Effect of Water Sorption on the Ultimate Transverse Strength of a Heat-cured Denture Base Resin Relined with Direct Denture Reline Materials.

Abstract

The effect of water sorption on the ultimate transverse strength of a heat-cured denture base resin relined with four different direct denture reline materials was investigated.The relined specimens were tested after 1 day and 1 month of water immersion. It was found that prolonged duration of water immersion and an increase in the thickness of the reline material significantly (p<0.01) decreased the ultimate transverse strength of specimens relined with powder-liquid type direct reline materials. Specimens relined with paste type reline material did not change the ultimate transverse strength after 1 month of water immersion significantly.

Effect of long-term water immersion or thermal shock on mechanical properties of high-impact acrylic denture base resins

“…The flexural strength at the proportional limit [12][13][14][15][16] and the elastic modulus of the specimens were tested. Each specimen was placed on a 50 mm-long support for three-point flexural testing.…”

“…Removable denture base resins typically exhibit considerable plastic deformation before fracture. The plastic deformation beyond its proportional limit permanently alters the dimensions of a removable denture, and it is not clinically acceptable; therefore, some studies evaluated the resistance of denture base resins to plastic deformation under a flexural load [12][13][14][15][16] . Despite, the flexural strength at the proportional limit of high-impact denture base resin has not been quantified.…”

Microwave assisted disinfection method in dentistry

“…From these experiments, a reduction in surface hardness of the artificial denture teeth was observed after microwave irradiation. It seems that the high temperature associated with the movements of the molecules probably caused an increase in the speed of diffusion of the water molecules into the polymer, facilitating the movement of the polymeric chains during performance of the hardness (Takahashi et al, 1998). Thus, it is feasible that the reduction in hardness after irradiation is related to water sorption rather than to microwave irradiation.…”

Akri̇li̇k Rezi̇nler, Yumuşak Astar Materyalleri̇ Ve Doku Düzenleyi̇ci̇leri̇n Çözünürlük Özelli̇kleri̇

“…Bazı araştır-macılar su moleküllerinin polimer matriks içerisine penetre olarak plastizer gibi görev yaptığını ve akrilik kaidelerin ve yumuşak astar materyallerinin mekanik özelliklerini olumsuz olarak etkilediği belirtmektedirler. [5][6][7] Tam tersine bazı araştırmacılar ise su gibi küçük plastizer moleküllerin ortamda bulunmasının enerjiyi dağıtan moleküler harekete yardımcı olduğunu bildirmektedirler. 8 Akrilik rezin suya batırıldığında 2 fenomen doğal olarak gerçekleşir; su emilimi ve residüel monomer salınımı.…”

“…Bundan dola-yı kaide polimerindeki moleküllerin miktarı zaman içerisinde değişir. [5][6][7]9 Çözünürlük ise polimerden çözünen maddelerin salınması olarak tanımlanır. 10 Rezinlerin ağız içinde temas ettikleri birçok sıvıda çözünmemesi istenir.…”