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J S Wefel

Publications and source records attributed to J S Wefel.

At least 37 records · Page 2Linked to original sources
PubMed1997

Remineralization of root surfaces demineralized in solutions of differing fluoride levels.

The beneficial effects of fluoride on enamel have been well documented. However, limited data are available concerning the amount of fluoride required for beneficial effects on tooth root. Although studies have shown that fluoride inhibits root demineralization, the aim of this study was to investigate the location, extent and amount of remineralization on root dentin substrates after demineralization has occurred. The root surfaces of extracted human teeth were demineralized in a pure chemical buffer containing varying concentrations of sodium fluoride. After this lesion initiation, the same root sections were then placed into a remineralizing solution. The root sections were characterized after demineralization, and again after remineralization, by polarized light microscopy (PLM) and microradiography (MRG). Lesion depths after the demineralization phase were found to be inversely proportional to the fluoride concentration. When fluoride was present, bands or lines within the body of the lesion were observed with PLM and MRG. Using quantitative MRG, variations in mineral content and distribution were recorded. Examination of the root sections after the remineralization phase showed remineralization to have occurred on the remaining mineral and not on organic matrix devoid of mineral. The amount and location of mineral deposition may be of great significance in the arrestment and treatment of in vivo root surface caries.

Buffers↗
PubMed1997

Fluoride concentrations of infant foods.

Infants who ingest high amounts of fluoride can be at risk of dental fluorosis. The authors analyzed the fluoride concentration of 238 commercially available infant foods. Fluoride concentrations ranged from 0.01 to 8.38 micrograms of fluoride per gram, with the highest fluoride concentrations found in infant foods containing chicken. Infant foods, especially those containing chicken, should be considered when determining total fluoride intake.

Edible Grain↗
PubMed1997

The effects of microabrasion on demineralization inhibition of enamel surfaces.

Microabraded enamel acquires a highly polished surface of mineralized tissue. The purpose of this study was to determine if microabraded enamel surfaces are more resistant to demineralization. Twenty extracted permanent incisors were used in the experiment. Four treatment modalities were investigated: (1) microabrasion in conjunction with a topical fluoride treatment, (2) topical fluoride treatment, (3) microabrasion, and (4) no treatment. All surfaces, following their respective treatment regimen, were stored in artificial saliva for 2 months and then exposed to an artificial caries system for 5 days. Teeth treated with microabrasion followed by a 4-minute application of 1% neutral topical sodium fluoride exhibited significantly less enamel demineralization when subjected to an artificial caries challenge than did teeth that underwent microabrasion alone, topical fluoride treatment alone, or no treatment at all.

Analysis of Variance↗
PubMed1997

Effect of enamel microabrasion on bacterial colonization.

PURPOSE: To determine if microabraded surfaces inhibit Streptococcus mutans colonization. MATERIALS AND METHODS: Ten extracted molars were obtained and sectioned in half mesio-distally. The mesial side was treated with microabrasion (PREMA Compound). The distal surface was designated as the control site. A plastic tube was secured on each surface with resin composite, exposing a surface of 13.2 mm 2. S. mutans 10,499 was cultured in TSB-YE supplemented with 5% sucrose and 2.5% glucose was added to each secured site in addition to 50 microliters of cell suspension. Samples were incubated in a 5% CO2 chamber for 7 days at 37 degrees C. Samples were taken from each site, incubated with dextranase (75 micrograms 1 ml), sonicated, and vortexed to disrupt cellular aggregates as much as possible. Samples were then plated on Mitis-Salivarius agar using a spiral plating system. Enumeration of numbers of colonizing bacteria was achieved following standard spiral plating system methodology. RESULTS: The mean for the microabraded group was 1.12 x 10(2) cfu/tooth and for the control it was 1.15 x 10(4). Analyzing the data revealed a significant difference (P = 0.0188).

Colony Count, Microbial↗
PubMed1996

Preparation and measurement of artificial enamel lesions, a four-laboratory ring test.

Transversal microradiography is the most widely accepted method used to study changes in mineral content profiles. In spite of its widespread use, relatively little information is available on its validity and reproducibility. Following the recommendation of the Consensus Conference on Intraoral Model Systems, this study was designed to explore reproducibility of lesion analysis within a laboratory and comparability of analysis among various laboratories. Incipient enamel lesions were produced by four research groups using both a common ('standard') and a local ('preferred') protocol. Sections were produced by each group and allocated to 'mixed' bags of specimens, which were analysed by the groups. With the chosen scheme some sections were analysed six times by the same group (as an internal reference standard) while others were analysed by all four groups. The data for the mineral content profiles were expressed as the integrated mineral loss (IML) value and lesion depth. The results showed the lesions produced with the standard protocol to be in the range 2,000-3,000 vol% mineral x microns for IML. The IML of the lesions produced with the preferred protocol varied between 1,800 and 6,300 vol% mineral x microns. Variation in IML values could be attributed to the biological variation between lesions, but also to time (of microradiograph production) and measurement effects, calibration of the magnification of the specimens, and the parameters used in the algorithm to calculate IML. Some of these parameters also affected the lesion depth. It is advised to standardise (or at least report) the method of calculation of IML, and to include a reference lesion between analyses in a longitudinal study as an internal standard. With the data produced, it was calculated that the number of lesions required to differentiate between preventive treatments varied substantially among laboratories. The recommendations given will improve the power of the screening methods for caries-preventive agents for which microradiography is an essential analytical method.

Analysis of Variance↗
PubMed1995

Comparisons of in vitro root caries models.

The purpose of this article is to compare various model systems for the production of in vitro root caries and to assess their ability to simulate the naturally occurring root caries process. Partially saturated buffer models and gel models were evaluated using polarized light microscopy and both qualitative and quantitative microradiography. All model systems showed very similar lesion formation when examined under polarized light. When microradiographs were compared, the systems which contained fluoride, showed clear radiopaque bands within the lesion. The bands, which occurred only in the presence of fluoride, appeared to be due to remineralization. When using an in vitro system that simulates the natural root caries process, it is imperative to understand the components of the particular model, as well as its limitations, and to be aware of the need for more than one evaluative technique.

Buffers↗
PubMed1995

Infants' fluoride intake from drinking water alone, and from water added to formula, beverages, and food.

In infants, the majority of total ingested fluoride is obtained from water, formula and beverages prepared with water, baby foods, and dietary fluoride supplements. Few studies have investigated the distribution of fluoride intake from these sources among young children at risk for dental fluorosis. The purpose of this study was to assess estimated water fluoride intake from different sources of water among a birth cohort studied longitudinally from birth until age 9 months. Parental reports were collected at 6 weeks, 3 months, 6 months, and 9 months of age for water, formula, beverage, and other dietary intake during the preceding week. Fluoride levels of home and child-care tap and bottled water sources were determined. This report estimates daily quantities of fluoride ingested only from water--both by itself and used to reconstitute formula, beverages, and food. Daily fluoride intake from water by itself ranged to 0.43 mg, with mean intakes < 0.05 mg. Water fluoride intake from reconstitution of concentrated infant formula ranged to 1.57 mg, with mean intakes by age from 0.18 to 0.31 mg. Fluoride intake from water added to juices and other beverages ranged to 0.67 mg, with means < 0.05 mg. Estimated total daily water fluoride intake ranged to 1.73 mg fluoride, with means from 0.29 to 0.38 mg.

Beverages↗
PubMed1995

Infants' fluoride ingestion from water, supplements and dentifrice.

Concerns about dental fluorosis and the paucity of detailed fluoride intake data prompted this longitudinal study of fluoride intake in infants from birth to 9 months of age. On average, water fluoride intake greatly exceeded that from dietary fluoride supplements or fluoride dentifrice. However, fluoride supplements and dentifrice contributed substantial proportions of fluoride intake among children using them. Some children had estimated fluoride intake from water, supplements and dentifrice that exceeded the recommended "optimal" intake (a level that has yet to be determined scientifically). Practitioners should estimate fluoride ingestion from all these sources if considering systemic fluoride supplementation.

Animals↗
PubMed1995

De/remineralization from sodium fluoride dentifrices.

PURPOSE: To test the demineralization/remineralization effects of sodium fluoride dentifrices using an in situ single-section crown model system. MATERIALS AND METHODS: A fluoride dose response was evaluated using 0, 1100 and 2800 ppm F-, along with the effects of an enhanced fluoride delivery system (polyampholyte-NaF). The single-section crown model was employed with supervised toothbrushing twice a day. At the end of each 1-month study leg, sections were removed and replaced with new sections for the next leg. Both before and after the double-blind, crossover portion of the study, sections were evaluated by polarized light microscopy and microradiography. The change in mineral content of the enamel and root lesions was analyzed by ANOVA with a Waller-Duncan K-Ratio Test post hoc. RESULTS: The placebo dentifrice group showed a loss of mineral and was statistically different from all groups. The fluoride dentifrices showed increasing amounts of enamel mineral gain, with increasing fluoride concentration. The polyampholyte-NaF delivery system with 1100 ppm F- was equivalent to the 2800 ppm F- dentifrice. Root lesions gave similar rank-order results although all treatments showed demineralization or mineral loss.

Adult↗
PubMed1994

In vitro bond strengths and SEM evaluation of dentin bonding systems to different dentin substrates.

In comparison to enamel, bonding to normal dentin is a greater challenge because of its organic constituents, fluid-filed tubules, and variations in intrinsic composition. Bonding to sclerotic dentin is even more difficult. To evaluate the shear bond strengths of four adhesive systems to dentin substrates with different levels of mineralization, 120 extracted human teeth were randomly assigned to three groups (n = 40). After mid-coronal dentin was exposed, groups of specimens were artificially hypermineralized by immersion in a remineralizing solution, demineralized by means of an acetic acid demineralizing solution, or stored in distilled water to model sclerotic, carious, and normal dentin, respectively. Resin composite was bonded to dentin by use of commercial adhesive systems. After the specimens were thermocycled, shear bond strengths were determined in an Instron universal testing machine. Dentin substrates and resin/dentin interfaces were examined by SEM. For each adhesive system, the mean shear bond strength to normal dentin was significantly higher than that to either of the other substrates. Shear bond strengths to hypermineralized dentin were significantly higher than those to demineralized dentin with all adhesives except Prisma Universal Bond 3.

Analysis of Variance↗
PubMed1994

Root caries histopathology and chemistry.

This paper reviews the histopathology of root surface caries, and the effect of fluoride on the root caries process. The root caries process may be defined as a dynamic equilibrium similar to enamel caries. The caries process produced acid demineralization in exposed root surfaces and resulted in a lesion body when viewed in the light microscope. A relatively intact surface layer was not always present unless root caries was observed. In the absence of fluoride, a significant surface layer was left devoid of mineral but with intact collagen. Fluoride helped to prevent lesion formation and produced radiodense banding within the lesions in in vitro models. Remineralization occurred on the remaining mineral and not on the collagen matrix devoid of mineral. The conversion of active to inactive root caries requires the formation of a mineralized layer and implies the loss of surface tissues and contour in the clinical situation.

Animals↗
PubMed1993

A critical review of the relative anticaries efficacy of sodium fluoride and sodium monofluorophosphate dentifrices.

While there is broad consensus in the research community that fluoride dentifrices provide important anticaries benefits, debate still remains as to the most efficient form of fluoride used in toothpastes. Recently, the authors of this paper collaborated as part of a scientific advisory group whose objective was to comprehensively review all clinical information available comparing the anticaries efficacy of the two agents most widely used in fluoridated toothpastes, sodium fluoride (NaF) and sodium monofluorophosphate (SMFP). This review included a detailed analysis of each published study pertinent to the question, a comprehensive meta-analysis of all available clinical findings, and an epidemiological assessment of how anticaries benefits of dentifrices may be anticipated to propagate with time. Overall, the use of meta-analysis of head-to-head clinical comparisons between the two fluoride-active systems was found to be the most valid means for comparing the relative efficacy of NaF and SMFP dentifrices. Results of this analysis demonstrated that NaF was significantly more effective than SMFP in preventing caries (p < 0.01). While the numerical difference in efficacy between NaF and SMFP measured between 5 and 10% (total DMFS) over a 2- to 3-year clinical period, this could be expected, on theoretical grounds, to propagate to substantially larger differences (e.g. 10-20%) over 10-20 years. Hence, the difference in efficacy between these two actives was judged to be clinically important as well as statistically significant. Based upon these findings the authors recommend that NaF be used as the active system in fluoridated dentifrices whenever practically feasible. However, the authors caution that this recommendation pertains to the formulation of NaF in highly compatible abrasive systems, which must be demonstrated by critical evaluation of ionic fluoride within formulations for stability, availability and bioavailability. One additional recommendation emanating from this review is that important improvements must be made in the design, execution and reporting of future caries clinical trials in order to bring these important methods up to scientifically acceptable standards.

Adolescent↗
PubMed1993

The antimicrobial activity of Prevention mouthrinse.

Prevention mouthrinse was designed to serve as a vital supplement to normal oral hygiene procedures. To determine the antimicrobial potency of this mouthrinse, minimal inhibitory concentrations (MICs), bactericidal kinetics, and short-term exposure studies were conducted. A spectrum of oral microorganisms was employed in this investigation: Streptococcus sanguis, Streptococcus anginosus, Streptococcus mutans, Actinomyces viscosus, Actinobacillus actinomycetemcomitans, Fusobacterium nucleatum, Eikenella corrodens, Porphyromonas gingivalis, Serratia marcescens and Candida albicans. Microorganisms were cultured in standard enriched media and under appropriate atmospheric conditions. Inhibition assays were conducted in tubes, with each mouthrinse dilution assayed in triplicate. MIC determinations revealed that all of the microorganisms studied were highly susceptible to Prevention mouthrinse, with MICs ranging from 16-fold to 128-fold dilutions. Bactericidal kinetics assays showed rapid killing of the test organisms in the presence of the mouthrinse. Brief (5-minute) exposure of S. mutans to 8-fold diluted mouthrinse resulted in a substantial delay in growth. Under the constraints of this type of study, Prevention mouthrinse exhibited potent antimicrobial activity against all of the microorganisms studied. We support the notion that Prevention mouthrinse may be a valuable supplement to normal oral hygiene procedures. A 6-month clinical trial assessing the in vivo efficacy of Prevention mouthrinse is currently being conducted.

Actinomyces viscosus↗
PubMed1992

An intra-oral single-section demineralization/remineralization model.

This paper reviews the use of our intra-oral crown single-section model for the evaluation of in situ demineralization and remineralization. The model uses normal, healthy adults who are in need of a gold crown. A slot is placed in the working crown which can hold 3-4 single sections. A typical experiment would use an enamel lesion, root lesion, and sound root section which are characterized with polarized light microscopy and/or microradiography prior to insertion in the crown. After the experimental regimen, the sections are removed and re-characterized for any changes. The model has been used to evaluate mineral changes from the use of fluoride dentifrices and rinses, chewing gum, and food sequencing. The advantages of the model system are the before-and-after measurements on the same section, a natural plaque formation, interaction with saliva, episodic demineralization and remineralization, no bulky appliances, and the use of reasonable time frames. This model, therefore, reduces the artificiality of the in situ study to a great extent and appears to be a useful predictor of demineralization/remineralization interactions.

Adult↗
PubMed1992

Effect of fluoride concentrations on overdenture abutments.

This study evaluated the preventive effect of four concentrations of fluoride. Twenty-five extracted caries-free anterior teeth from patients aged 50-70 were prepared as overdenture abutments. The teeth were sectioned mesiodistally into two halves. The teeth were covered with a protective varnish, leaving a window on the root surface and one on the cut dentin of the occlusal. The root halves were randomly divided into 5 groups of 10 specimens and each group received a different 5-minute topical treatment prior to being placed in the demineralizing solution. The treatments were: Group 1: distilled H2O only; Group 2: 100 ppm F-, Group 3: 250 ppm F-, Group 4: 500 ppm F-; and Group 5: 1000 ppm F-. The teeth were cycled for 6 hours in a demineralizing solution and for 17 hours in a fluoride-free remineralizing solution. The cycling was maintained for 10 days. The root halves were sectioned and prepared for histologic examination. The depth of the lesions were measured from standardized photo-micrographs by means of a sonic digitizer. The conclusions were: (1) the lesions on the root surface were too small to be measurable, (2) the lesions on dentin were all of similar depth, and (3) the lesions had bands within them and the width of these bands showed a dose response to the fluoride concentration of the topical application.

Aged↗