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Biomedical subjects

R E Corpron

Publications and source records attributed to R E Corpron.

At least 19 recordsLinked to original sources
PubMed1994

Dose related remineralization using intraoral fluoride-releasing devices in situ.

Dose-related remineralization of enamel lesions was studied in situ. Enamel specimens with subsurface lesions were mounted on lower molars bilaterally and exposed to five regimens: (A) control with a F-free dentifrice three times daily; (B) NaF dentifrice brushed three times daily; (C) fluoride-releasing device (FRD; 0.07 mg F/day release rate) plus F-free dentifrice; (D) FRD (0.232 mg F/day) plus F-free dentifrice, F/day and (E) FRD (0.232 mg/F/day) plus NaF dentifrice. Resting and stimulated saliva samples were obtained for salivary flow and F content determinations. Twenty-eight subjects participated in this double-blind, random-assignment crossover study. After 50 days the enamel specimens were recovered, sectioned, microradiographed, and scanned with image analysis. Regimens D and E demonstrated approximately 30% additional remineralization as compared with to controls, and regimens B and C showed 13.7 and 10.5% increased remineralization as compared with to controls. The increased remineralization of the regimens generally paralleled the increase in salivary F and clearly demonstrated a dose-related response which was some threefold in relation to release rate, salivary F, and percent remineralization.

Adult↗
PubMed1994

In situ remineralization of root surface lesions using a fluoride chewing gum or fluoride-releasing device.

The in situ remineralization of early root surface lesions was studied using a fluoride-releasing device (FRD) or a fluoride chewing gum. Root specimens with subsurface lesions were mounted in removable lower appliances in 6 adult subjects. Test groups chewed five sticks/day (0.1 mg F/stick) or one FRD (0.5 mg F/day release rate) was mounted in the midline of the appliance. A fluoride-free dentifrice was used three times/day for each 21-day control and the two test regimens. Separate root lesions were used to measure fluoride uptake or changes in mineral content by quantitative microradiography. Comparable values for percent remineralization for both FRDs and F gum were higher than controls, and the F uptake for FRDs exceeded both the F gum and controls (p = 0.05).

Adult↗
PubMed1993

In situ remineralization of subsurface enamel lesion after the use of a fluoride chewing gum.

In situ remineralization of early enamel lesions by a fluoride chewing gum was studied. Human enamel specimens with subsurface lesions were mounted in removable lower appliances for 6 adults. Subjects used a F-free dentifrice 3x/day and chewed five sticks/day for the F gum group (0.1 mg F/stick) or five sticks of sugarless gum. No gum was chewed for controls. Surface microhardness was performed on: (1) sound enamel; (2) lesions; (3) after intraoral exposure, and (4) after acid-resistance testing (ART). Separate specimens were etched and measured for F uptake and image analyses on microradiographs were performed for all regimens. delta Z values were calculated and converted to percent of mineralization. Values for F gum were significantly higher (p > 0.05) than non-F gum and controls for ART, percent remineralization, and F uptake up to 70 microns depth.

Adult↗
PubMed1993

In situ remineralization of enamel lesions using continuous versus intermittent fluoride application.

Remineralization of early enamel lesions was studied in situ using a F chewing gum or a F-releasing device (FRD). Enamel specimens with subsurface lesions were mounted in removable lower appliances in 6 adults. A F-free dentifrice was used for all regimens. Test groups chewed five sticks/day (0.1 mg F/stick), or one FRD (0.5 mg F/day) was mounted in the midline of the appliance. The microhardness was measured after the 21-day intraoral exposure, and in vitro acid resistance testing was performed. Separate specimens were used to measure F content or changes in mineral density. Comparable values for both F gum and FRDs were higher (p > 0.05) than controls for acid resistance testing and percent remineralization. The F content for FRDs exceeded that of both F gum and controls.

Adult↗
PubMed1992

Comparison of fluoride profiles by SIMS with mineral density of subsurface enamel lesions treated intra-orally with a fluoride-releasing device.

A variety of intra-oral model systems has evolved which allows for the study of remineralization of coronal and/or root-surface lesions following application of topical fluoride (F) agents. The problem of interpretation of the results has led to a variety of analytical methods (i.e., microhardness, F biopsy, microradiography, and polarizing light microscopy), each of which provides important but limited information related to the overall understanding of remineralization. Microhardness measures change in mineral content which is more precisely localized by microradiography and polarized light microscopy. F biopsy allows for assessment of the F uptake of lesions, but does not suggest the chemical state of the F. Previous work has demonstrated that patterns of mineral deposition during remineralization do not necessarily parallel the F uptake profiles, and fluoridated apatites cannot be distinguished from non-specifically-adsorbed F (Clark et al., 1988). Because artificial lesions demonstrate variations in depth and mineral content, complementary analytical methods that demonstrate profiles of both F content and mineral density curves on the same section are needed so that the process of remineralization can be more clearly understood. This study used secondary ion mass spectrometry (SIMS) for F profiles and quantitative microradiography for assessment of mineral deposition on the same section. These state-of-the-art methods demonstrate the precision with which information about remineralization can be obtained. Subsurface lesions in human enamel specimens were developed by immersion in 0.1 M lactate buffer with 1% CMC at a pH of 4.5 for 48 h.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

In vivo study of fluoride chewing gum for the remineralization of human root lesions.

The purpose of this study was to study the efficacy of a fluoride-containing chewing gum (0.1 mg F/stick chewed 5 x/day) in the remineralization of artificial caries lesions in abraded root surfaces compared to sorbitol-containing chewing gum and a no gum control group in vivo. Root specimens were cut from human root surfaces and polished. The specimens were demineralized in a buffered lactate solution with low concentration of fluoride in order to preserve an intact surface layer. Six healthy subjects wore mandibular Hawley-type appliances containing up to fourteen slabs for each of one control and two experimental periods. The experimental protocol included chewing five pieces of gums per day and brushing with fluoride-free dentifrice for each 21 days period. All three regimens were analyzed for fluoride uptake and microradiography. The results indicate that fluoride-containing chewing gum has a highly significant fluoride uptake and remineralization compared to sorbitol gum and control regimens, suggesting that fluoride chewing gum may provide another vehicle for fluoride delivery.

Chewing Gum↗
PubMed1988

Comparison of the effects of two topical fluoride regimens on demineralized enamel in vivo.

The purpose of this investigation was to study the intra-oral remineralization of acid-softened enamel by a NaF dentifrice compared with that from a combination of topical F agents. Bovine enamel slabs were demineralized with 0.1 mol/L lactic acid at pH 4.0 for 14 hr and then mounted in a removable mandibular appliance. Control slabs were worn for 96 hr by seven adult males who brushed daily with a F-free dentifrice. Test slabs were brushed with a NaF dentifrice 4 x/day or with the same dentifrice 4 x/day and a 0.02% APF mouthrinse and a 0.4% SnF2 gel which were applied once/day for three days. The natural dentition was also brushed with the NaF dentifrice during both test periods. Microhardness testing was performed on sound enamel, and after acid-softening, intra-oral exposure (IOE), and acid resistance testing (ART) in 0.01 mol/L lactic acid at pH 4.0 for 24 hr. Control and test slabs were etched with 0.5 mol/L HC1O4 for from 15 to 60 sec. The F content was measured with a F electrode and PO4 by spectrophotometry. Contact microradiography and image analyses were performed on control and test slabs so that changes in mineral content resulting from treatment could be assessed. Both test groups were significantly harder after both IOE and ART than were controls, but no differences appeared between the effects of the two test groups. The F content of control slabs was significantly less than that of both test groups, and the combination-treated slabs showed greater F than did the dentifrice-treated slabs.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Intra-oral effects on acid-softened enamel of NaF lozenges administered in divided daily doses.

The purpose of this investigation was to study the intra-oral effects of multiple daily applications of NaF lozenges upon acid-softened enamel. Bovine enamel slabs were softened with 0.1 mol/L lactate buffer at pH 4.0 for 14 hrs and subsequently mounted in a mandibular removable Hawley appliance. Control slabs were worn for seven days by eight adult male subjects who brushed their natural dentition daily with a fluoride-free dentifrice. Test slabs were exposed to one 0.55-mg NaF lozenge (0.25 mg F) 4x/day for seven days and the natural dentition brushed with a fluoride-free dentifrice. The efficacy of 0.25-mg F lozenges used 4x/day over that of a 1-mg F lozenge administered 1x/day was established by a pilot study with two subjects. Microhardness testing was performed after intra-oral exposure (IOE) and following immersion in 0.01 mol/L lactate buffer containing Ca and PO4 for 24 hrs at a pH of 4.0. Fluoride uptake was measured on separate control and test slabs after KOH wash and after acid-resistance-testing (ART). Recovery of microhardness following IOE was 40.9% for controls and 53.9% for treated slabs, while control slabs retained 1.3% resistance to ART, compared with 25.6% for test slabs. The F content of the control slabs was significantly less than that of lozenge-treated and lozenge-treated-ART slabs throughout the depth of the lesion. The F content of the lozenge-treated-ART slabs was significantly less than that of the lozenge-treated slabs only at the 0-5-microns depth.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1986

In vivo effects of a SnF2 gel on acid-softened enamel.

The purpose of this investigation was to study the intra-oral rehardening of acid-softened enamel and fluoride uptake from SnF2 gel. Bovine enamel slabs were softened with 0.1 mol/L lactate buffer at pH 4.0 for 14 hrs and then mounted in a mandibular removable Hawley appliance. Control slabs were worn for 96 hrs by seven adult males whose teeth were brushed daily with a fluoride-free dentifrice. Test slabs were exposed once/day to 0.4% SnF2 gel. The gel was swabbed onto the slabs for one minute before being replaced in the mouth unrinsed. The natural dentition was brushed 4 X /day with a fluoride-free dentifrice. Microhardness testing was performed after intra-oral exposure (IOE) and after acid-resistance-testing (ART) following immersion in 0.01 mol/L lactate buffer for 24 hrs at pH of 4.0. Fluoride uptake was measured on separate controls, test slabs, and test slabs after ART, with 0.5 mol/L HClO4 etches of from 15 to 60 sec. The F content was measured with a F-ion-specific electrode and the phosphate content by spectrophotometry. Following IOE, microhardness recovery was 35.6% for control and 37.9% for test slabs, and control slabs retained 1.4% resistance to acid, as compared with 18.6% for the test slabs. The F content of control slabs was significantly less than that of SnF2-treated slabs from 5 to 60 micron in depth, and the F content of SnF2-treated slabs after ART was significantly less at depths of from 5 to 35 micron than that of SnF2-treated slabs not exposed to ART. Both control and SnF2 enamel slabs demonstrated rehardening after IOE, but only SnF2-treated enamel retained a significant fraction of that rehardening after ART.

Adult↗
PubMed1986

Intraoral effects of a fluoride-releasing device on acid-softened enamel.

Among the anticaries benefits of fluorides is the remineralization of incipient carious lesions. There is increasingly convincing evidence that low-potency fluoride agents applied frequently are effective in remineralizing early carious lesions. This study of in vivo remineralization used an intraoral appliance with demineralized enamel slabs mounted in the appliance and an innovative method of fluoride delivery, the fluoride-releasing device, which releases a controlled amount of fluoride (0.3 mg fluoride every 24 hours) on exposure to saliva. After control and treatment periods of 7 and 30 days, the enamel specimens were removed from the appliance and evaluated for microhardness, acid resistance, and fluoride uptake. The treated specimens significantly exceeded the values of their corresponding controls in all parameters measured, indicating that considerable remineralization of the treated enamel had occurred at both 7 and 30 days. Although the longer period of treatment produced greater results, considerable effects were observed after 7 days. This model system provided for an in vivo environment to study the effects of treatment of the FRD and allowed for subsequent recovery of the enamel specimens for evaluation. The results of this study are encouraging with respect to the efficacy of a fluoride-releasing device but indicate that subsequent clinical testing of the effects of FRDs on incipient carious lesions in the natural dentition of human subjects is necessary.

Adult↗