A pilot study to evaluate the adhesion of oral microorganisms to temporary soft lining materials.

The aim of the study was to compare the adhesion of oral microorganisms to different types of soft liner and acrylic resin surfaces. Three different soft lining materials were applied to cavities formed on the fitting surfaces of prostheses in 17 patients. On days 1, 7 and 14, the specimens were taken out and immediately processed for bacteriological evaluation. The numbers of adhering microorganisms were calculated and the specimens were compared among each other and also with a control group (acrylic resin). Data were analyzed by two-way ANOVA and least squares differences at a significance level of P < 0.05. Among the four materials tested the total number of oral microorganisms adhering to Softliner material was the greatest after each of the time periods tested. Higher numbers of oral bacteria and Candida were shown to adhere to soft lining materials than to acrylic resin. Microbial coverage increased continuously with time and the differences between days 1 and 14 were statistically significant (P < 0.05). Temporary soft lining materials are not resistant to adhesion and possible surface damage caused by oral bacteria, and therefore their use should be limited to short-term periods.