Falk H
Department of Prosthetic Dentistry, Faculty of Odontology, University of Göteborg, Sweden.
Swed Dent J Suppl. 1990;69:1-40.
The main aims of this thesis were (1) to study the functional characteristics of dentitions with mandibular implant-supported fixed cantilever prostheses - IFCP s- occluding with complete dentures, (2) to study in detail the magnitudes and distributions of axially directed closing and chewing forces in such dentitions, (3) to study the influence of number and distribution of occlusal contacts on the magnitude and distribution of closing and chewing forces, (4) to assess the vertical bending moment and the resulting vertical bending stress in the cantilever joints and (5) to find out whether the force distribution over the cantilever beams and the resulting vertical bending stress in the cantilever joint are influenced by the type of prosthetic construction in the opposing jaw. Closing and chewing forces were registered in altogether seventeen subjects by means of miniature strain gauge transducers mounted bilaterally and symmetrically in performed matrices in prosthetic appliances. Four, six or eight transducers, evenly distributed over the tooth-arch, permitted registrations of axially directed occlusal forces in several occluding areas simultaneously. In Papers I-IV, the implant-supported prostheses were installed in the mandible and occluded with complete dentures. In Paper V, group A, the fixture-supported prostheses were installed in the maxilla and occluded with tooth-supported fixed partial dentures whereas in group B, the arrangements were analogous to those in Papers I-IV. All subjects exhibited a rhythmic chewing pattern and preferred one side for chewing although both sides were used. Most chewing sequences were terminated with swallowing with occlusal force development. The mean total forces acting over the tooth-arch varied somewhat between groups and occlusal arrangements but averaged 350 and 170 N for closing and chewing respectively. Closing and chewing forces increased distally along the cantilever beams when occluding with complete dentures and decreased distally when occluding with fixed partial dentures. The distally increasing force distribution pattern could be altered to a distally decreasing force distribution pattern by infraoccluding the second cantilever unit by as little as 100 microns. Calculated vertical bending moments and stresses in the cantilever joints of the preferred chewing sides created by closing and chewing forces were larger in dentitions where the IFCP occluded with a complete denture than in dentitions where the IFCP occluded with a tooth-supported fixed partial denture.
（1）研究下颌种植体支持的固定悬臂式假体（IFCP）与全口义齿咬合时牙列的功能特性；（2）详细研究此类牙列中轴向闭合和咀嚼力的大小及分布；（3）研究咬合接触的数量和分布对闭合和咀嚼力大小及分布的影响；（4）评估悬臂关节处的垂直弯矩及由此产生的垂直弯曲应力；（5）探究悬臂梁上的力分布以及悬臂关节处由此产生的垂直弯曲应力是否受对颌假体结构类型的影响。通过双侧对称安装在修复体预制基质中的微型应变片传感器，共记录了17名受试者的闭合和咀嚼力。在牙弓上均匀分布的四个、六个或八个传感器，可同时记录多个咬合区域的轴向咬合力量。在论文I - IV中，种植体支持的假体安装在下颌，与全口义齿咬合。在论文V的A组中，固定装置支持的假体安装在上颌，与牙支持的固定局部义齿咬合，而在B组中，其配置与论文I - IV中的类似。所有受试者均表现出有节奏的咀嚼模式，尽管两侧都会使用，但更倾向于一侧咀嚼。大多数咀嚼序列在咬合发力并吞咽时结束。作用于牙弓的平均总力在不同组和咬合配置之间略有差异，但闭合和咀嚼时的平均值分别为350 N和170 N。当与全口义齿咬合时，闭合和咀嚼力沿悬臂梁向远中方向增加，而与固定局部义齿咬合时则向远中方向减小。通过将第二个悬臂单元下调仅100微米，可将向远中增加的力分布模式改变为向远中减小的力分布模式。由闭合和咀嚼力在偏好咀嚼侧的悬臂关节处产生的计算垂直弯矩和应力，在IFCP与全口义齿咬合的牙列中比在IFCP与牙支持的固定局部义齿咬合的牙列中更大。
