Bacterial infiltration and detorque at the implant abutment morse taper interface after masticatory simulation.

This study evaluated the bacterial infiltration and the detorque of indexed and non-indexed abutments of Morse taper implants (MTI) after mechanical cycling (MC). 40 MTI were distributed into four groups: IIA (indexed implant abutments); NIIA (non-indexed implant abutments); IIAMC (indexed implant abutments submitted to MC); NIIAMC (non-indexed implant abutments submitted to MC), which were carried out under one million 5 Hz frequency and 3 Bar pressure. After mechanical cycling, all groups were immersed in a bacterial solution in Brain Heart Infusion Agar.

Development and validation of new methodologies for teaching preparations in fixed partial prosthesis.

Context: Students can have some issues in the comprehension and execution of coronal preparations in fixed partial prosthesis (FPP). Some issues pertain to the amount of reduction, the inclination, and the positioning, all of which are important for the execution of an ideal preparation while respecting the required biomechanical principles.

Objective: The present study's aim was to evaluate the main problems experienced by graduation students regarding coronal preparation in FPP and to suggest teaching skills to help students and professors.

A 10-Year Follow-Up of Different Intra-Radicular Retainers in Teeth Restored with Zirconia Crowns.

Purpose: To evaluate the survival rate in restored teeth with three different types of retainers prior to the fixing of crowns with zirconia through this retrospective clinical study. It is unclear how the type of post and core rehabilitation, and type of resin cement affect the longevity of teeth restored with crowns.

Methods: In a private clinic, a total of 101 retainers installed by the same professional between June 2008 and January 2018, with an average time of 58.

Evaluation of the Accuracy of Conventional and Digital Impression Techniques for Implant Restorations.

Purpose: The increased use of CAD systems can generate doubt about the accuracy of digital impressions for angulated implants. The aim of this study was to evaluate the accuracy of different impression techniques, two conventional and one digital, for implants with and without angulation.

Materials And Methods: We used a polyurethane cast that simulates the human maxilla according to ASTM F1839, and 6 tapered implants were installed with external hexagonal connections to simulate tooth positions 17, 15, 12, 23, 25, and 27.

Strain Gauge Evaluation of Transfer Impression Techniques of Multiple Implant-Supported Prosthesis.

Purpose: This in vitro study assessed the accuracy of multiple implant-level impression techniques (open tray and closed tray) for the fabrication of 3-unit implant prostheses with strain gauge (SG) analysis.

Materials And Methods: A polyurethane master model was designed to simulate a clinical situation. Two rigid custom trays were fabricated for the model.

Zirconia Rehabilitation Focused on the Emergence Profile: A Case Report.

The first choice for anterior rehabilitation has been metal-free materials due to their successful aesthetic results. However, the definitive clinical work accuracy may be affected by the lack of clinicians' expertise and familiarization with the latest techniques, as well as recurrent laboratory procedures. This manuscript presents a clinical experience with zirconia ceramic for anterior crowns and zirconia CAD/CAM abutments, including both clinical and laboratory steps after the implant installation.

Effect of Different Abutments and Connections in Deformation Crestal Bone.

Statement Of Problem: The use of Morse taper connections is increasing, but little is known about the biomechanical use of abutments and their use in fixed prostheses.

Purpose: This study evaluated the transmission of load on the bone implant-supported dentures, varying the type of prosthetic connection and abutment.

Material And Methods: Using 4 polyurethane models, 3 implants were inserted into each block, establishing the following groups: (a) external hexagon and Micro-Unit abutments; (b) external hexagon and UCLA abutment; (c) Morse taper and Micro-Unit abutments; and (d) Morse taper and UCLA abutments.

Effect of Jig Design and Assessment of Stress Distribution in Testing Metal-Ceramic Adhesion.

Purpose: In testing adhesion using shear bond test, a combination of shear and tensile forces occur at the interface, resulting in complex stresses. The jig designs used for this kind of test show variations in published studies, complicating direct comparison between studies. This study evaluated the effect of different jig designs on metal-ceramic bond strength and assessed the stress distribution at the interface using finite element analysis (FEA).

A microstrain comparison of passively fitting screw-retained and cemented titanium frameworks.

Statement Of Problem: An imprecise fit between frameworks and supporting dental implants in loaded protocols increases the strain transferred to the periimplant bone, which may impair healing or generate microgaps.

Purpose: The purpose of this study was to investigate the microstrain between premachined 1-piece screw-retained frameworks (group STF) and screw-retained frameworks fabricated by cementing titanium cylinders to the prefabricated framework (group CTF). This procedure was developed to correct the misfit between frameworks and loaded implants.

Screw spreading: technical considerations and case report.

The spreading system is an alternative technique to the Summers osteotome. The crest expansion technique is a less invasive procedure in which the facial wall expands after the medullary bone is compressed against the cortical wall. It improves the density of the maxillary bone, which allows for greater initial stability of implants.

Influence of surface treatment on the shear bond strength of ceramics fused to cobalt-chromium.

Purpose: To evaluate the influence of surface treatment on the shear bond strength between a Co-Cr alloy and two ceramics.

Materials And Methods: Forty-eight metal cylinders were made (thickness: 4 mm, height: 3.7 mm) according ISO TR 11405.

Penetration of 35% hydrogen peroxide into the pulp chamber in bovine teeth after LED or Nd:YAG laser activation.

This aim of the present study was to evaluate the pulp chamber penetration of 35% hydrogen peroxide activated by LED (light-emitting diode) or Nd:YAG laser in bovine teeth, after an in-office bleaching technique. Forty-eight bovine lateral incisors were divided into four groups, acetate buffer was placed into the pulp chamber and bleaching agent was applied as follows: for group A (n = 12), activation was performed by LED; for group B (n = 12), activation was performed by Nd:YAG laser (60 mJ, 20 Hz); group C (n = 12) received no light or laser activation; and the control group (n = 12) received no bleaching gel application or light or laser activation. The acetate buffer solution was transferred to a glass tube and Leuco Crystal Violet and horseradish peroxidase were added, producing a blue solution.

In vitro evaluation of the precision of working casts for implant-supported restoration with multiple abutments.

Objective: The purpose of this study was to compare the accuracy of two working cast fabrication techniques using strain-gauge analysis.

Methods: Two working cast fabrication methods were evaluated. Based on a master model, 20 working casts were fabricated by means of an indirect impression technique using polyether after splinting the square transfer copings with acrylic resin.