A three-dimensional method to calculate mechanical advantage in mandibular function : Intra- and interexaminer reliability study.
J Orofac Orthop
; 84(5): 321-339, 2023 Sep.
Article
em En
| MEDLINE
| ID: mdl-35254453
PURPOSE: Masticatory muscles are physically affected by several skeletal features. The muscle performance depends on muscle size, intrinsic strength, fiber direction, moment arm, and neuromuscular control. To date, for the masticatory apparatus, only a two-dimensional cephalometric method for assessing the mechanical advantage, which is a measure for the ratio of the output force to the input force in a system, is available. This study determined the reliability and errors of a three-dimensional (3D) mechanical advantage calculation for the masticatory system. METHODS: Using cone-beam computed tomography images from teenage patients undergoing orthodontic treatments, 36 craniofacial landmarks were identified, and the moment arms for seven muscles and their load moment arms (biomechanical variables) were determined. The 3D mechanical advantage for each muscle was calculated. This procedure was repeated by three examiners. Reliability was verified using the intraclass correlation coefficient (ICC) and the errors by calculating the absolute differences, variance estimator and coefficient of variation (CV). RESULTS: Landmark coordinates demonstrated excellent intra- and interexaminer reliability (ICC 0.998-1.000; pâ¯< 0.0001). Intraexaminer data showed errors <â¯1.5â¯mm. Unsatisfactory interexaminer errors ranged from 1.51-5.83â¯mm. All biomechanical variables presented excellent intraexaminer reliability (ICC 0.919-1.000, pâ¯< 0.0001; CVâ¯< 7%). Interexaminer results were almost excellent, but with lower values (ICC 0.750-1.000, pâ¯< 0.0001; CVâ¯< 10%). However, the muscle moment arm and 3D mechanical advantage of the lateral pterygoid muscles had ICCsâ¯< 0.500 (pâ¯< 0.05) and CVâ¯< 30%. Intra- and interexaminer errors were ≤â¯0.01 and ≤â¯0.05, respectively. CONCLUSIONS: Both landmarks and biomechanical variables showed high reliability and acceptable errors. The proposed method is viable for the 3D mechanical advantage measure.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Imageamento Tridimensional
/
Mandíbula
Tipo de estudo:
Prognostic_studies
Limite:
Adolescent
/
Humans
Idioma:
En
Revista:
J Orofac Orthop
Assunto da revista:
ODONTOLOGIA
/
ORTODONTIA
Ano de publicação:
2023
Tipo de documento:
Article
País de afiliação:
Brasil
País de publicação:
Alemanha