Do sand blasted with large grit and acid etched surface treated mini-implants remain stationary under orthodontic forces?

Abstract

Objectives: To determine the positional stability of sand blasted, large grit, and acid-etched (SLA) surface-treated mini-implants (C-implants) used as the exclusive source of anchorage during en masse retraction.

Materials and methods: A retrospective clinical investigation was performed comparing pretreatment cone beam computed tomography (CBCT) images with those taken after en masse retraction of the six anterior teeth. Force was applied to 16 C-implants (1.8 mm in diameter, 8.5 mm in length) placed between the upper second premolars and first molars. Three-dimensional superimposition of CBCT data using mutual information was used to evaluate the positional difference of C-implants between preretraction and postretraction CBCT data.

Results: There was no significant difference in mini-implant position between the preretraction and postretraction CBCT evaluation.

Conclusions: The SLA-coated C-implant provides stationary anchorage as well as stable anchorage during orthodontic tooth movement.

Figures

Figure 1

(A) Intraoral photographs of C-implant dependent en masse retraction (16 years, female). (B) Pretreatment cone beam computed tomography scans were taken before en masse retraction and (C) after retraction. (D) Posttreatment.

Figure 2

Cone beam computed tomography images of registration area for the automated voxel superimposition method. The blue dotted area is the registration area and the brown color box designates the field of view.

Figure 3

Superimposed axial slice images of the anterior cranial base before (gray) and after en masse retraction (red-yellow). The sinus wall and other fine anatomic structures are perfectly registered.

Figure 4

Three-dimensional volume rendering images with axial slice before en masse retraction (left side) and superimposition (right side).

Figure 5

Measuring points of C-implants in the 3D volume rendering images (A) with anatomic structure and (B) without anatomic structure. The tail was determined to be the apex of the C-implant screw part, and imaginary head (Ihead) as between the top of the screw and below 0.5 mm from the top. The XY plane is parallel to the upper occlusal plane, and the YZ plane is parallel to the midsagittal plane.

Figure 6

Variables of 3D superimposition of C-implants between preretraction and postretraction periods. Measurement of C-implant on the X-axis: (+) indicates intrusion and (−) indicates extrusion. Measurements on the Y-axis: (−) indicates mesial and (+) indicates distal movement, and on the Z-axis (−) indicates occlusal and (+) indicates cervical movement.