Search

Objectives: To evaluate recent advances in the automatic multimodal registration of cone-beam computed tomography (CBCT) and intraoral scans (IOS) and their clinical significance in dentistry. Methods: A comprehensive literature search was conducted in October 2024 across the PubMed, Web of Science, and IEEE Xplore databases, including studies that were published in the past decade. The inclusion criteria were as follows: English-language studies, randomized and nonrandomized controlled trials, cohort studies, case–control studies, cross-sectional studies, and retrospective studies. Results: Of the 493 articles identified, 22 met the inclusion criteria. Among these, 14 studies used geometry-based methods, 7 used artificial intelligence (AI) techniques, and 1 compared the accuracy of both approaches. Geometry-based methods primarily utilize two-stage coarse-to-fine registration algorithms, which require relatively fewer computational resources. In contrast, AI methods leverage advanced deep learning models, achieving significant improvements in automation and robustness. Conclusions: Recent advances in CBCT and IOS registration technologies have considerably increased the efficiency and accuracy of 3D dental modelling, and these technologies show promise for application in orthodontics, implantology, and oral surgery. Geometry-based algorithms deliver reliable performance with low computational demand, whereas AI-driven approaches demonstrate significant potential for achieving fully automated and highly accurate registration. Future research should focus on challenges such as unstable registration landmarks or limited dataset diversity, to ensure their stability in complex clinical scenarios. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to compare the accuracy of digital complete‐arch implant impressions with prefabricated aids using three intraoral scanners (IOSs) and explore the correlation between virtual deviation measurement and physical framework misfit. Materials and Methods: Four edentulous maxillary master models with four and six parallel and angular implants were fabricated and scanned by a laboratory scanner as reference scans. Ten scans of each master model were acquired using three IOSs (IOS‐T, IOS‐M, and IOS‐A) with and without prefabricated aids. Trueness and precision of root mean square (RMS) errors were measured. Ten aluminum alloy frameworks were fabricated, and the misfit was measured with a micro‐computed tomography scan with one screw tightened. Results: Trueness and precision showed significant improvement when prefabricated aids were used for all three IOSs (p < 0.010). Median (interquartile range) RMS errors of trueness reduced from 67.5 (30.4) to 61.8 (30.3) μm, from 100.6 (35.4) to 45.9 (15.1) μm, and from 52.7 (33.2) to 41.1 (22.5) μm for scanner IOS‐T, IOS‐M, and IOS‐A, respectively (p < 0.010). The precision of IOS‐A and IOS‐M was significantly better than IOS‐T when using prefabricated aid (p < 0.001). RMS errors and the maximum marginal misfit of the framework were significantly correlated (p < 0.001, R2 = 0.845). Conclusions: With the prefabricated aids, the accuracy of IOSs enhanced significantly in digital complete‐arch implant impressions. Three IOSs showed different levels of improvement in accuracy. Virtual RMS errors <62.2 μm could be the clinically acceptable threshold (150 μm) for framework passive fit. [ABSTRACT FROM AUTHOR]

Objectives: The purpose of this clinical study is to compare implant full-arch intraoral scans taken immediately after implant placement with those obtained after tissue healing in patients rehabilitated with implant-supported fixed prostheses. Methods: Between September 2023 and March 2024, a total of 19 patients with compromised residual dentition (6 women; 13 men) were rehabilitated using 4-to-6 immediately loaded post-extraction implants. These implants supported fixed full-arch screw-retained prostheses either in the lower jaw (9 patients) or upper jaw (10 patients). Intraoral scans were taken immediately after implant placement (termed "immediate scan"). After a healing period of four months, the provisional prosthesis was removed, and a second intraoral scan was performed using the same scan bodies and scan pattern as the initial scan (termed "delayed scan"). The two scans were overlaid, and the discrepancies between them were measured. Results: The average discrepancy between the immediate and delayed scans was 0.1905 mm. Our statistical analysis revealed larger discrepancies for implants placed in the posterior areas, with the implant in site 1.6 (Implant 1) showing a discrepancy of 0.2326 mm, and the implant in site 2.6 (Implant 4) showing a discrepancy of 0.2124 mm (p = 0.05). No statistically significant difference was observed when comparing patients treated in the upper and lower jaws. Conclusions: Within the limitations of the study and based on this result, clinicians should be aware that an immediate post-surgical intraoral digital scan for implant-supported full-arch rehabilitations may result in a higher risk of imprecision. Furthermore, according to the results of the study, the accuracy of the digital impression on implant full-arch rehabilitations seems to be influenced by the clinician's skills. Further studies with larger sample sizes are required to confirm our results. [ABSTRACT FROM AUTHOR]

Restoring deep, extensive carious lesions and subgingival situations can be challenging due to difficulties in placing matrices and achieving isolation. This article describes a technique utilizing individually designed digital matrices for challenging cases, offering an alternative solution aiding the reconstruction of the missing dental structures. Three cases are presented with difficult subgingival cavities or severe destruction of dental hard tissues, where a custom-made matrix was used to bridge the challenges of matrix placement and isolation. Digital impressions of dental arches were taken, and custom-made metal instruments were manufactured through computer-aided design and subsequent sintering. These instruments aided the elevation of deep margins and the reconstruction of the teeth. The presented technique yielded favorable results in terms of accuracy and feasibility for these challenging cases. However, it should be noted that the procedure requires additional time and incurs costs for the necessary elements. [ABSTRACT FROM AUTHOR]

Abstract Introduction This study aims to compare sagittal condylar inclination (SCI) measurements derived from three workflows: intraoral scan (IOS) aligned with cone-beam computed tomography (CBCT), IOS aligned with facial scan (FS), and a jaw motion analyzer (JMA) system, in a cohort of young individuals with established normal occlusion. Additionally, the study aims to identify sources contributing to variance in these measurement approaches. Methods Twenty-four healthy individuals exhibiting normal occlusion were enrolled in this clinical trial. The SCI was delineated using a virtual articulator (VA) by aligning IOS with both CBCT and FS, creating two distinct workflows labeled CBCT-IOS and FS-IOS, respectively. Concurrently, SCI measurements were also acquired using a JMA. The normality of data distribution for the difference in bilateral SCI measurements within each workflow was tested using the Shapiro-Wilk test. Depending on the outcomes of this test, we utilized either a paired-sample T-test or Wilcoxon test for bilateral SCI comparisons. The inter-workflow differences were assessed using the Kruskal-Wallis H test. Bland-Altman plots were assess the interchangeability and consistency across each pair of digital methods and to evaluate the aggregate consistency among the trio of digital approaches. Results The analysis revealed that the CBCT-IOS workflow yielded the lowest average SCI measurements, whereas the JMA workflow produced the highest values. No significant differences were found in the SCI measurements between the left and right sides obtained by CBCT-IOS and JMA (P > .05), with the exception of the FS-IOS workflow (P = .002). Additionally, inter-flow comparisons revealed no significant differences in SCI measurements (P > .05), except when contrasting the SCI as measured by CBCT-IOS and JMA (P = .0131). The Bland-Altman plots demonstrated a high degree of consistency and 95% limits of agreement across the three digital workflows. Conclusion SCI measurements obtained from the three digital workflows exhibit a high degree of consistency and are interchangeable, affirming their clinical applicability for precise SCI assessment in young individuals with normal occlusion.

Abstract Background Peri-implant soft tissue corrections are often indicated following alveolar ridge augmentation, due to the distortion of the keratinized mucosa at the area of augmentation. The objective of the current study was to evaluate the dimensional soft tissue changes following horizontal guided bone regeneration (GBR) utilizing 3D digital data. Methods 8 mandibular surgical sites with horizontal alveolar ridge deficiencies were treated utilizing a resorbable collagen membrane and a split-thickness flap design. Baseline and 6-month follow-up cone-beam computed tomography (CBCT) scans were reconstructed as 3D virtual models and were superimposed with the corresponding intraoral scan. Linear changes of supracrestal vertical- horizontal soft tissue alterations were measured in relation to the alveolar crest at the mesial- middle- and distal aspect of the surgical area. Soft tissue dimensions were measured at baseline and at 6-month follow-up. Results Preoperative supracrestal soft tissue height measured midcrestally averaged at 2.37 mm ± 0.68 mm, 2.37 mm ± 0.71 mm and 2.64 mm ± 0.87 mm at the mesial-, middle- and distal planes. Whereas postoperative supracrestal soft tissue height was measured at 2.62 mm ± 0.72 mm, 2.67 mm ± 0.67 mm and 3.69 mm ± 1.02 mm at the mesial, middle and distal planes, respectively. Supracrestal soft tissue width changed from 2.14 mm ± 0.72 mm to 2.47 mm ± 0.46 mm at the mesial, from 1.72 mm ± 0.44 mm to 2.07 mm ± 0.67 mm and from 2.15 mm ± 0.36 mm to 2.36 mm ± 0.59 mm at the mesial, middle and distal planes, respectively. Additionally the buccal horizontal displacement of supracrestal soft tissues could be observed. Conclusions The current study did not report significant supracrestal soft tissue reduction following horizontal GBR with a split-thickness flap. Even though there was a slight increase in both vertical and horizontal dimensions, differences are clinically negligible. Trail registration The trail was approved by the U.S. National Library of Medicine ( www.clinicaltrials.gov ); trial registration number: NCT05538715; registration date: 09/09/2022.

Nowadays, digital technologies represent an essential tool for dentists and dental technicians, and the backbone of the communication between them. Aim of the study is to analyze the application of digital technologies in a common dental office and in transferring information to the dental lab. Materials and methods. The retrospective study included patients who presented for treatment to the dentist, in a 12 months period of time. Searched databases included dental charts, radiologic and imagistic data (OPG, CBCT), clinical photos and digital dental impressions. A comparison was made between the used digital tools as frequency. Results: 580 patients were included, 275 men and 305 women, aged between 19 and 82. Digital technologies used in the dental office in the studied period were: OPG (100%), CBCT examinations (25,34%), digital photographic exams (38,10%), intraoral scanning (24,13%), digital intraoral impressions (19,65%). Conclusions: All patients who attended the dental office during the study period received an OPG examination, while significant fewer patients were investigated using other digital technologies. For an easier, faster and complete data transfer between dental office and dental lab, digital evaluation is mandatory.

Introduction: This study aims to compare sagittal condylar inclination (SCI) measurements derived from three workflows: intraoral scan (IOS) aligned with cone-beam computed tomography (CBCT), IOS aligned with facial scan (FS), and a jaw motion analyzer (JMA) system, in a cohort of young individuals with established normal occlusion. Additionally, the study aims to identify sources contributing to variance in these measurement approaches. Methods: Twenty-four healthy individuals exhibiting normal occlusion were enrolled in this clinical trial. The SCI was delineated using a virtual articulator (VA) by aligning IOS with both CBCT and FS, creating two distinct workflows labeled CBCT-IOS and FS-IOS, respectively. Concurrently, SCI measurements were also acquired using a JMA. The normality of data distribution for the difference in bilateral SCI measurements within each workflow was tested using the Shapiro-Wilk test. Depending on the outcomes of this test, we utilized either a paired-sample T-test or Wilcoxon test for bilateral SCI comparisons. The inter-workflow differences were assessed using the Kruskal-Wallis H test. Bland-Altman plots were assess the interchangeability and consistency across each pair of digital methods and to evaluate the aggregate consistency among the trio of digital approaches. Results: The analysis revealed that the CBCT-IOS workflow yielded the lowest average SCI measurements, whereas the JMA workflow produced the highest values. No significant differences were found in the SCI measurements between the left and right sides obtained by CBCT-IOS and JMA (P >.05), with the exception of the FS-IOS workflow (P =.002). Additionally, inter-flow comparisons revealed no significant differences in SCI measurements (P >.05), except when contrasting the SCI as measured by CBCT-IOS and JMA (P =.0131). The Bland-Altman plots demonstrated a high degree of consistency and 95% limits of agreement across the three digital workflows. Conclusion: SCI measurements obtained from the three digital workflows exhibit a high degree of consistency and are interchangeable, affirming their clinical applicability for precise SCI assessment in young individuals with normal occlusion. [ABSTRACT FROM AUTHOR]

Background: Although intraoral scanning is highly reliable, little is known about its accuracy in young children with limited mouth‐opening ability. Aim: To determine the accuracy of intraoral scans based on the degree of mouth opening. Design: To simulate mouth opening in children with primary dentition, three groups (n = 5 per group) were allocated by maximum mouth opening of 30, 37 and 40 mm. After the primary dentition model was connected to a dental phantom, intraoral scanning was performed using iTero and TRIOS4. The scanned files were digitally evaluated. Root mean square values were calculated to assess trueness and precision. Results: iTero showed deviations of three‐dimensional trueness of 0.067 ± 0.008, 0.063 ± 0.001 and 0.065 ± 0.005 mm, and TRIOS4 of 0.07 ± 0.002, 0.064 ± 0.003 and 0.066 ± 0.002 mm in the 30, 37 and 40 mm groups, respectively. There were no significant differences in either mouth opening (p >.017) or the intraoral scanners (p >.05). The same statistical results were obtained for precision, with the exception of the 30 mm of mouth opening. Conclusions: Within the limits of this study, limited mouth opening hardly influenced the accuracy of intraoral scanning. [ABSTRACT FROM AUTHOR]

In esthetic prosthetic treatment, color, shape, texture of teeth, and harmony with the facial appearance are considered very important. The virtual patient is formed by integrating data from intraoral and facial scans and mandibular movement records, making fabricating more aesthetic and functional prostheses possible in digital dentistry. In this case report, the patient with the tilted occlusal plane and facial asymmetry was restored with an anterior maxillary implant and a tooth-supported fixed prosthesis using the virtual patient. By using a virtual patient, it was possible to communicate between the dentist and patient or the dental technician during the design process, and we report this case because the results showed satisfactory aesthetic and functional results after treatment. [ABSTRACT FROM AUTHOR]

Background: Peri-implant soft tissue corrections are often indicated following alveolar ridge augmentation, due to the distortion of the keratinized mucosa at the area of augmentation. The objective of the current study was to evaluate the dimensional soft tissue changes following horizontal guided bone regeneration (GBR) utilizing 3D digital data. Methods: 8 mandibular surgical sites with horizontal alveolar ridge deficiencies were treated utilizing a resorbable collagen membrane and a split-thickness flap design. Baseline and 6-month follow-up cone-beam computed tomography (CBCT) scans were reconstructed as 3D virtual models and were superimposed with the corresponding intraoral scan. Linear changes of supracrestal vertical- horizontal soft tissue alterations were measured in relation to the alveolar crest at the mesial- middle- and distal aspect of the surgical area. Soft tissue dimensions were measured at baseline and at 6-month follow-up. Results: Preoperative supracrestal soft tissue height measured midcrestally averaged at 2.37 mm ± 0.68 mm, 2.37 mm ± 0.71 mm and 2.64 mm ± 0.87 mm at the mesial-, middle- and distal planes. Whereas postoperative supracrestal soft tissue height was measured at 2.62 mm ± 0.72 mm, 2.67 mm ± 0.67 mm and 3.69 mm ± 1.02 mm at the mesial, middle and distal planes, respectively. Supracrestal soft tissue width changed from 2.14 mm ± 0.72 mm to 2.47 mm ± 0.46 mm at the mesial, from 1.72 mm ± 0.44 mm to 2.07 mm ± 0.67 mm and from 2.15 mm ± 0.36 mm to 2.36 mm ± 0.59 mm at the mesial, middle and distal planes, respectively. Additionally the buccal horizontal displacement of supracrestal soft tissues could be observed. Conclusions: The current study did not report significant supracrestal soft tissue reduction following horizontal GBR with a split-thickness flap. Even though there was a slight increase in both vertical and horizontal dimensions, differences are clinically negligible. Trail registration: The trail was approved by the U.S. National Library of Medicine (www.clinicaltrials.gov); trial registration number: NCT05538715; registration date: 09/09/2022. [ABSTRACT FROM AUTHOR]

Aim: To introduce an objective method to evaluate the accuracy of implant position assessment in partially edentulous patients by comparing different techniques (conventional impression, intraoral scan, CBCT) to a reference 3D model obtained with an industrial scanner, the latter mimicking the clinical situation. Materials and Methods: Twenty‐nine implants were placed in four human cadaver heads using a fully guided flapless protocol. Implant position was assessed using (a) a conventional impression, (b) an intraoral scan, and (c) CBCT and compared to an industrial scan. Three‐dimensional models of intraoral scan body and implant were registered to the arch models and the deviation at implant shoulder, apex, and the angle of deviation were compared to each other as well as to the reference model. Results: The three assessment techniques showed statistically significant deviations (p <.01) from the industrial scan, for all measurements, with no difference between the techniques. The maximum deviation at the implant shoulder was 0.16 mm. At the implant apex this increased to 0.38 mm. The intraoral scan deviated significantly more than the CBCT (0.12 mm, p <.01) and the conventional impression (0.10 mm, p =.02). The maximum implant angle deviation was 1.0°. The intraoral scan deviated more than the conventional impression (0.3°, p =.02). Conclusion: All assessment techniques deviated from the reference industrial scan, but the differences were relatively small. Intraoral scans were slightly less accurate than both conventional impressions and CBCT. Depending on the application, however, this inaccuracy may not be clinically relevant. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this clinical study was to compare the accuracy of intraoral scan system (IOS) with prefabricated aids and stereophotogrammetry (SPG) compared with open tray implant impression (OI) for complete‐arch implant‐supported fixed dental prostheses (CIFDP). Materials and methods: Patients needing CIFDP were enrolled in this study. OI, reference standard, IOS with prefabricated aids, and SPG were performed for each patient. Distance and angle deviations between all pairs of abutment analogs, root mean square (RMS) errors between the aligned test and reference model, and chairside time were measured. The effect of inter‐abutment distance, jaw (maxilla or mandible), number of implants, and arch length on deviations was analyzed. The mixed effect model was applied to analyze deviations and RMS errors. Results: Fifteen consecutive individuals (6 females and 9 males, 47–77 years old) with 22 arches (9 upper and 13 lower jaws) and 115 implants were included. There was no significant difference in distance deviation comparing SPG and IOS with OI (p >.05). IOS showed a significantly greater angle deviation and RMS errors than SPG (median 0.40° vs. 0.31°, 69 μm vs. 45 μm, p <.01). The inter‐abutment distance was negatively correlated with the accuracy of SPG and IOS (p <.05). The chairside time for IOS, SPG, and OI was 10.49 ± 3.50, 14.71 ± 2.86, and 20.20 ± 3.01 min, respectively (p <.01). Conclusions: The accuracy of SPG and IOS with prefabricated aids was comparable. IOS was the most efficient workflow. [ABSTRACT FROM AUTHOR]

Background: Postoperative resorption of hard and soft tissues occurs as a consequence of tooth extraction. The Benex®-Control extractor allows minimally invasive extraction of the tooth without causing pronounced iatrogenic trauma. The aim of this study was to verify whether the resorption of the tissues after extraction can be reduced by using the Benex® system compared to the conventional extraction method. Methods: Postoperative intraoral scans were superimposed after surgery (t0), after 7 days (t1), after 14 days (t2), after 30 days (t3), after 60 days (t4), and after 90 days (t5) within the two groups (study n = 14, control n = 16), and defined regions of interest (ROIs) (1–8) and volume changes were analyzed. In addition, the influence of gingival thickness and the thickness of the labial cortical plate was investigated. Results: The greatest decrease in volume was observed in both groups in ROI3, although there was no significant difference observed between the groups. In the presence of an adjacent tooth, there was less volume loss in the affected ROIs (1, 2 and 7, 8). The thickness of the gingiva and the bony lamella did not significantly influence the change in volume. Conclusions: Due to the small cohort, the results are limited, and the hypothesis is rejected. [ABSTRACT FROM AUTHOR]

Root canal obliteration is caused by hard tissue apposition and is often associated with teeth with a history of trauma, orthodontic movement, caries reaction, restorative procedures near the pulp chamber, and teeth of elderly patients. Preoperative planning of root canal treatment should be thorough and include an assessment of the patient's signs and symptoms in addition to the evaluation of complementary examinations. In a 27-year-old patient with dyschromia of the lower central incisor, a history of dental trauma, and a positive response to vertical percussion, an initial periapical radiograph was obtained that showed calcification of the canal and presence of a periapical lesion. The patient presented with pain on chewing, a positive response to palpation and a vertical percussion test. The diagnosis was symptomatic apical periodontitis. A cone-beam computed tomography scan was requested and a surface scan was performed to establish a static guide. The root canal was accessed in the middle third of the root and the canal was located using a minimally invasive approach. The root canal was treated conventionally. Results obtained showed the success of the treatment after a 3-year clinical and radiographic follow-up. Therefore, the use of an endodontic guide in cases of calcified canals significantly reduces the clinician's working time and offers a more predictable approach to the treatment of these pathologies. [ABSTRACT FROM AUTHOR]

Nowadays, digital technologies represent an essential tool for dentists and dental technicians, and the backbone of the communication between them. Aim of the study is to analyze the application of digital technologies in a common dental office and in transferring information to the dental lab. Materials and methods. The retrospective study included patients who presented for treatment to the dentist, in a 12 months period of time. Searched databases included dental charts, radiologic and imagistic data (OPG, CBCT), clinical photos and digital dental impressions. A comparison was made between the used digital tools as frequency. Results: 580 patients were included, 275 men and 305 women, aged between 19 and 82. Digital technologies used in the dental office in the studied period were: OPG (100%), CBCT examinations (25,34%), digital photographic exams (38,10%), intraoral scanning (24,13%), digital intraoral impressions (19,65%). Conclusions: All patients who attended the dental office during the study period received an OPG examination, while significant fewer patients were investigated using other digital technologies. For an easier, faster and complete data transfer between dental office and dental lab, digital evaluation is mandatory. [ABSTRACT FROM AUTHOR]

Abstract Background Postoperative cone-beam computed tomography (CBCT) examination is considered a reliable method for clinicians to assess the positions of implants. Nevertheless, CBCT has drawbacks involving radiation exposure and high costs. Moreover, the image quality can be affected by artifacts. Recently, some literature has mentioned a digital registration method (DRM) as an alternative to CBCT for evaluating implant positions. The aim of this clinical study was to verify the accuracy of the DRM compared to CBCT scans in postoperative implant positioning. Materials and methods A total of 36 patients who received anterior maxillary implants were included in this clinical study, involving a total of 48 implants. The study included 24 patients in the single implant group and 12 patients in the dual implant group. The postoperative three-dimensional (3D) positions of implants were obtained using both CBCT and DRM. The DRM included three main steps. Firstly, the postoperative 3D data of the dentition and intraoral scan body (ISB) was obtained through the intraoral scan (IOS). Secondly, a virtual model named registration unit which comprised an implant replica and a matching ISB was created with the help of a lab scanner and reverse engineering software. Thirdly, by superimposing the registration unit and IOS data, the postoperative position of the implant was determined. The accuracy of DRM was evaluated by calculating the Root Mean Square (RMS) values after superimposing the implant positions obtained from DRM with those from postoperative CBCT. The accuracy of DRM was compared between the single implant group and the dual implant group using independent sample t-tests. The superimposition deviations of CBCT and IOS were also evaluated. Results The overall mean RMS was 0.29 ± 0.05 mm. The mean RMS was 0.30 ± 0.03 mm in the single implant group and 0.29 ± 0.06 mm in the dual implant group, with no significant difference (p = 0.27). The overall registration accuracy of the IOS and CBCT data ranged from 0.14 ± 0.05 mm to 0.21 ± 0.08 mm. Conclusion In comparison with the 3D implant positions obtained by CBCT, the implant positions located by the DRM showed clinically acceptable deviation ranges. This method can be used in single and dual implant treatments to assess the implant positions.

Purpose: The increasing popularity of desktop 3D printers makes guided surgery more accessible. The aim of this in vitro study was to evaluate the accuracy of single-tooth guided implant surgery by means of a 3D-printed tooth-supported guide. Materials and Methods: Fifteen implants were virtually planned to replace a missing first mandibular molar, using planning software for guided implant surgery (Exoplan, Exocad). A tooth-supported guide was designed and manufactured using a desktop 3D printer (Asiga MAX UV). The implants were placed fully guided in resin casts, and a digital impression was taken to register their position. This scan was compared with the virtual implant position in the planning software, and the internal fit of the guides was evaluated using metrology software. One planning was executed six times for measuring precision. Results: For trueness, the mean angular deviation was 2.63 degrees (SD: 1.69 degrees; range: 0.38 to 5.99 degrees), the mean coronal deviation was 0.52 mm (SD: 0.25; range: 0.09 mm to 1.07 mm), and the mean apical deviation was 0.90 mm (SD: 0.47; range: 0.14 to 1.74 mm). The absolute apical mean deviation in the buccolingual direction (x-axis) was 0.70 mm (SD: 0.42, 0.12 to 1.65 mm; P < .001); in the mesiodistal direction (y-axis), it was 0.34 mm (SD: 0.26; range: 0.01 to 0.80 mm; P = .650); and in the vertical direction (z-axis), it was 0.32 mm (SD: 0.27; range: 0.02 to 1.00 mm; P = .010). The mean internal fit of the guides was 79.5 µm (SD: 19.6 µm; range: 51 to 118 µm). Conclusion: Desktop 3D-printed tooth-supported guides demonstrate an acceptable fit and acceptable level of accuracy for single implant placement. [ABSTRACT FROM AUTHOR]

Background: In this multicenter case series analysis, the authors present successful instances of 20 single-screw-retained and implant-supported prosthetic rehabilitation samples. Methods: A high-density heterologous dermal matrix (Derma® Osteobiol by Tecnoss, Torino, Italy) was employed with a specific technique named the matrix tissue graft (MTG) in all these cases characterized by an inadequate initial supra-crestal tissue height (thin if 1 mm or medium if 2 mm) to enhance the peri-implant soft tissues both vertically and horizontally. Results: The implants were deemed successful in all cases, yielding a success proportion of 100% (one-sided 97.5% confidence interval = 83.2–100%). The buccal and lingual gains were, respectively, 2.2 ± 0.38 mm (range 1.7–3.22 mm) and 0.83 ± 0.33 mm (range 0.1–1.5 mm). These measurements were calculated as the maximum distance between two superimposed.stl file models (derived from two different IOS devices) scanned before implant placement and 1 year after dermal matrix healing. Conclusions: An outstanding vertical and horizontal gain was obtained using this heterologous derma matrix placed above the bone crest and surrounding the dental implants. [ABSTRACT FROM AUTHOR]

Objective: The purpose of this article was to introduce a method for the digital application of three‐dimensional (3D) diagnosis and treatment with a virtual articulator and 3D data. Clinical Consideration: With the use of cone‐beam computed tomography (CBCT) and intraoral and facial scans, we can create a virtual articulator and evaluate the mandibular position in maximum intercuspation and centric‐related occlusion for the patient with an unstable occlusion and temporomandibular disorders (TMD). Based on this, we treated a case using a digital mandibular position indicator (MPI) and fabricated a stabilization splint using a 3D printer. This approach eliminates the traditional impression or model mounting process and the analog face bow transfer. Furthermore, the design of the stabilization splint is accomplished using software. Conclusions: The approach outlined in this article offers the potential for a digital diagnosis and treatment process by seamlessly integrating CBCT, intraoral scans, and facial scans with a high degree of accuracy. This may enhance precision in diagnosis and treatment planning, especially for patients with complicated TMD, in addition to facilitating effective communication with orthodontic patients who require thorough attention. Clinical Significance: Utilizing a virtual articulator and digital MPI for the occlusal evaluation of patients with TMD and unstable occlusion makes it possible to diagnose and analyze the occlusal condition accurately. This approach also allows for precision and efficiency in treatment. [ABSTRACT FROM AUTHOR]

Introduction: Cleft lip‐palate is the most common craniofacial congenital anomaly. Patients with Cleft lip palate require treatment with a multidisciplinary approach from birth to enable independent feeding and physiological growth. In the past, the fabrication of therapeutic devices for a child with a cleft lip palate was executed through conventional dental impression materials , with the risk of suffocation. The use of a digital workflow minimizes impression‐related risks and streamlines procedures. Methods: This study aims to propose a hybrid workflow that can combine the advantages of digital workflow with the advantages of analog workflow that can be applied daily by clinicians treating cleft lip‐palate‐affected patients. Results: The device created was immediately accepted by the patient allowing autonomous nutrition. Evaluation of the effectiveness of the device was done by body weight assessment every 15 days. Conclusion: The patient had growth comparable to that of a child born healthy. [ABSTRACT FROM AUTHOR]

Featured Application: This paper suggests that, in the case of a fixed retainer twist effect diagnosis, the retainer should be immediately removed, even if the patient is not keen on re-treatment in a short perspective.Background: One of the rarest complications of fixed orthodontic retention is inadvertent tooth movement of the teeth bonded to the retainer. A 25-year-old patient presented at the orthodontist as she was preoccupied about the position of the lower teeth. The aim of this case report was to present a follow-up of anterior teeth alignment after fixed retainer removal and to analyze the structure of the removed fixed orthodontic retainer in a patient suffering from a twist effect. Materials and Methods: The retainer that caused inadvertent movement has been removed, and subsequent teeth displacement was assessed with scan superimposition. The retainer structure and diameter were analyzed with a laser confocal microscope. Results: The superimposition showed significant improvements in the position of the teeth. The sole removal of the activated retainer resulted in a partial self-correction of the twist effect. Under microscopic observation, changes in the dimensions of the wire were found but were too small to cause significant changes in tooth position. Conclusions: A fixed retainer should always be removed when a twist effect is diagnosed. The wire sections covered with composite are less likely to untwist. In the presented case, the changes in the dimensions of the round retainer wire could not have led to changes in the teeth's positions. [ABSTRACT FROM AUTHOR]

Restoring deep, extensive carious lesions and subgingival situations can be challenging due to difficulties in placing matrices and achieving isolation. This article describes a technique utilizing individually designed digital matrices for challenging cases, offering an alternative solution aiding the reconstruction of the missing dental structures. Three cases are presented with difficult subgingival cavities or severe destruction of dental hard tissues, where a custom-made matrix was used to bridge the challenges of matrix placement and isolation. Digital impressions of dental arches were taken, and custom-made metal instruments were manufactured through computer-aided design and subsequent sintering. These instruments aided the elevation of deep margins and the reconstruction of the teeth. The presented technique yielded favorable results in terms of accuracy and feasibility for these challenging cases. However, it should be noted that the procedure requires additional time and incurs costs for the necessary elements.

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The human permanent dentition has been commonly used for personal identification due to its uniqueness. Limited research, however, is conducted using 3D digital dental models. We propose to develop a new 3D superimposition method using the contours of human dentition and to further evaluate its feasibility. A total of 270 intraoral scan models were collected from 135 subjects. After a one‐year interval, 52 subjects were chosen at random and the secondary intraoral scan models were obtained. The dentition contours of the first and secondary models were extracted to form a resource dataset and a test dataset. Through the application of the iterative nearest point (ICP) algorithm, the test dataset was registered with the resource dataset, and the root mean square error (RMSE) values of the point‐to‐point distances were calculated. 104 genuine pairs and 13,936 imposter pairs were generated, and in this study, the registration accuracy was 100%. The difference between mean RMSE values for the genuine pair (0.20 ± 0.06 mm) and the minimum RMSE value for the imposter pair (0.83 ± 0.06 mm) was significant in the maxillary arch (p < 0.05). Similarly, in the mandibular arch, the difference between mean RMSE values for the genuine pair (0.22 ± 0.07 mm) and the minimum RMSE value for the imposter pair (0.85 ± 0.08 mm) was significant (p < 0.05). The difference between the RMSE value for the genuine pair in the maxillary and the mandibular arch was significant (p < 0.05). This study indicated the feasibility of dentition contour‐based model superimposition and could be considered for personal identification in the future. [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]

To investigate the effect of implant angulation, non-free-end partial edentulism, and number of scan bodies on the accuracy of digital impressions of multiple implants in partially edentulous arches. Materials and Methods: Four reference models of partially edentulous mandibles with implants (RM1, RM2, RM3, and RM4) representing different intraoral situations were each scanned 10 times by an intraoral scanner. Reference scans were obtained by a laboratory scanner. Test scans were compared with reference scans to obtain the distance deviations (Δd) and angular deviations (Δθ) between scan bodies for trueness assessment. Differences among the repeated test scans of each model were measured and recorded as Δdp and Δθp for precision assessment. The Student t test (α = .05) was used to compare Δd, Δθ, Δdp, and Δθp of different reference models, including RM2 vs RM1 (effect of non-free-end partial edentulism), RM3 vs RM1 (effect of implant angulation), and RM4 vs RM1 (effect of number of scan bodies). Results: The implant with 17-degree angulation in RM3 showed significantly lower Δd, Δθ, and Δθp compared with the parallel implant in RM1 (Δd: P = .0382, Δθ: P = .0267, Δθp: P = .0417). The RM2 of non-free-end partial edentulism had lower distance and angular deviations than RM1, but without a significant difference. The number of scan bodies had no significant effect on the Δd, Δθ, Δdp, and Δθp of RM4 and RM1. Conclusion: Angulated implants showed better accuracy of digital impressions in partially edentulous arches compared with parallel implants. Non-free-end partial edentulism was attributed to improved accuracy, while the number of scan bodies showed no effect. [ABSTRACT FROM AUTHOR]

Background: Postoperative resorption of hard and soft tissues occurs as a consequence of tooth extraction. The Benex®-Control extractor allows minimally invasive extraction of the tooth without causing pronounced iatrogenic trauma. The aim of this study was to verify whether the resorption of the tissues after extraction can be reduced by using the Benex® system compared to the conventional extraction method. Methods: Postoperative intraoral scans were superimposed after surgery (t0), after 7 days (t1), after 14 days (t2), after 30 days (t3), after 60 days (t4), and after 90 days (t5) within the two groups (study n = 14, control n = 16), and defined regions of interest (ROIs) (1–8) and volume changes were analyzed. In addition, the influence of gingival thickness and the thickness of the labial cortical plate was investigated. Results: The greatest decrease in volume was observed in both groups in ROI3, although there was no significant difference observed between the groups. In the presence of an adjacent tooth, there was less volume loss in the affected ROIs (1, 2 and 7, 8). The thickness of the gingiva and the bony lamella did not significantly influence the change in volume. Conclusions: Due to the small cohort, the results are limited, and the hypothesis is rejected.

In contemporary practice, intraoral scans and cone-beam computed tomography (CBCT) are widely adopted techniques for tooth localization and the acquisition of comprehensive three-dimensional models. Despite their utility, each dataset presents inherent merits and limitations, prompting the pursuit of an amalgamated solution for optimization. Thus, this research introduces a novel 3D registration approach aimed at harmonizing these distinct datasets to offer a holistic perspective. In the pre-processing phase, a retrained Mask-RCNN is deployed on both sagittal and panoramic projections to partition upper and lower teeth from the encompassing CBCT raw data. Simultaneously, a chromatic classification model is proposed for segregating gingival tissue from tooth structures in intraoral scan data. Subsequently, the segregated datasets are aligned based on dental crowns, employing the robust RANSAC and ICP algorithms. To assess the proposed methodology's efficacy, the Euclidean distance between corresponding points is statistically evaluated. Additionally, dental experts, including two orthodontists and an experienced general dentist, evaluate the clinical potential by measuring distances between landmarks on tooth surfaces. The computed error in corresponding point distances between intraoral scan data and CBCT data in the automatically registered datasets utilizing the proposed technique is quantified at 0.234 ± 0.019 mm, which is significantly below the 0.3 mm CBCT voxel size. Moreover, the average measurement discrepancy among expert-identified landmarks ranges from 0.368 to 1.079 mm, underscoring the promise of the proposed method. [ABSTRACT FROM AUTHOR]

Objectives: To determine the effect of restoration artifact ('metal artifact') on registration accuracy of an intraoral scan and cone‐beam computed tomography (CBCT) scan, comparing fiducial marker‐based registration with markerless registration. Materials and methods: A maxillary model was fitted with multiple configurations of zirconia crowns to simulate various states of oral rehabilitation. Intraoral scans and CBCT scans (half and full rotation) were acquired. Registration was performed using markerless (point‐based registration with surface‐based refinement) and fiducial marker‐based registration. Each experimental condition was repeated 10 times (n = 320). The absolute deviation was measured at the canines and first molars, and the average and maximum values were analysed using multiple linear regression. Results: R2 was 0.874 for average error and 0.858 for maximum error. For markerless registration, there were 0.041 mm (p <.001) and 0.045 mm (p <.001) increases in average and maximum error per crown, respectively. For fiducial marker‐based registration, the effect of additional crowns was not statistically significant for average (p =.067) or maximum (p =.438) error. For a full arch of crowns, the regression model predicted average and maximum errors of 0.581 and 0.697 mm for the markerless technique, and 0.185 and 0.210 mm for the fiducial marker‐based technique. Overall, the fiducial marker‐based technique was more accurate for four or more crowns. The half rotation scan increased average error by 0.021 mm (p =.001) and maximum error by 0.029 mm (p <.001). Conclusions: Under the present study's experimental conditions, the fiducial marker‐based technique should be considered if four or more full‐coverage highly radiopaque restorations are present. [ABSTRACT FROM AUTHOR]

Digital workflows have become integral in orthodontic diagnosis and therapy, reducing risk factors and chair time with one-visit protocols. This study assessed the transfer accuracy of fully digital planned insertion guides for orthodontic mini-implants (OMIs) compared with freehanded insertion. Cone-beam computed tomography (CBCT) datasets and intraoral surface scans of 32 cadaver maxillae were used to place 64 miniscrews in the anterior palate. Three groups were formed, two using printed insertion guides (A and B) and one with freehand insertion (C). Group A used commercially available customized surgical templates and Group B in-house planned and fabricated insertion guides. Postoperative CBCT datasets were superimposed with the planning model, and accuracy measurements were performed using orthodontic software. Statistical differences were found for transverse angular deviations (4.81° in A vs. 12.66° in B and 5.02° in C, p = 0.003) and sagittal angular deviations (2.26° in A vs. 2.20° in B and 5.34° in C, p = 0.007). However, accurate insertion depth was not achieved in either guide group; Group A insertion was too shallow (−0.17 mm), whereas Group B insertion was deeper (+0.65 mm) than planned. Outsourcing the planning and fabrication of computer-aided design and computer-aided manufacturing insertion guides may be beneficial for certain indications; particularly, in this study, commercial templates demonstrated superior accuracy than our in-house–fabricated insertion guides. [ABSTRACT FROM AUTHOR]

Background and Objectives: With the increased trend towards digitalization in dentistry, intraoral scanning has, to a certain extent, replaced conventional impressions in particular clinical settings. Trueness and precision are essential traits for optical impressions but have so far been incompletely explored. Materials and Methods: We performed a study to evaluate the differences in the three-dimensional spatial orientations of implant analogs on a stone cast when using an intraoral scanner compared to a dental laboratory scanner. We assessed the deviation of the intraoral scans compared to the laboratory scan for three standardized implant measurement plans and compared these results with control scans of the neighboring natural teeth. Results: We found no statistically significant correlation between the measurements at the scan body level and the landmarks chosen as controls on the neighboring natural teeth (p = 0.198). The values for the implant scans presented wider variation compared to the control scans. The difference between the implant and the control planes ranged from −0.018 mm to +0.267 mm, with a median of −0.011 mm (IQR: −0.001–0.031 mm). While most values fell within a clinically acceptable margin of error of 0.05 mm, 12.5% of the measurements fell outside of this acceptable range and could potentially affect the quality of the resulting prosthetic work. Conclusions: For single-unit implant-supported restorations, intraoral scanning might have enough accuracy. However, the differences that result when scanning with an intraoral scanner may affect the quality of prosthetic work on multiple implants, especially if they are screw-retained. Based on our results, we propose different adaptations of the prosthetic protocol to minimize the potential effect of errors that may occur during the digital workflow. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to clarify the effect of occlusal force on appropriate optical interocclusal registration in clinical practice, considering periodontal ligament and jawbone deformation. Methods: Forty participants with natural, healthy dentition were enrolled (19 men and 21 women; mean age, 27.7 ± 2.0 years). A TRIOS3 intraoral scanner was used to scan the right lateral first premolar to the second molar areas of the upper and lower jaws. During scanning for interocclusal registration, participants were instructed to "bite normally," "bite lightly," and "bite strongly" to obtain data for the three occlusal patterns. The standard triangulated language (STL) data for each occlusion condition were superimposed using the appropriate software, following which the tooth displacement was calculated. The conventional method was also used to record the occlusal contact area for a silicone model using a dental contact analyzer. Results: Tooth displacement was significantly lower for the strong-bite condition than for the weak-bite condition (0.018 mm vs. 0.028 mm, P<0.05). As the occlusal force increased, the occlusal contact area also increased, and significant differences were observed among the different occlusal conditions (P<0.05). Conclusions: Occlusal contact area changed depending on the bite force when using the silicone impression or optical intraoral scanning methods. Moreover, using optical impression methods in "strong bite force" may reduce the deviation and allow for stable interocclusal registration. [ABSTRACT FROM AUTHOR]

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

The use of computerized optical impression making (COIM) for the fabrication of removable dentures for partially edentulous jaws is a rising trend in dental prosthetics. However, the accuracy of this method compared with that of traditional impression-making techniques remains uncertain. We therefore decided to evaluate the accuracy of COIM in the context of partially edentulous jaws in an in vivo setting. Twelve partially edentulous patients with different Kennedy classes underwent both a conventional impression (CI) and a computerized optical impression (COI) procedure. The CI was then digitized and compared with the COI data using 3D analysis software. Four different comparison situations were assessed: Whole Jaw (WJ), Mucosa with Residual Teeth (M_RT), Isolated Mucosa (IM), and Isolated Abutment Teeth (AT). Statistical analyses were conducted to evaluate group differences by quantifying the deviation values between the CIs and COIs. The mean deviations between the COIs and CIs varied significantly across the different comparison situations, with mucosal areas showing higher deviations than dental hard tissue. However, no statistically significant difference was found between the maxilla and mandible. Although COIM offers a no-pressure impression method that captures surfaces without irritation, it was found to capture mucosa less accurately than dental hard tissue. This discrepancy can likely be attributed to software algorithms that automatically filter out mobile tissues. Clinically, these findings suggest that caution is required when using COIM for prosthetics involving mucosal tissues as deviations could compromise the fit and longevity of the prosthetic appliance. Further research is warranted to assess the clinical relevance of these deviations. [ABSTRACT FROM AUTHOR]

Objective To evaluate the effect of anatomical healing abutments for mandibular first molars on the morphological changes of gingival soft tissue after implant restoration, as well as on peri-implant gingival molding, food ingrowth and patient satisfaction, to provide a basis for clinical selection. Methods Twenty-six patients who received implant restoration for a single missing mandibular first molar between September 2020 and September 2021 at the Oral Implant Center of Changsha Stomatological Hospital were randomly divided into a control group (13 cases with 14 implants) and a trial group (13 cases with 14 implants), of which 12 were male and 14 were female; the trial group had anatomical healing abutments applied for 4 weeks and then underwent crown restoration, while the control group finished five time points (before the second stage surgery, 4 weeks after the second stage surgery, immediately after the crown restoration, 4 weeks after the crown restoration, and 12 weeks after the crown restoration). A 3Shape intraoral scanner was used to scan the jaw before and 4 weeks after the second stage surgery to quantify the soft tissue changes and compare the effect of the healing abutment on gingival molding between the two groups. The incidence of food impaction was recorded and compared between the two groups at 4 weeks and 12 weeks after crown restoration. Patient satisfaction was recorded and compared between the two groups immediately after crown restoration, 4 weeks after crown restoration and 12 weeks after crown restoration. Results Four weeks after implant surgery, it was observed that the gingival proximal and distal gingival papillae increased on the coronal side in the test group compared to the control group, 0.50 (0.26, 0.72) mm in the near-medium test group and 0.27 (0.24, 0.38) mm in the control group, with a statistically significant difference (P = 0.029), and 0.48 (0.26, 0.62) mm in the far-medium test group and 0.23 (0.13, 0.39) mm in the control group, with a statistically significant difference (P = 0.004). There was no statistically significant difference (P>0.05) in the buccolingual to gingival margin apex to coronal molding or in the buccolingual to lingual soft tissue at 0, 1, or 2 mm of the root of the middle 1/3 apex of the buccal and lingual gingival margins between the two groups. Compared to the control group, there was no statistically significant difference in the incidence of food impaction observed 4 weeks and 12 weeks after crown restoration in the test group (P>0.05). The satisfaction scores were higher in the trial group than in the control group immediately, 4 weeks, and 12 weeks after crown restoration, and the difference between the groups was statistically significant (P < 0.05). Conclusion The anatomical healing abutment for the implant mandibular first molar was superior to the finished healing abutment in terms of soft tissue contouring with an increase in the coronal aspect of the proximal and distal gingival papillae, resulting in high patient satisfaction.

Purpose: This in vitro study aimed to evaluate the effects of restorative materials and scanning aid conditions on the accuracy and time efficiency of intraoral scans. Materials and Methods: Identical anatomic contour crowns were fabricated using the following materials: hybrid ceramic, 3 mol% yttria‐stabilized tetragonal zirconia, 4 mol% yttria‐partially stabilized zirconia, 5 mol% yttria‐partially stabilized zirconia, cobalt–chromium (Co–Cr), resin, lithium disilicate, and feldspathic ceramic. The models were digitized and analyzed for accuracy (n = 10) under three scanning aid conditions (powder‐based, liquid‐based, and none). Additionally, the effect of metal restorations on the scan accuracy of other crowns was investigated. The scan time for complete arches was also recorded. One‐way analysis of variance, Welch analysis of variance, and post‐hoc comparison or independent t‐tests were used for trueness analysis, and the F‐test was used to examine precision (α = 0.05). Results: Significant differences were observed in the trueness of the different restorative materials under the no‐scanning aid condition (P < 0.05). In contrast, no statistically significant difference among the groups was observed with the powder‐ or liquid‐based scanning aid. For each restorative material, the no‐scanning aid condition showed significantly lower trueness than that with powder‐ or liquid‐based scanning aids. The presence of a Co–Cr crown did not affect the trueness of other restorations in the arch. The scan time efficiency significantly increased on applying a powder‐ or liquid‐based scanning aid. Conclusions: Using a scanning aid was effective to improve the scan accuracy of the tested restorative materials and scan time efficiency. Applying scanning aids to existing intraoral restorations can help improve prosthesis quality and reduce the need for clinical adjustment at the occlusal or proximal contacts. [ABSTRACT FROM AUTHOR]

Despite many advantages, digital impressions, when compared to the conventional one, produce contrasting results and their complete substitution is still under debate. This comparative study aims to test a way to perform a clinical evaluation of digital impression Accuracy and Trueness with a gypsum check. After calculating the Trueness, Precision, and Accuracy of the digital impressions, a gypsum check was fabricated and screwed on implant abutments. The impression was not considered reliable if the gypsum check fractured during the insertion. The gypsum check test was correlated to a cut-off of 100 µm Trueness. Mean Trueness was 151.19 ± 37.23 µm of the first optical impression and 125.47 ± 41.90 µm of the second optical impression. The Precision mean was 39.76 ± 10.89 µm. The mean Accuracy percentage was 98.69 ± 0.29%. The gypsum checks fractured 10 times on 42 tests, and in any case, the Trueness value was above the 100 µm cut off, with a p = 0.001. A gypsum check screwed onto an implant abutment could be considered a way to perform clinical measurement of Trueness, allowing the clinician to understand if the Trueness value is higher or lower than 100 µm and reflecting the reliability of digital impressions. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the performance of the indirect technique in peri‐implant soft tissue contour duplication after the delivery procedure in the anterior maxilla. Materials and Methods: Patients with single implant‐supported fixed restorations in the anterior maxilla were recruited. For the impression procedure, an intraoral scan was acquired by both the direct and the indirect techniques. For the delivery procedure, implants were randomly allocated into one of the two groups according to the approaches of digital impression preceding definite crown fabrication (A—direct technique; B—indirect technique) and were scanned again after the definite crown delivery. The stereolithography files were superimposed to analyze changes in peri‐implant soft tissue contour after the delivery procedure. The main outcomes were dimensional deviations of peri‐implant mucosa, and the secondary outcome was differences in the pink esthetic score (PES). Results: A total of 20 implants that underwent the complete workflow were included. After the delivery procedure, significant deviations in palatal tissue thickness between the provisional and definite crowns were observed in Group A but these were absent in Group B. Additionally, deviations in labial thickness (0.27 ± 0.12 mm vs. 0.08 ± 0.09 mm) and palatal thickness (0.17 ± 0.15 mm vs. 0.03 ± 0.08 mm), and labial volume of soft tissue (1.87 ± 0.94 mm3 vs. 0.75 ± 0.74 mm3) in Group A were significantly higher than those in Group B. No significant differences in PES were found. Conclusion: The indirect technique of scanning the provisional crown can more accurately duplicate the peri‐implant soft tissue contour than the direct technique, resulting in a smaller deviation of the soft tissue in the delivery procedure. [ABSTRACT FROM AUTHOR]

Background: One of the rarest complications of fixed orthodontic retention is inadvertent tooth movement of the teeth bonded to the retainer. A 25-year-old patient presented at the orthodontist as she was preoccupied about the position of the lower teeth. The aim of this case report was to present a follow-up of anterior teeth alignment after fixed retainer removal and to analyze the structure of the removed fixed orthodontic retainer in a patient suffering from a twist effect. Materials and Methods: The retainer that caused inadvertent movement has been removed, and subsequent teeth displacement was assessed with scan superimposition. The retainer structure and diameter were analyzed with a laser confocal microscope. Results: The superimposition showed significant improvements in the position of the teeth. The sole removal of the activated retainer resulted in a partial self-correction of the twist effect. Under microscopic observation, changes in the dimensions of the wire were found but were too small to cause significant changes in tooth position. Conclusions: A fixed retainer should always be removed when a twist effect is diagnosed. The wire sections covered with composite are less likely to untwist. In the presented case, the changes in the dimensions of the round retainer wire could not have led to changes in the teeth’s positions.

Abstract Purpose To evaluate the volumetric stability of peri-implant soft and hard tissue prospectively, this study compared immediate versus delayed implants placed in the anterior esthetic region. Methods This non-randomized controlled clinical study included 25 patients, who received an immediate (type 1) or a delayed (type 4) implant placement for the replacement of a single anterior tooth. The anterior maxillae were intraorally scanned at three timepoints: before surgery (S0), 6 months (S1), and 12 months (S2) after surgery. A specific region of interest (ROI), divided into marginal and apical regions, was determined and superimposed for volumetric changes analysis. At 6 and 12 months, the probing depth (PD), bleeding/suppuration on probing (BOP/SUP), modified plaque index (PI), keratinized mucosa (KM) width, mucosal recession (MR), and implant stability (PTV) by means of periotest were recorded. Results Between S0–S2, tissue surrounding immediate implants was reduced in 0.37 ± 0.31 mm, whereas delayed implants gained 0.84 ± 0.57 mm mean tissue volume. Peri-implant tissue loss at type 1 implants occurred primarily in the marginal section of the ROI (0.42 ± 0.31 mm), whereas tissue gain at type 4 implants occurred mainly in the apical section (0.83 ± 0.51 mm). These values were significantly different between both groups for the entire ROI (p = 0.0452) and the marginal region (p = 0.0274). In addition, the mean buccal KM width around type 1 implants was significantly wider in comparison with the type 4 implants group after 12 months (p = 0.046). There were no significant differences between groups regarding PD, BOP/SUP, or PTV. Conclusions The results suggest that type 1 implants placed in the esthetic region experience more tissue loss than type 4 implants, thus marginal tissue remodeling should be considered for planning immediate implants placement in the anterior maxillae. Graphical Abstract

PURPOSE. To compare the sagittal condylar inclination (SCI) in dentate individuals measured by the different methods with mechanical articulator (MA), virtual articulator (VA), and a jaw tracking device (JTD) system. MATERIALS AND METHODS. A total of 22 healthy dentate participants were enrolled in this study. For MA workflow, the SCI was obtained by a semi-adjustable articulator with protrusive interocclusal records. The SCI was also set on a VA by aligning intraoral scan (IOS) with cone beam computed tomography (CBCT) and facial scan (FS), respectively. These virtual workflows were conducted in a dental design software, namely VAIOS-CBCT and VAIOS-FS. Meanwhile, a JTD system was also utilized to perform the measurement. Intraclass correlation was used to assess the repeatability within workflows. The bilateral SCI values were compared by Wilcoxon matched-pairs signed rank test for each workflow, and Kruskal-Wallis test and post hoc p-value Bonferroni correction were used to compare the differences among four workflows. The agreement of VAIOS-CBCT, VAIOS-FS, and JTD compared with MA was evaluated by Bland-Altman analysis. RESULTS. Intraclass correlation of the SCI revealed a high degree of repeatability for each workflow. There were no significant differences between the left and right sides (P > .05), except for VAIOS-CBCT (P = .028). Significant differences were not found between MA and VAIOS-FS (P > .05). Bland-Altman plots indicated VAIOS-CBCT, VAIOS-FS, and JTD were considered to substitute MA with high 95% limits of agreement. CONCLUSION. The workflow of VAIOS-FS provided an alternative approach to measure the SCI compared with MA. [ABSTRACT FROM AUTHOR]

Introduction: This paper is a comprehensive treaty about the variables that influence the transfer of the position of an implant to the laboratory when using a digital workflow. Objective: The aim is to provide operators and manufacturers with a guide on how to improve certain aspects of the digital workflow specific to the fabrication of implant‐supported restorations. Overview: It addresses intraoral scanning issues and CAD software issues. In the former, the variables that play a part in the quality of the scan file are investigated: the implant scan body, the IOS and the operator. For the latter, instead, the focus is on those aspects that still today may create inaccuracies in the workflow and in the final product being fabricated: the identification of the specific implant placed in the patient and the generation of a virtual model with the representation of that implant platform correctly positioned in the three dimensions of space. Suggestions and recommendations are given to improve the control on the quality of the digital workflow's output. Conclusion: In a digital workflow for the fabrication of an implant‐supported restoration, the selection and use of the implant scan body, the use of an effective scan strategy and the appropriateness of the best fit function in the CAD software, that is, the procedure of superimposing the library of geometric shapes of the ISB linked to the implant with the shape acquired intraorally, are variables that can influence the positional precision of the FDP. Clinical Significance: Fully understanding the importance of the information enclosed in the ISBs themselves can be crucial in the digital workflow. A proper ISB's selection, a correct scan of the ISB's shape and an accurate CAD superimposition of the ISB's library can lead the clinician to reduce the variables that affect the final result in daily practice. [ABSTRACT FROM AUTHOR]

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