Post-Pleistocene changes in the human dentition.
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Anthropology, Cultural↗
SEARCH · PubMed Health
Results for “Tooth erosion”
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Interstitial wear.
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Adaptation, Biological↗
Canine role in dental wear patterns: Macaca nemestrina.
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Age Factors↗
Functional implications of primate enamel thickness.
Recent evolutionary interpretations of Hominoidea have postulated functional relationships between tooth form, diet and masticatory biomechanics. A major consideration is the durability of the tooth under certain dietary conditions. Teeth with low cusps and thicker enamel are able to withstand heavy mastication of abrasive food bolus for a longer period. When comparisons are made between species of higher primates the variables of tooth size, cusp morphology, and enamel thickness appear to be related but until now no systematic analysis has been made to determine the functional relevance of several dental dimensions. This study provides data gained from comparisons of dentition of nine species of primates. Histological sections were made of the post canine teeth and 21 dimensions were compared. The relevant dimensions identified serve to withstand dental wear. The distribution of thicker enamel corresponded to the observed wear planes. Humans had thicker enamel than pongids while the macaque had the thinnest. These preliminary results tend to support theories which explain low, thick, enameled cusps in hominids.
Animals↗
Selective pressures and dental evolution in hominids.
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Biological Evolution↗
Tooth wear in Australian aboriginal populations from the River Murray Valley.
The study of tooth wear among prehistoric and recent populations has frequently been concerned with the rate and pattern of wear over the dental arches. In this report we considered the question of tooth wear variation among collections of Australian Aboriginal crania recovered from several sites along the Murray River in Southeastern Australia. These crania represent the remains of relatively recent populations from about 2,000 years ago until the early 19th century. The degree of tooth wear for each dental arch was recorded by an established method of determining the ratio of exposed dentin. The pattern or distribution of wear over each arch was summarized by principal component analysis. The mean wear degree and pattern were compared among four geographical grouping of crania separated by up to 700 miles of river frontage. Our results showed, as expected, a significant difference between the well-defined population at the Lower Murray site (Swanport) and the three upriver groups. However, there were significant differences among these three collections as well. Sexual dimorphism was noted but was only significant in the Lower Murray group; the mean wear was greater and also more variable among the males. At the second of the Middle Murray sites the pattern of wear was different and the degree of wear was significantly less than in the other groups. A possible explanation for this diversity may be environmental and subsistence base differences. The evidence from the Lower Murray supports this possibility, but the differences among the other three groups are not as clearly established. However, our results do suggest that the Murray Black collection, from which these crania were obtained, may not be as homogeneous a group as previously believed.
Australia↗
Influence of soft drinks on the thickness and morphology of in situ acquired pellicle layer on enamel.
Diet-induced demineralization is a key factor in tooth enamel loss, with soft drinks being a significant aetiological agent. In the oral environment, the acquired pellicle layer might modify the demineralization potential of drinks. The objectives of this exploratory in situ study were to determine the influence of soft drinks, volunteers, and exposure times on the thickness and morphology of pellicle layers using an atomic force microscope (AFM). Polished uninterrupted third molars were partly taped and exposed to the oral environment for periods of 2 and 5 days, respectively. Each day 1L of either mineral water, a "toothkind" blackcurrant drink, a "prototype" blackcurrant drink, or orange juice was consumed in this four-way crossover, single-center study. Subsequently the tape was removed and the surfaces imaged with an AFM before and after chemical cleaning. The pellicle layer morphology and thickness were investigated. The maximum pellicle layer thickness was observed after the consumption of the prototype blackcurrant drink, followed by the toothkind blackcurrant drink, orange juice, and water on days 2 and 5, respectively. A three-way ANOVA at the 95% confidence level showed statistically significant differences between the pellicle layer thicknesses, factors being drinks (p=0.0046), exposure time (p=0.0009), and volunteers (p=0.0244). Depending on the volunteer either a uniform or a patchy pellicle layer was observed. This demonstrates that AFM is a useful tool in obtaining simultaneously qualitative and quantitative data of in situ acquired pellicle layers.
Beverages↗
Oxygen metabolism, oxidative stress and acid-base physiology of dental plaque biofilms.
Dental plaque is a natural biofilm which has been a focus of attention for many years because of its known roles in caries and periodontal diseases. Acid production by plaque bacteria leads to the erosion of tooth mineral in caries, and the cariogenicity of plaque is related to population levels of acid-tolerant organisms such as mutans streptococci. However, the biofilm character of plaque allows for survival of a diverse flora, including less acid-tolerant organisms, some of which can produce ammonia from arginine or urea to counter acidification. Plaque is often considered to be relatively anaerobic. However, evidence is presented here that both supragingival and subgingival plaque have active oxygen metabolism and that plaque bacteria, including anaerobes, have developed defenses against oxidative stress. Even in subgingival plaque associated with periodontitis, measured residual oxygen levels are sufficient to allow for oxygen metabolism by organisms considered to be extremely anaerobic such as Treponema denticola, which metabolizes oxygen by means of NADH oxidases and produces the protective enzymes superoxide dismutase and NADH peroxidase. The finding that plaque bacteria produce a variety of protective enzymes is a good indicator that oxidative stress is a part of their everyday life. The biofilm character of plaque allows for population diversity and coexistence of aerobes, anaerobes and microaerophiles. Overall, agents that affect oxidative metabolism offer possibilities for reducing the pathogenic activities of plaque.
Acid-Base Equilibrium↗
Tooth surface loss: does recreational drug use contribute?
OBJECTIVE: This pilot study was designed to measure tooth wear in a sample of 13 subjects who regularly use amphetamine-like drugs (Ecstasy, amphetamines) and compare the observed wear with a matched sample of nondrug users. DESIGN: The two groups, both composed of 13 undergraduate students, were matched for age and sex. Other factors influencing tooth wear were controlled by matching the groups on their responses to a questionnaire asking about recognised common causes of tooth wear. The participants teeth were examined and the degree of wear scored according to a tooth wear index. RESULTS: Severity of occlusal tooth wear of the lower first molar teeth was significantly greater in the drug user group than in the control group (P<0.05). No other statistically significant differences between the groups were found. CONCLUSION: Regular use of amphetamine-like drugs could be associated with increased posterior tooth wear.
Adolescent↗
Influence of salivary pellicle formation time on enamel demineralization--an in situ pilot study.
This study assessed the protective potential of salivary pellicles formed in situ over periods ranging from 2 to 24 h. Pellicles were produced on enamel slabs mounted on the palatal aspect of removable acrylic splints and exposed to the oral environment in three subjects for 2, 6, 12 and 24 h. Enamel specimens with and without pellicles were immersed in citric acid (1%) for 60 s, and the amount of dissolved calcium was measured by atomic absorption spectroscopy. In addition, specimens were processed for transmission electron microscopy (TEM). Mean values (standard deviations) for calcium release (mg/l related to the specimen's surface area of 5 x 5 mm(2)) were: 2-h pellicle 6.94 (1.55); 6-h pellicle 6.69 (2.05); 12-h pellicle 6.57 (2.31); 24-h pellicle 5.71 (2.46); enamel without pellicle 8.95 (1.66). There were no significant differences in calcium release that were dependent on pellicle formation time, but in comparison to enamel specimens without pellicle, significantly less (p <0.05) demineralization of the enamel was observed in pellicle-covered specimens. TEM showed that the pellicle was partly, but not completely dissolved following acid exposure. It is concluded that even a 2-h in-situ-formed pellicle layer protects the enamel surface to a certain extent against demineralization.
Analysis of Variance↗
Class V lesions restored with four different tooth-colored materials--3-year results.
The aim of this study was to compare the treatment results using four different types of tooth colored materials for restoring class V lesions. A total of 197 class V restorations (n = 197) were placed by one dentist in 37 patients on incisors, canines and premolars. The fillings were placed due to different indications: erosion/non-carious cervical defects (n = 69), primary carious lesions (n = 57), and for replacing defective existing fillings (n = 71). The teeth were assigned on a random basis to four groups for restoration with either a composite (group 1: n = 36; Tetric, Vivadent), or a polyacid-modified resin composite (group 2: n = 79; Dyract, Dentsply), or one of two different resin-modified glass ionomer cements (group 3: n = 51, Fuji II LC,GC; group 4: n = 31, Photac-Fil, Espe). The restorations were evaluated by a single-blind design, according to a modified USPHS system 36 months following placement. Statistical analysis was completed with the Pearson Chi-square test for comparing the results of the four groups (P < 0.05). Additionally, the survival rates were analyzed with the Kaplan-Meier estimator and the Log-rank test (P < 0.05). The Alpha ratings were as follows (Tetric/Dyract/Fuji II LC/Photac Fil): shade match (86%/77%/58%/40%), surface texture (81%/83%/16%/9%), marginal integrity (enamel) (73%/67%/61%/61%), marginal integrity (dentin) (86%/70%/55%/61%), marginal discoloration (enamel) (59%/44%/58%/52%), marginal discoloration (dentin) (82%/84%/71%/48%), anatomic contours (91%/83%/39%/35%). One Tetric restoration, five Dyract restorations, two Fuji II LC restorations and three Photac restorations were dislodged within the study period. The retention of the restorations showed no significant difference among the four materials. However, the clinical performance of the restorations retained over the 3-year period showed distinct differences for the four materials. The best clinical performance was observed for the resin composite, whereas the quality of the Dyract restorations without enamel etching was worse. The poorest results were obtained for the restorations with the resin-modified glass ionomers.
Adult↗
Raman spectroscopic study of noncarious cervical lesions.
The surface of noncarious cervical lesions (NCCLs) consists of sclerosed dentin. This type of dentin may affect the ability of adhesive restorative materials to bond well to its surface, but little information exists on the chemical nature of this dentin surface and how it may be affected during acidic treatment. The inorganic part of normal dentin and dentin from NCCLs before and after acid conditioning with phosphoric acid or polyacrylic acid was investigated. Ten premolars with NCCLs and four human third molars (control) were used. Replicas of NCCLs were examined using scanning electron microscopy (SEM). Surfaces and longitudinal sections of four NCCLs and control dentin discs were analyzed using Raman spectroscopy. The discs and NCCLs were sectioned, and treated with 35% phosphoric acid or 20% polyacrylic acid/3% aluminum chloride, and Raman spectra obtained. The area under phosphate nu1 of the dentin spectrum was computed to obtain a ratio with the area under the second-order spectrum of a silicon phonon comparative standard. Mean phosphate nu1 and silicon phonon ratios from normal dentin and NCCLs were compared using a linear model with repeated measurements and Tukey's pairwise tests. Mean ratios from different locations of the NCCLs were compared using one-way analysis of variance (ANOVA) and Tukey's pairwise tests. SEM micrographs of NCCL surfaces showed variation from relatively smooth with no dentinal tubule openings to surfaces with occluded tubules. The mean phosphate nu1 and silicon phonon ratios for NCCLs were higher than those of normal dentin in all treatment groups (P < 0.05). Ratios from the untreated specimens were higher than those of the polyacrylic acid-treated specimens, and those for the phosphoric acid-treated group were the lowest (P < 0.05). The ratios obtained for the surfaces of NCCLs were higher than those halfway towards the pulp, and those adjacent to the pulp were the lowest (P < 0.05).
Acid Etching, Dental↗
Diagnosis and management of supra-esophageal complications of reflux disease.
Supra-esophageal reflux disease may be manifested in numerous ways, including reflux laryngitis, chronic cough, chronic sinusitis, and dental enamel loss. The mechanisms of pharyngeal and laryngeal reflux are not clearly defined, and standard reflux testing does not consistently demonstrate supra-esophageal reflux. The diagnosis is usually based on clinical suspicion when other causes of symptoms are not found and on the patient's response to empiric acid suppression. With the development of triple-probe pH monitoring, through which pharyngeal pH can be assessed along with esophageal pH, the physician may now be able to demonstrate pharyngeal reflux in relation to patient symptoms. Therapy consists primarily of behavioral modification and aggressive acid suppression, although some alternative therapies exist.
Algorithms↗
Enamel loss during orthodontic bonding and subsequent loss during removal of filled and unfilled adhesives.
1. The techniques required in the removal of highly filled composite adhesives at the end of orthodontic treatment on an average cause more loss of enamel than removal of an unfilled polymethylmethacrylate adhesive. 2. The amount of enamel lost during the removal of either adhesive may be of clinical significance because of the removal of a major part of the protective fluoride-rich layer of enamel. 3. The use of zirconium silicate on a rotating bristle brush may cause considerable abrasion of enamel.
Acid Etching, Dental↗
Enamel loss due to orthodontic bonding with filled and unfilled resins using various clean-up techniques.
An in vitro study using steel reference markers in the enamel of 100 premolars was carried out in order to determine the enamel loss resulting from each step in the placement and removal of bonded orthodontic attachments. Measurements were made by means of the optical system of a profile projector for orientation and positioning and a micrometer for quantification. Accuracy to within +/- 1 micron was achieved. The 10.7 micron of enamel lost during initial prophylaxis with bristle brush was greater than the 5.0 micron lost when a rubber cup was used, and the difference was statistically significant. A 90-second etch with phosphoric acid resulted in a mean loss of 6.9 micron, with no significant difference between liquid and gel forms. It was possible to clean up the unfilled resin with hand instruments only; this resulted in a mean enamel loss of 7.7 micron. Rotary instruments, however, were required for cleaning up filled resin. Within this group, more enamel was lost when the high-speed 7902 bur (19.2 micron) and green rubber wheel (18.4 micron) were used than when the low-speed 7111 bur (11.3 micron) was used. Total enamel loss ranged from 26.1 to 31.8 micron for unfilled resin and from 29.5 to 41.2 micron for filled resin, depending on the instrument used for prophylaxis and debonding. Twenty-seven of the teeth showed evidence of a perikymata-like structure after as much as 29 micron of enamel had been removed, questioning the reliability of anatomic landmarks as reference points in the study of enamel loss.
Acid Etching, Dental↗
Post-mortem changes in human teeth from late upper palaeolithic/mesolithic occupants of English limestone cave.
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Dental Caries↗
Tooth wear, solubility and fluoride concentration of molar-tooth surfaces in rats maintained on simultaneous or separate intake of food and fluoridated drinking water.
Eighty rats, 20 days old, were fed a hard pellet diet and deionized or fluoridated (25 parts/10(6) F-) drinking water respectively for 40 days. Half were maintained on simultaneous food and water intake for 3 h, daily, and the remainder on separate intake of food for 3 h followed by drinking water for 3 h, daily. Scanning electron micrographs of the occlusal surface of right maxillary first molars were used for scoring wear. The mandibular and left maxillary molar surfaces were used for solubility and fluoride concentration determinations. Intake of food and water separately did not affect wear significantly, whereas solubility and fluoride concentration of the molar surfaces were significantly increased. Wear, solubility and fluoride of the molar surfaces respectively were highly significantly increased in the rats provided with fluoridated water. Increase in fluoride uptake is due in part at least to the increase in sites available for uptake due to tooth wear. Acid dissolution of worn tooth-surface enamel is greater than that of intact enamel.
Animals↗
Cariogenic effect of caffeine intake during lactation on first molars of newborn rats.
Lactating dams with eight suckling pups were fed either a 20% protein diet as a control or experimentally a 20% protein diet supplemented with caffeine (2 mg/100g body weight) from the birth of the pups to day 22. At day 22, the pups from both groups were weaned and fed a cariogenic diet until day 50, when they were killed. Dental caries of the molars were scored from randomized mandibles. The enamel of the first molars in the caffeine group showed significantly higher caries scores than that of the controls. This appears to be the first unequivocal evidence that caffeine is a cariogenic agent when newborns are exposed to it during critical periods of tooth development. Therefore, the widespread human consumption of caffeine could be a threat to the healthy development of teeth.
Animals↗