Comparative study of sex estimates in adult skulls using direct measurement and tomographic image reconstruction

Abstract Sex estimation is an important procedure in forensic anthropology for human identification. The development of new technologies, such as three-dimensional computed tomography (CT), has provided excellent alternatives for this purpose. This study examined and compared a morphological method for sex estimation using two different approaches - direct measurement of physical structures and tomographic analysis using 3D images. A total of 111 skulls from the Museum of Human Anatomy at the University of São Paulo (MAH-USP) were used, (60 males and 51 females). All specimens were scanned by Philips Brilliance 64 CT scanner equipment and their corresponding images were reconstructed in three-dimensional (3D) models. The morphological characteristics of the skulls were analyzed by an observer who was blinded to the sex of the specimens. Five cranial structures were analyzed: external occipital crest, mastoid process, supraorbital margin, glabella, and mental eminence. The structures were scored 1 to 5 according to Buikstra and Ubelaker and validated by Walker. The success rates of the sex estimates obtained through direct measurement of the dry skulls ranged from 67.4% to 70.4% as compared to 60.2% to 68.1% for CT reconstruction. When analyzed separately, the maximum accuracy of the method was 68.33% in males and 88.24% in females in the physical analysis of structures. The glabella and mastoid process were the most effective structures to estimate sex through both techniques, respectively. Our results show that 3D CT images can be accurately used in the morphological analysis for sex estimation, representing a viable alternative in forensic anthropology.

Porosity, residual monomer and water sorption of conventional heat-cured, microwave-cured and cross-linked acrylic resins

This study compared the residual monomer release, water sorption and superfi cial porosity of different resins commonly employed in eye prostheses: heat-cured (HC); microwave-cured (MC) and self-curing cross-linked acrylic resins (SC). Four groups were established: G1, HC / water bath cycle; G2, MC / microwave cycle; G3, HC / microwave cycle; G4, SC. The amount of residual monomer was similar in G1 and G3, lower in G2 and higher in G4. Water sorption was similar in all groups. G2 showed more superfi cial porosity, and G1 and G3 were similar in this regard. Neither the conventional heat-curing cycle nor the microwave cycle affected the amount of residual monomer or porosity of the conventional heat-cured acrylic resin. Water sorption was not affected by the type of resin or polymerization cycle used. Residual monomer release and porosity were related to the type of resin employed rather than the polymerization cycle they were submitted to.