Platform-switching implants and bone preservation: a systematic review and meta-analysis

Immediate Implant Therapy with Full-Digital Workflow to Replace a Central Incisor

Background: Replacing a maxillary central incisor and immediately placing an implant represents a clinical challenge. Methods: This case report demonstrates a full digital workflow to achieve a predictable implant placement and esthetically pleasing restoration for a 35-year-old male patient who suffered a horizontal root fracture after a sports accident. The patient's treatment included digital implant planning, minimally traumatic tooth extraction, computer-guided implant placement, soft tissue augmentation, and a provisional restoration to contour the augmented gingival tissues. The process began with cone beam computed tomography (CBCT) evaluation and patient consultation on treatment options, with the patient opting for implant therapy. Using a 3D-printed surgical guide, the implant was placed precisely, and a soft tissue graft was used to enhance the gingival architecture and volume. A provisional restoration was designed to support the emergence profile and condition the peri implant soft tissues. A final digital impression was made, and a screw-retained all-ceramic crown was fabricated uneventfully after healing. Results: This digital approach allowed accurate planning and allowed the efficient execution of a technique-sensitive procedure such as immediate implant placement, thus providing an esthetic and functional solution while minimizing treatment time. Conclusions: The case highlights that immediate implant therapy in the esthetic zone requires meticulous planning and execution, and that incorporating advanced digital tools and techniques is required to achieve favorable clinical outcomes.

The Effect of Prosthetic Factors on the Long-Term Survival of Dental Implants: A Narrative Review

The success of implants depends on the biological and mechanical factors of the implant, as well as on the chosen prosthesis, which has different characteristics that can affect the survival of the implant and its marginal bone levels. Therefore, when choosing the type of prosthesis, it is necessary to understand and consider each of these variables and tailor them to the relevant clinical situation. In this narrative review, we will assess the types of prostheses, their different characteristics, timing, and their impact on implant survival and marginal bone levels, as accepted in today's literature.

Mucoadhesive delivery systems for oral candidiasis treatment: A systematic review and meta-analysis

OBJECTIVES

This systematic review and meta-analysis aimed to evaluate the clinical and mycological effectiveness of mucoadhesives as vehicles for drugs or natural products in the treatment of oral candidiasis.

MATERIALS AND METHODS

The search for articles was carried out in the Medline/PubMed, SCOPUS, EMBASE, Web of Science, Cochrane Library, and SciELO databases before August 2023. We selected the studies, extracted the data, evaluated the study quality, graded the evidence, performed the risk of bias, and carried out meta-analysis.

RESULTS

A total of 389 potentially relevant articles were identified, and 11 studies (1869 participants) met the inclusion criteria of the systematic review. The overall risk of bias was considered low. The most common presentation of mucoadhesives was tablets, with miconazole being the most frequently drug used in the delivery system. Mucoadhesives demonstrated comparable efficacy with topical or systemic antifungal agents, with no significant differences between treatments in terms of clinical (RR = 0.907; 95CI = 0.3-1.297; p = 0.591; I2 = 64.648) or mycological (RR = 0.95; 95CI = 0.667-1.360; p = 0.789; I2 = 73.271) efficacy.

CONCLUSIONS

Mucoadhesives may be a suitable alternative to conventional treatments, with the advantage of reducing the frequency of application by up to 5 times and the daily dosage by up to 20 times.

Analysis of 8.5 mm Long Dental Implants Provided with Splinted or Solitary Implant Restorations: A 15-Year Prospective Study

Background/Objectives: The long-term effects of implant properties, such as implant length, platform switch, and crown splinting, on peri-implant health require more investigation. Therefore, the aim was to assess the long-term peri-implant health and patient satisfaction in a patient cohort, obtained from two prospective randomized controlled trials, who received 8.5 mm long dental implants, with either splinted or solitary suprastructures and with or without a platform switch, over a period of 15 years. Methods: One hundred and twenty-two patients received either one or two 8.5 mm long dental implants (223 dental implants) with and without platform switch, restored with either a solitary (n = 89) or a splinted (n = 134) restoration in the posterior region. Clinical and radiographical parameters and patient satisfaction were prospectively recorded at 1 month, and 1, 5, and 15 years after the placement of the restoration. Patient satisfaction was recorded with a self-administered questionnaire using a 5-point scale and a visual analog scale (0-10). Results: Eighty-one patients with one hundred and fifty-four implants were assessed after a 15-year follow-up. The clinical parameters were low and comparable between the implant types (OsseoTite XP Certain, OsseoTite XP Certain Prevail, NanoTite XP Certain, NanoTite XP Certain Prevail, PalmBeach Gardens, FL, USA) over time. The implants that incorporated a platform switch showed significantly less bone loss than the implants without a platform switch (-0.37 mm, 95% CI -0.69 to -0.05 mm, p = 0.024 and β = -0.47, 95% CI -0.80 to -0.14, p = 0.006). The implants with splinted restorations experienced more bone loss over time compared to the implants with solitary restorations (0.39 mm, 95% CI 0.15-0.63, p = 0.002). Patient satisfaction was high after 15 years. Conclusions: All the tested dental implants with 8.5 mm length provide satisfactory 15-year results with regard to the clinical and radiographical parameters as well as patient satisfaction. The platform-matched implants were associated with more bone loss compared to the platform-switched implants, and the implants with splinted crowns portrayed more bone loss than the solitary implant crowns.

Impact of Osteoporosis on Autogenous Bone Graft Resorption

BACKGROUND

Osteoporosis is a common disorder that is characterized by decreased bone density and increased bone resorption. This bone resorption may affect the grafted bone during the maxillofacial reconstruction.

PURPOSE

This study aimed to measure the association between osteoporosis and resorption of anterior iliac crest bone grafts used to reconstruct the atrophic anterior maxillae.

STUDY DESIGN, SETTING, SAMPLE

This prospective cohort study included female patients requiring bone augmentation of the anterior maxilla. Patients with a ridge width of <4 mm and ridge height of >7 mm were enrolled in the study. Exclusion criteria were chronic use of corticosteroids or intravenous bisphosphonates, history of maxillofacial radiation therapy, current smoking, and underlying conditions contributing to bone metabolism (eg, hyperparathyroidism, chronic renal failure, and hypophosphatemia).

PREDICTOR/EXPOSURE/INDEPENDENT VARIABLE

Osteoporosis status was a predictor variable. Patients were allocated to the osteoporosis or control group based on T-scores obtained by dual-energy x-ray absorptiometry. Mean T-scores ≤ -2.5 were assigned to the osteoporosis group.

MAIN OUTCOME VARIABLE(S)

The outcome variable was graft resorption, defined as the difference in ridge width between measurements made immediately (T1) and 6 months postoperatively (T2) using cone-beam computed tomography.

COVARIATES

Patient age, preoperative (T0) bone width, and the amount of bone augmentation, defined as the differences in ridge width between measurements made preoperatively (T0) and immediately after grafting (T1), were covariates of this study.

ANALYSES

Descriptive, analytic, and general linear models were computed. Statistical significance was set a P < .05.

RESULTS

Thirty-two patients were included in the study (15 in the osteoporosis group and 17 in the control group). The amount of graft resorption at 6 months after grafting was 2.57 ± 0.59 mm in the osteoporosis group and 0.97 ± 0.59 mm in the control group (P < .001). A significant correlation was found between the mean T-score and graft resorption 6 months after grafting (P < .001).

CONCLUSION AND RELEVANCE

A significant correlation was observed between osteoporosis and graft resorption in the anterior maxilla after 6 months.

Survey of screw-retained versus cement-retained implant restorations used in both education and private dental practices

AIMS

In the literature, it is still unclear if the decisions for selecting the type of implant crown-retaining system are based on scientific-based research or if the Universities' choices, Implant marketing trends, or finances could have a major influence on the private dentists' decisions.

OBJECTIVES

Therefore, this study aimed to evaluate the crown-retaining system (cement- or screw-retained) used in dental schools and private dental practices.

METHODS

A 13-item questionnaire was sent to Canadian dental schools (n = 10) and dental offices in London (n = 298), Canada. The questionnaire included demographic questions and questions to reveal the dentists' perspectives on prosthetic implant treatment between the two-retaining systems. Results were analyzed using descriptive statistics and multinomial logistic regression (p = 0.05).

RESULTS

Twenty-four private dentists and five dental schools responded to the survey - 62.5% of private practitioners and 60% of universities reported using both systems. A trend was observed in using screw-retained systems by dentists who graduated 5-10 years ago. Straumann, Astra, and Nobel Biocare were the private practices and dental schools' preferred implant systems. The use of platform switching for all cases was selected by 54.2% of the private practitioners and 40% of the dental schools. Resin cement was the private practice's preferred cementation method; the dental schools used glass ionomer and zinc phosphate cement. The multinomial logistic regressions showed no statistical difference between the crown-retaining system chosen and the decision factors. The laboratory technician's recommendations and cost influenced the decision-making process for private dentists. For the universities, perio-restorative outcome, implant position, survival rates, institute preferences, and evidence-based research influenced the crown-retaining system's decision-making process.  CONCLUSION: The Canadian dental schools and private practice reported using both screw- and cement-retaining systems. However, there was a difference in the selection criteria as the universities showed a tendency towards a more research-based approach in their decision, while for the private practices, the technicians' recommendations and cost played a major role in the decision process. It was noted that the implant systems preconized by the Universities were observed to be used in private practices.

Attachment systems for mandibular implant-supported overdentures: A systematic review and meta-analysis of randomized controlled trials

STATEMENT OF PROBLEM

Although mandibular implant-supported overdentures have been highly recommended as a treatment option, a consensus on the type of attachment systems that can be used to increase implant and prostheses survivability is lacking.

PURPOSE

The purpose of this systematic review and meta-analysis was to compare different types of attachments for retention by investigating outcome measures such as implant and prosthesis survival rates and biological and prosthesis complications in participants with a mandibular implant-supported overdenture.

MATERIAL AND METHODS

The search was performed in the PubMed, Cochrane, Embase, and Scopus databases by following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria and registered with the International Prospective Register of Systematic Reviews (CRD42021253566). An analysis of association was conducted between different attachment systems and implant and overdenture survival rates in randomized controlled clinical trials.

RESULTS

The initial search indicated 477 studies, of which 25 randomized controlled trials (RCTs) were included for analysis. A total of 2154 implants and 737 overdentures were analyzed in the meta-analysis. The main results indicated the failure rate for dental implants to be 2.0% (95% confidence interval [CI], 1.3 to 3.2) and overdentures 4.2% (95% CI, 1.6 to 10.5), respectively. With regard to different attachment systems, a similar failure rate was identified with bar-type retention (7.7% to 95% CI, 3.0 to 18.1), magnetic retention systems (7.6% to 95% CI, 2.2 to 22.7), and ball-type retention (6.8% to 95% CI, 3.0 to 14.3). No significant difference was found in biological complications for splinted and unsplinted implant overdentures (P=.902). Regarding prosthetic complications, the most favorable groups were LOCATOR attachments followed by telescopic and Conus, bar, and ball attachments. Magnet attachments had higher prosthetic complications (7.4 times) than the other attachments.

CONCLUSIONS

Implants and implant-supported mandibular overdentures showed a high survival rate irrespective of the attachment system used. Splinting implants did not significantly affect the rate of biological complications. Prosthetic complications were most common for magnet and least common for LOCATOR attachments.

The effect of one-time abutment placement on clinical and radiographic outcomes: A 5-year randomized clinical trial

OBJECTIVE

The aim of this study was to evaluate the long-term (5 years) clinical efficacy of the one-abutment one-time protocol (test) versus the standard of care by placing the definitive abutment on the day of the prosthetic delivery (control).

MATERIALS AND METHODS

In this study, 39 subjects with 60 implants were randomly allocated to either the test or the control group. Changes in the radiographic interproximal bone levels (DIB), modified sulcus bleeding index, probing depth, modified plaque index, papilla fill (Jemt score), incidence of peri-implantitis and peri-implant mucositis as well as patient-reported outcomes measures (PROMs) were collected and compared at 1, 3 and 5 years.

RESULTS

At 5 years, the control group showed a greater, although not statistically significant, change in mean DIB values (0.97 mm vs. 0.53 mm). Regarding the other clinical parameters evaluated, no statistically significant differences were observed between groups at any time point. At 5 years, 51% of the implants presented peri-implant mucositis (25.5% in the control and 23.5% in the test), and only one implant in the test group developed peri-implantitis.

CONCLUSIONS

The connection and disconnection of healing abutments during the healing period was not associated with higher long-term bone loss. Clinical outcomes and PROMs were similar between groups.

An introduction to dental implants

The use of implants to replace missing teeth is now commonplace and practised by clinicians worldwide in both general and specialist practice. There is an abundance of evidence on the general success of implant treatment. As well as reviewing the history of dental implants, this narrative review will discuss the merits and successful placement of tissue-level verses bone-level implants. Furthermore, the article will evaluate the concept and benefits of platform switching for implant treatment. Finally, with the increased placement of implants, this narrative paper will review how different titanium surfaces impact on the risk of peri-implantitis.

Efficacy of acellular xenogeneic dermal matrix graft in the treatment of multiple gingival recessions: systematic review and meta-analysis

OBJECTIVE

This study aimed to compare the efficacy of acellular xenogeneic dermal matrix graft (AXDM) compared to connective tissue graft (CTG) in treating multiple gingival recessions.

MATERIALS AND METHODS

A systematic search of electronic databases was conducted to identify randomized clinical trials (RCTs) that compared AXDM and CTG. The selected studies were subjected to bias risk assessment, data extraction, and meta-analyses. Parameters such as gingival recession height, width, mean percentage of root coverage, and complete root coverage were analyzed.

RESULTS

Seven RCTs involving 146 patients were included. The meta-analyses indicated that CTG was statistically superior to AXDM in reducing gingival recession height at the final follow-up (mean difference: -0.104 mm, 95% confidence interval [CI]: -0.180-0.028, p = 0.008) and width at the final follow-up (mean difference: -0.285 mm, 95% CI: -0.541-0.030, p = 0.029). CTG also demonstrated a significantly higher mean percentage of root coverage at the 6-month follow-up (difference in means: -2.761 mm, 95% CI: -4.932-0.590, p = 0.013) and a higher percentage of complete root coverage at the 6-month follow-up (odds Ratio [OR]: 0.598, 95% CI: 0.4-0.892, p = 0.012) compared to AXDM. However, there was no significant difference in the number of teeth with complete root coverage between CTG and AXDM (OR: 1.610, 95% CI: 0.983-2.636, p = 0.058) and aesthetic outcomes (mean difference: 0.148, 95% CI: -0.277-0.573, p = 0.494).

CONCLUSIONS

CTG is more effective than AXDM in treating multiple gingival recessions. This is evidenced by significant reductions in gingival recession height and width, a higher mean percentage of root coverage, and a greater percentage of complete root coverage at the 6-month follow-up.

CLINICAL RELEVANCE

In some clinical situations an alternative to CTG is required for the treatment of multiple gingival recessions. AXDM, despite presenting clinical outcomes that are not as satisfactory as CTG, can be used for this purpose.

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.

A systematic review and meta-analysis of the clinical performance of implant-supported overdentures retained by CAD-CAM bars

Currently, there is no consensus on the indications and clinical performance of implant-supported overdentures (IODs) involving computer-aided design and manufacturing (CAD-CAM) bars.

OBJECTIVE

To evaluate the performance of IODs involving CAD-CAM bars.

METHODOLOGY

A comprehensive search of studies published until May 2023 was conducted in many databases, including PubMed/MEDLINE, Web of Science, Cochrane Library, and SciELO, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). The population, intervention, comparison, outcome (PICO) question was: "How do IODs retained by bars fabricated by CAD-CAM technology perform in daily clinical practice?" The meta-analysis included clinical studies based on effect size and a two-tailed null test with a 95% confidence interval (CI).

RESULTS

Ten studies were included in the meta-analysis. Among them, nine reported a 100% implant survival rate for all CAD-CAM milled bars. Complications were reported in two studies with CAD/CAM-milled titanium bars, and one study reported more fractures in soldered gold bars used in maxillary rehabilitation. However, no fractures were observed in IODs retained by PEEK and zirconia bars. According to six studies, biological complications, including peri-implantitis, were minimal in the BioHPP and PEEK bar groups, while no cases were reported in the titanium or zirconia bar groups. CAD-CAM-milled zirconia bars had higher plaque and bleeding indices compared with titanium bars, as evidenced by findings from five studies. All four studies that evaluated Oral Health Impact Profile (OHIP) scores showed a positive effect of IODs retained by CAD-CAM milled titanium bars on quality of life. Patient satisfaction and acceptance by prosthodontists were significantly high, according to the results of five studies.

CONCLUSION

Overdentures retained with CAD-CAM milled titanium bars show great potential for use in daily clinical practice. Moreover, patient and practitioner satisfaction was very high when this method was used.

Changes in Peri-implant Marginal Bone Level by Jaw Location: A Systematic Review and Meta-Analysis of 4970 Implants

The purpose of this study was to evaluate the current evidence on marginal bone-level changes (ΔMBL) around internal connection implants with fixed prostheses by jaw location over time. An electronic literature search for ΔMBL (change in marginal bone level) was conducted in 6 databases. The data from the included manuscripts were categorized by jaw sextant of the implants and duration of follow-up (<2 years, 2-5 years, and >5 years). Meta-analyses were performed on groups with at least 5 studies. A total of 1270 records were screened. Full-text review of 413 papers resulted in a total of 46 studies (representing 2259 patients with 4970 implants) included for quantitative synthesis and analysis. The ΔMBL was summarized at 2 time intervals with the following results: <2 years (anterior maxilla = 0.393 mm [95% confidence interval {CI}, 0.172, 0.613], posterior maxilla = 0.468 mm [95% CI, 0.288, 0.648], and posterior mandible 0.559 mm [95% CI, 0.397, 0.72]), 2 to 5 years (anterior maxilla = 0.683 mm [95% CI, 0.224, 1.142], posterior maxilla = 0.645 mm [95% CI, 0.42, 0.87], and posterior mandible 0.563 mm [95% CI, 0.278, 0.849]). There were insufficient studies in the anterior mandible and with follow-up data over 5 years for quantitative synthesis. Within the limitations of this study, location within the maxillary and mandibular jaws does not seem to influence ΔMBL around internal connection bone level implants with fixed restorations. Although there may be a tendency for greater initial remodeling in the posterior mandible followed by long-term stability, additional studies are needed to evaluate this further.

Influence of Torque on Platform Deformity of the Tri-Channel Implant: Two- and Three-Dimensional Analysis Using Micro-Computed Tomography

Background and Objectives: The insertion of the dental implant in the bone is an essential step in prosthetic rehabilitation. The insertion torque has the potential to distort the prosthetic platform, which can cause future biomechanical problems with the continuous action of occlusal forces. The aim of this study is to evaluate different insertion torques in the deformation of tri-channel platform connections through two- and three-dimensional measurements with micro-CT. Materials and Methods: A total of 164 implants were divided into groups (platform diameter and type): 3.5, 3.75, and 4.3 mm NP (narrow platform), and 4.3 mm RP (regular platform). Each implant-platform group was then divided into four subgroups (n = 10) with different torques: T45 (45 Ncm), T80 (80 Ncm), T120 (120 Ncm), and T150 (150 Ncm). The implant-abutment-screw assemblies were scanned and the images obtained were analyzed. Results: A significant difference was observed for the linear and volume measures between the different platforms (p < 0.01) and the different implant insertion torques (p < 0.01). Qualitative analysis suggested a higher deformation resistance for the 3.75 NP compared to the 3.5 NP, and RP was more resistant compared to the NP. Conclusions: The 0.25 mm increment in the implant platform did not increase the resistance to the applied insertion torques; the 4.3 mm implant was significantly stronger compared to the 3.5 mm implant; and the proposed micro-CT analysis was considered valid for both the 2D and 3D analyses of micro-gaps, qualitatively and quantitatively.

Bone substitutes vs. autogenous bone graft for regeneration of the anterior maxillary alveolar process with horizontal bone resorption: systematic review

The objective of this systematic review was to identify the available scientific evidence on bone substitutes (BS) compared to autogenous bone grafts (ABG) for regeneration of horizontal bone resorption in the anterior maxillary alveolar process, aiming at rehabilitation with endosseous implants. This review was performed according to the PRISMA guidelines (2020) and registered in the database PROSPERO (CRD: 42017070574) . The databases searched were PUBMED/MEDLINE, EMBASE, SCOPUS, SCIENCE DIRECT, WEB OF SCIENCE, and CENTRAL COCHRANE, in the English language. The Australian National Health and Medical Research Council (NHMRC) and Cochrane Risk of Bias Tool were used to assess the study's quality and risk of bias. 544 papers were found. After the selection process, six studies were selected for review. A total of 182 patients were followed for a period of 6 to 48 months. The mean age of patients was 46.46 years, 152 implants were installed in the anterior region. Two studies achieved a reduced graft and implant failure rate, while the remaining four studies had no losses. It may be concluded that both the use of ABG and some BS are viable alternatives for the rehabilitation with implants in individuals with anterior horizontal bone loss. However, additional RCTs are warranted due to the limited number of papers.

Three-dimensional digital evaluation of tooth symmetry and volume in patients with missing and peg-shaped maxillary lateral incisors

INTRODUCTION

This study aimed to evaluate the 3-dimensional tooth crown symmetry and the crown volumes of maxillary and mandibular teeth in patients with unilateral or bilateral missing or peg-shaped maxillary lateral incisors.

METHODS

Six groups were established for the possible clinical variations in patients with unilateral missing or peg-shaped maxillary lateral incisors, bilateral presence of these tooth anomalies, and a control group (CG) with normal lateral incisors. The study was conducted on digital dental models of 132 patients. The morphologic symmetry of the antimere teeth was investigated using 3-dimensional deviation analysis. Volumes of contralateral teeth were compared within and among groups for the maxilla and mandible. Furthermore, volumes of teeth were compared in missing and peg-shaped quadrants and quadrants of CG. Intergroup differences were tested using one-way analysis of variance and Kruskal-Wallis tests, whereas paired t and Wilcoxon tests were used for parametric and nonparametric variables, respectively, for intragroup comparisons.

RESULTS

Significant deviations in symmetry of antimere teeth were not detected (P >0.05). The volumes of mandibular central and lateral incisors in missing or peg-shaped lateral incisor groups were smaller than in the CG (P <0.05). Per quadrant analysis, volumes of the maxillary central incisor and mandibular central incisors, canines, and first molars in quadrants with missing or peg-shaped lateral incisors were smaller than in the control quadrants (P <0.05).

CONCLUSIONS

Neither unilateral nor bilateral presence of missing or peg-shaped maxillary lateral incisors affected the morphologic symmetry of antimere teeth but did affect tooth volume, especially in the mandibular arch.

Randomized controlled clinical study comparing two types of two‐piece dental implants supporting fixed restorations – results at 8 years of loading

Objectives

To assess clinical, technical, biological, and radiographic outcomes of implants supporting fixed restorations using two types of dental implants with non‐matching implant–abutment junctions at 8 years.

Materials and methods

Sixty‐four patients were randomly assigned to receive one of two implant systems (S1 or S2) and eventually fixed restorations. Patients were examined at loading (T_L), one (T₁), three (T₃), five (T₅), and eight years (T₈). Outcome measures included implant and restoration survival, technical and biological complications, and radiographic bone levels. All data were analyzed on the implant and patient level.

Results

Ninety‐eight implants were inserted in 64 patients and loaded with fixed restorations. At 8 years, 49 patients with 42 (S1) and 36 (S2) implants (25 in group S1 and 24 in group S2 on the patient level) were re‐examined. The survival rates on the patient level were 97.6% (S1) and 97.2% (S2). The marginal bone levels (the primary endpoint) amounted to a gain of 0.21 mm (Q1: −0.11 mm; Q3: 0.5 mm) (S1) (p = .007) and to a loss of 0.24 mm (Q1: −0.79 mm; Q3: 0.05 mm) (S2) (p = .001) between baseline (T_L) and T₈ (intergroup p < .001). The technical complication rates were 28% (S1) and 12.5% (S2) (intergroup p = .289). Peri‐implant mucositis was observed in 24% (S1) and 50% (S2) of the implants on the patient level (intergroup p = .792). The respective figures for peri‐implantitis were 0% (S1) and 12.5% (S2) (intergroup p = .11).

Conclusions

Dental implants with non‐matching implant–abutment junctions supporting fixed restorations resulted in high survival rates independent of the system used. Differences, mainly observed in terms of technical complications (in favor of S2), biological complications (in favor of S1), and marginal bone‐level changes (in favor of group S1), appear to be clinically negligible.

One-year outcomes of dental implants with a hybrid surface macro-design placed in patients with history of periodontitis: A randomized clinical trial

AIM

To evaluate the radiological, clinical, and microbiological outcomes of implants with a hybrid surface macro-design in patients with a history of periodontitis.

MATERIAL AND METHODS

The study was designed as a 12-month, parallel-arm, randomized controlled trial where patients with a history of treated periodontitis in need of dental implants for single-unit or short-span prosthesis were randomly allocated to a test [implants with a machined titanium surface in the coronal collar (hybrid; HS)] or a control group [conventional implants with moderately rough surface up to the implant shoulder (RS)]. Patients were followed at 3, 6, and 12 months after loading with assessment of radiological, clinical, and microbiological outcomes, as well as patient-related outcome measures (PROMs).

RESULTS

Forty patients were randomly assigned to either the RS group (n = 20) or the HS (n = 20) group. At 1 year, the mean marginal bone level changes were 0.22 [standard deviation (SD) 0.36] mm for the HS group and 0.22 (SD 0.29) mm for the RS group, with no significant differences between them (p = .961). Similarly, no significant differences in clinical, microbiological, or PROMs were observed between groups.

CONCLUSIONS

HS implants demonstrated radiographic, clinical, and microbiological characteristics equal to RS implants in patients with a history of periodontitis.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov (identifier NCT05010382).

Microgap and microleakage of a hybrid connection platform-switched implant system in the absence or presence of a silicone-based sealing agent

The present study aims to characterize, for the first time, the microgap and bacterial microleakage of a platform-switched implant system with hybrid connection, screwed at distinct torque values (manufacturer recommended torque-25 N cm-and a reduced torque-5 N cm-mimicking the long-term functional use), in the absence or presence of a silicon-based sealing agent. Microgap was determined through scanning electron microscopy and bacterial microleakage was evaluated in vitro, upon Enterococcus faecalis colonization of the system. The sealing efficacy was evaluated in the absence or presence of a commercially available silicon-based sealer. The cytotoxicity of the sealer was further addressed in vitro, with a fibroblastic cell line, in accordance with reference standards. A low microgap of the implant system was verified, regardless of the applied torque load-maximal values ranged around 0.25 and 1.25 µm, for 25 and 5 N cm torques, respectively. No bacterial microleakage was reported at 25 N cm, while at 5 N cm, leakage was verified on 38% of the samples. The application of a silicon-based sealer-with an adequate cytocompatible profile-was effective on preventing the bacterial microleakage on the assayed experimental setting. The assayed platform-switched implant system with hybrid connection presented a low interfacial misfit and an effective sealing capability at manufacturer recommended torque. Despite the increased microleakage at low torque conditions, the application of a cytocompatible silicon-based sealing agent restored the sealing effectiveness of the system. The use of a silicon-based sealing agent can assist on the maintenance of the sealing effectiveness even at low torque conditions.

Evaluation of the clinical performance of dentures manufactured by computer-aided technology and conventional techniques: A systematic review

STATEMENT OF PROBLEM

The introduction of computer-aided design and computer-aided manufacturing (CAD-CAM) technology for complete denture fabrication may have improved clinical outcomes compared with conventional techniques. However, systematic reviews comparing these techniques are lacking.

PURPOSE

The purpose of this systematic review was to identify, compare, and synthesize the outcomes of published clinical studies related to complete denture fabrication, with respect to the differences between CAD-CAM technology and conventional techniques.

MATERIAL AND METHODS

A comprehensive search of studies published up to March 16, 2020, was conducted by using the PubMed/MEDLINE, Web of Science, Cochrane Library, SciELO, and Embase databases according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement criteria and was registered in the International Prospective Register of Systematic Reviews (PROSPERO ID 42020202614). The population, intervention, comparison, and outcome (PICO) question was: Do CAD-CAM complete dentures have a similar functional performance to those fabricated by conventional techniques? The quality of publications was appraised by using the Critical Appraisal Skills Program (CASP) checklists.

RESULTS

Of the 1232 titles, 6 articles were selected. The studies reported better retention of digitally manufactured complete dentures without denture adhesives than that of conventional complete dentures with or without denture adhesives. Other studies reported that dentures manufactured with digital systems were better adapted to tissue surfaces, required less clinical time, were lower in cost, and provided better experience and satisfaction to patients.

CONCLUSIONS

The assessment of CAD-CAM planning and manufacturing through clinical studies is ongoing. However, preliminary results indicate better clinical performance and lower overall costs of digital complete dentures than conventional dentures.

Biomechanical evaluation of stress distributions at the implant-abutment complex and peri-implant bone around mandibular dental implants with different neck geometries and inclinations

This study aimed to investigate the effects of the different dental implant neck designs, diameters, and inclinations, on the stress distributions at the mandibular crestal bone and implant-abutment complex, using three-dimensional (3D) finite element stress analysis (FEA) method. Finite element models of three-unit fixed partial dentures supported with two same length implants (10 mm), placed on the second premolar and second molar regions, were designed. Eight different models were designed according to the implants' neck designs (platform switching/traditional), diameters (4.1 mm/4.8 mm) and the tilting angles of the posterior implants (0°/15°). The anterior implants' widths were 4.1 mm and the neck design of the anterior implants matched the posterior implants. Two types of 100-N loads in vertical and 30° oblique directions were applied separately onto each central fossae and functional cusps of the fixed partial dentures crowns. Algor Fempro Software was used for the simulation and evaluation of the stress levels at the implant-abutment complex and the crestal bone. Stress levels measured at the crestal bone were found to be lower for the platform switching models. However, the platform switching design generated higher stress magnitudes within the implant-abutment complex. Inclined placement of posterior implants increased the amount of stress at the crestal bone around both implants. Biomechanically, selection of the largest diameter possible when using tilted platform switched implants may be recommended at the posterior mandible.

The toxic effects of chloroquine and hydroxychloroquine on skeletal muscle: a systematic review and meta-analysis

The aim of this systematic review was to perform qualitative and quantitative analysis on the toxic effects of chloroquine (CQ) and hydroxychloroquine (HCQ) on skeletal muscles. We designed the study according to PRISMA guidelines. Studies for qualitative and quantitative analyses were selected according to the following inclusion criteria: English language; size of sample (> 5 patients), adult (> age of 18) patients, treated with CQ/HCQ for inflammatory diseases, and presenting and not presenting with toxic effects on skeletal muscles. We collected data published from 1990 to April 2020 using PubMed, Cochrane Library, EMBASE, and SciELO. Risk of bias for observational studies was assessed regarding the ROBIN-I scale. Studies with less than five patients (case reports) were selected for an additional qualitative analysis. We used the software Comprehensive Meta-Analysis at the confidence level of 0.05. We identified 23 studies for qualitative analysis (17 case-reports), and five studies were eligible for quantitative analysis. From case reports, 21 patients presented muscle weakness and confirmatory biopsy for CQ/HCQ induced myopathy. From observational studies, 37 patients out of 1,367 patients from five studies presented muscle weakness related to the use of CQ/HCQ, and 252 patients presented elevated levels of muscle enzymes (aldolase, creatine phosphokinase, and lactate dehydrogenase). Four studies presented data on 34 patients with confirmatory biopsy for drug-induced myopathy. No study presented randomized samples. The chronic use of CQ/HCQ may be a risk for drug-induced myopathy. There is substantiated need for proper randomized trials and controlled prospective studies needed to assess the clinical and subclinical stages of CQ/HCQ -induced muscle myopathy.

Computer-aided technology for fabricating removable partial denture frameworks: A systematic review and meta-analysis

STATEMENT OF PROBLEM

A consensus that establishes the indications and clinical performance of removable partial denture (RPD) frameworks designed and manufactured with computer-aided design and computer-aided manufacturing (CAD-CAM) systems is lacking.

PURPOSE

The purpose of this systematic review and meta-analysis was to evaluate the currently published literature investigating different CAD-CAM methods and techniques for RPD manufacturing and their clinical performance.

MATERIAL AND METHODS

A comprehensive search of studies published up to September 2019 was performed in PubMed/MEDLINE, Web of Science, Cochrane Library, and SciELO databases according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA Statement) criteria and was registered and approved in the International Prospective Register of Systematic Reviews (PROSPERO: CRD42020152197). The population, intervention, comparison, outcome (PICO) question was "Do the CAD-CAM frameworks have similar performances to those fabricated by conventional techniques?" The meta-analysis included clinical and in vitro studies based on the effect size and test of Null (2-Tail) with 95% confidence interval (CI). Clinical and in vitro studies were selected and analyzed separately.

RESULTS

A total of 15 articles out of 358 were selected. For clinical studies, quantitative analysis with a sample of 25 participants showed a mean discrepancy between occlusal rests and rest seats of 184.91 μm (95% CI: 152.6 μm-217.15 μm) and heterogeneity (I²) of 0%. Clinical data considered that frameworks were acceptable for continuity of treatment. The predominant materials were cobalt-chromium (Co-Cr) and polyetheretherketone (PEEK), and studies using Co-Cr reported that the structure required adjustments. In addition, it has been reported that the indirect technique was time-consuming and selective laser melting (SLM) can be costly. PEEK structures have been more widely accepted because of improved esthetics. Quantitative data from the in vitro studies revealed that the additive manufacturing technique (2.006 mm: 95% CI: -2.021 mm to 6.032 mm) was not significantly different from the indirect technique (0.026 mm; P=.455; random: I²: 98.402%).

CONCLUSIONS

Clinical studies and in vitro research on CAD-CAM planning and manufacturing of removable prosthesis frameworks are still sparse. However, preliminary data indicate a similar fit and esthetic improvement when compared with the conventional technique.

A Radiographic and Clinical Comparison of Immediate vs. Early Loading (4 Weeks) of Implants with a New Thermo-Chemically Treated Surface: A Randomized Clinical Trial

Background: Implant dentistry has evolved over time, resulting in better treatment outcomes for both patients and clinicians. The aim of this trial was to test whether the immediate loading of implants with a platform-switching design influences the marginal bone level, compared to four-week loading, after one year of follow-up. Moreover, a comparison of clinical data regarding implant survival, implant stability, and patient-reported outcome measures (PROMs) was conducted. Methods: Klockner^® VEGA^® implants with a ContacTi^® surface were placed in partially edentulous patients in the posterior areas. Group A received an immediately loaded prosthesis (one week) and Group B received an early-loaded prosthesis (four weeks). All abutments were placed at the time of surgery. Radiographic and clinical data were recorded. Results: Twenty-one patients were treated (35 implants). No implants were lost during the study. The final marginal bone level did not show differences between groups. The bone loss at 12 months at the implant level was 0.00 mm for both groups (median). The final implant quotient stability (ISQ) values did not differ between groups (median 73 and 70.25), nor did the other clinical parameters or PROMs. Conclusions: The results suggest that neither of the loading protocols with the implants used influenced the marginal bone level—not the osseointegration rate, clinical conditions, or PROMs.

Factors Affecting Implant Failure and Marginal Bone Loss of Implants Placed by Post-Graduate Students: A 1-Year Prospective Cohort Study

Statement of the problem: Most of the clinical documentation of implant success and survival published in the literature have been issued by either experienced teams from university settings involving strict patient selection criteria or from seasoned private practitioners. By contrast, studies focusing on implants placed and rehabilitated by inexperienced post-graduate students are scarce. Purpose: To record failure rates and identify the contributing factors to implant failure and marginal bone loss (MBL) of implants placed and rehabilitated by inexperienced post-graduate students at the one-year follow-up. Material and Methods: A prospective cohort study was conducted on study participants scheduled for implant therapy at the International University of Catalonia. An experienced mentor determined the treatment plan in accordance with the need of each participant who signed an informed consent. All surgeries and prosthetic rehabilitation were performed by the post-graduate students. Implant failure rate, contributors to implant failure, and MBL were investigated among 24 variables related to patient health, local site, and implant and prosthetic characteristics. The risk of implant failure was analyzed with a simple binary logistic regression model with generalized equation equations (GEE) models, obtaining unadjusted odds ratios (OR). The relationship between MBL and the other independent variables was studied by simple linear regression estimated with GEE models and the Wald chi² test. Results: One hundred and thirty dental implants have been placed and rehabilitated by post-graduate students. Five implants failed before loading and none after restoration delivery; survival and success rates were 96.15% and 94.62%, respectively. None of the investigated variables significantly affected the implant survival rate. At the one-year follow-up, the mean (SD) MBL was 0.53 (0.39) mm. The following independent variables significantly affected the MBL: Diabetes, implant depth placement. The width of keratinized tissue (KT) and probing depth (PD) above 3 mm were found to be good indicators of MBL, with each additional mm of probing depth resulting in 0.11 mm more MBL. Conclusion: The survival and success rates of dental implants placed and rehabilitated by inexperienced post-graduate students at the one-year follow-up were high. No contributing factor was identified regarding implant failure. However, several factors significantly affected MBL: Diabetes, implant depth placement, PD, and width of KT. Clinical Implications: Survival and success rates of dental implants placed and rehabilitated by inexperienced post-graduate students were high at the one-year follow-up, similar to experienced practitioners. No contributing factors were identified regarding implant failure; however, several factors significantly affected MBL: Diabetes, implant depth placement, PD, and KM.

Randomized clinical trial evaluating the effect of splinting crowns on short implants in the mandible 3 years after loading

OBJECTIVE

To compare the radiographic marginal bone loss and clinical parameters of splinted and non-splinted fixed dental prostheses on short implants in the posterior region of the lower jaw 3 years after loading.

MATERIAL AND METHODS

Twenty patients, 15 female and five males, with uni- or bilateral free-end situations in the mandible participated in the study. Two short implants (7 mm) in the posterior mandible were placed and patients were randomized to receive splinted (n = 11) or non-splinted (n = 13) cemented crowns. Marginal bone loss (MBL) was assessed on radiographs taken with customized positioning jigs at baseline, 1 and 3 years after loading. Plaque index (PI), gingival index (GI), probing depth (PD), and bleeding on probing (BOP) were measured. (ClinicalTrials.gov; identifier: NCT03558347).

RESULTS

After 3-year survival rate of altogether 48 implants was 100% for both groups. Success rate (according to Papaspyridakos, Chen, Singh, Weber, & Gallucci, 2012) was 84.6% for non-splinted and 86.4% for splinted implants. At restoration level survival rate was 100% for both groups. Marginal bone level changes showed mean gain of 0.3 ± 0.8 mm for non-splinted and 0.1 ± 0.5 mm for splinted implants 3 years after loading. Statistical analysis showed no significant difference in PI, GI, PD, BOP, and marginal bone loss between both groups (p > .05).

CONCLUSION

Within the limitations of this study it can be concluded that splinting crowns on short implants neither seems to affect the amount of marginal bone loss nor peri-implant health 3 years after loading.

Is There a Role for Absorbable Metals in Surgery? A Systematic Review and Meta-Analysis of Mg/Mg Alloy Based Implants

Magnesium (Mg) alloys have received attention in the literature as potential biomaterials for use as absorbable implants in oral and maxillofacial and orthopedic surgery applications. This study aimed to evaluate the available clinical studies related to patients who underwent bone fixation (patients), and received conventional fixation (intervention), in comparison to absorbable metals (comparison), in terms of follow-up and complications (outcomes). A systematic review and meta-analysis were performed in accordance with the PRISMA statement and PROSPERO (CRD42020188654), PICO question, ROBINS-I, and ROB scales. The relative risk (RR) of complications and failures were calculated considering a confidence interval (CI) of 95%. Eight studies (three randomized clinical trial (RCT), one retrospective studies, two case-control studies, and two prospective studies) involving 468 patients, including 230 Mg screws and 213 Titanium (Ti) screws, were analyzed. The meta-analysis did not show any significant differences when comparing the use of Mg and Ti screws for complications (p = 0.868). The estimated complication rate was 13.3% (95% CI: 8.3% to 20.6%) for the comparison group who received an absorbable Mg screw. The use of absorbable metals is feasible for clinical applications in bone surgery with equivalent outcomes to standard metal fixation devices.

The influence of acetylsalicylic acid on bone regeneration: systematic review and meta-analysis

Acetylsalicylic acid (ASA) is commonly used as a non-steroidal anti-inflammatory drug that interferes with multiple biological pathways. ASA acts by stimulating osteogenesis and inhibiting osteoclastogenesis. Thus, the objective of this study was to perform a systematic review and meta-analysis to evaluate the effectiveness of the use of ASA in the bone regeneration in animal models. This review was structured based on the PRISMA Statement and registered on PROSPERO database according to protocol number #CDR42018111403. The quality of evidence was assessed by using the Grades of Recommendation, Assessment, Development, and Evaluation (GRADE). With the development of search strategies, we identified studies on the use of ASA from the following databases: 1- Medline (via PubMed); 2 - Web of Science; 3 - Scopus; and 4 - EMBASE. A total of 296 articles were identified and after screening the title, abstract, and full text, only 18 studies were selected for qualitative analysis and 12 were selected for performance of the quantitative analysis (meta-analysis). A meta-analysis of the amount of bone tissue formed showed a significant advantage when ASA was locally used, revealing a mean difference (MD) of 22.75% (95% CI: 15.39-30.12) p < 0.00001. Within the limitations of the available data, the results were promising and showed that ASA can be effective in bone formation in animal models.

Quality Assessment of Systematic Reviews on Platform-Switching vs Platform-Matched Implants: An Overview

The objective of this study was to perform a quality analysis of systematic reviews with meta-analyses that focused on the comparison of platform-switching (implant-abutment mismatching) and platform-matched (PM) implants. The assessment of multiple systematic reviews (AMSTAR) and Glenny (Checklist) Scales were used to qualify the studies. PubMed, Scientific Electronic Library Online (SciELO), Web of Science (formerly ISI Web of Knowledge), and Cochrane databases were searched, by topic, for systematic reviews on dental implants with switching platforms. A total of 8 systematic reviews, including 7 studies with meta-analyses, were selected. The AMSTAR scale indicated a high (n = 6) to moderate (n = 2) score for the included studies. The quantitative analysis indicated that platform-switching implants preserved more bone tissue when compared with platform-matched implants (6 meta-analyses; P < .001, smaller mean difference: -0.29 mm, 95% CI: -0.38, -0.19 and greater mean difference: -0.49 mm, 95% CI: -0.73, -0.26). Quantitative analysis based on 7 systematic reviews with meta-analysis indicated positive peri-implant bone preservation for implants restored with an implant-abutment mismatching (PSW). Further, there is evidence to improve the design of current systematic reviews. Future systematic reviews in this thematic area should consider searches in gray literature and different databases and include only randomized controlled clinical studies.

Dental Implants with Different Neck Design: A Prospective Clinical Comparative Study with 2-Year Follow-Up

The present study was conducted to investigate whether a different implant neck design could affect survival rate and peri-implant tissue health in a cohort of disease-free partially edentulous patients in the molar–premolar region. The investigation was conducted on 122 dental implants inserted in 97 patients divided into two groups: Group A (rough wide-neck implants) vs. Group B (rough reduced-neck implants). All patients were monitored through clinical and radiological checkups. Survival rate, probing depth, and marginal bone loss were assessed at 12- and 24-month follow-ups. Patients assigned to Group A received 59 implants, while patients assigned to Group B 63. Dental implants were placed by following a delayed loading protocol, and cemented metal–ceramic crowns were delivered to the patients. The survival rates for both Group A and B were acceptable and similar at the two-year follow-up (96.61% vs. 95.82%). Probing depth and marginal bone loss tended to increase over time (follow-up: t₁ = 12 vs. t₂ = 24 months) in both groups of patients. Probing depth (p = 0.015) and bone loss (p = 0.001) were significantly lower in Group A (3.01 vs. 3.23 mm and 0.92 vs. 1.06 mm; Group A vs. Group B). Within the limitations of the present study, patients with rough wide-neck implants showed less marginal bone loss and minor probing depth, as compared to rough reduced-neck implants placed in the molar–premolar region. These results might be further replicated through longer-term trials, as well as comparisons between more collar configurations (e.g., straight vs. reduced vs. wide collars).

Frequency of adequate mesiodistal space and faciolingual alveolar width for implant placement at anterior tooth positions

BACKGROUND

Prior studies have defined minimum mesiodistal space (MS) and faciolingual alveolar width (FAW) requirements for dental implant sites, and failure to observe these constraints may adversely impact peri-implant health and esthetics. However, to the authors' knowledge, no previous reports have established frequencies at which anterior tooth positions present favorable MS and FAW for implant accommodation.

METHODS

A single examiner analyzed 205 cone-beam computed tomographic images, recording MS and FAW available for implant placement at anterior tooth positions. The examiner compared measurements with standardized implant diameters to assess anticipated implant-to-tooth distances and peri-implant bone thicknesses.

RESULTS

In the esthetic zone, lateral incisor sites most frequently failed to present favorable MS. At maxillary lateral incisor positions, 22% (left) and 27% (right) of sites offered less than 2 millimeters between the proposed implant platform and the adjacent teeth. In mandibular incisor positions, implant-to-tooth distance was less than 2 mm at 79% through 97% of sites and less than 1.5 mm at 35% through 76% of sites. Over one-half of maxillary incisor sites and 78% through 95% of mandibular incisor sites exhibited FAW of less than 4 mm beyond implant diameter.

CONCLUSIONS

In the population evaluated, mandibular incisor positions frequently presented unfavorable MS to accommodate conventional narrow-diameter implants. In addition, considerable proportions of mandibular incisor and maxillary lateral incisor sites may be at risk of developing unfavorable peri-implant bone thickness when conventional narrow-diameter implants are used.

PRACTICAL IMPLICATIONS

Practitioners should consider small-diameter implants and nonimplant tooth replacement methods for many patients missing single mandibular incisors or maxillary lateral incisors.

Does the implant-abutment interface interfere on marginal bone loss? A systematic review and meta-analysis

The objective of this systematic review was to compare the conical internal connection (IC) with the external hexagonal connection (EH) on the occurrence of marginal bone loss (ΔMBL). Different databases were used to carry out the selection of the elected studies. The studies were judged according to the risk of bias as "high", "low" and "unclear" risk. For the meta-analysis we included only studies that could extract the data of ΔMBL, survival rate (SR) and probing depth (PD). No statistically significant differences were found for ΔMBL data at one, three- and five-year survival rates between implant connections (p <0.05), however statistically significant differences were found for PD between EH and IC implants (1-year follow-up) -0.53 [95%CI -0.82 to -0.24, p = 0.0004]. This present systematic review demonstrated that there are no significant differences between IC and EH implants for both ΔMBL and SR at 1, 3 e 5 years after functional loading, although better PD values were observed for implants pertaining to the IC connections. Considering the high heterogeneity, more well-delineated, randomized clinical trials should be conducted.

Factors Influencing Early Marginal Bone Loss around Dental Implants Positioned Subcrestally: A Multicenter Prospective Clinical Study

Early marginal bone loss (MBL) is a non-infective remodeling process of variable entity occurring within the first year after implant placement. It has a multifactorial etiology, being influenced by both surgical and prosthetic factors. Their impact remains a matter of debate, and controversial information is available, particularly regarding implants placed subcrestally. The present multicenter prospective clinical study aimed to correlate marginal bone loss around platform-switched implants with conical connection inserted subcrestally to general and local factors. Fifty-five patients were enrolled according to strict inclusion/exclusion criteria by four clinical centers. Single or multiple implants (AnyRidge, MegaGen, South Korea) were inserted in the posterior mandible with a one-stage protocol. Impressions were taken after two months of healing (T1), screwed metal-ceramic restorations were delivered three months after implant insertion (T2), and patients were recalled after six months (T3) and twelve months (T4) of prosthetic loading. Periapical radiographs were acquired at each time point. Bone levels were measured at each time point on both mesial and distal aspects of implants. Linear mixed models were fitted to the data to identify predictors associated with MBL. Fifty patients (25 male, 25 female; mean age 58.0 ± 12.8) with a total of 83 implants were included in the final analysis. The mean subcrestal position of the implant shoulder at baseline was 1.24 ± 0.57 mm, while at T4, it was 0.46 ± 0.59 mm under the bone level. Early marginal bone remodeling was significantly influenced by implant insertion depth and factors related to biological width establishment (vertical mucosal thickness, healing, and prosthetic abutment height). Deep implant insertion, thin peri-implant mucosa, and short abutments were associated with greater marginal bone loss up to six months after prosthetic loading. Peri-implant bone levels tended to stabilize after this time, and no further marginal bone resorption was recorded at twelve months after implant loading.

Clinical outcomes of pterygoid implants: Systematic review and meta-analysis

The aim of this systematic literature review was to analyze clinical outcomes of pterygoid implant for the treatment of patients with atrophic posterior maxillae and to provide clinical recommendations for this dental implant technique. An extensive search of electronic databases (PubMed/Medline, Science Direct, Lilacs, Embase, and Cochrane Library) was conducted, for articles published between January 1995 and January 2018, to identify literature presenting clinical outcomes of pterygoid implants in the treatment of patients with atrophic posterior maxillae. The systematic review was performed in accordance with PRISMA/PICO statement guidelines, and the risk of bias was assessed (Australian National Health and Medical Research Council scale). The relative risk of implant failure was analyzed within a 95% confidence interval (95% CI). After screening 331 abstracts from the electronic databases, 36 full-text articles were accessed for eligibility, and a total of 6 studies were included in this systematic review (after applying the inclusion and exclusion criteria). All studies were retrospective in nature and were classified with a poor level of evidence. A total of 634 patients received 1.893 pterygoid implants, with a mean implant survival rate of 94.87%. The mean prevalence of implant failure was 0.056 with a 95% CI of 0.04-0.077. This study demonstrates that pterygoid implants can be successfully used in patients with atrophic posterior maxilla. However, the results should be interpreted with caution, given the presence of uncontrolled confounding factors in the included studies.

Systematic review of hormonal and genetic factors involved in the nonsyndromic disorders of the lower jaw

Mandibular disorders are among the most common birth defects in humans, yet the etiological factors are largely unknown. Most of the neonates affected by mandibular abnormalities have a sequence of secondary anomalies, including airway obstruction and feeding problems, that reduce the quality of life. In the event of lacking corrective surgeries, patients with mandibular congenital disorders suffer from additional lifelong problems such as sleep apnea and temporomandibular disorders, among others. The goal of this systematic review is to gather evidence on hormonal and genetic factors that are involved in signaling pathways and interactions that are potentially associated with the nonsyndromic mandibular disorders. We found that members of FGF and BMP pathways, including FGF8/10, FGFR2/3, BMP2/4/7, BMPR1A, ACVR1, and ACVR2A/B, have a prominent number of gene-gene interactions among all identified genes in this review. Gene ontology of the 154 genes showed that the functional gene sets are involved in all aspects of cellular processes and organogenesis. Some of the genes identified by the genome-wide association studies of common mandibular disorders are involved in skeletal formation and growth retardation based on animal models, suggesting a potential direct role as genetic risk factors in the common complex jaw disorders. Developmental Dynamics 248:162-172, 2019. © 2018 Wiley Periodicals, Inc.

Reciprocating kinematics leads to lower incidences of postoperative pain than rotary kinematics after endodontic treatment: A systematic review and meta-analysis of randomized controlled trial

Background:

Extrusion of infected debris into the periapical tissue has been cited as the major cause of postoperative pain, regardless of instrumentation technique.

Aim:

Comprehensively review two different kinematics of instrumentation (reciprocating and rotary) and association to the postoperative pain after endodontic treatment.

Methods:

Two investigators performed a systematic review with meta-analysis. MEDLINE/PubMed, Cochrane Library, and Scopus supplied relevant data from studies published until February 2018 to answer the PICO question. Primary outcome was overall postoperative pain, and the secondary outcomes were nature of the pain (mild, moderate, and severe) at 12, 24, and 48 h.

Results:

Ten randomized clinical trials fulfilled eligibility criteria, and five of them were submitted in the meta-analysis. Primary outcome indicated that reciprocating system results in less postoperative pain compared to rotary system (P < 0.05). As a secondary outcome, there was no statistical difference for mild, moderate, and severe pain after 12 and 24 h using reciprocating or rotary systems (P > 0.05). However, the reciprocation system showed less severe pain after 48 h (P < 0.05).

Conclusion:

Rotary motion had a negative impact on postoperative pain after endodontic treatment. Furthermore, after 48 h, more patients presented severe pain under rotary motion. More randomized clinical studies would be helpful.

Optimal number of implants for complete-arch implant-supported prostheses with a follow-up of at least 5 years: A systematic review and meta-analysis

STATEMENT OF PROBLEM

Consensus is lacking regarding the optimal number of implants for supporting complete-arch prostheses with good survival rates and lower prosthetic complications and marginal bone loss.

PURPOSE

The purpose of this systematic review was to evaluate the influence of the number of implants used for complete-arch prostheses with at least 5 years of follow-up.

MATERIAL AND METHODS

A search was performed in the PubMed/MEDLINE, Scopus, and Cochrane Library databases according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria and was registered in The International Prospective Register of Systematic Reviews (CRD42016048468). The following was the population, intervention, comparison, outcome (PICO) question: Does the number of implants influence the longevity of complete-arch prostheses?

RESULTS

Nineteen studies including 1006 patients with a mean age of 61.44 years were selected for evaluation. The number of implants per jaw ranged between 2 and 9 in the maxilla, mandible, or both jaws. For implant survival rate in complete-arch prostheses with fewer than 5 implants per jaw, the pooled weighted event rate was 1.4% (I²=25.26%; P=.211) and 4.2% (I²=81.35%; P<.001) for complete arches with more than 4 implants per jaw. For the prosthesis survival rate, the pooled weighted event rate for a complete-arch with fewer than 5 implants per jaw was 1.5% (I²=0%; P=.677) and 9% (I²=17.33%; P=.304) for complete arches with more than 4 implants per jaw. For prosthesis complications for complete arches with fewer than 5 implants per jaw, the pooled weighted event rate was 19.9% (I²=93.5%; P<.001) and 24.5% (I²=88.89; P<.001) for complete arches with more than 4 implants per jaw. The mean marginal bone loss for complete arches with fewer than 5 implants per jaw was 1.22 ±0.49 mm (I²=99.46; P<.001) and 1.46 ±0.46 mm (I²=99.6; P <.001) for more than 4 implants per jaw.

CONCLUSIONS

The current systematic review indicated no relationship of the number of implants used to support a complete-arch prosthesis with implant survival rate, prosthesis survival rate, prosthesis complications, or marginal bone loss in studies with follow-up periods of between 5 and 15 years.

Can Genetic Factors Compromise the Success of Dental Implants? A Systematic Review and Meta-Analysis

Dental implants provide a predictable treatment option for partial and complete edentulism via the placement of a fixed permanent artificial root to support prosthetic dental crowns. Despite the high survival rates, long-term dental implant failures are still reported, leading to implant removals and additional financial and health burdens. While extrinsic factors that improve the success rate of implants have been well explored, the impact of genetic factors on this matter is poorly understood. A systematic review and meta-analysis study was conducted to determine whether genetic factors contribute to an increased risk of dental implant failures. A comprehensive search for peer-reviewed articles on dental implants and genetic factors was performed using various literature database libraries. The study design was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines, and the obtained records were registered in the International Prospective Register of Systematic Reviews (PROSPERO) database. According to the exclusion/inclusion criteria, 13 studies were eligible for this study out of 809 articles. The meta-analysis of the combined association studies of DNA variations and dental implants did not indicate an increased risk for implant failure due to DNA variations in IL-1B, IL-10 and TNF-α. This study emphasizes the need for larger randomized controlled clinical trials to inform clinicians and patients about the role of genetic factors on dental implant survival and the success rate in healthy and compromised patients.

Peri-implant tissue healing at implants with different designs and placement protocols: An experimental study in dogs

OBJECTIVES

To compare the peri-implant tissue response to subcrestal or crestal placement of implants with or without "platform-switched" implant/abutment connections.

MATERIAL AND METHODS

On each side of the mandible in six Labrador dogs, two "platform-switched" (PS) implants and two implants with matching implant/abutment diameters (PM) were placed in a crestal or a 1.5 mm subcrestal position. Sulcus formers/abutments were connected, baseline radiographs obtained and the distance between the abutment-fixture junction (A/F) and the marginal bone level (B) was determined. Five months later, radiographic and clinical examinations were repeated and biopsies were obtained and processed for histological analysis.

RESULTS

The radiographic analysis showed that marginal bone level changes occurred during the first observation period (13 weeks). PS-implants showed minor marginal bone level alterations during the full observation period (20 weeks), regardless of placement depth. For PM-implants, placement had a significant impact on bone level changes; crestal placement resulted in a mean bone loss of 0.4 mm and subcrestal placement in a 1.5 mm bone loss. The histometric measurements resulted in a distance A/F-B of 0.6 and 0.0 mm for PS implants, placed in a crestal or subcrestal position, respectively. The corresponding distance at PM-implants was 1.5 mm irrespective of placement protocol. The peri-implant mucosa was thicker at subcrestally placed implants as compared to a crestal placement.

CONCLUSIONS

Bone remodeling occurred within the early healing phase. During the full 20 weeks of observation, PS-implants demonstrated significantly less crestal bone loss compared to PM-implants.

Dental Implants

Systematic reviews of literature over the period between 2008 and 2017 are discussed regarding clinical evidence for the factors affecting survival and failure of dental implants. The factors addressed include publication bias, tooth location, insertion torque, collar design, implant-abutment connection design, implant length, implant width, bone augmentation, platform switching, surface roughness, implant coatings, and the use of ceramic materials in the implant body and abutment.

Should the restoration of adjacent implants be splinted or nonsplinted? A systematic review and meta-analysis

STATEMENT OF PROBLEM

The decision to splint or to restore independently generally occurs during the planning stage, when the advantages and disadvantages of each clinical situation are considered based on the proposed treatment. However, clinical evidence to help clinicians make this decision is lacking.

PURPOSE

The purpose of this systematic review and meta-analysis was to assess the marginal bone loss, implant survival rate, and prosthetic complications of splinted and nonsplinted implant restorations.

MATERIAL AND METHODS

This study was designed according to the Cochrane criteria for elaborating a systematic review and meta-analysis and adopted the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement. Also, this review was registered at the International Prospective Register of Systematic Reviews (PROSPERO) (CRD42017080162). An electronic search in the PubMed/MEDLINE, Cochrane Library, and Scopus databases was conducted up to November 2017. A specific clinical question was structured according to the population, intervention, comparison, outcome (PICO) approach. The addressed focused question was "Should the restoration of adjacent implants be splinted or nonsplinted?" The meta-analysis was based on the Mantel-Haenszel and inverse variance methods to assess the marginal bone loss, implant survival, and prosthetic complications of splinted and nonsplinted implant restorations.

RESULTS

Nineteen studies were selected for qualitative and quantitative analyses. A total of 4215 implants were placed in 2185 patients (splinted, 2768; nonsplinted, 1447); the mean follow-up was 87.8 months (range=12-264 months). Quantitative analysis found no significant differences between splinted and nonsplinted restorations for marginal bone loss. The assessed studies reported that 75 implants failed (3.4%), of which 24 were splinted (99.1% of survival rate) and 51 were nonsplinted (96.5% of survival rate). Quantitative analysis of all studies showed statistically significant higher survival rates for splinted restorations than for nonsplinted restorations. Ceramic chipping, screw loosening, abutment screw breakage, and soft tissue inflammation were reported in the selected studies. The quantitative analysis found no statistically significant difference in the prosthetic complications of splinted and nonsplinted restorations.

CONCLUSIONS

Within the limitations of this systematic review and meta-analysis, it was concluded that there was no difference in the marginal bone loss and prosthetic complications of splinted and nonsplinted implant restorations; this is especially true for restorations in the posterior region. However, splinted restorations were associated with decreased implant failure.

Biomechanical analysis of different implant-abutments interfaces in different bone types: An in silico analysis

The purpose of this study was to analyze the stress distribution of bone tissue around implants with different implant-abutment interfaces: platform switching (PSW); external hexagon (EH) and Morse taper (MT) with different diameters (regular: Ø 4 mm and wide: Ø 5 mm), bone types (I-IV) and subjected to axial and oblique load conditions using three-dimensional finite element analysis (3D-FEA). Sixteen 3D models of various configurations were simulated using InVesalius, Rhinoceros 3D 4.0, and SolidWorks 2011 software, and processed using Femap 11.2 and NeiNastran 11.0 programs. Axial and oblique forces of 200 N and 100 N, respectively, applied at the occlusal surface of prostheses. Maximum principal stress values were obtained from the peri-implant cortical bone of each model. Statistical analyses were performed using ANOVA and Tukey's test for maximum principal stress values. Oblique loading showed higher tensile stress than axial loading (P < 0.001). Wide-diameter implants showed lower stress concentration rather than regular-diameter implants, regardless of both connection and bone type (P < 0.001). Under axial loading, wide-diameter EH implants with regular platforms showed more favorable stress distribution than PSW implants for axial loading (P < 0.001); however, under oblique loading, PSW implants exhibited lower stress concentrations (P < 0.001). Regular-diameter MT implants showed lower stress than EH implants (P < 0.001). Bone type IV showed higher stress in the cortical region than bone types I and II (P < 0.001), but no significant difference when compared with bone type III (P > 0.05). The conclusion drawn from this in silico is that MT implants should be considered for use in situations that preclude the placement of wide-diameter implants, particularly where bone types III and IV are concerned.

One-time versus repeated abutment connection for platform-switched implant: A systematic review and meta-analysis

Objective

This review aims to compare peri-implant tissue changes in terms of clinical and radiographic aspects of implant restoration protocol using one-time abutment to repeated abutment connection in platform switched implant.

Method

A structured search strategy was applied to three electronic databases, namely, Pubmed, Embase and Web of Science. Eight eligible studies, including seven randomised controlled studies and one controlled clinical study, were identified in accordance with inclusion/exclusion criteria. Outcome measures included peri-implant bone changes (mm), peri-implant soft tissue changes (mm), probing depth (mm) and postsurgical complications.

Result

Six studies were pooled for meta-analysis on bone tissue, three for soft tissue, two for probing depth and four for postsurgical complications. A total of 197 implants were placed in one-time abutment group, whereas 214 implants were included in repeated abutment group. The implant systems included Global implants, Ankylos, JDEvolution (JdentalCare), Straumann Bone level and Conelog-Screwline. One-time abutment group showed significantly better outcomes than repeated abutment group, as measured in the standardised differences in mean values (fixed- and random-effect model): vertical bone change (0.41, 3.23) in 6 months, (1.51, 14.81) in 12 months and (2.47, 2.47) in 3 years and soft tissue change (0.21, 0.23). No significant difference was observed in terms of probing depth and complications.

Conclusion

Our meta-analysis revealed that implant restoration protocol using one-time abutment is superior to repeated abutment for platform switched implant because of less bone resorption and soft tissue shifts in former. However, future randomised clinical trials should be conducted to further confirm these findings because of the small samples and the limited quality of the original research.

Dental implants in patients with osteoporosis: a systematic review with meta-analysis

There is currently no consensus regarding the survival rate of osseointegrated implants in patients with osteoporosis. A systematic review with meta-analysis was performed to evaluate the survival rate of implants in such patients. The PubMed/MEDLINE, Web of Science, Cochrane Library, and SciELO databases were used to identify articles published up to September 2016. The systematic review was performed in accordance with PRISMA/PICO requirements and the risk of bias was assessed (Australian National Health and Medical Research Council scale). The relative risk (RR) of implant failure and mean marginal bone loss were analyzed within a 95% confidence interval (CI). Fifteen studies involving 8859 patients and 29,798 implants were included. The main outcome of the meta-analysis indicated that there was no difference in implant survival rate between patients with and without osteoporosis, either at the implant level (RR 1.39, 95% CI 0.93-2.08; P=0.11) or at the patient level (RR 0.98, 95% CI 0.50-1.89; P=0.94). However, the meta-analysis for the secondary outcome revealed a significant difference in marginal bone loss around implants between patients with and without osteoporosis (0.18mm, 95% CI 0.05-0.30, P=0.005). Data heterogeneity was low. An increase in peri-implant bone loss was observed in the osteoporosis group. Randomized and controlled clinical studies should be conducted to analyze possible biases.

Comparison between piezoelectric surgery and conventional saw in sagittal split osteotomies: a systematic review

A systematic review of the advantages and disadvantages of piezoelectric surgery in comparison with conventional saws for sagittal split osteotomy (SSO) was performed. Relevant studies published in the last 10 years were identified through a search of the PubMed/MEDLINE, Science Direct, and Embase databases and assessed against predetermined eligibility criteria. The initial search resulted in 1736 articles. After applying the inclusion and exclusion criteria, 12 articles remained. A total of 799 patients with an average age of 27.5 years underwent SSO performed using a saw or ultrasonic device. Results showed that it took longer to perform the osteotomies using an ultrasonic device than using a conventional saw. At ≥6 months of follow-up, neurosensory disturbance was seen in 4.7% of patients who underwent piezoelectric surgery versus 61.6% of patients who underwent surgery in which a conventional saw was used. It was found that the use of piezoelectric surgery in SSO leads to the best outcome regarding neurosensory disturbance when compared to conventional saws (P=0.04) at ≥6 months of follow-up. Further studies are required for the evaluation of the other clinical parameters assessed.