Search

Background: This study aimed to compare the efficacy of three different techniques, namely virtual simulation technology (VS), traditional pathological typodont (TT), and quail egg (QE), in pre-clinical training of periodontal ultrasonic scaling. It also aimed to propose an integrated teaching approach for ultrasonic scaling teaching. Methods: This single-blind randomized multi-arm trial enrolled 108 fourth-year students from Guanghua School of Stomatology at Sun Yat-sen University. The participants were randomly, evenly assigned to VS, TT, or QE group. First, the participants received theoretical review on ultrasonic scaling and demonstrative teaching. Then in the 90-minute operation training by group, students used traditional typodont equipped in head-simulators, raw quail eggs, or scaling module of the UniDental VS system respectively. Then all participants practiced on pathological models for 30 min. In the final operation examination, participants were instructed to remove the supra- and sub-gingival calculi pre-set on designated teeth by ultrasonic scalers within 30 min. Their performances were evaluated by residual calculus rate and a multi-perspective scoring scale. After the examination, questionnaires were provided to assess the teaching effects of each method and the fidelity of VS. Statistical analysis was carried out using one-way, two-way ANOVA, and multiple t-test. Results: Students in VS group had significant higher total test scores than QE group (87.89 ± 6.81, 83.53 ± 8.14) and TT group (85.03 ± 6.81). VS group scored higher in several dimensional comparisons with the other two groups, especially in difficult situations. QE group had higher scores particularly in force application and supra-gingival scaling. TT group scored the highest in pivot stability practice and body position training. Students gave higher scores when assessing the fidelity of VS than experienced teachers. Conclusion: The study highlights the importance of specialized pre-clinical training on ultrasonic scaling for dental students. The methods adopted in current study (VS, TT and QE) each offered unique advantages in education, which can be combined to create an integrative teaching procedure. This procedure aims to provide an effective, advisable and normative pre-clinical training procedure for ultrasonic scaling. By utilizing the strengths of each method, dental educators can deliver high-quality training and ensure that students are well-prepared for clinical practice. [ABSTRACT FROM AUTHOR]

Objectives: Wax typodonts are widely used as pre‐clinical teaching tools to test and research the complex force systems created by archwire activations, however, a limitation is the inability to quantify the resultant statically indeterminate tooth movements. The aim of this study was to develop an analogue‐to‐digital typodont system to quantify the effects of archwire activations on individual typodont teeth in three dimensions. Methods: The typodont system was developed using CAD/CAM technology. Posterior expansion, squared, tapered, asymmetrical arch forms and reversed curve of Spee activations were tested with three repeats. The resulting three‐dimensional movements of individual typodont teeth were assessed with six degrees of freedom (df). Cartesian coordinate systems were set for each tooth. Mesio‐distal, bucco‐lingual and intrusive–extrusive movements were assessed as changes in the location of the geometrically estimated centre of resistance in the x, y and z axes, respectively. Torque, tip and rotation movements were assessed as the rotations around the mesio‐distal, bucco‐lingual and intrusive–extrusive axes, respectively. Results: Individual typodont tooth displacements from each activation could reliably be described with six df. The transversal‐to‐sagittal movement ratio ranged from 2:1 to 7:1, depending on the activation. Asymmetrical arch form activations caused a midline shift and affected the lateral overjet. Reversing the curve of Spee led to intrusion of incisors and second molars, extrusion of premolars and first molars and pronounced first and third order effects. Conclusion: The digital typodont system is a promising teaching tool. The tested activations have implications in three dimensions, which should be considered when planning tooth movements. [ABSTRACT FROM AUTHOR]

Background: Toothbrushes require flexibility to access all dental surfaces and remove plaque effectively, but they should also aim to prevent or limit overbrushing and consequent damage to teeth and gums. In two studies, the physical properties and cleaning performance of specialist test toothbrushes with flexible necks were compared to a reference rigid-necked toothbrush. Methods: In Study 1, a universal testing machine (Instron E 10,000) with a specially designed setup was used to test the deflection behaviour of toothbrush head and neck. Untufted toothbrushes were fixed in a custom holder and force was applied to the head while the deflection was measured. In Study 2, one control and five test toothbrushes were assessed using a robot system to simulate the cleaning of artificial plaque from defined surfaces of artificial replicated human teeth in a model oral cavity (typodonts). Results: Study 1 showed that the flexible-neck toothbrush deflected 2 to 2.5 times more than the rigid-neck reference toothbrush when same force was applied to the toothbrush head. Study 2 revealed that all five test toothbrushes showed statistically superior simulated plaque removal to the reference toothbrush. This superiority was observed for all test toothbrushes employing horizontal and rotating brushing action (all p = 0.001) but only three of the five toothbrushes when vertical brushing was employed (all p = 0.001). Cleaning efficacy of the test toothbrushes was demonstrated both interdentally and at the gumline locations. The Complete Protection toothbrush showed the most effective cleaning performance followed by the Repair and Protect and Rapid Relief toothbrushes. Conclusion: The addition of a flexible-neck component to the toothbrush designs helped to reduce stiffness and may allow more effective cleaning compared to rigid designs with controlled force distribution on the teeth and gums. This may help to provide plaque control at all potential risk areas in an in vitro robot model and could support good oral hygiene in-use. [ABSTRACT FROM AUTHOR]

Objective: Research on evaluation of crowns made by the latest contemporary dental computer-aided design/computer-aided manufacturing (CAD/CAM) systems for their marginal adaptation is scarce. The purpose of this in vitro study was to evaluate the marginal integrity of crowns fabricated by the latest Chairside Economical Restorations of Esthetic Ceramic (CEREC) system using 2 different finish line preparation designs: chamfer and shoulder.Materials and Methods: Typodont teeth were divided equally into 2 groups, A and B. The teeth were prepared for full coverage crowns with a shoulder (group A) and chamfer (group B) finish line design. An experienced prosthodontist prepared all crown preparations. Evaluation of 6 sites per sample was completed by 2 calibrated, experienced prosthodontists using the modified US Public Health Services (USPHS) criteria. The descriptive statistics and Z-test were used to evaluate the results.Results: A total of 180 teeth were included in the study (90 teeth in each group). Only 2 crowns in group A and 1 crown in group B were clinically unacceptable. There was no statistical significance (p = 0.282) between the 2 groups regarding finish line design.Conclusions: The CEREC system provides clinically acceptable crowns and can safely be utilized in dental treatment. Therefore, CAD/CAM restorations could be considered as a safe treatment modality by dental professionals. [ABSTRACT FROM AUTHOR]

Background: All-ceramic crown (ACC) preparations are widely used in day-to-day dental clinical practice. Objectives: This study aimed to evaluate all-ceramic crown preparations performed by pre-clinical dental students at the College of Dentistry, Jazan University in Saudi Arabia and to compare the quality of the preparations between male and female groups. Materials and Methods: A total of 95 ivory teeth were prepared by fourth-year dental students (44 males, 51 females). The students prepared a maxillary right central incisor for ACC after mounting in the Frasaco typodont arches. Two silicone putty indexes for maxillary anterior were obtained that extended to cover one or two teeth on either side. The facial index was used to provide information about the facial reduction mesio-distally. Another index was prepared by cutting the silicone in half along the faciolingual midline of the prepared tooth, providing us with incisal, buccal, palatal, and axial reductions, in addition to biplane reduction. The data were encoded into a Statistical Package for Social Sciences program and analyzed accordingly using Chi-square test. Results: The preparations of ACC for maxillary anterior teeth were acceptable, ranging within 60%-85% in all criteria, which included structural durability, retention, and resistance. The male group was more excellent in incisal reduction (41.0%), whereas the female group was more excellent in axial taper preparations (59.1%), resulting in significant differences between genders in this preparation criteria. All gender groups showed acceptable tooth preparations in shoulder reductions and location of finish lines, ranging within 57%-89%. Conclusion: The preparations for ACC achieved by these dental students were considered clinically acceptable. The students clearly understood the principles of crown preparation. However, they still require more practice in order to master the art of crown preparation. [ABSTRACT FROM AUTHOR]

The use of computers to aid in instruction and help decrease the subjective component of assessment is steadily increasing. One of the potential barriers to the effective utilization of CAD/CAM technology for assessment purposes is the efficient scanning of the teeth being used for comparison. The purpose of this pilot study was to determine if the use of different typodonts, of the same make and model, has any significant effect on the percent comparison results when using E4D Compare. Tooth #30 was prepared by a faculty member to represent what dental students at Georgia Regents University are taught as the ideal preparation for a full gold crown. Ten typodonts of the same make and model were selected for comparison. Three different examples of students’ preparations were scanned and compared to the ideal preparation. Each of the three student preparations was subjected to ten trials (occasions), one for each typodont, at five tolerance levels: 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, and 0.5 mm. The intraclass correlation coefficient (ICC) was used to measure the intrarater agreement among the typodonts at the various tolerance levels. The agreement coefficients (0.971–0.984) indicated very little variability attributable to the use of a different typodont. The high agreement coefficients achieved using different typodonts of the same make and model provide evidence for the interchangeability of typodonts when assessing a student’s performance in the preclinical simulation environment. [ABSTRACT FROM AUTHOR]

In this study, the authors evaluated the accuracy and precision of non-clinical testing for dental students' crown prepara-tion proficiency on a manikin-mounted typodont as a predictor of performance on patients. Eighty-six seniors at Baylor College of Dentistry were evaluated by three calibrated senior faculty members from the general dentistry department. Four areas of interest were evaluated: occlusal reduction; axial reduction; margins, design, and finish line; and operative environment. Stan-dardized grading scales were utilized to evaluate these preparation components. The kappa agreement statistic was used to assess agreement for the areas, which were then compiled to get an overall performance score. A Bland-Altman plot was generated and analyzed for agreement on overall performance between typodont and patient. Results of the analyses showed weak agreement between the two measurements for all four areas of interest with large variation in the differences. When the pairs of overall performance scores were compared, the Bland-Altman plot indicated that the typodont composite score was often larger than the patient composite score, especially for poorer performing students. The authors conclude that students' clinical performance on typodonts is a poor predictor of their clinical performance on patients since the students performed much worse on the clinical crown examination than on the typodont examination. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Orofacial Orthopedics/Fortschritte der Kieferorthopadie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective: To determine the magnitude and reproducibility of forces generated by clinicians during laceback placement using a force-measuring typodont. Setting: An in vitro investigation. Materials and methods: An in vitro typodont model was developed, which incorporated strain gauges attached to a personal computer to allow measurement of the force generated on application of lacebacks. Ten operators were instructed to place lacebacks five times, on two separate occasions (T1 and T2). Inter-operator and intra-operator forces produced at T1 and T2 were compared. Main outcome measures: Forces generated by laceback placement. Results: The forces generated by clinicians ranged from 0 to 11.1 N. There were significant differences in the mean forces generated by the different operators (P<0.001), with differences between time points not being consistent across all operators (P<0.001). Some operators were more consistent than others in the forces generated. Conclusion: In vitro, there was a large inter-operator variation in the forces produced during laceback placement. With the in vitro model used in this study, few operators applied similar forces when placing lacebacks on two separate occasions. [ABSTRACT FROM AUTHOR]

As an innovative approach to overcome the rate-limiting staging of conventional aligners, using shape memory polymers (SMPs) as aligners' materials was investigated in this in vitro study. The ability of SMPs to shape recover and consequently move tooth, upon appropriate stimuli, was evaluated on a typodont model before clinical application. The study design was to achieve 1.9 mm correction movement of an upper central incisor by one aligner after multiple steps/activation. A custom-made aligned typodont model with a movable upper central incisor was scanned. Using an orthodontic software and a 3D printer, resin-models were generated. Seven aligners of ClearX sheets (SMPs) were fabricated by thermoforming on the resin aligned model. Each aligner was tested for repositioning of the central incisor in the typodont model. The model was scanned after each step and the corrective movement was measured through the superimposition of scans. Results showed that the total correction efficiency of the SMPs' aligner was ≈93% (1.76 mm). The corrective movement was 0.94 ± 0.04 mm after the reforming step, 0.66 ± 0.07 mm after the first activation step, and 0.15 ± 0.10 mm after the second activation step. It was concluded that aligners made of SMPs could have a promising future-use in orthodontic aesthetic treatment. [ABSTRACT FROM AUTHOR]

PURPOSE: To compare the effect of relieving dental crowding by using a newly designed low frictional force single--wing bracket and conventional MBT brackets on typodont model. METHODS: Two replicated typodont models were made with a same crowded upper arch. The two different types of bracket were bound separately on two typodont models. Clinical course was simulated with warm bath. The typodont models' crowded upper arch was aligned with 0.014 NiTi. The data were analyzed for t test using SPSS12.0 software package. RESULTS: In the MBT bracket group, the degree of the dental crowding reduced 2.58mm, compared with 5.49mm in the newly designed group. Significant difference between self-ligating brackets and conventional design was found between the two groups(P<0.05). CONCLUSIONS: It is indicated that the newly designed low frictional force single -wing -bracket relieves dental crowding faster than the conventional MBT bracket on typodont model. [ABSTRACT FROM AUTHOR]

The goal of our study is to launch magnetic force-driven orthodontics. This continuous study investigated the influence of magnet position on tipping and bodily tooth movement, using 3D printing technology and digital analysis. Orthodontic typodont models (TMs) for space-closure were 3D printed to mimic maxillary central incisors. Nd-Fe-B magnets were placed in the middle third (Model-M), and the cervical third (Model-C), of the tooth. TMs, before and after movement, were digitally scanned and superimposed. The 3D digital coordinates (X, Y, and Z axes), and rotations (yaw, pitch, and roll) of the tooth crown and root, were calculated and compared between the two magnet position settings. Model-M showed higher rates of movement, but more rotation than Model-C (p < 0.01). The root apex of Model-M moved in the opposite direction of the crown (R = −0.29), indicating tipping movement. In contrast, the crown and root apex moved in the same direction (R = 0.56) in Model-C, indicating bodily movement. These patterns were confirmed in a typodont model of a moderate crowding case. The results validated that modifying the magnet position increased the amount of bodily tooth movement, and decreased rotation/tipping in an ex vivo setting. [ABSTRACT FROM AUTHOR]