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Biomedical subjects

D H Leverett

Publications and source records attributed to D H Leverett.

At least 19 recordsLinked to original sources
PubMed1991

Associations of microbiological factors and plaque index with caries prevalence and water fluoridation status.

Plaque indices, numbers of mutans streptococci, lactobacilli and total viable flora in plaque and saliva were assessed as part of a large-scale cross-sectional study designed to determine the factors that are associated with high caries activity in children. Subjects, 12 to 15 years old, residing in areas where the water supplies were either fluoridated (n = 140) or fluoride-deficient (n = 173) were studied. Mutans streptococci and lactobacilli numbers in saliva were positively correlated with plaque index. Plaque indices were significantly higher in the high-caries group than in the zero-caries group of the fluoride-deficient community. In the fluoridated community, there was no difference in the plaque index between the zero- or high-caries groups. In each community, pooled dental plaque and saliva harbored fewer mutans streptococci and lactobacilli in the zero-caries than the high-caries group. Greater numbers of mutans streptococci were found in the dental plaque and saliva of the zero-caries subjects in the fluoridated community than in the fluoride-deficient community, suggesting that a greater caries challenge can coexist with zero-caries status in the fluoridated community.

Adolescent↗
PubMed1990

Correlations between numbers of microflora in plaque and saliva.

An epidemiologic investigation to reliably identify caries-susceptible subjects by microbiological and chemical assessment of plaque and saliva is currently in progress. As part of that study, the numerical relationships of mutans streptococci, lactobacilli and total viable microflora in plaque and saliva among 12- to 15-year-old children in a fluoridated community were determined. Paraffin-stimulated whole saliva and pooled dental plaque were collected. Each sample was suspended in reduced transport fluid, chilled on ice, and assayed. The bivariate normal distribution was found to be a suitable model for the distribution of the pairs [numbers of bacteria in plaque (log10), numbers of bacteria in saliva (log10)]. Statistically significant positive correlations were found between numbers of mutans streptococci in plaque and saliva, and between lactobacilli in plaque and saliva.

Adolescent↗
PubMed1989

Effectiveness of mouthrinsing with fluoride solutions in preventing coronal and root caries.

Fluoride mouthrinses have been used extensively for the past 15 years to prevent dental caries in children. Their use has been especially widespread in organized school-based programs in the US. Nearly three dozen clinical studies of fluoride mouthrinses, both with and without placebo controls, have been reported in the literature since the early 1960s. The overwhelming majority of those studies report statistically significant caries inhibition from the use of the products. Most of the studies were published prior to the knowledge of a decline in caries prevalence during the past 30 years. Consequently, the results of those studies lacking a placebo control group have been challenged. Even randomized clinical trials with appropriate control groups appear to be reporting declining differences between test and control groups. Using a model based on annual caries increments from published studies, the conclusion is reached that future use of fluoride mouthrinses is unlikely to result in annual savings in DMF increment greater than 0.4 surfaces, regardless of age of rinsers.

Clinical Trials as Topic↗
PubMed1988

Assessing diagnostic reliability and estimating incidence rates associated with a strictly progressive disease: dental caries.

This paper presents a general approach for simultaneously assessing, from serial data, diagnostic consistency, interrater reliability and incidence of a strictly progressive disease. Observed data are viewed as incomplete: diagnostic errors are not distinguished from true diagnoses. We introduce a broad class of models to separate rater errors from underlying patterns of disease incidence. The analysis can include covariates and risk factors. We provide variance expressions for parameter estimates. Categorical data for estimating the incidence of dental caries serve as an example.

Dental Caries↗
PubMed1987

Retention of sealants over carious and sound tooth surfaces.

Bacteriologic and clinical studies suggest that sealants can be used therapeutically on incipient caries of the enamel. The present study was designed to explore this approach further by determining whether there is a difference in retention rates on sound or carious tooth surfaces sealed for the first time as well as resealed surfaces. A total of 1766 teeth were sealed for subjects 12-14 yr of age of which 120 were judged to be carious. Mouths were divided sagittally on a random basis and an ultraviolet light activated resin with a filler or an autopolymerizing resin without a filler was placed on contralateral surfaces of all molar and premolar teeth. The effects of sealant type, caries status, arch and tooth type on retention over a 2-yr period were tested using Mantel-Haenszel statistics. At the end of 1 yr, 88% of the teeth sealed with the autopolymerizing resin were judged to be completely intact compared to 82% of the teeth filled with the ultraviolet light resin. At the end of the second year the retention rates were 84% and 75% respectively. The retention rates for carious and sound teeth at the end of both years were almost identical. Overall, premolars had a 15% more favorable retention rate than molars. There were minimal differences between arches although maxillary premolars had approximately a 5% higher retention rate than mandibular premolars. The reverse was true for molar teeth. Retention of sealants at the end of the second year (resealed after 1 yr) was 4% less than comparable teeth sealed initially.

Adolescent↗
PubMed1986

Dental caries and staining after twenty-eight months of rinsing with stannous fluoride or sodium fluoride.

The aim of this study was to compare the effects of daily mouthrinsing with aqueous solutions of 0.05% NaF or 0.1% SnF2 on dental caries and tooth staining. The study population consisted of 437 children, aged from 12 to 15 years at baseline, residing in a non-fluoridated community. By stratified random sampling, the subjects were divided into two groups, one group rinsing daily under supervision for 28 months with the NaF solution and the other with the SnF2 solution. The SnF2 group exhibited four to five times as much extrinsic stain as did the NaF group, although the stains were quite mild and not explicitly distinguishable between groups. There were no statistically significant differences between the two groups in terms of total DMFS. However, the increment of pit and fissure caries was 0.9 surfaces fewer for the SnF2 group (p = 0.04), while the increment of smooth surface caries was 0.6 surfaces fewer for the NaF group (p = 0.04). These data suggest that there may be a difference in mechanism of action between SnF2 and NaF rinses.

Adolescent↗
PubMed1986

Clinical radiographic evaluation of sealed carious and sound tooth surfaces.

The results of a 2-year radiographic assessment of 113 carious posterior teeth that were sealed with one of two sealants are presented. Little or no difference was found in radiographic ratings of caries by type of sealant. Sealant loss between annual recall visits had little or no detectable effect on radiographic ratings of caries during the study. Radiographs suggested that caries may regress in sealed teeth with early caries. The results support the safety of sealing incipient caries in pits and fissures to increase the potential uses of sealants.

Adolescent↗
PubMed1985

Weekly rinsing with a fluoride mouthrinse in an unfluoridated community: results after seven years.

In the fall of 1975, 1,915 children in grades K through eight began a school-based program of supervised weekly rinsing with 0.2 percent aqueous solution of sodium fluoride in an unfluoridated community in the Finger Lakes area of upstate New York. At baseline and annually thereafter, a random sample of children in grades K through 11 received clinical dental caries examinations. The prevalence of dental caries by grade at each of the follow-up dental examinations was compared to the grade-specific prevalence of dental caries at baseline. Overall, there was a decline of 57.8 percent in prevalence of caries in permanent teeth after seven years of rinsing. Among children in grades K through five, there was a decline of 35.4 percent in the prevalence of caries in primary teeth during the same time period. Tenth and eleventh grade children, after not rinsing for one and two years, respectively, continued to show the same trend toward lower caries prevalence as active rinsers. Caries prevalence among seventh and eighth graders after seven years of rinsing was not significantly different from caries prevalence among seventh and eighth grade lifetime residents of a nearby fluoridated community. A decline in the prevalence of caries in primary teeth among kindergartners prior to rinsing suggests that factors in addition to the mouthrinse program may have contributed to the decline in caries prevalence.

Adolescent↗
PubMed1977

A computerized system for the evaluation of community dental programs.

This paper reports on a relatively uncomplicated and inexpensive computerized system for prospective evaluation of clinical dental programs from the point of view of effectiveness and efficiency. Availability of this system does away with some high start-up costs. Three forms of input data, new case information, examination findings and operative procedure information, are regularly collected on data sheets and specially designed Port-a-punch IBM cards. Easily interpreted output tables are generated monthly on such variables as completed cases according to treatment series and clinician, number of various procedures performed by clinicians, etc. Productivity is measured, in part, by application of monetary constants to procedure data. This paper describes the computer programs used, the cost of setting up and operating the system (which is within the budgetary constraints of most small, publicly funded programs) and the benefits that can be derived from the use of such a system. The system provides prompt feedback of relevant administrative data, thus allowing for relatively quick response to problems. Use of the system reduces clerical needs to a minimum and the program can easily be implemented on any except the very smallest digital computer.

Community Dentistry↗
PubMed1977

Variations in utilization of a multi-state company dental plan.

A study was conducted of family records and claim forms of a company-sponsored dental plan to determine the effects of several demographic variables on utilization of the plan and on patterns of expenditure. The plan was non-contributory on the part of the employees. Individual utilization of the plan (at least once during the study year) closely approximated the average for the entire U.S. population. Salaried employees, and families, were more likely to use the plan than hourly-paid employees and families. High income families were more likely than lower income families to use the plan. Most of the independent variables (income, age, hourly versus salaried) correlated with utilization patterns in a predictable manner. A notable exception was when one looked from one division of the corporation to another, with 25 per cent of families in one division using the plan in the study year, compared to 90 per cent at another division. The reasons for these dramatic differences may be related, at least in part, to institutional factors rather than to patient behavior, and further study is indicated.

Adolescent↗