1,720,960 research outputs found
Chairside CAD/CAM Materials: Current Trends of Clinical Uses
Get PDFRestorative materials are experiencing an extensive upgrade thanks to the use of chair- side Computer-aided design/computer-assisted manufacturing (CAD/CAM) restorations. There- fore, due to the variety offered in the market, choosing the best material could be puzzling for the practitioner. The clinical outcome of the restoration is influenced mainly by the material and its handling than by the fabrication process (i.e., CAD/CAM). Information on the restorative materials performances can be difficult to gather and compare. The aim of this article is to provide an over- view of chairside CAD/CAM materials, their classification, and clinically relevant aspects that en- able the reader to select the most appropriate material for predictable success
Comparison of Non-Surgical Methods for Implant Surface Treatment in Simulated Bone Resorption Patterns: An In Vitro Study
No full textBackground: Peri-implantitis is the leading cause of implant failure, with a reported prevalence of 22–45%. Effective removal of bacterial biofilm from the implant surface is critical to non-surgical therapy. This study aimed to assess the efficacy of different implant surface cleaning methods across various bone defect configurations, considering operator experience. Methods: Thirty-six dental implants were coated to simulate biofilm, mounted in resin blocks with bone defects of varying geometries, and covered with silicone to simulate soft tissue. Three operators with differing levels of experience treated the implant surfaces using four instruments: a titanium curette (TiCu), ultrasonic scaler (US), titanium brush (TiBr), and air abrasion with erythritol (AirPo). Each combination was tested in triplicate. Implants were photographed and analyzed with dedicated software to quantify cleaning efficacy. Results: The expert dentist achieved the highest average cleaning efficacy (36.6%). The most effective tools were the titanium brush (37.2%) and ultrasonic scaler (35.0%), followed by the titanium curette (28.1%) and air-abrasion (22.9%). The first two instruments were the least operator-dependent. Among the defect types, the 60° defect was the easiest to clean. Complete implant surface decontamination was not achieved in any scenario. Conclusions: Ultrasonic scalers and titanium brushes demonstrated the highest and most consistent cleaning efficacy, independent of operator skill level. Sixty-degree defects were the most amenable to cleaning. These findings underscore the need to tailor decontamination approaches based on defect geometry and to consider combining non-surgical methods with adjunctive or surgical interventions, which may ultimately enhance clinical decision-making and improve treatment outcomes
Electrospun Collagen-Coated Nanofiber Membranes Functionalized with Silver Nanoparticles for Advanced Wound Healing Applications
Get PDFComplex wounds pose a significant healthcare challenge due to their susceptibility to infections and delayed healing. This study focuses on developing electrospun polycaprolactone (PCL) nanofiber membranes coated with Type I collagen derived from bovine skin and functionalized with silver nanoparticles (AgNPs) to address these issues. The collagen coating enhances biocompatibility, while AgNPs synthesized through chemical reduction with sodium citrate provide broad-spectrum antimicrobial properties. The physical properties of the membranes were characterized using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Results showed the formation of nanofibers without defects and the uniform distribution of AgNPs. A swelling test and contact angle measurements confirmed that the membranes provided an optimal environment for wound healing. In vitro biological assays with murine 3T3 fibroblasts revealed statistically significant (p ≤ 0.05) differences in cell viability among the membranes at 24 h (p = 0.0002) and 72 h (p = 0.022), demonstrating the biocompatibility of collagen-coated membranes and the minimal cytotoxicity of AgNPs. Antibacterial efficacy was evaluated against Staphylococcus aureus (SA), Pseudomonas aeruginosa (PA), and Vancomycin-resistant Enterococcus (VRE), with the significant inhibition of biofilm formation observed for VRE (p = 0.006). Overall, this novel combination of collagen-coated electrospun PCL nanofibers with AgNPs offers a promising strategy for advanced wound dressings, providing antimicrobial benefits. Future in vivo studies are warranted to further validate its clinical and regenerative potential
Efficacy of two dosages of dexamethasone administered by submucosal injection on postoperative sequelae after third molar surgery: A retrospective study
No full textABSTRACT: Purpose: A retrospective clinical study was performed to compare the post-operative sequelae of the submucosal administration of two different low dosages of dexamethasone, after the surgical extraction of lower third molars. Methods: Data regarding edema, trismus, pain and analgesic consumption were collected from 150 subjects, selecting three equal groups (n= 50): a control group with no administered dexamethasone (G1); submucosal injection of dexamethasone 2 mg/0.5 ml (G2) and submucosal injection of dexamethasone 4 mg/1 ml (G3). Collected data were evaluated at three different time points: T0 before surgery, T1 on the third day after surgery and T2 on the 7th day after surgery. Patients’ gender and age were also considered for statistical purposes. Results: The effects on facial swelling reduction were statistically significant in G2 at T1 in the male subgroup. With trismus, the differences between the time points considered were statistically significant in G2 in the subgroup of subjects younger than 25 years old. Differences in analgesics taken were statistically significant when G1 and G2 were compared at T1. (Am J Dent 2022;35:233-237)
Evaluating the stability of extended-pour alginate impression materials by using an optical scanning and digital method
Get PDFStatement of problem: The dimensional stability of alginate dental impressions is a key factor for the reliability of delayed gypsum pouring and digital scanning. However, studies of the dimensional stability of alginates with conventional methods that consider the dimensional variations of large impressions are lacking.
Purpose: The purpose of this in vitro study was to investigate and compare 2 digital methods for the analysis of dimensional stability of large impressions made with 5 different extended-pour alginates and to assess dimensional stability up to 5 days.
Material and methods: Impressions of a simplified master maxillary model were made with Alginoplast, Blueprint, Hydrogum 5, Orthoprint, and Phase Plus and then analyzed at different time points. Digital scans of the alginate impression surfaces were obtained with a desktop scanner and analyzed by evaluating the linear measurements between reference points and by using a novel method that consists of the analysis of the entire scanned surface to evaluate the expansion and contraction of the impressions.
Results: The first method revealed that the dimensional changes did not exceed 0.5%, with the exception of Phase Plus at day 3 (-0.6 ±0.7%), and the average dimensional variation was always lower than or equal to 0.2 mm. Blueprint was the most stable material (-0.2 ±0.6%). The second method revealed dimensional variations always lower than 0.03 mm and confirmed Blueprint as the best performing material (0.001 ±0.006 mm) and Phase Plus the worst (-0.019 ±0.006 mm).
Conclusions: Both the methods used to evaluate alginate stability showed that the analyzed materials remain stable over time; the dimensional variations showed a similar trend, with differences in the absolute values depending on the applied method. Linear measurements are affected by the operator and choice of reference points; however, by evaluating the average variations of the entire structure surfaces, local variations should be minimized. The evaluation of the average variations with the second method offers the advantage of a rapid visual representation of these variations
Efficacy of Alveolar Ridge Preservation after Maxillary Molar Extraction in Reducing Crestal Bone Resorption and Sinus Pneumatization: A Multicenter Prospective Case-Control Study
Get PDFAim. To evaluate, with three-dimensional analysis, the effectiveness of alveolar ridge preservation (ARP) after maxillary molar extraction in reducing alveolar bone resorption and maxillary sinus pneumatization when compared to unassisted socket healing. Methods. Patients were included in the study following inclusion criteria and underwent minimally traumatic maxillary molar extraction followed by ARP using synthetic nanohydroxyapatite (Fisiograft Bone, Ghimas, Italy) (test group) or unassisted socket healing (control group). Cone-beam computerized tomographies (CBCT) were performed immediately after tooth extraction (T0) and 6 months postoperatively (T1). CBCTs were superimposed by using a specific software (Amira, Thermo Fisher Scientific, USA) and the following items were analyzed in both groups: (i) postextractive maxillary sinus floor expansion in coronal direction and (ii) postextractive alveolar bone dimensional changes (both vertical and horizontal). All data were tested for normality and equality of variance and subsequently analyzed by independent samples T-test and Mann–Whitney test. Results. Thirty patients were treated by three centers and twenty-six (test n=13; control n=13) were included in the final analysis. Mean sinus pneumatization at T1 was 0.69±0.48 mm in the test group and 1.04±0.67 mm in the control group (p=0.15). Mean vertical reduction of the alveolar bone at T1 was 1.62±0.49 mm in the test group and 2.01±0.84 mm in the control group (p=0.08). Mean horizontal resorption of crestal bone at T1 was 2.73±1.68 mm in test group and 3.63±2.24 mm in control group (p=0.24). Conclusions. It could be suggested that ARP performed after maxillary molar extraction may reduce the entity of sinus pneumatization and alveolar bone resorption, compared to unassisted socket healing. This technique could decrease the necessity of advanced regenerative procedures prior to dental implant placement in posterior maxilla
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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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