The occurrence of porosity in a heat-cured poly (methyl methacrylate) denture base resin

Background:Conventional heat cure poly methyl methacrylate (PMMA) is the most commonly used denture base resin despite having some short comings. Lengthy polymerization time being one of them and in order to overcome this fact microwave curing method was recommended. Unavailability of specially designed microwavable acrylic resin made it unpopular. Therefore, in this study, conventional heat cure PMMA was polymerized by microwave energy.Aim and Objectives:This study was designed to evaluate the surface porosities in PMMA cured by conventional water bath and microwave energy and compare it with microwavable acrylic resin cured by microwave energy.Materials and Methods:Wax samples were obtained by pouring molten wax into a metal mold of 25 mm × 12 mm × 3 mm dimensions. These samples were divided into three groups namely C, CM, and M. Group C denotes conventional heat cure PMMA cured by water bath method, CM denotes conventional heat cure PMMA cured by microwave energy, M denotes specially designed microwavable acrylic denture base resin cured by microwave energy. After polymerization, each sample was scanned in three pre-marked areas for surface porosities using the optical microscope. As per the literature available, this instrument is being used for the first time to measure the porosity in acrylic resin. It is a reliable method of measuring area of surface pores. Portion of the sample being scanned is displayed on the computer and with the help of software area of each pore was measured and data were analyzed.Results:Conventional heat cure PMMA samples cured by microwave energy showed maximum porosities than the samples cured by conventional water bath method and microwavable acrylic resin cured by microwave energy. Higher percentage of porosities was statistically significant, but well within the range to be clinically acceptable.Conclusion:Within the limitations of this in-vitro study, conventional heat cure PMMA can be cured by microwave energy without compromising on its property such as surface porosity.

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“…[12] stated that the generation of porosity in PMMA denture base is apparently a complex phenomenon and which is multi-factorial in origin.…”

Section: Discussionmentioning

confidence: 99%

Comparative evaluation of surface porosities in conventional heat polymerized acrylic resin cured by water bath and microwave energy with microwavable acrylic resin cured by microwave energy

2013

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“…The porosity of acrylic denture base resins has been mainly investigated by naked eye or microscopic analysis 31,32 and by a method that employs the volume of water absorbed by the material 8,23 . The porosity of temporary acrylic-based soft liners has been scored by microscopic analysis 15,16,21 , a limited method that evaluates the pores only superficially, even when specimens are sectioned 2 .…”

Section: Discussionmentioning

confidence: 99%

Porosity of temporary denture soft liners containing antifungal agents

et al. 2016

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“…Porosity has been attributed to a variety of factors such as air entrapped during mixing, monomer contraction during polymerization, monomer vaporization associated with the exothermic reaction, and the presence of residual monomer (Keller & Lautenschlager, 1985;Wolfaardt et al, 1986). According to Tager (Tager, 1978) porosity is a property of solids that relates to their structure and is expressed in the presence of voids (pores) between separate grains, layers, crystals, and other elements of a coarse structure of a solid.…”

Section: Porosity and Color Stabilitymentioning

confidence: 99%

“…Considering the processing methods for acrylic resins, some authors (Austin et al, 1982;May et al,1992) have stated that polymerization for short period of time promotes higher color instability. Porosity and its consequences have been studied to resin processed by microwave energy (Reitz et al, 1985;Wolfaardt et al, 1986;De Clerck, 1987;Al Doori et al, 1988;Truong & Thomasz, 1988;Levin et al, 1989;Shlosberg et al, 1989;Alkhatib et al, 1990;Bafile et al,1991;Sadamori et al, 1994;Ilbay et al,1994;) and some authors verified that it depends on the base thickness (Sanders et al, 1987) or the selection of the material, despite of the microwave processing. (Yannikakis et al, 2002).…”

Section: Porosity and Color Stabilitymentioning

confidence: 99%