Comparison of cheiloscopy, odontometric, and facial index for sex determination in forensic dentistry.

BACKGROUND: The "gender determination" which is an important human identification procedure not only helps in establishing the biological profile from skeletal and dental remains but also in facial reconstruction of unidentified victims. AIM: The aim of this study is to analyze predominant types of lip prints (cheiloscopy), accuracy of mandibular canine index (MCI) (odontometric), and facial index in the study population and to identify whether any correlation among the above parameters could help forensic dentistry in solving crimes.
MATERIALS AND METHODS: A pilot study was conducted in 100 individuals, 50 males and 50 females aged between 20 and 25 years. For each individual, the lip prints, MCI, and facial index measurements were recorded on the same day analyzed by two observers. All the analysis was done using SPSS version 14 assessed using t-test and Chi-square test.
RESULTS: Type II pattern of lip prints is observed as common pattern among male and female. There is no significant difference in Odontometric analysis. The mean value of facial index analysis in both genders shows highly significant.
CONCLUSION: A large-scale study is required in order to validate our results to arrive at definitive results and value.

Introduction

Forensic odontology is the science that deals with the application of dental science in the law and investigation. It not only deals with the death investigation but also it helps in evaluating the living victims of sexual assault and child abuse. The forensic odontology may help in dealing with some other domestic violence cases too. In forensic odontology, gender determination is a most important identification procedure.[123] This gender determination helps in facial reconstruction of unidentified bodies. The forensic odontology helps in determination of accuracy of various parameters that are used in sex determination.[1] The parameters that are used for sex determination are cheiloscopy, odontometric, and facial index.[245] This forensic odontology not only helps in evaluating the inter- and intra-observer variability among the three parameters but also in assessing and comparing the reliability of three parameters in sex identification.

Materials and Methods

A pilot study was done in Vinayaka Mission Sankarachariyar Dental College with 100 individuals comprising 50 males and 50 females. The age of the individuals is selected to be between 20 and 25 years. The lip prints of those individuals and their mandibular canine index (MCI) measurements and their facial index measurements are recorded and it was analyzed by the two observers and recorded.

Study design

For cheiloscopy method

The subject is requested to apply a dark-colored lipstick on the vermilion borders and it is asked to rub on both lips, and then, the records are made according to their lip prints. This lip print impression is taken as permanent record and it is visualized with the magnified lens.

On the basis of shapes and course of grooves, the lips were classified by Tsuchihashi's year of 1974 as six types.[4]

For odontometric method

Using a Vernier caliper, MCI was recorded intraorally. The mandibular canine index is calculated using the following formula,

The greatest mesiodistal width was measured between mesial and distal contact point of the right and left mandibular canine.

Mandibular intercanine width (ICW) was measured as the distance between the cusp tips of the right and left mandibular canine

Standard MCI value was obtained from the derived values for the comparative analysis using formula as:

For facial index methods

The same individuals were asked to sit in a relaxed state and straight and to look forward

The morphological facial height was measured with digital slide caliper with scale from Nasion (n) to Gnathion (gn)

Facial width: Facial width was measured as the straight distance between the right and left zygion (zy − zy)

On the basis of this index and according to the Banister's classification, the face shapes and its types were categorized.[6]

Inclusion criteria and exclusion criteria of this study are showed in Table 1.

Table 1

Inclusion Criteria and Exclusion Criteria

Results

All the analysis was done using SPSS version 11.5 (SPSS Inc., Chicago, IL). P < 0.05 was considered as statistically significant. Using “t-test,” the comparison of observer 1 and 2 and comparison between mean canine and intercanine were assessed. Using “Chi-square test,” the comparison of lip prints and facial index between males and females was done.

Lip prints analysis

According to our lip print analysis, the following results were observed. In both observer 1 and 2, Type II lip print pattern is common in males and females. In among other lip patterns the mean value of observer 1 shows highly significant P < 0.036*>. In observer 1 and observer 2, the least common lip pattern in males is Type V. No Type V pattern was observed in females.

The least common female prints in observer 1 are Type III and that in observer 2 are Type IV [Figure 1].

Figure 1

Results of lip print analysis

Odontomertic analysis

In observer 1, the mean value of males and females is highly significant (P < 0.004*) [Figure 2]. In observer 2, the mean value of males and females shows significant P < 0.006*> for the right canine index and P < 0.018*> for the left canine index [Figure 3]. There is no significant difference in mean values of males and females in observer 1 and observer 2 [Figure 4].

Figure 2

Result of inter canine width

Figure 3

Odontomertic analysis right and left canine observer 1 and 2

Figure 4

Analysis of the right mandibular canine and left mandibular canine index observer 1 and 2

Facial index

In observer 1 and observer 2, the mean of facial height and facial width of observer 1 shows highly significant P value, P < 0.001*> and P < 0.001**> respectively [Figures 5 and 6].

Figure 5

Analysis of facial height and facial width

Figure 6

Analysis facial index using Banister's classification

Discussion

Forensic dentistry plays a major role in body identification in various purposes such as criminal, legal, marital affairs, divorce, child abuse, and antisocial crimes. In personal identification, lip prints are one of the ancillary tools that can be obtained at the crime scene, from the clothing, cups, glasses, cigarette, window, and door.[27] Invisible lip prints are identified using aluminum and magnetic powder similar to finger print identification.

In our study, lip print analysis showed that in both observer 1 and 2, Type II lip print pattern is common in males and females. In other patterns, the mean value in observer 1 shows high significant P < 0.036*>. Dongarwar et al.[8] found Type IV and Type V patterns to be dominant in males and Type I pattern common in females, with complete deviation from our study. Nagalaxmi et al.[7] analyzed with two observers and the results showed that no two lip prints show a similar pattern by both observers. They observed Type I common in females and Type III common in males.

In our study, the mean ICW was 25.66 ± 1.60 in males and 24.69 ± 1.71 in females with significant P value. Mean value >6.7 mm is suggestive of males and <6.5 is suggestive of females.

Ayoub et al.[9] observed overall canine width >7.3 mm suggestive of males. Nagalaxmi et al.[7] observed that mean ICW showed higher value of 26.76 ± 1.90 in males and 25.77 ± 1.77 in females with significant P value.

The present study showed that mean of morphological facial height for females is 99.55 ± 5.83 and for males is 105.46 ± 6.26 (female values are lesser than those of males). The width of the face was greater than the height of the face. The dominant face type for males is hepatoprosopic and for females is europrosopic.[6]

Yesmin et al. (2014)[10] observed that the range of facial height in Malay females was 94.6–120.9 mm and in males it was 130.8 mm (female values are lesser than males).

Ngeow and Aljunid et al.[11] carried out a similar study on young Malaysians and found that the width of the face (males: 120–153, females: 123–142) was greater than the height of the face (males: 106.3–134.7, females: 93.9–128.9). Salve et al.[12] studied the face types of males and females as mesoprospic and eurosprospic. Praveen Kumar et al.[13] found that the dominant face type of South Indian population was hyperleptoprosopic followed by mesoprosopic which was not similar to our study.

Conclusion

In this pilot study, the results obtained from the three parameters in sex determination gave reliable significance. Our study has the uniqueness in comparing the facial index with cheiloscopy and MCI, but still, a large-scale study is required in order to validate our results.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.