Takahashi Toshihito, Gonda Tomoya, Mizuno Yoko, Fujinami Yozo, Maeda Yoshinobu
Int J Oral Maxillofac Implants. 2016 Sep-Oct;31(5):e136-42. doi: 10.11607/jomi.4535.
Maxillary implant overdentures are often used in clinical practice. However, there is no agreement or established guidelines regarding prosthetic design or optimal implant placement configuration. The purpose of this study was to examine the influence of palatal coverage and implant number and distribution in relation to impact strain under maxillary implant overdentures.
A maxillary edentulous model with implants and experimental overdentures with and without palatal coverage was fabricated. Four strain gauges were attached to each implant, and they were positioned in the anterior, premolar, and molar areas. A vertical occlusal load of 98 N was applied through a mandibular complete denture, and the implant strains were compared using one-way analysis of variance (P = .05).
The palatolabial strain was much higher on anterior implants than on other implants in both denture types. Although there was no significant difference between the strain under dentures with and without palatal coverage, palateless dentures tended to result in higher implant strain than dentures with palatal coverage. Dentures supported by only two implants registered higher strain than those supported by four or six implants.
Implants under palateless dentures registered higher strain than those under dentures with palatal coverage. Anterior implants exhibited higher palatolabial strain than other implants regardless of palatal coverage and implant configuration; it is therefore recommended that maxillary implant overdentures should be supported by six implants with support extending to the distal end of the arch.
上颌种植覆盖义齿在临床实践中经常使用。然而，关于修复体设计或最佳种植体植入配置尚无共识或既定指南。本研究的目的是研究上颌种植覆盖义齿的腭部覆盖、种植体数量和分布对冲击应变的影响。
制作带有种植体的上颌无牙颌模型以及有和没有腭部覆盖的实验性覆盖义齿。每个种植体上附着四个应变片，并将它们放置在前牙区、前磨牙区和磨牙区。通过下颌全口义齿施加98 N的垂直咬合负荷，并使用单因素方差分析比较种植体应变（P = .05）。
在两种义齿类型中，前牙区种植体的腭唇侧应变均远高于其他种植体。尽管有和没有腭部覆盖的义齿下的应变之间没有显著差异，但无腭义齿的种植体应变往往高于有腭部覆盖的义齿。仅由两个种植体支持的义齿的应变高于由四个或六个种植体支持的义齿。
无腭义齿下的种植体应变高于有腭部覆盖的义齿下的种植体应变。无论腭部覆盖和种植体配置如何，前牙区种植体的腭唇侧应变均高于其他种植体；因此，建议上颌种植覆盖义齿应由六个种植体支持，且支持范围延伸至牙弓远端。
