Abstract
Objective
The purpose of this study was to compare self-drilling orthodontic mini-implants of different surfaces, namely, machined (untreated), etched (acid-etched), RBM (treated with resorbable blasting media) and hybrid (RBM + machined), with respect to the following criteria: physical appearance of the surface, measurement of surface roughness, and insertion pattern.
Methods
Self-drilling orthodontic mini-implants (Osstem implant, Seoul, Korea) with the abovementioned surfaces were obtained. Surface roughness was measured by using a scanning electron microscope and surface-roughness-testing machine, and torque patterns and vertical loadings were measured during continuous insertion of mini-implants into artificial bone (polyurethane foam) by using a torque tester of the driving-motor type (speed, 12 rpm).
Results
The mini-implants with the RBM, hybrid, and acid-etched surfaces had slightly increased maximum insertion torque at the final stage (p < 0.05). Implants with the RBM surface had the highest vertical load for insertion (p < 0.05). Testing for surface roughness revealed that the implants with the RBM and hybrid surfaces had higher Ra values than the others (p < 0.05). Scanning electron microscopy showed that the implants with the RBM surface had the roughest surface.
Figures and Tables
Fig. 1
Shape and size (mm) of self drilling type orthodontic mini implant (Osstem Implant, Seoul, Korea).
![kjod-41-268-g001](/upload/SynapseData/ArticleImage/0123kjod/kjod-41-268-g001.jpg)
Fig. 2
Surface treated orthodontic mini implants. A, Machined surface; B, etched surface; C, RBM surface; D, hybrid surface. RBM, Resorbable blasting media.
![kjod-41-268-g002](/upload/SynapseData/ArticleImage/0123kjod/kjod-41-268-g002.jpg)
Fig. 3
SEM image of orthodontic mini implants (× 10). A, Machined surface; B, acid etched surface; C, RBM surface; D, hybrid surface. The surface difference between C and D is observed. SEM, Scanning electron microscope; RBM, resorbable blasting media.
![kjod-41-268-g003](/upload/SynapseData/ArticleImage/0123kjod/kjod-41-268-g003.jpg)
Fig. 4
SEM image of orthodontic mini implants (× 50). A, Machined surface; B, acid etched surface; C, RBM surface; D, hybrid surface. C and D have rough surfaces. White box indicates the area of magnification × 500. SEM, Scanning electron microscope; RBM, resorbable blasting media.
![kjod-41-268-g004](/upload/SynapseData/ArticleImage/0123kjod/kjod-41-268-g004.jpg)
Fig. 5
SEM image of orthodontic mini implants (× 500). A, Machined surface; B, acid etched surface; C, RBM surface; D, hybrid surface. The surface difference between A and B is observed. SEM, Scanning electron microscope; RBM, resorbable blasting media.
![kjod-41-268-g005](/upload/SynapseData/ArticleImage/0123kjod/kjod-41-268-g005.jpg)
Fig. 6
The surface roughness of sample 1 of each group of A, machined; B, etched; C, RBM; and D, hybrid mini-implants. RBM, Resorbable blasting media.
![kjod-41-268-g006](/upload/SynapseData/ArticleImage/0123kjod/kjod-41-268-g006.jpg)
Fig. 7
Mean surface roughness (Ra) of surface treated orthodontic mini implants. Groups with the same letters were not significantly different from each other at the level of p < 0.05 (a < b). RBM, Resorbable blasting media.
![kjod-41-268-g007](/upload/SynapseData/ArticleImage/0123kjod/kjod-41-268-g007.jpg)
Fig. 8
Insertion pattern of sample 1 of machined surface group mini-implants. a, Vertical load for insertion (Ncm); b, rotational torque for insertion (Ncm).
![kjod-41-268-g008](/upload/SynapseData/ArticleImage/0123kjod/kjod-41-268-g008.jpg)
Fig. 9
Mean insertion torque patterns of surface treated orthodontic mini implants. RBM, Resorbable blasting media.
![kjod-41-268-g009](/upload/SynapseData/ArticleImage/0123kjod/kjod-41-268-g009.jpg)
Fig. 10
Mean vertical load patterns for insertion of surface treated orthodontic mini implants. RBM, Resorbable blasting media.
![kjod-41-268-g010](/upload/SynapseData/ArticleImage/0123kjod/kjod-41-268-g010.jpg)
Fig. 11
Mean final insertion torque of surface treated orthodontic mini implants. a < b, c, d and b > d (p < 0.05). RBM, Resorbable blasting media.
![kjod-41-268-g011](/upload/SynapseData/ArticleImage/0123kjod/kjod-41-268-g011.jpg)
Fig. 12
Mean maximum vertical load for insertion of surface treated orthodontic mini implants. b > a > c (p < 0.05). Same letters were not significantly different. RBM, Resorbable blasting media.
![kjod-41-268-g012](/upload/SynapseData/ArticleImage/0123kjod/kjod-41-268-g012.jpg)
Table 1
Chemical composition and mechanical properties of orthodontic mini-implant (Ti-6Al-4V alloy)
![kjod-41-268-i001](/upload/SynapseData/ArticleImage/0123kjod/kjod-41-268-i001.jpg)
Table 3
Comparison of mean surface roughness (Ra, µm) of the surface treated orthodontic mini-implants
![kjod-41-268-i003](/upload/SynapseData/ArticleImage/0123kjod/kjod-41-268-i003.jpg)
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