Facial Soft Tissue Depths in Craniofacial Identification (Part II): An Analytical Review of the Published Sub‐Adult Data*

Abstract

Prior research indicates that while statistically significant differences exist between subcategories of the adult soft tissue depth data, magnitudes of difference are small and possess little practical meaning when measurement errors and variations between measurement methods are considered. These findings raise questions as to what variables may or may not hold meaning for the sub-adult data. Of primary interest is the effect of age, as these differences have the potential to surpass the magnitude of measurement error. Data from the five studies in the literature on sub-adults which describe values for single integer age groups were pooled and differences across the ages examined. From 1 to 18 years, most soft tissue depth measurements increased by less than 3 mm. These results suggest that dividing the data for children into more than two age groups is unlikely to hold many advantages. Data were therefore split into two groups with the division point corresponding to the mid-point of the observed trends and main data density (0-11 and 12-18 years; division point = 11.5 years). Published sub-adult data for seven further studies which reported broader age groups were pooled with the data above to produce the final tallied soft tissue depth tables. These tables hold the advantages of increased sample sizes (pogonion has greater than 1770 individuals for either age group) and increased levels of certainty (as random and opposing systematic errors specific to each independent study should average out when the data are combined).

Soft tissue thickness values for black and coloured South African children aged 6–13 years

“…However, the only significant differences were seen at the pogonion and beneath the chin (t-test, p < 0.05). The difference in STT between males and females varied between 0.01 mm and 0.62 mm, and even the values at the pogonion and beneath the chin landmarks are smaller than 1 mm (pogonion: 0.62mm and beneath the chin: 0.42 mm) which has little practical value [23].…”

“…From Table 3 it can be seen that 76.8% (298/388) of the sample comprised of Coloured children who presented for oral and dental assessment and treatment. In comparison, 23.2% of the sample consisted of Black children (90/388). Table 3 shows that almost equal numbers of Black patients were present in all three age categories.…”

“…The reliability for both measuring events by the first author and the second observer varied between acceptable levels of 0.9924 and 0.9999. Stephan and Simpson [23] argue that, as in the case of adult data, STT difference among sub-adults based on ancestry and sex is of little practical use, and can therefore be disregarded.…”

“…As expected, STT at these landmarks was larger in the 13 year old group compared to the 10 year old group. These differences are all less than 3 mm and the practical value of such small differences have been questioned [18,[23][24][25]. In practical terms few significant differences were seen between age groups and the STT increased at only at two landmarks with age.…”

“…They concluded that, regardless of the strengths and weaknesses of each method, one method was not superior to the other. They suggested that STT data be pooled without considering the different methodologies [18,[23][24][25]. Recent studies favored either ultrasound [16] or CT [20,21].…”