Cone-bean Computed Tomography Images Research Articles

Crown-root angulations of the maxillary anterior teeth according to malocclusions: A cone-beam computed tomography study in Korean population.

To compare crown-root angulations of the permanent maxillary anterior teeth in skeletal Class I, Class II, and Class III Korean malocclusion patients using cone-bean computed tomography (CBCT) images. Sixty CBCT images were collected from orthodontic patients archive based on skeletal Class I (0˚< A point-nasion-B point angle [ANB] < 4˚), Class II (ANB ≥ 4˚), and Class III (ANB ≤ 0˚) to have 20 samples in each group. Mesiodistal crown-root angulation (MDCRA) and labiolingual crown-root angulation (LLCRA) were evaluated after orientation of images. Crown-root angulations were compared among Class I, Class II, and Class III groups and among the maxillary anterior teeth in each group. LLCRAs of the maxillary central incisor and the lateral incisor were significantly lower in Class III group than those in Class I group. However, those of the canine showed no significant differences among groups. MDCRAs of the maxillary anterior teeth did not significantly differ among groups either. Our results suggest that skeletal Class III malocclusion might affect LLCRA of the maxillary incisors, especially the central incisor.

Influence of orthodontic treatment with premolar extraction on the spatial position of maxillary third molars in adult patients: a retrospective cohort cone-bean computed tomography study

BackgroundBased on low-dose radiation Cone-bean computed tomography (CBCT) images, This study aims to establish a space coordinate system, which offers more precise and comparable evaluation on changes of maxillary third molars influenced by orthodontic treatment with premolar extraction in adults. The system suggests promising application prospect in future studies related to CBCT superimposition and evaluation for its feasibility and efficiency.MethodsForty-nine maxillary third molars from 27 patients (mean age, 20.78 years) were included. CBCT images were obtained before and after orthodontic treatment with premolars extracted (mean treatment duration, 31.47 months). The changes in the position, angulation, and rotation of the third molars were evaluated with a space coordinate system using four landmarks: anterior nasal spine (ANS), posterior nasal spine (PNS), left and right orbitales.ResultsAfter orthodontic treatment, the third molars moved forward (adjusted mean, 1.44 mm) (p < 0.001) and downward (adjusted mean, 2.87 mm) (p < 0.001) accompanied by outward rotation of the crowns (adjusted mean, 5.38°) (p = 0.001), while changes in angulation were insignificant.ConclusionsThis was the first study to systematically investigate the spatial position change of maxillary third molars in adult patients who received orthodontic treatment with premolar extraction. During the process, maxillary third molars moved downward and forward accompanied by outward rotation of the crowns. Orthodontists should take tooth movement potential into consideration when making extraction plans.

Evaluation of total bone and cortical bone thickness of the palate for temporary anchorage device insertion

Background/purposeThe palate has become a popular site for the placement of temporary anchorage devices (TADs) owing to its bone quantity and quality. This study aimed to investigate total and cortical bone thicknesses in the whole palate as well as palatal width using a standard grid system and cone-bean computed tomography (CBCT) images. Materials and methodsThe CBCT images of 43 samples were selected. The total bone and cortical bone thicknesses of the palate were surveyed on 64 points per patient. The palatal width was measured. The difference between the age and sex groups was analyzed. ResultsThe total palatal bone thickness in the adult group ranged from 9.85 ± 2.04 to 1.87 ± 0.79 mm. In the adolescent group, we found one-third of the incisor roots in the area 3 mm distal to the incisive foramen and 8 mm lateral to the mid-palatal suture. The cortical bone thickness in adults was significantly thicker in the posterior paramedian area than that in adolescents. ConclusionThe thickest vertical bone is located in the zone 3 mm distal to the incisive foramen and 4–8 mm lateral to the midpalate. The zone 6 mm posterior to the incisive foramen and 2–8 mm lateral to the midpalate exhibited optimal thickness and was away from the incisor roots. This region could be a safe zone for adolescent patients to place TADs. When TADs are to be inserted at the posterior palate, the 2-mm paramedian area should be the first region of choice.

Prevalence and morphology of multiple roots, root canals and C-shaped canals in mandibular premolars from cone-beam computed tomography images in a Thai population

Background/purposeVariations in root and root canal morphology of mandibular premolars of Thais has not been reported, and understanding these variations enhances endodontic success. The purpose was to investigate prevalence and morphology of multiple roots, root canals and C-shaped canals in mandibular premolars in a Thai population from cone-bean computed tomography (CBCT) images. Materials and methodsA total of 349 first mandibular premolars and 416 second premolars from CBCT images with 0.125-mm voxel size and 60 × 60 mm field of view were evaluated. Number of roots, root canals, and C-shaped canals were recorded and statistically analyzed using chi-square test. Root canal configurations were defined according to the Vertucci's classification. Levels and distances of separated multiple canals were reported. ResultsMultiple roots in mandibular first premolars were found at 5.73% while none of second premolars had. Multiple root canals were found in the first premolars at 19.48% and the second premolars at 3.85%. C-shaped canals (C1/C2) were found in the first premolars at 3.72% and the second premolars at 0.48%. All parameters in the first premolars were significantly higher than in the second premolars (p < 0.01). The majority of multiple root canals were defined as Vertucci's type V (1–2 canals). Multiple root canals were frequently separated at the middle level of roots about 6.5–7.0 mm from the cementoenamel junction. ConclusionPrevalence of multiple roots/root canals and C-shaped canals in mandibular first premolars were significantly higher than in mandibular second premolars. Level of separation in multiple root canals was frequently at the mid-root level.

Evaluation of location and dimensions of genial tubercle in patients with class I and II occlusion with cone bean computed tomography images

Introdution: Obstructive sleep apnea syndrome has potentially significant physiological and psychological consequences. The main method to control the obstructive sleep apnea syndrome is surgical advancement of genioglossus muscle (GA) or genial tubercle (GTA). Therefore, for pre-operation arrangements, surgeons definitely need to know the exact location of genial tubercle and the muscles attached to it. The aim of this study was to evaluate the location and dimensions of genial tubercle in the patients with class I and II occlusion with cone bean computed tomography (CBCT).&#x0D; Methods:In this descriptive cross-sectional study, cone bean computed tomographyimages of 152 adults (76 males and 76 females) with class I and II occlusion were inspected and the location and dimensions of genial tubercle (Height =GTH / Width=GTW / the distance between the apices of central teeth and the Superior border of genial tubercle=LI-SGT / the distance between the inferior border of genial tubercle and the inferior border of mandible= IGT-IBM / the anterior diameter of mandible = MT) were evaluated. Patients were classified based on their gender and occlusion type.Independent Kolmogorov-Smirnov tests were used for data analysis and thedata analyzed using SPSS16 software.&#x0D; Results:In all the groups, GTH was located near GTW. The measured data for GTH, GTW, LI-SGT, IGT-IBM and MT were 8.6-06 .57 mm, 8.6-19.47 mm, 7.6-13.56 mm, 8.7-47.40 mm, and 14.11-57.78 mm, respectively. No significant difference was indicated for GTW and LI-SGT based on malocclusion and for LI-SGT based on gender (P&gt;0.05).&#x0D; Conclusion:Various locations and different size of this structure among patients imply that it is necessary for treatment of obstructive sleep apnea to obtain a CBCT image before surgical operation

Assessment of Atlanto-Axial and Mandibular Rotation by Cone Beam Computed Tomography.

The cranial portion of the vertebral segment together with the atlanto-occipital joint represents a very complex area. Since this system could be influenced by different atlas and mandibular position, the aim of this work was to assess atlanto-axial and mandibular rotation. Scanora 3-dimensional cone bean computed tomography images from 205 patients without signs or symptoms of temporomandibular disorder were evaluated. Using a digitalized images analyzer, the axial rotations of atlas and mandible rotation were calculated, measuring the angle with respect to the frontal plane. The same direction for the axial rotation of the mandible and for the atlanto-axial rotation (consistent group) was observed in 80.98% of the patients; opposite directions (inconsistent group) were observed in 19.02%. Among the consistent group, the left rotation was observed in 71.08% of the patients and the right rotation in 28.92%. Absolute values showed a more marked rotation for atlas than mandible and higher values for the left rotation were reported for both.Taking together these data represents important starting points for the knowledge of atlas and mandible relationship and its functional and clinical implication.

In vitro comparison of contemporary radiographic imaging techniques for the measurement of inter-radicular width.

To assess the reliability of inter-radicular measurements taken using dental pantomograms (DPT), long cone periapical radiographs (LCPA) and cone bean computed tomography (CBCT). A typodont simulating a hypodontia patient undergoing fixed appliance treatment was used. LCPAs, DPT, I-CAT and Accuitomo CBCT images were taken and the distances between the edentulous spans were measured at the midpoint of the roots and the cemento-enamel junctions (CEJ) of adjacent teeth. The results of each modality were compared to each other to the actual inter-radicular space. The DPT overestimated inter-radicular widths by 2 mm or more [mean: 2.48; 95% confidence interval (CI): -1.09 to 6.05 mm]. The LCPA overestimated the inter-radicular widths by 1.5 mm with a 95% CI of -0.095 to 4.03 mm. The mean differences between gold standard (model) and Accuitomo was 0.57 mm (95% CI: -0.37 to 1.51 mm) for the root mean and 0.22 mm (95% CI: -0.52 to 0.96 mm) for the CEJ. This was similar to the differences between the model and I-CAT where the inter-radicular root mean difference was 0.38 mm (95% CI: -0.38 to 1.14 mm) and the CEJ mean difference was 0.21 mm (95% CI: -0.50 to 0.92 mm). The CBCT overestimated the root distance by 0.48 mm and the CEJ width by 0.22 mm, which is clinically irrelevant for implant placement. The DPT overestimated inter-radicular width by 2 mm and the LCPA by 1.5 mm and this difference may put roots of adjacent teeth at risk during implant placement.

Clinical and Radiographic Evaluation of Demineralized Freeze-Dried Cancellous Block Allograft for Ridge Augmentation: A Pilot Study.

Bone resorption after tooth extraction is a common problem in implant dentistry. Allografts are one of the therapeutic techniques used to reconstruct the deficient ridge. Although this technique eliminates the need for a surgical donor site, it has yielded contradictory results. The aim of the present pilot study was to evaluate the clinical and radiographic results of the use of demineralized freeze-dried cancellous block allografts (DFDCBAs) in lateral ridge augmentation. Seven patients were included in this study. Lateral reconstruction of bone was performed using DFDCBA with stabilizing screws and resorbable collagen membranes. The ridge width was initially measured during the augmentation surgery. A second measurement was taken 6 months later at the time of implant placement. In addition, cone bean computed tomography images were used at both baseline and at 6-month reentry for measuring the width of bone by applying an acrylic stent with a radiopaque marker at the edentulous area. Paired t test was used to evaluate the statistical differences. The mean increase in the clinical and radiographic ridge widths were 1.70 ± 1.90 and 1.28 ± 1.52 mm, respectively, which were not statistically significant (P = 0.56 and P = 0.067, respectively). The results showed that the use of DFDCBAs in conjunction with resorbable membrane does not yield predictable results in the reconstruction of ridge width deficiencies.