A study of lip print patterns among adults of Sebha city, Libya

Cheiloscopy in sex estimation: a systematic review

This study aimed to conduct a systematic review to gather evidence to clarify if cheiloscopy can be used in sex estimation and identify the reasons behind the lack of consensus in the scientific community. The systematic review was performed following the PRISMA guidelines. A bibliographic survey was conducted in PubMed, Scopus, and Web of Science databases, restricted to articles published between 2010 and 2020. Studies were selected according to eligibility criteria, and then the study data were collected. The risk of bias in each study was assessed and applied as additional inclusion or exclusion criteria. The results of the articles eligible for analysis were synthesized using a descriptive approach. In the 41 included studies, several methodological flaws and variations between studies that contribute to the discrepancy in results were identified. The data gathered allowed us to conclude that there is no strong scientific evidence to support the use of cheiloscopy in sex estimation, as there is no specific pattern for each sex, which reduces the criminalistic interest of cheiloscopy in estimating this parameter.

The weak evidence of lip print analysis for sexual dimorphism in forensic dentistry: a systematic literature review and meta-analysis

This study aimed to assess the prevalence of lip print patterns among males and females, and to test the diagnostic accuracy of lip pattern analysis for sexual dimorphism in forensic dentistry. A systematic literature review was performed following the PRISMA guidelines. The search was performed in six primary databases and three databases to cover part of the grey literature. Observational and diagnostic accuracy studies that investigated lip print patterns through cheiloscopy for sexual dimorphism were selected. Risk of bias was assessed with the Joanna Briggs Institute (JBI) tool. Proportion meta-analysis using random effects was fitted to pool the accuracy of cheiloscopy. The odds of correctly identifying males and females was assessed through a random effects meta-analysis. GRADE approach was used to assess certainty of evidence. The search found 3,977 records, published between 1982 and 2019. Seventy-two studies fulfilled the eligibility criteria and were included in the qualitative analysis (n = 22,965 participants), and twenty-two studies were sampled for meta-analysis. Fifty studies had low risk of bias. Suzuki and Tsuchihashi's technique was the most prevalent among studies. The accuracy of sexual dimorphism through cheiloscopy ranged between 52.7 and 93.5%, while the pooled accuracy was 76.8% (95% CI = 65.8; 87.7). There was no difference between the accuracy to identify males or females (OR = 0.71; 95% CI = 0.26; 1.99). The large spectrum of studies on sexual dimorphism via cheiloscopy depicted accuracy percentage rates that rise uncertainty and concern. The unclear performance of the technique could lead to wrong forensic practice.

Characterization of lip prints in a Portuguese twins' population

Lip print patterns are referred to as unique to each individual, but controversy exists surrounding twins. In this study, the lip prints of 19 pairs of monozygotic and 47 pairs of dizygotic twins were studied. The left lower lip was photographed and the furrows were classified using Renaud's classification. Results showed the same lip pattern was found only in one monozygotic pair (5.3%) and in 4 dizygotic pairs (8.5%), and no significant statistical differences were found between groups (p > 0.05). In monozygotic twins only type C furrows presence displayed statistical significant differences (p=0.034). As for dizygotic twins, there were statistical significant differences in the frequency of type A (p=0.005) and type G furrows (p=0.018). As for the most common types, both groups displayed a higher prevalence of vertical furrows (type B: 97.4% and 96.8%, type A: 86.8% and 87.2%, in monozygotic and dizygotic, respectively). The least frequent furrow type was type I and type E in monozygotic (2.6% and 5.3%, respectively) and types E, F and I, in dizygotic (6.4%, 7.4%. and 7.4%, respectively). Our results seem to point out that lip print patterns should be useful carefully in twins' identification.

Cheiloscopy in individuals with Down syndrome and their nonsyndromic biological siblings

The study aimed to carry out a comparative analysis between the lip print patterns in individuals with Down Syndrome and their nonsyndromic biological siblings. This was a cross-sectional blind study using an inductive approach and extensive direct observation procedures. A total of 68 cheiloscopic charts, named cheilograms, were divided into two groups (n=34), as follows: G1, including Down Syndrome individuals; and G2, including their nonsyndromic siblinggs. The convenience sample was selected in the city of João Pessoa, PB, Brazil. The following features were evaluated in eight labial regions called sub-quadrants: oral commissures (downturned, horizontal and upturned); lip thickness (thin, medium, thick and mixed); and labial grooves (I - complete vertical; I '- incomplete vertical; II - bifurcated; III - criss-cross; IV - reticular; or V - undefined). The data were analyzed by paired Student's t test and McNemar's Chi-square, with a 5% significance level. Most Down Syndrome individuals were found to have downturned oral commissures in 73.5% of cases, while their siblings showed a predominance of horizontal commissures in 73.5% of cases (p=0.009). There was no statistically significant difference for lip thickness between groups. In the analysis of labial groove patterns, Down Syndrome individuals (G1) showed a significant prevalence of the type I pattern (52.2%) as compared to their nonsyndromic siblings (30.1%) (p =< 0.001). Due to the tendency of having vertical labial groove patterns and downturned commissures, Down Syndrome individuals present cheiloscopic differences in relation to their nonsyndromic biological siblings, which suggests that syndromic genetics influences the development of these features. However, this may imply in a reduced potential of cheiloscopic identification due to the low divergence of labial phenotypes among Down Syndrome individuals.

Lip print identification: Current perspectives

Lip print identification has been proposed as an additional tool for crime investigation because of the supposed uniqueness of labial grooves; however, critics of the validity and reliability for methods and techniques redefined standards and requirements in order to consider this discipline a real forensic identification science. During our research we identified recent literature, presented here, which although extensive, have focused almost entirely on anthropological topics with outdated references which were not from primary sources and, furthermore, were erroneously quoted. Currently, authors continue to use the concept of lip pattern uniqueness, yet the greatest part of their research has failed to support this hypothesis under current scientific standards. Concepts and designs needed to evaluate materials for lip print development - the isolation of DNA, evaluation of inter-rater reliability in identifying their patterns or known potential rate of error - are scarcely mentioned in the reviewed literature. Lip print identification has been important historically, but the new paradigm makes the redefinition of the current research necessary to stop guesswork and speculation.

Regression equations for sex and population detection using the lip print pattern among Egyptian and Malaysian adult

INTRODUCTION

Identification of sex and ethnicity has always been a challenge in the fields of forensic medicine and criminal investigations. Fingerprinting and DNA comparisons are probably the most common techniques used in this context. However, since they cannot always be used, it is necessary to apply different and less known techniques such as lip prints.

AIM OF THE WORK

Is to study the pattern of lip print in Egyptian and Malaysian populations and its relation to sex and populations difference. Also, to develop equations for sex and populations detection using lip print pattern by different populations (Egyptian and Malaysian).

SUBJECTS AND METHODS

The sample comprised of 120 adults volunteers divided into two ethnic groups; sixty adult Egyptians (30 males and 30 females) and sixty adult Malaysians (30 males and 30 females). The lip prints were collected on a white paper. Each lip print was divided into four compartments and were classified and scored according to Suzuki and Tsuchihashi classification. Data were statistically analyzed.

RESULTS

The results showed that type III lip print pattern (intersected grooves) was the predominant type in both the Egyptian and Malaysian populations. Type II and III were the most frequent in Egyptian males (28.3% each), while in Egyptian females type III pattern was predominant (46.7%). As regards Malaysian males, type III lip print pattern was the predominant one (41.7%), while type II lip print pattern was predominant (30.8%) in Malaysian females. Statistical analysis of different quadrants showed significant differences between males and females in the Egyptian population in the third and fourth quadrants. On the other hand, significant differences were detected only in the second quadrant between Malaysian males and females. Also, a statistically significant difference was present in the second quadrant between Egyptian and Malaysian males. Using the regression analysis, four regression equations were obtained.