Tooth Wear Research Articles

THE IMPACT OF STRESS DURING THE COVID-19 PANDEMIC ON THE DENTAL HEALTH OF MU-VARNA EMPLOYEES

Introduction: One of the negative manifestations of stress and anxiety related to dental health is the unconscious clenching or grinding of teeth, which gradually leads to tooth wear. Aim: The aim of this article is to determine the impact of the COVID-19 pandemic on the dental health of MU-Varna employees, to follow up on the therapeutic effect of wearing a bruxism mouthguard, and for the results to be applied in preparing a model for health promotion based on a multidisciplinary approach. Materials and Methods: From July 2022 to now, 995 patients have been examined, and 40 of them, university lecturers and administrative staff at MU-Varna, Bulgaria, have been prescribed a bruxism mouthguard. The following instruments were used: a unified form for defining the dental status and a survey about the therapeutic effect of the bruxism mouthguard. Results and Discussion: A voluntary, anonymous survey was conducted among MU-Varna employees in October 2023. The SPSS (version 22) software was used to process the data from the survey. The assessment of the therapeutic effect of the mouth guard was based on the results from the secondary exam at the clinician’s office and those from the conducted individual survey among the people wearing mouth guards for a specified period of time. Conclusion: The analysis indicates that the employees have a positive attitude toward wearing the mouthguard in the future. Its use helped decrease the frequency of conditions such as affect, anxiety, and quick tiredness.

Designing mouthwash formulations with innovative molecular components to control initial dental erosion in vivo.

This study aimed to examine and compare the efficacy of mouthwashes containing different proteins and peptide on the prevention of enamel erosion in vivo, as well as to evaluate the participants' satisfaction with the formulations. Twelve participants were selected and underwent five cross-over mouthwash phases: Water (control); 0.1mg/mL CaneCPI-5; 0.5mg/mL MaquiCPI-3; 0.1mg/mL CsinCPI-2; and 0.037mg/mL Stn15pSpS. After prophylaxis, the participants rinsed (1min), followed by the acquired enamel pellicle (AEP) formation (2h). An erosive challenge was made (biopsy, citric acid 1%, 15s) on the buccal surface of the central maxillary incisors. The Relative Surface Reflection Intensity (%SRI) was assessed and analyzed by ANOVA/Tukey's tests. The calcium release in acid was measured by the Arsenazo method and verified by Kruskal-Wallis/Dunn's tests. The Spearman's correlation was used between analyses. A questionnaire evaluated the satisfaction of participants. For both analyses, the results showed that mouthwashes containing the proteins or peptide were significantly more effective in preventing enamel erosion compared to deionized water, with no significant differences among the active ingredients (p < 0.05). Also, there was a significant negative correlation between %SRI and calcium released (r=-0.5754). The questionnaire revealed that the volunteers were satisfied with the taste of the products. In addition, the experimental procedures were well tolerable, and no side effects were reported. All mouthwashes containing proteins or peptide were acceptable and effective in protecting enamel against initial dental erosion in vivo. This study highlights the potential of these pioneer organic components for the development of mouthwashes designed for people with risk of erosive tooth wear.

Relationship between tooth macrowear and jaw morphofunctional traits in representative hypercarnivores.

The mammalian adult dentition is a non-renewable resource. Tooth attrition and disease must be accommodated by individuals using behavioral, physiological, and/or musculoskeletal shifts to minimize impact on masticatory performance. From a biomechanical perspective, the musculoskeletal system becomes less efficient at producing bite force for a given amount of muscle input force over an individual's life, because tooth-food contact area increases as cusps wear. In this study we ask the question: does mandibular biomechanical performance show evidence of compensation with increasing tooth wear? We use representative taxa of three carnivoran ecomorphologies (meat specialist, scavenger, bone cracker) as a study system to compare morphofunctional data on tooth macrowear, jaw depth, bite mechanical efficiency, and jaw stress during biting. No significant shifts in adult mandibular corpus dimensions occurs in the sampled taxa as canine and carnassial teeth wear. In bone cracking spotted hyenas carnassial biting mechanical efficiency increases significantly with increasing tooth wear, with no significant change in mandibular stress. Analyses of the fossil carnivore Hyaenodon suggests an increase in canine biting efficiency with increased tooth wear, but this may reflect interspecific variation or phylogenetic contingency rather than a life history shift. Overall, these findings indicate that scavenging hyaenids and felid meat specialists do not exhibit morphofunctional compensation for the decreased mechanical capability of worn and dull teeth. Behavioral modifications, rather than musculoskeletal adjustments, may instead play a major role in maintaining food acquisition and processing capabilities for individuals surviving into advanced ontogenetic age and tooth wear. These observations highlight the mammalian masticatory system as having a dynamic performance profile through its useful lifespan, and encourage a more nuanced understanding of past and present carnivore guilds by considering wear-dependent performance changes as a possible source of selection.

Success and Survival of Composite Resin Restorations for the Management of Localized Anterior Tooth Wear: A Systematic Review and Meta-Analysis.

To systematically review the literature and assess the success and survival rates of anterior composite restorations used in the management of anterior tooth surface loss, and to estimate complete posterior occlusion re-establishment when a Dahl approach is utilized. An electronic search was performed in the following databases: MEDLINE via Ovid and Scopus, for articles published from 1970 to November 2020. The systematic review was performed according to the PRISMA and Meta-analyses guidelines. Only randomized and non-randomized clinical trials, and Cohort studies that involved the exclusive use of direct/indirect anterior composite restorations for the management of localized anterior tooth wear were included. From the 724 studies identified through the initial search, six studies fulfilled the inclusion criteria and were included in the review; three prospective and three retrospective. In total, 141 patients received 1068 direct and indirect composite restorations. Follow-up periods ranged between 5 months and 10 years. The survival rate for anterior composite resin restorations reported in this review was 88% (95% CI: 70% to 98%) over a period of 2 and 10 years; however, high heterogeneity was observed amongst included studies; (I² = 97%). Sensitivity analysis reported survival rates of these restorations of 93% (95% CI: 85% to 98%) over a period of 2 and 7 years, (I² = 83%). Success rates were reported for these restorations of 68% (95% CI: 44% to 87%) over a period of 2 and 10 years, high heterogeneity; (I² = 98%). The success of composite Dahl in re-establishing posterior occlusion was 85% (CI: 73% to 94%). The result of this systematic review and meta-analysis support the use of anterior composite restorations as a short-medium term option for the management of tooth wear. In the long-term, patients should be informed that these restorations will require monitoring, repairs, or replacements.

Productive and morphological features of females and calves of domestic deer of the Evenk and Nenets breeds during the calving period

Purpose: to conduct a comparative description of the productive and morphological characteristics of domestic reindeer of the Nenets and Evenki breeds.Materials and methods. Study of the morphological, behavioral and reproductive characteristics of domestic reindeer of the Nenets and Evenki breeds, kept in various natural and climatic conditions of the tundra and northern taiga, during the calving and dairy periods. Experimental data were collected from clinically healthy animals. The research was carried out in accordance with the basic methods of zootechnical research (observation, examination). Their gender (visually) and age were determined (using ear tags and animal registration data, and, if necessary, based on the degree of tooth wear); An assessment of the exterior of the reindeer herd was carried out before the rut to select males and females for mating. Methods of visual assessment, linear measurements of animals, and field chronometry of calving were used.Results. The Evenki breed of deer is distinguished by its large size, height, high load-carrying capacity and endurance when transporting goods and people. It has been established that the dynamics of calving of domestic reindeer of the Evenki breed is identical to the dynamics of calving of Nenets reindeer, but there are some peculiarities. In the tundra zone, calving takes 3—5 days longer, and the initial phase begins (on average) 7-10 days earlier than in the taiga zone. The live weight of Evenki breed calves at birth is 0.8 kg higher than that of Nenets breed calves. The intensity of growth up to 3 months of age is higher in the early, mass and late periods of calving. It has been established that calves of the early calving period exceed in live weight at birth and its growth the calves of the mass period, and those, in turn, exceed the calves of the late calving period. This pattern can be traced up to 6 months of age. Calves of early and mass calving periods, having the potential for rapid growth, find themselves in more favorable nutritional conditions in the first months of life than late calves. This is expressed in the ability to receive green pasture food 15-25 days earlier and be stronger by the time the blood-sucking dipterous insects appear. Early calving Nenets calves are more active at night, since there is still a lot of snow in the tundra zone during this period and the temperature sometimes drops below 0ºC.

Exploring the mechanical and biological properties of a resin-ceramic composite with biomimetic nacre structure containing zinc used for prosthodontics

Enhancement of the mechanical and biological properties of dental restoration materials is of significant importance. Drawing inspiration from the architecture and mechanical properties of natural nacre, we employed a low-cost accumulative rolling process to develop resin-ceramic composites with suitable hardness and high toughness. Plate-like aluminum oxide powder with diameters of 5–10 μm and nano-zinc oxide (ZnO) with antibacterial properties were mixed as the ceramic phase of the composite. Aluminum oxide ceramic plates were stacked using an accumulative rolling process to achieve a consistent orientation, followed by sintering to obtain porous ceramic scaffolds. The ceramic scaffolds were subsequently immersed in methyl methacrylate resin to complete the fabrication of the biomimetic composites. The mechanical and biological properties of the composites were comprehensively tested. The composites had a suitable hardness (1.09–1.63 GPa), excellent flexural strength (156.7–167.8 MPa), and fracture toughness (KIC = 2.66–3.59 MPa m1/2). Biomimetic composites are expected to mitigate the wear of natural teeth without developing fractures or deformations, while also exhibiting excellent cytocompatibility and antibacterial activity. This study investigated the factors influencing crack propagation in fracture tests and provided insights into enhancing the toughness of dental restorative materials. The biomimetic resin-ceramic composites containing Zn developed in this study have the potential to be used as functional dental restoration materials.

Strengthening Study on Microsphere Particle Peening for Flexspline Surface of Harmonic Reducer

Abstract The service stability of the flexspline directly affects the service life of the harmonic reducer. Its main failure modes are fatigue fracture of the flexspline, damage of the flexible bearing, tooth wear or transmission slip, the above problems are often sprouted and developed from the surface. Researches show the novel surface treatment technology-Microsphere Particle Peening can significantly enhance the surface performance of the flexspline of the harmonic reducer, and thus improve its fatigue resistance. Therefore, studying this novel shot peening technology has significant scientific significance and practical value. In this paper, Microsphere Particle Peening is adopted to strength the flexspline surface and the effects of three different Microsphere Particle Peening conditions on the surface performance of the flexspline is analyzed. The research results indicate that Microsphere Particle Peening technology can introduce larger residual compressive stress, reduce the surface roughness, increase the surface hardness, improve the microstructure morphology, and effectively control the deformation amount of the flexspline by controlling the processing parameters of Microsphere Particle Peening. Therefore, Microsphere Particle Peening technology has broad engineering application prospects in the surface strengthening of precision components.

Wear and abnormal fracture failure mechanisms of alloy teeth in TBM insert tooth disc cutters

Wear and abnormal fracture failure mechanisms of alloy teeth in TBM insert tooth disc cutters

A fuzzy control based strategy for adjusting band blade feed rate in constant power sawing

Abstract The variable cross-sectional shape of the blank reduces the efficiency of the sawing machine. Additionally, the wear of the band saw blade causes a mismatch between the feed rate and the load, further exacerbating the wear. This study studied a feed rate control strategy considering sawtooth wear to balance the relationship between cutting efficiency and band life. Initially, speed parameters for the cut-in and cut-out areas, along with acceleration and deceleration control algorithms, were established to ensure the smooth transition of the saw blade during the machining process. Additionally, a constant power sawing feed rate model that considers the influence of wear was developed, enabling dynamic adjustments to the feed rate based on the saw blade's wear state. This study also proposes a fuzzy control-based target current correction method, which dynamically adjusts the target current according to the current wear state of the saw blade, ensuring that sawing requirements were met under varying levels of wear. The accuracy of the sawing model and control strategy was verified through experiments. The results demonstrated that this strategy improved efficiency by 44% compared to the traditional uniform feed rate method. This study introduces a novel feed rate control strategy for sawing and offers an effective solution to the problem of saw tooth wear.

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.

Variation in white‐tailed and mule deer dental metrics is associated with precipitation gradients in the Americas

AbstractInvestigating the relationship between the physical environment and organismal adaptation is crucial to understanding the selective pressures that drive mammalian evolution. Of the varied approaches to exploring this relationship, macroscopic tooth wear analyses have become widely used due to their economic and simple methodologies. However, more work is needed to understand how assessments of wear patterns operate within finer levels of dietary and environmental contexts. It is specifically unclear if and how tooth wear differs inter‐ and intraspecifically between geographically widespread, large‐bodied mammalian populations. This project characterizes molar hypsodonty indices and mesowear scores of white‐tailed deer (Odocoileus virginianus) and mule deer (Odocoileus hemionus) populations across North and Central America, investigating if and how molar wear and morphology vary over the deer's large and ecologically variable geographic distribution. While mesowear scores generally do not strongly track environmental signals within and between Odocoileus species, hypsodonty indices reveal a strong correlation between crown height and aridity, which likely represents an adaptive response to abrasive diets in areas with low precipitation.

Investigation on meshing characteristics of spiral bevel gear under wear fault evolution with assembly errors

Spiral bevel gears have the advantage of transmitting high torque and power comparing to helical gear and straight bevel gear. However, they are susceptible to wear due to factors such as high loads, poor lubrication, and surface imperfections resulting from machining. In this study, we propose an autonomous model for predicting tooth wear and analyze the meshing characteristics of spiral bevel gear (SBG) pairs under different assembly errors. Concurrently, we establish a finite element model to validate the accuracy of our meshing characteristic analyses. We also compare the distribution patterns of wear depth on the tooth surface with existing literature. Our investigation delves into meshing characteristics, encompassing transmission errors and Time-varying mesh stiffness (TVMS), considering wear evolution under assembly errors. The results demonstrate that the fluctuations in TVMS remain consistent across all four types of assembly errors examined. Gear tooth wear leads to an increase in gear backlash and fluctuations in unloaded transmission error. The meshing stiffness fluctuation of the SBG pair enlarges under wear evolution. Assembly errors result in shifts in the initial contact line and contact pattern, subsequently altering the distribution of wear depth. Different forms of assembly errors may cause a similar effect on the distribution of wear depth and meshing characteristics.

Development and content validation of the Childhood Early Oral Aging Syndrome (CEOAS) index for the deciduous dentition: Research protocol.

Premature, non-physiological tooth wear in childhood has numerous repercussions for oral health. This is a growing problem with multifactorial causes and associated with the current lifestyle. The introduction of new concepts and indices is crucial for enhancing the understanding and management of dental conditions. In this context, we present the Childhood Early Oral Aging Syndrome (CEOAS) and the associated index, which aim to assess early enamel wear in the primary dentition. Rather than focusing solely on isolated etiologies, the index proposes a comprehensive evaluation of signs and symptoms, considering various factors that contribute to the premature and non-physiological loss of dental structure, including wear of both intact and hypomineralized enamel. Indices that evaluate the main factors of early oral aging in childhood and their interactions are fundamental for understanding the condition and developing effective control and treatment strategies, particularly given that there is currently no global index encompassing this information. The aim of the present study was the development and determination of content validity of the Childhood Early Oral Aging Syndrome (CEOAS) index for the primary dentition as a diagnostic and epidemiological survey tool. Trial registration: ClinicalTrials.gov ID: NCT06378385.

Hydroxyapatite in oral care products: in vitro effects on erosion/abrasion and analysis of formulation components.

Hydroxyapatite (HAP) is promoted as biomimetic material in dentistry. The aim of the study was to investigate whether HAP-containing formulations can reduce erosive/abrasive tissue loss and to analyse components in these formulations. Two HAP toothpastes with and two without fluoride and a HAP mouthrinse were investigated, controls were active-agent-free toothpaste, SnF2 toothpaste and F/Sn mouthrinse. For 10 d, human enamel samples were eroded for 2 min, 6x/d in 0.5% citric acid and immersed for 2 min, 2x/d in toothpaste slurries or mouthrinse. Half were additionally brushed for 15s, 2x/d. The particulate fraction was extracted and examined morphologically and with element analyses. Other parameters were REA, RDA, fluoride and calcium content. The F/Sn mouthrinse almost completely prevented tissue loss; none of the HAP formulations reduced tissue loss compared to the negative control, two increased it instead. Brushing increased tissue loss in all groups except the F/Sn mouthrinse. All toothpastes contained amorphous particles of different sizes. Elemental analysis identified Si and O, additionally Ca and P were present in small amounts on the particles of the HAP toothpastes and one HAP+F toothpaste. In the liquid phase, elevated calcium levels were found in one HAP toothpaste and in both HAP+F toothpastes; in the formulation with the highest value, the fluoride concentration was low. REA and RDA values were not associated with tissue loss. Whether alone or in combination with fluoride, HAP formulations had either no or a detrimental effect on erosive tissue loss and could not reduce abrasion. In the context of erosive tooth wear, HAP seems to be neither an alternative to fluoride nor a suitable supplement to it.

A Study on Tooth Wear Mechanisms During the Bandsawing of Cr12MoV with a Bimetal Bandsaw Blade

A Study on Tooth Wear Mechanisms During the Bandsawing of Cr12MoV with a Bimetal Bandsaw Blade

Bruxism awareness and self-assessment in dental clinical students: a questionnaire-based study

BackgroundBruxism is a recurrent parafunctional habit characterized by clenching or grinding teeth and/or jaw contractions. It is quite common among dental students and is associated with psychosocial factors such as stress and anxiety. This study aimed to compare bruxism awareness and self-assessment among clinical students with and without bruxism.MethodsThis study included systemically healthy individuals aged 18 to 27 years. Intraoral and extraoral examinations were performed on 128 4th- and 5th-grade dental students with (64) and without bruxism (64), 4th and 5th-grade dental students at Bolu Abant İzzet Baysal University who met the inclusion criteria. The diagnosis of bruxism was based on the 2018 International Consensus and data collected through a validated 33-item questionnaire covering general information and bruxism awareness. The questionnaire included multiple-choice questions on bruxism types, risk factors, symptoms, and impact on periodontal tissues. Statistical analyses were performed via IBM SPSS Statistics, and p < 0.05 was considered statistically significant.ResultsClenching and teeth grinding during sleep, tooth wear, muscle fatigue, pain in the temples, jaw pain, joint trismus, neck pain, and jaw joint pain and clenching while awake were significantly different in bruxism patients (p < 0.05). There was no significant difference between the two groups in terms of bruxism type, symptoms, treatment methods, periodontal tissues, occlusal trauma, diagnostic methods, or the relationship between lifestyle and bruxism (p > 0.05). While 71.9% of those diagnosed with bruxism stated that they had bruxism, 68.8% of those who were not diagnosed stated that they did not have bruxism.ConclusionAlthough dental students are aware of bruxism, their understanding of its multifactorial nature and treatment options needs improvement. Increasing this knowledge could reduce the prevalence of bruxism among dental students and improve patient care.Clinical trial registrationThe clinical trial was retrospectively registered on ClinicalTrials.gov under the identifier NCT06583044, with a registration date of 03/09/2024. https://register.clinicaltrials.gov/prs/beta/studies/S000EUYA00000023/recordSummary.

Recent Advances in Intraoral Scanners.

Intraoral scanners (IOSs) have emerged as a cornerstone technology in digital dentistry. This article examines the recent advancements and multifaceted applications of IOSs, highlighting their benefits in patient care and addressing their current limitations. The IOS market has seen a competitive surge. Modern IOSs, featuring continuous image capture and advanced software for seamless image stitching, have made the scanning process more efficient. Patient comfort with IOS procedures is favorable, mitigating the discomfort associated with conventional impression taking. There has been a shift toward open data interfaces, notably enhancing interoperability. However, the integration of IOSs into large dental institutions is slow, facing challenges such as compatibility with existing health record systems and extensive data storage management. IOSs now extend beyond their use in computer-aided design and manufacturing, with software solutions transforming them into platforms for diagnostics, patient communication, and treatment planning. Several IOSs are equipped with tools for caries detection, employing fluorescence technologies or near-infrared imaging to identify carious lesions. IOSs facilitate quantitative monitoring of tooth wear and soft-tissue dimensions. For precise tooth segmentation in intraoral scans, essential for orthodontic applications, developers are leveraging innovative deep neural network-based approaches. The clinical performance of restorations fabricated based on intraoral scans has proven to be comparable to those obtained using conventional impressions, substantiating the reliability of IOSs in restorative dentistry. In oral and maxillofacial surgery, IOSs enhance airway safety during impression taking and aid in treating conditions such as cleft lip and palate, among other congenital craniofacial disorders, across diverse age groups. While IOSs have improved various aspects of dental care, ongoing enhancements in usability, diagnostic accuracy, and image segmentation are crucial to exploit the potential of this technology in optimizing patient care.

Oral health experience of individuals with eating disorders

BackgroundEvidence on how persons with and in remission from an eating disorder experience their oral health is limited. Dental treatment in Sweden today is often postponed until medical rehabilitation has been completed, but this carries risks. For the patient, the risk is severely impaired oral health and additional suffering, and for both society and the patient, higher costs than might have been necessary.MethodsTen female informants aged 21–51 years (mean age = 36.7, standard deviation 12.7) in remission from an eating disorder with a median duration of 12.5 (range 4–25) years of illness, were questioned in semi-structured interviews about their perceptions of oral health. All participants had been referred to a specialist dental clinic and needed oral rehabilitation. 10% of the patients had been diagnosed with anorexia nervosa and 90% with bulimia nervosa. All had been in remission from the eating disorder for at least one year. Transcripts of the interviews were analyzed with thematic analysis using an inductive approach.ResultsOne overarching theme emerged from the analysis: dental damage persisted as a visible, lingering scar during remission of the eating disorder, reminiscent of the disease and its consequences. The three major themes identified were (1) Physical impact, (2) Psychological impact, and (3) Impact on daily living. The first major theme included erosive tooth wear and impaired oral function and aesthetics. Interviewees described the second as feelings of stigma, guilt, shame, anxiety, and worry, in particular concerning self-inflicted dental damage through self-induced vomiting. The last major theme covered avoidance strategies such as limiting smiling and laughing and minimizing social situations such as eating with others, pursuing a wanted career, and meeting a partner.ConclusionsThe participants in this study expressed a profound negative impact on daily life and a two-fold burden of stigma of having suffered from both an eating disorder and poor oral health.

Proteome of the 2-h in vivo Formed Acquired Enamel Pellicle of Adolescents with Erosive Tooth Wear, Caries, or Sound

Introduction: Acquired pellicle (AP) acts as a membrane preventing acids from coming into direct contact with the tooth. Possibly, individuals with different dental health status present changes in its composition that could disrupt this function. Thus, the aim of this study was to compare the protein composition of the AP in adolescents with erosive tooth wear (ETW), caries, or sound. Methods: Calibrated examiners in BEWE index and ICDAS-merged Epi criteria assessed ETW and caries in a sample of 454 systemically healthy adolescents aged 12–15 years old. Thirty subjects from that sample were selected for this study: ETW group (n = 10; total BEWE ≥9 and absence of dentinal caries lesions); caries group (n = 10; total BEWE <9 and with at least one dentinal caries lesion), and sound group (n = 10; total BEWE <9 and absence of dentinal caries lesions). Two-hour-formation AP samples were taken from buccal, occlusal/incisal, palatal/lingual tooth surfaces. Protein composition was analysed by liquid chromatography-tandem mass spectrometry. Using mean reporter ion values, relative abundances of proteins were compared among the three groups to calculate for fold changes. Twofold protein increases or decreases were reported (t test, p < 0.05). Gene Ontology (GO) of included proteins was assigned. Results: Mean age of participants was 13.1 ± 1.14 years and 56.6% were females. The prevalence of ETW was of 66.6% and of dentinal caries of 33.3%. The GO analyses showed that the majority of detected proteins were stress response related. The ETW group disclosed upregulated relative abundance of antileukoprotease (2.85-fold in ETW vs. sound and 2.34-fold in ETW group vs. caries group); histatin (2.42-fold in ETW group vs. sound group and 2.20-fold in ETW group vs. caries group), and prolactin-induced protein (2.30-fold in ETW group vs. sound group and 2.06-fold in ETW group vs. caries group) (p < 0.05). Hemoglobin subunits alpha (HBA) and beta (HBB) showed decreased relative abundances in the ETW and caries groups when compared to the sound group (HBA: 0.42-fold in ETW group and 0.40-fold in caries group; HBB: 0.45-fold in ETW group and 0.38-fold in caries group; p < 0.05). Conclusion: AP from individuals with ETW showed differences when compared to other dental conditions, with relative abundance increasing of some stress response-associated proteins in ETW and a decrease in proteins related to salivary protection against acid challenges.

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.