Takahashi Toshihito, Gonda Tomoya, Maeda Yoshinobu
Int J Oral Maxillofac Implants. 2015 Nov-Dec;30(6):1327-32. doi: 10.11607/jomi.3997. Epub 2015 Oct 16.
The purpose of this study was to examine the influence of reinforcement of an embedded cast on the strains within maxillary implant overdentures.
A maxillary edentulous model with implants placed bilaterally in the canine positions, dome-shaped copings, and experimental overdentures was fabricated. Rosette-type strain gauges were attached in the canine positions and at three points along the midline of the polished surface of the denture and connected to the sensor interface controlled by a personal computer. Experimental dentures with five different reinforcements were tested: without reinforcement; with a cast cobalt-chrome reinforcement over the residual ridge and the tops of the copings; with the same reinforcement from first molar to first molar, over the residual ridge and the tops of the copings; with the same reinforcement over the residual ridge and the sides of the copings; and with the same reinforcement from first molar to first molar, over the residual ridge and the sides of the copings. A vertical occlusal load of 49 N was applied to the first premolar and then to the first molar, and the strains were measured and compared by analysis of variance.
In both loading situations, significantly less strain was recorded in dentures with reinforcement than in those without reinforcement. When the first premolar was loaded on dentures with and without palatal reinforcement at the first premolars, the strains on the denture with reinforcement over the tops of the copings were significantly lower than on the denture with reinforcement over the sides of the copings at the canine position.
Cast reinforcement over the residual ridge and the top of copings embedded in an acrylic base reduced the strain from occlusal stress on maxillary implant overdentures.
本研究旨在探讨上颌种植覆盖义齿中嵌入式铸造加强件对义齿内应变的影响。
制作一个双侧尖牙位植入种植体、带有圆顶形顶盖及实验性覆盖义齿的上颌无牙颌模型。在尖牙位以及沿义齿抛光面中线的三个点处粘贴玫瑰花结型应变片，并连接至由个人计算机控制的传感器接口。对带有五种不同加强方式的实验性义齿进行测试：无加强；在剩余牙槽嵴及顶盖顶部有铸造钴铬合金加强；从第一磨牙到第一磨牙在剩余牙槽嵴及顶盖顶部有相同加强；在剩余牙槽嵴及顶盖侧面有相同加强；从第一磨牙到第一磨牙在剩余牙槽嵴及顶盖侧面有相同加强。对第一前磨牙施加49 N的垂直咬合负荷，然后对第一磨牙施加该负荷，并通过方差分析测量和比较应变。
在两种加载情况下，有加强的义齿所记录的应变均显著低于无加强的义齿。当对有和无前磨牙腭侧加强的义齿加载第一前磨牙时，在尖牙位，顶盖顶部有加强的义齿上的应变显著低于顶盖侧面有加强的义齿上的应变。
在丙烯酸基托内剩余牙槽嵴及嵌入式顶盖顶部进行铸造加强可降低上颌种植覆盖义齿咬合应力产生的应变。
