Samuel O. Dorn

Retrograde filling materials: A retrospective success-failure study of amalgam, EBA, and IRM

A retrospective study was done to compare the success rates of teeth with three different root end filling materials. The materials studied were SuperEBA, IRM, and zinc-free high-copper spherical amalgam. Radiographs of 488 cases from two geographically distinct offices were used, with the recall period ranging from a minimum of 6 months to a maximum of 10 yr. The cases in each office were examined independently using the same criteria. The results revealed that both SuperEBA and IRM demonstrated statistically significant improvements in success rates when compared with amalgam. The success rates were 75% for amalgam, 91% for IRM, and 95% for SuperEBA. The difference between IRM and SuperEBA was not statistically significant.

Efficacy of biomechanical instrumentation: a scanning electron microscopic study

Twenty-five freshly extracted teeth were mechanically instrumented three sizes beyond the criterion of the appearance of clean, white filings. Scanning electron microscopic examination showed many irregularities as well as tissue left in the root canal system. No difference in the degree of cleanliness was observed when comparing K-type and Hedstroem files.

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.

Treatment of the endodontic emergency: A decade later

A questionnaire was sent to diplomates of the American Board of Endodontics to determine changing trends in the treatment of endodontic emergencies since Dorns survey 10 yr ago. There is a definitely greater trend toward complete instrumentation of the root canals to the apex regardless of the emergency condition than there was a decade ago. The number of respondents who leave teeth open when the pulp is nonvital has dropped dramatically in the past decade. When there is no periapical involvement, over one third of the respondents are completing treatment in one visit. A decrease in the use of classic phenolic medicaments was noted with a corresponding increase in calcium hydroxide or no medication at all.

Effectiveness of various medications on postoperative pain following root canal obturation

This prospective study compared the effectiveness of nine medications and a placebo in controlling pain following obturation. A total of 588 patients who required root canal obturation were included. After obturation of root canals, each patient took one of the medications, salicylic acid (2 x 250 mg), acetaminophen (2 x 250 mg), ibuprofen (2 x 250 mg), ketoprofen (2 x 250 mg), acetaminophen (2 x 250 mg) plus codeine (2 x 250 mg), penicillin (2 x 250 mg), erythromycin base (2 x 250 mg), penicillin plus ibuprofen (2 x 250 mg), methylprednisolone (2 x 250 mg) plus penicillin (2 x 250 mg), or a placebo, every 6 h for 72 h. All medications were encapsulated in identical capsules. The patients registered their degree of discomfort on a visual analogue scale of 0 to 9. Statistical analysis of the data showed that the incidence of postoperative pain after obturation is lower than that following complete cleaning and shaping (5.83% versus 21.76%). In addition, there was no significant difference between the effectiveness of the various medications and placebo tablets in controlling postoperative pain following obturation.

Effect of super-EBA as a root end filling on healing after replantation

The effect of Super-EBA cement as a root-end filling placed in teeth before replantation was examined in eight molar roots in monkeys. After extraction, root ends were resected, the canals contaminated with oral bacteria, root-end cavities prepared, and fillings of Super-EBA placed before replantation. After 8 wk, the jaws were removed and prepared for histological examination. The tissue response to Super-EBA was very mild, with only a few inflammatory cells being observed at the root end of 3 of the 8 roots filled. Previous work showed a similarly mild response to Intermediate Restorative Material and a very much more severe response to amalgam. It is concluded that the tissue response to Super-EBA as a root-end filling is acceptable and considerably more favorable than that to amalgam.

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.

Effect of IRM root end fillings on healing after replantation

The effect of IRM as a root end filling placed in teeth prior to replantation was examined in 21 molar teeth in monkeys. After extraction, root ends were resected, the canals contaminated with oral bacteria, root end cavities prepared, and fillings of IRM or amalgam placed prior to replantation. After 8 wk the jaws were removed and prepared for histological examination. Bacteria were demonstrated in only 9 of 15 teeth filled with IRM; 18 of the roots (60%) were associated with inflammation, which was only moderate or severe around 5 (17%), and extended > 0.1 mm around only 2 roots. In contrast, of the 6 teeth filled with amalgam, all contained bacteria in the root canals and 11 roots were associated with moderate or severe inflammation, which around 8 roots extended > 0.5 mm. The difference in severity of inflammation for the two materials was statistically significant (p < 0.001). The tissue response to root end fillings of IRM in replanted teeth was less severe and less extensive than that to amalgam.

The endodontic cube: a system designed for evaluation of root canal anatomy and canal preparation.

An extensively redesigned muffle system is presented incorporating improved design features, such as rigid external fixation and machined internal indexing to enable a more accurate, clinically relevant, and reproducible evaluation of root canal anatomy before and after preparation. Given the ability to directly observe and quantify changes in the root canal system, the information obtained using this design is comprehensive. In each tooth pretreatment evaluation provides the ideal control, reinforcing the suitability of this technique.

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.