Complete Edentulous Rehabilitation Using an Immediate Function Protocol and an Implant Design Featuring a Straight Body, Anodically Oxidized Surface, and Narrow Tip with Engaging Threads Extending to the Apex of the Implant: A 5-year Retrospective Clinical Study

Prosthetic complications and failures of implant-supported fixed partial dentures: A scoping review

STATEMENT OF PROBLEM

Although high survival rates of implant-supported fixed partial dentures (ISFPDs) have been reported, evidence for complications, failures, and factors that interfere with their longevity is lacking.

PURPOSE

The purpose of this scoping review was to review the literature to investigate the most common failures and complications of ISFPDs.

MATERIAL AND METHODS

This review followed the preferred reporting items for systematic reviews and meta-analyses scoping review (PRISMA ScR) guidelines, and the methodology was registered on the open science framework (osf.io/5xqkp). An electronic search was conducted in PubMed/MEDLINE, Embase, Cochrane Library, Scopus, and Web of Science databases and nonpeer-reviewed literature for articles published from 2013 to January 2023. Studies that evaluated the clinical performance of ISFPDs with at least 1 year of follow-up and described the concepts of failure and success were included.

RESULTS

The search yielded 5695 studies. Fourteen articles were included in this review for data extraction. Veneering porcelain fracture, screw fracture, and implant loss were the most common failures reported. Technical complications mainly involved screw loosening, loss of retention, and wear of the screw-access restoration.

CONCLUSIONS

Bruxism, mismatch of the thermal expansion coefficient, unsatisfactory support of the framework, choice of cement, shape of the titanium abutments, and extended length of the cantilever were associated with the longevity of the ISFPD. Despite the high survival rate of ISFPDs, data must be carefully interpreted because of the variation in the materials used to manufacture the ISFPD and the heterogeneity of the studies in this review.

Marginal bone level change during sequential loading periods of partial edentulous rehabilitation using immediately loaded self-tapping implants: a 6.5-year retrospective study

PURPOSE

A large number of studies have suggested the practicability and predictability of immediate implant function, but few studies have reported marginal bone level changes during sequential loading periods. The purpose of this study was to evaluate the marginal bone remodeling of immediately loaded self-tapping implants both at each time point and during each loading period between two time points.

MATERIALS AND METHODS

The patients included in this retrospective study were treated with immediately loaded NobelSpeedy Replace implants between August 2008 and July 2009. Differences in the marginal bone level (MBL) at each time point and the marginal bone level change (ΔMBL) between two time points were analyzed with Bonferroni correction (P < .05).

RESULTS

Overall, 24 patients (mean age, 47.3 ± 12.8 years) with 42 immediately loaded implants and a median follow-up of 6.5 years (IQR, 67.8 months) were included. The cumulative survival rate after 10 - 12 years was 95.2%. Continuous but slow marginal bone loss was observed during long-term follow-up. MBL at both 7.5 years and 11 years was significantly lower than that at loading, 6 months, 2 years and 4 years (P < .05). No bone loss difference was found in any period before 4 years of follow up (P > .05). The loading period of 4 years to 7.5 years showed the largest ΔMBL compared to those of other time periods (P < .05).

CONCLUSION

Slight bone loss occurred continuously, and more radical changes of marginal bone can be observed during the period of 4-7.5 years. Thus, long-term effective follow-up of immediately loaded implants is needed.

Immediate Maxillary Full-Arch Rehabilitation of Periodontal Patients with Terminal Dentition Using Tilted Implants and Bone Augmentation: A 5-Year Retrospective Cohort Study

Background: All-on-four protocols with tilted implants in the maxilla are used to rehabilitate the terminal dentition of the severe generalized periodontitis patients. Data on long-term biological complications are scarce. Methods: Eighty-four axial and forty-six tilted immediate implants have been placed in the extraction sockets of 23 patients according to a four–six implants protocol combined with ridge augmentation. Within 72 h, a provisional prosthesis was cemented to the implants; after 6 months, a cemented ceramic–metallic prosthesis was delivered. The patients were followed for up to 5 years. Results: The 5-year survival rate of the straight and tilted implants was 100% and 97.8, and the prosthetic one was 100%. Marginal bone loss (MBL) of the straight implants was 0.42 ± 0.67 and 0.59 ±1.01 mm on the mesial and distal sides; for the tilted, it was 0.37 ± 0.68 and 0.34 ±0.62 mm, and the differences were not statistically significant. Implant position, smoking, keratinized mucosal width, and cantilever did not affect MBL. Peri-implant mucositis involved 29.4% and 22.2% of the straight and tilted implants, respectively; peri-implantitis involved 5.8% and 4.4% of the straight and tilted implants, respectively, without statistical significance. Conclusions: This immediate loading protocol’s 5-year survival and success rates were high. No difference between the straight and tilted implants was found regarding survival, success rates, and MBL.

Does the natural maxillary dentition influence the survival rate of mandibular metal-resin implant-supported fixed complete dentures? A systematic review and meta-analysis

STATEMENT OF PROBLEM

Consensus is lacking regarding the influence of the maxillary dentition on the survival rate of a mandibular metal-resin implant-supported fixed complete denture (MRISFCD) with distal cantilevers.

PURPOSE

The purpose of this systematic review was to identify whether an opposing natural dentition influences the survival rate of mandibular MRISFCDs.

MATERIAL AND METHODS

A literature search was performed up to February 2018 from MEDLINE/PubMed, Scopus, Web of Science, Cochrane Library, BBO/LILACS databases and also in the non-peer-reviewed literature through Open Grey. Clinical studies regarding natural (ND), removable prostheses (RP), and complete fixed maxillary implant dentitions (ID) with at least a year of follow-up were included. The quality of the included studies was analyzed, and the risk of bias was reported. A meta-analysis comparing the survival rate of ND with RP and ND with ID was performed with a confidence interval (CI) of 95%, and heterogeneity was tested by an I² index. Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach was used to determine the certainty of the evidence.

RESULTS

From a total of 112 ND, 69 ID, and 204 RP in the maxillary dentition, the overall prevalence of failures was 5.4% (6/112; 95% CI [2.3 to 10.76]) for ND, 13.99% (20/69; 95% CI [0.77 to 39.41]) for ID, and 4.9% (10/204; 95% CI [0.69 to 12.18]) for RP. No statistical differences were detected in the success rates between ND and RP (risk difference = 0.00 [-0.06, 0.06]; P=.93; I²=27%) or between ND and ID (risk difference=0.00 [-0.06, 0.07]; P=.97; I²=0%), both with moderate evidence.

CONCLUSION

With a moderate certainty of evidence, it is suggested that natural maxillary dentitions do not affect the survival rate of mandibular MRISFCDs differently from other prosthetic designs.

Biological and mechanical complications of angulated abutments connected to fixed dental prostheses: A systematic review with meta-analysis

OBJECTIVES

To evaluate the biological and mechanical complications of angulated abutments on full-arch and partial jaw rehabilitations with a follow-up for at least 1 year.

METHODS

Electronic search was carried out in MEDLINE, EMBASE and Web of Science. Studies published between January 2000 and January 2019 were included. The quality of the included studies was assessed. The data extraction was focused on implant loss, marginal bone loss and mechanical complications, and meta-analyses were performed for marginal bone loss, mechanical complications and implant failure.

RESULTS

Nine studies, three prospective and six retrospective cohort studies were included. They reported on 797 patients that received 4127 implants. The total number of abutments was 4079 of which 1673 were angulated, and 2406 were straight. All abutments were prefabricated. Angulated abutments were associated with increased implant failure rates (two studies; RR = 7.30; 95% CI = 2.79-19.08) and an effect that was both statistically significant (P < .001) and clinically relevant. Three studies reported differentiated data for mechanical and technical complications at 1 year of follow-up, being mostly related to the retention screw while screw fracture. Angulated abutments were associated with a statistically significant increase in MBL 1 year after insertion compared to straight abutments (three studies; MD = 0.08 mm; 95% CI = 0.01-0.14 mm; P = .02), which might be, however, clinically negligible.

CONCLUSIONS

The prosthetic complications such as screw loosening and abutment loosening were frequent. After 1 year of follow-up, implants supporting angulated abutments yielded significantly more marginal bone loss than those supporting straight abutments.

Minimizing the discrepancy between implant platform and alveolar bone for tilted implants with a sloped implant platform: A clinical report

In a patient with edentulism, distally tilted implants with a novel sloped implant platform were used to minimize the discrepancy between the implant platform and alveolar bone crest and to restore complete-arch monolithic zirconia implant-supported fixed prostheses.

Retrospective 2- to 7-Year Follow-Up Study of 20 Double Full-Arch Implant-Supported Monolithic Zirconia Fixed Prostheses: Measurements and Recommendations for Optimal Design

PURPOSE

To measure the extension of cantilever lengths, thicknesses, and heights of zirconia prostheses in the lingual and facial areas of the distal screw access openings, and to evaluate the clinical performance regarding chipping or fracture of the distal cantilevered sections of double full-arch CAD/CAM screw-retained, stained, monolithic zirconia, gingival-colored ceramic implant-supported fixed prostheses (MZ-FPs).

MATERIALS AND METHODS

Ten edentulous patients were provided with a total of 20 CAD/CAM double full-arch MZ-FPs. The zirconia thicknesses around distal screw access openings at three different levels (crown height space, screw access opening lengths, and dimensions of the cantilevered segments) were measured in the resin prototypes. Patients were evaluated clinically (visually) without magnification, with intraoral digital photography, and radiologically by the author, approximately every 6 months. Ten patients with 20 MZ-FPs were evaluated. Twenty resin prototypes with 35 cantilevered segments (15 maxillary, 20 mandibular) were measured. The lingual and facial thicknesses of the resin frameworks and the crown height spaces of 35 distal access openings were measured.

RESULTS

The average extension of the maxillary cantilever segments was 7.72 mm; the mandibular cantilever average was 13.72 mm. The average crown height space for maxillary prostheses was 13.27 mm, for the mandibular prostheses it was 11.89 mm. Zirconia thickness around distal screw access openings at the middle of the crowns, margins and middle of the gingival areas (buccal side of maxillary prostheses) was 4.29, 3.79, and 3.87 mm, respectively. On the lingual sides the thicknesses were 3.13, 2.85, and 3.15 mm, respectively. For mandibular prostheses the thicknesses were 3.56, 3.08, and 3.15 mm, respectively, on the buccal sides, and 2.07, 2.00, and 2.99 mm, respectively, on the lingual sides. No implant failure or changes in the occlusal surface, chipping of the cuspid or incisal edges, or prosthesis distal extension fractures were observed during follow-up periods ranging from 2 to 7 years. The survival rate was 100% for implants and prostheses. In one of the patients, chipping of the pink ceramic was noted in the maxillary prosthesis 36 months after placement.

CONCLUSIONS

The results of this study indicated that full-arch MZ-FPs without cutback, or with partial digital cutback and veneering ceramic, were a therapeutic option. Recommendations regarding the thickness of zirconia at the level of the distal screw access openings, the crown height spaces, and the lengths of the cantilever segments were recorded. Additional in vitro and clinical studies will be required for more scientific analysis of the criteria for design of this type of prosthesis to minimize prosthetic complications. Long-term and multicenter studies are needed to corroborate the findings discussed in this report.