RESUMO

This case report focuses on the replacement of ceramic laminate veneers with suboptimal marginal fit and design, employing a digital workflow and CAD-CAM technology. The patient, a woman in her 30s, expressed concerns about the appearance and hygiene challenges of her existing veneers. A comprehensive assessment, including clinical examination, facial photographs and intraoral scanning, was conducted. Utilising CAD software, facial photographs and 3D models merged to create a digital wax-up, crucial in designing suitable veneers and addressing issues like overcontouring and a poor emergence profile. Following the removal of old veneers, a mock-up was performed and approved. Preparations ensured space for restorations with well-defined margins. The final restorations, milled with Leucite-reinforced vitreous ceramic, were cemented. At the 1 year follow-up, improved aesthetics, gingival health and functional restorations were observed. This report highlights the efficacy of digital workflows in achieving consistent and aesthetically pleasing outcomes in ceramic laminate veneer replacement.

Assuntos

Cerâmica , Desenho Assistido por Computador , Facetas Dentárias , Fluxo de Trabalho , Humanos , Feminino , Adulto , Estética Dentária , Planejamento de Prótese Dentária/métodos , Porcelana Dentária

RESUMO

Purpose: This study aimed to compare the risk of orthodontic mini-implant (OMI) failure between maxilla and mandible. A critical analysis of finite-element studies was used to explain the contradiction of the greatest clinical success for OMIs placed in the maxilla, despite the higher quality bone of mandible. Materials and Methods: Four tridimensional FE models were built, simulating an OMI inserted in a low-dense maxilla, control maxilla, control mandible, and high-dense mandible. A horizontal force was applied to simulate an anterior retraction of 2 N (clinical scenario) and 10 N (overloading condition). The intra-bone OMI displacement and the major principal bone strains were used to evaluate the risk of failure due to insufficient primary stability or peri-implant bone resorption. Results: The OMI displacement was far below the 50-100 µm threshold, suggesting that the primary stability would be sufficient in all models. However, the maxilla was more prone to lose its stability due to overload conditions, especially in the low-dense condition, in which major principal bone strains surpassed the pathologic bone resorption threshold of 3000 µstrain. Conclusions: The differences in orthodontic mini-implant failures cannot be explained by maxilla and mandible bone quality in finite-element analysis that does not incorporate the residual stress due to OMI insertion.