Reasons for requesting cone-beam computed tomography in children and adolescents: a 10-year study

Abstract Analysis of the reasons for requesting dental cone-beam computed tomography (CBCT) in children and adolescents can provide new evidence to guidelines developed specifically to protect patients from potential harmful effects of ionizing radiation. This retrospective study aimed to determine the reasons for requesting dental CBCT in paediatric patients. We included all patients aged <18 years who underwent CBCT between 2011 and 2021 at the Dentomaxillofacial Radiology Department of Dicle University Dental Faculty. Out of 8214 archived records in total, 1619 CBCT request forms of paediatric patients were examined. These forms provided the data on each participant’s age, gender, requesting department, the reason for the request, and year of the request. We evaluated 762 males and 857 females; 0.68% were aged 4–5 years, 27.55% were 6–11 years, and 71.77% were 12–17 years. The requests for CBCT were made by the Orthodontics Department in 61.4% of cases and by the Surgical Department in 25.82% of cases. The most common indication for CBCT (33.42% of cases) was to determine the presence of embedded teeth. We found a significant correlation between the age group and indications (p < 0.05). The age group of children and adolescents for whom CBCT was requested most often was the 12–17 years age group. In conclusion, the most common indication for CBCT was to determine the presence of embedded teeth in orthodontics. The rate of use of CBCT in the diagnosis and treatment of paediatric patients in dentistry has increased in the last decade.


Introduction
Cone-beam computed tomography (CBCT) in dentistry provides multiplanar (axial, sagittal, and coronal) three-dimensional images that enable the examination of the real sizes of maxillofacial structures with minimal artefacts [1]. CBCT imaging in paediatric patients (<18 years) is used in cases of dentoalveolar trauma to determine the presence of embedded or supplementary teeth, to determine skeletal and dental disorders in patients requiring orthodontic treatment and those having breathing problems, dental anomalies such as root number anomalies, dens in dente or dilaceration, in preoperative orthognathic surgery evaluation, implant treatment, and for the diagnosis of the periapical region and bone pathologies, temporomandibular joint (TMJ) pathologies, cleft-lip palate, root resorption and root fracture, and in patients with autotransplantation and periodontal treatment [2][3][4][5].
Each exposure to ionizing radiation has the risk of permanently changing human DNA and causing oncogenic mutations [6]. Children are 2-10 times more sensitive to radiation than adults as their cells divide more rapidly during growth [6]. The increase in the rate of CBCT use for dentomaxillofacial diagnoses has raised concerns about the radiation risks, particularly for children. While there is limited research evidence to support CBCT indications in children, there is no approach that has used the combined and integrated information about dose levels relevant to the patient and image quality necessary for the indications [7]. Generally, when taking radiographs in dentistry, image examination is performed following the ALARA radiation dose principle. The ALARA principle advocates using the lowest amount of radiation possible to provide diagnostic information in children [8]. The dose received by the patient is determined by the beam parameters, detector type, projection number, protective devices, voxel size, and, most importantly, the imaging area of the field of view (FOV) size according to the area to be examined [9]. Therefore, strategies must be applied to reduce the dose of CBCT applications in children. There should be dose-lowering strategies to determine the indications, limit the area to be examined, avoid control tests, use organ protectors, and determine appropriate acquisition parameters [10].
There is growing understanding that guidelines on when and why CBCT scanning is necessary should be developed to minimize the radiation dose in young patients. As pointed out by hajem et al. [6] to be able to do this, it is important to determine how CBCT is currently being used. Their survey of the requests and indications for CBCT in Swedish children and adolescents prompted us to investigate the indications for CBCT examination in children and adolescents in Turkey over a 10-year period.

Ethics statement
Ethical approval for this study was granted by the Local Ethics Committee of the Dicle University Dental Faculty (Decision No: 2021-22), and this study was conducted in accordance with the principles of the helsinki Declaration.

Medical records
The archived records of all the patients aged <18 years who presented for CBCT examination in the department of Dentomaxillofacial Radiology at Dicle University Dental Faculty between January 2011 and 2021 were consulted. CBCT requests were signed by the dentist in the department by filling out the CBCT forms for all health information and the reasons for the request, and signed by the patient or their parents. All CBCT forms for 2011-2021 requested were examined. CBCT image data of patients under 18 years of age, gender and age distribution, requesting department, reasons for request and distribution by years were tabulated. Each patient's age (in years) at the time of CBCT examination was rounded down to the next whole number and recorded; as such, a patient aged 11 years 10 months was recorded as being 11 years old. Data were analysed by the descriptive statistics method.

CBCT imaging
CBCT images were obtained with an i-Cat (Imaging Sciences International, Inc., hatfield, PA). Most of the CBCT images used in this study were taken with the standard protocol applied in the hospital, with a diameter of 16 cm, a height of 13 cm, 0.4 voxels and 8.9 s. Generally, 0.25, 0.2, 0.125 mm voxel size results in a longer scan time (26.9 s) and produces better resolution but larger radiation dose for patients. The smaller diameter and 0.3, 0.4 voxel size, mean a shorter scan time (8.9 s) for patients, resulting in a lower radiation dose.

Statistical analysis
Data were analysed using IBM SPSS version 21 (IBM SPSS Statistics, Armonk, Ny). Relationships between nominal variables were examined using the chi-square test. In R × C tables, Pearson's chi-square test was used with the Monte Carlo simulation if 20% of the value expected in the cell was <5. Differences are considered statistically significant at the p< 0.05 level in all analyses.

Results
The descriptive statistics are presented in Table 1. Out of 8214 archived CBCT images between 2011 and 2021, 1619 were identified as belonging to patients aged <18 years. The CBCT request forms for children and adolescents constituted 19.71% of all request forms in the last 10 years. The study participants comprised 762 (47.07%) males and 857 (52.93%) females.
There were 11 (0.68%) patients aged 4-5 years, 446 (27.55%) aged 6-11 years, and 1162 (71.77%) aged 12-17 years. The mean age of the patients was 13.7 years. The requests for CBCT were made by the Orthodontics Department in 61.4% of cases and by the Oral, Dental, and Maxillofacial Surgery Department in 25.82% of cases. Concerning the major indications for CBCT, 33.42% were to determine the presence of embedded teeth, 12.42% for jaw and dental lesions, and 11.86% for orthodontic anomalies.
The statistical analysis found significant relationships between age groups, the requesting department and the indication (p < 0.05). In the 4-5 years age group, the highest rates of CBCT request were from the Paedodontics and Surgical Departments, both at the rate of 36.36%, for jaw or dental fracture at the rate of 45.45%. In the 6-11 years age group, the highest rate of CBCT requests was from the Orthodontics Department at 56.05% for embedded teeth at a rate of 26.68%. In the 12-17 years age group, the highest rate of CBCT requests was again from the Orthodontics Department (63.77%) for embedded teeth at a rate of 36.23% (Figure 1).
In paediatric patients, there was a moderate positive correlation between the number of CBCT films requested in dentistry and the period over the last 10 years (p< 0.05) (r= 0.608).

Discussion
The literature on the potential use of CBCT in children and adolescents has reported scarce evidence of the frequency of use for different clinical applications in daily practice. Beyond the more comprehensive use in children and adolescents, there is generally more information in the literature on requests from the orthodontics clinic [11][12][13]. This is because there are more indications for CBCT use in several areas of orthodontics (Table 1). Therefore, this study investigated how dental CBCT is used in children and adolescent patients in all branches of hospital practice, considering that the evaluation of these data would be helpful in developing hospital services related to CBCT for children and adolescents.
Interestingly, in this study, we observed that the rate of use of CBCT in children and adolescents has increased in the last 10 years. Despite the limited use of CBCT in paediatric patients because of the high radiation doses and the longer scanning period  required, an increase has been seen in the rate of use of CBCT as a diagnostic and therapeutic tool for children and adolescents as a result of developments in technology.
Reportedly, the most common indication for CBCT in all patients are implants [14,15]. however, in this study, the rate of requests for CBCT for implant planning was low (1.36%) and the highest number of requests for CBCT for implants was in the 12-17 years age group. This can be explained by the limited use of implants in patients aged <18 years, who are still in the growth and development phases.
hidalgo-Rivas et al. [16] reported 13.7% (out of 2141 patients) and Isman et al. [4] reported 38.72% (out of 850 patients) as paediatric patient CBCT request rates. In our study, the CBCT request rate was 19.71% in the paediatric population of 8214 patients. Gümrü et al. [17] reported that 449 patients among 8.880 CBCT scans were recruited from paediatric patients who are under 14 years of age, representing approximately 5% of all scans. The reason for this difference was thought to be the 12-17 age group of children and adolescents for whom CBCT was requested most frequently [17].
The mean age of the patients was reported to be 13.1 years by hidalgo-Rivas et al. [16], 13.42 years by Isman et al. [4], and 12.35 years by Van Acker et al. [18]. There was no significant difference in the gender distribution between these three studies. In this study, the mean age (13.7) of the patients in the 4-17 years age range and the lack of significant association between participants' sex and indications were consistent with those of similar studies.
In the study conducted by hidalgo-Rivas et al. [16] in the UK, the youngest patients with CBCT requests were 5 years old in Sheffield, 7 years old in Manchester and 6 years old in Leeds. Van Acker et al. [18] reported that the youngest patient was aged 7 years. In paediatric samples, the youngest patient for whom CBCT was requested because of trauma was 2 years old [4]. In this study, the youngest patient was 4 years old, and this was also because of trauma. We believe that the indications against radiation exposure and motion artefacts in very young patients in CBCT for dentistry purposes should be defined.
hidalgo-Rivas et al. [16] reported that CBCT was used most in paediatric patients to determine the presence of embedded teeth and associated root resorption in the teeth. Van Acker et al. [18] reported that CBCT requests were mostly for the follow-up of tooth development, Isman et al. [4] identified the most common indications for CBCT in paediatric patients as malocclusion, dentomaxillofacial anomalies, and the localization of embedded teeth. Dobbyn et al. [13] also reported that the two most common indications were to accurately determine the localization of embedded teeth and to determine the presence of root resorption. Gumru et al. [17] reported that the most common CBCT indication was as embedded teeth followed by bone pathology and dental anomalies.
In this study, the most common indication for CBCT was to determine the presence of embedded teeth (33.42%), followed by jaw and dental lesions (12.42%), which was consistent with the findings of some previous studies. The differences in the most common indication between this study and some other studies were probably due to the evaluation of orthodontic indications under different sub-headings. The proportion of requests made from orthodontics was 61.40%. The findings that requests were made for orthodontic treatment purposes and within TMJ pathologies and that the fewest requests were for periodontitis (0.31%) were consistent with the recommendations of the DIMITRA. European DIMITRA (Dentomaxillofacial paediatric imaging: an investigation toward low-dose radiation-induced risks) multicentre and multidisciplinary project recommends two-dimensional imaging in periodontal assessment [7].
Isman et al. [4] evaluated patients in three groups of 2-6, 7-12, and 13-18 years, and reported CBCT requests for embedded tooth localization at a significantly higher rate in the two older groups than in the youngest group, and requests because of trauma at a significantly higher rate in the youngest age group. In this study, considering that the differences in patient characteristics during the dentition development period could affect CBCT indications, the patients were evaluated in three different age groups (4-5, 6-11, and 11-17 years), and the conclusion was that there was a significant correlation between the age groups and indications. The indication for trauma was more frequent in the youngest age group, and the most frequent indication for CBCT in the other two groups was to determine the presence of embedded teeth. CBCT was requested most in the 12-17 years age group, which is consistent with the age at which orthodontic treatments can be started.
Akleyin and yavuz [19], Doğan et al. [20], and Bernardes et al. [21] concluded that CBCT was superior in identifying vertical root fractures in the adult population. When the CBCT indications of children were evaluated, requests were found to be mostly for the identification of jaw and root fractures in trauma patients followed by root resorption. There are reports that the resorption of dental roots can be visualized better on CBCT [22].
The first study on this subject in the literature, which reported that the most common reasons for CBCT requests among children and adolescents in Japan were supernumerary teeth (51%), tooth eruption disorders (28%), and investigations of the TMJ (9.2%), was conducted by Suzuki et al. [23]. In this study, developmental anomalies of the teeth were seen at a rate of 4.14%. This can be explained by the understanding that two-dimensional panoramic films are considered sufficient for the diagnosis of developmental anomalies in paedodontics. CBCT can be requested if further treatments are necessary.
Deveci and Gümrü reported that CBCT scanning was requested in 1686 children and adolescent patients for orofacial clefts and syndromes (9.5%) [24]. The rate of CBCT requests for cleft-lip palates (11.43%) and dental syndromes (0.8%) was notable in this study, as the University is in the southeast of Turkey where there is a much higher rate of consanguineous marriages than in the rest of the country. It has been stated in the literature that CBCT is preferred as a good option for the evaluation of bone and root development as it provides better image quality [25]. There is not much information about the superiority of CBCT in the case reports published on congenital deformities. Ectodermal dysplasia was the syndrome for which this study observed most CBCT requests.
Radiation doses obtained from large FOV dental CBCT scans are 4-42 times higher than the dose obtained from a panoramic radiograph [26]. The use of dental CBCT in children and adolescents is a controversial subject because of the radiation dose effects and especially the increasing "routine" use of large FOV scans. If a special CBCT service for children and adolescents is planned, a limited FOV machine would be an appropriate choice. Such data could be of use for hospitals when planning the development of services, including the purchase of CBCT equipment [27].
In an examination of the FOVs of all patients for whom CBCT was requested from the orthodontics department between 2006 and 2011, Dobbyn et al. [13] reported that the maxilla only (62%), both jaws (32%) and the mandible only (6%) were examined. Isman et al. [4] reported the face to be the most imaged area (74.2%), as well as the maxilla (7.6%), the mandible (85.2%), both jaws (12%; maxilla and mandible), and teeth (0.9%) when the FOV was examined.
In this study, in the acquisition of the whole face in the same FOV range at 0.4 voxels 8.9 s on the I-CAT device with the routine application of CBCT imaging suggested that clinicians do not have sufficient information about this imaging technique. Despite there being several FOV options on the CBCT machine used, it seems that the use of the highest FOV was preferred to obtain a clearer image. The unnecessary use of a high FOV ignores the ALARA principle. Therefore, especially in paediatric patients, dentists should carefully evaluate the FOV used.
The SEDENTEXCT (Safety and Efficacy of a New and Emerging Dental X-Ray Modality) project is a European intervention developed by six universities and an industrial partner with the aim of developing comprehensive, evidence-based guidelines on the use of CBCT in dentistry. The SEDENTEXCT report published in 2012 recommended that CBCT examinations should be used in cases where the rationale for its request in each patient is to add new information to patient management and the benefits outweigh the risks, and when lower-dose conventional radiography is considered insufficiently adequate. It was also stated that if the CBCT equipment offers volume size options that provide a lower radiation dose to the patient, and if the CBCT equipment supports several resolution options, the resolution compatible with the smallest dose for a sufficient diagnosis should be used [28,29].
The results of this study demonstrated an increasing rate of use of CBCT in children and adolescents over the last 10 years. Although there are reports on CBCT use in the paediatric population, no guidelines have been developed on CBCT use in paediatric dentistry in Turkey. Therefore, as there is no evidence-based consensus on what constitutes an appropriate level of use in children, further research would be useful to investigate the results of the increasing use of CBCT by clinicians. Van Acker et al. [17] also stated that when evaluating the conducted studies, it is important to take into consideration the different regions of the world, variations in availability, access to CBCT and cultural and ethnic characteristics.
This study had some limitations, the main one being that migrants to our region have low accessibility to oral and dental healthcare services due to the cultural structure and low economic conditions, and as CBCT imaging is an expensive method, its availability may be low.

Conclusions
Along with the increasing frequency of requests for CBCT among children and adolescents over the years, there has also been an increase in the CBCT experience of clinicians and its use in legal problems. Children and adolescents constituted 19.71% of all the patients who underwent CBCT throughout the 10-year study period. The most common indication for CBCT in this paediatric population was to determine the localization of embedded teeth as requested by the orthodontics department. During radiological examinations in dentistry, there can be a need for the development of CBCT exposure protocols for paediatric patients according to clinical indications.

Disclosure statement
No potential conflict of interest was reported by the authors.

Funding
The author(s) reported there is no funding associated with the work featured in this article.