The residual monomer content and mechanical properties of CAD\CAM resins used in the fabrication of complete dentures as compared to heat cured resins

Abstract

BackgroundThe utilization of computer-assisted designing and computer-assisted milling CAD\CAM resins in the fabrication of removable prostheses is a modern-day concept that offers many advantages over the use of the traditional polymethylmethacrylate (PMMA).AimThis study instigated some of the mechanical properties of CAD\CAM denture base resin including the amount of residual monomer.MethodsThis study was conducted at the Faculty of Dentistry, King Abdulaziz University from October 2016 to February 2017. A total of seventy rectangular specimens were fabricated (group A: 35 heat-cured PMMA and group B: 35 CAD/CAM pre-polymerized acrylic resin blocks). The flexural strength and surface hardness were tested while the residual monomer content at baseline, two-day and seven-day intervals was estimated using gas chromatography (GC). Means and standard deviations were determined for each group as well as independent-samples t-test and ANOVA with repeated measures for comparison between the groups and subgroups of varying time intervals.ResultsHeat cured PMMA (A), displayed higher flexural strength and low value flexural modulus compared to CAD/CAM acrylic resin denture base material (B). Student t-test indicated highly significant differences (p<0.001) of the flexural strength (t=37.911) and flexural modulus (t=88.559). The surface hardness of group (B) was significantly higher compared to group (A) as indicated by the t-test (t=20.430). Higher release of the monomer content was detected by GC in group (A) at different time intervals with a statistically significant difference (p<0.001) in residual monomer content.ConclusionCAD/CAM resin may be considered suitable for use in the construction of denture bases.

Synthesis and characterization of poly(N-isopropylmethacrylamide-co-N-isopropylacrylamide) copolymers

“…The liquid and gas chromatography (HPLC and GC) methods are used to analyze residual reactants in specific extracts. The aim of the polymer industry is to reduce the content of residual reactants in the process of the polymer production to the minimum [47][48][49][50][51][52].…”

Aplicabilidade dos sistemas CAD/CAM em Prótese Total: revisão de literatura

“…Ayman 22 2017 realizou uma pesquisa onde a força de flexão e a dureza da superfície foram testadas e o teor de monômero residual foi estimado usando cromatografia em fase gasosa e verificou que PMMA ativado por calor, mostrou maior força de flexão e módulo de flexão de baixo valor em comparação com a base da prótese de resina acrílica fabricada por CAD/CAM, nesta foi verificada maior dureza e valores menores de monômero residual.…”

Strains Induced in CAD/CAM Milled Mandibular Implant Retained Overdentures In vivo Strain Gauge Analysis

“…(48) The low strain resistance of conventionally processed PMMA dentures might thus be attributed to the presence of internal porosities and voids accompanied with the manufacturing procedure of the conventional heat cured PMMA as previously described and proved. (49) Also, the presence of residual monomer could explain the increased risk of denture base deformation. (49) The insignificant difference in microstrain recorded at chewing and non-chewing sides (Ch1and Ch5, Ch2 and Ch6) during gum chewing with CAD/CAM dentures may be related to the previously reported enhanced flexural strength, flexural modulus, and impact strength in comparison to the conventional heat-cured fabricated denture.…”