2019, Number 4
Cephalometric changes of upper airway posterior to rapid palatal expansion with and without facial mask
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ABSTRACT
Introduction: The maxilla is a bone that is related to different adjacent structures, its correct formation and development is of great importance because the presence of alterations during growth can cause deficiencies in a transverse and sagittal sense. These deficiencies detected in time can be corrected by using orthopaedic devices that modify not only the structure of the maxilla, but can also influence the morphology of the upper airway. Objective: Evaluate the morphological changes of the airway, after rapid palatal expansion treatment with and without maxillary protraction in growing patients. Material and methods: 32 patients from eight to 14 years old were examined and divided into two groups: G1 used facial mask and Hyrax type expander; G2 used Hyrax type expander only. Cephalometry of the upper airway was performed before and after being treated by palatal disjunction and maxillary protraction, to evaluate changes in the airways. Results: Using the t-Student test, significant changes were observed in the dimension of the upper and middle pharyngeal airway in group 2, while for group 1 there were no significant changes in the dimension of the upper, middle and lower pharyngeal airway. Conclusion: Treatment of rapid palatal expansion with the Hyrax type expander, in addition to its main use as a transverse malocclusion corrector, has positive repercussions on the sagittal dimension of the pharyngeal airway.INTRODUCTION
The upper jaw is one of the most important bones in the facial mass and is closely related to different structures such as the mandible, tongue, pharynx, muscles, and airways.
Transverse malocclusions of multifactorial origin are anomalies that can be observed from an early age in patients. Currently, there are several methods and treatments to correct this problem, one of them being rapid maxillary expansion (RME).1
Within the aetiopathogenesis of this transverse dysmorphia, there are genetic conditioning factors that can be associated with a lack of maxillary development, an excess of mandibular development, a combination of both, and in rare cases an excess of maxillary development. Transverse malocclusion of dentoalveolar origin is another factor that occurs at an early age and usually occurs in conjunction with the type of anomaly that affects the bony base.1-3
There are also habits that can trigger this developmental anomaly such as oral breathing. This condition is classified as a habit when the nasal obstruction problem is resolved and the patient continues to breathe through the mouth at an early age. This type of breathing has a series of repercussions at a general level and in maxillofacial development, such as underdevelopment of the upper jaw, which can be global or only transverse. Another habit that forms part of the etiology of this malformation is infant swallowing. In the early stage of life, a low tongue position is normal and physiological for swallowing liquid or semi-solid food. Maintaining this type of swallowing when it is required to move to an adult swallow, where the tongue must rest on the palate, causes transverse alterations of the maxillary bone, since the tongue does not exert pressure against the palate and the buccinator muscle continues to compress the maxilla.2
There are sucking habits that can lead to skeletal malformations, which repercussions on the transverse development of the jaw are similar to those of atypical swallowing, as they come from a low tongue.2
Since ancient times, attempts have been made to correct malocclusions in subjects with them. In the 19th century, the methods for carrying out RME were already being studied. This term was first introduced by WH Dawernell in 1857, cited by Staples, and confirmed by Angell in 1860.4 These older systems were not very successful and fell into disuse, but in recent decades these procedures have been revived as important tools in early orthodontic/orthopaedic treatment.5,6
RME consists of the orthopaedic separation of the palate at the mid-palatal suture, if a rapid force is applied to the posterior teeth, there will not be enough time for these teeth to tilt, and the force, instead of being exerted on these teeth, it will be transferred to the palatal suture, while the palatal suture will be opened, and the teeth displacement will be minimal. The level of separation that can be achieved with this technique is 0.2 to 0.5 mm per day.7
Rapid palatal expansion (RPE) has been used over time for the correction of posterior crossbites as it has been shown to influence nasal morphology and breathing patterns. This expansion is most commonly performed at the beginning of interceptive orthodontic treatment.8,9
Class III malocclusion is a type of dental occlusion characterized by a more advanced position of the mandible in relation to the maxilla that can present in five forms: mandibular hyperplasia, mandibular hypoplasia, combination of both, dental, and functional.
The face mask protraction is an orthopaedic appliance used in patients with skeletal class III. It is a device capable of redirecting the growth of the maxilla horizontally, and when combined with an expander appliance such as the Hyrax, optimal and controlled movement in all three planes of space is achieved. This expansion appliance is used in conjunction with the face mask for two main reasons, the first, is because in skeletal Class III there is usually a transverse collapse of the maxilla, and the second, is that by separating the mid palatal suture, we are facilitating the protraction of the maxilla horizontally.10
MATERIAL AND METHODS
The present study was carried out at the teaching clinic of the graduate Department of Orthodontics and Children's Dentistry of the Autonomous University of Coahuila. From the existing records were selected medical files of patients were treated with a facial mask and Hyrax-type expander or exclusively with Hyrax that were not more than one year old at the start of the treatment. The records of 46 patients were collected. After applying the exclusion and elimination criteria, a final sample of 32 patients with an age range from eight to 14 years was obtained.
The sample was divided into two groups, group 1 was treated with a facial mask and Hyrax expander, and group 2 was treated with a Hyrax expander only. The first group consisted of 14 patients, eight males, and six females, with an average age of 11.5 years. The second group consisted of 18 patients, 12 females, and six males, with an average age of 12 years. The initial pre-procedure lateral skull radiograph was obtained from the file, and then a new final post-treatment lateral radiograph was requested. Both radiographs were taken with MORITA Veraviewpocs 2D X550 model 2DB® radiographic equipment with a panoramic and cephalometric sensor. The lateral skull radiographs were taken in a natural position of the head, lips relaxed and in centric relation by the same radiologist technician from said institution.
The exclusion and elimination criteria were, lateral skull radiographs that had not been taken with the faculty's equipment, patients outside the established age range, expansion had been completed more than one year ago, expansion had been performed with another type of expander device, incomplete records, poorly taken radiographs, poor digital imaging.
The Dolphin Imaging 11.9 Premium® digital cephalometric tracing software was used for the cephalometric analysis, and these underwent the Quas/Airway cephalometric study, all by the same operator, in which the upper (SPAS line), middle (MAS line), and lower (IAS line) pharyngeal airway were assessed before and after treatment (Figure 1).11
After data collection, the data were recorded on a control sheet and tabulated in an Excel spreadsheet. For statistical analysis, the t-Student test was performed using IBM SPSS v. 19.
RESULTS
In group 1 of patients treated with face mask and Hyrax-type expander, the initial length of the upper, middle, and lower airway averaged 11.28 mm, 9.57 mm, and 12.35 mm respectively, and the final measurement of the upper, middle, and lower airway averaged 12.7 mm, 9.34 mm and 12.75 mm respectively. Although changes in the initial and final measurements were observed in this group of patients, no statistically significant differences were found (p > 0.05) (Figure 2).
In group 2 of patients treated with Hyrax expander alone, initial upper, middle, and lower airway lengths averaged 10.25 mm, 8.59 mm, and 11.7 mm respectively, and final post-treatment measurements averaged 11.54 mm, 9.6 mm, and 12.3 mm respectively. In this group, there were changes in length, the upper and middle airway showed statistically significant differences with a value (p < 0.05), while the lower airway did not show such a difference (Figure 3).
DISCUSSION
The use of orthopaedic appliances such as the Hyrax expander has secondary effects on structures adjacent to the maxilla, such as the upper airway. In this study, the use of the Hyrax in conjunction with the protraction mask did not have a direct impact on the upper airway; on the contrary, the isolated use of the Hyrax expander to correct a transverse problem had a direct impact on the upper and middle airway.
Barreiro evaluated upper airway changes with class III orthopaedic treatment in 30 class III patients (nine girls and 21 boys) with a mean age of 6.59 years who presented with mandibular retrognathism and used a McNamara disjunctor and face mask for 18 months. The results observed on the lateral skull radiograph showed that the upper airway increased by 2.58 ± 2.30 mm, the middle airway increased by 2.39 ± 2.30 mm, and the lower airway increased by 2.39 ± 2.30 mm, also considered significant.12 This study differs from these results as no significant changes were found in the nasopharynx, oropharynx, and hypopharynx of our patients treated with face masks and palatal expander, which may be attributed to the sample size and average ages assessed, which are different between the two studies.
Fitin Aloufi et al., evaluated 30 patients with an average age of 14 years with maxillary compression and compared them with a control group of similar age without maxillary compression. It was measured the upper and lower airway using McNamara cephalometric analysis, before and after expansion, and obtained statistically significant values for the upper airway measurement but did not obtain statistically significant values for the lower airway.13 Those results are similar to ours, since the sample and type of measurement was very similar to this research.
CONCLUSION
The Hyrax-type expander used to correct transverse malocclusions generates a change in the structures that make up the airway in an anteroposterior direction, specifically in the upper and middle pharyngeal airway in growing patients, in contrast to treatment with a facial mask and Hyrax-type expander.
The face mask used in conjunction with the Hyrax-type rapid palatal expander, despite aiding maxillary development, does not cause significant changes in the structures that make up the upper, middle, and lower airway in growing patients.
It is recommended to extend the study sample and to follow up the patients who used Hyrax to evaluate over time, whether or not there is a change in relation to growth.
REFERENCES
AFFILIATIONS
1 Maestría en Ciencias Odontológicas con Acentuación en Ortodoncia. Facultad de Odontología de la Universidad Autónoma de Coahuila, Unidad Torreón. México.
CORRESPONDENCE
Eduardo Pérez Maldonado Barragán. E-mail: eduardopmb@outlook.comReceived: Junio 2020. Accepted: Agosto 2020.