Linking orthodontic treatment and sleep apnea among adult Indian patients

The differences in the effects of orthodontic treatment on airway and craniocervical posture in patients with OSA (obstructive sleep apnea) having skeletal class II high-angle malocclusion is of interest. Hence, 48 individuals with OSA and skeletal class II high-angle malocclusion were chosen from among all patients in need of orthodontic therapy. Every patients had CBCT (cone beam computed tomography) taken both before and after receiving orthodontic therapy. All parameters were assessed on the lateral cephalogram from CBCT in order to assess the indices of craniocervical posture, hyoid position, skeletal and dental conditions. Parameters of upper airway (position of hyoid) showed statistically significant increase in values after orthodontic treatments. Thus, there was increase in values of dimensions of upper airway, post orthodontic treatment. Hence, orthodontic therapy help improve the upper airway morphology and craniocervical posture in patients of OSA with hyperdivergent skeletal class II malocclusion.


Background:
Obstructive sleep apnea (OSA) can worsen the patient's level of sleep at night and negatively impact a patient's day-to-day activities and work, and increase an adult's chance of developing major systemic disorders, such as diabetes, hypertension and coronary heart disease [1-3].Teens that have restricted airways are more prone to experience emotional turmoil, low performance in school, attention-deficit disorder and hyperactivity, restricted skeletal and physical growth, and cognitive impairment [4][5][6].The most common and the most difficult malocclusions in orthodontics is known as skeletal Class II high-angle malocclusion; it is characterized by vertical excessive growth of the mandible and sagittal inadequate growth [7,8].Patients typically experience limited airways along with unsatisfactory lateral appearances as a result of this malocclusion [9, 10].Any treatment strategy that addresses down skeletal malformation should include forward mandibular rotation (FMR) in order to cope with the multitude of issues associated with hyperdivergent Class II sufferers [11,12].The growth potential of the skeletal effects of orthodontic therapy varies [13,14].The FMR mentioned above causes several growing patients' mandibles to grow more anteriorly, which improves their skeletal facial pattern [15,16].However, only a small number of adult patients have the indicated therapeutic benefits.

Materials and Methods:
48 individuals with OSA and skeletal class II high-angle malocclusion were chosen from among all patients in need of orthodontic therapy between January 2021 and February 2024 for this retrospective analysis.
Inclusion criteria: [1] Patients who are at least eighteen years and above old [2] High-angle pattern (MP-FH angle > 29°) with skeletal Class II malocclusion (ANB angle ≥ 4°) [3] Patients whose treatment included the removal of 2 second premolars in mandible and 2 first premolars of maxilla [4] Patients whose treatment included four bilaterally inserted micro-implants in the mandible and maxilla [5] CBCT scans, both pre-and post-treatment, are accessible

Exclusion conditions in order of presentation:
[1] A history of orthognathic surgery and/or orthodontic therapy [2] Syndrome of temporo-mandibular joint diseases [3] Past surgical upper airway experience [4] Impairment of the function of the lip as well as palate (such as a cleft lip or palate) Following the extraction of their second premolar of mandible and first premolar of maxilla, each patient received a pre-adjusted edgewise appliance with a 0.022-inch slot.The same orthodontist administered local anesthetic before implanting four mini-screws symmetrically through the buccal mucosa in the maxilla and mandible, between the first molars and second premolars.Four weeks following the micro-implant implantation, an elastic chain was used to produce a load of 150 g force.The patient's treatment took place over almost three years, with the goal of treating the Class I molar relation and Class I canine relationship.
Every patient had CBCT taken both before and after receiving orthodontic therapy.All CBCT data were exported in DICOM format and entered into Dolphin Imaging 11.95 software for 3D reconstruction and interpretation.By projecting the 3D reconstruction picture into the midsagittal plane from right to left, all parameters were assessed on the lateral cephalogram from CBCT in order to assess the indices of craniocervical posture, hyoidposition, skeletal and dental conditions.Using Dolphin Imaging software, the airway diameters were compared before and after therapy.The PP plane was aligned parallel to the horizontal plane in all photos to create a standard viewpoint.The upper airway border was defined by all planes corresponding to the PP plane.The laryngopharynx airway (LPA), glossopharynx airway (GPA) and velopharynx airway (VPA) are the three midsagittal portions of the upper airway that were physically separated.After the borders were established, Dolphin software was used to automatically determine the volume as well as minimum areas of LPA, GPA and VPA.

Statistical analysis:
SPSS 26 program was used.The Kolmogorov-Smirnov test was used to evaluate whether the data had a normal distribution.
Using the Wilcoxon signed rank test for non-normally generated variables and the paired t test for normally distributed data; a comparison of the pre-orthodontic treatment and post orthodontic treatment outcome variables was made.Pearson correlation analysis was used to measure items with a normal distribution, and Spearman rank correlation analysis was used to measure items with an irregular distribution.A difference that reached statistical significance was indicated by a p-value of less than 0.05, and the bilateral test level was set at α = 0.05.

Results:
There was statistically significant improvement in most of the variables of craniofacial morphology after orthodontic therapy (Table 1).Parameters of upper airway (position of hyoid) showed statistically significant increase in values after orthodontic treatments (Table 2).There was statistically significant increase in values of dimensions of upper airway, post orthodontic treatment like LPA, GPA, VPA, Min GCSA and Min LCSA (Table 3).However, the values of VCSA didn't increase significantly (Table 3).Values of most of parameters of cervical inclination like increased significantly after orthodontic therapy (Table 4).Craniofacial inclination increased significantly after orthodontic treatment (Table 5).There was statistically significant increase in craniocervical inclination post therapy (Table 6).However, changes to the craniocervical location could affect the way that an organism grows.It was postulated that patients with upper airway obstruction and high angle will extend their cervical column as a whole rather than only extending their head forward in order to achieve enough airflow [11][12][13][14][15][16][17][18].This theory may have its roots in the fact that OSA patients with high angles cannot have their craniofacial and craniocervical postures extended to a large degree without compromising their horizontal visual axis [21-24].Furthermore, this study's findings showed a correlation between the middle cervical column's inclination and the hyoid position parameter.In order to compensate, cervical extension may help move the hyoid bone away from the posterior pharyngeal wall, allowing the blocked airways to be released [25].

Conclusion:
Data shows that orthodontic therapy help improve the upper airway morphology and craniocervical posture in patients of OSA with hyperdivergent skeletal class II malocclusion.

18-24].
There is a connection between both vertical and sagittal skeletal face morphology and craniocervical posture.In actuality, patients in skeletal Class II have a substantially bigger craniocervical angle compared to individuals with Class III due to a more lordotic arc of the backbone and an increased extension of the head [ Individuals with skeletal class II high angles are more likely to develop OSA [17-20].For this reason, orthodontic therapy and upper airway surveillance are essential for individuals with Class II high-angle malocclusion, especially those who are teens [21-24].A state known as craniocervical

Table 6 : Comparison of variables of craniocervical inclination before and after orthodontic
However, less study has been done on the effects of orthodontic therapy on changes in craniocervical posture in class II high-angle patients.It was hypothesized that orthodontic therapy would provide a similar improvement in craniocervical posture and airway in OSA patients with skeletal class II high-To assist explain this phenomenon; a study suggests that the patient's attempt to achieve a broader airway is what leads to the expansion of the craniocervical position [18-24].According to the previously indicated theory, some investigators have reported significant changes in craniocervical posture when airway blockage has been relieved [19-23].