Microbial contamination of samples of dental unit water systems in Saudi Arabia

The purpoe of this study was to investigate contamination of the dental unit water systems in a sample of dental clinics in Saudi Arabia. A total of 270 water samples [200mL/sample] was collected from the handpieces line, air-water spray and tap water sources of the dental clinics. Microorganisms were identified using established culturing techniques [Analytab Products Inc.] The prevalence of bacterial contamination was 84% in dental unit water lines of handpieces and 64% in air-water spray, while it was 10% in tap water samples. Bacillus and Pseuodmonas were found to be the predominant [52%] pathogenic microorganisms. The results indicated that dental unit water systems tested were contaminated. Therefore, more effort should be directed to reduce [if not totally eliminate] the number of pathogens in the dental unit water systems

Transverse strength of various resin joints repaired with visible light cured reline material

Specimens of three different denture base resins were repaired with visible light cured [VLC] reline material and with the traditional sprinkle on autopolymerizing PMMA repair resin. Flexural properties were measured before and after repair and compared. These tests revealed that fiber. reinforced polymethylmethacrylate, [PMMA] denture base joints repaired with autopolymerizing acrylic resin can produce superior bonding properties. Transverse strength of joints made and repaired with the VLC acrylic resin system gave favorable pre-repair strength and lower post-repair strength. Significant differences were found between the flexural properties of the denture base resins used before and after repair. Plain and fiber reinforced PMMA acrylic resin joints repaired with the VLC reline material, showed a reduction of transverse strength ranging from 48.2%-56.4% of the original values. However, only 26.1% loss of strength was found for VLC denture base resin joints repaired with VLC reline material. This difference in strength reduction could be attributed to the poor adhesive bonding between the VLC reline material and the PMMA resin base