Comparison of predominant cultivable microflora on acrylic denture base resin cured by two different techniques

Abstract

Objectives: To characterize the prevalence of normal microorganisms on complete upper dentures on successive weeks after insertion reaching a stable condition. Also, to find out the effect of the microwave curing system on the periodic microbiological growth on complete upper dentures and compare them with the results obtained from the water-bath curing method.
 Materials and Methods: Ten healthy fully edentulous patients were selected. A comparative micro flora on acrylic resin samples cured by two ways: the water-bath curing method and microwave curing energy. The samples fixed in the fitting surface of complete upper denture. The micro flora were studied during four experimental periods starting from zero time, the time just before the insertion of new complete dentures till the 6th week of denture insertion. The data were analyzed using SPSS software with T-test, and the differences were considered statistically significant at P<0.05.
 Results: Various microorganism species isolated from both samples, include streptococci, staphylococci, Gram-positive rods, Gram-negative rods and cocci.
 The microwave samples appeared to support significantly more aerobic Gram-positive rods and anaerobic Gram-negative rods, but less aerobic and anaerobic streptococci, Gram-negative cocci, and aerobic staphylococci. No candida growth could be identified before and after denture insertion. In spite of oscillate population of the bacteria, it has been noted it tends to stabilize on two subjects at the 10th week.
 Conclusions: It was difficult to decide which one of the either methods of curing acrylic resin is better in harboring fewer microorganisms. The number of both aerobic and anaerobic microorganisms significantly increased as the period of wearing denture is prolonged. Early plaque contains different kinds of bacteria; the majority was Gram-positive rods. No candida growth was detected.