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Influence of titanium-base and universal abutment heights on the adaptation and fracture of screw-and-cemented-retained lithium disilicate crowns

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Author(s):
de Oliveira, Aline Cristina ; Strazzi-Sahyon, Henrico Badaoui ; Maluly-Proni, Ana Teresa ; de Marchi, Ana Luiza ; Assuncao, Wirley Goncalves ; dos Santos, Paulo Henrique ; Margonar, Rogerio
Total Authors: 7
Document type: Journal article
Source: JOURNAL OF PROSTHODONTIC RESEARCH; v. N/A, p. 9-pg., 2025-09-10.
Abstract

Purpose: This in vitro study evaluated the adaptation and fracture resistance of screw- and cement-retained implant-supported restorations using lithium disilicate crowns cemented onto titanium bases and universal abutments of different heights. Methods: Thirty crowns were designed, milled, and divided into three groups: TBA (titanium base abutment - 4.7-mm-height and 4.65-mm-diameter), UA-4 (universal abutment - 4.0-mm-height and 4.5-mm-diameter), and UA-6 (universal abutment - 6.0-mm-height and 4.5-mm-diameter) (n=10). The abutments were placed in a mandibular first premolar model, torqued to 20 Ncm, and scanned using a digital intraoral scanner. The crowns were designed and fabricated using computer-aided design/computer-aided manufacturing technology. Adaptation was assessed using a stereomicroscope before and after ceramic sintering and after cementation with RelyX Ultimate resin cement. Fracture resistance was evaluated using a universal testing machine, and the failure modes were analyzed. The collected data were subjected to statistical analysis using one-way ANOVA and the Tukey least significant difference test (alpha=0.05). Results: The abutment type influenced restoration adaptation and fracture resistance. No differences in adaptation were found before or after luting (P > 0.05). However, after sintering, the TBA group exhibited smaller marginal gaps than the UA-4 (P = 0.0339) and UA-6 (P = 0.0006) groups. TBA showed a higher fracture resistance than UA-4 (P = 0.0093); no differences were observed between TBA and UA-6 or between UA-4 and UA-6 (P > 0.05). The UA-4 and UA-6 groups showed higher ceramic fracture rates, whereas the TBA group showed increased abutment deformation and ceramic fractures. Conclusions: The type and height of abutments influenced the fracture of screw-and-cement-retained implant-supported restorations. (AU)

FAPESP's process: 22/12118-5 - Development of the recycling process of 3Y-TZP and application in the production of composites with elastic module gradients
Grantee:Henrico Badaoui Strazzi Sahyon
Support Opportunities: Scholarships in Brazil - Post-Doctoral