MATERIALS AND METHODS: Single- (Streptococcus mutans or Lactobacillus acidophilus), dual- (Streptococcus mutans/Lactobacillus Acidophilus), and multi-species (Streptococcus mutans, Actinomyces naeslundii, and Streptococcus sanguis) biofilms were grown on acid-etched dentine discs. Biofilms were incubated (120 min/37 °C) and allowed to grow for 3 days anaerobically. Discs (no treatment) served as control (group 1). Groups II, III, IV, and V were then treated with 2% chlorhexidine, and 2%, 5%, and 10% QAS (20 s). Discs were returned to well plates with 300 μL of bacterial suspension and placed in anaerobic incubator at 37 °C and biofilms redeveloped for 4 days. Confocal microscopy, Raman, CFU, and MTT assay were performed.
RESULTS: Raman peaks show shifts at 1450 cm-1, 1453 cm-1, 1457 cm-1, 1460 cm-1, and 1462 cm-1 for control, 2% CHX, 2%, 5%, and 10% QAS groups in multi-species biofilms. There was reduction of 484 cm-1 band in 10% QAS group. CLSM revealed densely clustered green colonies in control group and red confluent QAS-treated biofilms with significantly lower log CFU for single/dual species. Metabolic activities of Streptococcus mutans and Lactobacillus acidophilus decreased with increasing QAS exposure time.
CONCLUSION: Quaternary ammonium silanes possess antimicrobial activities and inhibit growth of cariogenic biofilms.
CLINICAL SIGNIFICANCE: Available data demonstrated use of QAS as potential antibacterial cavity disinfectant in adhesive dentistry. Experimental QAS can effectively eliminate caries-forming bacteria, when used inside a prepared cavity, and can definitely overcome problems associated with present available cavity disinfectants.
METHODS: Randomized controlled trials and cohort studies with a minimum 2-year follow-up assessing survival and complication rates of resin composite laminate veneers on permanent dentition from 1998 to May 2022. Literature searches were conducted in MEDLINE (PubMed), Scopus, and the Cochrane Central Register of Controlled Trials electronic databases. References cited in the related reviews and included full-text articles were also hand-searched to further identify potentially relevant studies.
RESULTS: A total of 827 articles were identified. Twenty-two studies were considered for full-text review after the title and abstract screening stage. After exclusion, 7 studies (3 randomized controlled trials and 4 cohort studies) were included in the systematic review. Three published scales were adopted for the quality and risk of bias assessment. At the survival rate threshold, the overall heterogeneity (I2) for randomized controlled trials was 50.5% (P = .108). The overall pooled survival rate of the randomized controlled trials was 88% (95% CI: 81%-94%), with the mean follow-up time ranging from 24 to 97 months. Surface roughness, color mismatch, and marginal discoloration were the most reported complications.
CONCLUSION: Resin composite laminate veneers demonstrated moderately high survival rates for the entire sample and the direct laminate veneer group demonstrated higher survival rates than the indirect approach. Most of the complications were regarded as clinically acceptable with or without reintervention.