Dental X-ray Devices Research Articles

Review: Dosimetry in Dental Radiology

The aim of this study was to determine, by a systematic review, the radiation doses of different dental x-ray devices, their particular effects, and the cumulative results of various studies done with various dosimeters. Google scholar was searched from 2014 to 2021 using the following keywords: radiation dose, dosimeters in dentistry, types of dosimeters, Cone beam computed tomography (CBCT) radiation. The references of selected papers were also analyzed. Articles were chosen that fit the criterion for utilizing dosimeters in dentistry applications. This review was separated into four sections: (1) biological impacts of radiation, (2) dosimeter characteristics, (3) dosimeter kinds, and (4) the findings of numerous investigations employing various dosimeters. According to a recent assessment of dosimetry based on different investigations conducted with dosimeters, the effective dosage supplied has decreased since the introduction of radiography techniques. As a result, radiological method selection is critical in dental dosage administration.

Accuracy in positioning of dental X-ray images – A comparative study of a portable X-ray device and a wall-mounted device

IntroductionThe benefits of portable dental X-ray devices remain controversially debated. This study aimed to compare the accuracy in positioning dental X-ray images using handheld (Nomad Pro 2) and wall-mounted (Heliodent Plus) X-ray devices. Materials and methodsRadiographical imaging was exercised on a maxillofacial phantom using the handheld dental X-ray device Nomad Pro 2 (Kavo Kerr, Biberach, Germany) and the wall-mounted dental X-ray device Heliodent Plus (Sirona Dental Systems, Bensheim, Germany). Accuracy of device positioning (i.e., centeredness and perpendicularity) was measured as horizontal and vertical deviation (pixels and millimeters) from a centrally positioned crosshair. The reproducibility of the results was tested for 80 images per device and operator. IBM SPSS (SPSS Inc., Chicago, IL) was used for statistical analyses. ResultsCenteredness of produced dental X-rays was significantly better for the wall-mounted device than for the handheld device in both deviation from the x-axis (p = 0.042) and y-axis (p = 0.020). The perpendicularity of the produced dental X-rays was significantly better for the handheld device than for the wall-mounted device for both horizontal (p < 0.001) and vertical (p < 0.001) plains. ConclusionsHandheld dental X-ray devices appear to provide a high degree of accuracy in image positioning, especially in regard to proper perpendicular image angulation.

ESTIMATING RADIATION DOSE TO MAJOR ORGANS IN DENTAL X-RAY EXAMINATIONS: A PHANTOM STUDY.

The radiation doses absorbed by major organs of males and females were studied from three types of dental X-ray devices. The absorbed doses from cone-beam computed tomography (CBCT), panoramic and intraoral X-ray machines were in the range of 0.23-1314.85 μGy, and were observed to be high in organs and tissues located in or adjacent to the irradiated area, there were discrepancies in organ doses between male and female. Thyroid, salivary gland, eye lens and brain were the organs that received higher absorbed doses. The organ absorbed doses were considerably lower than the diagnostic reference level for dental radiography in China. The calculated effective radiation doses for males and females were 56.63, 8.15, 2.56μSv and 55.18, 8.99, 2.39μSv, respectively, when using CBCT, the panoramic X-ray machine and intraoral X-ray machine. The effective radiation dose caused by CBCT was much higher than those of panoramic and intraoral X-ray machines.

Image quality of a portable X-ray device (Nomad Pro 2) compared to a wall-mounted device in intraoral radiography

ObjectivesThe aim of this study was to determine whether a handheld (HH) X-ray device (Nomad Pro 2) is capable of producing equivalent or even superior X-ray image quality in comparison to a wall-mounted (WM) dental X-ray unit (Heliodent Plus) on the basis of objectifiable image quality parameters.MethodsAnatomical, radiological and biological dental X-ray image quality parameters of a handheld dental X-ray device (Nomad Pro 2, Kavo Kerr, Biberach, Germany) were compared to a standard wall-mounted dental X-ray unit (Heliodent Plus, Sirona Dental Systems, Bensheim, Germany) using a maxillofacial phantom. In addition, the effect of different operators (dentists, dental students, dental assistants) on the dental X-ray image quality was measured.ResultsHH and WM devices showed comparable image quality for anterior teeth, premolars, molars and bitewing images. During the two-month investigational period, the radiation exposure level for the operator of the Nomad Pro 2 was 0.1 mSv for 203 images. Dentists as the highest trained personnel enrolled in the study achieved better image quality with the Nomad Pro 2 as compared to dental students and dental assistants, especially in the molar region.ConclusionsA HH device delivers a comparable image quality to a WM device. In addition, there seem to be short learning curves with regard to image acquisition when using a handheld device, which is further minimised by the previous training of the operating personnel. HH dental X-ray devices, such as the Nomad Pro 2 are a promising adjunct for dental radiology in cases where WM units are of limited practicability.

Evaluation of stray radiation to the operator for five hand-held dental X-ray devices.

Objectives:Evaluate stray radiation to the operator, as represented by a plane within the significant zone of occupancy (SZO), produced by five models of hand-held intraoral dental X-ray devices (HIDXDs).Methods:The stray radiation for five models of HIDXDs was measured, using an anthropomorphic tissue-equivalent head phantom as a scattering object. An ionization chamber was used to measure the air kerma (μGy) at 63 positions in a 160 cm high by 60 cm wide plane that was 10 cm behind the X-ray device, identified as being within the SZO.Results:Based on the measured air kerma from stray radiation of five different HIDXDs, the estimated annual air kerma at all measured spatial positions was calculated. When calculated using a median air kerma of 0.8 mGy at the distal end of the cone, as typically required for digital image receptors,1 the ranges for estimated annual air kerma in the SZO across the devices were 0.14–0.77 mGy for the median, 0.41–1.01 mGy for the mean, and 1.32–2.55 mGy for the maximum. Similarly, when calculated using a median air kerma of 1.6 mGy as typically required for D-speed film,2 the ranges for estimated annual air kerma across the devices were 0.28–1.54 mGy for the median, 0.83–2.03 mGy for the mean, and 2.64–5.10 mGy for the maximum.Conclusions:From measured air kerma values of stray radiation in the SZO, estimated annual exposures to the operator for HIDXDs are expected to be greater than from conventional wall-mounted or portable devices activated from a protected area (at a distance or behind shielding). HIDXDs should therefore only be used when patient accessibility makes their use necessary and the use of a portable device on a stand or a wall-mounted device is not reasonably feasible. This approach would keep occupational radiation exposures of dental workers as low as reasonably achievable.

ESTIMATION OF EFFECTIVE DOSE OF DENTAL X-RAY DEVICES

This study aims to estimate the effective doses of dental X-ray devices under common scanning protocols. After putting TLDs in the Alderson Radiation Therapy Phantom, we exposed the phantom under common scanning protocols of three dental X-ray devices, namely CBCT, dental panoramic machine and intraoral round cone device. Then effective doses were calculated using the measured absorbed doses of organs and tissues. Tissue weighting factors recommended by the ICRP were adopted in the calculation. Effective doses under common scanning protocols of three Dental X-ray devices were obtained. The effective dose of dental CT was 0.20 mSv, and that of dental panoramic machine and intraoral radiography were 0.013 and 0.0050 mSv, respectively. The tissue absorbed doses of dental CT scan were 0.63 mGy of brain, 7.7 mGy of salivary glands, 8.7 mGy of thyroid and 4.0 mGy of the lens of the eye. The tissue absorbed doses from dental panoramic machine are 0.62 mGy of salivary glands and 0.25 mGy of thyroid. And finally the tissue absorbed dose of intraoral radiography was 0.80 mGy of salivary gland. Among the three dental X-ray devices studied, dental CBCT scan can cause much higher effective dose than the other two. Brain, salivary glands, thyroid and the lens of the eye are tissues receiving relatively higher absorbed doses.

RADIATION DOSE FROM DENTAL RADIOGRAPHY IN INDONESIA: A FIVE-YEAR SURVEY.

Dose metrics on intraoral and panoramic dental radiography were analyzed to preliminarily indicate dose trend of dental radiology equipment in Indonesia. Measurements were performed in 71 healthcare institutions involving a total of 92 dental X-ray devices. Imaging modes are categorized into 'low dose' and 'high dose' based on the task. The 75th percentile for intraoral IAK was 2.8 and 4.3 mGy for 'low' and 'high' dose modes, respectively while for panoramic devices the 75th percentile of the KAP for 'low' and 'high' dose modes were 85.2 and 192.4 mGy cm2, respectively. Results compared with local regulatory recommendation for intraoral units indicated that 38.8 and 6.3% of measured dose modes on analogue and digital devices, respectively, were above the recommended range. The dose trend can be used as reference for local regulations concerning patient dose in dental radiography and preliminary value prior to the establishment of national diagnostic reference level.

Using hand-held dental x-ray devices: Using hand-held dental x-ray devices

Since the introduction of hand-held x-ray units in dentistry, a few inexpensive devices have emerged that lack the necessary safety measures and failed to meet U.S. Food and Drug Administration (FDA) standards. They are advertised actively and sold online in the United States.The authors present several safety issues associated with an imported hand-held x-ray device that has not been cleared by the FDA and compare the device with an FDA-cleared unit.The authors found that the non-FDA-cleared device posed major safety hazards, including high radiation doses to patients and operators, lack of operator shielding, lower-than-acceptable kilovolt (peak) value, inadequate collimation, lack of an audible signal of x-ray generation and absence of a so-called dead-man switch.Dental professionals must be aware of unsafe x-ray equipment and use only those devices that have been cleared by the FDA to protect themselves and their patients.

Assessment of microbiological contamination of radiographic devices in School of Dentistry

Although dental radiology is not directly involved in either invasive procedures or in the use of piercing-cutting material, the high-touch areas of dental x-ray device, including radiographic films, are a potential source of infection. The purpose of this study was to assess the amount of cross infection present in the dental x-ray devices of the School of Dentistry of the Federal University of Maranhão by investigating the presence of pathogenic microorganisms in high-touch areas of dental x-ray devices (tube head, timer button, portable processing box and lead apron). Twenty surfaces of 4 dental radiology clinics were cultured in different media. The results showed that 70 percent of the surfaces had contamination. All the dental x-ray devices assessed were contaminated (tube head, timers or both) as well as all the lead aprons. The portable processing boxes showed 75 percent of contamination. The groups found no statistical significance between the different surfaces assessed and the microorganisms. The highest frequent microorganisms found were from Staphylococcus genus. The authors concluded that because of the high incidence of contamination found, the x-ray devices used in the dental clinics could be at potential risk of cross infection, demonstrating the necessity for applying biosecurity practices when taking radiographic and during radiographic processing.

Image quality assessment and medical physics evaluation of different portable dental X-ray units

Introduction Recently developed portable dental X-ray units increase the mobility of the forensic odontologists and allow more efficient X-ray work in a disaster field, especially when used in combination with digital sensors. This type of machines might also have potential for application in remote areas, military and humanitarian missions, dental care of patients with mobility limitation, as well as imaging in operating rooms. Objective To evaluate radiographic image quality acquired by three portable X-ray devices in combination with four image receptors and to evaluate their medical physics parameters. Materials and methods Images of five samples consisting of four teeth and one formalin-fixed mandible were acquired by one conventional wall-mounted X-ray unit, MinRay ® 60/70 kVp, used as a clinical standard, and three portable dental X-ray devices: AnyRay ® 60 kVp, Nomad ® 60 kVp and Rextar ® 70 kVp, in combination with a phosphor image plate (PSP), a CCD, or a CMOS sensor. Three observers evaluated images for standard image quality besides forensic diagnostic quality on a 4-point rating scale. Furthermore, all machines underwent tests for occupational as well as patient dosimetry. Results Statistical analysis showed good quality imaging for all system, with the combination of Nomad ® and PSP yielding the best score. A significant difference in image quality between the combination of the four X-ray devices and four sensors was established ( p < 0.05). For patient safety, the exposure rate was determined and exit dose rates for MinRay ® at 60 kVp, MinRay ® at 70 kVp, AnyRay ®, Nomad ® and Rextar ® were 3.4 mGy/s, 4.5 mGy/s, 13.5 mGy/s, 3.8 mGy/s and 2.6 mGy/s respectively. The kVp of the AnyRay ® system was the most stable, with a ripple of 3.7%. Short-term variations in the tube output of all the devices were less than 10%. AnyRay ® presented higher estimated effective dose than other machines. Occupational dosimetry showed doses at the operator's hand being lowest with protective shielding (Nomad ®: 0.1 μGy). It was also low while using remote control (distance > 1 m: Rextar ® <0.2 μGy, MinRay ® <0.1 μGy). Conclusions The present study demonstrated the feasibility of three portable X-ray systems to be used for specific indications, based on acceptable image quality and sufficient accuracy of the machines and following the standard guidelines for radiation hygiene.

Forensic oral imaging quality of hand-held dental X-ray devices: Comparison of two image receptors and two devices

Recently, different portable hand-held and battery-powered dental X-ray units have become available. Especially for forensic odontological purposes, they offer diverse advantages such as for use in disaster areas and crime-scene locations as also in autopsy rooms and mortuaries. For any application, the most important feature of these hand-held devices is the delivered image quality. The aim of this study is to evaluate the radiographic image quality acquired by two portable X-ray devices in combination with two types of image receptors and to compare the findings with the image quality of a standard intra-oral X-ray device. Eleven samples consisting of eight teeth, two dry skeletal specimens and one formalin-fixed mandible part were mounted on blocks for standardised (re)positioning. Radiological images were acquired with two hand-held (AnyRay ® 60 kVp, 0.02–4.00 mAs and NOMAD ® 60 kVp, 0.023–2.277 mAs) and one wall-mounted (MinRay ® 60/70 kVp 0.14–22.4 mAs) X-ray device combined with two image receptor systems (VistaScan ® phosphor storage plate (PSP) and SIGMA ® M CMOS Active Pixel technology sensor). The effect of X-ray source-to-object distance (SOD) was checked at 20 cm in conjunction with object to image receptor distances (OIDs) of 0.8 and 2.5 cm. For each parameter setup, the exposure times were run from low till high. An expert consent statement was achieved by agreement of four expert observers selecting the optimal images based on a developed four point quality rating system. Next, a selection of the images was assembled in a set of 198 observation screens and scored by seven observers. The observation screens were designed to compare observer scores, relations between devices, receptors and OIDs and images obtained from the different devices at equal exposure levels (mAs). All results were statistically analysed. Radiological image quality was significantly higher for phosphor plate compared with the CMOS digital receptor system ( p < 0.0001). Furthermore, a significantly superior image quality was obtained for OID = 0.8 than for OID = 2.5 ( p = 0.039). A significant difference in image quality between the three devices was also established ( p = 0.02). The present study demonstrated the feasibility of portable X-ray systems for forensic odontological applications based on rendering optimal image quality, provided an in vitro guideline of optimal parameter settings and offered a radiological image database usable in further research.

Study of the aluminum-zinc alloy as an alternative method of filtration in dental X-ray devices

The aim of this study was to evaluate the effects of alternative filtration with the aluminum-zinc alloy in dental X-ray devices, regarding the energy spectrum, dose, contrast and image quality. This study was carried out comparing the conventional aluminum filter with aluminum-zinc alloy filters of various thicknesses and with different percentages of zinc in the alloy (2, 3, 4 and 5%). A conventional X-ray device operating with 60 and 70 kVp as well as D- and E-speed films were utilized in order to obtain images of a phantom and an aluminum step wedge. The utilization of Al-Zn filters resulted in a spectrum without hardening of beams. The rate of kerma in the air decreased 18.53%, without any alteration in contrast and image quality. The results revealed that the 2% Al-Zn alloy filter with 1.99 mm of thickness, utilized with the tension of 60 kVp and D-speed film, had the best performance. It reduced the rate of kerma without varying the indices of contrast and maintained image quality at acceptable levels, without increasing the time of exposure.