Mandibular Canine Index (MCI)
Definition
The ratio of mandibular canine mesiodistal crown width to intercanine distance, multiplied by 100. Values above a population-specific threshold lean male. Described by Rao et al. (1989) and the most cited single-tooth metric for sex estimation.
- Formula
- Mesiodistal canine width / intercanine distance x 100
- Use
- Sex estimation from a single tooth
- Threshold
- Population-specific, higher values lean male
- Source
- Described by Rao et al., 1989
Common questions
Why does the MCI need a population-specific threshold rather than one universal cutoff?+
Tooth size and sexual dimorphism vary between population groups, so a threshold derived from one population can misclassify individuals from another; forensic odontologists calibrate the cutoff against a reference sample matched to the case population before applying it.
Why is a single-tooth metric like the MCI useful when other skeletal indicators are available?+
Teeth resist decomposition and survive fire, dismemberment, and long post-mortem intervals far better than the pelvis or skull that give more reliable sex estimates, so the MCI provides a usable estimate when only dental remains are recovered.
Related terms
- Amelogenin
- A gene on both the X and Y chromosomes used for sex determination in forensic STR kits. The X-allele amplicon is approximately...
- Barr Body
- A condensed, transcriptionally inactive X chromosome visible in the interphase nuclei of XX individuals. In dental cells it appears as a small...
- Discriminant Function Analysis (DFA)
- A multivariate statistical method that builds a weighted linear equation from measurements to classify specimens into groups (here, male or female). A...
- Odontometrics
- The quantitative measurement of teeth, covering crown diameters, root lengths, and cusp dimensions. In forensic practice these measurements feed discriminant function analyses...
- Sexual Dimorphism
- Systematic physical differences between biological males and females of a species. In teeth it is expressed mainly as size: males average larger...