Evaluation of the Effect of Air Polishing With Different Abrasive Powders on the Roughness of Implant Abutment Surface: An In Vitro Study.

The aim of this in vitro study was to evaluate the effect of air polishing on the implant abutment surface using different abrasive powders: sodium bicarbonate and amino acid glycine. Fifteen grade III machined surface titanium disks with 8-mm diameter and 2-mm thickness were divided in 3 groups of 5 samples each and subjected to air polishing for 20 seconds with an Ultrajet Flex air-abrasive device and a distinct prophylaxis protocol: air and water (G1); air, water, and sodium bicarbonate (G2); and air, water; and amino acid glycine (G3). After the air polishing, the average roughness (Ra) of the samples was measured using an optical profilometer, and the obtained data were statistically analyzed.

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.

Influence of different maintenance times of torque application on the removal torque values to loosen the prosthetic abutment screws of external hexagon implants.

Purpose: To analyze the torque application on prosthetic abutment screws using different maintenance times, to determine an influence on the removal torque values.

Materials And Methods: A total of 40 external hexagon implants, 40 titanium screws, and 40 customized abutments were used. In group 1, the screws received a torque of 30 N·cm by instant torque application; in groups 2, 3, and 4, torque of 30 N·cm was applied and maintained for 10, 20, and 30 seconds, respectively.

Strain gauge analysis of the effect of porcelain firing simulation on the prosthetic misfit of implant-supported frameworks.

Objectives: This study investigated the effect of porcelain firing on the misfit of implant-supported frameworks and analyzed the influence of preheat treatment on the dimensional alterations.

Materials And Methods: Four external-hex cylindrical implants were placed in polyurethane block. Ten frameworks of screw-retained implant-supported prostheses were cast in Pd-Ag using 2 procedures: (1) control group (CG, n = 5): cast in segments and laser welded; and test group (TG, n = 5): cast in segments, preheated, and laser welded.

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.

Effect of cast rectifiers on the marginal fit of UCLA abutments.

Objectives: This study assessed the effect of cast rectifiers on the marginal misfit of cast UCLA abutments compared to premachined UCLA abutments. The influence of casting and porcelain baking on the marginal misfit of these components was also investigated.

Methods: Two groups were analyzed: test group - 10 cast UCLA abutments, finished with cast rectifier and submitted to ceramic application; control group - 10 premachined UCLA abutments, cast with noble metal alloy and submitted to ceramic application.

A new device in immediately loaded implant treatment in the edentulous mandible.

Purpose: This article reports preliminary clinical results of the Speed Master system, a method for immediate loading of implants for the treatment of mandibular edentulism.

Materials And Methods: Fifteen patients with edentulous mandibles were consecutively included in the study. Each received 4 implants between the mental foramina placed using the system's surgical guides.

The influence of different screw tightening forces on the vertical misfit of implant-supported frameworks.

Objectives: The present in vitro study was designed to compare the differences in the vertical misfit of implant-supported frameworks using three different forces for tightening the bridge locking screws: fastening by hand until first resistance, and using torque drivers with 10 and 20Ncm.

Methods: The investigation was conducted based on the results given by 9 six-unit nickel-chromium (2 abutments/ 4 pontics) screw-retained implant-supported frameworks. The structures were exposed to simulated porcelain firings.