Biomechanical evaluation of undersized drilling on implant biomechanical stability at early implantation times.
OBJECTIVE
The present study evaluated the effect of different drilling dimensions (undersized, regular, and oversized) in the insertion and removal torques of dental implants in a beagle dog model.


METHODS
Six beagle dogs were acquired and subjected to bilateral surgeries in the radii 1 and 3 weeks before euthanasia. During surgery, 3 implants, 4 mm in diameter by 10 mm in length, were placed in bone sites drilled to 3.2 mm, 3.5 mm, and 3.8 mm in final diameter. The insertion and removal torque was recorded for all samples. Statistical analysis was performed by paired t tests for repeated measures and by t tests assuming unequal variances (all at the 95% level of significance).


RESULTS
Overall, the insertion torque and removal torque levels obtained were inversely proportional to the drilling dimension, with a significant difference detected between the 3.2 mm and 3.5 mm relative to the 3.8 mm groups (P < 0.03). Although insertion torque-removal torque paired observations was statistically maintained for the 3.5 mm and 3.8 mm groups, a significant decrease in removal torque values relative to insertion torque levels was observed for the 3.2 mm group. A different pattern of healing and interfacial remodeling was observed for the different groups.


CONCLUSIONS
Different drilling dimensions resulted in variations in insertion torque values (primary stability) and stability maintenance over the first weeks of bone healing.
Department of Biomaterials and Biomimetics, New York University, New York, NY, USA.
Paulo G
PG
Coelho
Charles
C
Marin
Hellen S
HS
Teixeira
Felipe E
FE
Campos
Julio B
JB
Gomes
Fernando
F
Guastaldi
Rodolfo B
RB
Anchieta
Lucas
L
Silveira
Estevam A
EA
Bonfante
D000818:Animals; D001696:Biomechanical Phenomena; D003758:Dental Implantation, Endosseous / Q000295:instrumentation / Q000379:methods*; D015921:Dental Implants; D017267:Dental Prosthesis Design; D017268:Dental Prosthesis Retention; D004285:Dogs; D008297:Male; D023421:Models, Animal; D016348:Osseointegration / Q000502:physiology; D010027:Osteotomy / Q000295:instrumentation; D013314:Stress, Mechanical; D013499:Surface Properties; D013977:Tibia / Q000601:surgery; D013997:Time Factors; D019415:Torque
D015921:Dental Implants