SEARCH · PubMed Health

Results for “Tooth Demineralization”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources

PubMed1998

Enamel demineralization adjacent to orthodontic brackets bonded with hybrid glass ionomer cements: an in vitro study.

Enamel demineralization is recognized as a possible side effect of bonding orthodontic brackets with composite resins. Fluoride-releasing restorative materials have been shown to inhibit tooth demineralization. The purpose of this study was to evaluate two fluoride-releasing hybrid glass ionomer bonding agents for inhibition of enamel demineralization surrounding orthodontic brackets under two experimental conditions. This in vitro study used 72 extracted human premolars. Twenty-four teeth were bonded with Advance resionomer, 24 were bonded with Fuji Ortho LC hybrid glass ionomer and 24 were bonded with Transbond XT composite resin as the control. The teeth were cycled in an artificial caries challenge three times daily for 30 days. Half of the teeth in each group were brushed twice daily with a fluoridated dentifrice, and the other half were not brushed. Demineralization of enamel surrounding orthodontic brackets was evaluated with polarized light microscopy. Enamel lesions were photographed under maximum illumination. Images were projected, and demineralized areas were traced. Both average depth and area were measured with a sonic digitizer. Analysis of variance (P <.0001) and Duncan's test (P <.05) indicated significant differences in depth and area of demineralized enamel such that lesion size was: Transbond XT no brush > Transbond XT brush > Advance no brush = Advance brush = Fuji Ortho LC no brush = Fuji Ortho brush. The promising results of this in vitro study warrant further clinical investigation of hybrid glass ionomer adhesives as orthodontic bonding agents to minimize enamel demineralization.

Acrylic Resins↗

PubMed2002

A mixed-bacteria ecological approach to understanding the role of the oral bacteria in dental caries causation: an alternative to Streptococcus mutans and the specific-plaque hypothesis.

For more than 100 years, investigators have tried to identify the bacteria responsible for dental caries formation and to determine whether their role is one of specificity. Frequent association of Lactobacillus acidophilus and Streptococcus mutans with caries activity gave credence to their being specific cariogens. However, dental caries occurrence in their absence, and the presence of other bacteria able to produce substantial amounts of acid from fermentable carbohydrate, provided arguments for non-specificity. In the 1940s, Stephan found that the mixed bacteria in dental plaque produced a rapid drop in pH following a sugar rinse and a slow pH return toward baseline. This response became a cornerstone of plaque and mixed-bacterial involvement in dental caries causation when Stephan showed that the pH decrease was inversely and clearly related to caries activity. Detailed examination of the pH (acid-base) metabolisms of oral pure cultures, dental plaque, and salivary sediment identified the main bacteria and metabolic processes responsible for the pH metabolism of dental plaque. It was discovered that this metabolism in different individuals, in plaque in different dentition locations within individuals, and in individuals of different levels of caries activity could be described in terms of a relatively small number of acid-base metabolic processes. This led to an overall bacterial metabolic vector concept for dental plaque, and helped unravel the bacterial involvement in the degradation of the carbohydrate and nitrogenous substrates that produce the acids and alkali that affect the pH and favor and inhibit dental caries production, respectively. A central role of oral arginolytic and non-arginolytic acidogens in the production of the Stephan pH curve was discovered. The non-arginolytics could produce only the pH fall part of this curve, whereas the arginolytics could produce both the fall and the rise. The net result of the latter was a less acidic Stephan pH curve. Both kinds of bacteria are numerous in dental plaque. By varying their ratios, we were easily able to produce Stephan pH curves indicative of different levels of caries activity. This and substantial related metabolic and microbial data indicated that it is the proportions and numbers of acid-base-producing bacteria that are at the core of dental caries activity. The elimination of S. mutans, as with a vaccine, was considered to have little chance of success in preventing dental caries in humans, since, in most cases, this would simply make more room for one or more of the many acidogens remaining. An understanding of mixed-bacterial metabolism, knowledge of how to manipulate and work with mixed bacteria, and the use of a bacterial metabolic vector approach as described in this article have led to (1) a more ecological focus for dealing with dental caries, and (2) new means of developing and evaluating anti-caries agents directed toward microbial mixtures that counter excess acid accumulation and tooth demineralization.

Animals↗

PubMed1999

Release of mineral ions in dental plaque following acid production.

The release of appreciable amounts of calcium, phosphate and fluoride found in whole plaque into the plaque-fluid phase, following bacterial acid production, can potentially reduce the driving force for tooth demineralization. However, limited information is available on this topic, particularly on the release of fluoride. This study sought to determine the change in calcium, phosphate and fluoride concentrations in plaque fluid after sucrose exposure. 48 h overnight-fasted supragingival plaque samples were collected from all tooth surfaces (with the exception of the lower lingual anterior teeth) of one half of an individual mouth, following a 1 min water rinse. Plaque samples were then collected from the other half of the same mouth, following a 292 mM sucrose rinse. Plaque fluid was isolated by centrifugation and analysed for total calcium and phosphate (ion chromatography) and for free fluoride (ion-specific electrode). Samples were collected from seven individuals. Following sucrose exposure, plaque-fluid pH decreased significantly from 6.5+/- 0.3 to 5.4+/-0.2; calcium concentrations (mmol/l) also increased significantly (p < 0.01) from 1.9+/-0.5 to 5.0+/-2.1. Fluoride and phosphate concentrations in plaque fluid, however, did not increase significantly after sucrose exposure: mean concentrations (mmol/l) of fluoride after the water and sucrose rinses were 0.006+/-0.003 and 0.005+/-0.002, respectively, and mean phosphate concentrations (mmol/l) were 11.0+/-2.0 and 12.0+/-3.0, respectively. When results were expressed per wet plaque weight, phosphate concentrations were also found to increase significantly. The same trends were observed when additional plaque samples were treated in vitro with sucrose: fluoride-ion activity did not increase in plaque under in vivo-like conditions.

Adolescent↗

PubMed2005

Defining, classifying, and placing incipient caries lesions in perspective.

A caries lesion begins with the introduction of a disease state, likely due to bacterial strains, in the oral cavity. If accompanied or followed by alterations to salivary flow, frequent periods of reduced salivary pH, or frequent intake of refined carbohydrates, the demineralization of tooth structure is likely to begin. The subsequent lesions first will be visible as white spot lesions, which if ignored, eventually will cavitate. Modern dentistry is capable of testing for the presence of caries lesions before cavitation, and it is suggested that routine testing should be mandatory for all patients who are at risk. If the disease is to be identified and treated before cavitation, it is desirable to adopt a new classification for the recognition and recording of caries lesions.

Dental Caries↗

PubMed1996

[Micro-abrasions of enamel: an alternative to the elimination of superficial demineralization and decalcification].

Tooth discoloration's may cause serious damage to the aesthetic appearance of the patients. These discoloration's can be treated in several ways but up to lately tooth structure had to be removed in an irreversible manner in order to provide sufficient bulk for the new restorative material. Nowadays thanks to the work of T. Croll and others a method has been established in a scientific way whereby tooth discoloration's confined to the outermost layer of enamel can be removed, through the application of an compound called PREMA which will simultaneous erode and abrade the enamel surface. If carefully selected the discoloration can be removed with only a limited loss of tooth structure. The authors describe the historical background of the method. Furthermore patient's selection, specific instruments and materials are described in detail. The clinical procedure is explained step by step, followed by a complete report of the effects of the procedure on the different tooth structures. Finally the long term results are discussed and the possibility to enhance the result by combining this method with home bleaching.

Complex Mixtures↗

PubMed2000

Minimal intervention: early lesions.

The use of modified cavity designs for the treatment of initial carious lesions can be justified on the grounds that, because no restorative material can adequately replace natural tooth structure for the long term, preservation of natural tooth structure is important. It is apparent that it is possible to remineralize and heal demineralized tooth structure to some degree. Therefore, neither enamel nor dentin should be removed simply because it has lost calcium and phosphate ions as a result of acid attack. The older surgical approach to cavity design was adopted in the absence of adhesive techniques and on the basis of Black's principle of "extension for prevention," but this theory is no longer tenable. The current availability of adhesive bioactive restorative materials makes it possible to maintain areas of tooth structure even though they appear to be undermined and weakened. Thus, the concept of geometric designs for prescribed cavities is no longer valid. The purpose of this article is to describe a series of simplified, modified cavity designs for small initial lesions; preservation of natural tooth structure is the principle objective of these designs.

Dental Caries↗

PubMed1992

Three-dimensional changes in direction and interrelationships among enamel prisms in the dog tooth.

This study describes the three-dimensional features of enamel prisms and their arrangement in dog teeth. Tangential semithin sections of demineralized tooth germ were serially cut from the enamel surface to the enamel-dentin junction. Straight rows of enamel prisms parallel or perpendicular to the meridian were selected at the enamel-dentin junction; these prisms were reconstructed from micrographs with a personal computer. Near the enamel-dentin junction, the arrangement of enamel prisms appeared regular. Viewed from the enamel surface, the cut-ends of the enamel prisms that were parallel to the meridian at the enamel-dentin junction appeared as a sine curve, with 16 enamel prisms forming one period. The enamel prisms in a row perpendicular to the meridian were parallel to each other and deflected to the left or right from the enamel-dentin junction. Away from the enamel-dentin junction, the periodicity of the prisms gradually disappeared. The sine curve formed by the cut-ends of prisms in a row parallel to the meridian became irregular, and prisms in rows perpendicular to the meridian crossed each other. The semithin sections showed belt-like zones arranged perpendicular to the meridian. Each belt-like zone consisted of enamel prisms oriented in the same direction, those in neighboring zones being oriented in opposite directions. The disappearance of the regular arrangement of prisms was related to changes in their location in the belt-like zones.

Animals↗

PubMed1996

Three-dimensional arrangement of enamel prisms and their relation to the formation of Hunter-Schreger bands in dog tooth.

The three-dimensional architecture of enamel prisms and their relationship to Hunter-Schreger bands were examined in the developing enamel of several dog teeth by light and electron microscopy, and computer-assisted reconstruction. Sections were prepared from a single demineralized tooth germ. Longitudinal semithin sections parallel to the meridian of the tooth showed parazones and diazones of the Hunter-Schreger bands in alternate rows at equal intervals. On sections vertical to the tooth crown through the middle region of parazone or diazone, a row of parallel prisms were angulated with the largest tilting angle being 55 degrees to the enamel-dentin junction, running in opposite directions in the respective zones. Tangential sections parallel to the enamel-dentin junction showed numerous belt-like zones arranged perpendicular to the meridian of the tooth. Each belt-like zone consisted of a group of enamel prisms oriented in the same direction, those in the neighboring zones being oriented in an opposite direction. The densely stained boundaries between the adjacent belt-like zones corresponded to the interface between parazone and diazone. Computer-reconstructed enamel prisms in the adjacent two zones were oriented in the opposite sidewards direction with occasional confluence and divergence. Scanning electron-microscopic observation of the developing enamel surface exposed by dissolution of the enamel organ revealed band-like arrangements of groups of pits encasing the Tomes' processes of secretory ameloblasts. The secretory faces of the pits inclined uniformly in the same sidewards direction, with those in the neighboring groups, in the opposite direction.

Animals↗

PubMed1994

The three-dimensional structure of Tomes' processes and their relationship to arrangement of enamel prism in dog teeth.

The relationship between the course of enamel prisms and the direction of secretory face in Tomes' process of ameloblast was examined three-dimensionally in the dog tooth by light and electron microscopy, as well as by reconstruction. Scanning electron microscopic observation on the developing enamel surface after the dissolution of the enamel organ showed numerous groups of pits with bulbous faces inclined in the same sidewards direction, while those faces in neighboring groups were inclined in an opposite direction. Tangential semithin sections from demineralized tooth germs were serially cut from the enamel surface to the enamel-dentin junction. These sections showed numerous belt-like zones arranged perpendicular to the meridian of the tooth. A straight row of enamel prisms perpendicular to the boundaries of the belt-like zones was selected at 142 microns from the enamel-dentin junction. The row of prisms and their successive Tomes' processes were reconstructed from micrographs with a personal computer. The cut ends of the enamel prisms initially perpendicular to the boundaries appeared as a sine curve, viewed from the enamel-dentin junction. In a single belt-like zone, the horizontal tilt angles of the enamel prisms towards the enamel-dentin junction tended to be largest at the center of the zone, and smallest near the boundaries. The long axis of each enamel prism was at right angles to the secretory face of the Tomes' process. The secretory faces in a single belt-like zone were inclined in the same sidewards direction and the secretory faces in neighboring zones were inclined in opposite directions. The results suggest that the direction of the sidewards displacement in ameloblasts is related to that of the secretory face of Tomes' processes. Further, one group of ameloblasts with their secretory faces inclined in the same sidewards direction form one belt-like zone.

Ameloblasts↗

PubMed1993

The functional equivalence of demineralized bone and tooth matrices in ectopic bone induction.

The objective of this study was to determine whether demineralized rat incisor matrices were a more potent inducer of ectopic endochondral bone formation than demineralized diaphyseal bone matrices derived from the same donors. Twenty-five-milligram disks of demineralized bone or tooth matrix obtained from adolescent Long-Evans rats were implanted in a standardized ectopic site. Biochemical and histometric measurements of bone formation revealed that the two matrices were functionally equivalent inducers of endochondral bone formation. The induced pellicle of bone reached a maturation point 18 days after implantation. Dentin matrix implants generated a significantly greater amount of mineralized tissue than did bone matrix implants. This difference could be explained on the basis of remineralization of the dentin particles to a greater degree than the bone matrix particles. Initial observations suggesting a more robust osteoinductive activity in demineralized incisor matrix can be attributed to the decreasing activity of bone matrix from older donors when compared to younger donors. The extent of osteoinduction by the two substrata was equivalent when the matrices were matched for age.

Acid Phosphatase↗

PubMed2006

Laser-induced autofluorescence study of caries model in vitro.

Laser-induced autofluorescence spectra of teeth irradiated by a 337 nm nitrogen laser were measured during in vitro caries formation through initial enamel demineralization and introducing of carious bacterial flora in the lesions developed. Spectra obtained from sound teeth consist of an intensive maximum at 480-500 nm and secondary maximum at 430-450 nm. In the process of caries formation, we observed an increase in the intensity at 430-450 nm and the appearance of two maxima in the red spectral region-at 590-650 nm. The intensity increase at 430-450 nm was related to the tooth demineralization. Bacteria presence and their metabolism products induced an increase in the absorption in the UV-blue spectral region at 350-420 nm and the appearance of a fluorescence signal in the long-wave spectral region at 590-650 nm. From the point of view of tissue optics, these results allow caries to be considered as consisting of two different phenomena-tissue destruction and bacterial flora and its metabolism products increase. The results could be used to obtain a more complete picture of caries formation on the base of its fluorescent properties.

Dental Caries↗

PubMed2003

Fluoride varnishes.

Fluoride varnishes are available in the United States, and the Federal Drug Administration has approved a fluoride varnish for use as a cavity preparation lining varnish and as a tooth desensitizing agent. The literature, however, supports the use of fluoride varnishes to inhibit tooth demineralization and enhance remineralization. The purpose of this paper is to present an overview of literature and make recommendations according to the available scientific evidence. Findings support the use of fluoride varnishes as a safe and effective topical fluoride agent.

Cariostatic Agents↗

PubMed1994

Bone formation by marrow osteogenic cells (MBA-15) is not accompanied by osteoclastogenesis and generation of hematopoietic supportive microenvironment.

This study was aimed at elucidating the relationship between osteogenic activity of marrow stromal cells and their ability to support hematopoiesis followed by the bone-remodeling process. We used the MBA-15 cell line, which expresses osteoblastic phenotype in vitro and forms bone in diffusion chamber. We have compared bone formation and hematopoietic responses elicited in vivo by these cells with the implantation of freshly isolated bone marrow cells (BMC) or demineralized tooth matrix (DTM). Both MBA-15 cells and BMC, implanted under the kidney capsule, yielded intramembraneous bone, but DTM, implanted subcutaneously, elicited endochondral bone. MBA-15 formed primary bone, mimicking only the initial sequential stages of the ossification process. Neither histologic signs of bone resorption and remodeling nor tartrate-resistant acid phosphatase (TRAP)-positive cells and marrow formation were observed. Bone formation was monitored biochemically. Functions for hematopoietic stem and committed cell content were measured by GM-CFU and BFU-E assays that confirmed the morphologic observations. In both BMC and DTM implantation, bone formation was followed by hematopoietic activity, osteoclastogenesis, and remodeling. We conclude that MBA-15 osteoprogenitor cells, despite their extensive bone formation ability, are unable to form a microenvironment supportive for hematopoiesis and osteoclastogenesis or to initiate bone remodeling.

Animals↗

PubMed1993

Ability of the hemopoietic microenvironment in the induced bone to maintain the proliferative potential of early hemopoietic precursors.

A comparison of proliferative potential was made between spleen colony forming unit (CFU-S) from skeletal bones and those from ectopically induced ossicles. To this end, mice having two types of ectopic ossicles were used. Each animal was implanted s.c. with demineralized tooth matrix (which served as a source of bone-inducing activity) and again beneath the renal capsule with a femoral bone marrow plug (which was a source of viable osteogenic cells). Those recipient mice that had developed ectopic ossicles were lethally irradiated and then reconstituted with syngeneic bone marrow cells. At various times post-reconstitution, the proliferative potential (PP) of CFU-S in skeletal bones and ectopic ossicles of mice was studied in a double spleen colony test. Hemopoietic cells from each source were injected into lethally irradiated mice; in 11 days, spleen colonies were cut out, and their cells were reinjected into secondary irradiated recipients. The PP of CFU-S was evaluated by examining the development of daughter CFU-S. It was found that, in the hemopoietic microenvironment of induced ossicles, skeletal bone and ectopic ossicles developed by viable osteogenic cells, the PP of CFU-S is maintained to the same extent.

Animals↗

PubMed2001

Evaluation of pH and erosion time on demineralisation.

In the current study the effect of various pH values of citric acid and erosion time on erosion depth and subsurface demineralisation of human enamel was studied. In a laboratory investigation, six groups of 10 samples were eroded in 0.3% citric acid for 2 h at pH 2.54, for 2 h or 4 h at pH 3.2 and for 2 h, 4 h or 8 h at pH 4.5. The erosion depth was measured using a profilometer. The demineralised layer was then removed by ultrasonicating the samples with profilometric measurements taken at 5, 30, 120, 240 and 480 s ultrasonication time. The six test groups were classified by analysis of variance into four homogeneous groups according to their erosion depth and into three homogeneous groups according to their subsurface demineralisation. Erosion depth clearly depended on the pH value of the acid and the contact time. Depth of subsurface demineralisation and surface morphology did not depend on erosion depth. Similar subsurface demineralisation depths can be produced by appropriate combinations of pH and contact time.

Analysis of Variance↗

PubMed2006

Physical properties of root cementum: part 6. A comparative quantitative analysis of the mineral composition of human premolar cementum after the application of orthodontic forces.

INTRODUCTION: The aim of this study was to examine quantitatively with electron probe microanalysis (EPMA) the calcium (Ca), phosphorus (P), and fluoride (F) concentrations in human first premolar cementum after the application of light and heavy orthodontic forces. METHODS: Thirty-six maxillary and mandibular first premolars (18 experimental, 18 control) were extracted from 16 subjects (10 male, 6 female; mean age, 13.9 years; range, 11.7-16.1 years) who were randomly assigned to the light-force or the heavy-force group. In the light-force group, 25 g of buccally directed force was applied to the experimental premolar; in the heavy-force group, 225 g of buccally directed force was applied to the experimental premolar. The contralateral premolar served as the control. The experimental and control premolars were extracted 28 or 29 days after initial force application and prepared for EPMA. The Ca, P, and F concentrations were measured on the buccal and lingual surfaces at the midpoint of the cervical, middle, and apical thirds of the root from the outer to the middle to the inner third of the cementum. RESULTS: Little change was found in the mineral composition of cementum after the application of light forces; however, there was a trend toward an increase in the mineral composition (Ca, P, and F) of cementum at various areas of periodontal ligament compression. The application of heavy forces caused a significant (P = .000) decrease in the Ca concentration of cementum at certain areas of periodontal ligament tension. The application of both light and heavy orthodontic forces did not appear to influence the F concentrations in cementum. CONCLUSIONS: Heavy orthodontic forces cause alterations in the mineral content of cementum; light forces cause little change.

Adolescent↗

PubMed2004

Quantitative analysis of the impact of the organic matrix on the fluoride effect on erosion progression in human dentine using longitudinal microradiography.

After an initial demineralisation, an intensive fluoridation is capable of inhibiting the erosive mineral loss in dentine completely, which might be related to the presence of the exposed organic dentine matrix. Aim of the present study was, therefore, to evaluate whether fluoride is also effective when the organic material is removed. The study was a cyclic de- and remineralisation model over 5 days in vitro. Samples from human coronal dentine were demineralised with citric acid (pH 2.3; 6 x 10 min per day) and intermittently stored in a remineralisation solution. Groups (n = 25 each) were defined as follows: Group 1: erosion only, no fluoridation; Group 2: erosion, alternately fluoridation with toothpaste (NaF; 0.15% F-; 3 x 5 min per day), mouthrinse (Olaflur/SnF2; 0.025 F-; 3 x 5 min per day) and gel (Olaflur/NaF; 1.25% F-; at Days 1 and 3 instead of one toothpaste application); Group 3: erosion and fluoridation as Group 2, organic material was continuously removed with collagenase (from Clostridium Histolyticum type VII, 100 U/ml) added to the remineralisation solution. Mineral content was monitored daily using longitudinal microradiogaphy. After fluoridation in the presence of collagenase, a linear increase in mineral loss (73.3 +/- 17.6 microm at Day 5) was observed, which significantly (P < or = 0.001) exceeded that of the control group (45.9 +/- 14.3 microm at Day 5). After fluoridation in the absence of collagenase, mineral loss ceased after the 2nd day (12.2 +/- 10.2 microm at Day 5) and was significantly lower compared to Groups 1 and 3 (P < or = 0.001). The results indicate that the dentine matrix is essential for the effectiveness of fluoride in dental erosion.

Cariostatic Agents↗

PubMed2006

Effect of an iron mouthrinse on enamel and dentine erosion subjected or not to abrasion: an in situ/ex vivo study.

OBJECTIVES: This in situ/ex vivo study evaluated whether a rinse with an iron solution could reduce wear and the percentage of microhardness change of human enamel and dentine submitted to erosion followed by brushing after 1 or 30min. DESIGN: During 2 experimental 5-day crossover phases (wash-out period of 10 days), 10 volunteers wore intraoral palatal devices, with 12 specimens (6 of enamel and 6 of dentine) arranged in 3 horizontal rows (4 specimens each). In one phase, the volunteers immersed the device for 5min in 150mL of cola drink, 4 times a day. Immediately after immersion, no treatment was performed in one row. The other row was brushed after 1min using a fluoride dentifrice and the device was replaced into mouth. After 30min, the remaining row was brushed. In the other phase, the procedures were repeated, but after immersion the volunteers rinsed for 1min with 10mL of a 10mM ferrous sulphate solution. Changes in surface microhardness (%SMH) and wear (profilometry) of enamel and dentine were measured. Data were tested using ANOVA and Tukey's tests (p<0.05). RESULTS: The enamel presented more wear than dentine, under all experimental conditions. The iron solution caused a significant reduction on the %SMH in enamel, and a significant reduction on the wear in dentine, regardless the other conditions. CONCLUSIONS: Rinsing with an iron solution after an erosive attack, followed or not by an abrasive episode, may be a viable alternative to reduce the loss of dental structure.

Adult↗