Postgraduate student, Department of Prosthodontics, Dental School, Isfahan University of Medical Sciences, Isfahan, Iran.
Professor, Dental Implants Research Center and Department of Prosthodontics, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran.
J Prosthet Dent. 2019 Jan;121(1):52-58. doi: 10.1016/j.prosdent.2018.03.002. Epub 2018 Jul 10.
Cement-retained implant-supported prostheses eliminate screw loosening and enhance esthetics. However, retrievability and the possibility of removing extruded excess cement (EEC) have been problematic.
The purpose of this systematic review was to analyze the effects of modifying the screw access channel (SAC) on the amount of EEC and the retention of cement-retained implant-supported prostheses.
PubMed, Web of Science, Scopus, and Google Scholar databases were searched with appropriate key words. Related titles and abstracts published up to June 2017 were screened and selected on the basis of defined inclusion criteria. Full texts of all studies were read and subjected to quality assessments. After the initial search, 1521 articles were included in the study. Of these, 11 studies were subjected to critical appraisal, and 10 of them were reliable enough in methodology to be systemically reviewed.
All the studies were in vitro and described a total of 260 specimens. According to the interpreted results, closed SACs caused lower retention with a higher amount of EEC, whereas open SACs caused the reverse. Also, as the abutment height decreased, retention decreased.
Extending the crown's margin into the SAC, leaving the SAC open, and using internal vents in the SAC space are possible methods of modifying the SAC to gain higher retentive values. Also, the use of internal vents in the SAC system and open or partially filled SAC space reduce the amount of EEC.
黏结固位种植体支持式修复体可消除螺丝松动并增强美观性。但是，其可取出性和去除挤出的多余黏固剂（EEC）的可能性存在问题。
本系统评价的目的是分析修改螺丝通道（SAC）对 EEC 量和黏结固位种植体支持式修复体保留率的影响。
通过适当的关键词，在 PubMed、Web of Science、Scopus 和 Google Scholar 数据库中进行检索。筛选并选择截至 2017 年 6 月发布的相关标题和摘要，根据既定的纳入标准进行选择。阅读所有研究的全文并进行质量评估。初步搜索后，共有 1521 篇文章纳入研究。其中，有 11 项研究进行了批判性评价，其中 10 项研究在方法上足够可靠，可进行系统综述。
所有研究均为体外研究，共描述了 260 个样本。根据解释结果，封闭 SAC 会导致较低的保留率和较高的 EEC 量，而开放 SAC 则相反。此外，随着基台高度的降低，保留率降低。
将冠边缘延伸到 SAC 中、保持 SAC 开放以及在 SAC 空间内使用内部通风口是修改 SAC 以获得更高保留值的可能方法。此外，在 SAC 系统中使用内部通风口以及开放或部分填充的 SAC 空间可减少 EEC 的量。
