Osteoclast activation and recruitment after application of orthodontic force
| Autor: | Min-Huey Chen, T. Peter Tsay, Ordean J. Oyen |
|---|---|
| Rok vydání: | 1999 |
| Předmět: |
Male
medicine.medical_specialty Time Factors Periodontal Membrane Dentistry Osteoclasts Orthodontics Bone Marrow Cells Cell Count Bone resorption Orthodontic Appliances Osteoclast Internal medicine medicine Maxilla Animals Femur Cobalt Radioisotopes Life span business.industry Dose-Response Relationship Radiation Rats Inbred F344 Rats Dose–response relationship medicine.anatomical_structure Endocrinology Tooth movement Bone marrow business Whole body Whole-Body Irradiation |
| Zdroj: | American journal of orthodontics and dentofacial orthopedics : official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics. 115(3) |
| ISSN: | 0889-5406 |
| Popis: | In this study, whole body radioactive cobalt 60 (Co60) irradiation was used in an orthodontic tooth movement model to investigate osteoclast activation and recruitment in adult rats. Seventy-five rats were divided into three groups and were irradiated with Co60 ranging from 10 to 26 Gray. An orthodontic appliance was fitted to each rat 12 days after initiation of irradiation. Identical appliances were fitted on an additional 25 unirradiated rats. Groups of rats were sacrificed 1 week before and on the day of appliance placement as well as 1, 2, 3, 4, or 5 weeks after appliance placement. Histologic sections from decalcified maxillary processes were prepared and osteoclasts were counted. Results showed that regardless of irradiation dosage, osteoclast number did not decrease during the first 3 weeks of orthodontic treatment; animals receiving lower (ie, 10 Gray) total irradiation actually showed a transient increase in the osteoclast number. In addition, regardless of dose in the irradiated rats, the total time osteoclasts were present in the periodontal membrane after orthodontic activation was reduced from 4 to 3 weeks. These findings lead us to hypothesize that osteoclasts involved in appliance-induced remodeling are initially from precursors in the periodontal membrane. During prolonged periods of orthodontic force application, replacement osteoclasts originate from bone marrow precursors. Although an orthodontic bone resorption cycle lasts 4 weeks, the life span of individual osteoclasts is limited to 9 to 10 days. The clinical significance of this finding remains to be elucidated. |
| Databáze: | OpenAIRE |
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