Students' perception of three-dimensionally printed teeth in endodontic training.

INTRODUCTION: In endodontic education, there is a need for thorough training prior to students embarking on clinical treatment. The aim of this study was to use three-dimensional printing technology to create a new model and to compare its suitability for training purposes with resin blocks and extracted teeth. MATERIALS AND METHODS: Multi-jet-modelling (MJM) produced the 3D model replicating a common difficulty in root-canal morphology. An evaluation study comprising 88 students was run in the sixth semester (summer 2018 and winter 2018/2019). A new questionnaire assessed students' perception of training models and educational environment. Welch's t-test analysed significant differences. RESULTS: The most pronounced differences between models were noted when rating material hardness, radiopacity, root-canal configuration and suitability for practising. Students estimated their learning outcome as greater with 3D-printed teeth compared to resin blocks. Three-dimensionally printed teeth received significantly lower ratings with regard to enthusiasm, the learning of fine motor skills and spatial awareness, when compared to human teeth (p ≤ .001). However, 3D-printed teeth were appreciated for additional benefits, such as their cleanliness, availability and standardisation of training opportunities with complex root-canal configurations. CONCLUSION: Students preferred extracted human teeth to 3D-printed teeth with respect to their physical characteristics and training experience. However, educational advantages may compensate for the shortcomings. The new questionnaire proved both adequate and accurate to assess the models and educational environment in endodontic training. The new 3D-printed teeth enhanced the learning opportunities.

Guided endodontics: a comparative in vitro study on the accuracy and effort of two different planning workflows.

AIM: To compare the accuracy and effort of digital workflow for guided endodontic access (GEA) procedures using two different software applications in 3D-printed teeth modeled to simulate pulp canal obliteration (PCO) in vitro. MATERIALS AND METHODS: 32 3D-printed incisors with simulated PCO were fabricated and mounted, four each on maxillary and mandibular study arches. Cone beam computed tomography (CBCT) and 3D surface scans were matched and used to virtually plan and prepare GEA by one operator using two different methods: 1) CoDiagnostiX (CDX; Dental Wings) with 3D-printed templates, and 2) Sicat Endo (SE; Sicat) with subtractive CAD/CAM-manufactured templates. Postoperative CBCT and virtual planning data were superimposed for analysis. Accuracy was assessed by measuring the discrepancies between planned and prepared cavities at the tip of the bur (three spatial dimensions, 3D vector, angle). Virtual planning effort was defined as the time and number of computer clicks. A 95% confidence interval (CI) was computed for each sample. RESULTS: SE successfully located root canals for GEA in 16/16 cases (100%) and CDX in 15/16 cases (94%). SE resulted in less mean deviation at the tip of the bur with regard to distance in the labial-oral direction (0.12 mm), 3D vector (0.35 mm), and angle (0.68 degrees) compared with CDX (0.54 mm, 0.74 mm, 1.57 degrees, respectively; P < 0.001). CDX required less mean planning time and effort for each four-tooth arch (10 min 50 s, 107 clicks) than SE (20 min 28 s, 341 clicks; P < 0.05). CONCLUSIONS: Both methods enabled rapid drill path planning, a predictable GEA procedure, and the reliable location of root canals in teeth with PCO without perforation.

Impact of specific orthodontic parameters on the oral health-related quality of life in children and adolescents : A prospective interdisciplinary, multicentre, cohort study.

PURPOSE: The aim of the present study was to analyse the impact of specific orthodontic findings on oral health-related quality of life (OHRQoL) when taking into consideration age and psychological factors in children and adolescents. METHODS: In all, 250 children and adolescents with an indication for orthodontic diagnostics were recruited using a multicentre study design. Using validated and internationally acknowledged questionnaires, we assessed OHRQoL, health-related quality of life (HRQoL), self-esteem and behavioural problems. We also examined a selection of specific orthodontic findings using photos, model casts and cephalometric analyses, and investigated the impact of these parameters on OHRQoL using simple linear regression analyses. Thereafter, we added all the significant specific orthodontic and psychological parameters to a multiple linear regression model using a stepwise forwards selection procedure. RESULTS: We were able to identify different specific orthodontic findings that have a significant impact on OHRQoL. These were the type of lip closure, the position of the chin, the Little-index of the upper jaw, the overjet, the overbite and the ANB angle. Moreover, we were able to demonstrate that psychological and some specific orthodontic parameters have a significant impact on OHRQoL. CONCLUSION: Specific orthodontic findings have a significant impact on patients' perceived OHRQoL. Further longitudinal studies are required to investigate whether the treatment and correction of these malocclusions also improve the OHRQoL of children and adolescents.

Correlation between oral health-related quality of life and orthodontic treatment need in children and adolescents-a prospective interdisciplinary multicentre cohort study.

PURPOSE: Oral health-related quality of life (OHRQoL) is a construct for assessing the self-perceived oral health of patients. The aim of this study was to investigate the correlation between OHRQoL and orthodontic treatment need in consideration of demographic and psychological factors. PATIENTS AND METHODS: This multicentre study included 250 patients with an indication for orthodontic diagnostics. In cooperation with the Institute of Clinical Psychology at the University of Würzburg, validated and internationally acknowledged questionnaires were selected to assess OHRQoL (COHIP-G19) and health-related quality of life (HRQOL). Self-esteem and behavioural problems were taken into consideration as possible psychological factors. Orthodontic treatment need was assessed using the Index of Orthodontic Treatment Need-Dental Health Component (IOTN-DHC), the Index of Orthodontic Treatment Need-Aesthetic Component (IOTN-AC) and the Dental Aesthetic Index (DAI). Possible significant correlations between the collected parameters and OHRQoL were evaluated by means of linear regression analysis. RESULTS: Objective orthodontic treatment need (IOTN-DHC and DAI) was significantly correlated with OHRQoL. Further factors significantly influencing OHRQoL in children and adolescents were age, HRQOL, self-esteem and behavioural problems. CONCLUSIONS: Objective orthodontic treatment need significantly influences OHRQoL in children and adolescents. Further studies are required to investigate if OHRQoL may be improved by correcting misaligned teeth and jaws.