A patient with skeletal Class Ⅲ malocclusion was treated in 2 phases during the early permanent dentition. In phase 1, maxillary protraction was combined with rapid palatal expansion; in phase 2, fixed appliances were placed. The results were good posttreatment, and, 1 year later, a favorable growth tendency could be observed. This report shows that treatment for a patient with skeletal Class Ⅲ malocclusion can be started in the early permanent dentition, with very good final results.

Environmental improvements can lead to greater size of skeletodental structures as the population comes closer to expressing its genetic growth potential. Such secular trends have been documented in many human settings, especially for increased stature and faster tempos of growth. The present study is based on 185 same-sex parent-offspring pairs of data for maximum buccolingual crown diameters of the permanent teeth from a cohort in Beijing, China, where parents experienced much of their development during and after World War Ⅱ with the deprivations of the changing regime. Their offspring enjoyed the relative stability of the established Communist system, where nutrition and stability were much improved. There were significant increases in buccolingual diameters of the premolars and molars in the offspring. Increase for premolars and molars was about 1%, but larger in females than males (1.6% vs. 0.5%). Opposite changes occurred in the incisors and canines (i.e., larger parental dimensions), but we contend that these are an age-related artifact brought on by greater passive eruption of older individuals' teeth that exposes a broader portion of the crown at the gingival margin. The secular trend in crown size coincides with other research in contemporary China, disclosing increases in body size and faster tempos of growth as health and nutrition continue to improve.

The purpose of the study was to analyze the effects of nonsurgical treatment on subjects with a severe skeletal Class Ⅲ deformity and to directly evaluate dental and facial profile changes. Eighteen patients with severe skeletal Class III malocclusions (5 males, 13 females), diagnosed as indication for orthognathic surgery, were included in the study. The average age was 13.7±2.5 years. All the cases were treated with Tip-Edge straight-wire technique or Begg light wire technique. Lateral cephalometric films taken at the beginning and at the end of treatment were analyzed with the Pancherz analysis and traditional cephalometric analysis. The arithmetic mean and standard deviation were calculated for each variable and paired t-test was performed. A mean reduction of 6.5mm in the overjet was noted (P<.001), with skeletal changes and dental changes contributing 20% and 80% to the overjet correction, respectively. The inclination of the upper incisors to the SN plane was increased 5.98 (P<.01). The inclination of the lower incisors to the mandibular plane was decreased 6.68 (P<.001). The difference between the distance of the upper lip and lower lip to Sn-Pg9 at the beginning of treatment changed from a negative value to a positive value with a significant difference (P<.001). Successful treatment effects can be obtained with nonsurgical therapy in severe skeletal Class Ⅲ malocclusions in the permanent dentition. A remarkable soft tissue change was noted after the treatment, and the concave facial profile changed to a straight profile (see two case reports).

The purpose of this study was to evaluate dentoskeletal and soft-tissue profile changes after extraction of lower second molars and treatment using the Tip-Edge technique in severe Class Ⅲ subjects. Thirteen patients with severe skeletal Class Ⅲ malocclusion (four males, nine females), diagnosed as requiring orthognathic surgery, but who rejected surgical therapy, were included in the study. The average age was 13.2±0.8 years. Lateral cephalometric films taken at the beginning and the end of treatment were analyzed using the Pancherz analysis and a traditional cephalometric analysis. The arithmetic mean and standard deviation were calculated for each variable. Paired ttest was performed to evaluate significant treatment change. After active treatment, dramatic overjet change was noted, with an average value of 5.5mm (P>001). Inclination of lower incisors was decreased 12.08 when measured to the mandibular plane (P>001). Inclination of upper incisors was increased by 2.18 to the SN plane (P<05). A negative value of the distance between upper and lower lip position to Sn-Pg9 at the beginning of treatment changed to a positive value (P<001). The results of this preliminary study suggest that success in the treatment of some severe Class Ⅲ deformity in the permanent dentition can be achieved with fixed appliances and extraction of lower second molars. A remarkable soft-tissue change was noted after the treatment, and concave facial profiles changed to straight profiles.

all-trans retinoic acid (atRA), the oxidative metabolite of vitamin A, is essential for normal embryonic development. Also, high levels of atRA are teratogenic in many species and can effectively induce cleft palate in the mouse. Most cleft palate resulted from the failed fusion of secondary palate shelves, and maintenance of the normal cell proliferation is important in this process of shelf growth. Toclarify the mechanism by which atRA causes cleft palate, we investigated the effect of atRA on proliferation activity and cell cycle distribution in mouse embryonic palatal mesenchymal (MEPM) cells. atRAinhibited the growth of MEPM cells by inducing apoptosis in a dose-dependent manner. atRA also caused aG1 block in the cell cycle with an increase in the proportion of cells in G0/G1 and a decrease in the proportion of cells in S phase, as determined by flow cytometry. We next investigated the effects of atRA on molecules that regulate the G1 to S phase transition. These studies demonstrated that atRA inhibited expression of cyclins D and Eat the protein level. Furthermore, atRA treatment reduced phosphorylated Rb and decreased cdk2 and cdk4 kinase activity. These data suggest that atRA had antiproliferative activity by modulating G1/S cell cycle regulators and by inhibition of Rbphosphorylation in MEPM cells, which might account for the pathogenesis of cleft palate induced by retinoic acid.