The use of objective structured clinical examination in dental education- a narrative review.

The Objective Structured Clinical Examination (OSCE) is a performance-based assessment intended to assess medical students' clinical competency in a simulated, standardized environment. Because it measures the student's ability to use clinical knowledge, diagnostic skill, and decision-making, the OSCE is thought to be more objective than traditional tests. OSCE exams have been increasingly employed in dentistry schools, particularly in the last decade, and it is crucial to investigate instructors' and dental students' experiences with this evaluation approach.

Failure loads of heat-pressed versus milled lithium disilicate endocrowns.

OBJECTIVES: This study aimed to compare the failure load of heat-pressed versus milled lithium disilicate endocrowns. MATERIALS AND METHODS: Twenty extracted mandibular molars were sectioned 1.5 mm above the CEJ. Root canal treatment and endocrown preparation were done for all teeth. Samples were then divided into two groups: heat-pressed glass ceramic endocrowns (HP group) (n = 10) and milled endocrowns (CAD group) (n = 10). Cementation was done using self-adhesive resin cement, and a compressive load was applied on the occlusal surface of the specimens until failure occurred. RESULTS: The mean failure loads were significantly higher in the HP group (2546.5 ± 339 N) compared to the CAD group (1759.9 ± 114.2) (p < 0.05), and majority of failures were due to fracture of the restoration. CONCLUSIONS: Failure loads of heat-pressed lithium disilicate endocrown are superior to milled endocrown. CLINICAL RELEVANCE: Molars restored with lithium disilicate endocrowns have higher failure loads than the maximum human bite force regardless of the fabrication method. Although heat-pressed endocrowns have superior failure loads to milled ones, both are indicated for restoring endodontically treated molar teeth.

Marginal and internal fit of lithium disilicate endocrowns fabricated using conventional, digital, and combination techniques.

OBJECTIVE: To compare the marginal and internal adaptation of endocrowns produced using conventional technique, digital technique, and combination (cast digitization) techniques using microcomputed tomography (micro-CT). MATERIALS AND METHODS: Ten freshly extracted human mandibular molar teeth were prepared for all-ceramic endocrowns. A total of 40 Lithium Disilicate (IPS e.max) endocrowns were fabricated and grouped according to the impression and production technique to four groups: Group (CO): Conventional impression/heat pressed endocrowns (n = 10), Group (CAD): Direct scanning of teeth/CAD-CAM endocrowns (n = 10), Group (COMIO): Combination; Cast digitization using Intraoral scanner/CAD-CAM endocrowns (n = 10), Group (COML): Combination; Cast digitization using laboratory scanner/CAD-CAM endocrowns (n = 10). Micro-computed tomography was used to measure the marginal and internal gaps in 11 predetermined sites. Mean marginal and internal gaps were compared using analysis of variance and Scheffe's post hoc test. RESULTS: CO, CAD, COMIO, and COML groups showed significant differences in the mean marginal gap (150 ± 35 µm, 120 ± 27 µm, 110 ± 24 µm, 120 ± 29 µm, respectively p = 0.013), gap at line angle (280 ± 70 µm, 130 ± 37 µm, 140 ± 54 µm, 130 ± 33 µm, respectively, p < 0.001), gap at cavity wall (210 ± 76 µm, 140 ± 43 µm, 140 ± 52 µm, 150 ± 44 µm, respectively, p = 0.010) and gap at pulpal floor (500 ± 150 µm, 240 ± 58 µm, 260 ± 59 µm, 240 ± 64 µm, respectively, p < 0.001). CONCLUSION: Digitally fabricated endocrowns showed superior marginal and internal fit compared to the conventionally fabricated endocrowns. CLINICAL SIGNIFICANCE: Marginal and internal adaptation are detrimental factors for the success and survival of dental restorations including endocrowns. When compared with the conventional impressions and conventional production techniques, Digital workflow is more predictable and reliable as it reduces errors and improves the accuracy of fit.

Effect of the interproximal contact level on the perception of smile esthetics.

BACKGROUND: Many dental and facial components affect smile esthetics, and dental professionals' opinions regarding dental esthetics may not always coincide with the perceptions and expectations of the patients. OBJECTIVES: This work is designed to determine the dimensions of the interproximal contact areas that are considered the most or least attractive according to a group of laypersons, dentists and technicians. MATERIAL AND METHODS: Two photographs of female and male smiles showing a full smile were taken with a Nikon® camera and digitally altered using Adobe® Photoshop. The length of the interproximal contact areas was altered to generate 2 sets of images (3 images of the female and 3 images of the male smile in each set). A group of 40 laypersons, 40 dentists and 40 dental technicians were asked to select the most and the least attractive image in each set. RESULTS: An interproximal contact ratio of 50:40:30 [%] was the most attractive arrangement (40.00% and 38.33% for the female and male smiles, respectively). The 'reversed' ratio of 30:40:50 [%] was the least attractive to the participants (57.50% and 44.17% for the female and male smiles, respectively). There were differences in the rankings of the most and the least attractive smiles among the 3 groups of evaluators. CONCLUSIONS: The 'ideal' interproximal contact ratio of 50:40:30 [%] is perceived to be the most attractive. However, the smile esthetics perception among dental professionals is not always in agreement with the perception of laypersons.

Stress analysis of endodontically treated teeth restored with post-retained crowns: A finite element analysis study.

BACKGROUND: The authors conducted a study to analyze the stress concentration areas in a tooth restored with a post-retained crown under various conditions. MATERIALS AND METHODS: The authors constructed a three-dimensional finite element model describing a maxillary second premolar restored with an all-ceramic crown supported by a titanium post and a resin-based composite core. They applied static vertical and horizontal loads of 100 newton to the cusp tip of the crown and recorded Von Mises and tensile stress values. The variables investigated were the presence of the post, coronal and apical post extensions, post diameter, post shape, and post and core material. RESULTS: The study results showed that horizontal loading generated higher levels of stress than did vertical loading. The greatest stress levels were concentrated at the cervical region and at the post-dentin interface in all models. Under both loads, a higher modulus of elasticity of the post material and a wider post diameter were associated with increased stress values at the post-dentin interface. Reduction of the post extension above the level of bone was associated with increased dentinal stresses near the apex of the post. CONCLUSIONS: Although endodontic posts provide retention for coronal restorations, they result in dentinal stress values higher than those of crowns without posts. Posts that had a similar modulus of elasticity to dentin and smaller diameters were associated with better stress distribution. Resting coronal restorations on sound dental tissues affected stress distribution more than did the core material or the length of the coronal post extension. CLINICAL IMPLICATIONS: Many factors influence the distribution of stress within dentin and, consequently, the fracture resistance of teeth restored with post-retained crowns. Clinicians need to keep these factors in mind when performing endodontic procedures that involve placement of post-retained crowns to ensure optimal success.

Fracture resistance of teeth restored with post-retained restorations: an overview.

INTRODUCTION: Posts have been used efficiently to retain restorations for badly destructed teeth. This article critically analyzes the concerned topics related to the fracture resistance of teeth restored with dowel-retained restorations. METHODS: A systematic review of PubMed/MEDLINE, Cochrane, and Scopus databases was completed (from 1960 to 2010). Single or combined key words were used to obtain the most possible comprehensive list of articles. Checking the references of the relevant obtained sources completed the review along with a manual search to locate related articles on the topic. In vivo and ex vivo (laboratory, computer-based finite element, and photoelastic stress analysis studies) investigations related to the topic were included. RESULTS: Many factors have been proposed to influence the fracture resistance of post-restored teeth. Recognizing the significance of these factors on the fracture resistance of teeth would aid in choosing the suitable treatment modality for every individual case. Fracture resistance was improved if tooth structure loss was limited, a ferrule was obtained, a post with similar physical properties to natural dentine was used, and adhesive techniques for post luting and coronal restoration were used. Adhesively luted resin/fiber posts with composite cores appear to be the best currently available option in terms of tooth fracture and biomechanical behaviour. CONCLUSIONS: Most guidelines were based mainly on ex vivo studies and to a lesser extent on limited in vivo studies. The lack of long-term controlled randomized clinical studies was the main hindrance to reaching a conclusive and undisputable opinion regarding endodontic posts in terms of tooth fracture and biomechanical behaviour.