Dental Scanner Research Articles

LMVSegRNN and Poseidon3D: Addressing Challenging Teeth Segmentation Cases in 3D Dental Surface Orthodontic Scans.

The segmentation of teeth in 3D dental scans is difficult due to variations in teeth shapes, misalignments, occlusions, or the present dental appliances. Existing methods consistently adhere to geometric representations, omitting the perceptual aspects of the inputs. In addition, current works often lack evaluation on anatomically complex cases due to the unavailability of such datasets. We present a projection-based approach towards accurate teeth segmentation that operates in a detect-and-segment manner locally on each tooth in a multi-view fashion. Information is spatially correlated via recurrent units. We show that a projection-based framework can precisely segment teeth in cases with anatomical anomalies with negligible information loss. It outperforms point-based, edge-based, and Graph Cut-based geometric approaches, achieving an average weighted IoU score of 0.97122±0.038 and a Hausdorff distance at 95 percentile of 0.49012±0.571 mm. We also release Poseidon's Teeth 3D (Poseidon3D), a novel dataset of real orthodontic cases with various dental anomalies like teeth crowding and missing teeth.

The Adoption and Impact of Dental Scanners in Dental Clinics across Punjab, India: Need of the Hour - A Questionnaire Study

Background: The aim of this article was to determine the adoption and impact of dental scanners in dental clinics across Punjab, India. Materials and Methods: A questionnaire was distributed via Google Forms to 450 dental clinics to gather data on the usage, benefits, and challenges associated with dental scanners. The findings highlight the growing trend of digital dentistry and its implications for clinical practice. Results: The survey conducted across 450 clinics in Punjab revealed that 60% of clinics do not use dental scanners, highlighting a significant gap in the adoption of this technology. Among the 40% of clinics that do use dental scanners, 25% utilize intraoral scanners, 10% use extraoral scanners, and 5% employ both types. The majority of these clinics have adopted dental scanners relatively recently, with only a small percentage using them for more than five years. Conclusion: Intra Oral Scanner (IOS) system is less time consuming when compared with other conventional methods. In terms of patient benefits, it reduces pain and discomfort. Ease of communicating with patients and educate them by providing video presentations before delivering any appliance or prostheses. Advanced technology is reshaping the future of digital dentistry, not only in orthodontics but also in other fields of dentistry as well.

Radiation protection in dental imaging: Evaluating the impact of the SABA thyroid shield during panoramic and cone beam computed tomography

BackgroundDental panoramic radiography (DPR) and cone beam computed tomography (CBCT) are an imaging modalities in dentistry. However, these procedures involve exposure to ionising radiation, raising concerns about radiation-induced thyroid damage. To mitigate these risks, thyroid shields have been introduced. This study aimed to evaluate the effectiveness of the SABA thyroid shield in reducing thyroid radiation exposure during DPR and CBCT scans. MethodAn experimental study to measure surface dose in the thyroid region during (DPR) and (CBCT) scans using an Anthropomorphic Phantom and a Solid-State Detector. The attenuation percentage was calculated between radiation surface doses with and without shielding. The significance of the Saba thyroid shield was calculated using a t-test. ResultsFor DPR scans, the average surface doses in the thyroid reduced significantly from 301.1 μGy (at 85 kVp) and 170.3 μGy (at 60 kVp) to 64.43 μGy and 12.94 μGy, respectively, when the Saba thyroid shield was used. For CBCT scans, the average surface doses in the thyroid decreased significantly from 814.43 μGy (for 11 × 13 cm2 field size) and 32.40 μGy (for 5 × 5 cm2 field size) to 62.91 μGy and 12.07 μGy, respectively, with the application of the Saba thyroid shield. The maximum attenuation percentages in the thyroid for the DPR and CBCT scans were 92.40% and 92.27%, respectively. Statistically significant differences between the surface dose reduction with the Saba shield and without it was observed in both DPR scans (p < 0.0000) and CBCT scans (p < 0.0003). ConclusionThe study demonstrates that Saba thyroid shields effectively reduce doses in the thyroid region during dental DPR and CBCT scans. The dose reduction depends on tube voltage for DPR scans, field size, and its position for CBCT scans. Findings highlight the importance of using Saba thyroid shields to minimise radiation exposure and protect the thyroid gland during dental scans.

DIGITAL IMPRESSION VERSUS CONVENTIONAL IMPRESSION FROM THE POINT OF VIEW OF DENTIST PREFERENCES

Nowadays digital impression represents a new breakthrough for dental offices, since more and more dentists use dental scanners. From the point of view of the dentist's preferences, there are not many studies regarding the use of the digital impression in comparison with the conventional impression. (1) Background: The aim of this study was to make a comparison between the digital impression and the classic impression and highlight the advantages and disadvantages of using the two methods, both in terms of the patient and the dentist; (2) Methods: To fulfill the objectives of this study, the Google Forms Platform was used to distribute a questionnaire regarding digital impression and classic impression. The questionnaire included 14 questions with the possibility of choosing only one answer and was addressed to dentists. (3) Results: 42 responses were recorded to the 14 questions contained in the questionnaire; (4) Conclusions: Intraoral scanning dental impression compared to traditional impression has less effect on patient gag effect, breathing difficulties, stress and anxiety, and results in better patient perception and comfort.

Evaluating the accuracy of one-piece and three-piece 3D-printed indirect bonding transfer trays: An in vitro study.

Recent developments in computer-aided design/computer-aided manufacturing (CAD/CAM) and 3D printing have enabled the fabrication of digital indirect bonding (IDB) transfer trays. These modern products require thorough investigation. The aim of the study was to determine the accuracy of one-piece and three-piece IDB transfer trays in vitro. An initial dental scan (IDS) of a randomly selected patient with digitally positioned brackets served as the master scan (MS) for designing 16 IDB transfer trays of each type. They were 3D printed and used for bonding 448 brackets to the models. Subsequently, the models were scanned with a TRIOS® 3 Intraoral Scanner (3Shape A/S, Copenhagen, Denmark), producing actual scans (ASs). The accuracy of bracket positioning was measured digitally on both MSs and ASs. The measurements were compared to the Objective Grading System for dental casts provided by the American Board of Orthodontics (ABO). The 2 types of IDB transfer trays showed comparable accuracy. All linear errors were within the clinically acceptable range, whereas the angular measurements demonstrated significant variability, resulting in clinically unacceptable transfer errors that ranged from 3.3% to 90.3%. The study results cannot be unconditionally extrapolated to other types of IDB transfer trays due to the diversity of their properties and features. The study evaluated the in vitro accuracy of IDB transfer trays. The revealed number of errors may be even higher in vivo due to limitations in visibility, salivary flow, interference from the tongue, and difficulties in achieving a proper fit of the IDB transfer tray to the teeth.

Evaluation of the accuracy of automated tooth segmentation of intraoral scans using artificial intelligence-based software packages

The accuracy of tooth segmentation in intraoral scans is crucial for performing virtual setups and appliance fabrication. Hence, the objective of this study was to estimate and compare the accuracy of automated tooth segmentation generated by the artificial intelligence of dentOne software (DIORCO Co, Ltd, Yongin, South Korea) and Medit Ortho Simulation software (Medit Corp, Seoul, South Korea). Twelve maxillary and mandibular pretreatment dental scan sets comprising 286 teeth were collected for this investigation from the archives of the Department of Orthodontics, Faculty of Dentistry, Alexandria University. The scans were imported as standard tessellation language files into both dentOne and Medit Ortho Simulation software. Automatic segmentation was run on each software. The number of successfully segmented teeth vs failed segmentations was recorded to determine the success rate of automated segmentation of each program. Evaluation of success and/or failure was based on the software's identification of the teeth and the quality of the segmentation. The mesiodistal tooth width measurements after segmentation using both tested software programs were compared with those measured on the unsegmented scan using Meshmixer software (Autodesk, San Rafael, Calif). The unsegmented scans served as the reference standard. A total of 288 teeth were examined. Successful identification rates were 99% and 98.3% for Medit and dentOne, respectively. Success rates of segmenting the lingual surfaces of incisors were significantly higher in Medit than in dentOne (93.7% vs 66.7%, respectively; P<0.001). DentOne overestimated the mesiodistal width of canines (0.11 mm, P= 0.032), premolars (0.22 mm, P< 0.001), and molars (0.14 mm, P= 0.043) compared with the reference standard, whereas Medit overestimated the mesiodistal width of premolars only (0.13 mm, P= 0.006). Bland-Altman plots showed that mesiodistal tooth width agreement limits exceeded 0.2 mm between each software and the reference standard. Both artificial intelligence-segmentation software demonstrated acceptable accuracy in tooth segmentation. There is a need for improvement in segmenting incisor lingual tooth surfaces in dentOne. Both software programs tended to overestimate the mesiodistal widths of segmented teeth, particularly the premolars. Artificial intelligence-segmentation needs to be manually adjusted by the operator to ensure accuracy. However, this still does not solve the problem of proximal surface reconstruction by the software.

Automatic removal of soft tissue from 3D dental photo scans; an important step in automating future forensic odontology identification

The potential of intraoral 3D photo scans in forensic odontology identification remains largely unexplored, even though the high degree of detail could allow automated comparison of ante mortem and post mortem dentitions. Differences in soft tissue conditions between ante- and post mortem intraoral 3D photo scans may cause ambiguous variation, burdening the potential automation of the matching process and underlining the need for limiting inclusion of soft tissue in dental comparison. The soft tissue removal must be able to handle dental arches with missing teeth, and intraoral 3D photo scans not originating from plaster models. To address these challenges, we have developed the grid-cutting method. The method is customisable, allowing fine-grained analysis using a small grid size and adaptation of how much of the soft tissues are excluded from the cropped dental scan. When tested on 66 dental scans, the grid-cutting method was able to limit the amount of soft tissue without removing any teeth in 63/66 dental scans. The remaining 3 dental scans had partly erupted third molars (wisdom teeth) which were removed by the grid-cutting method. Overall, the grid-cutting method represents an important step towards automating the matching process in forensic odontology identification using intraoral 3D photo scans.

Evaluating the influence of palate scanning on the accuracy of complete-arch digital impressions–An in vitro study

ObjectivesTo assess the impact of including the palate and the number of images recorded during intraoral digital scanning procedure on the accuracy of complete arch scans. MethodsAn experienced operator conducted 40 digital scans of a 3D printed maxillary model and divided them into two groups: 20 with inclusion of the palate (PAL) and 20 without (NPAL). Each set of scans was performed using an intraoral scanner (IOS) (Trios 5; 3Shape A/S; Copenhagen, Denmark). The resulting STL files were imported into the Geomagic Control X software (3D Systems, Rock Hill, SC, USA) for accuracy comparison. A reference STL file was created using a 3Shape E3 laboratory scanner (3Shape Scanlt Dental 2.2.1.0; Copenhagen, Denmark). The number of images captured was recorded during the scanning procedure. ResultsIn the case of the right side no statistically significant difference in trueness was detected (84 µm ± 45.6 for PAL and 80.4 ± 40.4 µm for NPAL). In the case of the left side no significant difference in trueness was observed (215.1 ± 70.2 µm for PAL and 233.9 ± 70.7 µm for NPAL). In the case of the arch distortion a statistically significant difference in trueness was seen between the two types of scans (135.3 ± 71.9 µm for PAL and 380.4 ± 255.1 µm for NPAL). The average number of images was 831.25, and 593.8 for PAL and NPAL, respectively. ConclusionsScanning of the palatal area can significantly improve the accuracy of dental scans in cases of complete arches. In terms of the number of images, based on the current results, obvious conclusions could not be drawn, and further investigation is required. Clinical significanceScanning the palate may be beneficial for improving the accuracy of intraoral scans in dentate patients. Consequently, this should be linked to an appropriate scanning strategy that predicts palatal scanning.

Comparison of Conventional and Digital Impression Methods for Measuring Mesiodistal Teeth Dimensions: An Analytical Cross-sectional Study

Introduction: We aim to determine and compare the correlation between conventional and digital impression methods for measuring mesiodistal teeth dimensions. Methods: This cross-sectional analytical study was conducted on a total of 120 dental arch samples with less than 5 mm of tooth crowding, complete teeth on the dental arch, no missing teeth, and no fillings on the mesial or distal sides at Can Tho University of Medicine and Pharmacy. Conventional (extra-fast alginate) and digital impressions using a 3D intraoral scanner (CEREC Primescan) were taken from all participants, and the dimensions of the mesiodistal teeth were measured. Using R software, Pearson’s correlation coefficients were used to analyze the correlation between conventional and digital impression methods. Result: The pooled correlation for the maxilla was 0.8062 [95% confidence interval (CI): 0.7751–0.8334] (very strong positive correlation); for the mandibular, it was 0.7645 (95% CI: 0.7165–0.8054) (strong positive correlation), and for both jaws was 0.7863 (95% CI: 0.7581–0.8115) (strong positive correlation). Conclusion: In the Vietnamese population measurement of mesiodistal tooth width using a digital dental scanner can be used instead of conventional plaster models.

CBCT and modern intraoral scanners as tools for developing comprehensive, interdisciplinary treatment plans.

The aim of this narrative literature review is to present the possibilities of using cone beam computed tomography (CBCT) and 3D dental scanners to prepare comprehensive, interdisciplinary treatment plans. Scanners are instruments whose usage seems to be a key element of modern digital dentistry. Their importance in orthodontic treatment with overlay appliances, planning modern prosthetic treatments (CAD/CAM) and implantology cannot be overestimated. These scanners allow for accurate imaging of the tooth structures and their positioning independently in the maxilla and mandible as well as in the occlusion. As a result, dentists can plan treatment, e.g., in the case of the need to implant dental implants, prosthetic crowns or orthodontic braces. Dentistry was revolutionized to a similar extent by the introduction of CBCT to everyday diagnostics, which is the most advanced imaging technology that provides even more detailed images in 3 dimensions. Its use has enabled a wider and more precise range of diagnostics, which in turn has improved the quality of multidisciplinary treatment planning. This paper explains how scanners and CBCT can be used in orthodontics and prosthetics based on the articles found in 3 databases: PubMed, Scopus and Embase. The review included 28 articles on the aforementioned topics and was presented with a brief description of the content of each article.

ИЗУЧЕНИЕ ПРОСТРАНСТВЕННОЙ ТОЧНОСТИ МОДЕЛЕЙ ЧЕЛЮСТЕЙ В ЗАВИСИМОСТИ ОТ МЕТОДА ПОЛУЧЕНИЯ ОТТИСКА И ЕГО МАТЕРИАЛА

Methods for obtaining working and auxiliary dental impressions of patients have been revised in recent decades, which is associated with 3D scanning. At the same time, the policy of import substitution in dentistry is also developing quite actively, which is reflected in the introduction of domestic impression masses for analog prints into public health institutions.&#x0D; The aim of study. Reducing the number of complications of dental orthopedic treatment by optimizing the approach to choosing a method for obtaining a working anatomical impression.&#x0D; Methodology. Impressions of the mandible of 10 patients were obtained. 7 impressions were obtained from each patient using the most commonly used techniques, silicone impression materials and intraoral scanning. Further, jaw models of 4 types of plaster were made for each impression and scanned with an off-site dental scanner. With the help of a micrometer in the oral cavity, measurements of teeth 3.5, 4.4 and 4.2 were made according to the maximum vestibular-oral size of the clinical crown, which were taken as a standard. The reference size is compared with the dimensions obtained on digital models according to the selected parameters with an accuracy of up to thousandths of a millimeter. A statistical analysis of the data obtained was carried out.&#x0D; Results. The data obtained confirmed the manufacturer's claims about the accuracy of the impression masses. A slight decrease in the studied sizes was noted on the models obtained by intraoral scanning. Whereas on models obtained using silicone impressions, the dimensions, on the contrary, were slightly larger than the reference ones. A statistically significant difference was revealed when comparing models obtained using intraoral scanning and models obtained by laboratory scanning from analogues of jaws using silicone impressions. When comparing the data obtained with the standard, no critical differences were revealed.&#x0D; Conclusions. It is impossible to unequivocally assert the advantage of a digital or analog method of obtaining impressions in modern orthopedic dentistry. The method of obtaining an impression should be chosen depending on the indications for a particular type of treatment and clinical conditions.

Digital scanning in orthodontics: a literature review

The landscape of orthodontics is changing, and the transition to digital workflows in clinical practice has begun. As new and updated scanner models are regularly being released, it is paramount to assess the current evidence base and compare this to manufacturer claims. At present, there are limited literature reviews assessing and summarizing the clinically relevant features of dental scanners. This review summarizes key findings with respect to accuracy, patient-related outcomes and clinician experiences with digital dental scanners. CPD/Clinical Relevance: Digital scanners are an increasingly popular device in orthodontics, this article provides an up-to-date summary of the pros and cons of scanners in relation to both the patient and orthodontic clinician.

Comparative Analysis of Tooth Measurements on Conventional and Digital Study Model – Validity Reliability Study

Abstract Aim: The aim of the study was to assess the accuracy, consistency, and reproducibility of tooth measurements by comparing conventional dental cast models with their digital equivalents. Materials and Methods: The research sample consisted of 50 before-treatment, diagnostic, conventional cast models utilized for study and evaluation. Tooth measurements on the dental cast models were done using a digitized Vernier caliper (Precision, IP54). Three-dimensional (3D) model tooth measurements were obtained through scanning the conventional cast models using the Maestro 3D Dental Scanner (Italy). The comparison of validity and reliability between conventional and digital cast models was done through independent t-tests, Cronbach’s alpha test, and intraclass correlation coefficient (ICC). Results: The Independent t-test showed no statistically significant difference between conventional and digital cast models. Cronbach’s alpha test demonstrated high reliability between conventional and digital cast models, surpassing 0.9 in this study. Intraexaminer reliability (ICC) was nearly perfect agreement ranging from 0.82 to 0.99. Conclusion: The digital cast models exhibited user-friendly features and were shown to be a feasible substitute for conventional dental cast models, providing similar levels of accuracy and effectiveness. Consequently, the dental arch tooth measurements of digital cast models were equally accurate and consistent when compared to those obtained from conventional dental cast models.

Evaluation of Accuracy of Different Dental Scanner Technologies: In-Vitro Study

Evaluation of Accuracy of Different Dental Scanner Technologies: In-Vitro Study

Digital measurement method for comparing the absolute marginal discrepancy of three-unit ceramic fixed dental prostheses fabricated using conventional and digital technologies

BackgroundIn clinical practice, control of the marginal fit of fixed dental prostheses is hindered by evaluation method, which needs to be further improved to increase its clinical applicability. This study aimed to quantitatively analyze the absolute marginal discrepancy of three-unit ceramic fixed dental prostheses fabricated by conventional and digital technologies using a digital measurement method based on the digital impression technology and open source software.MethodsA digital workflow and the conventional impression combined with the lost-wax heat-pressed technique were adopted to separately fabricate 10 glass ceramic fixed dental prostheses. Three-dimensional data for the abutments, fixed dental prostheses, and fixed dental prostheses seated on the abutments, were obtained using a dental scanner. The two datasets were aligned using registration technology, specifically “multi-points registration” and “best fit alignment,” by reverse engineering software. Subsequently, the three-dimensional seated fit between the fixed dental prostheses and abutments were reconstructed. The margin of the abutment and crown was extracted using edge-sharpening and other functional modules, and the absolute marginal discrepancy was measured by the distance between the margin of the abutment and crown. One-way analysis of variance was used to statistically analyze the measurement results.ResultsUsing the digital measurement method, the mean value of absolute marginal discrepancy for fixed dental prostheses fabricated by the conventional method was 106.69 ± 6.46 μm, and that fabricated by the digital workflow was 102.55 ± 6.96 μm. The difference in the absolute marginal discrepancy of three-unit all-ceramic fixed dental prostheses fabricated using the two methods was not statistically significant (p > 0.05).ConclusionsThe digital measurement method for absolute marginal discrepancy was preliminarily established based on open source software and applied in three-unit ceramic fixed dental prostheses. The absolute marginal discrepancy of three-unit ceramic fixed dental prostheses fabricated using digital technology was comparable to that of conventional technique.

Cost-Effective Full-Color 3D Dental Imaging Based on Close-Range Photogrammetry.

Dental imaging plays a crucial role in clinical dental practice. Conventional 2D dental imaging serves general-purpose tasks, such as patient documentation, while high-precision 3D dental scanning is tailored for specialized procedures, such as orthodontics and implant surgeries. In this study, we aimed to develop a cost-effective 3D imaging technique that could bridge the gap between conventional dental photography and high-precision 3D dental scanning, with the goal of improving patient dental care. We developed a 3D imaging technique based on close-range photogrammetry and termed it close-range photogrammetry-based dental imaging (CPDI). We evaluated this technique on both in vitro dental models and in vivo teeth. For dental models, we conducted a parametric study to examine the effects of the depth of field and specular reflection on reconstruction quality. We showed that the optimal results were achieved with an f/5.6 lens and without a circular polarizer for reflection suppression. This configuration generated 3D scans with 57.7 ± 3.2% and 82.4 ± 2.7% of reconstructed points falling within ±0.1 mm and ±0.2 mm error margins, respectively. With such accuracy, these 3D dental models can faithfully represent dental morphology and features. During in vivo imaging, we were able to reconstruct high-quality 3D models of the anterior arch, further demonstrating its clinical relevance. The reconstructed models carry both 3D shapes and detail full-color surface textures, which positions CPDI as a versatile imaging tool in different areas of clinical dental care.

OrthoAligner: Image-based Teeth Alignment Prediction via Latent Style Manipulation.

In this paper, we present OrthoAligner, a novel method to predict the visual outcome of orthodontic treatment in a portrait image. Unlike the state-of-the-art method, which relies on a 3D teeth model obtained from dental scanning, our method generates realistic alignment effects in images without requiring additional 3D information as input and thus making our system readily available to average users. The key of our approach is to employ the 3D geometric information encoded in an unsupervised generative model, i.e., StyleGAN in this paper. Instead of directly conducting translation in the image space, we embed the teeth region extracted from a given portrait to the latent space of the StyleGAN generator and propose a novel {latent} editing method to discover a geometrically meaningful editing path that yields the alignment process in the image space. To blend the edited mouth region with the original portrait image, we further introduce a BlendingNet to remove boundary artifacts and correct color inconsistency. We also extend our method to short video clips by propagating the alignment effects across neighboring frames. We evaluate our method in various orthodontic cases, compare it to the state-of-the-art and competitive baselines, and validate the effectiveness of each component.

3D–3D dentition superimposition for individual identification: A study of an Eastern Chinese population

Recently, 3D dental intraoral scanning technology has been developed rapidly and applied widely in everyday dental practice. Since 3D dental scanning could provide valuable personal information, it enabled researchers to develop novel procedures for individual identification through 3D–3D dentition superimposition. This study aimed to test the applicability of this method in an Eastern Chinese population and propose a threshold for personal identification. For this purpose, 40 volunteers were recruited, and the initial 80 (upper and lower) 3D intraoral scans (IOS) were collected. After one year, 80 IOS of these volunteers were repeatedly collected. In addition, the other 120 IOS of 60 patients were extracted from the database. The 3D models were trimmed, aligned, and superimposed via Geomagic Control X software, and then the root mean square (RMS) value of point-to-point distance between the two models was calculated. The superimposition of two IOS belonging to the same individual was considered as a match, and superimposition of two IOS belonging to different individuals was considered as a mismatch. Totally, superimpositions of 80 matches and 3120 mismatches were obtained. Intra- and inter-observer errors were assessed through the calculation of relative technical error of measurement (rTEM). Mann-Whitney U test verified possible statistically significant differences between matches and mismatches (P < 0.05). The rTEM of intra- and inter-observer repeatability analyses was lower than 4.7 %. The range of RMS value was 0.05–0.18 mm in matches and 0.72–2.28 mm in mismatches without overlapping. The percentage of accurate identification reached 100 % in blind test through an arbitrary RMS threshold of 0.45 mm. The results indicated that individual identification through the 3D–3D dentition superimposition was effective in Eastern Chinese population. Successful identification could be achieved with high probability when the RMS value of the point-to-point distance of two dentitions is <0.45 mm.

3D 치아 스캔 데이터를 위한 포인트 클라우드와 메쉬 기반의 분할 모델 성능 비교

최근 3D 구강 스캔 데이터를 이용하여 치아를 자동으로 분할 및 분류하거나 치아 형상을 예측하는 등의 시도가 활발히 진행되고 있다. 본 연구에서는 치아 표면 데이터에서 각 치아를 분할하는 데에 최근에 제안된 딥러닝 기반의 3D 분할 모델들을 적용하고 그 성능을 비교 평가하였다. 비교에 사용한 모델들은 데이터 형식에 따라 point cloud 기반의 모델과 mesh 기반의 모델로 구분된다. 또한, 예측된 결과물에 후처리 작업으로 graph cut 기법을 적용하여 각 모델의 분할 성능 향상을 비교 평가하였다. 실험 결과, point cloud 기반의 PointTransformer와 mesh 기반의 MeshSNet이 가장 우수한 분할 성능을 보였고, 특히 PointTransformer는 최적의 분할로 가장 빨리 수렴하였다. 결론적으로 치아 외관을 구성하는 포인트 또는 메쉬의 인접성 정보와 Transformer의 활용이 치아 분할 성능 향상에 중요한 영향을 주는 것으로 분석된다.

Accuracy of 3-dimensional–printed customized transfer tray using a flash-free adhesive system in digital indirect bonding: An in vivo study

This paper evaluated the accuracy of a computer-aided design and manufacturing indirect bonding technique using a new customized 3D-printed transfer tray and a flash-free adhesive system for orthodontic bonding. This invivo study analyzed 106 teeth selected from 9 patients undergoing orthodontic treatment. Quantitative deviation analysis was performed to evaluate the bonding positioning errors, assessing the differences between the virtually planned and the clinically transferred bracket position after indirect bonding procedures by superimposing 3-dimensional dental scans. Estimated marginal means were evaluated for individual brackets and tubes, arch sectors, and overall collected measurements. A total of 86 brackets and 20 buccal tubes were analyzed. Among individual teeth, mandibular second molars showed the highest positioning errors, whereas maxillary incisors reported the lowest values. Considering arch sectors, the posterior areas showed greater displacements than the anterior areas, as the right side compared to the left side, with a higher error rate reported for the mandibular arch than the maxillary arch. The overall bonding inaccuracy measurement was 0.35 mm, below the clinical acceptability limit of 0.50 mm. The accuracy of a 3-dimensional-printed customized transfer tray using a flash-free adhesive system in computer-aided design and manufacturing indirect bonding was generally high, with greater positioning errors for posterior teeth.