Role of Facial Index and Odontometric Parameters in the Establishment of Stature and Gender of Individuals.

BACKGROUND: Dental anthropology is an important aspect of bioarchaeology and forensic anthropology. In forensic anthropological studies, identifying an unknown individual from a mangled and decomposing body is a challenging task. Cranial remains are the only critical clues available for personal identification. Age, sex, and stature are significant parameters in establishing the identity of an unrecognized individual. Stature is the natural height of the individual in an upright position. Stature can be estimated from various parts of the body such as long bones, short bones, and skull. Few studies conducted in specific population have established a correlation for predicting stature from cephalometric and odontometric parameters. Thus, the present study was conducted to determine stature and gender based on cephalometric and odontometric parameters in the population of Tamil Nadu. AIMS: The aim of this study was to investigate the possibility of predicting the stature and gender of an individual based on odontometric measurements, facial height, and bizygomatic width.
MATERIALS AND METHODS: A total of seventy individuals in the age group of 18-24 years were selected for the study. The facial height, bizygomatic width and length ,mesiodistal and labiolingual diameter of clinical crown of maxillary central,lateral and canine teeth of both the right and left quadrants were measured. The values were analyzed statistically. Through this analysis, regression equations for estimation of stature from odontometric and facial index were derived.
RESULTS: Pearson correlation test was carried out to establish a correlation between the stature and the measured parameters. Regression analysis was carried out to establish stature from the odontometric and facial index of the individual. The regression equations were used to get estimated stature in the same sample of volunteers from which regression equations were obtained. Tabulated results showed a probable correlation between various parameters.
CONCLUSION: In our study, a positive correlation between cephalometric measurements, gender, crown length of permanent left central incisor, and combined mesiodistal diameter of permanent maxillary anteriors with stature was found. This can be used as a supplementary method for estimating the stature of unknown human bodies. Copyright:

INTRODUCTION

Stature, gender, age, and ancestry are important parameters of anthropometry, which helps to establish a biological Profile. In forensic anthropology, metric, nonmetric, and biochemical techniques are used to establish the identification of unknown human body remains. Stature is one of the distinct visible factors of an individual.[1] Sex and race determination can reduce the number of mismatches in forensic cases. Gender determination can be done by craniometry,[2] osteometry, odontometry, and DNA analysis. Although DNA analysis is the most precise method Lacks of facilities and the cost factor may be a hindrance, it is not used widely. Linear dimension method is a simple, affordable, and reliable technique, which acts as an excellent parameter.[3] This study was conducted to assess the linear dimension of the maxillary anterior teeth, facial height, and bizygomatic width as an anthropometric tool for stature and gender estimation.

MATERIALS AND METHODS

The study was conducted in the Department of Oral Pathology and Microbiology, Faculty of Dental Sciences, Sri Ramachandra Institute of Higher Education and Research (SRIHER), Porur, Chennai. The present study was carried out after the approval from SRIHER Intuitional Ethical Committee (CSP/17/MAY/58/166). Seventy undergraduate student volunteers were participated after fulfilling the requirements.

Inclusion criteria

Volunteers with parents and grandparents of Tamil origin, healthy state of teeth and periodontium, and fully erupted permanent maxillary anteriors were included in the study.

Exclusion criteria

Abnormal aligned maxillary anteriors, orthodontic treatment, and any history of trauma were excluded from the study.

Students were informed about the nature of the study, and written informed consent was obtained. The demographic data of individuals were recorded. The height of the volunteers was measured using a wall-mounted height rod with the volunteers standing erect with the Frankfurt plane parallel to the platform. The volunteer's heels should not be raised from the platform during the recording. The morphological facial height was measured from nasion (n) to gnathion (gn) and also facial width was measured the distance between right and left zygion (zy). All odontometric measurements were measured on the cast of the same individuals. The maxillary impressions of all the volunteers were made with alginate and study models were prepared with dental stone. The mesiodistal width and clinical crown length of permanent maxillary central incisors and canine teeth were measured in cast models using electronic digital caliper (Germany) [Figure 1]. In addition, combined mesiodistal diameters of six anteriors were measured. These measurements were carried out by two investigators; Cohen's kappa value is 0.96 for the desired inter-examiner reliability. The collected data were entered in an Excel sheet and were analyzed using Statistical Package for the Social Sciences version 11.5 software (SPSS Inc,Chicago IL).

Figure 1

The odontometric analysis

RESULTS

Various measurements obtained from the volunteers were used to get estimated stature using the regression equations. The mean age of the volunteers was 22.48 + 1.44 (20–24) years. The height of males varied from 163 to 187 with a mean value of 173.643 cm, in case of females 147–167 with a mean value of 159.320 and standard deviations shown in Table 1.

Table 1

Mean and standard deviation of height of study individuals

Gender	n	Mean	SD	SE mean
Height of the individual (cm)
0	40	159.320	4.5526	0.7198
1	30	173.643	5.8371	1.0657

SD: Standard deviation, SE: Standard error

Table 2 represents mean, standard deviations of the various craniometric measurements of males and females. Based on facial index in our study population, various facial morphologies are represented in Graph 1. In odontometric analysis, crown length and mesiodistal diameter of right and left teeth were significantly greater for males than females. Summation of all anterior teeth and summation of central incisors and canines for each type of measurements were also compared between males and females, and a significant difference was observed for all cases [Table 3].

Table 2

Mean and standard deviation of facial parameters

Parameters	Gender	n	Mean	SD	SE mean
Facial height	Female	40	88.0275	6.19930	0.98019
	Male	30	94.0600	6.79262	1.24016
Bizygomatic width	Female	40	101.4875	7.18503	1.13605
	Male	30	107.8400	6.55521	1.19681
Facial index	Female	40	86.8300	3.86730	0.61147
	Male	30	87.2640	4.33316	0.79112

SD: Standard deviation, SE: Standard error

Graph 1

Various facial morphologies

Table 3

Significance mean value of odontometric parameters

Odontometric parameters (cm)	Male		Female
	Minimum-maximum	Mean	Minimum-maximum	Mean
Mesiodistal diameter of 11	7.4-10.5	8.595	6.89-9.66	8.45925
Clinical crown length of 11	8.11-11.56	9.60000	7-10.65	8.92095
Mesiodistal diameter of 21	7.24-9.98	8.503	6.89-9.66	8.4295
Clinical crown length of 21	7.5-11.1	9.665667	7.31-11.4	9.17925
Mesiodistal diameter of 13	6.65-11.17	8.002	6.43-9.34	7.63225
Clinical crown length of 13	7.12-11.50	8.786667	6-10.12	8.1515
Mesiodistal diameter of 23	6.9-9.10	7.92166	6.50-8.34	7.54025
Clinical crown length of 23	6.65-11.17	8.769	5.26-9.56	8.14625
Combined mesiodistal distance of maxillary anteriors	41.6-52.81	46.76967	37.6-49.92	44.9775

In Tables 4a–d, multiple regression analysis showed included all the parameters of odontometric and craniometric measurements with height of the individual. R square value of this model is 0.054, Statistically significant correlation to stature.

Table 4a

Regression analysis

Regression analysis-
Model	Variables entered	Variables removed	Method
1	Crown length of 23, mesiodistal diameter of 21, facial index (mm), gender, mesiodistal diameter of 13, crown length of 11, mesiodistal diameter of 23, mesiodistal diameter of 11, crown length of 13, crown length of 21, combined mesiodistal distance of maxillary anteriors		Enter

Table 4d

Coefficients of dependent variable

Model 1	Unstandardized coefficients		Standardized coefficients	t	Significance
	B	SE	β
Constant	121.827	22.275	5.469	0.000
Facial index (mm)	0.501	0.256	0.231	1.961	0.054

SE: Standard error

In each model, the weakest correlation parameters were excluded. [Table 5]. Prediction of stature is done based on facial index, combined mesiodistal distance of maxillary anteriors, gender, and crown length of left maxillary central incisors (21). Tabulated results showed a probable correlation between parameters [Table 6]. The regression equations were used to get estimated stature in the same sample of volunteers from which regression equations were obtained.

Table 5

Model of excluded parameters

Model	Beta	t	Significance	Partial correlation	Collinearity statistics Tolerance
2
Mesiodistal diameter of 23	−0.004b	−0.034	0.973	−0.005	0.365
3
Mesiodistal diameter of 23	−0.001c	−0.013	0.989	−0.002	0.367
Crown length of 13	−0.030c	−0.268	0.790	−0.040	0.340
4
Mesiodistal diameter of 23	−0.005d	−0.044	0.965	−0.007	0.376
Crown length of 13	−0.020d	−0.189	0.851	−0.028	0.380
Mesiodistal diameter of 11	0.023d	0.204	0.839	0.030	0.321
5
Mesiodistal diameter of 23	−0.009e	−0.083	0.934	−0.012	0.380
Crown length of 13	−0.012e	−0.121	0.904	−0.018	0.392
Mesiodistal diameter of 11	0.029e	0.266	0.792	0.039	0.330
Mesiodistal diameter of 21	0.048e	0.384	0.702	0.056	0.261
6
Mesiodistal diameter of 23	−0.021f	−0.217	0.829	−0.031	0.403
Crown length of 13	−0.035f	−0.414	0.681	−0.060	0.565
Mesiodistal diameter of 11	0.025f	0.231	0.818	0.033	0.331
Mesiodistal diameter of 21	0.053f	0.434	0.666	0.062	0.263
Crown length of 23	−0.040f	−0.565	0.575	−0.081	0.788
7
Mesiodistal diameter of 23	−0.005g	−0.053	0.958	−0.008	0.416
Crown length of 13	−0.058g	−0.795	0.431	−0.113	0.721
Mesiodistal diameter of 11	0.035g	0.321	0.750	0.046	0.334
Mesiodistal diameter of 21	0.047g	0.385	0.702	0.055	0.264
Crown length of 23	−0.047g	−0.672	0.505	−0.096	0.800
Crown length of 11	−0.095g	−0.918	0.363	−0.130	0.366
8
Mesiodistal diameter of 23	0.033h	0.367	0.715	0.052	0.501
Crown length of 13	−0.056h	−0.758	0.452	−0.107	0.722
Mesiodistal diameter of 11	0.038h	0.350	0.728	0.049	0.335
Mesiodistal diameter of 21	0.041h	0.332	0.741	0.047	0.264
Crown length of 23	−0.032h	−0.463	0.645	−0.065	0.831
Crown length of 11	−0.102h	−0.997	0.324	−0.140	0.368
Mesiodistal diameter of 13	0.082h	1.017	0.314	0.142	0.600

Table 6

Strong significant correlation parameters

Parameters	Unstandardized coefficients		Standardized coefficients β	t	Significance	95.0% CI for B
	B	SE				Lower bound	Upper bound
Constant	72.203	15.571	4.637	0.000	40.943	103.463
Facial index (mm)	0.498	0.143	0.223	3.489	0.001	0.211	0.784
Combined mesiodistal distance of maxillary anteriors	0.571	0.240	0.187	2.380	0.021	0.089	1.052
Gender	11.343	1.264	0.626	8.974	0.000	8.805	13.880
Crown length of 21	1.984	0.759	0.202	2.615	0.012	0.461	3.506

SE: Standard error, CI: Confidence interval

Table 6 shows strong significant correlation parameters.

Table 4c

ANOVA values

Model 1	Sum of squares	df	Mean square	F	Significance
Regression	284.366	1	284.366	3.845	0.054b
Residual	5029.004	68	73.956
Total	5313.370	69
Dependent variable: Height of the individual (cm) Predictors: (Constant), facial index (mm)

DISCUSSION

Regression analysis is the best method for estimating stature.[4] Cranial dimensions are found to be more reliable and precise for predicting stature.[5] Population-specific studies are needed to develop the regression equation for the accuracy of stature estimation.[6] Thus, in the present study, we correlated the facial index and clinical crown dimensions of permanent maxillary anteriors with stature and explored the possibility to estimate stature from those dimensions. In the present study population, the most common shape of face in males and females is mesoprosopic followed by euryprosopic. Our findings were similar to kumar et al's and shetti et al's studies In Andhra population, males were mesoprosopic and females – euryprosopic.[8] Priyadharshini et al. reported that the dominant face types for males and females were leptoprosopic and euryprosopic, respectively, which was completely contrary to our study.[9] The variation could be attributed to a complex interaction between genetics and environmental factors.[10] The combined mesiodistal diameter of maxillary anteriors, mesiodistal, crown length of the maxillary incisors [Figure 1] and canines of males has greater value compared to females in the present study. This can be employed as authentic anthropometric tools in gender determination. Reports by several workers from different parts of India indicate that odontometric parameters is a good tool for determining sex.[31112131415] In our study, when only the odontometric parameters regressed with height, a lesser statistically significant correlation was found. Therefore, odontometry parameters alone were unreliable in estimating stature, which is consistent with the research results of Kalia et al.[16] Jani has observed that maxillary intercanine width statistically significant correlation to stature.[17]

Bhayya et al. study predicted the height of individuals by regressing the craniometric and odontometric parameters, and it showed a great correlation.[18] The outcome of this study-derived regression equation of height of an individual is as follows:

Stature = Constant (72.203) +0.498 (facial index) +0.571 (combined mesiodistal distance of maxillary anteriors) +11.343 (gender) +1.984 (crown length of permanent maxillary left central incisor).

We checked the applicability and reliability of the regression by applying the equations in the same sample of volunteers Certain range (minimum)of difference has been observed between actual and estimated stature. This could be central tendency to formulate regressive equations. Further research in the sample populations residing in the different geographic zones is necessary for validation.

CONCLUSION

The present study demonstrates that the facial index, combined mesiodistal distance of maxillary anteriors, and maxillary left central incisor crown length for stature estimation were highly significant. It can be concluded that using regression formula is a quick and easy method for estimation of stature of an unknown individual in regional population.

Limitation

The study is conducted on Tamil population only. Therefore, studies in the same ethnic group of other parts of the world and different ethnic groups are required to confirm whether the craniofacial and odontometric dimensions can be used for estimation of stature elsewhere.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

Table 4b

Model summary

Model	R	R 2	Adjusted R2	SE of the estimate
1	0.231	0.054	0.040	8.5998

SE: Standard error