Journal of Pharmacy And Bioallied Sciences

ORIGINAL ARTICLE
Year
: 2020  |  Volume : 12  |  Issue : 5  |  Page : 161--167

Airway analysis in skeletal Class I and Class II subjects with different growth patterns: A 2D cephalometric study


Swaroopa R Ponnada1, Vivek R Ganugapanta2, Kiran K Perumalla3, Mohammed A Naqeed4, T Harini5, Shiva Praasad Mandaloju6,  
1 Department of Orthodontics, Panineeya Mahavidyalaya Institute of Dental Sciences, Hyderabad, Telangana, India
2 Department of Orthodontics, Narayana Dental College, Nellore, Andhra Pradesh, India
3 Department of Orthodontics, Mamatha Dental College, Andhra Pradesh, India
4 Private Practitioner, Hyderabad, Telangana, India
5 Bhaskara College, Hyderabad, Telangana, India
6 Department of Orthodontics, Lenora Institute of Dental Sciences, Andhra Pradesh, India

Correspondence Address:
Swaroopa R Ponnada
Department of Orthodontics, Paninneya Mahavidyalaya Institute of Dental Sciences, Kamala Nagar, Dilsukhnagar, Hyderabad 500060, Telangana
India

Abstract

Objective: A two-dimensional cephalometric study was carried out to assess the airway among individuals with Class I and Class II skeletal base. Materials and Methods: Class II subjects were further categorized into horizontal and vertical growers and average growth patterns to check the possible relationship between the facial skeleton and pharyngeal airway. Lateral cephalograms of 150 subjects were obtained using standard protocol in natural head position (NHP). Nasopharyngeal and oropharyngeal linear, and angular and nasopharyngeal area measurements were obtained using standardized tracing technique. Analysis of variance (ANOVA), level of significance, and post hoc Turkey’s test were performed to assess the correlation between skeletal pattern of the individual and airway dimension. Gender discrimination was assessed using independent sample t test. Results: In linear measurements, significant differences were observed among upper pharynx (0.039), adenoid tissue 1 (0.036), and adenoid tissue 2 (0.01). In angular measurements, differences were observed with angle of nasopharynx (0.008). The nasopharyngeal area measurements were also associated with significant difference (0.038) with Class II vertical growers less than those with Class I average and Class II horizontal groups. Conclusion: Class II vertical growers had significantly reduced nasopharyngeal airways.



How to cite this article:
Ponnada SR, Ganugapanta VR, Perumalla KK, Naqeed MA, Harini T, Mandaloju SP. Airway analysis in skeletal Class I and Class II subjects with different growth patterns: A 2D cephalometric study.J Pharm Bioall Sci 2020;12:161-167


How to cite this URL:
Ponnada SR, Ganugapanta VR, Perumalla KK, Naqeed MA, Harini T, Mandaloju SP. Airway analysis in skeletal Class I and Class II subjects with different growth patterns: A 2D cephalometric study. J Pharm Bioall Sci [serial online] 2020 [cited 2021 Apr 22 ];12:161-167
Available from: https://www.jpbsonline.org/text.asp?2020/12/5/161/292874


Full Text



 Introduction



The pharynx comprises nasopharynx and oropharynx. They carry out of the two important functions of stomatognathic system called respiration and deglutition efficiently and in unison.[1] The close relationship between the pharyngeal structures and the dentofacial complex pattern therefore attracts the orthodontist’s attention.[2],[3]

Cephalometrics is an important diagnostic tool in orthodontics and helps for analyzing craniofacial complex for anatomic and spatial variations, thereby helping in diagnosis and treatment planning of the subject in question. Cephalometrics has been considered as the most widely used imaging and diagnostic modality in literature.[4]

There has been always a controversial debate between the airway obstruction and dentofacial developmental pattern. Watson et al.[5] studied relation between malocclusion and airway obstruction and concluded that no association existed between aforesaid parameters. Aronson[6] found positive correlation between craniofacial skeleton and airway adequacy carried out by rhinomanometric measurements. Hence, this study was undertaken to test whether there is any association between pharyngeal airway and type of malocclusion.

Aims and objectives

The aims of this study were to assess the airway dimensions in skeletal Class I and Class II individuals, and to evaluate the relationship between airway and growth pattern.

 Materials and Methods



The sample consisted of 150 subjects with age group of 17–25 years.

Patients enrolled in the present investigation were categorized based on cephalometric measurements for skeletal base and growth pattern. For assessing the anteroposterior jaw relations, ANB angle[1] and Beta angle[7] were considered. On the basis of these parameters, the sample was categorized into skeletal Class I and Class II. For assessing the growth pattern, FMA and Go-Gn-SN were chosen and were applied for Class II sample to categorize into horizontal and vertical growers.[8] Each group was further subdivided into males and females.

The groups include the following:

Twenty-five female subjects with skeletal Class I with average growth pattern

Twenty-five male subjects with skeletal Class I with average growth pattern

Twenty-five female subjects with skeletal Class II with horizontal growth pattern

Twenty-five male subjects with skeletal Class II with horizontal growth pattern

Twenty-five female subjects with skeletal Class II with vertical growth pattern

Twenty-five male subjects with skeletal Class II with vertical growth pattern

The inclusion criteria of the study included normal healthy subjects without clinical signs and symptoms of pharyngeal pathology and no prior history of orthodontic treatment.

Methods

The study was explained to all the subjects and informed consent was obtained. Digital cephalograms were obtained using a standardized technique.

Standardization for obtaining digital cephalogram

All the lateral cephalograms were recorded in natural head position (NHP). A mirror was placed one and half feet away from the cephalostat and the subject’s head was secured in cephalostat (Orthophos XG5/DR5/CEPH from Sirona, The Dental Company, New York, USA) and was asked to look into his own eyes with lips relaxed. The subject was also asked to clench on the posterior teeth adopting the position they normally show during the day. A bead line was hung from the roof of the cephalostat. The exposure parameters of the lateral cephalogram included exposure time: 9.4s, voltage: 73kV, and current: 15 mA.

Exposure is carried out following forceful expiration before next inspiration.[9],[10] The subjects were instructed not to move the tongue and head and not to swallow during exposure. All the cephalograms were exposed with same exposure parameters and using the same machine.

The tracings were carried out by single calibrated examiner. Nasopharyngeal linear ([UP], [LP], [AD1], and [AD2]) [Figure 1] and [Figure 2], angular (saddle angle, angle of nasopharynx and vertical angle of nasopharynx) [Figure 3], and areal measurements [Figure 4] were calculated. The area of the bony nasopharynx is a trapezoid formed by the following planes:{Figure 1} {Figure 2} {Figure 3} {Figure 4}

AA-PNS

Ba-N

Palatal plane

Pterygoid vertical

The trapezium is formed by superiorly by Ba-N plane; inferiorly by palatal plane extension; anteriorly by pterygoid vertical and posteriorly by Atlas Anterior line (AA). The area of the adenoid tissue contained within the trapezoid depicts the nasopharynx.[11]

Formula for calculating the area of naos pharynx is as follows: NP area = d [h – dtanϴ/2].

The cephalograms were also traced for oropharyngeal linear measurements (MPW, TPPW, and LPW) [Figure 5]. In total, 10% of the lateral cephalograms were retraced after 1 week to check for intra-examiner reliability.{Figure 5}

All the analysis was performed using Statistical Package for the Social Sciences (SPSS) software program, version 14.0. Intergroup comparisons were performed using analysis of variance (ANOVA) test. If P value was significant, then a post hoc Turkey’s test was performed to check which two groups were statistically different from each other. A value of P < 0.05 was set to be statistically significant.

 Results



Nasopharyngeal measurements

In linear measurements, statistically significant differences were observed in the values of upper pharynx (UP), adenoid tissue 1 (AD1), and adenoid tissue 2 (AD2) with Class II vertical group less than those with Class I average group with P = 0.039, 0.036, and 0.01, respectively [Table 1].{Table 1}

In angular measurements, the significant differences were found in angle of nasopharynx and saddle angle with Class II group less than those with Class I average group with P = 0.008 and 0.0190, respectively [Table 2].{Table 2}

The areal measurements revealed vertical group values being less than those with Class I average group and Class II horizontal groups (P = 0.038) [Table 3].{Table 3}

Oropharyngeal measurements

No statistically significant differences were observed in any of the parameters as tested by ANOVA [Table 4].{Table 4}

No gender differences were observed following independent t test [Table 5][Table 6][Table 7].{Table 5} {Table 6} {Table 7}

 Discussion



The higher frequency of nasopharyngeal obstruction in growing children and the association of it to the growth of craniofacial skeleton demands for an economical, easily assessable, simple tool to diagnose the airway obstruction. The adenoid size when assessed using lateral cephalograms was found to have clinically useful correlations particularly with respect to area measurements.[12],[13]

Lateral cephalograms of all the subjects were obtained in NHP with subjects standing in orthoposition.[14],[15],[16] Cooke and Wei[17],[18],[19] also stated that NHP reproducibility was better with mirror method. The exposure was carried out at the end of expiration before next inspiration as this method has the added advantage of recording airway better because during quiet breathing airway resistance is greater during expiration than inspiration.[9],[10]

The use of lateral cephalometric radiographs to evaluate the airway is to an extent compromised as we are trying evaluate the complex three-dimensional (3D) structure of pharynx using 2D imaging.[18] Malkoc et al.[20] stated that “if certain technical requirements are fulfilled such as maintaining NHP, lateral cephalometry can provide useful information in estimating tongue and nasopharyngeal volume.” This observation was also made by Handelman and Osborne,[11] who found that lateral cephalograms give a decent picture of pharyngeal airway size among children of all age groups.

Class II vertical growers had significantly narrower upper pharyngeal airways than Class I average and Class II horizontal growers, confirming previous results in the literature of de Freitas et al.[8] and Dunn et al.[21] Analyzing these results, inference can be drawn that upper airway width is influenced by craniofacial growth.[21] The results of other linear nasopharyngeal measurements such as AD1 and AD2 also showed that individuals with Class II vertical growth pattern had significantly lesser values than Class I average and Class II horizontal growers [Table 1]. This was in accordance with the results of the studies of Martin et al.[14] No statistically significant difference was observed in lower pharynx values among the three groups. With respect to the angle of nasopharynx, Class II group had significantly lower values than Class I average group. No statistically significant differences were observed in relation to depth of nasopharynx among the three groups [Table 2].

The comparison of mean nasopharyngeal area values showed that subjects with Class II vertical growth pattern had significantly lower values compared to Class I average group [Table 3]. The comparison of mean oropharyngeal linear measurements showed that there were no statistically significant differences among the three groups [Table 4]. This is in accordance with the study of Ucar and Uysal,[22] on orofacial dimensions in different growth patterns. Linder-Aronson and Leighton[23] and Daraze et al.[24] suggested that “oropharyngeal space appears to be larger than normal when the nasopharyngeal airway is smaller,” although they did not evaluate this correlation directly.

The sample was also analyzed for gender discrimination in pharyngeal airways. No statistically significant differences were observed in nasopharyngeal and oropharyngeal measurements among the three groups.

 Conclusion



The following conclusions can be drawn from this study:

Class II vertical growers have less nasopharyngeal linear measurements (UP, AD1, and AD2) than Class I average growers.

Class II vertical growers have less nasopharyngeal angular measurements (angle of nasopharynx) than class I average growers.

Class II vertical growers have less nasopharyngeal area than Class I average growers and Class II horizontal growers.

No statistically significant differences were observed in oropharyngeal linear measurements among the three groups.

No gender differences were observed in any of the parameters among the three groups.

Short comings of the study

The sample has been restricted to Class I and Class II groups. The sample can be broadened to include Class III subjects also.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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