Long-term retrospective clinical study of tooth-supported fixed partial dentures: A multifactorial analysis

Fracture strength of 3-units fixed partial dentures fabricated with metal-ceramic, graphene doped PMMA and PMMA before and after ageing: An in-vitro study

OBJECTIVES

To evaluate the fracture strength and linear elongation at break of three-units fixed partial dentures (FPDs) fabricated with traditional and new materials for fixed prosthodontics before and after ageing.

METHODS

Sixty models of three-units FPDs were fabricated and cemented onto a Co-Cr model simulating the replacement of a maxillary second premolar. The samples were randomly divided into 3 groups: metal-ceramic (MCR), graphene-doped polymethylmethacrylate (PMMA-GR) and polymethylmethacrylate (PMMA). Half of the samples were directly subjected to fracture test, while the remaining half underwent an ageing process and then a fracture loading test using an electrodynamic testing machine. Fracture load and elongation at break values were taken and statistically analysed.

RESULTS

Significant differences were detected between the different materials (p<0.05). All groups showed a reduction of the fracture load and elongation at break values after ageing, but not statistically significant, except for PMMA group (p = 2.012e-19) (p = 3.8e-11).

CONCLUSIONS

MCR and PMMA-GR three-units FPDs showed higher fracture strength and lower elongation at break compared to PMMA. MCR and PMMA-GR had higher resistance to ageing processes compared to PMMA.

CLINICAL SIGNIFICANCE

PMMA-GR could be considered a material for long-term provisional restorations as its mechanical behaviour and ageing resistance are more like MCR than PMMA.

Implant-assisted removable partial dentures: Part II. a systematic review of the effects of implant position on the biomechanical behavior

PURPOSE

This systematic review aimed to evaluate the effects of implant placement sites on the biomechanical behavior of implant-assisted removable partial dentures (IARPDs) using finite element analysis (FEA).

STUDY SELECTION

Two reviewers independently conducted manual searches of the PubMed, Scopus, and ProQuest databases for articles investigating implant location in IARPDs using FEA, according to the 2020 Systematic Reviews and Meta-analyses statement. Studies published in English up to August 1, 2022, were included in the analysis based on the critical question.

RESULTS

Seven articles meeting the inclusion criteria were systematically reviewed. Six studies investigated mandibular Kennedy Class I and one study investigated mandibular Kennedy Class II. Implant placement reduced the displacement and stress distribution of the IARPD components, including dental implants and abutment teeth, regardless of the Kennedy Class type and dental implant placement site. Most of the included studies showed that, based on the biomechanical behavior, the molar region, rather than the premolar region, is the preferred implant placement site. None of the selected studies investigated the maxillary Kennedy Class I and II.

CONCLUSIONS

Based on the FEA regarding mandibular IARPDs, we concluded that implant placement in both the premolar and molar regions improves the biomechanical behaviors of IARPD components, regardless of the Kennedy Class. Implant placement in the molar region results in more suitable biomechanical behaviors compared with implant placement in the premolar region in Kennedy Class I. No conclusion was reached for Kennedy Class II due to the lack of relevant studies.

Clinical outcomes of tooth-supported monolithic zirconia vs. porcelain-veneered zirconia fixed dental prosthesis, with an additional focus on the cement type: a systematic review and meta-analysis

PURPOSE

To compare the failure rates and the prevalence of technical complications between full-coverage tooth-supported monolithic zirconia (MZ) and porcelain-veneered zirconia (PVZ) fixed dental prosthesis, based on a systematic literature review.

METHODS

An electronic search was performed in three databases, supplemented by hand searching. Several statistical methods were used.

RESULTS

Seventy-four publications reported 6370 restorations (4264 PVZ; 2106 MZ; 8200 abutment teeth; 3549 patients), followed up until 152 months. A total of 216 prostheses failed, and survival was statistically significant different between groups. PVZ had higher occurrence of complications than MZ; the difference was especially greater for either minor or major chipping. The difference in prevalence of either minor or major chipping was statistically significant for PVZ prostheses between cementation with glass ionomer and adhesive resin cement (higher), adhesive resin and resin-modified glass ionomer cement (RMGIC, higher), and between RMGIC (higher) and glass ionomer cement. For MZ the difference was significant only for minor chipping between RMGIC (higher) and adhesive resin cement. Abutment teeth to PVZ prostheses more often lost vitality. Decementation was not observed with RMGIC. Air abrasion did not seem to clinically decrease the decementation risk. The 5-year difference in the occurrence of minor or major chipping between MZ and PVZ prostheses was statistically significant, but nor for catastrophic fracture.

CONCLUSION

Tooth-supported PVZ prostheses present higher failure and complication rates than MZ prosthesis. The difference in complications is striking when it comes to chipping.

CLINICAL RELEVANCE

Awareness of the outcome differences between different types of zirconia prostheses is important for clinical practice.

Technical complications with tooth-supported fixed dental prostheses (FDPs) of different span lengths: an up to 15-year retrospective study

BACKGROUNDS

Long-span dental bridges may cause excessive load on abutment teeth and the periodontal area, which may lead to bridge fractures or periodontal problems. However, some reports have revealed that short- and long-span bridges can provide a similar prognosis. This clinical study aimed to investigate the technical complications associated with fixed dental prostheses (FDPs) of different span lengths.

METHODS

All patients with previously cemented FDPs were clinically examined during their follow-up visits. Several data related to FDPs were registered, such as design, material type, location, and type of complication. The main clinical factors analyzed were technical complications. Life table survival analyses were performed to calculate the cumulative survival rate of FDPs when technical complications were detected.

RESULTS

The study examined 229 patients with a total number of 258 prostheses and an average of 98 months of follow-up. Seventy-four prostheses suffered from technical complications, and the most common complication was ceramic fracture or chipping (n = 66), while loss of retention occurred in 11 prostheses. The long-term evaluation of long-span prostheses revealed a significantly higher technical complication rate compared to short-span prostheses (P = ,003). The cumulative survival rate for short-span FDPs was 91% in year 5, 68% in year 10, and 34% in year 15. For long-span FDPs, the cumulative survival rate was 85% in year 5, 50% in year 10, and 18% in year 15.

CONCLUSION

Long-span prostheses (5 units or more) can be associated with a higher technical complication rate compared to short-span prostheses after long-term evaluation.

Oral and Periodontal Risk Factors of Prosthetic Success for 3-Unit Natural Tooth-Supported Bridges versus Implant-Supported Fixed Dental Prostheses

The goals of this research are: (1) to compare the survival and prosthetic success of metal-ceramic 3-unit tooth- versus implant-supported fixed dental prostheses; (2) to evaluate the influence of several risk factors on the prosthetic success of tooth- and implant-supported fixed dental prostheses (FPDs). A total of 68 patients with posterior short edentulous spaces (mean age 61.00 ± 1.325 years), were divided into two groups: 3-unit tooth-supported FPDs (40 patients; 52 FPD; mean follow-up 10.27 ± 0.496 years) and 3-unit implant-supported FPDs (28 patients; 32 FPD; mean follow-up 8.656 ± 0.718 years). Pearson-chi tests were used to highlight the risk factors for the prosthetic success of tooth- and implant-supported FPDs and multivariate analysis was used to determine significant risk predictors for the prosthetic success of the tooth-supported FPDs. The survival rates of 3-unit tooth- versus implant-supported FPDs were 100% and 87.5%, respectively, while the prosthetic success was 69.25% and 68.75%, respectively. The prosthetic success of tooth-supported FPDs was significantly higher for patients older than 60 years (83.3%) vs. 40-60 years old (57.1%) (p = 0.041). Periodontal disease history decreased the prosthetic success of tooth- versus implant-supported FPDs when compared with the absence of periodontal history (45.5% vs. 86.7%, p = 0.001; 33.3% vs. 90%, p = 0.002). The prosthetic success of 3-unit tooth- vs. implant-supported FPDs was not significantly influenced by gender, location, smoking, or oral hygiene in our study. In conclusion, similar rates of prosthetic success were recorded for both types of FPDs. In our study, prosthetic success of tooth- versus implant-supported FPDs was not significantly influenced by gender, location, smoking, or oral hygiene; however, history of periodontal disease is a significant negative predictor of success in both groups when compared with patients without periodontal history.