Biomedical subjects

Paul D Hammesfahr

Publications and source records attributed to Paul D Hammesfahr.

3 recordsLinked to original sources

PubMed2006

Building the edentulous impression--a layering technique using multiple viscosities of impression material.

The purpose of this article is to introduce a novel impression technique. The procedure demonstrates a building, or layering, method of impression making that maintains the integrity between layers of the impression materials of varying viscosities and controls the path of insertion, minimizing the incidence of overextension. To build a detailed impression of the tissue-bearing surfaces, the clinician selects the proper viscosity of impression material based on the diagnosed tissue condition.

Dental Impression Materials↗

PubMed2004

An accelerated in vitro model for adhesive testing.

PURPOSE: To develop a pilot in vitro accelerated laboratory testing protocol for assessing marginal sealing capability of dental adhesives. METHODS: Occlusal cavities were prepared in 20 human molar teeth and restored with Spectrum TPH resin composite. Prime & Bond NT and Prompt L-Pop served as the adhesive for eight teeth each. An experimental self-etching adhesive system was used on the remaining four teeth. Each specimen was subjected in sequential fashion to the following challenges: 400,000 wear cycles in a Leinfelder simulator; 5000 thermocycles between water baths maintained at 5 degrees C and 55 degrees C with a dwell time of 40 seconds in each; and a repetition of the 400,000 wear cycles. Polyvinyl siloxane impressions were made at baseline and after each challenge. Microleakage was assessed following silver nitrate staining and marginal degradation was evaluated using light microscopy and the stone casts made from the impressions taken during the project. RESULTS: Microleakage analysis yielded the following median leakage values: Prime & Bond NT - 0; Prompt L-Pop - 1; and experimental self-etching adhesive - 3. The Wilcoxon sign rank test demonstrated significant differences between all three adhesives (P < or = 0.05). Evaluation of the stone casts demonstrated that marginal gaps were more prevalent after the second wear challenge.

Acid Etching, Dental↗

PubMed2002

Light-curing technology: past, present, and future.

The availability of light-curable resin systems has led to the development of a variety of technologies for producing the light necessary to cure them. Light, being electromagnetic radiation, is comprised of a wide spectrum of energies including ultraviolet, visible, and infrared. Each wavelength region of light has different characteristics in terms of chemical reactions, most notably polymerization of dental materials. Quartz tungsten halogen, plasma arc curing, laser, and, recently, light-emitting diode have all been important technologies used to produce light through dental curing units. Each technology has unique advantages and disadvantages. Thus, it is important for dental professionals to understand the polymerization processes and the ways in which these processes are affected by light energy.

Composite Resins↗