1,720,990 research outputs found
Perceptions of dental professionals and laypeople to altered dental esthetics in cases with congenitally missing maxillary lateral incisors
Full text linkThe smile perception of patients is not strictly related to standardized protocols and technical implications which certainly affect clinicians' decisions. The absence of maxillary lateral incisors could affect smile esthetics either with treatment or not. The aim of the present study was to investigate if different perceptions on altered smiles due to missing maxillary lateral incisors, with or without treatment, exist among different groups of people (laypersons, adult orthodontic patients, general dentists, and orthodontists).An ideal smile model was selected and altered simulating different malocclusions and treatment options. Twelve simulations were submitted to four categories of respondents: laypeople, adult orthodontic patients, general dentists and orthodontists. They were asked to express smile perception for each simulation by ranking and rating simulations using a 0 to 100 visual analog scale. Analysis of variance was used to determine if there were statistically significant differences in values assigned among the four categories of respondents for each simulation.Significant differences in smile perceptions were found between professionals (dentists and orthodontists) and laypeople. Presence of dental tipping and marked diastema in the arch were disharmonious aspects less tolerated in a smile by all categories of evaluators. Simulations associated with space closure orthodontic treatment were ranked as the most attractive smile and significantly ranked higher by dental professionals than patients and laypeople.Treatment, absence of diastema, and symmetry were the most accepted characteristics by all categories of respondents. Ideal orthodontic treatment options might be overestimated by clinicians when compared to laypeople's smile perception
Upper canine response to rapid maxillary expander anchored to deciduous vs. permanent molars
No full textPurpose: To understand whether two different designs of Haas-type rapid maxillary expander (H‐RME) might have a different influence on canine eruption. Patients and methods: In all, 108 subjects seeking orthodontic treatment were selected and divided into two groups—H‐RME with bands on the upper second deciduous molars (GrE), H‐RME with bands on the upper first permanent molars (Gr6)—and were also compared to an historical untreated control group (CG) of 29 subjects. Panoramic x‐rays (OPG) were performed before and after RME (T0–T1: 16 ± 7 months) and the upper canine angulation to the midline (“α” angle) was measured on both pre- and posttreatment OPG. Results: A significant improvement of the canine position (decrease of the α angle) following RME in subjects with mixed dentition was reported in both treated groups, although the different design of the RME did not significantly affect canine angulation. Canine angulation in untreated subjects with transversal discrepancy did not improve significantly. Conclusion: Using RME in the early mixed dentition appears to be an effective procedure to increase the rate of eruption of maxillary canines, but the position of the bands on the upper second deciduous molars or on the upper first permanent molars and the significant different expansion of the upper dental arch at the canine level does not significantly influence the canine angulation following early treatment therapy
3D facial soft tissue changes after rapid maxillary expansion on primary teeth: A randomized clinical trial
No full textObjectives: The aim of the present randomized controlled trial (RCT) was therefore the tridimensional evaluation of soft tissue changes after rapid maxillary expansion in growing patients. Setting and Sample Population: Treated group comprised 17 patients (10 males and 7 females) with a mean age of 9.8 ± 1.2 years, and control group comprised 17 patients (13 males and 4 females) with a mean age of 9.1 ± 2.1 years. Material & Methods: All patients of the treated group underwent maxillary expansion with Haas-type expander while patients of the control group underwent no treatment. 3D facial scans were acquired at T1, at the beginning of treatment or observation period, and at T2, 18 months apart. The mean interval between the timepoints was 18.2 ± 0.4 months. Results: The main differences between groups were reported in the nasal area. Nasal width (Alr-All) significantly increased in the treated group compared with the control. The increase in intereye and mouth width in the study group did not show differences with the control group. No significant differences were reported for lips’ protrusion, angular measurements and facial heights between groups. The total nose volume difference was significantly higher in the treated group compared with control, and this result was related mainly to the significant increase in the nasal dorsum volume. Conclusion: Maxillary expansion produced significant increase in the nasal base and nasal volumes, but its clinical relevance is still questionable
Role of mandibular displacement and airway size in improving breathing after rapid maxillary expansion.
Full text linkOral breathing and maxillary deficiency are often associated with steep mandibular plane angle, and retrognathic mandible compared with the faces of healthy controls. Some studies suggested that after rapid maxillary expansion, improvement in nasal breathing and repositioning of mandible with transitory increasing of facial height and, in some cases, spontaneous forward repositioning might occur. The abovementioned mandibular effects could contribute to enlarge oropharynx volume with repositioning of tongue and soft palate with an improvement of upper airway volume after treatment. The aim of this study was to investigate by cone beam computed tomography the role of oropharyngeal volume and mandibular position changes after rapid maxillary expansion in patients showing improved breathing pattern confirmed by polysomnography exam.The final sample of this retrospective study comprised 14 Caucasian patients (mean age 7.6 years) who undergone rapid maxillary expansion with Haas-type expander banded on second deciduous upper molars. Cone beam computed tomography scans and polysomnography exams were collected before placing the appliance (T0) and after 12 months (T1). Mandibular landmarks localization and airway semiautomatic segmentation on cone beam computed tomography scans allowed airway volume computing and measurements.No significant differences were found between oropharyngeal airway changes and mandibular displacement after rapid maxillary expansion in growing patients.The suggested improvement in upper airway and breathing after rapid maxillary expansion should be further related to different compartments of airway such as rhinopharynx and nasal cavity
Influence of facial components in class III malocclusion esthetic perception of orthodontists, patients, and laypersons
No full textPurpose: The aim of the present study was to investigate the influence of different facial components (face length, lip volume, nose size, and cheekbone contour) on the perception of facial attractiveness of patients with Angle class III malocclusion in different categories of responders (orthodontists, laypersons, patients) with two-dimensional (2D) and three-dimensional (3D) simulations. Methods: An ideal standard 3D face was manipulated to create a class III facial malocclusion. Four facial components were modified (face length, lip volume, nose size and cheekbone contour) and the resulting simulations were used to obtain 2D figures and 3D videos, which were evaluated in a survey by orthodontists, patients, and laypersons. Results: No significant differences were detected between the 2D figures and 3D video simulations. Good correspondence was shown between the three categories of responders for the most and the least attractive faces. Smaller lips and bigger nose, regardless to the vertical dimension (short or long face), were found to be the least attractive features with agreement of all respondents. Conclusion: Regarding class III facial attractiveness perception, the sum of all facial features and not the alteration of a single component alone seems to play a key role in the perception of facial attractiveness. The 2D or 3D perspective did not play a significant role in perception and the analyzed categories of responders did not show significant differences when perceiving facial attractiveness of the utilized simulations
Comparison of cephalometric changes in Class II growing patients with increased vertical dimension after high-pull and cervical headgear treatment
No full textAim The aim of the present study was to evaluate the cephalometric changes in growing Class II patients with increased vertical dimension treated with cervical or high-pull headgear, by using an untreated control group with similar skeletal characteristics. Materials and methods From the initial sample, 56 patients satisfied the inclusion and exclusion criteria; 20 patients were treated with cervical headgear (CHG), 15 with high-pull headgear (HHG), and 21 were not treated (CG). Cephalograms were available for each subject at baseline (T1) and after treatment/observation time (T2) for the three groups. A total of 17 measurements were taken on the lateral head films. Group comparison among CHG, HHG and CG was done using ANOVA test. Results In the CHG group, 10 measurements presented significant T1-T2 modifications, while in the HHG only 5. The greatest reduction of Ba-N-A is observed in CHG when compared to HHG. The average reduction of convexity and overjet is greatest in CHG, followed by HHG and then CG. The greatest mean difference of U6 to L6 distance is observed in CHG. Conclusions In Class II high-angle growing patients, cervical headgear seems to be preferred in the correction of maxillary protrusion, molar relationship and increased anterior facial height. Extrusion of the upper molar may favour forward repositioning of the mandible and clockwise rotation in Class II patients with increased vertical dimension
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Effects of orthopedic maxillary expansion on nasal cavity size in growing subjects: a low dose computer tomography clinical trial
No full textOBJECTIVE: The aim of this retrospective clinical trial was to evaluate the effects of rapid maxillary expansion on skeletal nasal cavity size in growing subjects by use of low dose computer tomography.
METHODS:
Eight Caucasian children (three male; five female) with a mean age of 9.7 years (SD±1.41) were the final sample of this research that underwent palatal expansion as a first phase of orthodontic treatment. The maxillary expander was banded to the upper first molars and was activated according a rapid maxillary expansion protocol. Low-dose computer tomography examinations of maxilla and of the low portion of nasal cavity were performed before inserting the maxillary expander (T0) and at the end of retention (T1), 7 months later. A low-dose computer tomography protocol was applied during the exams. Image processing was achieved in 3 steps: reslicing; dental and skeletal measurements; skeletal nasal volume computing. A set of reproducible skeletal and dental landmarks were located in the coronal passing through the first upper right molar furcation. Using the landmarks, a set of transverse linear measurements were identified to estimate maximum nasal width and nasal floor width. To compute the nasal volume the lower portion of the nasal cavity was set as region of interest. Nasal volume was calculated using a set of coronal slices. In each coronal slice, the cortical bone of the nasal cavity was identified and selected with a segmentation technique. Dependent t-tests were used to evaluate changes due to expansion. For all tests, a significance level of P<0.05 was used.
RESULTS:
Rapid maxillary expansion produced significant increases of linear transverse skeletal measurements, these increments were bigger in the lower portion of the nasal cavities: nasal floor width (+3.15 mm; SD ± 0.99), maximum nasal width (+2.47 mm; SD ± 0.99). Rapid maxillary expansion produced significant increment of the total nasal volume (+1.27 cm(3) ± SD 0.65). The anterior volume increase was 0.58 cm(3) while the posterior one was 0.69 cm(3).
CONCLUSION:
In growing subjects RME is able to significantly enlarge the dimension of nasal cavity. The increment is bigger in the lower part of the nose and equally distributed between the anterior e the posterior part of the nasal cavity
PEEK Retainers without CAD-CAM: Simple Solutions for Everyday Challenges
Full text linkBackground: The need to perform occasional or continuous MRI exams and the interference with metal orthodontic appliances might be important and take a primary role during retention since the retention period is significantly longer than orthodontic treatment. Several non-metallic materials were proposed as potential alternatives to perform fixed retainers in orthodontics, but they showed internal limits. Methods: Polyetheretherketone (PEEK) was used in the present clinical report as a fixed orthodontic retainer in the lower arch in order to perform an appliance with mechanical properties comparable to metallic ones but with a higher biocompatibility material and without the need for removal in case of an MRI exam. The retainer wire was handmade in the studio and then shaped to fit the arch. Results: PEEK showed a good capability for constructing a lingual fixed retainer compared to other aesthetic non-metallic and metallic materials. Conclusions: To the best of our knowledge, this study proposes how to easily build a retainer in PEEK and provides a clinical example of how this material can be beneficial
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