Clinical effects of conventional and underprepared drilling preparation of the implant site based on bone density: A systematic review and meta-regression

Abstract

Currently, one of the most important challenges in dental implant surgery is the optimization of techniques to obtain a high grade of stability. This is a key factor for survival and long-term predictability, especially in immediate loading procedures [1]. Implant stability can be classified as primary and secondary, which represent the mechanical retention of the bone at the time of implant insertion and the formation of biologically stable bone around the fixture, respectively [2,3].A commonly used surgical protocol to obtain increased primary stability consists of under-dimensioning the preparation of the site, especially in the case of low-density bone. With this technique, also called underpreparation or underized drilling, an implant is inserted in a substantially smaller osteotomy than its diameter, and is typically obtained by skipping the use of the last drill from the drilling protocol. This leads to an immediate direct contact of the implant surface with the bone, which promotes primary stability, and is clinically perceived as insertion torque (ITQ) [4]. The initial bone-toimplant contact then undergoes a major change during the healing period and while functioning. The increased lateral compression induced by underpreparation might affect the local microcirculation and bone cellular responses, leading to bone compression necrosis [5]. A review by Insua et al. [6] clarified the bases of bone metabolism during implant healing and the processes that can lead to peri-implant bone loss. The review consistently demonstrated, from a cel-J Prosthodont Res. 2022; **(**):

Hybrid Funnel Technique: A Novel Approach for Implant Site Preparation: A Pilot Study

“…A recent review has shown that there is a relationship between implant macro-geometry and the size of the osteotomy that can influence the osseointegration process [ 19 ].…”

“…Toia et al [ 18 ] observed that marginal bone level (MBL) was influenced by bone quality, implant diameter, insertion torque value (ITV), and the interaction between bone quality and ITV. It was estimated that MBL was greater with increased bone density and ITV [ 19 ].…”

“…It is richly vascularized and remodels much faster than cortical bone [ 14 ]. It can be deduced that an implant inserted with a high torque in bone type D1–D2 will show a greater MBL than an implant inserted with the same torque in bone type 4 [ 19 ].…”

Evaluation of Change in Radiographic Fractal Dimension around Dental Implants Placed with Low-Speed Drilling and Standard Drilling Protocols

“…Regarding the different radiological possibilities that technology offers us, most authors have traditionally used it to analyze the bone density of the bone area that concerns us in surgery [ 17 , 18 ].…”

Influence of different surgical techniques on primary implant stability in the posterior maxilla: a randomized controlled clinical trial

“…Underpreparation techniques could cause overheating or excessive compression of the cortical bone with the formation of microfractures [22]. The aforementioned authors recommend carefully selecting the drilling sequence based on bone density to achieve optimal primary stability and preserve crestal bone morphology [21]. In this way, it is important that the clinician knows how the surgical technique influences not only the PS but also all those factors that intervene in the success of implant therapy [17,18,23].…”