Chihiro Tanikawa

Automated Cephalometry: System Performance Reliability Using Landmark-Dependent Criteria

OBJECTIVE The purpose of the present study was to evaluate reliability of a system that performs automatic recognition of anatomic landmarks and adjacent structures on lateral cephalograms using landmark-dependent criteria unique to each landmark. MATERIALS AND METHODS To evaluate the reliability of the system, the system was used to examine 65 lateral cephalograms. The area of each system-identified anatomic structure surrounding the landmark and the position of each system-identified landmark were compared with norms using confidence ellipses with alpha = .01, which were derived from the scattergrams of 100 estimates obtained according to the method reported by Baumrind and Frantz. When the system-identified area overlapped with the norm area, anatomic structure recognition was considered successful. In addition, when the system-identified point was located within the norm area, landmark identification was considered successful. Based on these judgment criteria, success rates were calculated for all landmarks. RESULTS The system successfully identified all specified anatomic structures in all the images and determined the positions of the landmarks with a mean success rate of 88% (range, 77%- 100%). CONCLUSION With the incorporation of the rational assessment criteria provided by confidence ellipses, the proposed system was confirmed to be reliable.

Lip Vermilion Profile Patterns and Corresponding Dentoskeletal Forms in Female Adults

OBJECTIVES To objectively classify shapes of the human lip vermilion in the lateral view, and to examine whether any morphologic characteristics of dentoskeletal patterns are specific to each classified lip profile pattern. MATERIALS AND METHODS Pretreatment, lateral facial photographs of 234 Japanese women were selected. Investigators with expert knowledge of the anatomic traits of the lip vermilion in the lateral view extracted from images of the face a 13-dimensional feature vector that represented lip vermilion profile shapes. The vector quantization technique was applied to the feature vectors to mathematically optimize the number of lip vermilion profile patterns. Dentoskeletal patterns that corresponded to each classified lip shape were compared statistically. RESULTS Seven patterns were found, and differences between patterns were notably maximized by the flatness of the anterior portion of the lip vermilion for the upper and lower lip, the position of the most protruded point of the lip vermilion, lip fissure inclination, and differences between the horizontal positions of the upper and lower lip vermilions. The dentoskeletal forms showed significant differences between classified lip vermilion profile patterns (P < .01). CONCLUSIONS (1) Vector quantization revealed that classifying lip vermilion profiles into seven representative patterns was optimal for maximizing differences in the configuration of the lip vermilion. (2) Lip vermilion profile shapes were found to be associated with horizontal lengths of the anterior cranial base, horizontal/vertical positions, inclination and length of the mandible, and horizontal positions and labio-lingual inclinations of the upper and lower incisors.

Asymmetric Anterior Distraction for Transversely Distorted Maxilla and Midfacial Anteroposterior Deficiency in a Patient With Cleft Lip/Palate: Two-Stage Surgical Approach

The present report describes a male patient with a unilateral cleft lip and palate who presented with midfacial anteroposterior and transverse deficiency. Correction involved a two-stage surgical-orthodontic approach: asymmetric anterior distraction of the segmented maxilla followed by two-jaw surgery (LeFort I and bilateral sagittal splitting ramus osteotomies). The present case demonstrates that the asymmetric elongation of the maxilla with anterior distraction is an effective way to correct a transversely distorted alveolar form and midfacial anteroposterior deficiency. Furthermore, successful tooth movement was demonstrated in the new bone created by distraction.

A Novel Method to Detect 3D Mandibular Changes Related to Soft-Diet Feeding

Craniofacial morphology varies among individuals, which is regulated by the interaction between genes and the environment. Soft-diet feeding is a widely-used experimental model for studying the association between the skeletal morphology and muscle-related loading on the bone. Traditionally, these studies have been based on linear and angular measurements provided on two-dimensional (2D) radiographs in the lateral view. However, 2D observation is based on simplification of the anatomical structures and cannot detect three-dimensional (3D) changes in detail. In this study, we newly developed a modified surface-based analysis with micro-3D computed tomography (CT) to examine and detect the 3D changes in the mandible associated with soft-diet feeding. Mice at 3 weeks of age were fed a powdered soft-diet (SD) or hard-diet (HD) of regular rodent pellets until 9 weeks of age. Micro-CT images were taken at age 9 weeks to reconstruct the anatomical architecture images. A computer-generated averaged mandible was superimposed to directly visualize the morphological phenotypes. Gross observation revealed the apparent changes at the posterior body of the mandible, the angular process and the condyle between HD and SD mice. Significant differences in the mapping indicated the regions of significant displacement in the SD mice over the averaged 3D image of the HD mice. This map revealed that vertical displacement was most evident in 3D changes. We also noted a combination of vertical, transverse and anteroposterior directions of displacement in the condylar growth, resulting in complicated shape changes in the whole condylar process in SD mice. In contrast, transverse displacement was more significant in the coronoid process. The map analysis further showed the significant outward displacement of the inner surface of the alveolar process, which consequently resulted in thinning of the alveolar process.

Automatic recognition of anatomic features on cephalograms of preadolescent children

OBJECTIVE To develop a system that automatically recognizes the dentoskeletal traits on cephalograms recorded for preadolescent children and to examine performance reliability. MATERIALS AND METHODS We obtained 859 lateral cephalograms and divided them into group P (400 films taken from orthodontic patients having permanent dentition) and group M (459 films taken from those having mixed dentition). Fifty-nine cephalograms in group M were reserved for system test, and the remaining cephalograms in groups M and P were used for system development. Using a previously reported method (Yagi and Shibata, 2003), systems S(M) and S(P+M) were developed with the knowledge generated from groups M and P+M (combined sample of groups M and P), respectively. The system S(P) that had been developed for cephalograms of permanent dentition in our previous report was also employed for comparison. To evaluate performance reliability, the systems examined the 59 reserved cephalograms. The areas of each system-identified anatomic structure surrounding the anatomic landmarks and the positions of each system-identified landmark were compared with the norms in the form of confidence ellipses. The success rates were calculated for S(P), S(M), and S(P+M). RESULTS The systems successfully identified all of the specified anatomic structures in all of the images. The systems S(P), S(M), and S(P+M) determined the landmark positions with a mean success rate of 69% (range, 38-98%), 82% (range, 50-100%), and 82% (range, 58-100%), respectively. CONCLUSIONS Systems S(M) and S(P+M) were confirmed to be accurate and reliable in recognizing the anatomic features on the cephalograms of preadolescent children.

Efficacy of Maxillary Anterior Segmental Distraction Osteogenesis in Patients With Cleft Lip and Palate

Objectives: To evaluate the effects of maxillary anterior segmental distraction osteogenesis (MASDO) in patients with cleft lip and palate (CLP) and to identify risk factors for increased relapse. Design: A retrospective study. Patients: Thirty-one Japanese patients with CLP who underwent MASDO were eligible for study inclusion. Main Outcome Measures: We evaluated lateral cephalograms obtained before (T1), at 3 months (T2), and at 1 year (T3) after MASDO, and measured changes from T1 to T2 (δT1T2), from T2 to T3 (δT2T3), and from T1 to T3 (δT1T3). We also evaluated the risk factors associated with an increased relapse. Results: Overall (δT1T3), MASDO improved retrusion of the maxilla. We measured a significant advancement (6.1 mm) of the anterior maxillary segment in δT1T2 (A-McNamara classification) and increases in the overjet and the SNA, ANB, and nasolabial angles. However, skeletal relapse was evident in δT2T3, and the median percentage of relapse was 10%. To explore the risk factors, we subdivided patients with a δT1T2 of >5 mm into 2 groups based on the percentage of relapse (>15% vs ≤15%). There were significant differences between these groups in the vertical positions of the anterior nasal spine and point A, and the angle formed by the SN and palatal planes (SNPP), suggestive of intraoperative counterclockwise rotation of the maxilla. Conclusions: MASDO is effective for correcting midfacial deficiencies, but counterclockwise rotation of the maxilla during surgery may cause relapse.

Dentofacial characteristics in a patient with Aarskog–Scott syndrome

Abstract Aarskog–Scott syndrome (ASS), also known as facio-digito-genital syndrome or faciogenital dysplasia, is a rare X-linked recessive disorder that mainly affects the musculoskeletal system of male individuals, and is related with mutations in FGD1. This study presents the case of a 9-year old Japanese boy who was diagnosed with ASS at the age of three. The patient presented to our orthodontic department with hypodontia, impacted teeth, and delayed eruption, with narrow upper arch and retrognathic mandibles. In the present report, we introduce the patient’s dentofacial characteristics.

Test-retest reliability of smile tasks using three-dimensional facial topography

OBJECTIVES To evaluate the test-retest reliability of three types of facial expression tasks using three-dimensional (3D) facial topography. MATERIALS AND METHODS Twelve adult volunteers were enrolled in this study. They were instructed to perform three different facial expression tasks: rest posture, posed smile, and maximum effort smile. Each task was recorded using a 3D image-capturing device on two separate occasions with an interval of 1 week between sessions. The images of two sessions were superimposed based on the forehead. For each participant and for each facial expression, a wire mesh fitting was conducted. This method generated 6,017 points on the wire mesh. Intraindividual reliability between sessions for each task was statistically tested by intraclass correlation coefficients (ICCs) and the 95% confidence interval minimal detectable change (MDC95). RESULTS The MDC95 for the repeated measures of the rest posture, posed smile, and maximum effort smile exhibited means of 0.8, 1.5, and 1.3 mm, respectively, on the z-axis. The ICCs ranged from substantial to almost perfect agreement for repeated measures for the rest posture and maximum effort smile (0.60 < ICC ≤ 1.00). The right corner of the mouth in the posed smile showed moderate agreement (0.40 < ICC ≤ 0.60). CONCLUSIONS The overall test-retest reliability of the maximum effort smile and rest posture showed substantial to almost perfect agreement, and this was clinically acceptable.

Improvement in three-dimensional facial configuration and jaw motion following surgical orthodontic treatment of a case with jaw deviation

Abstract The establishment of normal stomatognathic function and an acceptable facial appearance is considered an important treatment goal in orthodontics. The patient, who demonstrated posterior crossbites and jaw deviation, underwent treatment with a combined orthodontic-surgical approach utilizing maxillary transverse distraction osteogenesis, Le Fort I osteotomy, and bilateral SSRO. The smoothness of the masticatory jaw-closing movement and three-dimensional facial configuration were compared pre- and post-treatment. Correction of the posterior crossbites enabled the patient to perform smoother jaw-closing movements during chewing. Additionally, asymmetry in the morphology of the chin, cheek, and lips was reduced. These favorable changes in masticatory jaw movement kinematics and three-dimensional evaluation of the face justify the application of surgical-orthodontic treatment to improve jaw function and facial appearance.

Maxillary Expansion and Midline Correction by Asymmetric Transverse Distraction Osteogenesis in a Patient With Unilateral Cleft Lip/Palate: A Case Report

This case report presents the management of a female patient with unilateral cleft lip and palate presenting with skeletal Class III malocclusion and a narrow upper dental arch with a midline deviation. The treatment plan involved asymmetric transverse distraction osteogenesis of the maxilla to make the upper dental midline coincident with the facial midline. After the treatment, a good facial profile and a close intercuspation of teeth were achieved. Occlusion remained stable with normal overjet and overbite after 2-year retention.