The Scalloped Surgical Guide as an Alternative to Flat Bone Reduction Guide in Full-Arch Implant Restoration.

The goal of this clinical report was to present an alternative to traditional flat bone reduction guides, using a custom-designed 3-dimensional (3D)-printed guide according to the future gingival margin of the planned dentition. A 61-year-old woman with concerns regarding her smile appearance was presented. The initial examination revealed excessive gingival show accompanied by excessive overjet. The dentition was in a failing situation. The proposed treatment plan, relying on the sufficient amount of bone and keratinized tissue, consisted of recontouring of the alveolar ridge and gingiva and placement of 6 implants and an FP-1 prosthesis after extraction of all remaining maxillary teeth. Digital smile design was completed, and a fully digitally guided surgery was planned. This consisted of using 3 surgical guides, starting with the fixation pin guide, continuing with the scalloped hard- and soft-tissue reduction guide, and finally the implant placement template. Following the surgery, the patient received a temporary restoration, and on the 4-month follow-up, a new polymethyl meta-acrylate temporary prosthesis was delivered. The patient's 7-month follow-up is presented in the article. The report of this triple-template guided surgery indicated that digital 3D planning is a considerably predictable tool to properly establish and evaluate future occlusal plane, smile line, and lip support. Scalloped guides seem to be an excellent alternative to conventional bone reduction guides since they require less bone removal and improve patient comfort during surgery.

The Scalloped Surgical Guide as an Alternative to Flat Bone Reduction Guide in Full-arch Implant Restoration.

AIM: The goal of this clinical report was to present an alternative to traditional flat bone reduction guides, using a custom-designed 3D printed guide according to the future gingival margin of the planned dentition. MATERIALS AND METHODS: A 61-year-old female with concerns regarding her smile appearance was presented. The initial examination revealed excessive gingival show accompanied by excessive overjet. The dentition was in a failing situation. The proposed treatment plan, relying on the sufficient amount of bone and keratinized tissue, consisted of re-contouring of the alveolar ridge and gingiva and placement of six implants and a FP-1 prosthesis after extraction of all remaining maxillary teeth. RESULTS: Digital smile design was completed, and a fully-digitally-guided surgery was planned. This consisted of utilizing three surgical guides. Starting with the fixation pin guide and continuing with the scalloped hard and soft tissue reduction guide and finally, the implant placement template. Following the surgery, the patient received a temporary restoration and on the 4-month follow-up, a new poly-methyl meta-acrylate temporary prosthesis was delivered. The patient's 7-month follow-up is presented in the paper. CONCLUSIONS: The report of this triple-template guided surgery indicated that digital 3D planning is a considerably predictable tool to properly establish and evaluate future occlusal plane, smile line, and lip support. Scalloped guides seem to be an excellent alternative to conventional bone reduction guides since they require less bone removal and improve patient comfort during surgery.

Influence of exposure protocol, voxel size, and artifact removal algorithm on the trueness of segmentation utilizing an artificial-intelligence-based system.

PURPOSE: To evaluate the effects of exposure protocol, voxel sizes, and artifact removal algorithms on the trueness of segmentation in various mandible regions using an artificial intelligence (AI)-based system. MATERIALS AND METHODS: Eleven dry human mandibles were scanned using a cone beam computed tomography (CBCT) scanner under differing exposure protocols (standard and ultra-low), voxel sizes (0.15 mm, 0.3 mm, and 0.45 mm), and with or without artifact removal algorithm. The resulting datasets were segmented using an AI-based system, exported as 3D models, and compared to reference files derived from a white-light laboratory scanner. Deviation measurement was performed using a computer-aided design (CAD) program and recorded as root mean square (RMS). The RMS values were used as a representation of the trueness of the AI-segmented 3D models. A 4-way ANOVA was used to assess the impact of voxel size, exposure protocol, artifact removal algorithm, and location on RMS values (α = 0.05). RESULTS: Significant effects were found with voxel size (p < 0.001) and location (p < 0.001), but not with exposure protocol (p = 0.259) or artifact removal algorithm (p = 0.752). Standard exposure groups had significantly lower RMS values than the ultra-low exposure groups in the mandible body with 0.3 mm (p = 0.014) or 0.45 mm (p < 0.001) voxel sizes, the symphysis with a 0.45 mm voxel size (p = 0.011), and the whole mandible with a 0.45 mm voxel size (p = 0.001). Exposure protocol did not affect RMS values at teeth and alveolar bone (p = 0.544), mandible angles (p = 0.380), condyles (p = 0.114), and coronoids (p = 0.806) locations. CONCLUSION: This study informs optimal exposure protocol and voxel size choices in CBCT imaging for true AI-based automatic segmentation with minimal radiation. The artifact removal algorithm did not influence the trueness of AI segmentation. When using an ultra-low exposure protocol to minimize patient radiation exposure in AI segmentations, a voxel size of 0.15 mm is recommended, while a voxel size of 0.45 mm should be avoided.

The Accuracy of Guided Implant Surgery With Different Fields of View of Cone-Beam Computerized Tomography.

Although a smaller size field of view (FOV) of cone-beam computerized tomography (CBCT) reduces radiation exposure, its effect on the accuracy of static computer-aided implant surgery (s-CAIS) remains unknown. This study aimed to evaluate the impact of the size of FOV on the accuracy of s-CAIS and to investigate if the arch affects this effect. A total of 32 implant sites on 8 identical scannable models (maxillae and mandibles) were randomly allocated to 2 FOV sizes: test (5 × 5 cm) and control (10 × 10 cm). All models were scanned with an intraoral scanner (IOS). With the registration of the surface scan and CBCT image, a prosthetic-driven implant position was planned. Following the fabrication of surgical templates, a single-blinded surgeon placed all implants with the fully guided s-CAIS protocol. IOS captured the implant positions with the scan body attached. Implant-planning software measured the angular deviation, 3-dimensional (3D) deviation at the crest, and 3D deviation at the apex between preplanned and actual implant positions. Two-way analysis of variance was used to analyze the effect of FOV and arch on the deviations. The size of FOV did not show a significant effect (P > .198) on angular deviation, 3D deviation at the crest, or 3D deviation at the apex. No significant difference was found when comparing the effect of the size of FOV between the maxillary and mandibular implants. In conclusion, the use of small FOV CBCT demonstrated comparable accuracy of s-CAIS to the use of medium FOV CBCT.

Comparison of mesiodistal angulations of premolars and molars in anterior open bite subjects with different sagittal malocclusions: A retrospective study.

INTRODUCTION: Mesiodistal angulation of premolars and molars can be altered by forces of open bite malocclusion. The aim of this study was to compare the mesiodistal angulations of the posterior teeth in class I, II, and III individuals with anterior open bite (AOB) versus individuals with harmonious occlusion. METHODS: This comparative cross-sectional study used 299 lateral head radiographs of individuals with permanent dentition. There were 4 groups (harmonious occlusion [n=89], Class I open bite [OB] [n=75], Class II OB [n=66], and Class III OB [n=69]). Premolar (1UPM, 2UPM) and molar (1UM, 2UM) angulations were measured relative to the occlusal plane and the palatal or mandibular plane by a trained and calibrated evaluator. ANOVA and Scheffe tests were used for statistical analyses (P<0.05). RESULTS: The mesial angulation of the upper premolars showed greater angulation of between approximately 2° and 5° in the OB groups compared to the harmonious occlusion group (P<0.05). Only in the Class II OB group did the first and second upper molars show distal angulation in relation to the palatal plane (1UM 81.85°±5.42°; 2UM 75.32±7.4°) (P<0.05). The Class III OB group presented the greatest distal angulations of the lower premolars and molars (between 3° to 5° of difference, P<0.05) in relation to those of the harmonious occlusion group. CONCLUSIONS: The upper first premolars in all the AOB groups and the lower second premolars in the Class II OB group had greater mesioangulation. Additionally, the upper molars of the Class II OB group and the lower molars of the Class III OB group showed distoangulation compared with the molars in the group with harmonious occlusion.

Conservative Treatment of Bilateral Impacted Mandibular Canines Traction.

The objectives of the treatment of impacted canines differ according to the characteristics of dental malocclusion. Traction of the tooth is a conservative and viable alternative, which allows for maintaining stability and occlusal function. The following case report describes the treatment of an 11.6-year-old female patient, who presented bilateral impaction of mandibular canines in contact with the midline, mixed dentition in the inter-transitional period, class I angle malocclusion, with light crowding teeth. The treatment comprised three phases. The first phase, verticalization of the mandibular canines in mixed dentition, was performed to pull the impacted bilateral mandibular canines towards the dental arch to achieve their verticalization, maintaining the molar relationship, and the position of the upper and lower incisors. In the second phase, osteogenic rest was planned to relieve post-traction stress while awaiting the replacement of the mixed dentition. Finally, the third phase in permanent dentition was to align and level canines within the arch after extraction of the deciduous canines. For the viability of the permanent mandibular canines in the dental arch, orthosurgical traction was implemented, with a traction system with closed nickel-titanium coil springs with a transitory rigid dental-mucous-supported anchorage device, which allowed control and protection of the adjacent teeth and movements with helical forces of a controlled three-dimensional range. The results of the treatment were adequate, achieving consolidated molar and canine relationships, overjet, overbite, and optimal facial balance.

Concordance of the facial biotype between Bjork-Jarabak cephalometrics and photographic analysis of the facial opening angle.

Background: Analysis of the facial biotype can provide useful information for orthodontic diagnosis and can determine the type of growth of a patient to guide orthodontic treatment. The objective of this study was to determine the concordance of the facial biotype according to Bjork-Jarabak cephalometric analysis and photographic analysis of the angle of facial opening in Peruvian individuals. Material and Methods: This retrospective study included 244 cephalometric radiographs and frontal photographs of the same patients obtained from a database. The facial biotype (mesofacial, brachyfacial, or dolichofacial) was determined with the Björk-Jarabak polygon (cephalometric) and the angle of facial opening (photographic). Two trained investigators performed all the measurements. The concordance of the facial diagnosis was determined using correlations of the interclass coefficient and the kappa test. p<0.05. Results: In cases with a mesofacial biotype, both analyses coincided in 60 individuals (68.2%), while in those diagnosed with a dolichofacial biotype, the analyses only coincided in 17 individuals (10.4%). There was no concordance between the two methods regarding the brachyfacial biotype since according to the angle of facial opening none of the individuals presented a brachyfacial biotype (kappa weighted test= 0.020, p=0.586). Conclusions: Cephalometric and photographic analyses should be complementary and one should not substitute the other. Attention should be focused on dolichofacial and brachyfacial biotypes, which showed less concordance between evaluations. So, more studies are needed to follow this line of research. Key words:Facial biotype, cephalometry, photography, facial type, radiography.

Evaluation of the follicular space volume of lower third molars with different impaction positions and angulations: A cone-beam computed tomography and histopathological study.

Objective: To quantify the volume of the follicular spaces of impacted lower third molars (ILTMs) with different impaction positions and angulations using cone-beam computed tomography (CBCT) and to determine its association with the histopathological findings. Study design: This study included 103 ILTMs of 33 men and 70 women aged 18-46 years (mean age, 29.18 years). The follicular space volumes were measured on CBCT by manual segmentation and correlated with the histopathological diagnosis of each ILTM having different impaction positions and angulations. Statistical Product and Service Solutions, version 24, was used for statistical analyses by applying the t-test and binary logistic regression and multiple linear regression tests (p < 0.05). Results: Overall, 83 (80.6%) dental follicles presented a non-pathological diagnosis (mean follicular volume, 0.10 cm3), whereas 20 (19.4%) presented a pathological diagnosis (mean follicular volume, 0.32 cm3; p = 0.001). Similarly, the impaction depth in Position C cases was associated with a pathological diagnosis (p = 0.010). Conclusion: The follicular volume of the ILTMs varied significantly in teeth with a histopathological diagnosis of a follicular cyst and was associated with the impaction depth, mainly in Position C cases, and its relationship with the mandibular ramus. A mean follicular volume of 0.32 cm3 was associated with a greater probability of a pathological diagnosis.

Physical, Mechanical, and Anti-Biofilm Formation Properties of CAD-CAM Milled or 3D Printed Denture Base Resins: In Vitro Analysis.

PURPOSE: To investigate surface characteristics (roughness and contact angle), anti-biofilm formation, and mechanical properties (mini-flexural strength) of computer-aided design and computer-aided manufacturing (CAD-CAM) polymethylmethacrylate (PMMA) polymer, and three-dimensional (3D) printed resin for denture base fabrication compared with conventional heat polymerized denture base resins. MATERIALS AND METHODS: A total of 60 discs and 40 rectangular specimens were fabricated from one CAD-CAM (AvaDent), one 3D printed (Cosmos Denture), and two conventional heat polymerized (Lucitone 199 and VipiWave) materials for denture base fabrication. Roughness was determined by Ra value; the contact angle was measured by the sessile drop method. The biofilm formation inhibition behavior was analyzed through Candida albicans adhesion, while mini-flexural strength test was done using a three-point bending test. The data were analyzed using descriptive and analytical statistics (α = 0.05). RESULTS: The CAD-CAM PMMA group showed the lowest C. albicans adhesion (log CFU/mL: 3.74 ± 0.57) and highest mini-flexural strength mean (114.96 ± 16.23 MPa). 3D printed specimens presented the highest surface roughness (Ra: 0.317 ± 0.151 µm) and lowest mini-flexural strength values (57.23 ± 9.07 MPa). However, there was no statistical difference between CAD-CAM PMMA and conventional groups for roughness, contact angle, and mini-flexural strength. CONCLUSIONS: CAD-CAM milled materials present surface and mechanical properties similar to conventional resins and show improved behavior in preventing C. albicans adhesion. Nevertheless, 3D printed resins present decreased mini-flexural strength.

Workflow for complete dentures fabrication in three appointments: A dental technique.

This technical report describes a novel workflow for complete denture fabrication designed to abbreviate the necessary steps for dental prostheses delivery by using a 3-appointment protocol in which preliminary impressions are made in the first session together with the registration of maxillary lip support, occlusal plane, and reference lines for tooth arrangement. A trial denture is fabricated with conventional or computer-aided design and computer-aided manufacturing procedures and is evaluated in the second appointment for esthetics, the definitive impression, and the maxillomandibular relationship record to provide precise references for definitive denture fabrication.

Evaluation of the accuracy of buccal bone thickness measurement from cone beam computed tomography compared with histologic analysis.

STATEMENT OF PROBLEM: Three-dimensional radiographic assessment of buccal bone thickness and its integrity from cone beam computed tomography (CBCT) plays an essential role in immediate implant placement. However, the accuracy of CBCT measurements for the assessment of buccal bone thickness adjacent to maxillary anterior teeth is not well understood. PURPOSE: The purpose of this observational study was to evaluate the accuracy of measuring the buccal bone thickness of maxillary anterior teeth from CBCT compared with direct measurement from histologic sections. A secondary objective was to analyze whether a minimal level of buccal bone thickness of maxillary anterior teeth can be detected from the CBCT scan. MATERIAL AND METHODS: Five embalmed human cadavers with a complete anterior dentition were included in this study, providing 30 teeth for evaluation. After preparing reference notches at the gingival margin of each tooth, the anterior segments were scanned. The buccal bone thickness at 3, 5, and 7 mm from the notches was measured on the cross-sections obtained from the CBCT and histomorphometric images for a total of 90 sites. The CBCT measurements were compared with the histomorphometric measurements, and their agreement was assessed by using the Bland-Altman plots and intraclass correlation coefficients. The sensitivity and specificity of buccal bone detection were calculated from the CBCT scan. RESULTS: Histologic examination showed absence of the buccal bone in 29 sites (32%). The mean ±standard deviation thickness of the buccal bone was 0.52 ±0.05 mm (range: 0 to 1.97 mm) from the CBCT analysis and 0.40 ±0.05 mm (range: 0 to 1.67 mm) from histology. Measurements obtained from the CBCT sections significantly overestimated the buccal bone thickness when compared with the histologic evaluation (P=.001). The intraclass correlation coefficient of buccal bone thickness between the CBCT and histology was ≤0.53, an agreement considered as poor. The sensitivity of the CBCT as a diagnostic tool to detect the presence or absence of the buccal bone was 75.4%, and the specificity was 65.5%. CONCLUSIONS: The buccal bone thickness of maxillary anterior teeth was less than 2 mm at all sites as measured with both CBCT and histology evaluations. CBCT measurements had relatively low accuracy and reliability for the measurement of buccal bone thickness. These findings should be considered when using CBCT as a measuring tool for thin bone structures.

Three-Dimensional printed model for preclinical training in oral radiology.

INTRODUCTION: 3D printing is experiencing significant growth in the teaching and learning process. This study aims to present a 3D printed skull model for preclinical intraoral radiographic practice. MATERIALS AND METHODS: Two 3D printed mannequins were created. One mannequin used an STL file of a skull that was edited using two 3D modelling software (Meshmixer and Netfabb). The second mannequin was designed directly from a patient's segmented CBCT data and then converted into an STL file. Both mannequins were printed using fused deposition modelling (FDM) technology and polylactic acid (PLA) filament; teeth for the second mannequin were also printed using digital light processing (DLP). The printed skull bones were attached, the mandible was articulated to the articular fossa of the temporal bone, and the teeth were inserted into the alveoli. Intraoral radiographs of both mannequins were taken using a digital sensor (RVG 5100, Carestream). RESULTS: Both 3D printed mannequins showed satisfactory radiographic appearance, allowing geometric representation of each intraoral radiographic projection, regardless of STL file origin. Anatomical structures, such as the periodontal ligament space, zygomatic process of the maxilla and intermaxillary suture, were represented. The material cost of the first and second printed prototype was $34.00 and $39.00, respectively. CONCLUSIONS: The use of 3D printed models is presented as an alternative to artificial commercial phantoms for the preclinical training of intraoral radiographic techniques through the combined benefits of superior radiographic projection quality, the possibility of model manipulation and an affordable price.

The trueness of scans using one intraoral scanner in different partially edentulous conditions.

PURPOSE: To investigate the trueness of intraoral scanning in 8 commonly seen partially edentulous conditions. MATERIALS AND METHODS: A maxillary dentoform was modified into the 8 commonly seen partially edentulous conditions. Each modification was scanned with a laboratory desktop scanner. Each modification was then scanned 10 times (n = 10) with an intraoral scanner. All scans were exported as STL files and then imported into a surface matching software using the best-fit alignment method. The dimensional differences between the study STL files from the intraoral scanner were compared to the corresponding reference STL files. The measurements were calculated as the root mean square (RMS) and defined as the trueness of the intraoral scans. In addition to the RMS values, qualitative assessments were completed on the color maps. The color maps produced by the surface matching software were used to visualize the areas of deviation between scans from the intraoral scanner and their corresponding reference files. One-way analysis of variance (ANOVA), followed by pair-wise comparisons using Fisher's Protected Least Significant Difference were utilized to compare the differences between the groups in RMS values (α = 0.05). RESULTS: Partially edentulous condition significantly affected the trueness of the intraoral scans. Group 8 (Class IV) had significantly lower RMS (0.1878 ± 0.0455 mm) than all other groups (p < 0.001). Group 2 (Class II) and Group 7 (Class III modification I) are not significantly different from each other (Group 2: 0.5758 ± 0.0300 mm; Group 7: 0.5602 ± 0.0231 mm, p = 0.571), while they both had significantly higher RMS than all other groups (p < 0.001). The remaining groups showed the RMS values were within the range of 0.3001 ± 0.0891 mm (Group 6 - Class III with Long Edentulous Span) and 0.4541 ± 0.1039 mm (Group 1 - Class I). CONCLUSION: Different partially edentulous conditions affected the trueness of the scans generated from the selected intraoral scanner. Class IV edentulous condition had the highest intraoral scan trueness. It is unknown if RMS values are clinically significant, and the validity of using intraoral scans directly for PRDP fabrication will need further studies.

Sagittal Position of the Upper Incisor in Relation to the Forehead in Peruvian Individuals with Different Skeletal Relationships.

AIM: The aim of this study was to determine the sagittal position of the upper incisor considering Andrews' analysis based on the position of the forehead in Peruvian individuals with different skeletal relationships. MATERIALS AND METHODS: This retrospective, cross-sectional study included 212 lateral head radiographs of Peruvian individuals (males: 85, mean age 21.38 ± 6.88, and females: 127, mean age 21.18 ± 6.95), with different skeletal relationships (Class I group = 96, Class II group = 57, Class III group = 59). The values of the ANB, SNA, SNB angles as well as the forehead anterior limit line (FALL) and goal anterior limit line (GALL) points were identified in the radiographs, and then a vertical line was drawn in each point to determine if the upper incisor was positioned forward (protruded), backward (retruded) or within (adequate) these lines. Two trained and calibrated investigators performed all the measurements. The Chi-square test was used to evaluate associations. A p-value < 0.05 was considered statistically significant. RESULTS: Overall, the sagittal position of the upper incisor showed a significant association with the sagittal skeletal relationship (p = 0.001). The upper incisors showed an adequate position (41.7%), protruded position (56.10%), and retruded position (42.40%), for Class I, II, and III skeletal relationships, respectively, as highest percentages in each Class. Statistical significance was found for females only (p = 0.005). CONCLUSION: Skeletal Class I mainly showed an adequate position of the upper central incisor, whereas for Class II a protruded position was most frequently found, and Class III presented a retruded position. CLINICAL SIGNIFICANCE: Andrews' analysis based on the position of the forehead in Peruvian individuals is a valuable tool for orthodontic diagnosis. How to cite this article: Bazán-Mendoza JR, Arias-Modesto PB, Ruíz-Mora GA, et al. Sagittal Position of the Upper Incisor in Relation to the Forehead in Peruvian Individuals with Different Skeletal Relationships. J Contemp Dent Pract 2023;24(11):821-825.

Precision and accuracy assessment of single and multicamera three-dimensional photogrammetry compared with direct anthropometry.

OBJECTIVES: To assess the precision and accuracy of single-camera photogrammetry (SCP) and multicamera photogrammetry (MCP) compared with direct anthropometry (DA). MATERIALS AND METHODS: A total of 30 participants were recruited, and 17 soft tissue landmarks were identified and used to complete a total of 16 measurements. Using SCP and MCP, two three-dimensional (3D) images were acquired from each participant. All 3D measurements and direct measurements were measured twice by the same operator to assess intraexaminer repeatability. Intraclass coefficients (ICCs) were used to evaluate intraexaminer repeatability and interexaminer agreement of the methods. Nonparametric bootstrap analyses were used to compare the means of the measurements among the three methods. RESULTS: All three methods showed excellent intraexaminer repeatability (ICCs > 0.90), except interpupillary distance (ICC = 0.86) measured by SCP. Both SCP and MCP showed excellent interexaminer agreement (ICCs > 0.90), except interpupillary distance (ICC = 0.79), left gonion-pogonion (ICC = 0.74), and columella-subnasale-labrale superior angle (ICC = 0.86) measured by SCP. Overall, there was good agreement between methods, except for columella-subnasale-labrale superior angle (ICC = 0.40) between SCP and MCP. CONCLUSIONS: Both SCP and MCP techniques were found to be reliable and valid options for 3D facial imaging. SCP produced slightly larger mean values for several measurements, but the differences were within a clinically acceptable range. Because of the larger margin of errors, measurements including the gonial area and subnasale should be assessed with caution.

Evaluation of the accuracy of soft tissue thickness measurements with three different methodologies: An in vitro study.

BACKGROUND: Soft tissue thickness (STT) influences esthetics, peri-implant, and periodontal health. Non-invasive methods of STT evaluation include cone-beam computed tomography (CBCT) with Digital Imaging and Communications in Medicine (DICOM) files and registration of DICOM files with an intraoral scan or Standard Tessellation Language (STL) files. This study compares three methodologies: bone sounding, DICOM data alone, and DICOM and STL registration to absolute histomorphologic values. METHODS: Five human maxillas, including teeth numbers 6 to 11, provided 90 sites for analysis. For standardization, reference grooves were placed at the cervical margin and the long axis of each tooth. Direct measurements with a no. 25 K-file were completed at the facial soft tissues at 3.00, 5.00, and 7.00 mm from the apical marginal reference. Indirect measures were performed with implant planning software. Histological measurements were rendered with imaging software. One-way analysis of variance (ANOVA) was used to compare the three techniques for the differences from histologic measurements (α = 0.05). RESULTS: Seventy-two sites were included for final analysis. The overall mean histological STT (mSTT) was 0.73 ± 0.31 mm. Bone sounding overestimated mSTT, 0.22 ± 0.20 mm (P < 0.001); whereas, DICOM alone underestimated mSTT, -0.23 ± 0.19 mm (P < 0.001). DICOM and STL registration had non-statistically significant differences, -0.04 ± 0.21 mm (P = 0.429). Intraclass correlation coefficient (ICC) of DICOM and STL registration achieved the highest agreement with histology (ICC: 0.74). CONCLUSIONS: DICOM and STL file registration had the highest agreement with histological STT supporting the use of DICOM and STL registration for the evaluation of STT.

Use of a CAD-CAM Surgical Template to Improve Accuracy for Simultaneous Implant Removal, New Implant Placement, and Bone Graft.

A fractured implant is considered a catastrophic failure that leads to the loss of the implant and the prosthesis. Available methods of implant removal include the reverse screw technique, use of trephines, or osteotomies around the implant. In case of a fractured implant, the access hole for the reverse screw technique is impossible, leading to the need for an osteotomy. When the apical part of the fractured implant is embedded in bone, finding the piece may lead to a more ample osteotomy and significant bone loss, complicating future implant placement. This technique presented utilized a CAD-CAM surgical template that was designed with the purpose of improving accuracy in finding the fractured part with minimal osteotomy, allowing for simultaneous placement of a new implant in the same site, with additional bone graft, utilizing the same template.

Three-dimensional analysis of the posttreatment displacements of mandibular anterior teeth with rigid and flexible lingual retainers.

INTRODUCTION: The purpose of this study was to analyze any posttreatment changes in the positions of mandibular anterior teeth retained by 2 different fixed retention methods (rigid or flexible) and their effectiveness in minimizing postorthodontic tooth movement. METHODS: Thirty patients were selected for inclusion in this retrospective study. Group I consisted of 15 patients with 0.032-in stainless steel rigid retainers bonded to canines only. Group II consisted of 15 patients with 0.0215-in twisted stainless steel flexible retainer bonded to all mandibular anterior teeth. Geomagic Control (3DS Systems, Rock Hill, SC) software was used to quantify the changes between selected points. Paired t test was used for intragroup comparisons in all 3 coordinates, and an independent-sample t test was used for intergroup comparison. RESULTS: In the transverse dimension, significant intergroup differences were found in displacements of distoincisal points of the right lateral (P <0.05) and left central incisors (P <0.01). In the sagittal dimension, significant intergroup differences were found in the displacements of mesioincisal point of the right central incisor (P <0.05) and distoincisal point of the left central incisor (P <0.01). Examining total displacement, there were significant intergroup differences in mesioincisal point on the right central incisor, distoincisal point on the left lateral incisor (P <0.05). CONCLUSIONS: Our results suggested that central incisor contacts were more likely to shift with the rigid retainers, especially in sagittal and transverse dimensions. However, no statistically or clinically significant changes were noted in the third-order or vertical positions of the teeth with either retention method.

Concurrent Validity of Digital Image-based Postural Assessment as a Method for Measuring Thoracic Kyphosis: A Cross-Sectional Study of Healthy Adults.

OBJECTIVE: To analyze the concurrent validity of the Digital Image-based Postural Assessment (DIPA) method for identifying the magnitude and classification of thoracic kyphosis in adults. METHODOLOGY: On the same day and in the same place, thoracic kyphosis was assessed in 68 adults using 2 methods: the DIPA software protocol and radiography. The DIPA software provided angular values of thoracic kyphosis based on trigonometric relations, while with the radiograph, the curvature was calculated using the Cobb method. The following tests were applied in the statistical analysis: Pearson's correlation, Bland-Altman's graphic representation, root mean square error, and receiver operating characteristic (ROC) curve; α = 0.05. The reference angular values for the standard thoracic posture used in DIPA were determined with the ROC curve based on the Cobb angles. RESULTS: The correlation between the angles obtained for thoracic kyphosis using the DIPA and Cobb methods was found to be high (r = 0.813, P < .001), and the accuracy was ±4°. According to Bland-Altman's representation, the magnitudes provided by the DIPA software were in agreement with those of the Cobb method. In reference values for determining the standard posture of the thoracic spine, the ROC curve indicated good accuracy in diagnosing a decrease in thoracic kyphosis (with a value of 33.9°) and excellent accuracy in diagnosing thoracic hyperkyphosis (with a value 39.9°) when using DIPA. CONCLUSION: The DIPA postural assessment method is valid in the sagittal plane for identifying the magnitude of thoracic kyphosis in adults. Furthermore, it is accurate in diagnosing alterations in thoracic kyphosis.

Is There a Correlation Between Airway Volume and Maximum Constriction Area Location in Different Dentofacial Deformities?

PURPOSE: The purpose of the present study was to correlate the airway volume and maximum constriction area (MCA) with the type of dentofacial deformity in patients who required orthognathic surgery. MATERIALS AND METHODS: The present retrospective cohort study included orthognathic surgery patients selected from the private practice of one of us. The selected cases were stratified into 5 different groups according to the clinical and cephalometric diagnosis of their dentofacial deformity. The preoperative airway volume and anatomic location of the MCA were calculated using the airway tool of the Dolphin Imaging software module (Dolphin Imaging and Management Solutions, Chatsworth, CA) and correlated with the diagnosed dentofacial deformity. Differences in the pretreatment airway volumes and MCA location were compared among the deformities. RESULTS: The MCA location was more often the nasopharynx for maxillary deficiency and the oropharynx for mandibular deficiency deformities. The nasopharynx volume was significantly smaller statistically (P < .005) for maxillary deficiency plus mandibular excess compared with mandibular deficiency. The hypopharynx volume was significantly smaller statistically (P < .005) for vertical maxillary excess plus mandibular deficiency than for both maxillary deficiency and maxillary deficiency plus mandibular excess. No statistically significant difference was found among the different deformity groups in relation to the mean airway volume (P > .005). CONCLUSIONS: The location of the airway MCA seems to have a strong correlation with the horizontal position of the maxilla and mandible. The MCA in maxillary deficiencies (isolated or combined) was in the nasopharynx, and the MCA in mandibular deficiencies (isolated or combined) was in the oropharynx. Clinicians should consider these anatomic findings when planning the location and magnitude of orthognathic surgery movements to optimize the outcomes.