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Unusually large erupted complex odontoma: A rare case report.

Shivanand B BAGEWADI ; Rahul KUKREJA ; Gundareddy N SUMA ; Bhawna YADAV ; Havi SHARMA

Imaging Science in Dentistry.2015;45(1):49-54. doi:10.5624/isd.2015.45.1.49

Odontomas are nonaggressive, hamartomatous developmental malformations composed of mature tooth substances and may be compound or complex depending on the extent of morphodifferentiation or on their resemblance to normal teeth. Among them, complex odontomas are relatively rare tumors. They are usually asymptomatic in nature. Occasionally, these tumors become large, causing bone expansion followed by facial asymmetry. Odontoma eruptions are uncommon, and thus far, very few cases of erupted complex odontomas have been reported in the literature. Here, we report the case of an unusually large, painless, complex odontoma located in the right posterior mandible.
Facial Asymmetry ; Mandible ; Odontogenic Tumors ; Odontoma* ; Tooth

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Accuracy and reliability of stitched cone-beam computed tomography images.

Nicholas EGBERT ; David R CAGNA ; Swati AHUJA ; Russell A WICKS

Imaging Science in Dentistry.2015;45(1):41-47. doi:10.5624/isd.2015.45.1.41

PURPOSE: This study was performed to evaluate the linear distance accuracy and reliability of stitched small field of view (FOV) cone-beam computed tomography (CBCT) reconstructed images for the fabrication of implant surgical guides. MATERIALS AND METHODS: Three gutta percha points were fixed on the inferior border of a cadaveric mandible to serve as control reference points. Ten additional gutta percha points, representing fiduciary markers, were scattered on the buccal and lingual cortices at the level of the proposed complete denture flange. A digital caliper was used to measure the distance between the reference points and fiduciary markers, which represented the anatomic linear dimension. The mandible was scanned using small FOV CBCT, and the images were then reconstructed and stitched using the manufacturer's imaging software. The same measurements were then taken with the CBCT software. RESULTS: The anatomic linear dimension measurements and stitched small FOV CBCT measurements were statistically evaluated for linear accuracy. The mean difference between the anatomic linear dimension measurements and the stitched small FOV CBCT measurements was found to be 0.34 mm with a 95% confidence interval of +0.24 - +0.44 mm and a mean standard deviation of 0.30 mm. The difference between the control and the stitched small FOV CBCT measurements was insignificant within the parameters defined by this study. CONCLUSION: The proven accuracy of stitched small FOV CBCT data sets may allow image-guided fabrication of implant surgical stents from such data sets.
Cadaver ; Computer-Aided Design ; Cone-Beam Computed Tomography* ; Dataset ; Dental Implants ; Denture, Complete ; Gutta-Percha ; Mandible ; Stents

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Intravenous contrast media application using cone-beam computed tomography in a rabbit model.

Min Sung KIM ; Bok Yeol KIM ; Hwa Young CHOI ; Yoon Joo CHOI ; Song Hee OH ; Ju Hee KANG ; Sae Rom LEE ; Ju Han KANG ; Gyu Tae KIM ; Yong Suk CHOI ; Eui Hwan HWANG

Imaging Science in Dentistry.2015;45(1):31-39. doi:10.5624/isd.2015.45.1.31

PURPOSE: This study was performed to evaluate the feasibility of visualizing soft tissue lesions and vascular structures using contrast-enhanced cone-beam computed tomography (CE-CBCT) after the intravenous administration of a contrast medium in an animal model. MATERIALS AND METHODS: CBCT was performed on six rabbits after a contrast medium was administered using an injection dose of 2 mL/kg body weight and an injection rate of 1 mL/s via the ear vein or femoral vein under general anesthesia. Artificial soft tissue lesions were created through the transplantation of autologous fatty tissue into the salivary gland. Volume rendering reconstruction, maximum intensity projection, and multiplanar reconstruction images were reconstructed and evaluated in order to visualize soft tissue contrast and vascular structures. RESULTS: The contrast enhancement of soft tissue was possible using all contrast medium injection parameters. An adequate contrast medium injection parameter for facilitating effective CE-CBCT was a 5-mL injection before exposure combined with a continuous 5-mL injection during scanning. Artificial soft tissue lesions were successfully created in the animals. The CE-CBCT images demonstrated adequate opacification of the soft tissues and vascular structures. CONCLUSION: Despite limited soft tissue resolution, the opacification of vascular structures was observed and artificial soft tissue lesions were visualized with sufficient contrast to the surrounding structures. The vascular structures and soft tissue lesions appeared well delineated in the CE-CBCT images, which was probably due to the superior spatial resolution of CE-CBCT compared to other techniques, such as multislice computed tomography.
Adipose Tissue ; Administration, Intravenous ; Anesthesia, General ; Animals ; Body Weight ; Cone-Beam Computed Tomography* ; Contrast Media* ; Ear ; Femoral Vein ; Models, Animal ; Multidetector Computed Tomography ; Rabbits ; Radiography ; Salivary Glands ; Veins

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Accuracy of virtual models in the assessment of maxillary defects.

Kivanc KAMBUROGLU ; Sebnem KURSUN ; Cenk KILIC ; Tuncer OZEN

Imaging Science in Dentistry.2015;45(1):23-29. doi:10.5624/isd.2015.45.1.23

PURPOSE: This study aimed to assess the reliability of measurements performed on three-dimensional (3D) virtual models of maxillary defects obtained using cone-beam computed tomography (CBCT) and 3D optical scanning. MATERIALS AND METHODS: Mechanical cavities simulating maxillary defects were prepared on the hard palate of nine cadavers. Images were obtained using a CBCT unit at three different fields-of-views (FOVs) and voxel sizes: 1) 60x60 mm FOV, 0.125 mm3 (FOV60); 2) 80x80 mm FOV, 0.160 mm3 (FOV80); and 3) 100x100 mm FOV, 0.250 mm3 (FOV100). Superimposition of the images was performed using software called VRMesh Design. Automated volume measurements were conducted, and differences between surfaces were demonstrated. Silicon impressions obtained from the defects were also scanned with a 3D optical scanner. Virtual models obtained using VRMesh Design were compared with impressions obtained by scanning silicon models. Gold standard volumes of the impression models were then compared with CBCT and 3D scanner measurements. Further, the general linear model was used, and the significance was set to p=0.05. RESULTS: A comparison of the results obtained by the observers and methods revealed the p values to be smaller than 0.05, suggesting that the measurement variations were caused by both methods and observers along with the different cadaver specimens used. Further, the 3D scanner measurements were closer to the gold standard measurements when compared to the CBCT measurements. CONCLUSION: In the assessment of artificially created maxillary defects, the 3D scanner measurements were more accurate than the CBCT measurements.
Cadaver ; Cone-Beam Computed Tomography ; Dimensional Measurement Accuracy ; Linear Models ; Maxillofacial Prosthesis ; Palate, Hard ; Silicones

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Reproducibility of the sella turcica landmark in three dimensions using a sella turcica-specific reference system.

Pisha PITTAYAPAT ; Reinhilde JACOBS ; Guillaume A ODRI ; Karla de Faria VASCONCELOS ; Guy WILLEMS ; Raphael OLSZEWSKI

Imaging Science in Dentistry.2015;45(1):15-22. doi:10.5624/isd.2015.45.1.15

PURPOSE: This study was performed to assess the reproducibility of identifying the sella turcica landmark in a threedimensional (3D) model by using a new sella-specific landmark reference system. MATERIALS AND METHODS: Thirty-two cone-beam computed tomographic scans (3D Accuitomo(R) 170, J. Morita, Kyoto, Japan) were retrospectively collected. The 3D data were exported into the Digital Imaging and Communications in Medicine standard and then imported into the Maxilim(R) software (Medicim NV, Sint-Niklaas, Belgium) to create 3D surface models. Five observers identified four osseous landmarks in order to create the reference frame and then identified two sella landmarks. The x, y, and z coordinates of each landmark were exported. The observations were repeated after four weeks. Statistical analysis was performed using the multiple paired t-test with Bonferroni correction (intraobserver precision: p<0.005, interobserver precision: p<0.0011). RESULTS: The intraobserver mean precision of all landmarks was <1 mm. Significant differences were found when comparing the intraobserver precision of each observer (p<0.005). For the sella landmarks, the intraobserver mean precision ranged from 0.43+/-0.34 mm to 0.51+/-0.46 mm. The intraobserver reproducibility was generally good. The overall interobserver mean precision was <1 mm. Significant differences between each pair of observers for all anatomical landmarks were found (p<0.0011). The interobserver reproducibility of sella landmarks was good, with >50% precision in locating the landmark within 1 mm. CONCLUSION: A newly developed reference system offers high precision and reproducibility for sella turcica identification in a 3D model without being based on two-dimensional images derived from 3D data.
Cephalometry ; Cone-Beam Computed Tomography ; Imaging, Three-Dimensional ; Orthodontics ; Retrospective Studies ; Sella Turcica*

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Volumetric quantification of bone-implant contact using micro-computed tomography analysis based on region-based segmentation.

Sung Won KANG ; Woo Jin LEE ; Soon Chul CHOI ; Sam Sun LEE ; Min Suk HEO ; Kyung Hoe HUH ; Tae Il KIM ; Won Jin YI

Imaging Science in Dentistry.2015;45(1):7-13. doi:10.5624/isd.2015.45.1.7

PURPOSE: We have developed a new method of segmenting the areas of absorbable implants and bone using region-based segmentation of micro-computed tomography (micro-CT) images, which allowed us to quantify volumetric bone-implant contact (VBIC) and volumetric absorption (VA). MATERIALS AND METHODS: The simple threshold technique generally used in micro-CT analysis cannot be used to segment the areas of absorbable implants and bone. Instead, a region-based segmentation method, a region-labeling method, and subsequent morphological operations were successively applied to micro-CT images. The three-dimensional VBIC and VA of the absorbable implant were then calculated over the entire volume of the implant. Two-dimensional (2D) bone-implant contact (BIC) and bone area (BA) were also measured based on the conventional histomorphometric method. RESULTS: VA and VBIC increased significantly with as the healing period increased (p<0.05). VBIC values were significantly correlated with VA values (p<0.05) and with 2D BIC values (p<0.05). CONCLUSION: It is possible to quantify VBIC and VA for absorbable implants using micro-CT analysis using a region-based segmentation method.
Absorbable Implants ; Absorption ; Image Processing, Computer-Assisted ; Osseointegration ; X-Ray Microtomography

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Lateral pterygoid muscle volume and migraine in patients with temporomandibular disorders.

Sergio Lucio Pereira de Castro LOPES ; Andre Luiz Ferreira COSTA ; Thiago de Oliveira GAMBA ; Isadora Luana FLORES ; Adriana Dibo CRUZ ; Li Li MIN

Imaging Science in Dentistry.2015;45(1):1-5. doi:10.5624/isd.2015.45.1.1

PURPOSE: Lateral pterygoid muscle (LPM) plays an important role in jaw movement and has been implicated in Temporomandibular disorders (TMDs). Migraine has been described as a common symptom in patients with TMDs and may be related to muscle hyperactivity. This study aimed to compare LPM volume in individuals with and without migraine, using segmentation of the LPM in magnetic resonance (MR) imaging of the TMJ. MATERIALS AND METHODS: Twenty patients with migraine and 20 volunteers without migraine underwent a clinical examination of the TMJ, according to the Research Diagnostic Criteria for TMDs. MR imaging was performed and the LPM was segmented using the ITK-SNAP 1.4.1 software, which calculates the volume of each segmented structure in voxels per cubic millimeter. The chi-squared test and the Fisher's exact test were used to relate the TMD variables obtained from the MR images and clinical examinations to the presence of migraine. Logistic binary regression was used to determine the importance of each factor for predicting the presence of a migraine headache. RESULTS: Patients with TMDs and migraine tended to have hypertrophy of the LPM (58.7%). In addition, abnormal mandibular movements (61.2%) and disc displacement (70.0%) were found to be the most common signs in patients with TMDs and migraine. CONCLUSION: In patients with TMDs and simultaneous migraine, the LPM tends to be hypertrophic. LPM segmentation on MR imaging may be an alternative method to study this muscle in such patients because the hypertrophic LPM is not always palpable.
Humans ; Hypertrophy ; Jaw ; Magnetic Resonance Imaging ; Migraine Disorders* ; Pterygoid Muscles* ; Temporomandibular Joint ; Temporomandibular Joint Disorders* ; Volunteers

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Development of 3D statistical mandible models for cephalometric measurements.

Sung Goo KIM ; Won Jin YI ; Soon Jung HWANG ; Soon Chul CHOI ; Sam Sun LEE ; Min Suk HEO ; Kyung Hoe HUH ; Tae Il KIM ; Helen HONG ; Ji Hyun YOO

Imaging Science in Dentistry.2012;42(3):175-182. doi:10.5624/isd.2012.42.3.175

PURPOSE: The aim of this study was to provide sex-matched three-dimensional (3D) statistical shape models of the mandible, which would provide cephalometric parameters for 3D treatment planning and cephalometric measurements in orthognathic surgery. MATERIALS AND METHODS: The subjects used to create the 3D shape models of the mandible included 23 males and 23 females. The mandibles were segmented semi-automatically from 3D facial CT images. Each individual mandible shape was reconstructed as a 3D surface model, which was parameterized to establish correspondence between different individual surfaces. The principal component analysis (PCA) applied to all mandible shapes produced a mean model and characteristic models of variation. The cephalometric parameters were measured directly from the mean models to evaluate the 3D shape models. The means of the measured parameters were compared with those from other conventional studies. The male and female 3D statistical mean models were developed from 23 individual mandibles, respectively. RESULTS: The male and female characteristic shapes of variation produced by PCA showed a large variability included in the individual mandibles. The cephalometric measurements from the developed models were very close to those from some conventional studies. CONCLUSION: We described the construction of 3D mandibular shape models and presented the application of the 3D mandibular template in cephalometric measurements. Optimal reference models determined from variations produced by PCA could be used for craniofacial patients with various types of skeletal shape.
Cephalometry ; Female ; Humans ; Imaging, Three-Dimensional ; Male ; Mandible ; Passive Cutaneous Anaphylaxis ; Principal Component Analysis

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Osteoarthritic changes and condylar positioning of the temporomandibular joint in Korean children and adolescents.

Bong Hae CHO ; Yun Hoa JUNG

Imaging Science in Dentistry.2012;42(3):169-174. doi:10.5624/isd.2012.42.3.169

PURPOSE: To investigate the prevalence of osteoarthritic changes and condylar positioning of the temporomandibular joint (TMJ) in Korean children and adolescents with or without temporomandibular disorders (TMDs). MATERIALS AND METHODS: A total of 101 asymptomatic and 181 symptomatic children and adolescents aged 10 to 18 years old were included in the study. Osteoarthritic changes such as flattening, sclerosis, osteophytes, or erosion, and the parasagittal positioning of the condyle were assessed using cone-beam computed tomography (CBCT) images. RESULTS: The overall prevalence of osteoarthritic changes was higher in symptomatic (26.8%) than in asymptomatic adolescents (9.9%) (p<0.05). In the symptomatic group, the frequency was higher in males (33.3%) than in females (23.0%) (p<0.05). Erosion was the most common change for the symptomatic group (15.6%), whereas sclerosis was the most common change for the asymptomatic group (5.4%). Posterior condylar position was more frequently observed in the symptomatic group (p<0.05). Erosion was more common in the samples with TMJ pain or mouth opening limitations as compared to those without them (p<0.05). CONCLUSION: This study showed that osteoarthritic changes in TMJ were common in children and adolescents, with a much higher prevalence in symptomatic patients.
Adolescent ; Aged ; Child ; Cone-Beam Computed Tomography ; Female ; Humans ; Male ; Mouth ; Osteophyte ; Prevalence ; Sclerosis ; Temporomandibular Joint ; Temporomandibular Joint Disorders

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Assessment of radiopacity of restorative composite resins with various target distances and exposure times and a modified aluminum step wedge.

Arash POORSATTAR BEJEH MIR ; Morvarid POORSATTAR BEJEH MIR

Imaging Science in Dentistry.2012;42(3):163-167. doi:10.5624/isd.2012.42.3.163

PURPOSE: ANSI/ADA has established standards for adequate radiopacity. This study was aimed to assess the changes in radiopacity of composite resins according to various tube-target distances and exposure times. MATERIALS AND METHODS: Five 1-mm thick samples of Filtek P60 and Clearfil composite resins were prepared and exposed with six tube-target distance/exposure time setups (i.e., 40 cm, 0.2 seconds; 30 cm, 0.2 seconds; 30 cm, 0.16 seconds, 30 cm, 0.12 seconds; 15 cm, 0.2 seconds; 15 cm, 0.12 seconds) performing at 70 kVp and 7 mA along with a 12-step aluminum stepwedge (1 mm incremental steps) using a PSP digital sensor. Thereafter, the radiopacities measured with Digora for Windows software 2.5 were converted to absorbencies (i.e., A=-log (1-G/255)), where A is the absorbency and G is the measured gray scale). Furthermore, the linear regression model of aluminum thickness and absorbency was developed and used to convert the radiopacity of dental materials to the equivalent aluminum thickness. In addition, all calculations were compared with those obtained from a modified 3-step stepwedge (i.e., using data for the 2nd, 5th, and 8th steps). RESULTS: The radiopacities of the composite resins differed significantly with various setups (p<0.001) and between the materials (p<0.001). The best predicted model was obtained for the 30 cm 0.2 seconds setup (R2=0.999). Data from the reduced modified stepwedge was remarkable and comparable with the 12-step stepwedge. CONCLUSION: Within the limits of the present study, our findings support that various setups might influence the radiopacity of dental materials on digital radiographs.
Aluminum ; Composite Resins ; Dental Materials ; Linear Models ; Radiography, Dental, Digital

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