Toshiko Sekiya

Elimination of transverse dental compensation is critical for treatment of patients with severe facial asymmetry

This case report describes the importance of eliminating transverse dental compensation during preoperative orthodontic treatment for a patient with severe facial asymmetry. The patient, a 17-year-old Japanese woman, had severe facial asymmetry involving the maxilla and the mandible, and extreme transverse dental compensation of the anterior and posterior teeth in both arches. Therefore, the main treatment objectives were elimination of the transverse dental compensation by orthodontic treatment and correction of the morphology of the maxilla and the mandible by orthognathic surgery. The preoperative orthodontic treatment resulted in sufficient elimination of the transverse dental compensation and movement of the teeth into their proper positions so that basal bone firmly supported them. LeFort I osteotomy and sagittal split ramus osteotomy were performed to correct the skeletal morphology. Facial asymmetry was dramatically improved, and a favorable occlusion was obtained. At 1 year 8 months after the surgical orthodontic treatment, the facial symmetry and occlusion remained favorable. The results suggest that sufficient elimination of transverse dental compensation in the maxillary and mandibular arches during preoperative orthodontic treatment is requisite for successful treatment of severe facial asymmetry.

Cranial-base morphology in adults with skeletal Class III malocclusion.

INTRODUCTION The objectives of this study were to clarify the characteristics of cranial-base morphology in adults with skeletal Class III malocclusion and investigate factors relating to the establishment of a skeletal Class III malocclusion. METHODS Initial lateral cephalograms of women were examined. Subjects with an ANB angle of 0° to 4°, normal overjet and overbite, and a Class I molar relationship were classified as Class I (n = 86). Those with an ANB angle less than -1°, a Wits appraisal less than 2 mm, a negative overjet, and a Class III molar relationship were the Class III group (n = 86) in this study. Angular, linear, and coordinate measurements were made. Multivariate analysis of variance and the Student t test were used to analyze significant differences between the 2 groups. Discriminant analysis, logistic regression analysis, and decision analysis were used to identify which cranial-base and maxillomandibular variables influenced the establishment of a skeletal Class III malocclusion. RESULTS The Class III group had smaller values for NSBa, SeSBa, FH-SSe, and FH-SBa. Sphenoidale and basion were more inferior and anterior than those of the Class I group. There was no difference in the anterior and posterior cranial-base lengths between the groups. Greater mandibular length was the first major characteristic in the Class III group, followed by smaller values for SeSBa and NSBa. CONCLUSIONS Cranial-base morphology in adults with a skeletal Class III malocclusion is different from that in a skeletal Class I malocclusion. Smaller cranial-base angles, steeper posterior cranial bases, more inferiorly positioned sphenoidale, and more anteriorly positioned basion are major characteristics of skeletal Class III malocclusions. These characteristics play important roles in the establishment of a skeletal Class III malocclusion.

Reconstruction of a collapsed dental arch in a patient with severe periodontitis.

This case report describes the significance of orthodontic treatment in reconstruction of a collapsed dental arch and a malocclusion associated with severe periodontitis. A Japanese man (age, 40 years 7 months) had an anterior crossbite, a collapsed occlusion, and severe periodontitis. Orthodontic treatment included the following steps: (1) correction of the anterior crossbite, labial movement of the maxillary incisors, and intrusion and retraction of the mandibular incisors; (2) correction of the posterior crossbite on the left side, buccal movement of the maxillary left canine and first premolars, and intrusion and retraction of the mandibular first premolar into the space of the mandibular left canine; (3) correction of the crowding of the mandibular right buccal segment and alignment of the teeth after extraction of the mandibular right first molar with a periapical lesion; and (4) improvement of the occlusion, with reconstruction of an acceptable occlusion. When combined with restorative and prosthodontic treatment, a fairly good occlusion was obtained. Reevaluation of the treatment after 11 years showed that the occlusion and periodontal condition were maintained well without deepening of the pockets and further bone loss. Orthodontic treatment with a systematic approach helped to recover the occlusion and prevented the recurrence of periodontitis by acquiring a good oral environment and motivating the patient to maintain oral health.

Severe lateral open bite caused by multiple ankylosed teeth: A case report

Multiple ankylosed teeth in a dental arch is rare and occasionally causes severe open bite. This article describes a case of severe lateral open bite caused by multiple ankylosed teeth. The patient was a 31-year-old female and her chief complaint was inadequate masticatory function on the right side. All the maxillary right teeth exhibited infraocclusion. The maxillary right first molar showed partial impaction and the maxillary and mandibular right second molars were completely impacted, although on the left side these teeth had fully erupted. CT images revealed unclear periodontal space between the alveolar bone and roots of the maxillary teeth from the incisor to the first molar on the right. To improve the masticatory function, a removable prosthetic appliance was applied to the maxillary arch. Prosthetic rehabilitation may be an effective alternative to surgical procedures such as distraction osteogenesis of the alveolar bone and subluxation of the ankylosed teeth.

Defining the location of the dental midline is critical for oral esthetics in camouflage orthodontic treatment of facial asymmetry

When considering camouflage orthodontic treatment of a malocclusion associated with significant facial asymmetry, it is important to define the location of the dental midline. The patient, a 19-year-old Japanese woman, had an anterior open bite and a dental midline discrepancy associated with facial asymmetry. A nonsurgical treatment plan was considered. The main treatment objective was to correct the anterior open bite and the dental midlines in both arches. The dental midline discrepancy was eliminated, and proper overjet and overbite were achieved. Although the facial asymmetry remained, oral esthetics dramatically improved and a favorable occlusion was obtained. The results suggest that appropriately defining the location of the dental midline is critical for successful camouflage treatment of facial asymmetry.

Influence of posterior cranial base growth on the therapeutic effect of bite jumping appliance

Abstract Objective Aim of this study was to examine influence of posterior cranial base (PCB) growth on the effect of bite jumping appliances in skeletal Class II malocclusion. Material and methods Cephalograms at pretreatment (T1) and completion of functional therapy (T2) of twenty-eight skeletal Class II Japanese patients treated with bite jumping appliances were used in this study. All subjects were divided into two groups according to reduction of ANB angle and establishment of Angle Class I molar relationship: improved and non- improved groups. Results There was a wide range of individual differences in the PCB growth during the treatment period. The changes of Ba(x) and Ba(y) in the PCB growth were highly correlated to the positional changes of Ar respectively, though there were no correlations between Ba(x) and Ba(y), and Ar(x) and Ar(y). The change of Ba(x) between T1 and T2 in improved group was significantly less than that in non-improved group. The change of Ar(x) in the improved group was significant less than that in the non-improved group. Discriminant analysis demonstrated that the change of Ar(x) was the most important factor that influenced the ANB angle (intermaxillary relationship). Conclusion The results in this study suggest that PCB growth, especially anteroposterior growth evidently influences the effect of bite jumping appliance.