Acquisition of alkali-soluble fluoride by enamel through treatment with NaF-containing toothpastes in vitro.

The first aim of the present study was to examine if alkali-soluble fluoride (calcium fluoride-like material and adsorbed fluoride) forms when a NaF-containing toothpaste is applied on human enamel surface in vitro. The centrifuged supernatants of toothpastes dissolved in distilled water were used and four different commercial NaF-containing toothpastes were tested. The second aim was to investigate if pyrophosphate would interfere with the deposition of alkali soluble fluoride. The formation of alkali-soluble fluoride was determined by chemical analysis and visualized by scanning electron microscopy (SEM). It was ascertained that all tested toothpastes contained free fluoride according to the manufacturers' specifications. It was shown that they promoted deposition of alkali soluble fluoride on the enamel surface. The amount of deposited material increased with the time of exposure. The clinical effect of a NaF-containing toothpaste may thus well depend on an initial formation of alkali-soluble fluoride. Fluoride from this reservoir may adsorb onto the enamel crystals and inhibit further demineralization or increase the rate of remineralization during cariogenic challenges. It was also demonstrated that pyrophosphate did not interfere with the deposition of alkali soluble fluoride.     

Histological evaluation of the effect of transseptal fibre resection on the rate of physiological migration of rat molar teeth.

Twenty-seven female Sprague-Dawley rats were given lead acetate as a vital stain, and rates of alveolar bone formation, representative of drift, were measured histologically. Teeth around which the transseptal fibre system had been destroyed drifted less quickly on both functioning (p less than 0.01) and non-functioning (p less than 0.001) sides than those with intact transseptal fibres. Both horizontal and vertical components of physiological drift were equally affected by destruction of the transseptal fibre system. It was felt that the transseptal fibres probably exerted their primary effect on the tooth, with bone remodelling around the drifting tooth being affected secondarily.     

Factors influencing mercury evaporation rate from dental amalgam fillings.

Factors influencing mercury evaporation from dental amalgam fillings were studied in 11 volunteers. Air was drawn from the oral cavity for 1 min and continuously analyzed with a mercury detector. In six volunteers the median unstimulated evaporation rate was 0.1 ng Hg/s, range 0.09-1.3 ng Hg/s. After chewing gum for 5 min the highest evaporation rate was 2.7 ng Hg/s. Chewing paraffin wax gave only a small increase in evaporation rate. Changes in airflow rates between 1.5 and 2.5 1/min during the 1 min sampling did not change the amount of mercury drawn from the oral cavity. Sampling with different mouthpieces and closed mouth was compared to open mouth sampling with a thin plastic tube. It was found that the latter method could result in lower values for some volunteers due to simultaneous mouth breathing. After placing individual plastic teeth covers in the mouth, the intraoral evaporation of mercury decreased immediately by 89-100% of previous levels. This technique could be used to detect mercury evaporation from separate amalgam fillings or to reduce the intraoral mercury vapor concentration. Rinsing the mouth with heated water for 1 min increased the mean evaporation rate by a factor of 1.7 when the water temperature increased from 35 degrees C to 45 degrees C.     

Documenting medication use in adult dental patients: 1987-1991.

The authors surveyed 5,002 dental outpatients to determine the prevalence and patterns of drug use. They found that drug use increased significantly with age and that a significant number of patients took medications that had potential for adverse dental effects. Thus, dentists should be aware of patient medications and the effects those drugs have on dental treatment.     

Visual and profilometric wear measurements.

Wear of composites can be estimated by the degree of marginal discrepancy between the prepared cavity wall and the occlusal margins of composites. Such evaluations are done on casts by comparing and rating the marginal discrepancy with those on standard casts. We analyzed the reliability of this technique on metal and stone specimens. These specimens contained grooves of different width and depth. For the visual comparison we used stone casts of machined standards of known groove depth. We measured the depths of the metal specimens with a profilometer and made stone casts of these original specimens. Using the stone casts of the standards, five dentists estimated the unknown groove depths on the remaining stone casts. These estimates were done under standardized conditions and repeated by each dentist on five different occasions. The results showed that visual depth evaluations of die stone specimens underestimated the depths when compared with the values measured with a profilometer on the original metal models. One investigator gave significantly different (p less than 0.05) groove depth estimates at different occasions.     

Prostaglandin E2 and interleukin-1 levels in smokeless tobacco-induced oral mucosal lesions

Inflammatory mediators released as a result of smokeless tobacco (ST)-induced irritation may play a role in the development of oral mucosal lesions at habitual tobacco placement sites in ST users. The present study examined levels of interleukin-1 (IL-1) and prostaglandin E2 (PGE2) in ST-induced mucosal lesions and compared these to mediator levels in clinically normal mucosa. Soft tissue biopsies were obtained from white mucosal lesions at habitual placement sites and normal alveolar mucosal tissue at non-placement sites in 18 ST users. Fifteen non-tobacco using subjects also provided normal alveolar mucosal biopsies. IL-1 and PGE2 were recovered from the specimens, and mediator levels were determined by enzyme immunoassay. Prostaglandin E2 levels (pg/mg) were lower in both regions in the ST subjects, but values did not vary significantly between the regions with 2.77±0.72 and 2.86±0.99 at placement and non-placement sites, respectively, in ST users and 7.31±3.84 in non-tobacco users. Both IL-1α and IL-lβ (pg/mg) were significantly (p < 0.0I) elevated in ST lesions (IL-lã=25.56±4.00; IL-1β=7.76±1.68) compared to either non-placement sites in ST users (IL-lα=14.64±2.65; IL-lβ=1.63±0.72) or non-tobacco users (IL-lα=12.84±2.60; IL-lβ=2.04±0.75). In view of IL-l's role in keratinocyte proliferation and its inflammatory effects, this cytokine may contribute to mucosal and gingival alterations observed in ST users.     

The effectiveness of the Titan-S sonic scaler versus curettes in the removal of subgingival calculus. A human surgical evaluation

This study evaluated clinically the effectiveness of hand versus sonic subgingival scaling and root planing in the removal of calculus by visually examining the root surface at the time of periodontal flap surgery. Consideration was given to the method of instrumentation, probing depth, number of roots, and type of tooth surface. Eleven patients with moderate to advanced periodontal disease were evaluated. Four subjects were scaled and root planed with the Titan-S only, four with curettes only, and three with the Titan-S + curettes. At reevaluation 3 to 6 weeks after scaling and root planing, the decision to perform periodontal flap surgery was made based upon probing depth, bleeding upon probing, previous access to the root surface, furcation involvement, and the patient's level of oral hygiene. A full thickness mucoperiosteal flap was elevated to gain access to the root surface and measure the distance from the cementoenamel junction to the residual calculus. A total of 690 surfaces were evaluated surgically. The percentage of surfaces with residual calculus for each method of instrumentation was: Titan-S only (31.9%), curettes only (26.8%), and Titan-S + curettes (16.9%). Overall, 15.7% of the surfaces probing 0 to 3 mm, 29.3% of the surfaces probing 4 to 5 mm, and 44.4% of the surfaces probing 6 to 12 mm had residual calculus.(ABSTRACT TRUNCATED AT 250 WORDS)     

Immigrants and a public oral health care service for children in Denmark

The present study was conducted to compare level of dental caries, treatment pattern and contact patterns with the Child Oral Health Care System of children of immigrants. The study comprised 239 Turkish, 117 Pakistani and 91 other immigrants and a control group of 359 Danish children. Data were extracted from the dental records in the clinic where they were treated. All groups of immigrants showed more caries in the primary dentition and less caries in the permanent dentition than Danish children of comparable age. For preschool children a higher number of broken appointments were found for the immigrants as well as a higher number of appointments which were interrupted due to management problems. The consequences for planning preventive and restorative programs for children of immigrants are discussed.