Introduction
With more dentists performing orthodontics, identifying and managing patients at risk or affected by orthodontically-induced external root resorption (OIERR) is paramount.
Methods
This study, conducted according to STROBE (STrengthening the Reporting of OBservational studies in Epidemiology), studied Australian orthodontists. Orthodontists were asked to complete a clinical questionnaire evaluating their diagnostic and management approaches to OIERR.
Results
Orthodontists most commonly use a history of previous root resorption and the use of an orthopantomogram to screen and monitor patients. An orthopantomogram is used either 6 months for those identified as at risk of OIERR or 10-12 months for those who are not. Once detected, most orthodontists will record OIERR in terms of severity. If severe root resorption was detected, orthodontists would compromise on the treatment outcome and promptly complete treatment; if extraction sites remain closed, most orthodontists will interrupt treatment for 3-6 months. After treatment, orthodontists’ retention protocol is unchanged regardless of OIERR experience. Treatment planning for patients with generalized OIERR before treatment ( P = 0.002) was the only decision shown to be associated with years of clinical experience ( P >0.05).
Conclusions
It is shown that no 1 method for managing OIERR exists, with most orthodontists arguing patient specificity to treatment modality. The various selected clinical approaches accurately reflect the current state of scientific literature on the topic.
Highlights
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No one method exists for managing orthodontically induced external root resorption.
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Root resorption may be an unavoidable consequence of orthodontic treatment.
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Selected clinical approaches reflect the state of the literature on OIERR.
Orthodontic appliances work by placing force on a tooth in a prescribed direction. This force results in either tension or compression of the periodontal ligament, resulting in trauma followed by the release of inflammatory mediators. Although the inflammatory response leads to tooth movement, it can also cause orthodontically-induced external root resorption (OIERR). Forces applied to the periodontal ligament can lead to load-induced sterile necrosis. , resulting in irreversible resorption of superficial root cementum and, in more severe patients, the underlying dentin.
The incidence of OIIRR may affect as many as 80% of patients undergoing orthodontic treatment, and although OIERR can affect any tooth, it is most prevalent in the maxillary incisors.
Although it has been shown that the majority of patients undergoing orthodontics are at risk of root resorption, it is argued that it is the orthodontists’ role to manage and mitigate the severity. , , , Failure to do so can result in negligence, with litigation potentially brought on the clinician. , As currently no single clinical approach to OIERR has been identified, the clinician must rely on their experience and perceptions, combined with patient evaluation, to provide suitable care. Because of the deleterious consequences of OIERR for patient and clinician alike, it is therefore pertinent that orthodontists employ methods which limit the amount of irreversible OIERR patients experience during orthodontics. As OIERR is shown to be the result of an interrelationship between mechanical and individual factors, , it remains pertinent that the clinician adopts treatment methods that mitigate the risk and severity. In the absence of clear clinical guidelines, in some jurisdictions, as long as the clinician’s actions are determined to be suitable by a responsible body of medical opinion, the practitioner is incapable of negligence.
The current evidence regarding OIERR involves taking the results of short-term studies and applying them to a phenomenon experienced during long-term treatment. This limits the strength of evidence-based practice when aiming to mitigate the incidence and/or severity of root resorption during active orthodontic therapy. Therefore, clinician expertise must then be explored to strengthen clinical decision-making and thus treatment.
This study aimed to therefore investigate the clinical approach that orthodontists’ currently use to identify and manage patients at risk or affected by OIERR. This method of clinical practice may then aid the clinician in the reduction of irreversible tooth structure loss and improve patient outcomes.
Material and methods
This cross-sectional study is described according to the STROBE (STrengthening the Reporting of OBservational studies in Epidemiology) guidelines for the presentation of cross-sectional studies. Approval was attained from the Human Research Ethics Committee of James Cook University, Queensland, Australia (H7272). The study was conducted in Australia by participating specialist orthodontists. Inclusion criteria were orthodontists whose contact information was available through keyword searches on a Web-based search engine (Google, Menlo Park, Calif) using the term orthodontist and limited to Australian states and territories, whereas orthodontists practicing primarily in university settings were excluded. The formulated list was checked against the online database of registered specialist orthodontists held by the Australian Health Practitioner Agency. Any orthodontist who did not appear in the database was excluded from the study.
The questionnaire was adapted from a previously published study. Electronic questionnaires were prepared and, before dissemination, validated by an expert panel of 5 senior academic orthodontists from Australia’s 5 accredited university postgraduate orthodontic programs. The test-retest reliability of the questionnaire was determined using Cohen’s kappa. This was performed using 10 registered specialist orthodontists 1 week apart. After attainment of validity and reliability, the survey was pilot-tested by 5 orthodontists. Questionnaires were completed using an online platform (SurveyMonkey, San Mateo, Calif) and were automatically recorded and deidentified. The surveys also captured the orthodontist’s gender, university of qualification, and years of practicing experience ( Fig 1 ) . Orthodontists were recruited from April 2018 to June 2018. After the initial mail-out, 2 reminder e-mails were sent, prompting orthodontists to complete the questionnaire. The trial concluded 3 weeks after the final reminder was sent.
Statistical analysis
As 608 orthodontists are currently registered in Australia, 149 completed questionnaires would be sufficient to provide an accuracy of at least ±7% for any questionnaire item, with 95% confidence. The primary analysis was descriptive, showing counts, and percentages. Percentages were reported as proportions of the total for each survey question. A simple thematic analysis was undertaken for open-ended items. The association between questionnaire items was assessed using chi-square and Fisher exact tests. A cutoff of P ≤0.05 was considered to be statistically significant. SPSS Statistics software (version 25; IBM, Armonk, NY) was used to analyze the data.
Results
The kappa value for the test-retest of the questionnaire was analyzed to determine reliability. The lowest value of kappa for any questionnaire item was 0.7, indicating good reliability of the questions. Of the 480 orthodontists contacted, 202 agreed to participate in the study (42.1%), of which 161 fully completed the questionnaire giving an analyzed response rate of 33.5%. Table I shows the demographic information of the sample population; respondents were mostly male, in private practice, and with at least 10 years of experience.
| n | % | |
|---|---|---|
| Gender | ||
| Male | 114 | 70.8 |
| Female | 47 | 29.2 |
| Total | 161 | 100.0 |
| Years experience, y | ||
| <1-5 | 27 | 16.8 |
| 6-10 | 23 | 14.3 |
| 11-20 | 39 | 24.2 |
| >20 | 72 | 44.7 |
| Total | 161 | 100.0 |
| University of postgraduate specialist education | ||
| Queensland | 25 | 15.5 |
| Sydney | 31 | 19.3 |
| Melbourne | 35 | 21.7 |
| Adelaide | 18 | 11.2 |
| Western Australia | 7 | 4.3 |
| Otago | 11 | 6.8 |
| Other | 34 | 21.2 |
| Total | 161 | 100.0 |
| Primary place of practice | ||
| Private practice | 147 | 91.3 |
| Public/hospital | 11 | 6.8 |
| Other | 3 | 1.9 |
| Total | 161 | 100.0 |
The orthopantomogram (OPG) was the most commonly used method of pretreatment screening for OIERR (97.5%). Before the commencement of orthodontic treatment, previous root resorption (94.4%), history of dental trauma (85.1%), and root shape and position (80.7%) were considered important risk factors for OIERR. In patients identified as high risk of OIERR, more orthodontists would alter their treatment plan to offer nonextraction and opt to camouflage discrepancies when possible (36.0%), compared with treating the patient as a routine case (11.2%), Table II .
| Years experience, y | Total | P value | ||||
|---|---|---|---|---|---|---|
| <1-5 | 6-10 | 11-20 | >20 | |||
| Patient factors | ||||||
| History of trauma to dentition | 24 (88.9) | 17 (73.9) | 35 (89.7) | 61 (84.7) | 137 (85.1) | 0.355 |
| Previous root resorption | 26 (96.3) | 20 (87.0) | 38 (97.4) | 68 (94.4) | 152 (94.4) | 0.350 |
| Family history of resorption | 20 (74.1) | 16 (69.6) | 22 (56.4) | 57 (79.2) | 115 (74.1) | 0.088 |
| Transplanted tooth | 21 (77.8) | 15 (65.2) | 22 (56.4) | 54 (75.0) | 112 (70.1) | 0.154 |
| Medical condition | 6 (22.2) | 1 (4.3) | 12 (30.8) | 12 (30.8) | 27 (16.8) | 0.017 |
| Patient ethnicity | 5 (18.5) | 1 (4.3) | 4 (10.3) | 3 (3.9) | 13 (8.1) | 0.109 |
| Root shape and position | 22 (81.5) | 19 (82.6) | 33 (84.6) | 56 (77.8) | 130 (80.7) | 0.839 |
| Clinical factors | ||||||
| Previous dental history | 19 (70.4) | 13 (56.5) | 29 (74.4) | 45 (62.5) | 106 (65.8) | 0.432 |
| Clinical examination | 8 (29.6) | 2 (8.7) | 12 (30.8) | 21 (29.2) | 43 (26.7) | 0.186 |
| OPG | 27 (100.0) | 21 (91.3) | 38 (97.4) | 71 (98.6) | 157 (97.5) | 0.194 |
| Periapical radiograph | 9 (33.3) | 9 (39.1) | 18 (46.2) | 34 (47.2) | 70 (43.5) | 0.608 |
| Cone-beam computed tomography | 7 (25.9) | 9 (39.1) | 9 (23.1) | 27 (37.5) | 52 (32.3) | 0.340 |
| Treatment planning a patient presenting with generalized root resorption and requiring extractions | ||||||
| Do not recommend treatment, advise against treatment indefinitely | 1 (3.7) | 5 (21.7) | 9 (23.1) | 12 (16.7) | 27 (16.8) | 0.147 |
| Do not recommend treatment for now, plan for recall | 8 (29.6) | 5 (21.7) | 4 (10.3) | 15 (20.8) | 32 (19.9) | 0.243 |
| Offer nonextraction and camouflage | 16 (59.3) | 8 (34.8) | 19 (48.7) | 15 (20.8) | 58 (36.0) | 0.001 |
| Offer extraction but allow for migration | 6 (22.2) | 4 (17.4) | 7 (17.9) | 13 (18.1) | 30 (18.6) | 0.972 |
| Extract and continue as routine case | 2 (7.4) | 2 (8.7) | 6 (15.4) | 8 (11.1) | 18 (11.2) | 0.806 |
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