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Copyright of Revista Foco (Interdisciplinary Studies Journal) is the property of Revista Foco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: The loss of the interdental papilla is one of the adverse events that can occur after periodontal therapy. It can cause food impaction, aesthetic deformities and phonetic problems. The objective of this study was to evaluate the effect of the distance from the contact point to the crestal bone on the degree of vertical loss of interdental papillae. Study design: A total of 125 interproximal sites from 26 patients were examined. Prior to transperiodontal bone probing, the class of the interdental papilla was determined based on the classification system developed by Nordland and Tarnow. The distance from the contact point to the crestal bone was measured by probing under local anaesthesia. Results: The results revealed that when the distance from the contact point to the crestal bone was ≤ 5 mm, in 98.4% of the cases the papilla did not shrink. When the distance was ≥ 7 mm, 100% of papilla shrinkage was classified as class III. A significant association (Fisher exact test, P < 0.001) was observed between the degree of loss of interdental papilla and the distance from the contact point to the bone crest. Conclusion: The distance of the base of the contact point to the coronal portion of the bone crest measured by bone probing is highly associated with the degree of the vertical loss of the interdental papilla. [ABSTRACT FROM AUTHOR]

Objective: The purpose of this in vitro study was to determine the microtensile bond strengths (µTBS) of 3 dental adhesives when applied to dentin decalcified with ethylenediaminetetraacetic acid (EDTA). The null hypothesis tested was that the removal of calcium from dentin would not influence the bond strengths. Methods and materials: Eighteen extracted human molars were cut in 2 equal halves. One half served as the control, having no EDTA treatment, while the other half was assigned to 1 of 3 periods (1 hour, 24 hours, or 100 hours) of decalcification with buffered 0.5 mol/L EDTA. Middle dentin was bonded with 1 of 3 dental adhesive groups: a self-etching primer, Clearfil SE Bond (SE); an acetone-based total-etch adhesive, Prime&Bond NT (NT); and an ethanol- and water-based total-etch adhesive, Single Bond (SB). The specimens were restored with Z-250 resin composite and sectioned in 0.9 ± 0.2 mm² sticks that were tested in tensile mode. Results: For each adhesive, the control group (not decalcified) resulted in statistically higher bond strengths than the treatment groups. For specimens that were not decalcified, SE and SB had statistically similar bond strengths, but both resulted in statistically higher bond strengths than NT. For specimens decalcified for 1 hour, SE resulted in statistically higher bond strengths than either SB or NT, which were ranked in the same statistical group. SE was the only dentin adhesive to result in measurable µTBS after decalcification with EDTA for 24 hours, while SB/24 hour and NT/24 hour specimens debonded spontaneously prior to testing. All the specimens treated with EDTA for 100 hours debonded prior to testing. Conclusion: Three conclusions were drawn: (1) All 3 adhesive systems included in this project bonded significantly better to calcified than to decalcified dentin, regardless of their composition; (2) The self-etching primer-based adhesive ranked consistently equal to or better than the 2 total-etch-based adhesives, regardless of the EDTA decalcification time; and (3) removal of calcium may be more detrimental for adhesives that rely on dentin acid etching than for adhesives based on self-etching primers. (Quintessence Int 2001; 32: 142-146) [ABSTRACT FROM AUTHOR]

Objective: Dental adhesion has become one of the most challenging topics of restorative dentistry. Acids are now applied on dentin to improve adhesion. If the acid penetrates deeper than the adhesive resin subsequently applied, an area of vulnerable collagen fibers may weaken the bonding. This in vitro study was designed to evaluate the effect of etching time on the depth of dentin demineralization, using Field Emission Scanning Electron Microscopy. The null hypothesis tested was that the depth of dentin demineralization would not vary proportionally with etching time. Method and materials: Twenty-one dentin disks were obtained from extracted human molars by diamond saw sectioning. The specimens were equally assigned to 7 different etching times (n = 3). The dentin surfaces were etched with 35% phosphoric acid, fixed, dehydrated, and dried. The specimens were observed using a Field Emission Scanning Electron Microscope. The morphological appearance of the dentin surfaces was compared both from an occlusal view and from a lateral view. The depth of demineralization of intertubular dentin was registered for all specimens. Results: For an etching time of 5 seconds, the mean depth of demineralization was 1.1 μm. For an etching time of 120 seconds, the mean depth of dentin demineralization was 8.1 μm. Conclusion: Although there was a significant correlation between etching time and depth of intertubular penetration, the depth of phosphoric acid penetration into dentin was not proportionally correlated to the respective etching time. When the acid was replenished with fresh etchant after 60 seconds, the depth of penetration increased substantially. [ABSTRACT FROM AUTHOR]

Purpose: The objective of this review article is to summarize the most recent concepts in dentin bonding and, simultaneously, challenge some convictions that have not been backed up by sound, convincing research. After the introduction of the enamel acid-etch technique by Dr. Buonocore in 1955, the increasing demand for restorative and non-restorative esthetic treatments, as well as the refinement in the utilization of fluoride-containing products, have totally transformed the practice of operative dentistry. While bonding to enamel is a reliable technique, bonding to dentin represents a greater challenge: dentin is an intrinsically wet organic tissue penetrated by a tubular labyrinth containing the odontoblastic process, which communicates with the pulp. The manufacturers of new adhesive systems recommend the application of their adhesive materials on moist dentin. The main reason is that the spatial alteration that occurs upon drying demineralized dentin may prevent the monomers from penetrating the labyrinth of nano-channels formed by dissolution of hydroxyapatite crystals between collagen fibrils. Several of the current concepts in dentin bonding have been built from the observation of clinical studies, which measure retention rates, and from laboratory bond strength studies, which measure the force needed to debond a composite post from a flat dentin area. Although their utility is doubtful as far as clinical performance is concerned, bond strength studies are still necessary in order to compare similar parameters among materials. However, both clinical and laboratory studies lack information on the dynamic behavior of the substrate in a vital environment. For example, the changes induced by adhesive systems in the resin-infiltrated demineralized dentin have not been fully characterized. Also, the role of collagenous and non-collagenous proteins in dentin bonding has been generally overlooked. [ABSTRACT FROM AUTHOR]

Purpose: To compare the immediate microtensile bond strengths (pTBSs) of four mild self-etch universal adhesives applied to dentin and enamel with self-etch and etch-and-rinse techniques. Methods: Flat middle dentin surfaces from 104 human teeth and two enamel fragments from another 104 human teeth were randomly distributed into eight groups according to the various adhesive systems used: Scotchbond Universal (SBU) [etch-and-rinse mode vs. self-etch mode]; Optibond XTR (OPT) [etch-and-rinse mode vs. self-etch mode]; Clearfil Universal Bond Quick (CL) [etch-andrinse mode vs. self-etch mode]; and Adhese Universal (ADH) [etch-and-rinse mode vs. self-etch mode]. After 24 hours of water storage, the bonded sticks were tested for pTBS. The differences in the pre-test failure and fracture-failure modes were tested by a two-way ANOVA and GEE model analysis. Bond-strength data were analyzed with a two-way ANOVA and mixed-model analysis. Results: For dentin, the mean pTBS was statistically different among the four adhesives, but not different between the self-etch and etch-and-rinse modes. For enamel, the mean pTBS was statistically different among the four adhesives, as was the application mode. GEE model analysis revealed a statistically significant adhesive failure rate proportion among the four types of adhesives for both enamel and dentin. [ABSTRACT FROM AUTHOR]