The Effect of Osseodensification on Ridge Expansion, Intraosseous Temperature, and Primary Implant Stability: A Pilot Study on Bovine Ribs
Osseodensification is a novel technique based on nonsubtractive drilling to preserve and condense bone during osteotomy preparation. The aim of this ex vivo study was to compare osseodensification and conventional extraction drilling technique with regard to intraosseous temperatures, expansion of alveolar ridge width, and primary implant stability using different implant geometries: tapered and straight walled. A total of 45 implant sites were prepared in bovine ribs following osseodensification and conventional protocols. Changes in intraosseous temperatures were recorded at 3 depths using thermocouples, and ridge width was measured at 2 different depths before and after osseodensification preparations. The primary implant stability was measured using peak insertion torque and the implant stability quotient (ISQ) following placement of straight and tapered implants. A significant change in temperature was recorded during site preparation for all techniques tested but not at all depths. Osseodensification recorded higher mean temperatures (42.7°C) than conventional drilling, particularly at the midroot level. Statistically significant ridge expansion was observed at both the crestal and apical levels in the osseodensification group. The ISQ values were significantly higher only for tapered implants placed in osseodensification sites when compared with conventional drilling sites; however, there was no difference in the primary stability between tapered and straight implants within the osseodensification group. Within the limitations of the present pilot study, osseodensification was found to increase the primary stability of straight-walled implants without overheating the bone and significantly expanded the ridge width. However, further investigation is required to determine the clinical significance of the bone expansion created by this new technique.
Experimental setup with the bovine rib sample held in place by a drill vice, over a digital scale. The implant bur is held in a 20:1 contra-angle handpiece and drilled perpendicular to the surface of the bone sample.
Positioning of all 3 thermocouples (T1, T2, and T3) in relation to the osteotomy site (a, b). Pictorial diagram depicting the distances between thermocouples and osteotomy (c), which was standardized using a laser-cut acrylic guide.
Placement of implants in the osteotomy until fully seated using the manual torque wrench to obtain peak insertion torque (PIT) values (a). Resonance frequency analysis as a measure of primary stability using the PenguinRFA (Neoss) device. The MulTipeg titanium transducer is attached to the implant, and the PenguinRFA is held 1 mm away from the transducer in the buccolingual orientation (b).
Mean intraosseous temperature measured as a function of drilling technique at 3 different depths. No temperatures during preparation exceeded the 47°C threshold for osteonecrosis. *P < .05 (significance from respective baseline average). **P < .001 (significance from respective baseline average). CD-S indicates conventional drilling with straight burs; CD-T, conventional drilling with tapered burs, OD, osseodensification; T1, temperature at crestal level; T2, temperature at midroot level; T3, temperature at apical level.
Example of temperature changes during osteotomy site preparation using osseodensification burs (a) versus conventional tapered implant burs (b). Arrows indicate the time when each bur is used. A stepwise increase in the temperature of the surrounding bone is noted when greater diameters of Densah burs are used during osseodensification.
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