Development of a new implant primary stability parameter: insertion torque revisited.
OBJECTIVE
The aims of the study are to introduce a new parameter to measure primary stability and to evaluate the possible correlations between this parameter and bone density, initial bone-to-implant contact (IBIC), Resonance Frequency Analysis (RFA), and peak insertion torque (IT).


METHODS
The study was performed on three different types of fresh humid bovine bone: type I, type II, and type III. A total of 90 XiVE implants (30 per bone type) were used; implant insertion was performed with a calibrated maximum torque of 70 Ncm at predetermined 30 rpm. The IT data were recorded and exported as a curve; using a trapezoidal integration technique, the area underlying the curve was calculated: this area represents the variable torque work (VTW). Furthermore, peak IT and RFA were recorded; finally IBIC was calculated from histological specimens.


RESULTS
Spearman correlation analysis of the entire sample reveals that VTW presents a significant (p < .01) positive correlation with bone density; a significant (p < .05) positive correlation with IBIC, and a significant (p < .01) positive correlation with all the other primary stability parameters. Spearman correlation analysis of the three different groups show that VTW presents a significant positive correlation with IT in all three types of bone; on the other hand, VTW shows a negative not significant correlation with RFA in bone I, a positive significant correlation in bone II, and a positive not significant correlation in bone III. Furthermore, VTW shows a negative significant correlation with IBIC in bone I and a positive significant correlation in bone II and III.


CONCLUSIONS
Within the limitations of an in vitro study, the VTW seems to be a promising parameter to measure implant primary stability.
Private practitioner, Bologna, Italy private practitioner, Bologna, Italy full professor of Oral Pathology, Dental School, University of Chieti, Chieti, Italy researcher, Dental School, University of Chieti, Chieti, Italy.
Marco
M
Degidi
Giuseppe
G
Daprile
Adriano
A
Piattelli
Giovanna
G
Iezzi
D000818:Animals; D002417:Cattle; D015921:Dental Implants; D014057:Tomography, X-Ray Computed; D019415:Torque
D015921:Dental Implants