A Class II skeletal malocclusion is the most frequent skeletal problem faced in orthodontics and has a reported global prevalence of 19.6%.1–3 Often resulting in a convex facial profile, a Class II skeletal malocclusion is characterised by an anteroposterior discrepancy between the upper and lower jaws due to a retrognathic mandible, a prognathic maxilla or a combination of the two.4 If detected and treated in childhood, it is possible to improve a Class II malocclusion by taking advantage of a child’s growth spurt by growth modification or camouflage.4,5
A functional appliance is an orthodontic appliance, either fixed or removable, that is used for growth modification in late pre-adolescent and adolescent patients. Fabricated from a construction bite, a functional appliance impacts the timing and direction of skeletal growth by posturing the mandible forward to elicit forces on the surrounding muscles, their fascia and the periodontium.6 Whilst some evidence suggests that functional appliances can increase overall skeletal growth,7–9 these effects have been shown to be minimal and likely of negligible clinical importance when natural growth is considered.10–14 Ultimately, functional appliances treat Class II malocclusions by dento-alveolar and soft tissues changes that, in effect, camouflage the skeletal discrepancy.15
Functional appliances have known characteristics. Fixed functional appliances allow for significant bite advancement with limited vertical bite opening.16 However, they place a higher premium on oral hygiene and are subject to a high rate of catastrophic breakage and subsequent emergency appointments.17,18 Removable functional appliances may affect vertical bite opening and also interfere with mandibular movement which may preclude full-time use and adequate compliance.17–22 By eliminating the issue of compliance, the treatment duration of fixed appliances is often shorter.23,24 Whilst many argue that being removable is a disadvantage of a functional appliance, advocates contend that this is their greatest strength, by highlighting that they may be removed for socially sensitive occasions.25 With their relative low cost and simplicity in fabrication and repair (in most cases), removable functional appliances continue to be a popular alternative to their fixed, compliance-free alternatives.18
Perhaps the greatest controversy surrounding preadolescent functional appliance therapy, is whether it produces any significant benefit compared to the alternative, one-phase comprehensive treatment during adolescence. Multiple investigations have addressed this topic and concluded that early treatment of a Class II skeletal malocclusion during pre-adolescence is no more effective than later comprehensive orthodontic treatment during adolescence.22,24,26–33 This is explained by skeletal changes that are attained during pre-adolescent treatment tend to be, at a minimum, partially reversed by later compensatory growth.24,27 Of importance is the impact that pre-adolescent treatment has on a patient’s oral health-related quality of life. It has been shown that 16.1% of children between the ages of 10 and 14 years possessing a skeletal Class II malocclusion, experience bullying.34 It is not surprising that patients who receive pre-adolescent treatment report improved self-concepts relating to physical appearance, confidence, popularity, happiness and satisfaction.31,32,34,35 It has also been shown that resolving protrusive maxillary incisors reduces the risk of dental trauma and functional appliance therapy is a treatment option directed at this issue.32,36 Therefore, the primary indication for pre-adolescent functional appliance therapy is for psychosocial problems related to dental and facial appearance or elevated risks of incisal trauma.
As of May 2024, there were 632 registered and reported practising orthodontists in Australia, all with variability in academic training, treatment philosophy, skill, experience and laboratory resources.37 With a great variety of functional appliances available to treat a Class II skeletal malocclusion, the aim of the present study was to evaluate appliance use by orthodontists currently practising in Australia and to uncover and explain any trends seen in their prescription through the use of a nation-wide survey, thereby providing a valuable reference for intra-disciplinary quality control.
Ethical approval: The present study was a cross-sectional in design that utilised a nation-wide online survey to evaluate the use of functional appliances by orthodontists in Australia. Ethics approval was granted in accordance with the requirements of the National Statement on Ethical Conduct in Human Research (National Statement) and the policies and procedures of The University of Western Australia (2022/ET000560).
Survey development: The survey design and questionnaire were based on similar studies carried out in the United Kingdom and in Malaysia.38,39 Prior to distribution, the survey underwent in-house testing and review by five orthodontists within the University of Western Australia Department of Orthodontics, following which, minor amendments were made to ensure applicability to the Australian orthodontic community. The final survey was administered in English via Qualtrics XM®, version 04/30/2023 (Qualtrics XM®, Provo, UT, USA. https://www.qualtrics.com). The survey consisted of 22 multiple-choice and ‘rank order’ questions and was divided into four sections: demographics, appliance preference and treatment timing, provision of first phase functional appliance treatment and treatment protocols for removable functional appliance therapy (Table I). The survey was so designed that should a question be answered in a way that would make the remaining questions redundant, the survey would terminate and the participant would not need to continue. This was achieved by utilising the Qualtrics XM® ‘question behaviour’ feature. The estimated time to complete the survey was 3 minutes.
| Question Set | |
|---|---|
| Demographics |
|
| Appliance Preference and Treatment Timing |
|
| Provision of First Phase Functional Appliance Treatment |
|
| Treatment Protocols for Removable Functional Appliance Therapy |
|
Survey population and distribution: Convenience sampling was limited to orthodontists practising in Australia and registered by the Dental Board of Australia and the Australian Health Practitioner Regulation Agency. All were members of the specialist body for orthodontists in Australia, the Australian Society of Orthodontists (ASO) (n = 428 as of December 2023).40 Non-practising members, students and international ASO members were excluded from the study as they did not meet this eligibility criteria.
Permission to conduct and circulate the survey was obtained and circulated by the ASO. The survey was distributed electronically by an email link or accessed via a QR code on the ASO website and at an ASO Foundation for Research and Education conference. Prior to commencing the survey, each participant was required to electronically consent to participate. Data collection was carried out between May and November 2023. Participation was voluntary, anonymous and no incentive was provided to participate.
Data collected from completed surveys were analysed and interpreted using the Qualtrics XM® data analysis platform to create descriptive and inferential statistics. Chi square testing was conducted to identify and relate association between data sets, from which frequency tables were generated. Significance was set at P < 0.05.
A total of 166 participants consented to participate in the survey which represented a response rate of 38.8%. Of the consenting participants, 76.5% (n = 127) completed all applicable survey questions with 56% (n = 93) completing the survey in its longest version. Thirty-four participants ended their survey participation prematurely which generated a dropout rate of 20.5%. However, their responses to the answered questions were included in the study.
Most orthodontists who participated were aged between 30 and 39 years old (n = 45; 30.4%) and had been practising as specialists for zero to 9 years (n = 53; 35.8%). Seventy-eight per cent of the respondents (n = 115) obtained their orthodontic speciality qualification within Australia, with the majority graduating from the University of Melbourne (n = 32; 21.6%). The private sector was the primary place of practice (n = 132; 89.2%) and the state of Victoria (n = 42; 28.4%) recorded the highest number of practising orthodontists (Table II).
| Percentage (%) | Count (n) | |
|---|---|---|
| What is your age? | ||
| 20-29 years old | 1.4% | 2 |
| 30-39 years old | 30.4% | 45 |
| 40-49 years old | 23.7% | 35 |
| 50-59 years old | 21.6% | 32 |
| 60 years and older | 23.0% | 34 |
| In which country did you obtain your orthodontic speciality qualification? | ||
| Australia | 77.7% | 115 |
| Other | 23.3% | 33 |
| From which institution did you obtain your orthodontic speciality qualification? | ||
| University of Adelaide | 15.5% | 23 |
| University of Melbourne | 21.6% | 32 |
| University of Queensland | 18.2% | 27 |
| University of Sydney | 9.5% | 14 |
| University of Western Australia | 12.8% | 19 |
| Other | 22.3% | 33 |
| How many years have you practiced as a specialist orthodontist? | ||
| 0-9 years | 35.8% | 53 |
| 10-19 years | 21.6% | 32 |
| 20-29 years | 22.3% | 33 |
| 30-39 years | 14.2% | 21 |
| More than 40 years | 6.1% | 9 |
| In which state or territory do you primarily practice? | ||
| Australian Capital Territory | 2.0% | 3 |
| New South Wales | 14.2% | 21 |
| Northern Territory | 0.0% | 0 |
| Queensland | 27.0% | 40 |
| South Australia | 12.8% | 19 |
| Tasmania | 2.0% | 3 |
| Victoria | 28.4% | 42 |
| Western Australia | 13.5% | 20 |
| At which orthodontic service do you spend most of your clinical time? | ||
| Private clinic | 89.2% | 132 |
| Government clinic | 3.4% | 5 |
| Tertiary/university dental facility | 7.4% | 11 |
Ninety-nine per cent of the respondents (n = 139) reported prescribing functional appliances to correct a Class II malocclusion, and the Twin Block (n = 92; 32.2%) noted as the most commonly-prescribed appliance (Table III). Patient compliance and efficiency/treatment length were rated equally as the most important factors in appliance selection, and the cost of fabrication as the least important factor. Two phase, removable functional appliances followed by fixed appliance therapy (n = 66; 47.5%) was the preferred choice of Class II treatment when employing functional appliances (Table IV).
| Percentage | Count (n) | |
|---|---|---|
| Twin Block | 32.2% | 92 |
| Bionator | 2.8% | 8 |
| Activator | 0.7% | 2 |
| Headgear alone | 4.2% | 12 |
| Headgear with a concurrent functional appliance | 3.15% | 9 |
| Clear aligners with mandibular advancement features | 5.9% | 17 |
| Herbst | 18.9% | 54 |
| Forsus | 26.2% | 75 |
| Mara | 0.7% | 2 |
| Twin Force | 0.4% | 1 |
| Other | 3.9% | 11 |
| I do not use functional appliances | 1.1% | 3 |
| Percentage | Count (n) | |
|---|---|---|
| Two phase: Removable functional appliance followed by fixed appliance therapy | 47.5% | 66 |
| Two phase: Fixed functional appliance followed by fixed appliance therapy | 17.3% | 24 |
| One phase: Fixed appliance with a Class II corrector | 35.6% | 49 |
Of the 2.1% (n = 3) of orthodontists who reported that they did not prescribe a functional appliance to correct a Class II malocclusion, efficiency/treatment time was indicated as the greatest factor governing their choice.
There was no statistically significant correlation found between the number of years an orthodontist had been practising as a specialist, or their principal place of practice (private clinic, government clinic or tertiary/university dental facility) and their preferred choice of Class II treatment. However, there was a strong, statistically significant relationship between the institution from which an orthodontist obtained their speciality qualification and their preferred choice of Class II treatment (Figure 1). Of the Australian trained orthodontists, graduates from the University of Melbourne and from the University of Western Australia represented those whose greatest use was the Herbst appliance (n = 18; 33.3% and n = 8; 14.8%, respectively) and the Forsus appliance (n = 20; 26.7% and n = 16; 21.3%, respectively). Whilst graduates from the University of Queensland (n = 22; 23.9%) and from the University of Adelaide (n = 19; 20.7%) represented the greatest number of Twin Block appliance prescribers (Table V).
Impact orthodontic training institute has on preferred choice of Class II treatment when employing functional appliances.
| Q: In your clinical practice, which functional appliances do you commonly prescribe for correction of a Class II malocclusion ? (if applicable, select multiple answers) | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Total | Twin Block | Bionator | Activator | Headgear alone | Headgear with a concurrent functional appliance | Clear aligners with mandibular advancement features | Herbst | Forsus | Mara | Twin Force | Other (please specify) | 1 do not use functional appliances | ||
| Q: From which institution did you obtain your orthodontic speciality qualification? | Total Count (All) | 286.0 | 92.0 | 8.0 | 2.0 | 12.0 | 9.0 | 17.0 | 54.0 | 75.0 | 2.0 | 1.0 | 11.0 | 3.0 |
| University of Adelaide | 37.0 | 19.0 | 0.0 | 0.0 | 1.0 | 0.0 | 2.0 | 8.0 | 5.0 | 0.0 | 1.0 | 1.0 | 0.0 | |
| 12.9% | 20.7% | 0.0% | 0.0% | 8.3% | 0.0% | 11.8% | 14.8% | 6.7% | 0.0% | 100.0% | 9.1% | 0.0% | ||
| University of Melbourne | 69.0 | 8.0 | 2.0 | 0.0 | 9.0 | 4.0 | 5.0 | 18.0 | 20.0 | 0.0 | 0.0 | 3.0 | 0.0 | |
| 24.1 % | 8.7% | 25.0% | 0.0% | 75.0% | 44.4% | 29.4% | 33.3% | 26.7% | 0.0% | 0.0% | 27.3% | 0.0% | ||
| University of Queensland | 51.0 | 22.0 | 1.0 | 0.0 | 0.0 | 1.0 | 1.0 | 6.0 | 14.0 | 1.0 | 0.0 | 3.0 | 2.0 | |
| 17.8% | 23.9% | 12.5% | 0.0% | 0.0% | 11.1% | 5.9% | 11.1% | 18.7% | 50.0% | 0.0% | 27.3% | 66.7% | ||
| University of Sydney | 24.0 | 13.0 | 0.0 | 0.0 | 0.0 | 0.0 | 2.0 | 4.0 | 4.0 | 1.0 | 0.0 | 0.0 | 0.0 | |
| 8.4% | 14.1 % | 0.0% | 0.0% | 0.0% | 0.0% | 11.8% | 7.4% | 5.3% | 50.0% | 0.0% | 0.0% | 0.0% | ||
| University of Western Australia | 44.0 | 8.0 | 3.0 | 1.0 | 2.0 | 1.0 | 2.0 | 8.0 | 16.0 | 0.0 | 0.0 | 2.0 | 1.0 | |
| 15.4% | 8.7% | 37.5% | 50.0% | 16.7% | 11.1% | 11.8% | 14.8% | 21.3% | 0.0% | 0.0% | 18.2% | 33.3% | ||
| Other | 61.0 | 22.0 | 2.0 | 1.0 | 0.0 | 3.0 | 5.0 | 10.0 | 16.0 | 0.0 | 0.0 | 2.0 | 0.0 | |
| 21.3% | 23.9% | 25.0% | 50.0% | 0.0% | 33.3% | 29.4% | 18.5% | 21.3% | 0.0% | 0.0% | 18.2% | 0.0% | ||
Of the Australian states and territories, orthodontists in Queensland represented the greatest number of Twin Block appliance prescribers (n = 28; 30.4%) followed by New South Wales (n = 18; 19.6%) and South Australia (n = 17; 18.5%). Orthodontists in Victoria prescribed the greatest number of Herbst (n = 24; 44.4%) and Forsus appliances (n = 26; 34.7%), while orthodontists in Western Australian prescribed the second greatest number of Forsus appliances (n = 18; 24%) (Table VI).
| Q: In your clinical practice, which functional appliances do you commonly prescribe for correction of a Class II malocclusion ? (if applicable, select multiple answers) | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Total | Twin Block | Bionator | Activator | Headgear alone | Headgear with a concurrent functional appliance | Clear aligners with mandibular advancement features | Herbst | Forsus | Mara | Twin Force | Other (please specify) | 1 do not use functional appliances | ||
| Q: In which state or territory do you primarily practice? | Total Count (All) | 286.0 | 92.0 | 8.0 | 2.0 | 12.0 | 9.0 | 17.0 | 54.0 | 75.0 | 2.0 | 1.0 | 11.0 | 3.0 |
| Australian Capital Territory | 5.0 | 3.0 | 0.0 | 0.0 | 1.0 | 0.0 | 0.0 | 0.0 | 1.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
| 1.7% | 3.3% | 0.0% | 0.0% | 8.3% | 0.0% | 0.0% | 0.0% | 1.3% | 0.0% | 0.0% | 0.0% | 0.0% | ||
| New South Wales | 41.0 | 18.0 | 1.0 | 0.0 | 1.0 | 1.0 | 2.0 | 6.0 | 9.0 | 1.0 | 1.0 | 1.0 | 0.0 | |
| 14.3% | 19.6% | 12.5% | 0.0% | 8.3% | 11.1% | 11.8% | 11.1% | 12.0% | 50.0% | 100.0% | 9.1% | 0.0% | ||
| Northern Territory | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
| 0.0% | 0.0% | 0.0% | 0.0% | 0.0% | 0.0% | 0.0% | 0.0% | 0.0% | 0.0% | 0.0% | 0.0% | 0.0% | ||
| Queensland | 69.0 | 28.0 | 1.0 | 0.0 | 0.0 | 1.0 | 3.0 | 11.0 | 17.0 | 1.0 | 0.0 | 5.0 | 2.0 | |
| 24.1% | 30.4% | 12.5% | 0.0% | 0.0% | 11.1% | 17.6% | 20.4% | 22.7% | 50.0% | 0.0% | 45.5% | 66.7% | ||
| South Australia | 27.0 | 17.0 | 0.0 | 0.0 | 0.0 | 0.0 | 2.0 | 5.0 | 2.0 | 0.0 | 0.0 | 1.0 | 0.0 | |
| 9.4% | 18.5% | 0.0% | 0.0% | 0.0% | 0.0% | 11.8% | 9.3% | 2.7% | 0.0% | 0.0% | 9.1% | 0.0% | ||
| Tasmania | 8.0 | 2.0 | 0.0 | 0.0 | 0.0 | 0.0 | 2.0 | 1.0 | 2.0 | 0.0 | 0.0 | 1.0 | 0.0 | |
| 2.8% | 2.2% | 0.0% | 0.0% | 0.0% | 0.0% | 11.8% | 1.9% | 2.7% | 0.0% | 0.0% | 9.1% | 0.0% | ||
| Victoria | 90.0 | 15.0 | 2.0 | 1.0 | 8.0 | 6.0 | 6.0 | 24.0 | 26.0 | 0.0 | 0.0 | 2.0 | 0.0 | |
| 31.5% | 16.3% | 25.0% | 50.0% | 66.7% | 66.7% | 35.3% | 44.4% | 34.7% | 0.0% | 0.0% | 18.2% | 0.0% | ||
| Western Australia | 46.0 | 9.0 | 4.0 | 1.0 | 2.0 | 1.0 | 2.0 | 7.0 | 18.0 | 0.0 | 0.0 | 1.0 | 1.0 | |
| 16.1% | 9.8% | 50.0% | 50.0% | 16.7% | 11.1% | 11.8% | 13.0% | 24.0% | 0.0% | 0.0% | 9.1% | 33.3% | ||
Seventy-three per cent of orthodontists (n = 101) offered first phase treatment (early functional appliance treatment) during the mixed dentition for the management of a Class II malocclusion. Over the 12-month period preceding the release of this survey, 43.3% (n = 42) of orthodontists prescribed zero to 6 functional appliances. It was most common, when treating a Class II malocclusion in the mixed dentition, to complete first phase functional appliance treatment ‘only with’ or ‘majority with’ removable functional appliance therapy, 45.4% (n = 44) and 37.1% (n = 36), respectively. Less common choices included treatment ‘majority with’ or ‘only with’ fixed functional appliance therapy, 11.3% (n = 11) and 6.2% (n = 6), respectively.
Of the 26.8% (n = 37) of orthodontists who did not offer first phase treatment (early functional appliance treatment) during the mixed dentition for the treatment of a Class II malocclusion, effectiveness was identified as the primary deciding factor, followed by efficiency/treatment time, patient compliance and the cost of fabrication/purchase. Breakage and laboratory support was reported as the least important factor to not prescribe.
There was no statistically significant relation found between the institution from which an orthodontist obtained their speciality qualification, how many years they had been practising as a specialist, and their principal place of practice (private clinic, government clinic or tertiary/university dental facility). In addition, there was no statistically significant relationship between whether they offered first phase treatment (early functional appliance treatment) during the mixed dentition for the treatment of a Class II malocclusion or the number of first phase functional appliances that were prescribed during the 12 months prior to the survey.
Eighty-one per cent of orthodontists (n = 100) typically began removable functional appliance treatment when a patient was between the ages of 10 and 12 years (late mixed dentition). The most typical removable functional appliance wear regime was full time, not including mealtimes (n = 79; 64.2%) with 9 to 12 months as the most common active functional appliance phase (n = 78; 63.4%) (Table VII). There was found to be a statistically significant relationship (P < 0.05) between an orthodontist’s preferred active removable functional appliance phase length and their principal place of practice (Figure 2).
Orthodontic retention period length based on primary place of practice.
| Percentage | Count (n) | |
|---|---|---|
| What age range do you typically begin removable functional appliance therapy? | ||
| 5 years and younger (primary dentition) | 0.0% | 0 |
| 6-9 years old (early mixed dentition) | 11.4% | 14 |
| 10-12 years old (late mixed dentition) | 81.3% | 100 |
| 13 years and older (permanent dentition) | 7.3% | 9 |
| What is your typical removable functional appliance wear regime? | ||
| Full time including mealtimes | 24.4% | 30 |
| Full time not including mealtimes | 64.2% | 79 |
| Part time | 11.4% | 14 |
| How long is your active removable functional appliance phase? | ||
| 0-3 months | 0.0% | 0 |
| 4-6 months | 6.5% | 8 |
| 6-9 months | 25.2% | 31 |
| 9-12 months | 63.4% | 78 |
| Greater than 12 months | 4.9% | 6 |
| Do you encourage use of a chart or diary to measure patient compliance with removable functional appliance therapy? | ||
| Yes, routinely | 13.8% | 17 |
| Yes, occasionally | 13.8% | 17 |
| No | 72.4% | 89 |
| Following removable functional appliance therapy, do you have a period of retention when the appliance is worn less? | ||
| Yes | 75.6% | 93 |
| No | 24.4% | 30 |
| What is your routine length of post functional appliance retention? | ||
| 0-3 months | 23.4% | 22 |
| 4-6 months | 34.4% | 32 |
| 7-9 months | 11.8% | 11 |
| 10-12 months | 16.1% | 15 |
| Greater than 12 months | 14.0% | 13 |
| Do you carry out any adjustment to the removable functional appliances during the retention period? | ||
| Yes | 63.4% | 59 |
| No | 36.56% | 93 |
Twenty-eight per cent (n = 34) of orthodontists (13.8% (n = 17) routinely) encouraged the use of a chart or diary to record patient compliance. Seventy-six per cent (n = 93) of orthodontists had a period of retention following removable functional appliance therapy when the appliance was worn less. Most often, the retention period was 4 to 6 months (n = 32; 34.4%). Sixty-three per cent of orthodontists (n = 59) carried out adjustments to the removable functional appliance during this retention period (Table VII).
A Class II skeletal malocclusion is the most frequent skeletal problem in orthodontics globally. If detected at an appropriate age, this skeletal defect can be improved or camouflaged by utilising functional appliances to manipulate a child’s skeletal growth spurt.1–5
The use of functional appliances is commonplace in orthodontic practice, not only in Australia but around the world. Ninety-nine per cent of the respondents of the present survey reported prescribing a functional appliance to correct a Class II malocclusion. This is comparable to other global national figures, although geographical trends are noted. For example, 90% of Malaysian orthodontists and 75% of UK orthodontists reported the Twin Block appliance as their most popular/preferred appliance.38,39 Whereas in European, American and Scandinavian studies, the Bionator and Activator appliances were more prevalent.15,17,24,38,39 The results of the present survey indicate that orthodontists in Australia, like their UK and Malaysian colleagues, most frequently prescribe the Twin Block functional appliance. However, compared to the 75% and 90% popularity/preferred rates seen in the UK and Malaysia respectively,38,39 the prescription rate for the Twin Block appliance by orthodontists in Australia is much lower at 32.2% (n = 92). The discrepancy in these research findings is likely due to differences in questionnaire formatting. The present study allowed for the selection of multiple appliances that the respondent may regularly prescribe rather than selecting or listing only their most commonly or preferred prescribed appliance as reported in other studies.
Whilst Australian and Malaysian orthodontists listed clinical effectiveness and efficiency as the most important advantage and deciding factor for which functional appliance were prescribed, the impact and perception of cost was markedly different.38 Orthodontists in Australia cited the fabrication cost as the least important factor in their choice of functional appliance. Whereas cost-effectiveness was the second most important factor for orthodontists in Malaysia and more than half (55.6%) claimed that the fabrication cost of an appliance played a role in appliance preference.38
Along with the variation seen internationally, interstate variation is noted in Australia. The interstate variations could be explained by the teaching philosophy of each respective orthodontic training program and the likelihood of graduates from these training programs remaining in the same state to practice. For example, graduates from the University of Western Australia, orthodontists in Western Australia, graduates from the University of Melbourne and orthodontists in Victoria reported the Forsus appliance as their most commonly-prescribed functional appliance. Whereas graduates from the University of Adelaide, orthodontists in South Australia, graduates from the University of Queensland, orthodontists in Queensland, graduates from the University of Sydney and orthodontists in New South Wales all recorded the Twin Block appliance as their most commonly-prescribed functional appliance.
The ideal timing to commence functional appliance therapy is a widely debated topic within orthodontic and academic circles. Multiple studies have shown that due to factors such as compensatory growth, any skeletal improvement obtained during early treatment for a Class II skeletal malocclusion during pre-adolescence was no more effective than comprehensive orthodontic treatment conducted during later adolescence years.24,26–33,35,38 Yet, only 26.8% (n = 37) of orthodontists in Australia who responded to this survey, cited effectiveness as their primary reason and did not offer first phase treatment (early functional appliance therapy) for the management of a Class II malocclusion. Of the 73.2% (n = 101) of orthodontists in Australia who offered first phase treatment (early functional appliance treatment), 93.8% (n = 91) utilised removable functional appliances and 11.4% (n = 14) commenced therapy on patients between the ages of 6 and 9 years and 81.3% (n = 100) commenced therapy between the ages of 10 and 12 years. These prescribing patterns are in accordance with other countries such as Malaysia where 11.1% of orthodontists commence first phase treatment on patients between the ages of 6 and 9 years and 94.4% between the ages of 10 and 14 years.38 The advantages of first phase treatment is that it allows for the patient’s oral health-related quality of life along with their increased risk of incisal trauma, to be addressed. The importance of contributing to the improvement of a patient’s self-concept relating to physical appearance confidence, popularity, happiness, and satisfaction cannot be underestimated.31,32,34,35
Almost one half of orthodontists in Australia (n = 72; 43.9%) reported that Class II patients are not referred at an appropriate age for functional appliance therapy. However as oral health-related quality of life and the risk of incisal trauma is a driving force to commence first phase treatment, greater awareness and/or education of general dental practitioners in Australia regarding the preferred referral age, is needed.
A limitation of the present study includes the sample population and the subsequent risk of selection bias. The survey was distributed through the ASO and therefore, was made available exclusively to its members. Therefore, the results of the survey may not reflect the opinions and practices of all orthodontists in Australia as not all are members of the ASO. Secondary to this and for practical reasons, it was not feasible to include all conceivable market-available functional appliances (for relevant questions) in the survey, nor all available Class II malocclusion treatment options. For example, as a result of survey participant feedback, the researchers were made aware that for some orthodontists in Australia, their preferred Class II malocclusion treatment option was to manage with two phase, removable appliance therapy involving clear aligners. Subsequently, there will be an over-representation within the data of treatment choices or functional appliances available for selection, that may not truly reflect a survey participant’s clinical practice. Finally, whilst the present study adds to current knowledge regarding the use of functional appliances, the findings may not be extrapolated to represent other countries nor global healthcare systems. Therefore, further research is required with the potential for other researchers to repeat or mirror the present study’s methodology.
The current analysis of the data suggests the following concluding points regarding the use of functional appliances in Australia:
(1) It is common practice for orthodontists in Australia to utilise functional appliances in the management of a Class II malocclusion.
(2) The Twin Block appliance is the most prescribed functional appliance in Australia.
(3) There appears to be a statistically significant relationship between the institution from which an orthodontist obtained their speciality qualification and their preferred choice of Class II treatment when employing functional appliances.
(4) When utilising functional appliances, a two phase, removable functional appliance followed by fixed appliances is the preferred choice of Class II malocclusion treatment.
(5) The typical age to commence removable appliance therapy is between 10 and 12 years of age incorporating 9 to 12 months of full-time wear followed by a 4 to 6 months retention period.