Interfacial Characteristics and Bond Durability of Universal Adhesive to Various Substrates.

Objective: This study investigated the interfacial characteristics and bond durability of universal adhesives to various substrates.

Methods And Materials: Two universal adhesives were used: 1) Scotchbond Universal and 2) G-Premio Bond. The substrates used were bovine enamel and dentin with or without phosphoric acid etching, resin composite, lithium disilicate and leucite-reinforced glass ceramics, zirconia, and metal alloys.

Wear rates of resin composites.

SUMMARY A laboratory study was conducted to examine the wear of resin composite materials using a generalized wear simulation model. Ten specimens each of five resin composites (Esthet•X [EX], Filtek Supreme Plus [SP], Filtek Z250 [Z2], Tetric EvoCeram [EC], and Z100 Restorative [Z1]) were subjected to wear challenges of 100,000, 400,000, 800,000, and 1,200,000 cycles. The materials were placed in cylinder-shaped stainless-steel fixtures, and wear was generated using a flat stainless-steel antagonist in a slurry of polymethylmethacrylate beads.

Lysophosphatidic Acid signals through specific lysophosphatidic Acid receptor subtypes to control key regenerative responses of human gingival and periodontal ligament fibroblasts.

Background: We showed that the pluripotent platelet growth factor and mediator lysophosphatidic acid (LPA) controls key regenerative responses of human gingival fibroblasts (GFs) and periodontal ligament fibroblasts (PDLFs) and positively modulates their responses to platelet-derived growth factor (PDGF). This study determined which LPA receptor (LPAR) subtype(s) LPA signals through to stimulate mitogenic extracellular signal-regulated kinase (ERK) 1/2 signaling and chemotaxis and to elicit intracellular Ca(2+) increases in GFs and PDLFs because many healing responses are calcium-dependent.

Methods: Activation of mitogen-activated protein kinase was determined using Western blotting with an antibody to phosphorylated ERK1/2.

Effect of enamel etching time on roughness and bond strength.

The current study examined the effect of different enamel conditioning times on surface roughness and bond strength using an etch-and-rinse system and four self-etch adhesives. Surface roughness (Ra) and composite to enamel shear bond strengths (SBS) were determined following the treatment of flat ground human enamel (4000 grit) with five adhesive systems: (1) Adper Single Bond Plus (SBP), (2) Adper Prompt L-Pop (PLP), (3) Clearfil SE Bond (CSE), (4) Clearfil S3 Bond (CS3) and (5) Xeno IV (X4), using recommended treatment times and an extended treatment time of 60 seconds (n = 10/group). Control groups were also included for Ra (4000 grit surface) and SBS (no enamel treatment and Adper Scotchbond Multi-Purpose Adhesive).

Wear simulation of resin composites and the relationship to clinical wear.

This study used a new generalized wear model to examine the relationship between wear simulation and the clinical wear of two resin composites. Ten specimens each of P50 and Z100, were subjected to 100,000, 400,000 and 800,000 cycles in a spring-loaded piston-type wear simulator. Wear was generated using flat, cylindrically-shaped stainless steel antagonists on the resin composites, which were placed in custom stainless steel fixtures.

Cement selection for cement-retained crown technique with dental implants.

Purpose: The purpose of this study was to assess and compare the retentive nature of common dental cements that have been adapted for use in the implant abutment cement-retained crown (CRC) technique with those specifically formulated for this purpose.

Materials And Methods: Ten regular diameter implant analogs were embedded in stainless steel disks. Unmodified CRC abutments were attached and torqued to 30 Ncm.

Accuracy of a fixed value nasion relator in facebow design.

Purpose: This study examined whether a fixed value nasion relator accurately locates the orbitale in a patient population.

Materials And Methods: The mean value for the vertical distance between soft tissue nasion and orbitale was determined through the analysis of cephalometric radiographs of 114 adult patients. This value was then compared to a facebow design, which uses a fixed value of 25.

Lysophosphatidic acid modulates the healing responses of human periodontal ligament fibroblasts and enhances the actions of platelet-derived growth factor.

Background: Platelet-derived growth factor (PDGF) has been used to promote healing in many in vitro and in vivo models of periodontal regeneration. PDGF interacts extensively with lysophosphatidic acid (LPA). We recently showed that LPA modulates the responses of human gingival fibroblasts to PDGF.

Localized wear of compomer restorative materials.

Purpose: To determine and compare the localized wear of six compomer restorative materials.

Materials And Methods: Ten specimens of Dyract, Dyract AP, F2000, Compoglass F, Elan and Hytac were prepared in a custom fixture and polished. A pretest surface profile was generated using an MTS 3-D surface profilometer and the specimens were subjected to 400,000 cycles in a Leinfelder wear machine equipped with a conical stylus tip to simulate localized wear.

Use of electrosurgery and lasers in the presence of dental implants.

Use of electrosurgery or laser surgery in the presence of metallic implants has been implicated in generating heat-induced injury to peri-implant bone, with the subsequent loss of osseointegration. Studies involving lasers offer conflicting results, while in the case of the electrosurg, little research has been published supporting or refuting these claims. This study measured local heat effects created by use of a unipolar electrosurgical unit, a bipolar electrosurgical unit, and a neodymium:yttrium-aluminum-garnet (Nd:YAG) laser.

Evaluation of porcelain surface treatments and agents for composite-to-porcelain repair.

Intraoral repairs often involve bonding composite to fractured porcelain. Newer adhesive systems, currently referred to as multipurpose systems, include materials with recommended procedures for repair of porcelain. This laboratory study evaluated various treatment regimens with the ProBond adhesive system.

4-year clinical study of castable ceramic crowns.

Purpose: To evaluate the 4-year clinical performance of castable glass ceramic crowns used to restore teeth in the posterior segments.

Materials And Methods: 101 castable ceramic (Dicor) full++ crown restorations were placed in 61 molar and 40 premolar teeth using a bonded resin cement.

Results: After 4 years of clinical performance, 15 of the original 101 restorations were known to have failed with 13 of those failures affecting molar restorations.

Effect of porcelain surface treatments on bond strengths of composite resin bonded to porcelain.

A laboratory study was conducted to evaluate the bond strength of composite resin bonded to porcelain surfaces by use of a variety of treatment regimens with the All-Bond 2 adhesive system. There were significant differences in the 24-hour bond strengths between several of the surface treatment methods. The mean shear bond strength after 24 hours of water storage ranged from 10.

Bond strength of composite resin to porcelain with newer generation porcelain repair systems.

A laboratory study was conducted to evaluate the mean shear bond strength of composite resin bonded to porcelain with the use of eight newer generation repair systems. The range of shear bond strength after 24 hours of water storage was 23.5 +/- 5.

Comparative efficiency testing 330 carbide dental burs utilizing Macor substrate.

Traditionally, it has been difficult to compare the clinical performance of carbide dental burs. The purpose of this laboratory study was to investigate the comparative cutting efficiency of number 330 dental burs from six manufacturers. These burs were tested utilizing custom-built equipment consisting of a frictionless air sled to which the Macor substrate was attached.