The Dentist Magazine.

Impact of obesity on orthodontic tooth movement in adolescents

Published: 06/02/2017

A new clinical study undertaken at King’s College’s London Dental Institute has revealed that obesity in adolescent patients influences the supporting tissues around the tooth and the response to orthodontic treatment with fixed braces.

The study was recently published in the Journal of Dental Research and demonstrated increased levels of inflammatory biomarkers within the gingival tissues of obese patients prior to orthodontic treatment and a different response in this cohort during early tooth alignment with fixed braces when compared to normal weight patients.

In this prospective clinical cohort study, 55 adolescent patients (27 males and 28 females) with an average age of 15 years were followed from start of treatment to completion of tooth alignment with fixed braces. The participants were classified as normal weight or obese based upon their Body Mass Index (BMI).

Over the period of treatment, obese patients had a significantly increased rate of initial tooth movement and required less time to achieve tooth alignment when compared to normal weight patients. What is interesting is that a pro-inflammatory state was observed within the gingival tissues of obese patients prior to treatment, which was associated with more rapid initial tooth movement in this group. These findings demonstrate that obesity can significantly affect the oral tissues.

Obesity levels are at epidemic proportions in Western societies, representing a major healthcare challenge because of the known associations between a raised BMI and multiple chronic diseases. It is recognised that obesity is a chronic inflammatory disorder, which is caused by the presence of excess fat.

This is the first study to identify differences in orthodontic treatment response in obese patients compared to those with normal weight, and demonstrates that obesity can affect the dentition at both the biochemical and clinical level. These differences may have important implications for orthodontic treatment outcome over both the short and long term for patients with obesity.

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Richard George, director of external relations at The British Orthodontic Society, said the research is fascinating with potential for more interesting results in the future.

He said, “The prevalence of obesity is on the increase in Western societies and this study provides evidence that increased BMI can have manifestations for orthodontic patients. Significantly, the patients with obesity had a pre-existing pro-inflammatory state in their periodontal tissues and this influenced how the teeth moved with fixed braces.”

Orthodontic tooth movement is mediated by an inflammatory response within the periodontal tissues following the application of orthodontic force.

Richard commented that, “The findings that pro-inflammatory markers in obese young people are able to influence the alignment phase of orthodontic treatment immediately prompts the suggestion of how this condition might influence other aspects of treatment.”

He explained that two known complications of orthodontic treatment are root resorption and post-treatment relapse. If obesity can affect how teeth respond to fixed braces, it might also potentially influence root resorption and long term stability.

Professor Cobourne agreed and said that the research could deliver further interesting findings. The two groups of patients in the study are still in treatment and the research team at King’s are currently following them up to the completion of treatment.

He continued: “What is interesting is that we have used the same experimental model to measure and compare tooth movement in response to a variety of different clinical parameters, including self-ligating braces and the addition of vibratory forces, and we have never previously found any differences in rates of tooth movement. In this study, the presence of obesity made a significant difference.”

However, he also stated that it was important to keep these findings in context. This was a clinical study and, whilst rates of alignment were significantly increased in the obese group for all time points measured, the overall time that it took to straighten the teeth, although an average of 23 days less in the obese patients, was not statistically significant. Nonetheless, this investigation demonstrates clear differences in the biochemistry of the periodontal tissues and response to tooth movement in obese subjects when compared to those of normal weight.

Impact of Obesity on Orthodontic Tooth Movement in Adolescents, A Prospective Clinical Cohort Study by H.F. Saloom, S.N. Papageorgiou, G.H. Carpenter, M.T. Cobourne was published in the Journal of Dental Research on January 23, 2017 and can be viewed here: http://journals.sagepub.com/doi/full/10.1177/0022034516688448