Alzahrani Khaled Mosfer
Prince Sattam Bin Abdulaziz University, College of Dentistry, Riyadh, Saudi Arabia.
J Int Soc Prev Community Dent. 2020 Nov 24;10(6):700-714. doi: 10.4103/jispcd.JISPCD_138_20. eCollection 2020 Nov-Dec.
Dental implants are considered the best treatment option for replacement of missing teeth due to high survival rates and diverse applications. However, not all dental implant therapies are successful and some fail due to various biological and or/mechanical factors. The objective of this study was to systematically review primary studies that focus on the biomechanical properties of dental implants in order to determine which biomechanical properties are most important for success of dental implant therapy.
An electronic database search was performed using MEDLINE (PubMed), EMBASE, Google Scholar, and CAB Abstracts. Six principal biomechanical properties were considered to prepare the search strategy for each database using key words and Boolean operators. Human and animal studies (observational studies, trials, and studies) were included in this review. Human studies that were considered eligible needed to have subjects above 18 years who received permanent restorations after implant surgery and followed up for at least 6 months after receiving permanent restorations. Studies with subjects who had absolute contraindications at the time of dental implant surgery were excluded.
In total, 28 studies were included in the review after application of the eligibility criteria; 18 studies, 5 cohort clinical studies, 3 animal studies, and 2 nonrandomized trials. Six studies assessed loss of preload, five studies assessed fatigue strength, four assessed implant abutment connection design, and one assessed implant diameter. Two nonrandomized trials assessed torque and six observational studies assessed the effect of cantilevers. Gold alloy coating of abutment screws resulted in higher preload values followed by titanium alloy coating and gold coating; there was a difference in preload values between coated and uncoated screws when tightened repeatedly. Preload values decreased as a function of time with majority of preload loss occurred within 10s of tightening. The 8-degree internal conical implant performed better than the internal hex design. Higher rate of complications (porcelain chipping, de-cementation) was observed in the cantilever groups in studies.
Biomechanical properties of implants like preload, torque, cantilever design, implant abutment design have profound effects on the survival rates of dental implants. With limiations, this review provides some important parameters to consider for successful implant therapy.
由于高生存率和多样的应用，牙种植体被认为是缺失牙替代的最佳治疗选择。然而，并非所有牙种植治疗都能成功，有些因各种生物学和/或机械因素而失败。本研究的目的是系统评价关注牙种植体生物力学特性的原始研究，以确定哪些生物力学特性对牙种植治疗的成功最为重要。
使用MEDLINE（PubMed）、EMBASE、谷歌学术和CAB文摘进行电子数据库检索。考虑了六个主要生物力学特性，使用关键词和布尔运算符为每个数据库制定检索策略。本综述纳入了人类和动物研究（观察性研究、试验和研究）。被认为合格的人类研究需要有18岁以上的受试者，他们在种植手术后接受了永久修复，并在接受永久修复后随访至少6个月。排除在牙种植手术时有绝对禁忌证的受试者的研究。
应用纳入标准后，本综述共纳入28项研究；18项研究、5项队列临床研究、3项动物研究和2项非随机试验。六项研究评估了预紧力损失，五项研究评估了疲劳强度，四项评估了种植体基台连接设计，一项评估了种植体直径。两项非随机试验评估了扭矩，六项观察性研究评估了悬臂的影响。基台螺钉的金合金涂层导致更高的预紧力值，其次是钛合金涂层和金涂层；反复拧紧时，涂层螺钉和未涂层螺钉的预紧力值存在差异。预紧力值随时间下降，大部分预紧力损失发生在拧紧后10秒内。8度内锥形种植体的性能优于内六角设计。在研究中，悬臂组观察到较高的并发症发生率（瓷片剥落、脱粘）。
种植体的生物力学特性如预紧力、扭矩、悬臂设计、种植体基台设计对牙种植体的生存率有深远影响。尽管存在局限性，但本综述提供了一些成功种植治疗需要考虑的重要参数。
