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.

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.

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.

Management of Large Radicular Lesions Using Decompression: A Case Series and Review of the Literature.

The purpose of this study was to report the clinical efficacy of decompression for 3 cases with large periapical lesions and to review technique details. Three cases with large periapical cystic lesions were treated with decompression after root canal treatment. A traditional decompression technique was used for the first case. After aspiration, mucogingival incision, irrigation, and incisional biopsy, a pediatric endotracheal tube was sutured in place and kept for 3 weeks for lesion debridement. An aspiration/irrigation technique was adopted for the second case. An 18-G needle with a syringe was used to aspirate the cystic lesion. Two needles were then inserted into the lesion; copious saline irrigation was delivered from 1 needle and until clear saline was expressed from the other. For the third case, decompression was accomplished with a surgical catheter that was subsequently replaced with a gutta-percha plug after 1 month. None of the 3 cases underwent complete enucleation and root-end surgery. Healed lesions or lesions in healing were observed after 1 to 2 years. Based on the presented cases and published case reports on decompression, a literature review was provided covering indications, technique details, modification, and prognosis of decompression in endodontics. For large periapical cystic lesions, conservative decompression may be used for certain cases before or in lieu of apical surgery. Decompression enables healing of large, persistent periapical lesions after root canal treatment.

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.

Incidental Finding of a Foreign Object on a Panoramic Radiograph.

This study's purpose was to describe a case involving the discovery of a foreign body in the ear canal of an eight-year-old boy, revealed during a recall evaluation to a dental clinic. A panoramic radiograph revealed a radiopaque object in the area of the external auditory meatus. The patient's mother reported one incidence of reported ear pain that resolved spontaneously, but the patient denied placing any object into his ear both in our clinic and at the time he reported ear pain to his mother. The patient was referred to an otolaryngologist, and the object was removed.

Interdisciplinary treatment of an adult with bilateral cleft lip and palate with missing premaxilla: The prosthodontic perspective.

Conventional orthognathic surgery and orthodontic techniques occasionally fail to completely correct the occlusal relationship and esthetic deficits of patients with cleft lip and palate and severe midface deficiency. Prosthodontic rehabilitation is often required to establish adequate occlusion and provide a more proportional facial appearance. This clinical report describes the interdisciplinary management of an adult with complete bilateral cleft lip and palate who was treated with distraction osteogenesis using a rigid external distraction device for maxillary advancement and his prosthodontic rehabilitation with a dual path removable partial overdenture to develop definitive facial and dental esthetic form.

The effectiveness of a pre-procedural mouthrinse in reducing bacteria on radiographic phosphor plates.

PURPOSE: This study assessed the effectiveness of three antimicrobial mouthrinses in reducing microbial growth on photostimulable phosphor (PSP) plates. MATERIALS AND METHODS: Prior to performing a full-mouth radiographic survey (FMX), subjects were asked to rinse with one of the three test rinses (Listerine®, Decapinol®, or chlorhexidine oral rinse 0.12%) or to refrain from rinsing. Four PSP plates were sampled from each FMX through collection into sterile containers upon exiting the scanner. Flame-sterilized forceps were used to transfer the PSP plates onto blood agar plates (5% sheep blood agar). The blood agar plates were incubated at 37℃ for up to 72 h. An environmental control blood agar plate was incubated with each batch. Additionally, for control, 25 gas-sterilized PSP plates were plated onto blood agar and analyzed. RESULTS: The mean number of bacterial colonies per plate was the lowest in the chlorhexidine group, followed by the Decapinol, Listerine, and the no rinse negative control groups. Only the chlorhexidine and Listerine groups were significantly different (p=0.005). No growth was observed for the 25 gas-sterilized control plates or the environmental control blood agar plates. CONCLUSION: The mean number of bacterial colonies was the lowest in the chlorhexidine group, followed by the Decapinol, Listerine, and the no rinse groups. Nonetheless, a statistically significant difference was found only in the case of Listerine. Additional research is needed to test whether a higher concentration (0.2%) or longer exposure period (two consecutive 30 s rinse periods) would be helpful in reducing PSP plate contamination further with chlorhexidine.

Diagnostic imaging for temporomandibular disorders and orofacial pain.

The focus of this article is diagnostic imaging used for the evaluation of temporomandibular disorders and orofacial pain patients. Imaging modalities discussed include conventional panoramic radiography, panoramic temporomandibular joint imaging mode, cone beam computed tomography, and magnetic resonance imaging. The imaging findings associated with common diseases of the temporomandibular joint are presented and indications for brain imaging are discussed. Advantages and disadvantages of each imaging modality are presented as well as illustrations of the various imaging techniques.

Evaluation of an ameloblastic fibro-odontoma with cone beam computed tomography.

BACKGROUND: The clinical presentation, radiographic features, and histopathological findings of a case of ameloblastic fibro-odontoma are described. The clinical and radiographic presentations of this case are typical of this benign odontogenic tumor. The patient was young and asymptomatic with the exception of the clinical absence of the permanent mandibular left first molar. Treatment consisted of simple enucleation with removal of the primary mandibular left second molar. METHODS: A panoramic image and cone beam computed tomography (CBCT) scan were acquired in order to determine the reason for clinical absence of the permanent mandibular left first molar. The CBCT image proved to be a valuable supplement to the conventional radiographic examination as it provided information not apparent on the 2-dimensional panoramic image. Both the extent of the lesion and its effects on adjacent structures were better delineated with CBCT. Additionally, the presence of calcifications, an important radiographic characteristic of this particular lesion, were visible on CBCT versus the panoramic image. CONCLUSIONS: This case report demonstrates that the CBCT scan provided important management and treatment planning information that was not apparent in the panoramic image.

An evaluation of microbiologic contamination on a phosphor plate system: is weekly gas sterilization enough?

OBJECTIVE: This study was performed to determine: 1) the rate and source of microbiologic contamination of photostimulable phosphor plates (PSP) in a predoctoral clinic; and 2) whether a combination of weekly gas sterilization and barrier protocols can prevent contamination of PSP plates. METHODS: Fifty plates in clinical use and 25 gas-sterilized control plates were selected for examination. The PSP plates were pressed onto blood agar medium and incubated at 37 degrees C. The number, size, distribution, and variety of resulting colonies were noted. To test whether these bacteria could have come from oral sources, 17 colonies were selected for culture on Mitis-Salivarius (M-S) agar. Those colonies that grew on the M-S agar were Gram stained. RESULTS: Twenty-eight test plates (56%) exhibited growth of bacterial colonies on blood agar. Seventeen of those bacterial colonies were selected for growth on M-S agar, and 13 (76.47%) showed growth, 69% of them gram positive. CONCLUSION: Our results indicate reinforcing standard precautions of infection control for intraoral radiography, and that gas sterilization of plates after each day's clinical use is a potential solution.

An evaluation of microbiologic contamination on phosphor plates in a dental school.

OBJECTIVE: The objective of this study was to determine if phosphor plates used in predoctoral clinics are microbiologically contaminated and to identify the source of contamination. STUDY DESIGN: Forty-five of 300 phosphor plates (15%) were randomly selected for examination. The plates were pressed into individual blood agar plates, were incubated using standard techniques at 37 degrees C, and were monitored for 72 hours. The number, size, distribution, and variety of resulting colonies were noted. A representative of each type of colony was selected to be Gram stained using the standard technique. RESULTS: Of the plates, 42.2% were uncontaminated, 57.8% yielded bacterial colonies, and 15.6% of those colonies demonstrated hemolytic growth. The hemolytic growth included combined alpha and beta hemolysis and beta only hemolysis. Six colonies were gram-positive rods and 7 were gram-positive cocci. CONCLUSION: Meticulous infection-control techniques are inevitable and continuous reinforcement and training for staff and students are mandatory. Periodic gas sterilization of phosphor plates may be necessary.

In vitro assessment of cone beam local computed tomography for proximal caries detection.

OBJECTIVES: To compare the accuracy of local computed tomography (LCT) and conventional radiography for proximal caries detection and depth assessment. STUDY DESIGN: An in vitro model was used consisting of 20 extracted posterior teeth with 18 caries lesions. Local computed tomography slices were reconstructed in axial and parasagittal planes from 100 basis projections. Conventional radiographs were also acquired. Eight observers determined the presence and depth of caries lesions. Receiver operating characteristic analysis and weighted kappa statistics were used. RESULTS: Local computed tomography had a mean A(z) score of 0.82 (SD = 0.07) and conventional radiography of 0.79 (SD = 0.08; analysis of variance: P > .05). Interobserver agreement was moderate. The mean kappa for depth assessment was 0.68 (SD = 0.06) for LCT and 0.47 (SD = 0.08) for conventional radiography (analysis of variance: P < .05). Local computed tomography resulted in substantial and conventional radiography in moderate interobserver agreement. CONCLUSIONS: There is no difference between LCT and conventional radiography for proximal caries detection. Local computed tomography was more accurate for assessing caries lesion depth.

The effect of lighting conditions on caries interpretation with a laptop computer in a clinical setting.

OBJECTIVE: To test the null hypothesis of no difference in caries detection in dim, bright, and hooded environments for laptop viewing of intraoral radiographs. STUDY DESIGN: Extracted posterior teeth were imaged with posterior bite wing geometry by using storage phosphor plates. Images were displayed on a laptop computer placed in 3 lighting environments. Six dental students and 6 faculty observers scored the caries status of proximal surfaces. Responses were compared to histologic ground truth by using receiver operating characteristic (ROC) analysis and other measures of accuracy. Performance was also compared to photometer-measured light levels and time spent in observation. RESULTS: ROC A(Z) was significantly higher for faculty using hooded displays (0.87) than in a bright clinical environment (0.79; P = .04). Student performance was highly variable and not significantly different in any of the lighting environments. CONCLUSION: The ability to detect caries by experienced clinicians may be improved by hooding laptop displays in bright clinical environments.