Biomedical subjects

F H Kahn

Publications and source records attributed to F H Kahn.

10 recordsLinked to original sources

PubMed1997

An in-vitro evaluation of sealer placement methods.

Successful root canal therapy is dependent upon obturating the root canal system. A critical component of the filling procedure is sealer placement. This in vitro study investigated the efficacy of six methods of sealer placement using clear plastic blocks with simulated curved canals instrumented to the apex using a step-back technique. After sealer placement and setting, the blocks were cross-sectioned at 2 mm intervals from mid-canal to apex. The sections were evaluated with a stereo operating microscope at x6 magnification for placement of an evenly distributed layer of sealer around the prepared canal walls. The lentulo spiral and the Max-i-Probe Delivery System were the most effective means of sealer placement, followed by ultrasonic and sonic files. The least effective methods were the paper point and the K file.

Evaluation Studies as Topic↗

PubMed1996

Comparison of fatigue for three prefabricated threaded post systems.

Post designs may have a direct effect on fracture resistance of endodontically treated teeth. This in vitro study compared the resistance of three prefabricated threaded post systems with lateral shearing forces. After endodontics were completed, prefabricated posts were inserted according to the manufacturer's instructions. A silver amalgam core was placed, and extracted human teeth were prepared to a standard size with a 1 mm gingival chamfer finished on sound dentino A cast was fabricated and cemented, and the specimens were thermocycled. The test samples were secured to an Instron testing machine and loaded until failure. Fracture patterns were recorded, fractured surface areas were measured, and compressive stresses were calculated. However, there were no statistically significant differences among threaded posts in each test group.

Cementation↗

PubMed1995

An in vitro evaluation of the irrigating characteristics of ultrasonic and subsonic handpieces and irrigating needles and probes.

The objective of this in vitro study was to evaluate the efficacy of a variety of endodontic irrigating devices. This study utilized plastic blocks with artificial canals to simulate the clinical setting. The canals were instrumented, and red food dye was introduced into each canal. The blocks were placed in a jig to simulate maxillary and mandibular arch orientation. Irrigation was performed with: (a) B-D 22-gauge needle; (b) Monoject Endodontic Needle 23 and 27 gauge; (c) Max-i-Probe 25-, 28-, and 30-gauge probes; (d) Cavi-Endo ultrasonic handpiece; and (e) Micromega 1500 subsonic handpiece. A Sony Camcorder was used to record the effect of irrigation on the simulated canal contents. Tape review enabled the investigators to observe dye clearance effected by each modality. The Max-i-Probe probes were the most effective instrument used to clear dye from the simulated canals in both the mandibular and maxillary positions.

Analysis of Variance↗

PubMed1991