Compositional analysis of human acquired enamel pellicle by mass spectrometry

Relatively little is known about the formation of the acquired enamel pellicle other than that it involves the selective adsorption of specific proteins from oral fluids. Previous studies on the identification of pellicle components have relied largely on immunological or enzymatic detection and have been hampered by the fact that only minute quantities of pellicle can be removed from tooth surfaces. The present work describes an improved method of harvesting pellicle that combines mechanical and chemical removal; this approach was used to investigate systematically the desorption of in vitro pellicle components with different solutions. Eleven major in vitro pellicle proteins were identified by using a combination of electrophoretic separation and matrix-assisted laser desorption/ionization-reflectron time-of-flight mass spectrometry. A similar analysis of in vivo-formed pellicle revealed the presence of intact statherin, lysozyme, albumin and amylase. Further analysis of in vivo pellicle by liquid chromatography-electrospray ionization mass spectrometry suggested the presence of numerous low molecular-weight fragments of precursor proteins. The protein composition of in vitro whole-salivary pellicle adsorbed to hydroxyapatite and that of in vivo enamel pellicle differed for proline, the result of a reduction in the content of acidic proline-rich proteins in the in vivo samples. Unique features of the oral environment such as enzymatic activities or mineral surface properties may account for these differences between in vivo and in vitro pellicle formation.     

Influence of cigarette filters on the risk of developing oral leukoplakia in a Kenyan population

OBJECTIVE: To determine the influence of cigarette filters and the effect of smoking Kiraiku (home processed, hand rolled tobacco) on the risk of developing oral leukoplakia among cigarette smokers. DESIGN: Case control using population-based study groups in a Kenyan rural community. MATERIALS AND METHODS: 85 cases and 141 controls identified in a cross-section house-to-house screening of subjects aged 15 years and over and matched for sex, age (+/- 3 years) and cluster origin were compared for their use of filter and non-filter cigarettes as well as their history of smoking Kiraiku. RESULTS: The relative risk (RR) of oral leukoplakia was 9.1 (95% confidence intervals (CI) = 4.1-20.2) in smokers of filter cigarettes and 9.8 (95% CI = 2.3-47.0) in smokers of non-filter cigarettes. The RR in the latter compared to the former was 1.1 and was not statistically significant. Regarding the influence of smoking Kiraiku, the RR of this lesion was 29.3 in smokers of both Kiraiku and filter cigarettes and 17.3 in smokers of both Kiraiku and non-filter cigarettes. CONCLUSIONS: There was no statistically significant difference between the influence of filter and non-filter cigarettes on the risk of developing oral leukoplakia. The effect of Kiraiku on the risk of this lesion was stronger in filter than in non-filter cigarettes. However, the confounding effect of tobacco dose response parameters could not be ruled out.     

At-home bleaching system: effect on gingival tissue.

This study evaluated the effects of an at-home vital bleaching system on gingival responses over a 6-week period. Objective measures were utilized to measure and monitor gingival inflammation over this period of time. Vital bleaching was performed as follows: (1) bleaching gel in a prefabricated mouthguard and (2) an ad-mix technique--bleaching gel and toothpaste in a 1:1 ratio. In addition a control group used a placebo in a prefabricated mouthguard. The at-home vital bleaching system produced no adverse gingival tissue responses. Furthermore, the at-home vital bleaching system helped produce a therapeutic effect on inflamed gingival tissues over the course of the study.     

Integrated currents between amalgams and a gold alloy in saline solutions and natural saliva with different chloride content.

The effect of different sodium chloride concentrations on the integrated currents (charge transfers) between dental amalgams and a gold alloy was studied in a bimetallic cell containing saliva or saline solutions. The integrated currents were only to a minor degree affected by increasing chloride concentrations for the high copper amalgams both in saliva and saline solutions. The integrated currents in the experiments involving conventional amalgam were several times higher than those for high copper amalgams. In saline solutions a charge transfer maximum was found at 0.2 M chloride. In saliva an increase of the charge transfer was found with increasing chloride content.     

Temperature differences at periodontal sites in health and disease.

The purpose of this study was to determine if a thermocouple probe was capable of detecting differences in temperatures between healthy and diseased periodontal sites. Twenty-two patients, 11 with radiographic evidence of periodontitis and 11 without, were probed twice with the temperature probe, and twice with a conventional probe by two examiners. Two definitions of health and disease were used. Definition one was that any site probing 5 mm or a site that bled upon probing was considered diseased. Sites 4 mm and with no bleeding on probing were considered healthy. Mean temperature differences were calculated from a baseline sublingual temperature. Each arch and tooth demonstrated different temperatures with temperatures decreasing from posterior to anterior. Differences from baseline between healthy and diseased sites were consistently higher for diseased sites. For example, maxillary second molars were 0.72 degrees C higher than baseline while the maxillary central incisors were 1.40 degrees C higher than baseline. Mean temperature differences between healthy and diseased sites were significant (P less than 0.005) for all sites. Definition two was developed since all sites 5 mm or greater and all sites which bled may not be diseased, the data were recalculated with disease including all sites greater than or equal to 5 mm with bleeding on probing and health including all sites less than or equal to 3 mm without bleeding. With this definition the mean temperature difference between healthy and diseased sites was even greater. Maxillary second molars were 0.96 degrees C higher, while maxillary central incisors were 1.76 degrees C higher.     

Parental attitudes toward behavior management techniques used in pediatric dentistry

Previous studies evaluating parents' attitudes toward behavior management techniques used in pediatric dentistry suggest that parental attitudes are generally negative. The purpose of this study was to reexamine this issue by comparing the effect of prior explanation on parental acceptance of eight behavior management techniques. Videotaped segments were made of children's dental appointments containing examples of eight behavior management techniques. One group of 40 parents viewed a videotape which provided no explanation for each technique before it was shown. Another group of 40 parents viewed a videotape which provided no explanation of the techniques. The parents then were asked to rate the acceptability of each technique using a visual analogue scale. Results indicated that the informed parents were significantly more accepting of behavior management techniques than the uninformed parents but both groups were generally positive about the techniques studied. Further, parents reporting greater stress were less accepting of the techniques studied.     

Evaluation of a dental unit with a built-in decontamination system

The efficacy of a dental unit equipped with a system that disinfects and sterilizes the water tubing by flushing with glutaraldehyde was evaluated by inserting Bacillus megaterium spores and Pseudomonas and Moraxella species into the water tubing. Up to 10(8) Pseudomonas and Moraxella organisms were killed during the disinfection cycle, but Bacillus megaterium spores were not. Up to 10(5) spores were eradicated by the sterilization cycle, although the system did not consistently kill 10(8) spores. The water tubing of the new unit was not naturally colonized by water bacteria during an 8-month period prior to the study. Evidence suggested that this was due to antimicrobial activity associated with the plastic tubing; therefore, microbial contamination of new dental units, irrespective of their design, would not be expected, until the inhibitory factor in the plastic tubing has leached out.     

An in vitro study of the effect endodontic access preparation and amalgam restoration have upon incisor crown retention

Endodontic access preparation leads to a significant reduction in crown retention. This study sought to determine whether this retention can be regained after access. Eighteen extracted human maxillary incisors had PFM crowns fabricated. Crowns were cemented, retention measured, recemented, access preparations cut, and retention once again measured. Then, crowns were recemented and accesses restored with dental amalgam and new retention measured. This format allowed each crown to be used as a control of itself. For crowns cemented with zinc phosphate cement and restored with amalgam, a 126% increase over original retention was measured. For crowns cemented with polycarboxylate cement and restored with amalgam, a 237% increase over original retention was measured. For crowns cemented with polycarboxylate cement and restored with amalgam, a 237% increase over original retention was measured. These results suggest that recementing crowns secondary to endodontic access and restoring the access with amalgam regains and even surpasses the original retention.     

Antimicrobial effect of chlorhexidine in a controlled release delivery system

Chlorhexidine is widely used as a mouth rinse in the prevention and treatment of periodontal diseases and dental caries. The purpose of the present study was to evaluate the in vitro antimicrobial effect of chlorhexidine in a controlled release delivery system. The controlled release dispenser comprised a polymeric inner core matrix containing the medicament with an outer vinyl membrane controlling the drug release. The effect on the following bacteria was studied: Actinobacillus actinomycetemcomitans, Actinomyces viscosus, Streptococcus mutans, Wolinella recta, Bacteroides gingivalis, Bacteroides intermedius, Eikenella corrodens, Pseudomonas aeruginosa, Enterobacter aerogenes, and Enterobacter cloacae. Chlorhexidine-containing vinyl patches with a diameter of 5.5 mm were placed on blood agar plates containing the various bacteria. The plates were incubated aerobically or anaerobically at 37 degrees C for 24 h or longer, when appropriate, and examined for inhibition of bacterial growth. Distinct zones of inhibition were seen surrounding all vinyl patches on all plates with all bacteria. Thus, the vinyl dispenser appeared to be an effective vehicle for releasing chlorhexidine to a localized area such as the surface of a tooth, a periodontal pocket, or a root canal.