Congenital and postnatal factors inducing malocclusions in Japanese unilateral cleft lip and palate patients-determination using logistic regression analysis.

Objective : To assess the congenital and postnatal factors that affect degree of malocclusion in patients with unilateral cleft lip and palate using multivariate statistical analysis. Design : Retrospective study. Patients : All information on 135 subjects with unilateral cleft lip and palate was obtained from an oral examination and radiograph at the initial examination at an orthodontic clinic and from surgical records. Plaster models were taken before orthodontic treatment. The ages of the subjects ranged from 5 to 8 years with a mean age of 6.9 years. All primary surgeries for the patients were performed at a university hospital. Main Outcome Measures : The GOSLON Yardstick was used to assess the dental arch relationships (degree of malocclusion) in patients. Family history of Class III, degree of cleft, and congenitally missing upper lateral incisor on the cleft side were chosen as congenital factors inducing malocclusion. Presurgical orthopedic treatment, cheiloplasty, and palatoplasty were chosen as postnatal factors. Associations between various factors and dental arch relationships were assessed using logistic regression analysis. Results : According to adjusted odds ratios, family history of Class III is associated with a significantly worse dental arch relationship. Palatoplasty using push-back alone correlated to a dental arch relationship that was significantly worse than palatoplasty using push-back with a buccal flap. Conclusions : Multivariate analysis shows evidence that a positive family history of Class III and palatoplasty using push-back alone are associated with worse malocclusion of unilateral cleft lip and palate patients.

Three-dimensional craniomaxillary characteristics of the mouse with spontaneous malocclusion using micro-computed tomography.

The aim of this study was to clarify the morphological characteristics of craniomaxillary deviations in BALB/c-bm/bm mice with a spontaneous malocclusion (incisal transverse crossbite) using three-dimensional (3D) morphological measurements. Sixty female mice aged 13 and 25 weeks were divided into the following groups: control (BALB/c-+/+ mice, n = 20), norm (BALB/c-bm/bm mice with a normal occlusion, n = 20), and mal (BALB/c-bm/bm mice with a malocclusion, n = 20). Various points in the skull were selected and the distances between two points were measured using 3D micro-computed tomography (CT) images. Statistically significant differences in measurement values among the three groups were evaluated by one-way analysis of variance with a probability level of P < 0.05 considered statistically significant. At both ages, the lengths of almost all measurements in the norm and mal groups were significantly shorter than those in the control group. Comparison between the shifted and non-shifted sides in the mal group showed that significant lateral deviation at the maxilla and nasal bone had occurred. Using 3D micro-CT images, the results of this study quantitatively showed that the craniomaxillary complex of BALB/c-bm/bm mice was significantly smaller than that of BALB/c-+/+ mice and that BALB/c-bm/bm mice have a spontaneous transverse crossbite due to lateral deviation of the maxilla and nasal bone.

Relationship between degree of malocclusion and occlusal interference in mice that spontaneously develop anterior transverse crossbite.

INTRODUCTION: Mice with brachymorphism (bm) have defective chondrogenesis, including abnormal growth of the spheno-occipital synchondrosis. Malocclusion (anterior transverse crossbite) sometimes spontaneously occurs in inbred BALB/c-bm/bm mice, before the mandibular incisors erupt and make contact with the maxillary incisors. The aim of this study was to determine whether functional lateral loads to incisors promote anterior transverse crossbites in BALB/c-bm/bm mice. METHODS: BALB/c-bm/bm mice with normal occlusion (normal group), BALB/c-bm/bm mice with malocclusion in which the incisors were not cut (mal group), and BALB/c-bm/bm mice in which the incisors had been cut to eliminate the functional lateral load during continued growth (mal-cut group) were used. We examined the amounts of shift of the maxillary and mandibular incisors in each group using radiographic images. RESULTS: The amount of shift of the maxillary incisors in the mal group was significantly greater than that in normal group. The total amount of shift from the maxilla to the mandible in the mal group was significantly greater than in the normal and mal-cut groups. CONCLUSIONS: The results suggest that a continuous functional lateral load to the incisors is strongly related to promoting and worsening anterior transverse crossbite in BALB/c-bm/bm mice.

Growth and development of the cranial base in mice that spontaneously develop anterior transverse crossbite.

INTRODUCTION: Homozygous brachymorphic (bm/bm) mice are characterized by disproportionately short stature. Anterior transverse crossbite sometimes develops spontaneously in inbred BALB/c-bm/bm mice that produce undersulfated glycosaminoglycans. The reason for inferior growth of the craniofacial structures of BALB/c-bm/bm mice has not been clarified. We focused on the spheno-occipital synchondrosis (SOS)-the growth site of the cranium-and investigated the growth pattern in the SOS of the BALB/c-bm/bm mice. METHODS: The BALB/c-+/+ mice and BALB/c-bm/bm mice without malocclusion were used. Sagittal sections of the cranial bases were stained with hematoxylin and eosin, observed histologically, and used to measure the anteroposterior length and the percentage of active bone volume around the SOS. RESULTS: In the histologic study, compared with the cartilage in the BALB/c mice, a bipolar column was not seen in the cartilage of the SOS in the BALB/c-bm/bm mice. The histomorphometric study showed that the anteroposterior length of the posterior cranial base was significantly shorter and the percentage of active bone volume was significantly smaller in the BALB/c-bm/bm mice than in the BALB/c mice. CONCLUSIONS: The results suggested that normal endochondral growth is disturbed in the synchondrosis of the posterior base of the skull in BALB/c-bm/bm mice.