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Objectives: To test if leptin can be detected in the gingival crevicular fluid (GCF) around moving teeth, and to determine whether any changes occur during orthodontic tooth movement. Materials and Methods: An upper canine requiring distal movement served as the test tooth; the contralateral canine was used as a control tooth. The control tooth was included in the orthodontic appliance, but was not subjected to the orthodontic force. GCF sampling from the distal sites of the test and control teeth was done at baseline, 1 hour, 24 hours, and 168 hours. Results: Leptin concentrations of the test teeth decreased in a time-dependent manner. When compared with the baseline measurement, the decrease was significant at 168 hours (P , .05). Conclusions:The concentration of leptin in GCF is decreased by orthodontic tooth movement; the results of the present study also suggest that leptin may have been one of the mediators responsible for orthodontic tooth movement. (Angle Orthod. 2010;80:504-508.)

Objective: To test the null hypothesis that rapid maxillary expansion (RME) with a rigid bonded appliance has no effect on conductive hearing loss (CHL) in growing children. Materials and Methods: Fifteen growing subjects (mean age 13.43 Ϯ 0.86 years) who had narrow maxillary arches and CHL participated in this study. Three pure-tone audiometric and tympanometric records were taken from each subject. The first records were taken before RME (T1), the second after maxillary expansion (T2) (mean ϭ 0.83 months), and the third after retention (mean ϭ 6 months) and fixed appliance treatment (approximately 2 years) periods (T3). The data were analyzed by means of analysis of variance (ANOVA) and least significant difference (LSD) tests. Results: Hearing levels of the patients were improved and air-bone gaps decreased at a statistically significant level (P Ͻ .001) during active expansion (T2-T1) and the retention and fixed appliance treatment (T2-T3) periods. Middle ear volume increased in all observation periods. However, a statistically significant increase was observed only in the T2-T3 period. No significant change was observed in the static compliance value. Conclusions: The hypothesis is rejected. RME treatment has a positive and statistically significant effect on both improvements in hearing and normal function of the eustachian tube in patients having transverse maxillary deficiency and CHL.

Objective:To investigate whether patients with bilateral posterior crossbite have asymmetrically developed condyles. Materials and Methods:The study group consisted of 75 patients with bilateral posterior crossbite, and a control group of 75 subjects with normal occlusion. Condylar, ramal, and condylar plus ramal asymmetry values were computed for all of the subjects on orthopantomograms. Data were analyzed statistically by means of paired t-test and Student's t-test. Results: The patients with bilateral posterior crossbite had more asymmetrical condyles relative to the controls. However, there were no statistically significant differences in condylar, ramal, or condylar plus ramal heights between left and right sides in both the control and crossbite groups. Conclusion: Patients with bilateral posterior crossbite can have asymmetrical condyles and might be at risk for the development of future skeletal mandibular asymmetries.

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