# Heat Generated during Dental Implant Placement: A Scoping Review
## 1 Introduction  
Bone tissue is a specialized connective tissue composed of cells embedded in a mineralized extracellular matrix. Ideal bone healing leads to complete restoration of both the morphology and function of the damaged tissue. In the realm of implant therapy, the successful integration of bone and implant without the interposition of soft tissue, known as osseeintegration, is based on the principle of bone regeneration [1]. Failure of osseeintegration due to interference in the healing process can result in what the literature refers to as \"early failure\" [2]. Extensive research has elucidated numerous factors that influence osseeintegration, including the characteristics of the implant screw, factors related to the bone site, diverse surgical protocols, implant biomechanics, the use of adjuvant treatments such as bone regeneration, drug therapies, and the general health status of the patient [1; 2; 3]. Regarding surgical protocols, heat generation during implant site preparation has been recognized as a critical factor affecting bone tissue viability and subsequent implant success [4; 5]. However, our understanding of the impact of heat generation during the osteotomy phase of implant placement remains incomplete. While there seems to be consensus that surgical interventions cause cell death to some extent [5], preservation of bone viability is critical for osseointegration [5; 6]. However, it is difficult to link biologic performance to one specific factor, i.e., temperature development vs. mechanical stress [7]. Based on an animal trial, it was concluded that the influence of drill speed and irrigation would be minimal in terms of the temperature of the cortical bone, primary and secondary implant stability, and osseointegration [5; 6; 7]. Given the widespread use of drilling as a technique for implant site preparation as well as the advanced devices available today, it has been questioned whether or not heat above the critical temperature for bone necrosis [8; 9] can be generated at all, if accepted protocols are followed. For conventional drilling, the following procedural parameters have been described [8; 9; 10] to affect temperature development: rotational speed, proceeding speed, contact pressure, drilling motion pattern, bone density [9; 10; 11; 12], drill depth [13], and irrigation [14; 15]. Variables related directly to drill design also seem to play a role, with the major parameters being the number of drill blades, drill design (tapered vs. straight) [16], drill fatigue, and drill material and its heat capacity and thermal conductivity [14; 15; 16; 17]. In an attempt to reduce surgery times, abbreviated drilling protocols have been advocated, for instance, using multistepped drills for single-stage implant site preparation [17]. In an animal trial, a novel drill design led to lower osteotomy temperature values and shorter drill times but also improved the osseointegration of dental implants [8]. In this context, low-speed drilling without irrigation has been shown to result in a greater quantity of and more beneficial cellular and histopathologic properties of harvested bone with even greater osteotomy precision [18]. Applying diamond-like carbon (DLC) coatings on drills has been claimed to optimize existing surgical approaches. DLC coatings have already been shown to bear superior tribological and mechanical properties, leading to improved wear properties as well as reduced friction between mechanical components [18; 19; 20]. With the goal of shortening overall treatment times, clinicians have been trying to insert implants with maximum primary stability in order to limit the risk of excessive micromotion at the implant-bone interface during healing in immediate loading cases [21]. The undersizing of an osteotomy as well as using a tapered implant resulting in bone compression have been described as effective approaches for reaching high insertion torque values [20; 21].