Optimizing radiation safety in dentistry: Clinical recommendations and regulatory considerations.

BACKGROUND: The value of dental radiographs to oral health care decision making must be balanced with radiation safety to minimize patient exposure and occupational risk of oral health care providers. This review summarizes recommendations and regulatory guidance regarding dental radiography and cone-beam computed tomography. An expert panel presents recommendations on radiation safety, appropriate imaging practices, and reducing radiation exposure. TYPES OF STUDIES REVIEWED: A systematic search run in Ovid MEDLINE, Embase, and Cochrane Database of Systematic Reviews identified relevant topical systematic reviews, organizational guidelines, and regulatory reviews published in the peer-reviewed literature since 2010. A supplemental search of the gray literature (eg, technical reports, standards, and regulations) identified topical nonindexed publications. Inclusion criteria required relevance to primary oral health care (ie, general or pediatric dentistry). RESULTS: A total of 95 articles, guidance documents, and regulations met the inclusion criteria. Resources were characterized as applicable to all modalities, operator and occupational protection, dose reduction and optimization, and quality assurance and control. PRACTICAL IMPLICATIONS: Understanding factors affecting imaging safety and applying fundamental principles of radiation protection consistent with federal, state, and local requirements are essential for limiting patient ionizing radiation exposure, in conjunction with implementing optimal imaging procedures to support prudent use of dental radiographs and cone-beam computed tomographic imaging. The regulatory guidance and best practice recommendations summarized in this article should be followed by dentists and other oral health care providers.

Effect of 3 different disinfection methods on the image quality of photostimulable phosphor plates.

OBJECTIVE: The aim of this study was to assess the effects of 3 disinfection protocols on the quality of images acquired with a photostimulable phosphor (PSP) plate system. STUDY DESIGN: Thirty DIGORA Optime PSP plates were divided into 3 groups of 10. Group 1 was disinfected with 95% ethanol. Group 2 was disinfected using germicidal disposable wipes. Group 3 was disinfected with 95% ethanol, followed by hydrogen peroxide gas sterilization. Images of a quality assurance phantom were acquired on each plate before disinfection (baseline images). Disinfection and imaging cycles were repeated 45 times for each plate. Changes in image quality were assessed between baseline and final images. Image quality was evaluated for dynamic range, spatial resolution, and contrast perceptibility. The Fisher exact test was used to detect statistically significant differences among the 3 disinfection methods relative to decreases in image quality parameters between the baseline and final radiographs. Additionally, for each group, the Z-test was used to detect statistically significant decreases in image quality parameters between baseline and final images. The significance level was established at P < .05. RESULTS: No statistically significant differences were detected among the disinfection groups or relative to baseline values for any group at a 5% significance level. CONCLUSIONS: Hydrogen peroxide gas may be considered to prevent cross-contamination while preserving image quality. Regular quality assurance testing is recommended to maintain image quality over time.

Cone beam computed tomography: What's left to know?

The use of cone beam computed tomography (CBCT) in dentistry has grown exponentially since its inception and that trend continues. Though CBCT has become routine to some, its popularity in dentistry only demonstrates that education in CBCT is needed now more than ever. This presentation covers key components to consider when purchasing a CBCT unit and describes concepts in interpretation and radiation safety.

The importance of the ANSI ADA Standard for digital intraoral radiographic systems-a pragmatic approach to quality assurance.

The need for quality assurance (QA) for digital dental radiography has existed since the introduction of digital imaging; however, the methods and phantoms required to achieve it were not available. This resulted in a chaotic approach to address QA based largely upon subjective analysis of image quality. The American National Standards Institute (ANSI)/American Dental Association (ADA) Quality Assurance Standard 1094 for Digital Intraoral Radiographic Systems (DIRS) presents a paradigm shift to a scientific and objective method of QA rather than one based on subjective assessments. This standard takes into account the contributions of all components of the digital imaging chain that affect final image quality rather than assessing the various components in isolation. The optimal image is determined for each DIRS through objective analysis of the image quality properties of dynamic range, spatial resolution, and contrast perceptibility. Image optimization, a critical component of a quality assurance program, is the proper balance between diagnostic image quality and radiation dose to the patient. This publication counters disseminated myths and misconceptions with scientific evidence and will help dental practitioners appreciate and understand the benefits of the new ANSI/ADA Standard on QA for DIRS.

Osteosarcoma of the jaws: Report of 3 cases with emphasis on the early clinical and radiographic signs.

Osteosarcoma is the most common primary malignancy of the jaws and is treated by radical surgical resection. Early detection is crucial because removing the lesion with clean margins contributes most to the outcome. We present 3 cases of osteosarcoma occurring in the interradicular region of the mandible, 2 of which were thought to represent nonmalignant processes upon initial presentation. All 3 demonstrated early but significant clinical and radiographic features indicative of the malignant disease process. Radiographically, these cases had in common unilateral periodontal ligament (PDL) space widening, displacement of teeth, and growth of the crestal bone. Clinically, all 3 cases presented with a painless intraoral swelling. Case 1: a 20-year-old African American man presented with swelling and loose teeth with a duration of 1.5 months. Histopathologic diagnosis of osteoblastic osteosarcoma, high grade, was made. Case 2: a 75-year-old White man presented with a 2 × 2 cm expansile lesion with a duration of 2 months. Histopathologic diagnosis of chondroblastic osteosarcoma was made. Case 3: a 63-year-old White woman presented with a 5- to 6-mm lesion with a duration of at least 1 month. Histopathologic diagnosis of chondroblastic osteosarcoma was made. All 3 cases were treated with wide surgical resection.

Cryoanalgesia is Associated With Decreased Postoperative Opioid Use in Minimally Invasive Repair of Pectus Excavatum.

BACKGROUND: Postoperative pain control is challenging after pectus excavatum repair. We aimed to understand the impact that cryoanalgesia had on opioid utilization and outcomes of pediatric patients undergoing minimally invasive repair of pectus excavatum (MIRPE). METHODS: A single-center retrospective cohort study was conducted of all patients (< 18 y) who underwent MIRPE (2011-2019). Patients receiving cryoanalgesia were compared to those who did not. The primary outcome was total postoperative, inpatient, opioid use, measured as milligrams of oral morphine equivalents per kilogram (OME/kg). Univariate and multivariable analyses were performed. RESULTS: Of 35 patients, 20 received cryoanalgesia (57%). Baseline characteristics were similar. Patients who received cryoanalgesia had a lower opioid requirement: median 2.3 mg OME/kg (IQR 1.2-3.1), versus 4.9 mg OME/kg (IQR 2.9-5.8), P < 0.001. Accounting for receipt of cryoanalgesia, epidural, and/or patient-controlled analgesia, cryoanalgesia was associated with a 3.3 mg OME/kg reduction in opioid use (P < 0.001). Median length of stay (LOS) was shorter in cryoanalgesia patients: 3.1 d (IQR 2.3-3.4), versus 5.1 d (IQR 4.3-5.4), P < 0.001. Complications within 90 d were similar between groups. CONCLUSIONS: Cryoanalgesia is an effective adjunctive pain control modality for patients undergoing MIRPE. Use of cryoanalgesia was associated with lower postoperative opioid requirements and shorter LOS, without increased short-term complications, and should be considered for enhanced recovery after MIRPE.

The role of software in quality assurance for indirect digital intraoral imaging.

OBJECTIVES: The aim of this study was to evaluate inherent image quality and the effects of software changes on image quality by using photostimulable phosphor (PSP) plates. STUDY DESIGN: Six new DIGORA Optime PSP plates (Soredex/Orion Corp., Helsinki, Finland) were used to assess inherent image quality and the effect of software settings on image quality. Images of a radiographic phantom were exposed to evaluate dynamic range, spatial resolution, and contrast resolution. Varying sharpness filters and gamma values were adjusted to assess their effects on these parameters. RESULTS: Dynamic range was not affected by software settings. Spatial resolution varied among the raw (i.e., minimally processed) images and increased maximally with application of a sharpness filter of 30. Contrast resolution varied among the plates for the raw images. The gamma value of 0.8 was most consistent at increasing the detection of contrast wells. CONCLUSIONS: The findings of our study suggest that the sharpness filter 30 and gamma value of 0.8 may increase the spatial and contrast resolutions of DIGORA Optime PSP images when applied during the scanning process. However, this increase was small. Our results also establish that software manipulation should not be used in an attempt to compensate for data that are not present in the image.

Cdc48/VCP and Endocytosis Regulate TDP-43 and FUS Toxicity and Turnover.

Amyotrophic lateral sclerosis (ALS) is a fatal motor neuron degenerative disease. TDP-43 (TAR DNA-binding protein 43) and FUS (fused in sarcoma) are aggregation-prone RNA-binding proteins that in ALS can mislocalize to the cytoplasm of affected motor neuron cells, often forming cytoplasmic aggregates in the process. Such mislocalization and aggregation are implicated in ALS pathology, though the mechanism(s) of TDP-43 and FUS cytoplasmic toxicity remains unclear. Recently, we determined that the endocytic function aids the turnover (i.e., protein degradation) of TDP-43 and reduces TDP-43 toxicity. Here, we identified that Cdc48 and Ubx3, a Cdc48 cofactor implicated in endocytic function, regulates the turnover and toxicity of TDP-43 and FUS expressed in Saccharomyces cerevisiae Cdc48 physically interacts and colocalizes with TDP-43, as does VCP, in ALS patient tissue. In yeast, FUS toxicity also depends strongly on endocytic function but not on autophagy under normal conditions. FUS expression also impairs endocytic function, as previously observed with TDP-43. Taken together, our data identify a role for Cdc48/VCP and endocytic function in regulating TDP-43 and FUS toxicity and turnover. Furthermore, endocytic dysfunction may be a common defect affecting the cytoplasmic clearance of ALS aggregation-prone proteins and may represent a novel therapeutic target of promise.

Postprocessing of all-zirconia restorations in digital dental radiographs: a quality assurance predicament.

OBJECTIVES: The aim of this study was to describe a quality assurance issue, that is, the production of nondiagnostic high-contrast radiographs when imaging teeth restored with all-zirconia crowns on bitewing radiographs. STUDY DESIGN: All-zirconia crowns were imaged with DIGORA Optime photostimulable phosphor (PSP) plates (Soredex/Orion Corp., Helsinki, Finland). To assess the differences in software processing, the PSP plates were scanned into third-party software as well as directly into the twain and native software provided by the manufacturer. Gamma correction, histogram stretch, and scanner resolution settings were adjusted. Vertical bitewings were acquired to increase anatomic coverage. RESULTS: Scanning into third-party software or directly into the twain and native software did not improve contrast. Shifting the lower limit of the histogram stretch to 3 with a gamma correction of 2 resolved the problem. Neither scanner resolution setting nor vertical bitewings improved contrast. CONCLUSIONS: The nondiagnostic high-contrast radiographs result from imaging software not effectively displaying the available gray scale. The software processing error appears to be initiated by the high-attenuation characteristics of zirconia. Consequently, radiographs with a high ratio of zirconia crown to normal anatomy are particularly susceptible.

Predoctoral and Postdoctoral Education on Cone-Beam Computed Tomography.

OBJECTIVES: As the use of cone beam computed tomography (CBCT) in dentistry continues to grow, questions related to appropriate radiation safety, training, and interpretation arise. Recognizing this need, the American Dental Association published an advisory statement for the safe use of CBCT in dentistry and recommended that guidelines for appropriate training be established. The purpose of this study was to assess radiation safety concerns related to CBCT and identify voids in current education on CBCT for the predoctoral dental curriculum and continuing dental education. METHODS: A survey was mailed to general practitioners, oral surgeons, and periodontists in the Georgia Dental Association (n = 415). RESULTS: One hundred twenty-one surveys were received for a response rate of 29%. Sixty-eight percent of practitioners reported using CBCT, with 89% having used it for over 2 years. Few (12.4%) had experience with CBCT in dental school. Interest in continuing dental education on CBCT was reported at 59.8% and 43.6% for current users and nonusers of CBCT, respectively. Approximately 50% reported using precautionary radiation safety measures, and the methods used were varied. CONCLUSIONS: Although a higher survey return rate would allow for stronger evidence, this project identified some areas of education voids including radiation safety and the factors that contribute to patient dose; CBCT basics including instruction on the limitations of CBCT; CBCT anatomy and pathology with additional time dedicated to the paranasal sinuses; and interpretation.

Fish scale artefact on an intraoral imaging receptor.

OBJECTIVES: To describe an artefact, termed the fish scale artefact, present on an intraoral imaging receptor. METHODS: Thirty brand new DIGORA Optime photostimulable phosphor (PSP) plates (Soredex/Orion Corp., Helsinki, Finland) were imaged using the dental digital quality assurance radiographic phantom (Dental Imaging Consultants LLC, San Antonio, TX). All PSP plates were scanned at the same spatial resolution (dpi) using the high resolution mode. Two evaluators assessed all 30 plates. Each evaluator assessed the 30 PSP plates separately for purposes of establishing interrater reliability, and then together in order to obtain the gold standard result. RESULTS: The fish scale artefact was detected on 46.7% of the PSP plates. The kappa coefficient for interrater reliability was 0.86 [95% CI (0.69-1.00)], indicating excellent interrater reliability. For Evaluator 1, sensitivity was 0.85 [95% CI (0.55-0.98)]; specificity was 0.94 [CI (0.71-1.00)] and overall accuracy was 0.90 [95% CI (0.73-0.98)]. For Evaluator 2, sensitivity was 1.00 [95% CI (0.75-1.00)]; specificity was 0.94 [CI (0.71-1.00)] and overall accuracy was 0.97 [95% CI (0.83-1.00)]. These results indicate excellent agreement with the gold standard for both evaluators. CONCLUSIONS: Utilizing a comprehensive quality assurance protocol, we identified a fish scale artefact inherent to the image receptor. Additional research is needed to determine if the artefact remains static over time or if it increases over time. Likewise, research to determine the potential sources contributing to an increase in the artefact is needed.

Perception versus reality-findings from a phosphor plate quality assurance study.

OBJECTIVE: The aim of the study was to evaluate the image quality of a photostimulable phosphor (PSP) plate system to determine if image degradation has occurred after a number of clinical uses. STUDY DESIGN: Twenty DIGORA Optime PSP plates (Soredex Orion Corp., Helsinki, Finland) were imaged throughout clinical use. Image quality was assessed by using spatial and contrast resolution through the use of the dental radiographic phantom designed for the Nationwide Evaluation of X-Ray Trends surveys of 1993 and 1999. Spatial resolution was summarized in line pairs per millimeter. The paired t test was used to analyze the contrast wells. The contrast-to-noise ratio (CNR) was calculated to determine the signal-to-noise ratio as another measure of contrast. Descriptive statistics were used to summarize the CNR ratios. RESULTS: Spatial resolution decreased after 48 clinical uses. No significant differences were found for the pairwise comparisons of the contrast wells. No CNR varied by more than two-tenths' value difference. CONCLUSIONS: Digora Optime PSP plates displayed unaffected image quality up to 48 clinical uses. Additional studies are needed to confirm these results and to establish guidelines for appropriate replacement intervals for PSP plates.

Cone-beam CT analysis of patients with obstructive sleep apnea compared to normal controls.

PURPOSE: To evaluate the upper airway dimensions of obstructive sleep apnea (OSA) and control subjects using a cone-beam computed tomography (CBCT) unit commonly applied in clinical practice in order to assess airway dimensions in the same fashion as that routinely employed in a clinical setting. MATERIALS AND METHODS: This was a retrospective analysis utilizing existing CBCT scans to evaluate the dimensions of the upper airway in OSA and control subjects. The CBCT data of sixteen OSA and sixteen control subjects were compared. The average area, average volume, total volume, and total length of the upper airway were computed. Width and anterior-posterior (AP) measurements were obtained on the smallest axial slice. RESULTS: OSA subjects had a significantly smaller average airway area, average airway volume, total airway volume, and mean airway width. OSA subjects had a significantly larger airway length measurement. The mean A-P distance was not significantly different between groups. CONCLUSION: OSA subjects have a smaller upper airway compared to controls with the exception of airway length. The lack of a significant difference in the mean A-P distance may indicate that patient position during imaging (upright vs. supine) can affect this measurement. Comparison of this study with a future prospective study design will allow for validation of these results.