Functional occlusal patterns during lateral excursions in young adults.

STATEMENT OF PROBLEM: A valid system for assessing and classifying functional occlusion has not been established. The prevalence of anterior protected articulation is not known. PURPOSE: The purpose of this study was to quantify the prevalence of various functional occlusal contact patterns, including anterior protected articulation, among dental students. MATERIAL AND METHODS: Occlusal contacts were examined during lateral excursions from the maximal intercuspal position to the canine-to-canine position in 100 young adults. A combination of 3 common clinical methods was used: a visual examination, articulating paper, and feedback from the participants. RESULTS: Data from 3 classification systems were analyzed: (1) Occlusal contacts on the working side only ­ canine protected articulation was present in 25% of laterotrusions; anterior protected articulation was present in 18.5% of laterotrusions. Group function was present in 56% of laterotrusions. Other schemes were present in 0.5% of laterotrusions. (2) Contacts on both the working and the nonworking side. (3) Contacts on the working and nonworking side during both right and left laterotrusion. Nonworking side contacts were present in 33% of the participants. Nonworking side interference was present in 1 participant. CONCLUSIONS: The prevalence of anterior protected articulation found in this study was high enough to allow anterior protected articulation to be considered one of the fundamental working side occlusal contact patterns. More studies will be necessary to confirm this finding.

A Profilometry-Based Dentifrice Abrasion Method for V8 Brushing Machines Part II: Comparison of RDA-PE and Radiotracer RDA Measures.

OBJECTIVE: The purpose of this study was to compare the abrasivity of commercial dentifrices by two techniques: the conventional gold standard radiotracer-based Radioactive Dentin Abrasivity (RDA) method; and a newly validated technique based on V8 brushing that included a profilometry-based evaluation of dentin wear. This profilometry-based method is referred to as RDA-Profilometry Equivalent, or RDA-PE. METHODS: A total of 36 dentifrices were sourced from four global dentifrice markets (Asia Pacific [including China], Europe, Latin America, and North America) and tested blindly using both the standard radiotracer (RDA) method and the new profilometry method (RDA-PE), taking care to follow specific details related to specimen preparation and treatment. RESULTS: Commercial dentifrices tested exhibited a wide range of abrasivity, with virtually all falling well under the industry accepted upper limit of 250; that is, 2.5 times the level of abrasion measured using an ISO 11609 abrasivity reference calcium pyrophosphate as the reference control. RDA and RDA-PE comparisons were linear across the entire range of abrasivity (r2 = 0.7102) and both measures exhibited similar reproducibility with replicate assessments. RDA-PE assessments were not just linearly correlated, but were also proportional to conventional RDA measures. CONCLUSION: The linearity and proportionality of the results of the current study support that both methods (RDA or RDA-PE) provide similar results and justify a rationale for making the upper abrasivity limit of 250 apply to both RDA and RDA-PE.

A survey of management strategies for noncarious cervical lesions.

Both causation and management of noncarious cervical lesions (NCCLs) (abfractions, wedge-shaped defects, stress-induced cervical lesions, and cervical erosion) remain debatable. A survey of clinicians' perceptions was therefore conducted at a recent professional meeting to determine optimal approaches to NCCL management. Examples of lesions differing in depth (1, 2, and 3 mm) were presented as being either sensitive or nonsensitive, and participants recorded their responses to the presented individual scenarios. This report provides information regarding correlations between increases in lesion depth, lesion sensitivity, and professionals' willingness to restore them. It was also noted that decisions to ensure mechanical retention positively influenced estimates for restoration longevity.

Validation of the Basic Erosive Wear Examination.

The Basic Erosive Wear Examination (BEWE) is a practical index for screening tooth wear, using a 4-point ordinal scale (0-3). The highest score is recorded in each sextant and a total score (or BEWE sextant cumulative) is calculated per subject. This study aims to investigate if the BEWE sextant cumulative score compares to one comprising a percentage score from all tooth surfaces and as a highest BEWE per subject. The aim is to assess the validity of this score. A total of 350 subjects were recruited from hospital and general practice in south-east England. Buccal, occlusal and lingual/palatal BEWE scores were collected and percentages calculated based on scores 1, 1 and above, 2 and above and 3. BEWE sextant cumulative scores and highest BEWE scores were also recorded per subject. Spearman's correlation coefficients (p values) assessed the relationship between BEWE sextant cumulative scores, BEWE percentages and BEWE highest score per subject. The BEWE sextant cumulative score correlates significantly to a BEWE score taken as a percentage score from all tooth surfaces (Spearman's r > 0.5, p < 0.001) and especially to BEWE surface scores of 1 and above and 2 and above (r > 0.8, p < 0.001) and as a highest surface score per subject (r > 0.8, p < 0.001). BEWE sextant score provides a representation of tooth wear on all tooth surfaces. This study validates a tooth wear index, which provides clinicians with risk indicators of a patient's level of tooth wear and may help to guide clinical management.

Long-term effects of tongue piercing--a case control study.

The aim of this study was to evaluate tooth and periodontal damage in subjects wearing a tongue piercing (TP) in comparison to matched control subjects without tongue piercing. Members of the German Federal Armed Forces who had TP (group TP) and a matched control group (group C) volunteered to take part in the study. The time in situ, localization and material of TP were documented. Dental examinations included DMF-T, oral hygiene, enamel fissures (EF), enamel cracks (EC) and recessions. Statistical analysis was determined by χ (2) test and the t test. Both groups had 46 male subjects (mean age 22.1 years). The piercings had been in situ for 3.8 ± 3.1 years. Subjects in the TP group had a total of 1,260 teeth. Twenty-nine subjects had 115 teeth (9.1%) with EF (67% lingual). In group C (1,243 teeth), 30 subjects had 60 teeth with EF (4.8%, 78% vestibular) (p < 0.01). Thirty-eight subjects belonging to group TP had EC in 186 teeth (15%). In group C, 26 subjects with 56 teeth (4.5%) were affected by EC (p < 0.001). Twenty-seven subjects in group TP had 97 teeth (7.7%) with recessions. Lingual surfaces of anterior teeth in the lower jaw were affected most frequently (74%). In group C, 8 subjects had 19 teeth (1.5%) with recessions (65% vestibular). Differences between the two groups were statistically significant (p < 0.001). Tongue piercing is correlated with an increased occurrence of enamel fissures, enamel cracks and lingual recessions. Patients need better information on the potential complications associated with tongue piercing.

The problem with an epidemiological index for dental erosion.

This article reviews and discusses the difficulties posed by the application of epidemiological indices for the measurement of dental erosion. It covers several aspects of index design.

A comprehensive and conservative approach for the restoration of abrasion and erosion. part II: clinical procedures and case report.

This article proposes a comprehensive and conservative approach to the treatment of tooth wear, based on the application of minimally invasive composite restorations to treat both anterior and posterior decay. Three treatment options were considered, in relation to the severity of tissue loss and size of existing posterior restorations. Posterior tooth status actually will guide the clinician toward the most appropriate restorative option. In the presence of limited tissue loss and small fillings, only direct restorations are considered. With moderate tissue loss and medium size existing restorations, a mix of direct and indirect composite restorations is preferred, and with extensive tissue loss and large restorations, mainly indirect restorations will be chosen. The restoration of anterior guidance and a proper smile line are reestablished using adhesive restorations, including primarily direct composite buildups; in the presence of more severe tissue destruction, loss of facial morphology or discoloration, veneers and possibly crowns can be considered. The driving force behind the concept presented in this article is to intercept tissue destruction and restore proper tooth biomechanics, function, and esthetics using adhesive restorations which do not further invade hard tissues.

[Tooth wear, a proposal for an evaluation system]. / Een beoordelingssysteem voor gebitsslijtage.

The present-day terminology and definitions of tooth wear are not unambiguous. For diagnosing tooth wear, however, it is essential that they are unambiguous. In this article a proposal is presented for a tooth wear evaluation system with simplified definitions. This system consists ofa number of modules and can be used for various aspects of the diagnostic procedure. It can be used for the quantification of tooth wear, both for periodic screening and for the monitoring of tooth wear in individual patients. The scoring of occlusal/incisal tooth wear as well as of non-occlusal/non-incisal tooth wear is possible. The evaluative system is also suitable for determining which type of tooth wear, such as attrition, abrasion and erosion, is most likely to have caused any observed loss of hard tooth tissue.

Occlusion factors influencing the magnitude of sleep bruxism activity.

The biomechanical load during strong bruxism activity reportedly causes many dental/oral problems. However, it is unknown whether the magnitude of muscle activity during sleep is controllable. In this study, the relationship between the magnitude of muscle activity during sleep and types of tooth contacts was examined, including anterior and posterior guidance, in order to clarify how occlusion factors contribute to sleep bruxism (SB). An EMG-2-axis accelerometer system was used for monitoring patterns and activities of SB. Bruxchecker was used to evaluate tooth contacts during SB, and a condylograph was used to measure posterior guidance (sagittal condylar inclination). Results show that grinding rather than clenching or tapping was observed in the high SB group, and there was Incisor-Canine-Premolar-Molar (ICPM) tooth contact during SB grinding movement. The canine occlusal guidance (COG) was flatter in the low SB group than in the moderate SB group. Relative canine occlusal guidance (rCOG), which is the difference between the sagittal condylar inclination (SCI) and COG, was larger in the low SB group than that in the high SB group. These findings suggest that the grinding pattern must be controlled to prevent strong bruxism, and that the muscle activity during bruxism can be reduced by controlling the tooth contact pattern during SB grinding.

Clinical survey of cervical tooth lesions in first-appointment patients.

OBJECTIVE: To investigate the relationship between cervical lesions and patient age, brushing method and bruxism based on a clinical survey of first-appointment patients. METHODS: Two hundred and nine patients (118 male, 91 female) who had unfilled cervical lesions were examined. Information on patient age, teeth with lesions, classification of the lesions, brushing method and bruxism was obtained. The data were analysed statistically. RESULTS: Cervical lesions started to develop in the first premolar teeth in the early twenties and became more prevalent with age. A habit of bruxism was associated with an increase in cervical lesions. Brushing was not directly associated with the development of cervical lesions. CONCLUSION: This study suggests that cervical lesions should be treated at an early stage to prevent further problems.

Non-carious cervical lesions on permanent anterior teeth: a new morphological classification.

BACKGROUND: Various cross-sectional forms of non-carious cervical lesions have been described but no formal morphological classification system has been developed. The aims of this study were to describe the spectrum of common morphological forms of non-carious cervical lesions observed within a large sample of extracted human permanent anterior teeth and to develop a system for classification based on morphological features. METHODS: Over 15,000 extracted permanent anterior teeth were examined macroscopically under illumination at 2x magnification. Well-defined, descriptive categories were formed, based on observable non-carious cervical lesion features and using terminology currently reported in the literature. The lesions were then sorted into these categories. RESULTS: Five hundred and forty-two non-carious cervical lesions were identified on 15 289 teeth extracted in the early to mid 20th century, representing a frequency of 3.5%. The main categories developed were "shallow", "concave", "wedge-shaped", "notched", and "irregular". CONCLUSIONS: The new morphological classification system provides an alternative to presently used systems based on aetiology, and should facilitate future research on non-carious cervical lesions.

Clinical study investigating abrasive effects of three toothpastes and water in an in situ model.

OBJECTIVES: This in situ study compared the abrasive effect of repeated brushings (over 10 days) of a low relative abrasive dentine (RDA) toothpaste with moderate and high relative abrasive dentine (RDA) toothpastes, on human dentine in situ. MATERIALS AND METHODS: The study design was single centre, single blind, randomized, split mouth, two period, four-treatment cross-over, in situ study in 20 healthy subjects. Subjects wore bi-lateral lower buccal appliances each fitted with four dentine sections with treatment applied with a power toothbrush, during each 10 day study period. Samples were measured at baseline, day 5 and day 10 by contact profilometry, and baseline and day 10 with non-contact profilometry. RESULTS: Nineteen subjects were included in the efficacy analysis. Results as measured by contact and non-contact profilometry from brushing with the moderate RDA paste and high RDA paste showed significantly (p<0.0001) more abrasion to dentine than brushing with the low RDA paste or water after 10 days. Dentine loss following tooth brushing with the low RDA paste was not significantly different from brushing with water, after 10 days. CONCLUSIONS: The methodology successfully showed clear differentiation between the amount of dentine lost following toothbrushing with the low RDA paste compared to the moderate or high RDA pastes. Dentine loss following brushing with the low RDA paste showed a comparable degree of abrasion to brushing with water.

Dental arch dimensions and tooth wear in two samples of children in the 1950s and 1990s.

AIM: The objective of this study was to compare the degree of tooth wear in posterior deciduous teeth and the dental arch dimensions in the mixed dentition in two modern samples living in the same geographic area and separated by almost 35 years. METHODS: Dental casts of a group of subjects born between 1953 and 1959 were compared with subjects born between 1990 and 1998. The evaluation of tooth wear scores and measurements for posterior and anterior arch segments, intermolar and intercanine width, and mesiodistal size of incisors were taken. The available anterior space in both arches and the posterior and anterior transverse dimensions were calculated. Groups were compared using a nonparametric test (Mann-Whitney U-test) for independent samples (P<0.05). RESULTS: The results show that both boys and girls of the 1990s showed significantly smaller maxillary intermolar width when compared with the 1950s. Posterior transverse interarch discrepancy was significantly minor in girls of the 1990s. The comparison of abrasion showed significant differences between the two groups for all examined teeth which appeared to be more abraded in the 1950s group. CONCLUSIONS: This association can partially explain the greater risk of developing malocclusions in contemporary children compared with children living 35 years before.

Reliability of an occlusal and nonocclusal tooth wear grading system: clinical use versus dental cast assessment.

The reliability of a newly developed tooth wear grading system was assessed both clinically and on dental casts by two observers using 20 participants. The reliability of clinical occlusal/incisal tooth wear grading was fair-to-good to excellent, while that of most of the clinical nonocclusal/nonincisal grades was at least fair-to-good. Dental cast assessment frequently yielded poor reliabilities, especially for nonocclusal/nonincisal surfaces. Hence, occlusal/incisal wear could be graded more reliably than nonocclusal/nonincisal wear, while the clinical assessment of tooth wear was more reliable than the grading of dental casts.

A new index of tooth wear. Reproducibility and application to a sample of 18- to 30-year-old university students.

A modified wear index, in which the wear of enamel and dentine are recorded separately, is described. The index was applied to estimating the prevalence and extent of tooth wear in a single convenience sample of 18- to 30-year-old students attending a university in London. The subjects were examined under good lighting in a dental chair away from a dental school. A total of 707 females and 303 males were recruited with a mean age of 21.9 years (standard deviation = 0.1, range = 18-30) and examined by 3 trained and calibrated examiners. Intra-examiner intra-class correlation coefficients showed a range of 0.44-0.88. The unweighted kappa scores were above 0.88 for enamel and dentine. The presence of enamel wear was common to all subjects, but 6.1% of the participants had more than one third of the tooth surface affected. Dentine was exposed on 5.3% of all surfaces, with the largest proportion accounting for less than 10% of the tooth surface (grade 1). The proportion of subjects with at least 1 surface with dentine exposed was 76.9% of the total population. The males had significantly more wear in dentine than the females (p = 0.001). The inter-examiner intra-class correlation coefficients for enamel and dentine were 0.87 and 0.92, respectively. The reproducibility of the index was comparable to other analyses and provides an opportunity to assess the prevalence of enamel wear in large population-based studies.

Correlations of noncarious cervical lesions and occlusal factors determined by using pressure-detecting sheet.

OBJECTIVES: The purpose of this clinical study was to examine the relationships of v-shaped noncarious cervical lesion (NCCL) formation with occlusal factors. METHODS: A total of 159 male self-defense force officials with a mean age of 36.2 years participated in this study. All present teeth were examined for the presence and type of NCCL using the Tooth Wear Index (TWI). The subjects were then interviewed about bruxing and toothbrushing habit. Finally, occlusal force, occlusal contact area and average pressure were measured using a pressure-detecting sheet. Subject-level logistic regression was carried out to assess the associations of factors with presence of v-shaped NCCL teeth. Subjects without v-shaped NCCL were designated as control subjects. RESULTS: Totally, 4518 teeth were examined. Seventy-eight subjects (49.1%) had one or more teeth with typical v-shaped NCCL (259 teeth). The number of teeth with v-shaped NCCL of grade 2 (defect less than 1mm in depth) was 195 (4.3%), and the number of teeth with v-shaped NCCL of grade 3 (defect 1-2mm in depth) was 54 (1.2%). The prevalence of teeth with v-shaped NCCL was significantly higher in the maxilla than in the mandible. Most of the NCCL teeth were premolars. There was no significant difference between teeth with NCCL on the right side and those on the left side. Subject-level logistic regression analysis revealed that age (OR=1.11), toothbrushing pressure (400g, OR=2.43) and occlusal contact area (>23.0mm(2), OR=4.15) were associated with the presence of NCCL teeth. CONCLUSIONS: It is concluded that aging, toothbrushing pressure and occlusal contact area are associated with the presence of NCCLs.

Free gingival grafts to increase keratinized tissue: a retrospective long-term evaluation (10 to 25 years) of outcomes.

BACKGROUND: Gingival augmentation procedures are indicated primarily to increase an insufficient amount of gingiva and sometimes to halt the progression of gingival recession. The aim of this retrospective long-term study was to evaluate changes in the amount of keratinized tissue (KT) and in the position of the gingival margin after free gingival graft procedures over a period of 10 to 25 years. METHODS: One hundred three subjects presenting with 224 sites completely lacking attached gingiva associated with gingival recessions were treated in a private practice. The experimental sites were treated with gingival augmentation procedures (free gingival grafts). The grafts were positioned at the presurgical level of the gingival margin or in a submarginal position. Clinical variables, including recession depth, amount of KT, and probing depth (PD), were measured at baseline (T(0)), 1 year after surgery (T(1)), and at the end of the follow-up period (10 to 25 years) (T(2)) and analyzed using descriptive statistics and multilevel models. RESULTS: From T(0) to T(1), the gingival margin shifted coronally 0.8 mm, and KT increased 4.2 mm. From T(1) to T(2), the gingival margin shifted coronally 0.6 mm, and the overall KT decreased 0.7 mm. PD remained stable. CONCLUSION: Gingival augmentation procedures performed in sites with an absence of attached gingiva associated with recessions provide an increased amount of KT associated with recession reduction over a long period of time.