Percorrer por autor "Costa, Hélder Nunes"
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- Bone availability in the sagittal dimension of the infrazygomatic crest for miniscrew insertion : a retrospective cone-beam computed tomography studyPublication . Furão, Susana; Bugaighis, Iman; Proença, Luís; Brito, José; Costa, Hélder Nunes; Pereira, François Durand; Pereira, Pedro MarianoBackground: There is limited information available regarding the bone volume in the sagittal dimension of the infrazygomatic crest (IZC) that is safe for the insertion of a temporary skeletal anchorage device. The objective of this study was to assess the sagittal bone availability when the anterior and posterior walls of the IZC reach an inclination of 45°. Methods: A cross-sectional investigation was undertaken on 100 cone-beam computed tomography scans of 40 males and 60 females. A total of 20 landmarks were digitized for each IZC outline, 1 mm from the vestibular alveolar bone, and their x, y, and z coordinates were extracted. Afterward, the sagittal measurement of the IZC at which the curvature reached 45° was recorded. Symmetry of measurements was assessed using paired-samples t tests. In addition, these measurements were compared as a function of sex and age group (≤21 vs >21 years) using an independent-samples t test and the Spearman rank correlation coefficient test (P <0.05). Results: There were no significant differences between paired sagittal measurements of the IZC (3.5 ± 1.5 mm on the right side and 3.6 ± 1.3 mm on the left side; P = 0.144), except for younger patients (P = 0.030). In addition, no significant differences were found between corresponding male and female measurements (P ≥0.149). A significant discrepancy was identified between the younger age group (3.2 ± 1.2 mm) and the older cohort (3.8 ± 1.6 mm) for the sagittal dimension of the right IZC (P = 0.038), with an estimated mean difference of 0.03-1.16 mm (95% confidence interval). A significant positive weak correlation was found between the sagittal dimension of the right IZC and age (ρ = 0.201; P = 0.045). Conclusions: Sufficient IZC bone volume is available at an angle of 45° for inserting a temporary skeletal anchorage device, with no sex or side variation, except for the significantly greater sagittal dimension of the right IZC in older patients.
- Class III treatment strategiesPublication . Costa, Hélder Nunes
- A computerized tomography study of the morphological interrelationship between the temporal bones and the craniofacial complexPublication . Costa, Hélder Nunes; Slavicek, Rudolf; Sato, Sadao"The hypothesis that the temporal bones are at the center of the dynamics of the craniofacial complex, directly influencing facial morphology, has been put forward long ago. This study examines the role of the spatial positioning of temporal bones (frontal and sagittal inclination) in terms of influencing overall facial morphology. Several 3D linear, angular and orthogonal measurements obtained through computerized analysis of virtual models of 163 modern human skulls reconstructed from Cone-beam Computed Tomography (CBCT) images were analyzed and correlated. Additionally, the sample was divided into two subgroups based on the median value of temporal bone sagittal inclination [anterior rotation group (n=82); posterior rotation group (n=81)], and differences between groups evaluated. Correlation coefficients showed that sagittal inclination of the temporal bone was significantly (p <0.01) related to midline flexion, transversal width, and anterior-posterior length of the basicranium, to the anterior-posterior positioning of the mandible and maxilla, and posterior midfacial height. Frontal inclination of the temporal bone was significantly related (p <0.01) to basicranium anterior-posterior and transversal dimensions, and to posterior midfacial height. In comparison with the posterior rotation group, the anterior rotation group presented a less flexed and anterior-posteriorly longer cranial base, a narrower skull, porion and the articular eminence located more superiorly and posteriorly, a shorter posterior midfacial height, the palatal plane rotated clockwise, a more retrognathic maxilla and mandible, and the upper posterior occlusal plane more inclined and posteriorly located. The results suggest that differences in craniofacial morphological are highly integrated with differences in the positional relationship of the temporal bones. The sagittal inclination of the temporal bone seems to have a greater impact on the 3D morphology of the craniofacial complex than frontal inclination."
- Perception of need for further refinement in a clear aligner treatment among orthodontists, dentists and laypeople : a retrospective studyPublication . Oliveira, Patrícia; Bugaighis, Iman; Costa, Hélder Nunes; Pereira, Pedro MarianoClear aligner treatment often requires further refinement to improve the orthodontic treatment outcome. However, the perceptions of treatment outcomes evaluated by orthodontists and dentists are sparse, and laypeople’s perceptions have yet to be explored. Here, we explore the perceptions of orthodontists, dentists, and laypeople concerning the treatment outcomes achieved after completing the first sequence of aligners. This cross-sectional study involved 37 orthodontists, 67 dentists, and 93 laypeople. We administered an online questionnaire containing intra-oral photographs of nine completed cases with pre- and post-first sequences of aligners. As a control, we used a digital prediction system for the treatment outcome. Self-perception was reported using a visual analog scale. Both orthodontists and dentists had similar perceptions about treatment outcomes (p = 0.363) but significantly differed from laypeople (p ≤ 0.0001). Both orthodontists and dentists recommended further treatment; orthodontists were more critical than dentists (p ≤ 0.001). Orthodontists were more critical than dentists in their evaluations of the need for further treatments; however, their perceptions of treatment outcomes were similar. Laypeople were more satisfied with the treatment outcomes, were less concerned with occlusion, and were more focused on the aesthetic results of the treatment.