Page 54 - Dental Practice South Asia 18-6

implantology section

A SLOW DRILLING OSTEOTOMY PROTOCOL

DR. ALY VIRANI

Aly Virani explores the evidence surrounding temperature changes on the bone to examine
why faster does not necessarily mean better in implant preparations.

Conventional osteotomy preparation in modern implant dentistry bone as this is the temperature at which alkaline phosphatases
involves using saline irrigation and drilling speeds ranging from denature.
800 to 1,200rpm. These high speeds reduce the friction produced These hard tissue proteins are found in various tissues, but they
while the irrigant limits temperature increases in the bone, allow- are crucial for the osteogenesis process. Then, in 1982, a research
ing quick osteotomy preparation. team from the University of Gothenburg led by Tomas Albrektsson
Osseointegration rates are high, and the process is predictable, did a study on hares using live microscopy to look at the effect of
so why consider changing this? The evidence contains hidden clues heat on implants placed into the hares' bones. They noticed that
that may have implications beyond initial osseointegration. above 40°C, hyperemia occurred in the tissues, and at 53°C, blood
Perhaps conventional osteotomy preparation protocols could lead flow stopped completely. It took four to five weeks following
to long-term complications around implants that are still not ade- ischemia for the vasculature to recover. The behaviour of fat cells
quately understood. dominated their connective tissue observations.
Slow drilling and the reduced potential for temperature increase After being heated at 53°C for one minute, the fat cells appeared
in the alveolus might be a solution to some late difficulties around necrotic after two days. After three weeks, the majority of fat cells
implants that are not yet fully understood. Regardless of the possi- had resorbed. Functional vasculature is needed for the resorption
bility of the impact on long-term peri-implant tissue health, slow and replacement of new cells, suggesting that the vasculature had
drilling could also positively impact surgical techniques and proto- recovered at the six-to-eight-week mark when fat cells reached their
cols for bone grafting and guided surgery. original numbers. At this point, bone resorption dominated the
picture and alerted the team to the possibility of bone loss related
UNDERSTANDING TEMPERATURE to fat cell behaviour. It also confirmed that the safe temperature for
To comprehend the possible benefits of slow drilling, it is necessary bone is below 53°C.
first to understand the history of research on temperature effects on
bone metabolism and the scientific basis for the protocol's practical UNDERESTIMATING DAMAGE
consideration. At the beginning of the 1980s, research teams strug- The study by Albrektsson's team also highlights the danger with
gled to devise a methodology to test temperature increase on bone many other studies that have looked at the effect of temperature on
health. They agreed that temperatures above 56°C would harm the bone – they underestimate the damage caused to bone cells by tem-

FIG 1a-e: Bone can be extracted directly from the
drill flutes using a sterile instrument. It should be
placed on saline-moistened sterile gauze; however,
it should not be submerged in saline since this
would result in the loss of soluble signalling
molecules.

54 Dental Practice // November-December 2022 // Vol 18 No 6