Adherence among Orthodontic Patients

Student thesis: Doctoral ThesisDoctor of Philosophy


Objectives: A patient’s adherence is an important factor for successful orthodontic treatment. This adherence can take the form of maintaining good oral hygiene, appliance maintenance, observing dietary recommendations, and appointment keeping. This thesis consisted of three studies. A systematic review was conducted to investigate the effectiveness of interventions to enhance adherence among orthodontic patients aged 12 to 18. Specific adherence outcomes included: recall of information given by the orthodontic team; attendance at orthodontic appointments; self-reported oral hygiene behaviour; and clinical indices of oral hygiene. A survey was undertaken to explore predictors of adherence amongst patients 12–18 years of age receiving orthodontic treatment with fixed appliances at the initial follow-up appointment 6 weeks post bracket placement. Finally, a randomised controlled trial compared three methods designed to enhance adherence to oral hygiene instructions in orthodontic patients aged 12–18 years: mind map, if-then plan, and leaflet.Materials and Methods: Systematic review: Electronic searches of Medline via OVID (1966– March 2012), EMBASE, and the Cochrane central register of control trials from its inception to March 2012, as well as a hand search were undertaken to identify relevant studies.The longitudinal study: Measured adherence to orthodontic treatment in terms of self-reported oral hygiene-related behaviour, oral hygiene maintenance, knowledge of oral health-related behaviour, appliance breakages, and appointment attendance among 200 individuals undergoing maxillary and mandibular fixed orthodontic appliances with an age range of 12 to 18 years. Oral health-related behaviour and clinical indicators of oral healthwere assessed at bond-up appointment (T1) and at 6 weeks follow up appointment (T2) to determine their relationship to adherence.Randomised controlled trial: Orthodontic patients from Guy’s and St Thomas’ NHS Trust were drawn as potential participants; patients were randomly allocated to one of the three interventions used. Eligibility criteria: patients aged 12–18 years undergoing maxillary and mandibular fixed orthodontic treatment. Individuals with systemic disease, craniofacial development disorders including cleft lip and palate, individuals with previous history of orthodontic treatment, patients attending the specialist hypodontia clinic and individuals who declined to participate were excluded. Outcomes: Primary outcomes: plaque levels. Secondary outcomes: bleeding on probing, patient’s knowledge about adherence in orthodontic treatment, and self-reported behaviours. Randomisation: patients were randomly allocated to one of three conditions. The three groups were: mind mapping, if-then planning group, and patient information tools (leaflet). Allocation was concealed using sealed envelopes. Blinding: the participant and their parents as well as the researcher undertaking the intervention and assessing the outcomes were not blinded. The statistician undertaking the statistical analysis was blinded. Participants were assessed at four time points: at the fitting of the fixed appliance (T1); at initial follow-up 6 weeks later, at which time after the assessment of their oral hygiene and completion of the questionnaire (T2), they were randomly allocated to the three groups of intervention; 6 weeks after the intervention (T3); and 18 weeks after the intervention (T4).Results: Systematic Review: A total of 381 articles were identified through the electronic searches. Initial screening of the abstracts and titles by all review authors identified 7 articles that met the inclusion criteria for this review. The full articles were then retrieved.Four randomised controlled trials were found; all used different methods of intervention, including: a system of rewards or awards; the Hawthorne effect; written information; and demonstration of the microbiology of plaque.The longitudinal study: Significant changes in lingual plaque (P= 0.026), bleeding on probing (P= 0.006), and knowledge (P<0.001) were found between bond-up and at initial follow-up. There were no relationships between age and gender of the patients and adherence. Clinical status at bond-up was the only significant predictor of clinical status at initial follow-up.Randomised Controlled Trial: Total sample of 90 participants were randomised in a 1:1:1 ratio. No statistical differences were found in adherence among the three methods used.Conclusion: The literature advocates the use of several methods to improve compliance/adherence among orthodontic patients. While there is insufficient evidence to allow clinicians to choose a single method, the results demonstrate the value of spending time with patients to illustrate the importance of adherence. Future studies should develop multiple methods of assessing patient adherence including self-report, behavioural observation and recording, as well as change in clinical indices, with different types of interventions to be included and tested for effectiveness. The survey demonstrated that the oral hygiene of patients worsens following the start of orthodontic treatment. Age, gender, and knowledge are not good predictors of adherence. However, initial clinical status predicts subsequent adherence. The randomised controlled trial revealed no differences in adherence among the three methods used.
Date of Award2016
Original languageEnglish
Awarding Institution
  • King's College London
SupervisorTim Newton (Supervisor) & Fraser McDonald (Supervisor)

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