Masatoshi Chiba

Clinical study on eruption of permanent canines after secondary alveolar bone grafting

Objective Eruption of cleft-associated permanent canines was studied in 190 patients with unilateral cleft lip/palate and whose permanent canines had not erupted at the time of alveolar bone grafting. In 162 of these patients, width of bone defect was compared between patients who underwent surgical exposure of canines and those whose canines erupted naturally. Results Cleft-associated canines naturally erupted after bone grafting in 150 patients (78.9%) and required surgical exposure in 36 patients (18.9%). Cleft-associated canines had not yet erupted in two patients. Two patients were lost to follow-up. Nasal-side bone defects were significantly wider in patients who underwent surgical exposure of cleft-associated permanent canines than in those whose cleft-associated permanent canines erupted naturally. Conclusions The present results suggest that nasal-side cleft width is related to the need for surgical exposure of permanent canines in children with cleft lip/palate.

ENHANCEMENT OF ECTOPIC BONE FORMATION IN MICE WITH A DEFICIT IN FAS-MEDIATED APOPTOSIS

Bone tormation is under the control of cytokines as well as growth factors such as bone morphogenetlc protelns (BMP). This suggests the possibillity that osteogenesls might be modulated by factors which atso modulate the Immune system. To test whether Immune disorders In the host may influence bone formation, we studied BMP‐Induced bone formation In a C3H/HeJ strain of mice benring a mutant gene, the lymphoproliteration Qene (lpr) or the genemlbed lym‐phoprolifarative diseaee gene (gld), both of which are known to be a Fas delaion mutant and a Fas ligand mutant, respectively, and to Induce Immune disorders vla a deficit In Fas‐mediated apoptoak Crude BMP derived from bovine bone were injscted into the muscular tlasue In the femur of adult C3H/HaJ mice or C3H/HeJ mice bearing an lpr or gld gene. Quantltathre analysis of the resulting ectopic bone formation by X‐ray photography 2 weeks after infection revealed that the presence of either the Ipr or gld gene caused a bone mess dgnlficantly larger In dimension than that seen in the wiid type mice. Histologlcal examlnatlon also revealed the dmerent Influence between these mutant genes on the level of bone fofmatlon exhibited by hyallne cartilage and bone imbeculae. Based on these results, we discussed the possible mechanisms of the enhanced ectopic bone fotmation under the deficit In Fas‐medlated apoptosls.

Unilateral atrophy of the masticatory muscles and mandibular ramus due to pure trigeminal motor neuropathy: a case report

Pure trigeminal motor neuropathy is a very unusual disease that is characterized by trigeminal motor paralysis without trigeminal sensory disturbances and without the involvement of the other cranial nerves. We report a case of pure trigeminal motor neuropathy in a 70-year-old woman. The diagnosis was based on the results of clinical, electromyographic, and radiologic examinations. Only the motor branch of the left trigeminal nerve was damaged. Atrophy of the left-side masticatory muscles and jaw resulted in facial asymmetry. Magnetic resonance imaging (MRI) of the head and face did not detect any pathologic lesion, with the exception of atrophy and fatty infiltration of the muscles innervated by the left trigeminal motor nerve. The etiology of the patients pure trigeminal motor neuropathy was undetermined. Patients with suspected trigeminal motor neuropathy should undergo MRI of the head and face to evaluate the sequelae of denervation and to detect an intracranial or extracranial lesion.

Histological study of effect of bone morphogenetic protein derived from bovine tooth on periosteum in rats

SummaryIn this study, we examined histologically the effect of a bone morphogenetic protein (BMP) derived from bovine tooth on the periosteum. Supraperiosteal injection of crude BMP into femurs of Wistar rats (28 day old) resulted in periosteal cell proliferation with subsequent bone and cartilage formation. Moreover, proliferating periosteal cells migrated into injected BMP, and formed both cartilage and bone. These observations show that exogenous BMP stimulates mesenchymal cells of the periosteum to proliferate and differentiate into osteoblasts, and therefore BMP may be one of factors which are involved in differentiation of osteoblasts in the periosteum.

The relationship between bone marrow edema and bone changes in the mandibular condyle: A longitudinal study with MR imaging

Abstract Purpose Decreased signal intensity on T1- or proton-density weighted magnetic resonance imaging (MRI) and increased signal intensity on T2-weighted MRI in the bone marrow space are thought to reflect bone marrow edema (BME). The purpose of this study was to determine whether condyle BME is associated with condyle bone changes. Methods The subjects were 57 patients [65 temporomandibular joints (TMJs)] with TMJ disorders showing condyle BME on initial MRI. Condyle bone changes were compared between TMJs that showed a persistent BME pattern (group P, 43 TMJs in 40 patients) and those that showed normal bone marrow signals, indicating disappearance of BME (group D, 21 TMJs in 22 patients) on follow-up MRI. Results (1) In TMJs with a condyle with a normal shape on initial MRI, condyle bone changes were present in 53.9% of TMJs in group P in follow-up MRI, whereas the normally shaped condyle remained in all TMJs in group D. (2) In TMJs with condyle erosion on initial MRI, condyle erosion was also present in 35.7% of TMJs in group P in follow-up MRI, but had disappeared in all TMJs in group D. (3) In TMJs with condyle osteophytes on initial MRI, erosion was present in 22.2% of TMJs in group P, whereas osteophytes remained in all TMJs in group D. Conclusions The longitudinal study showed that condyle BME is associated with condyle bone changes and may cause condyle erosion.

Clinical Features of Idiopathic Parotid Pain Triggered by the First Bite in Japanese Patients with Type 2 Diabetes: A Case Study of Nine Patients

Objective First bite syndrome, characterized by pain in the parotid region after the first bite of each meal, predominantly develops in patients who have had head and neck surgery. Idiopathic parotid pain (IPP) that mimics first bite syndrome may present in patients without a history of surgery or evidence of an underlying tumor, but its clinical features are unclear. This study characterized the clinical characteristics of IPP in patients with diabetes. Study Design A retrospective case review involving the clinical findings and pain characteristics of nine patients with IPP and diabetes who presented to our department between 2013 and 2016. Results All the patients were men diagnosed with type 2 diabetes (median age, 43 years). IPP developed unilaterally in seven patients and bilaterally in two. The median intensity of the first bite pain was 8 on a numerical rating scale of 0–10. The trigger factor was gustatory stimuli, and the trigger area was the posterior section of the tongue. Postprandial pain occurred within 1–10 min after meals in six patients. Conclusions IPP may be considered a separate disorder, in which the pain characteristics are similar to those of first bite syndrome but the clinical features and pathophysiology are different.