McNamara Cephalometric Analysis oF Newars of Kathmandu

Introduction: Standardized cephalogram is used for the orthodontic diagnosis and treatment planning and the measured values of the craniofacial structures are compared with the peer group having similar age, gender and ethnicity. However, this standardized comparison has not been possible so far for Newar ethnic group. Objective: To determine cephalometric norms of Newar adults of Kathmandu using McNamara analysis and to assess gender difference within the group. Materials & Method: Newar Indo-Aryan descendents aged 18-27 years were screened based on inclusion criteria. Lateral cephalometric radiographs of 62 untreated Newar adults (20 males and 42 females) were used. Manual tracing of the lateral cephalograms were performed and descriptive statistics were obtained. Comparative test was conducted within Newars to evaluate gender diversity at the significance level p≤0.05. Result: Craniofacial structures of male and female Newars were significantly different. Parameters showing these differences were Effective Mid Face Length, Effective Mandibular Length, Lower Anterior Facial Height. Conclusion: Standardized comparison with the peer group separately for male and female should be done when analysing cephalometry for any ethnic group. Key-words: Cephalometric analysis, McNamara, Newar MATERIALS AND METHOD Ethical clearance was obtained from Institutional Review Board to conduct this study. Convenient sampling comprising of 62 subjects including 20 males and 42 females were screened for Newar Indo-Aryan descendents aged 18-27 years. Inclusion criteria were Angle’s Class I molar and canine relation, normal overjet and overbite, symmetric face and acceptable facial profile. Subjects were excluded having craniofacial abnormalities, history of orthodontic or surgical treatment and having proximal caries or prosthesis. Informed and signed consent was taken from all participants. The lateral cephalometric radiographs were taken in natural head position15 with right side facing the cassette. Sordex Cranex Excel Ceph 71 Kvp 6 mA was exposed for 1.2 seconds by the operator standing behind the lead door. The distance from the source to the mid sagittal plane was 134 cm and the distance from mid sagittal plane to x-ray film was 18 cm. Linear measurements had 13% enlargement. The qualities of the radiographs were checked before printing. Landmark localization and manual tracing of the lateral cephalograms were performed by the principal researcher. Intra-observer


MATERIALS AND METHOD
Facial Height of the Turkish population than Newars of Kathmandu.These parameters were compared separately for male and female as the Turkish population also showed gender diversity.Downs analysis of the Nepalease population 13 showed no significant differences in craniofacial structure between male and female.
Whereas parameters of McNamara analysis of Newars revealed significant differences in male and female.These differences can also be seen in Turkish population.When the position of Maxilla and Mandible was compared in reference to Nasion Perpendicular, both Maxilla and Mandible of the Newars was found to be positioned more anteriorly than the Turkish.

CONCLUSION
Ethnic and gender diversity of the craniofacial structures of Newars of Kathmandu have been observed.Hence for diagnosis and treatment planning of Newar individuals, standardized comparison separately for male and female will be justifiable.
Ethical clearance was obtained from Institutional Review Board to conduct this study.Convenient sampling comprising of 62 subjects including 20 males and 42 females were screened for Newar Indo-Aryan descendents aged 18-27 years.Inclusion criteria were Angle's Class I molar and canine relation, normal overjet and overbite, symmetric face and acceptable facial profile.Subjects were excluded having craniofacial abnormalities, history of orthodontic or surgical treatment and having proximal caries or prosthesis.Informed and signed consent was taken from all participants.The lateral cephalometric radiographs were taken in natural head position15 with right side facing the cassette.Sordex Cranex Excel Ceph 71 Kvp 6 mA was exposed for 1.2 seconds by the operator standing behind the lead door.The distance from the source to the mid sagittal plane was 134 cm and the distance from mid sagittal plane to x-ray film was 18 cm.Linear measurements had 13% enlargement.The qualities of the radiographs were checked before printing.Landmark localization and manual tracing of the lateral cephalograms were performed by the principal researcher.Intra-observer Orthodontic Journal of Nepal, Vol. 8 No. 1, June 2018

Table 1 . Demographic data of Newar sample
51adhan R, Rajbhandari A, Manandhar P, Maharjan S : McNamara Cephalometric Analysis oF Newars of Kathmandu *Significant at p<0.01Figure 1. Histogram showing normal distribution parameters of the samples were expressed as mean, range and standard deviation.The descriptive data showed biological variability of two series of data between the gender groups.Wide range of data was reflected by minimum and maximum values of Pogonion to Nasion Perpendicular.Spread out of the data of this parameter was also reflected by standard deviation 6.96 and 5.33 in male and female respectively.Comparison of the Maxillary, Mandibular, and Vertical Components of craniofacial region and dentoalveolar parameters of Newar male and female adults are presented in Table 2.There was significant gender difference regarding the craniofacial structures.Male subjects had significantly larger craniofacial parameters than females in: Effective Midface Length, Effective Mandibular Length, Maxillomandibular Differential and Lower Anterior Facial Height.Mandibular Plane Angle was significantly steeper in Newar females compared to males.Dentoalveolar positions were not significantly different between the gender groups. 19ar females presented with smaller craniofacial dimension compared to males.In spite of smaller Effective Maxillary Length in female subjects (82.21 mm females, 87.64 mm males); maxilla was more anteriorly positioned compared to male subjects as expressed by the parameter also result in steep Mandibular Plane.20 Negative Facial Axis Angle in Newar females (-2.05 o females, -0.55 o males) indicated narrower anteroposterior dimension of the face compared to male subjects21Negative Facial Axis angle would also contribute to vertical development of face.5