Gayle B. McCombs

New discoveries and directions for medical, dental and dental hygiene research: low temperature atmospheric pressure plasma

The study of plasma integrates physics, chemistry, biology, and engineering, and has recently engaged medicine and dental hygiene in research efforts. The study of plasma holds promise for a myriad of applications ranging from lasers and electronics, hazardous waste management, decontamination, sterilization and disinfection of foods, soil, water, instruments, to medical uses in wound healing and treating certain types of tumours and cancers. Plasma represents a new state-of-the-art sterilization and disinfection treatment for certain oral and enviornmental pathogens, heat-sensitive materials, contaminated medical waste, hard and soft surfaces, and ventilation systems may assist health care facilities in the management of various health concerns. The role that Low Temperature Atmospheric Pressure Plasma (LTAPP) could play in the inactivation of pathogenic microorganisms might prove to be a new, faster, noncorrosive, more economical alternative, as well as support green healthcare.

A novel approach to controlling bacterial contamination on toothbrushes: chlorhexidine coating

PURPOSE This project was conducted to determine the effectiveness of chlorhexidine-coated toothbrush filaments in reducing quantities of bacteria. MATERIALS AND METHODS An Institutional Review Board (IRB)-approved, two-group, double-blind, randomized, post-test only study was conducted. Sixty-four individuals utilized control and experimental toothbrushes, for 30 days. At the end of the study toothbrushes were returned and transported to the laboratory for analysis. Microorganisms were detached from the filaments by sonification and vortexing then plated on Mitis Salivarius (MS) (selective) and trypticase soy agar (TSA) 5% Sheep Blood (non-selective) media. Inoculated plates were incubated aerobically for 24 h at 37 degrees C. After incubation, bacterial colony-forming units (CFU) were determined. Data were analysed using Wilcoxon and Kruskal-Wallis tests. RESULTS Fifty-nine toothbrushes were returned for analysis; experimental (n = 31) and control (n = 28). Data from TSA media revealed a mean CFU for the control group of 5.41 x 10(5) compared with 6.28 x 10(5) for the experimental group. Data from MS agar resulted in a mean CFU for the control group of 4.32 x 10(5) compared with 4.20 x 10(5) for the experimental group. CONCLUSION Results revealed no statistically significant difference in the quantity of bacteria surviving on toothbrush filaments between control and experimental groups, on both selective and non-selective media, after 30 days.

Clinical tests of an ultrasonic periodontal probe

A new ultrasonic periodontal probe has been developed that offers the potential for earlier detection of periodontal disease activity, non-invasive diagnosis, and greater reliability of measurement. A comparison study of the ultrasonic probe to both a manual probe, and a controlled-force probe was conducted to evaluate its clinical effectiveness. Twelve patients enrolled into this study. Two half-month examinations were conducted on each patient, scheduled one hour apart. A one-way analysis of variance was performed to compare the results for the three sets of probing depth measurements, followed by a repeated measures analysis to assess the reproducibility of the different probing techniques. These preliminary findings indicate that manual and ultrasonic probing measure different features of the pocket. Therefore, it is not obvious how the two depth measurements correspond to each other. However, both methods exhibited a similar tendency toward increasing pocket depths as Gingival Index scores increased....

Low temperature atmospheric pressure plasma applications in dentistry: Two independent studies

Low temperature atmospheric pressure plasma (LTAPP) may be used for various biomedical applications as this technology has the potential to inactivate and destroy microorganisms1,2. Purpose: The purpose of these two independent studies was to evaluate the efficacy of LTAPP on the inactivation of Geobacillus stearothermophilus, Bacillus cereus and Streptococcus mutans. The microorganisms of the study are of dental relevance. Methods: In Study 1, 981 samples were processed (762 experimental samples exposed to LTAPP, 219 control samples). Experimental samples of G. stearothermophilus and B. cereus (vegetative cells and spores) were exposed indirectly or directly to cold plasma at various time intervals for each microorganism state and type of exposure (indirect exposure time range: 1 minute-30 minutes; direct exposure time range: 30 seconds-30 minutes). In study 2, 90 samples were processed (72 experimental samples exposed to LTAPP, 18 control samples). Experimental samples of S. mutans were exposed directly to cold plasma for 60, 120, 180 or 300 seconds. In both studies: control samples were not exposed, colony forming units were counted, percentage kill/ inactivation factor were determined and data were analyzed at 0.05a significance. Analysis for study 1 included one-way ANOVA, Kruskal Wallis and Tukeys tests and study 2 used repeated measures ANOVA. Results: Study 1: Statistically significant reduction of G steraothermophilus vegetative cells and B. cereus vegetative cells and spores (indirect and direct exposure p-values O.025). There was no statistically significant reduction for G stearothermophilus spores (indirect p=3D0.7208, direct p=3D0.0835). Study 2: Statistically significant reduction of S. mutans at all time exposures: 60 (p=3D0.0272), 120, 180 and 300 seconds (p=3D0.0001). Conclusions: Results demonstrate that LTAPP effectively kills G stearothermophilus vegetative cells, B. cereus vegetative cells and spores and S. mutans. G stearothermophilus spores were not significantly inactivated.