Functional needs of subjects with dentofacial deformities: A study using the index of orthognathic functional treatment need (IOFTN)

Summary

Objectives

To assess the functional needs of orthognathic patients treated in Isfahan University of Medical Sciences affiliated hospitals using the index of orthognathic functional treatment need (IOFTN).

Materials and methods

A retrospective study was conducted using 2011–2015 records of 103 patients [58 female, 45 males, 16–45 years, mean (SD) age = 23.47 (6.44) years] who had orthognathic surgery. Malocclusion type (incisor classification), sagittal skeletal pattern (ANB angle), IOFTN score, and Dental Health Component of the IOTN [IOTN (DHC)] were recorded.

Result

Overall, 92.2% and 82.5% of subjects scored 4 or 5 for IOFTN and IOTN (DHC), respectively, and no gender differences detected for both indices (P > 0.05). Gender differences detected for malocclusions/skeletal patterns (P < 0.05). Class III malocclusions (45.6%) and Class II skeletal patterns (51.5%) were the most prevalent type. Subjects with Class I, Class II, and Class III sagittal skeletal bases formed 4.8%, 51.5%, and 43.7% of the sample, respectively. IOFTN score of 5.3 (reverse OJ ≥ 3 mm, 27.2%) was the most prevalent, followed by 4.2(19.4%), 4.3(13.6%), 4.10 (12.6%), and 5.2 (8.7%). Subjects with Class III sagittal skeletal patterns or malocclusions had higher percentages of grade 5 IOFTN scores (62.2% and 59.6%), compared to Class II sagittal skeletal patterns or malocclusions (18.9% and 21.2%) and the distribution of functional needs between malocclusions or sagittal skeletal patterns were different (p < 0.01).

Conclusion

IOFTN identified 92.2% of orthognathic surgery patients as having great and very great functional needs and appeared to be reliable tool to identify patients in need of orthognathic surgery. Higher percentages of Class III subjects scored grade 5 of IOFTN, indicating higher functional need for orthognathic surgery in this group.

Introduction

Orthognathic surgery often involves surgical procedures on the mandible, maxillae, or both, as well as their dentoalveolar segments to reposition the jaws into their normalised or functional relationship in subjects with dentofacial deformities.

Reports indicates that approximately 5% of the UK or USA population present with dentofacial deformities that are not amenable to orthodontic treatment only, requiring orthognathic surgery as a part of their definitive treatment.¹ Although preparation of orthognathic patients has been recently modified with introduction of the surgery-first approach,² conventional approach often includes a course of orthodontic treatment before and after orthognathic surgery.

Approximately, 2600–2900 patients undergo orthognathic surgery annually in England and Wales and the average costs of these treatments in 2012 ranged from £4000 to £8000 per case.³ In the UK, orthognathic surgeries are funded by NHS England for patients with malocclusions and severe dentofacial deformities. The funding should be allocated to patients with the Index of Orthodontic Treatment Need (IOTN)⁴ score of 4 or 5 and functional symptoms that have an important impact on patients' quality of life. With the current drive to reduce costs within the NHS, and in particular, to redirect resources from low priority treatments, to those considered to be high priority and their use is supported by evidence, having an index to objectively identify those treatment/patients seems necessary.

The index of orthognathic functional treatment needs (IOFTN) has been recently developed by Ireland et al. in the UK, aiming at prioritizing severe malocclusions not amenable to orthodontic treatment alone and need orthognathic surgery.⁵ IOFTN has 5 categories, from a Very Great Need (grade 5) through to No Need for treatment (grade 1) (Table 1). Ideally, the funding should be used for patients with grades 4 and 5 of the IOFTN. The index has similarities with the IOTN, however, it has modifications to reflect the functional aspects of treatment need for orthognathic patients, which are missing in the IOTN, such as patients with sleep apnoea not amenable to Mandibular Advancement Device (MAD) or Continuous Positive Airway Pressure (CPAP), complete buccal scissors bite with functional implications (both categorised as graded 5 IOFTN) as well as maxillary labial gingival exposure greater than 3 mm (grade 4 IOFTN). The index does not support the provision of orthognathic treatment for speech or TMJ disorders.

IOFTN has been used in the UK,5, 6, 7 but its external validity has not been tested outside the UK. It would be interesting to see if IOFTN identifies subjects who had orthognathic treatment outside the UK as having great or very great functional need for surgery. Therefore, the primary objective of the present study was to assess, retrospectively, the functional needs of orthognathic cases treated in a university setting in Isfahan, Iran, using the IOFTN; and to compare the finding to reports from the UK. The secondary aim was to compare the functional needs (using the IOFTN) of patients with different malocclusions and sagittal skeletal patterns.