Secondary dentine deposition is responsible for the decrease in the volume of the pulp cavity with age. Therefore, the volume of the pulp cavity can be considered as a predictor for estimating age. The aims of this study were to investigate the relationship strength between canine pulp volumes and chronological age from homogenous (approximately equal numbers of individuals in each age range) age distribution and to assess the effect of sex as predictor in age estimation. This study was performed on 719 subjects of Pakistani origin. Cone beam computed tomography images of 521 left maxillary and 681 left mandibular canines were collected from 368 females and 349 males aged from 15 to 65 years. Planmeca Romexis® software was used to trace the outline of the pulp cavity and to calculate pulp volumes. Regression analysis was performed to assess the correlation between pulp volumes considering with and without sex as a predictor with chronological age. The obtained results showed that mandibular canine pulp volume and sex have the highest predictive power (R2 = 0.33). The relationship between mandibular canine pulp volume and sex with chronological age demonstrates an odd S-shaped non-linear relationship. A statistically significant difference in volumes of pulp was found (p = 0.000) between males and females. The conclusion was that predictions using the pulp volume of the mandibular canine and sex produced the best estimates of chronological age.Electronic supplementary materialThe online version of this article (10.1007/s00414-019-02147-5) contains supplementary material, which is available to authorized users.

Radiographic methods using pulp tooth volume ratio (PTVR) are important for dental age estimation. According to previous studies, using PTVR possess different relationships with age in males and females but none of the studies have used a homogenous (approximately equal numbers of individuals in each age range) age distribution to assess this relationship and the effect of sex as predictor on age estimation.This study was performed on Cone beam computed tomography images of 521 left maxillary and 681 left mandibular canines of 719 subjects of Pakistani origin (368 females and 349 males) aged from 15-65 years. Planmeca Romexis® software was used to trace the outline of the pulp cavity and tooth and to calculate respective volumes. Subsequently, Microsoft®Office Excel 2016 was used to calculate the ratios.Regression analysis was performed to assess the relationship between PTVR factoring sex in as a predictor for age estimation. The obtained results showed that including sex as predictor with maxillary PTVR (R 2 =0.46) have the highest predictive power. The relationship between maxillary PTVR including sex with chronological age demonstrates a non-linear relationship.The conclusion is that including sex as predictor with maxillary PTVR produced the best estimate of chronological age.

The protocol was published at DOI: 10.1186/1745-6215-15-389.

The properties of the skin and the posture of the body during photographic recording are factors that cause distortion in the bite mark injury. This study aimed to explore the degree of distortion between a 'touch mark' (method 1) and a 'bite mark' (method 2) on the left upper arm at three different positions (arm relaxed; arm flexed in two different positions). A pair of dental casts with biting edges coated in ink was used to create a mark in 30 subjects (6 ♂, 24 ♀) aged 20-50 years old. Photographs were taken using a Nikon DX digital camera (D5000). The mesiodistal widths and angle of rotations of both upper right central incisor and lower right central incisor and the inter-canine distances were analysed and compared with the true measurements using Adobe Photoshop CC 2017. Statistical analysis was carried out using SPSS Statistics 22 applying a 2 (mark type) × 3 (position) repeated measures ANOVA. For all measures studied, there was a statistically significant difference between mark types and positions. In the case of bite marks, a great degree of distortion was detected, and this increased further when changing the position of the arm. The findings demonstrated that skin properties and posture influence distortion. This could lead to inaccurate measurements and misleading pattern interpretation of bite mark injuries.

The trial was registered with ClinicalTrials.gov on 5 March 2014, registration number: NCT02080338.

We investigated the mental rehearsal of complex action instructions by recording spontaneous eye movements of healthy adults as they looked at objects on a monitor. Participants heard consecutive instructions, each of the form "move [object] to [location]". Instructions were only to be executed after a go signal, by manipulating all objects successively with a mouse. Participants re-inspected previously mentioned objects already while listening to further instructions. This rehearsal behavior broke down after 4 instructions, coincident with participants' instruction span, as determined from subsequent execution accuracy. These results suggest that spontaneous eye movements while listening to instructions predict their successful execution.

Introduction: Discrepancy of the upper dental midline to the facial midline plays an important role in smile aesthetic assessment. This study presents different reference points to quantify the deviation of upper dental midline to the facial midline in 2D frontal photographs. The aim was to find the most accurate, precise, and practical reference points to measure dental midline discrepancy in 2D photographs.Methodology: A modified headset with a protractor was developed in order to achieve photographs in nine standardised head positions. Six reference points were used to detect the facial midline in the 2D photographs (eyebrows "EB", innercanthus of the eyes "ICE", alae of the nose "AN", columella "C", nasolabial folds "NLF", and the philtrum "PH"). The deviation of the maxillary dental midline from the facial midline was measured and compared with clinical measurements. Statistical analysis: Standard deviations (SD), Root Mean Square Error (RMSE), Method of Moments' Estimator (MME), 2-way repeated measures ANOVA, and multi-level linear model were used to estimate the true errors. Results:The different reference points responded significantly differently to changes in head position and all showed measurement errors, which increased with greater head rotation. Alae of the nose showed the least measurement error and the greatest precision in all head positions. Conclusion:The alae of the nose are the recommended reference points to identify the facial midline in order to quantify dental midline deviation from frontal photographs.

The protocol was published at DOI: 10.1186/1745-6215-15-389.