Introduction
A growing number of adult patients are seeking orthodontic treatment. This research aimed to analyze the particulars of patients seeking retreatment and identify the causes of their original treatment failure.
Methods
An online questionnaire survey of adults seeking first-time orthodontic treatment (control) and retreatment (study) was conducted. Index of complexity, outcome, and need (ICON) scores were determined. Appraisal of treatment records was carried out to identify the causes of original treatment failure.
Results
No significant differences were found between retreatment adult patients and first-timers regarding reasons for seeking orthodontic treatment, malocclusion type, self-perception of malocclusion, level of self-motivation, willingness for surgery, expectations of treatment improvement and duration. The predominant reason for seeking treatment in both groups was for aesthetic concerns. Retreatment patients presented with lower ICON scores (39.4; standard error, 0.26) than the first-time patients (54.3; standard error, 0.23), P ≤0.001. The predominant reasons for original treatment failings were poor treatment, maturational changes, inadequate retention, shortcomings in diagnosis and treatment planning, and unfavorable growth. Other causes were related to transverse deficiency, secondary malocclusion (after periodontal breakdown), poor retention compliance, and temporomandibular joint degeneration.
Conclusions
Adult orthodontic retreatment and first-time seekers’ profiles are remarkably similar. Aesthetic concerns were the leading reasons patients sought treatment. ICON was not a useful proxy of patient profiles. Poor treatment was the chief reason for the failure of the original treatment. In terms of clinical significance, clinicians should be mindful of the patient profiles of retreatment seekers and vigilant about the possible causes of failings of orthodontic treatment to avoid suboptimal outcomes.
Highlights
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Adult patients seeing treatment or retreatment were compared.
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Aesthetic concerns were the leading reasons patients sought treatment.
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Poor treatment was the chief reason adults sought retreatment.
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Index of complexity, outcome, and need scores were lower in the retreatment group compared with first-time adult patients.
Adult orthodontics has seen steady growth within the last 3 decades. In the United States, reported numbers of adult orthodontic cases grew from 15.4% to 21.0% between 1981 and 2017. In 2018, a survey by the British Orthodontic Society reported members treating 5% more adult patients in private practice than in 2016.
Naturally, a proportion of adult patients seeking orthodontic treatment present with a history of previous orthodontic treatment. Many of these patients are likely to have received orthodontics as an adolescent and are commonly referred to as retreatment patients.
The majority of published research regarding adult orthodontics is focused on patients who receive orthodontics for the first time, reporting retreatment as an incidental finding. , There are few dedicated studies regarding adult orthodontic retreatment in the dental literature. These reports are often retrospective or cross-sectional investigations, with different study designs. The reasons why adults seek orthodontic treatment are multifaceted, and for an orthodontist to retreat successfully, a clear appreciation of the complexities leading to failure is needed.
This research aimed to compare patient profiles of adults seeking orthodontics for the first time and those seeking retreatment. Motivation factors, expectations, self-perception of malocclusion, orthodontic treatment need, treatment histories, retention strategies were investigated as well as identification of original treatment shortcomings/failures.
Material and methods
The study comprised both qualitative and quantitative components. A mixed-methods approach has previously been employed to study orthodontic retreatment. , Patient questionnaire responses, pre–first-time treatment, and pre-retreatment records (photographs, radiographs, study models) were analyzed together with the identification of cause(s) of the original orthodontic failure by a senior and experienced orthodontist. Ethics approval was obtained from the Human Research Ethics Committee of The University of Western Australia, RA/4/1/9311.
An adult retreatment patient is defined as a patient aged >18 years who had previously received some form of orthodontic treatment at the time of seeking retreatment. The first or initial treatment is regarded as the original treatment.
An adult first-time patient is defined as a patient aged >18 years who had never received any form of orthodontic treatment at the time of seeking treatment. These patients have often served as control groups in retreatment research.
The cohorts of adult first-time and retreatment patients were derived from the patient pool of a senior academic orthodontist in Western Australia. A patient list was generated by the practice’s management software from February 2011 to November 2017 for adults aged >18 years who presented for first-time and retreatment consultation.
Questionnaires were developed regarding previous studies, and additional questions included to address the specific aims of the study. A pilot survey was conducted on 10 retreatment patients to identify potential confusing terminology with images adopted from the textbook Contemporary Orthodontics , in addition to the Internet. The final questionnaire was designed into a digital online format using survey monkey.
Consecutive patients from the database were invited by email to participate with links to the online questionnaire and consent forms. Reminder emails were sent until the target response quota was attained.
The questionnaire consisted of multiple-choice questions, binary yes and no answers, open-ended questions, and visual analogue scales (VAS). Ren et al used the VAS in 2009 for its simplicity, sensitivity, and reproducibility. , First-time patients (control group) were asked to think back to the time of their pretreatment consultation, whereas retreatment patients (study group) cast their minds back to pre-original-treatment and pre-retreatment consultations. Asking patients to think back to a former time has been used for investigating orthodontic retreatment.
All questionnaires collected data regarding sociodemographics, motivation factors, motivation levels, treatment preferences, self-perception of malocclusion, and treatment expectations. The retreatment questionnaire included additional questions regarding the original treatment history, retention appliances, retention protocols, and self-reported reasons why they thought the original treatment had failed.
The socioeconomic indexes for area (SEIFA) constructed by the Bureau of Statistics 2016 were used to assess socioeconomic status. The index of relative socioeconomic disadvantage was chosen.
Pretreatment for first-timers (control group) and pre-retreatment records (study group) included extraoral and intraoral photographs, digital study models, lateral cephalometric, and panoramic radiographs. Pre-original treatment records of the retreatment group were not available.
Pretreatment clinical photographs were used to classify malocclusion for both the study and control groups. A single most salient defining feature of each malocclusion was recorded.
First-time and retreatment digital study models were scored using the index of complexity, outcome, and need score (ICON). A single investigator (L.C.) performed the ICON scores for all samples after calibration by an experienced external calibrator. , When digital model records were unavailable, clinical photographs were used to complete scores.
Anticipated reasons for original treatment failure were based on a literature review and divided into 3 major groups: patient factors, original orthodontist error, and biologic reasons. A single orthodontist with >30 years of experience, which patients consulted for retreatment, analyzed the clinical records to identify the problems associated with the original treatment.
Statistical analysis
The sample size was estimated a priori to be 97 patients for each group and rounded to 100. Sample size calculation and statistical analyses were performed with R 3.5.0 (R Foundation for Statistical Computing, Vienna, Austria). A similar study on orthodontic retreatment surveyed 88 subjects.
Results
A total of 460 patients were invited to participate in the study (retreatment: n = 200; first-time: n = 262). The response rate for the retreatment (study) group was about 50% (n = 99), and 40% (n = 100) for the first-time (control) group. Incomplete responses were excluded ( Table I ).
| Characteristics | Original | Retreatment | Control |
|---|---|---|---|
| Patient no. | – | 99 | 100 |
| Response rate, % | – | 50 | 40 |
| Gender, n | |||
| Male | – | 20 | 32 |
| Female | – | 79 | 68 |
| Age groups, n | |||
| <18 | 80 | – | – |
| 18-28 | 6 | 27 | 16 |
| 29-39 | 6 | 28 | 29 |
| 40-50 | 6 | 30 | 27 |
| >59 | 1 | 14 | 28 |
| Mean age, years | 16.9 | 38.2 | 41.9 |
| Marital status | |||
| Single | 89 | 44 | 27 |
| Married | 8 | 52 | 64 |
| Widowed | 0 | 0 | 2 |
| Not specified | 2 | 3 | 7 |
| SEIFA in deciles, n | |||
| 10th (highest SES) | – | 40 | 26 |
| Ninth | – | 20 | 23 |
| Eighth | – | 9 | 16 |
| Seventh | – | 9 | 10 |
| Sixth | – | 8 | 8 |
| Fifth | – | 6 | 8 |
| Fourth | – | 5 | 3 |
| Third | – | 1 | 2 |
| Second | – | 1 | 3 |
| First (lowest SES) | – | 0 | 0 |
| Missing | – | 0 | 1 |
| Mean | – | 8.26 | 7.85 |
| Standard deviation | – | 2.04 | 2.13 |
The retreatment group (n = 99) consisted of 20 males and 79 females. The control group (n = 100) had 32 males and 68 females. There were significantly more females than males in both groups ( Table I ).
Overall, the groups were statistically well matched for age. Most of the retreatment patients (80 of 99) received their original treatment when aged <18 years. The retreatment group age distribution was fairly even except there were fewer aged >50 years when compared with the control. There was no age difference between the retreatment group (mean, 38.2 years) and the control group (mean, 41.9 years, P = 0.0535). The mean age was 16.9 years at original treatment and 38.2 years at retreatment; this indicated an average of 21.3 years had elapsed before patients sought retreatment ( Table I ).
There were no significant differences in gender and age between the groups ( P = 0.08) except for the first-time treatment males were slightly older (mean, 41.3 years) than retreatment counterparts (mean, 34.5 years; P = 0.0259) ( Table I ).
There were higher numbers of married patients in both groups. A binomial test showed even numbers of married to single females (1:1) in the retreatment group ( P = 0.475). In the control group, however, married to unmarried women were more than 2:1 ( P = 0.0001) ( Table I ).
For the retreatment and control groups, >75.0% were placed in the seventh or higher SEIFA decile. A greater proportion of the retreatment group (40.4%) compared with the controls (26.0%) were in the 10th (highest) SEIFA decile. Few patients in both groups (19.0%) were in the fourth-sixth deciles. In the second and third deciles, there were fewer still, with retreatment group (2.0%) and control (5.0%). No patients were in the lowest SEIFA decile. A t test showed no difference in mean income deciles between groups ( P = 0.1643) ( Table I ).
Most patients received their original treatment in Australia (73 of 99) followed by the United Kingdom (15 of 99), with 90 patients fully completing their treatments. Most patients (89 of 99) were treated by orthodontists with 10 of 99 by general dentists. The most common original treatments were fixed appliances with extractions, followed by fixed appliances without extractions. Metal brackets were used in 97% of patients.
Sixty of 99 retreatment patients reported that they were issued with a retainer, 29 had no retainer, whereas another 10 were unsure if they had. Among those issued with retainers, 38 reported to be compliant , 20 were non-compliant, and 2 were unsure . Patients were only deemed compliant if they reported having worn retainers for >12 months. Those reported to have worn retainers for <12 months and those that were unsure were deemed non-complaint ( Table II ). Removable Hawley retainers were the most common maxillary retainer; next was vacuum-formed retainers for both the maxillary and mandibular arches; followed by mandibular Hawleys; and finally, fixed retention. Of the 60 patients issued with retainers, only 13 (21.7%) were fitted with fixed retainers ( Table III ).
| Original patients issued with retainers | n | Reported compliance | n |
|---|---|---|---|
| Yes | 60 | Compliant | 38 |
| Non-compliant | 20 | ||
| Unsure | 2 | ||
| No | 29 | – | – |
| Unsure | 10 | – | – |
| Original patients fitted with fixed retainers | Patient no. |
|---|---|
| No | 46 |
| Yes | 13 |
| Unsure | 1 |
| Total | 60 |
Respondents were allowed to report more than one source of motivation. Most adult patients were self-motivated (retreatment, 71.1%; control, 68.7%). The second most common source of motivation was from general dentists (retreatment, 11.6%; control, 22.6%). For the original treatment group, the majority (60.9%) were motivated by their parents when they were teenagers ( Table IV ).
| Motivation source | Original | Retreatment | Control |
|---|---|---|---|
| Self | 19.1 | 71.1 | 68.7 |
| Dentist | 19.1 | 11.6 | 22.6 |
| Orthodontist | 0 | 6.61 | 0.87 |
| Spouse | 0.87 | 3.31 | 1.74 |
| Others | 0 | 4.13 | 3.48 |
| Parents | 60.9 | 2.48 | 1.74 |
| Relative | 0 | 0.83 | 0 |
| Friend | 0 | 0 | 0.87 |
Again, respondents were allowed to give multiple answers. Therefore, the data was reported as a frequency (counts) as opposed to a number of patients. The main reasons subjects sought orthodontic treatment for all groups were for aesthetic concerns (eg, crooked or crowded teeth , to improve smile, and to improve facial appearance ). Retreatment seekers were frequently motivated because of the relapse of original treatment , and original treatment did not work . Few reported being motivated because of jaw positions , wanting to improve chewing ability , airway issues , or problems with the jaw joints ( Table V ).
| Reason | Frequency of response, n | ||
|---|---|---|---|
| Control | Original | Retreatment | |
| Crooked or crowded teeth | 48 | 65 | 42 |
| To improve smile | 43 | 11 | 37 |
| Relapse of original treatment | NA | NA | 34 |
| Original treatment did not work | NA | NA | 20 |
| To improve facial appearance | 27 | 12 | 18 |
| Spaces between teeth | 19 | 9 | 13 |
| Airway problems | 6 | 0 | 12 |
| Problems with jaw joints | 4 | 3 | 12 |
| Demands of facial aesthetics increased | NA | NA | 11 |
| Protruded maxillary jaw and/or retruded mandibular jaw | 11 | 12 | 11 |
| Protruded maxillary teeth and/or retruded mandibular teeth | 9 | 22 | 11 |
| To improve chewing ability | 15 | 5 | 9 |
| Missing teeth | 11 | 7 | 5 |
| Retruded maxillary jaw and/or protruded mandibular jaw | 8 | 2 | 3 |
| To improve speech | 4 | 1 | 3 |
| Retruded maxillary teeth and/or protruded mandibular teeth | 5 | 3 | 2 |
| Excessive gum shown when smiling | 2 | 1 | 2 |
| Impacted teeth | 4 | 4 | 2 |
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