‘Mind the gap!’ … Gaps in the mind. A trial looking at quality of life.

They carried out a two-group randomized controlled trial with a 1:1 allocation (44 participants overall with 47 missing lateral incisors) over a 12-month observation period as follows:

Participants: 

• Aged 17 to 49 years
• With one or two missing maxillary lateral incisors
• Class I, II or III
• Spacing between central incisor and canine

Intervention Group:

The treated group received fixed appliances to space close for the missing lateral incisors with recontouring of the canines to aid substitution.

Control Group:

The control group did not receive orthodontic treatment during the first 12 months of the study.

Primary outcome(s):

The primary outcomes were Oral Health-related Quality of Life (OHRQoL) and self-esteem.

They used the Oral Health Impact Profile (OHIP-14) questionnaire to assess OHRQoL. This considers oral symptoms, functional limitations, emotional well-being, social well-being, and overall perceptions of general well-being and oral health.

They also used a further validated questionnaire (Rosenberg’s Self-Esteem Scale)  to assess self-esteem. The participants completed the questionnaires at baseline in both groups and again after 12 months in the control group. I had a constructive e-mail exchange with the author,  and they made it clear that they did the last assessment in the intervention group after they had removed the appliances.

What did they find?

The authors undertook several within-group comparisons. I am not sure how necessary these are. I will, therefore try to focus on the between-groups comparisons. Overall, the authors observed an improvement in both self-esteem and OHRQoL in the treatment group. In an adjusted statistical model accounting for demographics, clinical factors and baseline scores, the treated group continued to have better outcomes than the control group. The authors also inferred that participants with higher self-esteem and OHRQoL and lower education level benefitted most from the treatment.

What did I think?

I think that this was an interesting study. I like the fact that the outcomes were simple and of relevance. In particular, the authors limited their analysis to just two outcomes. This step ensured that the study is focused and there is less risk of false-positive, spurious conclusions. In terms of the outcome measures that they used, they used validated questionnaires. However, these do also involve very general measures of quality of life and self-esteem. I do wonder how potent orthodontics may or may not be in affecting this (particularly among adults). There has also been quite a bit of progress in developing more specific, orthodontically-relevant measures in recent years, albeit tailored for adolescent groups.

I also like the subject matter. The decision as to whether to space open or close with missing lateral incisors is a conundrum that we face regularly. I do tend to gravitate towards space closure whenever I can. This treatment reduces the onus on long-term restorative maintenance and may simplify retention to an extent. Nevertheless, there is maintenance involved in preserving the result, and retention is pivotal to long-term success. I wonder whether a more prolonged follow-up might be useful in assessing the long-term benefit of treatment on these patient-related parameters. Also, completion of questionnaires at or soon after removing the appliances risks over-estimating the beneficial effect of treatment in light of the ‘euphoria’ sometimes associated with debonding.

The participants and malocclusion

Furthermore, the study focused on relatively mature participants (17-49 years). Therefore, the evaluation of a younger patient cohort might be more interesting; nevertheless, the study provides us with new and interesting information. I mentioned that they made within-group comparisons. I think that these add little. The finding of a deterioration in self-esteem and quality of life within the untreated control group is surprising. I am struggling to see how this would be anything but stable in an adult population.

A final caveat is that the authors failed to highlight the magnitude of visible space and the presence of primary teeth in the aesthetic zone. They did allude to the presence of space mesial to the permanent canine; however, spacing’s size and location are likely to be pivotal to any patient impacts.

What can we conclude?

In a post-adolescent cohort, orthodontic space closure in the presence of missing maxillary lateral incisors may help to improve self-esteem and oral health-related quality of life in the short term.