A Retrospective Study of Sintered Porous-Surfaced Dental Implants in Restoring the Edentulous Posterior Mandible: Up to 9 Years of Functioning

Impact of splinting implant-supported crowns on the performance of adjacent posterior implants: A systematic review and meta-analysis

STATEMENT OF PROBLEM

While rehabilitation with implant-supported crowns in the posterior region is widely practiced, guidance on clinical considerations when choosing between splinted or nonsplinted implant-supported crowns is limited.

PURPOSE

The purpose of this systematic review with meta-analysis was to assess whether adjacent implants with internal connections in the posterior region should be treated with splinted or nonsplinted crowns.

MATERIAL AND METHODS

The systematic review was registered on the prospective register of systematic reviews (PROSPERO) under the code, CRD42021248525. Two authors searched 4 electronic databases (PubMed, Cochrane Library, Scopus, and Web of Science) independently for articles published up to December 2023. Additionally, a hand search was conducted in the nonpeer-reviewed literature and the reference lists of included articles. Only clinical studies comparing splinted and nonsplinted hexagonal or conical internal connection adjacent implants in the posterior region were considered. A single-arm meta-analysis was conducted using RevMan. Risk of bias and quality were assessed using the Cochrane Collaboration's Tool for Assessing Risk and the Newcastle-Ottawa scale.

RESULTS

Qualitative synthesis included 17 studies, and quantitative synthesis involved 13 studies. A total of 2085 implants (1244 splinted and 841 nonsplinted) were inserted in 1027 participants, with observation times ranging from 5 months to 16 years. Thirteen studies related the type of crown retention (cemented or screw-retained). Only 2 studies related annual bone loss results considering the type of crown retention, but whether they were splinted or nonsplinted crowns and significant differences were not specified. The meta-analysis revealed no statistical differences between splinted and nonsplinted implants for biological complications (P=.95, I2=0%). However, the nonsplinted implants exhibited significantly more mechanical complications than the splinted implants (P<.001, I2=1%, RR 0.37; 95% IC [0.26-0.54]). The studies included demonstrated a low risk of bias and were of good quality.

CONCLUSIONS

Splinting was not found to affect the incidence of biological complications in posterior adjacent implants. However, more mechanical complications occurred in nonsplinted crowns than splinted ones.

A comparison of marginal bone loss, survival rate, and prosthetic complications in implant-supported splinted and nonsplinted restorations: A systematic review and meta-analysis

Aim

To compare marginal bone loss (MBL), implant survival rate and prosthetic complications of implant-supported splinted and non-splinted restorations (NSR).

Settings and Design

This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines (PRISMA). The PROSPERO registry, which keeps track of prospective systematic reviews, also received this paper (CRD42021229477).

Material and Methods

An electronic search was done in PubMed, the Cochrane Central Trials Register, Scopus, Science Direct, and Google Scholar searches were carried out. The search was limited to articles published in English and covered the period from January 2010 to August 2020.

Statistical Analysis Used

To conduct the meta analysis, researchers employed methodologies such as continuous measurement and odds ratios.

Results

For both qualitative and quantitative analysis, 19 scientific studies were chosen. 3682 implants were placed in 2099 patients with a mean age of 59 years (splinted, 2529; non-splinted, 1153); the mean age was not provided in 5 trials. For splinted restorations, there were statistically significant differences in MBL, indicating the former has less MBL than for NSR. Splinted restorations had much greater survival rates than NSR, according to a qualitative study. Rest prosthesis complications with or without splinting were essentially the same.

Conclusions

Splinted implant restorations lost less bone than non-splinted implant restorations, according to this meta analysis. This was particularly true for posterior restorations. Lower implant failure was associated with splinted restorations. Restorations with and without splinting had the same level of prosthetic problems.

Survival Rates of Splinted and Nonsplinted Prostheses Supported by Short Dental Implants (≤8.5 mm): A Systematic Review and Meta-Analysis

PURPOSE

To evaluate and compare the implant survival rates, marginal bone loss, and mechanical complications of prostheses supported by splinted and nonsplinted short implants (≤8.5 mm).

MATERIAL AND METHODS

Electronic database (MEDLINE, CENTRAL, Web of Science, and EMBASE) and manual searches up to May 2021 were conducted to identify studies comparing splinted and nonsplinted short implants (≤8.5 mm). The primary outcome was implant survival rate. Secondary outcomes were marginal bone loss and mechanical complications. The quality of included studies and risk-of-bias were assessed according to the Newcastle-Ottawa Scale. A random-effects model was used to analyze the data.

RESULTS

Twelve studies fulfilled the inclusion criteria and featured 1506 short implants (596 nonsplinted and 910 splinted) with a follow-up time ranging from 1 to 16 years. Quantitative analysis found no statistically significant differences between splinted and nonsplinted short implants (≤8.5 mm) for survival rate (RR = 0.98; 95% CI 0.96, 1.01; p = 0.26)) and marginal bone loss (SMD = -0.08; 95% CI - 0.23, 0.07; p = 0.28). Veneer chipping, abutment screw breakage, screw loosening, and loss of retention were reported in the selected studies as common complications. However, no statistically significant difference was found between splinted and nonsplinted short implants (RR = 0.56; 95% CI 0.20, 1.54; p = 0.26).

CONCLUSIONS

Within the limitations of the present meta-analysis, it might be concluded that splinted short implants (≤8.5 mm) do not present superior performance in survival rate, marginal bone maintenance and prevention of mechanical complications compared with single-unit prostheses.

Effect of crown-to-implant ratio on the marginal bone level changes and implant survival - A systematic review and meta-analysis

The purpose of the systematic review and meta-analysis was to analyze the existing evidence regarding the effect of crown-to-implant ratio (CIR) on the peri-implant crestal bone level change and implant survival. Randomized controlled clinical trials, prospective as well as retrospective studies with a minimum follow-up period of 12 months and 10 patients per group were included for this systematic review. Statistical analysis was performed to determine CIR effects on the peri-implant marginal bone level changes and implant survival. A total of 28 articles (14 prospective studies and 14 retrospective studies) from a database of 201 articles, with 2097 patients and 4350 implants, were included. A mean CIR ranging from 0.6 to 2.44 was presented by the study groups. A weighted mean implant loss of 0.19% per year and peri-implant marginal bone level change of 0.63 mm ± 0.55 over 46.8 ± 5.2 months was calculated from the included studies. The peri-implant marginal bone level change (p = 0.155) and the rate of implant loss (p = 0.245) showed a statistically insignificant difference between implant restorations of a high (>1.5:1) and low (<1.5:1) CIR. Within its limitations, this review concludes that a high (>1.5:1) or a low (<1.5:1) CIR does not significantly affect the peri-implant marginal bone level change and implant survival rate. However, until further evidence becomes available, extrapolation to long term clinical success cannot be ascertained.

Load-carrying capacity of short implants in edentulous posterior maxilla: A finite element study

Dental implant dimensions, and bone quality and quantity play a key role in early osseointegration and long-term prognosis in posterior edentulous maxilla. Treatment with short implants, preferably in a bicortical manner, is an accepted modality; however, short implants have limitations leading to increased stress concentrations in alveolar bone, potential overload and implant failure. Implant models of 3.3, 4.1, 4.8 and 5.4 mm diameter and 4.5, 5.5, 6.5, 7.5 and 8.5 mm length were placed in posterior maxilla 3-D models with corresponding residual bone heights. Bone-implant assemblies were analyzed in finite element software ANSYS 15. All materials were assumed to be linearly elastic and isotropic. 118.2 N oblique loading was applied to investigate stress distributions in bone tissues. The concept of ultimate functional load (UFL) was selected as a criterion to compare load-carrying capacity of implants and to evaluate the influence of available bone height and implant dimensions on load-carrying capacity. For all implants, UFL was calculated by limiting von Mises stresses in cortical or cancellous bone with bone strength (100 MPa for cortical and 2 MPa for cancellous bone). Implant load-carrying capacity depends on diameter and available bone height. Wide implants have higher load-carrying capacity than narrow implants. Short implants with proper diameter and length avoid bone overstress, even in Type IV bone.

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.

Technical and biological complications related to crown to implant ratio: a systematic review

AIM

To review the occurrence of prosthetic failure and biological complications with respect to the crown to implant (C/I) ratio.

METHODS

Accurate search was made on the subject C/I ratio with the following criteria: (1) studies on humans with data on prosthetic failure and/or biological complications related to C/I ratio; (2) partial edentulous patients; (3) randomized clinical trials, prospective, longitudinal, retrospective, and multicenter studies with a minimum of 48 months mean follow-up; (4) language: English; (5) radiographic measurements by peri-apical x-ray; (6) implant material: titanium; and (7) no implant type selection was applied.

RESULTS

Six articles were considered eligible for full-text analysis. Unfavorable C/I ratio can be considered a potential risk factor for single crown and abutment loosening (C/I ratio ≥ 1.46) and abutment fractures in posterior areas (C/I ratio ≥ 2.01).

CONCLUSIONS

Despite the limited data, high C/I ratio may be related to some prosthetic failures. Unfavorable C/I ratio does not affect biological complications and implant failure.

Systematic review of the survival rate and the incidence of biological, technical, and aesthetic complications of single crowns on implants reported in longitudinal studies with a mean follow-up of 5 years

OBJECTIVE

To assess the 5-year survival of implant-supported single crowns (SCs) and to describe the incidence of biological, technical, and aesthetic complications. The focused question was: What is the survival rate of implants supporting single crowns and implant-supported crowns with a mean follow-up of 5 years and to which extent do biological, technical, and aesthetic complications occur?

METHODS

A Medline search (2006-2011) was performed for clinical studies focusing on implant-supported SCs with a mean follow-up of at least 5 years. The search was complemented by an additional hand search and the inclusion of 24 studies from a previous systematic review (Jung et al. 2008a). Survival and complication rates were analyzed using random-effects Poisson's regression models to obtain summary estimates of 5- and 10-year proportions.

RESULTS

Forty-six studies derived from an initial search count of 1083 titles and the complementary publications from the previous systematic review (Jung et al. 2008a) were selected and the data were extracted. Based on the meta-analysis, survival of implants supporting SCs at 5 years amounted to 97.2% (95% CI: 96.3-97.9%), and at 10 years amounted to 95.2% (95% CI: 91.8-97.2%). The survival of implant-supported SCs was 96.3% (95% CI: 94.2-97.6%) after 5 years and 89.4% (95% CI: 82.8-93.6%) after 10 years. For biological complications, a 5-year cumulative soft tissue complication rate of 7.1% (95% CI: 4.4-11.3%) and a cumulative complication rate for implants with bone loss >2 mm of 5.2% (95% CI: 3.1-8.6%) were calculated. Technical complications reached a cumulative incidence of 8.8% (95% CI: 5.1-15.0%) for screw-loosening, 4.1% (95% CI: 2.2-7.5%) for loss of retention, and 3.5% (95% CI: 2.4-5.2%) for fracture of the veneering material after 5 years. The cumulative 5-year aesthetic complication rate amounted to 7.1% (95% CI: 3.6-13.6%).

CONCLUSIONS

The outcomes of the meta-analysis demonstrated high implant survival rates for both the single tooth implants and the respective single crowns after 5 and 10 years. However, technical, biological, and aesthetic complications were frequent.