Summary
Background/Objective
To quantify the expected amount of orthodontically induced root resorption (OIRR) after orthodontic intrusion and assess the treatment-related factors.
Search methods and eligibility criteria
Six electronic databases and partial grey literature were searched without limitations regarding language or publication year until April 2020. Randomized clinical trials and non-randomized prospective and retrospective studies evaluating root resorption after orthodontic intrusion were included.
Data collection and analysis
Risk of bias (RoB) assessment was performed with the Cochrane Collaboration’s RoB Tool 2.0 and ROBINS-I tool for the randomized and non-randomized studies, respectively. The data were combined into two random-effects meta-analyses estimating OIRR following orthodontic intrusion. One evaluated OIRR in the anterior region, while the other assessed OIRR in the posterior region. Sub-group analyses regarding the type of mechanics applied, duration of intrusion, amount of force, and sensitivity analysis of the study design and imaging examinations were also performed. The certainty of the evidence was assessed through the Grade of Recommendation, Assessment, Development, and Evaluation (GRADE) approach.
Results
The qualitative analysis included 14 studies; however, the meta-analysis was performed with 7 records. The random-effects model assumes that 0.72 mm [95% confidence interval (CI): 0.16 to 1.28] and 0.41 mm (95% CI: −0.24 to 1.07) of OIRR should be expected in the incisors and the molars, respectively. Sub-group analyses showed that the assessed treatment-related factors presented minimum impact in OIRR after orthodontic intrusion. The GRADE resulted in moderate and low certainty regarding the meta-analysis.
Limitations
The major limitation of the present meta-analysis is that OIRR can be affected by several factors, some of which are assessed in this review.
Conclusions
Orthodontic intrusion, evaluated as an isolated mechanic, caused less than 1 mm of OIRR, which is within the acceptable limits for clinical implication. Treatment-related factors did not show a significant influence on OIRR.
Registration
This review was registered in PROSPERO, protocol number CRD42018098495.
Summary
Objectives
To compare posterior crossbite correction frequency and dentoalveolar changes of the expander with differential opening (EDO) and the fan-type expander (FE).
Trial design
Two-arm parallel randomized controlled trial.
Methods
Forty-eight patients from 7 to 11 years of age were allocated into two groups. Twenty-four patients were treated with the EDO and 24 patients were treated with the FE. Block randomization was performed. The study was single blind. Digital dental models were acquired before treatment and 6 months after rapid maxillary expansion. The primary outcomes were crossbite correction rate and maxillary arch width changes. Secondary outcomes were interincisal diastema, arch perimeter, length, size and shape, and mandibular dental arch changes.
Results
The final sample comprised 24 patients (13 female and 11 male; mean initial age of 7.62 years) in the EDO group and 24 patients (14 female and 10 male; mean initial age of 7.83 years) in the FE group. The crossbites were corrected in 100 per cent of subjects from EDO group and in 75 per cent of patients in FE group. EDO showed greater increases in maxillary intermolar region (P < 0.001), while the FE demonstrated greater increases in the intercanine distance (P = 0.008). Increase in mandibular inter-first permanent molar distance was slightly greater in the EDO group (mean difference of 0.8 mm). Changes in arch length and perimeter were similar in both groups. Both expanders changed the maxillary arch shape. The post-treatment arch shape was larger in the anterior region for FE and in the posterior region in the EDO group.
Harms
Discomfort during activation was reported by 54 per cent of the participants. A temporary change in the nasal bridge was reported by one patient from FE group.
Conclusions
Maxillary arch width and shape changes were distinct between the EDO and the FE. Greater transversal increases of the anterior and posterior regions were observed for the FE and the EDO, respectively. A slightly greater mandibular spontaneous expansion was observed for the EDO only at the molar region.
Trial registration
NCT03705871.
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