A New Proposal for Calibrated Gauges for Removable Partial Dentures: A Finite Element Analysis.

AIM: The aim of this study was to evaluate the stress distribution of a planned removable partial denture (RPD) using new proposals for calibrated gauges of 0.3 mm and 0.35 mm undercuts through the three-dimensional (3D) finite element methodology, and compare them with 0.25 mm and 0.5 mm gauges that are already existing in clinical practice. MATERIALS AND METHODS: Kennedy class-I edentulous 3D models and their respective RPDs (InVesalius software; Rhinoceros and SolidWorks CAD) were created and exported to the finite element program HyperMesh 2019 for mesh configuration. In the following steps, axial loading (0º) of 40 N per point was performed, with 3 points on the molars and 2 points on the premolars, totaling 280 N unilaterally. The model was processed by the OptiStruct 2019 software and imported into the HyperView 2019 software to obtain the stress maps (MPa). RESULTS: The use of 0.30 and 0.35 mm calibrated gauges presented tensions similar to those with the 0.25 mm gauge (gold standard) and caused no significant damage to biological structures. The use of a 0.5 mm undercut caused greater traction force in the periodontal ligament of the abutments. CONCLUSIONS: The 0.35 mm undercut seems promising as it presented more favorable results in this simulation, on the other hand, a 0.5 mm undercut is greater than that necessary for retainers made of CoCr. CLINICAL SIGNIFICANCE: This study aims to measure a new undercut gauge (0.35 mm) to increase the retention area in abutment teeth of removable partial dentures.

Development of 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methyl-morpholinium chloride cross-linked carboxymethyl cellulose films.

First example of the use of 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methyl-morpholinium chloride (DMTMM) as cross-linking agent for the development of carboxymethyl cellulose (CMC) films for food packaging is reported. Influence of different wt % of DMTMM and glycerol on the physical-mechanical properties of CMC films was investigated. The presence of DMTMM effectively improved moisture uptake, moisture content, water vapour permeability, water solubility of the films, oil resistance together with good biodegradability. Best compromise between high water resistance, vapour permeability and mechanical properties was accomplished with 5 wt % DMTMM and 50 wt % glycerol giving tensile strength and elongation at break of 52.25 ± 4.33 and 37.32 ± 2.04 respectively. DSC, TGA and SEM analysis further confirmed CMC cross-linking by DMTMM. All films prepared showed low opacity and high transparencies. Therefore, data reported show that DMTMM can efficiently cross-link CMC to produce films for food packaging.