Tooth wear in aging people: an investigation of the prevalence and the influential factors of incisal/occlusal tooth wear in northwest China

Age estimation in Indian soldiers: Maxillary anterior tooth pulp/tooth volume ratio analysis with cone beam computed tomography

Background

The objective of this study was to investigate the utility of Cone Beam Computed Tomography (CBCT)-based pulp tooth volume- ratio of maxillary anterior teeth for accurate age estimation. The project aimed to utilize the HOROS software for image analysis and develop prediction models using regression analysis.

Methods

1800 male patients in the age group of 20 to 40 years were selected, and maxillary anterior teeth were picked. High-resolution CBCT scans were collected, and image analysis in terms of pulp volume (PV), tooth volume (TV), and pulp-volume-to-tooth-volume ratio (PV/TV) was calculated using HOROS software. Simple linear regression analysis was used to develop prediction models correlating the PV/TV with chronological age.

Results

PV/TV of all teeth ranged between 0.073 and 0.214. Pearson correlation coefficient was used to evaluate the correlation between the chronological age and the PV/TV. It shows a statistically significant (positive) but low correlation between age and PV/TV 13 and 22 (combined), respectively, and the highest Pearson correlation (0.849) for maxillary canine (13). This study presents four models for age estimation with maximum standard error ranging between 3.5 and 4.3 and an accuracy of 96%.

Conclusion

This study illustrates the effectiveness of CBCT-based PV/TV of maxillary anterior teeth for age assessment. Accurate prediction models were constructed by using regression analysis and the HOROS software. These findings enhance the study of forensic odontology and have potential applications in forensic investigations, archaeological research, and legal-age assessment. Further research is necessary to validate and refine the prediction models, expanding their applicability to larger and more diverse population samples.

Intraoral Scanning for Monitoring Dental Wear and Its Risk Factors: A Prospective Study

Dental wear arises from mechanical (attrition or abrasion) and chemical (erosion) factors. Despite its prevalence and clinical significance, accurately measuring and understanding its causes remain challenging in everyday practice. This one-year study with 39 participants involved comprehensive examinations and full-arch intraoral scans at the start and after 12 months. Volume loss exceeding 100 µ on each tooth's surfaces (buccal, lingual/palatine and incisal/occlusal) was measured by comparing three-dimensional scans from both time points. This study also assessed factors such as abrasion and erosion through clinical exams and questionnaires. There were no significant differences in dental wear in participants with sleep bruxism. However, noticeable wear occurred in the front teeth of those with waking bruxism and joint-related symptoms. Increased wear was associated with frequent consumption of acidic drinks, regular swimming, dry mouth, nocturnal drooling and heartburn, while no significant wear was found in patients with reflux. The used methodology proved effective in accurately assessing the progression of dental wear, which is important as many patients may initially be asymptomatic. The variability observed in dental wear patterns underscores the need to develop specific software applications that allow immediate and efficient comparison of wear areas based on extensive analysis of patient databases.

The Prevalence of Tooth Wear and Their Associated Etiologies Among Adult Subjects Visiting Umm Al-Qura University Dental Clinic in Makkah City, Saudi Arabia

In the past two decades, changing trends in socioeconomic status, dietary habits, and individual lifestyles of individuals have led to the emergence of tooth wear as an oral health problem. The present study aimed to investigate the prevalence and the associated etiologies of tooth wear in a convenience sample of adult patients visiting outpatient clinics of the Faculty of Dentistry at Umm Al-Qura University. This cross-sectional study was conducted on adult patients (18-40 years old) visiting outpatient clinics of the Faculty of Dentistry, Umm Al-Qura University. Two trained examiners visually assessed patients' tooth wear using Smith and Knight's Tooth Wear Index (TWI). Following the clinical examination, patients completed a self-administered questionnaire detailing risk factors such as the frequency of intake of acidic food and medicines, general health, chewing habits, dietary factors, and oral health-associated preventive behaviors. The resulting collected data were tabulated and statistically analyzed using Statistical Product and Service Solutions (SPSS, version 21; IBM SPSS Statistics for Windows, Armonk, NY). The total prevalence of tooth wear was 74%, and the recorded mean wear score (TWI) was 0.380 ± 0.386; anterior teeth exhibited greater wear than posterior teeth. Numerous associations were recorded between tooth wear and the tested variables in demographics, habits, diet, and medications, but most of them were not statistically significant. When toothbrushing habits were explored, the only factors to played a significant role in abrading the tooth structure were the type of brush bristles used (P-value = 0.026) and the frequency of brush renewal (P = 0.043). Patients who frequently ate citrus fruits and other acidic foods recorded high wear scores (0.509 ± 0.311 and 0.508 ± 0.402, respectively), although the difference was not statistically significant. When chewing occurred on both sides of the mouth, less tooth wear was recorded than if chewing was on the right or left side only (0.371 ± 0.260, 0.422 ± 0.273, and 0.520 ± 0.419, respectively). The study data support an association between tooth wear and patient occupation, use of hard-bristled and new toothbrushes, eating of citrus and other acidic food, and chewing on one side, as all of these factors increased the risk of tooth wear.

Long-term occlusal tooth wear at the onset of permanent dentition

OBJECTIVES

This study quantified the long-term occlusal wear in the natural posterior teeth and the associations per tooth type within the dentition.

METHODS

The sample included 70 orthodontically treated subjects (52 females and 18 males; median age, 14.3 years), followed for a 12.7-year period. They were consecutively selected with no tooth wear-related criteria. Post-treatment (T1) and follow-up dental casts (T2) were scanned and superimposed through three-dimensional methods. Occlusal wear volume of posterior teeth and tooth wear patterns were investigated through non-parametric statistics and analysis of covariance.

RESULTS

There were no significant differences between contralateral teeth. The average occlusal wear per posterior tooth was 2.3 mm3, with 65.2% of teeth showing values greater than 1 mm3. Males, mandibular teeth, and first molars exhibited slightly greater wear levels than females (median, 2.57 and 2.21 mm3, respectively; p = 0.005), maxillary teeth, and first or second premolars, respectively. In all first premolars and in the mandibular second premolars, the buccal cusps were primarily affected with no other distinct patterns. There were weak to moderate correlations between tooth types, apart from certain strong correlations detected in males.

CONCLUSIONS

Posterior tooth wear was highly prevalent after a 13-year period starting at the onset of permanent dentition. The detected patterns are in accordance with the concept of canine guidance occlusion that is transforming into group synergy through function.

CLINICAL RELEVANCE

The widespread tooth wear occurrence and the high intra- and inter-individual variability underline the need for individual patient monitoring to identify high-risk patients at early stages.

Sex determination and odontometric dimensions - A study of a North Indian population

Sex determination is an indispensable parameter in identifying unknown deceased individuals. It can narrow down the chances of possible matches by 50%, providing a crucial lead in personal identification. In cases of commingled, decomposed, fragmented, charred and unidentifiable corpses, the importance of dental morphometrics cannot be overlooked due to the resistance of teeth to post-mortem degradation. Addressing this quality of teeth, a descriptive cross-sectional study was conducted in a North Indian population to evaluate sexual variations in dental dimensions and to identify the most sexually dimorphic dental dimension. The study included 207 participants (114 females and 93 males) in the age group of 21 to 45 years. Dental casts were prepared after obtaining informed consent from the participants and ethical clearance from the institute's ethical committee. Six odontometric dimensions, namely incisor-incisor distance, inter canine distance, combined width of central incisors, inter-premolar distance, inter-molar distance, and dental arch height of each participant were recorded on the dental casts using standard procedures. Analysis of the data elucidated the existence of statistically significant sexual dimorphism in the dental dimensions of the participants. The results of the discriminant function analysis show a sex determination accuracy of 68.1%, with a cross-validation accuracy of 65.2%. The study found the incisor-incisor distance to be the most sexually dimorphic trait, making it the best predictor of sex in the present population. The results of the present study may be helpful in sex determination and personal identification from dental remains in medico-legal and disaster victim identification cases.

Risk factors of tooth wear in permanent dentition: A scoping review

BACKGROUND

Tooth wear (TW) prevalence is high and increasing and has important consequences on the patient's quality of life. Knowledge of risk factors is crucial to promote diagnosis, prevention strategies and timely interceptive treatment. Many studies have identified TW risk factors.

OBJECTIVE

This scoping review aims to map and describe suspected available factors associated with TW in permanent dentition based on quantitative measurement.

METHODS

The scoping review was conducted using the PRISMA extension of the Scoping Reviews checklist. The search was conducted in October 2022 from the Medline® (PubMed® interface) and Scopus® databases. Two independent reviewers selected and characterised the studies.

RESULTS

2702 articles were identified for assessment of titles and abstracts, and 273 articles were included in the review. The results show a need to standardise TW measurement indices and the study design. The included studies highlighted various factors, classified into nine domains: sociodemographic factors, medical history, drinking habits, eating habits, oral hygiene habits, dental factors, bruxism and temporomandibular disorders, behavioural factors, and stress. Results related to chemical TW (erosion) risk factors underline the importance of eating disorders, gastroesophageal reflux and lifestyle, particularly drinking and eating behaviours, which supports developing public health information campaigns and interventions. Besides chemical, this review identifies evidence of several mechanical TW risk factors, such as toothbrushing and bruxism; the influence of this last factor needs to be further explored.

CONCLUSIONS

TW management and prevention require a multidisciplinary approach. Dentists are in the first line to detect associated diseases such as reflux or eating disorders. Consequently, practitioners' information and guideline diffusion should be promoted, and a TW risk factors checklist (the ToWeR checklist) is proposed to help diagnostic approaches.

Erosive Tooth Wear in Subjects with Normal Occlusion: A Pioneering Longitudinal Study up to the Age of 60

The aim of this study was to assess the erosive tooth wear (ETW) at early and mature adulthood in subjects with natural normal occlusion. The sample consisted of 23 untreated subjects with normal occlusion. Dental models were taken longitudinally from the same subjects at 13 (T0), 17 (T1) and 60.9 years of age (T2) at a university. Evaluation of ETW was performed using a modified Basic Erosive Wear Examination (BEWE) index. Interphase changes were evaluated using Friedman and Dunn's test. Ordinal logistic regression was used to assess the influence of sex, dental arch, tooth and dental surfaces on the erosive tooth wear. Linear regression was used to evaluate whether the ETW degree at T1 could discriminate the degree of ETW at T2. The significance level adopted was 5%. ETW showed a significant increase with aging. The median ETW index at T0, T1 and T2 was 2, 4 and 7, respectively. ETW was greater in males in the incisors and canines and on the incisal/occlusal and lingual tooth surfaces. No significant differences were found between the maxillary and mandibular arches. Subjects with severe ETW at mature adulthood had greater tooth wear at age 17. In conclusion, ETW significantly increased during aging in subjects with normal occlusion. The greater the degree of tooth wear at early adulthood, the greater the tooth wear at mature adulthood. Preventive care should be recommended during early adulthood in patients demonstrating erosive tooth wear in order to avoid worsening with aging.

Aging changes in maxillary anterior teeth in untreated individuals: an observational longitudinal study

OBJECTIVE

The aging of the occlusion and tooth wears influence the smile design This study aimed at evaluating the aging changes of maxillary anterior teeth in nontreated subjects.

METHODS

The sample comprised dental models of 23 subjects (13 male, 10 female) with normal occlusions, taken at 13 (T1), 17 (T2) and 61 (T3) years of age. The following variables were measured in the maxillary anterior teeth using digital dental models: crown width/height proportion, anterior view width, crown angulation, gingival and incisal steps between central/lateral incisors and central incisors/canines. Interphase comparisons were evaluated using repeated measures analysis of variance followed by Tukey tests or Friedman tests. Sexual differences were evaluated using t tests (P < 0.05).

RESULTS

From 13 to 61 years of age, a decrease of crown width/height proportion (P = 0.008 and P =  < 0.001, for the lateral incisor and canines, respectively) and mesiodistal angulation (P =  < 0.001, P = 0.001 and P = 0.025 for the central incisor, lateral incisor and canines, respectively) of the maxillary anterior teeth were observed. The steps of the gingival margin and the incisal steps decreased with aging.

CONCLUSIONS

From adolescence to late adulthood, untreated individuals with normal occlusions demonstrated changes in the maxillary anterior teeth that may impair the smile esthetics and attractiveness.

The prevalence and predictive factors of dentine hypersensitivity among adults in Turkey

AIM

This study sought to determine the prevalence of dentine hypersensitivity (DH) among adults in Turkey. Also, to ascertain the association between DH and both etiological predictors and demographic patient characteristics.

MATERIAL METHOD

Using a questionnaire and thermal and evaporative tests, 259 women and 209 men in the age range of 18 to 72 were analyzed. Individually, a clinical evaluation of DH signs was conducted. The DMFT index, gingival index, and gingival bleeding were reported for each subject. The gingival recession and tooth wear of sensitive teeth were also evaluated. Pearson Chi-square test was used to compare categorical data. Logistic Regression Analysis was used to examine the risk factors of DH. Data with dependent categorical variables were compared using the McNemar-Browker test. The significance level was p < 0.05.

RESULTS

The average age of the population was 35.6 years. In the present study, a total of 12,048 teeth were analyzed. 1755 had thermal hypersensitivity (14.57%), while 470 experienced evaporative hypersensitivity (3.9%). The incisors were the teeth most impacted by DH, whereas the molars were the least affected. Exposure to cold air and sweet foods, gingival recession, and the presence of noncarious cervical lesions were all strongly linked to DH (Logistic regression analysis, p < 0.05). The cold stimulus increases sensitivity more than the evaporation stimulus.

CONCLUSION

Significant risk factors for both thermal and evaporative DH include cold air, consumption of sweet food, presence of noncarious cervical lesions, and gingival recession. More epidemiological research in this area is still required to fully characterize the risk factors and implement the most effective preventive interventions.

The Impact of Tooth Wear on the Oral Health-Related Quality of Life of the Elderly in Ibadan, Nigeria

Background

Tooth wear lesion, otherwise known as tooth surface loss, is an insidious cumulative and multifactorial condition causing irreversible destruction of tooth enamel and dentine. Over time this lesion can threaten the affected individual's Oral Health-Related Quality of Life (OHRQoL). OHRQoL entails interaction among oral health systems: social factors, psychological factors, and the rest of the body. Though, previous studies done decades ago also reported a high prevalence of tooth wear among the elderly in Nigeria, before now there has been no study on the impact of tooth wear types and severity on the OHRQoL of the elderly in this environment, which is necessary for their comprehensive management. The study was done to assess the impacts of tooth wear lesions on the Oral Health-Related Quality of Life of the elderly in Ibadan.

Methodology

It was a cross-sectional study, involving 1,200 elderly individuals. Using a multistage random sampling technique, participants were randomly selected from 2 Local Government Areas in Ibadan. Data were obtained using a structured interviewer-administered questionnaire and oral examination using the Simplified Tooth Wear Index, as well as Geriatric Oral Health Assessment Index. Data were analysed using descriptive statistics at p ≤ 0.05.

Result

Out of these elderly participants with Tooth wear lesions, 667 (55.6%) had good Oral Health-Related Quality of Life and 552 (43.5%) had poor Oral Health-Related Quality of Life. Attrition and Abfraction were the most common 1,189(99.1%) and least 5(0.4%) types of tooth wear lesions respectively. The lesions were more severe on the posterior teeth than the anterior teeth and more on the lower than the upper teeth.

Conclusion

The majority of the elderly with Tooth wear lesions had good OHRQoL, as more of them had mild to moderate grade of tooth wear.

Evolutionary and genomic perspectives of brain aging and neurodegenerative diseases

This chapter utilizes genomic concepts and evolutionary perspectives to further understand the possible links between typical brain aging and neurodegenerative diseases, focusing on the two most prevalent of these: Alzheimer's disease and Parkinson's disease. Aging is the major risk factor for these neurodegenerative diseases. Researching the evolutionary and molecular underpinnings of aging helps to reveal elements of the typical aging process that leave individuals more vulnerable to neurodegenerative pathologies. Very little is known about the prevalence and susceptibility of neurodegenerative diseases in nonhuman species, as only a few individuals have been observed with these neuropathologies. However, several studies have investigated the evolution of lifespan, which is closely connected with brain size in mammals, and insights can be drawn from these to enrich our understanding of neurodegeneration. This chapter explores the relationship between the typical aging process and the events in neurodegeneration. First, we examined how age-related processes can increase susceptibility to neurodegenerative diseases. Second, we assessed to what extent neurodegeneration is an accelerated form of aging. We found that while at the phenotypic level both neurodegenerative diseases and the typical aging process share some characteristics, at the molecular level they show some distinctions in their profiles, such as variation in genes and gene expression. Furthermore, neurodegeneration of the brain is associated with an earlier onset of cellular, molecular, and structural age-related changes. In conclusion, a more integrative view of the aging process, both from a molecular and an evolutionary perspective, may increase our understanding of neurodegenerative diseases.

Three-dimensional microscopic comparison of wear behavior between immature and mature enamel: an in vitro study

BACKGROUND

Dental enamel, the hardest outermost layer of a human tooth, is subjected to occlusal forces throughout life during different oral function as talking, mastication etc. Due to this continuous stress, wear causes the loss of this protective shell. This study aimed to detect microscopic differences in enamel's wear behavior among different age groups of adolescents and adults.

AIMS AND METHODS

Enamel specimens from immature open-apex and mature closed-apex premolars were subjected to simulated occlusal wear of impact and sliding wear test ISWT. Upper and lower enamel specimens were made to come in contact under controlled conditions. The enamel specimens' surfaces were examined using different microscopes. The upper and lower specimens were subjected to the following tests; pre-test light microscopy examination, enamel specimens' preparation for ISWT, scanning laser confocal microscopy of upper specimens, three-dimensional (3D) colored laser microscope and a Profilometer imaging of the lower specimens.

RESULTS

Wear characteristics, including wear areas, crater depths, and relation to enamel microstructures, differed among different age groups. Immature enamel from the upper specimens was more resistant to chipping than mature enamel with no statistically significant wear area difference. The immature enamel craters from the lower specimens were wider and deeper than those in the mature enamel; the wear areas in the mature enamel in the lower specimens were almost flat and smooth. The wear areas in the immature enamel in the lower specimens were significantly larger than those in the mature enamel.

CONCLUSIONS

Wear characteristics of the immature enamel are different from those of the mature enamel. Hence, it should be repaired using restorative materials with compatible wear properties.

3D segmentation of dental crown for volumetric age estimation with CBCT imaging

In adult dental age estimation, segmentation of dental volumetric information from different tooth parts using cone-beam computed tomography (CBCT) has proven beneficial in improving the regression model reliability. This segmentation method can be expanded in the crown part since the volumetric information in the crown is affected by attrition in the enamel and secondary dentine in the dentine and pulp chamber. CBCT scans from 99 patients aged between 20 and 60 were collected retrospectively. A total of 80 eligible teeth for each tooth type were used in this study. The enamel to dentine volume ratio (EDVR), pulp to dentine volume ratio (PDVR) and sex were used as independent variables to predict chronological age (CA). The EDVR was not affected by PDVR. The highest R² was calculated from the maxillary canine (R² = 0.6). The current approach in crown segmentation has proven to improve model performance in anterior maxillary teeth.

Prevalence and risk factors of erosive tooth wear among young adults in the Singapore military

OBJECTIVES

Erosive tooth wear (ETW) is defined as the irreversible chemo-mechanical loss of dental hard tissues without plaque or bacteria and has been a growing phenomenon in the general population worldwide. The aim of this study was to determine the prevalence of ETW and the associated risk factors among young military personnel in Singapore.

MATERIALS AND METHODS

This cross-sectional study consisted of a questionnaire and clinical examination of military personnel between 18 and 25 years. The questionnaire collected information on demographics, medical and dental history, lifestyle and dietary habits. Tooth wear was clinically evaluated using the Basic Erosive Wear Examination (BEWE) index. The participants were profiled into four risk categories (none, low, moderate, severe) based on the sum score. Multivariable logistic regression analysis was performed to determine the risk factors associated with the presence of ETW.

RESULTS

Out of 1296 participants evaluated, 21.8% of them had ETW. The anterior sextants were more affected by erosion than posterior sextants for both arches. The risk factors significantly associated with ETW were GERD (OR = 2.83, p = 0.041), presence of self-reported TMD symptoms (OR = 2.51, p < 0.001), acidic food (OR = 2.03, p < 0.001) and drinks (OR = 3.07, p < 0.001), high caries risk (OR = 4.59, p < 0.001) and toothbrush stiffness (OR = 4.67, p < 0.001).

CONCLUSION

ETW is prevalent among the young military population, with over half of the population at a risk of ETW. Gastric reflux disease, TMD, acidic diet, dental caries susceptibility and the use of stiff toothbrushes were identified as significant risk factors.

CLINICAL RELEVANCE

A large proportion of young military personnel exhibited mild to moderate risk of ETW. Dental professionals can identify risk-susceptible individuals at a young age and educated them with preventive measures and dietary interventions to prevent the progression of the condition.

Tooth- and Patient-Related Conditions May Influence Root Canal Treatment Indication

Aim

To investigate predisposing aspects related to the indication for root canal treatment (RCT) at Dental Schools of Brazil.

Methods

Data of 207 patients referred to endodontic treatment at undergraduate Dental Schools of Brazil were collected over a period of 8 months. Patient-related data included age, gender, first dental visit, tooth brushing frequency, number of remaining teeth, and previous endodontic treatment, and tooth-related information regarding number, type, and location in the mouth of teeth that need RCT, waiting time for the endodontic treatment, endodontic diagnosis, pain report, and dental crown condition was collected for each participant. Bivariate analysis (Chi-square test; p < 0.05) associated gender and tooth/patient-related conditions. Poisson regression analysis compared multiple endodontic need and exposure variables.

Results

Patients were mainly comprised of women (65.2%), aged 18-39 years (69.6%). Previous RCT was significantly more prevalent in women when compared to men (p=0.005). First dental visit at later moment (after 20 years of age) demonstrated 400% greater prevalence of multiple RCT demand when compared to patients that attended the dental office at age below seven years (p=0.032). Most of the patients presented only one tooth needing RCT (80.2%), mainly premolars (44.9%). Interestingly, women underwent more RCT in maxillary teeth (p=0.016) and significantly contributed with their report to the diagnosis process when compared to men (p=0.014). Regarding dental crown condition, 45.4% of all teeth registered unsatisfactory restorations, which were more pronounced in female patients (p=0.018). Unsatisfactory restorations or dental caries had 75% and 82%, respectively, less prevalence of multiple RCT indication when compared to sound dental crown (p=0.001).

Conclusions

RCT was undertaken more frequently in young female adults' premolars presenting unsatisfactory restorations. First dental visit, number of teeth with previous endodontic treatment, tooth group, and dental crown condition were significantly associated with the necessity of multiple endodontic treatments.

Tooth Age Impact on Dental Erosion Susceptibility and Treatment Efficacy

This laboratory study investigated the impact of tooth age on dental erosion susceptibility and preventive treatment efficacy. Extracted human premolars were selected and had their age estimated (∼10-100 years old) using established dental forensic methods. Enamel and root dentin slabs were prepared, embedded in acrylic blocks, flattened, and polished. The specimens were randomly assigned to one of three treatments (n = 93): Sn+F (800 ppm Sn as SnCl2 and 250 ppm F as NaF, pH 4.5), NaF (250 ppm F, pH 4.5), or deionized water (DIW). Each specimen was subjected for 10 days to a daily cycling protocol consisting of six 5-min erosive challenges (0.3% citric acid, pH 2.6), six 60-min remineralization periods (artificial saliva), and three 2-min treatments with the test solutions. Surface loss (SL) was measured after 3, 5, and 10 days, using optical profilometry. Effects of tooth age, antierosive treatment, and time on SL were evaluated using linear mixed effects regression analysis. SL increased with age for all substrate-treatment-time combinations (p < 0.0001). Sn+F and NaF solutions significantly reduced SL compared to DIW, regardless of substrate, time, or age (p < 0.0001), with best results shown for Sn+F. Efficacy of Sn+F increased with tooth age on enamel, but tooth age did not affect the efficacy of NaF on enamel. For dentin, increased efficacy was observed with age after 5 (for Sn+F) and 10 days (for Sn+F and NaF). In conclusion, increase of tooth age rendered enamel and root dentin more susceptible to dental erosion. NaF preventive efficacy improved with tooth age for dentin, in advanced erosion simulation. Sn+F reduced enamel SL due to erosion regardless of tooth age.

Common Medical and Dental Problems of Older Adults: A Narrative Review

The advancement of medicine has reduced the rate of mortality and older adult population is increasing. Among the 7,700,000,000 world population in 2019, 1 in 11 people were at the age of 65 or more. The population is expected to increase to 1 in 6 people by 2050. Older adults have degenerative changes that become more severe with age. This study used the World Health Organization’s websites and PubMed and Google Scholar databases to review current global oral and systemic health issues. Studies generally reported that many older adults have no regular dental checkup. Common oral diseases such as dental caries particularly root caries and periodontal disease are highly prevalent among them. These oral diseases are often interrelated with their systemic problems. A meta-analysis reported diabetes increases the incidence and progression of periodontitis by 86%. A decrease in salivary output is common among older adults having polypharmacy. A review reported the caries risk in older adults increases by 60% with low resting pH and low stimulated salivary flow rate. Many older adults suffer from dementia and depression which complicates the delivery of dental treatment. Proper oral hygiene practice and dental care at supine position are often difficult to be carried out if they have rheumatoid arthritis. With the increasing need of elderly dental care, dentists and other dental personnel should understand interlaced oral and general health in order to provide a successful dental care plan for older adults. The aim of this study is to give an overview of the common medical conditions and dental problems and their impacts on older adults.

Quantitative morphometric analysis of molar teeth and alveolar bone using micro-computed tomography in aged mice

OBJECTIVES

Irreversible morphological regressions of the teeth or related structures in older people can diminish their overall health. However, research on human aging in dentistry is complicated by several confounding factors. In this study, we conducted a morphometric analysis of the mandibular second molars and surrounding alveolar bone in C57BL/6 mice to evaluate age-related changes in the oral cavity.

METHODS

The animals were divided into five groups based on their age: 4 weeks (juvenile mice; n=5); 20 weeks (n=7), 50 weeks (n=5), 77 weeks (n=7), and 100 weeks (n=5); changes were evaluated using micro-computed tomography.

RESULTS

The molars of juvenile mice had sharp and pointed cusps and presented maximum heights. With age and occlusal wear, the cusp heights demonstrated a significant decrease (up to 75%) until the last stage of life. Conversely, apparent lesions were not observed on the basal portion of the crown, even in the most heavily worn teeth. The roots of the molars continued to grow in length at 4 weeks of age. Alveolar bone resorption begins to occur in middle age and continues throughout life. The proportion of vertical bone loss reached approximately 40% of the entire root length, demonstrating a remarkable increase between weeks 77 and 100.

CONCLUSIONS

Overall, these morphological changes were similar to those observed in humans. Therefore, it might be appropriate to use aged mice as an experimental model for basic and clinical research in geriatric dentistry.

Longitudinal 3D Study of Anterior Tooth Wear from Adolescence to Adulthood in Modern Humans

Simple Summary

Tooth wear is the loss of tooth substance during everyday functioning by means other than dental caries. It is expected at a certain level in every person, and it increases with age. In the last decades, due to the increased life expectancy and high patient demands, it has become an important problem modern dentistry has to face. However, the average amount of tooth wear among individuals remains controversial. The purpose of this clinical study was to precisely detect the extent of anterior tooth wear over a thirteen-year period, from adolescence to adulthood. The present study revealed the very high tooth wear occurrence in the population already at early adulthood and showed that wear monitoring at an individual level is important for dentists to enable the better understanding of the problem and allow timely targeted interventions for patients in need. These might be preventive, such as the prescription of mouth guards to limit grinding and the cessation of harmful habits that lead to tooth wear, or interceptive, such as the restoration of the lost tooth substance to stop the progress of the condition and improve esthetics and function.

Abstract

In modern humans, tooth wear can easily be observed as a loss of tooth substance, but its precise measurement is problematic. The aim of this longitudinal cohort study was to determine the precise amount of occlusal tooth wear in the anterior permanent dentition from adolescence to adulthood. Corresponding tooth crowns from serial 3D digital dental models of 72 individuals were best fit-approximated by applying novel, highly accurate 3D superimposition methods. The superimposed crowns were simultaneously sliced on intact structures, and the differences in the volumes of the subsequent occlusal parts were calculated. Over a thirteen-year period, there was an average loss of anterior occlusal surfaces of 1.58 mm³ per tooth. Tooth surface loss in at least one tooth was higher than 1 mm³ in 93.1% of the human subjects. Tooth wear severity differed by sex and tooth type, with males showing higher values versus females and upper canines versus other anterior teeth. The study revealed the endemic occurrence of occlusal anterior tooth wear, highlighting the need for monitoring of the condition in the population to identify high-risk patients and enable timely interventions. The novel methods applied here on 3D digital models are recommended for this.

Reliability of qualitative occlusal tooth wear evaluation using an intraoral scanner: A pilot study

Dental wear analysis through the use of an intraoral scanner is a reality of modern dentistry. This study aimed to investigate the reliability of qualitative tooth wear evaluation through three-dimensional images captured with an intraoral scanner and compared to clinical and photographic examinations. Eighteen adult volunteers of both genders (18 to 55 years old) were submitted to clinical exams, intraoral photographs and intraoral scanning protocol using an optical scanner (TRIOS® Pod, 3Shape, Copenhagen, Denmark). Occlusal tooth wear, from second to second premolars, was measured by two evaluators and reevaluated after 30 days, according to a slight modification of the method described by Mockers et al. Weighted Kappa was used to measure intra and inter-examiner agreement. The Friedman test was used to verify the differences among methods. Random and systematic errors were assessed using Bland-Altman plots. All statistical analysis was performed with p<0.05. There was a substantive agreement for clinical (K = 0.75) and photographic exams (K = 0.79) and a moderate agreement for intraoral scanner analysis (K = 0.60) for inter-examiner evaluation. A substantial intra-examiner agreement was obtained for both evaluators. No significant difference between the methods was observed (p = 0.7343 for examiner 1 and 0.8007 for examiner 2). The Bland-Altman plot confirmed no systematic errors between the methods and a random error of 0.25 with the scanner method when compared to clinical assessment. All three methods showed reliability in qualitative occlusal tooth wear evaluation. Intraoral scanning seems to be a sound and reliable tool to evaluate tooth wear when compared to traditional methods, considering the lower inter-examiner agreement and the inherent limitations of this pilot study. Further research will be necessary in order to achieve more robust evidence.

Design of occlusal wear facets of fixed dental prostheses driven by personalized mandibular movement

STATEMENT OF PROBLEM

Existing virtual articulators simulate mandibular movement by using various parameters and are used to design restorations. However, they are not able to reproduce actual patient movements, and the designs of occlusal wear facets by them and by personalized mandibular movement have not been compared.

PURPOSE

The purpose of this clinical study was to establish a clinical application protocol for a virtual articulator based on previous research and to evaluate the accuracy of the occlusal wear facets designed by it.

MATERIAL AND METHODS

The gypsum casts of 12 participants were scanned with a cast scanner as the original data. A single crown, 3-unit splinted crowns, a 5-unit fixed partial denture, and a fixed complete denture were virtually prepared on the digital mandibular casts by using the Geomagic Studio 2013 software program. High points were created at the wear facets, and corresponding digital wax patterns with occlusal interferences were generated. The exocad software program was used to design corresponding restorations with the copy method. Static (STA restoration) and dynamic (DYN restoration) occlusal adjustments were carried out with the built-in virtual articulator. The mandibular movements of participants were recorded by the novel virtual articulator system, and the occlusal surfaces of the digital wax patterns were adjusted (FUN restoration). The restorations adjusted with the 3 methods were compared with the original data. The mean value and root mean square (RMS) of 3D deviation and positive volumes (V+) in the occlusal direction were measured. Depending on the normality, 1-way ANOVA and the Kruskal-Wallis test were used to analyze the influence of occlusal surface design methods on the morphology of occlusal wear facets (α=.05).

RESULTS

The mean deviation of the 4 kinds of STA restorations ranged from 0.19 mm to 0.22 mm, the DYN restorations from 0.13 mm to 0.17 mm, and the FUN restorations from 0.03 mm to 0.09 mm. A significant difference was found between the STA and FUN restorations of the 3-unit splinted crowns and 5-unit fixed partial dentures (Ρ=.013, Ρ=.021). The mean values of 3D deviation and V+ decreased from the STA group to the DYN group and then to the FUN group. The RMS and V+ were statistically similar (Ρ>.05).

CONCLUSIONS

The preliminary results of the study indicate that the FUN 3-unit splinted crowns and 5-unit fixed partial dentures designed with the self-developed virtual articulator were better than the STA restorations. The FUN restorations were more coincident with the morphology of the wear facets on the original teeth.

Prevalence of erosive tooth wear in Chilean adults, 2016: A cross-sectional study

OBJECTIVES

To determine the prevalence, severity and distribution of erosive tooth wear lesions in adult patients at the Universidad de los Andes Health Center in the San Bernardo Metropolitan Region, Chile, during a period of 4 months in 2016.

METHODS

A cross-sectional study was conducted. A consecutive sample of patients from 18 to 46 years old who were receiving care at the Universidad de los Andes Health Center during a period from September 2016 to January 2017 was analysed. Basic erosive wear examinations (BEWEs) were performed by two calibrated examiners.

RESULTS

A total of 535 adults were included in this study. An erosive tooth wear prevalence of 97.9% was found in which at least one surface had a BEWE score of 2 or 3 as the highest score (98.56% for females and 95.8% for males). In the sample, 75.70% and 74.77% of individuals had at least one surface with a BEWE score of 3 at the second and fifth sextant, respectively. The median of cumulative BEWE scores was 12. The median by individual of the affected percentage of tooth surfaces with BEWE scores 2 or 3 was 19.70%.

CONCLUSIONS

We found a high prevalence of erosive tooth wear, mainly in the anterior group of teeth. No differences were found between the sexes, but a positive correlation with age was found. The percentage of surfaces affected was low or moderate.

Poor Oral Health as a Determinant of Malnutrition and Sarcopenia

Aging is accompanied by profound changes in many physiological functions, leading to a decreased ability to cope with stressors. Many changes are subtle, but can negatively affect nutrient intake, leading to overt malnutrition. Poor oral health may affect food selection and nutrient intake, leading to malnutrition and, consequently, to frailty and sarcopenia. On the other hand, it has been highlighted that sarcopenia is a whole-body process also affecting muscles dedicated to chewing and swallowing. Hence, muscle decline of these muscle groups may also have a negative impact on nutrient intake, increasing the risk for malnutrition. The interplay between oral diseases and malnutrition with frailty and sarcopenia may be explained through biological and environmental factors that are linked to the common burden of inflammation and oxidative stress. The presence of oral problems, alone or in combination with sarcopenia, may thus represent the biological substratum of the disabling cascade experienced by many frail individuals. A multimodal and multidisciplinary approach, including personalized dietary counselling and oral health care, may thus be helpful to better manage the complexity of older people. Furthermore, preventive strategies applied throughout the lifetime could help to preserve both oral and muscle function later in life. Here, we provide an overview on the relevance of poor oral health as a determinant of malnutrition and sarcopenia.

Volumetric assessment of the dental crown for sex estimation by means of cone-beam computed tomography

Sex estimation has a vital role in the solution of forensic cases when the identification of a large number of victims is needed. Considering the sexual dimorphism of the human teeth, the objective of this study was to estimate human sex by means of cone beam computed tomography (CBCT)-based volumetric assessment of the dental crown. A total of 78 CBCT images of the upper central incisors, upper and lower canines, and lower lateral incisors were equally selected from a Brazilian population aged between 8 and 36 years old. The dental crowns were subjected to image-based volumetric assessment by manual segmentation using the 3D slicer software, and the outcomes were compared by the Mann-Whitney test, unpaired t-test, Pearson correlation test, conditional backward stepwise logistic regression and intraclass correlation coefficient (α=0.05). The volumetric accuracy of the upper central incisor, upper canine and lower canine for sex estimation were 64.1%, 74.4% and 79.5%, respectively. The combined analysis of the upper and lower canines allowed an average accuracy of 83.7%. In conclusion, the combined volumetric analysis of the crown of the upper and lower canines can be applied for sex estimation in the studied population.

Clinical presentation of two phenotypes of tooth wear patients

OBJECTIVE

To assess the clinical presentation of wear lesions in two phenotypes of tooth wear (TW) patients based on distribution and morphological features of wear.

MATERIALS AND METHODS

103 patients (mean age = 43.1 years) were divided into two groups based on cluster analysis; cluster A (61 patients) and cluster B (42 patients). The distribution of wear lesions, scores of presence or absence of 10 defined morphological TW criteria and number of teeth fulfilling each criteria were compared between groups. Intra- and inter-examiner reliability of the 10 TW criteria was determined by Cohen's kappa and intraclass correlation coefficient.

RESULTS

While cluster A had more wear in maxillary anterior teeth and mandibular molars compared with the same opposing tooth groups (p < 0.001, p < 0.007 respectively), there were no differences for cluster B. Cluster A was characterized by higher prevalence of 4 chemical morphological criteria and the highest number of teeth affected by one chemical criteria, whereas cluster B had a higher prevalence of one mechanical criteria and higher number of teeth affected by an additional mechanical criteria. Both intra- and inter-examiner values for the defined TW criteria were fair to excellent.

CONCLUSION

The results may indicate a more chemical background for TW in cluster A and mechanical background in cluster B. Furthermore, clinicians may use certain clinical features of TW to distinguish between individuals who belong to a specific TW cluster with a presumed chemical or mechanical etiology. These preliminary findings need to be confirmed in future studies.

A survey on the prevalence and risk indicators of erosive tooth wear among adolescents in Guangzhou, South China

BACKGROUND

Erosive tooth wear (ETW) has become a crucial oral health problem over the decades in China.

OBJECTIVES

To explore the prevalence and risk indicators of ETW among adolescents in Guangzhou, south China.

METHODS

A cross-sectional survey of 720 participants was conducted in Guangzhou, using an equal-sized, stratified, multistage random sampling approach. The participants were from two different age groups (12- and 15-year-olds), 360 per group. The ratio of males to females was 1:1 in each group. ETW was recorded utilising the basic erosive wear examination (BEWE) index as the dependent variable. Independent variables included age, gender, region, socioeconomic status, dietary factors, oral health measures and others.

RESULTS

The prevalence rates (weighted) of ETW and dentin exposure (DE) were 56.1% and 26.2% among adolescents in Guangzhou, with mean teeth (weighted) of 1.8 ± 2.5 and 0.6 ± 1.5, respectively. No matter the prevalence or the mean teeth, the 15-year-olds were higher than the 12-year-olds; the mean teeth of ETW of males was higher than that of females; the mean teeth of ETW and DE of the adolescents of low socioeconomic status were higher than those of high socioeconomic status. Medium to high risk levels were found for 10.1%. In the multiple regression model, age, gender and taking acidic foods/drinks before sleep were associated with ETW.

CONCLUSIONS

Moderate ETW in the permanent dentition was common among adolescents in Guangzhou. However, the teeth involved were low. Dietary factors and demographics were the main risk indicators.

The Prevalence and Severity of Tooth Wear in Type 2 Diabetic Patients

Objective

To assess the prevalence and severity of tooth wear in type 2 diabetic patients.

Methods

Attendees at a diabetic clinic at Wiang Pa Pao Hospital in Chiang Rai province, Thailand, were invited to take part in this cross-sectional study. All participants were aged 35–74 and had type 2 diabetes. Participants were required to have been diagnosed with diabetes for at least three months. 179 subjects accepted a clinical oral examination and completed the questionnaire. Tooth wear was assessed clinically using the Smith and Knight Tooth Wear Index.

Results

The mean age of diabetic patients was 56.5 ± 7.8 years. The majority (44.1%) had diabetes more than 5 years. The average years of having had diabetes was 6.5 ± 6.3 years. The most prevalent type of tooth wear was attrition (99.4%). The prevalence of erosion, abrasion, and abfraction were 64.8%, 31.3%, and 7.3%, respectively. The majority of the tooth wear was moderate to high severity (62.1%). Erosion and abfraction showed significant association with age group (p < 0.05). Age group was significantly associated with the severity level (p=0.017). Mild tooth wear severity was the highest in age groups 35–44 and 45–54 (53.8% and 41.2%, respectively). Moderate tooth wear was the highest proportion in age groups 55–65 and 65–74 (52.2% and 44.0%, respectively). There were no significant differences between specific diabetic symptoms and types of tooth wear.

Conclusion

There was a high prevalence of tooth wear among diabetic patients. The role of prevention is vital in maintaining the integrity of the teeth and to avoid treating these worn teeth in diabetic patients.

Prevalence, severity and explanatory factors of tooth wear in Arab populations

OBJECTIVES

The aim of this study was to assess the prevalence and severity of tooth wear and related risk indicators in six Arab countries.

METHODS

This multicenter, multinational cross-sectional study was conducted among 2924 participants between the ages of 18-35 years old from six Arab countries. Calibrated dentists assessed tooth wear using the Basic Erosive Wear Examination Index (BEWE). Participants were also asked to complete a questionnaire that assessed their dietary and oral health habits. Each participant was identified by the sextant with the highest BEWE score in the upper and lower jaws.

RESULTS

Odds ratios were estimated for correlates of tooth wear anterior and posterior regions. Oman had the highest prevalence of BEWE score 3 (N = 255 (60.2%)). Overall, the highest BEWE score 3 was observed on the incisal edge of the upper anterior teeth (N = 602 (20.6%)) and in the lower left posterior region (sextant 6) on the occlusal surface (N = 466 (15.9%)). Correlates of severe tooth wear in both regions were eating or drinking more than six times per day, age and education. Drinking soft drinks "once a day" was significantly associated with severe tooth wear in the posterior region (OR: 1.3, 95% CI:1.05, 1.6). Brushing teeth more than twice a day was inversely associated with tooth wear in the anterior region (OR:0.75, 95% CI: 0.57,0.97).

CONCLUSION

The prevalence of tooth wear in Arab populations is relatively high, specific preventive and therapeutic measures should be developed to target people at higher risk of this condition.

CLINICAL SIGNIFICANCE

Tooth wear is now regarded as a significant oral health problems, dentists should advise their patients about dietary and oral health habits that can lead to severe tooth wear.

Associated factors to cervical dentin hypersensitivity in adults: a transversal study

Background

This cross-sectional study aimed to identify the factors associated to the cervical dentin hypersensitivity (DH) in Brazilian adult population.

Methods

Three hundred and eighty patients (67.2% women and 32.8% men) were assessed by questionnaire and thermal test with ice. Participants marked in a visual analogue scale (VAS) the intensity of pain, and a calibrated examiner (ICC 0.990) measured the scores using a caliper. Pain scores above 0.5 mm were considered sensitive teeth. The DH associated factors were investigated by clinical examination. The association between variables was assessed by Spearman correlation and the Chi-square test. Logistic regression was used to determine the variables that predict DH (p < 0.05).

Results

The mean age of participants was 24.08 years. In this population, 8958 teeth were evaluated, of those 3037 (33.9%) were diagnosed sensitive. The most prevalent associated factors to DH were abnormal tooth positioning (9.0%), occlusal trauma (6.5%) and gingival recession (5.6%). The erosion predicted significantly the DH on both simple (OR 7.85, p < 0.001) and multiple(OR 4.36, p < 0.001) analysis.

Conclusion

The exposure of dentinal tubules by erosion is probably the major predictor of dentin hypersensitivity. The healthy tooth is able to protect against DH.

Tooth wear and gingival recession in 210 orthodontically treated patients: a retrospective cohort study

Aim

To assess the association between tooth wear (TW) and gingival recession (GR).

Materials and Methods

Two hundred and ten orthodontically treated participants (100 males) were evaluated. GR and TW were rated independently by four raters on plaster models at four time points: before treatment (T1), mean age 13.8 years (SD = 3.7); after treatment (T2), mean age 16.7 years (SD = 3.9); 3 years after treatment (T3), mean age 19.7 years (SD = 4.2); and 7 years after treatment (T4), mean age 23.9 years (SD = 4.8). Univariable and mulitvariable random effects logistic regression analyses were performed with scores for GR as dependent variables and with TW, age, gender, dental segments (maxillary and mandibular anterior and posterior segments), time points, and Angle classification as independent variables. Method reliability was assessed with kappa statistics.

Results

Mandibular incisors, mandibular and maxillary first premolars and maxillary first molars were most vulnerable to GR. The prevalence of GR increased during the observation period. At T1 20.5% participants had one or more recession sites, at T4 85.7 % of the participants had at least one GR. There was evidence of association between moderate/severe TW and GR-for a tooth with moderate/severe wear, the odds of recession were 23% higher compared to a tooth with no/mild wear (odds ratio 1.23; 95% CI: 1.08-1.40; P = 0.002). Age, dental segment, and time were also significant recession predictors, whereas gender was not.

Conclusions

There is evidence that moderate/severe TW is associated with the presence of gingival recession. Clinical significance of this can be limited.

Trend-analysis of dental hard-tissue conditions as function of tooth age

OBJECTIVE

This retrospective in-vitro study investigated tooth age effect on dental hard-tissue conditions.

METHODS

Unidentified extracted premolars (n = 1500) were collected and their individual age was estimated (10-100 (±10) years old (yo)) using established dental forensic methods Dental caries, fluorosis and tooth wear (TW) were assessed using the International Caries Detection and Assessment System (ICDAS; 0-5 for crown and 0-2 for root), Thylstrup-Fejerskov (TFI; 0-9) and Basic Erosive Wear Examination (BEWE; 0-3) indices, respectively. Staining and color were assessed using the modified-Lobene (MLI) (0-3) and VITA shade (B1-C4) indices, respectively. Relationships between indices and age were tested using regression models.

RESULTS

Starting at age ∼10yo, presence of caries increased from 35% to 90% at ∼50yo (coronal), and from 0% to 35% at ∼80yo (root). Caries severity increased from ICDAS 0.5 to 2 at ∼40yo and from ICDAS 0 to 0.5 at ∼60yo for coronal and root caries, respectively. Presence of TW increased from 25% (occlusal) and 15% (smooth-surfaces) to 100% at ∼80yo. TW severity increased from BEWE 0.5 to 2 at ∼50yo (occlusal) and ∼0.3 to 1.5 at ∼50yo (smooth-surfaces). Percentage and severity of fluorosis decreased from 70% to 10% at ∼80yo, and from TFI 1 to 0 at ∼90yo, respectively. Percentage of extrinsic staining increased from 0% to 85% at ∼80yo and its severity increased from MLI 0 to 2 at ∼70yo. Color changed from A3 to B3 at ∼50yo (crown), and from C2 to A4 at ∼85yo (root).

CONCLUSIONS

Aging is proportionally related to the severity of caries, TW, staining, and inversely to dental fluorosis. Teeth become darker with age.

Deformation behaviour of aged coronal dentin

OBJECTIVE

This study aimed to identify the changes in the time-dependent deformation response of coronal dentin with ageing and its relationship with changes in chemical composition.

BACKGROUND

The structural behaviour of dentin with ageing is affected by changes in the density and diameter of its dentinal tubules (ie porosity), as well as changes in chemical composition throughout the tooth. However, little is known about the time-dependent deformation behaviour of aged dentin and the importance of its hierarchical structure and variations in chemical composition.

MATERIALS AND METHODS

The spherical indentation response of aged coronal dentin was analysed in the outer, middle and inner regions, and its time-dependent deformation response was modelled in terms of its microstructure and chemical composition using a model recently proposed for young dentin.

RESULTS

The viscous deformation behaviour of aged dentin followed a power-law response with a decrease in the stress exponent when compared to young dentin. These results can be explained by cross-linking of the collagen present in the tissue.

CONCLUSION

A decrease in the deformation ability of aged dentin was found. This behaviour could be a result of a dissolution process and reprecipitation of the minerals present in intertubular dentin into the dentinal tubules.

Age assessment in canine and premolar by cervical axial sections of cone-beam computed tomography

Age estimation in adults is a challenge in both anthropological and forensic situations compared to sub-adults age estimation. The present study explored, for the first time, the cervical zone of single rooted teeth. The deposition of secondary dentin is responsible for a decrease in the volume of the dental pulp cavity with aging, and therefore is often used as an age indicator. The current study aimed at estimating the chronological age among adults by measuring the pulp/dentin area ratio (physiological ratio) by axial sections at cervical region of maxillary canine and mandibular second premolar. The sample consisted of 120 cone beam CT images of 120 Tunisians whose age ranged from 22 to 67, from the database of a private clinic of radiology. The first axial section of chosen teeth without enamel was selected. Linear regression models were derived for canine, premolar and for all variables to predict the age. They indicated that dentin deposition on canine and premolar have almost the same correlation with age (r=-0.838 and -0.837 respectively). The residual standard errors (RSE), when these regression equations applied for the entire sample, were ranged between 8.27, 8.29 and 7.06 for canine, premolar and for all variables respectively. Tested for younger ages (from 22 to 44years) the RSE decreased considerably and thus ranged between 4.32, 4.72 and 4.05. The outcomes of this study show that the physiological ratio is a useful variable for assessing age with a satisfying accuracy.

Tooth wear: a cross-sectional investigation of the prevalence and risk factors in Beijing, China

Objectives:

The aim of this study was to evaluate the epidemiology of tooth wear in Beijing and to establish appropriate preventive measures.

Materials and Methods:

This cross-sectional analysis involved a questionnaire survey conducted for 1,812 individuals aged 12–74 years in Beijing. Subjects were local residents living in the region for >6 months before the survey. Subjects were evaluated using clinical examinations with the basic erosive wear examination index and a self-administered questionnaire. Statistical analyses were performed using SPSS software.

Results:

The prevalence of maxillary tooth wear was 84.9% for the molars, 68.9% for the premolars, 74.1% for the canines and 97% for the incisors. In the mandible, the corresponding prevalence rates were 85.2%, 59.3%, 78.6% and 97.4%, respectively. The occlusal, incisal and cervical surfaces showed more frequent wear compared with the other surfaces. Age, acidic beverages, xerostomia and brushing habits were identified as risk factors for tooth wear (P<0.05).

Conclusions:

Tooth wear is common in Beijing. Specific preventive measures should be recommended for individuals reporting excessive consumption of fruits and/or acidic beverages, and those with xerostomia. In particular, incisor wear should be carefully monitored in individuals of all age groups.

Restoration of the Occlusal Vertical Dimension with an Overlay Removable Partial Denture: A Clinical Report

The process of tooth loss throughout life associated with severe occlusal wear may pose a challenge in the rehabilitation of partially edentulous arches. In these cases, many therapeutic procedures are necessary because each tooth must be restored to obtain the correct anatomical contour and recover the occlusal vertical dimension (OVD). A removable partial denture (RPD) with occlusal/incisal coverage, also known as an overlay RPD, is an alternative treatment option with fewer interventions, and, consequently, lower cost. This clinical report reviews the principles involved in the clinical indication for an overlay RPD, as well as the necessary planning and execution, to discuss the feasibility and clinical effectiveness of this treatment, identifying the indications, advantages, and disadvantages of this procedure through the presentation of a clinical case. The overlay RPD can be an alternative treatment for special situations involving partially edentulous arches in patients who need reestablishment of the OVD and/or realignment of the occlusal plane, and it can be used as a temporary or definitive treatment. The main advantages of this type of treatment are its simplicity, reversibility, and relatively low cost; however, further studies are needed to ensure the efficacy of this treatment option.

Prevalence and Indicators of Tooth Wear among Chinese Adults

Numerous epidemiological studies have focused on the prevalence and related indicators of tooth wear. However, no sufficient studies have been conducted with Chinese adults. The purpose of this study was to assess the prevalence of tooth wear and identify related indicators among adults aged 36 to 74 years in Wuhan City, P.R. China. A cross-sectional and analytic study was conducted with 720 participants, aged 35–49 yrs and 50–74 yrs, in 2014. Each age group included 360 participants, of which 50% were males and 50% were females. All participants completed a questionnaire before examination. Tooth wear was assessed using the modified Basic Erosive Wear Examination (BEWE) index. The data were analyzed using the chi-square test and binary logistic regression analysis. The prevalence of tooth wear was 67.5% and 100% in the 35–49 and 50–74 age groups, respectively. The prevalence of dentin exposure was 64.7% and 98.3%, respectively. A significantly higher prevalence of tooth wear and dentin exposure was found in the 50–74 yr group than in the 35–49 yr group (p < 0.05). Critical indicators of tooth wear and dentin exposure included high frequency of acidic drinks and foods consumption, low socio-economic status, and unilateral chewing. The frequency of changing toothbrushes and the habit of drinking water during meals were associated with tooth wear. In addition, the usage of hard-bristle toothbrushes and consuming vitamin C and aspirin were found to be linked with dentin exposure. In conclusion, the prevalence of tooth wear and dentin exposure observed in Chinese adults was high, and the results revealed an association between tooth wear and socio-behavioral risk indicators.

Restoration Survival: Revisiting Patients' Risk Factors Through a Systematic Literature Review

A literature review was conducted to investigate the influence of patient-related factors on restoration survival in posterior permanent teeth as well as to report the methods used to collect these factors. The selection of articles on longitudinal clinical studies investigating the survival of posterior restorations (except full crowns and temporary fillings) and including patient-related factors was performed by applying predefined criteria. The review was organized into two parts, the first describing how patient factors were assessed in the studies (n=45) and the second presenting the statistical significance (n=27) and size of the effect (n=11) of these factors on restoration survival. Patient-related factors mentioned in the studies included age; gender; caries risk; caries activity/severity; decayed, missing, filled teeth; number of restorations; oral hygiene; and bruxism, among others. Sixteen studies included the patient age or age range in the analysis, which was found to be significant in 47% of the studies. Regarding gender, four of 17 reports found a significant effect on survival, showing more failures for men in three studies. The caries risk profile or related variables were included in the analysis of 15 studies, and a significant effect on survival was reported for high-caries-risk individuals (or related variables) in 67% of these studies. Bruxism was also found to influence restoration survival in three of six studies where this variable was investigated. Some issues were found regarding the reporting of methods used to classify patients according to risk and were thoroughly discussed. In view of the information gathered in this review, the assessment of patient factors along with other variables should become part of clinical studies investigating restoration survival, since several of these factors were shown to influence the failure of restorations, regardless of the material type.

The prevalence and risk indicators of tooth wear in 12- and 15-year-old adolescents in Central China

BACKGROUND

Tooth wear has been investigated in numerous countries, and the prevalence has varied. However, the data on tooth wear in China are scarce. The aim of this study was to describe the prevalence of tooth wear and to investigate the relative indicators associated with tooth wear in 12- and 15-year-old adolescents in Wuhan City, Hubei Province, Central China.

METHODS

A cross-sectional descriptive study was undertaken among 720 adolescents in Hubei Province, Central China. The age groups in this study were 12- and 15-year-old, and each group consisted of 360 participants in which females and males represented 50 % each. A modified version of the Basic Erosive Wear Examination (BEWE) tooth wear index was used for the buccal, cervical, occlusal/incisal and lingual surfaces of all of the teeth in the 720 adolescents. All of the participants were asked to answer a questionnaire consisting of questions about their current and historical dietary habits and oral hygiene.

RESULTS

The prevalence of tooth wear was 18.6 and 89.4 % in 12- and 15-year-old adolescents, respectively. The prevalence rates of dentin exposure were 1.9 and 5.6 %, respectively. A significantly higher prevalence of tooth wear and dentin exposure in 15-year-old adolescents was found than in 12-year-old adolescents (p < 0.001 and p = 0.011). Several factors such as drinking soft drinks and fruit juices immediately after sports, taking aspirin, reflux, unilateral chewing, tooth brushing once daily or less often, duration of brushing less than 2 min and swimming in the summer were found to be associated with tooth wear.

CONCLUSIONS

Tooth wear in 12- and 15-year-old adolescents in Central China is a significant problem and should receive greater attention. The prevalence of tooth wear increases with age and associated with socio-behavioral risk factors.

Age estimation based on pulp chamber volume of first molars from cone-beam computed tomography images

AIM

To establish a method that can be used for human age estimation on the basis of pulp chamber volume of first molars and to identify whether the method is good enough for age estimation in real human cases.

MATERIALS AND METHODS

CBCT images of 373 maxillary first molars and 372 mandibular first molars were collected to establish the mathematical model from 190 female and 213 male patients whose age between 12 and 69 years old. The inclusion criteria of the first molars were: no caries, no excessive tooth wear, no dental restorations, no artifacts due to metal restorative materials present in adjacent teeth, and no pulpal calcification. All the CBCT images were acquired with a CBCT unit NewTom VG (Quantitative Radiology, Verona, Italy) and reconstructed with a voxel-size of 0.15mm. The images were subsequently exported as DICOM data sets and imported into an open source 3D image semi-automatic segmenting and voxel-counting software ITK-SNAP 2.4 for the calculation of pulp chamber volumes. A logarithmic regression analysis was conducted with age as dependent variable and pulp chamber volume as independent variables to establish a mathematical model for the human age estimation. To identify the precision and accuracy of the model for human age estimation, another 104 maxillary first molars and 103 mandibular first molars from 55 female and 57 male patients whose age between 12 and 67 years old were collected, too. Mean absolute error and root mean square error between the actual age and estimated age were used to determine the precision and accuracy of the mathematical model. The study was approved by the Institutional Review Board of Peking University School and Hospital of Stomatology.

RESULTS

A mathematical model was suggested for: AGE=117.691-26.442×ln (pulp chamber volume). The regression was statistically significant (p=0.000<0.01). The coefficient of determination (R(2)) was 0.564. There is a mean absolute error of 8.122 and root mean square error of 5.603 between the actual age and estimated age for all the tested teeth.

CONCLUSION

The pulp chamber volume of first molar is a useful index for the estimation of human age with reasonable precision and accuracy.