Dental Imaging

In dentistry optical coherence tomography (OCT) technology has shown some promise as a method to distinguish between enamel, dentin, and restorative materials of tooth specimens. Ultrasound (US) technology has been reported with applications in dentistry to image deep tissues which offers a means to further characterize various soft tissue anomalies. While it is believed that both US and OCT technologies have real-time imaging potential for dentistry, their ability to visualize multiple types of simulated defects within root canal systems has yet to be tested. This study was setup to help determine the efficacy of two catheter-based imaging probes in prepared root canals containing areas of interest. Areas of interest herein are cited as vertical fracture lines, simulated perforations, resorptive-like defects, sites of intact dentin, and void space variance of the lumen. 33 human teeth were selected and underwent root canal analysis using 2 commercially available intravascular cathet...

In 1895 W.C Roentgen invented roentgenograms, which today are simply referred to as x-rays or radiographs. Although x-rays have evolved over the years, the principle remains the same except that today's techniques utilize only a fraction of the x-ray doses used in the early days of radiology. The x-ray technology is the 'workhorse' of fundamental diagnostic imaging. Testing is fast, easy, and painless. When the x-rays pass through the body they are weakened by the many types and layers of tissues. Bone being denser, absorbs a greater amount of radiation and they appear more prominently (e.g. whiter) than soft tissue. The energy is directed into a film cassette placed behind the targeted body part, held behind an intensifying phosphor screen. The screen absorbs x-rays, gives out light and exposes the film, which is subsequently processed to form a final image in much the same manner as a photographic film.

We report the existence of polarization memory effect (PME) in optical coherence tomography and investigate its potential applications in dental imaging. We performed the study in three steps. First, microsphere scattering phantoms of different sizes were imaged in order to validate experimental results with PME theory. Both linearly and circularly polarized light were used to probe the samples. Second, healthy tooth samples were scanned and polarization memory effect was identified in dentin. In this step, specific verification and signal processing were performed to rule out possible image interpretation by birefringence effect. Third, we evaluated dentin demineralization with PME. Results show polarization memory can be useful to characterize this dynamic mineralization process for early caries detection and rehabilitation.

Efforts are made in radiographic examinations to obtain the best image quality with the lowest possible absorbed dose to the patient. In dental radiography, the absorbed dose to patients is very low, but exposures are relatively frequent. It has been suggested that frequent low-dose exposures can pose a risk for development of future cancer. It has previously been reported that there was no significant difference in the diagnostic accuracy of approximal carious lesions in radiographs obtained using tube voltages of 60 and 70 kV. The aim of this study was, therefore, to evaluate the patient dose resulting from exposures at these tube voltages to obtain intraoral bitewing radiographs. The absorbed dose distributions resulting from two bitewing exposures were measured at tube voltages of 60 and 70 kV using Gafchromic(®) film and an anatomical head phantom. The dose was measured in the occlusal plane, and ± 50 mm cranially and caudally to evaluate the amount of scattered radiation. The ...

If I had to describe Tanimoto Sensei using a single word I would say kindness. When I was attending the PhD course in Hiroshima University, I frequently looked at him and thought: "If I have the chance to be an educator, I would like to be like that man." The generosity, respect and friendship he employed to treat the students is fascinating. By that time, Professor Tanimoto had just come back from his post-doc in the USA full of ideas and dreams. Since that, many of the ideas had become projects and many of the projects had become a real benefit for the patients. Tanimoto Sensei has an extensive and relevant scientific production and some of them are described in the next pages. I believe this interview is especially interesting because it is enriching to know how professors from the other side of the globe conduct orthodontic education and science. Finally, I would like to express my sincere gratitude to the other professors that assisted in this article and to Dental Press Journal of Orthodontics for the opportunity to conduct the present interview with Professor Tanimoto, a great friend of mine. Emanuel Braga -interview coordinator

C-arm computed tomography is a new and innovative imaging technique. In combination with 2D fluoroscopic or radiographic imaging, information provided by 3D C-arm real time imaging can be valuable for therapy planning, guidance and outcome assessment in the field of modern endodontics. This paper reports a case of complete endodontic treatment using Artis zee C-arm CT system first time in endodontic practice. Introduction The quest for new technologies to incorporate for mutual benefits to the operator and the patient is never ending. Encouraging results have been reported using the latest imaging modalities like Dental Cone Beam CT and Optical Coherence Tomography in endodontics. But none of these systems can provide a three-dimensional real time imaging.

Background: Major challenges encountered to decrease the milliamperes (mA) level in x-ray imaging systems are the quantum statistics, electronic and quantization noise. Back
illuminated (BI) complementary metal oxide semiconductor (CMOS) sensors can acquire low noise and high quantum efficiency images from photon-starved sources. Adaptive filtration (AF) has been used for noise reduction in medical imaging.
Objective: This investigation evaluated mA and median filtration (MF) and AF noise reduction of a low dose x-ray imaging (LDXI) prototype comprising two low mA x-ray sources (miniature and standard), an 11um pixel size BI CMOS sensor coated with a high contrast scintillator-HCS (group 1) and CsI(TI) scintillator/fiber optic plate (group 2).
Materials & Methods: Groups 1 and 2, resolution test pattern (RTP) and dental phantom (DP) were exposed to the miniature and standard low mA x-ray sources in static and dynamic modes. Both groups were then subjected to MF and wiener2 AF. Image resolution was measured in lines per millimeter (lp/mm) and noise reduction was calculated through histograms mean and standard deviation.
Preliminary Results: Groups 1 and 2 were capable to acquire DP x-ray images at 0.1 mA, 70 kVp, 8’ collimation and 0.04 seconds static and dynamic modes at 1.84 R/min. Images at 0.4 seconds were obtained in both DP groups at 70 kVp and 0.01 mA (0.19 R/min). Miniature x-ray source prototype produced a higher dose exposure as compared to standard due to lack of HVL
filtration. The RTP showed Group 2 > Group 1. Noise reduction showed AF>MF>raw image.
Future Directions: As compared to previous research,2 BI CMOS with both coatings and MF and AF permitted halving mA settings while allowing image noise reduction for digital
radiography and dynamic imaging. The LDXI miniature x-ray source feasibility was confirmed in this study upon HVL filtration integration. These LDXI principles could be applied to all dental imaging modalities in the near future.

periapical pathoses. The sensitivity for the MPS was 63% (95% CI 59.2-68.0) for tooth-specific disease and the specificity was 92% (95% CI 92.2-94.5). The likelihood ratios (LR) were LRϩ 9 and LRϪ Ϫ.39. The P value (McNemars P Յ .0001) was significant for MPS compared with FMS.