Comparison of mean canine retraction between healed and recently extracted site: A single center, randomized control trial

Effectiveness of low-intensity electrical current in accelerating the en-masse retraction of the upper anterior teeth following first-premolar extraction in young adult patients with Class II division 1 malocclusion: A randomized controlled clinical trial

INTRODUCTION

Many efforts have been made to shorten fixed appliance orthodontic treatment time by accelerating the rate of tooth movement. Low-intensity electrical stimulation (LIES) is one of the proposed physical methods that has not yet been well studied in the medical literature. This study aimed to evaluate the effectiveness of LIES in accelerating orthodontic tooth movement in cases of en-mass retraction of the upper anterior teeth.

METHODS

Patients who attended the Department of Orthodontics at the Faculty of Dentistry, University of Damascus, between September 2019 and February 2021, for treatment were carefully checked. All patients who met the eligibility criteria were invited to participate in this RCT. Young adult patients having class II division I malocclusion were equally and randomly assigned into the low-intensity electrical stimulation group (LIES), and traditional en-masse retraction group (TRAD). The mini-implants assisted en-masse retraction technique was used to close the extracted upper first premolar spaces in both groups. NiTi closed coil springs (250g/side) were used. Electrical stimulation of 15-20μA for each tooth was applied on the upper anterior teeth using a recently developed intraorally removable device in the LIES group. The primary outcome was the en-masse retraction rate, the secondary outcomes were changes in the first molar position, intermolar width, and intercanine width. These outcomes were measured on the digital photographs of the maxilla cast using the Image J program. Two-sample t-test with Bonferroni's correction was utilized to explore any significant differences between the two groups in all studied variables.

RESULTS

Of the 168 patients examined by the researcher, 38 patients with Class II division I malocclusion (30 females and 8 males; mean age: 21.1±2.31 years) were finally recruited in this RCT. The overall en-masse retraction rate was significantly greater in the LIES group compared to the TRAD group (1.02±0.08, 0.73±0.04mm/month respectively; P<0.001). In addition, the monthly rate of space closure was significantly greater in this group at all evaluation times (P<0.001). A small increase was noted in the intercanine width (1.60±0.27, and 1.65±0.33mm respectively). Negligible changes were noted in the first molar positions and intermolar width, with insignificant differences between the two groups.

CONCLUSIONS

LIES according to the protocol applied in this trial accelerated the upper anterior teeth en-masse retraction rate by approximately 28% compared to the traditional en-masse retraction method. While this acceleration was statistically significant, may not have substantial clinical implications.

REGISTRATION

This trial protocol was registered in the Clinical Trials database (ClinicalTrials.gov NCT05350280).

The effect of early versus delayed space closure on the rate of orthodontic tooth movement: a systematic review and meta-analysis

BACKGROUND

Orthodontic space closure of extraction sites can be initiated early, within 1-week post-extraction, or it can be delayed for a month or more.

OBJECTIVE

This systematic review aimed to evaluate the effect of early versus delayed initiation of space closure after tooth extraction on the rate of orthodontic tooth movement.

SEARCH METHODS

Unrestricted search of 10 electronic databases was conducted until September 2022.

SELECTION CRITERIA

Randomized controlled trials (RCTs) investigating the initiation time of space closure of extraction sites in patients undergoing orthodontic treatment were included.

DATA COLLECTION AND ANALYSIS

Data items were extracted using a pre-piloted extraction form. The Cochrane's risk of bias tool (ROB 2.0) and the Grading of Recommendations, Assessment, Development, and Evaluation approach were used for quality assessment. Meta-analysis was undertaken if there are at least two trials reporting the same outcome.

RESULTS

Eleven RCTs met the inclusion criteria. Meta-analysis revealed that early canine retraction resulted in a statistically significant higher rate of maxillary canine retraction when compared to delayed canine retraction [mean difference (MD); 0.17 mm/month, 95% CI: 0.06 to 0.28, P = 0.003, 4 RCTs, moderate quality]. Duration of space closure was shorter in the early space closure group, but not statistically significant (MD; 1.11 months, 95% CI: -0.27 to 2.49, P = 0.11, 2 RCTs, low quality). The incidence of gingival invaginations was not statistically different between early and delayed space closure groups (Odds ratio; 0.79, 95% CI: 0.27 to 2.29, 2 RCTs, P = 0.66, very low quality). Qualitative synthesis found no statistically significant differences between the two groups regarding anchorage loss, root resorption, tooth tipping, and alveolar bone height.

CONCLUSIONS

Based on the available evidence, early traction within the first week after tooth extraction has a minimal clinically significant effect on the rate of tooth movement compared to delayed traction. Further high-quality RCTs with standardized time points and measurement methods are still needed.

REGISTRATION

PROSPERO (CRD42022346026).

Effects of Flapless Laser Corticotomy in Upper and Lower Canine Retraction: A Split-mouth, Randomized Controlled Trial

Aim One of the major difficulties in orthodontic treatment is the lengthy course of therapy, particularly in situations involving extractions. Hence, various methods for accelerating tooth movement rate had been devised. Flapless corticotomy is one of those methods. This study aimed to evaluate the effects of flapless laser corticotomy (FLC) compared to the conventional retraction (CR) method on the rate of canine retraction. Methods A split-mouth, randomized controlled trial included 56 canines from 14 patients (12 females and two males) with a mean age of 20.4 ± 2.5 years, who were complaining of bimaxillary protrusion requiring extraction of four premolars. All canines were randomly assigned to four groups (maxillary FLC, maxillary control CR, mandibular FLC, and mandibular control CR). Randomization was performed by creating two equal, random computer-generated lists with a 1:1 allocation ratio-one list for the right side and one for the left. The allocation concealment was achieved using opaque sealed envelopes until the time of intervention. FLC was applied on the experimental sides before canine retraction by drilling six holes penetrating 3 mm into the bone on the mesial and distal sides of the canines. Subsequently, all canines were retracted employing closed coil springs to deliver a force of 150 g using indirect anchorage from temporary anchorage devices (TADs). All canines were assessed at T0 (before retraction), T1 (one month after retraction), T2 (two months), and T3 (three months) using three-dimensional (3D) digital models. Additionally, canine rotation, molar anchorage loss assessed using 3D digital models, root resorption assessed using cone beam computed tomography (CBCT), probing depth, plaque, gingival indices, and pulp vitality were all evaluated as secondary outcomes. It was possible to blind only the outcome analysis expert (single-blinded). Results The measurements of canine retraction during the follow-up period from T0 to T3 were 2.46 ± 0.80 mm and 2.55 ± 0.79 mm in maxillary FLC and control groups, respectively, and 2.44 ± 0.96 mm and 2.31 ± 0.95 mm in mandibular FLC and control groups, respectively. The results demonstrated a statistically non-significant difference in the distance of canine retraction between the FLC and control groups at all time points. Moreover, no differences were observed between groups in canine rotation, molar anchorage loss, root resorption, probing depth, plaque, gingival indices, and pulp vitality (p > 0.05). Conclusion In the FLC procedure performed in this study, the rate of upper and lower canine retraction could not be accelerated and no significant differences were observed between FLC and control groups in canine rotation, molar anchorage loss, root resorption, periodontal condition, and pulp vitality.

A comparative assessment of the amount and rate of orthodontic space closure toward a healed vs recent lower premolar extraction site

OBJECTIVES

To investigate and compare the amount and rate of space closure and tooth tipping during orthodontic space closure toward a recent vs healed first premolar extraction site.

MATERIALS AND METHODS

The mandibular arches of 23 patients were included. Treatment plans included lower first premolar extractions. After reaching 0.019 × 0.025-inch stainless-steel archwires (SSAW), patients were subdivided into two groups (Group 1: space closure was carried out toward a healed first premolar extraction space and Group 2: space closure was carried out immediately after first premolar extraction). Elastomeric power chain from second molar to second molar was used to close lower extraction spaces. The following time points were defined: T1: just before space closure; T2-T4: 1-3 months after initial space closure. Records consisted of dental study models. The amount and rate of extraction space closure were evaluated at each time point.

RESULTS

In Group 1 (healed socket), a total amount of 1.98 mm (coronally) and 1.75 mm (gingivally) of space closure was achieved. The rate of space closure was 0.66 mm/month coronally and 0.58 mm/month gingivally. In Group 2 (recent socket), the total amount of space closure was 3.02 mm coronally and 2.68 mm gingivally. The rate of space closure was 1.01 mm/month coronally and 0.89 mm/month gingivally. Differences between the two groups were significant (P < .01). Tipping of adjacent teeth during space closure was similar in both groups (P > .05).

CONCLUSIONS

In the lower arch, the amount and rate of space closure toward a recent extraction site were higher than that toward a healed extraction socket with similar tipping of teeth in both groups.