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

Abstract

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.

Forensic Dentistry as an Analysis Tool for Sex Estimation: A Review of Current Techniques

“…Furthermore, the studies have limited sample sizes (understandably because these studies were difficult to conduct), [59][60][61] and Franco et al found that most of the studies on cheiloscopy were highly heterogenous, generally observational and cross-sectional with a lack of standardisation in methodology, which could have incorporated greater error into the findings. 57 The pooled accuracy was 76.8% and the authors concluded that cheiloscopy is not a reliable tool in forensic practice for sex estimation. 57 In forensic practice, cheiloscopy involves obtaining a lip print from the individual and then comparing the print to a known source.…”

“…57 The pooled accuracy was 76.8% and the authors concluded that cheiloscopy is not a reliable tool in forensic practice for sex estimation. 57 In forensic practice, cheiloscopy involves obtaining a lip print from the individual and then comparing the print to a known source. One major disadvantage of using lip prints for sex estimation in dental profiling is that the usefulness of cheiloscopy heavily depends on the lips being intact at the time of post-mortem examination.…”

“…Lip prints were found to be unique amongst individuals and the analysis of lip prints and patterns is a technique that could facilitate forensic human identification. 56 In a systematic review and meta-analysis done by Franco et al, it was found that the most prevalent classification used in cheiloscopy studies is the Suzuki and Tsuchihashi (1970) classification, 57 which classifies lip patterns into five distinct categories.…”

Global bibliometric mapping of dental development research for the period 2012–2021

“…Dental evidence has been studied for several forensic purposes over the years. Expect human identification, bite mark analysis, 20 anthropological estimation of age, 21 sex, 22 stature, 23 and ancestry, 24 rugoscopy, 25 and cheiloscopy 26 currently represent fields of forensic odontology 27 . (b) Tooth development results from the epithelial‐mesenchymal interaction, and tooth development consists of three parts: bud stage, cap stage, and bell stage 28,29 .…”

“…Expect human identification, bite mark analysis, 20 anthropological estimation of age, 21 sex, 22 stature, 23 and ancestry, 24 rugoscopy, 25 and cheiloscopy 26 currently represent fields of forensic odontology. 27 (b) Tooth development results from the epithelial-mesenchymal interaction, and tooth development consists of three parts: bud stage, cap stage, and bell stage. 28,29 Odontoblast secretes noncollagenous proteins, including dentin sialophosphoprotein (DSPP) and dentin matrix protein 1 (DMP1).…”