Effects of Bur Wear during Implant Site Preparation: An in Vitro Study

Abstract

Background: Few studies have investigated the influence of drilling on bone healing. After the drilling of bone and placement of dental implants a sequence begins of cellular and molecular events which represents a combined response of wound healing. The bone healing around dental implants is a complex phenomenon and influences the proliferation and differentiation of pre-osteoblasts into osteoblasts, together with the activation of periosteal and endosteal lining cells, and initiates the production and mineralization of osteoid matrix followed by the organization of the bone-implant interface. The objective of this study is to quantify the temperature changes in cortical bone and marrow spaces during implant site preparation in bovine rib bone. A total 10 harvested bovine ribs and 6 10.5 × 3.5 new drills for implant insertion with external irrigation (Bone System, Milano, Italy) were used in this study. The implant sites were prepared with 10 mm long drills at 500 rpm under abundant external irrigation with saline solution at 37°C. Each drill was used for 10, 30, 60, 90 and 120 implant site preparations; each drill was then observed under SEM for evaluation of the damage of the cutting edge after 10, 30, 60, 90 and 120 preparations. There was an higher and statistically significant increase in the temperature in the cortical bone; this increase in temperature increases with the number of the times of drill use. The drill wear seemed to play a major role in heat production and could explain the observed increased temperature of the bone.

Heat generation and drill wear during dental implant site preparation: systematic review

“…2,[12][13][14][15][16][17][18][19][20][21][22][23][24][25] Three studies used synthetic blocks, 21,26,27 and one a resin model. 28 In 3 animal studies, immunohistochemical analysis was done to check the viability of bone cells.…”

“…4 Recent studies have investigated the wear of the drill itself. 2,[12][13][14]17,29,30,38 Descriptive analyses have been done using scanning electron microscopy, and mechanical studies have been based on the electrical power from the torque and tension of the drill. The objective of these studies was to measure the durability of twist drills after multiple uses and the effect on the bone.…”

“…The waste of drills used for dental implant surgery was the focus in recent studies. Until now, scanning electron microscopy (SEM) has been used to analyse wear of the drill, 2,12,14,17,29,30,38 and qualitative analysis of bony healing has been done immunohistochemically. 2,[29][30][31] SEM has shown small defects on new drills 38 and a high correlation between the amount of damage and number of uses has been seen.…”

“…Until now, scanning electron microscopy (SEM) has been used to analyse wear of the drill, 2,12,14,17,29,30,38 and qualitative analysis of bony healing has been done immunohistochemically. 2,[29][30][31] SEM has shown small defects on new drills 38 and a high correlation between the amount of damage and number of uses has been seen. After 50 preparations the surface was corroded and degraded, and the plastic was deformed, but the differences in 2 Investigations on bony healing in rabbit tibias found no association between the number of times a drill was used and bony healing.…”

“…1 Repeated use causes drills to wear and reduces their efficiency, and the temperature increases each time a bur is used. 2 Other variables may also affect their cutting ability and the amount of heat generated. Preparation…”