There is much interest in interventions to shortening the duration of orthodontic treatment. In cases that require tooth extraction this is typically carried out at the start of treatment. However, there is some debate as to whether space closure should be undertaken immediately after extraction. Initiating space closes on the same day as extractions or up to 38 days after is considered early with initiation after 38 days as delayed.
The aim of this review was to evaluate the effect of early versus delayed initiation of space closure after tooth extraction on the rate of orthodontic tooth movement.
Methods
A protocol was registered in the PROSPERO database. Searches were conducted in the Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, Embase, Scopus, Web of Science, China National Knowledge Infrastructure (CNKI), and Latin America and the Caribbean Literature on Health Sciences (LILACS) OpenGrey, Google Scholar (First 250 results) and ProQuest databases with no restrictions. Randomised controlled trials (RCTs) investigating the initiation time of space closure of extraction sites in patients undergoing orthodontic treatment were considered.
Two reviewers independently and in duplicate screened and selected studies extracted data and assessed risk of bias using the Cochrane risk of bias tool (RoB2). Continuous outcomes were measured using Mean difference (MD) and dichotomous outcomes with odds ratios (OR)with 95% confidence intervals (CI). Meta-analysis was undertaken if there are at least two trials reporting the same outcome.
Results
- 11 RCTs (7 split mouth, 3 parallel, 1 mixed) involving a total of 337 patients were included.
- 4 studies were conducted in China and one each in Austria, Germany, India, Jordan, Nigeria, Pakistan and Switzerland.
- All patients underwent fixed orthodontic treatment.
- Extraction sites were first or second premolars in maxilla/mandible.
- Early space closure was done for 357 extraction sites (267 maxillary; 90 mandibular), and delayed closure for 343 extraction sites (263 maxillary; 80 mandibular).
- 7 studies were considered to be at high risk of bias and 4 as having some concerns.
- Meta-analysis (4 RCTs) found a statistically higher overall rate of maxillary canine retraction post-extraction by 0.17 mm/month (95% CI: 0.06 to 0.28) favouring the early traction group. However, the prediction interval includes the value of no effect (−0.34 to 0.68).
- Mandibular canine retraction, space closure, de-crowding and molar anchorage loss were reported in single studies.
- Meta-analysis (2 RCTs) found no statistically significant difference in the duration of space closure between early and delayed maxillary canine retraction arms, MD= 1.11 months (95%CI: −0.27 to 2.49).
- Meta-analysis (2 RCTs) found no statistically significant difference in the incidence of gingival invaginations after early versus delayed traction toward extraction sites, OR= 0.79 (95%CI: 0.27 to 2.29).
- Root resorption and the alveolar bone height following early versus delayed maxillary canine traction was investigated by 4 RCTs with no differences being found.
Conclusions
The authors concluded: –
….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.
Comments
The authors published their protocol on PROSPERO and searched a broad range of databases with no restrictions. Eleven RCTs were identified but they are small with 7 being at high risk of bias and none at low risk. A broad range of outcomes were considered in the studies with some only in single studies. Maxillary canine retraction was the most common outcome being reported in (6 studies). Although the meta-analysis indicated a benefit from early retraction the prediction interval suggests no benefit. The authors also highlight the variation in the initiation times in both groups. While future well conducted and reported trials of appropriate size are required these need to be conducted using a common outcomes set. Outcomes should also include patient-reported outcome measures (PROMs) as none were included in any of the studies included in this review.
Links
Primary Paper
Daraqel B, Mheissen S, Li J, Khan H, Allan S, Zheng L. The effect of early versus delayed space closure on the rate of orthodontic tooth movement: a systematic review and meta-analysis. Eur J Orthod. 2023 May 18:cjad015. doi: 10.1093/ejo/cjad015. Epub ahead of print. PMID: 37203234.
Other references
Dental Elf – 23rd Jun 2023
Non‐surgical procedures to accelerate orthodontic tooth movement
