Comparing different planimetric methods on volumetric estimations by using cone beam computed tomography.

PURPOSE: The purpose of this study was to compare the accuracy of the planimetric methods on volume estimations by using cone beam computed tomography (CBCT). MATERIALS AND METHODS: Thirty-one prepared intraosseous bone defects from thirteen bovine femur condyles were scanned with CBCT. The defect volumes were estimated by point counting (PC), manual segmentation (MS) and semiautomatic segmentation (SAS) methods at 0.3-mm section thickness without any intersection gap. The estimated volumes were compared with the results of the Archimedes' method. The planimetric methods were analyzed using a Friedman's two-way analysis of variance test. RESULTS: The estimated volumes of MS and SAS methods were compatible with the volumes of Archimedes' method (p = 0.768, p = 0.140, respectively), but the volumes from the PC method were not compatible with Archimedes' method (p < 0.001). CONCLUSION: SAS was approximately 2.5 times faster than MS. Both MS and SAS are valid methods for volume estimation; however, SAS may be preferred due to its practicability.

The effect of slice thickness on the assessment of bone defect volumes by the Cavalieri principle using cone beam computed tomography.

The purpose of this study was to investigate the possible effects of section thickness on volume estimations obtained by cone beam computed tomography. Intraosseal cavities representing bone defects on vestibular sides of the two dry sheep mandibles were scanned by a cone beam computed tomography system. Consecutive sections at 0.2, 0.6, 1, 1.4, and 2.2 mm thickness were used to estimate the volumes of the cavities using the Cavalieri principle of stereological methods. Estimated volumes are then compared with the volumes obtained by the Archimedean principle. In 0.2-, 0.6-, and 1-mm-thick slices, the volumes estimated by the Cavalieri principle did not differ from the volumes by the Archimedean principle (p > 0.05). The 0.2 mm slice-thickness group had the highest asymptotic significance value (p = 0.6). Although the thinnest slice appears to provide the most accurate values, slice thickness up to 1 mm can be chosen for volume calculations on CBCT images.

Mesiodistal tooth dimensions and anterior and overall Bolton ratios evaluated by cone beam computed tomography.

AIM: The mesiodistal widths of the maxillary and mandibular teeth and anterior and overall tooth size ratios were measured by CBCT and conventional orthodontic plaster methods, compared, and correlation coefficients for both methods determined. MATERIAL AND METHODS: The records of 26 patients (14 males and 12 females) between the ages of 18 and 28 years were randomly selected from the archives of the Oral Diagnosis, Radiology and Orthodontic Departments at the Karadeniz Technical University. The mesiodistal diameters of the maxillary and mandibular permanent teeth from first molar to first molar were measured on the patient's plaster models and also on CBCT arch renditions. Anterior and overall Bolton ratios were calculated for each method. Comparisons were performed using Pearson's correlation coefficient (PCC). RESULTS: The measurements of the mesiodistal widths of most maxillary and mandibular teeth were similar and consistent between the conventional and CBCT methods. PCC values ranged from 0.637 (mandibular right second premolar) to 0.916 (maxillary right canine). PCC values for anterior and overall ratios were 0.756 and 0.781, respectively, indicating that correlations between conventional and CBCT methods were acceptable. CONCLUSION: Dental measurements and anterior and overall Bolton ratios calculated on CBCT showed acceptable PCC values indicating that CBCT measurements could be used instead of those obtained from conventional plaster models.

Trabecular structural changes in the mandibular condyle caused by degenerative osteoarthritis: a comparative study by cone-beam computed tomography imaging.

OBJECTIVES: Temporomandibular osteoarthritis causes pain and loss of function. In advanced cases, it may also result in destruction of joint cartilage surfaces and bone structure. METHODS: This study was performed to examine the potential changes in the condylar trabecular bone structure in patients with temporomandibular osteoarthritis. Condylar trabecular structures were compared between 35 healthy patients and 35 patients with temporomandibular osteoarthritis by a box-counting method using fractal dimensional analysis on cone-beam computed tomography images. RESULTS: The average fractal dimensions of patients with temporomandibular osteoarthritis and healthy patients were 1.18 and 1.23, respectively. This difference was statistically significant (p ≤ 0.05). CONCLUSIONS: Our results add to the existing preliminary knowledge regarding the osteoporotic changes that occur in the trabecular structure under the subchondral bone, which is normally not seen on radiographic images, as well as the destruction and remodeling that occur on the condyle surface, which is visible on radiographic images.

Mandibular asymmetry in different occlusion patterns.

OBJECTIVE: To investigate the effects of different occlusion types on the mandibular asymmetry in young individuals. MATERIALS AND METHODS: Mandibular asymmetry measurements were performed on the panoramic radiographs of 189 subjects (104 females and 85 males; age range, 11-15 years), with different occlusion patterns. The subjects were divided into five groups according to the occlusion types, namely, Angle Class I (Cl I), Class II division 1 (Cl II/1), Class II division 2 (Cl II/2), Class III (Cl III), and normal occlusions. The Kruskal-Wallis test was used to determine the possible statistically significant differences between the groups for condyle, ramus, and condyle-plus-ramus asymmetry index measurements. Identified differences between groups were further analyzed using the Mann-Whitney U-test at the 95% confidence interval (P<.05). RESULTS: There were no statistically significant differences between male and female subjects. The Kruskal-Wallis test showed that the occlusion type had a significant effect on the condylar asymmetry. In Cl II/1 cases, condylar asymmetry values were significantly different from the values of Cl II/2 and Cl III malocclusion and normal occlusion types. The normal occlusion control group was significantly different from those of Cl II/1 and the Cl I malocclusion groups. CONCLUSION: Cl II/1 malocclusion has a significant effect on the condylar asymmetry index when compared to Cl II/2 and Cl III malocclusion and normal occlusion types. However, the mean condylar asymmetry index value in Cl II/1 malocclusion was not different from Cl I malocclusion.

Dens invaginatus on a geminated tooth: a case report.

AIM: To present a case of a concomitant occurrence of dens invaginatus (DI) and gemination in a mandibular left lateral incisor. BACKGROUND: DI is a developmental anomaly resulting from the invagination of a portion of a crown in the enamel organ stage of odontogenesis. It is commonly found in the maxillary lateral incisors but also occurs in the central incisors, premolars, canines, and molars in descending order of frequency. The occurrence of DI in the mandible is extremely rare. Gemination results from one tooth bud attempting to split into two. Geminated teeth present with a single root structure and rarely occur in mandibular teeth. REPORT: A 13-year-old girl presented with a chief complaint of spontaneous nocturnal pain in the mandibular left lateral incisor tooth. Intraoral examination revealed the tooth was enlarged with a notch on the incisal edge extending to the coronal 1/3 of the crown. The radiological examination revealed a Type 2 DI in a Type I geminated mandibular left lateral incisor. SUMMARY: DI is clinically significant due to the possibility of the pulpal involvement; pulpitis, necrotic pulps, and chronic periapical lesions are often associated with this anomaly without clinical symptoms. Clinicians should be mindful of the possibility of DI when a tooth presents pulpitis without history of trauma or caries and examine the suspicious tooth and the periodontium radiographically.

Volumetric analysis of the mandibular condyle using cone beam computed tomography.

OBJECTIVE: The aim was to determine the accuracy of volumetric analysis of the mandibular condyle using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: Five dry mandibles containing 9 condyles were used. CBCT scans of the mandibles and an impression of each condylar area were taken. The physical volumes of the condyles were calculated as the gold standard using the water displacement technique. After isolating, the condylar volume was sectioned in the sagittal plane, and 0.3mm thick sections with 0.9mm intervals were obtained from 3D reconstructions. Using the Cavalieri principle, the volume of each condyle was estimated from the CBCT images by three observers. The accuracy of the CBCT volume measurements and the relation agreements between the results of the three observers were assessed using the Wilcoxon Signed Rank test and Pearson correlation test. The level of statistical significance was set at 0.05. RESULTS: The results of the Pearson correlation showed that there were highly significant positive correlations between the observers' measurements. According to the results of the Wilcoxon Signed Rank test comparing the physical and observers' measurements, there were no statistically significant differences (p>0.05). CONCLUSION: The Cavalieri principle, used in conjunction with a planimetry method, is a valid and effective method for volume estimation of the mandibular condyle on CBCT images.

Conventional frontal radiographs compared with frontal radiographs obtained from cone beam computed tomography.

AIM: To test the hypothesis that there is no difference between measurements performed on conventional frontal radiographs (FRs) and those performed on FRs obtained from cone beam computed tomography (CBCT) scans. MATERIALS AND METHODS: This study consisted of conventional FRs and CBCT-constructed FRs obtained from 30 young adult patients. Twenty-three landmarks were identified on both types of cephalometric radiographs. Twenty-one widely used cephalometric variables (14 linear distances, 4 angles, and 3 ratios) were calculated. Paired t-tests were performed to compare the means of corresponding measurements on two cephalometric radiographs of the same patient. RESULTS: Reproducibility of measurements ranged from 0.85 to 0.99 for CBCT-constructed FRs, and from 0.78 to 0.96 for conventional FRs. A statistically significant difference was observed between conventional FRs and CBCT-constructed FRs for all linear measurements (eurR-eurL, loR-loL, moR-moL, zygR-zygL, lapR-lapL, mxR-mxL, maR-maL, umR-umL, lmR-lmL, agR-agL, me-ans) (P < .05), except for the ans-cr measurement (P > .05). However, no statistically significant differences were noted between conventional FRs and CBCT-constructed FRs for ratios and angular measurements (P > .05). CONCLUSIONS: The hypothesis was rejected. A difference has been noted between measurements performed on conventional FRs and those performed on CBCT-constructed FRs, particularly in terms of linear measurements.

An in vitro comparison of diagnostic abilities of conventional radiography, storage phosphor, and cone beam computed tomography to determine occlusal and approximal caries.

AIM: The aim of this study was to compare conventional radiography, storage phosphor plate, and cone beam computed tomography for in vitro determination of occlusal and approximal caries. METHODS: A total of 72 extracted human premolar and molar teeth were selected. Teeth were radiographed with conventional intraoral radiography, a storage phosphor plate system, and cone beam computed tomography and evaluated by two observers. The teeth were then separated and examined with a stereomicroscope and a scanner at approximately 8×magnification. RESULTS: CBCT was statistically superior to conventional radiography and phosphor plate for determining occlusal caries. No significant difference from CBCT, conventional radiography and the phosphor plate system for determining approximal caries was found. CONCLUSION: The CBCT system may be used as an auxiliary method for the detection of caries.