Evaluation of Marginal Fit of CAD/CAM Ceramic Crowns and Scanning Time Using Different Intraoral Scanning Systems.

This study aimed to evaluate the scanning time and marginal fit of CAD/CAM crowns fabricated using different intraoral scanning systems (IOS) (O1-Omnicam 1.0, O2-Omnicam 2.0, PS-Primescan).

Surface characteristics of resin composite cores and bond strength to CAD/CAM resin matrix glass-ceramic restorations after different treatment protocols.

The purpose of this study was to evaluate the impact of various mechanical surface treatments on the surface roughness and microtensile bond strength (µTBS) of aged composite resin cores bonded to CAD/CAM restorations. Composite resin specimens (Filtek Z350 XT, 3M-ESPE/Solventum) were thermally aged and subsequently divided into four groups (n = 36) according to surface treatments: UI-cleaning with ultrasonic diamond tip; AO-sandblasting with 50 µm AlO; DB-cleaning with diamond burs; and CG-positive control group, without aging or surface treatment. Surface roughness was assessed using a profilometer and interferometer, with measurements taken on both sides of each specimen (n = 12).

Influence of fabrication method on the marginal fit of temporary restorations.

Computer-aided manufacturing (CAM) technology allows the use of different manufacturing techniques. This in vitro study aimed to evaluate the marginal fit of temporary restorations manufactured using conventional chairside methods, milling, and three-dimensional printing. Fifteen 3-element temporary restorations specimens were produced and categorized into three groups: non-digital, obtained using the conventional chairside method (GC); milled (GM); and three-dimensionally printed (GP).

Accuracy of Conventional and 3D-Printed Casts for Partial Fixed Prostheses.

Purpose: To evaluate and compare the accuracy of conventional and 3D-printed casts using five different 3D printers.

Materials And Methods: In the control group (CG group, n = 5), five conventional impressions using light- and heavy-body polyvinyl siloxane were obtained from the master model, resulting in five stone models. In the test groups, five different scans were performed by a well-trained and experienced clinician using a TRIOS intraoral scanner.

Physical and mechanical properties of four 3D-printed resins at two different thick layers: An in vitro comparative study.

Objectives: This in vitro comparative study aimed to evaluate the physical and mechanical properties of four 3D-printed resins with two different thickness layers.

Methods: Four printed resins (VarseoSmile Crown Plus, VSC; NexDent C&B MFH, MFH; Nanolab 3D, NNL; and Resilab 3D Temp, RSL) were printed with 50 µm and 100 µm layer thickness, resulting in 80 bars measuring 25 × 2×2 mm. The specimens underwent a Raman spectroscopy for degree of conversion, confocal laser scanning microscopy for surface roughness (Sa), three-point bending test for flexural strength and elastic modulus, and a Vickers hardness test (VHN).

Influence of the geometry of the screwdriver-screw connection on the reverse torque of UCLA screws.

The aim of this study was to evaluate the influence of the geometry of the screwdriver-screw connection on the reverse torque of UCLA screws after repeated cycles of tightening and loosening in an implant-supported prosthesis. Thirty sets of external hex titanium implants, UCLA abutments, and UCLA abutment screws were divided into 3 experimental groups (n = 10). In the square group, the implant and UCLA abutment system were mounted in an upright position using a screw with a square screwdriver-screw connection.

Effect of exposure time and moving the curing light on the degree of conversion and Knoop microhardness of light-cured resin cements.

Objective: To evaluate the effect of exposure time and moving the light-curing unit (LCU) on the degree of conversion (DC) and Knoop microhardness (KH) of two resin cements that were light-cured through ceramic.

Methods: Two resin cements: AllCem Veneer APS (FGM) and Variolink Esthetic LC (Ivoclar Vivadent) were placed into a 0.3 mm thick matrix in 6 locations representing the canine to canine.

Influence of operator experience, scanner type, and scan size on 3D scans.

Statement Of Problem: Intraoral scanners (IOSs) have some inherent distortions caused by optical and/or software imperfections. However, how other factors such as operator experience, scan time, scanner type, and scan size influence scan accuracy is not clear.

Purpose: The purpose of this in vitro study was to evaluate the trueness and precision of scans performed by 3 professionals with different levels of experience by using 2 IOSs.

Microstructural and mechanical analysis of two CAD-CAM lithium disilicate glass-reinforced ceramics.

The aim of this study was to analyze the structural, morphological and mechanical properties of two different lithium disilicate glass-reinforced ceramics for CAD-CAM systems (IPS e.max CAD and Rosetta SM). Five methodologies were used for both ceramics: microstructure (n = 2) was analyzed using x-ray diffraction (XRD); morphological properties (n = 2) were analyzed by scanning electron microscopy (SEM), with and without hydrofluoric etching; porosity (n = 3) was assessed using 3D micro-computed tomography (micro-CT); flexural strength was measured (n =1 0) using the three-point bending test; and bond strength was determined with self-adhesive resin cement (n = 10), using a microshear bond test.

Biomechanical behavior of extra-narrow implants after fatigue and pull-out tests.

Statement Of Problem: Narrow implants have limited indications, and implant fracture may occur when these indications are not followed.

Purpose: The purpose of this in vitro study was to investigate the mechanical behavior of a 2.9-mm-diameter implant using a fatigue limit test and to investigate the Morse effect of 2 different Morse taper systems, 2.

Effect of cavity preparation design and ceramic type on the stress distribution, strain and fracture resistance of CAD/CAM onlays in molars.

Objective This study aimed to evaluate the effect of the cavity preparation and ceramic type on the stress distribution, tooth strain, fracture resistance and fracture mode of human molar teeth restored with onlays. Material and Methods Forty-eight molars were divided into four groups (n=12) with assorted combinations of two study factors: BL- conventional onlay preparation with boxes made from leucite ceramic (IPS-Empress CAD, Ivoclar Vivadent); NBL- conservative onlay preparation without boxes made from leucite ceramic; BD- conventional onlay preparation with boxes made from lithium disilicate glass ceramic (IPS e.max CAD, Ivoclar Vivadent); NBL- conservative onlay preparation with boxes made from lithium disilicate glass ceramic cuspal deformation (µS) was measured at 100 N and at maximum fracture load using strain gauge.

Influence of scanner, powder application, and adjustments on CAD-CAM crown misfit.

Statement Of Problem: The manufacturers of computer-aided design and computer-aided manufacturing (CAD-CAM) systems emphasize that new technologies can improve the marginal fit of dental crowns. However, data supporting this claim are limited.

Purpose: The purpose of this in vitro study was to investigate the differences among the following fabrication methods on the marginal discrepancy of dental crowns: intraoral optical scanners, powder application, and adjustments of intaglio surface.

Microleakage at Different Implant-Abutment Connections Under Unloaded and Loaded Conditions.

Purpose: This study evaluated the microleakage at different implant-abutment (I-A) connections under unloaded and loaded conditions.

Materials And Methods: Forty implants, specially designed with an opening at the apex, were grouped according to the I-A and screw device: external hexagon implants with titanium (EH) or EH diamond-like carbon screws fixing the abutment; internal hexagon implants with titanium screws (IH); and Morse taper implants with solid (MT) or MT passing screws (MTps) abutments. The implants were fixed in a 2-compartment device, and toluidine blue solution (1.

Influence of indexed abutments on the fracture resistance of internal conical dental implants.

The aim of this study was to evaluate the influence of abutments with a prosthetic index on the fracture resistance of Morse taper dental implants. Morse taper implants were divided into 2 groups (n = 5 per group): a group with an indexed implant and a nonindexed abutment (solid Morse taper universal post; WIS group), and a group with an indexed implant and an indexed abutment (WIP group). Both groups were subjected to bending tests for fracture strength until 5 mm of displacement or implant fracture occurred.

Effects of new implant-retained overdentures on masticatory function, satisfaction and quality of life.

The aim of this study is to evaluate the effects of replacing poorly fitting dentures on patient's masticatory function, satisfaction and oral health-related quality of life. Fourteen patients with conventional maxillary complete dentures and mandibular overdentures retained by two implants bar clip system had their dentures replaced. The laboratory tests for the analysis of masticatory performance were conducted using an "Optocal" food simulator test.

Precision Fit of Screw-Retained Implant-Supported Fixed Dental Prostheses Fabricated by CAD/CAM, Copy-Milling, and Conventional Methods.

Purpose: The aim of this study was to evaluate the effectiveness of fabrication methods (computer-aided design/computer-aided manufacture [CAD/CAM], copy-milling, and conventional casting) in the fit accuracy of three-unit, screw-retained fixed dental prostheses.

Materials And Methods: Sixteen three-unit implant-supported screw-retained frameworks were fabricated to fit an in vitro model. Eight frameworks were fabricated using the CAD/CAM system, four in zirconia and four in cobalt-chromium.

Bacterial Adhesion and Surface Roughness for Different Clinical Techniques for Acrylic Polymethyl Methacrylate.

This study sought to assess the effect of different surface finishing and polishing protocols on the surface roughness and bacterial adhesion (S. sanguinis) to polymethyl methacrylates (PMMA). Fifty specimens were divided into 5 groups (n = 10) according to their fabrication method and surface finishing protocol: LP (3 : 1 ratio and laboratory polishing), NF (Nealon technique and finishing), NP (Nealon technique and manual polishing), MF (3 : 1 ratio and manual finishing), and MP (3 : 1 ratio and manual polishing).

Bone Remodeling Around Implants with External Hexagon and Morse-Taper Connections: A Randomized, Controlled, Split-Mouth, Clinical Trial.

Objectives: To evaluate clinical, radiographic, microbiologic, and biomechanical parameters related to bone remodeling around implants with external hexagon (EH) and Morse-taper (MT) connections.

Materials And Methods: Twelve totally edentulous patients received four custom-made implants in the interforaminal region of the mandible. Two of those implants had the same macroscopic design, but different prosthetic connections.

Fracture Resistance of Internal Conical and External Hexagon: Regular and Narrow Implant-Abutment Assemblies.

Purpose: The aim of this study was to compare the maximum load on the elastic limit of internal conical (IC) implants with regular external hexagon (REH) and narrow external hexagon (NEH) implants.

Materials And Methods: Thirty cylindrical implants were divided in 3 groups (n = 10): REH (3.75 mm); NEH (3.

Stress Over Implants of One-Piece Cast Frameworks Made With Different Materials.

This study aims to compare stress transmitted to implants and passive fit of one-piece cast frameworks fabricated with 3 different materials: commercially pure titanium (G1-CP Ti), cobalt-chromium alloy (G2-Co-Cr), and nickel-chromium-titanium alloy (G3-Ni-Cr-Ti). In total, 12 frameworks simulating bars for fixed prosthesis in a model with 5 implants were fabricated. The passive fit of the framework interface was measured using an optical microscope and the stresses transmitted to implants were measured using quantitative photoelastic analysis.

A conservative approach to retrieve a fractured abutment screw - Case report.

Introduction: Regarding implant-supported prostheses, the most reported types of complications are related to loosening or fracturing of abutment or prosthesis screws. This case report shows a series of procedures that allowed a conservative solution for a fractured screw. It avoided removing the implant and also allowed the same prosthesis to be used after guided-drilling the fractured screw and re-tapping the implant internal threads.

Influence of the Prosthetic Index Into Morse Taper Implants on Bacterial Microleakage.

Purpose: To evaluate the influence of Morse taper implant index on microleakage.

Materials And Methods: Thirty implants and abutments were divided into 3 groups (n = 10): CM1 (universal post and implant without index), CM2 (universal post and implant with index), and CM3 (abutment and implant with index). To evaluate the microleakage from the implant inner part, the implants were inoculated with Streptococcus sanguinis solution at a 0.

Microcomputed tomography marginal fit evaluation of computer-aided design/computer-aided manufacturing crowns with different methods of virtual model acquisition.

This in vitro study used microcomputed tomography to evaluate the marginal fit of crowns fabricated using a chairside computer-aided design/computer-aided manufacturing (CAD/CAM) system with different methods of virtual model acquisition. Crowns were fabricated to fit in a cast containing a single human premolar. Four methods of virtual model acquisition were used: Group 1 (control), digital impressioning of a typodont; Group 2, digital impressioning of a powdered typodont; Group 3, digital impressioning of a regular impression; and Group 4, digital impressioning of a master cast.

Placement of a distal implant to convert a mandibular removable Kennedy class I to an implant-supported partial removable Class III dental prosthesis: A systematic review.

Statement Of Problem: A number of authors have reported the placement of a distal implant associated with a partial removable dental prosthesis (PRDP) to make this rehabilitation more stable. This strategy may represent an option for resolving the problem of the intrusive movements of the PRDP and for reducing treatment costs.

Purpose: The purpose of this systematic review was to evaluate the current evidence about the placement of a distal implant associated with a mandibular PRDP to improve patient satisfaction and the clinical performance of the abutment tooth and distal implant.

Strain analysis of different diameter Morse taper implants under overloading compressive conditions.

The aim of this study was to evaluate the amount of deformation from compression caused by different diameters of Morse taper implants and the residual deformation after load removal. Thirty Morse taper implants lacking external threads were divided into 3 groups (n = 10) according to their diameter as follows: 3.5 mm, 4.