Department of legal dentistry, Cheikh Anta Diop University of Dakar, France
Submission: September 03, 2018; Published: September 14, 2018
*Corresponding author: Sankoung Soumboundou, Department of legal dentistry, Cheikh Anta Diop University of Dakar, France
How to cite this article: Sankoung S, khalifa D, Abess G, Babacar T. Applicability of “Dimodent” Sex Predictive Equation Assessed in an Senegalese
Population. J Forensic Sci & Criminal Inves 2018; 10(4): 555798. DOI: 10.19080/JFSCI.2018.10.555798.
Aims : The determination of sex is one of the most important and crucial steps in identification. Sexual dimorphism using odontometric data showed a great diversity depending on the study population, which therefore requires data specific to each population. The purpose of this study is to establish the degree of dental dimorphism within the population. A sample of Senegalese subjects using the Dimodent method described by Fronty et al 1998
Materials and Methods: A total of 104 subjects (52 males and 52 females) aged 20 to 60 years were included in this study. Mesio-distal and vestibulo diameters - linguale of the lateral incisor and the mandibular canine were measured with a digital caliper on plaster models. The measurements obtained were integrated into the sexual prediction equation
Y is evaluated based on measurements of mesiodistal and buccolingual diameters
The collected data were analyzed using Microsoft Excel version 2013.software.
The Comparison of the data was made with the Chi-square Xtests2 and Pearson and a significance level p ≤ 0.05 was retained.
Results:In this study, the overall positive prediction rate is 86.53%. The success rate was higher for men (90.38%) than for women (82.69%).
Conclusion:The method used in this study is simple and inexpensive to conduct and therefore can be applied in forensic odontology to establish an individual’s sexual identity.
In human identification the major problem faced by investigators and forensic scientists is the determination of age, sex, stature, ethnicity. Indeed in life all humans have a unique identity, even if the identical twins can present the same DNA profile preventing certain judicial investigations to succeed, but other elements like the teeth can differentiate them. The identification of living or dead people by teeth and jaws plays an important role in the forensic sciences . Thus in front of human remains or bodies in a state of advanced degradation linked to the phenomena of saponification, putrefaction or charred bodies, the determination of age and sex poses certain difficulties and is based mainly on the study of skeletal structures (oxal bone, crane sacrum) and teeth, because these structures survive for a long time after the death of an individual [1,2,3]. The determination of sex using dental characteristics is based primarily on the comparison of dental dimensions. This is based on the fact that, although the morphology of the tooth structure is similar in men and women, the size of the tooth does not necessarily remain
the same. «Sexual dimorphism» refers to differences in size, and of appearance between men and women who can be applied in dental identification.
Several studies have been conducted using canine for sex determination [4,5]. The Anderson et Thompson study  of 171 American subjects, including 83 men and 88 women aged 14 to 17 years, shows that the mesio-distal width of the mandibular canines, lateral incisors and the width of the canine bow (inter-canine distance) was greater in men than in women and allowed a correct classification of sex at 74.3%. However, after going through various databases, no study has been conducted in Senegal so far for sex determination from teeth using the mandibular canine. Given this situation, it was necessary to design the present study to determine sex using the method of Dimodent . The aim of this work was to test the applicability of the Dimodent method developed by Fronty et al on a sample of Senegalese melanoderm subjects.
This study was conducted among 104 Senegalese subjects
including (52 men and 52 women) coming to consult in the
department of odontology of the Faculty of Medicine, Pharmacy
and Odontology of the University Cheikh Anta Diop of Dakar
and in a private dental office taken at random. The institutional
authorization of the ethics committee was obtained for the
conduct of the study. Subjects were randomly selected from those
who met the following inclusion criteria.
After casting alginate (irreversible hydro-colloid) impressions
with hard plaster, the measurements were taken along the long
axis of each tooth, with a digital caliper with digital display
(Digimatic caliper, Mitutoyo, UK) of precision 0.01mm according
to the method described by Dimodent. A second measurement
was performed on 1/3 of the sample (30 models) taken at random
to evaluate intra and inter-examiner variability with another
operator to test interobserver variability. The buccolingual (VL)
and mesiodistal (MD) diameters of the canine and lower lateral
incisor were measured (Figures 1 & 2).
The Mesiodistal Dimension (MD) was defined as the largest
distance between the contact points on the proximal surfaces of
the dental crown.
The Buccolingual Dimension (VL): was defined as the
greatest distance between the buccal and lingual surfaces of the
crown perpendicular to the mesiodistal diameter of the crown of
Sexual Prediction Equation
After measurements of the mesio-distal and vestibulo-lingual
diameters of the mandibular incisors and canines, the data
were reported to the sexual prediction equation P described by
P =1/ (1+ ey)
Y is evaluated according to measurements of mesiodistal and
Y = 24.2 + (1.54* I MD) + (1.92* I VL) − (2.84* C MD) − (3,38*C VL)
MD = Mesio-distal I = Incisor
VL = Vestibulo-lingual, C = Canine
The equations and P and Y were created on Excel thanks to the
writing of the functions.
P =1/ (1+ ey)
where P expresses the probability of being in the presence of a
feminine or masculine dentition. According to Dimodent:
If P is between 50% and 100%, the teeth are probably female.
If P is between 0% and 49%, the teeth are likely to be males.
Depending on the value of P found, the samples were ranked
according to the patterns found or probability of female or male
The data collected were analyzed with the Microsoft Excel
2013 software. The quantitative variables are expressed in mean
and standard deviation and the qualitative variables in percentage
and number. The comparison of the data was made using the
Student’s test and a significance level p≤0.05 was retained.
Inter and intraobserver variabilities were evaluated with the
Kappa Cohen test.
This study included 104 Senegalese melanoderm subjects,
including 52 women and 52 men randomly selected; with an
average age of 41.22 years ± 12.58. The study of inter and intra examiner variability yielded a satisfactory kappa of 0.70. Tables
1 & 2 describe mean and standard deviations of sex-related
measurements. A statistically significant difference was found
in the median-distal p <0.0001 and vestibul-lingual P <0.0001
diameter of the canine. The measurements obtained on the lateral
incisor mesiodistal diameter are not discriminate
Sexual Prediction The overall results of this study show
a positive sexual prediction rate of 86.53% and a negative
prediction rate of 13.47%. For men, the positive prediction rate
was 90.38%, compared with 9.62% negative prediction rate. For
women, the positive prediction rate was 82.69% compared to the
17.31% negative prediction rate. The rate of sexual prediction
was higher for men (90.38%) than for women (82.69%) (Table 3).
The difference found was statistically significant p ≤ 0.05. In this
study, the Dimodent method was applicable in 86.53% of cases.
Sexual prediction was positive in 90 out of 104 people studied.
This prediction was higher for men with 90.38% (9 out of 10 men)
than for women with 82.69% (8 women out of 10).
Sex determination is one of the first steps in estimating
identification. In general, sexual identification is done using
anatomical and / or genetic parameters . However, in certain
circumstances, only bones and teeth may be the only possible
remains to provide sexual identification. Teeth have always
interested anthropologists, forensic experts, biologists because
they are the most resistant anatomical structures and still persist
where all other previous structures have disappeared. Sexual
determination by dental measurements has been the subject of
several studies [9,10,11]. The latter focused more on the mesiodistal
and vestibul-lingual diameters of certain teeth such as the
canine and incisors but especially the mandibular incisors. In this
present study, the method described by Dimodent was used. This
one focuses on the canine and the mandibular lateral incisor. This
study was conducted among 104 Senegalese subjects, Senegalese
parents and grandparents. The size of the sample (104 subjects) is
in the average found in the literature. In Lebanon, a much smaller
sample was used (60 subjects) and in India, Barthi et al worked
on a sample of 200 people including 100 men and 100 women
[12,13]. The measurements of buccolingual and mesio-distal
diameter of the canine found in men were statistically higher than
in women. For the lateral incisor, the vestibulo-lingual and mesiodistal
diameters found in men were also higher than in women,
but the difference was not statistically significant.
The same trends were found in India by Barthi et al, except
that a statistically significant difference was found between men
and women for lateral incisors. In Lebanon, too, all measurements
at the lateral incisor and at the canine level gave higher averages
for men than for women . In most studies, the measurements
of the male canine are larger than those of women. This trend has
been confirmed in this study. In comparative anatomy, canines
have always distinguished themselves from other teeth with
respect to sexual onset and dichotomy. These differences are
probably related to their function that differentiates them from
other teeth for the survival of the lineage. In carnivores and most
primates, the main function of the canines is not chewing, but is
primarily related to the threat of aggression. Thus the survival
of the species depends on the functional activity of the canines
. The results of this study corroborate evidence from other
populations that canines showed greater sexual dimorphism than
other teeth. These differences between men and women could
be related to genetic factors. It is known that the Y chromosome
is responsible for tooth size by controlling the thickness of the
dentin while the X chromosome seems to be responsible for the
modulation in enamel thickness [14,15]. Sexual differentiation may be due to more dentin in the crown of teeth in men. In this
study, the overall success rate for sexual prediction is 86.53%.
The percentage of success was higher for men (90.38%) than for
Similar earlier studies in other populations have shown
different rates. In France, the prediction rate with the same
method was 90.6%, which is almost similar to the rate found in
Senegal. In Lebanon, the predictability rate found with Dimodent
was 76.66%. In India, the predictability rate obtained was very
low; about 34% (Table 4). In this study, the predictability rate was
higher for men than for women. This same trend was found in
India, unlike in Lebanon, where the percentage was much higher
among women than among men. However, in France, according to
Fronty, out of 120 subjects the prediction rate was almost equal;
84% for men and 84.57% for women. In India, the low rate among
women (3%) compared to men (66%) led the authors to readjust
Dimodent’s formula by doing a logistic regression analysis on the
measures obtained, allowing a another formula of Y different from
that of Dimodent.
This allowed them to improve the percentage of prediction.
Thus, the overall percentage in India increased from 34.5% to
72%. In this study, the predictability rate was higher for men than
for women. This same trend was found in India, unlike in Lebanon,
where the percentage was much higher among women than
among men. However, in France, according to Fronty, out of 120
subjects the prediction rate was almost equal; 84% for men and
84.57% for women . In India, the low rate among women (3%)
compared to men (66%) led the authors to readjust Dimodent’s
formula by doing a logistic regression analysis on the measures
obtained, allowing a another formula of Y different from that of
This allowed them to improve the percentage of prediction.
So the overall percentage in India went from 34.5% to 72%, the
method used in this study has the advantage of being easy to use
because it involves only two teeth: the canine and mandibular
lateral incisor. The prediction success rate exceeds 90% in some
populations, such as Senegal, which confirms the effectiveness of
this method as a sexual determination technique. This rate could
be improved if all teeth were used, as suggested by the method of
Acharya et al which, considering all the teeth, arrived at an overall
prediction rate of almost 100% . In the rest of this work, further
studies using other complementary odontological characteristics
could improve the percentage of prediction.
The determination of sex is one of the first parameters
considered in human identification. The accuracy of sexual
diagnoses using various body parameters such as genetics, craniofacial
morphology and pubic measurements varies from 96% to
100%. In this study, the application of the odontometric method
of Dimodent produced a rather high rate of sexual prediction,
suggesting its application in sex determination.