Radiomorphometric evaluation of the frontal sinus in relation to age and gender in Saudi population

Ayesha Shireen; Ayesha Shireen; Saurabh Goel; Saurabh Goel; Iffat M Ahmed; Iffat M Ahmed; Abrar M Sabeh; Abrar M Sabeh; Wafaa Mahmoud; Wafaa Mahmoud; Ayesha Shireen; Ayesha Shireen; Saurabh Goel; Saurabh Goel; Iffat M Ahmed; Iffat M Ahmed; Abrar M Sabeh; Abrar M Sabeh; Wafaa Mahmoud; Wafaa Mahmoud

doi:10.4103/jispcd.JISPCD_222_19

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ORIGINAL ARTICLE

Year : 2019 | Volume : 9 | Issue : 6 | Page : 584-596

Radiomorphometric evaluation of the frontal sinus in relation to age and gender in Saudi population

Ayesha Shireen¹, Saurabh Goel², Iffat M Ahmed³, Abrar M Sabeh³, Wafaa Mahmoud⁴
¹ Department of Oral Medicine and Radiology, Pacific Dental College and Hospital, PAHER University, Udaipur, Rajasthan, India; Department of Oral and Maxillofacial Surgery, Alfarabi Private College for Dentistry and Nursing, Jeddah, Kingdom of Saudi Arabia
² Department of Oral Medicine and Radiology, Pacific Dental College and Hospital, PAHER University, Udaipur, Rajasthan, India
³ Department of Oral and Maxillofacial Surgery, Alfarabi Private College for Dentistry and Nursing, Jeddah, Kingdom of Saudi Arabia
⁴ Department of Restorative Dentistry, Alfarabi Private College for Dentistry and Nursing, Jeddah, Kingdom of Saudi Arabia

Date of Submission	16-May-2019
Date of Acceptance	06-Aug-2019
Date of Web Publication	22-Oct-2019

Correspondence Address:
Dr. Iffat M Ahmed
Department of Oral and Maxillofacial Surgery, Alfarabi Private College for Dentistry and Nursing, Jeddah.
Kingdom of Saudi Arabia

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/jispcd.JISPCD_222_19

Abstract

Background: Radiographs have been used for forensic identification purpose. At times when only skull remains are found and other means of identification fail, radiographs of skull may be used for identification purpose. Aim: The objective of this study was morphometric evaluation of the frontal sinus by using digital posteroanterior skull radiograph in relation to age and gender and to establish its forensic importance. Materials and Methods: The study was conducted at Alfarabi Private College for Dentistry and Nursing, Jeddah, Kingdom of Saudi Arabia. It included 400 subjects (200 males and 200 females), aged 14–70 years. Radiographs of the individuals were taken by digital radiography, and morphometric evaluation of frontal sinus was carried out by using Adobe Photoshop CS3 Extended. Results: Unilateral absence of sinus was noted in 2.5% males and 1.5% females. Bilateral absence was noticed in 2% males and 0.5% females. Right and left frontal sinus symmetry was seen in 83.20% of the individuals. The left-dominated asymmetry was observed in 6.98% individuals. The right-dominated asymmetry was observed in 9.82% individuals. Simple logistic regression analysis of gender by different variables showed right width and left width, which are most suited regressors for sex determination. The rate of accuracy in classification of males and females varied from 67.70% to 95.90%. Stepwise multiple regression analysis of estimation of age by different variables showed right sinus height is the best predictor of age. Conclusion: In this study, the radiographic images of the frontal sinus showed significant morphological difference in relation to age and gender in Saudi population. On the basis of this evidence, it is proposed that the morphologic evaluation of frontal sinus can be used for personal identification.

Keywords: Digital posteroanterior skull radiograph (PA skull radiograph), forensics, forensic odontology, frontal sinus, personal identification

How to cite this article:
Shireen A, Goel S, Ahmed IM, Sabeh AM, Mahmoud W. Radiomorphometric evaluation of the frontal sinus in relation to age and gender in Saudi population. J Int Soc Prevent Communit Dent 2019;9:584-96

How to cite this URL:
Shireen A, Goel S, Ahmed IM, Sabeh AM, Mahmoud W. Radiomorphometric evaluation of the frontal sinus in relation to age and gender in Saudi population. J Int Soc Prevent Communit Dent [serial online] 2019 [cited 2019 Dec 11];9:584-96. Available from: http://www.jispcd.org/text.asp?2019/9/6/584/269751

Introduction

Human beings are born with an identity and deserve the right to die with an identity.^[1] The term identity refers to the determination of the individuality of a person.^[2] The identification of a dead body may be required in cases of sudden and unexpected fatalities such as explosions, fires, accidents involving different modes of transportation, mutilated or decomposed mortal remains, or criminal actions, which frequently need great medicolegal expertise.^[2],[3] Various methods are used to establish the identity of unknown remains. The reliability of each method varies and depends on the available bones and their condition.^[4] The only method that can give a totally accurate result is the deoxyribonucleic acid (DNA) identification, but it cannot be used in all situations for several reasons.^[2],[4]

Morphological features depicted on the radiographs must meet the following two requirements in order to be of forensic identification worth: first, the feature must be unique to the individual; second, it must remain unchanged over time despite the continuing life processes. The frontal sinuses fulfill both these criteria. The first study of the anatomy of the frontal sinuses using radiographic methods was conducted by Turner and Porter.^[5]

The aim of this study was morphometric evaluation of the frontal sinus by using digital posteroanterior (PA) skull radiograph in relation to age and gender and to establish its forensic importance.

Materials and Methods

The study subjects were selected from the outpatients visiting the Department of Oral and Maxillofacial Surgery at Alfarabi Private College for Dentistry and Nursing, Jeddah, Kingdom of Saudi Arabia, between the age range of 14 and 60 years. The study approval was obtained by the institutional ethics committee (ethical approval letter number: 1907/01), and informed consent according to the World Medical Association, Declaration of Helsinki, was obtained from the patients who participated in the study. Sample size with a power of 90% was estimated before the start of the study and based on statistical analysis, the number of subjects (n) needed was 384 (so approximately 400 subjects were included in the study).

A total of 400 subjects (200 males and 200 females) were divided among various age groups of ≤20, 21–30, 31–40, 41–50, and 51–60 years, including equal number of both males and females. Subjects were included in the study after recording their demographic data, brief history of present illness, past medical or surgical history. A copy of birth certificate was obtained from the subjects (to compare with the radiographic results later).

Inclusion criteria

Apparently healthy individuals with no visible features of asymmetrical skull.

Age range of the patient 14 years onward.

Exclusion criteria

Hereditary facial asymmetries.

History of orthodontics treatment or orthognathic surgery.

History of maxillofacial trauma.

History or clinical characteristics of any type of systemic disorders such as bone diseases, nutritional and endocrinal diseases.

Methodology

Radiographs of 400 individuals were taken using Kodak 9000 Extraoral Imaging System (Marne la Vallee Cedex 2, France). Digital PA views of the skull were taken by a single operator. The position of patient’s head was standardized according to manufacturer’s instructions. All radiographs were assessed so that only high-quality and correctly positioned radiographs were included. Carestream Dental imaging software 6.13.0 CS 3D (Toulouse Cedex 1, France) Imaging was used and the images were analyzed using Adobe Photoshop CS3 Extended software (San Jose, CA, USA).

Frontal sinus

Following measurements were taken on PA view as suggested by Camargo et al.^[6]:

Right frontal sinus height and width

Left frontal sinus height and width

Left area, right area was obtained only for the portion of frontal sinus projected above the baseline, that is, superior border of the orbit

Linear measurements for each radiograph were obtained using Viewbox 3.0 software and expressed in centimeters. The reliability and reproducibility of frontal sinus measurements were assessed twice by two investigators within one-month interval, where the data of first session were masked at the second session. By this method, a general consensus was reached.

Comparison of the measurements showed no significant statistical difference.

Yoshino’s frontal sinus pattern for each subject was established using following parameters:

Frontal sinus size

Bilateral asymmetry

Superiority of the side

Outline of upper border (left Ou1, right Ou2)

Partial septa (Ps)

Supraorbital cells (Sc)

Each of these parameters was allocated a code number for their characteristics to determine the frontal sinus pattern of the individual.

Following frontal sinus patterns were observed on PA radiograph:

Symmetrical (S)

Left-dominated asymmetry (LDA)

Right-dominated asymmetry (RDA)

Unilateral aplasia (UA)

Bilateral aplasia (BA)

Statistical procedures

Statistical data analysis was carried out using the Statistical Package for the Social Sciences (SPSS), version 20.00 package (SPSS, Chicago, Illinois).

Results

In this study, of 400 subjects, Unilateral absence of sinus was noted in five male subjects (2.5%) and three female subjects (1.5%). Bilateral absence was noticed in four male subjects (2%) and one female subject (0.5%) [Table 1]. UA and BA were excluded from the study so now total sample comprised 191 male and 196 female subjects.

Table 1: Unilateral aplasia and bilateral aplasia of frontal sinus in different studies

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[Table 2] shows distribution of male and female by age groups. Mean age of male subjects was 31.72 years, and that of female subjects was 32.57 years. Therefore, mean age of total subjects altogether was 32.15 years.

Table 2: Distribution of male and females by age groups

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[Figure 1] shows comparison of male and females with frontal sinus pattern. The frontal sinus symmetry was observed in 83.20% of the individuals (154 males and 168 females). The leftdominated asymmetry was observed in 6.98% of the individuals (13 males and 14 females). The right-dominated asymmetry was observed in 9.82% of the individuals (24 males and 14 females).

Figure 1: Comparison of male and females with frontal sinus pattern.

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The descriptive statistic mean values, standard deviation, and P value using Mann–Whitney U test are shown in [Figure 2]. The mean value for all variables is consistently higher in males compared to that in females. Likewise, all response variables are greater in left frontal sinus compared to those in right frontal sinus in both males and females. P < 0.05 is considered to be statistically significant.

Figure 2: Comparison of male and female with different variables

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[Table 3] presents simple logistic regression analysis of gender by different variables, which shows right width and left width are most suited regressors for sex determination. The accuracy rate in classification of males and females varied from 67.70% to 95.90% and we also developed individual equation for Saudi population. The inclusion of all variables was measured using the formula:

Table 3: Simple logistic regression analysis of gender by different variables

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where, x1 is right height, x2 is left height, x3 is right width, x4 is left width, x5 is right area, and x6 is left area. The probability is calculated from the logit value (P) from the preceding expression by the following equation: P = e^logit/(1 + e^logit).

The measurements of association between estimated probability and observed responses [Table 3] are important to determine the prediction capacity of the proposed model. A concordance index of 95.90% was found, which indicated a model that shows good association between predicted response and observed sex. The results show that there is 4.10% wrong classifications. There are strong indications for the importance of the right width of the frontal sinus in the determination of sex (95.90%).

Stepwise logistic regression analysis of gender by different variables shows that right height, right width, left height, left width, left area, and right area are the best predictors of differentiation between males and females [Table 4].

Table 4: Stepwise logistic regression analysis of gender by different variables

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Simple linear regression analysis of estimation of age by different variables shows P <0.05, which is statistically significant [Table 5].

Table 5: Simple linear regression analysis of estimation of age by different variables

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Stepwise multiple regression analysis of estimation of age by different variables shows right height is the only one best predictor of estimation of age [Table 6].

Table 6: Stepwise multiple regression analysis of estimation of age by different variables

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Discussion

Identification of human remains is required for personal, social, and legal reasons.^[7] Schuller was the first to report the use of radiographs for the purpose of identification in 1921.^[3]

In forensic identification, among the paranasal sinuses, the frontal sinus is the one that is of most interest and significance due to its irregular shape and because of its individual characteristics, which make the frontal bone unique for every individual, just as with fingerprints.^[8],[9],[10]

Dental identification by radiographs forms the main crux of forensic odontology.^[3]

Dental identification by radiographs is broadly of two types: comparative and reconstructive. Reports state that 72% of positive identification in modern forensics have been obtained by comparison of antemortem and postmortem radiographs.^[11] In forensic identification, comparative radiography is most commonly used. To study the sinuses, Waters (sinus) projection of the skull is one of the most commonly used radiographs but it has been noted that PA radiograph of skull by Caldwell technique helps in better view of frontal sinus than Waters projection, where slight foreshortening of the image is seen.^[11],[12] Lateral cephalograms, conventional computed tomography (CT), and cone-beam computed tomography (CBCT) have also been used to study the frontal sinus.^[12],[14]

The disadvantages of conventional CT and CBCT include higher doses than two-dimensional imaging and expensiveness when compared to radiographs.^[15] Therefore, in this study, the methodology using digital PA radiography is simple and cost-effective, providing high accuracy in human identification using frontal sinus.^[16]

In this study, all the response variables studied showed mean value to be consistently larger in males compared to that in females [Table 4], which can be attributed to the fact that the morphological differences in the cranium between the two sexes are determined mainly by genetic factors more so by nutritional, hormonal, or muscular factors.^[17],[18] These aspects explain why frontal sinus is on an average larger in males compared to that in females.^[16],[19]

Left frontal sinus was greater than the right side in both males and females, which is similar to the study conducted by Camargo et al.^[6] and Pondé et al.^[20] but is in contrast with the study conducted by Kotrashetti et al.^[16] The existence of one side larger than the other is due to their independent development.^[16],[21] It is common to find one sinus larger than the other, and the larger sinuses may cross the midline and even overlap the other.^[22] We also found the morphology of each frontal sinus of both males and females was different and also asymmetrical, consequently confirming the findings of various studies performed in the past [Figure 3].^{[8],[22],[23],[24],[25],[26]} Asymmetry for the frontal sinus of both sides is a rule because of the unequal resorption of the dipole during sinus development.^[21]

Figure 3: Observed groups and predicted probabilities

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The variable difference by each research can be attributed to the influence of environmental and genetic factors on the frontal sinus. The systemic factors, which influence the frontal sinus morphology within each population, are craniofacial configuration, frontal bone thickness, and growth hormone levels [Table 7].^[22]

Table 7: Comparison of some previous similar studies

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Comparison of frontal sinus pattern in males and females showed frontal sinus symmetry in 83.20% of the individuals (154 males and 168 females). LDA was observed in 6.98% of the individuals (13 males and 14 females). RDA was observed in 9.82% of the individuals (24 males and 14 females).

Stepwise multiple regression analysis of estimation of age by different variables shows right height is the best predictor of age. There are, however, limitations in the use of the frontal sinus in establishing individual identity, moreover its size varies with the role of genetic, environmental, and systemic factors.^[26]

However, there is no doubt that interpopulation variation seriously affects the frontal sinus morphological features. The results reported in this study indicate that it is possible to achieve accuracy and precision using a discrete number of morphological features of the frontal sinus to determine the sex and for the personal identification of unknown skeletal remains. It has been suggested that the frontal sinus has the potential to be used for personal identification, age estimation, and sexual dimorphism.

Conclusion

The morphologic evaluation of frontal sinus is a useful technique to determine gender and age of an individual in Saudi population. Logistic regression analysis of frontal sinus is a simple, reliable, and low-cost method to determine gender in an adult individual. Simple linear regression analysis of frontal sinus can be used in the estimation of age. Further studies on frontal sinus morphology are required with larger sample size to ascertain the accuracy level in determining sex and age of an individual.

Acknowledgement

This study was done as part of a thesis submitted to Pacific Dental College and Hospital, PAHER University, Udaipur, Rajasthan, India, for the award of PhD degree in Oral Medicine and Radiology, Dental Sciences.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

[38]

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