|Year : 2021 | Volume
| Issue : 2 | Page : 125-129
Correlating angular nasal parameters with skeletal malocclusion
Pushkar Andhare, Sanjeev Datana, Shiv Shankar Agarwal, SK Bhandari
Department of Dental Surgery and OHS, AFMC, Pune, Maharashtra, India
|Date of Submission||13-May-2020|
|Date of Decision||25-Jul-2020|
|Date of Acceptance||26-Nov-2020|
|Date of Web Publication||17-Sep-2021|
Department of Dental Surgery, AFMC, Pune, Maharashtra
Source of Support: None, Conflict of Interest: None
Introduction: Human nose exhibits unique features and variations in response to various influencing factors. To establish the correlation between these nasal features and type of malocclusion, a study was formulated with aim to assess the nasofacial, nasolabial, and nasomental angles in various sagittal and vertical types of malocclusion.
Materials and Methods: A study sample of 410 patients was selected from patients undergoing orthodontic treatment at the department to assess various nasal angular parameters. Data were divided into groups depending upon type of malocclusion and were subjected to suitable statistical analyses.
Results: The mean nasofrontal angle was highest in Class I malocclusion (P < 0.05) and normodivergent patients. The mean nasolabial angle was highest in Class III malocclusion and hyperdivergent patients (P > 0.05). The mean nasomental angle was significantly higher in Class II malocclusion and hyperdivergent (P < 0.05). Columellar alar angle and nares axis angle showed significant positive correlation with each other but not with dorsum–base ratio.
Conclusion: The nasal angular parameters show peculiar features in different types of malocclusion in sagittal and vertical planes. Hence, its clinical significance in orthodontic diagnosis and treatment planning needs to be deliberated to obtain a substantial esthetic outcome.
Keywords: Maharashtra, nasal angular parameters, type of malocclusion
|How to cite this article:|
Andhare P, Datana S, Agarwal SS, Bhandari S K. Correlating angular nasal parameters with skeletal malocclusion. J Dent Def Sect. 2021;15:125-9
| Introduction|| |
The human face is considered as an important interface for social interaction, decided by underlying traits and characteristics. The soft tissue paradigm in orthodontics dwells upon achieving harmonious profile, with the aim to achieve stable treatment results. The soft tissues are the anatomical limits to dental and skeletal changes that are planned by orthodontic/dentofacial orthopedic or ortho-surgical treatment, and variation in the thickness of this soft tissue can be an important factor while planning for an individual case. The facial harmony is determined by the morphologic relation and proportions among nose, lips, and chin. Nose, being prominent part of the face along with its central location, contributes to uniqueness of facial appearance of an individual.,
A surfeit of information is available in the literature on the nasal and facial morphological features, employing different linear/angular measurements or ratios. However, these parameters have complex interaction with each other along with various other factors, much of which lies unexplored.
Therefore, a study was planned with an aim to assess the different angular parameters to analyze nasal morphology and to correlate with the different skeletal malocclusion prevalent.
| Materials and Methods|| |
This cross-sectional observational study was conducted at the Department of Orthodontics and Dentofacial Orthopaedics of a Government Institute. Ethical clearance was obtained from the institutional ethical committee, and written consent was obtained from all participants. The study sample was selected after applying the following criteria:
- Young patients aged 12–25 years, without gross asymmetry of face/nose. Patients with a negative history of nasal trauma or nasal surgery.
- Patients with cleft lip and palate or diagnosed with syndrome affecting the nasal structures.
A total of 410 patients meet the inclusion and exclusion criteria and were selected for the study. Anthropometric measurements and pretreatment orthodontic records were assessed for the patients selected. The various morphological nasal parameters assessed during the present study include nasal length, nasal width, and nasal angular parameters such as nasofrontal angle, nasolabial angle, nasomental angle, columella alar angle, and nares axis angle. The sample was grouped depending upon the type of skeletal malocclusion in the sagittal and vertical planes. Linear nasal anthropometric measurements were recorded using a digital vernier caliper, sensitive up to the first decimal point. Angular nasal parameters were assessed on the digital photographs of the patients obtained with standardized orthodontic protocol, employing Adobe Photoshop software version 2018CC (Adobe Inc., for Windows).
The following nasal parameters were assessed [Figure 1]a, [Figure 1]b, [Figure 1]c:
|Figure 1: (a) Nasal parameters: 1 - Nasal length, 2 - Nasal width (dorsum–base ratio = Nasal width/Nasal length). (b) Angular nasal parameters: 1 - Nasofrontal angle, 2 - Nasomental angle, 3 - Nasolabial angle. (c) Angular nasal parameters: 1 - Nares axis angle, 2 - Columella-alar angle|
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- Nasal length: Measured from soft tissue nasion to pronasale
- Nasal width: Distance measured between most convex point of ala on both sides (inter alar width)
- Dorsum–base ratio (nasal width to nasal length ratio): determined by the mathematical formula – nasal width/nasal length
- Nasofrontal angle: Drawing a line tangent to the glabella through the nasion that will intersect a line drawn tangent to the nasal dorsum
- Nasolabial angle: Angle formed by a line that lies tangent to the most anterior point of the columella and tangent to the mucocutaneous border of the upper lip, which intersect at subnasale
- Nasomental angle: angle formed by a line drawn through the nasal dorsum intersecting a line drawn from the nasal tip to the soft tissue at the pogonion
- Columella alar angle: angle formed with its vertex at the base of the columella and the lateral lines tangent to the caudal ala
- Nares axis angle: angle formed by the intersection of long axis of the nares.
The assessment of the skeletal malocclusion in sagittal and vertical planes was done by determining the ANB angle and Frankfort mandibular plane angle (FMA), respectively, on lateral cephalogram of the patient. Patients were grouped according to the skeletal malocclusion in the sagittal plane as skeletal Class I (ANB = 0°–4°), skeletal Class II (ANB >4°), or skeletal Class III (ANB < 0°). Patients were also grouped according to the skeletal malocclusion in the vertical plane as normodivergent (FMA = 22°–25°), hypodivergent (FMA < 22°), or hyperdivergent (FMA > 25°).
Fifty cases randomly selected were reassessed by primary author at an interval of 3 weeks and also reviewed by a senior orthodontist, to prevail over inter- and intra-examiner bias.
The categorical variable data are presented as n (% of cases) and its distribution was statistically evaluated using Chi-square test. Continuous variables of the data are represented as mean and standard deviation; independent sample t-test was used for comparison of distribution statistically for two groups; and for more than two groups, analysis of variance was used. Pearson's technique was employed for correlation analysis. Scatter diagrams and line of regression were used to study the linear relationship of the variables. P < 0.05 was considered to be statistically significant. Two-tailed alternative hypothesis (hypothesis of no difference) was formulated against each null hypothesis. The data collected were statistically analyzed using Statistical Package for the Social Sciences (SPSS) (SPSS version 22.0, IBM Corporation, Armonk, New York, USA) for MS Windows.
| Results|| |
The inter-and intra-examiner recordings did not show any significant difference (κ = 0.8). On evaluating the study sample, it was observed that 28% (n = 115) of patients exhibited skeletal Class I malocclusion, 59.7% (n = 245) exhibited skeletal Class II malocclusion, and only 12.3% (n = 50) exhibited skeletal Class III malocclusion; further, it was observed that 35.4% (n = 145) showed normodivergent facial type, 52.3% (n = 215) showed hypodivergent facial type, and only 12.3% (n = 50) showed hyperdivergent facial type.
The mean nasofrontal angle was highest in Class I malocclusion patients, followed by Class III malocclusion patients, which was statistically significant (P < 0.05). The mean nasolabial angle was highest among Class III malocclusion patients but did not differ significantly (P > 0.05). The mean nasomental angle was significantly higher in Class II malocclusion patients as compared to Class I and Class III malocclusion patients (P < 0.05) [Table 1] and [Figure 2].
|Table 1: Distribution of mean nasofrontal, nasolabial, and nasomental angles according to type of malocclusion in sagittal plane|
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|Figure 2: Distribution of mean nasofrontal, nasolabial, and nasomental angles according to type of malocclusion in the sagittal plane|
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The mean nasofrontal angle was found to be higher among normodivergent patients as compared to hypodivergent and hyperdivergent patients but did not differ significantly (P > 0.05). The mean nasolabial angle was largest in hyperdivergent patients but did not differ significantly (P > 0.05). The mean nasomental angle was significantly larger in hyperdivergent patients as compared to hypodivergent and hyperdivergent patients (P < 0.05) [Table 2] and [Figure 3].
|Table 2: Distribution of mean nasofrontal, nasolabial, and nasomental angles according to type of malocclusion in vertical plane|
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|Figure 3: Distribution of mean nasofrontal, nasolabial, and nasomental angles according to type of malocclusion in the vertical plane|
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Columella alar angle showed statistically significant positive correlation with nares axis (P < 0.01). Columella alar angle and nares axis angle did not show statistically significant correlation with dorsum–base ratio (P > 0.05) [Table 3] and [Figure 4]a, [Figure 4]b, [Figure 4]c.
|Table 3: Correlation analysis between columella alar angle, nares axis, and dorsum-base ratio|
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|Figure 4: (a) Scatter diagram showing correlation analysis between columella alar angle and nares axis angle. Line of regression depicting the extent of linear relationship along with R2 value is also shown in the figure. (b) Scatter diagram showing correlation analysis between columella alar angle and dorsum–base ratio. Line of regression depicting the extent of linear relationship along with R2 value is also shown in the figure. (c) Scatter diagram showing correlation analysis between nares axis angle and dorsum–base ratio. Line of regression depicting the extent of linear relationship along with R2 value is also shown in the figure|
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| Discussion|| |
It is evident in the literature that nasal morphological features are influenced by genetic and environmental factors, and it is important to understand the influence of these factors on growth and development of the nose. Change in the position of maxillary incisors/maxilla by orthodontic/orthopedic treatment or ortho-surgical procedure will result in a change in nasal parameters. Hence, the detailed knowledge of growth and development along with variation in nasal parameters among individuals with different skeletal features (malocclusion in the sagittal or vertical plan) will help orthodontist to visualize the treatment outcome and to customize the treatment plan. To enhance the existing knowledge on the subject, a study was planned to establish correlation between different nasal parameters and the prevalent skeletal malocclusions.
Nasal parameters with angular measurements have been studied by different authors separately in sagittal skeletal malocclusion and vertical facial patterns. Jafarpour et al. have explored the angular measurements of nose and showed vide variation with respect to malocclusion in the sagittal plane. Similar results have been obtained in the present study, where a statistically significant difference in angular parameters has been reported among different sagittal skeletal malocclusions studied. Nehra and Sharma correlated the nasal parameters with malocclusion in vertical plane and found inter-relation between upper component of nasolabial angle and vertical maxillary discrepancies. In the present study, a wide variation was observed among the different facial patterns; however, the results obtained were not statistically significant. In the present study, statistically significant larger values of nasomental angle were observed among skeletal Class II malocclusion compared to other malocclusions studied. This finding is not in accordance with the previous study, where Thakur et al. observed a negative correlation among angle ANB and nasomental angle. This variation can be explained on the basis of variation in nasal morphology among different races and individuals with different ethnicity.
The nasolabial angle observed in the present study showed higher value with skeletal Class III patients as compared to Class II and Class I; this is in line with the previous study by Robison et al., who found a highly significant negative correlation between nasolabial angle with skeletal anteroposterior relation. Similarly, for nasofacial angle, a negative correlation with anteroposterior skeletal relation has been observed in the previous study; however, in the present study, the distinct result has been observed.
The currently available literature fails to yield any study that has attempted to establish correlation between columella alar angle, nares axis angle, and dorsum–base ratio, thus leaving no scope for comparison and justification of the results obtained. However, the present study could find a significant positive correlation between columella alar angle and nares axis angle but not with the dorsum–base ratio, making it essential to cautiously interpret the clinical significance of the result.
| Conclusion|| |
Different angular nasal parameters are routinely used in orthodontic diagnosis and treatment planning. The parameters studied in our study showed significant variation in terms of type of malocclusion in both sagittal and vertical plane. The nasolabial angle and nasomental angle are the two parameters that showed the most significant difference. Although the statistical significance among parameters studied has been noted, the clinical significance of the same needs to explore in clinical settings. Therefore, similar studies with large sample and with even distribution among the type of malocclusions are recommended.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2], [Table 3]