1,720,966 research outputs found
Influence of Platform-Switched Restoration on Bone Resorption in Patients Treated with Wide-Diameter, External-Hex–Connection Dental Implants: A 10-Year Follow-up Study
No full textPurpose: To investigate and assess the differences in crestal bone loss (CBL) between wide-diameter, external-hexagon– connection implants restored with platform-switching (PS) and platform-matching (PM) restorations with a follow-up of 10 years. Materials and Methods: This study retrospectively analyzed the updated and enlarged dataset of a 5-year prospective clinical study at 10-year follow-up. The data concerns 182 healthy adult subjects treated in a private dental practice who received a single wide-diameter implant with an external hexagon connection in the molar area, restored with either a PS restoration (test) or PM restoration (control). The amount of CBL was radiographically measured at each annual follow-up, as well as after 5 and 10 years of implant loading. In evaluating the association between the two types of abutments and bone loss (including change over time), a linear mixed effects model was run for longitudinal data. Results: Implants connected with PS restorations exhibited significantly lower reduction (0.25 mm) in CBL than those joined to PM restorations (P <.001; 95% CI from 0.22 to 0.29). However, both groups presented a higher increase in bone loss during the first year (0.58 mm in PS and 0.83 mm in PM) and a linear increment thereafter until the 10-year followup (0.046 mm/year; P <.001; 95% CI from.042 to.049). Conclusion: Notwithstanding the limitations of this study, it can be concluded that after 10 years of follow-up, the implant with a wide diameter and external-hexagon connection restored with a PS abutment seems to be more effective in reducing bone loss compared with the PM abutment. Int J Oral Maxillofac Implants 2023;38:46–52. doi: 10.11607/jomi.974
Arch width changes with a rapid maxillary expansion appliance anchored to the primary teeth
No full textObjective: To examine the dimensional changes after rapid maxillary expansion (RME) carried out in the transitional dentition with the primary teeth as anchorage. Materials and Methods: Group A was composed of 31 consecutive transitional dentition patients with posterior quadrant crossbites treated with a Haas-type RME appliance anchored on the maxillary primary molars and canines. No treatment was administered after palatal expansion. Study models were made before RME (T1), at appliance removal (T2), and at least 1 year after appliance removal (T3). A control sample of 60 individuals with posterior quadrant crossbites who had had no orthodontic treatment was categorized into group B (30 individuals with an average age comparable with the treated patients at T2) and group C (30 individuals with an average age comparable with the treated patients at T3). Results: Permanent molar crossbites were corrected at T2, and this correction was maintained at T3 in all patients. The mean permanent maxillary intermolar width was 42.6 ± 2.3 mm at T1, 46.7 ± 1.9 mm at T2 (P < .01), and 46.3 ± 1.8 mm at T3 (P < .01) in group A; 42.9 ± 2.7 mm (P < .01) in group B; and 44.4 ± 3.0 (P < .01) in group C. Premolar and canine widths were slightly wider than the control at T3. Conclusion: To avoid undesirable treatment-induced effects on maxillary permanent molars, a stable transverse correction could be achieved with the RME appliance anchored on the primary teeth. © 2007 by The EH Angle Education and Research Foundation, Inc
Mandibular molar uprighting using mini-implants: Different approaches for different clinical cases-Two case reports.
No full textDental arch changes following rapid maxillary expansion.
No full textThe purpose of this research was to evaluate changes in upper arch dimension and form following rapid maxillary expansion (RME) using a modified Haas appliance in the primary dentition. The sample comprised 49 children [17 males, 32 females, mean age 7 years 5 months, standard deviation (SD) 1 year 1 month] with a crossbite or maxillary crowding. Twenty patients had a normal SN-GoGn angle (7 males, 13 females, mean 33.25 degrees, SD 2.10), three were low angle (1 male, 2 females, mean 27.67 degrees, SD 2.31), and 22 were high angle (8 males, 14 females, mean 39.95 degrees, SD 3.15). The vertical dimensions of four patients could not be measured, due to the unavailability of radiographs. Expansion was undertaken to either correct a crossbite or treat maxillary crowding. The upper dental casts were analysed using a computerized system: before treatment (T1), at appliance removal (T2), and 2 years 4 months after appliance removal (T3). Using bootstrap statistical analysis applied to distance ratio values [Euclidean distance matrix analysis (EDMA)], it was found that 48 patients showed a change in arch form. In 40.82 per cent (n = 20, group A), the arch form changed from T1 to T2, T1 to T3, and T2 to T3. In 32.65 per cent (n = 16, group B), it varied from T1 to T2 but relapsed at T3 to the form of T1. For 24.5 per cent (n = 12, group C), it changed from T1 to T2 but maintained the same form at T3. The favourable characteristics for obtaining expansion, identified by logistic regression analysis, were being male, of an immature stage of dental development (lateral incisor not fully erupted) and the presence of a lateral crossbite. Intercanine and intermolar widths, arch length, and the distance between the interincisive point and the line joining the canines (depth of the intercanine arch) at the different time points were analysed using a two-tailed t-test (P < 0.05). For the whole group, the increase in intercanine and intermolar width and in the depth of the intercanine arch was significant. Comparison between groups A, B, and C was undertaken using an analysis of variance, but there was no significant difference between the groups. This modified type of Haas appliance was able to increase the transverse dimension of the maxillary dental arch in the mixed dentition. The most appropriate timing for treatment appears to be before the eruption of the permanent lateral incisors
Cemented versus screw-retained implant-supported single-tooth crowns: a 10-year randomised controlled trial.
No full textDental arch analysis system
No full textThe purpose of our research is to describe a computerized method, which enables orthodontists and researchers to analyze variation of dental arch form and dimension. The analysis system is composed of two independent parts: the database, where the images of scanned dental casts are stored, and the software. The operator uses the software to identify some landmarks on dental cast images. Corresponding distances are calculated (interincisive, intercanine and intermolar widths and the curve axis). Then the software algorithms calculate and draw the curves passing trough the selected landmarks (conics, catenary, cubic spline and polynomial curves). In the chosen curves the arch length is measured. The dental cast data, recorded at different times of the subject's life or in different steps of orthodontic treatment, are compared in order to evaluate the change in dimension (arch length and width) and form (shape). The statistical analysis of the data evaluates the variation in form and in d..
COVID-19 outbreak perception in Italian dentists
Full text linkThe aim of this study is an evaluation of the Italian dentists’ knowledge regarding COVID-19 and their perception of the risks associated with COVID-19, their attitude in resuming their activities, and how they judge the institutional intervention on a health and economic basis. Methods: This research evaluated Italian dentists from 11 to 18 April 2020, using a questionnaire submitted via Google Forms (Alphabet, Mountain View, CA, USA). It consisted of different investigations about sociodemographic aspects, profession-related characteristics, knowledge about COVID-19 infection transmission modalities, symptoms, and attitude in treating potentially infected patients. Statistical analysis was performed using the Pearson chi2 test and Student t-test. The α-level was fixed at p = 0.05. All data were analyzed with STATA 16 (StataCorp LP, College Station, TX, USA). Results: 1500 dentists (664 men and 836 women) completed the questionnaire. The majority of respondents declared having been trained in infection prevention procedures (64.3%) but not specifically to prevent the spread of COVID-19 (48.7%). A total of 57.2% declared that they were not trained sufficiently to restart working after lockdown, with a significantly higher prevalence (Pearson chi2 test, p < 0.001) among women (62.3%) than men (50.9%). Conclusion: Italian dentists were informed correctly on the mode of transmission but partially missed COVID-19 symptoms. Dentists considered the virus infection highly dangerous, and they were not confident in being able to work safely. The lack of precise operating guidelines creates uncertainties on infection control measures and appropriate personal protective equipment (PPE) use. The participants revealed apprehension for their health and the current and future economic situation of their practices
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
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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