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The change of head posture after orthognathic surgery
022-A Orthognathie surgery oid, and the change of cranial and cervical angulations were measured on cephalometric radiographs. The results obtained from this study were as follows: 1. After mandibular setback operation, the airway dimension decreased to 81.6% of the preoperative state at 1 month postoperatively and to 89.7% at 1 year postoperatively. 2. The inferior movement of the hyoid was closely correlated with posterior movement of the tongue. 3. Postoperative anterior relapse of the mandible correlated with relapse of airway dimension. 4. Craniocervical angulation increased postoperatively. Especially in the early postoperative state, there was increased forward inclination of cervical angulation rather than increase of cranial angulation. One year postoperatively, however, the cervical inclination returned to the preoperative state and the cranial angulation increased. 5. Increased rate of airway dimension was correlated with the increase of cranial angulation from 1 month to 1 year postoperatively. Relapse tendency of airway dimension following increase of cranial angulation was found after mandibular setback surgery and it is considered that increase of cranial angulation is one of the compensatory mechanisms in airway maintenance.
5. The Change of Head Posture after Orthognathic Surgery
Park, J.-H., Yi, C.-K. Department of Oral and Maxillofitcial Surgery, Dental College, Yonsei University, Seoul, Korea According to the functional matrix theory the craniofacial structure of an individual is influenced by a balance between the surrounding skeletal structures including the cranial base, cranial vault and cervical vertebra and the soft tissues. Head posture may support equilibration in the cranio-cervical region by the intracranial aponeurotic system, posterior cervical musculo-aponeurotic system and anterior musculoaponeurotic system. The facial weight suspended to anterior cranial base is transported to the posterior cervical muscles by way of two intracranial dural aponeurotic systems. It is also related to the anterior musculo-aponeurotic system continuing to the cranial base from abdominal viscera, hyoid bone and mandible and thus, equilibration between craniofacial region and cervical region is accomplished by these muscles. The author tried to study the relationship between the craniocervical angle, airway adequacy and the position of the hyoid bone after alteration of the dentofacial structure through orthognathic surgery. Lateral cephalometric analysis was done on 117 normal Korean adults (61 male, 56 female) and 41 patients treated by orthognathic surgery. In spite of the change of the craniofacial structure postoperatively, the change of craniocervical angle was adapted to the change of the hyoid bone maintaining static airway adequacy.
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6. A Comparison of Postoperative Morphological and Functional Changes in Different Repositioning and Fixation Techniques of Proximal Segments in Sagittal Split Ramus Osteotomy
lwase, M., Sakurada, S., Kurachi, Y., Nagumo, M. 2nd Department of OMS, School of Dentistry, Showa Univ. Tokyo, Japan The purpose of this study was to compare postoperative functional and morphological changes in different repositioning and fixation techniques of the proximal segment in sagittal split ramus osteotomy (SSRO). The proximal segment was repositioned by the two-dimension method with stiff wires (n=25) or the three-dimension method with readymade bone plate appliances (n= 13). The proximal and distal segments were osteosynthesized with cirumferential wiring (n = 17), bicortical positioning screw (n = 26), or monocortical T-shaped mini-plate (n=29). Functional analysis was performed by estimating voluntary bite force using the T-scan system, and maximal interincisal opening postoperatively. Morphological study was performed by analyzing lateral, frontal, and axial radiograms. Although postoperative stability in the position of the condyle with the three-dimensional method was superior to the two-dimensional method, there were no differences in postoperative mandibular motion, occurrence of temporomandibular disorder (TMD), or skeletal relapse. Rigid fixations with screws and plates could decrease the duration of maxillomandibular fixation and thus accomplished early recovery in mandibular motion and early acquisition in bite force when compared with non-rigid wire fixation. Rigid fixation also reduced skeletal relapse. The occurrence of T M D in rigid and non-rigid fixation was almost equal. There were no differences in postoperative skeletal changes between the use of positioning screws and mini-plate. Moreover, becaus e mini-plate fixation allows a transoral approach, the technique could reduce paresthesia and obstinate skin scarring. These observations revealed that two-dimensional repositioning of the proximal segment with mini-plate fixation for osteosynthesis is a valuable technique in SSRO.
7. Neurosensory Differences Between Wire And Rigid Fixation
Lemke, R), Tran, 34.1, Rugh, j.1, Clark, G.2, VanSickels, j.l, Bays, R. 3 1Department of Orthodontics, 2Department of Medicine, University of Texas Health Science Center 3Emory University Atlanta, USA Bilateral sagittal split osteotomy (BSSO) is a standard technique for mandibular advancement or setback. Recently, wire fixation has been replaced with rigid fixation. Increased potential for nerve damage from rigid fixation's screws has led some to suggest higher rates of anesthesia. To date no
5. The Change of Head Posture after Orthognathic Surgery
Park, J.-H., Yi, C.-K. Department of Oral and Maxillofitcial Surgery, Dental College, Yonsei University, Seoul, Korea According to the functional matrix theory the craniofacial structure of an individual is influenced by a balance between the surrounding skeletal structures including the cranial base, cranial vault and cervical vertebra and the soft tissues. Head posture may support equilibration in the cranio-cervical region by the intracranial aponeurotic system, posterior cervical musculo-aponeurotic system and anterior musculoaponeurotic system. The facial weight suspended to anterior cranial base is transported to the posterior cervical muscles by way of two intracranial dural aponeurotic systems. It is also related to the anterior musculo-aponeurotic system continuing to the cranial base from abdominal viscera, hyoid bone and mandible and thus, equilibration between craniofacial region and cervical region is accomplished by these muscles. The author tried to study the relationship between the craniocervical angle, airway adequacy and the position of the hyoid bone after alteration of the dentofacial structure through orthognathic surgery. Lateral cephalometric analysis was done on 117 normal Korean adults (61 male, 56 female) and 41 patients treated by orthognathic surgery. In spite of the change of the craniofacial structure postoperatively, the change of craniocervical angle was adapted to the change of the hyoid bone maintaining static airway adequacy.
61
6. A Comparison of Postoperative Morphological and Functional Changes in Different Repositioning and Fixation Techniques of Proximal Segments in Sagittal Split Ramus Osteotomy
lwase, M., Sakurada, S., Kurachi, Y., Nagumo, M. 2nd Department of OMS, School of Dentistry, Showa Univ. Tokyo, Japan The purpose of this study was to compare postoperative functional and morphological changes in different repositioning and fixation techniques of the proximal segment in sagittal split ramus osteotomy (SSRO). The proximal segment was repositioned by the two-dimension method with stiff wires (n=25) or the three-dimension method with readymade bone plate appliances (n= 13). The proximal and distal segments were osteosynthesized with cirumferential wiring (n = 17), bicortical positioning screw (n = 26), or monocortical T-shaped mini-plate (n=29). Functional analysis was performed by estimating voluntary bite force using the T-scan system, and maximal interincisal opening postoperatively. Morphological study was performed by analyzing lateral, frontal, and axial radiograms. Although postoperative stability in the position of the condyle with the three-dimensional method was superior to the two-dimensional method, there were no differences in postoperative mandibular motion, occurrence of temporomandibular disorder (TMD), or skeletal relapse. Rigid fixations with screws and plates could decrease the duration of maxillomandibular fixation and thus accomplished early recovery in mandibular motion and early acquisition in bite force when compared with non-rigid wire fixation. Rigid fixation also reduced skeletal relapse. The occurrence of T M D in rigid and non-rigid fixation was almost equal. There were no differences in postoperative skeletal changes between the use of positioning screws and mini-plate. Moreover, becaus e mini-plate fixation allows a transoral approach, the technique could reduce paresthesia and obstinate skin scarring. These observations revealed that two-dimensional repositioning of the proximal segment with mini-plate fixation for osteosynthesis is a valuable technique in SSRO.
7. Neurosensory Differences Between Wire And Rigid Fixation
Lemke, R), Tran, 34.1, Rugh, j.1, Clark, G.2, VanSickels, j.l, Bays, R. 3 1Department of Orthodontics, 2Department of Medicine, University of Texas Health Science Center 3Emory University Atlanta, USA Bilateral sagittal split osteotomy (BSSO) is a standard technique for mandibular advancement or setback. Recently, wire fixation has been replaced with rigid fixation. Increased potential for nerve damage from rigid fixation's screws has led some to suggest higher rates of anesthesia. To date no