A Histological Evaluation of Functional Recovery after Detachment of Masseter Muscle in Rats

Research Project

Project/Area Number	08457576
Research Category	Grant-in-Aid for Scientific Research (B)
Allocation Type	Single-year Grants
Section	一般
Research Field	矯正・小児・社会系歯学
Research Institution	OHU University
Principal Investigator	UMEMURA Sachio OHU University, Orthodontics, Lecurer, 歯学部, 講師 (80151934)
Project Period (FY)	1996 – 1998
Project Status	Completed (Fiscal Year 1998)
Budget Amount *help	¥800,000 (Direct Cost: ¥800,000) Fiscal Year 1998: ¥400,000 (Direct Cost: ¥400,000) Fiscal Year 1997: ¥400,000 (Direct Cost: ¥400,000)
Keywords	Detachment masseter muscle / Orthognathic Surgery / muscular atrophy / functional recovery of muscle / rats / 筋機能回復
Research Abstract	In order to observe the restored state of muscle after wasseteric ablation following surgical orthodontics treatment a masseteric ablation was experimentally induced in wistar Crj rats 120 days postpartum and the results were as folluws. 1. On the operated side as compared with the controled side atrophy of muscular fibers was evident one week after operation though there was no pathological finding such as necrosed fiber. 2. On the control side the muscle fibers were surrounded by supportive tissue with retained normal construction, morphology and arrangement as wel as clear outline straition one week. 3. The diameter of masseter muscle five week after operation averaged 57.5um on the operated side, which was smaller than 64.5 um on the control side with significant difference at a risk rate of 1%. 4. The diameter of masseter muscle six weeks after operation averaged 58.2um on the operated side, which was smaller than 62.0 urn on the control side with significant difference at a risk rate of 1%. 5. The diameter of masseter muscle seven weeks after operation averaged 52.5um on the operated side, which was smaller than 60.8 um on the control side with significant difference at a risk rate of 1%. 6. The diameter of masseter muscle eight weeks after operation averaged 52.2um on the operated side, which was smaller than 70.4 urn on the control side with significant difference at a risk rate of 1%. These results suggested that muscular restoration is not attained is by masseteric ablation follwing surgical orthodontic treatment in the clincal field for one two year after operation requiring a relatively long recovery of the muscle be done clinical after opration.