Tooth Wear Evaluation System 2.0-Evaluation of diagnostic reliability in the assessment of signs and symptoms for tooth wear by non-experts.

BACKGROUND: Tooth wear is a multifactorial condition that manifests through various signs and symptoms. These individual signs and symptoms were described in multiple studies, leading to the inclusion in TWES 2.0 (Tooth Wear Evaluation System 2.0) and the forthcoming DC-TW (Diagnostic Criteria for Tooth Wear). However, a study evaluating their reliability has yet to be conducted. OBJECTIVE: The aim of the study was to examine the reliability in the assessment of 6 signs of pathological tooth wear and 18 clinical signs and symptoms determining aetiology, all of which are included in the TWES 2.0/DC-TW. METHODS: 48 dental students (operators) evaluated patient cases from a patient pool of 14 patients on dental casts and high-resolution intraoral photographs. The agreement between all operators for each sign and symptom was calculated based on ICC (Intraclass Correlation Coefficients). Additionally, the agreement of each operator's evaluation with a predefined sample solution was calculated based on Cohen's kappa. RESULTS: Inter-user agreement ranged from near perfect (0.91) to poor (0.02) for the various pathology signs or aetiology symptoms of tooth wear (mean 0.32). The agreements of the operator's ratings compared to the sample solution resulted in Cohen's kappa from 0.18 to 1 (mean 0.59) for the pathology signs and ranged from 0.02 to 0.51 for the aetiology signs (mean 0.38). CONCLUSIONS: The reliability of the signs and symptoms examined and the ability of individual investigators to correctly identify and assign signs and symptoms varied widely. The current assessment tools for the qualification of tooth wear need further refinement, and examiners need intensive training in tooth wear assessment.

Reliability of the Assessment of Tooth Wear Severity on Dental Hard Tissues and Dental Restorations, Using the TWES 2.0, by Nonexperts.

BACKGROUND: Tooth wear is a multifactorial process resulting in the loss of dental hard tissues. For its assessment, the tooth wear evaluation system (TWES) 2.0 has been published. Previous studies on the TWES involved well-trained practitioners, rather than nonexperts. OBJECTIVE: The first aim of this study was to investigate the reliability of the assessment of tooth wear severity on dental hard tissues, using the TWES 2.0, by nonexperts. The second aim was to investigate the reliability of assessment of wear severity on dental restorations, using a third scale. METHODS: Forty-seven dental students evaluated at least 9 of 14 possible patient cases on dental casts and intraoral photographs. Cohen's kappa (agreement with sample solution) and Fleiss' kappa (Inter-rater reliability) were calculated. RESULTS: The agreements of the operators' ratings compared to the sample-solution resulted in Cohen's kappa between 0.02 and 0.9. The agreements were 0.34 for occlusal; 0.43 for vestibular; 0.57 for oral surfaces. Inter-rater reliability (Fleiss' kappa) was 0.35 for occlusal, 0.17 for vestibular and 0.24 for oral assessment. The inter-rater reliability of the ratings on tooth surfaces with restorations was lower with 0.21 (occlusal), 0.14 (vestibular) and 0.39 (oral). The agreement on different restorations differed tremendously. CONCLUSIONS: The ability to correctly assess the cases varied considerably between individual examiners. Within the limits of this study, assessment of restorations was slightly more challenging compared to natural teeth, particularly in occlusal regions or when the restorative material is gold. Subsequent studies should address whether enhanced training and improved definition of tooth wear grades result in higher reliability scores.

Tooth Wear Evaluation System (TWES) 2.0-Reliability of diagnosis with and without computer-assisted evaluation.

BACKGROUND: Tooth wear is a multifactorial process, leading to the loss of dental hard tissues. Therefore, it is important to detect the level of tooth wear at an early stage, so monitoring can be initiated. The Tooth Wear Evaluation System (TWES) enables such a multistage diagnosis of tooth wear. The further developed TWES 2.0 contains a complete taxonomy of tooth wear, but its reliability has not yet been validated. OBJECTIVES: The aim of the study was to examine in a randomised controlled trial (RCT) whether diagnoses made based on the TWES 2.0 are reproducible and whether this reproducibility is also achieved with computer-assisted diagnostics. METHODS: 44 dental students received extensive training in TWES 2.0 assessment and taxonomy. The students each evaluated at least 10 (of the present 14) anonymised patient cases using gypsum models and high-resolution intra-oral photographs according to TWES 2.0. One half initially evaluated on paper; the other half used dedicated software (CMDfact / CMDbrux). After half of the patient cases (5), the evaluation methods were switched (AB/BA crossover design). The diagnoses were then evaluated for agreement with the predefined sample solution. RESULTS: Evaluation of agreement with the sample solution according to Cohen's kappa indicated a value of 0.46 for manual (traditional) evaluation; and 0.44 for computer-assisted evaluation. Evaluation of agreement between examiners was 0.38 for manual and 0.48 for computer-assisted evaluation (Fleiss' kappa). CONCLUSION: The results of this study proved that the taxonomy of the TWES 2.0 has acceptable reliability and can thus be used by dentists. Accordingly, the system can be learned quickly even by untrained practitioners. Comparable results are achieved with computer-assisted evaluation.

Reproduction accuracy of articulator mounting with an arbitrary face-bow vs. average values-a controlled, randomized, blinded patient simulator study.

OBJECTIVES: The benefit from positioning the maxillary casts with the aid of face-bows has been questioned in the past. Therefore, the aim of this study was to investigate the reliability and validity of arbitrary face-bow transfers compared to a process solely based on the orientation by means of average values. For optimized validity, the study was conducted using a controlled, randomized, anonymized, and blinded patient simulator study design. MATERIAL AND METHODS: Thirty-eight undergraduate dental students were randomly divided into two groups; both groups were applied to both methods, in opposite sequences. Investigated methods were the transfer of casts using an arbitrary face-bow in comparison to the transfer using average values based on Bonwill's triangle and the Balkwill angle. The "patient" used in this study was a patient simulator. All casts were transferred to the same individual articulator, and all the transferred casts were made using type IV special hard stone plaster; for the attachment into the articulator, type II plaster was used. A blinded evaluation was performed based on three-dimensional measurements of three reference points. RESULTS: The results are presented three-dimensionally in scatterplots. Statistical analysis indicated a significantly smaller variance (Student's t test, p < 0.05) for the transfer using a face-bow, applicable for all three reference points. CONCLUSIONS: The use of an arbitrary face-bow significantly improves the transfer reliability and hence the validity. CLINICAL RELEVANCE: To simulate the patient situation in an individual articulator correctly, casts should be transferred at least by means of an arbitrary face-bow.

Quality improvement of functional diagnostics in dentistry through computer-aided diagnosis: a randomized controlled trial.

Functional diagnostic examinations such as clinical functional analysis and manual structural analysis ('orthopedic tests') allow the dentist to establish a structured diagnosis. Previously, the process of correlating findings with the appropriate diagnoses was guided by human thought processes alone. The experimental diagnostic randomized controlled trial (RCT) in this study investigated whether computer-aided diagnosis (CADx) of temporomandibular disorders (TMD) offers quality advantages over traditional diagnosis (TRAD). SUBJECTS AND METHODS: Thirty-nine 5th-year dental students (examiners) at a university in Hamburg, Germany, received joint training in the diagnosis of TMD by clinical functional analysis and manual structural analysis ('orthopedic tests'). This study is based on anonymized data from 10 patients who were consecutively recruited at a specialized TMJ treatment center. The examiners were randomly allocated to two groups. Each examiner established a structured diagnosis through a traditional diagnostic method and by computer-aided diagnosis (CMDfact 4 functional diagnostics software) of five cases, each using the AB/BA crossover design. The diagnoses established by each individual examiner were then compared with the corresponding reference diagnoses (gold standard) and with those of the other examiners. RESULTS: Cohen's kappa coefficient analysis showed that median agreement with the reference diagnoses was significantly higher (P < 0.001) with computer assistance (median 0.692) than without it (0.553). Fleiss' kappa showed that the median interexaminer consistency of diagnoses was significantly higher (P < 0.001) with computer assistance (0.497) than with traditional diagnostic methods alone (0.271). Likewise, the number of false-positive and false-negative diagnoses was significantly lower with computer assistance (P < 0.001). CONCLUSIONS: This study determined that dentists who are less experienced and not specialized in dental functional diagnostics achieve a significantly better and more consistent diagnostic quality with computer assistance by means of the system used in this study. Therefore, it seems advisable to extend computer-aided diagnostics to further functional examination techniques (condylar position analysis and jaw motion analysis).

Influence of tongue position on the determination of tooth shade.

STATEMENT OF PROBLEM: Dentists frequently use electronic devices to determine tooth color. However, neither the instructions for these devices nor the accompanying brochures refer to the environmental conditions required at the point of measurement. PURPOSE: The purpose of this multicenter prospective clinical study was to reveal whether a change in the oral background influences tooth color determination. MATERIAL AND METHODS: Students (N=42) at the dental clinic in Berlin, Leipzig, Greifswald and Olomouc (women n=27, men n=15) participated in this study. It was their first contact with the spectral photometer (Easyshade Advance 4.0; VITA Zahnfabrik). After a short introduction on how to use the device, the students made 1-point measurements on the same patient on the maxillary central incisor. In the first measurement, the patient's mouth was open, and the palatal surface uncovered. In the second measurement, the patient's mouth was closed slightly, and the tongue pressed on the lingual surface of the maxillary central incisor. The mean ±SD and the 95% confidence interval (95 % CI) were calculated using the Student t test for each test series (α=.05). RESULTS: Statistical evaluation of the 2 measurements revealed changes in the L*a*b* values with a mean L*=0.204, a*=-0.351, and b*=0.02; a median of 0.4, -0.3, and -0.1, respectively; a ±SD of 2.37, 0.64, and 0.89, respectively; and 95% CIs of L*=-0.476 to 0.884, a*=-0.531 to -0.702, and b*=-0.23 to 0.52, respectively. These differences were not statistically significant (P>.05). The measurements of L*, a*, and b* with and without tongue coverage of the lingual surfaces of the maxillary teeth did not show any statistically significant differences (P=.663). CONCLUSIONS: The results demonstrate that the position of the tongue does not influence measurement accuracy during the application of the Easyshade Advance device.

The Implementation of Elaborative Feedback for Qualitative Improvement of Shade Matching-A Randomized Study.

OBJECTIVES: The objective of this prospective learning research study is to examine the impact of structured elaborative feedback in practical skills teaching of visual and digital shade matching. MATERIALS AND METHODS: A total of 60 preclinical dental students participated in the study. The mean average age was 23 years, of which 37 were female (61.7%) and 23 male (38.3%). The participants were randomly divided into a study and control group (n = 30 each). Recording of shade matching was carried out on the phantom patient using clinically simulated settings with elaborative feedback in the study group (T1). Nine items were recorded for visual shade matching and six items for digital shade-taking. The errors were coded. The lower the total (max. 30 points), the fewer the errors made by students during shade determination. The subject labeled the tooth color using VITA 3D-Master and VITA Easyshade (Vita Zahnfabrik, Bad Säckingen, Germany). RESULTS: On comparing the two groups, the study group and the control group showed a similar mean error value at reference time T1. After intervention (T2) it was possible to achieve a clear improvement in the rate of errors for study group. In the study group there was a significant difference between the ΔE values from time T1 and T2 of visual shade matching (p <0.05). The digital ΔE values show in total no significant changes. CONCLUSION: Elaborative feedback in conjunction with standardized checklists can lead to a substantial improvement among students in terms of visual shade matching. CLINICAL SIGNIFICANCE: Correctly determining the tooth shade is an essential treatment step in esthetic reconstructive dentistry. Color is probably one of the most important determinants of esthetics in dentistry. Factors such as lighting conditions, gender, age, experience, and color vision impairment affect the process of shade matching. With an elaborative feedback in conjunction with standardized checklists can lead to a substantial improvement among students in terms of visual shade matching. (J Esthet Restor Dent 28:277-286, 2016).

Motion analysis of the mandible: guidelines for standardized analysis of computer-assisted recording of condylar movements.

Mandibular movement recording has long been established as the method for the physiological design of indirect dental restorations. Condylar movement recording is the basis for individual, patient-specific programming of partially or fully adjustable articulators. The settings derived from these recordings can generally be used in both traditional mechanical and electronic virtual articulators. For many years, condylar movement recordings have also provided useful information about morphological conditions in the temporomandibular joints (TMJs) of patients with masticatory system dysfunction based on the recorded movement patterns. The latest clinical application for recorded jaw-motion analysis data consists of functional monitoring of the patient as a diagnostic and surveillance tool accompanying treatment. Published parameters for the analysis of such recordings already exist, but a standardized and practicable protocol for the documentation and analysis of such jaw-movement recordings is still lacking. The aim of this article by a multicenter consortium of authors is to provide an appropriate protocol with the documentation criteria needed to meet the requirements for standardized analysis of computer-assisted recording of condylar movements in the future.

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

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

Visual Versus Digital Color Determination of 3D-Printed Teeth as an Exercise in Dental Students' Education.

Visual color determination is part of the daily routine in dental practice. However, it is not a part of dental education so far. The aim of this study was to evaluate whether visual or digital tooth color determination of 3D-printed teeth is a reliable tool for inexperienced dentistry students. Preclinical dental students evaluated eleven 3D-printed, tooth-shaped samples (VarseoSmile Crown plus, BEGO, Bremen, Germany) of different color shades. Visual shade determination using a reference scale (3D-Master Toothguide (3DM_TG), VITA Zahnfabrik, Bad Säckingen, Germany), followed by a digital color determination using a spectrophotometer (VITA Easyshade V, (ES_V), VITA Zahnfabrik), was performed. Color deviation was calculated in the Lab* color space (ΔE00) and converted into CIELAB 2000. The results were evaluated using the Mann-Whitney U test and the Wilcoxon Rank Sum test (α = 0.05). Significant differences between visual and digital color determination were proven (p < 0.001). Visual color determination (3DM_TG) showed a mean deviation (ΔE00 ± 95%CI) of 6.49 ± 0.47. Digital color determination (ES_V) showed significantly lower mean deviations of ΔE00 of 1.44 ± 0.58. Digital tooth color measurement using a spectrophotometer was a more reliable tool for the color determination of 3D-printed teeth for inexperienced dentistry students.