Evaluation of maxillary first molar rotation during direct miniscrew-supported maxillary canine retraction: a before-and-after study

Background Extraction of the first premolar followed by canine retraction into the extraction space is a common treatment in orthodontics. Molar rotation occurs when they are used as anchorage units for the canine distalization. The aim of this single-arm clinical trial was to evaluate the maxillary first molar rotation during maxillary canine retraction with elastic power chains and direct miniscrew anchorage. Results The mean difference between pre-retraction and post-retraction molar rotation was 1.89° ± 0.6 which was statistically insignificant. Conclusion The use of miniscrews for direct anchorage can eliminate unwanted rotation of the maxillary first molars during canine retraction. Trial registration ClinicalTrials.gov, NCT04887974. Registered on May 6, 2021- Retrospectively registered https://clinicaltrials.gov/ct2/show/NCT04887974?id=NCT04887974&draw=2&rank=1.

The Significance of Utilizing A Corticotomy on Periodontal and Orthodontic Outcomes: A Systematic Review and Meta-Analysis

Purpose: This systematic review compares the clinical and radiographic outcomes for patients who received only a corticotomy or periodontal accelerated osteogenic orthodontics (PAOO) with those who received a conventional orthodontic treatment. Methods: An electronic search of four databases and a hand search of peer-reviewed journals for relevant articles published in English between January 1980 and June 2021 were performed. Human clinical trials of ≥10 patients treated with a corticotomy or PAOO with radiographic and/or clinical outcomes were included. Meta-analyses were performed to analyze the weighted mean difference (WMD) and confidence interval (CI) for the recorded variables. Results: Twelve articles were included in the quantitative analysis. The meta-analysis revealed a localized corticotomy distal to the canine can significantly increase canine distalization (WMD = 1.15 mm, 95% CI = 0.18–2.12 mm, p = 0.02) compared to a conventional orthodontic treatment. In addition, PAOO also showed a significant gain of buccal bone thickness (WMD = 0.43 mm, 95% CI = 0.09–0.78 mm, p = 0.01) and an improvement of bone density (WMD = 32.86, 95% CI = 11.83–53.89, p = 0.002) compared to the corticotomy group. Conclusion: Based on the findings of the meta-analyses, the localized use of a corticotomy can significantly increase the amount of canine distalization during orthodontic treatment. Additionally, the use of a corticotomy as a part of a PAOO procedure significantly increases the rate of orthodontic tooth movement and it is accompanied by an increased buccal bone thickness and bone density compared to patients undergoing a conventional orthodontic treatment.

Mini-implant supported canine retraction with micro-osteoperforation: A split-mouth randomized clinical trial

ABSTRACT Objectives: To investigate, using a split-mouth randomized clinical design, the effect of micro-osteoperforation (MOP) on mini-implant supported canine retraction using fixed appliances. Materials and Methods: Thirty subjects (seven males and 23 females) with a mean age of 22.2 (3.72) years were randomized into three canine retraction groups: Group 1 (MOP 4-weekly maxilla/8-weekly mandible; n = 10); Group 2 (MOP 8-weekly maxilla/12-weekly mandible; n = 10) and Group 3 (MOP 12-weekly maxilla/4-weekly mandible; n = 10) measured at 4-week intervals over 16 weeks. Subjects also completed pain (5-point Likert scale) and pain impact (Visual Analogue Scale) questionnaires. The primary outcome was the amount of canine retraction over 16 weeks at MOP (experimental) and non-MOP (control) sites. Results: Mean overall canine retraction was 4.16 (1.62) mm with MOP and 3.06 (1.64) mm without. After adjusting for differences between jaws, all MOP groups exhibited significantly higher canine distalization than the control group: 0.89 mm more (95% confidence interval [CI] = 0.19 to 1.59 mm; P = .01) in the MOP-4 group, 1.08 mm more (95% CI = 0.49 to 1.68 mm; P = .001) in the MOP-8 group and 1.33 mm more (95% CI = 0.55 to 2.10 mm; P = .002) in the MOP-12 group. All subjects reported pain associated with MOP with 60% classifying it as moderate and 15% severe. The main impact of this reported pain was related to chewing and speech. Conclusions: MOP can increase overall mini-implant supported canine retraction over a 16-week period of observation but this difference is unlikely to be clinically significant.

EFFECTS OF MECHANICAL VIBRATION FORCE ON TOOTH MOVEMENT; FINITE ELEMENT ANALYSIS

Objective: The aim of this finite element study was to assess the effect of mechanical vibration force on tooth movement, stress distribution and velocity. Methods: A 3D model was created using CBCT image of a patient with class 2 malocclusion. Three different analyses were performed on a single model where upper first premolars were extracted. At canine distalization stage; 150 gf, 150 gf and 30 Hz (0.2 N), 150 gf and 111 Hz (0.06 N) were applied to canine. The first moment effect of force and vibration were evaluated using the Algor Fempro finite element analysis program. Stress and displacement distribution were investigated comparatively. Results: It was observed that the maximum displacement occurred in the second analysis (150 gf-30 Hz), while lower displacement was seen in the third analysis (150 gf-111 Hz), and the lowest amount of displacement was in the first analysis (150 gf). While only force application caused extrusion of the tooth, linear and vibration forces together caused intrusion. In the first analysis canine rotated in the distovestibule direction, but in the second and third analysis, canine showed distopalatal rotation. Conclusion: It was concluded that in a certain range, mechanical vibration force may have accelerated tooth movement.

EFFECTS OF MECHANICAL VIBRATION FORCE ON TOOTH MOVEMENT; FINITE ELEMENT ANALYSIS

Objective: The aim of this finite element study was to assess the effect of mechanical vibration force on tooth movement, stress distribution and velocity. Methods: A 3D model was created using CBCT image of a patient with class 2 malocclusion. Three different analyses were performed on a single model where upper first premolars were extracted. At canine distalization stage; 150 gf, 150 gf and 30 Hz (0.2 N), 150 gf and 111 Hz (0.06 N) were applied to canine. The first moment effect of force and vibration were evaluated using the Algor Fempro finite element analysis program. Stress and displacement distribution were investigated comparatively. Results: It was observed that the maximum displacement occurred in the second analysis (150 gf-30 Hz), while lower displacement was seen in the third analysis (150 gf-111 Hz), and the lowest amount of displacement was in the first analysis (150 gf). While only force application caused extrusion of the tooth, linear and vibration forces together caused intrusion. In the first analysis canine rotated in the distovestibule direction, but in the second and third analysis, canine showed distopalatal rotation. Conclusion: It was concluded that in a certain range, mechanical vibration force may have accelerated tooth movement.