The use of ultrasonic equipment under adequate magnification may facilitate removal. It generates heat. Instrumentation without a coolant likely increases the temperature of the implant body and could cause tissue damage, in particular be harmful to osseointegration. The use of a coolant could be effective, but compromises visibility considerably, hence increases the risk of damaging the internal configuration of the implant.

Results from an experimental heat conduction model investigating the ranges of temperature gradients occurring in implants demonstrate that a 60°C heat source causes a heat front exceeding 47°C and advances more than 3 mm down an implant within 1 s [22]. Temperatures over 47°C for more than a minute cause necrosis of cortical bone [23-25]. Some studies investigating the potential harmfulness of intraoral abutment preparation or plaster on implants to osseointegration mention this threshold as harmful [26-28]. It has been postulated that a rise in temperature to 42°C causes denaturation of osteoblasts and should be considered the temperature threshold of transient changes in bone [25]. This threshold was used by others when investigating the potentially damaging effect to the implant-bone interface as a result of drinking hot beverages [29-31]. Also from endodontic literature regarding the removal of metal endodontic posts, concerns have been raised based on observations from in vitro experiments with respect to potentially detrimental heat transformation through dentine while ultrasonically manipulating the post [32-37].

The objective of this investigation is to examine the rise in temperature of the outer surface of an implant body after 30 s of ultrasonic instrumentation of its inner part in relation to type of ultrasonic equipment, implant type, and the use of coolants in vitro.