The effect of surface treatment and low-temperature degradation on flexural strength of additive manufactured zirconia.

This study aimed to assess the effect of low-temperature degradation (LTD) and surface treatment on the flexural strength of additive-manufactured (AM) zirconia by comparison to subtractive-manufactured (SM) zirconia. Disc-shaped zirconia specimens were fabricated using AM and SM technology, and each group was assigned to 3 subgroups according to the type of surface treatment: control, sandblasting (SB), and 9% hydrofluoric acid etching (HF). The groups were then further divided into 2 subgroups: unaged and aged.

Effect of 9% Hydrofluoric Acid Gel Hot-Etching Surface Treatment on Shear Bond Strength of Resin Cements to Zirconia Ceramics.

Background and Objectives: There is no consensus regarding the surface treatment method for achieving optimal bonding strength between zirconia and resin cements. We evaluated the effect of hot-etching with 9% hydrofluoric acid (HF) gel using the Zirconia Etchant Cloud System on zirconia surfaces and the consequent shear bond strength (SBS) of different resin cements to such surface-treated zirconia ceramics. Materials and Methods: Forty-five zirconia specimens were randomly assigned to surface-treatment groups (n = 15/group): no treatment (control, CT); sandblasting with 110-μm Al2O3 at an air pressure of 1 bar for 10 s (SB); hot-etching with 9% HF gel (HE).

Survival Rates and Clinical Outcomes of Implant Overdentures in Old and Medically Compromised Patients.

Studies on the survival rate of implant overdentures in medically compromised patients are limited because most studies exclude patients with systemic diseases affecting implant prognosis. This retrospective study aimed to evaluate the survival rate and clinical outcomes of dental implants used for overdentures in medically compromised patients. A total of 20 patients (9 men, 11 women; mean age: 67.

Effect of topographical control by a micro-molding process on the activity of human Mesenchymal Stem Cells on alumina ceramics.

Background: Numerous studies have reported that microgrooves on metal and polymer materials can affect cell adhesion, proliferation, differentiation and guidance. However, our knowledge of the cell activity associated with microgrooves on ceramics, such as alumina, zirconia, hydroxyapatite and etc, is very incomplete, owing to difficulties in the engraving of microgrooves on the hard surface of the base material. In this study, microgrooves on alumina were fabricated by a casting process using a polydimethylsiloxane micro-mold.

The effect of resin cements and primer on retentive force of zirconia copings bonded to zirconia abutments with insufficient retention.

Purpose: The purpose of this study was to investigate the effect of resin cements and primer on the retentive force of zirconia copings bonded to zirconia abutments with insufficient retention.

Materials And Methods: Zirconia blocks (Lava, 3M ESPE, St. Paul, MN, USA) were obtained and forty sets of zirconia abutments and copings were fabricated using CAD/CAM technology.

Secondary closure of an extraction socket using the double-membrane guided bone regeneration technique with immediate implant placement.

Purpose: Immediate implantation presents challenges regarding site healing, osseointegration, and obtaining complete soft-tissue coverage of the extraction socket, especially in the posterior area. This last issue is addressed herein using the double-membrane (collagen membrane+high-density polytetrafluoroethylene [dPTFE] membrane) technique in two clinical cases of posterior immediate implant placement.

Methods: An implant was placed immediately after atraumatically extracting the maxillary posterior tooth.

Evaluation of Spinal Fusion Using Bone Marrow Derived Mesenchymal Stem Cells with or without Fibroblast Growth Factor-4.

Objective: In this study, the authors assessed the ability of rat bone marrow derived mesenchymal stem cells (BMDMSCs), in the presence of a growth factor, fibroblast growth factor-4 (FGF-4) and hydroxyapatite, to act as a scaffold for posterolateral spinal fusion in a rat model.

Methods: Using a rat posterolateral spine fusion model, the experimental study comprised 3 groups. Group 1 was composed of 6 animals that were implanted with 0.

An in vivo comparison of working length determination by only root-ZX apex locator versus combining root-ZX apex locator with radiographs using a new impression technique.

Objective: The objective of this study was to compare, in vivo, the accuracy of working length determination using only the Root-ZX electronic apex locator versus adjusting Root-ZX measurements after obtaining a working length radiograph.

Study Design: The working length was determined in 25 premolar root canals using Root-ZX and K-files were fixed at these positions. Radiographs were acquired and interpreted, and the recorded working length measurement was adjusted, if necessary, for a combined measurement.

Nanosized hydroxyapatite powder synthesized from eggshell and phosphoric acid.

The present research describes synthesis of highly sinterable, nano-sized hydroxyapatite (HAp) powders using a wet chemical route with recycled eggshell and phosphoric acid as calcium and phosphorous sources. The raw eggshell was easily turned to CaO by the calcining process, and phosphoric acid was mixed with the calcined eggshell by the wet, ball-milling method. The crystalline development and microstructures of the synthesized powders and sintered samples were examined by X-ray diffractometry and scanning electron microscopy, respectively.

Properties and cyclic fatigue of glass infiltrated tape cast alumina cores produced using a water-based solvent.

Objective: The purpose of this study was to investigate the properties of tape cast alumina composite produced using a water-based solvent and its possible clinical use as an all ceramic crown system in a fixed partial denture. Durability of the system will be measured by fatigue test to simulate the masticating conditions of the oral cavity.

Methods: The optimal weight ratio of water-based alumina tape was determined by tensile strength, shrinkage ratio and durability.