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Background: The importance of continuous monitoring along with rapid and accurate notification of changes in blood components such as hemoglobin concentration, especially in acute situations, encourages researchers to use non-invasive methods for measuring.Objective: This study was aimed to investigate the correlation between hemoglobin concentration and photoplethysmogram (PPG) and the possibility of measuring it by an optical method.Material and Methods: In this applied study, a PPG signal was simultaneously recorded at four different wavelengths for thirty subjects who were referred to the laboratory for a hemoglobin concentration test. After calibrating the special recording probe with a standard pulse oximeter system and applying the required preprocessing on the obtained signals, the peak-to-peak value of PPG signals was extracted. Finally, the correlation between the peak-to-peak value of the signal at a certain wavelength and hemoglobin concentration was analyzed using Spearman and Pearson correlation for determining the process of changes in the data.Results: The results demonstrated that based on the normal distribution of data at 590 nm wavelength, there is a significantly negative correlation between a function of the signal peak slope and the hemoglobin concentration, with a Pearson coefficient of -0.787 (p<0.01). In addition, the investigation of rank correlation indicated a significantly negative correlation of -0.842 (p<0.01) using Spearman correlation analysis.Conclusion: Considering the high correlation between hemoglobin concentration and PPG signal characteristics, optical methods can be used to develop a rapid, precise, clean and inexpensive method to measure hemoglobin concentration.

The role of forensic odontology has increased in recent years. Age estimation of living or deceased individuals is an important aspect of this science .Dental age estimation methods are of particular value because teeth are highly resistant to mechanical, chemical, or physical impacts and time. So the aim of this study was to investigate the possible estimation of age by using dental age through some dental measurements using cone beam computerized tomography (CBCT). The study was done on forty eight cases (24 males and 24 females). Multiple measurements were done on the right upper central incisor, right upper lateral incisors, right upper canine and right first premolar teeth and their pulp at different levels (maximum width of the crown, cervical area, mid-root and apex) by many views: sagittal (buccolingual dimension), coronal (mesiodistal dimension), and axial (bucco-lingual and mesiodistal dimensions). In addition the tooth and the pulp areas were measured .The study proved that the most accurate model for determination of age in upper first premolar tooth was measurement of pulp length + pulp width at the crown+ pulp width mid level of the pulp where R was 97%. Followed by upper central incisor pulp width at mid-level of the pulp in Bucco-lingual view with R 96%. While measurement of tooth length for upper canine at Bucco-lingual view was the least accurate method for this tooth with R 90%. So the study concluded that using CBCT is useful in detection of age by obtaining linear teeth measurements. In addition, the use of the upper first premolar tooth measurements followed by upper central incisor followed by upper canine are useful in estimating the chronologic age of any person.