Variations in Maxillary Frenal Morphology in a Sample of Newari Children of Bhaktapur

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INTRODUCTION
Frenum is a fold of mucous membrane attaching lip and cheeks to alveolar process of maxilla and mandible.2][3] Frenum has been classified into four types based on its attachment site as given by Mirko et al. while Sewerin has classified into eight different types based on its variations in Dr. Ujjwal Joshi, 1 Dr. Megha Pradhan, 2 Dr. Aastha Neupane, 2 Dr. Nita Lawaju, 1 Dr. Nirma Khadka, 1 Dr. Rajib Chaulagain 3
Based upon the attachment location, mucosal type of frenum was mostly present (204, 60%) followed by gingival type, papillary, and papillary penetrating type (Figure 1, 2).Based Frenum with two or more variations at the same time ---    upon the morphological types, a large number of participants had simple frenum (83.2%) followed by frenum with nodule (7.4%) and frenum with appendix (6.5%, Figure 2, 3).Bifid frenum was present in only one female participant (Table 2, Figure 4).

DISCUSSION
The morphology and location of maxillary labial frenum has clinical significance.Abnormal location of the maxillary frenum causes masticatory problems.Frenum attached to gingival margins interferes with tooth brushing and thus worsens oral hygiene maintenance 15 leading to periodontal problems. 9In small children, the aberrant maxillary frenum also causes breast feeding problem. 16,17Many syndromes such as Ehlers-Danlos syndrome, Infantile hypertrophic pyloric stenosis, Ellisvan Creveld syndrome and Oro-facial-digital syndrome also show variation in frenal attachment. 4This study was carried out to assess the variations of maxillary labial frenum among the Newari children in Bhaktapur region.
Several studies have shown variation in the attachment location and morphology of maxillary labial frenum.[20] Inconsistent to our study, mucosal frenal attachment was to be prevalent in studies done by Kotian et al., 18 Pandian et al. 21We also observed similar findings based on Mirko's classification of maxillary labial frenum according to location.
In line with our findings, Rajkarnikar et al. also observed mucosal as most common type. 22In contrast to our findings, gingival type was mostly observed and then mucosal type in a study done at Dhulikhel Hospital, Nepal by Upadhyay and Ghimire. 11The difference could be due to the sample size taken, variation of ethnicity and geographic location.The present study was performed only among Newari children residing in Bhaktapur.The observation in Chepang community suggested that the mucosal type of frenal attachment was specific to this community. 14However in Newari community, this study observed presence of all types in varying number and percentages.In relation to genderwise distribution of the findings, both male and female gender showed close resemblance and order (Table 2).
Development of the maxillary labial frenum is observed around 8-10 weeks among humans connecting the upper lip tubercle to the palatine papilla.Later on it recedes and takes more apical position. 19,23If the continuous band of maxillary labial frenum crosses in between the two maxillary central incisors, it causes midline diastema and is also reported to affect the growth of premaxillary region. 1,24,25In this instance, the papillary and papillary penetrating frenum attachment are the only two considered as pathological. 15In this study, very less number of the papillary type (6.2%) and papillary penetrating type (4.1%) was also observed.
In the present study, based upon the Sewerin's classification, more than 80% of participants had simple frenum.This was followed by frenum with nodule 25 (7.3%) and frenum with appendix 22 (6.5%).Many studies have reported the simple frenum to be the most common type with differences in other types based on Sewerin's classification. 5,14,18,21,27In line with our results, Rathod et al. reported simple frenum as most common type followed by frenum with nodule and frenum with appendix. 15However study done by Nagavent et al. 27 and Birader et al. 28 the persistent tectolabial frenum was the common type after simple frenum.These differences may be due to geographical variations of study population, diverse ethnicity taken into consideration and the sample size.In the present study frenum with appendix was observed more in male while bifid frenum was only present in one female participant.
The study also has limitations.The main limitation is its convenience sampling method.The study was conducted among the Newari children residing in Bhaktapur, so this study cannot be generalised to whole Newari population of Nepal.

CONCLUSION
This study showed the presence of mucosal type of frenum to be more prevalent followed by gingival type in Newari children.On the basis of morphological type of frenum the simple frenum was the most common type.There was no major variation in gender among the studied population except the frenum with appendix which was mostly found in male.
photographs were taken.Morphology of the maxillary labial frenum was classified into different groups according to the Sewerin's frenum classification, and on the basis of attachment location given by Mirko et al.4The data was then transferred into Statistical Package for the Social Sciences (SPSS) Statistics for Windows, version 16.0 (SPSS Inc., Chicago, Ill., USA) and the data were analysed using descriptive statistics (frequency and percentage).The obtained results were presented in the form of tables.

Table 2 :
Distribution of types of frenum based upon gender.