Comparison between students' self-assessment, and visual and digital assessment techniques in dental anatomy wax-up grading.

INTRODUCTION: Digital technology has the potential to provide a bias-free evaluation instrument for practical examination grading. E4D Compare software was designed for teaching institutions to allow comparison between scanned models prepared by students and master models prepared by instructors. The aim of this study was to determine the tolerance value for the E4D compare software (E4D Technologies LLC, Richardson, TX, USA) that provides scores comparable with faculty grades for wax-ups #23 and #19. Additionally, this study sought to assess the correlation between students' self-assessments, visual and digital grades and the reliability of the software. METHODS: Student wax-ups (n = 112) were uploaded into the software and then compared with faculty-generated master wax-ups. Digital grading was performed at tolerances 200-800 µm in 50 µm increments and was repeated twice. RESULTS: A tolerance of 350 µm was the closest to faculty grades for #23 and 500 µm was the closest for #19. Visual and digital grades showed moderate to high correlation for both wax-ups. Correlations between students' self-assessments and visual and digital grades improved with #19 versus #23. A near-perfect correlation was found between grades at the first and second digital grading sessions. CONCLUSIONS: The tolerance that closely matches faculty grades differs according to the tooth type. The software provided consistent grades and correlated well with faculty grades. Students' self-assessment skills improved as they proceeded throughout the course. Further studies are necessary to ascertain the role of the software in improving students' self-assessment skills.

Teaching dental anatomy & morphology: An updated clinical- & digital-based learning module.

INTRODUCTION: Dental Anatomy and morphology learning is an essential component of the dental curriculum; students introduced to dental morphology in a detailed textbook style lecture format often have difficulty transferring that knowledge to the associated clinically related activities. The purpose of this article is to describe the rationale, components and advantages of an updated dental anatomy module and present a comparison of student course evaluations for those who received the updated module (CDM) versus those who received the traditional module (TM). METHOD: An updated module was implemented at the University of Kentucky College of Dentistry (UKCD). The updated module consisted of clinically based lectures and incorporated digital technologies in both lecture and laboratory portions of the course as well as a patient-based aesthetic wax-up exercise. The goal of the updated module is to shift emphasis away from decontextualised technical learning towards more active and clinically applicable learning that improves classroom interaction and takes advantage of the current technologies available. RESULTS: The results were statistically analysed using a two-sample t test. The updated module was statistically significantly highly rated by students. CONCLUSION: The updated module was highly appreciated and rated by students. An update to the educational method of teaching dental anatomy and morphology is proposed, clinical dental anatomy teaching results in enhanced students' engagement and assessment. More research and proper strategic planning for implementation of digital technology into the dental anatomy curriculum are needed to adequately utilise these resources.

Detecting demineralization of enamel and cementum after gamma irradiation using radiographic densitometry.

The purpose of this study was to evaluate the ability of radiographic densitometry in detecting the early demineralization of human enamel and cementum in irradiated and non-irradiated teeth. Sixty extracted teeth were divided into two groups: irradiated group and non-irradiated group. After irradiation, the groups were subjected to demineralization-remineralization (PH) cycling. Radiographic densitometric measurements (gray values) of a selected area of interest in the enamel and in the cementum of each tooth were performed at baseline and after PH cycling. After PH cycling, there was a significant reduction in gray values for both groups. The difference between "baseline" and "after PH cycling" values represents the reduction in the mineral content of the hard tissue, i.e., the demineralization. Results show that the demineralization of irradiated tooth enamel and cementum was significantly higher compared to that of non-irradiated tissues as determined by gray-level values. It is concluded that densitometric measurements by means of digital radiographs allow for the detection of demineralization of enamel and cementum, and can be used successfully for diagnosis of the early carious lesions in patients who received head and neck radiotherapy. This will allow implementation of remineralizing therapy and avoid the risk of progression of radiation caries. Furthermore, it is concluded that gamma irradiation with typical therapeutic doses for head and neck carcinoma is a direct cause of demineralization of tooth enamel and cementum.

Non-carious cervical lesions imaged by focus variation microscopy.

OBJECTIVE: The aim of this study is to characterize the morphological and histological features of NCCLs in a group of extracted teeth using a focus variation optical microscopic technique that is capable of detecting minute variation in surface topography. METHODS: Twenty three extracted teeth containing NCCLs were collected. Histological features of the surface and longitudinal cross sections were examined using a focus variation microscope (FVM). RESULTS: The sample included 8 teeth with wedge-shaped lesions; the remaining 15 contained saucer-shaped lesions. Wedge-shaped lesions showed obliterated dentinal tubules, parallel furrows and micro-fractures in the surface; longitudinal cross sections revealed subsurface micro-fractures extending toward the pulp chamber. The surfaces of typical saucer-shaped lesions were smooth and relatively featureless. CONCLUSIONS: FVM imaging shows microstructures that are consistent with simultaneous erosion and toothbrush abrasion. Saucer shaped lesions have a smooth featureless surface as well as craters and dimples that could be attributed to uneven acid attack. In wedge-shaped lesions, the presence of scratches and furrows could be attributed to mechanical forces such as tooth brush abrasion. The furrows and in-surface micro-factures of wedge shaped lesions suggest a possible role of tensile stresses but require further investigation. CLINICAL SIGNIFICANCE: NCCLs present in two morphologies, either saucer-shaped or wedge-shaped. Erosion and toothbrush abrasion are important in both types of lesions. Tensile stresses due to occlusal loading may be important in some wedge-shaped lesions. Knowing the etiology of cervical lesions is the key for their prevention.

The role of fluoride and chlorhexidine in preserving hardness and mineralization of enamel and cementum after gamma irradiation.

The purpose of this study was to evaluate the effect of 0.05% sodium fluoride and 0.12% chlorhexidine mouthwashes on the micro-hardness of tooth enamel and cementum that was exposed to therapeutic doses of gamma radiation. Sixty extracted human teeth were divided into two groups, one was irradiated, the other was not irradiated. The two groups were further subdivided into three subgroups, which were each treated either with 0.05% sodium fluoride or with 0.12% chlorhexidine; the third subgroup served as a control. After demineralization-remineralization cycling, teeth from the irradiated groups showed a significantly lower micro-hardness when compared to those from the non-irradiated groups. Both in the irradiated and non-irradiated groups, teeth from the control subgroups showed a significantly lower micro-hardness, as compared to teeth treated with sodium fluoride and chlorhexidine. For non-irradiated enamel samples, those treated with chlorhexidine showed a significantly less micro-hardness compared to those treated with sodium fluoride. In contrast, irradiated enamel showed no significant difference in micro-hardness, whatever treatment (chlorhexidine or sodium fluoride) was applied. For cementum, treatment with chlorhexidine resulted in a significantly lower micro-hardness compared to sodium fluoride, both for the irradiated and non-irradiated groups. It is concluded that gamma irradiation with therapeutic doses typically used for head and neck carcinoma treatment has a direct effect in reducing micro-hardness of tooth enamel and cementum. Mouthwash protocols including, for example, application of 0.05% sodium fluoride or 0.12% chlorhexidine three times per day for 6 weeks, can protect enamel and cementum against the reduction in hardness and demineralization caused by gamma irradiation. Sodium fluoride offers more protection compared to chlorhexidine.