Haruyo Miyazaki

An orthodontic study of temporomandibular joint disorders Part 1: Epidemiological research in Japanese 6–18 year olds

Malocclusion is considered one of the etiological factors of temporomandibular joint disorder (TMD). The purpose of this study was to investigate the prevalence of TMD and the relationship between TMD and the type of occlusion. The sample consisted of 7337 Japanese children, 6-18 years old, 3219 boys and 4118 girls. TMD symptoms were recorded as well as the type of occlusion in children with TMD. The prevalence of TMD overall was 12.2%. The prevalence increased with age and was slightly higher in girls (13%) than in boys 11.1%. This difference was not statistically significant. Joint sound as the only symptom was more common in younger subjects. TMD symptoms seemed more complicated with age when pain and abnormal jaw movement combined with sound. Joint sound was the most common symptom (89.3%), followed by the combination of sound and pain (2.2%). The incidence of other symptoms was under 1%. In subjects with TMD, 24.9% exhibited crowding, 20.1% had excessive overjet, 6.8% deep bite, 6.3% edge-to-edge bite, 5.6% anterior crossbite, 5.4% open bite, and 3.8% posterior crossbite. Morphologically normal occlusion was observed in 27.1%. In this study, many subjects with TMD had malocclusions. Early treatment may be important in the prevention of severe TMD. Although those with morphologically normal occlusions were included, a more detailed study concerning other causes of TMD is needed also.

Occlusal stability after extraction orthodontic therapy in adult and adolescent patients

In this study we compared the posttreatment stability of occlusion in adults and adolescents treated for crowding or maxillary protrusion with four-premolar extractions and edgewise mechanics at an average of more than 4 years out of treatment. The adolescent sample showed a significantly greater posttreatment increase in mandibular anterior crowding than the adult sample. Posttreatment overjet and overbite remained more stable in the adolescents. We noted a correlation between in-treatment expansion and posttreatment narrowing of mandibular intercanine width in the adults. Differences in postorthodontic occlusal changes were noted between the adult and adolescent samples.

A Survey of Orthodontic Treatment in Team Care for Patients With Syndromic Craniosynostosis in Japan

Objective: To understand the actual condition of orthodontic treatment in team care for patients with syndromic craniosynostosis (SCS) in Japan. Design: A nationwide collaborative survey. Setting: Twenty-four orthodontic clinics in Japan. Patients: A total of 246 patients with SCS. Main Outcome Measure: Treatment history was examined based on orthodontic records using common survey sheets. Results: Most patients first visited the orthodontic clinic in the deciduous or mixed dentition phase. Midface advancement was performed without visiting the orthodontic clinic in about a quarter of the patients, and more than a half of the patients underwent “surgery-first” midface advancement. First-phase orthodontic treatment was carried out in about a half of the patients, and maxillary expansion and protraction were performed. Tooth extraction was required in about two-thirds of patients, and the extraction of maxillary teeth was required in most patients. Tooth abnormalities were found in 37.8% of patients, and abnormalities of maxillary molars were frequently (58.3%) found in patients who had undergone midface surgery below the age of 6 years. Conclusions: Many patients underwent “surgery-first” midface advancement, and visiting the orthodontic clinic at least before advancement was considered desirable. First-phase orthodontic treatment should be performed considering the burden of care. Midface advancement below the age of 6 years had a high risk of injury to the maxillary molars. This survey is considered useful for improving orthodontic treatment in team care of patients with SCS.

Relationship between Orthodontic Treatment Plan and Goslon Yardstick Assessment in Japanese Patients with Unilateral Cleft Lip and Palate: One-stage vs. Two-stage Palatoplasty.

The present study targeted patients with unilateral cleft lip and palate (UCLP) undergoing either one - (Wardill technique) or two-stage palatoplasty (Perko technique). Correlations between Goslon Yardstick scores and orthodontic appliances used and whether an osteotomy was performed were investigated. No differences were observed between the two types of palatoplasty in terms of Goslon Yardstick scores. A palatal expander and protraction facemask were used in Phase I of orthodontic treatment. The palatal expander was selected for most patients with UCLP in Phase I, regardless of the surgical technique used. A protraction facemask was used in patients undergoing the Wardill procedure who had a Goslon Yardstick score placing them in Group 3 or 4. In contrast, a protraction facemask was used in patients undergoing the Perko procedure who had a Goslon Yardstick score placing them in Group 4. No significant differences were observed in the Goslon Yardstick scores yielded by either type of procedure. The Goslon Yardstick score in relation to whether an osteotomy was performed in Phase II as part of orthodontic treatment was determined, focusing on the relationship between that score and the palatoplasty method used. A protraction facemask was used in patients undergoing the Perko procedure, which eliminated the need for an osteotomy at a future date. However, a protraction facemask was also used in patients undergoing the Wardill option, and those patients were likely to require an osteotomy. In other words, the results suggest that the type of palatoplasty selected will determine the effectiveness of any orthodontic appliances used.

Occlusal status and craniofacial morphology in Down syndrome patients

1 Division of Orthodontics and Dentofacial Orthopedics, Ohu University Graduate School of Dentistry, Japan 2 Division of Orthodontics and Dentofacial Orthopedics, Department of Oral Growth and Development, Ohu University School of Dentistry, Japan 3 Division of Oral Physiology, Department of Oral Function and Molecular Biology, Ohu University School of Dentistry, Japan Orthod Waves–Jpn Ed 2013;72(1):1–9