Tensile and Flexural Strength of Commercially Pure Titanium Submitted to Laser and Tungsten Inert Gas Welds

A five-year randomised controlled trial comparing zirconia-based versus metal-based implant-supported single-tooth restorations in the premolar region

OBJECTIVES

To compare 5-year biological, technical, aesthetic, and patient-reported outcomes of single-tooth implant-supported all-ceramic versus metal-ceramic restorations.

MATERIALS AND METHODS

Thirty patients with 63 premolar agenesis participated in the 5-year follow-up. The prosthetic treatment on single-tooth implants were randomly assigned to all-ceramic crowns on zirconia abutments (AC=31) or metal-ceramic crowns on metal abutments (MC=32). All patients were recalled to clinical examinations at baseline, 1, 3, and 5 years after prosthetic treatments. Biological, technical, and aesthetic outcomes including complications, were clinically and radiographically registered. The patient-reported outcomes were recorded using OHIP-49 questionnaire before treatment and at each follow-up examination.

RESULTS

At 5-year examination, the survival rate was 100% for implants and 100 % for AC and 97% for MC crowns and abutments. The marginal bone loss after 5-years was minor and not significantly different (p= 0.056) between AC (mean: 0.3, SD: 1.1) and MC restorations (mean: -0.1, SD: 0.4). The success rate of the implants based on marginal bone loss was 77.4% for AC- and 93.7% for MC-restorations. The marginal adaptation was significantly better for MC than for AC restorations (p=0.025). The aesthetic outcomes and patient-reported outcomes between AC and MC restorations were not significantly different.

CONCLUSIONS

The biological, aesthetic and patient-reported outcomes for implant-supported AC and MC restorations were successful and with no significant difference after 5-years. The marginal adaptation of the MC crowns cemented on titanium abutments showed significantly better fit than restorations based on zirconia crowns cemented on zirconia abutments.

Network meta-analysis of survival rate and complications in implant-supported single crowns with different abutment materials

OBJECTIVES

To compare the survival rate of abutments, marginal bone loss and peri-implant soft tissue discoloration among implant-supported single crowns with different abutment materials.

DATA

Randomized controlled trials (RCTs), controlled clinical trials, and cohort studies of implant-supported single crowns with different dental abutment materials.

SOURCES

A systematic search was conducted by an electronic search in 6 databases without restrictions on September 16, 2018, complemented by a manual search. "Grey" literatures were also searched.

STUDY SELECTION

Of 3417 studies initially retrieved, thirteen were eligible for inclusion. After studies selected and data extraction, pair-wise and network meta-analyses were performed to analyze the survival rate of the abutment, the marginal bone loss and the soft tissue discoloration. The risk of bias was assessed based on the Cochrane guidelines, Newcastle-Ottawa scale, and funnel plots. Statistical heterogeneity, inconsistencies, and cumulative ranking were also evaluated.

RESULTS

Fourteen RCTs and nine non-RCTs were included. No significant differences was detected among titanium (Ti), zirconia (Zr), gold (Au), and alumina (Al) abutments in terms of survival rate (excluding Al < Ti (P < 0.05), marginal bone loss (excluding Zr  < Ti (P < 0.05) and Au  > Zr (P < 0.05)), or discoloration of peri-implant soft tissue. Additionally, Ti abutment had the highest cumulative ranking of survival rate (97.9%); Al abutment had the lowest marginal bone loss (81.4%) and Zr abutment had the least discoloration of peri-implant soft tissue (84.8%).

CONCLUSIONS

Ti abutment has a comparable survival rate with Zr, but better than Al. In addition, Zr abutment has a better effect in maintaining the marginal bone level, compared with Au and Ti. However, there was no difference in the discoloration of peri-implant soft tissue among Au, Ti, and Zr abutment.

CLINICAL SIGNIFICANCE

Based on the results of our network meta-analysis, Zr might be a recommended abutment material considering the clinical efficacy of implant-supported single crowns.