• The korean journal of orthodontics
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• v.18 no.1 s.25
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• pp.25-53
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• 1988

Retraction of canines represents a fundamental stage in a considerable number of orthodontic treatment. Correct position of the canine after retraction is most important for function, stability, and esthetics. The purpose of this study was to investigate the stress in the periodontal tissue at the initial phase during canine retraction using various types of sectional retraction springs, by finite element method. Three dimensional model of tooth, periodontal ligament, bone and eight springs were simulated and tested. The following results were obtained. 1. In sectional retraction springs, increasing number of helix and the closed loop in preference to the open loop provided an decrease in horizontal force. Without angulating the arms of spring, the T-loop revealed the highest Moment-to-force ratio. 2. The Moment-to-force ratio raised by angulating mesial and distal arms of spring, but very large horizontal force was applied to canine. 3. When optimal force and optimal moment was applied to canine, the stress induced was homogeneous and the difference of stress value from cervix to the apex was little.

• The korean journal of orthodontics
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• v.48 no.3
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• pp.200-211
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• 2018

The aim of this systematic review was to evaluate the effectiveness and complications of corticotomy and piezocision in canine retraction. Five electronic databases (PubMed, SCOPUS, Web of Science, Embase, and CENTRAL) were searched for articles published up to July 2017. The databases were searched for randomized control trials (RCTs), with a split-mouth design, using either corticotomy or piezocision. The primary outcome reported for canine retraction was either the amount of tooth movement, rate of tooth movement, or treatment time. The secondary outcome was complications. The selection process was based on the PRISMA guidelines. A risk of bias assessment was also performed. Our search retrieved 530 abstracts. However, only five RCTs were finally included. Corticotomy showed a more significant (i.e., 2 to 4 times faster) increase in the rate of tooth movement than did the conventional method. For piezocision, both accumulative tooth movement and rate of tooth movement were twice faster than those of the conventional method. Corticotomy (with a flap design avoiding marginal bone incision) or flapless piezocision procedures were not detrimental to periodontal health. Nevertheless, piezocision resulted in higher levels of patient satisfaction. The main limitation of this study was the limited number of primary research publications on both techniques. For canine retraction into the immediate premolar extraction site, the rate of canine movement after piezocision was almost comparable to that of corticotomy with only buccal flap elevation.

• The korean journal of orthodontics
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• v.36 no.4
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• pp.308-320
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• 2006

Rapid canine retraction, first introduced by Liou, is a distraction osteogenesis applied to the periodontal ligament tissue. Rapid tooth movement was facilitated by establishing minimal bony resistance on the distal surface of the canine by socket preparation and by osteogenesis on the mesial side in response to the periodontal distraction. Since undesired buccal tipping or extrusion of the canine during retraction tends to occur, it is crucial to maintain the firm path of movement and the axis of the canine during retraction. In order to improve the predictability of the canine movement, lingually extended distraction screws with heavy labial guiding wires were designed. Prefabricated plastic canine models for the estimation of socket depth and miniscrew implants for anchorage reinforcement were also devised. Applying these devices to a female patient with Class II anterior protrusion, the whole treatment was effectively finished in 13 months. Loss of vitality or periodontal problems did not occur throughout treatment, and stable occlusion was maintained during 10 months of retention. This case report demonstrates that a predictable rapid canine retraction can be achieved through the use of this modified technique.

• The korean journal of orthodontics
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• v.49 no.6
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• pp.381-392
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• 2019

Objective: The objective of this two-arm parallel trial was to compare the type of tooth movement during en masse retraction of the maxillary anterior teeth using labial versus lingual biocreative therapy. Methods: Twenty-eight subjects were randomized in a 1 : 1 ratio to either the labial or lingual group. En masse anterior retraction was performed using labial biocreative therapy in group A and lingual biocreative therapy in group B. Cone beam computed tomography scans were taken before and after retraction and the primary outcome was the type of tooth movement during anterior retraction. Data were analyzed using paired t-tests for comparisons within each group and independent-sample t-test for comparison of the mean treatment changes between the two groups. Results: Significant differences were found between the two groups in relation to the type of tooth movement (labiolingual inclination of the central incisor; mean difference, $5.85{\pm}1.85^{\circ}$). The canine showed significant distal tipping in the lingual group (mean difference, $6.98{\pm}1.25^{\circ}$). The canine was significantly more intruded in the lingual group (mean difference, $1.67{\pm}0.49mm$). Good anchorage control and significant soft tissue changes occurred in both groups. No serious adverse effects were detected. Conclusions: With a 10-mm retraction hook, the labial biocreative technique with the reverse curve overlay provided anterior retraction with good torque control, while in the lingual group, anterior retraction occurred with controlled tipping movement with significant distal tipping and intrusion of the canine (trial registration: The trial was registered at ClinicalTrials.gov [NCT03239275]).

• The korean journal of orthodontics
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• v.26 no.4
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• pp.341-348
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• 1996

The efficiency of maxillary canine retraction by means of sliding mechanics along an 0.016 continuous labial arch and an 0.009 inch in diameter with a lumen of 0.030 inch NiTi closed coil spring was compared with that using the same NiTi closed coil spring and Molar Anchoring Spring(MAS) which was designed by author. MAS was made of .017" X .025" TMA wire and was given 60 degree tip-back bend on the wire close to the molar tube. This study was designed to investigate molar and canine root control during retraction into an extraction site with continuous arch wire system. Two techniques were tested with a continuous arch model embedded in a photoelastic resin. A photoelastic model was employed to visualize the effects of forces applied to canine and molar by two retraction mechanics. With the aid of polarized light, stresses were viewed as colored fringes. The photoelastic overview of the upper right quadrant showed that stress concentrations were observed in its photoelastic model. The obtained results were as follows. 1. Higher concentration of compression can be seen clearly at the distal curvature of the canine and mesial curvature of the molar and premolar when NiTi closed coil spring was applied only, which means severe anchorage loss of the molar and uncontrolled tipping of the canine. 2. The least level compression was presented at the mesial root area of the molar and premolar, and mesial root area of the canine when NiTi closed coil spring and MAS were used simultaneously. Especially mesial alveolar crest region of the canine was shown moderate level of compression that means MAS can be used as a appliance for anchorage control and prevention of canine extrusion and uncontrolled tipping during canine retraction.

• The korean journal of orthodontics
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• v.51 no.3
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• pp.157-165
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• 2021

Objective: This study aimed to identify the clinical effectiveness of two different penetration depths of micro-osteoperforations (MOPs) on the rate of orthodontic tooth movement. Methods: Twenty-four patients requiring the removal of the upper first premolar teeth were selected and randomly divided into two groups. The control group participants did not undergo MOPs. Participants in the experimental group underwent three MOPs each at 4-mm (MOP-4) and 7-mm (MOP-7) depths, which were randomly and equally performed to either the left or right side distal to the canine. The retraction amount was measured on three-dimensional digital models on the 28th day of retraction. MOP-related pain was measured using a visual analog scale (VAS). Between-group statistical differences in the VAS scores were determined using an independent t-test and those in canine retraction were determined using analysis of variance and post-hoc Tukey test. Results: No significant difference was found between the MOP-4 (1.22 ± 0.29 mm/month) and MOP-7 (1.29 ± 0.31 mm/month) groups in terms of the canine retraction rate. Moreover, both the groups demonstrated a significantly higher canine movement than the control group (0.88 ± 0.19 mm/month). MOPs did not significantly affect the mesialization of the posterior teeth (p > 0.05). Moreover, the pain scores in the MOP-4 and MOP-7 groups were similar and showed no statistically significant difference. Conclusions: Three MOPs with a depth of 4 mm can be performed as an effective method to increase the rate of tooth movement. However, three MOPs with depths of 4-7 mm does not additionally enhance tooth movement.

• The korean journal of orthodontics
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• v.32 no.3 s.92
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• pp.165-174
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• 2002

The purpose of this study was to compare on masse retraction of six anterior teeth with separate canine retraction in the amount of the anchorage loss and the retraction of the anterior teeth. The subjects consisted of 30 adult female patients with Angle Class 1 malocclusions who were treated by .022' straight wire appliance with 4 first permolar extraction. They were composed of two groups. Group 1 consisted of 15 subjects, whose six anterior teeth were retracted by on masse retraction. Group 2 consisted of 15 subjects, whose canines were retracted separately. Pre-treatment and post-treatment lateral cephalometric radiographs were analyzed. All data were processed statistically with independent samples t-test, and the conclusions were as follows. 1. There was no significant difference in the amount of the anchorage loss between two groups(p>0.05). 2. There was no significant difference in the amount of the retraction of the anterior teeth between two groups(p>0.05). 3. There was a significant difference in the amount of the inclinational change of the upper incisors between two groups. It was greater in Group 2. 4. There was a significant difference in the vertical positional change of the upper incisal edges between two groups. The upper incisal edges in Group 2 were more extruded than Group 1 by about 1mm. 5. There was no significant difference in the vertical positional change of the root apex of the upper incisors between two groups(p>0.05). And there was no significant difference in the vertical positional change of the upper molar(p>0.05).

• 대한치과교정학회:학술대회논문집
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• 1997.11a
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• pp.51.2-51.2
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• 1997

• The Journal of the Korean dental association
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• v.16 no.9 s.112
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• pp.640-640
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• 1978

• The Journal of the Korean dental association
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• v.28 no.3 s.250
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• pp.229-229
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• 1990