Stress change on the temporomandibular joint in mandibular prognathism subjects with asymmetry after orthognathic surgery
| Autor: | Kiyomasa Nakagawa, Koichiro Ueki, Etsuhide Yamamoto, Kohei Marukawa, Norio Takeuchi |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2010 |
| Předmět: |
Adult
Male Models Anatomic Adolescent Cephalometry medicine.medical_treatment Orthognathic surgery Dentistry Orthodontics Mandible Condyle Mandibular second molar Young Adult Dental Occlusion Balanced medicine Humans Prognathism Displacement (orthopedic surgery) Range of Motion Articular Mathematics Temporomandibular Joint Orthognathic Surgical Procedures business.industry Temporomandibular Joint Disorders medicine.disease Adaptation Physiological Temporomandibular joint Bite force quotient medicine.anatomical_structure Facial Asymmetry Jaw Relation Record Female Stress Mechanical business |
| Zdroj: | European Journal of Orthodontics. 32(5):522-529 |
| ISSN: | 0141-5387 |
| Popis: | 金沢大学医薬保健研究域医学系 The purpose of this study was to evaluate changes in stress on the temporomandibular joint (TMJ) in 80 Japanese subjects (21 males and 59 females, mean age 23.7 years) with mandibular prognathism, with and without asymmetry after orthognathic surgery using the rigid bodies spring model (RBSM). The asymmetric group consisted of 40 subjects whose Mx-Md midline was more than 3 degrees. The remaining 40 subjects formed the symmetric group.The geometry of the stress analysis model was based on frontal cephalograms of the subjects. Menton (Me), the centre point of occlusal force on a line connecting the bilateral buccal cusps of the second molars, and the most lateral, superior, and medial points on the condyle were plotted on a computer display and stress on the condyle was calculated with the two-dimensional RBSM program, Fortran. The degree (force partition) of the resultant force, the direction (angulation), and the displacement (X, Y) of each condyle were calculated and the horizontal displacement (u), the vertical displacement (v), and rotation displacement (θ) of the mandibular body at Me were calculated pre- and post-operatively. The data was analysed using paired and unpaired t-tests.For the vertical (v) and rotational (θ) displacement, the post-operative value was smaller than the pre-operative value (v: P < 0.001, θ: P = 0.0063) in the asymmetric group. For angulation and the X-component, the post-operative value was smaller than that pre-operatively on the deviated (angulation: P = 0.0074, X-component: P = 0.0003) and non-deviated (angulation: P = 0.0024, X-component: P = 0.001) side in the asymmetric group. However, there was no significant difference between the pre- and post-operative value for any parameter in the symmetric group.These findings suggest that surgical correction of mandibular prognathism, with and without asymmetry, could induce an improvement in stress balance on the TMJ in the frontal aspect. © The Author 2010. |
| Databáze: | OpenAIRE |
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