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Biomedical subjects

L V Powell

Publications and source records attributed to L V Powell.

25 records · Page 2Linked to original sources
PubMed1989

Effect of admixed indium on mercury vapor release from dental amalgam.

The purpose of this study was to evaluate the effect of admixed indium on the amount of mercury vapor released from dental amalgam. We made amalgam specimens according to ADA Specification Number 1. We added various amounts (0-14% by weight) of indium to the alloy powder. We also tested the commercial amalgams Dispersalloy, Valiant, and Indiloy. Specimens were held at 37 degrees C and 100% humidity. We used a Jerome Mercury Vapor Analyzer (model 411) to measure the mercury vapor released. We analyzed the data by means of ANOVA and Student-Newman-Keuls procedures. Admixed indium significantly decreased the amount of mercury vapor released from dental amalgams; the period of the greatest effect on mercury vapor released was during the setting phase of amalgam; and dental amalgams with greater than or equal to 8% admixed indium released the least amount of mercury vapor.

Air Pollutants↗
PubMedDate not supplied

Oral health and medical status in dentate low-income older persons.

Oral and medical conditions of 295 low-income dentate older persons (17% African-Americans, 14.5% Asians, 11.5% Hispanics, and 57% Caucasians) were studied. The mean age was 72 (SD +/- 6.8; range, 60-91). Oral examinations were performed, stimulated saliva was collected, and interviews were conducted regarding oral health attitudes, knowledge, and behaviors. Past history of restorative care, defined by filled coronal surfaces, differed by ethnicity, with Caucasian elders having most filled surfaces (p < 0.001). Ethnic minority elders had significantly poorer periodontal health (p < 0.001), with the worst conditions in Asians. Low salivary flow (< 0.01 mL/min) was found in 31% using medications known to cause hyposalivation. Frequent diseases were arthritis (46%), hypertension (39%), heart disease (25.2%), and diabetes (8.5%). Hypothyroidism was associated with low flow rate (F = 13.2, p < 0.0003). Seventy percent reported that they had never smoked. Smokers had deeper probing depths (chi 2 = 11.98, p < 0.05) and more gingival recession (F = 8.08, p < 0.001). Women on hormone replacement therapy (HRT) had less calculus (F = 11.33, p < 0.01) and fewer sites with probing depths > 5 mm (F = 8.99, p < 0.003). The present study found few associations between physical and oral health and ethnicity. The benefits of HRT for women's periodontal health and the effects of hypothyroidism on stimulated salivary flow are noteworthy.

Age Factors↗
PubMedDate not supplied

Caries prevention in a community-dwelling older population.

A clinical trial was conducted to compare the effect of different caries-preventive strategies on caries progression in lower-income, ethnically diverse persons 60 years of age and older. Two hundred and ninety-seven subjects were randomized into one of five experimental groups. Group 1 received usual care from a public health department or a private practitioner. Group 2 received an educational program of 2 h duration implemented twice a year. Group 3 received the educational program plus a 0.12% chlorhexidine rinse weekly. Group 4 received the education and chlorhexidine interventions and a fluoride varnish application twice a year. Group 5 received all the above interventions as well as scaling and root planing every 6 months throughout the 3-year study. A carious event was defined as the onset of a carious lesion, a filling, or an extraction on a surface which was sound at baseline. Two hundred and one subjects remained in the study for the 3-year period. Groups that received usual intraoral procedures (groups 3, 4, and 5) had a 27% reduction for coronal caries events (p = 0.09) and 23% for root caries events (p = 0.15), when compared to the groups that received no intraoral procedures (groups 1 and 2). Routine preventive treatments may have had only a small-to-moderate effect upon caries development.

Aged↗
PubMedDate not supplied

Effect of admixed indium on the clinical success of amalgam restorations.

The purpose of this study was to clinically evaluate two formulations of a dispersed-phase, high-copper dental amalgam alloy (Indisperse), which contained admixed indium. One alloy tested contained 5% indium, and the second alloy contained 10% indium. A similar alloy without indium, Dispersalloy, was also placed for comparison. Over the course of the five-year study, there were no differences clinically or statistically regarding texture and luster. The margins of the restorations containing indium incurred slightly less fracture than the non-indium-containing restorations; however, these differences were not clinically significant. It can be concluded that the admixture of 5-10% indium as well as the increased ratio of eutectic spheres to lathe-cut particles found in the indium alloys enhance the clinical performance of amalgam restorations.

Dental Amalgam↗
PubMedDate not supplied

Mercury vapor release during insertion and removal of dental amalgam.

During a clinical simulation of insertion and removal of dental amalgams, mercury vapor levels increased slightly, but never exceeded the TLV of 0.05 mg/m3. The addition of indium to dental alloy did not affect the amount of mercury vapor released under these conditions.

Air Pollution, Indoor↗
PubMedDate not supplied

Factors associated with clinical success of cervical abrasion/erosion restorations.

The purpose of this study was to evaluate the clinical performance of class 5 restorations according to USPHS criteria. Twenty-five patients and 116 abrasion/erosion lesions were restored with either a glass-ionomer cement restoration (Ketac-Fil), a composite resin restoration with a dentin bonding agent (Silux Plus, Scotchbond 2), or a composite resin restoration with a dentin bonding agent and a glass-ionomer liner (Silux Plus, Scotchbond 2, Vitrebond). At 3 years, 24 patients and 110 teeth were evaluated. All restorations were rated clinically acceptable for color match, cavosurface discoloration, surface texture, and caries development. Glass-ionomer cement restorations demonstrated a slightly rougher surface texture than the composite restorations (Friedman Two-way ANOVA, P=0.000). Significant differences were found with retention (Cochran Q test, P=0.012). Percentages retained were: glass ionomer, 97.3% (36/37); composite/dentin bonding agent, 75.7% (28/37); composite/dentin bonding agent/glass-ionomer liner, 100% (36/36). At 3 years class 5 restorations of glass-ionomer cement or composite with a dentin bonding and a glass-ionomer liner demonstrated significantly better retention than restorations of composite with a dentin bonding agent. Increased occlusal function, mobility, and mandibular arch were associated with a decrease in retention rate.

Aged↗