The aim of this study was to evaluate the level of residual monomer in acrylic denture base materials having different polymerization properties. The investigation included a conventional-type acrylic cured under heat and pressure, as well as a pour-type resin polymerized by an injection-moulding technique at room temperature and under pressure. It was found that the residual monomer content ranged from 0.22-0-54% in pour-type resin, and from 0.23-0-52% in routinely used resins when the specimens were analysed by high performance liquid chromatography. These findings revealed that there were no significant differences between the two types of acrylic in terms of their residual monomer content.

This study was performed to determine and compare the effect of heat and gamma-ray polymerization methods on the residual monomer and flexural strength of polyethylene fiber-reinforced denture-base acrylic resins. Four groups ( n = 10) of specimens of polyethylene fiber-reinforced denture-base material were prepared in the form of thin disks. The first group was subjected to heat-curing and the other three groups were polymerized with gamma irradiation at doses of 15, 25, and 35 kGy, respectively. Fourier-transform infrared (FTIR) spectrometer was used to monitor the corresponding polymerization processes. The analysis of residual monomer was carried out by high-performance liquid chromatography–photodiode array detector. A three-point bending test was used to evaluate the flexural strength of the samples. The one-way analysis of variance test was performed to determine the significant differences between the groups. The absence of the bands related to carbon–carbon double bond in the FTIR spectra of all test groups was an evidence of polymerization. The mean weight percentage of residual monomer was successively ranked from highest to lowest in; heat-cured, gamma-cured at 15–35 kGy. However, no significant difference ( p = 0.462) was found between gamma-cured samples at 25 and 35 kGy. Mechanical test results revealed that heat-cured samples had higher flexural strength than gamma-cured specimens ( p < 0.001). Within the limitations of this study, polymerization with gamma-rays at 15 kGy was proposed as a promising technique in terms of the residual monomer and flexural strength results.

In this study, the functional forces acting on maxillary complete dentures during mastication and swallowing were determined from three different locations by means of strain gauges. It was found that the functional forces caused by swallowing are quite marked in themselves and can cause deformation of the denture base resulting in undesirable force on the denture-bearing tissues.

No abstract

Bu çalışma, ısı ve gama ışını polimerizasyon yöntemlerinin, polietilen fiber ile güçlendirilmiş akrilik reçinelerde kalıntı monomer miktarı üzerindeki etkisini belirlemek ve karşılaştırmak için yapılmıştır. Polietilen fiber ile güçlendirilmiş akrilik reçine örnekleri disk formunda dört ayrı grup (n=10) olarak hazırlanmıştır. Bir grup ısı ile polimerize edilirken, diğer üç grubun polimerizasyonu gama ışınları ile üç farklı dozda gerçekleştirilmiştir. Kalıntı monomerin analizi, yüksek performanslı sıvı kromatografi-fotodiyot sıralı dedektörü (HPLC-PDA) ile gerçekleştirilmiştir. Gruplararasındaki farklılıkları tespit etmek için Kruskal-Wallis testi uygulanmıştır. Gama ışınları ile polimerize edilen akrilik örnek gruplarındaki artık monomer miktarlarının ısıyla polimerize edilmiş örneklerdeki artık monomer miktarına göre önemli ölçüde daha düşük olduğu gözlenmiştir (P < 0,001). Sonuç olarak 25 kGy'den daha düşük dozlarda gamma ışınları ile polimerizasyon, akrilik reçinelerdeki monomer içeriğini azaltmak için ümit verici bir teknik olarak önerilmiştir.