Effects of CO2 laser irradiation of the gingiva during tooth movement.

Patients often feel pain or discomfort in response to orthodontic force. It was hypothesized that CO(2) laser irradiation may reduce the early responses to nociceptive stimuli during tooth movement. The distribution of Fos-immunoreactive (Fos-IR) neurons in the medullary dorsal horn of rats was evaluated. Two hrs after tooth movement, Fos-IR neurons in the ipsilateral part of the medullary dorsal horn increased significantly. CO(2) laser irradiation to the gingiva just after tooth movement caused a significant decrease of Fos-IR neurons. PGP 9.5- and CGRP-positive nerve fibers were observed in the PDL of all study groups. The maximum temperature below the mucosa during CO(2) laser irradiation was less than 40 degrees C. It was suggested that CO(2) laser irradiation reduced the early responses to nociceptive stimuli during tooth movement and might not have adverse effects on periodontal tissue.

Deglutitive movement of the tongue under local anesthesia.

The purpose of the present study was to investigate whether or not sensory input from the tongue affects deglutitive tongue movement. Subjects were seven healthy volunteers with anesthetic applied to the surface of the tongue (surface group) and seven healthy volunteers with the lingual nerve blocked by anesthetic (blocked group). We established six stages in deglutition and analyzed deglutitive tongue movement and the time between the respective stages by cineradiography before and after anesthesia. After anesthesia in both surface and blocked groups, deglutitive tongue movement slowed and bolus movement was delayed. The deglutitive tongue tip retreated in the blocked group. These results suggest that delay of tongue movement by anesthesia causes weak bolus propulsion and that deglutitive tongue tip position is affected by sensory deprivation of the tongue or the region innervated by the inferior alveolar nerve.

Subcutaneous inflammatory reaction to a synthetic auditory ossicle (Bioceram) in rats.

Cellular response and inflammatory reaction to synthetic auditory ossicle (Bioceram) made from aluminium oxide are investigated. Local inflammatory effects are important in wound healing and in determining biocompatibility of an implant, necessitating the study of biologic effects of implants, especially inflammation and fibrous capsule formation. Bioceram discs were implanted subcutaneously in the interscapular region of rats for various periods of time, ranging from 1 day to 300 days. Histological sections 6 microns thick were stained with haematoxylin and eosin. Cell types around the implants were examined quantitatively by light microscopy. Inflammatory cell reaction to Bioceram decreased rapidly within 14 days, similar to the reaction in control groups. From 30 days to 300 days after implantation, there was continuous reduction to very low levels for macrophages and lymphocytes, but fibrous connective tissue capsule around implants matured. Preliminary results suggest that Bioceram is a satisfactory biocompatible material for reconstructive surgery from the viewpoint of cellular response. We also briefly discuss the different tissue responses in light of our previous study on hydroxyapatite (Apaceram).

Orthodontic treatment of a patient with hypophosphatemic vitamin D-resistant rickets.

Hypophosphatemic vitamin D-resistant rickets, when developed later in life, is less severe and may not be characterized by rickets or other osseous deformities. A Japanese girl, age nine years and one month, was first seen in the Dental Hospital of Osaka University, complaining of the crowding of the maxillary teeth. At one year of age, the patient was admitted to Osaka University Hospital for her leg deformities. Although the patient has been administered 4 micrograms 1 alpha/-hydroxyvitamin D3 and 1.0 g phosphorous daily, the serum phosphate has been low and never reached normal level. This case was a Class II division 2 malocclusion with severe anterior crowding and retarded mandibular growth. We treated her with a functional appliance (elastic open activator), followed by the extraction of four premolars and the use of an edgewise appliance. No unfavorable root resorption or bone defect occurred. Good occlusion was achieved and the facial features were pleasing.

Effects of salvia miltiorrhiza bunge (SMB) on MC3T3-E1 cells.

In previous research, we found that the Salvia Miltiorrhiza Bunge (SMB), a traditional Chinese medicinal herb, accelerates orthodontic tooth movement. In the present study, to characterize the actions of SMB on bone remodeling, we investigated the effect of SMB on DNA synthesis and alkaline phosphatase activity of murine osteoblast like cell-clone, MC3T3-E1 cells in vitro. Treatment of the cells with SMB for 72 hours caused significant increase in ALPase activity. It was found that SMB increased ALPase activity in a dose-dependent manner, and up to maximum at the concentration of 5.0 mg/ml. At that concentration, ALPase activity was about 135% greater than that of control. SMB at 5.0 mg/ml significantly stimulated ALPase activity of the cells in multilayer on day 8 or calcification stage on day 16, but inhibited it in the sparse stage on day 2 or subconfluency stage on day 4. SMB had no effect on DNA synthesis in any stage of culture. ALPase activity significantly increased at 48 hours and was up to 300% greater than that of control activity at 96 hours. These findings suggest that SMB directly stimulates ALPase activity of MC3T3-E1 cells in multilayer stage or calcification stage without any effect on proliferation. Locally administrated SMB may affect the differentiation of osteoblasts in vivo.