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).

DATA SOURCES: 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. STUDY SELECTION: 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. DATA EXTRACTION AND SYNTHESIS: 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.