Correlation between cephalometric nasal changes and patients’ perception after orthognathic surgery

Introduction

The purpose of this study was to evaluate the correlation between cephalometric measurements and patients’ perception of nasal changes in those with Class III malocclusion who had undergone orthognathic surgery.

Methods

Eighty-five patients (36 men and 49 women) who received maxillary advancement with (group 1) or without (group 2) maxillary impaction were included in this study. Lateral cephalometric radiographs taken before and at the end of the treatment were analyzed. The patients were given an esthetic evaluation form and asked to evaluate their own noses on the Likert scale (subjective perception), while at the same time, they were asked to evaluate profile silhouettes without knowing that it was their own profile (objective perception). The changes and correlations between the cephalometric measurements and the scores obtained from the esthetic perception questionnaire were evaluated statistically.

Results

Postoperative nasal tip inclination and rotation, nasofacial angle, and sagittal position of pronasale had increased significantly ( P <0.05), whereas nasal tip protrusion, nasofrontal angle, and vertical position of pronasale had decreased ( P <0.05). The change in the nasolabial angle and vertical position of pronasale was statistically different between the 2 surgical groups ( P <0.05). In the end, a significant increase was observed in the patients’ objective nasal esthetic scores ( P <0.05).

Conclusions

Soft tissues are affected by the vertical and sagittal surgical movements of the maxilla. There was a moderate correlation between patients’ perception of nasal changes and cephalometric measurements. The subjective evaluation of the nose was similar among patients after surgery, but in the objective assessment, patients found their noses more esthetic.

Highlights

  • Nasal esthetics are improved after orthognathic surgery.

  • Nasal tip changes correlate with surgical maxillary vertical and sagittal movements.

  • The vertical movement of the maxilla affects the vertical position of the nasal tip.

  • Most of the patients were not aware of the changes on their noses after surgery.

  • In objective assessment, patients found their noses more esthetic.

A dentofacial deformity can be defined as any condition that differs from the accepted “normal” appearance of the facial skeleton or causes malocclusion. It may be inherited, developmental, or multifactorial in origin. The treatment of such deformities aims at a functional or esthetic improvement, with the primary approach to treatment being orthognathic surgery. ,

The shape of the nose, as one of the main keystones in facial esthetics, affects appearance substantially, and the shape of the nose may be altered as a result of orthodontic or orthopedic and orthognathic procedures. , In general, the nose may become more evident or camouflaged with any movement of the upper lip, maxilla, mandible, or teeth. Considering the close relationship between the maxilla and the nose, LeFort I osteotomies, which are commonly used in maxillary surgery, have been demonstrated to have the most prominent effect on nose esthetics. Furthermore, although the movement of the mandible has a minimal effect on the nasal parameters, it does change the relationship between the nose and the chin, with the relative prominence of the nose changing because of the advancement of the chin. , ,

The shape of the nose can be improved through a maxillary osteotomy, although the effects may also be negative. A cautious preoperative evaluation of the nose, followed by detailed treatment planning on the basis of these findings, will play a determining role in the success of the surgery. Maxillary advancement surgery is applied in patients with skeletal Class III malocclusion with maxillary retrognathia, and forward movement of the maxilla may result in rotation of the nasal tip and reduction of the nasal protuberance. ,

The self-perception of patients related to their facial appearance and any malformation is highly important. Furthermore, the ability of a person to adapt to a facial deformity can differ, regardless of the degree of severity. It can change significantly from one person to another; some patients may be relatively unaffected, whereas others may experience feelings that significantly affect the quality of their lives.

There have been many studies in the literature evaluating nasal changes, whereas those associated with the self-perception of these changes among patients are scarce.

Our study aimed to evaluate the effects of maxillary surgery on the nose and the correlation between cephalometric measurements and patients’ perception of nasal changes in those with Class III malocclusion.

Material and methods

Patients who underwent orthognathic surgery because of their Class III malocclusion at the Başkent University Hospitals between 2005 and 2017 were included in the study. This study was approved by the University Institutional Review Board and Ethics Committee (project no. D-KA17/07) and supported by the research fund.

Patients with no congenital craniofacial abnormality or syndrome and who have completed their growth development period, with no prior orthognathic or temporomandibular joint surgery, with no additional surgery before or after orthognathic surgery, such as rhinoplasty or augmentation, and those having quality radiographic records were included in the study.

The criteria sought for the cephalometric radiographs were a Frankfort horizontal plane parallel to the floor, teeth at centric occlusion, lips in a resting position, and the presence of calibration rulers through which calibration could be controlled.

On the basis of the specified criteria, 85 patients (49 women and 36 men) from a total of 217 patients who underwent orthognathic surgery were included in the study ( Fig 1 ). The subjects were divided into 2 groups. Group 1 (n = 37) consisted of patients with maxillary advancement and impaction, whereas group 2 (n = 43) consisted of those with maxillary advancement only. In group 1, the impaction of the maxilla was achieved in a parallel manner in 8 of the patients, whereas 29 of the patients received a rotational impaction. The maxilla was impacted more from the posterior than the anterior in 15 patients, whereas in 14 patients, the anterior was impacted more than the posterior. An alar base cinch suture was used in all of the subjects included in the study, but patients with a combined V-Y suture procedure were not included.

Fig 1
Study flow chart.

Lateral cephalometric radiographs were analyzed using Dolphin Imaging software (version 11.5 Premium; Dolphin Imaging and Management Solutions, Chatsworth, Calif), with all measurements made by the same researcher (A.A.), and all radiographs of the same individual digitized consecutively.

A total of 24 cephalometric parameters were analyzed, including 15 soft tissue and 9 skeletal measurements ( Fig 2 ). Parameters were composed of 13 angular measurements, 10 linear, and 1 proportional.

Fig 2
The parameters used in the cephalometric measurements. VR, a vertical reference plane perpendicular to the HR passing through Sella; 1, facial convexity angle (angle formed G′-Subnasale line to Subnasale-Pog’ line); 2, facial profile angle (angle formed between N′-Pronasale and Pronasale-Pog’); 3, nasofacial angle (angle formed between G′-Pog’ and N′-Prn); 4, nasofrontal angle (angle formed between G′-N′ and N′-Prn); 5, nasal tip rotation (angle formed between VR passing over alar curvature point [Ac] and alar curvature-Pronasale [Ac-Prn]); 6, nasal tip projection (the proportional relationship between Ac-Prn and N′-Prn); 7, nasolabial angle; 8, nasal tip inclination (angle formed between N′-Prn and VR); 9, A-HR (perpendicular distance from A-point to HR); 10, A-VR (perpendicular distance from A-point to VR); 11, nasal height (distance between N′ and Sn); 12, Lower nasal height (the vertical distance of Pronazale and Subnazale points to each other); 13, nasal length (distance between N′ and Prn); 14, nasal tip protrusion (distance between Sn and Prn); 15, nasal tip angle (angle formed between N′-Prn and Prn-Sn); HR, a horizontal reference plane angulated 7° clockwise to the Sella-Nasion plane at Sella; 16, Prn-HR (perpendicular distance from Prn to HR); 17, Prn-VR (angle formed between Prn and VR); 18, SNA angle; 19, ANB angle; 20, SNB angle; 21, ANS-HR (perpendicular distance from ANS to HR); 22, ANS-VR (perpendicular distance from ANS to VR); 23, GoGnSN (angle formed between GoGn with SN; 24, Wits appraisal.

Among the 85 patients, 42 patients agreed to fill out the questionnaire ( Fig 3 ), evaluating their own noses on a 7-point Likert scale, which we used to determine patients’ subjective perception (Sbj). The patients were also evaluated esthetically on their silhouettes on the basis of their profile photographs as an objective evaluation (Obj). Care was taken so that the patients did not understand that they were evaluating their own silhouette. After the patients completed the questionnaire, we asked if they had identified that they had evaluated their own silhouette, as we did not want them to know it was their own. One of the patients was excluded, as he noticed that the profile silhouettes were his own. The differences between the sexes were calculated. The correlation between the scores obtained from the questionnaire and the cephalometric data was evaluated.

Fig 3
The nasal esthetic evaluation form.

Statistical analysis

The data were collated and analyzed using SPSS (version 21; SPSS, IBM, Armonk, NY). This study was carried out on the basis of a power of at least 81% with a significance level of 0.05 to achieve an effect size of 0.7. Radiographs were redigitized after 2 weeks by the same clinician (A.A.) to assess intraexaminer reliability. The values for the redigitized films were analyzed using the Dahlberg formula.

The differences between the presurgical and postsurgical data were analyzed using 2 dependent sample t tests, and the correlations between the skeletal maxillary movement and the soft tissue nasal changes were analyzed with Pearson correlation analysis. To evaluate the differences in the soft tissue nasal changes between group 1 (maxillary advancement with impaction) and group 2 (maxillary advancement only), an independent samples t test was used for normally distributed parameters, and parameters that were not normally distributed were evaluated with a Mann-Whitney U test. The proportional relationship between changes in skeletal and nasal soft tissue parameters as a result of the surgical procedure was evaluated using regression analysis.

The correlations between the cephalometric measurements and the esthetic evaluation scores were evaluated with Spearman correlation analysis, whereas Wilcoxon signed rank test was used in the nasal esthetic evaluation questionnaire of the differences between the presurgery (T0) and postsurgery (T1). The same analysis was used to evaluate the differences between the sexes. A P value of <0.05 was considered statistically significant.

Results

The demographic characteristics of the study patients can be summarized as follows: mean age was 22.1 years, and total treatment duration was 28.6 months. Men and women comprised 42.4% (n = 36) and 57.6% (n = 49) of the sample, respectively. Group 1 was composed of 37 (43.5%) patients who underwent impaction in addition to advancement, and group 2 was composed of 48 (56.5%) patients who underwent maxillary advancement only. The Dahlberg error rate was determined to evaluate intraexaminer reliability, and it can thus be accepted that the observer measurements were reliable ( Supplementary Table ).

The mean T0 and T1 parameters used in the evaluation of changes in soft tissues after movements of the maxilla and the statistical significance between T1 and T0 are presented in Table I . According to this, the inclination and rotation of the nasal tip, the nasofacial angle, and the sagittal position of pronasale (Prn-VR) had increased significantly after surgery, whereas nasal tip protrusion, nasofrontal angle, nasal tip projection, and vertical position of pronasale (Prn-HR) values had decreased.

Table I
Evaluation of changes in T0 and T1 − T0 skeletal and soft tissue measurements with 2 dependent samples t tests
T0 T1 − T0
Variables Mean Standard deviation Minimum Maximum 95% Confidence interval Mean Standard deviation Minimum Maximum 95% Confidence interval P v alue
Skeletal parameters
SNA (°) 78.53 4.43 66.00 87.70 77.57 to 79.49 3.94 1.85 −0.30 8.20 3.54 to 4.34 <0.001
SNB (°) 82.12 4.39 69.70 90.60 81.18 to 83.07 −1.99 2.07 −6.10 3.00 −2.44 to −1.54 <0.001
A-HR (mm) 51.00 4.37 39.80 60.40 50.00 to 51.90 −1.21 2.04 −8.70 2.30 −1.65 to −0.76 <0.001
A-VR (mm) 61.64 6.65 49.00 76.10 60.21 to 63.08 3.84 2.21 −3.40 10.60 3.36 to 4.31 <0.001
ANS-HR (mm) 44.86 4.07 35.00 54.90 43.98 to 45.73 −0.65 2.07 −6.70 5.40 −1.10 to −0.21 0.004
ANS-VR (mm) 66.40 7.24 50.90 79.30 64.84 to 67.96 3.60 2.49 −3.90 13.60 3.06 to 4.14 <0.001
ANB (°) −3.58 2.93 −12.20 3.80 −4.21 to −2.95 5.92 2.24 1.10 11.50 5.44 to 6.41 <0.001
Wits (mm) −12.03 4.82 −21.40 13.50 −13.07 to −10.99 8.30 4.53 −17.70 16.60 7.32 to 9.28 <0.001
GoGoSN (°) 38.19 7.10 14.90 53.00 36.66 to 39.73 −1.29 3.94 −11.30 7.70 −2.14 to −0.43 0.003
Soft tissue parameters
Facial convexity angle (°) 174.94 6.73 157.80 190.40 173.49 to 176.40 −7.58 5.68 −38.10 2.80 −8.80, −6.35 <0.001
Facial profile angle (°) 138.89 5.48 127.50 152.10 137.71 to 140.07 −4.05 11.13 −14.00 92.70 −6.45, −1.65 0.001
Nasolabial angle (°) 96.23 13.89 60.30 129.30 93.23 to 99.22 0.01 8.79 −17.70 25.20 −1.88, 1.90 0.979
Nasofacial angle (°) 24.65 3.37 16.30 32.60 23.92 to 25.38 3.23 2.46 −3.30 9.70 2.70 to 3.76 <0.001
Nasofrontal angle (°) 144.98 9.32 120.80 165.70 142.97 to 147.00 −1.84 7.16 −15.60 44.60 −3.39 to −0.30 0.020
Nasal tip rotation (°) 97.22 4.84 84.30 107.40 96.18 to 98.27 2.25 4.24 13.90 13.30 1.33 to 3.16 <0.001
Nasal tip protrusion (mm) 20.01 2.28 12.60 26.50 19.52 to 20.50 −0.44 1.44 −4.00 3.60 −0.76 to −0.13 0.005
Nasal tip projection 0.59 0.04 0.49 0.72 0.58 to 0.60 −0.02 0.03 −0.14 0.07 −0.03 to −0.01 <0.001
Nasal tip angle (°) 80.34 9.73 58.00 104.40 78.24 to 82.43 −0.16 4.88 −17.80 14.40 −1.22 to 0.88 0.75
Nasal tip inclination (°) 27.77 4.36 15.60 37.70 26.83 to 28.71 2.20 3.50 −6.50 11.20 1.45 to 2.96 <0.001
Nasal length (mm) 51.23 4.66 41.70 65.80 50.22 to 52.23 −0.31 2.35 −7.90 4.70 −0.82 to 0.19 0.219
Nasal height (mm) 56.48 4.37 48.30 68.00 55.53 to 57.42 −0.40 2.55 −8.30 8.50 −0.95 to 0.15 0.153
Lower nasal height (mm) 11.75 3.04 7.60 32.20 11.09 to 12.40 −0.15 2.68 −19.40 5.10 −0.73 to 0.42 0.587
Prn-HR (mm) 40.59 4.88 27.00 50.10 39.54 to 41.65 −1.38 1.90 −6.10 4.90 −1.79 to −0.97 <0.001
Prn-VR (mm) 95.14 8.09 80.40 113.40 93.40 to 96.89 1.39 2.57 −11.90 10.20 0.83 to 1.95 <0.001

P < 0.05.

The correlation of the vertical and anteroposterior surgical movement of the maxilla with the nasal parameters was evaluated and presented in Table II . Maxillary advancement and changes in A-VR have been observed to correlate moderately with Prn-VR. Similarly, ANS-HR and Prn-HR were found to be moderately correlated ( P <0.05).

Table II
Evaluation of the relationship between skeletal maxillary movements and nasal soft tissue changes by Pearson correlation analysis
SNA ANB Wits appraisal GoGnSN A-HR A-VR ANS-HR ANS-VR
Variables r P value r P value r P value r P value r P value r P value r P value r P value
Nasal tip inclination 0.237 0.029 −0.041 0.710 −0.082 0.455 −0.169 0.122 −0.188 0.084 0.188 0.086 −0.192 0.078 0.115 0.296
Nasal height −0.046 0.675 0.143 0.192 0.017 0.879 0.191 0.079 0.309 0.004 0.214 0.050 0.260 0.016 0.264 0.015
Nasal length −0.055 0.617 0.046 0.679 −0.066 0.549 0.113 0.301 0.237 0.029 0.249 0.022 0.156 0.154 0.269 0.013
Nasal tip protrusion −0.060 0.586 −0.056 0.613 −0.053 0.628 0.036 0.743 0.186 0.087 0.163 0.136 0.201 0.065 0.261 0.016
Facial convexity angle −0.086 0.436 −0.528 <0.001 −0.241 0.026 −0.355 0.001 −0.065 0.552 0.031 0.781 −0.105 0.337 0.073 0.505
Facial profile angle 0.015 0.891 −0.221 0.042 −0.116 0.289 −0.062 0.574 0.064 0.561 −0.044 0.690 0.043 0.695 −0.013 0.909
Nasofacial angle 0.057 0.604 0.509 <0.001 0.122 0.267 0.368 0.001 0.133 0.225 0.080 0.466 0.100 0.361 −0.012 0.912
Nasofrontal angle 0.040 0.713 0.103 0.349 0.121 0.271 0.155 0.158 −0.008 0.942 −0.067 0.544 −0.002 0.988 −0.064 0.562
Nasolabial angle 0.038 0.732 0.294 0.006 0.067 0.544 0.180 0.099 0.303 0.005 −0.081 0.463 0.133 0.225 0.071 0.521
Nasal tip rotation 0.112 0.308 0.106 0.333 −0.069 0.533 0.226 0.038 0.304 0.005 0.405 <0.001 0.309 0.004 0.466 <0.001
Nasal tip projection 0.025 0.820 0.074 0.503 0.035 0.750 −0.052 0.635 −0.065 0.555 0.081 0.460 −0.101 0.358 0.038 0.728
Nasal tip angle 0.165 0.132 0.372 <0.001 0.232 0.032 0.222 0.042 0.201 0.065 0.002 0.982 0.195 0.074 0.082 0.453
Lower nasal height −0.021 0.846 0.002 0.989 −0.034 0.760 0.013 0.904 0.102 0.355 0.138 0.207 0.195 0.074 0.169 0.122
Prn-HR −0.469 <0.001 −0.083 0.452 −0.018 0.867 0.333 0.002 0.411 <0.001 −0.095 0.385 0.543 <0.001 −0.078 0.476
Prn-VR 0.066 0.551 −0.051 0.640 0.188 0.085 0.112 0.308 0.210 0.054 0.508 <0.001 0.200 0.067 0.382 <0.001
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Jun 12, 2021 | Posted by in Orthodontics | Comments Off on Correlation between cephalometric nasal changes and patients’ perception after orthognathic surgery
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