title: Experimental comparison between tractional and compressive stress on temporomandibular joint.
abstract: OBJECTIVE
  We experimentally compared the effects of compressive and tractional mechanical stress on the temporomandibular joint (TMJ) of rabbits to assess the etiology of progressive condylar resorption.
  
  
  METHODS
  We performed a cortical osteotomy using custom-made devices that were lengthened by 0.25 mm every 12 h for 1 week after surgery. During this time, the rabbit TMJ was under compressive or tractional mechanical stress. The samples in each group were examined using micro-computed tomography and histological staining.
  
  
  RESULTS
  Scores for the area of bone resorption were higher in the compressive group than in the tractional group. Moreover, scores for the depth of bone resorption were higher in the compressive group than those in the tractional group. We observed a significantly higher prevalence of resorption in the subcondylar bone in the compressive group than in the tractional group. There were substantially more cells that were positive for tartrate-resistant acid phosphatase in the compressive group than in the control and tractional groups.
  
  
  CONCLUSIONS
  The outcomes here suggest that excessive mechanical stress, particularly compressive mechanical stress, may significantly affect morphological bone change findings in the TMJ.
authors.affiliation: Division of Oral and Maxillofacial Surgery, Department of Oral Medicine and Surgery, Tohoku University Graduate School of Dentistry, Sendai, Miyagi, Japan.
authors.forename: S
authors.identifier: http://orcid.org/0000-0001-5885-9529
authors.initials: S
authors.lastname: Nogami
authors.affiliation: Division of Oral and Maxillofacial Surgery, Department of Oral Medicine and Surgery, Tohoku University Graduate School of Dentistry, Sendai, Miyagi, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Yamauchi
authors.affiliation: Division of Oral Pathology, Department of Oral Medicine and Surgery, Tohoku University Graduate School of Dentistry, Sendai, Miyagi, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Shimizu
authors.affiliation: Division of Oral and Maxillofacial Surgery, Department of Oral Medicine and Surgery, Tohoku University Graduate School of Dentistry, Sendai, Miyagi, Japan.
authors.forename: B
authors.initials: B
authors.lastname: Hirayama
authors.affiliation: Division of Oral Diagnosis, Department of Oral Medicine and Surgery, Tohoku University Graduate School of Dentistry, Sendai, Miyagi, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Kumasaka
authors.affiliation: Division of Oral Diagnosis, Department of Oral Medicine and Surgery, Tohoku University Graduate School of Dentistry, Sendai, Miyagi, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Iikubo
authors.affiliation: Division of Oral Pathology, Department of Oral Medicine and Surgery, Tohoku University Graduate School of Dentistry, Sendai, Miyagi, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Kumamoto
authors.affiliation: Division of Oral and Maxillofacial Surgery, Department of Oral Medicine and Surgery, Tohoku University Graduate School of Dentistry, Sendai, Miyagi, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Takahashi
mesh_terms: D000818:Animals; D001862:Bone Resorption / Q000000981:diagnostic imaging / Q000209:etiology*; D008335:Mandibular Condyle / Q000000981:diagnostic imaging / Q000503:physiopathology; D011312:Pressure / Q000009:adverse effects*; D011817:Rabbits; D013314:Stress, Mechanical; D013704:Temporomandibular Joint / Q000000981:diagnostic imaging / Q000503:physiopathology; D014143:Traction / Q000009:adverse effects*; D055114:X-Ray Microtomography
keywords: compressive mechanical stress; condylar resorption; rabbit; temporomandibular joint; tractional mechanical stress