Implant removal using thermal necrosis—an in vitro pilot study

Abstract

Objectives The purpose of this pilot porcine cadaver study was to evaluate the feasible temperature thresholds, which affect osteocyte viability and bone matrix in a preclinical setup, assessing the potential of thermal necrosis for implant removal for further in vivo investigations. Materials and methods After implant bed preparation in the upper and lower jaw, temperature effects on the bone were determined, using two tempering pistons with integrated thermocouples. To evaluate threshold temperature and time intervals leading to bone necrosis, one piston generated warm temperatures at 49 to 56 °C for 10 s and the other generated cold temperatures at 5 to 1 °C for 30 s. Effects were assessed by a semi-quantitative, histomorphometrical scoring system, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM). Results The bone matrix was significantly degenerated starting at 51 °C for 10 s and 5 °C for 30 s. The osteocyte condition indicated significant bone damage beginning at cold temperatures of 2 °C. Temperature inputs starting at 53 °C led to decalcification and swollen mitochondria, which lost the structure of their inner cristae. Conclusions This study identified temperatures and durations, in both heat and cold, so that the number of samples may be kept low in further studies regarding temperature-induced bone necrosis. Levels of 51 °C for 10 s and 5 °C for 30 s have presented significant matrix degeneration. Clinical relevance Temperature thresholds, potentially leading to thermo-explantation of dental implants and other osseointegrated devices, were identified.

Reversal of Osseointegration as a Novel Perspective for the Removal of Failed Dental Implants: A Review of Five Patented Methods

“…Preliminary calculations and ongoing research [40,67] confirm that the method described in P5 is clinically applicable with conventional implants. It is particularly suitable for implants containing a long channel along their rotational axis, facilitating more homogeneous heating (or cooling) of the implants and, consequently, minimizing the extent of the denatured bone.…”

“…The contact between the connecting device and the implant can be a point, line, or surface contact. The thermal conductivity may be increased using a highly thermal compound material (40) [51]. However, Figure 1 of P1 shows that the connecting device only reaches about halfway into the implant.…”

“…Therefore, the control of the temperature at the bone-implant interface is the primary concern in all these methods. It is essential to precisely temper all parts of the implant surface to a defined temperature for a defined duration [35][36][37][38][39][40] to ensure that only a thin layer of bone degenerates and healing occurs quickly and without complications. Heating implants to achieve osseodisintegration without a precise and reliable method of temperature control is problematic due to the risk of widespread necrosis.…”

“…The authors recommended in-depth clinical studies to gain further insight into the potential of thermal necrosis for implant removal [38]. An in vitro pilot study on the induction of thermal necrosis for implant removal showed significant degeneration of the bone matrix at 51 • C for 10 s and 5 • C for 30 s [40].…”

In vivo and in vitro analysis in a rat model using zoledronate and alendronate medication: microbiological and scanning electron microscopy findings on peri-implant rat tissue

“…For each method nine collected samples were used. The samples for SEM were fixed in 3% glutaraldehyde in 0.1 M Sorensen’s phosphate buffer, dehydrated in an ascending ethanol series (30–100%), and dried at 37 °C (SEM and EDX) according to a previously published study [ 33 ]. The samples were analyzed using an environmental scanning electron microscope (ESEM XL 30 FEG; FEI, Eindhoven, Netherlands) in backscatter mode with an acceleration voltage of 15 kV.…”