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Background: While many denture base materials are currently available on the market, little data exists regarding their dimensional stability after exposure to the oral environment. This study aimed to evaluate the effect of thermocycling on the trueness and precision of milled, 3-dimensional (3D)-printed, and conventional digitally fabricated complete denture bases (CDBs). Methods: A completely edentulous maxillary stone model was scanned to generate a standard tessellation language (STL) file; this was imported into metal-milling-machine software (Redon Hybrid CAD-CAM metal milling machine, Redon, Turkey) to produce a metal model for fabricating 30 CDBs. These were divided into three groups (n = 10 in each) according to the construction technique: group 1, CAD-CAM milled CDBs; group 2, 3D-printed CDBs; and group 3, conventional compression molded CDBs. All CDBs were scanned after fabrication and evaluated before and after thermocycling using superimposition. The data were analyzed using a one-way ANOVA, Tukey's post hoc test, and a paired t-test. Results: The level of trueness between the CAD-CAM milled, 3D-printed, and compression molded CDBs showed significant differences before and after thermocycling (P < 0.05). Group 1 showed the highest degree of trueness before and after thermocycling, group 3 exhibited a higher degree of trueness than group 2 before thermocycling, and group 2 had a higher degree of trueness than group 3 after thermocycling. There was a significant difference in the precision for each CDB type before and after thermocycling (P < 0.05). Conclusion: The trueness of the CAD-CAM milling system in complete denture (CD) fabrication is superior to that of the 3D printing and conventional compression molding systems before and after thermocycling. Thermocycling had a significant effect on the precision of all CDB types. The compression molding system in CD construction is the most negatively affected via thermocycling with regard to the measures of trueness and precision. Clinical trial number: Not applicable, no human participants were involved. [ABSTRACT FROM AUTHOR]

Background: Posttreatment changes after orthodontic treatment are challenging. One of the main reasons for such a phenomenon is the lack of patient compliance with removable retainers especially in the maxillary arch, due to palatal coverage, deterioration of speech, decreased masticatory efficiency, and loss of retainers. Fixed retainers have been introduced to overcome patient compliance and provide longer stable results. However, teeth still show movements when a six-unit fixed retainer is in place. Thus, in this study, an eight-unit fixed retainer was evaluated in an attempt to eliminate unwanted movements. The aim of this research: was to assess short-term positional changes associated with an eight-unit extended maxillary fixed retainer. Materials and methods: A single-arm clinical trial was conducted to address the aim of the study. This research was approved by the institutional review board of the Faculty of Dentistry, Alexandria University (IORG:0008839, No-0479–8/2022). The registration date of this study was 5/06/2023. Twenty-eight patients (19.8 ± 4.5 years) who had finished the active orthodontic phase and started retention had an eight-unit extended maxillary fixed retainer that was bonded to the palatal surface of the maxillary incisors, canines, and the first premolars or the second premolars. Pre-retention and one-year post-retention intra-oral scans were made to produce STL files that were superimposed to determine the amount of tooth change. Additionally, analysis of digital casts and lateral cephalometric radiographs was performed. Results: Statistically significant changes in all planes and the rotation of teeth after one year of retention were found. The upper right lateral incisor exhibited the most evident change in the vertical plane, while the upper right central incisor exhibited the greatest change overall. Minimal changes in the cast measurements were observed. Lateral cephalometric measurements showed minimal changes after one year of retention, and these changes were not statistically significant except in the interincisal angle and the angle between the upper incisor and the line connecting the A-point to the pogonion. Conclusion: Increasing the extension of maxillary fixed retainers did not eliminate unwanted tooth movement in the first year of retention. [ABSTRACT FROM AUTHOR]

Abstract Background While many denture base materials are currently available on the market, little data exists regarding their dimensional stability after exposure to the oral environment. This study aimed to evaluate the effect of thermocycling on the trueness and precision of milled, 3-dimensional (3D)-printed, and conventional digitally fabricated complete denture bases (CDBs). Methods A completely edentulous maxillary stone model was scanned to generate a standard tessellation language (STL) file; this was imported into metal-milling-machine software (Redon Hybrid CAD-CAM metal milling machine, Redon, Turkey) to produce a metal model for fabricating 30 CDBs. These were divided into three groups (n = 10 in each) according to the construction technique: group 1, CAD-CAM milled CDBs; group 2, 3D-printed CDBs; and group 3, conventional compression molded CDBs. All CDBs were scanned after fabrication and evaluated before and after thermocycling using superimposition. The data were analyzed using a one-way ANOVA, Tukey’s post hoc test, and a paired t-test. Results The level of trueness between the CAD-CAM milled, 3D-printed, and compression molded CDBs showed significant differences before and after thermocycling (P

Abstract Background Posttreatment changes after orthodontic treatment are challenging. One of the main reasons for such a phenomenon is the lack of patient compliance with removable retainers especially in the maxillary arch, due to palatal coverage, deterioration of speech, decreased masticatory efficiency, and loss of retainers. Fixed retainers have been introduced to overcome patient compliance and provide longer stable results. However, teeth still show movements when a six-unit fixed retainer is in place. Thus, in this study, an eight-unit fixed retainer was evaluated in an attempt to eliminate unwanted movements. The aim of this research was to assess short-term positional changes associated with an eight-unit extended maxillary fixed retainer. Materials and methods A single-arm clinical trial was conducted to address the aim of the study. This research was approved by the institutional review board of the Faculty of Dentistry, Alexandria University (IORG:0008839, No-0479–8/2022). The registration date of this study was 5/06/2023. Twenty-eight patients (19.8 ± 4.5 years) who had finished the active orthodontic phase and started retention had an eight-unit extended maxillary fixed retainer that was bonded to the palatal surface of the maxillary incisors, canines, and the first premolars or the second premolars. Pre-retention and one-year post-retention intra-oral scans were made to produce STL files that were superimposed to determine the amount of tooth change. Additionally, analysis of digital casts and lateral cephalometric radiographs was performed. Results Statistically significant changes in all planes and the rotation of teeth after one year of retention were found. The upper right lateral incisor exhibited the most evident change in the vertical plane, while the upper right central incisor exhibited the greatest change overall. Minimal changes in the cast measurements were observed. Lateral cephalometric measurements showed minimal changes after one year of retention, and these changes were not statistically significant except in the interincisal angle and the angle between the upper incisor and the line connecting the A-point to the pogonion. Conclusion Increasing the extension of maxillary fixed retainers did not eliminate unwanted tooth movement in the first year of retention.

Introduction: The frontal sinus is a well-preserved structure, hence making it a potential site of choice during forensic identification. The coexistence of 2-dimensional (2D) and 3-dimensional (3D) models from imaging has gained interest for forensic usage. Despite the existing comparison between 2D and 3D models, the comparison using frontal sinus within the same patient is yet to be explored. This upsurges a key question on the morphological consistency of 3D over 2D models on the frontal sinus. This pilot study compares the consistency of frontal sinus morphology between 2D and 3D frontal sinus reconstructed models. Methods: The samples comprised 30 digital skull radiographs and CT scans of the same subject. The 3D models of the frontal sinus were reconstructed from CT scans. The 2D and 3D models were superimposed, and the congruence of the morphological features was assessed in a superimposed state using a mix and wipe method. Results: The superimposed frontal sinus morphology on the 2D and 3D models shows a perfect match of 100% in the posteroanterior view. In the lateral view, 77% of the samples failed to match. Conclusion: The 3D frontal sinus model is more recommended to evaluate the frontal sinus region compared to the 2D model. [ABSTRACT FROM AUTHOR]

Global efforts to minimise carbon dioxide emissions are also leading to attempts to use calcined clays (CC) as a partial substitute for cement in concrete. While the hydration mechanism of such CC blended cements is now well understood, the range of effective admixtures like polycarboxylate ethers (PCE) is limited. There are PCE types that promise relatively high effectiveness, but the mechanisms of action are not yet sufficiently understood. For a detailed understanding of the adsorption of such PCEs, spatially resolved studies of the binder were performed using a combination of fluorescence and scanning electron microscopy. In a comparison of two superplasticisers, the investigations have shown different sites of preferred adsorption in a CC blended system and the results can be correlated with flow tests and setting behaviour. The investigations have shown that a certain PCE type has a higher adsorption on CC and other components of a blended system in comparison to other types. LAY DESCRIPTION: Efforts to reduce carbon dioxide emissions globally are driving attempts to use calcined clays as a partial replacement for cement in concrete. Although the hardening mechanism of cements blended with calcined clays is well understood, the range of effective admixtures, such as plastisicing agents, is limited. While some plastisicing agent types show relatively high effectiveness, their mechanisms of action are not yet fully understood. To understand how these plastisicing agents interact with the compounds, fluorescence and scanning electron microscopy has been used to study this interaction. Two different plastisicing agent types have been compared and it was found that they prefer different sites of the compounds to interact with in a blended cement. These results can be correlated with flow tests and setting behaviour. The investigations have shown that one particular type of plastisicing agents has a higher affinity to calcined clay and other components of a blended system compared to other types. [ABSTRACT FROM AUTHOR]

Purpose: To study the influence of insertion depth and implant angulation on the 3D trueness of models obtained with different impression techniques. Materials and Methods: Four different reference models (model 1: parallel, depth of 1.5 mm; model 2: parallel, depth of 4 mm; model 3: 20-degree angle, depth of 1.5 mm; and model 4: 20-degree angle, depth of 4 mm) of partially edentulous maxillae were generated by altering implant angulations and subgingival depths. All scans of reference models were done with a laboratory scanner, and obtained data were exported into standard tessellation language format to be used as virtual reference images. Impressions were obtained from each reference model via three conventional techniques (closed tray [CT], non-hexed open tray [NHOT], and hexed open tray [HOT]) and one digital technique (intraoral scanning [IOS]). A total of 160 impressions were made. The reference and experimental scan data were superimposed by using the best-fit alignment algorithm. Angular (AD), linear (LD), and 3D (RMS) deviations were computed, and obtained data were statistically analyzed. Results: In premolar implant sites, AD and LD values were significantly affected by model type (P ≤ .001 for AD and LD) and impression technique (P = .001 for AD, P = .002 for LD). However, no significant interaction was detected (P = .703 for AD, P = .768 for LD). Model 1 (0.44 ± 0.25 for AD, 7.79 ± 6.29 for LD) and the NHOT technique (0.49 ± 0.43 for AD, 9.04 ± 8.14 for LD) exhibited the lowest mean AD and LD values. In molar implant sites, AD and LD values were significantly affected by model type (P ≤ .001 for AD and LD) and impression technique (P ≤ .001 for AD and LD), as well as by their interaction terms (P = .037 for AD, P = .005 for LD). Considering interaction terms, while the highest and lowest mean AD values were exhibited by IOS-model 4 (1.56 ± 0.25) and NHOT-model 2 (0.46 ± 0.28), respectively, the highest and lowest mean LD values were exhibited by CT-model 4 (41.40 ± 14.48) and NHOT-model 2 (8.03 ± 4.86), respectively. RMS estimate values were significantly influenced by model type (P ≤ .001) and impression technique (P ≤ .001), as well as by their interaction terms (P = .019). The highest and lowest mean RMS values were exhibited by IOS-model 4 (70.02 ± 4.74) and NHOT-model 2 (25.96 ± 17.67), respectively. Conclusion: In the case of angulated and deeply placed implants, splinted NHOT and HOT techniques can be recommended for better trueness. [ABSTRACT FROM AUTHOR]

Abstract Background This prospective clinical study aimed to quantitatively evaluate the surface wear of attachments and investigate the associated risk factors. Additionally, the wear values and regions of three types of commonly used attachments were explored. Methods Participants were recruited from the population of patients who received clear aligner therapy from October to December 2022. Intraoral scanning was performed on eligible participants before treatment (T0), immediately after initial bonding of attachments (T1), and at 2 months (T2), 4 months (T3), 6 months (T4), and 8 months (T5) after starting treatment. The attachment volume, average depth and regions of attachment wear were measured using superimposed digitized models. The Kruskal–Wallis test was performed to compare data between multiple groups. Multiple linear regression analyses were performed to evaluate risk factors for the volume of attachment wear. Results A total of 47 patients with 617 attachments were included. As treatment time increased, the attachment volume decreased significantly (P = 0.003). The initial attachment volume was positively related to the volume of attachment wear (β = 0.527, P

Abstract Background This study aimed to validate the availability of superimposing full-color mandibular digital models (DMs) by the morphological characteristics of vessels in extraction adult patients. Methods Twenty-eight adult patients were included, and their DMs were superimposed with pre- and posttreatment cone beam computed tomography (CBCT) and the morphological characteristics of lingual vessels. The measurements of each tooth were compared under the same coordinate system. Results The ICC results displayed exceptional agreement in intra- and interrater assessments, with scores exceeding 0.891 in the crown for intrarater agreement and scores surpassing 0.888 in the crown for interrater agreement. Furthermore, no statistically significant differences were found in the 2 superimposition methods (P > 0.05). Conclusion The morphological characteristics of vessels under the mucogingival junction in the lingual side of mandible of are stable enough for the superimposition of mandibular DMs in the adult patients undergo orthodontic treatment with premolars extraction.

Background: This prospective clinical study aimed to quantitatively evaluate the surface wear of attachments and investigate the associated risk factors. Additionally, the wear values and regions of three types of commonly used attachments were explored. Methods: Participants were recruited from the population of patients who received clear aligner therapy from October to December 2022. Intraoral scanning was performed on eligible participants before treatment (T0), immediately after initial bonding of attachments (T1), and at 2 months (T2), 4 months (T3), 6 months (T4), and 8 months (T5) after starting treatment. The attachment volume, average depth and regions of attachment wear were measured using superimposed digitized models. The Kruskal–Wallis test was performed to compare data between multiple groups. Multiple linear regression analyses were performed to evaluate risk factors for the volume of attachment wear. Results: A total of 47 patients with 617 attachments were included. As treatment time increased, the attachment volume decreased significantly (P = 0.003). The initial attachment volume was positively related to the volume of attachment wear (β = 0.527, P < 0.001). The volume of attachment wear was significantly greater in females than in males (β = 0.147, P = 0.020) and in optimized attachments than in conventional attachments (β = 0.308, P < 0.001). The wear of 3-mm rectangular attachments progressed from edges to buccal surfaces, with the deepest wear at corners of gingival edges; the wear of the optimized attachments was primarily located on surface ridges. The wear volume ratio of the optimized root control attachments was significantly greater than that of the 3-mm rectangular attachments at T3 (P = 0.011), T4 (P < 0.001), and T5 (P < 0.001). Conclusions: The volume of attachment wear increased gradually with treatment time. Sex, attachment type, and initial attachment volume were risk factors for the volume of attachment wear. The deepest wear regions of 3-mm rectangular attachments were at the corners of gingival edges, while the deepest wear regions of optimized attachments were at surface ridges. Four months after treatment, optimized root control attachments showed more relative wear than 3-mm rectangular attachments. [ABSTRACT FROM AUTHOR]

Background: This study aimed to validate the availability of superimposing full-color mandibular digital models (DMs) by the morphological characteristics of vessels in extraction adult patients. Methods: Twenty-eight adult patients were included, and their DMs were superimposed with pre- and posttreatment cone beam computed tomography (CBCT) and the morphological characteristics of lingual vessels. The measurements of each tooth were compared under the same coordinate system. Results: The ICC results displayed exceptional agreement in intra- and interrater assessments, with scores exceeding 0.891 in the crown for intrarater agreement and scores surpassing 0.888 in the crown for interrater agreement. Furthermore, no statistically significant differences were found in the 2 superimposition methods (P > 0.05). Conclusion: The morphological characteristics of vessels under the mucogingival junction in the lingual side of mandible of are stable enough for the superimposition of mandibular DMs in the adult patients undergo orthodontic treatment with premolars extraction. [ABSTRACT FROM AUTHOR]

When an unidentified skeleton is discovered, a video superimposition (VS) of the skull and a facial photograph may be undertaken to assist identification. In the first instance, the method is fundamentally a photographic one, requiring the overlay of two 2D photographic images at transparency for comparison. Presently, mathematical and anatomical techniques used to compare skull/face anatomy dominate superimposition discussions, however, little attention has been paid to the equally fundamental photographic prerequisites that underpin these methods. This predisposes error, as the optical parameters of the two comparison photographs are (presently) rarely matched prior to, or for, comparison. In this paper, we: (1) review the basic but critical photographic prerequisites that apply to VS; (2) propose a replacement for the current anatomy-centric searches for the correct 'skull pose' with a photographic-centric camera vantage point search; and (3) demarcate superimposition as a clear two-stage phased procedure that depends first on photographic parameter matching, as a prerequisite to undertaking any anatomical comparison(s). [ABSTRACT FROM AUTHOR]

This study aimed to compare the 3D skull models reconstructed from computed tomography (CT) images using three different open-source software with a commercial software as a reference. The commercial Mimics v17.0 software was used to reconstruct the 3D skull models from 58 subjects. Next, two open-source software, MITK Workbench 2016.11, 3D Slicer 4.8.1 and InVesalius 3.1 were used to reconstruct the 3D skull models from the same subjects. All four software went through similar steps in 3D reconstruction process. The 3D skull models from the commercial and open-source software were exported in standard tessellation language (STL) format into CloudCompare v2.8 software and superimposed for geometric analyses. Hausdorff distance (HD) analysis demonstrated the average points distance of Mimics versus MITK was 0.25 mm. Meanwhile, for Mimics versus 3D Slicer and Mimics versus InVesalius, there was almost no differences between the two superimposed 3D skull models with average points distance of 0.01 mm. Based on Dice similarity coefficient (DSC) analysis, the similarity between Mimics versus MITK, Mimics versus 3D Slicer and Mimics versus InVesalius were 94.1, 98.8 and 98.3%, respectively. In conclusion, this study confirmed that the alternative open-source software, MITK, 3D Slicer and InVesalius gave comparable results in 3D reconstruction of skull models compared to the commercial gold standard Mimics software. This open-source software could possibly be used for pre-operative planning in cranio-maxillofacial cases and for patient management in the hospitals or institutions with limited budget. [ABSTRACT FROM AUTHOR]

Purpose: To retrospectively compare and analyze differences in tissue displacement of edentulous arches among three‐dimensional (3D) files obtained using various impression‐making techniques. Materials and Methods: Fourteen patients who underwent prosthodontic treatment for edentulous arches at Yonsei University Dental Hospital between June 2020 and April 2023 were included in the study. Three types of 3D files were used for the evaluation of each arch: a 3D scan file of a definitive cast (Group DEF), a preliminary cast (Group PRE), and an intraoral scan file (Group IOS). The files were superimposed on a reference 3D scan file of the definitive cast group through best‐fit matching using metrology software. Seventeen measurement points (MP1‐4, RC1‐6, TB1‐2, and PPS1‐5 for the maxilla and RP1‐2, RC1‐7, BS1‐4, and LS1‐4 for the mandible) were selected for both the maxillary (n = 13) and mandibular arches (n = 6). The deviation considering the direction (DD) between the three groups and the absolute deviation (AD) between the three groups were recorded. Kruskal–Wallis and post‐hoc Mann–Whitney tests were used for statistical analyses (α = 0.05 and α = 0.0167, respectively). Results: Concerning the DD values, at the RC4 point of the maxillary arch, Group PRE exhibited significantly higher values than Groups IOS (p = 0.006) and DEF (p < 0.001), and at the RC5 point of the maxillary arch, Group IOS exhibited significantly lower values than Groups PRE (p = 0.016) and DEF (p < 0.001). Group IOS showed significantly lower DD values in the mandibular arch than Group DEF at the RP2 and RC3 points (p < 0.167). The AD values in Groups PRE and IOS significantly differed from those in Group DEF (all p < 0.001) at all measurement points but did not exhibit significant differences between each other (p > 0.05). Conclusions: Different impression‐making methods yielded different amounts of tissue displacement. The tendency of 3D files regarding tissue displacement varied at certain residual ridge crest areas and retromolar pad areas. The absolute amount of tissue displacement observed in the intraoral scan data was comparable to that observed in the preliminary casts. [ABSTRACT FROM AUTHOR]

Purpose: This prospective clinical study evaluated and compared the marginal and internal fit of crowns fabricated with an analog workflow and three different computer‐aided design and computer‐aided manufacturing (CAD–CAM) systems. Materials and methods: Twenty‐five participants in need of a single complete‐coverage molar or premolar crown were recruited in the study. Twenty‐two completed the study, and three participants dropped out. Teeth were prepared according to a standardized protocol by one operator. For each participant, one final impression was made with polyether material (PP) and three intraoral scanners: CEREC Omnicam (C), Planmeca Planscan (PM), and True Definition (TR). For the PP group, crowns were fabricated with a pressable lithium disilicate ceramic, whereas for the other three groups (C, PM, and TR), crowns were designed and milled with dedicated CAD–CAM systems and materials. Marginal (vertical and horizontal) and internal discrepancies between the crowns and tooth preparation were measured at various locations with digital superimposition software. Data was analyzed for normality with Kolmogorov–Smirnov and Shapiro–Wilk tests and then compared with one‐way ANOVA and Kruskal–Wallis tests. Results: Mean vertical marginal gap values were 92.18 ± 141.41 μm (PP), 150.12 ± 138.06 μm (C), 129.07 ± 109.96 μm (PM), and 135.09 ± 112.03 μm (TR). PP group had statistically significantly smaller vertical marginal discrepancy (p = 0.001) than all other groups, whereas no significant difference was detected among the three CAD–CAM systems (C, PM, and TR). Horizontal marginal discrepancies were 104.93 ± 111.96 μm (PP), 89.49 ± 119.66 μm (C), 113.36 ± 128.49 μm (PM), and 136.39 ± 142.52 μm (TR). A significant difference was detected only between C and TR (p < 0.0001). Values for the internal fit were 128.40 ± 49.31μm (PP), 190.70 ± 69.79μm (C), 146.30 ± 57.70 μm (PM), and 168.20 ± 86.67 μm (TR). The PP group had a statistically significant smaller internal discrepancy than C (p < 0.0001) and TR groups (p = 0.001), whereas no significant difference was found compared to the PM group. Conclusion: Posterior crowns fabricated with CAD–CAM systems showed vertical margin discrepancy greater than 120 μm. Only crowns fabricated with the conventional methodology had vertical margins below 100 μm. Horizontal marginal discrepancy was different among all groups, and only CEREC CAD–CAM was below 100 μm. Internal discrepancy was less for crowns fabricated with an analog workflow. [ABSTRACT FROM AUTHOR]

Jiajun Wu,1,2,&ast; Lei Gao,1,2,&ast; Qiao Shi,3 Chunhui Qin,4 Kai Xu,1,2 Zhaoshun Jiang,1,2 Xixue Zhang,1,2 Ming Li,5 Jianjian Qiu,6,&ast; Weidong Gu1,2,&ast; 1Department of Anesthesiology, Huadong Hospital Affiliated to Fudan University, Shanghai, 200040, People’s Republic of China; 2Shanghai Key Laboratory of Clinical Geriatric Medicine, Shanghai, 200040, People’s Republic of China; 3Department of Anesthesiology, International Peace Maternity and Child Health Hospital of China, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200030, People’s Republic of China; 4Department of Pain Management, Yueyang Integrated Traditional Chinese Medicine and Western Medicine Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai, 200437, People’s Republic of China; 5Department of Radiology, Huadong Hospital affiliated to Fudan University, Shanghai, 200040, People’s Republic of China; 6Department of Radiation Oncology, Huadong Hospital Affiliated to Fudan University, Shanghai, 200040, People’s Republic of China&ast;These authors contributed equally to this workCorrespondence: Weidong Gu; Jianjian Qiu, Email hdmz0800@163.com; qiujianjian@fudan.edu.cnPurpose: To evaluate the accuracy of mixed reality (MR)-guided visualization technology for spinal puncture (MRsp).Methods: MRsp involved the following three steps: 1. Lumbar spine computed tomography (CT) data were obtained to reconstruct virtual 3D images, which were imported into a HoloLens (2nd gen). 2. The patented MR system quickly recognized the spatial orientation and superimposed the virtual image over the real spine in the HoloLens. 3. The operator performed the spinal puncture with structural information provided by the virtual image. A posture fixation cushion was used to keep the subjects’ lateral decubitus position consistent. 12 subjects were recruited to verify the setup error and the registration error. The setup error was calculated using the first two CT scans and measuring the displacement of two location markers. The projection points of the upper edge of the L3 spinous process (L3↑), the lower edge of the L3 spinous process (L3↓), and the lower edge of the L4 spinous process (L4↓) in the virtual image were positioned and marked on the skin as the registration markers. A third CT scan was performed to determine the registration error by measuring the displacement between the three registration markers and the corresponding real spinous process edges.Results: The setup errors in the position of the cranial location marker between CT scans along the left-right (LR), anterior-posterior (AP), and superior-inferior (SI) axes of the CT bed measured 0.09 ± 0.06 cm, 0.30 ± 0.28 cm, and 0.22 ± 0.12 cm, respectively, while those of the position of the caudal location marker measured 0.08 ± 0.06 cm, 0.29 ± 0.18 cm, and 0.18 ± 0.10 cm, respectively. The registration errors between the three registration markers and the subject’s real L3↑, L3↓, and L4↓ were 0.11 ± 0.09 cm, 0.15 ± 0.13 cm, and 0.13 ± 0.10 cm, respectively, in the SI direction.Conclusion: This MR-guided visualization technology for spinal puncture can accurately and quickly superimpose the reconstructed 3D CT images over a real human spine.Keywords: mixed reality, spinal puncture, immobilization, superimposition, setup error, registration error

Herein, we used digital superimposition to evaluate the accuracy of metal frameworks for mandibular removable partial dentures fabricated using three techniques. Thirty master casts of a mandibular dentiform were categorized into three groups (n = 10) based on the framework manufacturing method: selective laser melting-based metal three-dimensional (3D) printing (SLM), digital light projection-based resin 3D printing and subsequent casting (RPC), and conventional casting (CON). The master casts were scanned twice, initially after preparation and subsequently after attaching silicone using the frameworks. These scan files were digitally superimposed to measure the silicone thickness. Statistical analysis was conducted using SPSS Statistics (Version 23.0, IBM Corp., Somers, NY, USA). One-way ANOVA and a post hoc Tukey’s multiple comparison tests were performed to determine differences among the three groups (α = 0.05). The RPC group exhibited significantly higher overall and mean internal discrepancies at rest and tissue stops than the SLM and CON groups, which exhibited statistically insignificant differences. Thus, SLM fabrication resulted in comparable accuracy to that achieved by CON, whereas sequentially performing resin 3D printing and casting induced inferior accuracy. However, all frameworks across the three groups were clinically acceptable.

While online shopping has become popular in recent years, certain problems related to customer expectations about the appearance and fitting of clothing items still need to be solved. Online customers looking for clothing products may be unsatisfied as they do not have the possibility to try on clothes and view how they would look on them. Additionally, vendors are burdened with the cost of items returned by unsatisfied customers. Augmented Reality (AR) can help vendors to attract more customers and enhance their shopping experience. Customers are more likely to be satisfied with their purchases when they can try the clothes on before purchasing them, which ultimately reduces the return costs for vendors. This paper presents an AR mobile application called Smart Fitting which was developed in order to allow online customers to try on clothing items by using 3D models virtually. The most recent AR development tools for iOS operating systems, including XCode and Unity, are utilized for creating the proposed mobile application. After an integration testing for the mobile application functions, seven target female consumers participated in the usability evaluation for this mobile application which was meant to prove its ease of use and evaluate the customers’ satisfaction. The obtained results showed that Smart Fitting can improve the users shopping experience by providing a more realistic clothes visualization than the traditional online shopping interfaces.

Abstract Background The purpose of this study was to assess morphological changes of the upper anterior alveolus after retraction of a maxillary incisor by applying three-dimensional (3D) superimposition of pretreatment (T1) and posttreatment (T2) cone-beam computed tomography (CBCT) data. Methods The study group was comprised of 28 patients with skeletal Class II malocclusion who underwent incisor retraction. CBCT data were acquired before (T1) and after (T2) orthodontic treatment. Labial and palatal alveolar thickness were assessed at the crestal, midroot and apical levels of the retracted incisors. Following three-dimensional (3D) cranial base superimposition, we performed surface modeling and inner remodeling of the labial and palatal alveolar cortex of the maxillary incisors. Paired t-tests were used to compare T0 and T1 bone thickness and volume measurements. Comparisons between labial and palatal surface modeling, inner remodeling and outer surface modeling were performed with paired t-tests in SPSS 20.0 version. Results We observed controlled tipping retraction of the upper incisor. After treatment, the alveolar thickness on the labial sides increased and the palatal alveolar thickness decreased. The labial cortex showed a wider range of modeling area with a larger bending height and a smaller bending angle than the palatal side. The extent of inner remodeling was more prominent than the outer surface on both the labial and palatal sides. Conclusions Adaptive alveolar surface modeling occurred in response to incisor tipping retraction on both the lingual and labial sides although these changes occurred in an uncoordinated manner. Tipping retraction of the maxillary incisors led to a reduction in alveolar volume.

Conventional radiography is the mainstay for evaluation of developmental and pathologic disorders of oral and maxillofacial structures. Occasionally, clinicians may experience diagnostic pitfalls during interpretation of these imaging modalities. The aim of this article is to present 4 cases of pseudopathologic disorders found on intraoral and panoramic radiographs. Subsequent use of cone beam computed tomographic (CBCT) imaging determined that the initial concerning findings represented anatomical or radiographic anomalies rather than pathologic processes. Supplemental use of CBCT scans may enhance diagnostic assessment, possibly reducing the need for surgical intervention, and elucidate structurally compromised regions of the jaw that could predispose it to fracture. [ABSTRACT FROM AUTHOR]

The primary goals of this study were to identify the influence of temperature and drying time on pretreated cassava flour, as well as the optimal settings for the factors and to analyze the microstructure of cassava flour. The experiment was designed using the response surface methodology with central composite design and the superimposition approach in order to assess the effect of drying temperature (45.85–74.14 °C) and drying time (3.96–11.03 h) and the optimal drying conditions of the cassava flour investigated. Soaking and blanching were applied as pretreatments to freshly sliced cassava tubers. The value moisture content of cassava flour was between 6.22% and 11.07%, whereas the observed whiteness index in cassava flour ranged from 72.62 to 92.67 in all pretreated cassava flour samples. Through analysis of variance, each drying factor, their interaction, and all squared terms had a substantial impact on moisture content and whiteness index. The optimized values for drying temperature and drying time for each pretreated cassava flour were 70 °C and 10 h, respectively. The microstructure showed a non-gelatinized, relatively homogeneous in size and shape sample with pretreatment soaked in distilled water at room temperature. These study results are relevant to the development of more sustainable cassava flour production. [ABSTRACT FROM AUTHOR]

Background: The purpose of this study was to assess morphological changes of the upper anterior alveolus after retraction of a maxillary incisor by applying three-dimensional (3D) superimposition of pretreatment (T1) and posttreatment (T2) cone-beam computed tomography (CBCT) data. Methods: The study group was comprised of 28 patients with skeletal Class II malocclusion who underwent incisor retraction. CBCT data were acquired before (T1) and after (T2) orthodontic treatment. Labial and palatal alveolar thickness were assessed at the crestal, midroot and apical levels of the retracted incisors. Following three-dimensional (3D) cranial base superimposition, we performed surface modeling and inner remodeling of the labial and palatal alveolar cortex of the maxillary incisors. Paired t-tests were used to compare T0 and T1 bone thickness and volume measurements. Comparisons between labial and palatal surface modeling, inner remodeling and outer surface modeling were performed with paired t-tests in SPSS 20.0 version. Results: We observed controlled tipping retraction of the upper incisor. After treatment, the alveolar thickness on the labial sides increased and the palatal alveolar thickness decreased. The labial cortex showed a wider range of modeling area with a larger bending height and a smaller bending angle than the palatal side. The extent of inner remodeling was more prominent than the outer surface on both the labial and palatal sides. Conclusions: Adaptive alveolar surface modeling occurred in response to incisor tipping retraction on both the lingual and labial sides although these changes occurred in an uncoordinated manner. Tipping retraction of the maxillary incisors led to a reduction in alveolar volume. [ABSTRACT FROM AUTHOR]

Redd counts are commonly applied to estimate spawning population size for salmonids and allow for broad spatial and temporal coverage in monitoring efforts. However, the utility of redd counts may be compromised by observation error, particularly with respect to superimposition, where later arriving spawners construct redds overlapping existing redds. Here, we provide a mechanistic evaluation of the effects of superimposition on the error structure and biological significance of redd count data for Yellowstone cutthroat trout (Oncorhynchus clarkii bouvieri) spawning within tributaries to the Snake River, Wyoming. We used a Bayesian framework to parse observation error into distinct components and found low detection of redd clusters (i.e., areas of superimposition) was offset by overestimates of the number of redds per cluster, such that observed counts accurately reflected census redd abundance. However, a saturating relationship between redd counts and spawner abundance indicated that counts is best interpreted as effective reproductive effort rather than spawner abundance. Our results provide a mechanistic understanding of redd count data that can be used to assess their application and interpretation for monitoring. [ABSTRACT FROM AUTHOR]

Objectives: To develop and validate a method for accurate quantitative assessment of gingival recessions based on superimposition of serial 3D digital models. Materials and methods: Gingival recessions of mild (0.5–2 mm) and increased (3–7 mm) severity were simulated on stone casts and surface models were created. The outlines of the gingival margins of the mild (A) and severe recessions (B) were compared to the original gingival margins following 3D best fit superimposition through a gold standard technique (GS), which used intact adjacent structures, and the tested method (CC), which used single tooth crowns at the position of recessions, as superimposition reference. The primary outcome was the distance between the most apical point of each corresponding gingival margin along the respective tooth long axis. Results: For mild recessions, the median difference of the test methods (CC_A) from the reference method (GS_A) was 0.008 mm (IQR: 0.093; range: − 0.143, 0.147). For severe recessions, the median difference of the test method (CC_B) from the reference method (GS_B) was 0.009 mm (IQR: 0.091; range: − 0.170, 0.198). The proposed method (CC) showed very high intra- and inter-operator reproducibility (median: 0.025 and 0.033 mm, respectively). Conclusions: The suggested method offers highly accurate monitoring of gingival margin changes and diagnosis of gingival recessions using 3D digital dental models. The method is applicable irrespective of changes in tooth position or form, allowing for assessments over any time span. Clinical relevance: The accurate detection and visualization of gingival margin changes in 3D will enhance diagnosis and patient-doctor communication. [ABSTRACT FROM AUTHOR]

While online shopping has become popular in recent years, certain problems related to customer expectations about the appearance and fitting of clothing items still need to be solved. Online customers looking for clothing products may be unsatisfied as they do not have the possibility to try on clothes and view how they would look on them. Additionally, vendors are burdened with the cost of items returned by unsatisfied customers. Augmented Reality (AR) can help vendors to attract more customers and enhance their shopping experience. Customers are more likely to be satisfied with their purchases when they can try the clothes on before purchasing them, which ultimately reduces the return costs for vendors. This paper presents an AR mobile application called Smart Fitting which was developed in order to allow online customers to try on clothing items by using 3D models virtually. The most recent AR development tools for iOS operating systems, including XCode and Unity, are utilized for creating the proposed mobile application. After an integration testing for the mobile application functions, seven target female consumers participated in the usability evaluation for this mobile application which was meant to prove its ease of use and evaluate the customers’ satisfaction. The obtained results showed that Smart Fitting can improve the users shopping experience by providing a more realistic clothes visualization than the traditional online shopping interfaces. [ABSTRACT FROM AUTHOR]

This articles examines the 2022 choreographic work "100 Years of Cinematic Solitude in 300 Moving Pieces" by Canadian choreographer Jonathan Osborn and queries the degree to which superimposition - the placement of one thing over another, typically so that both are still evident – can go beneath the surface to challenge tacit understandings of that which is skin-deep. [ABSTRACT FROM AUTHOR]

To evaluate the axial and dimensional changes of the condylar head after orthognathic surgery, including Le Fort I and bilateral sagittal split ramus osteotomies, and to assess condylar remodeling through three-dimensional (3D) surface superimposition. Twenty-four patients (15 females, 9 males; mean age: 32.22 ± 6.92 years) with skeletal Class III deformity were included in the study. Cone-beam computed tomography data obtained in the preoperative (T0) and postoperative (T1) periods were examined using Mimics and 3-Matic software. The height, depth, and width of the condylar head and its angular changes were measured. The volumes of the 3D reconstructed models were calculated, and remodeling amounts were evaluated through regional surface superimposition. Statistical significance was set at P <.05. Following the surgery, there was a significant decrease in the size of condyles (P <.05). An inward rotation of the condyles was found in the axial plane (T0: 79.60 ± 6.01°, T1: 76.6 ± 6.48°, P <.05). The maximum resorption, maximum apposition, mean remodeling, and mean absolute remodeling were −2.63 ± 1.23 mm, 1.15 ± 0.4 mm, −0.30 ± 0.34 mm, and 0.73 ± 0.43 mm, respectively. No correlation was found between the angular changes and remodeling parameters or linear and volumetric changes of the condylar head (P >.05). Condyles undergo a remodeling process with a resorptive character following orthognathic surgery, without clinically significant effects in the present study. [ABSTRACT FROM AUTHOR]

During the Victorian age, post-mortem and spirit photography became increasingly popular so that those who had lost dear people were offered an extended mourning ground. These types of images were produced in great number in order to prove the existence of the other world. It is natural that many of these dead people portraits deal with transparency, blur and diffusion, as the result of superimposing reality and spectrality. Later on, ectoplasms were caught on photosensitive materials by a great number of spirit hunters, aiming at the same purpose of demonstrating the physicality of the invisible order. Cinema imported the spiritualist themes and the subjects related to them and continued the same tradition of revealing to the common eye of the spectator a supernatural realm. Our paper analyses the aesthetics of different styles and techniques of working with these delicate subjects in photography and film throughout the ages, from Mumler to Méliès. [ABSTRACT FROM AUTHOR]

Studies on negation in the school of Vyākaraṇa have focused on the early period of its development, especially on the interpretation of prasajya and paryudāsa types of negation provided by early commentators starting with Patañjali and elaborated on by Bhartṛhari. The post-Bhartṛhari period requires thorough research when it comes to the theory of meaning and cognition proposed by Indian grammarians. The present article analyses the interpretation of negation proposed by Kauṇḍabhaṭṭa in the Vaiyākaraṇabhūṣaṇasāra and shows it against the background of theory of negation that had been developing for centuries within the school of Vyākaraṇa. [ABSTRACT FROM AUTHOR]

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Purpose: To evaluate the effect of different 3D printing orientations on internal and seating accuracy of implant surgical templates fabricated by a digital light processing (DLP) printer. Materials and methods: A single maxillary model with a missing central incisor was used to design a surgical template for single implant placement. According to the printing orientation, three surgical template groups were included in the study: horizontal (H), angled (A) and vertical (V) (n = 10). For the H group, the templates were produced parallel to the printing platform, while for the V group, the templates were perpendicular to the platform. The A group templates had a 45° angle orientation to the platform. Each template was scanned at the fitting surface and after seating on the master model. The internal accuracy involved measuring the trueness and precision of the internal surface, while for the seating accuracy, the vertical discrepancy after seating the template was measured. To determine the difference among the groups, ANOVA test was applied followed by Tukey post hoc tests (α = 0.05). Results: The H group had the lowest internal surface inaccuracy (trueness = 100.7 μm; precision = 69.1 μm) followed by A (trueness = 114.0 μm; precision = 77.3 μm) and V (trueness = 120.3 μm; precision = 82.4 μm) groups, respectively (p < 0.001). Similarly, the H group had the most superior seating accuracy (543.8 μm) followed by A group (1006.0 μm) and V group (1278.0 μm), respectively (p < 0.001). Conclusions: The orientation of 3D printing of implant surgical templates fabricated by the DLP desktop printer influenced the accuracy of the templates. The horizontally printed templates consistently exhibited superior accuracy. To reduce deviation of implant placement, it is recommended to print the surgical templates with their largest dimension parallel to the printing platform. [ABSTRACT FROM AUTHOR]

The superimposition of sequential radiographs of the head is commonly used to determine the amount and direction of orthodontic tooth movement. A harmless method includes the timely unlimited superimposition on the relatively stable palatal rugae, but the method is performed manually and, if automated, relies on the best fit of surfaces, not only rugal structures. In the first step, motion estimation requires segmenting and detecting the location of teeth and rugae at any time during the orthodontic intervention. Aim: to develop a process of tooth segmentation that eliminates all manual steps to achieve an autonomous system of assessment of the dentition. Methods: A dataset of 797 occlusal views from photographs of teeth was created. The photographs were manually semantically segmented and labeled. Machine learning methods were applied to identify a robust deep network architecture able to semantically segment teeth in unseen photographs. Using well-defined metrics such as accuracy, precision, and the average mean intersection over union (mIoU), four network architectures were tested: MobileUnet, AdapNet, DenseNet, and SegNet. The robustness of the trained network was additionally tested on a set of 47 image pairs of patients before and after orthodontic treatment. Results: SegNet was the most accurate network, producing 95.19% accuracy and an average mIoU value of 86.66% for the main sample and 86.2% for pre- and post-treatment images. Conclusions: Four architectural tests were developed for automated individual teeth segmentation and detection in two-dimensional photos that required no post-processing. Accuracy and robustness were best achieved with SegNet. Further research should focus on clinical applications and 3D system development. [ABSTRACT FROM AUTHOR]

We performed this clinical study in order to evaluate the reliability of the Guided Bone Regeneration (GBR) surgical technique through the use of customized CAD CAM titanium meshes (Yxoss CBR® Reoss) in order to show an alternative method of bone augmentation. Materials and methods: Nine patients presenting 10 bone defects were referred to solve oral dysfunction due to edentulous atrophic ridges. Guided bone regeneration was performed with titanium meshes combined with autogenous bone grafting and heterologous bovine bone mineral grafting, and exclusively a "poncho technique" soft tissue approach for all the cases. After a mean 9 months of graft healing (range 6–12 months), titanium meshes were removed, and implant surgery was subsequently performed. The results we obtained were positive in terms of volumetric increases in height, length and thickness of the atrophic ridges without biological complications detectable before implant surgery. Results: Out of nine, one site met titanium mesh exposure: however, in all 10 sites a three-dimensional volumetric bone implementation was obtained. The statistical results were estimated by uploading and superimposing cbct scans before and after CBR surgery for each patient, so it was possible evaluate the maximum linear vertical and horizontal bone gain through dedicated Cad Cam software (Exocad GmbH®). The average horizontal gain was 6.37 ± 2.17 mm (range 2.78–9.12 mm) and vertical gain was 5.95 ± 2.06 mm (range 2.68–9.02 mm). A total of 18 implants were placed into the grafted sites with a 100% survival rate (clearly they are relative percentages to be compared to the short time elapsed). Conclusions: The results we obtained in this study suggest that this CBR procedure (Yxoss® by Reoss) is reliable and safe for bone regeneration to allow implant-prosthetic restoration in horizontal, vertical and combined bone defects. The soft tissue management is diriment: all the cases were managed with a "poncho" flap approach to decrease exposure complication. [ABSTRACT FROM AUTHOR]

Objectives: To measure the impact of the superimposition methods on accuracy analyses in digital implant research using an ISO-recommended 3-dimensional (3D) metrology-grade inspection software., Materials and Methods: A six-implant edentulous maxillary model was scanned using a desktop scanner (7Series; DentalWings; Montreal, Canada) and an intraoral scanner (TRIOS 4; 3Shape; Copenhagen, Denmark) to generate a reference and an experimental mesh, respectively. Thirty experimental standard tesselletion language (STL) files were superimposed onto the reference model's STL using the core features of six superimposition methods, creating the following groups: initial automated pre-alignment (GI), landmark-based alignment (G1), partial area-based alignment (G2), entire area-based alignment (G3), and double alignment combining landmark-based alignment with entire model area-based alignment (G4 ) or the scan bodies' surface (G5). The groups underwent various alignment variations, resulting in sixteen subgroups (n = 30). The alignment accuracy between experimental and reference meshes was quantified by using the root mean square (RMS) error as trueness and its fluctuation as precision. The Kruskal-Wallis test with a subsequent adjusted post-hoc Dunn's pairwise comparison test was used to analyze the data (α = 0.05). The reliability of the measurements was assessed using the intraclass correlation coefficient (ICC)., Results: A total of 480 superimpositions were performed. No significant differences were found in trueness and precision among the groups (p > 0.05), except for partial area-based alignment (p < 0.001). Subgroup analysis showed significant differences for partial area-based alignment considering only one scan body (p < 0.001). Initial automated alignment was as accurate as landmark-based, partial, or entire area-based alignments (p > 0.05). Double alignments did not improve alignment accuracy (p > 0.05). The entire area-based alignment of the scan bodies' surface had the least effect on accuracy analyses., Conclusions: Digital oral implant investigation remains unaffected by the superimposition method when ISO-recommended 3D metrology-grade inspection software is used. At least two scan bodies are needed when considering partial area-based alignments., Clinical Significance: The superimposition method choice within the tested ISO-recommended 3D inspection software did not impact accuracy analyses in digital implant investigation., Competing Interests: Declaration of competing interest The authors have no conflict of interest to report pertaining to the conduction of this study., (Copyright © 2024. Published by Elsevier Ltd.)

The primary goals of this study were to identify the influence of temperature and drying time on pretreated cassava flour, as well as the optimal settings for the factors and to analyze the microstructure of cassava flour. The experiment was designed using the response surface methodology with central composite design and the superimposition approach in order to assess the effect of drying temperature (45.85–74.14 °C) and drying time (3.96–11.03 h) and the optimal drying conditions of the cassava flour investigated. Soaking and blanching were applied as pretreatments to freshly sliced cassava tubers. The value moisture content of cassava flour was between 6.22% and 11.07%, whereas the observed whiteness index in cassava flour ranged from 72.62 to 92.67 in all pretreated cassava flour samples. Through analysis of variance, each drying factor, their interaction, and all squared terms had a substantial impact on moisture content and whiteness index. The optimized values for drying temperature and drying time for each pretreated cassava flour were 70 °C and 10 h, respectively. The microstructure showed a non-gelatinized, relatively homogeneous in size and shape sample with pretreatment soaked in distilled water at room temperature. These study results are relevant to the development of more sustainable cassava flour production.

Objective: This study aimed to quantitatively evaluate the effect of implant‐supported provisional restorations (ISPRs) on the accuracy of the intraoral scanned peri‐implant soft‐tissue profile in the esthetic area. Materials and Methods: Sixteen patients with a single ISPR in the maxillary central incisor's region were recruited for this study. Three impression methods were sequentially used in each patient: (1) an intraoral scanning (IOS) with the ISPR, (2) a conventional impression using the ISPR as impression coping, and (3) a routine IOS without the ISPR. The stereolithography files of the three impression methods obtained from the same patient were superimposed, and the conventional impression method was used as the reference model. Two‐dimensional (2D) and three‐dimensional (3D) analyses were performed to measure the peri‐implant soft‐tissue deviation between the reference models and IOS from the groups with or without the ISPR, respectively. Data were presented as the means ± standard deviations. Two‐way analyses of variance with post hoc Sidak's multiple comparisons and paired t‐tests were performed for 2D and 3D analyses, respectively. The significance level was set at p <.05. Results: The peri‐implant mucosa without the ISPR immediately collapsed (<20 s), particularly on the palatine side of the labial mucosa and labial side of the palatine mucosa. Consequently, the IOS without the ISPR led to 414.7 ± 116.0 μm of overall dimensional deformation in the cuff‐like submucosal region, which was significantly larger (p <.0001) than that in the IOS with the ISPR (230.6 ± 85.5 μm). Conclusion: Implant‐supported provisional restorations are important for accurate replication of the intraorally scanned peri‐implant soft‐tissue profile. [ABSTRACT FROM AUTHOR]

It is shown that a gold-plated device mounted on a tenor saxophone, forming a small bridge between the mouthpiece and the S-bow, can change two characteristics of the radiated sound: (1) the radiated acoustic energy of the harmonics with emission maxima around 1500–3000 Hz, which is slightly reduced for tones played in the lower register of the saxophone; (2) the frequency jitter of all tones in the regular and upper register of the saxophone show a two-fold increase. Through simulated phase-shifted superimpositions of the recorded waves, it is shown that the cancellation of acoustic energy due to antiphase superimposition is significantly reduced in recordings with the bridge. Simulations with artificially generated acoustic waves confirm that acoustic waves with a certain systematic jitter show less cancelling of the acoustic energy under a phase-shifted superimposition, compared to acoustic waves with no frequency jitter; thus, being beneficial for live performances in small halls with minimal acoustic optimization. The data further indicate that the occasionally hearable “rumble” of a wind instrument orchestra with instruments showing slight differences in the frequency of the harmonics might be reduced (or avoided), if the radiated acoustic waves have a systematic jitter of a certain magnitude.

Aim: To introduce and validate a computer‐aided method for direct measurements and visualization of gingival margin (GM) changes. Materials and Methods: The method consists of five main steps: digital model acquisition, superimposition, computer‐aided GM detection, distance calculation between the GM curves, and visualization. The precision of the method was evaluated with repeatability and reproducibility analysis (n = 78 teeth). The method's repeatability was evaluated by repeating the algorithm on the same digital models by two operators. The reproducibility was evaluated by repeating the algorithm on two consecutive digital models obtained with a scan−rescan process at the same time point on the same patient. For demonstration, the proposed method for direct measurements of GM changes was performed on patients who had undergone root coverage procedures and treatment of periodontal disease. Results: Excellent repeatability was found for both intra‐ and inter‐operator variability, that is, 0.00 mm, regarding computer‐aided GM detection. The reproducibility of computer‐aided GM detection evaluated on scan−rescan models was 0.10 mm. Conclusions: The presented method enables the evaluation of GM changes in a simple, precise, and comprehensive manner through non‐invasive acquisition and superimposition of digital models. [ABSTRACT FROM AUTHOR]