A cone-beam computed tomography evaluation of facial asymmetry in unilateral cleft lip and palate individuals

Mandibular condyle volumes are associated with facial asymmetry in patients with cleft lip and palate: A retrospective cohort study

This study compares condylar volumetric asymmetry and facial asymmetry in patients with cleft lip and/or palate (CLP) and controls. The mandibular condyle is important to facial growth, but its role in facial asymmetry for those with CLP has not been described. Condylar volumes and mandibular asymmetry were retrospectively calculated using Mimics Version 23.0 (Materialise, Leuven, Belgium) from patients with CLP undergoing computed tomography (CT) imaging and a cohort of controls. A total of 101 participants, 60 with CLP and 41 controls, had mean condylar volumetric asymmetry of 16.4 ± 17.4 % (CLP) and 6.0 ± 4.0 % (controls) (p = 0.0002). Patients with CLP who had clinically significant chin deviation (>4 mm) had more asymmetric condyles than those without significant chin deviation (p = 0.003). The chin deviated toward the smaller condyle in patients with facial asymmetry more often than in patients without facial asymmetry (81 % vs. 62 %, p = 0.033). While controls had some degree of condylar asymmetry, it tended to be milder and not associated with facial asymmetry. There is a greater degree of condylar volumetric asymmetry in patients with CLP compared to individuals in the general population. Clinically significant facial asymmetry in CLP is associated with a higher degree of condylar asymmetry, with the facial midline deviating toward the smaller condyle.

Effectiveness of Early Intervention with Palatal Expansion Versus Late Orthodontic Treatment for Correcting Maxillary Crowding

Background

Maxillary crowding is a common orthodontic issue that can impact a patient's oral health and overall well-being. The timing of orthodontic treatment plays a crucial role in achieving optimal results.

Materials and Methods

Thirty patients who received early intervention with palatal expansion (Group A) and 30 patients who underwent late orthodontic treatment (Group B) were included in this study. The age range for Group A was 8-10 years, while Group B had an age range of 16-18 years. Pretreatment and posttreatment records, including dental models and cephalometric radiographs, were analyzed to assess the effectiveness of the respective treatments.

Results

In Group A, the mean duration of treatment was 12 months, and the maxillary crowding was corrected by an average of 4.5 mm. In Group B, the mean treatment duration was 24 months, and maxillary crowding was corrected by an average of 3.2 mm. The early intervention group (Group A) exhibited a statistically significant reduction in treatment duration and greater correction of maxillary crowding compared to the late orthodontic treatment group (Group B) (P < 0.05).

Conclusion

Early intervention with palatal expansion is an effective approach for correcting maxillary crowding, leading to shorter treatment duration and greater improvement compared to late orthodontic treatment.

Mandibular Radiomorphometric Characteristics of Individuals with Bilateral or Unilateral Cleft Lip and Palate

OBJECTIVE

This study aimed to investigate and compare the mandibular radiomorphometric characteristics of patients with unilateral or bilateral cleft lip and palate (CLP) with those of individuals without CLP and to determine whether there was a difference.

DESIGN

Retrospective cohort study.

SETTING

Orthodontic Department in Faculty of Dentistry.

PATIENTS AND INTERVENTIONS

Mandibular cortical bone thickness was measured on high-quality panoramic radiographs taken from 46 patients with unilateral or bilateral CLP aged 13-15 years and 21 control patients.

MAIN OUTCOME MEASURES

Three radiomorphometric indices [antegonial index (AI), mental index (MI), and panoramic mandibular index (PMI)] were measured bilaterally. AutoCAD software was used for MI, PMI, and AI measurements.

RESULTS

Left MI values were significantly lower in individuals with unilateral cleft lip and palate (UCLP; 0.029 ± 0.04) than in individuals with bilateral cleft lip and palate (BCLP; 0.033 ± 0.07). In addition, right MI values of individuals with right UCLP (0.26 ± 0.06) were significantly lower than those of individuals with left UCLP (0.34 ± 0.06) or BCLP (0.32 ± 0.08). No difference was observed between individuals with BCLP and left UCLP. These values did not differ between groups.

CONCLUSIONS

Antegonial index and PMI values did not differ between individuals with different types of CLP or when compared with control patients. In patients with UCLP, cortical bone thickness was found to be reduced on the cleft side compared to the intact side. Patients with UCLP with a right-sided cleft had a more substantial decrease in cortical bone thickness.

Evaluation of the posterior superior alveolar artery location and diameter with a newly defined stable plane

The aim of this study was to analyse the vertical location of the posterior superior alveolar artery (PSAA) using a reliable new reference plane regardless of tooth and alveolar bone, and to measure the diameter in each posterior tooth region, which is of relevance to lateral sinus floor elevation surgery. A total of 270 sinuses in 139 patients were examined in this study. The A-plane was defined by A-point and the bilateral jugal points on reconstructed three-dimensional images. The distance from the PSAA to the defined plane was measured in four regions: first premolar (P1), second premolar (P2), first molar (M1), and second molar (M2). The average distance of the PSAA above the plane in the P1, P2, M1, and M2 regions was determined to be 10.24mm, 7.35mm, 5.47mm, and 7.23mm, respectively. The PSAA was found to run above the plane in 97.4% of sinuses, below the plane in 1.1%, and on the plane in 1.5%. In conclusion, the new plane is useful for intraoperative location of the PSAA. According to the study findings, the area below the reference plane can be considered safe for lateral approach sinus surgery in terms of preserving the integrity of the PSAA.

Growth patterns of the nasolabial region following unilateral cleft lip primary repair

Surgical correction is the optimal way of repairing a congenital cleft lip. Patients with this condition often undergo initial surgical treatment at an early age and achieve an acceptable outcome. However, their levels of satisfaction will decrease in later stages of life as facial growth and development will inevitably cause changes in long-term outcomes, especially in the nasolabial region. Therefore, it is important for surgeons to understand nasolabial development after primary treatment and tailor their surgical techniques appropriately. This review focuses on the growth patterns of the nasolabial region after primary repair, so as to provide references for operative strategy.

Facial Asymmetry Detected with 3D Methods in Orthodontics: A Systematic Review

Background:

Historically, the development of two-dimensional (2D) imaging techniquesforerun that of three-dimensional (3D) ones. Some 2D methods are still considered valid and effective to diagnose facial asymmetry but 3D techniques may provide more precise and accurate measurements.

Objective:

The aim of this work is to analyze the accuracy and reliability of the imaging techniques available for the diagnosis of facial asymmetry in orthodontics and find the most reliable.

Methods:

A search strategy was implemented using PubMed (National Library of Medicine, NCBI).

Results:

A total of 3201 papers were identified in electronic searches. 90 articles, available in full text, were included in the qualitative synthesis consisting of 8 reviews on the diagnosis of facial asymmetry, 22 in vivo and in vitro studies on 2D methods and 60 in vivo and in vitro studies on 3D methods to quantify the asymmetry.

Conclusion:

2D techniques include X-ray techniques such as posterior-anterior cephalogram, which still represents the first level exam in the diagnosis of facial asymmetry. 3D techniques represent the second level exam in the diagnosis of facial asymmetry. The most current used techniques are CBCT, stereophotogrammetry, laser scanning, 3D optical sensors and contact digitization. The comparison between bilateral parameters (linear distances, angles, areas, volumes and contours) and the calculation of an asymmetry index represent the best choices for clinicians who use CBCT. The creation of a color-coded distance map seems to represent the most accurate, reliable and validated methods for clinicians who use stereophotogrammetry, laser scanning and 3D optical sensors.

Assessment of the asymmetry of the lower jaw, face, and palate in patients with unilateral cleft lip and palate

Background:

This study aimed to assess the asymmetry of the lower jaw, face, and palate in patients with unilateral cleft lip and palate (UCLP) using photography, cone-beam computed tomography (CBCT), and digitized three-dimensional casts.

Methods:

This case–control study was conducted on photographic, CBCT, and digital cast records of 14 UCLP patients and 24 healthy controls between 10 and 16 years. Totally, 65 variables were measured on photographs, CBCT scans, and on digitized casts. Measurements were compared between the two groups and within each group between the two sides. For easier measurement, in patients who had right side CLP, the cleft was transferred to the left side and in subjects without cleft, mild chin deviation was transferred to the left side.

Results:

The anteroposterior dimensions of the two condyles in the UCLP group were greater than those in the control group, while the mediolateral dimensions of the left condyle and ramus height, mandibular body length, and total length of the mandible in the control group were greater than those in the UCLP group. Right ocular, nasal, and angular variables were greater in the UCLP group. Other variables except for the palatal width from the right canine to midline were greater in the control group.

Conclusion:

Our findings highlighted the presence of asymmetry in the nasal and palatal areas in patients with UCLP while these patients had no significant difference with healthy controls in the relationship of condyles with the temporomandibular fossa.

Nasal asymmetry changes during growth and development in 6- to 12-year-old children with repaired unilateral cleft lip and palate: A 3D computed tomography analysis

Repaired unilateral cleft lip and palate (UCLP) is often accompanied by the deformity and asymmetry of the nasal region. Three‐dimensional analysis was performed to investigate the relationship between nasal soft‐ and hard‐tissue asymmetries, as well as the changes in nasal asymmetry with age, among children with repaired UCLP (age: 6–12 years). Forty‐seven patients were included in this study. Their computed tomography records were retrieved for analysis of the 3D asymmetry of 10 landmarks of the nasal soft and hard tissues. We observed that asymmetry was more severe in nasal hard tissues than in soft tissues, particularly in the sagittal dimension. Compared with patients aged 6–9 years old, patients aged 10 to 12 years old had significantly increased vertical asymmetry at the base of the alar groove (Gbase, p = 0.027) and the lateral point of the piriform aperture (LPA), (p < 0.001). The correlation between the LPA and the alar region was weak to moderate (r = 0.290 to 0.488). In conclusion, we found no evidence of growth and development in nasal hard‐tissue asymmetry among 6‐ to 12‐year‐old children with repaired UCLP, except for the vertical dimension. Nasal soft tissue exhibited a more preferable symmetry than hard tissue, and this could be attributed to the compensatory growth of nasal soft tissue, particularly in the vertical and sagittal dimensions. The weak to moderate correlations between nasal soft‐tissue asymmetry and hard‐tissue asymmetry were observed in the three dimensions. Surgeons should consider these factors when repositioning the nasal alar and controlling the size of the nostrils.

3D morphometric quantification of maxillae and defects for patients with unilateral cleft palate via deep learning-based CBCT image auto-segmentation

OBJECTIVE

This study aimed to quantify the 3D asymmetry of the maxilla in patients with unilateral cleft lip and palate (UCP) and investigate the defect factors responsible for the variability of the maxilla on the cleft side using a deep-learning-based CBCT image segmentation protocol.

SETTING AND SAMPLE POPULATION

Cone beam computed tomography (CBCT) images of 60 patients with UCP were acquired. The samples in this study consisted of 39 males and 21 females, with a mean age of 11.52 years (SD = 3.27 years; range of 8-18 years).

MATERIALS AND METHODS

The deep-learning-based protocol was used to segment the maxilla and defect initially, followed by manual refinement. Paired t-tests were performed to characterize the maxillary asymmetry. A multiple linear regression was carried out to investigate the relationship between the defect parameters and those of the cleft side of the maxilla.

RESULTS

The cleft side of the maxilla demonstrated a significant decrease in maxillary volume and length as well as alveolar length, anterior width, posterior width, anterior height and posterior height. A significant increase in maxillary anterior width was demonstrated on the cleft side of the maxilla. There was a close relationship between the defect parameters and those of the cleft side of the maxilla.

CONCLUSIONS

Based on the 3D volumetric segmentations, significant hypoplasia of the maxilla on the cleft side existed in the pyriform aperture and alveolar crest area near the defect. The defect structures appeared to contribute to the variability of the maxilla on the cleft side.

Vertical Facial Skeletal Asymmetry and Occlusal Cant Relationship in Patients With Unilateral Cleft Lip and Palate

OBJECTIVE

To evaluate the maxillary and mandibular vertical skeletal asymmetries, and the correlation between these asymmetries and occlusal cant in patients with unilateral cleft lip-palate (UCLP).

METHODS

Anteroposterior radiographs of 25 patients with UCLP (UCLP group, mean age: 20.98 ± 4.88 years) and 25 subjects without cleft (control group, mean age: 19 ± 2.86 years) were included. Independent samples t test, Mann-Whitney U test and Pearson correlation analysis were performed based on linear and angular measurements.

RESULTS

Lower facial horizontal asymmetry did not show statistically significant difference between the UCLP and control groups. However, vertical asymmetry of (a) the lateral cranial base (P = .014), (b) the nasomaxillary region (P < .001), (c) the maxillary dentoalveolus (P = .001), and (d) the lower face (P = .038) were all found to be significantly greater in UCLP group. The occlusal cant angle was also significantly greater in patients with UCLP compared to the controls (P = .016). While the occlusal cant angle was found to be correlated with the vertical asymmetry of the occlusal cant (r = 0.931, P < .001), maxillary cant angle was found to be correlated with the vertical asymmetry of the maxillary dentoalveolus (r = 0.655, P < .001).

CONCLUSIONS

There was no correlation between the occlusal cant and the vertical and horizontal skeletal asymmetries. Vertical asymmetries of the lower face and the medial cranial base were negatively correlated with the horizontal lower facial asymmetry.

CBCT in orthodontics: a systematic review on justification of CBCT in a paediatric population prior to orthodontic treatment

BACKGROUND

Taking into account radiation doses, safety, and protection, we highlighted the features in which cone-beam computed tomography (CBCT) can offer an advantage compared to the conventional two-dimensional imaging in paediatric dentistry before orthodontic treatment.

OBJECTIVE

The aim of this article was to conduct a systematic review to assess the diagnostic efficacy of CBCT in the paediatric population at a pre-orthodontic phase.

SEARCH METHODS

MEDLINE via PubMed was searched to identify all peer-reviewed articles potentially relevant to the review until 1 July 2018. Relevant publications were selected by two reviewers independently.

SELECTION CRITERIA

The literature selection for this systematic review was carried out according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement and was based on predetermined inclusion criteria.

DATA COLLECTION AND ANALYSIS

Data were collected on overall study characteristics and examination characteristics of the selected studies. Methodological quality of the selected studies was evaluated. Original studies were assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS) tool. Thereafter, levels of evidence were obtained according to Grading of Recommendations Assessment, Development and Evaluation criteria.

RESULTS

As a result of the QUADAS assessment, a total of 37 articles were included in the protocol. Following a proper protocol, CBCT was regarded as a reliable tool for assessment and management of impacted canine and root fracture. It provided a better evaluation of normal and pathological condylar shape and volume. CBCT was a superior choice for pre-surgical diagnostic applications in cleft lip and/or palate over a medical computed tomography based on its lower radiation exposure, shorter investigation time, and low purchase costs.

CONCLUSIONS

CBCT is justified only in those cases where conventional radiography fails to provide a correct diagnosis of pathology. Therefore, it cannot be regarded as a standard method of diagnosis. CBCT imaging may also be justified when it positively affects treatment options or provides treatment optimization.

REGISTRATION

None.

CONFLICT OF INTEREST

None to declare.

Three-Dimensional Analysis of Craniofacial Structures of Individuals With Nonsyndromic Unilateral Complete Cleft Lip and Palate

ABSTRACT

Cleft lip and palate (CLP) is one of the most common congenital deformities. Primary surgeries at an early age result in scar formation, which may impede the growth of craniofacial structures of the maxilla. Orthodontist's role in the management of individuals with CLP is important and starts from the time of birth. The knowledge of craniofacial structures in individuals with a cleft is essential for treatment planning. The purpose of this study was to analyze and compare craniofacial structures of cleft and noncleft side of individuals with non-syndromic unilateral complete cleft lip and palate (NSUCCLP) using cone-beam computed tomography (CBCT). CBCT scans of individuals with NSUCCLP (n = 42) were retrieved from the databases of two cleft centers, which followed the same protocols for timing and type of primary surgeries and secondary alveolar bone grafting (SABG). DICOM files of CBCT scans were integrated into Dolphin 3D software, and analysis was carried out in multiplanar views. The craniofacial structures of individuals with NSUCCLP were analyzed using fourteen parameters. Measurements were also recorded between the cleft and noncleft sides for comparison. The volume of the maxilla was generated by isolating it from adjacent structures on a 3D reconstructed model. MAWC, MAWPM1, MAWPM2, MAWM1, and MV of the cleft side was less than noncleft side (P < 0.05). MHP @ N Aper is less on the noncleft side (P < 0.05). There is an asymmetry of structures around the dentoalveolar and nasal region; however, asymmetries were not affected at deeper structures of the craniofacial region of individuals with NSUCCLP.

Three-dimensional evaluation of maxillary sinus and maxilla for adolescent patients with unilateral cleft lip and palate using cone-beam computed tomography

BACKGROUND AND OBJECTIVE

Maxillary sinus disease is frequently observed in patients with unilateral cleft lip and palate (UCLP). The anatomical variations of maxillary sinus and maxilla may play a role in the high incidence of sinusitis. The aims of this study were to evaluate and compare the three-dimensional (3D) structural features of maxillary sinus and maxilla in UCLP adolescent patients between the defect and non-defect sides, and investigate the morphological relationship between the maxillary sinus and maxilla on the defect side by using cone-beam computed tomography (CBCT).

METHODS

CBCT images were acquired from 42 UCLP adolescent patients. Maxillary sinus and maxilla on the defect and non-defect sides were segmented respectively and assessed three dimensionally, and the comparison was performed by paired t-test. A multiple linear regression was conducted to investigate the morphological relationship between the maxillary sinus and maxilla on the defect side.

RESULTS

No statistically significant difference was observed in any parameter of the maxillary sinus between the defect and non-defect sides (P > 0.05). Significant differences were observed in the length, anterior width, anterior height, and volume of the maxilla between the defect side and non-defect sides (P < 0.05). The parameters of maxillary sinus were significant related to the posterior width and height of maxilla on the defect side.

CONCLUSION

Adolescent patients with UCLP present similar 3D structural features of the maxillary sinus on both sides. Significant differences of the maxilla between the defect and non-defect sides were displayed in the area adjacent to the defect but not showed in the posterior portion of maxilla. Certain structures of the posterior portion of maxilla contribute to the variability of maxillary sinus.

Outcome of facial contour asymmetry after conventional two-dimensional versus computer-assisted three-dimensional planning in cleft orthognathic surgery

Computer-assisted 3D planning has overcome the limitations of conventional 2D planning-guided orthognathic surgery (OGS), but difference for facial contour asymmetry outcome has not been verified to date. This comparative study assessed the facial contour asymmetry outcome of consecutive patients with unilateral cleft lip and palate who underwent 2D planning (n = 37)- or 3D simulation (n = 38)-guided OGS treatment for correction of maxillary hypoplasia and skeletal Class III malocclusion between 2010 and 2018. Normal age-, gender-, and ethnicity-matched individuals (n = 60) were enrolled for comparative analyses. 2D (n = 60, with 30 images for each group) and 3D (n = 43, with 18 and 25 images for 2D planning and 3D simulation groups, respectively) photogrammetric-based facial contour asymmetry-related measurements were collected from patients and normal individuals. The facial asymmetry was further verified by using subjective perception of a panel composed of 6 blinded raters. On average, the facial contour asymmetry was significantly (all p < 0.05) reduced after 3D virtual surgery planning for all tested parameters, with no significant differences between post-OGS 3D simulation-related values and normal individuals. No significant differences were observed for pre- and post-OGS values in conventional 2D planning-based treatment, with significant (all p < 0.05) differences for all normal individuals-related comparisons. This study suggests that 3D planning presents superior facial contour asymmetry outcome than 2D planning.

Evaluation of the Effectiveness of an Alar Transfixion Suture for the Correction of a Vestibular Web and Alar-Facial Groove: A Photogrammetric Analysis

BACKGROUND

Alar transfixion sutures are commonly used for vestibular web correction. The purpose of this study was to evaluate the long-term results of the use of alar transfixion sutures in patients with a unilateral cleft lip nasal deformity using photogrammetric analysis.

METHODS

The study included 42 patients who were divided into child and adult groups. A total of 4 measurement items were evaluated from a basal view by photogrammetry using standardized clinical photographic techniques preoperatively, immediately postoperatively, 3 months postoperatively, and 6 months postoperatively.

RESULTS

When the preoperative and last postoperative values were compared, no significant changes in any measurement items were noted in the adult group. In the child group, the proportional index (the ratio of the cleft side to the noncleft side) of the alar slope line inclination was significantly increased, but other measurement items showed no significant change. When the measurement items were compared between time points, no significant changes in any measurement items were noted in the adult group. In the child group, the proportional indexes of the alar length, the width between the subnasale and the alare, and the webbing degree were significantly decreased immediately postoperatively compared with the preoperative values. However, these significant changes were diminished at 3 months postoperatively. The proportional index of the alar slope line inclination was significantly increased at 3 months postoperatively compared with the preoperative value, but the significant change was diminished at 6 months postoperatively.

CONCLUSIONS

The alar transfixion suture procedure is not effective for correcting a vestibular web and alar-facial groove.

Hard- and soft-tissue symmetry comparison in patients with Class III malocclusion

OBJECTIVE

Our aim was to describe hard- and soft-tissue asymmetry in people who have a skeletal Class III malocclusion, and to compare with those without asymmetry. We also performed a regional analysis of a possible correlation between facial soft- and hard-tissue asymmetries.

METHODS

This retrospective study was performed with the use of the computed tomographic scans of 60 subjects. The skeletal Class III subjects were categorized into 2 subgroups: soft-tissue menton deviation ≤4 mm (n = 20) versus >4 mm (n = 20). The Class III groups were compared with a Class I symmetry group (n = 20). Hard and soft tissues were segmented into different morphologic areas and deviation calculated. Pearson correlation coefficients were obtained, and 1-way analysis of variance was conducted for statistical analysis.

RESULTS

The highest deviation in the hard tissues of the Class III asymmetry group was in the corpus region (5.55 ± 3.05 mm), with the second highest in the angulus region (4.70 ± 2.43 mm). The highest average deviation in the soft tissues was seen in the lower cheek (7.04 ± 3.46 mm). In the different study groups, the amounts of asymmetry measured in anatomic structures on the mandible were found to be highly correlated between neighboring structures.

CONCLUSIONS

Clinically and statistically significant differences were found in the anatomic regions located in the middle and lower thirds of the face. There was a medium or high correlation between condyle, coronoid process, ramus, and angulus regions. A low level of correlation was observed between middle face and mandibular asymmetries in hard-tissue upper cheek and lower cheek regions were correlated with different mandibular regions.

Cleft Skeletal Asymmetry: Asymmetry Index, Classification and Application

OBJECTIVE

To quantitatively measure the extent of 3D asymmetry of the facial skeleton in patients with unilateral cleft lip and palate (UCLP) using an asymmetry index (AI) approach, and to illustrate the applicability of the index in guiding and measuring treatment outcome.

METHOD

Two groups of subjects between the ages of 15 and 20 who had archived CBCT scan were included in this study. Twenty-five patients with complete UCLP were compared with 50 age-matched noncleft subjects. The CBCT scans were segmented and landmarked for 3D anthropometric analysis. An AI was calculated as a quantitative measure of the extent of facial skeletal asymmetry.

RESULTS

For the control group, the AI ranged from 0.72 ± 0.47 at A point to 4.77 ± 1.59 at Gonion. The degree of asymmetry increased with the increasing laterality of the landmark from the midsagittal plane. In the UCLP group, the values of AI significantly increased compared to the control group at nearly all measured landmarks. The extent of the asymmetry to involve the upper, middle, and lower facial skeleton varied widely with the individual patient with UCLP.

CONCLUSION

The asymmetry index is capable of capturing the 3D facial asymmetry of subjects with UCLP and as a basis for classification of the extent of the asymmetry. We found the index to be applicable in surgical planning and in measuring the outcome in improving the symmetry in patients who have undergone orthognathic surgery.

Interferon regulatory factor 6 variants affect nasolabial morphology in East Asian populations

OBJECTIVE

The interferon regulatory factor 6 gene (IRF6) is one of the most conspicuous genes among a large number of candidate risk genes for non-syndromic cleft lip with or without cleft palate, which is considered to be a multifactorial defect. Variants of IRF6 are also suggested to affect normal craniofacial variations, especially in the area of the nose and the upper lip. In the present study, we used lateral cephalograms to establish the relationship between IRF6 and sagittal nasolabial morphology in healthy East Asian subjects.

DESIGN

Genomic DNA was extracted from 215 Japanese and 226 Korean individuals, and genotyped for five IRF6 single nucleotide polymorphisms (SNPs): rs17389541, rs642961, rs2013162, rs2235371, and rs7802. These SNPs were tested by multiple regression analyses for their association with craniofacial measurements obtained from lateral cephalometrics.

RESULTS

We detected a significant association between the derived variants, rs2013162 and rs2235371 and the distances between a facial bone plane indicated by distance from Nasion and Point A (NA plane) to soft tissue landmarks; the Subalare (NA-Sbal) and the Subnasale (NA-Sn) in the sagittal plane.

CONCLUSION

Our results indicate that IRF6 variants play an important role in the normal range of variation in nasolabial soft-tissue morphology.