OBJECTIVE The aim of this study was to evaluate the effect of simulated periodontal ligament (SPDL) on custom cast dowel and core removal by ultrasonic vibration. MATERIAL AND METHODS Thirty-two human maxillary canines were included in resin cylinders with or without SPDL made from polyether impression material. In order to allow tensile testing, the roots included in resin cylinders with SPD...

Precise transfer of three-dimensional position of dental implants from oral cavity to the cast needs special considerations in impression making. It has been suggested to splint the copings by bars or acrylic resin material before making impression. Some problems regarding to polymerization shrinkage of acrylic resin have been reported. In this study, we describe a metalacrylic bar tha...

Early history of dentin bonding Attempts to develop an adhesive system which bonds acrylic resins to the tooth structure started in the early 1950s. In 1949, an adhesive system capable of bonding acrylic resin to the tooth structure was invented by Hagger; it was composed of glycerophosphoric acid dimethacrylate (GPDM) and sulfinic acid as the catalyst. In his patent, shear bond strengths of ac...

The aim of this study is to clarify the effect of different concentrations of titanium dioxide nanoparticles (Nps) on the properties of two types of heat polymerized acrylic resin. The tested parameters were flexural strength, impact strength, and microhardness. The two types of acrylic resin used in this study were conventional unmodified (Implacryl, Vertex) and high impact heat polymerized ac...

Correspondence to: Wagner Araújo de Negreiros University of Campinas – Piracicaba Dental School Department of Prosthodontics and Periodontology Av. Limeira 901, CEP: 13414-903 Piracicaba Brazil Telephone: (19) 3435-1233 E-mail: [email protected] Abstract Keeping the flask closed may reduce the stress released by the resin dough after the pressing step, preserving the tooth relationship ...

Ar/O2/N2 cold plasma was employed to treat the surface of heat-curing acrylic resin, and the wettability changes were evaluated. After plasma treatment, the contact angle reduced significantly. XPS results indicated that the C/O ratio reduced and a new hydrophilic group C–OH was generated on the surface of acrylic resin.

AIM The aim of this in vitro study was to compare the change in the retentive force and removal torque of three attachment systems during simulation of insertion-removal cycles. METHODOLOGY Edentulous mandibular models were made with heat-cured polymethyl methacrylate resin. Two implant replicas (CMI), of 3.75 mm diameter and 10 mm length, were placed in the intraforaminal region. Acrylic res...

This in vitro study compared different ultrasonic vibration modes for intraradicular cast post removal. The crowns of 24 maxillary canines were removed, the roots were embedded in acrylic resin blocks, and the canals were treated endodontically. The post holes were prepared and root canal impressions were taken with self-cured resin acrylic. After casting, the posts were cemented with zinc phos...

Background: (PMMA) has been used in dental prosthetic devices for almost 70 years; three features have contributed for its success: excellent appearance, simple processing technique and easy repair. However, the resistance to impact and fracture of PMMA during function is low. Various methods for enhancing strength of the acrylic resin denture bases have been reported. This study was designed t...