A study to investigate and compare the physicomechanical properties of experimental and commercial temporary crown and bridge materials

Publication date: Available online 31 December 2015
Source:Dental Materials
Author(s): Bana Abdulmohsen, Sandra Parker, Michael Braden, Mangala P. Patel
ObjectivesTo develop two experimental temporary crown and bridge materials with improved physicomechanical properties.MethodsCommercial materials: Trim (TR, monomethacrylate, Bosworth) and Quicktemp2 (QT, dimethacrylate, Schottlander). Experimental materials: isobutyl methacrylate/poly(ethyl methacrylate) (IBMA/PEM) and n-butyl methacrylate/PEM (nBMA/PEM), both monomethacrylates. For water absorption/desorption studies rectangular samples (40mm×10mm×1mm) of each material were prepared, immersed in deionized water (DW, control) and artificial saliva (AS), and weighed at regular time intervals. %solubility and diffusion coefficients (D) for uptake/loss processes were calculated and compared with theoretical predictions. Polymerization exotherm (cylindrical samples 10mm×18mm) and flexural moduli were measured (three point bending; rectangular samples 80mm×10mm×4mm, dry and after 9 days storage in DW). The data were compared statistically.ResultsQT and nBMA/PEM had lower %equilibrium uptakes/loss in DW (0.68%/0.884% and 0.64%/0.895% respectively). QT had the lowest water absorption/desorption D (P<0.05) compared to the three monomethacrylates, in DW and AS. %solubility for all systems showed no differences in DW (P>0.05), but a difference for QT in AS (P<0.05). QT reached its maximum temperature rapidly (∼2min; 3 monomethacrylates ∼7–13min). The commercial materials exhibited high peak temperatures (∼51°C, P<0.05; experimental materials ∼43°C). QT had a higher flexural modulus (∼4GPa; 3 monomethacrylates ∼0.7–1GPa) for dry and wet samples. The moduli for commercial materials reduced significantly after immersion in DW; there was no difference between the dry and wet experimental materials samples (P>0.05).SignificanceThe experimental materials merit further studies since they presented with lower setting exotherms, and contained no phthalate plasticizer, thus being less of a risk to patients.



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