S. Akimoto

Comparison of Japanese and European overbite depth indicator and antero-posterior dysplasia indicator values

This study evaluated cephalometric differences between 113 Japanese (43 males and 70 females, aged 14.1 ± 5 years) and 106 European subjects (36 males and 70 females, aged 13.5 ± 7.3 years) using two compound angular measurements and their single components: the overbite depth indicator (ODI) for the assessment of vertical skeletal relationships and the antero-posterior dysplasia indicator (APDI) for an evaluation of sagittal dysgnathia. Both populations were assigned to groups representing Angle Classes I, II, and III, and an anterior open bite (AOB) group. Two sample t- and Wilcoxon signed-ranks tests were performed (P < 0.05). The ODI values showed no statistically significant differences between the Japanese and European samples. The Japanese sample showed a significantly smaller APDI but only in the Class II group. In the Japanese Class II and III subjects, the malocclusion patterns were more pronounced than those in the Caucasian sample (overbite, overjet, and APDI).

Comparison of Brain Activation via Tooth Stimulation

The aim of this study was to evaluate the sensation of each tooth type at the cortical level. The tactical sensation from teeth plays an important role in controlling the masticatory system. However, the role of each tooth type has not been determined. Functional near-infrared spectroscopy (fNIRS) was used to detect changes in cerebral blood flow in the somatosensory cortex of 12 healthy volunteers. Painless vibrotactile stimuli were applied to 8 teeth (left maxillary and mandibular incisors, canines, 1st premolars, or 1st molars). The somatosensory cortex was activated during stimulation of all teeth. A comparison of cortical activation revealed significantly greater activation during stimulation of the maxillary and mandibular first molars. However, no significant differences were seen between any other teeth. These results indicate that the first molar is the most sensitive tooth type at the cortical level, and provide basic data on the relationship between input from individual tooth type and brain activation. These data could be useful for understanding the neural mechanisms of individual tooth types.

Ameliorating effects of Juzentaihoto on restraint stress and P. gingivalis-induced alveolar bone loss.

OBJECTIVE Juzentaihoto (JTX) is a traditional Japanese medicine that consists of 10 herbs. The purpose of this study was to evaluate the efficacy of multi-herbal medicine JTX as a preventive and therapeutic drug for periodontal bone resorption and for reducing restraint stress. MATERIALS AND METHODS Porphyromonas gingivalis ATCC 33277 was used for testing the antibacterial activity of JTX and a rat experimental periodontitis model. To evaluate the effect of JTX against P. gingivalis infection, we determined the differences in alveolar bone loss among experimental groups. The concentrations of adrenocorticotropic hormones were measured as stress markers, and atrophy of the thymus and spleen was assessed. RESULTS JTX had antibacterial activity against P. gingivalis ATCC 33277. JTX treatment of mouse bone marrow cells at a concentration of 0.1 μg/ml significantly inhibited osteoclast formation. Administration of JTX to rats with P. gingivalis infection and restraint stress significantly reduced alveolar bone loss compared with the case with just the combination of P. gingivalis infection and restraint stress. In the restrained groups, stress markers were elevated, and the thymus and spleen were atrophied. The groups with administration of JTX showed not only inhibition of the decrease of weight but also normalization of corticosterone and cortisol values. CONCLUSION JTX effectively inhibited restraint stress and osteoclastogenesis. It appears that the effects of JTX inhibit the destruction of periodontal tissue by suppressing stress. Our study demonstrated that JTX affects the correlation between restraint stress and periodontitis.

Vertical facial height and its correlation with facial width and depth: Three dimensional cone beam computed tomography evaluation based on dry skulls

IntroductionThe aim of the present study was to evaluate how vertical facial height correlates with mandibular plane angle, facial width and depth from a three dimensional (3D) viewing angle.MethodsIn this study 3D cephalometric landmarks were identified and measurements from 43 randomly selected cone beam computed tomography (CBCT) images of dry skulls from the Weisbach collection of Vienna Natural History Museum were analyzed. Pearson correlation coefficients of facial height measurements and mandibular plane angle and the correlation coefficients of height-width and height-depth were calculated, respectively.ResultsThe mandibular plane angle (MP-SN) significantly correlated with ramus height (Co-Go) and posterior facial height (PFH) but not with anterior lower face height (ALFH) or anterior total face height (ATFH). The ALFH and ATFH showed significant correlation with anterior cranial base length (S-N), whereas PFH showed significant correlation with the mandible (S-B) and maxilla (S-A) anteroposterior position.ConclusionsHigh or low mandibular plane angle might not necessarily be accompanied by long or short anterior face height, respectively. The PFH rather than AFH is assumed to play a key role in the vertical facial type whereas AFH seems to undergo relatively intrinsic growth.