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

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.

Associations among gene polymorphisms, crestal bone loss, and bone mineral density in patients receiving dental implants

Objectives

Interleukin 1 (IL-1) and interleukin 6 (IL-6) gene polymorphisms have been suggested to be responsible for diminished bone mineral density (BMD) and high crestal bone loss (CBL) in some individuals. However, the effects of systemic BMD on variations in peri-implant CBL are unclear. Hence, this study was aimed at investigating the association of IL-1 and IL-6 gene polymorphisms with systemic BMD and CBL around dental implants.

Methods

A total of 190 participants undergoing dental implantation in the mandibular posterior region were selected according to predetermined selection criteria and divided into a normal BMD group (NBD, 93 participants, T-score ≥ -1) and low BMD group (LBD, including both osteoporosis and osteopenia, 97 participants, T-score < -1 standard deviation) according to the BMD of the right femoral neck, measured with dual-energy X-ray absorptiometry. Dental implants were placed through the standard surgical protocol, and CBL was calculated after 6 months with cone beam computed tomography scans before second-stage surgery. Genotyping was performed on all participants for IL-1A-889 A/G, IL-1B-511G/A, IL-1B+3954, and IL-6-572 C/G gene polymorphisms.

Results

The demographic and clinical characteristics of the participants in both groups were compared with t-test and chi-square test (χ2). The associations of NBD and LBD with the different genotypes and CBL was determined with odds ratios, and p < 0.05 was considered statistically significant. The frequency of IL-1B-511AA and IL-6-572 GG genotypes was significantly higher in LBD than in NBD (p < 0.05). In LBD, the IL-1B-511 AA (AA vs GA + GG; p ≤ 0.001) and IL-6-572 GG (GG vs CC + GC; p = 0.001) genotypes were significantly associated with higher peri-implant CBL.

Conclusions

Individuals with the IL-1B-511 AA or IL-6-572 GG genotype had elevated risk of osteoporosis/osteopenia and were more susceptible to CBL around dental implants.

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.

Association of interleukin-1, interleukin-6, collagen type I alpha 1, and osteocalcin gene polymorphisms with early crestal bone loss around submerged dental implants: A nested case control study

STATEMENT OF PROBLEM

The reason for variations in peri-implant early crestal bone loss is unclear but may be due to genetic differences among individuals.

PURPOSE

The purpose of this nested case control study was to investigate the association of single-nucleotide polymorphisms of interleukin-1, interleukin-6, collagen type I alpha1, and osteocalcin genes to early crestal bone loss around submerged dental implants.

MATERIAL AND METHODS

Dental implants were placed in the mandibular posterior region (single edentulous space) of 135 participants selected according to predetermined selection criteria. Bone mineral density measurement by using dual energy X-ray absorptiometry, cone beam computed tomography scans at the baseline and after 6 months, and interleukin-1A-889 A/G (rs1800587), interleukin-1B-511 G/A (rs16944), interleukin-1B+3954 (rs1143634), interleukin-6-572 C/G (rs1800796), collagen type I alpha1 A/C (rs1800012), and osteocalcin C/T (rs1800247) genotyping were performed in all participants. Early crestal bone loss measured around dental implants was used to group participants into clinically significant bone loss (BL)>0.5 mm and clinically nonsignificant bone loss (NBL)≤0.5 mm. Early crestal bone loss was calculated as the mean of the difference of bone levels at the baseline and bone levels after 6 months as measured with cone beam computed tomography scans. The obtained data for basic characteristics, early crestal bone loss, and genotyping were tabulated and compared by using a statistical software program (α=.05).

RESULTS

AA genotype and the A allele frequency of interleukin-1B-511 and GG genotype and the G allele frequency of interleukin-6-572 were significantly higher in BL than in NBL (P<.05). Multiple logistic analysis suggested that interleukin-1B-511 AA/GG+AG and interleukin-6-572 GG/CC+CG genotype expression were significantly associated with early crestal bone loss (AA/GG+AG; P=.014, GG/CC+CG; P=.047) around dental implants. Other risk factors were not significantly different (P>.05).

CONCLUSIONS

Of the genes studied, individuals with interleukin-1B-511 AA (rs16944) or interleukin-6-572 GG (rs1800796) genotype had higher susceptibility to early crestal bone loss around dental implants.

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.

Association between Interleukin-1 Polymorphisms and Susceptibility to Dental Peri-Implant Disease: A Meta-Analysis

Background and objective: Interleukins (ILs), as important biochemical mediators, control the host response to inflammation and are associated with bone resorption. In the present meta-analysis, we investigated the association between IL−1 polymorphisms and susceptibility to dental peri-implant disease (PID). Materials and methods: We searched Web of Science, Cochrane Library, Scopus, and PubMed/Medline databases for studies published until 9 September2021, without any restrictions. We calculated the crude OR and 95% confidence intervals (CI) to estimate the associations between IL−1 polymorphisms and PID risk in the five genetic models. We further performed the subgroup analysis, sensitivity analysis, meta-regression, trial sequential analysis, and calculated the publication bias. Results: Out of 212 retrieved records, sixteen articles were used in the meta-analysis. There was no association between IL−1A (–889), IL−1B (−511), IL−1B (+3953), and IL−1RN (VNTR) polymorphisms and the risk of dental PIDs, but there was an increased risk of IL−1B (+3954) in the patients with PIDs. In addition, an association of the composite genotype of IL−1A (−889)/IL−1B (+3953) was observed with the risk of PIDs, but not for the composite genotype of IL−1A (−889)/IL−1B (+3954). The publication year, the ethnicity, sample size, and the outcome were significantly influenced pooled estimates of some genetic models. Trial sequential analysis showed the lack of sufficient sample sizes in the studies. Conclusions: Among IL−1 polymorphisms evaluated in the meta-analysis, the composite genotype of IL−1A (−889)/IL−1B (+3953) and IL−1B (+3954) were the only polymorphisms associated with the risk of PID. The T allele and CT genotype of IL−1B (+3954) polymorphism were also associated with an elevated risk of PID.

Association of interleukin-1 gene polymorphism and early crestal bone loss around submerged dental implants: A systematic review and meta-analysis

Aim:

Early crestal bone loss (ECBL) has been observed regardless of the absence of possible etiologic factors for bone loss during the healing phase and before the second-stage implant surgery. The purpose of this systematic review and meta-analysis was to correlate the possible association of interleukin-1 (IL-1) gene polymorphisms and ECBL (bone loss before the second-stage surgery) around dental implants.

Settings and Design:

Systematic review and meta-analysis following PRISMA guidelines.

Materials and Methods:

Considering the inclusion criteria, an electronic search by using specific keywords of three databases PubMed [(“Dental” OR “oral”) AND (“Implants*”) AND (“gene polymorphism” OR “genotype” AND (“IL-1” OR “interleukins”)], Cochrane library [implant AND (biomarker or cytokine), interleukin-1 or IL-1 AND implants], and EMBASE [(“gene polymorphisms”/de OR “interleukins”/cytokine exp OR “biomarker”:ti,ab,kw) AND (“dental implantation”/de OR “oral implant”)] and manual search from 1995 till March 2020 was made by 2 independently calibrated reviewers. ACROBAT-NRSI, Version 1.0.0 and Review Manager, Version 5.3, computer software were used for the risk of bias assessment and to conduct the meta-analysis respectively.

Statistical Analysis Used:

Cochran's Q test and I² statistics.

Results:

Of 38 articles which were found eligible for full-text screening, two articles fulfilled the inclusion criteria and hence were included in the meta-analysis. The I² statistic and Q-test values of the included studies revealed acceptable homogeneity for studied three IL-1 gene polymorphisms (IL-1A−889: I² =0%, IL-1B − 511: I² = 0%, IL-1B+3954: I² = 24%). Forest plot of association between IL-1B−511 gene and ECBL revealed a significant association between 2/2 genotype of IL-1B−511 gene and an increased risk of ECBL (OR = 0.23, 95% CI = 0.09–0.58, P_{heterogeneity}= 0.68, I² = 0%, and P = 0.002). Results of the IL-1A−889 and IL-1B+3954 gene revealed no significant associations between any genotype of these genes with risk of ECBL.

Conclusions:

There is an evidence of the association of IL-1B−511 (2/2) genetic polymorphisms and increased ECBL in the individuals of Asian ethnicity (OR = 0.23, P = 0.002).

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.

Association of IL-10 and TNF-α Polymorphisms with Dental Peri-Implant Disease Risk: A Meta-Analysis, Meta-Regression, and Trial Sequential Analysis

Genetic susceptibility has been reported to be an important risk factor for peri-implant disease (PID). The aim of this meta-analysis was to assess the association between TNF-α and IL-10 polymorphisms and PID susceptibility. The Web of Science, Cochrane Library, Scopus, and PubMed/Medline databases were searched for studies published until 12 April 2021. RevMan 5.3, CMA 2.0, SPSS 22.0, and trial sequential analysis software were used. Twelve studies were included in our analysis. The pooled ORs for the association of TNF-α (−308 G > A), IL-10 (−1082 A > G), IL-10 (−819 C > T), and IL-10 (−592 A > C) polymorphisms were 1.12, 0.93, 1.35, and 0.77 for allelic; 1.42, 0.95, 3.41, and 0.34 for homozygous; 1.19, 1.88, 1.23, and 0.49 for heterozygous, 1.53, 1.12, 1.41, and 0.39 for recessive; and 1.16, 1.87, 2.65, and 0.75 for dominant models, respectively, with all the estimates being insignificant. The results showed an association between TNF-α (−308 G > A) polymorphism and the risk of PID in patients of Asian ethnicity (OR = 1.59; p = 0.03). The present meta-analysis illustrated that TNF-α (−308 G > A), IL-10 (−1082 A > G), IL-10 (−819 C > T), and IL-10 (−592 A > C) polymorphisms were not associated with the risk of PID, whereas TNF-α (−308 G > A) polymorphism was associated with an elevated risk of PID in Asian patients.

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.

Materials Sealing Preventing Biofilm Formation in Implant/Abutment Joints: Which Is the Most Effective? A Systematic Review and Meta-Analysis

The purpose of this systematic review was to evaluate the literature available for materials exhibiting the best efficacy in preventing biofilm formation in the interior of implants. We searched PubMed/MEDLINE, Scopus, and Cochrane databases. This review is registered with the PROSPERO database and followed the suitability of the PRISMA protocol. The initial search resulted in 326 articles from the databases. After they were read, 8 articles remained, and the inclusion and exclusion criteria were applied. Six of these 8 articles were classified as in vitro and 2 were classified as in situ. The regions of the implants evaluated ranged from the interface of the pieces to the occlusal upper access of the abutment. The implant connections evaluated the Morse taper, external connection, and internal connection. Meta-analysis of the quantitative data was performed at a significance level of .05. Cotton exhibited poor control of infiltration, even in combination with other materials. Isolated gutta-percha (GP) and polytetrafluoroethylene (PTFE) tape with composite resin (CR) or GP performed better as physical barriers. The best results for chemical barriers were observed by the application of 1% chlorhexidine gluconate (CG) gel, thymol varnish, and the deposition of Ag films onto the surface. The applied meta-analysis did not show a significant difference in comparison between the different types of implant connections (P > .05). The application of CG and thymol varnish antimicrobials was effective in preventing biofilm formation and easy clinical execution; these could be used in combination with CR, GP, and PTFE.

Identification of Disease Risk DNA Variations is Shaping the Future of Precision Health

In recent years, the knowledge generated by decoding the human genome has allowed groundbreaking genetic research to better understand genomic architecture and heritability in healthy and disease states. The vast amount of data generated over time and yet to be generated provides the basis for translational research towards the development of preventive and therapeutic strategies for many conditions. In this special issue, we highlight the discoveries of disease-associated and protective DNA variations in common human diseases and developmental disorders.

The relationship between single nucleotide polymorphisms and dental implant loss: a scoping review

OBJECTIVES

The purpose of this review was to evaluate the relationship between genetic polymorphisms and dental implant loss.

MATERIALS AND METHODS

All case-control studies examining single nucleotide polymorphisms (SNPs) and dental implant failure were considered. A Boolean search was conducted on PubMed and Scopus to find eligible studies.

RESULTS

The initial search produced 78 results. Twenty-one studies were considered for inclusion after review and 16 were included in the final review. Twenty-two different polymorphisms were analyzed and statistically significant correlation was found for IL-4, IL-1A, IL-1B, MMP-8, and MMP-1 polymorphisms for dental implant failure.

DISCUSSION

A limited number of comprehensive studies have been done in this field. Additional studies with larger sample sizes and different ethnic backgrounds need to be done to see if the results can be reproduced. Of the polymorphisms studied, the IL-4 (+33), MMP-8 (-799), MMP-1 (-519), and MMP-1 (-1607) polymorphisms show the greatest association with dental implant loss.