Ultraconservative dentistry represents a great step forward for the dentist, the profession, and especially the patient. It involves the early detection and complete elimination of all accessible and non-accessible carious material from the tooth. Untreated caries can be extremely and rapidly destructive. The earliest interception of decay maintains total dental health and increases the likelihood of the restored teeth lasting a lifetime. (+info)
Microbial biofilm formation and contamination of dental-unit water systems in general dental practice.
Dental-unit water systems (DUWS) harbor bacterial biofilms, which may serve as a haven for pathogens. The aim of this study was to investigate the microbial load of water from DUWS in general dental practices and the biofouling of DUWS tubing. Water and tube samples were taken from 55 dental surgeries in southwestern England. Contamination was determined by viable counts on environmentally selective, clinically selective, and pathogen-selective media, and biofouling was determined by using microscopic and image analysis techniques. Microbial loading ranged from 500 to 10(5) CFU. ml(-1); in 95% of DUWS water samples, it exceeded European Union drinking water guidelines and in 83% it exceeded American Dental Association DUWS standards. Among visible bacteria, 68% were viable by BacLight staining, but only 5% of this "viable by BacLight" fraction produced colonies on agar plates. Legionella pneumophila, Mycobacterium spp., Candida spp., and Pseudomonas spp. were detected in one, five, two, and nine different surgeries, respectively. Presumptive oral streptococci and Fusobacterium spp. were detected in four and one surgeries, respectively, suggesting back siphonage and failure of antiretraction devices. Hepatitis B virus was never detected. Decontamination strategies (5 of 55 surgeries) significantly reduced biofilm coverage but significantly increased microbial numbers in the water phase (in both cases, P < 0.05). Microbial loads were not significantly different in DUWS fed with soft, hard, deionized, or distilled water or in different DUWS (main, tank, or bottle fed). Microbiologically, no DUWS can be considered "cleaner" than others. DUWS deliver water to patients with microbial levels exceeding those considered safe for drinking water. (+info)
Occupational exposures to blood in a dental teaching environment: results of a ten-year surveillance study.
Evaluation of occupational exposures can assist with practice modifications, redesign of equipment, and targeted educational efforts. The data presented in this report has been collected as part of a ten-year surveillance program of occupational exposures to blood or other potentially infectious materials in a large dental teaching institution. From 1987 to 1997, a total of 504 percutaneous/non-intact skin and mucous membrane exposures were documented. Of these, 494 (98 percent) were percutaneous, and 10 (2 percent) were mucosal, each involving a splash to the eye of the dental care worker (DCW). Among the 504 exposures, 414 (82.1 percent) occurred among dental students, 60 (11.9 percent) among staff, and 30 (6 percent) among faculty. One hundred ninety-one (37.9 percent) exposures were superficial (no bleeding), 260 (51.6 percent) were moderate (some bleeding), and 53 (10.5 percent) were deep (heavy bleeding). Regarding the circumstances of exposure, 279 (54.5 percent) of the injuries occurred post-operatively (after the use of the device), and most were related to instrument clean-up; 210 (41.0 percent) occurred intra-operatively (during the use of the device); and 23 (4.5 percent) occurred when a DCW collided with a sharp object in the dental operatory (eight cases involved more than one circumstance). The overall exposure rate for the college was 2.46+/-0.11 SD per 10,000 patient visits. The average rate for the student population was 4.02+/-0.20 SD per 100 person-years, with the highest rates being observed among junior year students. The observed rates of occupational exposures to blood and body fluids in this report are consistent with published reports from several other educational settings. Dental teaching institutions are faced with the unique challenge of protecting the student and patient populations against bloodborne infections. Educational efforts must go beyond mere teaching of universal precautions and should include the introduction of safer products and clinical procedures that can minimize the risks associated with the hands-on aspects of the students' learning process. (+info)
Displaced polishing discs: two case reports.
Routine dental treatment is not without its hazards. Two cases of trauma to the buccal soft tissues caused by displaced polishing discs are reported and suggestions made regarding the long-term use and maintenance of dental instruments. (+info)
Corneal rust removal by electric drill. Clinical trial by comparison with manual removal.
The dental burr rotated by an electric drill is the quickest, safest, and most precise form of treatment for corneal rust rings. It enables complete removal of the corneal rust at a single treatment and leaves a smooth crater that is no larger than the original rust ring. Pain relief is more rapid after electric drill removal; this is probably related to the complete removal of the rust. Epithelial and stromal healing are marginally faster than after manual removal and the patients' duration of attendance is less. The ideal drill is a slim straight instrument, which rotates dental burrs and is operated by a light finger pressure. A brake which stops drill rotation on lifting the finger is a useful safety feature. (+info)
Cervical shaping in curved root canals: comparison of the efficiency of two endodontic instruments.
The aim of this study was to determine the removal of dentin produced by number 25 (0.08) Flare files (Quantec Flare Series, Analytic Endodontics, Glendora, California, USA) and number 1 e 2 Gates-Glidden burs (Dentsply - Maillefer, Ballaigues, Switzerland), in the mesio-buccal and mesio-lingual root canals, respectively, of extracted human permanent inferior molars, by means of measuring the width of dentinal walls prior and after instrumentation. The obtained values were compared. Due to the multiple analyses of data, a nonparametric test was used, and the Kruskal-Wallis test was chosen. There was no significant difference between the instruments as to the removal of dentin in the 1st and 2nd millimeters. However, when comparing the performances of the instruments in the 3rd millimeter, Flare files promoted a greater removal than Gates-Glidden drills (p > 0.05). The analysis revealed no significant differences as to mesial wear, which demonstrates the similar behavior of both instruments. Gates-Glidden drills produced an expressive mesial detour in the 2nd and 3rd millimeters, which was detected trough a statistically significant difference in the wear of this region (p > 0.05). There was no statistically significant difference between mesial and lateral wear when Flare instruments were employed. (+info)
A pilot investigation of enamel reduction procedures.
OBJECTIVE: To test and describe the use of various combinations of mechanical and chemical techniques for enamel reduction to obtain a smooth surface. METHODS: Bovine teeth (2 surfaces on each of 32 teeth) were used. The teeth were mounted in blocks of dental plaster, which were then mounted in a vise. The mesiodistal enamel contact areas were reduced by various combinations of mechanical and chemical aids. The mesiodistal width of each tooth was measured with a digital caliper after initial reduction of the enamel surface and again after polishing. The teeth were subsequently prepared and mounted for scanning electron microscopy. RESULTS: All combinations yielded statistically significant enamel reduction (p < 0.05). The use of acid stripping in conjunction with mechanical procedures produced especially smooth enamel surfaces. CONCLUSIONS: Steps must be taken to ensure that a smooth enamel surface remains after enamel reduction and polishing. It is recommended that conventional enamel etchants be added to the polishing procedure. Enamel reduction can increase available space, but the quantity of enamel that can be removed without adverse consequences should be carefully evaluated. (+info)
Microbial diversity of biofilms in dental unit water systems.
We investigated the microbial diversity of biofilms found in dental unit water systems (DUWS) by three methods. The first was microscopic examination by scanning electron microscopy (SEM), acridine orange staining, and fluorescent in situ hybridization (FISH). Most bacteria present in the biofilm were viable. FISH detected the beta and gamma, but not the alpha, subclasses of Proteobacteria: In the second method, 55 cultivated biofilm isolates were identified with the Biolog system, fatty acid analysis, and 16S ribosomal DNA (rDNA) sequencing. Only 16S identified all 55 isolates, which represented 13 genera. The most common organisms, as shown by analyses of 16S rDNA, belonged to the genera Afipia (28%) and Sphingomonas (16%). The third method was a culture-independent direct amplification and sequencing of 165 subclones from community biofilm 16S rDNA. This method revealed 40 genera: the most common ones included Leptospira (20%), Sphingomonas (14%), Bacillus (7%), Escherichia (6%), Geobacter (5%), and Pseudomonas (5%). Some of these organisms may be opportunistic pathogens. Our results have demonstrated that a biofilm in a health care setting may harbor a vast diversity of organisms. The results also reflect the limitations of culture-based techniques to detect and identify bacteria. Although this is the greatest diversity reported in DUWS biofilms, other genera may have been missed. Using a technique based on jackknife subsampling, we projected that a 25-fold increase in the number of subclones sequenced would approximately double the number of genera observed, reflecting the richness and high diversity of microbial communities in these biofilms. (+info)