Mouth width prediction in craniofacial identification: cadaver tests of four recent methods, including two techniques for edentulous skulls

An understanding of the structural relationships between the soft tissue anatomy of the face and the hard tissue anatomy of the skull is significant for craniofacial identification methods employed in forensic anthropology and forensic dentistry. Typically, mouth characteristics have been predicted from the teeth but this proves problematic in edentulous skulls. Some clue may, however, be provided by non-dental features. This study investigates the usefulness of the infraorbital and the mental foramen position for determining mouth width and additionally reports on accuracy tests using two other recently proposed methods that depend on the teeth: i) Krogman and İşcan's radiating mouth width prediction guideline; and ii) Stephan and Henneberg's 75% rule. Dissections of nine human cadavers indicate that the most accurate mouth width prediction method is the 75% rule (mean error of -2.4mm) followed by the distance between the infraorbital foramen (mean error of -3.3mm). Krogman and İşcan's radiating method, as interpreted by Wilkinson, underestimated mouth width by 7.3mm on average, while the distance between the mental foramen underestimated mouth width by 12.9mm. These results suggest that the infraorbital foramen can be used as a relatively good predictor of mouth width in edentulous skulls, however, the 75% rule should be given precedence if the dentition is present