Análise da rugosidade de superfície de resinas de provisórios em prótese fixa

Abstract

INTRODUCTION: During prosthetic treatment, provisional restorations play a fundamental role, allowing aesthetics, function and comfort to be assessed before the definitive prostheses are fitted. The resins used in provisionals can be acrylics such as polymethylmethacrylate (PMMA), bis-acrylic resins or the new CAD/CAM resins (milling or 3D printing). The average roughness (Ra) of the surface of provisional restorations is an important physical property, as it influences adhesion and the accumulation of microbial plaque. Rougher surfaces are more prone to biofilm formation, which can result in inflammation in the gingival tissues and the development of caries in the abutment teeth. The main objective of this laboratory study was to determine the Ra of different types of resin used to make provisional fixed prostheses. METHODOLOGY: Twenty square specimens were made, 5 of each type of resin (PMMA (Tab 2000, Kerr®, Switzerland), bis-acrylic resin (Structur 3, VOCO®, Germany), milling resin (Structur CAD, VOCO®, Germany) and 3D printing resin (Dental Sand, Harz Labs, Russia)). The 20 standardized specimens (20x20x2mm) were subjected to the same polishing protocol using 3MTM Sof-LexTM discs. The Ra was assessed at 6 different locations on the specimens with a contact profilometer and the mean was recorded. The data obtained was subjected to descriptive and inferential statistical analysis at a significance threshold of p<0.05. RESULTS: The lowest Ra values were recorded in the milling resin (0.303µm) and the highest in the bis-acrylic resin (0.686µm), with statistically significant differences (p=0.000). Statistically significant differences were also found between milling and 3D printing resins (p=0.004) and between acrylic and bis-acrylic resins (p=0.011). On the other hand, the printed and bis-acrylic resins (p=0.183), as well as the milled and PMMA (p=0.087) and the PMMA compared to the printed resin (p=1) did not differ significantly. CONCLUSION: Due to its lower average roughness value, we can consider milling resin to be a good clinical option for long-term provisionals. Although more scientific evidence is needed, based on the results obtained, the use of bis-acrylic resin is not recommended for this type of provisional fixed restoration.

Date of Award	9 Jul 2025
Original language	Portuguese
Awarding Institution	Universidade Católica Portuguesa
Supervisor	Helena Salgado (Supervisor), Patrícia Fonseca (Co-Supervisor) & Carlos Miguel da Costa Gomes Fernandes (Co-Supervisor)