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Tooth wear has an increasing prevalence in the UK population. The aetiology is commonly multifactorial, and the aetiopathology is through a combination of erosion, attrition, abrasion and abfraction. Erosion is associated with intrinsic or extrinsic acids, and therefore subjects with reflux disease and eating disorders are at increased risk. Fruit juice, fruits and carbonated drink consumption, frequency of consumption and specific habits are also risk factors. Attrition is more prevalent in bruxists. Other habits need to be considered when defining the risk of tooth wear. Abrasion is usually associated with toothbrushing and toothpastes, especially in an already acidic environment. Patients with extensive lesions that affect dentin may be at higher risk, as well as those presenting with unstained lesions. Monitoring of the progress of tooth wear is recommended to identify those with active tooth wear. Indices for tooth wear are a helpful aid.

The incidence of toothwear in the population is increasing, as is the number of referrals regarding this problem to secondary care dental hospital consultants and specialists. This paper outlines current theories in aetiology, diagnosis and management of localized and generalized toothwear, as well as describing clinical tips for assessing such patients.

Study Objectives: To estimate the frequency of obstructive sleep apnea syndrome (OSAS) in dental patients with tooth wear, and to assess the role of dentists in the identification of patients at risk of OSAS., Methods: Dental patients with tooth wear and treated with occlusal splint were prospectively recruited to perform sleep study. The severity of tooth wear was established by the treating dentist before patient referral to sleep disorders unit. Sleep questionnaires, anthropometric measurements, and validated respiratory polygraphy were performed., Results: All patients with dental wear were offered a sleepiness analysis. Of 31 recruited patients, 30 (77% males) participated in this study. Patients' mean age was 58.5 ± 10.7 years (range: 35-90 years) and the body mass index was 27.9 ± 3.4 kg/m(2). Tooth wear was mild in 13 patients, moderate in 8 and severe in 9. The mean apnea-hypopnea index (AHI) was 32.4 ± 24.9. AHI < 5 was reported in 2 patients, AHI of 5-29 in 17, and AHI ≥ 30 in 11. A statistically significant association was found between AHI severity and tooth wear severity (Spearman R = 0.505; p = 0.004)., Conclusions: Tooth wear could be a tool to identify those patients at risk of having OSAS. This highlights the importance of dental professionals to identify and refer patients with OSAS., (© 2015 American Academy of Sleep Medicine.)

Background and Aims: The scope of this working group was to review: (1) the effect of professional mechanical plaque removal (PMPR) on secondary prevention of periodontitis; (2) the occurrence of gingival recessions and non-carious cervical lesions (NCCL) secondary to traumatic tooth brushing; (3) the management of hypersensitivity, through professionally and self administered agents and (4) the management of oral malodour, through mechanical and/or chemical agents., Results and Conclusions: Patients undergoing supportive periodontal therapy including PMPR showed mean tooth loss rates of 0.15 ± 0.14 teeth/year for 5-year follow-up and 0.09 ± 0.08 teeth/year (corresponding to a mean number of teeth lost ranging between 1.1 and 1.3) for 12-14 year follow-up. There is no direct evidence to confirm tooth brushing as the sole factor causing gingival recession or NCCLs. Similarly, there is no conclusive evidence from intervention studies regarding the impact of manual versus powered toothbrushes on development of gingival recession or NCCLs, or on the treatment of gingival recessions. Local and patient-related factors can be highly relevant in the development and progression of these lesions. Two modes of action are used in the treatment of dentine hypersensitivity: dentine tubule occlusion and/or modification or blocking of pulpal nerve response. Dentifrices containing arginine, calcium sodium phosphosilicate, stannous fluoride and strontium have shown an effect on pain reduction. Similarly, professionally applied prophylaxis pastes containing arginine and calcium sodium phosphosilicate have shown efficacy. There is currently evidence from short-term studies that tongue cleaning has an effect in reducing intra-oral halitosis caused by tongue coating. Similarly, mouthrinses and dentifrices with active ingredients based on Chlorhexidine, Cetylpyridinium chloride and Zinc combinations have a significant beneficial effect., (© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Aim: To identify the best available evidence for the effect of toothbrushing on the initiation and progression of gingival recession and non-carious cervical lesions (NCCLs)., Methods: A protocol was developed for the questions: Does traumatic toothbrushing, compared to normal toothbrushing, lead to an increased prevalence of non-inflammatory gingival recession? [FQ1] and NCCLs? [FQ2]. The search covered four electronic databases. Bibliographies of review articles, relevant texts, World and European Workshops were screened. Hand searches were performed of the Journals of Clinical Periodontology, Periodontology, Periodontal Research and IADR abstracts., Results: A meta-analysis included 159 subjects and showed that subjects who used MTBs (manual toothbrush) had greater gingival recession after 12 months when compared with those using PTBs (powered toothbrush). Thirteen cross-sectional studies identified the most frequent toothbrushing factors associated with gingival recession as being toothbrushing frequency, a horizontal or scrub toothbrushing method, bristle hardness, toothbrushing duration and the frequency of changing a toothbrush. The principal toothbrushing factors associated with NCCLs were toothbrushing method and frequency., Conclusion: The data to support or refute the association between toothbrushing and gingival recession and NCCLs remain largely inconclusive., (© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

The purpose of this study was to determine the prevalence and possible etiological factors of erosive tooth wear and wedge-shaped defects in Swiss Army recruits and compare the findings with those of an analogous study conducted in 1996. In 2006, 621 recruits between 18 and 25 years of age (1996: 417 recruits; ages 19 to 25) were examined for erosive tooth wear and wedge-shaped defects. Additional data was acquired using a questionnaire about personal details, education, dentition’s subjective condition, oral hygiene, eating and drinking habits, medications used, and general medical problems. In 2006, 60.1% of those examined exhibited occlusal erosive tooth wear not involving the dentin (1996: 82.0%) and 23.0% involving the dentin (1996: 30.7%). Vestibular erosive tooth wear without dentin involvement was seen in 7.7% in 2006 vs. 14.4% in 1996. Vestibular erosive tooth wear with dentin involvement was rare in both years (0.5%). Oral erosive tooth wear lacking exposed dentin was also rare in those years, although more teeth were affected in 2006 (2.1%) than in 1996 (0.7%). The examinations in 2006 found one or more initial wedge-shaped lesions in 8.5% of the recruits, while 20.4% of the study participants exhibited such in 1996. In 1996, 53% consumed acidic foods and beverages more than 5 times/day; in 2006, 83.9% did so. In neither study did multivariate regression analyses show any significant correlations between occurrence and location of erosive tooth wear and wedge-shaped defects and various other parameters, e.g., eating and hygiene habits, or dentin hyper-sensitivity. Despite a significant increase in consumption of acidic products between 1996 and 2006, the latter study found both fewer erosive tooth wear and fewer wedge-shaped defects (i.e., fewer non-carious lesions.).

Objective: This paper describes the development and standardization of a profilometry-based method for assessment of dentifrice abrasivity called Radioactive Dentin Abrasivity - Profilometry Equivalent (RDA-PE)., Methods: Human dentine substrates are mounted in acrylic blocks of precise standardized dimensions, permitting mounting and brushing in V8 brushing machines. Dentin blocks are masked to create an area of "contact brushing." Brushing is carried out in V8 brushing machines and dentifrices are tested as slurries. An abrasive standard is prepared by diluting the ISO 11609 abrasivity reference calcium pyrophosphate abrasive into carboxymethyl cellulose/glycerin, just as in the RDA method. Following brushing, masked areas are removed and profilometric analysis is carried out on treated specimens. Assessments of average abrasion depth (contact or optical profilometry) are made., Results: Inclusion of standard calcium pyrophosphate abrasive permits a direct RDA equivalent assessment of abrasion, which is characterized with profilometry as Depth test/Depth control x 100. Within the test, the maximum abrasivity standard of 250 can be created in situ simply by including a treatment group of standard abrasive with 2.5x number of brushing strokes. RDA-PE is enabled in large part by the availability of easy-to-use and well-standardized modern profilometers, but its use in V8 brushing machines is enabled by the unique specific conditions described herein., Conclusion: RDA-PE permits the evaluation of dentifrice abrasivity to dentin without the requirement of irradiated teeth and infrastructure for handling them. In direct comparisons, the RDA-PE method provides dentifrice abrasivity assessments comparable to the gold industry standard RDA technique.

This study aimed to investigate the association between dental erosive wear and potential background, behavioural and dietary risk indicators and to assess whether there is a dose-response relationship between the level of acidic beverage consumption and dental erosive wear among adolescents. Of 846 adolescents (aged 16-18 years) scheduled for dental recall examinations, 795 (94%) accepted to participate. All participants completed a self-administered questionnaire regarding their background (gender and age), tooth-brushing frequency and dietary habits (the amount and frequency of acidic food and beverage consumption as well as the chosen method and manner of consuming acidic drinks). The association between the presence of erosive lesions and the possible risk indicators was assessed by logistic regression analyses. Of all participants examined, 37% had ≥3 surfaces with dental erosions and were considered to be affected individuals. In the present study, multivariate logistic analyses revealed a significant association between the dental erosive wear and high consumption of sour sweets and sports drinks. The tooth-brushing frequency was not significantly associated with dental erosive wear. Additionally, to the best of our knowledge, the results are the first to indicate a dose-response relationship between the daily consumption of acidic drinks and dental erosive wear.

Objectives: To compare the wear and opposing enamel wear of adjusted (A); adjusted and polished (AP); and adjusted and glazed (AG) zirconia and lithium disilicate., Methods: Specimens (n=8) were prepared of lithium disilicate (A, AP, and AG), zirconia (A, AP, and AG), veneering porcelain, and enamel (control). Surface roughness was measured for each ceramic. In vitro wear was conducted in the UAB-chewing simulator (10 N vertical load/2mm slide/20 cycles/min) with lubricant (33% glycerin) for 400,000 cycles. Isolated cusps of extracted molars were used as antagonists. Scans of the cusps and ceramics were taken at baseline and 400,000 cycles with a non-contact profilometer and super-imposed to determine wear. Data were analyzed with ANOVA and Tukey-Kramer post hoc tests (alpha=0.05)., Results: A and AP zirconia showed no detectable signs of wear, and the veneering porcelain demonstrated the most wear. All other ceramics showed significantly less volumetric loss than the veneering porcelain, comparable to enamel-enamel wear. Veneering porcelain produced the most opposing enamel wear (2.15 ± 0.58 mm(3)). AP lithium disilicate and zirconia showed the least amount of enamel wear (0.36 ± 0.09 mm(3) and 0.33 ± 0.11 mm(3) respectively). AG lithium disilicate had statistically similar enamel wear as AP lithium disilicate, but A lithium disilicate had more enamel wear. A and AG zirconia had more enamel wear than AP zirconia. No statistically significant difference was seen between the enamel-enamel group and any other group except the veneering porcelain., Conclusions: Zirconia has less wear than lithium disilicate. Wear of enamel opposing adjusted lithium disilicate and zirconia decreased following polishing., Clinical Significance: Zirconia experiences less and lithium disilicate experiences equivalent occlusal wear as natural enamel. It is preferable to polish zirconia and lithium disilicate after adjustment to make them wear compatible with enamel. Veneering of zirconia and lithium disilicate should be avoided in areas of occlusal contact to prevent enamel wear., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Statement of Problem: The wear behavior of human enamel that opposes different prosthetic materials is still not clear., Purpose: The purpose of this in vitro study was to investigate and compare the friction and wear behavior of human tooth enamel that opposes 2 indirect restorative materials: lithium disilicate glass ceramic and Type III gold., Material and Methods: Friction-wear tests on human enamel (n=5) that opposes lithium disilicate glass ceramic (n=5) and Type III gold (n=5) were conducted in a ball-on-flat configuration with a reciprocating wear testing apparatus. The wear pairs were subjected to a normal load of 9.8 N, a reciprocating amplitude of approximately 200 μm, and a reciprocating frequency of approximately 1.6 Hz for up to 1100 cycles per test under distilled water lubrication. The frictional force of each cycle was recorded, and the corresponding friction coefficient for different wear pairs was calculated. After wear testing, the wear scars on the enamel specimens were examined under a scanning electron microscope., Results: Type III gold had a significantly lower steady-state friction coefficient (P=.009) and caused less wear damage on enamel than lithium disilicate glass ceramic. Enamel that opposed lithium disilicate glass ceramic exhibited cracks, plow furrows, and surface loss, which indicated abrasive wear as the prominent wear mechanism. In comparison, the enamel wear scar that opposed Type III gold had small patches of gold smear adhered to the surface, which indicated a predominantly adhesive wear mechanism., Conclusions: A lower friction coefficient and better wear resistance were observed when human enamel was opposed by Type III gold than by lithium disilicate glass ceramic in vitro., (Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Purpose: The aim of this systematic review was to assess enamel wear on teeth opposing zirconia restorations and to evaluate factors related to the wear of natural teeth opposing zirconia restorations., Materials and Methods: Five electronic databases were searched through May 2013 without limitations. The terms "antagonist*," "enamel," "wear," and "zirconi*" were used. Titles and abstracts were initially screened, and those that fulfilled the inclusion criteria were selected for a full-text assessment. Studies that evaluated only the material wear were not included., Results: The database search strategy retrieved 142 potentially eligible studies. After the duplicate studies were removed, 62 studies were obtained. Titles and abstracts that fulfilled the inclusion criteria were selected for a full-text assessment (25). Seven laboratory studies met the inclusion criteria. In addition, reference lists from the finally selected studies were also screened., Conclusions: There was a large variation in relation to wear test method quantification, applied force, lateral movement, number and frequency of cycles, number of specimens, and enamel specimen preparation. In all studies, enamel wear rates were lower against polished zirconia. Differences in the test methods did not allow for comparisons of wear rates among the studies., Clinical Significance: Polishing the surface is recommended for a full-contour zirconia restoration because polished zirconia presents favorable wear behavior opposing natural teeth., (© 2014 by the American College of Prosthodontists.)

Ring-tailed lemurs (Lemur catta) at the Bezà Mahafaly Special Reserve (BMSR), Madagascar display a high frequency of individuals with notable and sometimes extreme tooth wear. Adult lemurs display a range of tooth wear even among individuals of the same age, but we do not know at what age this variation first appears. This study's goal was to determine whether wear variation occurs in younger wild lemurs. Based on the decade-long study of ring-tailed lemur feeding and dental ecology at BMSR, we hypothesized that younger, natal lemurs (under 5 years of age), would display variation in their degree of tooth wear that would correspond to microhabitat differences, given differences in food availability in different troops' home ranges. We also hypothesized that wear would differ between sexes at this young age, given differences in feeding between males and females in this population. Hypotheses were tested using dental topographic analyses using dental impressions collected from known-aged lemurs across 10 years at BMSR. Results illustrate significant differences in wear-related tooth topography (i.e., relief and slope, presented here as "occlusal lift") for microhabitat, sex and troop affiliation among lemurs under 5 years of age in this population. Although, all lemurs in this population consume mechanically challenging tamarind fruit, those in more disturbed habitats eat additional introduced foods, some of which are also mechanically challenging. Thus, dietary variation is the likely cause of variation in tooth wear. The wear variation we show at a young age suggests caution when assigning age based on tooth wear in living and fossil primates. These wear-related tooth shape changes early in life, which reflects sex, habitat variation and levels of anthropogenic disturbance, may potentially impact reproductive fitness later in life., (© 2014 Wiley Periodicals, Inc.)

Statement of Problem: Zirconia complete-coverage crowns are being widely used as restorations because of their improved esthetic characteristics. Data about the enamel wear potential of this ceramic after chair side adjustments are sparse., Purpose: The purpose of this study was to investigate the 3-body wear of enamel opposing 3 types of ceramic (dense sintered yttrium-stabilized zirconia; Crystal Zirconia; DLMS) (Z), a lithium disilicate (IPS e-max CAD; Ivoclar Vivadent) (E), and a conventional low-fusing feldspathic porcelain (VitaVMK-Master; Vita Zahnfabrik) (P), treated to impart a rough, smooth, or glazed surface., Material and Methods: Twenty-four specimens of each of the zirconia and the lithium disilicate ceramic were sectioned from computer-aided design and computer-aided manufacturing blocks into rectangular plates (15×12×2 mm). Twenty-four specimens of the feldspathic porcelain were formed into disks (12 mm diameter) from powders compressed in a silicone mold. All specimens (n=72) were prepared according to the manufacturers' recommendations. Specimens of each ceramic group were placed into 1 of 3 groups: group R, rough surface finish; group S, smooth surface finish; and group G, glazed surface finish. A total of 9 groups with 8 specimens each were placed in a 3-body wear simulator, with standardized enamel specimens (n=72) acting as the substrate. The wear of the enamel specimens was evaluated after 50,000 cycles. The data were analyzed with 2-way ANOVA and the Tukey HSD multiple comparison test (α=.05)., Results: The data showed that the smooth zirconia group (ZS) was associated with the least amount of enamel wear (1.26 ±0.55 mm(2)). The most antagonistic enamel wear was associated with the glazed groups ZG (5.58 ±0.66 mm(2)), EG (3.29 ±1.29 mm(2)), and PG (4.2 ±1.27 mm(2))., Conclusions: The degree of enamel wear associated with monolithic zirconia was similar to conventional feldspathic porcelain. Smoothly polished ceramic surfaces resulted in less wear of antagonistic enamel than glazing., (Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Demand is increasing for ceramic and composite resin posterior restorations. However, ceramics are recognized for their high abrasiveness to opposing dental structure., Purpose: The purpose of this study was to investigate the wear of enamel as opposed to dental ceramics and composite resin., Material and Methods: Twenty-four test specimens (antagonists), 6 each of monolithic zirconia, glass ceramic, composite resin, and enamel, were prepared into cylindrical rods. Enamel specimens were prepared from 24 extracted human permanent molar teeth. Enamel specimens were abraded against each type of antagonist with a pin-on-disk wear tester under a constant load of 25 N at 20 rpm for 4800 cycles. The maximum depth of wear (Dmax), mean depth of wear (Da), and mean surface roughness (Ra) of the enamel specimens were measured with a profilometer. All data were statistically analyzed by 1-way ANOVA, followed by the Tukey test (α=.05). A paired t test was used to compare the Ra of enamel at baseline and after testing. The wear of both the enamel and antagonists was evaluated qualitatively with scanning electron microscopic images., Results: No significant differences were found in enamel wear depth (Dmax, Da) between monolithic zirconia (2.17 ±0.80, 1.83 ±0.75 μm) and composite resin (1.70 ±0.92, 1.37 ±0.81 μm) or between glass ceramic (8.54 ±2.31, 7.32 ±2.06 μm) and enamel (10.72 ±6.31, 8.81 ±5.16 μm). Significant differences were found when the enamel wear depth caused by monolithic zirconia and composite resin was compared with that of glass ceramic and enamel (P<.001). The Ra of enamel specimens increased significantly after wear tests with monolithic zirconia, glass ceramic, and enamel (P<.05); however, no difference was found among these materials., Conclusions: Within the limitations of this in vitro study, monolithic zirconia and composite resin resulted in less wear depth to human enamel compared with glass ceramic and enamel. All test materials except composite resin similarly increased the enamel surface roughness after wear testing., (Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

A 48-year-old man presented with worn dentition due to daytime bruxism. His chief concern was compromised esthetics due to short teeth. The occlusal vertical dimension was increased by 2 to 3 mm in the premolar area, and a maxillary titanium overdenture with composite resin facings was fabricated to address his concern. The advantages of this treatment, as opposed to complete coverage restorations, include preservation of tooth structure, lower cost, and shorter treatment time. Four years after insertion, the titanium overdenture continues to function successfully and to address the patient's concerns., (Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Physiologic changes occur in dental occlusion throughout life, resulting from the interplay between functional demands and reciprocating adaptive responses. These changes have been reported in the anthropological literature and they reflect evolutionary changes in the human stomatognathic system during the Paleolithic, hunter-gatherer period. Specific occlusal changes occur in response to different environments, leading to extensive variation within and between extinct and extant human populations. For example, functional demands can cause occlusal and interproximal tooth wear, resulting in shortening of the dental arch, continual tooth eruption and changes in masticatory patterns. Since the advent of farming through to our current industrialized culture, functional demands on the human masticatory system, and its adaptive responses to these demands, have been reduced considerably. Indeed, it is only occasionally that functional demands are severe enough to lead to obvious pathology in the modern human dentition. In contrast to normal masticatory activity, 'modern-day conditions' such as dental caries, periodontal disease and erosion, can lead to significant changes in dental occlusion that are pathological and need to be treated. The masticatory system is a dynamic, functional unit that displays considerable change over a lifetime. In this concept paper, it is proposed that modern human populations living in industrialized environments display dental occlusions that can be considered to be 'neotenous'; that is, our dentitions tend to reflect an unworn stage of our ancestors that was only seen in infants, juveniles and young adults. Clinicians can draw on both phylogenetic and ontogenetic perspectives of 'functional dental occlusion' to differentiate continual physiological changes occurring over time that require ongoing review, from pathological responses that require intervention., (© 2014 Australian Dental Association.)

Tooth surface loss can present in a variety of ways, some of which can appear rather strange on first examination. This case report demonstrates an unusual presentation of tooth surface loss (TSL) and its subsequent treatment. This loss of hard dental tissue appeared to be affecting the whole of the patient's remaining dentition, both lingually and buccally. Detailed questioning revealed the origins of this problem which turned out to be due to excessive use of an intra-oral Miswak chewing stick. Cinical Relevance: This article will enable clinicians to understand the importance of specific, targeted history-taking, involving a rare case of tooth surface loss as well as the use of minimally destructive restoration composites and a fibre-reinforced composite bridge.

Aging of dental zirconia roughens its surface through low temperature degradation. We hypothesized that age-related roughening of zirconia crowns may cause detrimental wear to the enamel of an opposing tooth. To test our hypothesis, we subjected artificially aged zirconia and reference specimens to simulated mastication in a wear device and measured the wear of an opposing enamel cusp. Additionally, the roughness of the pretest surfaces was measured. The zirconia specimens, artificially aged by autoclave, showed no significant increase in roughness compared to the nonaged specimens. Furthermore, no significant difference in material or opposing enamel wear between the aged and nonaged zirconia was seen. All zirconia specimens showed less material and opposing enamel wear than the enamel to enamel control or veneering porcelain specimens. Scanning electron micrographs showed relatively smooth surfaces of aged and nonaged zirconia following wear testing. The micrographs of the veneering ceramic showed sharp fractured edges and fragments of wear debris. Zirconia may be considered a wear-friendly material for restorations opposing enamel, even after simulated aging.

Unlabelled: The study evaluated if men and women with severe tooth wear were at increased risk of general bone loss. Enamel biopsies obtained from 50 subjects aged 47.5 ± 5 years showed decreased copper content, which was associated with reduced spine bone mineral density, suggesting deficits of this trace element contributing to bone demineralization, enamel attrition, and deteriorated quality of mineralized tissues., Introduction: The objective of this cross-sectional study was to assess associations between enamel trace minerals and bone mineral density (BMD) in severe tooth wear. We hypothesized that similar factors contributed to both the excessive abrasion of dental enamel and reduced BMD in subjects with tooth wear., Methods: Fifty patients aged 47.5 ± 5 years with severe tooth wear and 20 age-, sex-, and body mass index (BMI)-matched healthy volunteers with normal dental status were studied regarding dietary intakes of trace elements, serum and salivary copper (Cu), zinc (Zn), and calcium (Ca) concentrations, and serum PTH, osteocalcin, and hydroxyvitamin D levels. Tooth wear was determined using clinical examination based on standard protocol according to Smith and Knight. In all subjects, acid biopsies of the maxillary central incisors were carried out to assess mineral composition of the enamel. Atomic absorption spectroscopy with an air/acetylene flame was used to measure Ca and Zn, and graphite furnace atomic absorption spectroscopy was used to analyze Cu content. BMD was examined using dual energy X-ray absorptiometry., Results: Tooth wear patients had reduced lumbar spine, but not femoral, BMD relative to controls (p < 0.001). No differences were found in enamel Ca concentration and Zn content was slightly higher in tooth wear patients than in controls whereas Cu content was significantly decreased in the patients: 19.59 ± 16.4 vs 36.86 ± 26.1 μg/l (p = 0.01) despite similar levels of Cu in serum and saliva. The differences were independent of serum 25-OH-D, osteocalcin concentrations or PTH either., Conclusion: Severe tooth wear is associated with reduced spinal BMD. Enamel in adult individuals with severe tooth wear is low in copper content. Therefore, further work is needed to determine whether copper plays a role in bone pathophysiology in these patients.

Although toothbrushing is considered a prerequisite for maintaining good oral health, it also has the potential to have an impact on tooth wear, particularly with regard to dental erosion. Experimental studies have demonstrated that tooth abrasion can be influenced by a number of factors, including not only the physical properties of the toothpaste and toothbrush used but also patient-related factors such as toothbrushing frequency and force of brushing. While abrasion resulting from routine oral hygiene can be considered as physiological wear over time, intensive brushing might further harm eroded surfaces by removing the demineralised enamel surface layer. The effects of brushing on eroded dentine are not fully elucidated, particular under in vivo conditions. However, there are indications that brushing after an acid impact causes less additional hard tissue loss in dentine than in enamel. Toothbrushing frequency and force as well as toothbrush hardness were shown to act as co-factors in the multifactorial aetiology of non-cervical carious lesions. In vitro studies showed that toothbrushing abrasion is primarily related to the abrasivity of the toothpaste, while the toothbrush acts as a carrier, only modifying the effects of the toothpaste. The benefits of normal oral hygiene procedure exceed possible side effects by far, but excessive toothbrushing - especially of eroded teeth - might cause some harmful effects., (© 2014 S. Karger AG, Basel.)

The objective of this systematic review was to assess tooth wear against ceramic crowns in posterior region in vitro and in vivo. An electronic PubMed search was conducted to identify studies on tooth wear against ceramic crowns in posterior region. The selected studies were analyzed in regard to type of crowns, natural antagonist, measuring protocol and outcome. From a yield of 1 000 titles, 43 articles were selected for full-text analysis; finally, no in vitro and only five in vivo studies met the inclusion criteria. As there is heterogeneity in design, used measuring method, ceramics and analysis-form, a meta-analysis was not possible. Results of these studies are very controversial which makes a scientifically valid comparison impossible. This review indicated that some all-ceramic crowns are as wear friendly as metal-ceramic crowns. Up to now, it has been impossible to associate tooth wear with any specific causal agent. The role of ceramic surface treatment that might be responsible for the changing in rate of tooth wear seems undetermined as yet through clinical trials. The literature reveals that studies on this topic are subject to a substantial amount of bias. Therefore, additional clinical studies, properly designed to diminish bias, are warranted.

Chronic exposure to Industrial Noise (IN), rich in Low Frequency Noise (LFN), causes systemic fibrotic transformation and sustained stress. Dental wear, significantly increased with exposure to LFN, affects the teeth particularly through the circumpulpar dentin. Our goal is to understand the consequences of IN exposure on the circumpulpar dentin of Wistar rats. 10 Wistar rats were exposed to IN for 4 months, according to an occupationally simulated time schedule and 10 animals were used as age-matched controls. The first and the second upper and lower molars of each animal were processed for observation by Field Emission Scanning Electron Microscopy (FESEM) and Energy Dispersive Spectroscopy (EDS) analysis was performed. In exposed animals FESEM showed a 2.0 to 6.0 μm-dense mineral band between dentin and the pulp with no regular continuity with the tubules. This structure had a few tubules where the odontoblasts processes could be observed embedded within the band and collagen fibers were trapped inside. EDS analysis revealed that it was hydroxyapatite similar to dentin, with a higher carbon content. FESEM results show that the band may be tertiary reparative dentin formed by odontoblast-like cells, but the increased amount of carbon (EDS) could mean that it is sclerotic dentin. IN should be acknowledge as a strong stimulus, able to cause an injury to odontoblasts and to the formation of reparative tertiary dentin, in a process that may accelerate the aging of the teeth, either by direct impact of acoustic pressure pulsations or by increased stress and dental wear.

Purpose: The amounts of calcium (Ca), magnesium (Mg), zinc (Zn), and copper (Cu) in enamel may be crucial for maintaining its integrity and to attenuate potential environmental effects on teeth. The aim of this study was to examine whether the mineral composition of enamel could influence tooth wear., Materials and Methods: A total of 50 patients with severe tooth wear were compared with 20 healthy volunteers. Tooth wear was assessed using clinical examination according to the protocol of Smith and Knight. Subsequently, the maxillary central incisors of each subject were subjected to acid biopsies to assess the mineral composition in the enamel. Atomic absorption spectroscopy with an air/acetylene flame was used to analyze for Ca, Zn, and Mg. Graphite furnace atomic absorption spectroscopy was used to analyze for Cu., Results: The concentrations of Ca and Mg in tooth enamel were comparable in the study and control groups. Zn enamel content was higher in patients with tooth wear, and Cu enamel content was lower in these patients compared with the control group., Conclusion: The differing Zn and Cu contents in tooth enamel might offer a reason for excessive tooth wear in these patients. However, the results require further, more detailed study.

Problem: Although there is a high prevalence of noncarious cervical lesions (NCCLs), the etiology of these lesions remains contentious., Purpose: To evaluate the combined effects of cyclic fatigue stress and biocorrosion activity on NCCLs., Materials and Methods: Extracted premolar teeth were allocated into four groups (N = 10). Two groups were cyclically fatigue loaded (100 N; 72 cycles per minute; 9,200 cycles) and placed in either hydrochloric acid gel (pH = 0.1) or orange juice (pH = 4). The other two groups were stored in identical chemical solutions without fatigue load. The buccal-lingual width of each tooth was measured before and after testing. The depth of biocorrosion, normalized by the percentage change in buccolingual width, normalized by time (hour) was calculated. The data were analyzed using a two-way analysis of variance and Tukey's HSD multiple comparison test (α = 0.05)., Results: Mean (SD) of the depth of biocorrosion values were as follows: teeth receiving fatigue loading with hydrochloric acid gel exposure (1.003%/hour [0.063]) revealed a significantly higher depth of biocorrosion than the fatigue-loaded group with orange juice exposure (0.511%/hour [0.281]) (p < 0.01). For the groups without fatigue loading, those with hydrochloric acid gel (0.022%/hour [0.006]) had a significantly higher depth of biocorrosion than the group with orange juice (0.009%/hour [0.004]) (p < 0.01). The cyclically fatigue-loaded teeth with hydrochloric acid gel had a significantly greater depth of biocorrosion than either group without fatigue loading (p < 0.001)., Conclusions: Cyclic fatigue stress-acidic biocorrosion had a significant effect on the depth of the NCCLs., Clinical Significance: In order to manage the destructive NCCLs lesions properly, it is essential to understand the etiology of these lesions. The present study indicated that the combined mechanisms of cyclic fatigue stress and biocorrosion could contribute to the formation of NCCLs., (© 2013 Wiley Periodicals, Inc.)

Developmental enamel defects, presenting as enamel hypoplasia or opacities are caused by damage or disruption to the developing enamel organ as a result of inherited and acquired systemic conditions. The high prevalence of these defects in the primary dentition demonstrates the vulnerability of the teeth to changes in the pre- and postnatal environment. The presence of enamel hypoplasia increases the risk of primary teeth to early childhood caries and tooth wear as the defective enamel is thinner, more plaque retentive and less resistant to dissolution in acid compared to normal enamel. The purpose of this paper was to critically review the aetiology and clinical complications of developmental enamel defects in the primary dentition and propose recommendations for the clinical management of affected teeth., (© 2013 Australian Dental Association.)

Background: Anecdotally, tooth wear is increasing, perhaps attributable to diet. The irreversible surface loss may result in sensitivity and loss of form and function. Little data exist on the prevalence of tooth wear in Australian children. This study investigated consumption of potentially erosive foods and drinks, examining the prevalence, distribution of tooth wear and associations in a sample of children., Methods: Parents of 350, 6-12-year-olds reported their child's oral hygiene, dietary intake, medical and dental histories; 154 children (subsample) were examined. Associations were studied with single and multivariable analyses., Results: Tooth wear was parentally reported for 17% (59 children of the study population) and observed in 66% (102 of the subsample), particularly affecting primary teeth. Significant risk factors for parentally reported tooth wear were: consuming 2-4 cups soft drink/day (OR = 9.52), citrus flavoured sweets/gums ≥1/day (5.10), citrus fruits 1-2/wk (4.28); tooth grinding (5.32); medical condition present (2.48); male gender (2.80). Drinking 2-4 cups fruit juice/day was a significant risk factor for both parentally reported (3.23) and observed tooth wear (3.97)., Conclusions: Tooth wear appeared under-reported as some parents were unaware their child's teeth were affected. Significant risk factors for tooth wear were identifiable from children's histories. Risk factors should be addressed early so that tooth wear in the primary dentition does not affect permanent teeth., (© 2013 Australian Dental Association.)

Much attention is being paid in the current literature to the necessity of raising awareness of the problem of tooth wear. The aim of this paper is to discuss advantages, disadvantages and modifications of currently used tooth wear indices with particular attention drawn to the advantages of their use both in everyday practice and epidemiological research, as well as an attempt to make the choice of a wear index easier and better adjusted for the needs of a single patient or a group of patients. The paper compares index assessment attempts available in the current literature in the context of validity of criteria choices and reliability results. The role of supporting methods is stressed as they facilitate both diagnosis and storing of data on tooth wear, as well as usefulness of indices which comprise therapeutic recommendations.

Over the last century, humans from industrialized societies have witnessed a radical increase in some dental diseases. A severe problem concerns the loss of dental materials (enamel and dentine) at the buccal cervical region of the tooth. This "modern-day" pathology, called non-carious cervical lesions (NCCLs), is ubiquitous and worldwide spread, but is very sporadic in modern humans from pre-industrialized societies. Scholars believe that several factors are involved, but the real dynamics behind this pathology are far from being understood. Here we use an engineering approach, finite element analysis (FEA), to suggest that the lack of dental wear, characteristic of industrialized societies, might be a major factor leading to NCCLs. Occlusal loads were applied to high resolution finite element models of lower second premolars (P2) to demonstrate that slightly worn P2s envisage high tensile stresses in the buccal cervical region, but when worn down artificially in the laboratory the pattern of stress distribution changes and the tensile stresses decrease, matching the results obtained in naturally worn P2s. In the modern industrialized world, individuals at advanced ages show very moderate dental wear when compared to past societies, and teeth are exposed to high tensile stresses at the buccal cervical region for decades longer. This is the most likely mechanism explaining enamel loss in the cervical region, and may favor the activity of other disruptive processes such as biocorrosion. Because of the lack of dental abrasion, our masticatory apparatus faces new challenges that can only be understood in an evolutionary perspective.

The theory of non-carious cervical lesions (NCCLs) suggests that tooth flexure arising from cyclic, eccentric occlusal forces causes their formation and progression in vulnerable cervical regions of teeth. The etiology is still controversial. Attrition, corrosion, abrasion and stress-corrosion might act alone or in combination to initiate and perpetuate lesions. This review of the literature provides the basis for the diagnosis that can be used in consideration of treatment options.

Objectives: This study aimed to systematically review the scientific evidence for the association between noncarious cervical lesions (NCCL) and occlusal risk factors (ORF) [occlusal interferences in excursive movements; occlusal force; premature contacts; type of guidance; skid of centric occlusion to maximum intercuspidation] in adults., Sources: Pubmed, Web of Science, Cochrane, Lilacs, Clinical Trials, National Research Register and National Institute for Health were searched., Study Selection: From 1082 potentially eligible studies, 106 were selected for full text analysis. Two independent reviewers (Kappa=0.8; p<0.001) selected the studies, abstracted information and assessed quality based on standardised scales. Six cross-sectional, two case-controls and one clinical trial were included. Several occlusal variables were analysed among the studies, but there was no standardisation of the units used in the analysis of occlusal factors. The majority of studies did not find significant associations between NCCL and ORF. Three studies found associations between NCCL and some variables (occlusal contact area, right canine guidance, premature contacts in centric relation and working side) (p<0.05). The methodological quality varied across studies, and there was high heterogeneity among them., Conclusion: Current scientific evidence does not support an association between ORF and NCCL. Further prospective studies with standardised methods are vital to strengthen the evidence., Clinical Significance: Understanding the risk factors for NCCL is important to control the causes and to help the dentist choose the best approach for the patient. The evidence does not support intervention to alter some occlusal factors for the prevention or control of the progression of NCCL., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Abrasivity potential of dentifrices is assessed mostly in vitro due to practical, scientific, and ethical reasons. The two most used evaluation methods are based on the measurement of radioactive dentin release or dentin surface profile changes, after simulation of toothbrushing with dentifrices. The radiotracer method known as radioactive or relative dentin abrasivity (RDA) was developed decades ago and is the most frequently used today (the 'gold standard' for many). The RDA is a reasonably robust method considered a useful tool for the determination of the relative abrasive level of dentifrices and abrasive powders. Studying the level of abrasivity of dentifrices under laboratory conditions is important to develop new formulations, to evaluate quality control of production, and to obtain a rough estimate of its potential clinical abrasivity. However, it is inappropriate to use RDA values alone to determine clinical safety when considering that dental wear is multifactorial and in vitro dentifrice abrasivity level is only one of the variables potentially affecting this outcome. It is important to remember that individuals present significant behavioral differences when brushing that could dramatically affect the potential of abrasion of a particular dentifrice. RDA values should be just one of the multiple variables being taken into consideration by professionals when providing recommendations to prevent dental wear., (Copyright © 2013 S. Karger AG, Basel.)

The Stephan Curve has played a dominant role in caries research over the past several decades. What is so remarkable about the Stephan Curve is the plethora of interactions it illustrates and yet acid production remains the dominant focus. Using sophisticated technology, it is possible to measure pH changes in plaque; however, these observations may carry a false sense of accuracy. Recent observations have shown that there may be multiple pH values within the plaque matrix, thus emphasizing the importance of the milieu within which acid is formed. Although acid production is indeed the immediate proximate cause of tooth dissolution, the influence of alkali production within plaque has received relative scant attention. Excessive reliance on Stephan Curve leads to describing foods as "safe" if they do not lower the pH below the so-called "critical pH" at which point it is postulated enamel dissolves. Acid production is just one of many biological processes that occur within plaque when exposed to sugar. Exploration of methods to enhance alkali production could produce rich research dividends.

Objectives: The aim of this study was to evaluate a possible relationship between preferred chewing side (PCS) and the anterior guidance angle., Subjects and Methods: Forty dental nurses and technicians, aged 24-46 years, were each given a piece of chewing gum, which they chewed for about 3 min. At 7 regular intervals (every 15 s), they were interrupted by the principal investigator (P.L.) in order to observe on which side of their mouths they had the bolus of chewing gum. Moulds of their jaws were made and the position of the maxillary arch relative to temporomandibular joints was recorded with a facebow and transferred to a semi-adjustable articulator. After mounting the stone casts of each subject, a measure of the anterior guidance angle was taken with an adjustable incisal table., Results: Of the 40 subjects, 14 (35%) presented a PCS. Among the 14 subjects who preferred a chewing side, there was a correlation between the PCS and a low angulation of teeth constituting the anterior guidance on that side, but this correlation was statistically nonsignificant., Conclusion: In this study, we found that unilateral chewing creates uneven wear on the anterior teeth and changed the anterior guidance angulation., (© 2013 S. Karger AG, Basel.)

Since the origin of tooth wear (attrition, abrasion and erosion) is multi-factorial, its diagnosis is complicated but vital. The so-called Tooth Wear Evaluation System, introduced earlier, makes a systematic diagnostic approach possible. The system consists of various modules, which can be used by the practitioner depending on the goal. Two new modules have been added to the Tooth Wear Evaluation System. The Therapy Start Module can be used to determine which one of the possible treatment modalities (counseling, monitoring, or restorative treatment) should be chosen. The Level of Difficulty Module gives the practitioner indications of the level of difficulty that may be encountered during a restorative treatment.

Purpose: This study examined the wear resistance of human enamel and feldspathic porcelain after simulated mastication against 3 zirconia ceramics, heat-pressed ceramic and conventional feldspathic porcelain., Materials and Methods: Human teeth and feldspathic porcelain cusp were tested against ceramic discs. 5 brands were tested - 3 monolithic zirconia, Prettau, Lava, and Rainbow, one lithium disilicate, IPS e.max Press, and one feldspathic porcelain, Vita-Omega 900. The surface was polished using a 600 grit and 1200 grit SiC paper. Each group was loaded for 300,000 cycles in a chewing simulator. The wear resistance was analyzed by measuring the volume of substance lost. The wear surfaces were observed by scanning electron microscopy to determine the wear characteristics., Results: Vita-Omega 900 led to the greatest amount of enamel wears followed by IPS e.max Press, Prettau, Lava and Rainbow. There was a significant difference between Vita-Omega 900 and IPS e.max Press (p<0.05). The wear values for human enamel were significantly greater than those for feldspathic porcelain, regardless of the surface roughness of the ceramic specimens (p<0.05)., Conclusion: The wear behaviour of human enamel and feldspathic porcelain varies according to the type of substrate materials. On the other hand, 3 zirconia ceramics caused less wear in the abrader than the conventional ceramic., Clinical Significance: Dental professionals should be aware of the wear effect of dental restorations on the opposing teeth or restorations. The amount of enamel wear was highest in feldspathic porcelains whereas zirconia ceramics caused less wear on the opposing teeth., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Objectives: Nanofilled composite resins are claimed to provide superior mechanical properties compared with microhybrid resins. Thus, the aim of this study was to compare nanofilled with microhybrid composite resins. The null hypothesis was that the size and the distribution of fillers do not influence the mechanical properties of surface roughness and wear after simulated toothbrushing test., Material and Methods: Ten rectangular specimens (15 mm x 5 mm x 4 mm) of Filtek Z250 (FZ2), Admira (A), TPH3 (T),Esthet-X (EX), estelite sigma (ES), concept advanced (C), Grandio (G) and Filtek Z350 (F) were prepared according to manufacturer's instructions. Half of each top surface was protected with nail polish as control surface (not brushed) while the other half was assessed with five random readings using a roughness tester (Ra). Following, the specimens were abraded by simulated toothbrushing with soft toothbrushes and slurry comprised of 2:1 water and dentifrice (w/w). 100,000 strokes were performed and the brushed surfaces were reanalyzed. Nail polish layers were removed from the specimens so that the roughness (Ra) and the wear could be assessed with three random readings (µm). Data were analyzed by ANOVA and Tukey's multiple-comparison test (α=0.05)., Results: Overall outcomes indicated that composite resins showed a significant increase in roughness after simulated toothbrushing, except for Grandio, which presented a smoother surface. Generally, wear of nanofilled resins was significantly lower compared with microhybrid resins., Conclusions: As restorative materials suffer alterations under mechanical challenges, such as toothbrushing, the use of nanofilled materials seem to be more resistant than microhybrid composite resins, being less prone to be rougher and worn.

This study was conducted to verify the results of a preceding retrospective pilot study by means of a prospective controlled investigation including a larger sample size. Therefore, the aim of this clinical investigation was to analyze the relationship between sleep bruxism and several functional and occlusal parameters. The null hypothesis of this study was that there would be no differences among sleep bruxism subjects and non-sleep bruxism controls regarding several functional and occlusal parameters. Fifty-eight sleep bruxism subjects and 31 controls participated in this study. The diagnosis sleep bruxism was based on clinical criteria of the American Academy of Sleep Medicine. Sixteen functional and occlusal parameters were recorded clinically or from dental study casts. Similar to the recently published retrospective pilot study, with a mean slide of 0.77 mm (s.d., 0.69 mm) in the sleep bruxism group and a mean slide of 0.4 mm (s.d., 0.57 mm) in the control group, the evaluation of the mean comparison between the two groups demonstrated a larger slide from centric occlusion to maximum intercuspation in sleep bruxism subjects (Mann-Whitney U-test; P=0.008). However, following Bonferroni adjustment, none of the 16 occlusal and functional variables differed significantly between the sleep bruxism subjects and the non-sleep bruxism controls. The present study shows that the occlusal and functional parameters evaluated do not differ between sleep bruxism subjects and non-sleep bruxism subjects. However, as the literature reveals a possible association between bruxism and certain subgroups of temporomandibular disorders, it appears advisable to incorporate the individual adaptive capacity of the stomatognathic system into future investigations.

Aim: To determine the prevalence of signs and symptoms in a group of tooth wear patients referred to a hospital-based consultant clinic., Method: The clinical records of 290 patients referred to the Liverpool University Dental Hospital for tooth wear were reviewed retrospectively. A systematic sampling technique was used to select every alternate patient held on the consultant database., Results: There were significantly more males than females in a ratio of 2.3:1. Significantly more males (56%) presented with severe tooth wear compared with females (31%) (p <0.001). Aesthetic concerns were the most prevalent presenting complaint (59%) and sensitivity was the second most common presenting complaint (40%). Functional problems and pain were less prevalent at 17% and 14% respectively. Subjects who had lost posterior support had more severe wear and more worn anterior teeth, which was statistically significant (p = 0.001). The proportion of subjects with undiagnosed apical pathology on worn teeth was 13%., Conclusions: Tooth wear predominated in males in this study. Patient dissatisfaction with appearance is the most common complaint and endodontic signs and symptoms are low in prevalence. Contrary to previous studies, lack of posterior support resulted in greater severity of wear, therefore restoring support is recommended.

Piercing is the practice of puncturing some parts of the body to apply ornamental objects. The presence of oral and perioral piercings are a risk factor for many acute and chronic complications, such as chipping of the dental enamel, periodontal lesions and infection. The aim of this study is to assess the prevalence of lip and tongue piercing complications in the dental and periodontal tissues in a sample of young adults. Twenty-five adult patients were examined (test group: 11 males and 14 females with an average age of 23.4+/-3.6 years) who had had a minimum of one labial or tongue piercing for at least 1 year and were compared with 25 subjects (control group: 11 males - 44 percent, and 14 females - 56 percent) without any lingual or labial piercing. A questionnaire was compiled for each patient and a clinical examination was performed. The following parameters were examined by the same operator: abnormal toothwear, tooth chipping or cracking, clinical attachment loss (CAL), probing pocket depth (PD) and gingival recession (GR, classified by using Miller s classification). The data were analyzed using X2 or Fisher s exact test for small numbers and non-parametric Mann-Whitney or Kruskal-Wallis tests to examine for differences in continuity; the level of significance was p less than 0.05. According to the results found in the present study the prevalence of abnormal tooth wear and tooth chipping was higher in the subjects with labial or lingual piercing. Moreover, patients with tongue or labial piercing exhibited a higher GR in comparison to control subjects without any oral piercing. No differences were observed between the two groups as regards CAL and PD. A significant association between the duration of piercing and dental defects was found in the group of patients with piercings with greater prevalence of tooth and periodontal defects in the group of 13 subjects who had had the piercings for a period less than or equal to 4 years.

Buccal-dental microwear depends on the abrasive content of chewed foodstuffs and can reveal long-term dietary trends in human populations. However, in vivo experimental analyses of buccal microwear formation processes are scarce. Here, we report the effects of an abrasive diet on microwear rates in two adult volunteers at intervals of 8 days over a period of 1 month and document long-term turnover over 5 consecutive years in the same subjects under an ad libitum Mediterranean diet. Buccal microwear was analyzed on mandibular first molars using high-resolution replicas and scanning electron microscopy. Microwear turnover was assessed by recording the scratches lost and gained at each time point. Our results indicate that scratch formation on enamel surfaces increased with a highly abrasive diet compared to both pre-test and post-test ad libitum dietary controls. In the long-term analysis, scratch turnover was higher than expected, but no significant long-term trends in microwear density or length were observed, because microwear formation was compensated by scratch disappearance. Our results confirm that buccal microwear patterns on mandibular molars show a dynamic formation process directly related to the chewing of abrasive particles along with ingested food. In addition, the observed long-term stability of buccal microwear patterns makes them a reliable indicator of overall dietary habits., (Copyright © 2012 Wiley Periodicals, Inc.)

Unlabelled: One of the most common dental problems in today's clinics is tooth wear, specifically when related to bruxism. In such cases, the esthetics of anterior teeth may be compromised when excessive wear to the incisal surfaces occurs. Anterior tooth wear resulting from parafunctional bruxism can be conservatively treated with the use of direct resin composite restorations. This restorative approach has the advantages of presenting good predictability, load resistance, acceptable longevity, preservation of healthy dental tissues, and lower cost when compared with indirect restorations. The use of resin composites to solve esthetic problems, however, requires skill and practice. Thus, the present article demonstrates a conservative approach for restoring the esthetics and function of worn anterior teeth with the aid of direct resin composite restorations and selective occlusal adjustment., Clinical Significance: A conservative approach to restore anterior teeth with excessive wear is possible with direct resin composites., (© 2011 Wiley Periodicals, Inc.)

Objectives: Test the hypotheses that there are equivalent wear rates for enamel-versus-enamel and ceramic-versus-enamel, analyzing the in vivo wear of crown ceramics, their natural enamel antagonists, and the corresponding two contralateral teeth; and, that bite force does not correlate with the wear., Methods: A controlled, clinical trial was conducted involving patients needing full coverage crowns opposing enamel antagonists. Bite forces were measured using a bilateral gnathodynamometer. Single-unit restorations of metal/ceramic (Argedent 62, Argen Corp/IPS d.SIGN veneer); or, core-ceramic/veneer from either, Empress2/Eris, or e.max Press core/e.max Ceram glaze (ceramics: Ivoclar Vivadent, USA) were randomly assigned, fabricated and cemented. Impressions were made of the ceramic crowns, as well as each maxillary and mandibular quadrant at one week (baseline) and one, two and three years. Resulting models were scanned (3D laser scanner). Maximum wear was calculated by superimposing baseline with annual images., Results: There were a total of thirty-six crowns required for thirty-one patients. Each restoration had three associated enamel teeth: crown, (1) antagonist, (2) contralateral and (3) contralateral-antagonist. SAS PROC MIXED (α=0.05) indicated no statistical significance for mean maximum wear among crown ceramics, enamel antagonists and contralaterals. However, enamel wear was statistically significant in relation to intraoral location (p=0.04) and among years (p<0.02). Analyzed alone, the enamel contralateral-antagonist exhibited significantly greater wear (p<0.001). Considering all wear sites, there was no correlation with bite force (p=0.15)., Significance: The ceramics and their antagonists exhibited in vivo wear rates within the range of normal enamel. Future studies should examine the wear implications of the contralateral-antagonist enamel., (Copyright © 2012 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.)

Non-carious cervical lesions (NCCLs) are a group of lesions that affect the cervical area of the teeth. Different aetiological factors have been reported, among them tooth brushing force, erosive agents and occlusal forces. The aim of this study was to ascertain, by means of a systematic review, the association between NCCLs and occlusion. A search was performed in the MEDLINE database, retrieving a total of 286 articles. After title and abstract screening, the clinical investigations were read in full to select those that evaluated the occlusal aspects of NCCL aetiology. This systematic review describes the results of three prospective and 25 cross-sectional studies. As there is an extreme heterogeneity in design, diagnostic criteria, forms of analysis and associated factors, a meta-analysis was not possible. The wide variety of classification and diagnostic criteria reflects a high range of reported prevalence. An extensive heterogeneity of independent variables was noted, even in occlusal analysis, which helps to mask any conclusion about the role of occlusion in NCCL aetiology. The literature reveals that studies on this topic are subject to a substantial amount of bias, such as evaluation (use of non-blinded examiners) and confounding bias (no control of others aetiological factors). Up to now, it has been impossible to associate NCCLs with any specific causal agent, and the role of occlusion in the pathogenesis of non-carious cervical lesions seems as yet undetermined. Therefore, additional studies, properly designed to diminish bias, are warranted., (© 2012 Blackwell Publishing Ltd.)

Background: Prader-Willi syndrome (PWS) is a rare complex multsystemic genetic disorder characterized by severe neonatal hypotonia, endocrine disturbances, hyperphagia and obesity, mild mental retardation, learning disabilities, facial dysmorphology and oral abnormalities. The purpose of the present study was to explore the prevalence of tooth wear and possible risk factors in individuals with Prader-Willi syndrome., Methods: Forty-nine individuals (6-40 years) with PWS and an age- and sex-matched control group were included. Tooth wear was evaluated from dental casts and intraoral photographs and rated by four examiners using the Visual Erosion Dental Examination (VEDE) scoring system and the individual tooth wear index IA. In accordance with the VEDE scoring system, tooth wear was also evaluated clinically. Whole saliva was collected., Results: Mean VEDE score was 1.70 ± 1.44 in the PWS group and 0.46 ± 0.36 in the control group (p < 0.001). Median IA was 7.50 (2.60-30.70) in the PWS group and 2.60 (0.90-4.70) among controls (p < 0.001). In the PWS group tooth wear correlated significantly with age (VEDE; r = 0.79, p < 0.001, IA; r = 0.82, p < 0.001) and saliva secretion (VEDE; r = 0.46, p = 0.001, IA; r = 0.43, p = 0.002). Tooth grinding was also associated with tooth wear in the PWS group, as indicated by the mean VEDE 2.67 ± 1.62 in grinders and 1.14 ± 0.97 in non-grinders (p = 0.001) and median IA values 25.70 (5.48-68.55) in grinders and 5.70 (1.60-9.10) in non-grinders (p = 0.003). Multivariate linear regression analysis was performed with tooth wear as the dependent variable and PWS (yes/no), age, tooth grinding and saliva secretion as independent variables. PWS (yes/no), age and tooth grinding retained a significant association with tooth wear, VEDE (p < 0.001) and log IA (p < 0.001). The only factor significantly associated with tooth wear in the control group was age., Conclusions: Our study provides evidence that tooth wear, in terms of both erosion and attrition, is a severe problem in Prader-Willi syndrome. There is therefore considerable need for prosthodontic rehabilitation in young adults with PWS.