A non-carious cervical lesion(NCCL) is the loss of tooth structure at the cementoenamel junction level that is unrelated to dental caries. This study was to evaluate the occlusal and periodontal status of teeth with non-carious cervical lesions. We evaluated 105 teeth with non-carious cervical lesions in 35 subjects aged 38-75 years and characterized them based on the shape and dimension, plaque retention, bleeding on probing(BOP), probing pocket depth(PPD), occlusal status, brushing type, hypersensitivity and wear facet. The results of this study were as follows 1. No significant association was observed between cervical lesions and occlusal contact in lateral excursions. 2. No significant difference occurred in plaque retention, PPD, BOP between teeth with and without cervical lesions. 3. Test teeth had a significantly higher percentage of hypersensitivity and occlusal wear facet than teeth without cervical lesions. 4. Wedge shaped lesions had a significantly higher percentage of plaque than saucer shaped lesions. 5. Teeth with plaque were found to have significantly deeper PPD than teeth without plaque retention in cervical regions. 6. Teeth with occlusal contacts were found to have significantly deeper PPD than teeth without occlusal contacts. 7. No significant association was observed between cervical lesions and PPD independent of plaque retention and occlusal contacts Although more knowledge is necessary, our results suggest that occlusal contact and bacterial plaque may influence on periodontal tissue, but NCCL is not directly associated with periodontal health
Dental Caries ; Hemorrhage ; Hypersensitivity ; Tooth Attrition ; Tooth Cervix ; Tooth*

OBJECTIVES: No evidence has been found on various types of dental erosion, except for occupational dental erosion. This study aimed to evaluate the distribution of four types of dental erosion (occupational, dietary, systemic, and gastric) and its associated factors among workers in factories that use acids. METHODS: Of 89,034 workers from 4,625 factories that use acids, 716 workers from 38 factories were selected for this cross-sectional epidemiological study by using three-stage stratified cluster sampling. Evaluation for dental erosion was performed by a trained dentist by using Kim's criteria, and a saliva sample was collected directly from each participant. Data on acid sources and associated factors were collected by using questionnaires. By using a complex sample analysis, the T test and Rao-Scott chi-square test were applied to analyze the distribution of four acid factors and to evaluate the associated factors. RESULTS: The prevalence of overall dental erosion was 37.7% for occupational dental erosion, 23.1% for dietary dental erosion, 3.1% for systemic dental erosion, and 3.2% for gastric dental erosion. The prevalence of severe dental erosion was 10.5% for occupational dental erosion, 7.1% for dietary dental erosion, 1.8% for systemic dental erosion, and 1.7% for gastric dental erosion. The factors associated with dental erosion were age, sex, acid exposure, dental cervical abrasion, and dental attrition. CONCLUSIONS: Our data showed that the prevalence of dental erosion was high, moderate, and low in occupational, dietary, and gastric and systemic dental erosions, respectively, among workers exposed to acids. The related factors differed according to the types of dental erosion. Our data suggested that different types of promotion programs for dental erosion should be considered according to acid source.
Dentists ; Epidemiologic Studies ; Epidemiology ; Humans ; Prevalence ; Saliva ; Tooth Attrition

PURPOSE: Aims to analyze the occlusal wear patterns in maxillary posterior teeth with palatal side abfractions and study the association between occlusal force and abfractions. MATERIALS AND METHODS: This study was conducted in a total of 308 teeth from 148 patients with palatal side abfractions in maxillary posterior teeth. The occlusal wears in maxillary premolars and molars with palatal side abfractions were classified and recorded. The classification was done by type of teeth, age, and gender, and in order to evaluate the statistical significance between groups, chi-square test was conducted (α = 0.05). RESULTS: Palatal side abfractions in maxillary posterior teeth were observed at the highest frequency in the 1st molars, and in all teeth with palatal side abfractions, more than one occlusal wear was observed. In classification by type of teeth, by age, and by gender, the occlusal wears in teeth with palatal side abfractions were observed at high frequency in cuspal inclined plane, central fossa, and marginal ridge, and there was a statistical significance (P < 0.05). CONCLUSION: Palatal side abfractions were observed at the highest frequency in maxillary 1st molars, and in all maxillary posterior teeth where palatal side abfractions were found, the occlusal wears were observed. And the occlusal wears were observed at high frequency in cuspal inclined plane, central fossa and marginal ridge. Such results show that abfraction is associated with occlusal force.
Bicuspid ; Bite Force ; Classification ; Humans ; Molar ; Tooth Attrition ; Tooth Fractures ; Tooth

The Mental foramen is the exit of the mandibular canal through which the mental nerve pass. The location of the mental foramen, an anthropologically valuable structure, is not only influenced by factors such as tooth attrition, age, loss of teeth, and alveolar bone resorption but also race, diet and geographical position. This study was undertaken to clarify the anthropological characteristics of the location of the mental foramina in the mandibles of the selected Korean population. Forty four mandibles (23 males and 21 females with average age of 66.5 years obtained from the collection of the department of anatomy and cell biology of Hanyang medical college were studied. The apparent position of mental foramen in relation to the mandibular teeth and the true position of mental foramen in relation to the body of the mandible were measured. The obtained results were as follows: In 89% of 35 mandibular sides the mental foramen was located around the second premolar, the most commonly between the second premolar and the first molar, which belongs to type V according to Wang et al. (1986). The distances from the alveolar bone crest across the mental foramen to the lower border of the mandible was 27.4+/-2.4 mm. The mean distances from mental foramen to the alveolar crest and lower border were 12.1+/-2.3 and 13.1+/-2.0 mm, respectively. The mean position of mental foramen was 4.08 on the line between the second premolar and the first molar. The mental foramen of selected Korean population was located more posterioly when compared with many previous reports from various races. The results of this study would be useful to clarify the anthropological position of the mental foramen in Korean.
Anthropology ; Bicuspid ; Bone Resorption ; Continental Population Groups ; Diet ; Female ; Humans ; Male ; Mandible ; Molar ; Tooth ; Tooth Attrition

Overlay complete dentures are simple, reversible and economical treatment modality for patients with congenital or acquired disorders that severely affect the tooth development. It satisfies both the esthetic and functional demands where the extraction of teeth is not generally indicated. In pediatric patients, the overlay dentures establish a relatively stable occlusion that improves patient's tolerance to the future treatment procedures for worn dentition. This clinical report highlights the imperative need of appropriate treatment strategy and application of maxillary and mandibular overlay dentures in a pediatric patient who suffered from congenitally mutilated and worn dentition.
Dentition ; Denture, Complete ; Denture, Overlay ; Humans ; Prosthodontics ; Tooth ; Tooth Attrition ; Vertical Dimension

PURPOSE: The purpose of this study was to compare and analyze the wear of a prosthesis for 6 months after restoration with implant-supported fixed dental prosthesis made of either zirconia or gold. MATERIALS AND METHODS: This study was conducted on patients requiring implant-supported fixed dental prostheses on first or second molar from January, 2015 to January, 2016. A total of 47 prostheses and antagonists were examined. Occlusal surface was recorded by impression of each prosthesis and antagonist 1 week and 6 months after prosthesis delivery. The digital files were created by impression scan. Occlusal shapes of 1 week and 6 months were compared and wear of prostheses and antagonists was analyzed. The Mann-Whitney test was used to analyzed the result data underwent normality test using SPSS (Version 23.0, IBM Corporation) RESULTS: Mann-Whitney test revealed that there was no statistically significant difference in the median amount of mean vertical wear for 6 months in zirconia (50.84 μm) and gold (42.84 μm) prostheses (P > 0.05). When the opposing teeth were natural, the median amount of mean vertical wear of zirconia and gold prostheses was 47.72 μm and 41.97 μm, respectively, and the median amount of mean vertical wear of enamel was 47.26 μm and 44.59 μm, respectively. Statistical analysis showed no significant difference (P > 0.05). CONCLUSION: Despite the short study period and the small number of experimental groups, zirconia and gold showed no significant difference in wear during the first 6 months. Opposing natural enamel also showed no significant difference in the wear.
Clinical Study ; Dental Enamel ; Dental Prosthesis ; Humans ; Molar ; Prostheses and Implants ; Tooth ; Tooth Attrition

Multiple tooth loss and excessive occlusal wear can result in damage to occlusal disharmony, functional disorders and esthetic problems, requiring comprehensive prosthetic treatments. Changing vertical dimension harmonized with surrounding muscle tissue is important. In this case, the patient with loss of vertical dimension caused by severe tooth loss and tooth wear was treated with the analysis of vertical dimension, such as diagnostic model, radiography and various clinical exams. the patient was satisfied with favorable functions and esthetics for 1 years of follow-up.
Esthetics ; Follow-Up Studies ; Humans ; Mouth Rehabilitation* ; Mouth* ; Radiography ; Tooth Attrition ; Tooth Loss* ; Tooth Wear* ; Tooth* ; Vertical Dimension*

BACKGROUND: Though implant dentistry is very successful and predictable in treatment of patients with destroyed dentition, there are some cases with limitations to implant therapy. In these cases, alternative treatment modality should be considered. CASE DESCRIPTION: A patient with destroyed dentition was rehabilitated with a lateral rotational path removable partial denture. According to the diagnosis, we determined to raise vertical dimension for esthetic and functional restoration. The final restoration was performed after four months of provisional period. CLINICAL IMPLICATION: The edentulous patients with compromised esthetics and functions can be successfully treated with a rotational path removable partial denture through adequate treatment planning and precise laboratory procedure.
Dentistry ; Dentition ; Denture, Partial, Removable ; Esthetics ; Humans ; Mouth ; Mouth Rehabilitation ; Tooth Attrition ; Vertical Dimension

OBJECTIVETo investigate the effects of occlusal rehabilitation on chewing patterns of patients with extensive tooth wear.

METHODS29 patients with severe tooth wear were selected and divided into two groups: Group I with complete posterior tooth support (15 cases) and group II with one-side or both side posterior support lost (14 cases). 15 normal old persons were also selected as control group. The surface electromyography (EMG) of masseter(MM), anterior temporalis (TA) and posterior temporalis (TP) during chewing movement were recorded in the stage of pre-treatment, 1 month after temporary restoration and 1 month after permanent restoration. The EMG activity, total cycle duration (TCD) and ratio of activation period to relaxation period (AP/RP) of chewing cycles were measured and compared.

RESULTS1) Before treatment, the TCD of these two groups were longer than normal group, but the differences were not significant (P > 0.05). All of the AP/RPs of MM, TA and TP in group II were significantly higher than that of normal group (P < 0.01), and EMG activity of TA of group II was group I were both significantly lower than that in pre-treatment stage. 3)After permanent restoration, the TCD of group I were significantly lower than that in temporary restoration stage (P < 0.01). In group II, the TCD was continuously slightly shortened, while the AP/RP were significantly lower (P < 0.01) and EMG activities were significantly higher(P < 0.01) than that in the temporary restoration stage.

CONCLUSIONOcclusal rehabilitation could obviously change the chewing patterns and the EMG activities of patients with severe tooth wear.

OBJECTIVETo compare the wear between the enamel and two types of dental decoration porcelains for all-ceramic restorations (Vita-alpha, Vintage AL).

METHODSFriction coefficients, wear scar width, element concentrations and wear surface evolution were considered relatively to the tribology of that in vivo situation. The wear scars of the samples were characterized by means of dynamic atomic force microscopy (DFM). The different element concentrations of the surface before/after the wear test were determined with energy dispersion spectrometry (EDS).

RESULTSThe friction coefficient varied from time in each kind of material. The statistical differences between materials were observed in wear scar width and properties of materials (P<0.05). DFM results showed wear surface of natural tooth full of abrasive particles and denaturation of dental texture. Wear surface of veneering ceramics consisted mainly of abrasive particles, plough and microcracking. EDS results showed that the element concentration of Fe was obviously found on the samples after wear.

CONCLUSIONThe main underlying mechanisms of natural teeth wear are abrasive, and denaturation of dental texture. Abrasive wear, adhesion and fatigue of veneering ceramics characterize the wear patterns which plays different role in Vita-alpha and Vintage AL. The wear patterns of veneering ceramics can be described as mild wear.