Correlation Between Palatal Depth and Duration of Upper Airway Obstruction Since Diagnosis in Children

Objective: To analyze the correlation between palatal depth and duration of the upper airway obstruction since diagnosis among children with habitual mouth breathing. Material and Methods: This cross-sectional analytical study was conducted using the consecutive sampling method on boys and girls who were habitual mouth breathers and presented with allergic rhinitis, adenoid hypertrophy, obstructive sleep apnea, rhinosinusitis, and nasal polyp. Information about the duration of upper airway obstruction was obtained from the medical records of the patients. The patients divided into two groups: those diagnosed with upper airway obstruction for < 4 years, and those diagnosed with upper airway obstruction for > 4 years. Hard palate measurements were obtained from upper arch study models using a caliper with a precision of ± 0,1 mm. Results: A strong positive correlation was noted between the duration of the upper airway obstruction since diagnosis and palatal depth in children (r=0.623; p<0.05). Furthermore, the depth of the palates was found to be greater than 40 mm when the duration of upper airway obstruction since diagnosis was more than four years. Conclusion: The finding of this study indicates that upper airway obstruction can result in high palates in children with habitual mouth breathing.


Introduction
Craniofacial growth and development can be influenced by the breathing process. Nasal breathing allows for the proper growth of the dentofacial complex. According to the functional matrix theory by Melvin Moss, facial growth occurs as a response to functional needs such as breathing, sucking, chewing, and swallowing. Additionally, nose breathing can stimulate lateral growth of the maxilla and lower the palatal vault [1,2].
Upper airway obstruction refers to a blockage in nasopharynx or oropharynx areas. In children, the causes of upper airway obstruction are adenoid hypertrophy, allergic rhinitis, obstructive sleep apnea, nasal polyp, and rhinosinusitis, resulting in habitual mouth breathing [2,3].
The effects of this breathing habit on maxillary growth are a long and narrow face, short upper lip, prominent maxillary incisors, narrow V-shaped upper arch with high palatal vault, and class II occlusal relationship [3,4].
A few studies have reported the relationship between respiratory problems and maxillary growth. A previous study showed a narrowing of the palate in the posterior region as a result of mouth-breathing [5]. Similar results were reported in another study along with the presence of significantly deeper palate in children with allergic rhinitis [6]. However, to the best of our knowledge, there were no studies on the effect of the duration of upper airway obstruction and palatal depth.
The aim of this study was to determine the correlation between palatal depth and the duration of upper airway obstruction in children.

Study Design and Sample
In this cross-sectional and analytic study, a consecutive sampling method was used on boys and girls with allergic rhinitis, adenoid hypertrophy, obstructive sleep apnea, rhinosinusitis, and nasal polyp.
The inclusion criteria were: boys or girls with mouth-breathing habit due to allergic rhinitis,

Results
A strong positive correlation between palatal depth and duration of upper airway obstruction since diagnosis was noted (r=0.623; p<0.05). As shown in Figure 1, the depth of the palate was greater than 40 mm when the duration of upper airway obstruction since diagnosis was more than four years. adenoid hypertrophy, rhinosinusitis, obstructive sleep apnea, and nasal polyp [8,9]. The obstruction of the upper airway promotes the habit of mouth breathing in children leading to muscular and postural changes that may result in dento-skeletal changes [3,4].

Duration upper airway obstruction since diagnosis
In the present study, a strong and positive correlation was noted between the palatal depth and duration of upper airway obstruction since diagnosis. The previous study has demonstrated a relationship between upper airway obstruction and palatal depth statistically significant differences between obstructive sleep apnea and control subjects [10].
Nasal breathing stimulates the lateral growth of the maxilla and lowers palatal vault.
Additionally, it influences the development of craniofacial structure, favoring the harmonious growth and development along with the function of swallowing and mastication [11]. During the growth and development of the nasomaxillary complex, the growth of maxilla can be influenced by the growth of the cartilaginous of the nasal septum. Palatal growth occurs by the deposition on the palatal roof and apposition on the nasal floor [12].
Mouth breathing induces the development of a high palatal vault because the absence of negative pressure in the nasal cavity prevents the lowering of the palate. Moreover, the low position of the tongue in the oral cavity creates an unbalance between lateral buccal and lingual muscular forces, resulting in a narrow and V-shaped palatal vault [13,14]. In view of manifestation in the craniofacial complex as a result of habitual mouth breathing, multidisciplinary teamwork is required.
Furthermore, orthodontic treatment is needed for occlusal adjustment. Limitation of this present study is lack of mouth breathers subjects, further investigation of palatal depth in mouth breathers caused by airway obstruction is required with more number of subjects.

Conclusion
Nasal breathing facilitates the normal growth and development of the craniofacial complex.
Any obstruction in the upper airway passages may result in dentofacial and skeletal alterations. In the present study, children with habitual mouth breathing due to upper airway obstruction presented with narrow and V-shaped palates. A strong positive correlation between palatal depth and duration upper airway obstruction since diagnosis was noted. Moreover, children who had upper airway obstruction for more than four years since diagnosis presented with deeper palates.
Authors' Contributions: AK designed the study, performed the data collection, data analysis and interpretation, and wrote the manuscript. SBD and DBS designed the study, performed the data collection, data analysis and interpretation, wrote the manuscript and reviewed the manuscript. All authors declare that they contributed to critical review of intellectual content and approval of the final version to be published.
Financial Support: None.

Conflict of Interest:
The authors declare no conflicts of interest.