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Biomedical subjects

Samuel O Dorn

Publications and source records attributed to Samuel O Dorn.

12 recordsLinked to original sources

The properties of Endocal 10 and its potential impact on the structural integrity of the root.

The purpose of this research was to determine if the use of Endocal 10 (previously called Biocalex 6.9) is associated with root fracture and to assess its sealability. Thirty-six freshly extracted, single canal human mandibular incisors were instrumented and randomly divided into two equal groups (n = 15). Canals in group A were obturated with vertically compacted gutta-percha and Sealapex, and those in group B were filled with Endocal 10 placed with a #25 Lentulo spiral per manufacturer's instructions. Two blinded investigators evaluated the teeth for fractures using transillumination and an operating microscope at 12 x magnification. Three of the fifteen samples filled with Endocal 10 had vertically fractured in half, whereas none of the teeth filled with gutta-percha had any evident fracture lines. The remaining teeth were tested for leakage via a fluid filtration model at 1 wk and 30 days postobturation. No leakage was found among any of the samples whether filled with gutta-percha or with Endocal 10 at either time interval. Statistical analyses were completed using Fisher's exact test (p = 0.023), which showed that there was a significant increase in chance of fracture when using Endocal 10 versus gutta-percha. The results indicate that, although Endocal 10 is able to seal the tooth as well as gutta-percha and sealer, there is a significant potential risk of root fracture.

Calcium Compounds↗

An in vitro evaluation of the sealing ability of a new root-canal-obturation system.

In this study the sealing ability of a new urethane methacrylate resin-based sealer, EndoRez, was evaluated using a fluid-filtration model. Sixty-four single-rooted lower bicuspids were decoronated, instrumented, and divided into 3 groups of 20 each with 4 teeth used as controls. In group A, the roots were obturated with EndoRez and a single cone of gutta-percha, group B with AH Plus and a single cone of gutta-percha, and group C was obturated using gutta-percha with warm vertical compaction and AH Plus sealer. All specimens were allowed to set for 7 days in 100% humidity at 37 degrees C. The groups were compared for differences in the amount of leakage (mm/h) using a Chi-square test. The leakage of group A was significantly higher at p = 0.01 than the other two groups. There was no significant difference in leakage between groups B and C.

Bicuspid↗

The crystallization of sodium hypochlorite on gutta-percha cones after the rapid-sterilization technique: an SEM study.

The purpose of this study was to identify the presence, crystallization, and subsequent removal of sodium hypochlorite crystals on gutta-percha cones after rapid sterilization. Seventy-two, fresh, standardized, gutta-percha cones were randomly selected. Each cone was observed under the scanning electron microscope and the elemental analysis machine before and after rapid sterilization using 5.25% and 2.5% sodium hypochlorite. Gutta-percha cones were rinsed after sterilization with 96% ethyl alcohol, 70% isopropyl alcohol, and distilled water independently to determine which of these agents removed the sodium-chloride crystals. There were no crystals present on the gutta-percha cones directly from the box. All gutta-percha cones had sodium-chloride crystals present after the rapid-sterilization technique using 5.25% and 2.5% sodium hypochlorite. However, the sodium-chloride crystals were removed by 96% ethyl alcohol, 70% isopropyl alcohol, and distilled water.

Alcohols↗

Effect of electronic apex locators on cardiac pacemaker function.

The purpose of this study was to assess the effects of five electronic apex locators on pacemaker function in vitro. A Biotronik Actros DR+ pacemaker was evaluated at maximum sensitivity on a flat bench top. The pacemaker lead, electronic apex locator, and oscilloscope were connected across a 150-ohm resistor. Pace monitoring was carried out with a Biotronik EPR 1000 programmer and a Tektronix TDS 220 2-channel digital real-time oscilloscope. Four of five electronic apex locators tested did not cause inhibition or interfere with normal pacemaker function. It seems that electronic apex locators can be used safely in patients with pacemakers.

Dental Instruments↗