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PubMedDate not supplied

Digital subtraction radiography for monitoring dental demineralization. An in vitro study.

The aim of the present study was to evaluate the assessment of progression of demineralization by digital subtraction radiography. In each of 14 extracted human teeth, 2 approximal enamel demineralization lesions were induced in vitro to simulate dental caries. A modified tunnel preparation with glass ionomer fillings was performed on one lesion of every tooth as a model of caries inhibition. Every week, radiographs were obtained under standardized conditions over a period of 42 days. The radiographs were digitized and calibrated for grayscales. Reference landmarks were chosen and aligned for the different pictures by computer-assisted imaging to adjust the images for projective distortions. The images of the 7th, 14th, 21st, 28th, 35th and 42nd day were subtracted from the baseline radiograph. The mean value of gray values of the subtraction images was calculated and ANOVA tests for repeated measurements and paired t tests were used for statistical analysis. The results of the present study indicate that statistically significant gray level changes due to progression of demineralization could be detected in the radiographic images by subtraction analysis. Differences between glass ionomer-filled and nonfilled lesions failed to reach significance. The introduced method may have the potential to detect and document minute caries progression.

Analysis of Variance↗

PubMed2000

Optical scattering power for characterization of mineral loss.

Mineral loss in early caries cannot be measured without invasive procedures. To quantify mineral loss without sectioning the tooth, one must determine the optical scattering of the enamel. Using enamel white-spot lesions, we hypothesize that the optical scattering power (Sp) of the demineralized enamel would provide a quantitative estimate of mineral loss. Enamel slabs were demineralized to produce artificial white spots. The data were acquired by means of a Charge-Coupled Device (CCD) camera and image-processing software. For the purpose of comparison, mineral loss (deltaZ) of the demineralized samples was determined by the use of a microhardness approach after the samples were sectioned. The scattering power correlated well with deltaZ (r2 = 0.82). In contrast, simple reflectance of the demineralized samples correlated poorly with deltaZ (r2 = 0.22). The validity of using scattering power to measure demineralization has been confirmed by a three-dimensional Monte Carlo Simulation.

Animals↗

PubMed2005

First-choice treatment alternatives for caries removal using the chemomechanical method.

Modern dentistry aims to preserve tooth structure using minimally invasive procedures. Chemomechanical removal of caries is a new method with the advantage of selective removal of severely demineralized dentin. In addition, the method enhances the clinician's ability to diagnose caries. Ensuring chairside caries diagnosis and removal, based on biologic principle, helps to preserve as much healthy tissue as possible. However, while this method is most comfortable for the patient, treatment time is prolonged. In most cases, the method has to be used in combination with a conventional bur. Also, caries lesions in which removal of enamel or a restoration is needed cannot be treated exclusively using the chemomechanical method. This article describes the mechanism of action of the chemomechanical method (CarisolvTM) for caries removal. Indications for use of the chemomechanical method as a first-choice treatment are presented. Clinical cases in which this new approach provides a significant clinical advantage are also described.

Adolescent↗

PubMed1986

Ultrastructure of the dental epithelium during enameloid mineralization in a teleost fish, Cichlasoma cyanoguttatum.

Secretory-stage inner dental epithelial cells (IDE) of tooth buds deposited an unmineralized, ectodermally-derived, enameloid collagen matrix. Pharyngeal plates bearing tooth buds were fixed: some were demineralized, others treated with guanidine-EDTA, then fixed and post-fixed in osmium tetroxide with potassium ferricyanide. Thin Epon sections were viewed in a Jeol 100B TEM. Nascent enameloid crystals were orientated parallel to the collagen fibres and attained widths of 200 nm. Enameloid collagen was absent in demineralized mature enameloid. The outer dental epithelial plasma membrane was deeply invaginated forming extensive channels associated with elongated fuzzy-coated vesicles. Four configurations of IDE cells were characterized by cellular constituents, including elongated granules, Golgi complexes, multivesicular bodies, large electron-dense granules and extracellular amorphous material which was also adjacent to cells containing few organelles associated with protein synthesis, within infoldings of ruffled apical membranes and multivesicular bodies. This material was considered to be resorbed enameloid collagen, not a secretory product.

Amelogenesis↗

PubMed2001

Use of optical coherence tomography for assessment of dental caries: quantitative procedure.

A method for quantitative assessment of dental caries using optical coherence tomography (OCT) was demonstrated. Development of caries lesions in 15 bovine teeth, by demineralization in acidic buffer solution, was quantitatively assessed daily for 3 days, using OCT. An OCT system which can collect A-scans (depth versus reflectivity curve), B-scans (longitudinal images) and C-scans (transverse images at constant depth) was used. While the B- and C-scans qualitatively described the lesion detected, the A-scan which showed the depth (mm) resolved reflectivity (dB) of the tooth tissue was used for the quantitative analysis. After a simple normalization procedure to determine the actual depth the light travelled into the tooth tissue, the area (R) under the A-scan was quantified as a measure of the degree of reflectivity of the tissue. The result showed that R (dB mm) decreased with increasing demineralization time. The percentage reflectivity loss (R%) in demineralized tissue, which related to the amount of mineral loss, was also calculated, and it was observed that R% increased with increasing demineralization time. It was concluded that with the above procedure, OCT could quantitatively monitor the mineral changes in a caries lesion on a longitudinal basis.

Animals↗

PubMed2006

Thirty-five percent carbamide peroxide application causes in vitro demineralization of enamel.

OBJECTIVES: The objective of this in vitro study was to investigate whether a high concentration 'in-office' bleaching agent affected the mineral content of enamel and dentin. METHODS: A commercially available 35% carbamide peroxide bleaching agent was applied for 2h to sectioned teeth (n=11). Specimens were then immersed in artificial saliva at 37 degrees C for a further 24h to simulate the oral environment. Tomographic images of these sections were obtained (micro-CT 80, Scanco, Switzerland) prior to and post-bleach application. Eight three-dimensional regions of interest (ROI), starting from the enamel surface extending to the dentinoenamel junction, were selected for each section. The hydroxyapatite equivalent mineral concentrations (g/cm(3)) of the ROIs were calculated. Any changes in mineral content as a consequence of the bleaching procedure were calculated in relation to each ROI. RESULTS: There was a significant reduction in the mineral content of enamel specimens post-bleach application extending to a depth of 250microm (paired t-test, p<0.05); this reduction in mineral content was greatest in the ROI's closest to the tooth surface. There was, however, no significant difference in the mineral content of dentin as a consequence of bleaching. SIGNIFICANCE: This in vitro study has shown that significant demineralization of enamel occurred following bleaching with 35% carbamide peroxide. The concept that 'in-office' bleaching is a non-destructive cosmetic procedure should be reconsidered.

Carbamide Peroxide↗

PubMed1990

Dependence of in vitro demineralization of apatite and remineralization of dental enamel on fluoride concentration.

The anti-caries activity of fluoride is contributed to in several ways. Two major aspects of fluoride action are (i) the inhibition of demineralization at the crystal surfaces within the tooth, and (ii) the enhancement of subsurface remineralization resulting in arrestment or reversal of caries lesions. Fluoride present in the aqueous phase at the apatite crystal surface may play a determining role in the inhibition of enamel or dentin demineralization. In one part of the present study, the initial dissolution rate of synthetic carbonated-apatite in acetate buffers was measured with fluoride present in the buffer in the 0-2.6 mmol/L (0-50 ppm) range. Inhibition of demineralization was shown to be a logarithmic function of the fluoride concentration in solution. In the second part of the present study, an in vitro pH-cycling model was used for determination of the effect on net de/remineralization of enamel by treatment solutions containing fluoride in the 0-26 mmol/L (0-500 ppm) range. The net mineral loss was shown to be negatively related to the logarithm of the fluoride concentration. These studies have demonstrated an exponential quantitative relationship between fluoride concentration and inhibition of apatite demineralization or enhancement of remineralization. The clinical implications are (i) that simply increasing fluoride concentration may not necessarily give increased cariostatic benefit, and (ii) that improving the means of delivery of relatively low fluoride concentrations for longer times should be more appropriate for enhancing clinical efficacy.

Apatites↗

PubMed2005

Blood cell attachment to root surfaces treated with EDTA gel.

Root debridement generates a smear layer which contains microorganisms and toxins that could interfere in periodontal healing. For this reason, different substances have been used to remove it and to expose collagen fibers at the tooth surface. Blood element adhesion to demineralized roots and clot stabilization by collagen fibers are extremely important for the success of periodontal surgery. The aim of this study was to evaluate the different patterns of blood element adsorption and adhesion to root surfaces only irrigated with distilled water and after application of a manipulated or an industrialized EDTA gel. Thirty samples were planed, equally divided into three groups and treated with distilled water (control), a manipulated EDTA gel or an industrialized one. Immediately after, samples were exposed to fresh blood and prepared for scanning electron microscopy. Untreated planed dentin presented the best results with blood cells entrapped in a thick web of fibrin. In the manipulated EDTA group, the web of fibrin was thick with sparse blood elements. The worst result was seen with the industrialized EDTA group, in which no blood elements could be seen. Statistical difference was obtained between control and industrialized EDTA groups. Surfaces only irrigated presented the most organized fibrin network and cell entrapment.

Adsorption↗

PubMed1993

Dentin pretreatment and caries inhibition by a fluoride-releasing resin.

The purpose of this study was to examine the effect that phosphoric acid etchant, used to remove the smear layer, may have on dentin demineralization inhibition. Fifteen molars had Class V preparations placed on the mesial and distal surfaces, the gingival seat being placed 1 mm below the cementoenamel junction. Randomly, one preparation of each tooth had etchant placed carefully on only enamel for 30 seconds. Etchant was placed on the gingival seat dentin of the remaining preparations, as well as the enamel for 30 seconds. A HEMA dentin primer containing maleic acid was placed and allowed to dry on the unetched dentin, then a Bis-GMA resin with tetrabutyl ammonium tetrafluoroborate was placed. Only the fluoridated resin was placed over the dentin that had been etched. All teeth were then restored with resin composite and subjected to an artificial caries challenge (pH 4.4) for 7 days. Sections 100 microns were obtained, photographed under polarized light microscopy and demineralized areas were digitized. Results demonstrated the mean area (mm2 +/- S.D.) demineralization 0.5 mm from the gingival margin to be: etched dentin (0.77 +/- 0.36); non-etched dentin (1.52 +/- 0.98). A t-test indicated that there was significantly less demineralization when the fluoridated resin came in direct contact with dentin that had the smear layer removed (P < 0.05).

Acid Etching, Dental↗

PubMed2006

Remineralization potential of a fluoridated carbamide peroxide whitening gel.

PURPOSE: Little knowledge exists regarding the potential remineralizing benefits of adding fluoride to carbamide peroxide-based whitening gels. The aim of this project was to evaluate whether a whitening system with fluoride will remineralize previously demineralized enamel. MATERIALS AND METHODS: Twenty-four extracted teeth were sectioned into quadrants labeled A to D. Tooth quadrants in groups A, B, and D were demineralized with a lactic acid, methyl-cellulose gel system to mimic incipient carious lesions. Group C was neither demineralized nor treated. Group D was demineralized, but not treated with a whitening gel. Groups A and B were exposed to one of two commercially prepared 10% carbamide peroxide whitening gels: one that was fluoride free (group A) and one that contained fluoride (0.463%NaF) (group B). Remineralization was evaluated histologically and analyzed statistically using paired t tests accepting p < 0.05 as significant. RESULTS: Shade comparisons showed equal whitening efficacy of both gel A and B. Paired t tests show a significant reduction in lesion depth after treatment with the fluoride containing gel (B: mean lesion depth = 100 microm; p < 0.01), while there was no difference for the gel lacking fluoride (A: mean lesion depth = 110 microm). CONCLUSION: Under the conditions of this study, the addition of fluoride to a tooth whitening system does not affect the gel's whitening efficacy. The addition of fluoride could provide remineralization properties to the gel. As tooth whitening therapies continue to grow and evolve, a strong focus should rest on improving these materials in ways that will provide ever greater patient benefits. Coupling the esthetic benefits of whitening with the preventive benefits of fluoride is a natural step in this direction. CLINICAL SIGNIFICANCE: Therapuetic quantities of fluoride can impact remineralization properties of commercially available tooth whitening gels without altering whitening properties.

Carbamide Peroxide↗

PubMed1999

Fluoride release from restorative materials and its effects on dentin demineralization.

As the use of adhesive restorative materials has increased during the last several years, interest in adhesive materials that release fluoride has also grown. The purpose of this study was to measure fluoride release from several adhesive restorative materials and to evaluate its effect on dentin resistance to demineralization and on bacterial metabolism in a modified in vitro system. Standardized cavities (1.8 mm in diameter) were prepared in bovine teeth that had been ground to dentin. One cavity in each tooth was restored with one of the following restorative systems: (a) Single Bond and Z100; (b) Single Bond and Tetric Ceram; (c) Fuji Bond LC and Z100; (d) Fuji Bond LC and Tetric Ceram; (e) Fuji II LC; or (f) Fuji IX GP. The other cavity in each tooth was "restored" with wax as a control. For each restorative system, 12 specimens were evaluated for fluoride release during the first 24 hrs after restoration placement. Dentin adjacent to the restored sites was subjected to lactic acid challenge (pH 4.3) for 3 hrs, after which calcium release was measured. Another 12 specimens in each group were stored for 24 hrs in de-ionized water, and were exposed to an S. mutans suspension (1:1 THB/de-ionized water and 50 mM glucose, A660 = 0.2) for 6 hrs, followed by calcium release and pH measurement. Bulk specimens of each material were also made and stored in water. Fluoride released from Fuji Bond LC, Fuji IX GP, and Fuji II LC in bulk was significantly greater than from the other materials. In the restored dentin specimens, increased resistance to demineralization from a lactic acid challenge was directly related to fluoride release. The same effects were seen as a result of the S. mutans challenge. While fluoride release from restorative materials increased the resistance of dentin to demineralization in this system, the clinical relevance of the findings is not known.

Animals↗

PubMed1990

The use of 'Fluor Protector', a fluoride varnish, as a caries prevention method under orthodontic molar bands.

The aim of this study was to determine whether Fluor Protector, a fluoride varnish, applied to molars before orthodontic banding could prevent white spot formation. In the in vitro study 93 human premolars were used, divided in five different groups, representing different clinical situations. Each tooth was sliced in half, one as a control and the other as a test specimen. All tooth halves were stored in a demineralizing solution, in an attempt to induce white spot formation. In the in vivo study 104 molars (52 controls and 52 tests) of 28 orthodontic patients were involved. The 'split-mouth technique' was used. After evaluation of the results of both studies, it is evident that Fluor Protector is very effective in the prevention of white spot formation under molar bands.

Dental Caries↗

PubMed1997

Identification of calprotectin, a calcium binding leukocyte protein, in human dental calculus matrix.

Calprotectin is a calcium binding protein produced by leukocytes, macrophages and epithelial cells, and its levels in several tissues increase during infections and in many inflamed areas, suggesting that it may be an indicator of inflammatory activity. Osteopontin is a prominent phosphorylated glycoprotein in bone matrix, having calcium binding capacity. Recently, it has been reported that calprotectin and osteopontin are present in urinary stones (pathological mineralized masses in the body), and that these proteins may be involved in their formation. Dental calculus formed by mineralization of dental plaque is an inflammatory factor which may contribute to periodontal disease. It contains many organic components involved in mineralization. We recently found osteopontin molecules in human dental calculus and suggested that the components of its matrix may be similar to those of urinary stones. In this study, we investigated the presence of calprotectin in human dental calculus by immunohistochemical and immunoblotting analyses using a specific antibody for calprotectin. After fixation and demineralization of dental calculi adhered to tooth roots, sections embedded in paraffin were immunoreacted with the antibody for calprotectin and positive immunostaining for calprotectin was observed. Dental calculus proteins were then extracted with EDTA and separated by electrophoresis on 15% polyacrylamide gels. By immunoblotting analysis, 3 or 4 bands were observed at 11, 14.5, 22-25, 28 or 36.5 kDa and these patterns corresponded to those of calprotectin subunits. When non-immune rabbit serum was used instead of calprotectin-specific antibody as a negative control, no immunoreactivity was observed. These findings indicate that calprotectin is associated not only with antibacterial action but also with calcium binding capacity during dental calculus formation.

Calcium-Binding Proteins↗

PubMed1998

Effect of topical fluoride application before and after amalgam restoration placement on recurrent caries inhibition.

PURPOSE: To evaluate the in vitro caries inhibition effects of 1.23% APF foam topical fluoride treatment of cavity preparations, prior to restoration placement and after restoration placement. MATERIALS AND METHODS: Sixty standardized Class V preparations were placed in molars. Randomly, 40 teeth received an amalgam restoration: Twenty other teeth had 1cc 1.23% APF foam applied to preparation surfaces for 1 minute, then an amalgam restoration was placed. The APF was not rinsed away prior to restoration, it was displaced by the pressure of the amalgam being condensed into the preparation. Twenty of the initial 40 amalgam restorations had 1 cc 1.23% APF foam applied to the external tooth/restoration margins for 4 minutes, the remaining 20 amalgam restorations acted as the controls. Acid-resistant varnish was placed, leaving 1 mm of tooth adjacent to restoration margins exposed. All specimens were subjected to an artificial caries challenge (pH 4.4) for 5 days. Sections of 100 microns were cut longitudinally through the restored margins, photographed under polarized light microscopy, then demineralized areas adjacent to restoration margins were quantitated. RESULTS: Results demonstrated the mean (+/- S.D.) area (microns 2) of demineralization 100 microns from the restoration margins to be: amalgam 10,221 +/- 524, amalgam with 1-minute APF over preparation 529 +/- 557, amalgam with 4-minute APF over external surface 736 +/- 359. ANOVA and Duncan's (P < 0.05) indicated both 1.23% APF foam topical fluoride treatment regimens exhibited significantly less demineralization at restoration margins than the non-treated amalgam control. There was no significant difference between the two fluoride placement regimens examined in this study.

Acidulated Phosphate Fluoride↗

PubMed2002

Safety profile of a new liquid whitening gel.

Colgate Simply White Clear Whitening Gel, an at-home tooth-whitening product purchased over the counter, contains 18% carbamide peroxide (equivalent to 6.5% hydrogen peroxide) as the active ingredient in a brush-applied liquid gel. The excipients include ingredients commonly used in dentifrices. The potential for effects on the tooth pulp, oral soft tissue irritation, enamel damage, and tooth sensitivity with this peroxide-containing product have been evaluated. An in vitro study demonstrated that pulpal chamber hydrogen peroxide levels are well below those considered to cause an effect on pulpal tissue. An exaggerated-use (4 applications per day for 3 weeks) clinical study showed that no oral irritation occurred during 3 weeks of use. A study measuring peroxide salivary concentration after use of Colgate Simply White Clear Whitening Gel showed that the concentration of peroxide in the saliva after use of the product was extremely low, further supporting the position that this product has a low potential for causing oral irritation. Additional studies demonstrate that Colgate Simply White Clear Whitening Gel does not harm the enamel surface or produce demineralization after exposure equivalent to 3 weeks of normal use and over 6 weeks of exaggerated use. Colgate Simply White Clear Whitening Gel has not produced oral irritation (hard and soft tissues) or tooth hypersensitivity in a clinical subject population of 141 individuals using varying treatment regimens. These studies prove that Colgate Simply White Clear Whitening Gel is safe for daily use as directed.

Bicuspid↗

PubMed2003

In vivo inhibition of demineralization around orthodontic brackets.

Demineralization around orthodontic appliances is a problem. Suboptimal oral hygiene, long intervals between appointments, and potentially poor patient cooperation with using fluoride dentifrices and mouth rinses necessitate a compliance-free means of preventing tooth decay. The hypothesis of this study was that fluoride released by glass ionomer cement inhibits the formation of carious lesions around orthodontic brackets in vivo. Brackets were bonded on 2 first premolars in 21 randomized, consecutively selected patients 11 to 18 years old. Eleven test-group subjects were bonded with fluoride-releasing glass ionomer cement, and 10 control subjects were bonded with composite resin (no fluoride). The teeth were extracted after 4 weeks, sectioned, and evaluated quantitatively by cross-sectional microhardness testing. Fluoride levels in patient saliva were measured by the Taves diffusion method in samples taken at days 0 (baseline), 1, 2, 3, 7, 14, 21, and 28 to determine whether fluoride from the glass ionomer cement influenced the overall intraoral fluoride levels. The results demonstrated significantly more demineralization around the brackets of the control patients (P <.01, Wilcoxon signed rank test). For whole-mouth salivary fluoride levels, no significant overall difference between the groups (P >.05) and no noticeable trend within groups (P >.05) were found. These results indicate that using fluoride-releasing glass ionomer cement for bonding orthodontic brackets successfully inhibited caries in vivo. This cariostatic effect was localized to the area around the brackets and was statistically significant after 4 weeks.

Acrylic Resins↗

PubMed1996

Orthodontic tooth movement following guided tissue regeneration: report of three cases.

This report presents three patients with advanced adult periodontitis and in which orthodontic tooth movement was performed subsequent to guided tissue regeneration procedures. Clinical follow-up showed a mean 3.3-mm attachment gain in the deepest preoperative probing depth sites, and radiographs revealed bone fill following guided tissue regeneration procedures with resorbable and nonresorbable membranes, with and without the use of demineralized freeze-dried bone allograft. Orthodontic tooth movement into the regenerated areas was successful. The feasibility of orthodontic tooth movement following successful regenerative procedures is discussed.

Adult↗

PubMedDate not supplied

In vivo dental plaque pH variation with regular and diet soft drinks.

PURPOSE: Despite the presence or absence of artificial sweeteners in cola drinks, both regular and diet soft drinks still contain phosphoric and citric acid, which contributes to the total acidic challenge potential on enamel. The purpose of this study was to assess the plaque pH, in vivo, after a substrate challenge of diet and regular soft drinks. METHODS: Seventeen subjects were recruited for this study. All subjects were between the ages of 12 and 15 and had at least 4 restored tooth surfaces present. The subjects were given consent by their parents and were asked to refrain from brushing for 48 hours prior to the study. At baseline, plaque pH was measured from 4 separate locations using touch electrode methodology. Each subject was then randomly assigned to one of two groups. The first group was exposed to regular Coke followed by Diet Coke, while the second group was exposed to Diet Coke followed by regular Coke. Subjects were asked to swish with 15 ml of the respective soft drink for one minute. Plaque pH was measured at the 4 designated tooth sites at 5-, 10- and 20-minute intervals. Subjects then repeated the experiment using the other soft drink. RESULTS: The results showed that regular Coke had significantly more acidic plaque pH values at the 5-, 10- and 20-minute intervals compared to Diet Coke, (P = < .001), when subjected to a t test. The mean pH at 5 minutes for Coke and Diet Coke was 5.5 +/- 0.5 and 6.0 +/- 0.7, respectively. At 10 minutes, the pH for Coke and Diet Coke was 5.6 +/- 0.6 and 6.2 +/- 0.7, respectively. The pH at 20 minutes for Coke and Diet Coke was 5.7 +/- 0.7 and 6.5 +/- 0.5, respectively. CONCLUSIONS: These data suggest that regular Coke possesses a greater acid challenge potential on enamel than Diet Coke. However, in this clinical trial, the pH associated with either soft drink did not reach the critical pH which is expected for enamel demineralization and dissolution.

Adolescent↗