Title: 0346 - Colonization of Commercial PMMA Using an In Situ Approach


António Delgado (Presenter)
Cooperativa de Ensino Superior Egas Moniz

Inês Caetano Santos, Cooperativa de Ensino Superior Egas Moniz
Joana Carvalho, Cooperativa de Ensino Superior Egas Moniz
Teresa Nascimento, Cooperativa de Ensino Superior Egas Moniz
Sérgio Félix, Cooperativa de Ensino Superior Egas Moniz
José Mendes, Cooperativa de Ensino Superior Egas Moniz


Objectives: To research the initial microbial adhesion in situ of a commercial acrylic resin used in prosthodontics, and compare it to the oral microbiome of participants.

Methods: Calibrated disks of a commercial acrylic resin – Probase Hot® (Ivoclar) were prepared and included on the surface of individual intra-oral splints fabricated for 50 participants. The splints were used for 4h, under clinical conditions, subject to microbiological colonization. Beforehand, each participant was swabbed to provide a control group for microbiological comparison. After the time elapsed, each splint was removed, the acrylic resin was processed and the growth of total anaerobes, total aerobes, Pseudomonas, oral Streptococci, Staphylococci, yeasts, and Streptococcus mutans was determined by plate counts and compared to the oral microbiome. Means and standard deviations were calculated and expressed in CFU/mm2. A non-parametric Wilcoxon test was employed to compare both experimental groups. Spearman’s correlation coefficient was calculated to investigate a correlation between the growth of anaerobes and aerobes in both sample groups. The significance level was set at 0.05 (95% CI), and statistical analysis was performed using Statistical Package for the Social Sciences (SPSS).

Results: With exception of yeasts and Pseudomonas, all microbial groups colonized the acrylic resin. No statistically significant differences were found between the tested microorganisms which colonized the oral microbiome and the acrylic resin’s surface, except regarding yeasts (p>0.05). A positive and moderate correlation between the growth of aerobe and anaerobe species in the acrylic resin was observed (p≈0.001).

Conclusions: Microbial adhesion to the acrylic resin was substantial, with multiple species adhering in the short time frame of this experiment, highlighting the potential of microorganism uptake of this material. Microbial species colonizing the acrylic resin were found to be quantitatively and qualitatively similar to the oral biofilms.

Student Presenter

Disclosure Statement:
The submitter must disclose the names of the organizations with which any author have a relationship, the nature of the relationship, and the clinical or research area involved. The following is submitted: NONE