Severe Tooth Wear Research Articles

Digital Approach Provides Predictability in Increasing the VDO in Erosive Wear: Clinical Technique and 9-Year Follow-Up.

This clinical case describes a digital workflow using face scans and CAD/CAM technology for a full-mouth rehabilitation with increased vertical dimension of occlusion (VDO) with adhesive lithium disilicate restorations after 9 years. A healthy, 46-year-old man displaying severe tooth wear, underwent an extensive full-mouth rehabilitation involving an increase of the VDO through laminate veneers and adhesive partial coverage lithium disilicate restorations. Anatomical landmarks of the face and reference planes were captured using a digital face scanning system. The anatomical position of the maxilla was registered with a transfer device. Digital data sets of the intraoral situation combined with a facial scan enabled precise virtual planning, guiding minimally invasive preparations. Long-term provisional restorations, milled from high-performance polycarbonate, were used to test the novel VDO before the final lithium disilicate restorations were fabricated. This approach provided a time- and cost-efficient treatment solution. No failures were observed at the 9-year follow-up. Utilizing face scans and design software enable a virtual visualization and comprehensive quality control for patients with dental wear, resulting in significant time savings and increased predictability for the dental technician, dentist and patient. The described digital workflow optimizes the planning and implementation of a comprehensive adhesive full-arch rehabilitation with an increase of the VDO. The clinical long-term follow up result of CAD/CAM assisted minimally invasive lithium disilicate restorations after 9 years demonstrates to clinicians a reliable treatment concept for patients with dental wear.

Dental Caries and Erosive Tooth Wear Among 12-Year-Old Hong Kong Children

ObjectiveThis study is to investigate the dental caries, erosive tooth wear status, and oral health-related habits of 12-year-old Hong Kong children. MethodsThis cross-sectional survey recruited 12-year-old children using clustered random sampling from three main districts. The trained examiner examined the children's caries status using the criteria recommended by the World Health Organization and recorded their caries experience using the decayed, missing, and filled tooth (DMFT) index. The children's tooth wear status was determined using the Basic Erosive Wear Examination (BEWE) index. Their oral hygiene practice was collected using a self-administered questionnaire. ResultsWe recruited 445 children and 396 children participated (response rate: 89%). Their mean DMFT was 0.29 ± 0.73. Seventy children (18%, 70/396) had caries experience (DMFT > 0) and they had 116 teeth suffered from caries. Among these 116 carious teeth, 75 teeth (65%, 75/116) were filled (FT), one tooth (1%, 1/116) was extracted (MT), and 40 teeth (34%, 40/116) were carious (DT). Five children had more than one decayed tooth (DT > 1), and one child had the highest number of decayed teeth (DT) at 4. BEWE results showed 284 (72%, 284/396) children had no erosive tooth wear (BEWE = 0). No child had severe erosive tooth wear (BEWE = 3). However, children consuming lemon tea or lemonade and vitamin C drinks 3 times a week or more showed significantly higher BEWE scores. Additionally, 380 (96%, 380/396) children brushed their teeth daily and 116 children (29%, 116/396) flossed their teeth. ConclusionMost 12-year-old Hong Kong children had neither caries experience nor tooth wear, and their oral health-related habits were satisfactory. SignificanceThis study updated the caries status of the permanent dentition of 12-year-old Hong Kong children. The information offers updated oral health data for the local, regional, and global authorities for planning effective public health programmes to improve the oral health of children.

Prospective case series study on the survival rates of occlusal polymethyl methacrylate veneers as a semipermanent therapy in patients with severe pathologic tooth wear.

To evaluate the survival rate of minimally invasive semipermanent occlusal polymethyl methacrylate (PMMA) onlays/veneers in previous temporomandibular disorder (TMD) patients with severe tooth wear and with a loss of vertical dimension after up to 7 years. This case series was designed as a follow-up evaluation with consecutive patient recruitment. All patients bearing the indication for this kind of rehabilitation were treated by the same clinician using the same adhesive methodology. The study included 22 patients (3 men/19 women), with a mean ± SD age of 50.7 ± 11.6 years. Controls followed within the first 4 weeks (and subsequently as required). Failure criteria included damage by fracture, chipping, and retention loss. Survival rates were determined based on the Kaplan-Meier analysis. 328 semipermanent occlusal/incisal veneers were included (142 maxillary/186 mandibular teeth). Almost 80% of the restorations were in place and in function when starting the follow-up treatment after 180 days; failures predominantly occurred within the first 3 to 6 months but proved reparable. Depending on the patients' priorities, scheduled replacements followed successively, and more than 65% did not show repair or any renewal needs for more than 360 days. Within the limitations of this study the survival rates of occlusal veneers made of PMMA were sufficiently high to allow for consecutive treatment of the respective teeth by means of permanent restorations while preserving the restored vertical dimension. In patients with severe tooth wear and a TMD history, semipermanent restorative therapy with occlusal PMMA onlays/veneers would seem a noteworthy option.

Automated monitoring of tooth wear progression using AI on intraoral scans

ObjectivesThis study aimed to develop and evaluate a fully automated method for visualizing and measuring tooth wear progression using pairs of intraoral scans (IOSs) in comparison with a manual protocol. MethodsEight patients with severe tooth wear progression were retrospectively included, with IOSs taken at baseline and 1-year, 3-year, and 5-year follow-ups. For alignment, the automated method segmented the arch into separate teeth in the IOSs. Tooth pair registration selected tooth surfaces that were likely unaffected by tooth wear and performed point set registration on the selected surfaces. Maximum tooth profile losses from baseline to each follow-up were determined based on signed distances using the manual 3D Wear Analysis (3DWA) protocol and the automated method. The automated method was evaluated against the 3DWA protocol by comparing tooth segmentations with the Dice-Sørensen coefficient (DSC) and intersection over union (IoU). The tooth profile loss measurements were compared with regression and Bland-Altman plots. Additionally, the relationship between the time interval and the measurement differences between the two methods was shown. ResultsThe automated method completed within two minutes. It was very effective for tooth instance segmentation (826 teeth, DSC = 0.947, IoU = 0.907), and a correlation of 0.932 was observed for agreement on tooth profile loss measurements (516 tooth pairs, mean difference = 0.021mm, 95% confidence interval = [-0.085, 0.138]). The variability in measurement differences increased for larger time intervals. ConclusionsThe proposed automated method for monitoring tooth wear progression was faster and not clinically significantly different in accuracy compared to a manual protocol for full-arch IOSs. Clinical significanceGeneral practitioners and patients can benefit from the visualization of tooth wear, allowing quantifiable and standardized decisions concerning therapy requirements of worn teeth. The proposed method for tooth wear monitoring decreased the time required to less than two minutes compared with the manual approach, which took at least two hours.

A digital workflow for full-mouth rehabilitation using CAD-CAM tooth reduction template.

A digital workflow is presented for multiple transfers of targeted jaw relation and restorative spaces from interim to definitive restorations in patients with severe tooth wear. Following analysis of the targeted restorative space, segmented arch stereolithographic templates were digitally created and fabricated for precise control of reduction depth. Then, the jaw relation was transferred from the initially determined stabilization splint to the temporary fixed restoration and definitive restoration by using a digital articulator. This digital approach yielded a stabilized jaw relationship and restorative spaces transferring effect throughout successive stages of occlusal reconstruction resulting in satisfactory prosthetic outcomes.

Treatment decisions of patients with Class II Division 2 malocclusion and severe tooth wear: a systematic review

BackgroundThe treatment strategy for patients with severe tooth wear associated with Class II Division 2 malocclusion remains a major challenge for dental practitioners.ObjectivesTo systematically review and summarize the literature on treatment strategies, restoration procedures and clinical outcomes for Class II Division 2 malocclusion patients with severe tooth wear.MethodsA literature review was conducted using Pubmed, Embase, the Cochrane Library, and Web of Science to identify eligible articles. Publications until October 16th, 2023 were searched independently and cross-checked by two researchers.ResultsOf 1513 articles screened, 10 reports detailed treatment processes, including six males and four females aged 34–68 years old. Four articles recorded pre-treatment freeway space (FWS) values ranging from 5 to 9 mm. All ten cases had significant occlusal vertical dimension (OVD) loss and the increase in OVD after treatment ranged from 1 to 7 mm. Pre-prosthetic orthodontic treatment was performed in two cases, in one of which only the maxillary region was orthodontically treated. The most common restorations provided were full coverage restorations. In most cases, temporary restorations were applied before the permanent restorations for eight weeks to six months. Four different sequences of final restoration were proposed. Follow-up ranged from four months to six years and included seven patients, one of them showed symptoms of temporomandibular disorder (TMD).ConclusionsA multidisciplinary team (MDT) approach to treatment is recommended. Consideration of pre-prosthetic orthodontic treatment is essential. Commonly used cephalometric measurements for anterior teeth include the interincisal angle and collum angle. The increases in OVD ranging from 1 to 7 mm can be effectively accommodated. Temporary restorations are recommended to accommodate the OVD, and the transition periods of 8 weeks to 6 months help the patients adapted well. Four different sequences for final rehabilitation have demonstrated positive clinical outcomes. Full crown restorations have emerged as the preferred choice for the ultimate restoration of these patients.

The survival and clinical performance of anterior composite resin restorations and posterior indirect and cast restorations used to treat generalised tooth wear

Objective To evaluate the survival and clinical performance of restorative materials used in the rehabilitation of generalised severe tooth wear within a UK NHS postgraduate teaching hospital.Methods The clinical performance of 527 restorations on 20 patients with generalised severe tooth wear was reviewed after a mean period of five years. Anterior teeth were restored with direct composite resin and posterior teeth with indirect restorations. The study used the modified United States Public Health Service criteria for restoration assessment. Survival of the restorations was analysed using Kaplan-Meier survival curves, the log-rank test and the Cox proportional hazards regression analysis.Results The sample included 20 participants: 13 men and 7 women, with a median age of 51.8 years (range: 33-73 years). The median survival time for all restorations was 11.3 years when major failures were considered and 5.9 years for restorations when all types of failure were considered. A median survival time of 5.9 years for composite resin restorations and over seven years for cast restorations was found when considering all failures. Composite resin restorations commonly failed as a result of fracture, wear and marginal discolouration. Factors significantly influencing restoration survival were the material used, aetiology, incisal relationship and tooth location. The biological complications associated with this treatment regime were rare. Patient satisfaction remained generally high, with greatest dissatisfaction related to treatment time.Conclusions The use of anterior composite resin with posterior indirect restorations to treat generalised severe tooth wear is a viable treatment modality with very few major complications.

Resistance of CAD/CAM composite resin and ceramic occlusal veneers to fatigue and fracture in worn posterior teeth: A systematic review.

Severe tooth wear is related to substantial loss of tooth structure, with dentin exposure and significant loss (≥1/3) of the clinical crown. The objective of this systematic review was to summarize and analyze the scientific evidence regarding the mechanical performance of computer-aided design/computer-aided manufacturing (CAD/CAM) composite resin and CAD/CAM lithium disilicate ceramic occlusal veneers, in terms of fatigue and fracture resistance, on severely worn posterior teeth. Currently, occlusal veneers are an alternative for treating worn posterior teeth. Although scientific evidence demonstrates the good performance of lithium disilicate occlusal veneers, there are less brittle materials with a modulus of elasticity more similar to dentin than ceramics, such as resin CAD/CAM blocks. Therefore, it is important to identify which type of material is best for restoring teeth with occlusal wear defects and which material can provide better clinical performance. This review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A comprehensive search of the PubMed, Embase, Web of Science, Scopus, Cochrane, OpenGrey, Redalyc, DSpace, and Grey Literature Report databases was conducted and supplemented by a manual search, with no time or language limitations, until January 2022. We aimed to identify studies evaluating the fatigue and fracture resistance of CAD/CAM composite resin and ceramic occlusal veneers. The quality of the full-text articles was evaluated according to the modified Consolidated Standards of Reporting Trials (CONSORT) criteria for in vitro studies, and 400 articles were initially identified. After removing duplicates and applying the selection criteria, 6 studies were included in the review. The results demonstrated that the mechanical performance of CAD/CAM composite resin occlusal veneers is comparable to that of CAD/CAM lithium disilicate occlusal veneers in terms of fatigue and fracture resistance.

Intraoral wear of PICN CAD-CAM composite restorations used in severe tooth wear treatment: 5-year results of a prospective clinical study using 3D profilometry

ObjectivesTo evaluate, in a prospective clinical study over 5 years with ex vivo 3D profilometry analyses, the intraoral wear of Polymer-Infiltrated Ceramic Network (PICN) CAD-CAM composite restorations used in severe tooth wear treatment with the One-Step No-Prep technique. Methods192 PICN (Vita Enamic) restorations on molars and premolars were included in a prospective clinical study involving patients treated according to the One-step No-prep protocol (n = 7). All patients showed clinical signs of bruxism. Replicas of restorations on molars and premolars were realized at each evaluation time (baseline and then every year up to 5 years) and scanned to perform 3D profilometry. Baseline and recall scans were superimposed with Geomagic Control software. The mean material wear was calculated for the full occlusal area (FOA) and for the occlusal contact area (OCA), respectively. Clinical evaluation of restorations was performed at recall. ResultsAt 5 years, the estimated mean material wear for FOA was inferior to the accuracy threshold of the profilometry measurement chain. For OCA, the estimated mean wear of the material was – 27.97 µm. This material wear was shown to be significantly influenced by time (p < 0.0001) and patient (p = 0.026), while the type of tooth (molar or premolar) had no influence. At 5 years, the survival and the success rates of restorations were 99.48% and 90.62%, respectively. SignificanceThe PICN material exhibits a low wear process in the treatment of severe tooth wear despite the presence of clinical signs of bruxism, and it constitutes a suitable material for the One-step No-prep technique.

Dental and Implantoprosthetic Rehabilitation of the Vertical Dimension in an Elderly Patient with Severe Parafunction

Tooth wear can have several etiological factors. When they occur in combination, the clinical result can be quite devastating, with severe tooth destruction. The purpose of this article is to present the case of a elderly patient with severe tooth wear caused by parafunctional habits (bruxism), with a marked reduction in the vertical dimension of the lower third of the face. Dental and implantoprosthetic rehabilitation was carried out, restoring the vertical dimension.

A case of oral rehabilitation in a patient with severe tooth wear and occlusal plane collapse, utilizing maxillary fixed prosthesis and mandibular implant-assisted removable partial denture

A case of oral rehabilitation in a patient with severe tooth wear and occlusal plane collapse, utilizing maxillary fixed prosthesis and mandibular implant-assisted removable partial denture

Digital Full-mouth Rehabilitation for Complex Cases Involving Severe Deep Overbite and Worn Dentition: A Case Report

Introduction: The demand for aesthetic restorations in dentistry has led to full-mouth reconstructions or rehabilitations (FMRs) as a viable solution for treating patients with worn and altered teeth. This study presents a clinical case report of a middle-aged patient with severe tooth wear and deep overbite with digital workflows. Case Presentation: The case report highlighted the successful application of digital technology in the comprehensive rehabilitation of a patient with worn dentition, showcasing improved esthetics, function, and patient comfort. The case report demonstrated the potential benefits of this rapid approach in achieving successful outcomes. Digital CAD/CAM technology is a solution for optimizing the prosthetic workflow, achieving time and cost efficiency, and delivering high-quality dental restorations. Conclusion: Future primary studies with larger sample sizes and longer follow-ups can further validate the FMR digital approaches.

Advanced Dental Rehabilitation in Case of Severe Tooth Wear Caused by Gastroesophageal Reflux Disease and Bruxism During COVID-19 Pandemia: A Case Report

Stomatological manifestations of psychosomatic diseases can be associated, culminating in advanced oral alterations. These psychosomatic changes have also increased during the COVID-19 pandemic. In this perspective, parafunctional habits, such as bruxism and clenching, and gastro-oesophageal reflux disease can develop major dental destruction. Thus, various types of treatment are required in the rehabilitation of these patients. The purpose of this article is to present the case of a patient who developed severe tooth wear due to the association between gastro-oesophageal reflux disease and bruxism, during the COVID-19 pandemic. The patient was treated with a bite raising, direct composite restorations and removable prostheses.

Inter- and intra-variability in tooth wear progression at surface-, tooth- and patient-level over a period of three years: A cohort study: Inter- and intra-variation in tooth wear progression

ObjectiveTo explore the variability of tooth wear progression at the surface-, tooth- and patient-level over a period of three years three years using in vivo 3D-measurements of full dentitions amongst patients with moderate to severe tooth wear and without demand for restorative rehabilitation. MethodsFifty-five eligible patients with moderate to severe tooth wear had intra-oral scans taken using either the 3 M True Definition Intraoral Scanner or the 3 M Lava Chairside Oral Scanner. The maximum height loss (µm) per cusp/incisal/palatal surface at unrestored surfaces was measured using the 3D Wear Analysis (3DWA)-protocol with Geomagic Qualify, resulting in sixty-four measurements per dentition. Data was visualized using box plots. Correlation was calculated between tooth wear progression rates of different tooth types and surfaces. ResultsThirty patients with scans at intake and after three years were included (38 ± 8 years, 77% M, 23% F). Mean observation time was 3.1 ± 0.2 years. Surface measurements (N = 1,615) showed a high deviation and a high number of outliers at all surfaces, indicating large variability amongst the surfaces, tooth types and patients with tooth wear progression rates. Correlations between regions were very low: anterior-molar region -0.219, anterior-premolar region 0.116 and premolar-molar region 0.113. Correlations between the surfaces of molars were also low (between 0.190 and 0.565). ConclusionsIn a group of patients with moderate to severe tooth wear, large differences in wear progression were found within and amongst patients. Tooth wear progression is therefore highly individualized and can be very localized. Clinical significanceThis study confirms the necessity of individual management of patients with moderate to severe tooth wear. Effective monitoring of tooth wear is important when deciding the timing and need for restorative intervention. Clinical Trial Registration NumberNCT04790110

Total Rehabilitation Using Adhesive Dental Restorations in Patients with Severe Tooth Wear: A 5-Year Retrospective Case Series Study.

Currently, there is little clinical evidence to support the medium- and long-term survival and clinical performance of ultraconservative approaches using adhesive restorations in full-mouth restorations. The aim of this case series study was to evaluate the medium-term clinical performance of anterior and posterior adhesive restorations applied with direct and indirect techniques using resin composites and glass-ceramic-based materials. The inclusion criteria were an esthetic problem as the main reason for consultation and severe generalized wear of grade 2 to 4 according to the Tooth Wear Evaluation System (TWES 2.0). In addition, at each follow-up appointment, patients were required to submit a clinical-parameter-monitoring record according to the modified United States Public Health Service (USPHS) criteria. Eight patients with severe tooth wear were treated through full rehabilitation in a private dental clinic in Spain by a single operator (AFC). A total of 212 restorations were performed, which were distributed as follows: 66 occlusal veneers, 26 palatal veneers and 120 vestibular veneers. No signs of marginal microleakage or postoperative sensitivity were observed in any occlusal, vestibular and/or palatal restoration after the follow-up period. The estimated survival rate of the 212 restorations was 90.1% over 60 months of observation, with a survival time of 57.6 months. Only 21 restorations had complications, which were mostly resolved with a direct composite resin. The dichotomous variables of the restoration type (posterior veneer, anterior veneer) and the type of restored tooth (anterior, posterior) were the risk predictors with statistically significant influences (p < 0.005) on the survival of the restorations. According to the results of this study, there is a significantly higher risk of restorative complications in posterior teeth compared to anterior teeth. Also, it can be concluded that the indication of adhesive anterior and posterior restorations is justified in the total oral rehabilitation of patients with severe multifactorial tooth wear, as they are associated with a low risk of failure.

Perception of oral health related quality of life and orofacial aesthetics following restorative treatment of tooth wear: A five-year follow-up

ObjectivesNon-carious tooth wear often has a multifactorial etiology and may lead to functional or aesthetically related problems. The most common complaints associated with tooth wear are dissatisfaction with dental appearance and a negative impact on the experienced Oral Health Related Quality of Life (OHRQoL). The aim of this study was to investigate the change in OHRQoL and the perception of aesthetics, following restorative treatment of moderate to severe tooth wear patients, with a five-year follow-up. MethodsAn explorative study, based on prospective data, was performed. OHRQoL and the perception of aesthetics were measured with the OHIP-NL and OES-NL. These questionnaires were completed before treatment, one month after treatment, and at 1-, 3- and 5-years post-treatment. Treatment involved full mouth reconstruction with composite resin restorations. The data was analysed as repeated measures by using a linear mixed-effects model. ResultsOne hundred and twenty-three tooth wear patients that received restorative rehabilitation were included (97 males, 26 females, 37.5 ± 8.8 years-old). Data showed a statistically significant increase in both experienced OHRQoL and orofacial appearance after restorative treatment. The OHIP-scores remained stable over time, while the OES-scores slightly decreased during the years after treatment. Regarding the seven domains of the OHIP, the largest difference in OHIP-score was found in the domain of ‘Psychological Discomfort’. The mean overall OHIP-score was 1.8 at baseline and 1.3 at the 5-years recall. The mean OES score increased from 41.8 at baseline to 66.1 at the 5-years follow-up. ConclusionsTooth wear patients reported significant improvements in their OHRQoL and their perception of orofacial aesthetics after restorative treatment. This increase remained at least five years post-treatment. Clinical SignificanceThe clinical impact of restorative treatment for tooth wear patients is considerable. This paper emphasizes the need to include a discussion of the patient related outcome measures when planning care.

The association of severely worn dentition resulting from betel nut chewing with temporomandibular disorders: a cross-sectional study

BackgroundMost studies support parafunctions play an important role in temporomandibular disorders (TMD), whereas the association between tooth wear and TMD remains controversial. Betel nut chewing as a parafunction is popular in South and Southeast Asia. We therefore investigated the association of severely worn dentition resulting from betel nut chewing with TMD.MethodsA cross-sectional analysis of 408 control participants (male: 380, female: 28, 43.62 ± 9.54 years) and 408 participants with betel nut chewing related severely worn dentition (male: 380, female: 28, 43.73 ± 8.93 years) who received dental and TMD checkup according to Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) in Health Management Center, Xiangya Hospital was performed. Betel nut chewing related severely worn dentition meant all the natural teeth had moderate to severe tooth wear [Tooth Wear Index (TWI) ≥ 2)] including ≥ 2 severe wear teeth (TWI ≥ 3) due to betel nut chewing. Multivariable logistic regression analysis was used.ResultsAfter adjusting for age, gender, betel nut chewing related severely worn dentition, oral submucosal fibrosis, number of missing teeth, number of dental quadrants with missing teeth, visible third molar and orthodontic history, variables of age, gender and betel nut chewing related severely worn dentition were significant for overall TMD. Multivariable analysis showed betel nut chewing related severely worn dentition was significantly associated with intra-articular TMD [odds ratio and 95% confidence intervals: 1.689 (1.271–2.244), P = 0.001] in a betel nut chewing dose-dependent manner.ConclusionBetel nut chewing related severely worn dentition was associated with intra-articular TMD.

Oral Health of Sambaqui Groups in Saquarema, Brazil

This article presents differences and similarities in dietary practices of fisher-gatherer groups excavated from two sambaquis (shell-mound archaeological sites) in Saquarema, Rio de Janeiro state, Brazil. We analyzed the buccal apparatus of 35 individuals excavated from Sambaqui da Beirada, dated from 5437 to 3440 years cal BP, and Sambaqui do Moa, dated from 4770 to 3199 years cal BP. Our oral health analysis of 852 alveoli and 704 teeth assessed the frequency and degree of teeth wear and the prevalence and frequency of caries, linear enamel hypoplasia, calculus, periapical cavities, and antemortem teeth loss. We applied the chi-square test and Fisher exact test to test statistical significance. Severe tooth wear, the absence of caries, a high frequency and prevalence of dental calculus, and a low prevalence of linear enamel hypoplasia were found in both sites, although periapical cavities and antemortem teeth loss indexes varied greatly. Despite a superficial homogeneity, the results point to variation in the physiopathological processes that occurred at both sites, including differences related to age and sex. These oral health-related results, together with other archaeological data from both sambaquis, showcase the expected cultural differences stemming from dietary practices.

Wear behaviour of direct composite restorations in tooth wear patients: a 5-year clinical study

ObjectiveThis study aimed to investigate the wear behaviour of direct composite restorations after 5 years and associated patient factors. Methods38 patients (6 females, 32 males; 35.2 ± 7.6y) from the Radboud Tooth Wear Project with generalized moderate to severe tooth wear were treated with direct composite restorations on all teeth. Ethical approval was sought and granted before the study was undertaken. Intraoral 3D scans were recorded at 1 month (baseline) and 5 years (recall) after treatment. The amount of height loss was measured at six index teeth (first molars and upper central incisors). Patient factors (age, vertical dimension of occlusion increase, bite force, aetiology score, jaw position and bearing/ non-bearing cusps) were included in the analysis. Multilevel multiple regression with bootstrapping was used to analyse the influence of these factors on wear behaviour of restorations. Observer reliability was tested by paired t-tests and Band-Altman plots (p<0.05) ResultsAfter 5 years, the mean height loss was 0.23± 0.19 mm for incisors and 0.43± 0.24 mm for molars (p≤0.001). Patient factors did not show any significant influence on height loss of the composite restorations, while bearing cusps showed significant more wear compared to non-bearing cusps (p≤0.001). The observer reliability tests confirmed the repeatability (correlation of 0.809, DME 0.103). ConclusionsWear of composite restorations is a significant and relevant factor over time in patients treated with severe tooth wear. Within the limitations of this clinical study, patient factors were found not to have a significant effect on wear behaviour of direct composite restorations.

Measuring tooth wear with regular intra-oral 3D scanners: for still in the future, or is it already possible?

Quantitative tooth wear measurement is a method of increasing importance when measuring tooth wear progression. The Radboud university medical center has developed a protocol that measures height and volumetric differences on regular 3D-scans. Intra-oral scans were made on patients with tooth wear and superimposed. To assess reliability the precision , as well as intra- and inter-rater precision of the protocol was tested. T-tests were performed to determine the structural and random error. Our findings indicate that the method is precise enough to measure height differences in patients with severe tooth wear progression, or tooth wear with an interval longer than 1 year. The method is not precise enough to measure volumetric changes.