Simplified Drilling Technique Does
Not Decrease Dental Implant
Osseointegration: A Preliminary Report
Ryo Jimbo,* Gabriela Giro,† Charles Marin,‡ Rodrigo Granato,‡ Marcelo Suzuki,§
Nick Tovar,† Thomas Lilin,i Malvin Janal,¶ and Paulo G. Coelho†
Background: To date, some experimental studies have addressed the effect of bone drilling technique and sequence on dental implant osseointegration. In the present study, the authors hypothesize that there would be no differences in osseointegration when reducing the number of drills for osteotomy compared to the conventional drilling protocols.
Methods: Seventy-two implants (diameters 3.75 mm and 4.2 mm; n = 36 for each diameter) were bilaterally placed in the tibia of 18 beagles for 1, 3, and 5 weeks. Half of the implants of each diameter were placed using a simplified drilling procedure (pilot and final drill), and the other half were placed using a conventional drilling procedure (all drills in sequence). The retrieved samples were subjected to histologic and histomorphometric evaluation.
Results: Histology showed that new bone formed around the implant, and inflammation or bone resorption was not evident for both groups. Histomorphometrically, the simplified group presented significantly higher bone-to-implant contact and bone area fraction occupancy compared to the conventional group after 1 week; however, no differences were detected at 3 and 5 weeks.
Conclusion: Bone responses to the implant with the simplified protocol can be comparable to the conventional protocol. J Periodontol 2013;84:1599-1605.
Histology; oral surgery procedures, osseointegration; osteonecrosis; osteotomy.
O nly 4 decades ago, it was still considered that any material implanted into bone would be subjected to fibrous encapsulation.1 It was only after the discovery of the osseointegrated implants that the possibility of having a foreign material implanted successfully in the body was recognized,2,3 and needless to say, the osseointegrated implant has become a reliable treatment option in dentistry.
As has been suggested by Albrektsson et al.,4 reliable osseointegration is dependent on six factors: 1) implant biocompatibility, 2) implant design, 3) implant surface, 4) state of host bed, 5) surgical technique, and 6) loading conditions. All these factors have evolved since first defined as key for successful osseointegration. For instance, implant biocompatibility has significantly improved with time because of the development of possibly bioactive surfaces such as the calcium phosphate–coated or fluoride-treated surfaces.5-7 Interestingly enough, implant macro design has converged to a similar design, especially in the neck portion with pitch-shortened threads, which has been shown to disperse strain and minimize its concentration.8,9
With regard to implant surface, the traditional surface design was turned; however, studies have shown that moderately roughened microtopography * Department of Prosthodontics, Faculty of Odontology, Malmo¨ University, Malmo¨, Sweden. † Department of Biomaterials and Biomimetics, New York University, New York, NY. ‡ Department of Dentistry, Federal University of Santa Catarina, Florianopolis, SC, Brazil. § Department of Prosthodontics, Tufts University School of Dental Medicine, Boston, MA. i Department of Experimental Research, National Veterinary School of Alfort, MaisonsAlfort, France. ¶ Department of Epidemiology and Health Promotion, New York University. doi: 10.1902/jop.2012.120565
J Periodontol • November 2013 1599 along with nanotopography <100 nm presented improved bone responses,10,11 and most of the commercially available implants existing on the market today possess these features.
State of the host bed, in combination with loading conditions, has been discussed, both in clinical reality and in animal studies.12,13 It has been shown that the biologic crestal bone alteration is inevitable, and most of these initial bone losses occur without any signs of infection.14
Concerning surgical technique alteration, there has not been a significant amount of basic clinical research that led to radical modification in the field because irrigation with sharp drills, low speed, and graded series of drills have been the universal gold standard for successful osseointegration. However, questions remain whether the suggested protocol today is based on solid evidence or clinical experience. The recommended drilling protocols provided by the manufacturers differ depending on the implant company, mainly to obtain maximum initial stability for mechanical fixation or no stability (for direct osteogenesis).
The basic concept of the drilling sequence is gradual expansion of the osteotomy sites. This is beneficial when there is a need to correct the location or the angulation of the drilling for optimal prosthetic buildup. However, it must be posed that the optimal drilling protocol has not been fully clarified, and there remains room for challenging the gradual expansion protocol with a simplified drilling procedure. Gradual expansion of the osteotomy site is admittedly time consuming. Moreover, it has been suggested that surgical site exposure time and the total operation time have an influence on the incidence of surgical site infections.15 Thus, it can be hypothesized that reducing the drilling steps may shorten the surgical time and potentially reduce infection. Intuitively, when one reduces the number of drills to prepare bone to a given diameter before implantation, one concern is bone overheating, possibly generated by the larger drill expansion rate, which in fact may result in osteonecrosis.16 It must be noted that this can actually be prevented by thorough low temperature saline irrigation.17
In as much as the literature concerning the effects of drilling sequence and technique in osseointegration is sparse and contradictory, the present study hypothesizes that implants placed in osteotomy sites with reduced drilling steps (pilot drill and final drill) would present comparable biologic outcomes (i.e., histology and histomorphometry) relative to the conventional drilling protocols, provided that thorough irrigation prevented overheating the bone.