The identification of the mandibular canal (MC) is an important prerequisite for surgical procedures involving the posterior mandible. Cone beam computed tomography (CBCT) represents an advance in imaging technology, but distinguishing the MC from surrounding structures may remain a delicate task.ObjectivesThe aim of this study was to assess the visibility of the MC in different regions on CBCT cross-sectional images.Material and methodsCBCT cross-sectional images of 58 patients (116 hemi-mandibles) were analyzed, and the visibility of the MC in different regions was assessed.ResultsThe MC was clearly visible in 53% of the hemi-mandibles. Difficult and very difficult visualizations were registered in 25% and 22% of the hemi-mandibles, respectively. The visibility of the MC on distal regions was superior when compared to regions closer to the mental foramen. No differences were found between edentulous and tooth-bearing areas.ConclusionsThe MC presents an overall satisfactory visibility on CBCT cross-sectional images in most cases. However, the discrimination of the canal from its surrounds becomes less obvious towards the mental foramen region when cross-sectional images are individually analyzed.

Objective: To evaluate the dimensional changes of dental arches on digital models of open bite treatment with fixed and removable palatal cribs. Materials and Methods: The sample comprised 41 patients of both sexes who were white, aged 7–10 years, and who had mixed dentition, Angle Class I molar relationship, and a negative overbite of at least 1 mm. The sample was randomly divided into two groups: G1, fixed palatal crib; and G2, removable palatal crib. Cast models, obtained initially (T1) and after 1 year of treatment (T2), were scanned by a three-dimensional (3D) scanner, 3Shape R700, producing a 3D image. Measurements were performed by a calibrated examiner using OrthoAnalyzer™ 3D software. Results: At T2–T1, differences were observed between the groups regarding vertical dentoalveolar development and overjet. There was more mandibular incisor extrusion for G1 (−1.66 mm) than for G2 (−0.54 mm). An overjet increase was observed in G1 (0.56 mm), in contrast to a reduction in G2 (−0.40 mm). There was a similar overbite increase for both groups (3.51 mm for fixed palatal crib and 3.88 mm for removable palatal crib). Conclusions: Both the treatment protocols are similarly effective for anterior open bite correction, providing an overbite increase with dentoalveolar arch changes, especially in the anterior region.

Objective The purpose of this study was to determine the accuracy and reliability of two methods of measurements of linear distances (multiplanar 2D and tridimensional reconstruction 3D) obtained from cone-beam computed tomography (CBCT) with different voxel sizes.Material and Methods Ten dry human mandibles were scanned at voxel sizes of 0.2 and 0.4 mm. Craniometric anatomical landmarks were identified twice by two independent operators on the multiplanar reconstructed and on volume rendering images that were generated by the software Dolphin®. Subsequently, physical measurements were performed using a digital caliper. Analysis of variance (ANOVA), intraclass correlation coefficient (ICC) and Bland-Altman were used for evaluating accuracy and reliability (p<0.05).Results Excellent intraobserver reliability and good to high precision interobserver reliability values were found for linear measurements from CBCT 3D and multiplanar images. Measurements performed on multiplanar reconstructed images were more accurate than measurements in volume rendering compared with the gold standard. No statistically significant difference was found between voxel protocols, independently of the measurement method.Conclusions Linear measurements on multiplanar images of 0.2 and 0.4 voxel are reliable and accurate when compared with direct caliper measurements. Caution should be taken in the volume rendering measurements, because the measurements were reliable, but not accurate for all variables. An increased voxel resolution did not result in greater accuracy of mandible measurements and would potentially provide increased patient radiation exposure.

Studies that evaluate the reliability and accuracy of the 3D models are necessary to ensure error predictability and to establish diagnosis, treatment plan, and prognosis in a more realistic way.

Health-related quality of life of patients with squamous cell carcinoma: a comparison according to tumor location Abstract: The aim of this study was to evaluate the health-related quality of life (QOL) of patients with squamous cell carcinoma (SCC) according to tumor location. The sample consisted of 27 patients with primary SCC in the oral cavity (n = 15), pharynx (n = 7), and larynx (n = 5) who were undergoing cancer treatment at the Cancer Hospital of Londrina, regardless of age, sex, clinical stage, and type of antineoplastic treatment. Health-related QOL was evaluated using the 30-item CancerQuality of Life Questionnaire (QLQ-C30), the 35-item Head and Neck Cancer-Quality of Life Questionnaire (QLQ-HN35), and the University of Washington Quality of Life Questionnaire (UW-QOL). These questionnaires were administered individually to each patient before ambulatory care. Sociodemographic data (age and sex) and clinical data (T stage, tumor location, and type of antineoplastic treatment) were collected from the patients' medical records. Scores were compared according to tumor location using the chi-squared test and one-way analysis of variance (p < 0.05). No score differed significantly according to tumor location. It can be concluded that the health-related QOL of patients with SCC was not influenced by tumor location.