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At least 1,207 records · Page 67Linked to original sources
PubMed2006

Estrogen and alendronate therapies may prevent the influence of estrogen deficiency on the tooth-supporting alveolar bone: a histometric study in rats.

BACKGROUND AND OBJECTIVE: The aim of this study was to evaluate histometrically the influence of estrogen deficiency, and its therapies, on the quality of the tooth-supporting alveolar bone. MATERIAL AND METHODS: Seventy-three female rats were randomly assigned to one of the following groups: group 1 (n = 15), sham surgery; group 2 (n = 15), bilateral ovariectomy (OVX); group 3 (n = 14), OVX plus calcitonin (16 IU/kg); group 4 (n = 14), OVX plus estrogen (20 microg/kg); and group 5 (n = 15), OVX plus alendronate (5 mg/kg). Eighty days after surgery, the animals were killed and their mandibles were removed and processed for histology. Bone density (BD) in the furcation area of the first mandibular molar (i.e. the percentage of demineralized bone tissue in a 1,000 microm zone under the furcation) was histometrically obtained. RESULTS: Data analysis demonstrated that estrogen deficiency negatively affected the tooth-supporting bone density (79.45% +/- 4.22 and 55.23% +/- 6.45, for groups 1 and 2, respectively), and that estradiol and alendronate therapies prevented this effect (61.67% +/- 6.87, 78.09% +/- 3.12 and 81.47% +/- 4.58, for groups 3, 4 and 5, respectively). CONCLUSION: Within the limits of this study, it can be concluded that the density of tooth-supporting bone is affected by estrogen deficiency, and that estradiol and alendronate therapies, but not calcitonin, provide protection against this effect.

Alendronate↗
PubMed2001

Syndromes with salivary dysfunction predispose to tooth wear: Case reports of congenital dysfunction of major salivary glands, Prader-Willi, congenital rubella, and Sjögren's syndromes.

Four cases-of congenital dysfunction of the major salivary glands as well as of Prader-Willi, congenital rubella, and Sjögren's syndromes-were identified in a series of 500 patients referred for excessive tooth wear. Although there was evidence of consumption of highly acidic drinks, some occlusal parafunction, and unacceptable toothbrushing habits, salivary dysfunction was the salient factor predisposing a patient to tooth wear in these syndromal cases. The 500 subjects have been characterized either as having medical conditions and medications that predispose them to xerostomia or lifestyles in which workplace- and sports-related dehydration lead to reduced salivary flow. Normal salivation, by buffering capacity, clearance by swallowing, pellicle formation, and capacity for remineralization of demineralized enamel, protects the teeth from extrinsic and intrinsic acids that initiate dental erosion. Thus, the syndromes, unrelated in many respects, underline the importance of normal salivation in the protection of teeth against tooth wear by erosion, attrition, and abrasion.

Adult↗
PubMed2005

Tensile strength of mineralized/demineralized human normal and carious dentin.

The bond strengths of resins to caries-affected dentin are low. This could be due to weakened organic matrix. The purpose of this work was to determine if the ultimate tensile strength (UTS) of excavated carious dentin is weaker than that of normal dentin. Soft caries was excavated from extracted human molars, and the tooth was vertically sectioned into slabs. Each slab was trimmed to an hourglass shape, parallel or perpendicular to the tubule direction. Half of the specimens were mineralized, while the other half were completely demineralized in EDTA. ANOVA on ranks showed that the three-factor interactions (mineralization, caries, tubule direction) were all significant (p < 0.0001), indicating that mineralization and tubule direction gave different UTS results in normal and caries-affected dentin. No significant differences were seen between the UTS of normal and and that of caries-affected demineralized dentin in the parallel or perpendicular group. The matrix of demineralized caries-affected dentin was as strong as that of normal demineralized dentin when tested in the same direction.

Chelating Agents↗
PubMed2003

Mineralization of basement membrane mediates dentogingival adhesion in mammalian and nonmammalian vertebrates.

In order to elucidate the mechanism of adhesion between the gingiva and the tooth, detailed comparative ultrastructural studies of the dentogingival border were done in the monkey and shark. The tissues were prepared with or without demineralization for the ultrastructural observations. At the border, the internal basement membrane, which is firmly bound to the junctional epithelium through hemidesmosomes, was specialized differently in these species. In the monkey, the lamina densa was closely associated at its enamel side with an additional layer which had characteristics of the lamina densa and was referred to as the supplementary lamina densa. In the shark, the lamina densa showed a unique, hemidesmosome-related specialization in the form of the intermittent occurrence of bulges along its surface facing the epithelium. In nondemineralized tissues a part of the basement membrane, that is, the supplementary lamina densa (monkey) and the main lamina densa but not bulges (shark), was preferentially mineralized. The mineral deposit was continuous with that in the enamel and enameloid/dentine, thus constituting an advancing edge of mineralization. The network arrangement of the mineral crystals in the monkey basement membrane resembled the pattern of the cord network of the basement membrane, suggesting the presence of a delicate mutual basement membrane-mineral interaction. Thus, the organic phase and the mineral phase are allowed to make contact at this mineralized area of the basement membrane and firmly bind to one another. Therefore, strong gingiva-tooth adhesion is established by partial mineralization of the internal basement membrane, in a way similar to that found in the previously reported association of maturation stage ameloblasts with the enamel.

Animals↗
PubMed1997

Adherence of "stuck" restorations to demineralized dentin following use of experimental primers.

PURPOSE: This in vivo study histopathologically evaluated the biocompatibility of four self-conditioning dentinal primer formulas in four bonding systems and evaluated the pulpal responses of the self-conditioning dentinal bonding systems for Class V tooth preparations in primates. MATERIAL AND METHODS: The basic formula consisted of proprietary carboxylic diacid monomer, dipentaerythritol pentaacrylate phosphoric acid ester, acetone, and ethanol that was used alone or mixed with other commercial priming agents. After application of primers, Prisma Universal Bond 3 was selected to restore the cavity preparations. RESULTS: All systems were judged histopathologically biocompatible. "Stuck" restorations that were resistant to acid demineralization necessary for processing of histologic slides, occurred more frequently with intact smear layers and increasing use of dehydrating agents. CONCLUSIONS: Tests should be performed to determine whether "stuck" restorations in in vivo studies that maintain dentin-pulpal relationships can support in vitro shear bond strength tests.

Acetone↗
PubMed1993

Cellular retinoic acid binding protein in the periodontal ligament.

As retinoic acid is an important signaling molecule during embryological development. Since periodontal tissues are thought to have fetal-like properties, the present study was to determine the presence and distribution of cellular retinoic acid-binding protein I(CRABPI) in the periodontal tissues of the rat. Following demineralization, wax sections of the molar teeth of four adult male rats were cut in a plane parallel to the molar tooth row. Five representative sections from each jaw were then processed and stained to reveal the presence of CRABP. This protein was identified by immunochemistry utilizing an affinity-purified rabbit polyclonal antibody. The IgG antibody was used at a dilution of 1 microgram ml-1 and immunoreactivity detected with a kit according to protocol. Immunoreactivity was detected with diaminobenzidine and sections counterstained with hematoxylin. Results showed that virtually all the cells of periodontal ligament, the vast majority representing fibroblasts, contained CRABP. Fibroblasts in the gingiva above the level of the alveolar crest also stained positively for CRABP. The periodontal tissues of all three molar teeth were similarly affected. Fibroblasts in other regions of the oral cavity, such as the dermis of the skin of the cheek or the lamina propria of the buccal mucosa or of the diastema region, exhibited little or no staining for CRABP. Because of its properties as a signaling molecule and its ability to interact with other regulatory molecules, retinoic acid and cellular retinoic acid-binding protein may play an important role in the biology of the periodontal tissues.

Animals↗
PubMed1998

Conventional glass ionomers as posterior restorations. A status report for the American Journal of Dentistry.

The search for a material to replace amalgam continues as a major quest in materials science. Resin composites may offer one solution but an alternative class of material, the glass ionomer cements (GICs) may have some potential for fulfilling this role. GICs were first introduced to the dental profession in 1976, and have now become an accepted part of the dental armamentarium, especially for use in low load bearing situations. They possess a low coefficient of thermal expansion similar to that of tooth structure, physicochemical bonding to both enamel and dentin, and the release of fluoride ions into the adjacent tooth tissue. These properties help to reduce marginal leakage and may contribute to a reduced incidence of recurrent decay in the restored tooth. Fluoride released into the ambient fluids has a caries-preventive effect in neighboring teeth by enhancing remineralization and inhibiting demineralization of the dental hard tissues. The main criticisms of the GICs are their brittleness, poor surface polish, porosity and surface wear. To overcome some of these deficiencies, considerable attention has been directed at improving their physical properties, especially with the addition of metal powders, the metal-modified GICs. Different metal powders have been tried, including alloys of silver and tin, pure silver, gold, titanium, palladium and stainless steel. There is conflicting data as to whether or not these materials are sufficiently strong for use in high stress restorations, especially their potential use as replacement materials for amalgam fillings.

Bicuspid↗
PubMed2003

[Carisolv, a change in the perception of caries treatment--a chemo-mechanical removal of caries].

This paper reviews the chemo-mechanical method (Carisolv) for caries removal. The mechanism of action and some treatment choices are described. Modern dentistry aims to preserve tooth structure by minimal invasive procedures. Chemo-mechanical removal of caries is a new method with the advantage of selective removal of severely demineralized dentin. This enhances the caries diagnostic ability of the clinician. Ensuring chair side caries diagnosis and removal, based on a biological principle, helps to preserve as much healthy tissue as possible. This method is most comfortable for the patient. On the other hand treatment time is prolonged. In most cases, the method has to be used in combination with a conventional bur. Caries lesions in which removal of enamel or a restoration is needed cannot be treated exclusively by the chemo-mechanical method. However, the chemo-mechanical caries treatment can be used as the first choice of treatment in specific cases in the prosthodontic and pediatric field.

Child↗
PubMed1991

Comparison of the plaque microflora from natural and appliance-borne enamel surfaces.

Human enamel sections and slabs, mounted on a mandibular removable appliance, were worn by 5 adult subjects for a 1-week period. Plaque was allowed to accumulate on the in situ test sites and on the adjacent natural dentition. At the end of the experimental period, the plaque microflora associated with (1) the enamel sections, (2) the enamel slabs, and (3) the acrylic base of the appliance test site was compared with that obtained from lingual and interproximal areas of the lower molar teeth. In addition, the acid anion and pH profiles of plaque obtained from both the exogenous and natural tooth surfaces were also determined. Although some quantitative differences were found between the proportions of isolates obtained from the different enamel surfaces, qualitatively the microflora was very similar, and no significant differences were found in the plaque lactate/acetate ratios or pH measurements following a sucrose mouthrinse. Thus, human tooth specimens mounted on the intra-oral device produced a plaque ecosystem similar to that present on the adjacent natural dentition, suggesting that the model is suitable for studies on early plaque development and the microbiology of enamel demineralization.

Acrylic Resins↗
PubMed1999

Review of fluoride research since 1959.

The evidence for the two main hypotheses proposed for the mode of action of F in reducing caries is reviewed. The current conclusion is that low concentrations of F in plaque, which need frequent renewal, favour remineralization of dental tissue (i.e. a net reduction of demineralization) in the later stages of a cariogenic episode. This replaces the other view that a high concentration of F in the tooth mineral reduces its solubility.

Dental Caries↗
PubMed1994

Resorption patterns following intentional vital root transection in Macaca mulatta.

Previous studies have shown degeneration of nerve tissue as well as reorganization by periodontal tissue in dental pulp chambers following intentional vital root transection in Macaca mulatta. The supporting structures of the teeth, as well as the root itself, have not been fully studied following such surgery. The purpose of this study was to observe histopathologic changes in bone and root structure over a 1-year postoperative period. Three adult Macaca mulatta were evaluated for this study. Roots were transected within the apical one third and the areas were surgically closed. Following a postoperative soft diet for 7 days, the monkeys were allowed normal masticatory function. Maxillary and mandibular quadrants were removed following vascular perfusion of the animals at 1, 2, 3, 6, 24, and 52 weeks; quadrants were then demineralized, embedded, sectioned, and stained with Preece's trichrome. Resorption of cementum, dentin, and bone was independently evaluated on microslides for each tooth at consecutive intervals of approximately 70 microns. Resorption was rated as mild, moderate, or severe depending on the number of Howship's lacunae and the dimension of the resorptive area. Severe bone resorption was evident at 1 week, decreasing at 2 weeks, and then progressively decreasing up to 52 weeks. Most active inflammatory root resorption was noted on maxillary and mandibular premolars and molars on first-week specimens. Arrested resorptive areas were present in similar locations in second- and third-week specimens. New cementum was present along the cut surface on specimens from 2 to 52 weeks and within the pulp canal beginning at 2 weeks.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2003

Effect of dexamethasone on root resorption after delayed replantation of rat tooth.

The purpose of this study was to evaluate the effect of dexamethasone after delayed tooth replantation with specific regard to root resorption and ankylosis. In addition, the study was planned to elucidate further the usefulness of the model. Fifty-two maxillary first molar teeth were extracted from 26 Sprague-Dawley white female rats fed 0.4% beta-aminoproprionitrile for 3 days to facilitate the extraction. After extraction, the mesiobuccal root canals were endodontically treated under a microscope to prevent subsequent inflammatory resorption of pulpal origin and were assigned to three groups. Teeth in group 1, the dexamethasone group (n = 22), were demineralized in citric acid (1 min), washed, soaked in 1000 nM dexamethasone solution (3 min), air-dried, and replanted in the original sockets. Total extraoral treatment time for each tooth was controlled to 30 min. Teeth in group 2, the dried-only group (n = 22), were air-dried for 30 min after obturation without any surface treatment and replanted. Teeth in group 3, the immediate group (n = 8), were extracted, not root-filled and replanted immediately into their sockets. All experimental animals were killed at 3 weeks after replantation and evaluated histologically. Forty-three of the 52 teeth were available for histological interpretation. They consisted of six immediate, 18 dried-only, and 19 dexamethasone-treated teeth. The degree of progressive root resorption was significantly less in the dexamethasone-treated group than in the dried-only group (p < 0.05). The dexamethasone-treated group exhibited significantly more bone ankylosis than the dried-only group (p < 0.05). These results indicate that the topical use of dexamethasone may be of value in reducing the degree or rate of progressive root resorption secondary to traumatic avulsion and that the rat is a reasonable model for tooth replantation.

Administration, Topical↗
PubMed2006

Biological factors.

Biological factors such as saliva, acquired dental pellicle, tooth structure and positioning in relation to soft tissues and tongue are related to dental erosion development. Saliva has been shown to be the most important biological factor in the prevention of dental erosion. It starts acting even before the acid attack, with the increase of the salivary flow rate as a response to the acidic stimuli. This creates a favorable scenario, increasing the buffering system of saliva and effectively diluting and clearing acids on dental surfaces during the erosive challenge. Saliva plays a role in the formation of the acquired dental pellicle, which acts as a perm-selective membrane preventing contact of the acid with the tooth surfaces. The protective level of the pellicle seems to be regulated by its composition, thickness and maturation time. Due to its mineral content, saliva can also prevent demineralization as well as enhance remineralization. However, these preventive and reparative factors of saliva may not be enough against highly erosive challenges, leading to erosion development. The progress rate of erosion can be significantly influenced by the type of dental substrate, occurrence of mechanical and chemical attacks, fluoride exposure, and also by contact with the oral soft tissues and tongue.

Biology↗