ABSTRACT

Introduction: The objective of the study was to determine the distribution of two morpho-genetic traits namely cerumen type and earlobe attachment among Niger Deltans.

Methods: This observational research embraced descriptive cross-sectional survey method and involved the use of data form, direct observation and interviews. Cluster sampling was employed in this study which involved 2304 subjects. Cerumen types (dry and wet) were determined by visual examination. The two fold classification of earlobe attachment types by Powell and Whitney were followed in the study.

Results: The Niger Deltans displayed a higher frequency of attached ear lobes (58.98%) and a low frequency of free ear lobes (40.97%). The gender difference was not significant (P > 0.05). The wet cerumen was seen to be more frequent. The wet cerumen was seen to be more frequent in the females. The gender difference in the distribution of cerumen type was not significant (P > 0.05).

Conclusion: The distribution of earlobe attachment and cerumen type in the Niger Delta region has been documented. The Niger Deltans possess a higher frequency of attached ear lobes. The wet cerumen was more frequent in the females.

Keywords: Distribution, Earlobe, Attachment, Cerumen, Niger Deltans

Earlobe attachment refers to the way the bottom of the ear is connected to the head. “Free” dominant genes cause the ear to be lobed and the attachment to the head is genetically in an upward direction. The

recessive “attachment” gene results in an upward earlobe and a more horizontal attachment to the head (Lai and Walsh, 1966).

Figure 1: Photograph of attached earlobe

Two genetically determined types of cerumen (earwax) exist: the wet type, which is dominant, and the dry type, which is recessive. The wet type of earwax has a higher concentration of lipid and pigment granules (50% lipid) in the substance than the dry type (30% lipid) (Guest et al.,

Figure 2: Photograph of free earlobe

2004). Dry earwax is frequent in East Asians, whereas wet earwax is common in other populations (Yoshiura et al., 2006). Earwax type has been used by anthropologists to track human migratory patterns in some parts of the world (Bass and Jackson, 1977).

A study was done on the pattern of morphogenetic traits combination amongst the population of Ekpoma in Nigeria (Nwaopara et al., 2009). A remarkable research was done on morphogenetic traits combination pattern amongst the population of Ekpoma, Nigeria: focus on tongue rolling, ear lobe attachment, blood groups and genotypes (Nwaopara et al., 2008). A study considered the o c c u r r e n c e s o f t h e f r e q u e n c y d i s t r i b u t i o n o f morphological, genetical and behavioural traits among the people of Indian region (Bhasin et al., in 1992). The study area is the Niger Delta region in Nigeria. The Niger Delta is the southernmost region of Nigeria. Although it occupies ninety percent of the Nigerian coastline, it is specifically between the Mahin River estuary in the west and the Cross River estuary in the east. The region has been producing oil since 1956 (Enemugwem, 2010).

Figure 3: Photograph of dry ear wax  Figure 4: Photograph of wet ear wax

Literature search reveals dearth of data on the distribution of cerumen type and earlobe attachment in the Niger Delta Region in Nigeria. The objective of the study was to determine the distribution of morpho-genetic traits namely cerumen type and earlobe attachment among Niger Deltans. This study provides a comprehensive data for use in anthropology and forensic medicine.

MATERIALS AND METHODS

The study which is an observational research embraced the descriptive cross-sectional survey method and involved the use of data form, direct observation and interviews. Cluster sampling was employed in this study and the research involved 2304 subjects. The research subjects met the following criteria: Parents and grandparents must be from Niger Delta and subjects had no history of craniofacial trauma or disorder.

Cerumen types (dry and wet) were determined by visual examination. Any cerumen which was grey and flaky was regarded as dry. The wet type was the class for honey-brown to dark-brown and moist cerumen. The two fold classification of earlobe attachment types of Powell and Whitney (1937) were followed in the study. People with earlobes that curve up between the lowest point of the earlobe and the point where the ear joins the head were regarded as having free or unattached earlobes. Others with earlobes that blend in with the side of the head were noted as having attached earlobes. Ethical clearance was sought from the Research and Ethics Committee in the Faculty of Basic Medical Science of the Delta State University prior to the commencement of this research. All subjects were verbally informed about the aim of the study and they agreed to participate.

Data collection was done between the first day and the last day of the months of March and July respectively in the year 2013. Statistical analyses were performed using SPSS version 18. Results were arranged according to gender to ascertain the occurrence of sexual dimorphism. The chi-square test was useful in this regard. The morpho-genetic traits were compared between the genders. Values at P<0.05 were termed significant.

RESULTS

The results revealed that 1147 (49.79%) males and 1157 (50.21%) females participated in the present study.

Table 1: The distribution of earlobe attachment among Niger Deltans.

The Niger Deltans possess a higher frequency of attached ear lobes (58.98%) and a low frequency of free ear lobes (40.97%). The gender difference was not significant (P > 0.05).

Table 2: The distribution of cerumen type among Niger Deltans

Table 2 shows that the wet cerumen was seen to be more frequent. The wet cerumen was seen to be more frequent in the females. The gender difference was not significant (P > 0.05).

DISCUSSION

The frequency of dry cerumen was shown to be low (37.5%) in the sampled Niger Deltan population. This study did not agree with the high frequencies of dry type cerumen found in Eskimos of the Nome and Bethel areas of Alaska (Bass and Jackson, 1977). The frequencies of dry cerumen were also shown to be high in Mongoloid populations and low among Europoids. Intermediate frequencies were found among peoples of subequatorial Africa. Findings from some studies have exposed the potential for using cerumen type as a marker in population and anthropological studies (Ibraimov, 1991).

The present study did not concur with the findings of Yoshiura et al. (2006) who documented that dry earwax is seen in up to 95% of East Asians, but in no more than 3% of people of European and African origin. Yoshiura et al. (2006) also stated that populations in Southern Asia, the Pacific Islands, Central Asia, Asia Minor, and Native North Americans and those of Asian ancestry, fall in the middle with dry earwax incidence ranging from 30 to 50 percent. Petrakis et al. (1967) determined the occurrence of sticky and dry cerumen in 483 Indians from various tribes of the United States and saw elevated frequencies of the dry cerumen in Indians of pure ancestry. Among the Niger Deltans, dry cerumen was seen to have almost equal occurrences in males and females. This did not concur with

Singh and Sengupta who in 2004 did research on the Assamese Sikhs in India. They saw that dry cerumen was highly frequent in the males (61.54%), while the wet type predominated in females (55.77%). The present study concurred with that of Singh and Sengupta ( 2004) with reference to the non-significant gender difference (P > 0.05) seen in the cerumen type.

The present analysis of data on ear lobe attachment revealed an incidence of attached ear lobe of 58.98%. The frequency of attached ear lobes seen did not concur with Nwaopara et al., (2008) who reported 31.61% for attached earlobe and 63.39% for free earlobe. The present study did not concur with Kalia and Gupta (1978) who observed higher incidence of free ear lobes (73.84%). The present study did not concur to that where the frequency of free ear lobes was found to be in the range of 56% to 74% in five endogamous groups of Haryana by Yadav et al., (2000). The present analysis of data on ear lobe attachment differed from that by Singh and Sengupta in 2004 who researched on the Indians and saw that the frequency of free earlobe (83.65%) is higher than attached earlobe (16.35%). They observed that in females, frequency of free earlobe show relatively higher incidence (90.38%) than in the males (76.92%). The sex variation as revealed from their chi-square test was significant (0.01 >P) (Singh and Sengupta, 2004). This study did not concur with theirs as the males in this study had frequency of free earlobe which showed relatively higher incidence (21.66%) than that of the females (19.31%).

CONCLUSION

The distribution of earlobe attachment and cerumen type in the Niger Delta region has been documented. The Niger Deltans possess a higher frequency of attached ear lobes. The wet cerumen was more frequent in the females.

REFERENCES

1. Bass E.J. and Jackson J.F. (1977). Cerumen types in Eskimos. American Journal of Physical Anthropology, 47 (2): 209–210.

2. Bhasin M.K., Walter H. and Danker-Hopfe H. (1992). The distribution of genetical, morphological and behavioural traits among the people of lndian Region. Dehli, Kamla-Raj Enterprises.

3. Enemugwem H.  (2010).  The  Niger  Delta  of Nigeria: A World Class Oil Region in Africa, 2000-2006. Africana Journal, 4 (1) 6: 165-166.

4. Guest J.F., Greener M.J., Robinson A.C. and Smith A.F. (2004). Impacted cerumen: composition, production, epidemiology and management. Quarterly Journal of Medicine, 97 (8): 477–488.

5. Ibraimov A.I. Cerumen (1991). phenotypes in certain populations of Eurasia and Africa. American Journal of Physical Anthropology, 84: 209-211.

6. Kalia V.K. and Gupta A.K. (1978). Earlobe types among the Punjabis. Indian Journal of Physical Anthropology and Human Genetics, 4: 69-74.

7. Lai L.Y.C. and Walsh R.J. (1966). Observations on ear lobe types. Acta Genetica, 16: 250-257.

8. Nwaopara A.O., Anibeze C.I.P., Akpuaka F.C. and Agbontaen O.F. (2008). Morphogenetic Traits Combination Pattern amongst the population of Ekpoma, Nigeria: Focus on Tongue Rolling, Ear Lobe Attachment, Blood groups and Genotypes. African Journal of Biotechnology, 7: 3593-3598.

9. Nwaopara A.O., Anibeze C.I.P., Akpuaka F.C. and Uhumuavbi E. (2009). The Pattern of Morphogenetic Traits Combination amongst the population of Ekpoma, Nigeria: Focus on

10. Dimples, Widows Peak, Blood groups and Genotypes. The Internet Journal of Biological Anthropology, 3 (2).

11. Petrakis N.L., Molohon K.T. and Tepper D.J. (1967). Cerumen in American Indians: genetic implications of sticky and dry types. Science, 158: 1192-1193.

12. Powell E.F. and Whitney D.D. (1937). Ear lobe inheritance: an unusual three-generation photographic pedigree chart. Journal of Heredity, 28: 184-186.

13. Singh J. and Sengupta S. (2004). Some Morpho-genetic and Behavioural Traits among the Assamese Sikhs. Anthropologist, 6 (4): 253-255.

14. Yadav J.S., Yadav A.S. and Chadha P.C. (2000). Studies on Morphogenetic and Behavioural Traits in five endogamous groups of Haryana. Journal of Pan African Studies, 2: 329-332
15. Yoshiura K., Kinoshita A., Ishida T., Ninokata A., Ishikawa T., Kaname T. et al. (2006). (39 co-authors). A SNP in the ABCC11 gene is the determinant of human earwax type. Nature Genetics, 38 (3): 324-330

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ABSTRACT

Introduction: The aim of this study was to determine the tooth occlusion pattern among the Niger Deltans in Nigeria.

Materials and Methods: The study adopted an observational research design. This descriptive cross-sectional survey involved the use of data form and direct observation. The research involved 2304 subjects and multistage sampling; a complex form of cluster sampling was employed. Tooth occlusion pattern were classified following the fourfold models. Subjects were classified as having any of the following: edge to edge, mild overbite, severe overbite and negative overbite. Data obtained were subjected to statistical analyses using chi-square test, with the aid of the Statistical Package for the Social Sciences, version 18. P-value < 0.05 was considered significant.

Results: The results of the study revealed the frequency of mild overbite as the highest (male = 26.13%, female = 25.39%) which was followed by edge to edge type of tooth occlusion (male = 16.28%, female = 18.75%). The incidences of both severe and negative overbite were observed more in males than females (P > 0.05).

Conclusion: This research has elucidated human variability in the tooth occlusion pattern of the Niger Deltans.

Keywords: Tooth, Occlusion, Pattern, Niger Deltans

INTRODUCTION

Dental occlusion refers to the contact between the teeth of the upper jaw (maxillary teeth) and the teeth of the lower jaw (mandibular teeth). The term Malocclusion means the teeth are not aligned properly which  is  most  often  hereditary.  There  are  different categories  of  occlusion.  According  to  Eveleth’s classification  of  tooth  occlusion  pattern  (1972)  the categories are: edge to edge which means the upper teeth and the lower teeth align to each other, mild overbite means the upper teeth slightly overlap the lower teeth and severe overbite is more overlap, negative overbite is when the lower jaw overlap the upper jaw. Tooth occlusion pattern was studied and classified in North Eastern Brazilians [1]. Literature search reveals dearth of data on the distribution of tooth occlusion pattern in the Niger Delta Region in Nigeria. This study provides a comprehensive data for use in orthodontics, anthropology and forensic medicine. The aim of this study was to determine the tooth occlusion pattern among the Niger Deltans. The Niger Delta region consists of present-day Bayelsa, Delta, and Rivers States. The region also includes Abia, Akwa-Ibom, , Edo, Imo and Ondo States. There are about 31 million people of more than 40 ethnic groups including the Bini, Efik, Esan, Ibibio, Igbo, Annang, Oron, Ijaw, Itsekiri, Yoruba, Isoko, Urhobo, Ukwuani and Kalabari, among the inhabitants in the Niger Delta, speaking about 250 different dialects [2].

MATERIALS AND METHODS

The study area is Niger Delta and the study adopted an observational research design. This descriptive cross-sectional survey involved the use of data form and direct observation. The research involved 2304 subjects and multistage sampling; a complex form of cluster sampling was employed. Tooth occlusion pattern were classified following the fourfold models [1]. Subjects were classified as having any of the following: edge to edge, mild overbite, severe overbite and negative overbite (figures 1to 4). Edge to edge occlusion pattern was the impression for an occlusion in which the incisal edges of the maxillary incisors meet the incisal edges of the mandibular incisors. Mild overbite was the class when the upper anterior teeth overlap the lower anterior teeth creating a vertical overlap of the anterior teeth which is 2-3 millimeters. Severe overbite was defined when there was excess amount or percentage of vertical overlap of the lower incisors (greater than 3mm or 30% percent or 1/3 rd the clinical crown height of the mandibular incisors) by the upper incisors. Negative overbite was when the lower anterior teeth overlap the upper anterior teeth. The subjects with history or clinical presentation of pathological conditions, trauma or fracture of the jaw were excluded from the study.

Prior to this study, approval was obtained from the Anatomy Department Research and Ethics Committee in the Delta State University, Abraka. Consent was also obtained from each participant. Statistical analyses were performed using SPSS version 18. The tooth occlusion patterns were compared between the genders. Values at P<0.05 were considered significant. The chi-square test was useful in the bid to achieve this

RESULTS

Table 1: The gender of the Niger Deltans.

Table 2: The tooth occlusion pattern among the Niger Deltans.

Table 2 revealed that the frequency of mild overbite type of tooth occlusion was found to be the highest which was followed by edge to edge bite. The negative overbite was rare among the participants. The gender difference in the tooth occlusion pattern among Niger Deltans was not significant (P > 0.05).

DISCUSSION

The present study among the Niger Deltans in Nigeria saw the frequency of mild overbite as the highest (male = 26.13%, female = 25.39%) which was followed by edge to edge type of tooth occlusion (male = 16.28%, female = 18.75%). The incidences of both severe and negative overbite were observed more in males than females. This study concurred with one done among the Assamese Sikhs in India. They saw that the frequency of mild overbite type of tooth occlusion was found to be the highest (male = 44.90%, female = 54.00%) which was closely followed by edge to edge bite (male = 36.73%, female 32.0%). They noted that the incidence of negative overbite was observed more in males (16.33%) than females (10.00%). Their study revealed that severe overbite type was rare among them (male = 2.04%, female = 4.00%). They documented that bisexual variation had no significant differences (0.80 > P > 0.70) among them [3]. The gender difference in the tooth occlusion pattern among the Niger Deltans was not significant (P > 0.05) just like the study done among the Assamese Sikhs [3].

The Mishing tribals had a predominance of edge to edge bite of dental occlusion pattern and the bisexual differences observed were not significant. The percentage figures with regards to overbitting among them are much lower than the corresponding figures observed in this study [4]. The different studies compared and discussed above portrayed differences in the tooth occlusion considered. There may be reasons for this such as racial origin, methodology and age.

CONCLUSION

This research has elucidated human variability in the tooth occlusion pattern of the Niger Deltans.

REFERENCES

1. Eveleth P.B. (1972). An anthropometric study of North Eastern Brazilians. American Journal of Physical Anthropology, 37:

2. Sandeep G., Sonia G. (2012). Pattern of Dental Malocclusion in Orthodontic Patients in Rwanda: A Retrospective Hospital Based Study. Rwanda Medical Journal, 69 (4): 13-18.

3. Vegesna M., Chandrasekhar R., Chandrappa V. (2014). Occlusal Characteristics and Spacing in Primary Dentition: A Gender Comparative Cross-Sectional Study. International Scholarly Research Notices, 2014.

4. Onyeaso C.O., Sote E.O. (2002). A study of malocclusion in the primary dentition in a population of Nigerian Children. Nigerian Journal of Clinical Practice, 5 (1): 52-56.

5. CRS Report for Congress, Nigeria: Current Issues. Updated 30 January 2008.

6. Singh J., Sengupta S. (2004). Some Morpho-genetic and Behavioural Traits among the Assamese Sikhs. Anthropologist, 6 (4): 253-255.
7. Sengupta S. (1993). Physical Anthropology of the Koch Population of North East India. Mittal Publications, Delhi.

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