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Results for “Tooth Demineralization”

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PubMed2005

Early caries imaging and monitoring with near-infrared light.

Enamel is highly transparent in the near infrared (NIR); therefore, this region of the electromagnetic spectrum is suited ideally for the development of new optical diagnostic tools for the detection and imaging of early dental caries. This article discusses the NIR optical properties of sound and demineralized dental enamel and the potential use of polarization sensitive optical coherence tomography and NIR transillumination for the imaging of dental caries.

Dental Caries↗

PubMed2007

Electric device improves bonds of simplified etch-and-rinse adhesives.

OBJECTIVES: This study investigated the effects of an electric field produced by a new device for the application of etch-and-rinse adhesives on demineralized dentin surfaces. METHODS: Three simplified etch-and-rinse adhesives (Single Bond, Prime&Bond NT and One-Step) were applied with the electric device and compared with controls prepared with disposable sponges. Specimens were processed for microtensile bond strength test and nanoleakage investigation using high resolution SEM. RESULTS: Microtensile testing revealed higher bond strengths (p<0.05) for all adhesives tested when electricity was used. Adhesive interfaces prepared with electric impulses exhibited very homogenous hybrid layers with minimal nanoleakage compared with the controls. SIGNIFICANCE: The use of electricity produced by a new electronic device during the application of dentin adhesives may increase adhesive adaptation to the dentin substrate and improve dentin hybridization due to the substrate modifications induced by an electric field on the demineralized dentin organic matrix.

Bisphenol A-Glycidyl Methacrylate↗

PubMed2006

The effect of copper on demineralization of dental enamel.

Previous studies have concluded that copper might inhibit enamel demineralization in vitro. Our aim was to assess the effect of copper (Cu2+), with and without amine fluoride, on human dental enamel under cariogenic challenge in situ. In a double-blind randomized four-leg crossover trial, 14 individuals wore a removable appliance containing 2 enamel slabs, 1 containing an artificial caries lesion. During each leg, the appliance was exposed twice daily to one of the test solutions: 1.25 mM CuSO4, amine fluoride (250 ppm F), copper and amine fluoride combined, or a placebo (water). A cariogenic challenge was provided in all cases by 5 daily exposures to 10% sucrose. Slabs were assessed before and after 21 days' exposure by Knoop microhardness and transverse microradiography. Significantly less demineralization was observed with Cu2+ and fluoride in combination than with fluoride treatment alone (p < 0.05), whereas copper alone had no significant protective effect.

Adult↗

PubMed2000

Fluoride pit and fissure sealants: a review.

There are two methods of fluoride incorporation into fissure sealants. In the first method, fluoride is added to the unpolymerized resin in the form of a soluble fluoride salt that releases fluoride ions by dissolution, following sealant application. In the second method, an organic fluoride compound is chemically bound to the resin and the fluoride is released by exchange with other ions (anion exchange system). This report reviews the literature on the effectiveness of all the fluoride-releasing sealants--commercial and experimental--that have been prepared using either the former or the latter method of fluoride incorporation. There is evidence for equal retention rates to conventional sealants and for ex vivo fluoride release and reduced enamel demineralization. However, further research is necessary to ensure the clinical longevity of fluoride sealant retention and to establish the objective of greater caries inhibition through the fluoride released in saliva and enamel.

Cariostatic Agents↗

PubMed2002

Effect of fluoride application on tensile bond strength of self-etching adhesive systems to demineralized dentin.

STATEMENT OF PROBLEM: It has been reported that the bond strength of composite to demineralized dentin is lower than that to sound dentin. This can be a problem in the success of so-called sealed restorations. PURPOSE: The aim of this study was to evaluate the effect of fluoride application on the tensile bond strength of self-etching adhesive systems to demineralized dentin. MATERIAL AND METHODS: One hundred twenty extracted bovine incisors were ground flat with 600-grit silicone carbide paper. Ninety teeth were then immersed in acetate buffer (pH 4.0) to form demineralized dentin. These teeth were randomly divided into 3 groups of 30 each: surfaces treated with fluoride solution (Group NF), surfaces treated with fluoride solution followed by a water rinse (Group RF), and control surfaces with no pretreatment (Group C). The remaining 30 teeth comprised a group with normal dentin surfaces (Group S). Each group was further divided into 3 subgroups of 10 each to test the bond strength test of Clearfil SE Bond, Unifil Bond, and Mac-Bond II. Tensile bond strengths (in MPa) were measured with a universal testing machine at a crosshead speed of 0.5 mm/min. Mean bond strengths were analyzed by 2-way analysis of variance and Fisher's PLSD (P =.05). SEM observations of the surfaces before and after priming and at resin-dentin interfaces in each group were performed. Elemental analysis of the dentin surfaces before priming was also carried out. RESULTS: The bond strengths of the adhesives to demineralized dentin in Groups NF, RF, and C were significantly lower than that of the normal dentin in Group S (P <.05). The mean bond strengths of the 3 adhesives in Group NF were higher than those in Groups RF and C, but a significant difference was observed only when Clearfil SE Bond was used (P <.05). In SEM images the open dentinal tubules on the surface and the resin tag formation at the resin-dentin interface were apparent in Group NF but were not observed in Groups RF and C. On elemental analysis, considerable amounts of fluoride and calcium were detected in the surfaces of Group NF. CONCLUSION: Within the limitations of this study, the surface treatment with fluoride solution supported the resin tag formation at the resin-dentin interface and slightly improved the bond strength of the self-etching adhesive systems tested to demineralized dentin. This result indicated that the fluoride treatment to demineralized dentin might contribute to the success of the sealed restoration.

Analysis of Variance↗

PubMed2006

The effectiveness of a fluoride varnish in preventing the development of white spot lesions.

A prospective examination of 10 consecutively treated orthodontic patients was undertaken to examine the effectiveness of fluoride varnish in reducing enamel demineralization. Pairs of dental quadrants for each patient's mouth (ie, maxillary right and mandibular left; maxillary left and mandibular right) were randomly assigned to an experimental or control group. After placement of resin-bonded orthodontic brackets, fluoride varnish was applied to the 2 experimental dental quadrants for each patient. Subsequent applications were done every 3 months during 12 months of orthodontic treatment. A double-blinded examination of intraoral photographs of the 100 experimental and 100 control teeth was done. The presence of white spot lesions was registered using the enamel decalcification index and the 2 groups were compared using paired Student t tests with a significance level of 5% (P < .05). There was no statistically significant difference between the mean enamel decalcification index for the control and experimental groups before or after treatment, since demineralization increased for both groups. Most importantly, the change in mean enamel decalcification index was significantly smaller for the experimental group (0.34), compared to the control group (0.51). In other words, there was 44.3% (P <.05) less demineralization noted for teeth that had been treated with fluoride varnish during orthodontic treatment.

Adolescent↗

PubMed1992

The effects of NaF, alpha-C12DMEAHF and alpha-C12DMEAHCl on caries development in dentine in situ.

Using histological techniques it was possible to demonstrate that during in situ caries development in bovine dentine, the demineralization process preceded the emergence and changes in the organic matrices. In addition, these data demonstrated as that 0.006% F- given either as the quaternary ammonium compound or NaF completely prevented demineralization by acting primarily on the dentine mineral. Inhibition by the quaternary ammonium compound alone was incomplete probably through repression of acid production by micro-organisms normally resident in the saliva.

Ammonium Chloride↗

PubMed1996

Effect of various demineralizing agents on mineral contents of cementum surfaces (an electron probe analysis).

The purpose of this investigation was to determine the surface morphology and mineral content of periodontally diseased cementum surfaces following root planing and conditioning with either citric acid, tetracycline HCL and minocycline HCL. Mineral contents of cementum surfaces were determined with an electron probe. All 3 demineralizing agents caused the exposure of the collagen matrix on the root surface but citric acid was the more effective. Calcium (Ca) and phosphorus (P) showed higher values in citric acid and minocycline HCL treated cementum surfaces compared to nondiseased cementum surfaces. The Ca and P were found to be in similar proportions in the tetracycline HCL treated group and nondiseased cementum surfaces. Although citric acid is a strong demineralizing agent, our specimens' cementum surfaces to which citric acid was treated showed high Ca and P content. In our opinion this difference about the effects of demineralizing agents on the surface morphology and surface element content was found to be related to the facts that whether the total amount of hypermineralized cementum as removed or not with root planing and the lacking criteria to detects the amount of this removal. Our findings suggest that these demineralizing agents can demineralize cementum surface after root planing but can not remove all of the hypermineralized diseased cementum. For this reason, it may be stated that it is more important to remove the pathologically altered cementum than applying various chemical agents.

Analysis of Variance↗

PubMed1996

A fiber-optic setup for quantification of root surface demineralization.

A fiber-optic fluorescence observation (FOFO) technique has been developed for the quantification of demineralized root dentin. The method was tested on 40 specimens of in vitro demineralized parts of human root dentin. Fluorescein sodium salt was used as a penetrating dye. The fluorescein sodium salt was excited using light around 465 nm. The fluorescence signal around 527 nm measured for demineralized dentin was corrected for lamp output and then divided by the corrected fluorescence signal for the sound control dentin on the same root, resulting in a FOFO-value. FOFO-values correlate linearly (r = 0.91) with mineral loss measured by transverse microradiography. Therefore, it was concluded that the FOFO-technique provides a good, non-destructive measure of the severeness of in vitro demineralized human root dentin, and is applicable on bulk dentin. Future work on natural lesions in vivo will be needed to investigate the applicability of the technique in a clinical situation.

Adolescent↗

PubMed1998

Dentin demineralization inhibition at restoration margins of Vitremer, Dyract and Compoglass.

PURPOSE: To examine the in vitro caries inhibition of a resin-modified glass ionomer cement (Vitremer-3M) and two compomers (Dyract-Dentsply; Compoglass-Ivoclar). MATERIALS AND METHODS: Standardized Class V preparations were placed in 40 molars, the gingival margin placed below the cementoenamel junction. Randomly, 10 Vitremer, 10 Dyract and 10 Compoglass restorations were placed according to manufacturer's instructions, in 30 teeth. Ten teeth received P-50 composite resin (3M) restorations and acted as the control. All teeth had an acid-resistant varnish placed to within 1 mm of restoration margins and they were then placed into artificial saliva for 4 weeks, the saliva being replenished every 48 hours. All teeth were subjected to an artificial caries challenge (pH 4.4) for 5 days. Sections of 100 microns were obtained, photographed under polarized light microscopy, and then digitized to quantitate demineralized areas adjacent to the restoration. RESULTS: The mean (+/- S.D) area (microns 2) demineralization 100 microns from the dentin/gingival margin was: Vitremer 4965 +/- 841, Compoglass 4981 +/- 2209, Dyract 5375 +/- 516, P-50 8088 +/- 2083. ANOVA and Duncan's (P < 0.05) indicated all three fluoride-releasing materials examined in this study had significantly less demineralization adjacent to restoration margins than the P-50 composite resin control. Seventy percent of glass ionomer cement restorations demonstrated adjacent dentin inhibition zones, while no dentin inhibition zones were demonstrated with the compomer restorations.

Analysis of Variance↗

PubMedDate not supplied

Preventive measures and caries progression: an in vitro study on fissures and smooth surfaces of human molars.

The aim of this study was to compare pit-and fissure sealants with fluoride treatments in their effectiveness to inhibit or reduce the progression of enamel lesions, particularly in the fissure region. The effects of fissure probing as used in diagnosis were compared with in the same protocol. Using a combination of image analysis of X-ray pictures of full crowns and a light microscopic evaluation of cross-sections provided information on the three dimensional spread of enamel demineralization. Pit-and-fissure sealants were superior in protecting enamel against progression of demineralization, as long as the walls of the fissures were well covered. The protection against demineralization offered by fluoride was mainly restricted to the smooth enamel surfaces; in fissures no protection could be measured. Surface defects of the enamel caused by probing or abrasion aided the progress of the lesion.

Amines↗

PubMed2004

Effects of solvents on the early stage stiffening rate of demineralized dentin matrix.

OBJECTIVES: To monitor the stiffening rate of demineralized dentin matrix at the early stages after exposure to different neat solvents. METHODS: Dentin beams approximately 0.8x0.7x8.0 mm were obtained from human third molars. After covering their ends with resin composite, the middle exposed length of 4.0mm (gauge-length) was demineralized in 0.5 M EDTA (pH 7.0) for 7 days. The specimens were gripped by a testing machine, pre-loaded to 10 g and cyclically stressed in tension to 5% strain, for 30 repeated cycles (total 20 min) at 0.6 mm/min while immersed in water (control). Then, water was replaced by either 100% acetone, methanol, ethanol, propanol, HEMA or air and the specimens subjected to the same cyclic protocol. The maximum apparent modulus of elasticity (E(Max)) was calculated for every cycle, plotted as a function of time and subjected to regression analysis. Stiffening rate was calculated as changes in E (min). Regression analysis examined the relationship between E and time for each solvent. Data were analyzed by one-way ANOVA and Student-Newman-Keuls test at alpha=0.05. RESULTS: Regression analysis showed that E increased significantly with time in all water-free solvents (R2=0.8-0.99). Stiffening rate was higher for acetone (0.9 MPa/min) and ethanol (0.8 MPa/min), intermediate for air (0.7 MPa/min), methanol (0.6 MPa/min) and propanol (0.5 MPa/min), lower for HEMA (0.2 MPa/min) and practically none for water (0.07 MPa/min) with p<0.05. CONCLUSIONS: The solvent-induced stiffening rate of demineralized dentin matrix is both time and solvent-dependent. The ability of solvents to promptly stiffen the demineralized dentin matrix may be important in maintaining the resin-infiltrated matrix expanded during the solvent evaporation stage of resin bonding.

1-Propanol↗

PubMed2001

In vivo diagnostic assessment of dentinal caries by junior and senior students using red acid dye.

The aim of this study was firstly to determine and compare the ability of inexperienced junior dental students (Fourth-year) and senior students (Fifth-year) versus a dental school instructor to identify demineralized dentine with the aid of a caries-disclosing solution and secondly to evaluate an eventual improvement of the caries diagnosis accuracy of junior (Fourth-year) and senior (Fifth-year) dental students. Three successive stages were used to check the ability of the dental students to diagnose and excavate the de-mineralized dentine. This study pointed out that 96% of junior dental students versus a teacher failed to remove all of the demineralized dentine without the use of a caries detector at the first stage and 79% at the second stage in the same condition. 100% of senior students versus a teacher, also failed to diagnose dental caries without a caries detector, but only at the first stage. However, at the second stage, unlike the junior students, all of the senior students were able to remove all of the demineralized dentine. Without the use of a caries detector dye, the risks of the dental students leaving demineralized dentine are high. This technique may be particularly helpful for the fourth-year students who are performing their first restorative treatment.

Anesthesia, Dental↗

PubMed2006

Criteria for a diagnosis of caries through the DIAGNOdent.

OBJECTIVE: The aim of this study was to investigate the correlation between the demineralization depth measured by dental computed tomography (CT) and the measured value from a non-destructive dental caries diagnosis with a laser. METHODS: Optimal cut-off points were obtained for enamel and dentin caries, from the measured levels from a dental caries diagnosis with a laser, to investigate the clinical usefulness of a diagnosis using a laser. Using human teeth, the demineralization depth was measured and the caries were diagnosed by a dental caries diagnosis with a laser. RESULTS: The optimal cut-off point was investigated for accuracy, sensibility, and specificity, which were calculated from the results. These results demonstrated the correlation between the measured values and demineralization depth in both the pit and fissure caries and smooth surface caries. The optimal cut-off points were found to be 16-21 in the fissure caries and 9-11 in the smooth surface caries.

Dental Caries↗

PubMed2004

The effect of a self-etching primer on the continuous demineralization of dentin.

Self-etching primers (SEP), used for adhesion of resin restorations, contain an acidic monomer that is not rinsed off after application; therefore, residual acid could further demineralize dentin, jeopardizing adhesion. This study evaluated whether dentin demineralization continues after a 20-s application of a SEP and also after polymerization of the adhesive. Surface recession was measured, using atomic force microscopy (AFM), between the masked surface and dentin etched with SEP (Clearfil SE Bond) or phosphoric acid (pH 1.94) immediately, 5 min, 2 h or 12 h after application. AFM-based nanoindentations were performed to determine mechanical property profiles across resin-bonded interfaces of two sequence groups: SG 1, where the adhesive was applied and polymerized immediately after application of the primer and specimens were immersed in Hank's solution after 5 min, 2 h and 12 h; or SG 2, where specimens were placed in an incubator before the application of the adhesive, for the same time periods. Significant surface recession occurred over time for all groups, except for SEP before desiccation. Nanoindentations yielded decreased hardness and elastic modulus below the hybrid layer after application of the initial primer, even after polymerization of the adhesive. The results reveal a demineralized dentin zone below the hybrid layer formed by the SEP, not fully protected by the adhesive, which could jeopardize bond strength.

Acid Etching, Dental↗

PubMed2004

Demineralization in enamel and hydroxyapatite aggregates at increasing ionic strengths.

Subsurface demineralization of dental enamel is a curious feature of both in vivo and in vitro lesion formation. Numerous explanations have been proposed to explain this. One general hypothesis is that subsurface demineralization in enamel and synthetic hydroxyapatite (HAP) aggregates may result from the phenomenon of coupled diffusion between the inward transport of acid and the outward transport of dissolution products. The aim of this study was to test the validity of this explanation. Inert electrolyte was added to demineralizing solutions in order to reduce electrostatic coupling between the diffusive flows that occur during lesion formation. Scanning microradiography (SMR) was used to examine surface layer formation, and to measure the rate of mineral loss at increasing ionic strengths. It was found that surface layer formation was significantly reduced as the concentration of inert electrolyte was increased. Further, the rate of mineral loss from the developing lesion increased as the concentration of inert electrolyte (and therefore the ionic strength) in the demineralizing solution increased. It is concluded that electrostatic coupling between counter diffusing acid and dissolution products during lesion formation can significantly influence the mineral concentration within the surface layer.

Dental Enamel↗

PubMed1994

Air-rotor stripping and enamel demineralization in vitro.

This investigation sought to evaluate the effects of air-rotor stripping on the susceptibility of human enamel to demineralization using an in vitro caries model. Crowns of extracted premolar teeth were abraded (0.5 mm) on one proximal surface by air-rotor stripping. The teeth were placed in a demineralizing gel and removed at various intervals up to 336 hours. Lesion depth and mineral content on the abraded and intact surfaces was measured with contact microradiography and computerized image analysis (double window technique). For each time interval measured, lesion depth was greater (p < 0.05) on the abraded surfaces and mineral density was significantly less (p < 0.05). In a second experiment, the effect of fluoride supplements (dentifrice or topical gel) were examined on abraded and intact enamel surfaces that were exposed to the acid gel for 192 hours. The data showed that fluoride treatments significantly reduced lesion penetration on intact and abraded surfaces compared with a no fluoride group. Lesion depth on the abraded, fluoride treated surfaces was significantly greater (p < 0.05) than on the intact untreated surfaces. No significant differences (p < 0.05) were apparent between the fluoride treatment groups with respect to lesion depth and mineral density within the lesion. These results suggest that air-rotor stripping significantly increases the susceptibility of proximal enamel surfaces to demineralization. As a result, the clinician should use caution in the application of this technique until the long-term effects on caries susceptibility have been determined.

Acidulated Phosphate Fluoride↗

PubMedDate not supplied

In vitro studies of the penetration of adhesive resins into artificial caries-like lesions.

Instead of removing the porous carious tissue at a relatively late stage in the disease process, attempts have been made to 'fill' the microporosities of lesions at a much earlier stage of lesion development. This would not only reduce the porosity and therefore access of acid and egress of dissolved material, but also afford some mechanical support to the tissue and perhaps inhibit further attack. Successful infiltration of materials into lesions has been demonstrated previously using resorcinol-formaldehyde which, however, was clinically unacceptable. The advent of dental adhesives with potentially suitable properties has prompted a re-examination of this concept. Artificial lesions of enamel were generated in extracted human teeth using acidified gels. A range of currently available adhesive materials was then used to infiltrate the porosities. The extent of occlusion of the lesion porosities was determined both qualitatively using light microscopy and quantitatively using a chloronaphthalene imbibition technique. The effect of such treatment upon subsequent exposure to acid gels was also investigated. Results showed that up to 60% of the lesion pore volume had been occluded following infiltration with some of the materials and that this treatment was capable of reducing further acid demineralization. The development of such treatment strategies could offer potential noninvasive means of treating early enamel lesions.

Adhesives↗