Faculty Bibliography

The purpose of this study was to determine the antimicrobial activity of eight commercially available etchant materials and positive and negative controls as they came into contact with bacteria commonly found within the oral cavity. The following bacteria were used in this study: Streptococcus mutans, Streptococcus salivarius, and Actinobacillis actinomycetocomitants. The study was conducted in two parts: Part I--Etchants and controls placed within wells in agar plates; Part II--Enamel-dentin disks saturated with the etchants for 20 seconds and placed on the agar plates with the controls. Zones of microbial inhibition were measured in millimeters after 48 hours. The results of the study indicate that all of the etchants demonstrated antimicrobial activity against the bacteria tested.

The purpose of this in vitro study was to compare the apical seals achieved using retrograde amalgam fillings or the Nd:YAG laser. Freshly extracted teeth were randomly separated into groups that would have their apices treated either with a Nd:YAG laser or retrograde amalgam. After instrumentation and obturation, bacterial reservoirs were prepared in the coronal portion of canals. Teeth to receive retrofillings had their apices prepared and amalgams placed. Teeth to be lasered had no apical preparations. Teeth and culture media were then sterilized by irradiation. Streptococcus salivarius was deposited in the opened bacterial reservoirs. At intervals, culture media with an indicator in culture chambers was observed for color change. Specimens that demonstrated color change were cultured for S. salivarius. Under the conditions of this in vitro study, no statistically significant difference was found in bacterial leakage between the laser-treated group and the retrograde amalgam group

In this study, the effectiveness of Professional Lysol (PL) disinfectant in both its spray and solution forms was evaluated as a surface disinfectant for irreversible hydrocolloid (IH) impressions. Sixteen impressions of a typodont were made with IH, immersed in a microbial broth, and then rinsed in running tap water. The impressions were then treated as follows: four were immersed in PL for 2.5 minutes; four were sprayed by PL and stored for 10 minutes; four were immersed in 2% glutaraldehyde for 10 minutes; four were untreated. Pretest plates showed an average of 421 colonies per plate (c/p). The glutaraldehyde group showed 0.00 c/p. The PL spray group showed 1.75 c/p. The PL immersion group showed 19.00 c/p and showed evidence of surface deterioration in the IH. The untreated group showed 426.25 c/p

The purpose of this in vivo double-blind study was to determine and compare the antimicrobial effectiveness of four commercial over-the-counter mouthwashes and a water control. Two of the products tested contained alcohol (Listerine and Scope) and two products were alcohol-free (Rembrandt Mouth Refreshing Rincs and Clear Choice). The antimicrobial efficacy of the products was determined against aerobic, microaerophilic, and anaerobic bacteria in saliva. Thirty human subjects participated in the study. At each experimental session for a given subject, a pretest saliva sample was taken. This sample was divided and used to grow three bacteria cultures under the different incubation environments. After giving the pretest sample, the subject rinsed with one of the commercial mouthwashes or the water control for 30 seconds, then waited one hour at which time a posttest saliva sample was collected. Again, the sample was divided and used to culture the different type of bacteria. Following a 48-hour incubation period, the numbers of microbial colonies on each plate were counted and compared. The results indicated that all of the mouthwashes tested performed significantly better than the water control. Both of the non-alcohol-containing products showed efficacy in inhibiting aerobic, microaerophilic, and anaerobic bacteria. Rembrandt Mouth Refreshing Rinse and Listerine inhibited all three types of bacteria, and were not significantly different from each other in efficacy. The Rembrandt mouth wash inhibited all three types of bacteria more effectively than Clear Choice mouthwash, and inhibited two of the three types of bacteria more effectively than Scope mouthwash

This in vitro study compared the antimicrobial effect of several at-home bleaching agents and an oral antiseptic against anaerobic bacteria that are commonly found in the oral cavity. Zones of inhibition produced by Rembrandt Lighten Bleaching Gel, Opalescence, and Peroxyl were measured and compared. All the materials produced zones of inhibition with the five bacteria used in the study

Four hydrocolloid conditioning units were randomly tested for bacterial contamination. All were contaminated beyond the United States Army's acceptable limit of potability. The predominant bacteria were identified. A discussion of clinical significance and proposals for aseptic technique are presented

Bacillus subtilis 168ts-200B is a temperature-sensitive mutant of B. subtilis 168 which grows as rods at 30 C but as irregular spheres at 45 C. Growth at the nonpermissive temperature resulted in a deficiency of teichoic acid in the cell wall. A decrease in teichoic acid synthesis coupled with the rapid turnover of this polymer led to a progressive loss until less than 20% of the level found in wild-type rods remained in spheres. Extracts of cells grown at 45 C contained amounts of the enzymes involved in the biosynthesis and glucosylation of teichoic acids that were equal to or greater than those found in normal rods. Cell walls of the spheres were deficient also in the endogenous autolytic enzyme (N-acyl muramyl-l-alanine amidase). Genetic analysis of the mutant by PBS1-mediated transduction and deoxyribonucleic acid-mediated transformation demonstrated that the lesion responsible for these effects (tag-1) is tightly linked to the genes which regulate the glucosylation of teichoic acid in the mid-portion of the chromosome of B. subtilis.