A new age estimation procedure based on the 3D CBCT study of the pulp cavity and hard tissues of the teeth for forensic purposes: A pilot study

BackgroundDental age of adults can be estimated by the analysis of the progressive physiological and degenerative phenomena which affect dental tissues. The pulp-dentinal complex is one of the dental structures that show modifications related to age, mainly resulting in the reduction of the pulp chamber volume due to the continual deposition of secondary dentin. The study aims to evaluate the accuracy of a simple and conservative method for estimating the age of adults based on CBCT (Cone Beam Computed Tomography) analysis of the narrowing of the pulp chamber caused by secondary dentin deposition.Materials and methodsTwo operators have randomly analyzed 148 CBCT (Scanora 3D – Soredex) and considered the upper left central incisor. The sample consists of 57 male individuals and 91 females aged between 10 and 80 years. This research was designed to simplify dental volume measurement through geometric approximation of the different parts of the tooth. The root and the pulp were assimilated to elliptical based cones and the crown to an elliptical based truncated cone and these volumes were calculated through measurements using Osirix^® software (OnDemand 3D software CyberMed Inc.). The ratio between the pulp volume and the hard tissues volume (PHr) was assumed as a variable according to the following formula: PHr = V pulp/V ht. The proposed method based on geometric approximation of dental volumes was validated comparing volumes calculated using CBCT with physical measurements of real volumes of 3 teeth.ResultsThe physical measurements revealed that the measurement procedures using CBCT produce a regular underestimation of real volumes, that ranges from 53% to 70%. Since the error occurs quite regularly both for pulp and for hard tissue volume, it tends to be eliminated when their ratio is considered. The PHr was statistically significant (p-value < 0.001) as a predictor for age estimation. The gender variable was not significantly correlated with age (p = 0.7694) and it was, therefore, excluded from the linear regression formula for age estimation: Age = −64.14 – 32.00*Ln PHr. The age cohorts between 30 to 59 years showed the highest accuracy in age prediction (residual errors 0.71, 2.88, and −5.86 years), whilst for other age cohorts the estimation error is similarly reported by applying other dental methods.ConclusionThe outcomes of this pilot study show that the narrowing of the pulp chamber is a reliable parameter for estimating the age of adults, and that CBCT is an easy and conservative approach that allows accurate calculation of tooth volumes. The proposed approach based on geometric approximation of upper central incisor volumes measured by CBCT remarkably reduced the operating time in comparison to other more complex and expensive techniques. The validation procedure in which real volumes are compared with those calculated using CBCT supports the accuracy of the experimented approach and the good inter-examiner agreement (ICC 0.99) demonstrates that the method is highly reproducible.     

The applicability of Kvaal methods and pulp/tooth volume ratio for age estimation of the Turkish adult population on cone beam computed tomography images

The contraction of the pulp chamber with secondary dentin apposition is a significant morphological dental age predictor in adults. The aim of this study is to evaluate the applicability of Kvaal’s method and pulp/tooth volume ratio on cone-beam computed tomography (CBCT) images and develop a valid method for the Turkish adult population. In this study, 211 single-rooted teeth, extracted for orthodontic and periodontal reasons, of 134 patients with ages ranging from 16 to 71 years, were used. Each sample was scanned using CBCT. According to the reported technique (Kvaal’s method), teeth were analysed on CBCT images. Additionally, pulp/tooth volume ratio was calculated using ITK-SNAP 3.4.0 software. The relationship between age and morphological variables was calculated by the Pearson correlation coefficient. Multiple linear regression models were established for each tooth, age as dependent variable, and morphological variables as independent variables. The determination of coefficients of the Kvaal’s modified regression models were found in a range from 0.296 to 0.550. The pulp volume and the pulp/tooth volume ratio showed statistically significant differences between age groups (p < 0,001). Pulp volume and pulp/tooth volume ratio is a significant index for age. Linear measurement and ratios on CBCT images were insufficient estimates of the age of the Turkish population.     

Overcoming population differences for dental age estimation in adults through pulp/tooth volume calculations: a pilot study

ABSTRACT

The aim of this pilot study is to explore the possibility of developing a method for dental age estimation in adults, regardless of their nationality or ethnic background, by reconstructing only a fraction of the tooth, generating linear regression models and an equation for age estimation. Eighty-one anonymized cone beam computed tomography images obtained from two different population groups were used. Only sex and age information was known. One group had a Latin-American background (Colombian individuals aged 23 to 71 years) and the other had an Asian background (Malaysian individuals aged 15 to 58 years) The analysed tooth was the maxillary canine, on which was done automatic volume reconstruction of the cervical third of root and root canal. Sample analysis showed that the ages were unequally distributed in the two groups, but by combining them a more equal age distribution was obtained. The correlation coefficient between pulp/pulp+tooth volume ratio increased when data from individuals of both populations were included in the same statistical analysis (R ² = 0.42). It has been established that methods for age estimation must be population specific. This study presents an analysis including data from individuals that are ethnically different and geographically separated, obtaining promising results.     

Dental age estimation in Malaysian adults based on volumetric analysis of pulp/tooth ratio using CBCT data

Forensic odontology plays an important role in human identification and dental age estimation is an integral part of this process. The aim of the study was to investigate the association between chronological age and pulp/tooth volume ratio in a Malaysian population (Malays and Chinese) from cone-beam computed tomography (CBCT) scans, enhanced with Mimics software. Three hundred CBCT scans of 153 males and 147 females, aged between 16 and 65 years were divided into 5 age groups. Volumetric analysis of the pulp/tooth ratio was performed in maxillary left canines, maxillary right canines and maxillary right central incisors. Simple linear regression and Pearson correlation analysis indicated the strongest coefficient of correlation (R) values for maxillary right central incisors (0.83) followed by maxillary right canines (0.74) and maxillary left canines (0.73). Fisher’s Z test indicated that dental age estimation is gender independent. The derived regression equations were further validated on an independent group of 126 teeth. The results indicated mean absolute error (MAE) values of 6.48 and 8.58 years for maxillary right central incisors and maxillary canines respectively. It was also noticed that MAE values were higher among the age groups ranging from 46 to 65 years. This study showed that a volumetric change in the pulp cavity with age is a valuable assessment method for dental age estimation among Malaysian population.     

Quantification of secondary dentine formation from orthopantomograms—a contribution to forensic age estimation methods in adults

The accuracy of most age determination methods in adults is unsatisfactory and therefore more precise methods are required. Teeth provide several useful points about an individuals age. With advancing age secondary dentine is deposited along the wall of the dental pulp chamber leading to a reduction in the size of the pulp cavity. These age-related changes can be determined and measured from dental radiographs. The aim of this study was to explore if measurements of the size of the pulp cavity performed on orthopantomograms can be used for individual age estimation. Measurements were made digitally for 6 types of teeth from orthopantomograms of 168 individuals aged between 14 and 81 years old. To compensate for errors due to the technique of radiography—for instance differences in angulation—ratios of distances were calculated: pulp/root length, pulp/tooth length and pulp/root width at three different root levels. The width ratios of the pulp cavity showed significant correlation to the chronological age and the coefficient of determination (r²) was highest in the upper lateral incisors (r²=0.913) when an exponential or a logistic regression model was constructed. At the same distance with a linear regression model the coefficient of determination (r²) reached 0.839.     

Age estimation from pulp/tooth area ratio in maxillary incisors among Egyptians using dental radiographic images

Age estimation from dental radiographs is a non-destructive, simple method to obtain information. The aim of this study was to determine the reliability of age estimation from Egyptians' incisors radiographs. 144 periapical radiographs of maxillary (central & lateral) incisors (both sexes) aged 12-60 were used. Digital camera was used to image the radiographs. Images were computed and pulp/tooth area ratios were determined by AutoCAD Program. Data were subjected to correlation and regression analysis which showed statistically significant correlation (r?=?0.23 &P?=?0.006 for maxillary central incisors and r?=?-0.2 &P?=?0.05 for maxillary lateral incisors) between age and pulp tooth area ratio. Linear regression equations were determined separately for both central and lateral incisors along with the corresponding Standard Error of Estimate, which ranged from 1.2 to 5.08 years. Consequently, it was concluded that pulp/tooth area ratios of incisors are reliable for estimation of age among Egyptians in forensic work.     

Age estimation by pulp/tooth ratio in lateral and central incisors by peri-apical X-ray

Since 2004, several papers on the analysis of the apposition of secondary dentine have been published. The aim of this paper was to study a sample of peri-apical X-ray images of upper and lower incisors, both lateral and medial, to examine the application of pulp/tooth area ratio as an indicator of age. A sample of 116 individuals, 62 men and 54 women, aged between 18 and 74 years, was studied. Data were fitted with age as a linear function of the pulp/tooth ratio of incisors. The total variance explained by the regression equation ranged from 51.3% of age, when lower lateral incisors were used as explanatory variable, to 81.6% when upper lateral incisors were used. The accuracy of the corresponding regression model yielded ME = 8.44 and 5.34 years, respectively. These results show that, although incisors are less reliable than canines or lower premolars, they can be used to estimate age-at-death when the latter are absent.     

Relationship of Antenna Work and Ablation Cavity Volume Following Percutaneous Microwave Ablation of Hepatic Tumors

PurposeTo formulate a statistical model relating ablation time, power, and work with posttreatment cavity volume following percutaneous microwave ablation of hepatic tumors in vivo.Materials and MethodsA retrospective review (October 2015 to October 2018) yielded 122 hepatic tumors treated with microwave ablation. Ablation cavity dimensions were measured at 1-month follow-up examination and calculated using an ellipsoid volume formula. The antenna manufacturer (Neuwave Medical, Madison, Wisconsin) provided the activation time and energy used to calculate the antenna work. Generalized estimating equations with ordinary least-squares regression models were obtained to relate tumor volume with cumulative antenna work. Coefficient of determination (R²) and mean square error were used as statistical measures of model prediction performance.ResultsThere is a logarithmic relationship between postablation cavity volume (cm³) and cumulative work (kJ), represented by the formula: log₁₀ cm³ = ?0.4583 + 0.9887 × cumulative work (log10 kJ) (R² = 0.41, mean square error, 0.102). Ablation volumes were predicted as a function of antenna work, calculated using an antilog transformation. When a single antenna was used, ablation cavity volume was predicted using a generalized estimating equation ordinary least-squares regression model of power and time: log₁₀cm³= ?0.0546 + 0.0485 × total time (min) + 0.0107 × power (W) (R² = 0.30; mean square error, 0.106). Using this model, a nomogram was developed to predict the postablation cavity volume based on total activation time and target power.ConclusionThere is a logarithmic relationship between the ablation work and posttreatment ablation cavity volume, which can be expressed in a nomogram when using a single probe.     

Novel laser activated photoacoustic streaming for removing pulp remnants from round root canals after single file reciprocating instrumentation

Background: This study evaluated the efficacy of a new laser-assisted irrigation system, the shock wave enhanced emission photo-acoustic streaming (SWEEPS) technique in removing pulp tissue from single-rooted premolars.Methods: Freshly extracted mandibular premolars with round root canals (n = 40), scanned using cone beam computed tomography, were randomly divided into control and four experimental (according to the irrigation technique used) groups (n = 8/group). Groups 1, 2, and 3 were instrumented using Reciproc Blue (RB25/0.06) followed by final irrigation protocol (FIP), activated by SWEEPS, ultrasonically activated irrigation (UAI), and conventional irrigation (CI), respectively. In these groups, 7 mL 3% NaOCl in total was used during instrumentation; for FIP, 3% NaOCl (60 s), ethylenediaminotetraacetic acid (60 s), and 3% NaOCl (30 s). In group 4, SWEEPS activation of 3% NaOCl for 6 × 30 s alone was performed. The untreated control group specimens were processed for histological evaluation of remaining pulp tissue (RPT) in each canal third. The results were analyzed using the Mann-Whitney U test (α = 0.05).Results: Significant differences were observed between the control group and the experimental groups (p<0.05). In the middle third, the UIA and SWEEPS showed similar efficacy (p = 0.171), superior to CI and SWEEPS without instrumentation (p<0.05). In the apical third, SWEEPS was the most efficient (p = 0.002), and UIA and CI showed no difference (p = 0.643).Conclusion: SWEEPS was superior to UIA and CI in removing RPT in the apical region of round canals after single instrument root canal preparation; SWEEPS without instrumentation was inefficient in removing pulp tissue.     

Applicability of pulp/tooth ratio method for age estimation

The purpose of this study was to evaluate the reliability of the tooth/pulp ratio method in the process of age estimation at the moment of death in a forensic context and compare it with standard anthropological methods. After the exhumation of mass graves located in sites in Batajnica, Serbia, in 2002 and 2003, skeletal material was thoroughly analyzed by a group of anthropologists and pathologists. As a part of the investigation, orthopantomography (OPG) was performed for each individual. During 2018 these OPGs were reexamined for scientific purposes. Age-at-death was assessed by means of the pulp/tooth ratio method applied to all available lower premolars. Estimated age following standard anthropological methods and chronological age (obtained after DNA identification of victims) was taken from the records. Age estimation using the pulp/tooth ratio and standard methods was compared with chronological age. The pulp/tooth ratio method was accurate in 81.25% of all cases and the standard method was accurate in 56.25% of all cases. The pulp/tooth ratio method of age estimation was found to be applicable and accurate. However, age estimation should be based on all available methods.     

Age determination of adult individuals by three-dimensional modelling of canines

Accurate age determination is fundamental in both forensic medicine and anthropology. Many methods that relate dental characteristics to adult age have been proposed, but there is still no simple and reliable method that does not damage the study material. The aim of this work was to propose a relevant and practical technique for determining age in adults that could be used in both living and deceased individuals. The sample was composed of 210 CT scans from individuals aged from 15 to 85 years old, with four healthy canines present in the mouth. The 840 canines were modelled using Mimics® 10.01 software. The pulp volume/total volume ratio ×100 was determined for each tooth. Seven mathematical models, corresponding to all possible real situations, were determined by the weighted least squares method and ranked in order of relative performance. The adequacy of the seven models to the data was very high with the regressions proposed (0.915?<?R ² _adjusted?<?0.964). Ranked in order of performance, the maxillary model was the most powerful of the seven models for age determination, followed by the 4 canines model, the 13 model and the 23 model.     

Coronary volume to left ventricular mass ratio in patients with diabetes mellitus

BackgroundDiabetes mellitus is a major risk factor for coronary artery disease (CAD) and may provoke structural and functional changes in coronary vasculature. The coronary volume to left ventricular mass (V/M) ratio is a new anatomical parameter capable of revealing a potential physiological imbalance between coronary vasculature and myocardial mass. The aim of this study was to examine the V/M derived from coronary computed tomography angiography (CCTA) in patients with diabetes.MethodsPatients with clinically suspected CAD enrolled in the ADVANCE (Assessing Diagnostic Value of Non-invasive FFRCT in Coronary Care) registry and known diabetic status were included. Coronary artery volume and left ventricular myocardial mass were analyzed from CCTA and the V/M ratio was calculated and compared between patients with and without diabetes.ResultsOf the 3053 patients (age 66 ?± ?10 years; 66% male) with known diabetic status, diabetes was present in 21.9%. Coronary volume was lower in patients with diabetes compared to those without diabetes (2850 ?± ?940 ?mm³ vs. 3040 ?± ?970 ?mm³, p ?< ?0.0001), whereas the myocardial mass was comparable between the 2 groups (122 ?± ?33 ?g vs. 122 ?± ?32 ?g, p ?= ?0.70). The V/M ratio was significantly lower in patients with diabetes (23.9 ?± ?6.8 ?mm³/g vs. 25.7 ?± ?7.5 ?mm³/g, p ?< ?0.0001). Among subjects with obstructive CAD (n ?= ?2191, 24.0% diabetics) and non-obstructive CAD (16.7% diabetics), the V/M ratio was significantly lower in patients with diabetes compared to those without (23.4 ?± ?6.7 ?mm³/g vs. 25.0 ?± ?7.3 ?mm³/g, p ?< ?0.0001 and 25.6 ?± ?6.9 ?mm³/g vs. 27.3 ?± ?7.6 ?mm³/g, respectively, p ?= ?0.006).ConclusionThe V/M ratio was significantly lower in patients with diabetes compared to non-diabetics, even after correcting for obstructive coronary stenosis. The clinical value of the reduced V/M ratio in diabetic patients needs further investigation.     

Quantification of epi- and pericardial adipose tissue deposits between males and females during cardiac CT may potentially help categorize coronary artery disease risk with thoracic circumference

IntroductionThis study aims to investigate the association between epi- and pericardial adipose tissue deposits around the heart against patient body habitus when using cardiac computed tomography (CT).MethodsNinety-two consecutive patients with suspected coronary artery disease underwent coronary CT angiography with quantitative cardiac and adipose tissue volume measurements. Body mass index (BMI), body surface area (BSA), thoracic circumference, anteroposterior diameter, cardiac and adipose tissue volumes were compared between genders by employing Pearson's correlation and results were considered statistically significant if p ≤ 0.05.ResultsStatistically significant differences between genders were observed with males having a greater height (males 1.72 ± 0.11), BMI (30.76 ± 7.87 kg/m²), BSA (2.06 ± 0.21 m²), thoracic circumference (1022.12 ± 97.90 mm²), and pericardial adipose tissue volume (46.72 ± 36.62 mm³) (p < 0.05). For men, for Group 1 (BMI ≤ 27) each of the measured volumes showed moderate correlation between pericardial adipose tissue and AP chest-diameter (r = 0.429, p < 0.05), whereas in Group 2 (27 < BMI ≤ 31.1), coronary artery volume had a strong association with the AP chest-diameter (r = 0.453, p < 0.05).ConclusionBMI and thoracic circumference are closely related to variable epi- and pericardial adipose tissue volumes in both males and females during cardiac CT.Implications for practiceQuantification of epi- and pericardial adipose tissue deposits between males and females during cardiac CT may help further categorise coronary artery disease risk when including BMI and thoracic circumference for males and females.     

Development of formulae for dental age estimation using digital radiographs in the Mongolian population

This study aimed to examine the applicability of the pulp/tooth ratio (PTR) method for age estimation in Mongolian populations using panoramic radiographs and derive new regression formulae. Moreover, we aimed to assess the accuracy of these formulae in other subjects from the Mongolian population and compare them with the other formulae derived from different Asian populations.The total sample size of the study was 381. The formulae were derived from the examination of panoramic radiographs of 271 individuals aged 15–62 years. Following Cameriere’s method, PTR was calculated for the upper and lower canine teeth. Linear regression analyses were performed between the actual age and that obtained from upper-lower canine PTR and established formulae for age estimation. To verify the formulae, two types of test samples were collected: 73 panoramic radiographs and 37 periapical radiographs. The estimated age was calculated using our new formulae and three other formulae derived from Asian populations.The correlation coefficient between the actual age and that obtained by PTR was significantly negative for both canines. According to our new regression formulae, the differences between the estimated age and actual age showed a bell-shaped curve distribution in both test groups. While using the other formulae derived from the Asian population, the distribution patterns obtained were significantly different in the Mongolian population.This study was the first to examine the relationship between actual age and PTR in Mongolian population, and these results advance the field of forensic science in Mongolia.     

Impact of age on coronary artery plaque progression and clinical outcome: A PARADIGM substudy

BackgroundThe association of age with coronary plaque dynamics is not well characterized by coronary computed tomography angiography (CCTA).MethodsFrom a multinational registry of patients who underwent serial CCTA, 1153 subjects (61 ± 5 years old, 61.1% male) were analyzed. Annualized volume changes of total, fibrous, fibrofatty, necrotic core, and dense calcification plaque components of the whole heart were compared by age quartile groups. Clinical events, a composite of all-cause death, acute coronary syndrome, and any revascularization after 30 days of the initial CCTA, were also analyzed. Random forest analysis was used to define the relative importance of age on plaque progression.ResultsWith a 3.3-years’ median interval between the two CCTA, the median annual volume changes of total plaque in each age quartile group was 7.8, 10.5, 10.8, and 12.1 mm³/year and for dense calcification, 2.5, 4.6, 5.4, and 7.1 mm³/year, both of which demonstrated a tendency to increase by age (p-for-trend = 0.001 and < 0.001, respectively). However, this tendency was not observed in any other plaque components. The annual volume changes of total plaque and dense calcification were also significantly different in the propensity score-matched lowest age quartile group versus the other age groups as was the composite clinical event (log-rank p = 0.003). In random forest analysis, age had comparable importance in the total plaque volume progression as other traditional factors.ConclusionsThe rate of whole-heart plaque progression and dense calcification increases depending on age. Age is a significant factor in plaque growth, the importance of which is comparable to other traditional risk factors.Clinical trial registrationURL: http://www.clinicaltrials.gov. Unique identifiers: NCT02803411.     

Prognostic value of 3′-Deoxy-3′-18F-Fluorothymidine ([18F] FLT PET) in patients with recurrent malignant gliomas

Introduction3′-deoxy-3′-18F-fluorothymidine ([¹⁸F] FLT) PET has been proven to be of value in diagnosis and assessment of glioma grading, in differentiating tumor recurrence from necrosis, in response assessment and in predicting overall survival (OS) in the primary high grade glioma. In this study, we evaluated the value of [¹⁸F] FLT PET-CT in predicting the OS of patients with recurrent malignant glioma.MethodsFifty-six patients with recurrent malignant glioma were enrolled in this prospective study. The PET-CT and contrast-enhanced MRI scans were performed in all patients. Tumor volume was determined from both PET image (proliferative volume, PV) and MRI image (Vol-MRI). Patients were followed up clinically until death. The likelihood of using PET-derived parameters of SUV_max, tumor-to-normal (T/N) ratio, and PV to predict the OS of patients were assessed in comparison with Vol-MRI and other clinical parameters.ResultThe follow up periods for all patients ranged from 1.5 to 35.6 months with median of 9.8 months. Univariate analysis showed that the following parameters were significantly correlated with OS: grade of primary tumor (p = 0.042), Karnofsky performance score (KPS) (p = 0.041), T/N ratio (p < 0.01), Vol-MRI (p = 0.041), and PV (p < 0.001). However, multivariate Cox regression showed that only the PV (p < 0.001) and T/N ratio (p = 0.001) were independent predictors. The thresholds to predict OS were 16.88 cm³ for PV and 10.94 for T/N ratio. Kaplan–Meier analyses using these thresholds showed a significant discrimination between short and long OS groups (p < 0.001).ConclusionThe PV and T/N ratio of tumor on [¹⁸F] FLT PET-CT are independent predictors of survival in patients with recurrent malignant glioma. The PV on [¹⁸F] FLT PET seems to be more predictive than tumor volume on T1-weighted MRI for OS.     

Objective evaluation of chest findings in infants by postmortem computed tomography

PurposeThe purpose of this study was to review the findings of computed tomography (CT) performed early postmortem on infants and to clarify the postmortem CT lung findings that occur in the absence of abnormal histopathological findings.Materials and methodsFrom July 2016 to March 2022, 72 infants were autopsied with postmortem CT (41 boys 31 girls, aged 0–36 (mean 8.2) months). Autopsy and postmortem CT lung findings were compared with the causes of death identified by the autopsies, namely sudden infant death syndrome (n = 37), acute circulatory system disease (18), drowning (7), asphyxia (5), and dehydration/undernutrition (5).ResultsThe %aerated lung volume (−700 HU or less) ranged from 0 % to 33 % (mean 1.5 %, median 0 %), being <1 % in 61 cases (84.7 %) and >3 % in 3/5 (60 %) of the dehydration/undernutrition group. The dehydration/undernutrition group showed significant preservation of lung field air content compared with the other causes of death groups (p < 0.05). Receiver characteristic curve analysis showed a cut off value of 0.8 % and area under the curve of 0.88806. The drowning group had significantly greater pleural cavity fluid retention than the other causes of death groups (p < 0.05). No correlation was found between postmortem interval and pleural cavity fluid retention. However, resuscitation time and pleural cavity fluid retention were correlated.ConclusionEvaluation of CT values on postmortem lung fields of infants usually reveals a marked decrease in air content. When air content exceeds 0.8% on infant postmortem CT, dehydration/undernutrition should be considered in the differential diagnosis.     

Development of age-estimation formula using postmortem oral findings: A pilot study

The goal of this pilot study was to develop an age-estimation formula and assess its effectiveness after evaluating individual intraoral findings. A total of 198 Japanese adults were included, and intraoral findings were collected from the corpses. To analyze the condition of each tooth, 20 items were established for intraoral findings, and seven tooth states were established. Logistic regression analysis was used to estimate the impact of age on each intraoral finding. Sequentially, linear regression was applied to verify the correlation between age and type of tooth, and multiple regression was used to correlate age-dependent factors. The intraoral findings with age dependency were tooth stump, edentulous jaw, attrition, no caries, dental prostheses, partial dentures, and complete dentures. Tooth stump, attrition, and dental prostheses showed positive multicollinearity. Missing tooth, extant tooth, normal teeth, and untreated lost teeth were age-correlated. Multiple regression analysis included age as the response variable and five factors as the explanatory variables in a new age-estimation formula, resulting in ± 10 years for 86.96% of cases (60–69 years old), 76.47% (70–79 years old), and 61.05% of all cases. The multiple correlation was 0.551, and the contribution rate of the multiple regression formula was 0.304. The accuracy of the proposed age-estimation formula was within ± 10 years for 61.05% of all subjects. However, the accuracy of age estimation in subjects aged 60–79 years was excellent (76.47–86.96%), which showed that this age-estimation formula would be effective for estimating the age of middle-aged to older subjects.     

Changes of intrathoracic trachea with respiration in children: A metrical assessment based on 3D CT models

AimTo assess the tracheal volume and the effect of respiration through segmentation on CT-scans in children.Material and methodsChest-CT of 100 patients divided into males and females, aged 3–16 years, were retrospectively assessed. Subjects underwent inspiratory and expiratory CT-scans. Tracheal volume was segmented through ITK-SNAP software. Volume, length, anteroposterior, laterolateral diameters, and T1-T10 distance were measured. The percentage ratio between expiratory and inspiratory phases was calculated: significant differences according to sex for inspiratory and expiratory measurements were assessed through a one-way ANCOVA test using T1-T10 distance as covariate (p < 0.05). Differences in percentage changes according to sex and age were assessed through Mann-Whitney test and calculation of Pearson's correlation coefficient, respectively (p < 0.05).ResultsNo statistically significant difference according to sex was found for any measurement (p > 0.05). For the percentage ratio between inspiratory and expiratory phase, no difference was found according to sex for any measurement (p > 0.05). The percentage ratio of tracheal volume and length between expiratory and inspiratory phases showed a negative correlation with age (p < 0.05).ConclusionsThis study provides a novel contribution to the assessment of tracheal size in healthy children: future studies will verify the same measurements in patients affected by tracheomalacia to improve diagnosis.