PubMed Health⌕ Search

Biomedical subjects

C M Hanes

Publications and source records attributed to C M Hanes.

At least 19 recordsLinked to original sources
PubMed1999

Estrogenicity of bisphenol A and bisphenol A dimethacrylate in vitro.

Although pit and fissure sealants have been utilized extensively in dentistry as a way of preventing occlusal caries, results described by Olea et al. (1996) raised concerns about the safety of sealants and other resin-based dental materials due to the reported presence of bisphenol A (BPA) and its dimethacrylate ester (BPA-DM). Although the release of these compounds from dental materials has not been substantiated by two subsequent studies, we believed it was important to confirm or refute the report that BPA and BPA-DM have estrogenic activity in vitro. We grew breast cancer cells (MCF-7, T-47D, ZR-75-1) known to proliferate under estrogenic stimulation in phenol red-free DMEM containing human serum and concentrations of BPA or BPA-DM ranging from 10(-8)M to 5 x 10(-6)M. After 1 week, plates were harvested for crystal violet or sulforhodamine-B assays, and the optical densities of groups of treated cells were compared with values from control cells. At concentrations at or above 10(-6)M, both BPA and BPA-DM significantly increased cell proliferation (p < 0.05), comparable to the increase seen with 10(-9)M of estrogen. Flow cytometric methods demonstrated that these mitogenic effects occurred within 24 h of exposure to estrogen, BPA, or BPA-DM. The increase in DNA synthesis was analogous to that seen with estrogen stimulation. Thus, we confirmed that BPA and BPA-DM cause cell proliferation at micromolar concentrations that exceed the effective concentrations of estrogen by 1 to 10,000-fold.

Benzhydryl Compounds↗
PubMed1989

Effects of dental medicaments on examination glove permeability.

Dental care providers wear gloves for all clinical procedures. This study was designed to assess the intactness of examination gloves after exposure to commonly used agents. Finger portions from latex and vinyl examination gloves were sealed to syringe barrels and exposed to alcohol, eugenol, a surface disinfectant, cavity varnish, or commercial mouth wash. Tritiated water was introduced into the finger-tip portion, which was suspended in a vacuum flask containing distilled water. Aliquots of water were withdrawn from the flask at intervals of 5 minutes to 8 hours and analyzed for transfer of radioactivity through the glove tip. Treatment with agents such as eugenol and cavity varnish resulted in significant leakage after 5 to 15 minutes. Although some agents apparently quickly damaged the gloves, leaks developed in untreated gloves with time. Results suggest that visibly intact gloves may have developed microleaks and that changing gloves during long clinical procedures may be indicated.

Dental Cavity Lining↗
PubMed1986

Effective delivery systems for prolonged fluoride release: review of literature.

Controlled-release delivery systems have been investigated for use in fluoride therapy as a result of their ability to control the rate and site of fluoride release. Both sustained-release fluoride delivery systems and controlled-release fluoride preparations have been developed, including sustained-release fluoride tablets, fluoride-releasing polymers, microencapsulated fluoride in aerosols, and membrane-controlled fluoride reservoirs. Laboratory and clinical studies have confirmed the ability of these preparations to produce high levels of fluoride in saliva and plaque without toxic or adverse side effects. From these studies, it appears that controlled-release fluoride delivery systems have great potential as effective anticaries agents in cariesprone populations.

Aerosols↗
PubMedDate not supplied

Dental caries and fluorosis among children in a rural Georgia area.

PURPOSE: This IRB-approved study compared the caries experience, fluorosis prevalence, and plaque and salivary fluoride concentrations ([F]) in middle school (MS; N = 51) and elementary school (ES; N = 144) children residing in nonfluoridated and fluoridated communities in rural Georgia. All participants were exposed to fluoridated water at school (0.5-1.2 ppm), some received that level at home, and others received home water with < 0.1 ppm F. METHODS: Subjects' parents completed a questionnaire regarding fluoride exposure. Children were examined at school by two calibrated dentists. RESULTS: No significant differences were seen in DMFS+dfs between children with or without fluoridated home water, nor for those with or without fluorosis. MS children with non-fluoridated home water had lower mean salivary [F] values than MS children with fluoridated home water. No differences were found among MS and ES children in mean plaque [F] for those with or without fluorosis. CONCLUSIONS: Home water fluoridation had little effect on the variables measured. These findings appear to be due to fluoride exposure from fluoridated dentifrices, fluoridated drinking water at school, and the fluoride "halo" effect.

Child↗
PubMedDate not supplied

What parents should know about estrogen-like compounds in dental materials.

The use of pit and fissure sealants has been reported to increase exposure to xenoestrogens. Because these estrogen-mimics are suspected of having many deleterious effects in animals, and perhaps humans, several types of studies were undertaken by our Biocompatibility Group. We confirmed that bisphenol A (BPA) and bisphenol A dimethacrylate (BPA-DM) have proliferative effects in cells with high levels of estrogen receptors. However, BPA was not detected by our group in American-made sealants, and BPA-DM was detectable in only a few. In addition, the surface layer of the sealant can be treated to reduce the possibility of unpolymerized BPA-DM being left on the tooth. We believe it is important to reassure parents that their children are less likely to be exposed to BPA from sealants than from the ingestion of soft drinks or canned food.

Animals↗
PubMedDate not supplied

The influence of practice type, region, and age on treatment recommendations for primary teeth.

The purpose of this study was to investigate dentists' treatment recommendations for interproximal surfaces of primary molars based on the type of practitioner (general dentist or pediatric dentist), geographic location, and age of practitioner. Simulated cases, which included histories and pictures of bite-wing radiographs, were mailed to a random sample of 2000 general dentists and 1000 pediatric dentists. Dentists were asked to select their treatment recommendations for eight cases involving the interproximal surface of a specified primary molar. The return rate was 42% (1245) overall, with 36% (723) from general dentists and 52% (522) from pediatric dentists. An amalgam restoration was recommended most often for these eight cases. Dentists in the age 60+ category and pediatric dentists were more likely to recommend treatment for smaller interproximal lesions. Composite resins were recommended infrequently; however, dentists in the 60+ age category and dentists in the Northeast and Southwest were somewhat more likely to recommend composite resin than younger dentists, or dentists in other geographic locations. Dentists in the 40-49 age range, pediatric dentists, and dentists in the Southwest were the most likely to recommend stainless steel crowns. These simulated cases demonstrate differences and similarities in the treatment recommendations for interproximal lesions on primary molars based on age, practice type, and region.

Adult↗
PubMedDate not supplied

Gender differences in the characteristics of dental services provided for children.

The purpose of this project was to describe the differences and similarities in the practice of dentistry for children by male and female dentists. A once-mailed survey with a series of questions regarding the characteristics of their dental practices was sent to a random sample of 3,000 dentists. There were 1,154 useable responses (39 percent). Approximately 8 percent of the respondents were women, which is representative of the percentage of female dentists practicing in the United States. Chi square analysis was employed. There were differences in the practice characteristics of the male and female dentists responding to this survey. The female respondents were: significantly younger; had been in practice for a shorter period of time; more likely to be employees rather than solo practitioners; more likely to treat younger patients; less likely to do comprehensive orthodontic treatment and more likely to use physical restraints than their male counterparts.

Adolescent↗
PubMedDate not supplied

Enamel uptake and patient exposure to fluoride: comparison of APF gel and foam.

This crossover study with 46 child dental patients compared two topical APF products, a gel and a foam, with respect to the amounts of product and fluoride (F) applied, salivary F concentrations, and enamel F uptake. Half the subjects were treated for 4 min with the gel first and the other half with the foam. After approximately 16 days, each patient received a second treatment using the other product. An acid-etch enamel biopsy was performed and whole saliva samples were collected before and after each treatment. Significantly less F was applied to the teeth and retained by the subjects when the APF foam was used. Salivary F concentrations after treatment with the gel were higher than after treatment with the foam. The differences in enamel F uptake at both 15 min and 16 days after the APF applications, however, were not significant. We concluded that: 1) the two products are equivalent with respect to enamel F uptake; 2) only about one-fifth as much of the foam product is required for adequate coverage of the teeth, which significantly reduces F exposure and retention by the patient.

Acidulated Phosphate Fluoride↗
PubMedDate not supplied

In vitro effect of human saliva on the output of fluoride from controlled-release devices.

This study was designed to determine the in vitro fluoride output from controlled-release devices in stimulated, whole human saliva, and to assess changes in the salivary calcium concentration following immersion of the devices. Twenty fluoride (F) controlled-release devices of the hydroxyethyl methacrylate (HEMA)/methyl methacrylate (MMA)-type were employed. Each was designed to release 1-2 mg F per day. All devices were placed individually in 10.0 ml of deionized water for 3 days to assess baseline F output. Seven devices with markedly high or low output were discarded. During days 4-13, three of the remaining 13 devices were placed individually in 10.0 ml of stimulated, whole saliva donated by three volunteers. All devices were returned to deionized water during days 14-17. All solutions were replaced daily with fresh solutions, and each test tube was inverted once every 24 hr. The study was conducted at 19-21 degrees C. Fluoride concentration of the deionized water and human saliva was assessed by ion-specific electrode; calcium concentration of the saliva was assessed pre- and postimmersion by flame atomic absorption spectrometry. The fluoride output of the devices placed in saliva decreased to 36% of their baseline rates (P < 0.001). The calcium concentration of the human saliva decreased from a mean preimmersion value of 3.58 mg/100 ml (+/- 0.63 SD) to a postimmersion value of 2.64 (+/- 1.12 SD; P < 0.001). These results suggest an interaction between the fluoride released by the devices and calcium in the saliva.(ABSTRACT TRUNCATED AT 250 WORDS)

Apatites↗
PubMedDate not supplied

Dentists' perceptions of selected characteristics of their child patients.

The purpose of this project was to examine the perceptions of both general and pediatric dentists regarding selected characteristics of the children they treat. A survey including questions on patients' ages, caries activity estimates, and types of patients treated was mailed once to a national random sample of 2,000 general and 1,000 pediatric dentists. The respondents provided a reasonable distribution by age and location, with the majority (69%) in practice more than 10 years. The pediatric dentists who responded perceive that they treat a younger population of child patients with more caries activity (P < 0.001), except in those patients older than 12 years. They also perceive that their patients pools include a larger percentage of patients with handicapping conditions (P < 0.01), behavior problems (P < 0.001) and patients who require treatment with general anesthesia (P < 0.001) than do the general dentists.

Adolescent↗
PubMedDate not supplied

An outcomes assessment of 15 years of patient care experiences in predoctoral pediatric dentistry.

The purpose of this study was to examine the trends in numbers, demographic characteristics, and treatment history of pediatric dental patients under the care of dental students over the period 1980 through 1994. Data were collected for: exams, sealants, surfaces of amalgam, composite resin surfaces, pulpotomies, stainless steel crowns, and extractions. Correlations were done across the 15-year period to determine significant trends over time. During the 15-year period, the average number of patient visits required for each student to complete the requisite number of patients, declined from 45 appointments to complete 10 patients in 1980, to 35 visits to complete 13 patients in 1994. Over time, the numbers of amalgam surfaces, pulpotomies, extractions and stainless steel crowns decreased significantly, while the number of composite resin surfaces increased (P < 0.05). Based on a previous outcome assessment that indicated declining numbers of procedures performed between 1980 and 1985, the required number of patients treated per student was raised from 10 to 13, beginning with the 1986 class.

Adolescent↗
PubMedDate not supplied

Perceptions associated with dentists' decisions to report hypothetical cases of child maltreatment.

The purpose of this study was to examine case-specific perceptions associated with dentists' decisions to report hypothetical cases suggestive of child maltreatment. Surveys were mailed to 500 general dentists (GDs) in Georgia and all 200 pediatric dentists (PDs) in Georgia and Florida. The GDs were chosen from a pool of 1500 by a stratified randomization scheme. Each survey contained two brief vignettes suggestive of, but not conclusive for, child neglect and abuse. Identical questions followed each vignette that were designed to assess five perceptions of the incident and whether the respondent would be likely to report the case. Responses were received from 185 GDs (37%) and 103 PDs (51.5%), for a total of 288 (41.1%). A majority of respondents considered each vignette to be serious, but only a minority believed that they were required to report the neglect (7.3%) and the abuse (33.7%) vignettes. The percentages of likely reporters of the neglect (n = 28) and abuse (N = 103) vignettes were 9.7 and 36%, respectively. No significant differences were noted in the response patterns of GDs and PDs. Decisions to report child maltreatment described in the vignettes were associated with perceptions of 1) the seriousness of the incident, 2) the incident being defined as neglect or abuse, and 3) a requirement to report. The possibility that a maltreatment report would have a negative impact on the child was associated with a decision not to report. The perception that a report would have a negative impact on the family was common among likely reporters and nonreporters.

Attitude of Health Personnel↗
PubMedDate not supplied

Demographic, educational, and experiential factors associated with dentists' decisions to report hypothetical cases of child maltreatment.

The purpose of this study was to examine demographic factors associated with dentists' decisions to report hypothetical cases suggestive of child maltreatment. Surveys were mailed to 500 general dentists (GDs) in Georgia and all 200 pediatric dentists (PDs) in Georgia and Florida. The general dentists were chosen from a pool of 1500 by a stratified randomization scheme. Each survey contained two brief vignettes suggestive of, but not conclusive for, child neglect and abuse. Respondents were asked about their likelihood of reporting each vignette. General demographic questions were asked about the population served by the dentist, the year of dental degree and speciality certificate acquisition, and gender of the respondent. Further questions were asked about the individual's exposure to continuing education in child maltreatment, knowledge of legal requirements to report and the agency to which reports should be directed, and experience with suspected and filed cases. Responses were received from 185 GDs (37%) and 103 PDs (51.5%), a total of 288 (41.4%). PDs had more practitioners in larger communities and had more female respondents. PDs were more likely to answer yes to the questions about education/experience with child maltreatment. Factors associated with likely reporting of neglect were: 1) serving communities with populations < or = 100,000; 2) PDs acquiring specialty certificates after 1980; 3) being female; 4) exposure to continuing education; 5) having suspected cases in practice; and 6) having filed a maltreatment report. Factors associated with likely reporting of abuse were: 1) PDs acquiring specialty certification after 1980 and 2) self-reported recognition of the legal obligation to report.

Attitude of Health Personnel↗