Effect of ultra-low doses, ASIR and MBIR on density and noise levels of MDCT images of dental implant sites.

OBJECTIVES: Differences in noise and density values in MDCT images obtained using ultra-low doses with FBP, ASIR, and MBIR may possibly affect implant site density analysis. The aim of this study was to compare density and noise measurements recorded from dental implant sites using ultra-low doses combined with FBP, ASIR, and MBIR. METHODS: Cadavers were scanned using a standard protocol and four low-dose protocols. Scans were reconstructed using FBP, ASIR-50, ASIR-100, and MBIR, and either a bone or standard reconstruction kernel. Density (mean Hounsfield units [HUs]) of alveolar bone and noise levels (mean standard deviation of HUs) was recorded from all datasets and measurements were compared by paired t tests and two-way ANOVA with repeated measures. RESULTS: Significant differences in density and noise were found between the reference dose/FBP protocol and almost all test combinations. Maximum mean differences in HU were 178.35 (bone kernel) and 273.74 (standard kernel), and in noise, were 243.73 (bone kernel) and 153.88 (standard kernel). CONCLUSIONS: Decreasing radiation dose increased density and noise regardless of reconstruction technique and kernel. The effect of reconstruction technique on density and noise depends on the reconstruction kernel used. KEY POINTS: • Ultra-low-dose MDCT protocols allowed more than 90 % reductions in dose. • Decreasing the dose generally increased density and noise. • Effect of IRT on density and noise varies with reconstruction kernel. • Accuracy of low-dose protocols for interpretation of bony anatomy not known. • Effect of low doses on accuracy of computer-aided design models unknown.

The validity of different display monitors in the assessment of dental implant site dimensions in cone beam computed tomography images.

OBJECTIVE: To determine if the differing contrast resolution of various LCD monitors affects the reliability or accuracy of measurements of proposed implant sites. MATERIALS AND METHODS: Edentulous areas of human dry skulls were marked with radiopaque markers in order to standardize the plane of the transverse cross-sections of the ridges and path of measurements. The skulls were imaged by a CBCT device and the images stored in proprietary format on the workstation. The data sets were then transferred, with the proprietary reformatting software, to two different laptops using CDs. Transverse cross-sectional images of the ridges were reformatted on all three computers and ridge dimensions were recorded using the linear measurement tool of the proprietary software. Ridge dimensions were recorded directly from the three different monitors by two observers and compared to measurements recorded directly from the bone. The measurement errors and intra- and inter-examiner reliability were calculated for each monitor and compared with each other. RESULTS: Intra- and inter-examiner reliability scores for the measurements recorded from all three devices were very high and ranged between 0.993-0.999. The mean of the absolute errors was 0.55 mm for the workstation, 0.61 mm for laptop 1 and 0.68 mm for laptop 2. The absolute errors were statistically significant for all three monitors (p-value < 0.001), but there was no statistically significant difference between the absolute errors obtained from the three monitors. CONCLUSIONS: No differences in the reliability or accuracy of measurements of implant site dimensions were obtained using color LCD monitors with different contrast resolution capabilities.

Anterior buccal mandibular depression: A descriptive study of CT findings.

Objective: This study aims to report the concurrence of the radiographic features of anterior buccal mandibular depressions (ABMDs) and anterior lingual mandibular depressions (ALMDs) by conventional computed tomography (CT) and cone beam CT scans. We also assess the effect of ABMDs and ALMDs on dental implant sites. Methods: A retrospective review of CT scans of the mandibles with ABMDs was conducted to assess the morphology, site, presence of foramina, ALMDs, and the integrity of the cortical plate. The superoinferior width of ABMD, the buccolingual depth, and mesiodistal length were measured and compared with the thickness of the cortical plate at the depression to the area superior to it. Results: Thirty-seven patients with 74 ABMDs were included in this study. All observed ABMDs occurred bilaterally, and ALMDs with ABMDs occurred in 13 sites (17.56%). In 20 (54%) cases, at least one foramen was noted. The buccal cortical bone was intact in all cases. The contents of ABMDs were found to be fatty. On an average, their superoinferior width was 7.1 mm, buccolingual depth 1.67 mm, and mesiodistal length 18.8 mm. The average buccal cortical bone plate thickness at the ABMD was 1.23 mm (range 0.4-1.9 mm), while the average buccal cortical bone plate thickness coronal to the ABMD was 1.34 mm (range 0.7-2.2 mm). The average buccolingual dimension of the mandible was 8.72 mm (range 4.15-13.4 mm) at ABMD sites without ALMD and 4.6 mm with ALMD (range 1.8-8 mm). Conclusion: When ALMD occurs in the presence of ABMD, the amount of bone available for implant placement is greatly reduced.

The dilemma of juvenile fibrous dysplasia versus chronic osteomyelitis of the posterior mandible: A case report.

The clinical and radiographic dilemma of fibrous dysplasia versus osteomyelitis is highlighted in this case of a 4-year-old girl with a bony hard swelling in mandibular body and ramus. Rather than relying on histopathological appearance alone, dental professionals should be familiar with the radiographic differences between the two conditions.

Sialolipoma of the Floor of the Mouth with Immunohistological Analysis.

Lipomas are relatively rare in the head and neck, and sialolipoma was described as an entity about 20 years ago as lipoma that entraps salivary gland tissue. Less than 10 cases have been described in the floor of the mouth not related to the major salivary glands. Here, we report a case of sialolipoma affecting the floor of the mouth in a 47-year-old patient and reviewed the clinical, histologic, and immunohistochemical characteristics of the lesion.

Bilateral Anterior Lingual Depression in the Mandible: Cone Beam Computed Tomography Case Report and Review of the Literature.

The mandibular anterior lingual depression is an uncommon anatomical variant. It is difficult to be detected in conventional 2D plain radiographs representing a diagnostic challenge. In this report, we describe a patient who presented to the dental clinic for the extraction of impacted third molars. Upon cone beam computed tomography (CBCT) examination of the mandible, it was incidentally noted that he had bilateral anterior lingual depressions in his mandible. The presence of anterior lingual depressions is uncommon and to be found bilateral is rare. This bone topography represents a challenge for the oral surgeon during implant placement with an increased risk of complications. The incidental finding was documented in the patient's dental record for future implications in case an implant placement was needed.

Validity of linear measurements of the jaws using ultralow-dose MDCT and the iterative techniques of ASIR and MBIR.

PURPOSE: To assess the comparability of linear measurements of dental implant sites recorded from multidetector computed tomography (MDCT) images obtained using standard-dose filtered backprojection (FBP) technique with those from various ultralow doses combined with FBP, adaptive statistical iterative reconstruction (ASIR), and model-based iterative reconstruction (MBIR) techniques. The results of the study may contribute to MDCT dose optimization for dental implant site imaging. METHODS: MDCT scans of two cadavers were acquired using a standard reference protocol and four ultralow-dose test protocols (TP). The volume CT dose index of the different dose protocols ranged from a maximum of 30.48-36.71 mGy to a minimum of 0.44-0.53 mGy. All scans were reconstructed using FBP, ASIR-50, ASIR-100, and MBIR, and either a bone or standard reconstruction kernel. Linear measurements were recorded from standardized images of the jaws by two examiners. Intra- and inter-examiner reliability of the measurements were analyzed using Cronbach's alpha and inter-item correlation. Agreement between the measurements obtained with the reference-dose/FBP protocol and each of the test protocols was determined with Bland-Altman plots and linear regression. Statistical significance was set at a P-value of 0.05. RESULTS: No systematic variation was found between the linear measurements obtained with the reference protocol and the other imaging protocols. The only exceptions were TP3/ASIR-50 (bone kernel) and TP4/ASIR-100 (bone and standard kernels). The mean measurement differences between these three protocols and the reference protocol were within ±0.1 mm, with the 95 % confidence interval limits being within the range of ±1.15 mm. CONCLUSIONS: A nearly 97.5 % reduction in dose did not significantly affect the height and width measurements of edentulous jaws regardless of the reconstruction algorithm used.

Epithelioid Osteosarcoma of the Maxilla: A Case Report and Review of the Literature.

Epithelioid osteosarcoma is an uncommon variant; only 4 cases have been reported in the jaw area, 2 of which were in the maxilla. A 22-year-old woman, in the eighth month of pregnancy, presented to the oral surgery clinic with a mass in the right maxilla that had rapidly expanded over the past 3 months. Computed tomography scans showed an ill-defined sclerotic destructive lesion that formed bone matrix in its soft tissue extension. Microscopic examination of the lesion revealed malignant epithelioid cells with osteoid deposits. The tumor cells were shown to have pale cytoplasm, vesicular nuclei, and prominent nucleoli and to undergo frequent mitosis. In addition, the tumor was positive for epithelial membrane antigen and vimentin and negative for AE1/AE3, Melan-A, CD30, synaptophysin, NSE, CD45, CD99, desmin, and myogenin. The final diagnosis was epithelioid osteosarcoma, which is a rare aggressive variant of osteosarcoma. Few cases of epithelioid osteosarcoma have been reported in the literature, and more studies are required to determine the clinical behavior of this tumor.

A One-Day Dental Faculty Workshop in Writing Multiple-Choice Questions: An Impact Evaluation.

Long training workshops on the writing of exam questions have been shown to be effective; however, the effectiveness of short workshops needs to be demonstrated. The aim of this study was to evaluate the impact of a one-day, seven-hour faculty development workshop at the College of Dentistry, King Saud University, Saudi Arabia, on the quality of multiple-choice questions (MCQs). Kirkpatrick's four-level evaluation model was used. Participants' satisfaction (Kirkpatrick's Level 1) was evaluated with a post-workshop questionnaire. A quasi-experimental, randomized separate sample, pretest-posttest design was used to assess the learning effect (Kirkpatrick's Level 2). To evaluate transfer of learning to practice (Kirkpatrick's Level 3), MCQs created by ten faculty members as a result of the training were assessed. To assess Kirkpatrick's Level 4 regarding institutional change, interviews with three key leaders of the school were conducted, coded, and analyzed. A total of 72 course directors were invited to and attended some part of the workshop; all 52 who attended the entire workshop completed the satisfaction form; and 22 of the 36 participants in the experimental group completed the posttest. The results showed that all 52 participants were highly satisfied with the workshop, and significant positive changes were found in the faculty members' knowledge and the quality of their MCQs with effect sizes of 0.7 and 0.28, respectively. At the institutional level, the interviews demonstrated positive structural changes in the school's assessment system. Overall, this one-day item-writing faculty workshop resulted in positive changes at all four of Kirkpatrick's levels; these effects suggest that even a short training session can improve a dental school's assessment of its students.

Prevalence of carotid calcification detected on panoramic radiographs in a Saudi population from a training institute in Central Saudi Arabia.

OBJECTIVE: To determine the prevalence of carotid artery calcification as detected on panoramic radiographs in a Saudi population. METHODS: This cross sectional study was conducted at the College of Dentistry, King Saud University, Saudi Arabia between March 2008 and January 2009. Five hundred and fifty-five panoramic radiographs of Saudi patients aged 30 years and above was collected from the patient charts. The panoramic radiographs were examined by 3 trained and calibrated examiners to detect any carotid artery calcification. RESULTS: Carotid artery calcification was noted in 28 (5%) of the 555 radiographs. Among these, 21 images were obtained from men (3.75%) and 7 from women (1.25%). CONCLUSION: Dentists should be aware of the techniques to detect carotid artery calcification on the widely used panoramic radiographs. Consequently, information on a life-threatening condition could be provided to the patient, and a precautionary treatment could be suggested.

Postgraduate specialties interest, career choices and qualifications earned by male dentists graduated from King Saud University.

OBJECTIVES: To study the career development of male graduates of King Saud University (KSU), College of Dentistry in terms of pursuit of postgraduate dental education, higher degrees or Board Certification, choice of universities and countries of study, and place of work after qualification. METHODS: A questionnaire survey was carried out through face to face or telephone interview among 666 KSU graduates of 1982-2004. RESULTS: 80% (532 graduates) response rate. (77%) finished postgraduate dental education. 17% specialized in Prosthodontics, 16% in Saudi Board Advanced Restorative Dentistry, 14% in Advanced General Dentistry, 10.5% in Orthodontics, 10% in Oral and Maxillofacial Surgery, 8.3% in Pediatric Dentistry, 7.7% in Endodontics, 6% in Periodontics, 5.5% in Operative Dentistry, 5% in other Specialties. 61% had a Master's degree and 16% had a Doctorate degree. 23% had Board Certificates and 8% had a Fellowship Certificate. (78%) are working in the government, 15% at the university and 6% in private, and 19% in administrative positions. CONCLUSION: Most of the dental graduates were motivated and eager to continue their postgraduate education to get either clinical specialty or academic degrees from nationally and internationally well recognized and known Universities and programs.