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Wear Facets (wear + facet)

Distribution by Scientific Domains

Medical Sciences	70%

Selected Abstracts

Prevalence and side preference for tooth grinding in twins

AUSTRALIAN DENTAL JOURNAL, Issue 3 2006
KV Dooland
Abstract Background: Estimates of the prevalence of tooth grinding in children range considerably, reflecting different methods of recording. The main aims of this study were to determine the prevalence of tooth grinding in monozygotic (MZ) and dizygotic (DZ) twin pairs by assessing wear faceting on the primary canines, and to compare the faceting on the right and left to determine whether children have a side preference for grinding. Methods: The sample consisted of 116 MZ twin pairs and 124 dizygous DZ twin pairs, all participants in an ongoing study of dento-facial development at the dental schools in Adelaide and Melbourne. Evidence of wear faceting on primary maxillary and mandibular canine tips was recorded from dental casts, and the side with the larger wear facet recorded. Types of occlusal relationship, handedness, zygosity and gender were also recorded, and associations between variables analysed statistically. Results: Canine tip wear facets were found in 100 per cent of the sample, and grinding was lateralized in 59 per cent of children. MZ twin pairs showed a higher discordance for grinding side preference than DZ twin pairs (33.8 per cent compared with 16.8 per cent), providing evidence of a mirror-imaging effect for grinding side preference. There was no strong evidence that individuals had the same preference for grinding side and handedness, although right-handers (RH) showed a preference for a grinding side more often than non-righthanders (NRH) (63.6 per cent compared with 51.2 per cent), consistent with previous findings that RHs display more cerebral lateralization than NRHs. Conclusions: Tooth grinding appears to be a universal phenomenon in children and is commonly expressed more on one side than the other. The significantly higher discordance for grinding side preference in MZ twin pairs compared with DZ twin pairs may reflect a mirror-imaging effect in the former. However, at present we have no evidence to suggest that handedness and preferred tooth grinding side are associated. [source]

Prevalence of Noncarious Cervical Lesions and Their Relation to Occlusal Aspects: A Clinical Study

JOURNAL OF ESTHETIC AND RESTORATIVE DENTISTRY, Issue 1 2000
DANIEL TELLES DDS
ABSTRACT Purpose: The purpose of this study was to assess noncarious cervical lesions in young patients and to establish a possible relation with occlusal aspects. Materials and Methods: Forty-eight dental students (28 males; 20 females) between the ages of 16 and 24 years, were investigated to verify the presence of noncarious cervical lesions and their relation to some occlusal aspects. The assessment involved a questionnaire, clinical examinations, and model analysis. Results: The results indicated that the lower first molars (21.3%), the upper first molars (16.0%), the upper first premolars (12.8%), the lower first premolars (11.7%), and the lower second premolars (11.7%) were the teeth most affected by the lesions. Age was a significant factor with respect to the presence of lesions; the students with noncarious cervical lesions were older than the students who showed no lesions. Among the 79 teeth exhibiting lesions, 62 (78.5%) showed wear facets. In the group with lesions, the mean, per subject, was 15.0 teeth with wear facets, whereas in the group without lesions the mean was 10.8 teeth with wear facets per subject, suggesting that occlusal stress has some effect on lesion development. CLINICAL SIGNIFICANCE Noncarious cervical lesions are characterized by loss of tooth structure on the cervical area of the tooth and can result in esthetic problems for the patient, as well as discomfort due to the hyper-sensibility that often occurs at the location of the lesion. The results obtained reinforce the multifactorial theory, shared by several authors, for the etiology of such lesions. However, as the limitations of each etiologic agent begin to be understood, there will be a decrease in the possibility of misleading interpretations of the result of present or future investigations. [source]

Effect of conditioning electrical stimuli on temporalis electromyographic activity during sleep

JOURNAL OF ORAL REHABILITATION, Issue 3 2008
F. JADIDI
Summary, Inhibitory reflexes during voluntary contractions are well described; however, few studies have attempted to use such reflex-mechanisms to modulate electromyographic (EMG) activity in jaw-closing muscles during sleep. The aim was to apply a new intelligent biofeedback device (Grindcare®) using electrical pulses to inhibit EMG activity in the temporalis muscle during sleep. Fourteen volunteers participated who were aware of jaw-clenching activity as indicated by complaints from sleep partner, soreness or pain in the jaw-muscle upon awakening and tooth wear facets. The EMG activity was recorded from the temporalis muscle, online analysed and the frequency content determined using a signal recognition algorithm. Based on specific individual parameters for pattern recognition, an electrical square-wave pulse train, which was adjusted to a clear, but non-painful intensity (range 1,7 mA) was applied through the EMG electrodes, if jaw-clenching activity was detected. All volunteers had baseline EMG recordings for five to seven consecutive nights, followed by 3-weeks EMG recordings with the feedback turned on, 2 weeks without the feedback and finally 3 weeks with the biofeedback on. There were no session effects on the average duration of sleep hours (P = 0·626). The number of EMG episodes/hour sleep was significantly reduced during the two sessions with biofeedback (54 ± 14%; 55 ± 17%, P < 0·001) compared with baseline EMG activity and the session without biofeedback. The present study suggests that biofeedback with electrical pulses does not cause major disruption in sleep and is associated with pronounced reduction in temporalis EMG activity during sleep. [source]

Confocal Examination of Subsurface Cracking in Ceramic Materials

JOURNAL OF PROSTHODONTICS, Issue 7 2009
MMedSc, Maged K. Etman DDS
Abstract Purpose: The original ceramic surface finish and its microstructure may have an effect on crack propagation. The purpose of this study was to investigate the relation between crack propagation and ceramic microstructure following cyclic fatigue loading, and to qualitatively evaluate and quantitatively measure the surface and subsurface crack depths of three types of ceramic restorations with different microstructures using a Confocal Laser Scanning Microscope (CLSM) and Scanning Electron Microscope (SEM). Materials and Methods: Twenty (8 × 4 × 2 mm3) blocks of AllCeram (AC), experimental ceramic (EC, IPS e.max Press), and Sensation SL (SSL) were prepared, ten glazed and ten polished of each material. Sixty antagonist enamel specimens were made from the labial surfaces of permanent incisors. The ceramic abraders were attached to a wear machine, so that each enamel specimen presented at 45 degrees to the vertical movement of the abraders, and immersed in artificial saliva. Wear was induced for 80K cycles at 60 cycles/min with a load of 40 N and 2-mm horizontal deflection. The specimens were examined for cracks at baseline, 5K, 10K, 20K, 40K, and 80K cycles. Results: Twenty- to 30-,m deep subsurface cracking appeared in SSL, with 8 to 10 ,m in AC, and 7 ,m close to the margin of the wear facets in glazed EC after 5K cycles. The EC showed no cracks with increasing wear cycles. Seventy-,m deep subsurface cracks were detected in SSL and 45 ,m in AC after 80K cycles. Statistically, there was significant difference among the three materials (p < 0.05). Bonferroni multiple comparison of means test confirmed the ANOVA test and showed that there was no statistical difference (p > 0.05) in crack depth within the same ceramic material with different surface finishes. Conclusions: The ceramic materials with different microstructures showed different patterns of subsurface cracking. [source]

Brief communication: Identification reassessment of the isolated tooth Krapina D58 through occlusal fingerprint analysis

AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 2 2010
Luca Fiorenza
Abstract High variability in the dentition of Homo can create uncertainties in the correct identification of isolated teeth. For instance, standard tooth identification criteria cannot determine with absolute certainty if an isolated tooth is a second or third maxillary molar. In this contribution, using occlusal fingerprint analysis, we reassess the identification of Krapina D58 (Homo neanderthalensis), which is catalogued as a third maxillary molar. We have hypothesized that the presence/absence of the distal occlusal wear facets can be used to differentiate second from third maxillary molars. The results obtained confirm our hypothesis, showing a significant difference between second and third maxillary molars. In particular we note the complete absence of Facets 7 and 10 in all third molars included in this analysis. The presence of these facets in Krapina D58 eliminates the possibility that it is a third maxillary molar. Consequently it should be reclassified as a second molar. Although this method is limited by the degree of dental wear (i.e., unworn teeth cannot be analyzed) and to individual molars in full occlusion, it can be used for tooth identification when other common criteria are not sufficient to discriminate between second and third maxillary molars. Am J Phys Anthropol 143:306,312, 2010. © 2010 Wiley-Liss, Inc. [source]

Diet reconstruction in antebellum Baltimore: Insights from dental microwear analysis

AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 4 2010
Peter H. Ma
Abstract Construction in the City of Baltimore during 1996 led to the recovery of human skeletal remains dating from 1792 to 1856. Historical research indicates that the skeletal remains come from two adjacent graveyards: Christ's Church Episcopalian Cemetery and the Potters Field East. The different socioeconomic status of the internees in each cemetery suggests the possibility of marked contrasts in lifestyle, health, and diet. To shed further light on these possibilities, analyses of microscopic wear patterns on teeth, or dental microwear analyses, were undertaken. A sample from Spanish Florida was used to help interpret the results. Epoxy casts of incisor and molar teeth were placed in an SEM and photomicrographs of clean wear facets were taken. The photomicrographs were digitized using the software package Microware 4.02. Statistical analyses of rank transformed data consisted of single-factor ANOVA, followed by post hoc tests. No significant differences were found between Christ's Church and Potters Field East samples for any of the variables examined in either molar or incisor teeth. However, differences between each Baltimore sample and the La Florida samples give suggestions of possible diet differences in antebellum Baltimore. The mosaic of differences between the Baltimore and La Florida samples probably reflects the wide variety of foods available to antebellum Baltimoreans as well as the relative lack of abrasives in their diet. Am J Phys Anthropol, 2010. © 2009 Wiley-Liss, Inc. [source]

Technical note: Occlusal fingerprint analysis: Quantification of tooth wear pattern

AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 4 2009
Ottmar Kullmer
Abstract Information about food ingestion and mastication behavior during the lifespan of an individual is encoded in the dental occlusal wear pattern. To decode this information, we describe a new method called occlusal fingerprint analysis (OFA). Structural parameters of wear facets on the occlusal surface of teeth are quantified from digitized casts for the interpretation of occlusal aspects. The OFA provides an individual three-dimensional dental occlusal compass that indicates the major pathways of interaction between antagonists, revealing information about development, spatial position, and enlargement of wear facets. Humans develop a very similar overall pattern of crown contacts, although specific characteristics of wear facets reflect an individual's occlusal relationships and masticatory behavior. We hypothesize that the wear pattern is a unique character and therefore valuable for individual identification. Furthermore we suggest that OFA, when further developed, may be useful for identification of behavioral, biological, and chemical factors affecting crown morphology. Am J Phys Anthropol, 2009. © 2009 Wiley-Liss, Inc. [source]

The effect of casein phosphopeptide-amorphous calcium phosphate on erosive dentine wear

AUSTRALIAN DENTAL JOURNAL, Issue 2 2009
S Ranjitkar
Abstract Background:, Erosive tooth wear is a growing concern in clinical dentistry. Our aims were to assess the effect of Tooth Mousse (TM) in managing erosive dentine wear in vitro. Methods:, Opposing enamel and dentine specimens from 36 third molar teeth were worn under a load of 100 N for 75 000 cycles in electromechanical tooth wear machines. In experiment 1, TM was applied continuously at the wear interface and the mean dentine wear rate was compared with those of specimens subjected to continuous application of hydrochloric acid (HCl, pH 3.0) and deionized water (DW, pH 6.1) as lubricants. In experiment 2, specimens were subjected to TM application every 1600 cycles at both pH 3.0 and 6.1, and the mean dentine wear rates were compared with those of specimens worn with continuous application of HCl and DW lubricants. Results:, Dentine wear was reduced significantly with continuous application of TM compared with HCl and DW lubricants. Specimens prepared with continuous TM application displayed smooth wear facets, whereas more pronounced microwear details were observed with HCl and DW lubricants. Conclusions:, Both remineralization and lubrication seem to contribute to reduction in dentine wear associated with TM application, although lubrication appears to have a more pronounced effect. [source]

Abfraction: separating fact from fiction

AUSTRALIAN DENTAL JOURNAL, Issue 1 2009
JA Michael
Abstract Non-carious cervical lesions involve loss of hard tissue and, in some instances, restorative material at the cervical third of the crown and subjacent root surface, through processes unrelated to caries. These non-carious processes may include abrasion, corrosion and possibly abfraction, acting alone or in combination. Abfraction is thought to take place when excessive cyclic, non-axial tooth loading leads to cusp flexure and stress concentration in the vulnerable cervical region of teeth. Such stress is then believed to directly or indirectly contribute to the loss of cervical tooth substance. This article critically reviews the literature for and against the concept of abfraction. Although there is theoretical evidence in support of abfraction, predominantly from finite element analysis studies, caution is advised when interpreting results of these studies because of their limitations. In fact, there is only a small amount of experimental evidence for abfraction. Clinical studies have shown associations between abfraction lesions, bruxism and occlusal factors, such as premature contacts and wear facets, but these investigations do not confirm causal relationships. Importantly, abfraction lesions have not been reported in pre-contemporary populations. It is important that oral health professionals understand that abfraction is still a theoretical concept, as it is not backed up by appropriate clinical evidence. It is recommended that destructive, irreversible treatments aimed at treating so-called abfraction lesions, such as occlusal adjustment, be avoided. [source]