Evaluation of the Nasolabial Angle in Orthodontic Diagnosis: A Systematic Review

Reconsidering the role of nasolabial angle in premolar extraction decision-making: A case-series study

OBJECTIVES

To evaluate the impact of changes in upper incisor inclination and position on the alteration of the nasolabial angle (NLA) in a series of cases involving the extraction of four first premolars.

MATERIALS AND METHODS

The study included 41 patients who underwent orthodontic treatment with premolar extractions. The patients were divided into two groups based on their pretreatment NLA values: Group 1 (NLA ≤ 100°) and Group 2 (NLA > 100°). Measurements of NLA, U1.NA and U1-NA were obtained before and after treatment and U1-Ls pretreatment measure was registered. Statistical analyses were performed to compare the differences in NLA, U1.NA and U1-NA between the two groups and to evaluate the influence of these variables added to U1-Ls (T1) on NLA changes.

RESULTS

The results showed that Group 1 exhibited significant changes in NLA, while Group 2 did not. However, both groups showed significant changes in U1.NA and U1-NA. In Group 1, 80% of the individuals presented an increase in NLA and 20% no changes. In Group 2, 10% presented a decrease, 57% no changes and 33% an increase in NLA values. Multiple linear regression analysis indicated that the group factor had a statistically significant influence on NLA variation. Additionally, in Group 2, a negative correlation was observed between changes in U1.NA and NLA.

CONCLUSIONS

The findings suggest that individuals with higher pretreatment NLA values tend to maintain their NLA values even after the correction of upper incisor inclination.

Süreyya-Dani technique, a new technique to address notching of soft triangle and opening external nasal valve

Introduction

While different methods are employed for fixing narrowed nasal valves and preventing the notching of soft triangles, this study aims to demonstrate the effectiveness of a new technique called Süreyya-Dani Technique.

Methods

This prospective study composed 100 patients who underwent rhinoplasty using the Süreyya-Dani technique. All patients presented with either notching of the soft triangle and/or external nasal valve dysfunction. Patients with the absence of soft triangle notching and external nasal valve dysfunction were excluded from this study. Facial analysis was conducted for all patients to identify any asymmetry in the face, and all nasal defects were identified. Descriptive statistics were calculated for different variables. Analytical statistics, namely Chi-Square test, was conducted with a significance level set at P < 0.05.

Results

In the current study, 100 patients were involved, out of which 63 (63%) were female and 37 (37%) were male. The participants' ages ranged from 18 to 46 years, with a mean age of 30 years. various chief complaints were found among patients, with the majority 37(37%) expressing cosmetic concerns. A statistically significant difference was found for the association of nasal tip defects with genders, intraoperative findings, and chef complaints, and the association between the degree of external valve insufficiency and crural weakness (P-value < 0.05).

Conclusion

Despite many techniques that have been put forward to fix narrowed nasal valves and prevent notching of the soft triangle, the Süreyya-Dani Technique could work to prevent its occurrence successfully.

Novel Parameter in Pre-Surgical Orthodontic Preparation: A Retrospective Study on the Role of the Upper Incisor Position and a Morphological Evaluation of the Anterior Nasal Spine

The position and inclination of the incisors play a crucial role in achieving optimal outcomes in orthodontic and orthognathic surgical treatment, given their impact on facial aesthetics. Background/objectives: Due to numerous distorting factors that affect the reliability of the ANB angle, the aim of the present work is to evaluate a more constant parameter over time, the anterior nasal spine (ANS), and explore whether aligning the incisal margin of the upper incisors with the anterior nasal spine could be a reliable indicator for achieving appropriate labial support in pre-surgical orthodontic preparation. Methods: From a pool of 500 cone beam computed tomography (CBCT) scans, 50 CBCT examinations displaying a Class 1 skeletal pattern (ANB = 2° ± 2°) with an intermediate (3.2-4 mm) or mixed (4-6 mm) sagittal maxillary position (MX), as determined by the 3D multiplanar total face approach (TFA), were selected and compared with CBCT examinations randomly chosen from the initial pool. Moreover, 12 landmarks were identified, and measurements were automatically obtained, using software, and recorded. Mean and standard deviation values were calculated for each sample. A comparison was made between the two samples, aligning the results with the morphological analysis of the anterior nasal spine and the sagittal position of the upper maxilla. Results: In Class 1 subjects, the distance between the incisal margin and the plane passed in relation to the anterior nasal spine should range between -1 mm and 1 mm, aligned with or slightly ahead of the anterior nasal spine or slightly ahead of this limit. Conclusions: The anterior nasal spine can serve as a reliable reference point for planning the position of the upper incisors, with excessive proclination or retroclination from this reference point deemed unacceptable.

Correlation between Nasolabial Angle and Maxillary Incisors Inclination in 18-25-Year-Old Chhattisgarh Population Using Pre- and Post-Treatment Lateral Cephalograms: A Retrospective Study

INTRODUCTION

One of the primary objectives of orthodontic treatment has been the enhancement of facial aesthetics. To obtain the perfect facial profile with aesthetic balance, knowledge of facial anatomy is essential. The diagnosis and treatment planning of orthodontic patients depend greatly on the examination of the soft tissue profile. Since the nasolabial angle is significantly affected by the inclination of the upper incisors, it is a frequently employed soft tissue parameter in orthodontic diagnosis.

AIM

The study aimed to find out the correlation between the nasolabial angles with maxillary incisor inclination.

MATERIALS AND METHODS

In this retrospective study, 120 lateral cephalograms of orthodontic patients including males and females were traced. Their nasolabial angle and maxillary incisor inclination were calculated before and after orthodontic treatment.

RESULT

The mean of pre- and post-treatment nasolabial angle was found to be 91.43° ± 14.008 and 97.93° ± 14.194, respectively. The mean of pre- and post-treatment incisor inclination was found to be 32.59° ± 7.290 and 23.98° ± 6.851, respectively. The gender-wise Pearson's correlation (r) of nasolabial angle with incisor inclination for male and female was found to be -0.464 with a P value of 0.164 and -0.305 with a P value of 0.118, respectively. Overall Pearson's correlation of nasolabial angle with incisor inclination was found to be -0.040 with a P value of 0.384.

CONCLUSION

There is an insignificant negative correlation between nasolabial angle and incisor inclination in the Chhattisgarh population as well as among the two genders.

Relationship between Selected Cephalometric Parameters, Nasolabial Angle and Its Components in Adolescent Females

Nasolabial angle is commonly used to assess the soft tissue profile of the subnasal region. The aim of this retrospective study was to evaluate the relationship between the nasolabial angle, the inclination of the lower border of the nose and upper lip, upper incisor inclination and upper lip thickness. A sample of 142 female adolescents aged 13-18 years was chosen. A modified cephalometric analysis was performed with the nasolabial angle, and its components were traced according to Fitzgerald's method. All analysed parameters showed a statistically significant correlation with the nasolabial angle (NLA). The highest correlation was found for the labial (L/FH) and nasal (N/FH) components of the nasolabial angle, respectively. Upper incisor inclinations (1+:SN, U1FA) and upper lip thickness (ULT) had a stronger correlation with L/FH than NLA, but no correlation was found between these parameters and N/FH. Upper lip thickness did not influence the relationship between incisor inclination and NLA or L/FH. The position of the upper incisors and upper lip thickness influence the nasolabial angle indirectly through its labial component (L/FH). Therefore, it seems purposeful to assess the nasolabial angle as a sum of two independent angles, of which only one (L/FH) can be influenced by orthodontic treatment.

Novel Approach for Midface Depression

Background:

Although Le Fort type II, prosthesis detainment, and orthodontic treatment are considered for the management of midface retraction, they may be limited by their high cost, infection risk, and excessive amount of tooth movement. Therefore, the Point A-Koji method was devised as a novel treatment in patients with midface retraction.

Methods:

This is a case report of a 26-year-old woman who presented with a feeling of depressed midface and protrusion of the mouth. Preoperatively, the position of the lip and line connecting the nasal apex and mental muscles (E-line) were normal, but the subnasale was located posteriorly. The patient had a narrow nasolabial angle of 74 degrees and the subnasale-Pog’ to the upper lip of 6.5 mm. After insertion of a metallic-plate implant under the periosteum, the plate was screwed and fixed to the bone. The Point A-Koji method was used for treatment in this patient. This is characterized by the A-point anterior migration technique in which the periosteum of hard tissue A-point circumferential attachment was shifted anteriorly, thereby preventing the return of soft tissue.

Results:

The following changes with respect to preoperative findings were noted 5 months postsurgery: facial convexity from 3.3 degrees to 7.6 degrees; nasolabial angle from 74 degrees to 90.2 degrees; true horizontal line from 50 degrees to 73 degrees; and subnasale-Pog’ to the upper lip from 6.5 mm to 4.7 mm. This resulted in an improved midface retraction.

Conclusion:

The Point A-Koji method may be an ideal method to improve the midface retraction in patients.