Antimicrobial susceptibility of 1042 strains of Streptococcus mutans and Streptococcus sobrinus: comparison from 1985 to 1989

A total of 1042 strains of Streptococcus mutans and Streptococcus sobrinus isolated between 1985 and 1989 were tested to study the evolution of their sensitivity to penicillin, amoxycillin, amoxycillin/clavulanic acid, cefuroxime, tetracycline, erythromycin, spiramycin, acetyl spiramycin, lincomycin and clindamycin. The strains were taken from stock cultures and isolated from human saliva and dental plaque. The minimal inhibitory concentration (MIC) was determined by an agar dilution method. Except for spiramycin and acetyl spiramycin, all the antibiotics inhibited 100% of the strains with concentrations less than or equal to 2 micrograms/ml. Microorganisms from both species underwent a slow progressive loss of sensitivity to all the antibiotics over a 5-year period of study, showing statistically significant results in most cases.     

Rectal ketamine and midazolam for premedication in pediatric dentistry

Rectally administered midazolam (0.30 mg/kg) and ketamine (5 mg/kg) were compared for preanesthetic medication in children undergoing dental extractions. Sixty patients between the ages 2 and 9 years were randomly allocated to three groups in this double-blind study. In one group of patients who received ketamine rectally, intravenous midazolam (0.05 mg/kg) also was administered immediately after induction of anesthesia. The results from this trial show that 30 minutes after rectal administration of the two drugs, good anxiolysis, sedation, and cooperation were obtained in most patients. Although midazolam appeared to be marginally more efficacious than ketamine in the majority of assessments made and seemed to have less adverse effects, no statistically significant differences could be shown. Ketamine showed a slight decrease and midazolam a slight increase in average blood pressures after premedication. These blood pressure differences were, however, considered to be of little clinical importance.     

Effects of different surgical regimes on nasal asymmetry and facial attractiveness in patients with clefts of the lip and palate

Surgery has often been blamed for the subsequent poor growth and deformity of the nasal complex in patients with cleft lip and palate. This study compares two groups of patients with unilateral clefts of the lip and palate for the effect that different surgical techniques have on nasal symmetry and facial attractiveness.     

Amoxycillin with clavulanic acid and tetracycline in periodontal therapy

The effects of tetracycline and amoxycillin with clavulanic acid on the clinical parameters and subgingival flora of eight patients with rapidly progressive periodontitis was assessed. Subjects received either tetracycline 250 mg four times daily or amoxycillin 250 mg with clavulanic acid 125 mg three times daily for a period of 2 weeks together with subgingival scaling and root planning. Both treatment regimens produced significant reductions in bleeding on probing and probing pocket depths which were still present 16 weeks after the antibiotic therapy. A significant reduction in the mean percentage of black-pigmented Bacteroides spp., Fusobacterium nucleatum and anaerobic corroding bacilli was also obtained. Both treatment regimens were equally effective in reducing the clinical parameter and altering the subgingival flora. The MIC values for Bacteroides gingivalis (Porphyromonas gingivalis). Bacteroides intermedius (Prevotella intermedia) and F. nucleatum to amoxycillin with clavulanic acid remained constant throughout the period of investigation. The MIC values of these organisms to tetracycline increased.     

Dental caries and fluoride exposure in Western Australia

Most water supplies in Western Australia (WA) have been fluoridated since about 1968, but one region has persistently resisted. Supplement use has been encouraged there, and fluoride toothpaste is widely used. Caries prevalence and caries experience in children in Perth (F- 0.8 mg/L) have declined steadily since fluoridation, but in the Bunbury region (F- less than 0.2 mg/L), caries measures remain higher than in Perth. The purpose of this study was to correlate the magnitude and timing of fluoride exposure with caries experience. Altogether, 592 randomly selected children born in 1978 (mean age, 11.8 years) in Perth and the Bunbury region provided residence and fluoride exposure information for the periods from birth to four and from four to 12 years of age. Caries experience was recorded clinically in accordance with DMFT and WHO criteria. Sixty-one percent had been continuous residents of fluoridated areas from birth to four years, and 51% between the ages of four and 12 years. Fluoride supplement use was low. By the age of 1.5 years, 42% had used toothpaste. The prevalence of caries was 0.38 in Perth and 0.61 in the Bunbury region, and mean DMFT scores were 0.89 (SD, 1.39) and 1.57 (SD, 1.60), respectively. Bivariate analysis revealed all fluoride exposure to be associated with reduced caries experience, but there were large correlations between some variables. When unconditional logistic regression analysis was used, the most important (p less than 0.05) odds ratios associated with no caries experience were for residence in a fluoridated area from four to 12 years of age and early use of toothpaste.(ABSTRACT TRUNCATED AT 250 WORDS)     

Periodontal tissue reactions to orthodontic extrusion

Orthodontic tooth extrusion is used at crown lengthening procedures or in conjunction with periodontal therapy aimed at eliminating or reducing angular bone defects. A technique for orthodontic extrusion combined with resection of the supracrestal attachment fibers (fiberotomy) was recently proposed as an adjunct to certain restorative procedures. The aim of the present investigation was to analyze reactions of the periodontal tissues to orthodontic extrusion when combined with fiberotomy. In 5 beagle dogs, the mesial roots of the 2nd, 3rd and 4th hemisected mandibular premolar were used as target roots while the distal roots served as reference units. After a baseline examination, an orthodontic extrusion device (stent) was installed and reactivated at 2-week intervals during an 8-week period of active tooth movement. Immediately following the installation of the stent and once every 2nd week, the target roots were exposed to fiberotomy. After the active period, the teeth were retained in their new position for a period of 8 weeks. Clinical, radiographical and histological measurements were performed. The results from the investigation demonstrated that orthodontic extrusion combined with supracrestal fiberotomy resulted in a coronal displacement of the tooth and was associated with pronounced recession of the gingival margin and extensive loss of connective tissue attachment. The degree of gingival recession and the amount of loss of connective tissue attachment were, however, less extensive than the amount of tooth extrusion. Thus, repeated fiberotomy obviously failed to entirely prevent coronal migration of the attachment apparatus. It was also observed that undesired attachment loss had occurred at the reference roots.     

A simplified approach to the complete porcelain margin.

The technique described produces a metal-ceramic crown exhibiting excellent esthetic qualities and marginal accuracy superior to that achieved on the cast metal margin. A platinum foil apron or refractory dies are not necessary. A precise shoulder preparation, preferably with two master dies, is required. A chamfer with a bevel, a shoulder with a bevel, or chamfer preparations are not suited to this technique. Quantitative evaluation using a measuring microscope showed that a marginal gap on a crown fabricated on an International Bureau of Standards crown die measured 6 microns at the porcelain shoulder and from 17 to 34 microns on a gold margin of the same crown. On a prepared-tooth, rubber-base compression densite die, the marginal gap on the porcelain shoulder was 10 microns.     

Preclinical laboratory course in dental behavioral science: changing human behavior.

Dental health professionals are frequently frustrated when they present preventive or therapeutic regimens to patients. This paper describes an approach to the teaching of behavioral science designed to familiarize the dental student with applying behavioral change techniques to dental problems. Ninety-nine second-year dental students participated in the two-credit course. Students were taught in six groups, each led by a clinician-behavioral scientist team. The behavioral science materials were presented in five slide-tape programs developed by the authors. The key to the course was a behavior change project in which each student identified a problem, designed an intervention strategy, and attempted to manage the problem using the behavioral techniques presented.     

Electron microscopic observations of the saliva-dependent aggregation of oral streptococci.

Cells of Streptococcus sanguis strain H7PR3 or Streptococcus mitis strain 26 aggregated in the presence of clarified whole saliva. Electron micrographs revealed the presence of two types of extracellular structures which were not detected in sections of control cells that were incubated without saliva, or in non-aggregating preparations in which cells were mixed with saliva plus ethylenediaminetetraacetate (EDTA). The sanguis-aggregating factor consisted of a round, globular component as well as an asymmetrical, fibrillar unit. The mitis factor appeared only as a globular structure. The dimensions and shapes of the aggregating factors were consistent with their known high molecular weights and, also, with the appearance of some of the intercellular matrix constituents of whole plaque.     

Performance of conventional and new methods for the detection of occlusal caries in deciduous teeth

The aim of this study was to compare, in vitro, the performance of different conventional diagnostic techniques with the laser-based device, DIAGNOdent, for diagnosis of occlusal caries in deciduous teeth. 95 deciduous teeth with macroscopically intact occlusal surfaces were selected. All teeth were assessed by the following techniques: visual inspection (VI), visual inspection with magnification (VIM), visual inspection combined with light pressure probing (VIP), bitewing radiography (BW) and the DIAGNOdent (DD). Caries extension was assessed by histology. DIAGNOdent showed, in comparison with the conventional clinical methods, a significantly improved ability (p < 0.05) to detect dentinal lesions (D(3) or D(4)) in deciduous teeth and an overall performance similar to that obtained in previous studies on permanent teeth. There was no statistically significant difference between VIM and DD in detecting caries confined to enamel (D(2)). DD performed better at D(2) level than the other methods. The intraexaminer kappa scores for DIAGNOdent were 0.76-0.86 (D(2)) and 0.77-0.85 (D(3)), respectively. It was concluded that DIAGNOdent could be used as an additional tool in the detection of occlusal caries in deciduous teeth and its good reproducibility should enable the laser device to monitor the caries process over time.