Ultrasound Evaluation of Retrocervical and Parametrial Deep Endometriosis on the Basis of Surgical Anatomic Landmarks.

STUDY OBJECTIVES: To assess the value of combined transvaginal/transabdominal ultrasonographic evaluation performed by experienced examiners for deep infiltrating endometriosis (DIE) lesions of the retrocervical (torus uterinus and uterosacral ligaments) and parametrial areas and summarize the features and anatomic criteria for identification of these lesions and their extent in the above-mentioned pelvic compartments. DESIGN: Retrospective study. SETTING: A specialized endometriosis center in Avellino, Italy. PATIENTS: A retrospective cohort of patients who underwent laparoscopic surgery for clinically suspected DIE between January 1, 2014, and December 31, 2018, with a dedicated ultrasound (US) evaluation performed no more than 1 month before the intervention. INTERVENTIONS: Preoperative US findings and surgical reports were reviewed. Using the findings of laparoscopic surgery as the gold standard, the sensitivity and specificity of preoperative US evaluation for retrocervical and parametrial endometriotic lesions were calculated with the corresponding 95% confidence intervals. MEASUREMENTS AND MAIN RESULTS: A total of 4983 patients were included. US evaluation showed high diagnostic accuracy for DIE detection in the examined pelvic compartments, with sensitivity and specificity of 97% to 98% and 98% to 100%, respectively, for both retrocervical (torus uterinus and uterosacral ligaments insertion) and parametrial lesions. CONCLUSION: Parametrial extension of DIE indicates major surgical technical difficulties and risk of complications, and urologic and nerve-sparing procedures may be required in such cases. Preoperative evaluation of such scenarios will allow proper counseling of patients and facilitate adequate surgical planning in referral centers; moreover, when necessary, it can guide the constitution of a dedicated multidisciplinary surgical team as an alternative to treatment by a pelvic surgeon alone. Detailed imaging evaluation of DIE lesions and their extension is crucial for clinical management of affected patients. It can facilitate optimization of surgical timing and strategies, thereby potentially preventing ineffective, or even harmful, repeated procedures.

A landmark-based 3D analysis reveals a narrower tibial plateau and patella in trochlear dysplastic knees.

PURPOSE: The trochlear dysplastic femur has a specific morphotype previously characterised by not only dysplastic features of the trochlea but also by specific features of the notch and posterior femur. In this study the morphology of the tibia and patella was investigated to gain further insight in the complete geometrical complexity of the trochlear dysplastic knee. METHODS: Arthro-CT scan-based 3D models of 20 trochlear dysplastic and 20 normal knees were uniformly scaled and landmarks and landmark-based reference planes were created to quantify a series of morphometric characteristics of the tibia and patella. RESULTS: In the mediolateral direction, the 3D-analysis revealed a 3% smaller medial tibial plateau (30.4 ± 1.6 mm vs 31.5 ± 1.6 mm), a 3% smaller overall width of the tibial plateau (73.6 ± 2.0 mm vs 75.7 ± 2.0 mm), a 16% smaller medial facet (17.3 ± 2.2 mm vs 20.1 ± 1.3 mm) and a 4% smaller overall width of the patella (41.7 ± 2.5 mm vs 43.4 ± 2.3 mm) in trochlear dysplastic knees. In the anteroposterior direction, the lateral tibial plateau of trochlear dysplastic knees was 5% larger (37.2 ± 2.3 mm vs 35.5 ± 3.1 mm). A correlation test between the width of the femur and the width of the tibia revealed that trochlear dysplastic knees show less correspondence between the femur and tibia compared to normal knees. CONCLUSION: Significant differences in the morphology of the tibial plateau and patella were detected between trochlear dysplastic and normal knees. Both in the trochlear dysplastic tibial plateau and patella a narrower medial compartment leads to a significant smaller overall mediolateral width. These findings are important for the understanding of knee biomechanics and the design of total knee arthroplasty components. LEVEL OF EVIDENCE: III.

Soft tissue changes: a comparison between changes caused by the construction bite and by successful treatment with a modified Twin-block appliance.

Background/objectives: Functional appliances are commonly used to correct Class II malocclusion. This study aimed to compare the facial soft tissue changes in Caucasians between pre-treatment and with the construction bite versus pre-treatment and completion of treatment with a modified Twin-block appliance (MTBA). Materials and methods: Fifty-eight Caucasian subjects with Class II division 1 malocclusion had 3D stereophotogrammetric images captured pre-treatment (T1), with the construction bite (T2), and on completion of MTBA treatment (T3). Twenty-six landmarks were located on each image and 10% were re-landmarked 1 month later. Soft-tissue linear and volumetric changes (T1-T2 and T1-T3) were analyzed using linear mixed effect models (SAS® Version 9.4, www.sas.com). Results: Forty-seven subjects [mean age 13.2 (SD 1.7) years] completed treatment [mean duration 9.8 (SD 3.8) months]. Differences between the changes from T1 to T2 versus T1 to T3 for upper facial and upper lip landmarks were insignificant (all P > 0.05) except for nasion, orbitale right, pronasale, and subnasale. For the same comparisons, lower lip and chin landmarks changed significantly (all P < 0.05) as did facial soft tissue volume (P< 0.0001). Limitations: There was no control group. Conclusion: The facial soft tissue changes from pre-treatment to with the construction bite were considerably more than those from pre-treatment to completion of treatment with a MTBA. Implication: With MTBA treatment, the soft tissue changes from pre-treatment to with the construction bite in situ, overestimate those from pre- to post-treatment.

Diagnostic value of integrated PET/MRI for detection and localization of prostate cancer: Comparative study of multiparametric MRI and PET/CT.

PURPOSE: To evaluate the diagnostic value of integrated positron emission tomography/magnetic resonance imaging (PET/MRI) compared with conventional multiparametric MRI and PET/computed tomography (CT) for the detailed and accurate segmental detection/localization of prostate cancer. MATERIALS AND METHODS: Thirty-one patients who underwent integrated PET/MRI using 18 F-choline and 18 F-FDG with an integrated PET/MRI scanner followed by radical prostatectomy were included. The prostate was divided into six segments (sextants) according to anatomical landmarks. Three radiologists noted the presence and location of cancer in each sextant on four different image interpretation modalities in consensus (1, multiparametric MRI; 2, integrated 18 F-FDG PET/MRI; 3, integrated 18 F-choline PET/MRI; and 4, combined interpretation of 1 and 18 F-FDG PET/CT). Sensitivity, specificity, accuracy, positive and negative predictive values, likelihood ratios, and diagnostic performance based on the DOR (diagnostic odds ratio) and NNM (number needed to misdiagnose) were evaluated for each interpretation modality, using the pathologic result as the reference standard. Detection rates of seminal vesicle invasion and extracapsular invasion were also evaluated. RESULTS: Integrated 18 F-choline PET/MRI showed significantly higher sensitivity than did multiparametric MRI alone in high Gleason score patients (77.0% and 66.2%, P = 0.011), low Gleason score patients (66.7% and 47.4%, P = 0.007), and total patients (72.5% and 58.0%, P = 0.008) groups. Integrated 18 F-choline PET/MRI and 18 F-FDG PET/MRI showed similar sensitivity and specificity to combined interpretation of multiparametric MRI and 18 F-FDG PET/CT (for sensitivity, 58.0%, 63.4%, 72.5%, and 68.7%, respectively, and for specificity, 87.3%, 80.0%, 81.8%, 72.7%, respectively, in total patient group). However, integrated 18 F-choline PET/MRI showed the best diagnostic performance (as DOR, 11.875 in total patients, 27.941 in high Gleason score patients, 5.714 in low Gleason score groups) among the imaging modalities, regardless of Gleason score. Integrated 18 F-choline PET/MRI showed higher sensitivity and diagnostic performance than did integrated 18 F-FDG PET/MRI (as DOR, 6.917 in total patients, 15.143 in high Gleason score patients, 3.175 in low Gleason score groups) in all three patient groups. CONCLUSION: Integrated PET/MRI carried out using a dedicated integrated PET/MRI scanner provides better sensitivity, accuracy, and diagnostic value for detection/localization of prostate cancer compared to multiparametric MRI. Generally, integrated 18 F-choline PET/MRI shows better sensitivity, accuracy, and diagnostic performance than does integrated 18 F-FDG PET/MRI as well as combined interpretation of multiparametric MRI with 18 F-FDG PET/CT. LEVEL OF EVIDENCE: 2 J. Magn. Reson. Imaging 2017;45:597-609.

Posterior Decentering of the Humeral Head on Shoulder MR Arthrography: Significant Association With Posterior Synovial Proliferation.

OBJECTIVE: The purpose of this study is to analyze MRI findings associated with posterior decentering of the humeral head on shoulder MR arthrogram. MATERIALS AND METHODS: A total of 255 MR arthrograms were obtained during a 10-month period. MR arthrograms in patients with posterior decentering of the humeral head (n = 33) were reviewed and compared with those of randomly selected control group without posterior decentering (n = 66). MR arthrograms were retrospectively evaluated by two observers for posterior factors (posterior synovial proliferation, posterior capsular thickening, and posterior labral abnormality), rotator cuff factors related to fatty degeneration, glenoid version, and anterior factors (subcoracoid bursa effusion and rotator interval tear). The chi-square test, Fisher exact test, and linear-by-linear association were used for comparison of categoric data; the t test was used for comparison of the glenoid version; and multivariate stepwise logistic regression analysis was performed. RESULTS: At univariate analysis, posterior synovial proliferation (27.3% [9/33] in the posterior decentering group vs 6.1% [4/66] in the control group; p = 0.003); posterior capsule thickening (21.2% [7/33] vs 0.0% [0/66]; p < 0.001); fatty infiltration of the supraspinatus, infraspinatus, and teres minor (linear-by-linear association values, 7.944, 10.496, and 5.985, respectively; p = 0.005, 0.001, and 0.014, respectively); and rotator interval tear (51.5% [17/33] vs 30.3% [20/66]; p < 0.04) were more frequently found in the posterior decentering group, with a statistically significant difference. At multivariate analysis, only the posterior synovial proliferation was significantly associated with posterior decentering of the humeral head (odds ratio, 7.675; 95% CI, 2.159-27.288). CONCLUSION: Posterior decentering of the humeral head is most significantly associated with posterior synovial proliferation. In addition, rotator cuff interval abnormalities and rotator cuff atrophy are associated with posterior decentering of the humeral head to a lesser extent. Awareness of the association of the posterior decentering of the humeral head with the factors described here will facilitate the effective interpretation of routine MR arthrograms in daily practice.

Adhesive Capsulitis of the Shoulder Joint: Value of Glenohumeral Distance on Magnetic Resonance Arthrography.

OBJECTIVE: To evaluate the usefulness of glenohumeral distance (GHD) on axial images of magnetic resonance (MR) arthrography for diagnosis of adhesive capsulitis and to compare this finding with previously reported classic MR arthrographic findings of adhesive capsulitis. MATERIALS AND METHODS: Our study was approved by the institutional ethical review board of our institute. We evaluated 41 patients (M-F, 35:6; mean age, 46 years; adhesive capsulitis, 21; no adhesive capsulitis, 20) who underwent MR arthrography. Two radiologists measured GHD, width of the axillary recess, and capsular thickness in consensus. The GHD was measured from the subchondral bone of the glenoid fossa to the subchondral bone of the humeral head at the level of the midline of the humeral head. Glenohumeral distance (anterior, middle, posterior, and mean), width of the axillary recess, and capsular thickness (anterior, posterior, and mean) were compared in the adhesive capsulitis and no adhesive capsulitis groups using the Mann-Whitney U test. RESULTS: The mean GHD of the no adhesive capsulitis group was longer than that of the adhesive capsulitis group. The length differences were statistically significant (P < 0.05). The mean width of the axillary recess of the no adhesive capsulitis group was significantly wider than that of the adhesive capsulitis group (P < 0.001). The mean capsular thickness of the no adhesive capsulitis group was significantly thinner than that in the adhesive capsulitis group (P = 0.001). CONCLUSIONS: A decreased GHD on MR arthrography can be another useful feature to diagnose adhesive capsulitis in addition to previously presented radiologic features such as capsular thickening and reduced axillary recess capacity.

Influence of different setups of the Frankfort horizontal plane on 3-dimensional cephalometric measurements.

INTRODUCTION: The Frankfort horizontal (FH) is a plane that intersects both porions and the left orbitale. However, other combinations of points have also been used to define this plane in 3-dimensional cephalometry. These variations are based on the hypothesis that they do not affect the cephalometric analysis. We investigated the validity of this hypothesis. METHODS: The material included cone-beam computed tomography data sets of 82 adult subjects with Class I molar relationship. A third-party method of cone-beam computed tomography-based 3-dimensional cephalometry was performed using 7 setups of the FH plane. Six lateral cephalometric hard tissue measurements relative to the FH plane were carried out for each setup. Measurement differences were calculated for each pair of setups of the FH plane. The number of occurrences of differences greater than the limits of agreement was counted for each of the 6 measurements. RESULTS: Only 3 of 21 pairs of setups had no occurrences for the 6 measurements. No measurement had no occurrences for the 21 pairs of setups. Setups based on left or right porion and both orbitales had the greatest number of occurrences for the 6 measurements. CONCLUSIONS: This investigation showed that significant and undesirable measurement differences can be produced by varying the definition of the FH plane.

A comparison of radiographic anatomic axis knee alignment measurements and cross-sectional associations with knee osteoarthritis.

OBJECTIVE: Malalignment is associated with knee osteoarthritis (KOA), however, the optimal anatomic axis (AA) knee alignment measurement on a standard limb radiograph (SLR) is unknown. This study compares one-point (1P) and two-point (2P) AA methods using three knee joint centre locations and examines cross-sectional associations with symptomatic radiographic knee osteoarthritis (SRKOA), radiographic knee osteoarthritis (RKOA) and knee pain. METHODS: AA alignment was measured six different ways using the KneeMorf software on 1058 SLRs from 584 women in the Chingford Study. Cross-sectional associations with principal outcome SRKOA combined with greatest reproducibility determined the optimal 1P and 2P AA method. Appropriate varus/neutral/valgus alignment categories were established using logistic regression with generalised estimating equation models fitted with restricted cubic spline function. RESULTS: The tibial plateau centre displayed greatest reproducibility and associations with SRKOA. As mean 1P and 2P values differed by >2°, new alignment categories were generated for 1P: varus <178°, neutral 178-182°, valgus >182° and for 2P methods: varus <180°, neutral 180-185°, valgus >185°. Varus vs neutral alignment was associated with a near 2-fold increase in SRKOA and RKOA, and valgus vs neutral for RKOA using 2P method. Nonsignificant associations were seen for 1P method for SRKOA, RKOA and knee pain. CONCLUSIONS: AA alignment was associated with SRKOA and the tibial plateau centre had the strongest association. Differences in AA alignment when 1P vs 2P methods were compared indicated bespoke alignment categories were necessary. Further replication and validation with mechanical axis alignment comparison is required.

Assessment of Liliequist membrane by 3D-SPACE technique at 3 T.

INTRODUCTION: Liliequist membrane (LM) is the most important anatomic structure for the success of endoscopic third ventriculostomy (ETV). Identification of this membrane is difficult with conventional MRI techniques. The purpose of this retrospective study is to determine the impact of three-dimensional sampling perfection with application-optimized contrasts using different flip-angle evolutions (3D-SPACE) sequence with variant flip-angle mode (VFAM) in the assessment of LM at 3-T MRI devices. METHODS: 3D-SPACE with VFAM images were obtained in 445 patients. LM visibility and integrity were scored as 0 (good), 1 (moderate), and 2 (poor) on these images for each parts (sellar, diencephalic, and mesencephalic) and overall of the membrane. RESULTS: According to the LM overall integrity scores, 11 % (48 cases) of the patients had perforated membrane. According to subsegmental integrity scores, sellar part was completely intact in 63 % of patients, diencephalic segment was completely intact in 60 % of the patients, and mesencephalic segment was completely intact in 95 % of the patients. Visibility scores of the third ventricle inferior wall were significantly higher in the patients with intact LM (p = 0.001). There was not any statistically significant relationship between LM pattern and overall integrity (p = 0.352). LM attachment sites could be detected easier in the patients who had better visibility of third ventricle inferior wall or intact LM (p < 0.001 for both). CONCLUSION: 3D-SPACE technique is a useful alternative for the evaluation of morphology, integrity, individual variations, topographic relationships, and visibility of LM since it has some advantages including lower SAR values, fewer artifacts, and high-resolution images.

Comparison of Early Onset Nasoalveolar Molding With Patients Who Presented for Molding Up to 1 Year of Age.

PURPOSE: To compare the effectiveness of nasoalveolar molding (NAM) in infants with complete unilateral cleft lip and palate presenting before and after 6 months of age and justify its use in older infants presenting for treatment. MATERIALS AND METHODS: The university NAM protocol was followed for 150 patients who were included in the study. NAM was performed by 1 month of age (group I, n = 50), at 1 to 6 months of age (group II, n = 50), and at 6 months to 1 year of age (group III, n = 50). Seven linear anthropometric measurements were compared using dentofacial models. RESULTS: Statistical analysis before and after NAM showed that group I had 83, 176, 69, and 142% improvement in intersegment distance, nasal height, nasal dome height, and columella height, respectively. Group II had 53, 44, 30, and 67% improvement. Group III had 45, 38, 28, and 62% improvement. CONCLUSION: Patients in all 3 groups showed improvement with the NAM protocol. Although patients who presented for treatment before 1 month of age benefited the most, those who presented at 6 months to 1 year of age benefited as much from NAM as those who presented at 1 to 6 months, thus validating its use in these patients.

Standardization of patellofemoral morphology in the pediatric knee.

BACKGROUND: Our understanding of osseous morphology and pathology of the patellofemoral joint continues to improve with the use of magnetic resonance imaging (MRI), but a paucity of data currently exists in the pediatric population. OBJECTIVE: We aim to formulate a reproducible means of quantitative assessment of patellofemoral morphology in children using MRI and to describe morphological changes based on sex and age. MATERIALS AND METHODS: We identified 414 children presenting between 2002 and 2014 who obtained a knee MRI to evaluate for knee pain or clinically suspected knee pathology. After application of inclusion criteria, 144 "normal" MRIs in 131 children (71 boys, 60 girls) were included in the analysis. The following MRI measurements were recorded: lateral trochlear inclination, trochlear facet asymmetry, trochlear depth, tibial tuberosity-trochlear groove distance, sulcus angle and patellar height ratio. To assess intraobserver reliability, measurements in 30 randomly selected children were repeated. Differences between patient age and sex were assessed using independent t-tests and adjusted regression analysis. RESULTS: All recorded measurements had strong to very strong inter- and intraobserver reliability: lateral trochlear inclination (0.91/0.82), trochlear facet asymmetry (0.81/0.83), trochlear depth (0.83/0.90), tibial tuberosity-trochlear groove distance (0.97/0.87), sulcus angle (0.84/0.78) and patellar height ratio (0.96/0.83). When age and sex were mutually adjusted, statistically significant differences between males and females were observed in trochlear depth (P = 0.0084) and patellar height ratio (P = 0.0035). However, statistically significant age differences were found on all measurements except for lateral trochlear inclination. As expected, mean measurement values approached adult norms throughout skeletal maturation suggestive of age-dependent patellofemoral maturation. CONCLUSION: Our data verify the development of patellofemoral morphology with advancing age. We found that six of the most commonly used patellofemoral measurements in adults can be accurately reproduced regardless of age.

Macrostomia: A Practical Guide for Plastic and Reconstructive Surgeons.

Macrostomia is a rare and debilitating congenital anomaly with incompletely understood etiopathogenesis. Despite the phenotypic variability in macrostomia, plastic surgeons should demonstrate competence in the diagnosis and management of this condition. The anatomy, embryology, classification, and clinical presentation of macrostomia are reviewed in this manuscript. A historical overview of surgical repair is presented that forms the basis for understanding modern techniques of repair. Finally, an effective method of macrostomia repair is presented along with review of 5-year results. It is our intent that this guide serve as a reference for plastic and reconstructive surgeons to accomplish safe, functional, and aesthetic macrostomia reconstruction.

Predictive Soft Tissue Airway Volume Analysis in Mandibular Distraction: Pushing The Envelope in Surgical Planning for Obstructive Sleep Apnea.

Three-dimensional computed tomography has been used in both preoperative planning of mandibular distraction osteogenesis and in the evaluation of postoperative resolution of tongue-based airway obstruction. The authors present a case report using software to predict postdistraction airway volume during virtual surgical planning (VSP) of mandibular distraction osteogenesis in a 7 year old. The predicted increase in airway volume derived from VSP was 33.57% (1716 mm(3) preoperatively to 2292 mm(3) postvirtual distraction). Based on the three-dimensional computed tomography, the actual airway volume increased to 2211 mm(3) postoperatively, a 28.85% increase.The implications of this advancing technology are far-reaching. An illustrative case is presented herein to demonstrate the efficacy of the airway prediction and its limitations. The authors believe that, with continued investigation, this novel approach may be a standard feature of all VSP sessions for the treatment of tongue-based airway obstruction.

New approach for the diagnosis of extractions with neural network machine learning.

INTRODUCTION: The decision to extract teeth for orthodontic treatment is important and difficult because it tends to be based on the practitioner's experiences. The purposes of this study were to construct an artificial intelligence expert system for the diagnosis of extractions using neural network machine learning and to evaluate the performance of this model. METHODS: The subjects included 156 patients. Input data consisted of 12 cephalometric variables and an additional 6 indexes. Output data consisted of 3 bits to divide the extraction patterns. Four neural network machine learning models for the diagnosis of extractions were constructed using a back-propagation algorithm and were evaluated. RESULTS: The success rates of the models were 93% for the diagnosis of extraction vs nonextraction and 84% for the detailed diagnosis of the extraction patterns. CONCLUSIONS: This study suggests that artificial intelligence expert systems with neural network machine learning could be useful in orthodontics. Improved performance was achieved by components such as proper selection of the input data, appropriate organization of the modeling, and preferable generalization.

Cephalometric configuration of the occlusal plane in patients with anterior open bite.

INTRODUCTION: This study was performed to investigate the cephalometric configuration of the occlusal plane in patients with anterior open bite. METHODS: Of 61 subjects with open bite (overbite ≥3.75 mm) who had been recruited consecutively from January 2006 to November 2013 and had no history of orthodontic treatment, 14 cephalometric landmarks indicating the incisal edge or the buccal or mesiobuccal cusp tips of each tooth were used for K-means clustering to classify the occlusal plane configuration. For the open-bite group and a control group with normal occlusion (n = 38), dentoalveolar height, which is the perpendicular distance of each tooth to the palatal or mandibular plane, was compared among the clusters and between the 2 groups. RESULTS: The open-bite subjects were divided into 2 clusters according to occlusal contact of the premolars: Y-form and V-form (with and without premolar contact, respectively). The normalized dentoalveolar heights of the 4 mandibular teeth (lateral incisor to second premolar) were significantly greater in the Y-form class than in the V-form class. The dentoalveolar heights of the 5 maxillary teeth (lateral incisor to first molar) were significantly greater in the open-bite group than in the control group. CONCLUSIONS: For anterior open-bite treatment, the cephalometric configuration of the occlusal plane should be considered based on the occlusal contacts of the premolars.

Facial morphology in children and adolescents with juvenile idiopathic arthritis and moderate to severe temporomandibular joint involvement.

INTRODUCTION: The aims of this study were to (1) assess lateral facial morphology in children and adolescents with juvenile idiopathic arthritis and moderate to severe temporomandibular joint (TMJ) involvement, (2) compare the lateral facial morphology of these subjects with and without TMJ involvement using cephalograms and 3-dimensional (3D) facial photographs, and (3) compare and correlate the results of the 3D photographic and cephalometric analyses. METHODS: Sixty patients with juvenile idiopathic arthritis were included and grouped as follows: group 1, juvenile idiopathic arthritis patients without TMJ involvement; group 2, juvenile idiopathic arthritis patients with moderate to severe unilateral TMJ involvement; and group 3, juvenile idiopathic arthritis patients with moderate to severe bilateral TMJ involvement. Lateral cephalograms were used to assess and compare lateral facial morphologies between the groups. Lateral projections of oriented 3D photographs were superimposed on the lateral cephalograms. The results of the lateral 3D photographic analysis were correlated with those of lateral cephalometric analysis. RESULTS: Group 3 showed the most severe growth disturbances, including more retrognathic mandible and retruded chin, steep occlusal and mandibular planes, and more hyperdivergent type (P <0.01). Group 2 showed similar growth disturbances, but to a lesser extent than did group 3. Photographic variables were significantly correlated with the soft tissue and skeletal variables of cephalograms (0.5 < r < 0.9; P <0.001). CONCLUSIONS: Subjects with juvenile idiopathic arthritis and unilateral or bilateral moderate to severe TMJ involvement had significant growth disturbances. Early intervention is recommended for these patients to prevent unfavorable facial development. Furthermore, with proper orientation, 3D photographs can be used as an alternative to conventional lateral cephalograms and 2-dimensional photographs.

Shape variation and covariation of upper and lower dental arches of an orthodontic population.

OBJECTIVES: This study aimed to quantify the patterns of shape variability and the extent and patterns of shape covariation between the upper and lower dental arch in an orthodontic population. METHODS: Dental casts of 133 white subjects (61 males, 72 females; ages 10.6-26.6) were scanned and digitized in three dimensions. Landmarks were placed on the incisal margins and on the cusps of canines, premolars, and molars. Geometric morphometric methods were applied (Procrustes superimposition and principal component analysis). Sexual dimorphism and allometry were evaluated with permutation tests and age-size and age-shape correlations were computed. Two-block partial least squares analysis was used to assess covariation of shape. RESULTS: The first four principal components represented shape patterns that are often encountered and recognized in clinical practice, accounting for 6-31 per cent of total variance. No shape sexual dimorphism was found, nevertheless, there was statistically significant size difference between males and females. Allometry was statistically significant, but low (upper: R(2) = 0.0528, P < 0.000, lower: R (2) = 0.0587, P < 0.000). Age and shape were weakly correlated (upper: R(2) = 0.0370, P = 0.0001, lower: R (2) = 0.0587, P = 0.0046). Upper and lower arches covaried significantly (RV coefficient: 33 per cent). The main pattern of covariation between the dental arches was arch width (80 per cent of total covariance); the second component related the maxillary canine vertical position to the mandibular canine labiolingual position (11 per cent of total covariance). LIMITATIONS: Results may not be applicable to the general population. Age range was wide and age-related findings are limited by the cross-sectional design. Aetiology of malocclusion was also not considered. CONCLUSIONS: Covariation patterns showed that the dental arches were integrated in width and depth. Integration in the vertical dimension was weak, mainly restricted to maxillary canine position.

Development of a digital impression procedure using photogrammetry for complete denture fabrication.

OBJECTIVES: We developed an innovative procedure for digitizing maxillary edentulous residual ridges with a photogrammetric system capable of estimating three-dimensional (3D) digital forms from multiple two-dimensional (2D) digital images. The aim of this study was to validate the effectiveness of the photogrammetric system. MATERIALS AND METHODS: Impressions of the maxillary residual ridges of five edentulous patients were taken with four kinds of procedures: three conventional impression procedures and the photogrammetric system. Plaster models were fabricated from conventional impressions and digitized with a 3D scanner. Two 3D forms out of four forms were superimposed with 3D inspection software, and differences were evaluated using a least squares best fit algorithm. RESULTS: The in vitro experiment suggested that better imaging conditions were in the horizontal range of ± 15 degrees and at a vertical angle of 45 degrees. The mean difference between the photogrammetric image (Form A) and the image taken from conventional preliminarily impression (Form C) was 0.52 ± 0.22 mm. The mean difference between the image taken of final impression through a special tray (Form B) and Form C was 0.26 ± 0.06 mm. The mean difference between the image taken from conventional final impression (Form D) and Form C was 0.25 ± 0.07 mm. The difference between Forms A and C was significantly larger than the differences between Forms B and C and between Forms D and C. CONCLUSION: The results of this study suggest that obtaining digital impressions of edentulous residual ridges using a photogrammetric system is feasible and available for clinical use.

Clarifying the mechanism of effect of the Bionator for treatment of maxillary protrusion: A percentile growth study.

AIM: The reported effects of Bionator treatment in patients with mandibular retrognathism are conflicting. This study evaluated the changes in craniofacial morphology resulting from treatment with a Bionator, based on measurement percentiles previously reported, to clarify the mechanism of the effect of this commonly used functional device. MATERIALS AND METHODS: Study Design: Retrospective. SETTING: A private orthodontic clinic. PARTICIPANTS: Forty-two children (mean age, 10.13 years) requiring treatment with a Bionator for Class II malocclusion (mandibular retrognathism). Children were randomly assigned to a Bionator group with or without an expansion screw. Measurements on lateral cephalometric radiographs were taken before and upon completion of Bionator treatment. All parameters measured were characterised according to the measurement percentiles previously reported. Each parameter was compared before and after treatment for all patients and for each treatment group using Wilcoxon's test. RESULTS: No significant differences in cranial length or mandibular body length were seen in any of the 3 groups, but anterior cranial base length and maxillary length were significantly decreased while mandibular ramus height and mandibular length were significantly increased after treatment in the Bionator with expansion screw group and in the all-patient group. CONCLUSIONS: The findings suggest that treatment with a Bionator with expansion screw during the growth and development stage results in increased mandible length and ramus height and inhibits the growth of the maxilla and anterior cranial base bone.

Changes in mandibular position in treated Class II division 2 malocclusions in growing and non-growing subjects.

OBJECTIVE: To determine changes in mandibular position after the treatment of patients presenting with Class II division 2 malocclusions and to test the null hypothesis that there is posterior displacement of the mandible in these patients, in comparison with a control group of Class II division 1 subjects. MATERIALS AND METHODS: The assessed data consisted of pre- and post-treatment cephalometric radiographs of 77 subjects identified with Class II division 1 and Class II division 2 malocclusions matched according to age, gender and treatment duration. All completed fixed appliance orthodontic treatment. The changes in the position of point B, Pogonion and Articulare were determined at the end of treatment by superimposing the cephalometric radiographs on Sella-Nasion line at Sella. Thirteen cephalometric parameters including the distance between Basion and Articular (Ba-Art) were measured at each stage. RESULTS: In both groups, SNB angle, SNPog angle and Ba-Art distance showed no statistically significant changes. Pogonion was displaced significantly in a forward and downward direction in the growing group, with no significant differences identified between Class I division 1 and Class II division 2 subjects. CONCLUSION: The null hypothesis that there is posterior displacement of the mandible in Class II division 2 malocclusion is rejected. The growth pattern of the mandible in both divisions of a Class I malocclusion after orthodontic treatment was found to be similar