Shuichi Morita

Vascular endothelial growth factor (VEGF) directly enhances osteoclastic bone resorption and survival of mature osteoclasts

In bone development and regeneration, angiogenesis and bone/cartilage resorption are essential processes and are closely associated with each other, suggesting a common mediator for these two biological events. To address this interrelationship, we examined the effect of vascular endothelial growth factor (VEGF), the most critical growth factor for angiogenesis, on osteoclastic bone‐resorbing activity in a culture of highly purified rabbit mature osteoclasts. VEGF caused a dose‐ and time‐dependent increase in the area of bone resorption pits excavated by the isolated osteoclasts, partially by enhancing the survival of the cells. Two distinct VEGF receptors, KDR/Flk‐1 and Flt‐1, were detectable in osteoclasts at the gene and protein levels, and VEGF induced tyrosine phosphorylation of proteins in osteoclasts. Thus, osteoclastic function and angiogenesis are up‐regulated by a common mediator such as VEGF.

A study on changes in caries risk and microbial flora with the placement of edgewise appliance

Abstract The aim of this study was to evaluate the changes of caries risk and oral microbial flora in the patients having edgewise appliance. Forty-two patients treated at the Orthodontic Clinic of Niigata University Hospital participated. Using a caries risk examination kit by Bio Medical Laboratory (BML, Tokyo), stimulated saliva test was performed to investigate the salivary flow rate, pH of saliva, buffer capacity, and the levels of lactobacilli. Modified Mitis–Salivarius–Bacitracin (MSB) agar plates were used to detect and count Streptococcus mutans and S. sobrinus. Furthermore, the members of commensal bacteria and transient bacteria in aerobic culture medium were examined in salivary level to investigate the alterations in oral microbial flora. The number of mutans streptococci and lactobacilli decreased after 1 month of treatment, and then increased to reach the initial level at 3 months. While the amount of plaque increased and saliva pH deteriorated after the onset of treatment, the salivary flow rate improved. The number of transient bacteria showed a tendency toward an increase. These results demonstrate that both caries risk and oral microbial flora balance possibly change with the placement of appliances. Therefore, caries risk test should be performed before and during orthodontic treatment to monitor alterations in intraoral environment of the orthodontic patients not to cause an iatrogenic caries.

Nonsurgical treatment of adult skeletal Class III malocclusion with crowding and missing four premolars corrected with extraction of mandibular first molars

Abstract An adult male patient was present with anterior cross bite. He was referred to Orthodontic Clinic of Niigata University Medical and Dental Hospital for recommendation of surgical orthodontic treatment by general practitioner. The patient was diagnosed as skeletal Class III with anterior crowding and missing four premolars. To correct anterior cross bite and crowding, surgical orthodontic treatment was considered, but the patient refused orthognathic surgery. We therefore determined that nonsurgical treatment with mandibular bilateral first molar extraction would be indicated. After treatment, suitable overjet, overbite and proper functional occlusion were attained with Class I molar relation. Active treatment was 34 months, and the treatment result remained stable 2 years and 4 months after debonding.

Availability of air powder polishing with crystalline cellulose as a prophylactic method for orthodontic patients with a multi-bracket appliance

Abstract The aim of this study was to comparatively evaluate the air powder polishing (APP) system with crystalline cellulose with the rubber cup and pumice (RCP) method as prophylactic methods in orthodontic patients. This study included two examinations. First, 58 orthodontic patients were randomized into the APP group or RCP group, and the changes in the colony counts of salivary mutans streptococci (MS) assessed before and after the prophylactic treatment were evaluated. Assessment of MS was conducted three times: immediately before the treatment (Test 1), immediately after the treatment (Test 2), and 1 month after the treatment (Test 3). The samples were inoculated on modified Mitis-Salivarius-Bactracin (MSB) agar plates. Under the microscope, the colonies were counted. In the second experiment, using a randomized split-mouth design, half the mouths of 8 patients were treated with APP and the contralateral side with RCP by three dentists, and then the time required for plaque removal was compared. Significant reduction in the colony count of MS in the saliva was observed in both the APP and RCP groups. However, the count of MS returned to the baseline level after 1 month in both groups. APP removed dental plaques in less time than RCP. APP with crystalline cellulose is a clinically available prophylaxis method for orthodontic patients, and appears to succeed in removing the plaque more quickly.

Clinical Statistical Study on Changes of TMJ Disorders in Patients with Surgical Orthodontic Treatment.

The symptoms of temporomandibular joint disorder (TMD) in 33 patients indicative for surgical orthodontic treatment (8 males and 25 females, mean age of 22.5 years) were evaluated before treatment, during presurgical orthodontic and after treatment respectively through the questionnaires and the study casts. The patients were divided into 18 mandibular prognathism, 4 mandibular retrusion, 15 asymmetry, and 4 open bite cases.1. There was a significant difference in incidence of TMD symptoms between before (81.8%) and after (48.5%) treatment in all the patients.2. Incidence of TMD disorders decreased from 86.7% to 60.0% in asymmetry, from 72.2% to 27.8%(p<0.05) in mandibular prognathism and from 50% to 25% in open bite from before to after treatment, while in mandibular retrusion it remained 75% before and after treatment.3. The incidence of joint noise was 100% in mandibular retrusion and 46.7% in asymmetry before and after treatment, while it decreased from 44.4% to 22.2%(p<0.05) in mandibular prognathism and from 25% to 0% in open bite. Joint noise showed various changes during presurgical orthodontics in each malocclusion.4. The incidence of difficulty in mouth opening remained 50% in mandibular retrusion before and after treatment, while it decreased from 26.7% to 6.7% in asymmetry and from 16.7% to 5.6% in mandibular prognathism from before to after treatment. The open bite patients did not show difficulty in mouth opening both before and after treatment. Incidence of difficulty of opening tended to decrease in asymmetry and mandibular prognathism during presurgical orthodontics, while it worsened in mandibular retrusion.5. Mean value of VAS (Visual analog scale) in mandibular retrusion, which was used as an indicator for pain of temporomandibular joint, decreased from 60.0±42.4 to 40.4±14.1 from before treatment to presurgical prthodontics, however, it increased and showed 65.0±21.2 after treatment. Although VAS in asymmetry and mandibular prognathism showed 27.5±23.3 and 30.0±22.9 before treatment, and 27.0±17.9 and 27.5±19.4 presurgical orthodontics respectively, it decreased to 6.7±2.9 and 5.0 after treatment respectively. Open bite did not show pain of TMJ before and after treatment.These results suggested that symptoms of TMD in asymmetry and mandibular prognathism tend to be improved by surgical orthodontic treatment, but there were some cases of mandibular retrusion that did not improve.

Comparison of Correction of Facial Asymmetry between Unilateral Sagittal Splitting Ramus Osteotomy Combined with Body Osteotomy and Bilateral Sagittal Splitting Ramus Osteotomies.

The purpose of this study was to clarify the correction of facial asymmetry through the orthognathic surgery. The subjects were operated by bilateral sagittal splitting ramus osteotomies (SSRO group) and the unilateral sagittal splitting ramus osteotomy combined with the body ostectomy (SSRO-BODY group). Skeletal and soft tissue outlines were obtained from the frontal cephalogram before and after surgery. These outlines were normalized, and changes of those outlines in the two groups were compared with each other.As for soft tissue outline, asymmetry of both groups were corrected much better after surgery.In skeletal outline of the SSRO group, there were significant changes in the region of bilateral mandibular angle after surgery, but change of the outline was a little on the deviation side. In the SSRO-BODY group, however, outline in regions of bilateral mandibular angle and ramus on the deviation side changed significantly after surgery. Facial asymmetry seemed to be corrected much more in the SSRO-BODY group than the SSRO group.