bone preservation around immediately placed implants over 5 years of loading.

In-Vitro Investigation of Fatigue and Fracture Behavior of Transmucosal versus Submerged Bone Level Implants Used in Fixed Prosthesis

Background: The present in vitro study aimed to investigate the fatigue performance of different dental fixtures in two different emergence profiles. Biological failures are frequently reported because the problem canonly be solved by replacing a failing implant with a new one. Clinicians addressed minor mechanical failures, such as bending, loosening or the fracture of screws, abutment, or the entire prosthesis, by simply replacing or fixing them. Methods: Transmucosal and submerged bone-level dental implants underwent fatigue strength tests (statical and dynamical performance) by a standardized test: UNI EN ISO 14801:2016. Two types of emergence profiles (Premium sub-crestal straight implant with a cylindrical-shaped coronal emergence or Prama one-piece cylindrical-shape implant with transmucosal convergent neck and hyperbolic geometry) were tested, and dynamic fatigue were run to failure. Data was analyzed by a suitable statistical tool. Results: The Wöhler curve of 0.38 cm Premium group c2, appeared to be significantly different from that of the 0.38 cm Prama group c3 (nonparametric one-way ANOVA χ2 = 6; degree of freedom = 1; probability = 0.0043) but not from that of the 0.33 cm Premium group c1 (nonparametric one-way ANOVA χ2 = 0.62; degree of freedom = 1; probability = 0.4328). Fatigue performance of configuration 2 was one and a half times better than that of configuration 3. Group c3 had a better ultimate failure load (421.6 ± 12.5 N) than the other two settings i.e., c1 (324.5 ± 5.5 N) and c2 (396.3 ± 5.6) reaching almost a nonsignificant level. Conclusions: It was observed that a transmucosal implant design could provide the highest resistance to static fracture. On the other hand, an equicrestal implant design could increase dynamic endurance.

Marginal Bone Loss around Machined Smooth Neck Implants Compared to Rough Threaded Neck Implants: A Systematic Review and Meta-Analysis

PURPOSE

The purpose of this meta-analysis was to assess the effect of rough threaded neck implants on marginal bone loss, compared to machined smooth neck implants.

MATERIALS AND METHODS

Literature searches were performed in the Cochrane Central Register of Controlled Trials (The Cochrane Library) (up to March 04, 2020), MEDLINE (PubMed) (1966 to March 04, 2020), and EMBASE (1980 to March 04, 2020), and reference lists of relevant manuscripts and relevant systematic reviews. Grey literature was sought using Grey Literature Net-Work Service (www.opengrey.eu) and The Grey Literature Report (www.greylit.org). Randomized controlled trials and controlled clinical trials that compared the effects of machined smooth neck implants versus rough threaded neck implants on marginal bone loss were included. Two review authors selected studies, assessed trial quality, and extracted data from included studies independently. The meta-analysis was carried out with Review Manager v5.3 software that compared marginal bone loss between rough threaded neck implants and machined smooth neck implants.

RESULTS

This review included 8 manuscripts (2 randomized controlled trials and 6 controlled clinical trials) from 6 clinical studies. The marginal bone loss around the rough threaded neck implants was significantly less than that around machined smooth neck ones (MD: -0.43 mm, 95% CI: -0.65 to -0.22 mm; p < 0.0001). In the subgroup with different platform connections, less marginal bone loss was observed around the rough threaded neck implants with platform switching (MD: -0.67 mm, 95% CI: -0.87 to -0.48 mm; p < 0.00001) or with regular platform (MD: -0.28 mm, 95% CI: -0.39 to -0.18 mm; p < 0.00001). The statistical analysis of the subgroups with functional loading for 3 or 6 months (MD: -0.39 mm; 95% CI: -0.61 to -0.18 mm; p = 0.0003) and 1 year or longer (MD: -0.43 mm, 95% CI: -0.65 to -0.22 mm; p < 0.0001) suggested that the rough threaded neck implants helped to reduce marginal bone loss.

CONCLUSIONS

The results of this review suggested that rough threaded neck implants may be helpful in maintaining the amount of marginal bone around implants. Larger sample size, longer follow-up periods and well-conducted randomized controlled trials are necessary to further prove the validity of the findings.

Maryland-bridge application as a suitable technique to preserve marginal bone level of not-submerged supracrestal implants

BACKGROUND

One to 6 months after implant placement is a critical time/period responsible for crestal bone loss that may affect implant osseointegration. The study aims to explore the effectiveness of provisional adhesive Maryland-bridge (AMB) applied to prevent marginal bone level (MBL) around implants placed in edentulous crestal bone in posterior area during osseointegration period.

METHODS

Healthy, non-smoker patients (N.=18) were included in the study. Titanium implants were placed nonsubmerged (i.e. tissue-level) with cover screws at gingival level in edentulous crestal bone with flapless technique. Nine patients randomly received an AMB, while 9 patients did not receive any AMB. Each AMB remained in place for 3 months and removed before impression. After 3 months abutments were applied, and provisional resin crowns cemented and definitive metal-ceramic crowns were cemented after 2-3 months. Periapical Rx were taken using paralleling technique before and after implant insertion, at 1, 3 months (pre-loading time) and after 6 months (post-loading time). MBL was evaluated in double-blind on scanned periapical radiographs and assessed at mesial and distal side of implants (M-MBL and D-MBL). Area of bone loss on mesial and distal side of implants (Area-M and Area-D) and Cervical Enamel Junction migration of mesial and distal adjacent teeth were also measured (CEJ-M and CEJ-D). Linear regression models were fitted to evaluate the existence of any significant difference.

RESULTS

Two drop-out was observed in AMB group. A total of 16 patients completed the study. After 6 months, all implants were safe and free from complications. AMB group showed the most stable MBL at 1-6 months, statistically different from non-AMB and resulted in a reduced crestal bone loss from baseline compared to Non AMB group. Area-M and Area-D were not statistically different between the groups. CEJ-M and CEJ-D were stable in both groups.

CONCLUSIONS

The use of Adhesive Maryland Bridge to protect non-submerged post-extractive implants is a safe procedure that prevents bone loss around implants and preserve the 3D architecture of crestal bone ridge.

Reliability of the Resonance Frequency Analysis Values in New Prototype Transepithelial Abutments: A Prospective Clinical Study

Resonance frequency analysis (RFA) requires abutment disconnection to monitor implant stability. To overcome this limitation, an experimental transepithelial abutment was designed to allow a SmartPeg to be screwed onto it, in order to determine the prototype abutments repeatability and reproducibility using Osstell ISQ and to assess whether implant length and diameter have an influence on the reliability of these measurements. RFA was conducted with a SmartPeg screwed directly into the implant and onto experimental abutments of different heights of 2, 3.5 and 5 mm. A total of 32 patients (116 implants) were tested. RFA measurements were taken twice for each group from mesial, distal, buccal and palatal/lingual surfaces. Mean values and SD were calculated and Intraclass Correlation Coefficients (ICC) (p < 0.05, IC 95%). The implant stability quotient (ISQ) mean values were 72.581 measured directly to implant and 72.899 (2 mm), 72.391 (3.5 mm) and 71.458 (5 mm) measured from the prototypes. ICC between measurements made directly to implant and through 2-, 3.5- and 5-mm abutments were 0.908, 0.919 and 0.939, respectively. RFA values registered through the experimental transepithelial abutments achieved a high reliability. Neither the implant length nor the diameter had any influence on the measurements' reliability.

A Non-Interventional Study Documenting Use and Success of Tissue Level Implants

Numerous randomised controlled multicentric studies have investigated various responses to different treatment modalities with dental implants. These studies do not always show the results of daily practice as they are performed under controlled and strict clinical conditions. This multicentric, non-interventionist trial aimed to document the behaviour of implants when used in daily dental practice, without inclusion or exclusion criteria. One hundred and ninety-six screw-shaped, tissue-level implants were placed, and each clinician decided which implant, surgical loading and prosthetic protocol to use. At surgery, data related to the implants were recorded. Additionally, the crestal bone level changes were evaluated for up to two years of follow-up. Two implants were lost before they were loaded. The success rate was 98.31%, and the survival rate was 98.79%. The implant stability quotient (ISQ) at surgery was 68.61 ± 10.35 and at 2 years was 74.39 ± 9.64. The crestal–shoulder distances were 1.25 ± 1.09 mm and 1.68 ± 1.07 mm in the mesial and distal aspects on the day of surgery, respectively, and 2.04 ± 0.91 and 2.16 ± 0.99 mm at 2 years, respectively. At 2 years, 69.3% of the patients were highly satisfied. The use of implants under standard conditions seemed to have success rates similar to their placement in controlled studies.

Clinical and radiographics results at 3 years of RCT with split-mouth design of submerged vs. nonsubmerged single laser-microgrooved implants in posterior areas

Aim

To evaluate and compare radiographic crestal bone loss (CBL) and soft tissue parameters around submerged/two-stage and nonsubmerged/one-stage single implants with the same endosseous portion (body design and surface, thread design and distance) and identical intramucosal laser-microgrooved surface, after 3 years of loading.

Materials and methods

Twenty submerged/two-stage implants and 20 nonsubmerged/one-stage implants were placed randomly with a split-mouth design in the posterior areas of 20 partially edentulous patients.

Radiographic and clinical examinations were carried out at the implant placement, at the delivery of prosthetic restorations, and at each year of the follow-up period. Plaque index (PI), probing depth (PD), bleeding on probing (BOP), and gingival recession (REC) were recorded. Radiographic crestal bone levels were assessed at the mesial and distal aspect of the implant sites. In addition, the influence of the vertical keratinized tissue thickness (KTT) on CBL was investigated.

Results

At the delivery of prosthetic restorations, a statistically significant difference (P = 0.013) was found in radiographic mean CBL between submerged and nonsubmerged implants (0.15 ± 0.05 mm vs. 0.11 ± 0.04 mm). At the end of the follow-up period, no statistical difference (P = 0.741) was found in the mean CBL between submerged and nonsubmerged implants (0.27 ± 04 mm vs. 0.26 ± 0.5 mm). The changes in the soft tissues including PI, PD, BOP, and REC had no significant differences in either group. Moreover, KTT did not show a statistical correlation with CBL.

Conclusions

After 3 years of loading, no statistical difference was noted in CBL and soft tissue conditions between single submerged two-stage and nonsubmerged one-stage laser-microgrooved implants.

Trial registration

http://clinicaltrials.gov/ct2/show/NCT03674762

Evaluation of crestal bone resorption around cylindrical and conical implants following 6 months of loading: A randomized clinical trial

OBJECTIVE

The purpose of this clinical study was to evaluate the effect of implant body form (cylindrical and conical implants) on crestal bone levels during 6 months' follow-up after loading.

MATERIALS AND METHODS

A total of 32 SPI implants (19 conical implants/13 cylindrical implants) were randomly placed in 12 male patients using a submerged approach. None of the patients had compromising medical conditions or parafunctional habits. Periapical radiographs using the parallel technique were taken after clinical loading and 6 months later. Clinical indices including pocket depth and bleeding on probing (BOP) were recorded on 6-month follow-up. Data were analyzed by independent samples t-test and Chi-square test with a significance level of 0.05.

RESULTS

Six months after loading, crestal bone loss was 0.84 (±0.29) mm around the cylindrical implants and 0.73 (±0.62) mm around the conical types, which was not significantly different (P = 0.54). Pocket depth around the cylindrical and conical implants was 2.61 (±0.45) mm and 2.36 (±0.44) mm, respectively (P = 0.13). BOP was observed among 53.8% and 47.4% of the cylindrical implants and conical (P = 0.13). Bone loss and pocket depth in the maxilla and mandible had no significant difference (P = 0.46 and P = 0.09, respectively).

CONCLUSION

In this study, although bone loss and clinical parameters were slightly higher in the cylindrical implants, there was no significant difference between the conical- and cylindrical-shaped implants.

Early and late implant failure of submerged versus non-submerged implant healing: A systematic review, meta-analysis and trial sequential analysis

INTRODUCTION

The aim of this systematic review was to analyse current evidence regarding differences in early and late implant failure as well as in marginal bone level (MBL) changes between submerged and non-submerged healed dental implants.

METHODS

PUBMED, SCOPUS, EMBASE and Web of Science databases were searched for prospective randomized and non-randomized controlled studies addressing direct comparison between submerged and non-submerged implant healing, without performing immediate loading. Early and late implant failure (before or after 6 months from implant placement, respectively) together with MBL were the investigated outcomes. Risk of bias assessment was performed using the Cochrane Collaboration Tool for Randomized clinical trials. Meta-analysis was performed and the power of the meta-analytic findings determined by trial sequential analysis (TSA).

RESULTS

Eleven studies met the inclusion criteria and were included in the review. Results of this systematic review revealed a small higher rate (2%) of early implant failure when a non-submerged healing approach is performed. Late implant failure appears not to be different in submerged or non-submerged healing, but the power of evidence, as determined by TSA, is not high. If we consider MBL changes at 1 year from implant load, it seems that non-submerged healing may better preserve marginal bone, although with a small effect size (0.13 mm).

CONCLUSIONS

Implants placed with a non-submerged technique have a higher risk (2%) of early failure. The power of the evidence about the effects on MBL is low, but present results seem to favour non-submerged healing, although with a very small effect size.

Peri-implant marginal bone loss rate pre- and post-loading: An exploratory analysis of associated factors

OBJECTIVES

To perform an exploratory analysis of factors influencing annual rates of peri-implant marginal bone loss (RBL) calculated over different time frames, at implants unaffected by peri-implantitis.

MATERIAL AND METHODS

A total of 154 implants from 86 patients were reviewed at 1.6-6.8 years after placement. Marginal bone levels (MBL) were assessed on intraoral radiographs at three time-points: immediately post-placement, time of loading, and least 1-year post-loading. RBLs (mm/year) were computed using these three time frames and corresponding MBL changes as: RBL placement-loading, RBL loading-review, RBL placement-review. Exploratory ordination of three RBLs, corresponding time durations, and 17 background factors were used for visualization. Hierarchical linear mixed-effects models (MEM) with predictor selection were applied to RBL outcomes. The correlation of actual MBL with MBLs predicted by RBL placement-loading and RBL loading-review was tested.

RESULTS

Median RBL placement-loading was 0.9 mm/year (IQR = 2.02), loading-review was 0.06 mm/year (IQR = 0.16), and overall RBL placement-review was 0.21 mm/year (IQR = 0.33). Among-patient variance was highest for RBL placement-loading (SD = 0.66). Longer time predicted lower RBL in all time frames. Shorter time of loading significantly predicted lower RBL placement-review. Augmentation predicted lower RBL placement-loading, while anterior location and older age predicted lower RBLs placement-loading placement-review. Only MBL projected using RBL placement-loading significantly correlated with actual MBL.

CONCLUSIONS

Exploratory analysis indicated RBL varied with the time duration used for calculation in pre- and post-loading, and overall periods. In each period, RBL declined with increasing time. Earlier loading predicted lower overall RBL. Higher pre-loading RBL predicted worse actual bone level.

Titanium dental implants with different collar design and surface modifications: A systematic review on survival rates and marginal bone levels

AIM

The aim of this study was to compare clinical and radiographic outcomes of dental implants with different neck characteristics.

METHODS

A protocol-oriented search aimed at the question: "In patients subjected to tooth replacement with screw-type dental implants does the modification of the implant neck macro- or microgeometry contribute to the improvement of survival rates and maintenance of the peri-implant marginal bone levels?" Primary outcomes were survival and marginal bone level (MBL) changes evaluated on randomized controlled trials with >10 participants and follow-up >1 year. Risk of bias was evaluated using the Cochrane Collaboration's tool. The review follows the PRISMA statement.

RESULTS

Forty-three studies compared: (a) One- versus two-piece implants (N = 7); (b) Two-piece implants with different neck characteristics (machined and rough collars, microthreads, LASER microtexturing) (N = 21); (c) Two-piece implants with macrogeometry modifications (tapering, back-tapering, and scalloping) (N = 6). One- and two-piece implants showed similar survival (RR = 0.45, 95% CI: [0.12, 1.66], p = 0.23) and MBL changes (WMD = 0.09 mm, 95% CI: [-0.27, 0.45], p = 0.64) at 1-year post-loading. Machined collar implants have higher risk of early failure than rough collar implants (RR = 3.96, 95% CI: [1.12, 13.93], p = 0.03) and 0.43 mm higher bone resorption (95% CI: [0.0, 0.86], p = 0.05). Microthreads (WMD = 0.07 mm, 95% CI: [-0.01, 0.15], p = 0.10) and LASER microtexturing (WMD = 0.15 mm, 95% CI: [-0.35, 0.65], p = 0.56) do not reduce bone resorption. Scalloped implants have 1.26 mm higher resorption (95% CI: [0.72, 2.00], p < 0.001).

CONCLUSIONS

One- and two-piece implants have similar survival and MBL changes. Rough collar implants have lower MBL changes than machined collar implants. Additional modifications to rough collars are irrelevant.

Immediate Early and Delayed Implants: A 2-Year Prospective Cohort Study of 131 Transmucosal Flapless Implants Placed in Sites With Different Pre-extractive Endodontic Infections

INTRODUCTION

To evaluate clinical outcome of early, immediate, and delayed transmucosal implants placed in patients affected by acute/chronic endodontic lesions.

MATERIALS AND METHODS

Eighty-five consecutive patients received 131 titanium implants with zirconium-oxide blasted surface. Pre-extractive diagnosis represented the main criteria for implant placement timing, following "best treatment" criteria. Implants were placed with flapless transmucosal technique. Hopeless teeth with chronic periapical lesions received atraumatic extraction, and an implant was immediately placed (Immediate Group, n = 29). Teeth with acute periapical lesion/abscess were extracted and implants placed after 8 to 12 weeks (Early Group, n = 29). Implants placed 10- to 12-month after extraction constituted the control group (delayed group, n = 73). Implants were loaded 3 months after insertion with provisional resin crowns and after approximately 15 days with definitive ceramic crowns. Marginal bone loss (MBL) was measured in a single-blind manner on periapical radiographs at 1, 3, 6, 12, and 24 months.

RESULTS

Multilevel analysis described exploring factors associated with MBL. Survival rate was 100%. MBL after 24 months was 0.78 ± 0.70 (95% confidence interval [CI]: 0.20 to -1.37) at immediate, 0.48 ± 0.70 at early (95% CI: -0.006 to -0.961), and 1.02 ± 1.01 (95% CI: 0.61 to -1.43) at delayed groups. Implant groups (immediate/early/delayed) and location (maxillary/mandibular) showed statistically significant results. Early group showed the lowest MBL values. The immediate group demonstrated less MBL than the delayed group.

CONCLUSION

Early implant placement technique preserves periimplant marginal bone level more than immediate and delayed techniques.

Recent advances in dental implants

Dental implants are a common treatment for the loss of teeth. This paper summarizes current knowledge on implant surfaces, immediate loading versus conventional loading, short implants, sinus lifting, and custom implants using three-dimensional printing. Most of the implant surface modifications showed good osseointegration results. Regarding biomolecular coatings, which have been recently developed and studied, good results were observed in animal experiments. Immediate loading had similar clinical outcomes compared to conventional loading and can be used as a successful treatment because it has the advantage of reducing treatment times and providing early function and aesthetics. Short implants showed similar clinical outcomes compared to standard implants. A variety of sinus augmentation techniques, grafting materials, and alternative techniques, such as tilted implants, zygomatic implants, and short implants, can be used. With the development of new technologies in three-dimension and computer-aided design/computer-aided manufacturing (CAD/CAM) customized implants can be used as an alternative to conventional implant designs. However, there are limitations due to the lack of long-term studies or clinical studies. A long-term clinical trial and a more predictive study are needed.

Comparison of Clinical, Radiographic, and Immunologic Inflammatory Parameters around Crestally and Subcrestally Placed Dental Implants: 5-Year Retrospective Results

PURPOSE

To compare changes in clinical (bleeding on probing [BOP] and probing pocket depth [PPD]), radiographic (crestal bone loss [CBL]), and immunologic inflammatory (interleukin-1beta [IL-1β] and matrix metalloproteinase-9 [MMP-9]) parameters around crestally and subcrestally placed dental implants 5 years after implant placement.

MATERIALS AND METHODS

Fifty-two patients were divided into 2 groups: group 1 (n = 27): patients with single implants placed approximately 2 mm below the alveolar crest; group 2 (n = 25): patients with single implants placed at bone level. In both groups, peri-implant BOP, PPD, and CBL were measured, and levels of IL-1β and MMP-9 were determined in duplicates using enzyme-linked immunosorbent assay. Full-mouth debridement was performed biannually in both groups. Statistical analysis was performed using the Mann-Whitney U test (significance set at p < 0.05).

RESULTS

All measurements in groups 1 and 2 were performed 5.3 ± 0.2 and 5.2 ± 0.1 years after implant placement, respectively. The mean CBL was 1.2 ± 0.2 mm and 1.4 ± 0.2 mm in groups 1 and 2, respectively. There was no significant difference in mean BOP, PPD, CBL and in levels of IL-1β, and MMP-9 among implants in both groups.

CONCLUSION

Clinical, radiographic, and immunologic inflammatory parameters are comparable around crestally and subcrestally placed single dental implants up to 5 years after placement. The depth of implant placement appears to have no effect on clinical status and performance of single dental implants.

Risk Factors for Peri-Implantitis: Effect of History of Periodontal Disease and Smoking Habits. A Systematic Review and Meta-Analysis

Objectives

The purpose of this review was to evaluate whether history of periodontitis and smoking habits could represent a risk factor for peri-implantitis and implant loss.

Material and Methods

This systematic review followed PRISMA guidelines and was registered at the PROSPERO database [registration numbers CRD42016034160 (effect of history of periodontitis) and CRD42016033676 (effect of smoking)]. Broad electronic (MEDLINE) and manual searches were conducted among articles published from January 1^st 1990 up to December 31^st 2015, resulting in 49332 records for history of periodontitis and 3199 for smoking habits. Selection criteria included prospective studies comparing two cohorts of patients, with and without the investigated risk factor, with a minimum follow-up period of three years, and reporting data on peri-implantitis and implant loss occurrence. Considering that only prospective studies were included, dichotomous data were expressed as risk ratios and 95% confidence intervals.

Results

Three studies evaluating history of periodontitis (on which quantitative analysis was performed) and one study on smoking effect were included. Both implant and patient-based meta-analyses revealed a significantly higher risk of developing peri-implantitis in patients with a history of periodontitis compared with periodontally healthy subjects, but not a statistically significant increased risk for implant loss.

Conclusions

The outcomes of this systematic review indicate history of periodontitis as a possible risk factor for peri-implantitis, while insufficient data are present in literature to evaluate the role of smoking. However, available evidence is still weak and immature, and sound epidemiological studies are needed to analyse the specific contribution of these potential risk factors.

Four-unit fixed dental prostheses replacing the maxillary incisors supported by two narrow-diameter implants - a five-year case series

OBJECTIVES

(1) To determine the survival rate of 10 four-unit fixed dental prostheses (FDPs) replacing the four maxillary incisors, supported by 20 narrow-diameter implants (NDIs), (2) to assess the incidence of mechanical and biological complications, and (3) to evaluate bone level changes longitudinally after final FDP insertion.

MATERIALS AND METHODS

Ten patients (six women, four men), mean age 49.4 ± 12.6 years, were treated with a four-unit anterior maxillary FDP (six screw-retained; four cemented). Biological parameters, eventual technical complications, radiographic measurements, and study casts were assessed at 1 (baseline), 3, and 5 years after implant placement. A multilevel logistic regression test was performed on clinical parameters and bone level changes (significance level P < 0.05).

RESULTS

The 5-year implant and FDP survival rate was 100%. Mean modified plaque index (mPI) values were 0.03 and 0.02 at 3 and 5 years, significantly lower when compared to mPI (0.11 ± 0.31) at 1 year. Mean modified sulcus bleeding index (mSBI) was 0.08, 0.08, and 0.15 over time. Probing depth (PD) values were 1.57, 1.64, and 2.03 mm. Statistically significant differences were found between 1 vs. 5 year (P = 0.0003) and 3 vs. 5 year (P = 0.001). Keratinized mucosa (3.65 mm) remained stable during observation period. DIB mean values were 2.01 ± 0.34, 2.13 ± 0.13, and 2.17 ± 0.38 mm. Patient satisfaction based on visual analog scale revealed favorable fulfillment of overall treatment and esthetic expectations.

CONCLUSIONS

Two NDIs supporting a four-unit FDP to replace the four missing maxillary incisors may be considered a predictable treatment modality.

Detection of five potentially periodontal pathogenic bacteria in peri-implant disease: A comparison of PCR and real-time PCR

The aim of this study was to compare the microbial analysis methods of polymerase chain reaction (PCR) and real-time PCR (RT-PCR) in terms of detection of five selected potentially periodontal pathogenic bacteria in peri-implant disease. Therefore 45 samples of healthy, mucositis and peri-implantitis (n = 15 each) were assessed according to presence of the following bacteria using PCR (DNA-strip technology) and RT-PCR (fluorescent dye SYBR green-system): Aggregatibacter actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Treponema denticola (Td), Tanerella forsythia (Tf), and Fusobacterium nucleatum (Fn). There were no significant correlations between the bacterial and disease patterns, so the benefit of using microbiological tests for the diagnosis of peri-implant diseases is questionable. Correlations between the methods were highest for Tf (Kendall's Tau: 0.65, Spearman: 0.78), Fn (0.49, 0.61) and Td (0.49, 0.59). For Aa (0.38, 0.42) and Pg (0.04, 0.04), lower correlation values were detected. Accordingly, conventional semi-quantitative PCR seems to be sufficient for analyzing potentially periodontal pathogenic bacterial species.

Clinical efficacy of immediate implant loading protocols compared to conventional loading depending on the type of the restoration: a systematic review

BACKGROUND AND OBJECTIVES

Immediate loading has become a predictable option to restore all clinical situations. The aim of this systematic review was to assess whether immediate loading protocols achieve comparable clinical outcomes when compared to conventional loading protocols depending on the type of prosthetic restoration.

METHODS

A protocol was developed aimed to answer the following focused question: "What are the effects of immediate implant loading protocols compared to conventional implant loading, in terms of implant failure, marginal bone levels, and biological and mechanical complications based on the type of restoration?" The next subanalysis were performed as follows: the extent, type, and material of the restoration and the type of occlusal contact in function. This systematic review only included randomized controlled trials (RCTs) with a follow-up of at least 6 months after implant loading.

RESULTS

Thirty-seven final papers were included. The results from the meta-analyses have shown that the immediately loading implants demonstrated a statistically significant higher risk of implant failure [RR = 1.92; 95% CI (1.04; 3.54); P = 0.036], a statistically significant lower bone loss [WMD = 0.046; 95% CI (0.043; 0.049); P = 0.000] and a smaller increase in ISQ values [WMD = -1.096; 95% CI (-1.615; -0.577); P < 0.001, although both groups attained high survival rates (98.2% in the test and 99.6% in the control). Single teeth implants were greater risk of failure, when compared to immediately loaded full arch restorations (RR = 2 vs. 0.9), so as the occlusal pattern when compared to non-occlusal (RR = 1.9 vs. 1.4).

CONCLUSIONS

Immediate loading may impose a greater risk for implant failure when compared to conventional loading, although the survival rates were high for both groups.