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Objectives: The objective of this study was to compare the trueness and precision of three intraoral scanners (IOSs) for the digitization of dentate and edentulous maxillectomy and mandibulectomy defects in artificial models. Methods: Four representative defect models—a dentate and an edentulous maxillectomy model and a dentate and an edentulous mandibulectomy model—were used for digital scanning. After a reference scan of each model, they were scanned with three IOSs: CEREC AC Omnicam, True Definition, and cara TRIOS 3. For comparison, five conventional impressions with a polysiloxane material were taken and digitized with a laboratory scanner. The obtained data were evaluated with three-dimensional (3D) inspection software and superimposed with the reference scan data by using a best-fit algorithm. The mean absolute 3D deviations of the IOS compared to the reference data (trueness) and when comparing the datasets within the IOS (precision) were analyzed. Linear mixed models and multiple pairwise comparisons were used for statistical analyses. Results: The overall comparison of the four evaluated procedures for data acquisition showed a significant difference in trueness (p < 0.0001) and precision (p < 0.0001). The average mean trueness of the IOSs ranged from 32.17 to 204.43 µm, compared to 32.07 to 64.85 µm for conventional impressions. Here, the conventional impression and cara TRIOS 3 performed the most precisely with no significant difference. CEREC AC Omnicam achieved the worst precision. Conclusions: Using a suitable intraoral scanner, defective jaws even without teeth could be captured in satisfying accuracy. This shows the possibility to use an intraoral scanner for maxillofacial defect patients and gives a vision of using digital technology in maxillofacial prosthetics. [ABSTRACT FROM AUTHOR]

Even in digital workflows, models are required for fitting during the fabrication of dental prostheses. This study examined the influence of different parameters on the dimensional accuracy of three-dimensionally printed models. A stereolithographic data record was generated from a master model (SOLL). With digital light processing (DLP) and stereolithography (SLA) printing systems, 126 models were produced in several printing runs—SolFlex350 (S) (DLP, n = 24), CaraPrint 4.0 (C) (DLP, n = 48) and Form2 (F) (SLA, n = 54)—and their accuracy was compared with plaster and milled polyurethane models. In addition to the positioning on the build platform, a distinction was made between parallel and across arrangement of the models to the printer's front, solid and hollow models, and printing with and without support structures. For accuracy assessment, five measurement sections were defined on the model (A–E) and measured using a calibrated digital calliper and digital scans in combination with the GOM Inspect Professional software 2021. The mean deviation between the measurement methods for all distances was 79 µm. The mean deviation of the models from the digital SOLL model were 207.1 µm for the S series, 25.1 µm for the C series and 141.8 µm for the F series. While positioning did not have an influence, there were clinically relevant differences mainly regarding the choice of printer, but also individually in alignment, model structure and support structures. [ABSTRACT FROM AUTHOR]

Objectives: This study investigated the effectiveness of simulation training in improving the confidence and competency of oral and maxillofacial surgery (OMS) residents in performing orthognathic surgery (OGS). Methods: Kern's six‐step approach was applied when designing the simulation training for OMS residents. The difficulties encountered by the residents when learning OGS were considered when designing the training program. A training course consisting of didactic sessions, hands‐on training on three‐dimensional training models, and an assessment tool was implemented for OMS residents. Improvement in the confidence and competence of OMS residents in performing OGS, fidelity of the three‐dimensional models, and satisfaction with the course was evaluated. Results: All OMS residents (10/10) completed the course. The perceived difficulty in learning OGS was mainly related to the manipulation of the jawbones. While there were improvements in the median confidence and competence scores (3/5 to 4/5), only the differences in competence were found to be statistically significant (p < 0.01, Wilcoxon signed‐rank test). Improvements in confidence and competence did not correlate. The mean fidelity scores of both the maxillary and mandibular models were adequate at 3.2 out of 5. Overall, satisfaction with the course was high (5/5). Conclusions: The six‐step approach provides a guided process for educators to formulate a training course directed toward the perceived needs of students. Targeted training can significantly enhance the students' competence. Greater efforts should also be put in place to allow simultaneous developments in the students' confidence along with their competence. [ABSTRACT FROM AUTHOR]

Abstract Objectives To evaluate the accuracy of a semi-automatic 3D digital setup process in predicting the orthodontic treatment outcome achieved by labial fixed appliances. Subjects and Methods Twenty-five adult patients (18 to 24 years old) with class I malocclusion and moderate crowding were prospectively enrolled and received treatment on both jaws through the straight-wire technique. Prior to treatment commencement, a semi-automatic digital setup simulating the predicted treatment outcome was performed for each patient through Orthoanalyzer software (3Shape®, Copenhagen, Denmark) to obtain the prediction model. This was compared to the final outcome model through 3D superimposition methods. Metric variables and inspection of color-coded distance maps were used to detect how accurately the digital setup predicts the actual treatment outcome. Results The mean absolute distances (MAD) between the superimposed dental arches of the predicted and the final models were: 0.77 ± 0.13 mm following superimposition on the palate, 0.52 ± 0.06 mm following superimposition on the maxillary dental arch, and 0.55 ± 0.15 mm following superimposition on the mandibular dental arch. The MAD at the palatal reference area was 0.09 ± 0.04 mm. Visualization of color-coded distance maps indicated that the digital setup accurately predicted the final teeth position in a few cases. Almost half of the cases had posteriorly wider upper and lower dental arches and palatally/lingually positioned or inclined anterior teeth, whereas the rest still showed errors within 2–3 mm, distributed over the entire dental arches with no distinct pattern. Conclusions The accuracy of semi-automatic prediction of the labial fixed appliance treatment outcome in Class I cases with moderate crowding is not yet sufficient. While average measures showed deviations less than 1 mm, examination of individual color-coded distance maps revealed significant disparities between the simulated and the actual results.

Copyright of Mersin Üniversitesi sağlık Bilimleri Dergisi is the property of Mersin University 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.)

(1) Background: Various 3D printers are available for dental practice; however, a comprehensive accuracy evaluation method to effectively guide practitioners is lacking. This in vitro study aimed to propose an optimized method to evaluate the spatial trueness of a 3D-printed dental model made of photopolymer resin based on a special structurized dental model, and provide the preliminary evaluation results of six 3D printers. (2) Methods: A structurized dental model comprising several geometrical configurations was designed based on dental crown and arch measurement data reported in previous studies. Ninety-six feature sizes can be directly measured on this original model with minimized manual measurement errors. Six types of photo-curing 3D printers, including Objet30 Pro using the Polyjet technique, Projet 3510 HD Plus using the Multijet technique, Perfactory DDP and DLP 800d using the DLP technique, Form2 and Form3 using the SLA technique, and each printer's respective 3D-printable dental model materials, were used to fabricate one set of physical models each. Regarding the feature sizes of the simulated dental crowns and dental arches, linear measurements were recorded. The scanned digital models were compared with the design data, and 3D form errors (including overall 3D deviation; flatness, parallelism, and perpendicularity errors) were measured. (3) Results: The lowest overall 3D deviation, flatness, parallelism, and perpendicularity errors were noted for the models printed using the Objet30 Pro (overall value: 45 μm), Form3 (0.061 ± 0.019 mm), Objet30 Pro (0.138 ± 0.068°), and Projet 3510 HD Plus (0.095 ± 0.070°), respectively. In color difference maps, different deformation patterns were observed in the printed models. The feature size proved most accurate for the Objet30 Pro fabricated models (occlusal plane error: 0.02 ± 0.36%, occlusogingival direction error: −0.06 ± 0.09%). (4) Conclusions: The authors investigated a novel evaluation approach for the spatial trueness of a 3D-printed dental model made of photopolymer resin based on a structurized dental model. This method can objectively and comprehensively evaluate the spatial trueness of 3D-printed dental models and has a good repeatability and generalizability. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the accuracy of a semi-automatic 3D digital setup process in predicting the orthodontic treatment outcome achieved by labial fixed appliances. Subjects and Methods: Twenty-five adult patients (18 to 24 years old) with class I malocclusion and moderate crowding were prospectively enrolled and received treatment on both jaws through the straight-wire technique. Prior to treatment commencement, a semi-automatic digital setup simulating the predicted treatment outcome was performed for each patient through Orthoanalyzer software (3Shape®, Copenhagen, Denmark) to obtain the prediction model. This was compared to the final outcome model through 3D superimposition methods. Metric variables and inspection of color-coded distance maps were used to detect how accurately the digital setup predicts the actual treatment outcome. Results: The mean absolute distances (MAD) between the superimposed dental arches of the predicted and the final models were: 0.77 ± 0.13 mm following superimposition on the palate, 0.52 ± 0.06 mm following superimposition on the maxillary dental arch, and 0.55 ± 0.15 mm following superimposition on the mandibular dental arch. The MAD at the palatal reference area was 0.09 ± 0.04 mm. Visualization of color-coded distance maps indicated that the digital setup accurately predicted the final teeth position in a few cases. Almost half of the cases had posteriorly wider upper and lower dental arches and palatally/lingually positioned or inclined anterior teeth, whereas the rest still showed errors within 2–3 mm, distributed over the entire dental arches with no distinct pattern. Conclusions: The accuracy of semi-automatic prediction of the labial fixed appliance treatment outcome in Class I cases with moderate crowding is not yet sufficient. While average measures showed deviations less than 1 mm, examination of individual color-coded distance maps revealed significant disparities between the simulated and the actual results. [ABSTRACT FROM AUTHOR]

Key Clinical Message: This research investigates the trueness and precision of 3D printing technology in dental applications, specifically focusing on dimensional variations observed in models printed at different angles. The methodology involved importing a dental model into slicing software, adjusting its orientation, and implementing support structures for stability. Subsequently, the model underwent 3D printing five times for each orientation using appropriate equipment and underwent post‐processing steps, including cleaning, washing, and UV‐light post‐curing. The printed models were then scanned using a specialized desktop scanner for further analysis. Accuracy assessment was carried out using dedicated software, employing an algorithm for precise alignment by comparing the scanned files. Color deviation maps were utilized to visually represent variations, aiming to evaluate how positioning during printing influences the trueness and precision of 3D‐printed dental models. Trueness and precision analyses involved the Shapiro–Wilk test for normality and a one‐way ANOVA to compare means of three independent groups, with statistical analyses conducted using IBM SPSS Statistics software. The color maps derived from 3D comparisons revealed positive and negative deviations, represented by distinct colors. Comparative results indicated that models positioned at 0° exhibited the least dimensional deviation, whereas those at 90° showed the highest. Regarding precision, models printed at 0° demonstrated the highest reproducibility, while those at 15° exhibited the lowest. Based on the desired level of precision, it is recommended that printed models be produced at an inclination angle of 0°. [ABSTRACT FROM AUTHOR]

The paper presents the creation of a dental bridge through two rapid prototyping technologies, SLA and FDM. The dental bridge model was made in a dental laboratory, being used later for 3D printing, through rapid prototyping, using the two technologies, FDM and SLA.

Key Clinical Message This research investigates the trueness and precision of 3D printing technology in dental applications, specifically focusing on dimensional variations observed in models printed at different angles. The methodology involved importing a dental model into slicing software, adjusting its orientation, and implementing support structures for stability. Subsequently, the model underwent 3D printing five times for each orientation using appropriate equipment and underwent post‐processing steps, including cleaning, washing, and UV‐light post‐curing. The printed models were then scanned using a specialized desktop scanner for further analysis. Accuracy assessment was carried out using dedicated software, employing an algorithm for precise alignment by comparing the scanned files. Color deviation maps were utilized to visually represent variations, aiming to evaluate how positioning during printing influences the trueness and precision of 3D‐printed dental models. Trueness and precision analyses involved the Shapiro–Wilk test for normality and a one‐way ANOVA to compare means of three independent groups, with statistical analyses conducted using IBM SPSS Statistics software. The color maps derived from 3D comparisons revealed positive and negative deviations, represented by distinct colors. Comparative results indicated that models positioned at 0° exhibited the least dimensional deviation, whereas those at 90° showed the highest. Regarding precision, models printed at 0° demonstrated the highest reproducibility, while those at 15° exhibited the lowest. Based on the desired level of precision, it is recommended that printed models be produced at an inclination angle of 0°.

Objectives: This study investigated the application of an intraoral banana peel suturing model in helping students to acquire intraoral surgical techniques. Methods: This is a self‐control study conducted from January 2021 to March 2021. An intraoral banana peel suturing model was implemented to provide oral suture experience for undergraduates majoring in stomatology. The sutures students placed in the model were photographed and evaluated blindly by a professional team using an established scoring system. Training scores were recorded before (training 1) and after 2 months of training (training 2). Linear regression was used to examine factors related to the scores. Suturing training was conducted in the School and Hospital of Stomatology at Peking University. A total of eighty‐two students in Peking University School and Hospital of Stomatology were in their fourth pre‐clinical year and followed a workshop on surgical sutures according to the curriculum. All students who should take this course were included, and the response rate was 100%. Results: The mean training 2 score (23.04 ± 3.83) was higher than the mean training 1 score (13.94 ± 3.15). The training 1 score was not significantly correlated with any of the students' general characteristics. The training 2 score was correlated with the training 1 score and the cumulative duration of practice outside of class. Conclusion: The intraoral banana peel suturing model can be used for suture training, and dental students' suture ability was improved after using the banana peel for suture practice. [ABSTRACT FROM AUTHOR]

Abstract Background A translational ex vivo perfusion-based mandibular pig model was developed as an alternative to animal experiments, for initial assessment of biomaterials in dental and maxillofacial surgery and training. This study aimed to assess the face and content validity of the novel perfusion-based model. Methods Cadaveric porcine heads were connected to an organ assist perfusion device for blood circulation and tissue oxygenation. Dental professionals and dental trainees performed a surgical procedure on the mandibula resembling a submandibular extraoral incision to create bone defects. The bone defects were filled and covered with a commercial barrier membrane. All participants completed a questionnaire using a 5-point Likert scale to assess the face and content validity of the model. Validation data between the two groups of participants were compared with Mann–Whitney U test. Results Ten dental professionals and seven trainees evaluated the model for face and content validity. Participants reported model realism, with a mean face validity score of 3.9 ± 1.0 and a content validity of 4.1 ± 0.8. No significant differences were found for overall face and content validity between experts and trainees. Conclusion We established face and content validity in a novel perfusion-based mandibular surgery model. This model can be used as an alternative for animal studies evaluating new biomaterials and related dental and maxillofacial surgical procedural training.

Abstract Objective Diagnostic casts are one of the standard components of orthodontic records. But they have several drawbacks such as the need for physical space for storage and the risk of breaking due to their brittle composition. Today, the digitalization of orthodontic models is a progress in orthodontics. The purpose of this study was to compare and evaluate common orthodontic linear measurements on plaster casts and digital 3D models using Maestro 3D ortho studio® scanner and software (AGE Solutions®, Pontedera, Italy). Materials and Methods Study casts of 30 orthodontic patients were selected. Tooth width, space analysis, Bolton analysis, overjet, overbite, and linear measurements of dental arch dimensions were performed by two examiners on plaster casts and digital models. Statistical Analysis Intra‐ and interexaminer agreements were evaluated in both manual and digital methods and paired t test was used for evaluating the agreement between the manual and digital measurement. The significance level was set at 0.05. Results The intraexaminer agreement was excellent (ICC > 0.75) for most variables in both manual and digital methods. The correlation between the two examiners was significant (p

Based on the hypothesis that the fabrication of dental models using fused deposition modeling and poly-lactic acid (PLA), followed by recycling and reusing, would reduce industrial waste, we aimed to compare the accuracies of virgin and recycled PLA models. The PLA models were recycled using a crusher and a filament-manufacturing machine. Virgin PLA was labeled R, and the first, second, and third recycles were labeled R1, R2, and R3, respectively. To determine the accuracies of the virgin and reused PLA models, identical provisional crowns were fitted, and marginal fits were obtained using micro-computed tomography. A marginal fit of 120 µm was deemed acceptable based on previous literature. The mesial, distal, buccal, and palatal centers were set at M, D, B, and P, respectively. The mean value of each measurement point was considered as the result. When comparing the accuracies of R and R1, R2, and R3, significant differences were noted between R and R3 at B, R and R2, R3 at P, and R and R3 at D (p < 0.05). No significant difference was observed at M. This study demonstrates that PLA can be recycled only once owing to accuracy limitations. [ABSTRACT FROM AUTHOR]

Abstract Background Despite many advances in dentistry, no objective and quantitative method is available to evaluate gingival shape. The surface curvature of the optical scans represents an unexploited possibility. The present study aimed to test surface curvature estimation of intraoral scans for objective evaluation of gingival shape. Methods The method consists of four main steps, i.e., optical scanning, surface curvature estimation, region of interest (ROI) definition, and gingival shape analysis. Six different curvature measures and three different diameters were tested for surface curvature estimation on central (n = 78) and interdental ROI (n = 88) of patients with advanced periodontitis to quantify gingiva with a novel gingival shape parameter (GS). The reproducibility was evaluated by repeating the method on two consecutive intraoral scans obtained with a scan-rescan process of the same patient at the same time point (n = 8). Results Minimum and mean curvature measures computed at 2 mm diameter seem optimal GS to quantify shape at central and interdental ROI, respectively. The mean (and standard deviation) of the GS was 0.33 ± 0.07 and 0.19 ± 0.09 for central ROI using minimum, and interdental ROI using mean curvature measure, respectively, computed at a diameter of 2 mm. The method’s reproducibility evaluated on scan-rescan models for the above-mentioned ROI and curvature measures was 0.02 and 0.01, respectively. Conclusions Surface curvature estimation of the intraoral optical scans presents a precise and highly reproducible method for the objective gingival shape quantification enabling the detection of subtle changes. A careful selection of parameters for surface curvature estimation and curvature measures is required.

Background: A translational ex vivo perfusion-based mandibular pig model was developed as an alternative to animal experiments, for initial assessment of biomaterials in dental and maxillofacial surgery and training. This study aimed to assess the face and content validity of the novel perfusion-based model. Methods: Cadaveric porcine heads were connected to an organ assist perfusion device for blood circulation and tissue oxygenation. Dental professionals and dental trainees performed a surgical procedure on the mandibula resembling a submandibular extraoral incision to create bone defects. The bone defects were filled and covered with a commercial barrier membrane. All participants completed a questionnaire using a 5-point Likert scale to assess the face and content validity of the model. Validation data between the two groups of participants were compared with Mann–Whitney U test. Results: Ten dental professionals and seven trainees evaluated the model for face and content validity. Participants reported model realism, with a mean face validity score of 3.9 ± 1.0 and a content validity of 4.1 ± 0.8. No significant differences were found for overall face and content validity between experts and trainees. Conclusion: We established face and content validity in a novel perfusion-based mandibular surgery model. This model can be used as an alternative for animal studies evaluating new biomaterials and related dental and maxillofacial surgical procedural training. [ABSTRACT FROM AUTHOR]

Dentoskeletal changes caused by the long-term use of mandibular advancement devices (MADs) for obstructive sleep apnea (OSA) have rarely been investigated in Japan. We assessed the long-term dentofacial morphological changes in 15 Japanese patients with OSA who used two-piece MADs for an average of 4 years. Lateral cephalography analyses were performed initially and 4 years later (T1). The dental assessment included overjet, overbite, upper anterior facial height, lower anterior facial height (LAFH), total anterior facial height (TAFH), and anterior facial height ratio. Dental casts were digitized and analyzed using a 3D scanner. Changes in the apnea hypopnea index (AHI) and other sleep-assessment indices were assessed using polysomnography and out-of-center sleep testing. Radiography revealed lingual inclination of the maxillary central incisors, labial inclination of the mandibular central incisors, clockwise rotation of the mandible, and an increase in the TAFH and LAFH at T1. In the dental cast analysis, the diameter width and palatal depth tended to decrease and increase, respectively. There was a significant decrease in the AHI and other sleep assessment indices after using the MADs for approximately 4 years. However, these findings do not provide a strong basis and should be interpreted cautiously. Future studies should have a larger sample size and should further investigate the long-term occlusal and dental changes caused by the original MADs in Japanese patients with OSA. [ABSTRACT FROM AUTHOR]

This paper presents the work steps required to create parts - dental models - on a 3D printer, models that are generated by using CAD and CAM programs. The models studied are STL files that are then processed in CAD and CAM for their printing. The printed models and their simulation were made for a material known as PLA, a material that is not used in the dental field, the printed models having only a didactic and theoretical role. [ABSTRACT FROM AUTHOR]

Objective: Diagnostic casts are one of the standard components of orthodontic records. But they have several drawbacks such as the need for physical space for storage and the risk of breaking due to their brittle composition. Today, the digitalization of orthodontic models is a progress in orthodontics. The purpose of this study was to compare and evaluate common orthodontic linear measurements on plaster casts and digital 3D models using Maestro 3D ortho studio® scanner and software (AGE Solutions®, Pontedera, Italy). Materials and Methods: Study casts of 30 orthodontic patients were selected. Tooth width, space analysis, Bolton analysis, overjet, overbite, and linear measurements of dental arch dimensions were performed by two examiners on plaster casts and digital models. Statistical Analysis: Intra‐ and interexaminer agreements were evaluated in both manual and digital methods and paired t test was used for evaluating the agreement between the manual and digital measurement. The significance level was set at 0.05. Results: The intraexaminer agreement was excellent (ICC > 0.75) for most variables in both manual and digital methods. The correlation between the two examiners was significant (p <.05) for most manual and digital measurements. The differences between the manual and digital measurements, although maybe statistically significant, were not clinically significant for most variables. Conclusion: The use of "Maestro 3D" (AGE Solutions, Pontedera, Italy) scanner and software was acceptable for orthodontic diagnostic measurements instead of study casts. [ABSTRACT FROM AUTHOR]

Objective: Most endodontic diseases are bacterium-mediated inflammatory or necrotic process induced by contaminated dental pulp. Although great advances are being performed to obtain more efficient antibacterial strategies for persistent infections, most studies lack of representative models to test their antibacterial effects and their outcomes cannot be promptly translated to clinical practice. Therefore, this study aimed to refine an ex vivo endodontic biofilm model combining human tooth, computer guided design and 3D printing to obtain a more reproducible and predictable model., Methods: Monoradicular teeth were cut using three different methods: hand-held (HCC), mechanical precision (MPC) and computer aid guided cutting (CGC). Then, blocks were reassembled. The different model preparations were assessed in terms of dimensional tolerance, surface analysis, liquid tightness and Enterococcus faecalis biofilm development for 21 days, which was studied by metabolic assays and confocal microscopy. Then, the proposed model was validated using different commercial disinfecting treatments., Results: CGC exhibited significantly lower deviation and surface without defects compared to HHC and MPC, leading to superior liquid tightness. Similarly, mature biofilms with high metabolic activity and vitality were observed in all conditions, CGC showing the lowest variation. Regarding the model validation, all antibacterial treatments resulted in the complete eradication of bacteria in the standard 2D model, whereas commercial treatments exhibited varying levels of efficacy in the proposed ex vivo model, from moderately reduction of metabolic activity to complete elimination of biofilm., Conclusions: The novel guided approach represents a more reliable, standardized, and reproducible model for the evaluation of endodontic disinfecting therapies., Clinical Significance: During antibacterial treatment development, challenging 3D models using teeth substrates to test antibacterial treatments novel guided approach represents a more reliable, standardized, and reproducible model for the evaluation of endodontic disinfecting therapies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: Despite many advances in dentistry, no objective and quantitative method is available to evaluate gingival shape. The surface curvature of the optical scans represents an unexploited possibility. The present study aimed to test surface curvature estimation of intraoral scans for objective evaluation of gingival shape. Methods: The method consists of four main steps, i.e., optical scanning, surface curvature estimation, region of interest (ROI) definition, and gingival shape analysis. Six different curvature measures and three different diameters were tested for surface curvature estimation on central (n = 78) and interdental ROI (n = 88) of patients with advanced periodontitis to quantify gingiva with a novel gingival shape parameter (GS). The reproducibility was evaluated by repeating the method on two consecutive intraoral scans obtained with a scan-rescan process of the same patient at the same time point (n = 8). Results: Minimum and mean curvature measures computed at 2 mm diameter seem optimal GS to quantify shape at central and interdental ROI, respectively. The mean (and standard deviation) of the GS was 0.33 ± 0.07 and 0.19 ± 0.09 for central ROI using minimum, and interdental ROI using mean curvature measure, respectively, computed at a diameter of 2 mm. The method's reproducibility evaluated on scan-rescan models for the above-mentioned ROI and curvature measures was 0.02 and 0.01, respectively. Conclusions: Surface curvature estimation of the intraoral optical scans presents a precise and highly reproducible method for the objective gingival shape quantification enabling the detection of subtle changes. A careful selection of parameters for surface curvature estimation and curvature measures is required. [ABSTRACT FROM AUTHOR]

Abstract Background The aim of this study was to appraise a recently developed preparedness model for the provision of oral health care during a threat such as the COVID-19 pandemic from the perspectives of oral health care providers, administrators/staff, and patients. Methods An exploratory qualitative inquiry via at-a-distance semi-structured interviews and group discussions engaged a purposefully selected sample of oral health care workers and patients in British Columbia (BC), Canada. Participants were asked to appraise a preparedness model by considering how to prepare for oral care during a pandemic, while answering open-ended questions about the model content and visual presentation. Interviews and group discussions occurred between April 2020 and January 2021, were audio recorded, and transcribed verbatim. An inductive coding process was used to identify themes, subthemes, and categories of information until saturation was achieved. Results Seventy-four participants, including 19 dentists, 15 dental hygienists, 10 certified dental assistants, 9 administrators, and 21 patients, suggested modifications to the recently developed preparedness model. Individual interviews (41 participants) and group discussions (33 participants in groups ranging from 2 to 9 attendees each) lasted for an average of 53 min. Eighty-four hours of audio recordings led to more than 1110 single-spaced pages of transcripts. The thematic analysis identified 82 codes, 12 categories, and four main themes: life-long learning, critical thinking, personal and professional risk, and patient-centred care. These themes were understood within provider characteristics and social and environmental contexts. Participants highlighted the need for the model to focus on information and communication, developing awareness and understanding, inferring risks, and performing oral health care during a threat such as a pandemic or disease outbreak. A modified portrayal of the model was suggested to better represent participants’ perspectives. Conclusion A recently developed preparedness model for the provision of dental care during an unfolding threat like the COVID-19 pandemic was appraised and modified by oral health care workers. Future studies are warranted to evaluate the modified model for use in the event of another unfolding threat collaboratively with providers, patients and stakeholders.

Copyright of International Journal of Computerized Dentistry is the property of Quintessence Publishing Company Inc. 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.)

Purpose: An essential of successful dental prosthesis is dental models. Voids present in dental models decreases accuracy and strength. This study investigates void formation in models fabricated by a new technique. The technique described in the study was based upon increasing soaking time of gypsum powder in water. Materials and methods: Voids in hand mixed, hand mixed after a soaking time of 1.5 minutes and vacuum mixed samples were examined. The voids were counted via a stereomicroscope and diameters of voids were recorded in 2 categories (0.01-0.05mm, 0.051-0.1mm). The amounts of voids were compared between the samples prepared with 3 methods. Results: The samples prepared by conventional hand mixing method had the highest total number of voids and smaller voids. There was no significant difference between the amount of voids in the samples prepared by soaking powder in water and by mixing under vacuum. Conclusion: Soaking gypsum powder in water for 1.5 minutes before mixing may be an alternative to mixing gypsum under vacuum to avoid void formation in dental models.

Introduction: Malocclusion, a common dental issue in children, necessitates early intervention to mitigate future orthodontic challenges. Predictive methodologies like Tanaka and Johnston analysis (TJA) and Boston University approach (BUA) aid in mixed and primary dentition analysis for optimal treatment planning. This study aimed to compare TJA and BUA in predicting the mesiodistal width of unerupted permanent canines and premolars and assess gender-based variations., Materials and Methods: A cross-sectional study involving 120 children (7-11 years) was conducted at Chettinad Dental College and Research Institute, Chennai, Tamil Nadu, India. Dental models were analyzed using TJA and BUA methods. The mean predicted values of permanent canines and premolars were calculated for both approaches in the upper and lower dental arches. Pearson correlation coefficients were calculated to assess the relationship between TJA and BUA predictions, and statistical significance was determined., Results: Both TJA and BUA exhibited strong positive correlations in predicting dimensions, with slight gender-based variations. TJA predicted values for permanent canines and premolars in the upper arch were 21.13 ± 0.50 and 21.32 ± 0.39, respectively, whereas for BUA, they were 21.45 ± 0.42 and 21.67 ± 0.38, respectively. In the lower arch, TJA predicted values were 20.88 ± 0.63 for canines and premolars combined, while BUA predicted 21.02 ± 0.58. Significant differences were observed only in the upper arch predictions ( p = 0.001)., Conclusion: Tanaka and Johnston analysis and BUA are valuable in mixed dentition analysis, offering insights into space availability for orthodontic treatment planning. BUA serves as a reliable substitute for TJA when fully erupted permanent incisors are absent, emphasizing the importance of tailored predictive methods in interceptive orthodontics. Model analysis remains pivotal for informed treatment decisions, ensuring optimal dental health outcomes., How to Cite This Article: Balakrishnan P, Srinivasan D, Senthil Eagappan AR, et al. Comparison between Tanaka-Johnston and Boston University Approach for Prediction of Mesiodistal Width of Canines and Premolars in Mixed Dentition Children: A Cross-sectional Study. Int J Clin Pediatr Dent 2024;17(9):976-980., Competing Interests: Source of support: Nil Conflict of interest: NoneConflict of interest: None, (Copyright © 2024; The Author(s).)

Printing dental models with hollow design can reduce resin usage, but the accuracy must be considered. The purpose of this study was to evaluate the accuracy of hollow models manufactured by a liquid crystal display (LCD) printer with differences in thickness and the presence of a grid. The 10 different designs of hollow models consisted of hollow with grid (group G) and hollow without grid (group H), and each group was divided by thickness (1.0, 1.5, 2.0, 2.5, and 3.0 mm). Including solid design as control, all models were printed by LCD printer. Trueness and precision were evaluated. The root-mean-square error (RMSE) and average were used in statistical analysis. The interaction of two factors was investigated by two-way ANOVA. One-way ANOVA with Dunnett T3 was used to compare deviation among the groups (ɑ=0.05). The results showed that thickness affected both trueness and precision, but the presence of grid affected only trueness of models. The trueness of hollow with grid or nongrid hollow with thickness of 3 mm design were significantly higher than other models and comparable to solid (p<0.05). The precision of hollow models with thickness of 3 mm was significantly higher than others and comparable to solid (p<0.05). [ABSTRACT FROM AUTHOR]

Objectives: This study aims to compare the measurements of the extraction spaces in the plaster models and digital dental models and to investigate the usability of the digital models in preventive and interceptive appliances in pediatric dentistry clinics.Material and Methods: In the dental models of 56 patients whose first molar teeth were extracted in the early period, the dental arch length of the extraction spaces were measured with a digital caliper in the plaster model (Control Group), with computer software in the digital model (Experimental Group). Measured values were compared using a t-test and statistical significance levels were determined.Results: In plaster models and digital models, the measured mean arc length of the extraction spaces were 6.94 mm and 6.83 mm, respectively. There was no statistically significant difference between the two measurement methods (p>0.05). Conclusions: The use of digital models is recommended in pediatric dentistry clinics due to shorter chair time in pediatric patients, effective treatment planning/follow-ups, reducing treatment costs and other advantages.

Objective:This study aimed to assess intra-examiner and inter-examiner reproducibility in irregularity index measurements.Methods:Twenty plaster casts of moderately crowded arches were randomly selected, and five contact point displacements (CPD) at lower anterior segment (through no. 33 to no. 43) were recorded using digital calipers on two different time points by three examiners to determine irregularity index (sum of five CPDs). To evaluate intra-examiner and inter-examiner differences, paired t-test and analysis of variance were used, respectively. Correlation analyses were performed between examiner pairs, and intra-class correlation coefficients (ICC) were determined. Statistical significance was set at p≤0.05.Results:Only a few of the repeated measurements of examiners showed significant differences (p≤0.05). All researchers were consistent in repeated measurements (p=0.000), and ICCs ranged between 0.916 and 0.986. For one CPD measurement, a statistically significant difference was detected among examiners (p=0.020). High correlation was found for inter-examiner repeatability (p

Abstract Background The aim of this study was to assess the theory that CBCT scanners can be used for a subsequent triangular mesh generation which accurately represents the actual stone model. Ten, recently acquired stone models, were used in the present study. The stone models were initially scanned with the Dental Wings 7Series dental scanner. Each stone model was then scanned using a 150-μm voxel resolution in a Planmeca Mid CBCT device with 2 sets of exposure parameters and in a Newtom VG device. The DICOM files were initially imported in Blue Sky Plan implant surgery software, segmented and then imported for computational manipulation in CloudCompare, a dedicated mesh handling software. Results For all CBCTs and for all exposure parameters, the mean (SD) difference was 0.052 (0.011) mm ranging from 0.032 to 0.070 mm with a 95% CI for the population mean of 0.052 ± 0.004 mm. Specifically, the mean (SD) difference for each device/exposure parameter tested was (1) Newtom VG = 0.040 (0.006) mm, (2) Planmeca Mid 90 = 0.057 (0.0066) mm, and (3) Planmeca Mid 80 = 0.059 (0.0063) mm. Conclusions There are differences amongst the CBCT models, whilst different exposure parameters of the same model do not seem to offer a significant advantage. The interaction between the threshold value and the imaging modality as far as the errors are concerned necessitates the careful selection of the right threshold value for the triangular mesh creation.

Background: The aim of this study was to appraise a recently developed preparedness model for the provision of oral health care during a threat such as the COVID-19 pandemic from the perspectives of oral health care providers, administrators/staff, and patients. Methods: An exploratory qualitative inquiry via at-a-distance semi-structured interviews and group discussions engaged a purposefully selected sample of oral health care workers and patients in British Columbia (BC), Canada. Participants were asked to appraise a preparedness model by considering how to prepare for oral care during a pandemic, while answering open-ended questions about the model content and visual presentation. Interviews and group discussions occurred between April 2020 and January 2021, were audio recorded, and transcribed verbatim. An inductive coding process was used to identify themes, subthemes, and categories of information until saturation was achieved. Results: Seventy-four participants, including 19 dentists, 15 dental hygienists, 10 certified dental assistants, 9 administrators, and 21 patients, suggested modifications to the recently developed preparedness model. Individual interviews (41 participants) and group discussions (33 participants in groups ranging from 2 to 9 attendees each) lasted for an average of 53 min. Eighty-four hours of audio recordings led to more than 1110 single-spaced pages of transcripts. The thematic analysis identified 82 codes, 12 categories, and four main themes: life-long learning, critical thinking, personal and professional risk, and patient-centred care. These themes were understood within provider characteristics and social and environmental contexts. Participants highlighted the need for the model to focus on information and communication, developing awareness and understanding, inferring risks, and performing oral health care during a threat such as a pandemic or disease outbreak. A modified portrayal of the model was suggested to better represent participants' perspectives. Conclusion: A recently developed preparedness model for the provision of dental care during an unfolding threat like the COVID-19 pandemic was appraised and modified by oral health care workers. Future studies are warranted to evaluate the modified model for use in the event of another unfolding threat collaboratively with providers, patients and stakeholders. [ABSTRACT FROM AUTHOR]

Copyright of European Oral Research is the property of Istanbul University, Faculty of Dentistry 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.)

The purpose of this study was to evaluate the accuracy of a dental model fabricated using the CAD/CAM milling method and the 3D printing method. Materials and Method: This study was conducted in sequence of the digitization of the master model using an intraoral scanner, the manufacturing of working models (milling model, Multi-jet printing model and Color-jet printing model) by using the scan data of the master model, the digitization of the working model by using a laboratory scanner, the superimposition of the digital data of the master model and working models using inspection software, and 3-dimensional analysis. Ten measurements per group were done by one practitioner. One-way ANOVA and Tukey’s post-hoc test were performed to compare the difference between the three groups. Results: The overall difference in models caused by the manufacturing method was measured as 73.05μm±9.64μm, 84.52μm±4.78μm, and 96.05μm±5.43μm in the milling group, Multi-jet printing group and Color-jet printing group, respectively. The difference according to the shape of the teeth, the abutment teeth among the three parts was recorded with the lowest values as 19.18±2.08μm, 77.10±7.48μm, and 56.63±4.58μm. Conclusions: Dental models manufactured by the CAD/CAM milling method presented superior accuracy over the models manufactured by the 3D printing method. Therefore, the use of optimized CAD software and appropriate materials is crucial for the fabrication accuracy of dental models.

Objective: This study aimed to assess intra-examiner and inter-examiner reproducibility in irregularity index measurements. Methods: Twenty plaster casts of moderately crowded arches were randomly selected, and five contact point displacements (CPD) at lower anterior segment (through no. 33 to no. 43) were recorded using digital calipers on two different time points by three examiners to determine irregularity index (sum of five CPDs). To evaluate intra-examiner and inter-examiner differences, paired t-test and analysis of variance were used, respectively. Correlation analyses were performed between examiner pairs, and intra-class correlation coefficients (ICC) were determined. Statistical significance was set at p=0.05. Results: Only a few of the repeated measurements of examiners showed significant differences (p=0.05). All researchers were consistent in repeated measurements (p=0.000), and ICCs ranged between 0.916 and 0.986. For one CPD measurement, a statistically significant difference was detected among examiners (p=0.020). High correlation was found for inter-examiner repeatability (p<0.05), and ICCs ranged between 0.739 and 0.984. But when the difference of 1.5 mm among measurements was set as clinically relevant, the percentages of these values for repeated measures were 15%, 5%, and 45% for examiner 1, 2, and 3, respectively. These percentages were 25%, 80%, and 65% for examiner pairs. Conclusion: Irregularity index may be a misleading index to determine anterior alignment especially when measuring small CPD. [ABSTRACT FROM AUTHOR]

Introduction: Root canal therapy is one of the most important treatments for oral and dental health. To a large extent, the success of treatment is dependent on endodontic treatment errors, and since the treatment errors are affected by the type of dental education, the aim of this study was to compare the prevalence of errors during root canal treatment by students, entering the university in 2010-2012, who were trained with and without the use of a head phantom in the Faculty of Dentistry, Isfahan University of Medical Sciences. Materials & Methods: In this descriptive-analytical study (historical cohort), 400 records were collected from the students entering the university in 2010, who were trained without a head phantom, and 400 cases related to students entering the university in 2012, who were trained with a head phantom. The records were first coded by one of the members of the admission department and then examined by two researchers for the root canal errors during the stages of access cavity preparation, root canal preparation and obturation of the root canals. These errors were collected in a double-blind manner and analyzed with SPSS 20, using Chi-squared test. Statistical significance was set at p value < 0.05. Results: In this study, root canal treatments rendered by dental students of Isfahan University of Medical Sciences were proper in 67.5% of the cases and the prevalence of root canal treatment error was 32.5% among students. The highest frequency of root canal errors among students was related to overfilling (43.9%) and the least error was related to furcal perforation (0.37%). The prevalence of root canal treatment errors among students entering the university in 2010 and 2012 were 41.6% and 24.4%, respectively. Conclusion: The present study showed that the prevalence of endodontic treatment errors by students trained with a head phantom was significantly less than that by those who were trained without a head phantom. Therefore, it can be concluded that the teaching of dental students using head phantoms can reduce root canal treatment errors by students. [ABSTRACT FROM AUTHOR]

Copyright of International Journal of Computerized Dentistry is the property of Quintessence Publishing Company Inc. 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.)

We here report the photosensitive nanocomposites as the new rapid prototyping materials. The nanocomposites are prepared using the properly surface-modified sepiolite nanofibers, graphene oxide, TiO and SiO nanoparticles as the reinforcing fillers in the epoxy-based resin. These nanocomposites are investigated about the mechanical properties, viscosity and light absorption. By fitting the rheological test results into the Krieger-Dougherty equation, the influences of the different-shaped fillers on the material viscosity and the maximum packing fraction of the fillers are obtained. The extinction coefficients of the inorganic fillers are obtained using UV-Vis spectroscopy. The mechanical properties of the nanocomposites are improved due to the surface-modified inorganic fillers. It is found that the as-prepared materials are appropriate for stereolithography and digital light processing, with which we succeed in fabricating the dental model of high dimensional accuracy. [ABSTRACT FROM AUTHOR]

Objective: To compare different stainless steel (SS) saw blades in terms of time taken to cut a block of plaster, roughness of the sawed plaster surface and sawing efficacy of blades in terms of challenge to cut plaster. Materials and methods: 40 participants of different dental specialties volunteer in the study. Each participant was given a standard plaster block to cut with six different saw blades fitted in coping dental saw. Time to cut a complete vertical slice of plaster, smoothness of the sawed surfaces and challenge to cut efficacy of blades were evaluated by using descriptive analysis. A Kruskal-Wallis H test was used to evaluate whether statistically significant difference exists between different saw blades in terms of time efficacy and smoothness of sawed surface. A one-way ANOVA was used to analyze challenge to cut efficacy of different blades. Post Hoc analysis was also used to evaluate multiple comparisons in sawing efficacy in terms of challenge to cut of different blades. Results: There was statistically significant difference between blades in terms of time efficacy and challenge to cut efficacy with hardened stainless steel blade having 17 teeth per inch (TPI) was more effective than other blades. Though blade A having 40 TPI performed better in terms of surface smoothness but there was no statistically significant difference between different blades in this regard. Conclusion: Hardened stainless steel blades should be used for plaster model cutting. Dental saw having 17 TPI performs better than other saws for plaster model cutting. [ABSTRACT FROM AUTHOR]

Objectives: We investigated and compared the errors generated by multislice computed tomography (MSCT), cone-beam computed tomography (CBCT), and digital dental casts when used to provide digital data about dental structures. Methods: Ten A20 skull models were scanned with MSCT and CBCT, and dental plaster cast models were optically scanned in three dimensions. The maxillary dental area was then compared. The distance between the three-dimensional scan data of the skull and each set of digital dental data were measured. Reference data were then overlapped with the experimental digital model using surface-based registration. The distance of errors was measured with the shortest distance measurement function. The distances between each experimental digital model and the reference scan data were measured, and error values were determined for all maxillary teeth and each tooth surface area. Errors were measured for all teeth from the central incisors to the second molar on both the left and right sides. Errors were measured from the mesial, distal, and labial surfaces and the tooth cusp tip area for each tooth. Results: The digital dental casts had the smallest error ( p < 0.001). The error in the digital dental casts (mean ± standard deviation) was 0.10 ± 0.12 mm. The CBCT error was 0.34 ± 0.38 mm, which was significantly greater than the MSCT error (0.19 ± 0.16 mm) ( p < 0.001). Conclusions: We recommend the use of digital dental casts with digital dental imaging for three-dimensional measurement of the dental area because this technique had the smallest errors. [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.)

The article provides information on assessment of dental arch relationships and use of intraoral 3D scanning or dental impressions in cleft care. Topics discussed include evaluation of dental impression using plaster models, modified Huddart Bodenham (MHB), interexaminer reliability for dentistry approach.