The timing of mandibular tooth formation in two African groups

Abstract

Background: Ethnic differences in the timing of human tooth development are unclear. Aim: To describe similarities and differences in the timing of tooth formation in two groups of Sudanese children and young adults. Subjects and methods: The sample consisted of healthy individuals from Khartoum, Sudan, aged 2-23 years. The Northern group was of Arab origin (848 males, 802 females) and the Western group was of African origin (846 males, 402 females). Each mandibular left permanent tooth from first incisor to third molar was assessed from dental radiographs into one of 15 development stages. Mean ages at entry for 306 tooth stages were calculated using probit regression in males/females in each group and compared using a t-test. Results: Mean ages were not significantly different in most tooth stage comparisons between ethnic groups for both males (61/75) and females (56/76), despite a tendency of earlier mean ages in the Western group. Mean ages for most tooth stage comparisons between males and females (137/155) were not significantly different within ethnic groups suggesting low sexual dimorphism. Conclusion: The mean ages of most mandibular tooth formation stages were generally not significantly different between ethnic groups or between males and females in this study.

Dental age estimation in Somali children and sub-adults combining permanent teeth and third molar development

“…The second study hypothesis was that dental age predictions in a Somali population behave similarly to comparable age predictions in other studied populations. An abundant number of age estimation outcomes in Black populations have been reported and discussed in the literature [ 12 , 20 , 33 , 35 , 40 , 41 , 43 – 46 , 48 – 50 , 59 – 63 ], but they are not comparable with the present study due to differences in study set-ups, sampling, variation in age distribution, teeth considered, age predictors used and staging techniques and age estimation methods applied. Models combining PT + TM have been validated in United Arab Emirati, Brazilian, Japanese and Malaysian children and sub-adults [ 27 – 30 ].…”

“…In the literature, controversies still exist regarding possible differences in the dental development between Black and other populations [ 12 , 40 – 42 ], although more and more evidence of equality has been appearing [ 11 , 20 , 33 , 35 , 43 – 46 ]. Studies on the dental development in sub-Saharan populations and in Somalis, indigenous to Northeast Africa, are few, however [ 12 , 41 , 47 ].…”

“…Recently, permanent tooth development has been studied in the South-African Black population [ 46 ], in Botswanan children [ 40 ], and in Somali children born in Finland [ 44 ]. Studies of third molar development in sub-Saharan populations were also recently published on South African [ 35 , 43 , 48 – 50 ], Sudanese [ 20 ], Kenyan [ 45 ], Botswanan [ 51 ], Nigerian and Senegalese individuals [ 35 ], and on Northeast Africans from Libya [ 52 ], Morocco [ 53 ] and Sudan [ 20 ].…”

Age estimation based on Willems method versus new country-specific method in South African black children

“…The overall MAE when using the Willems BC method is about 22 days larger compared to the Finland, France, South Korea and Sweden not to show major differences [39], apparently also not within two ethnic groups from Sudan. [40] The timing of dental development in children of subsaharan descent has not been studied at large. Some reports were based on datasets of all permanent teeth either including or excluding third molars or on third molars only.…”

Does age estimated from teeth forming in different early life periods show differential discrepancy with known age?

“…The subsequent underestimation of chronological age, which we ascribe to differences in environment, might on the other hand be suggested as being due to genetically based population differences in tooth size and development. While this is a possibility, existing research indicates that observed differences between populations are primarily the result of environmental factors (Cardoso, 2009), with comparisons of samples from diverse geographic origins finding no significant differences in the timing of tooth formation (Elamin, Hector, & Liversidge, 2016; Liversidge, 2003; Liversidge, Speechly, and Hector, 1999; Maber, Liversidge, and Hector, 2006). Of the scarce studies that have examined population variation in tooth length specifically, one found only two teeth differed in size between geographically diverse samples (Smith, Wax, and Adler, 1989), while an analysis of chronologically diverse samples determined only the root length of one tooth differed (Smith et al, 1986).…”