El-Sheikh Ali M, Abdel-Latif Hind H, Howell Peter G, Hobkirk John A
Department of Prosthetic Dentistry, Faculty of Dentistry, Tanta University, Tanta, Egypt.
Int J Oral Maxillofac Implants. 2007 Mar-Apr;22(2):243-8.
Mandibular deformation during function in patients with implant-supported prostheses is associated with increased strain at the bone-implant interface when dental implants are connected by a relatively rigid superstructure. Whilst there is a body of evidence concerning deformation as measured between the corpora, there are little data on its effects in the midline. This study measured 3 types of midline mandibular deformation during nonmasticatory functional mandibular movements in edentulous subjects with dental implants.
A range of custom displacement transducers was fabricated for 5 edentulous subjects who had been treated with dental implants in the anterior mandible. These transducers were mounted on contralateral implant abutments adjacent to the midline to measure medial convergence, corporal rotation, and anteroposterior shear. Their output was recorded for offline analysis by a personal computer.
The values of medial convergence ranged from 15 to 42 microm during opening, from 10 to 21 microm during lateral excursions, and from 18 to 53 microm during protrusion. Corporal rotation varied from 0.05 to 0.11 degrees during opening, from 0.03 to 0.08 degrees during lateral excursions, and from 0.03 to 0.15 degrees during protrusion. Anteroposterior shear varied from 38 to 93 pm during opening, from 28 to 56 microm during lateral excursions, and from 52 to 103 pm during protrusion.
Nonmasticatory physiological mandibular movements cause the jaw to deform about the midline in at least 3 directions. It is important for the clinician to be aware of the phenomenon of mandibular deformation, which should be taken into consideration in the design and monitoring of mandibular prostheses.
当牙种植体通过相对刚性的上部结构连接时，种植体支持的修复体患者在功能活动期间下颌骨变形与骨 - 种植体界面处应变增加有关。虽然有大量关于下颌体之间测量的变形的证据，但关于其在中线处影响的数据很少。本研究测量了无牙颌种植患者在非咀嚼性功能下颌运动期间的3种中线处下颌骨变形类型。
为5名在下颌前部接受牙种植治疗的无牙颌受试者制作了一系列定制的位移传感器。这些传感器安装在靠近中线的对侧种植体基台上，以测量内侧收敛、下颌体旋转和前后剪切。它们的输出由个人计算机记录以供离线分析。
开口期间内侧收敛值范围为15至42微米，侧方运动期间为10至21微米，前伸期间为18至53微米。下颌体旋转在开口期间为0.05至0.11度，侧方运动期间为0.03至0.08度，前伸期间为0.03至0.15度。前后剪切在开口期间为38至93微米，侧方运动期间为28至56微米，前伸期间为52至103微米。
非咀嚼性生理性下颌运动导致下颌骨至少在3个方向上围绕中线变形。临床医生了解下颌骨变形现象很重要，这在设计和监测下颌修复体时应予以考虑。
