Kazokoğlu F Şehnaz, Akaltan Funda
Assistant Professor, Department of Prosthodontics, Faculty of Dentistry, Okan University, Istanbul, Turkey.
Professor, Department of Prosthodontics, Faculty of Dentistry, Ankara University, Ankara, Turkey.
J Prosthet Dent. 2014 Dec;112(6):1416-24. doi: 10.1016/j.prosdent.2014.05.013. Epub 2014 Jun 24.
It is hard to identify the most favorable retainer type and the denture design when considering strain levels around implants and in edentulous ridges for implant overdentures (IOVD).
The purpose of this study was to evaluate the strain transmitted to the implants and edentulous ridges by Marburg double crown (MDC)-retained IOVD as opposed to bar and ball-retained IOVD and the efficiency of a rigid major connector in the maxilla.
An in vitro maxillary model was prepared with 4 implants, with strain gauges placed distally to each implant and also in the anterior and posterior edentulous ridges. Five overdentures were fabricated for each MDC and each ball and bar attachment retainers. Vertical loads of 280 N were applied bilaterally on the first molar region. Then the palatal bars of each IOVD were disconnected, and loading procedures were repeated for the prostheses.
No significant difference was observed among the MDC and the bar and ball-retained IOVD, with and without a rigid bar according to the data taken from both the implants and edentulous ridges. However, when the strain values attained from each strain gauge separately were considered, a slight difference was observed around the implants of ball-retained overdentures and in the edentulous ridges of MDC-retained overdentures.
Within the limitations of this in vitro study, MDC-retained maxillary overdentures with 4 parallel and symmetrically placed implants can be used safely without a rigid major connector as with bar and ball-retained IOVD with regard to the strains generated in the edentulous ridge and around implants.
在考虑种植覆盖义齿（IOVD）种植体周围和无牙颌骨中的应变水平时，很难确定最有利的固位体类型和义齿设计。
本研究的目的是评估与杆卡式和球帽式固位的IOVD相比，马尔堡双冠（MDC）固位的IOVD传递至种植体和无牙颌骨的应变，以及上颌刚性主连接体的效率。
制备一个带有4颗种植体的上颌体外模型，在每颗种植体远中以及无牙颌骨的前部和后部放置应变片。为每个MDC、每个球帽式和杆卡式附着体固位制作5副覆盖义齿。在第一磨牙区域双侧施加280 N的垂直载荷。然后断开每个IOVD的腭杆，对义齿重复加载程序。
根据从种植体和无牙颌骨获取的数据，在有或没有刚性杆的情况下，MDC固位、杆卡式固位和球帽式固位的IOVD之间未观察到显著差异。然而，当分别考虑每个应变片获得的应变值时，在球帽式固位覆盖义齿的种植体周围和MDC固位覆盖义齿的无牙颌骨中观察到轻微差异。
在本体外研究的局限性内，就无牙颌骨和种植体周围产生的应变而言，带有4颗平行且对称放置种植体的MDC固位上颌覆盖义齿可以像杆卡式和球帽式固位的IOVD一样，在没有刚性主连接体的情况下安全使用。
