title: The impact of malocclusion and its treatment on the oral health related quality of life of adults, assessed using the Oral Health Impact Profile (OHIP-14).
abstract: METHODS
  PubMed, Medline and Embase via OVID were searched up to November 2013. This was supplemented by a hand search of the reference lists of all relevant publications and recently published review articles. The search was restricted to the English language.
  
  
  METHODS
  Two review authors independently searched and selected the studies. Interventional or observational studies of individuals aged 15 years and above with either a malocclusion, or those who had undergone treatment for a malocclusion, were included. Studies must have included a control group without a malocclusion (for assessment of malocclusion impact), or a control group requiring treatment for correction of malocclusion (to assess the impact of treating malocclusion). Oral health related quality of life (OHRQoL) had to be measured using OHIP-14.
  
  
  METHODS
  Two review authors independently carried out data abstraction and methodological quality assessment. Studies were divided into three groups based on the type of comparison groups; with and without malocclusion (independent design), the same group of individuals before and after treatment (pre-post design), and an orthodontically treated group with a group requiring treatment (treated-untreated groups design). For each group, data were pooled if the same type and details of OHIP-14 scores were reported. A Q test, I(2) test and random-effects model were used. Begg and Egger tests and funnel plots were used to measure bias, including publication bias.
  
  
  RESULTS
  Twenty-five studies were included; eleven studies had an independent design, ten studies were classed as pre-post studies, and four studies were categorised as demonstrating a treated-untreated groups design. Data from four of the independently designed studies, which included a total of 892 patients, were pooled and a meta-analysis conducted. The data from three of the pre-post designed studies, with a total of 110 patients, were also pooled in a separate meta-analysis. The standardised mean difference (SMD) in OHIP-14 total score in the independently designed studies was 0.84 (95% CI: 0.25 to 1.43) and in the pre-post design group was 1.29 (95% CI: 0.67 to 1.92). The studies in both meta-analyses demonstrated statistically significant levels of heterogeneity. There was also evidence of publication bias in the meta-analysis conducted using the independently designed studies.
  
  
  CONCLUSIONS
  There are currently no high quality studies in the form of longitudinal or randomised controlled trials to assess the impact of malocclusion and its associated treatment on OHIP-14 scores respectively. Results from existing studies, which are predominantly cross-sectional, suggest that OHIP-14 scores are significantly lower in individuals without a malocclusion, indicating higher levels of OHRQoL. Similarly, longitudinal studies have shown that OHIP-14 scores are significantly lower after patients have received treatment for their malocclusion. The small number of trials, and their associated methodological concerns, limits the validity and reliability of the meta-analyses conducted, and the results obtained must be subjected to further scrutiny and confirmation.
authors.affiliation: Academic Unit of Oral Health and Development, University of Sheffield.
authors.forename: Hanieh
authors.initials: H
authors.lastname: Javidi
authors.affiliation: Academic Unit of Oral Health and Development, University of Sheffield.
authors.forename: Philip
authors.initials: P
authors.lastname: Benson
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D006801:Humans; D008310:Malocclusion; D009909:Oral Health; D011788:Quality of Life; D015203:Reproducibility of Results