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Biomedical subjects

W P Kelsey

Publications and source records attributed to W P Kelsey.

At least 19 recordsLinked to original sources
PubMed1996

Bond strengths to enamel and dentin with indirect and direct resin composites.

PURPOSE: To investigate the differences in shear bond strengths between indirect and direct resin composites attached to enamel and dentin. MATERIALS AND METHODS: Sixty human molar teeth stored in distilled water since extraction were used in this study. Thirty of the teeth were prepared to form a flat enamel surface ground to 600 grit and 30 of the teeth were prepared to form a flat dentin surface ground to 600 grit. Cylinders constructed from Triad indirect resin composite were bonded to 15 enamel and 15 dentin surfaces and additional cylinders constructed from TPH direct resin were bonded to the remaining 15 enamel and 15 dentin substrates. Bond strengths were determined by shearing the specimens with an Instron testing machine. RESULTS: Mean shear bond strengths observed in this study were: Triad to enamel, 27.64 +/- 7.35 MPa; TPH to enamel, 27.43 +/- 3.37 MPa; Triad to dentin, 21.83 +/- 3.10 MPa; and TPH to dentin, 21.27 +/- 4.85 MPa. Two-way ANOVA demonstrated that significant differences existed between the four test groups and that this difference was primarily related to the surface to which the cylinders were attached (P = 0.000). No significant differences were discovered in shear bond strengths between restorative materials (P = 0.767) or between restorative materials bonded to a specific, common surface (P = 0.891). Turkey's post hoc test demonstrated that the shear bond strength of Triad to enamel was significantly greater than the shear bond strength of either Triad to dentin (P = 0.012) or TPH to dentin (P = 0.005). This test also pointed out that the shear bond strength of TPH to enamel was significantly greater than the shear bond strength of either TPH to dentin (P = 0.007) or Triad to dentin (P = 0.016). Finally, it was noted that the shear bond strength of Triad to enamel was essentially the same as TPH to enamel (P = 1.000) and that the bond strength of Triad to dentin was essentially the same as TPH to dentin (P = 0.990).

Acrylic Resins↗
PubMed1995

Bond strength of an adhesive resin system with various dental substrates.

A laboratory study was conducted to evaluate the Panavia 21 resin-based adhesive system as a bonding agent between a variety of dental substrates. Panavia 21 resin was bonded directly to enamel and dentin and placed between nickel-chromium-beryllium (Ni-Cr-Be) specimens and enamel, dentin, other Ni-Cr-Be samples, and type III gold. Panavia 21 resin was also used to bond amalgam to dentin. Shear bond strengths were determined at 24 hours and after thermocycling at 3 months. The results of this study at both the 24-hour and the 3-months test periods indicate that the enamel bond strengths of Panavia 21 resin (24 hours, 19.3 +/- 5.5 MPa; 3 months, 23.7 +/- 4.4 MPa) exceeded its dentin bond strengths (24 hours, 7.8 +/- 1.4 MPa; 3 months, 8.8 +/- 3.2 MPa). The bond strengths between Panavia 21 resin and Ni-Cr-Be alloy (24 hours, 16.3 +/- 3.4 MPa; 3 months, 17.6 +/- 2.7 MPa) and those for Panavia 21 resin between Ni-Cr-Be alloy and dentin (24 hours, 18.7 +/- 4.2 MPa; 3 months, 19.8 +/- 5.3 MPa) were comparable to adhesive enamel bond strengths. High bond strengths were also generated by Panavia 21 resin between Ni-Cr-Be alloy and type III gold (24 hours, 39.3 +/- 5.9 MPa; 3 months, 35.5 +/- 7.1 MPa). The greatest bond strengths observed during both test time periods for Panavia 21 resin were between Ni-Cr-Be alloy and enamel (24 hours, 54.2 +/- 10.7 MPa; 3 months, 56.4 +/- 7.1 MPa) and between two samples of Ni-Cr-Be alloy (24 hours, 55.1 +/- 5.6 MPa; 3 months, 49.1 +/- 8.6 MPa). Panavia 21 resin produced high bond strengths between a variety of dental substrates commonly used for the placement of fixed prosthodontic restorations.

Adhesives↗
PubMed1995

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. All serviceable restorations were rated as excellent for color match, margin adaptation, proximal contact and gingival health. Cavosurface margin discoloration received a 93.5% alfa response. The results of this study show that Dicor crowns meet the esthetic and biological requirements for posterior restorations. The incidence of fracture of molar restorations in this study indicated that when used for restoring molars, careful case selection and caution must be employed.

Adult↗
PubMed1994

Power density and external temperature of laser-treated root canals.

The purpose of this study was to determine the power and time parameters for an argon laser that would result in the removal of pulpal tissue without excessively elevating the external temperature of the root. External temperatures were measured by attaching thermistors to the surfaces of the teeth at the cemento-enamel junction (CEJ) areas and at the root apices. Results indicate that a 1-W power setting with a pulse duration of 0.1 sec and a 1 sec interval between pulses produced a mean temperature rise of 0.89 +/- 0.27 degrees C at the cemento-enamel junction area and a mean temperature increase of 2.04 +/- 0.47 degrees C at the apex. A 2-W power setting with a 0.1 sec pulse duration and a 1 sec interval between pulses resulted in a mean temperature increase of 1.58 +/- 0.45 degrees C at the CEJ and a mean temperature rise of 2.59 +/- 0.20 degrees C at the apex. Based upon the results of this study, it was concluded that an argon laser operating at 1 or 2 W of power with a 0.1 sec pulse duration could be used to remove pulpal tissue without creating an excessive increase in the external temperature of the tooth.

Dentin↗
PubMed1992

Power and time requirements for use of the argon laser to polymerize composite resins.

A carefully controlled laboratory study was conducted to determine the optimum power setting and polymerization cycle time to cure four commercially available composite resins with an argon laser. Most effective resin polymerization was achieved when Prisma APH was polymerized at 310 mW for 7 seconds, when Herculite was polymerized at 160 mW for 12 seconds, when P-50 was polymerized at 525 mW for 13 seconds and when Silux Plus was polymerized at 270 mW for 13 seconds. The exact parameters of laser power and exposure time seem to be material specific, with greater variation being noted in power setting than in exposure time.

Argon↗
PubMed1991

Post polymerization strength values of an argon laser cured resin.

A hybrid composite resin, Prisma APH, and a microfilled composite resin, Silux Plus, were compared regarding diametral tensile strength values following conventional visible light polymerization and argon lasing. The time interval between resin polymerization and physical property testing ranged from 1 hour to 20 days. Results demonstrated considerable mean tensile strength value variation in the earlier phases of the study with a lessening of the differences between the tensile strengths achieved by each method of polymerization as the 20 day interval was approached. It was concluded that composite resin testing protocols should be lengthened to be able to fully assess the effects of the widely variant, time dependent mean test results.

Argon↗
PubMed1991

Application of the argon laser to dentistry.

A review was conducted to determine specific areas of application of the argon laser to dentistry. When appropriate, comparisons between the argon laser and other treatment methods were made. It was concluded that the argon laser has applicability in composite resin placement, in enamel and dentin bonding procedures, in preventive dental therapies, and in endodontic procedures.

Argon↗
PubMed1991

Degree of composite resin polymerization with visible light and argon laser.

A study was conducted to compare the degree of resin polymerization achievable using conventional visible light techniques and argon lasing. High performance liquid chromatography was used to extract unpolymerized resin from microfilled and small particle composite resin samples following photoactivation with visible light and the argon laser. It was determined that a significantly greater degree of microfilled resin polymerization was achievable following argon lasing compared to exposure to conventional visible light techniques. Although the small particle composite resin samples were polymerized as well as, or slightly better, with the argon laser, the differences were found to be insignificant. As a result, the argon laser should be considered a potentially advantageous method of initiating the polymerization of dental composite resin restorations.

Argon↗
PubMed1989

Enhancement of physical properties of resin restorative materials by laser polymerization.

A study was conducted to compare the compressive strength, diametral tensile strength, transverse flexural strength, and flexural modulus of a microfilled and a small particle composite resin restorative material following argon laser and conventional visible light polymerization techniques. All physical properties examined in this study were enhanced by laser polymerization. The diametral tensile strength of both types of restorative materials was significantly greater following laser polymerization, as were the transverse flexural strength and the flexural modulus of the microfilled resin restorative material. Additionally, these results were obtained with a laser polymerization time that was one-fourth that used for visible light activation. It was concluded that the argon laser is a potentially advantageous means of initiating the polymerization of dental composite resin restorations.

Acrylic Resins↗