Korean J Orthod.  2011 Oct;41(5):354-360. 10.4041/kjod.2011.41.5.354.

The effects of different pilot-drilling methods on the mechanical stability of a mini-implant system at placement and removal: a preliminary study

• Cho IS
• Choo H
• Kim SK
• Shin YS
• Kim DS
• Kim SH
• Chung KR
• Huang JC

• KMID: 1975392
• DOI: http://doi.org/10.4041/kjod.2011.41.5.354

Abstract

OBJECTIVE
To investigate the effects of different pilot-drilling methods on the biomechanical stability of self-tapping mini-implant systems at the time of placement in and removal from artificial bone blocks.
METHODS
Two types of artificial bone blocks (2-mm and 4-mm, 102-pounds per cubic foot [102-PCF] polyurethane foam layered over 100-mm, 40-PCF polyurethane foam) were custom-fabricated. Eight mini-implants were placed using the conventional motor-driven pilot-drilling method and another 8 mini-implants were placed using a novel manual pilot-drilling method (using a manual drill) within each of the 2-mm and 4-mm layered blocks. The maximum torque values at insertion and removal of the mini-implants were measured, and the total energy was calculated. The data were statistically analyzed using linear regression analysis.
RESULTS
The maximum insertion torque was similar regardless of block thickness or pilot-drilling method. Regardless of the pilot-drilling method, the maximum removal torque for the 4-mm block was statistically higher than that for the 2-mm block. For a given block, the total energy at both insertion and removal of the mini-implant for the manual pilot-drilling method were statistically higher than those for the motor-driven pilot-drilling method. Further, the total energies at removal for the 2-mm block was higher than that for the 4-mm block, but the energies at insertion were not influenced by the type of bone blocks.
CONCLUSIONS
During the insertion and removal of mini-implants in artificial bone blocks, the effect of the manual pilot-drilling method on energy usage was similar to that of the conventional, motor-driven pilot-drilling method.

Keyword

Anchorage; Implant design; Surface treatment; Orthodontic mini-implant

MeSH Terms

Foot
Linear Models
Polyurethanes
Torque
Polyurethanes

Figure

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  Fig. 1 Motor-driven pilot-drilling method. A, A 1.5 mm diameter guide drill; B, pilot drilling using a guide drill; C, C-implant placement using a hand driver.

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  Fig. 2 Manual pilot-drilling method using a hand drill. A, A 1.5 mm diameter hand drill; B and C, hand-drilling on the planned positions of a mini-implant placement; D, removal of a hand drill with a counter clockwise rotation; E and F, C-implant placement on the pilot hole; G, after adaption of the head part.

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  Fig. 3 A, Motor-driven pilot-drilling procedure on a artificial bone block; B, a hand drill for manual pilot drilling; C and D, a surgical engine implant system for the insertion of mini-implants and measurement of insertion and removal torques.

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  Fig. 4 Graph showing the insertion torques with respect to the elapsed time. MD, Motor-driven pilot drilling; HD, manual pilot-drilling using a hand drill.

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  Fig. 5 Graph showing the removal torques with respect to the elapsed time. MD, Motor-driven pilot drilling; HD, manual pilot-drilling using a hand drill.

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