Dental Imaging System Research Articles

Lightweight deep learning methods for panoramic dental X-ray image segmentation

Dental X-ray image segmentation is helpful for assisting clinicians to examine tooth conditions and identify dental diseases. Fast and lightweight segmentation algorithms without using cloud computing may be required to be implemented in X-ray imaging systems. This paper aims to investigate lightweight deep learning methods for dental X-ray image segmentation for the purpose of deployment on edge devices, such as dental X-ray imaging systems. A novel lightweight neural network scheme using knowledge distillation is proposed in this paper. The proposed lightweight method and a number of existing lightweight deep learning methods were trained on a panoramic dental X-ray image data set. These lightweight methods were evaluated and compared by using several accuracy metrics. The proposed lightweight method only requires 0.33 million parameters (sim 7.5 megabytes) for the trained model, while it achieved the best performance in terms of IoU (0.804) and Dice (0.89) comparing to other lightweight methods. This work shows that the proposed method for dental X-ray image segmentation requires small memory storage, while it achieved comparative performance. The method could be deployed on edge devices and could potentially assist clinicians to alleviate their daily workflow and improve the quality of their analysis.

REVOLUTIONIZING DENTAL DIAGNOSTICS: ADVANCEMENTS AND CHALLENGES IN AI-POWERED IMAGING SYSTEMS

This study explores AI-powered dental imaging systems in detail, emphasizing how they are revolutionizing diagnoses. These systems analyze radiographs, cone-beam computed tomography (CBCT) scans, and magnetic resonance imaging (MRI) scans with efficiency thanks to machine learning algorithms. We give a summary of their potential for automated interpretation, treatment suggestions, and dental disease prognosis. Reviews from academic institutions highlight how much better they are at identifying dental decay and creating individualized treatment plans than older techniques. Furthermore, the effectiveness of computer vision methods—in particular, convolutional neural networks (CNNs)—in identifying dental caries is emphasized. Issues with interpretability, ethical issues, and workflow integration still exist despite their promise. In order to overcome these obstacles and optimize the advantages of AI in dentistry, we stress the significance of interdisciplinary cooperation, which will eventually improve patient care and results.

Penetration Estimation in SEM, EDAX Dental Imaging Systems for Desensitization Application

Background: In the dental field, many people undergo an extreme fear of injections, which is referred to as trypanophobia. The medical procedures that involve injections in the dental field to create numbness raises a certain level of discomfort to all of the patients to an extent that the patients avoid treating their teeth or show an anxious or avoidance behavior. Hence, needle phobia is one of the more common phobias amongst people but was not officially recognized as a phobia in dentistry for a long time. In rural areas, some patients, mainly elderly people, might go away without treating their damaged tooth due to fear of injections. Aim: Thus, setting this as the major point of consideration, the researchers have put forth a new concept of dental treatment of creating desensitization without injections rather by adopting a new concept as “iontophoresis”, which causes the ions of specific charges to penetrate the semipermeable membrane, which helps in performing surgeries in the dental field. In the present manuscript, the ‘iontophoresis’ method, along with the imaging systems, was adopted and 45 tooth samples were taken and tested with four different ionic gels that are used in the dental field, and the results were analyzed using the imaging systems of SEM and EDAX for clear analysis. Results: The results through these imaging systems show that the ions have penetrated the tooth, which causes a desensitizing effect in the tooth and makes it numb, so that dental operations can be performed easier and with more perfection. The process of performing dental surgery with a needless process is that the patient to be treated by the dentist is exposed to a gel with electrodes wherein the ions penetrate the tooth, which causes numbness. Conclusion: The incorporation of needle-free injection through the concept of iontophoresis and imaging systems in the dental field introduces a new era in the field of dentistry, making the process simple.

Stress distribution in restorations with glass fiber and polyetheretherketone intraradicular posts: An in silico analysis.

This study evaluated stresses generated at maxillary central incisor (21) root restored with lithium disilicate crown (LDC), and glass fiber (GFP) or polyetheretherketone (PEEK) post. 3D models created by computed tomographic image (i-CAT Cone Beam 3D Dental Imaging System) reproduced maxillary central incisor. Each model had prosthetic LDCs (2.0 mm thick) cemented to GFP or PEEK posts with dual resin cement. Different loads were applied to each model (cervical, incisal, axial, middle). At maximum principal stress, PEEK showed higher stress than GFP in all loads, but with qualitative similarity. At minimum principal stress, PEEK and GFP showed qualitative and quantitative similarities, except axial load. Maxillary central incisor restored with GFP or PEEK and LDC presented, in general, similar stress intensity and distribution for main occlusal loads. Only two of sixteen occlusal loads tested (cervical for maximum principal; axial for minimum principal) showed significant quantitative difference.

Infrared Clinical Enamel Crack Detector Based on Silicon CCD and Its Application: A High-Quality and Low-Cost Option.

Enamel cracks generated in the anterior teeth not only affect the function but also the aesthetics of the teeth. Chair-side tooth enamel crack detection is essential for clinicians to formulate treatment plans and prevent related dental disease. This study aimed to develop a dental imaging system using a near-IR light source to detect enamel cracks and to investigate the relationship between anterior enamel cracks and age in vivo. A total of 68 subjects were divided into three groups according to their age: young, middle, and elderly. Near-infrared radiation of 850 nm was used to identify enamel cracks in anterior teeth. The results of the quantitative examination showed that the number of enamel cracks on the teeth increased considerably with age. For the qualitative examination, the results indicated that there was no significant relationship between the severity of the enamel cracks and age. So, it can be concluded that the prevalence of anterior cracked tooth increased significantly with age in the young and middle age. The length of the anterior enamel cracks tended to increase with age too; however, this result was not significant. The silicon charge-coupled device (CCD) with a wavelength of 850 nm has a good performance in the detection of enamel cracks and has very good clinical practicability.

SADA communique to members - Licence and quality control tests for dental diagnostic X-ray imaging systems

Members have been receiving notification from Inspection Bodies about their X-ray equipment being due for inspection.
 On enquiry, it has been discovered that, in some instances, this notice was based on erroneous data that Inspection bodies may have received from the Radiation Control, who had not correctly updated their records, due to "a lack of manpower".
 SADA strongly advises members who receive this notification to check their documentation before booking said inspections and, if the notification is incorrect, to request their usual inspection body to correct their records.
 SADA has serious concerns about the current legal framework and enforcement of the Act governing X-ray equipment. It questions the Code of Practice and more particularly, the legal standing of inspection bodies, licensing delays and the entire legislative framework. To this end, SADA has made an extensive written submission to the Minister of Health raising our concerns. In the meantime, as the legislative framework applies to practitioner, in its flawed framework, we provide members useful information for the benefit of members around the whole issue of licensing and testing of X-ray equipment so that members are properly informed when receiving notices of inspections or having to licence their new or used X-ray equipment.

Morphological and dimensional assessment of the maxillary sinus for human identification and sexual dimorphism: A study using CBCT

Abstract The use of tomographic images for ante and post-mortem comparisons is a safe and useful method for human identification. Thus, the present study aimed to evaluate the reproducibility of the morphometric assessment of the maxillary sinus for human identification and investigate whether sexual dimorphism is present in a Brazilian population, using Cone Bean Computed Tomographic (CBCT) images. One hundred tomographic images were selected as sample. The exams were acquired using the iCAT Next Generation® CBCT machine. Two previously trained and calibrated examiners evaluated morphological and dimensional parameters of the maxillary sinus region in two different moments with a 15 days minimum interval between the evaluations. The evaluation was carried out on a 19-inch monitor and with iCAT Workstation Dental Imaging System software in a light-dimmed and quiet environment. Cohen's Kappa test analyzed categorical and discrete variables. Mann-Whitney-U-test and Student's t-test were used to analyze the differences between the mean values of dimensional parameters for males and females with a significance level of 5% (p

Mouthwash to Deliver Indocyanine Green for Near Infrared Dental Fluorescence Imaging

Dental diseases significantly impact the quality of life and human populations; the current X-ray diagnostic dental imaging method may also bring the potential health risks to humans. This study used human extracted teeth and rats as animal model to test a new near-infrared (NIR) dental fluorescence imaging system with a painless mouthwash for administering indocyanine green (ICG). Our results show that the mouthwash delivery of ICG enables better image contrast than subcutaneous injection at short imaging time (1-10 minutes after ICG administration): for the erupted rat model, in vivo mouthwash (live rat) showed better imaging quality than injection method or ex vivo mouthwash (dead rat); for the unerupted molar, both mouthwash and injection showed the clear dental structures of the unerupted molars through endoscopic imaging; the dosage of mouthwash was at least 10 times lower than injection method. For human teeth, efficient image contrast was obtained in as short as 1 minute of ICG immersion; caries lesions were represented as a bright dot in the NIR windows. Overall, mouthwash serves as a painless and convenient method for administration of ICG; ICG-assisted NIR mouthwash dental imaging provides a low-cost and safe dental imaging tool for the diagnosis of dental diseases.

Automated classification of dual channel dental imaging of auto-fluorescence and white lightby convolutional neural networks

Prevention is the most effective way to reduce dental caries. In order to provide a simple way to achieve oral healthcare direction in daily life, dual Channel, portable dental Imaging system that combine white light with autofluorescence techniques was established, and then, a group of volunteers were recruited, 7200 tooth pictures of different dental caries stage and dental plaque were taken and collected. In this work, a customized Convolutional Neural Networks (CNNs) have been designed to classify dental image with early stage caries and dental plaque. Eighty percentage ([Formula: see text]) of the pictures taken were used to supervised training of the CNNs based on the experienced dentists’ advice and the rest 20% ([Formula: see text]) were used to a test dataset to test the trained CNNs. The accuracy, sensitivity and specificity were calculated to evaluate performance of the CNNs. The accuracy for the early stage caries and dental plaque were 95.3% and 95.9%, respectively. These results shown that the designed image system combined the customized CNNs that could automatically and efficiently find early caries and dental plaque on occlusal, lingual and buccal surfaces. Therefore, this will provide a novel approach to dental caries prevention for everyone in daily life.

Evaluation of two dental digital imaging systems based on quality scorings, burn-out effects and cervical width determination

Background/Aim: The aim of the present study is to evaluate diagnostic accuracy of two generic image receptors with CMOS and PSP sensors for image quality scoring (IQS), burnout incidences (BI) and cervical widths (CW) with regard to four different exposure times. Material and Methods: 43 incisor teeth within 15 paraffin block models were exposed at 4 different exposure times both for the CMOS and PSP groups, and a total number of 120 images were obtained. All images were evaluated by 3 dentomaxillofacial radiologists via 3 different criteria; IQS, BI, CW. Results: Diagnostic quality scorings between groups displayed statistically significant difference for 0,1; 0,125 and 0,16 SEC exposure times. PSP group revealed higher IQS. For 0,125 and 0,16 seconds exposure times, PSP group showed higher percentages of BI. Average CW were lower in PSP group. Although no statistically significant difference was found between average CW vs. exposure times in the CMOS group; PSP group revealed significant differences among exposure times. We can state that, the PSP system displayed higher image quality so exposure times can be reduced, alas, the same conclusion is not possible with CMOS system used. Conclusions: Image quality perception is higher in PSP system we used, compared with CMOS system. PSP system display more burnout effects with increasing exposure times, while CMOS system is constant.

Pulsed 70 kV X-ray sensing behavior of Cu2HgI4 thick films

X-ray photoconductors are widely used in flat panel X-ray detectors in medical and dental imaging systems. In the present work, X-ray photoconductivity measurement of Cu2HgI4 thick film was performed using a real-time intraoral X-ray machine. To perform the sensing measurement, wet chemical derived Cu2HgI4 sample was coated as a thick film by slurry deposition route on top of the tin coated copper patterned electrode. Prior to the sensing measurement, Cu2HgI4 powder sample was characterized using powder X-ray diffraction, scanning electron microscope, energy dispersive x-ray analysis, Fourier transformed infrared spectroscopy and diffused reflectance spectroscopy. These analysis confirms the sample is in single phase with crystallites are in sub-spherical morphologies. The resistance of Cu2HgI4 thick film was measured under the presence and absence of pulsed 70 kV X-ray for various exposure durations from 0.06 to 3.2 s using a Keithley 2450 source meter. Appreciable sensitivity against intraoral pulsed 70 kV X-ray sensing behavior of Cu2HgI4 thick films explore the possibility of utilizing it as a photoconductor for flat panel X-ray imaging detectors.

Examination of foramen tympanicum: an anatomical study using cone-beam computed tomography.

The foramen tympanicum (FT) is an osseous dehiscence of the temporal bone and usually closes by the age of 5 years. The foramen is located posteromedial to the temporomandibular joint and anteroinferior of the external auditory canal. The aim of this study is to define the prevalence, location and size of the foramen. We retrospectively examined 200 cone-beam computed tomography (CBCT) images (400 ears). We used a CBCT dental imaging system (GALILEOS, Sirona Dental Systems, Bensheim, Germany) working at 15-30 mA and 98 kV. We noted size and location (unilateral and bilateral) of the present FT. Foramen tympanicum was determined in 11.5% of 200 patients (they had FT at least on one side of the head). This was bilateral in 5 (2.5%) patients. Prevalence of the FT was significintly higher in females (8%) than in males (3.5%). FT was found more frequently on the left side (7.5%) than on the right side (4%). Mean axial diameter was 1.13 mm (range 0.23-4.43 mm), and mean sagittal diameter was 1.44 mm (range 0.22-3.99 mm). Considering that FT was present in 11.75% of patients, radiologists and clinicians should be aware of the possible presence of this defect. It is known that this developmental dehiscence may cause herniation of temporomandibular joint, formation of salivary otorrhea, and spread of tumour or infection to the infratemporal fossa from external auditory canal. This study showed that CBCT may be preferred for imaging these conditions. (Folia Morphol 2018; 77, 2: 335-339).

Endoscopic near-infrared dental imaging with indocyanine green: a pilot study.

Current dental diagnosis, especially tooth abnormalities, relies largely on X-ray-based imaging, a technique that requires specialized skills and suffers from ionizing radiation. Here, we present a pilot study in rats of an efficient, ionizing-radiation-free and easy-to-use alternative for dental imaging. Postnatal rats at different ages were injected with indocyanine green and molars were imaged by a laboratory-designed endoscopic near-infrared (NIR) dental imaging system. The results indicate that the endoscopic NIR dental imaging can be used to observe the morphology of postnatal rat molars, especially at early postnatal stages when morphology of the molar is indistinguishable under visible conditions. A small abnormal cusp was observed and distinguished from the normal cusps by the NIR dental imaging system. Dental structures, such as unerupted molars, can be imaged as soon as 10 min after the injection of indocyanine green; imaging after 24 h shows improved imaging contrast. Overall, the endoscopic NIR fluorescence dental imaging system described here may be useful in dental research; this technique may serve as a safe, real-time imaging tool for dental diagnosis and treatment beyond experimental systems in the future.

The in vitro and in vivo reproducibility of a video-based digital imaging system for tooth colour measurement

ObjectivesTo assess the robustness of a new custom built video-based digital imaging system (VDIS) for measuring tooth colour and whiteness under in vitro and in vivo conditions. MethodsThe VDIS imaging system was developed for tooth colour measurement and evaluated in vitro and in vivo. The in vitro validation used extracted human teeth (HT, n=14) stored in water and VITA Classical shade guide tabs (SG, n=16). These were measured by the VDIS at baseline, 5min, 2h, 1 week and 2 weeks to evaluate the system repeatability. For in vivo validation, adult volunteers (male/female, n=34) with two natural, unrestored central incisors had their teeth imaged using the VDIS at baseline, 5min and 2h (3 images each) by two different operators to evaluate time and operator effects. Between taking individual images, subjects moved from the imaging-frame to assess the effect of re-positioning on reproducibility. From the in vitro and in vivo images, the average tooth RGB values were obtained, and the CIELAB values and a tooth whiteness index WIO value were calculated. Repeatability and reproducibility of VDIS imaging system was assessed using appropriate repeated measurement analysis techniques and ANOVA. ResultsThe measurement variations in vitro were between 1 and 2 units of ΔWIO and the average colour differences were less than 1 ΔE*ab unit. For the in vivo study, analysis of the CIELAB parameters and WIO showed that subject variability accounted for between 82 and 99% of the observed variability in the measurement process. The operator variability was less than 0.5% and the overall measurement error was found to be only 0.3% for WIO. Across assessment times the variability was less than 0.5%. ConclusionsThe dental imaging system V-DIS was shown to be a highly reproducible means for tooth colour and whiteness measurement. Clinical significanceDigital imaging based techniques gives a highly reproducible approach to measuring tooth colour.

RadioVisioGraphy: A Simplified Nasal Bone Radiographic Imaging Tool.

Nasal fractures account for approximately 50% of all facial fractures. Although nasal fractures are the most common facial fracture, they often go unnoticed by physicians and patients. A simple radiographic imaging of the isolated nasal bone can be done by RadioVisioGraphy dental imaging system with high resolution and less radiation.

A Tileable CMOS X-Ray Line Detector Using Time-Delay-Integration With Pseudomultisampling for Large-Sized Dental X-Ray Imaging Systems

This paper presents a low-power and low-noise tileable CMOS X-ray line detector with time-delay-integration (TDI) for large-sized dental X-ray imaging systems. The proposed X-ray line detector with TDI adopts pseudomultisampling (PMS) using shifted clocks for the single-slope analog-to-digital converter (ADC) to reduce the required clock cycles for the ADC. The reduced clock cycle decreases the dynamic power and power fluctuation to ensure power stability for large-sized X-ray detectors. The TDI X-ray line detector with PMS was fabricated using 0.18- $\mu \text{m}$ CMOS image sensor process technology with a stitching process, which has an image format of 1010 $\times $ 86 and a pixel size of $75\,\,\mu \text{m}\,\,\times 75\,\,\mu \text{m}$ . The X-ray line detectors are tiled with $1 \times 2$ and $1\,\,\times3$ arrays to enlarge the active areas for dental panoramic and cephalometric X-ray imaging systems, respectively. The measurement results show the random noise of 0.43 LSB and a dynamic range of 78.5 dB, when the number of TDI stages is 86 and the number of PMS steps is 4. The dynamic current and power consumption per ADC are reduced from 157.4 $\mu \text{A}$ and $283.32~\mu \text{W}$ to $41.2~\mu \text{A}$ and 74.16 $\mu \text{W}$ , respectively, when PMS is adopted for TDI.

Diagnostic methods for dental caries used by private dental practitioners in Ankara.

This study aimed to investigate the preference profiles of various types of diagnostic tools and methods used by private dental practitioners in Ankara for detecting dental caries. Private dental practitioners, in five districts of Ankara, were provided with questionnaires comprising demographic characteristics, possession of dental imaging systems, and methods used for caries diagnosis. The questionnaires were retrieved after 1-3 visits. Of 722 questionnaires, 371 were returned. Data were analyzed using frequency analysis and Chi-square tests. The completed questionnaires were obtained from 160 women and 168 men, the response rate was 51.4% aged 25-69 years; 28.4% of them were specialists. Most participants possessed a dental radiography (RG) device. Air drying and sharp explorers were the most commonly preferred methods used for caries diagnosis. There was no significant association between using a sharp explorer and sex or being a specialist (P = 0.110, 0.226, respectively). Almost one-third of the dentists with an experience of <11 years, never used an RG device to detect occlusal caries (P = 0.003). Only three participants reported the use of DIAGNOdent, while two participants used fiber-optic transillumination (FOTI). It was observed that visual-tactile examination using sharp explorer accompanied with radiographs were among the main instruments used for detecting carious lesions. Usage of magnification tools, FOTI, and DIAGNOdent were low.

Effect of palatal form on movement of teeth during processing of complete denture prosthesis: An in-vitro study.

Aim:The aim of this in-vitro study was to assess the influence of shallow and deep palatal forms on the movement of teeth during the processing of complete denture prosthesis.Materials and Methods:Maxillary casts with shallow and deep palatal forms were selected and duplicated to make 10 casts of each palatal form. Base plates were constructed and teeth were arranged in their anatomic positions. Metal pins with true apex were placed on the central groove of the right and left first molars and one on the incisive papilla area as a reference point. Casts were scanned using i-CAT Vision Q 1.9 (i-CAT cone beam 3D dental imaging system by Imaging Sciences International, PA, USA), which has 360° rotational tomography. The distances between the apices of metallic pin inserts on the teeth and fitted point of reference were recorded in buccopalatal axes at waxed up stage, after deflasking, and after finishing and polishing.Results:Results showed a statistically significant movement of teeth in shallow and deep palatal forms during all stages of complete denture processing. In shallow palatal form dentures, there was a significant tooth movement in palatal direction between Stages 1 and 2 (P ≤ 0.05) and buccal movement between Stages 2 and 3. In deep palatal form dentures, teeth showed a statistically significant (P ≤ 0.05) movement in buccal direction during all stages of denture processing.Conclusion:Teeth showed significant movement during processing of acrylic resin dentures. Overall, the movement of teeth in shallow palatal form dentures was in palatal direction, whereas in deep palatal form dentures, the movement of teeth was in buccal direction.

3D reconstruction based on compressed-sensing (CS)-based framework by using a dental panoramic detector

In this work, we propose a practical method that can combine the two functionalities of dental panoramic and cone-beam CT (CBCT) features in one by using a single panoramic detector. We implemented a CS-based reconstruction algorithm for the proposed method and performed a systematic simulation to demonstrate its viability for 3D dental X-ray imaging. We successfully reconstructed volumetric images of considerably high accuracy by using a panoramic detector having an active area of 198.4 mm × 6.4 mm and evaluated the reconstruction quality as a function of the pitch (p) and the angle step (Δθ). Our simulation results indicate that the CS-based reconstruction almost completely recovered the phantom structures, as in CBCT, for p≤2.0 and θ≤6°, indicating that it seems very promising for accurate image reconstruction even for large-pitch and few-view data. We expect the proposed method to be applicable to developing a cost-effective, volumetric dental X-ray imaging system.

Digital tomosynthesis (DTS) with a Circular X-ray tube: Its image reconstruction based on total-variation minimization and the image characteristics

In this paper, we introduce an effective imaging system for digital tomosynthesis (DTS) with a circular X-ray tube, the so-called circular-DTS (CDTS) system, and its image reconstruction algorithm based on the total-variation (TV) minimization method for low-dose, high-accuracy X-ray imaging. Here, the X-ray tube is equipped with a series of cathodes distributed around a rotating anode, and the detector remains stationary throughout the image acquisition. We considered a TV-based reconstruction algorithm that exploited the sparsity of the image with substantially high image accuracy. We implemented the algorithm for the CDTS geometry and successfully reconstructed images of high accuracy. The image characteristics were investigated quantitatively by using some figures of merit, including the universal-quality index (UQI) and the depth resolution. For selected tomographic angles of 20, 40, and 60°, the corresponding UQI values in the tomographic view were estimated to be about 0.94, 0.97, and 0.98, and the depth resolutions were about 4.6, 3.1, and 1.2 voxels in full width at half maximum (FWHM), respectively. We expect the proposed method to be applicable to developing a next-generation dental or breast X-ray imaging system.