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Biomedical subjects

B R Schemehorn

Publications and source records attributed to B R Schemehorn.

At least 19 recordsLinked to original sources
PubMed2002

A new fluoride-releasing rubber cup for professional oral hygiene.

Rubber cups in combination with prophylaxis pastes are commonly used for supragingival professional tooth cleaning. This procedure requires frequent interruption in order to collect fresh paste. Moreover, the paste-saliva slurry blurs the visibility, which implies intermittent rinsing to look for residual discolorations. Hawe Neos Dental (Bioggio, Switzerland) has developed a new prophylaxis cup aimed at cleaning and smoothing the tooth surfaces, while simultaneously fluoridating the enamel without a prophylaxis paste. This new prophylaxis cup was tested with respect to cleaning efficiency, resulting surface roughness, abrasivity, and the promotion of fluoride uptake into enamel. After 15 seconds of use, the new cup showed a cleaning efficiency which was 20 to 30% higher than that of a conventional rubber cup (p < 0.01) used with the prophylaxis pastes Nupro coarse or Hawe cleanic (78% vs. 57 and 49%). The fluoride cup had a smoothing effect on the enamel surface comparable to that effected by the two prophylaxis pastes. The abrasivity on enamel was lowest with the new cup. On dentin, abrasivity was comparable to Nupro coarse, but higher than with Hawe cleanic. The fluoride cup also produced a higher amount of KOH-soluble fluoride on the enamel surface when compared to Hawe cleanic. With respect to the structurally bound fluoride, no difference was found. The newly developed fluoride releasing Hawe Neos cup represents an effective alternative to conventional procedures for supragingival professional tooth cleaning on enamel.

Acidulated Phosphate Fluoride↗
PubMed2000

Stain removal efficacy of two new fluoride dentifrices containing essential oils.

PURPOSE: To assess in vitro the stain removal efficacy of two new antiplaque/antigingivitis dentifrices utilizing a modification of a previously validated Stookey method. MATERIALS AND METHODS: The modifications to the original Stookey method are the following: (1) study design; three 5 x 5 Latin Squares were employed to minimize bias stemming from position or test run in the study. (2) statistical success criteria; a test formulation was judged to be effective if the lower one-sided 95% confidence limit was "equal to or higher than" 50 since a minimum PCR (pellicle cleaning ratio) score of 50 is needed for a dentifrice to show clinical efficacy. The two test dentifrice formulations contained a fluoride source, a silica abrasive system, and four essential oils. The ADA reference abrasive material (calcium pyrophosphate) and placebo toothpaste were included as positive and negative controls, respectively. RESULTS: Compared to the negative control, the positive control exhibited a statistically higher PCR score; therefore, the validity of this modified Stookey method was confirmed. Additionally, the lower limits of the one-sided 95% confidence interval for the two dentifrice formulations were above the threshold PCR of 50; therefore, this modified Stookey method should predict that both essential oil-containing dentifrices possess acceptable stain removal power.

Analysis of Variance↗
PubMed1999

Laboratory enamel solubility reduction and fluoride uptake from enamelon dentifrice.

The presence of calcium-releasing ingredients in toothpastes containing sodium fluoride is usually avoided to prevent loss of active fluoride due to the formation of the insoluble calcium salt. The purpose of this study was to determine the bio-availability of fluoride from Enamelon Toothpaste (E), which simultaneously supplies fluoride, calcium and phosphate salts from a dual dispensing package. Fluoride uptake into artificially lesioned enamel cores due to the use of the test dentifrice (E) diluted 1:3 in whole human saliva was compared to that from a clinically proven effective sodium fluoride/silica USP reference toothpaste (C) and a non-fluoride control (E-w/o F). Enamel solubility reduction due to the use of E, C and E-w/o F was measured by determining the quantity of phosphate released to lactic acid buffer before and after treatment of the crowns of molars with 1:3 slurries of the dentifrices in water. Fluoride uptakes and enamel solubility reductions were 5031 +/- 158 ppm and 21.6 +/- 2.2% for E, 1915 +/- 39 ppm and 13.6 +/- 2.0% for C, and -3 +/- 2 ppm and 0.8 +/- 1.7% for E-w/o F. The fluoride uptake and enamel solubility reductions from E were significantly greater than from C (p < 0.001, Fisher LSD), and both fluoride-containing dentifrices significantly outperformed E-w/o F (p < 0.001). The laboratory results indicate that the calcium and phosphate salts delivered by the remineralizing Enamelon dentifrice increase the bioavailability of fluoride to substantially exceed that of the clinically proven standard dentifrice.

Analysis of Variance↗
PubMed1999

Remineralization by fluoride enhanced with calcium and phosphate ingredients.

The effectiveness of fluoride ions provided by toothpastes and mouthrinses in promoting remineralization can be limited by the low concentrations of calcium and phosphate ions in saliva. The purpose of this study was to determine whether improved remineralization can be obtained from toothpastes or mouthrinses that simultaneously deliver fluoride, calcium, and phosphate ions from dual-dispensing systems. Enamel specimens with artificial lesions between 60 and 90 microns deep were cycled 15 times through demineralization for 30 minutes, treated for 5 minutes with an experimental or control fluoride toothpaste or mouthrinse, and remineralized for 60 minutes. In the toothpaste study, surface hardness increased by 11.5 +/- 9.2 and 2.7 +/- 3.6 Vickers hardness units, and enamel fluoride content was 5984 +/- 521 ppm and 3971 +/- 531 ppm for the experimental and control fluoride toothpastes, respectively. Remineralization was confirmed by x-ray microradiography. In the mouthrinse study, surface hardness increased by 8.8 +/- 7.7 and 2.2 +/- 3.7 Vickers hardness units, and enamel fluoride content was 6111 +/- 1078 ppm and 3160 +/- 364 ppm for the experimental and control fluoride mouthrinses, respectively. Use of a non-fluoride control mouthrinse led to a decrease in surface hardness of 3.7 +/- 5.2 Vickers hardness units despite a fluoride content of 402 ppm. The results demonstrate that calcium and phosphate supplementation in a toothpaste or mouthrinse can improve remineralization and increase fluoride uptake.

Calcium Phosphates↗
PubMed1998

Laser fluorescence detection of demineralization in artificial occlusal fissures.

Laser fluorescence (LF) has been used previously to detect early smooth-surface lesions. Although its use for detection of occlusal demineralization has been implicated, it has not been demonstrated. The aim of this study was to determine whether LF could detect demineralization in the base of artificial fissures. To employ LF for detection of occlusal demineralization an apparatus was devised to direct laser light into fissures and simultaneously detect fluorescence from the base of the fissures. Three groups (n = 40/group) of differing fissure types were prepared (straight wall, converging and diverging wall) with either a sound or lesioned base. One half of each group was examined with LF and dye-enhanced LF (DELF); the other half was examined with LF, exposed to plaque, examined with LF and DELF, air-polished and examined with DELF. All images were scored twice as either (1) carious; (2) sound, or (3) undetermined, by a group of 3 examiners. For fissures without plaque, the average sensitivity was higher for DELF (0.76) than for LF (0.54) (p < 0.05). Likewise, the average specificity was higher for DELF (0.64) than for LF (0.29) (p < 0.05). In the presence of plaque, sensitivity was higher for DELF (0.91) compared to LF (0.43); however, specificity was lower for DELF (0.05) compared to LF (0.55). When the fissures were air-polished and then examined with DELF, sensitivity averaged 0.82 (p < 0.05), and specificity increased consistently (average 0.51, p < 0.05). It was concluded that, in the absence of plaque, DELF was a better diagnostic tool than LF for detection of demineralization in artificial fissures.

Animals↗
PubMed1997

Relative ability of laser fluorescence techniques to quantitate early mineral loss in vitro.

This in vitro investigation was undertaken to explore two different nondestructive methods to detect very early demineralization. These methods were based on the premise that the clinical detection of caries at a very early stage of formation might permit more efficient reversal of the caries process than may occur when lesions are detected at a more advanced stage, such as a so-called 'white spot'. The methods evaluated in this study were quantitative laser fluorescence (QLF) and an experimental dye-enhanced laser fluorescence (DELF) technique. Prepared and polished bovine enamel specimens were demineralized in a conventional lactic acid-Carbopol solution for varying periods of time between 0 and 24 h with an area of sound enamel retained on each specimen. The coded and randomized specimens were then analyzed for the presence and severity of enamel demineralization using QLF after which they were exposed to a selected dye (Pyrromethene 556) and similarly examined using DELF. The specimens were then sectioned and examined by conventional transverse microradiography and by confocal laser-scanning microscopy. Results were analyzed statistically with sensitivity and specificity determined using sound enamel as the reference. The results indicated that QLF could detect demineralization which occurred as a result of 8 h exposure to the decalcification solution and was able to quantify changes in lesion severity associated with longer demineralization. While DELF was capable of detecting enamel demineralization after only 2 h exposure to the decalcification solution, it was unable to quantify increasing amounts of demineralization associated with longer periods of exposure to the decalcification solution. In summary, while DELF was able to detect very early demineralization, only QLF was capable of detecting and quantifying changes in the extent of the decalcification occurring with demineralization periods up to 24 h.

Animals↗
PubMed1997

Effect of two fluorescent dyes on color of restorative materials.

PURPOSE: The objective of these two studies was to determine whether the use of dyes in vitro would affect the shade of tooth-colored restorative materials. MATERIALS AND METHODS: Two separate studies were performed. In Study 1, four groups (N = 36) of restorative materials; (1) resin composite (RSN), (2) resin-modified glass ionomer (RMGI), (3) conventional glass ionomer (CGI), and (4) porcelain (PCN), were subjected to a rinse in either tap water (control) or Pyrromethene 556 dye at a concentration of 0.01M for 30 seconds or 0.0015 M for 60 seconds. They were then rinsed with 25% ethanol as would be done in clinical usage. In Study 2, the same restorative materials (except PCN) were subjected to a rinse in either tap water (control) (N = 8) or 0.0018 M sodium fluorescein (N = 8) for 60 seconds followed by a 5-second rinse with tap water. For both studies the specimens were analyzed for overall color changes (delta E*) comparing baseline to immediately post dye exposure and then again after 1, 4, 24, and 48-hour storage under running tap water. In addition, an image of each specimen, illuminated under an argon laser light (HGM), was captured with a miniature charged-coupled device (CCD) color camera at the same time intervals when the color was measured. These images were analyzed for fluorescence using computer assisted methods. A software program then computed the mean and standard deviation of the fluorescence values for each image. The data were analyzed using repeated measures ANOVA. RESULTS: delta E* values from baseline on specimens treated with either Pyrromethene 556 or sodium fluorescein were not significantly different from water at any time. The only exceptions were CGI specimens exposed to 0.01 M Pyrromethene 556 and RMGI exposed to sodium fluorescein which had a higher delta E* immediately after treatment, however this effect was reversed after 1-hour rinse. Mean delta E* was less than 2.69 for specimens treated with Pyrromethene 556 and less than 3.20 for specimens treated with sodium fluorescein after 1-hour rinse in water. When the mean fluorescence level, as determined by the computer, was averaged there was no difference between the Pyrromethene 556 treatments and control for RMGI, RSN and PCN after 4-hour rinse in water and, as time in storage increased, the fluorescence level decreased. CGI treated with 0.01 M Pyrromethene 556 was significantly more fluorescent even after 48-hour rinse in water. All specimens treated with sodium fluorescein were also significantly more fluorescent than control even after 48-hour rinse in water. It was concluded that exposure of these restorative materials to Pyrromethene 556 at 0.01 M or 0.0015 M or to 0.0018 M sodium fluorescein will not lead to any prolonged visually detectable color changes.

Analysis of Variance↗
PubMed1996

The dentin abrasivity potential of a new electric toothbrush.

PURPOSE: To evaluate the safety of the new Braun Oral-B Ultra Plaque Remover (D9) electric toothbrush, by measuring its abrasivity to dentin and comparing it with the abrasivity of a standard ADA reference toothbrush. MATERIALS AND METHODS: Dentin abrasion was measured by a radiotracer technique, using a modification of the ADA recommended methodology. A V-8 cross-brushing machine, set to make 1,500 strokes, was used for the standard reference ADA toothbrush. Because the electric toothbrush would not fit on the V-8 machine, the brushing procedure was modified so the D9 was suspended from a ring stand in a shaker bath set to give 44 strokes/minute. Both toothbrushes were tested with a slurry of 25 g of Crest dentifrice in 40 ml of water. After both toothbrushes had been tested for 8.5 minutes, samples of the slurry were put in a scintillation counter and mean net counts per minute (cpm) per gram of slurry were calculated. RESULTS: The mean relative dentin abrasion (RDA) of the Braun Oral-B Ultra Plaque Remover (D9) brush was found to be low (16) and was markedly less than that of the ADA reference brush (100).

Dental Plaque↗
PubMed1996

A laboratory investigation of stain removal from enamel surface: comparative efficacy of three electric toothbrushes.

PURPOSE: To evaluate in a controlled laboratory investigation the efficacy of three electric toothbrushes with respect to removal of extrinsic dental stain from labial enamel surfaces of bovine permanent central incisors. MATERIALS AND METHODS: Enamel specimens were treated to produce a uniformly stained pellicle film. Staining was assessed photometrically, before and after brushing 16 specimens per group for 4.5 minutes with either the Braun Oral-B Plaque Remover (D7), the Braun Oral-B Ultra Plaque Remover (D9) or a high frequency electric toothbrush. A manual brush with the ADA reference abrasive was used as a positive control, and this was compared with the three electric toothbrushes, using a dentifrice slurry prepared from Crest toothpaste. Tension on the enamel specimens was set at 150 g, except for the high frequency toothbrush which was set at the manufacturer's recommended tension of 50 g. Stain removal was expressed as a cleaning ratio (CR), where larger values represented greater removal of stained pellicle. RESULTS: Compared with the ADA control (CR = 100), the D9 was the most effective (CR = 98) removing significantly more stain (P < 0.05) than the D7 (CR = 74). The high frequency toothbrush was found to be the least effective (CR = 48), removing significantly less stain than any of the other toothbrushes (P < 0.05).

Analysis of Variance↗
PubMed1996

Hard tissue abrasivity of an automatic interdental plaque remover.

This laboratory study was conducted to assess the safety of a new interdental cleaner, the Braun Oral-B Interclean (ID2), by measuring its abrasivity to dentin and comparing this with the abrasivity of a standard ADA manual toothbrush when used with and without dentifrice. Dentin abrasion was measured by a radioactive technique, using a modified ADA-recommended methodology. Dentin specimens to be used with the ID2 had a 2 mm hole drilled through them to represent the interproximal space, whereas dentin slabs were used in the toothbrush abrasivity tests. All specimens were placed in a controlled neutron flux. The dentin specimens were then immersed either in an abrasive dentifrice (Crest) slurry or a non-abrasive (water) solution, and an 8.5 minute treatment carried out. After testing, samples of treatment slurry or solution were put in a scintillation counter and mean net counts per minute (cpm) per gram of slurry or solution were calculated. With Crest dentifrice, the ID2 removed significantly less (p < or = 0.05) dentin (232 cpm/g) than the ADA reference manual toothbrush (789 cpm/g). Without dentifrice, neither the ID2 nor the manual toothbrush removed significant amounts of dentin, and dentin loss was similar for both devices.

Analysis of Variance↗
PubMed1995

Acidogenicity of high-intensity sweeteners and polyols.

PURPOSE: To evaluate the plaque pH responses to sucrose, fructose, xylitol, sorbitol, acesulfame-K, aspartame, and saccharin at equal sweetness levels (equivalent to 10% sucrose) and water using an indwelling plaque pH telemetry system. MATERIALS AND METHODS: Eight adult panelists used each sweetener once in a Latin square study design. Plaque was allowed to accumulate for 3-6 days before each challenge period, and the panelists fasted for 12 hours prior to the 2-minute test rinse. Plaque pH was monitored for a 2-hour period after the rinse exposure. The parameters examined were area of the curves under pH 5.5 (pH X Time), pH changes from baseline, lowest pH attained and time below pH 5.5. RESULTS: The the high-intensity sweeteners (aspartame, saccharin and acesulfame-K) and the polyols (sorbitol and xylitol) were all non-acidogenic and were not significantly different from each other while both sucrose and fructose were highly acidogenic.

Adult↗
PubMed1995

The effect of an oscillating/rotating electric toothbrush and a sonic toothbrush on removal of stain from enamel surfaces.

This laboratory investigation compared the Sonicare toothbrush, the Braun Oral-B Plaque Remover and a manual brush, in terms of removal of stained pellicle from the surface of enamel specimens. Enamel specimens were stained over a period of 4 days to produce a stained pellicle film. Staining was assessed photometrically before and after brushing 16 specimens per group for 4.5 minutes with the three test toothbrushes and dentifrice slurry prepared from Crest toothpaste. The positive control consisted of the ADA reference abrasive and a manual toothbrush. Results were expressed as a cleaning ratio (CR), with higher values representing more efficient stain removal. Analysis of results revealed that removal of stain from the enamel surfaces was similar in the Braun Oral-B Plaque Remover group (CR 94) and the reference standard group (CR 100). There was no statistically significant difference between these 2 groups. In contrast, stain removal in the Sonicare toothbrush group and the manual toothbrush group was significantly less effective (p<0.01), with a mean CR of 66 and 76, respectively. There was no statistical difference between the cleaning ratio scores for these 2 groups. It is concluded that extrinsic stain removal with the Sonicare toothbrush is similar to that achieved with a manual brush, but that stain removal with the Braun Oral-B Plaque Remover is significantly more effective.

Analysis of Variance↗
PubMed1991

Use of an in vitro model to assess the effects of APF gel treatment on the staining potential of dental porcelain.

Porcelains and resin composites exposed to acidulated phosphate fluorides (APF) have been reported to result in increased roughness, loss of weight, and loss of specular reflectance (gloss). Six samples of five commercial porcelains were subjected to five four-minute treatments with APF gels. Samples were then subjected to a nine-day cyclic staining procedure that utilized a tea, coffee, and mucin mixture. Changes in reflectance were then measured by means of a Minolta Chromameter (CR121) and converted to CIE L* a* b* values at illuminant D65 against a white background. delta L*, delta a*, delta b*, and delta E values were calculated. There was a substantial decrease in the L* value (lightness) for all porcelains. The average L* value for APF-treated and then stained porcelains was 43.6, for the stained-untreated samples, 48.2, and for untreated-unstained porcelain, 53.5. For three of the five porcelains, the differences in L* between treated and untreated stained porcelains were statistically significant. Changes in a* and b* values were also found to be consistent with but not as large as the changes in L*.

Acidulated Phosphate Fluoride↗
PubMed1990

Effect of sorbitol gum chewing on plaque pH response after ingesting snacks containing predominantly sucrose or starch.

The purpose of this study was to determine the effect of chewing a sorbitol gum (Trident) for 10 minutes on interproximal plaque pH changes following ingestion of selected sucrose- or starch-containing foods. The snacks containing predominantly sucrose (and/or simple sugars) were chocolate bar, cream-filled cupcakes, cream-filled sandwich cookie, cherry pie and raisins. The snacks containing predominantly starch were oat cereal, granola bars, pretzels, potato chips and corn chips. Plaque pH responses were monitored using an indwelling wire-telemetry system in five adult panelists. The test design involved two sets of 5 x 5 Latin square randomization in which each set consisted of two series of tests. In the first series of tests, the fasted, resting plaque pH was recorded for 5 minutes, panelists ingested the designated snacks for 2 minutes, and the pH response was monitored for the remainder of a 2-hour period. In the second series of tests, the same procedure was followed through the snack ingestion. After the pH response to the snack was monitored for 15 minutes, the panelists were asked to chew one stick of sorbitol gum for 10 minutes and the pH response was then monitored for the balance of the 2-hour period. Results indicated that both the sugar- and starch-containing snacks tested in this study caused significant decreases in interproximal plaque pH. Chewing a sorbitol gum after ingestion of the snacks significantly reduced the demineralizing potential of the plaque. The chewing of sorbitol gum following the ingestion of snacks can be recommended as an adjunct to other caries-preventive oral hygiene measures.

Chewing Gum↗
PubMed1990

The impact of chewing sugarless gum on the acidogenicity of fast-food meals.

The objective of this study was to evaluate the effect of chewing sorbitol gum on plaque pH following the ingestion of acidogenic fast-food meals. Plaque pH response was monitored using an indwelling wire-telemetry system in five adult panelists. From a pilot study with 12 fast-food meals, the most acidogenic breakfast, lunch and dinner were selected for this study. In the first test, the fasted, resting plaque pH was recorded for 5 minutes; panelists ingested the selected meals for 10 minutes, rinsed thoroughly with 50 ml of tap water, and the pH response was monitored for the remainder of a 2-hour period. In the second test series, the same procedures were followed through the post-meal ingestion rinse. After the pH response to the meal was monitored for 5 minutes, the panelists chewed a sorbitol gum for 15 minutes in their usual manner and the panelists were encouraged to move the gum around their mouth, however, it appeared as if they favored the side of their mouth without the partial denture. The pH response was monitored for the balance of the 2-hour period. All panelists ate the test foods, with and without the chewing gum, according to a randomized-block test design. The results indicated that the use of sorbitol gum significantly raised the plaque pH, prevented the subsequent pH drops after the fast-food meal ingestion and reduced the pH curve area under 5.5.

Chewing Gum↗