title: Orthodontic treatment for crowded teeth in children
Creators: name: Janjua Sharif, FN
Publisher: name: University of Liverpool Repository
Year: 2017

description: Background: Crowded teeth develop when there is not enough space in the jaws into which the teeth can erupt. This gives the patient crooked or wonky teeth and cause them to present for treatment. Crowding can affect the baby teeth (primary dentition) and/or the adult teeth (permanent dentition). Crowding tends to increase with age, especially in the lower jaw, so that only a third of adults have well aligned lower front teeth (incisors)1. Crowding of the adult teeth can also occur when space is lost following the early loss of baby teeth either as a result of tooth decay or trauma. The Cochrane Oral Health Group undertook an extensive prioritisation exercise in 2014 to identify a core portfolio of titles that were the most clinically important ones to maintain on the Cochrane Library and this review was identified as a priority title by the orthodontic expert panel. Objectives: To test the null hypotheses that there are no differences in outcomes between 1) the age at which orthodontic treatment for crowded teeth is carried out; 2) different orthodontic interventions for correcting/preventing crowded teeth against the alternative hypothesis that there are. Search methods: We searched the following databases were searched up to July 2016: Cochrane Oral Health Group's Trials Register, Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library), MEDLINE, EMBASE. No restrictions were placed on language or date of publication when searching databases. Selection criteria: We included randomized controlled trials (RCTs) on any active interventions such as orthodontic braces (removable, fixed, functional), head-braces or extractions, against controls of no treatment, delayed treatment or another active intervention. The studies included had at least 80% of participants aged 16 years old and under. Data collection and analysis: Two reviewers independently extracted information regarding methods, participants, interventions, outcomes, harms and results, independently and in duplicate. The Cochrane risk of bias tool was used to assess the methodological quality of the studies. Main results: 19 RCTs were identified which included 1,101 participants. A meta-analysis was carried out on four papers, two that compared copper NiTi to NiTi and two that compared vibrational appliances to controls. No difference was found between either type of intervention. Additionally, subgroup analyses were carried out on thirteen other comparisons that revealed: there is low level evidence that Lower Lingual Arches and lip bumpers maintain space and prevent crowding, that the Schwarz appliance reduces crowding in the lower arch, that coaxial NiTi is better at treating crowding in the lower arch than single stranded NiTi and that self-ligating brackets are over a minute and a half quicker to untie and ligate than conventional brackets. No other statistically significant outcomes were found that were clinically significant, in any of the other comparisons. There were an insufficient number of studies to allow analysis between different age groups. Authors' conclusions: 1) There is currently insufficient evidence to allow analysis and comparisons between different age groups. 2) There are three interventions that are effective at preventing crowding in the early dentition that are the Lower Lingual Arch, lip bumper and Schwarz appliance. There is some evidence to suggest that Coaxial NiTi is better at aligning teeth and reducing crowding than single-stranded NiTi. An additional outcome of clinical interest was that self-ligating brackets are quicker to untie and ligate than conventional brackets, saving clinical time. Further high-quality evidence is needed.