Taxonomic Changes of Bacteria Associated with Endodontic Infections
José F. Siqueira Jr, DDS, MSc, PhD
Incidence of Flare-ups and Evaluation of Quality after Retreatment of Resorcinol-Formaldehyde Resin (“Russian Red Cement”) Endodontic Therapy
Tom G. Gound, DDS, MS, David Marx, PhD, and Nathan A. Schwandt, DDS
Calcium Hydroxide as an Intracanal Medication: Effect on Posttreatment Pain
Richard E.Walton, DMD, MS, Issac F. Holton, Jr., DMD, and Robert Michelich, DDS
The Significance of Needle Deflection in Success of the Inferior Alveolar Nerve Block in Patients with Irreversible Pulpitis
Shawn Kennedy, DDS, MS, Al Reader, DDS, MS, John Nusstein, DDS, MS, Mike Beck, DDS, MA, and Joel Weaver, DDS, PhD
Evaluation of Meloxicam (A Cox-2 Inhibitor) for Management of Postoperative Endodontic Pain: A Double-blind Placebo-controlled Study
Mohammad Hosein Nekoofar, DDS, MS, Marzieh Sadeghipanah, DDS, MS, and Ahmad Reza Dehpour, PhD
Long-term Survival of Root-canal-treated Teeth: A Retrospective Study Over 10 Years
Till Dammaschke, Dr med dent, Doris Steven, Dr med dent, Markus Kaup, Dr med dent, and Klaus Heinrich Reiner Ott, Prof Dr med dent
Aerotolerance of an Endodontic Pathogen
S. J. Thomas, DMD, and P. D. Eleazer, DDS, MS
Identification of Hard Tissue After Experimental Pulp Capping Using Dentin Sialoprotein (DSP) as a Marker
Wallis E. Andelin, DDS, MS, Shahrokh Shabahang, DDS, MS, PhD, Kenneth Wright, PhD, and Mahmoud Torabinejad, DMD, MSD, PhD
Histologic Analysis of the Cleaning Capacity of Mechanical Endodontic Instruments Activated by the ENDOflash System
Luiz Fernando Fariniuk, DDS, MSc, Flares Baratto-Filho, DDS, MSc, Antônio Miranda da Cruz-Filho, DDS, PhD, and Manoel Damião de Sousa-Neto, DDS, PhD
Evaluation of Cytotoxicity of MTAD Using the MTT-Tetrazolium Method
Wu Zhang, MD, Mahmoud Torabinejad, DMD, MSD, PhD, and Yiming Li, DDS, MSD, PhD
An In Vitro Evaluation of the Sealing Ability of a New Root-canal-obturation System
Brian P. Kardon, DMD, Sergio Kuttler, DDS, Patrick Hardigan, PhD, and Samuel O. Dorn, DDS
The Accuracy of the Root ZX Electronic Apex Locator Using Stainless-Steel and Nickel-Titanium Files
Anthony S. Thomas, DDS, MS, Gary R. Hartwell, DDS, MS, and Peter C. Moon, PhD, MS
Evaluation of Single-use Rotary Nickel-titanium Instruments
F. Charles Arens, DDS, Michael M. Hoen, DDS, H. Robert Steiman, DDS, PhD, MSD, and Gerald C. Dietz Jr., DDS
Scanning Electron Microscope Observations of New and Used Nickel-Titanium Rotary Files
Satish B. Alapati, William A. Brantley, Timothy A. Svec, John M. Powers, and John C. Mitchell
The Crystallization of Sodium Hypochlorite on Gutta-percha Cones After the Rapid-Sterilization Technique: An SEM Study
Rico D. Short, DMD, Samuel O. Dorn, DDS, and Sergio Kuttler, DDS
A Comparison of the Cleaning Efficacy of Short-Term Sonic and Ultrasonic Passive Irrigation and Hand Instrumentation in Molar Root Canals
Ronald A. Sabins, DDS, MS, James D. Johnson, DDS, MS, and John W. Hellstein, DDS, MS
Placement of Mineral Trioxide Aggregate Using Two Different Techniques
Anita Aminoshariae, DDS, Gary R. Hartwell, DDS, MS, and Peter C. Moon, PhD, MS
Patient Safety During Endodontic Therapy Using Current Technology: A Case Report
Gerald Fishelberg, DDS, and Dov Hook, DMD
Death from Actinomycosis
John I. Ingle, DDS, MSD
Taxonomic Changes of Bacteria Associated with Endodontic Infections
José F. Siqueira Jr, DDS, MSc, PhD
There have been major recent reorganizations among bacterial taxa as a result of phylogenetic taxonomic approaches. As a consequence, old species have been renamed and novel species have been proposed. The introduction of molecular technology for microbial identification has also allowed the detection of microbial taxa never previously found in endodontic infections. Therefore, the list of putative endodontic pathogens is frequently changing and expanding. The purpose of this review is twofold: to cover the taxonomic changes that the major putative endodontic pathogens have undergone in the recent years and to compile data from studies regarding the detection of known or novel bacterial species that had been only recently reported to occur in endodontic infections.
Incidence of Flare-ups and Evaluation of Quality after Retreatment of Resorcinol-Formaldehyde Resin (“Russian Red Cement”) Endodontic Therapy
Tom G. Gound, DDS, MS, David Marx, PhD, and Nathan A. Schwandt, DDS
The purpose of this retrospective study was to evaluate the quality of treatment and incidence of flare-ups when teeth with resorcinol-formaldehyde resin are retreated in a postgraduate endodontic clinic. Fifty-eight cases were included in this study. Obturated and unfilled canal space was measured on radiographs. Forty-eight percent of the total canal space was filled before retreatment; 90% was filled after retreatment. After retreatment, obturations were rated as optimal in 59%, improved in 33%, unchanged in 6%, and worse in 2%. Seven patients (12%) had postretreatment flare-ups. Data were statistically analyzed using the Cochran-Armitage Test for Discrete Variables. No statistical difference in the incidence of flare-ups was found in teeth that before treatment had more than half the canal space filled compared to teeth with less than half, cases with pre-existing periradicular radiolucencies compared to cases with normal periradicular appearence, symptomatic cases compared to asymptomatic cases, or cases with optimal fillings after retreatmemt compared to less than optimal cases. It was concluded that teeth with resorcinol-formaldehyde fillings might be retreated with a good prognosis for improving the radiographic quality, but a higher than normal incidence of flare-ups may occur.
Calcium Hydroxide as an Intracanal Medication: Effect on Posttreatment Pain
Richard E.Walton, DMD, MS, Issac F. Holton, Jr., DMD, and Robert Michelich, DDS
Calcium hydroxide is advocated as an intracanal medication for various purposes, including prevention of posttreatment symptoms, This study assessed whether calcium hydroxide had a pain-controlling effect at different times when compared with no intracanal medication. One hundred forty patients participated. Conditions diagnosed were pulp/periapical pathosis with or without symptoms. At least partial cleaning and shaping was completed. At random, either Ca(OH)2 plus H2O paste or a dry cotton pellet was placed in the canals of half the teeth, respectively. All teeth were temporized with Intermediate Restorative Material. Patients assessed posttreatment pain up to 48 h as none, mild, moderate, or severe. The pain levels in each test group [Ca(OH) 2 versus cotton pellet] at each time period were compared statistically with a multiple-regression analysis. There was no significant difference in posttreatment pain between the two groups at any time period or with any diagnosis or symptom. The use of calcium hydroxide as an intracanal medication was unrelated to the incidence and/or severity of posttreatment pain.
The Significance of Needle Deflection in Success of the Inferior Alveolar Nerve Block in Patients with Irreversible Pulpitis
Shawn Kennedy, DDS, MS, Al Reader, DDS, MS, John Nusstein, DDS, MS, Mike Beck, DDS, MA, and Joel Weaver, DDS, PhD
The purpose of this prospective, randomized, blinded study was to compare the anesthetic efficacy of the conventional inferior alveolar nerve block, administered with the needle bevel oriented away fromt he mandibular ramus, to the bidirectional-needle-rotation technique, administered using the computer-assisted Wand II anesthesia system, in patients diagnosed with irreversible pulpitis. Sixty-four emergency patients diagnosed with irreversible pulpitis of a mandibular posterior tooth randomly received, in a blinded manner, 2.8 ml of 2% lidocaine with 1:100,000 epinephrine using either a convetional inferior alveolar nerve block or a bidirectional-needle-rotational technique using the Wand II injection system. The conventional inferior alveolar nerve block was administered with the needle bevel oriented away from the mandibular ramus so the needle would deflect inward toward the mandibular foramen. The bidirectional-needle-rotation technique was administered by rotating the Wand handpiece assembly in a clockwise-counterclockwise movement (like an endodontic hand file) to minimize needle deflection. Endodontic access was begun 17 min after solution deposition, and all patients were required to have profound lip numbness. Success was defined as none or mild pain (VAS recordings) on endodontic access or initial instrumentation. The results of this study showed no significant differences (p > 0.05) between the success rates of the two techniques. The conventional inferior alveolar nerve block, with the needle bevel oriented away from the mandibular ramus, had a 50% success rate. The bidirectional-needle-rotation technique with the Wand II had a 56% success rate. Neither technique resulted in an acceptable rate of anesthetic success in patients with irreversible pulpitis.
Evaluation of Meloxicam (A Cox-2 Inhibitor) for Management of Postoperative Endodontic Pain: A Double-blind Placebo-controlled Study
Mohammad Hosein Nekoofar, DDS, MS, Marzieh Sadeghipanah, DDS, MS, and Ahmad Reza Dehpour, PhD
Successful management of endodontic pain represents a continuing challenge. The purpose of this randomized, double-blind, placebo-controlled, parallel-group trial was to compare the pain reducing effect of oral preparations of meloxicam, piroxicam, and placebo in endodontic emergency patients. A total of 51 patients who presented to the TehranUniversityendodontic clinic and one private dental clinic were invited to participate. Patients were asked to evaluate their pretreatment pain with a visual-analog scale. After root canal therapy they were randomly assigned to one of three groups: meloxicam, piroxicam, or placebo. Each patient was sent home with a visual-analog scale to fill out at 8 and 24 h after completion of therapy. The results of this study showed no significant differences between efficacy of meloxicam, piroxicam, and placebo, but a significant effect of the time factor in reducing postoperative pain in all treatment groups was observed.
Long-term Survival of Root-canal-treated Teeth: A Retrospective Study Over 10 Years
Till Dammaschke, Dr med dent, Doris Steven, Dr med dent, Markus Kaup, Dr med dent, and Klaus Heinrich Reiner Ott, Prof Dr med dent
In this retrospective study the survival rate of 190 root-canal-treated teeth of 144 patients after 10-yr minimum was evaluated. Students during their training in 1987 and 1988 had performed the treatments. Age, gender, jaw, or quantity or root canals had no influence to the success of a root-canal treatment. Teeth with an apical lesion before the endodontic treatment showed a significantly shorter likelihood of survival. The best results could be found in root canal fillings ending 0 to 1 mm and 1 to 2 mm before the apex. Comparing types of restoration, prosthetic-treated teeth with retention post and crown seem to be favorable. The study showed that root-canal treatment even conducted by students has a survival rate of 85.1% (Kaplan-Meier) after 10 yr and is a long-lasting, conservative therapy.
Aerotolerance of an Endodontic Pathogen
S. J. Thomas, DMD, and P. D. Eleazer, DDS, MS
The purpose of this study was to determine the length of time it takes to kill obligate anaerobic bacteria in a root canal exposed to room air or 3% hydrogen peroxide. Twenty-five extracted, human, permanent teeth with single canals were used. All teeth were contaminated with the anaerobe, Porphyromonas endodontalis (ATCC #35406), and were divided into five groups of five teeth each. Group 1 was exposed to 5 min of atmospheric air. Group II was exposed to 3% hydrogen peroxide for 5 min. Group III was exposed to 45 min of atmospheric air. Group IV was exposed to 3% hydrogen peroxide for 45 min. Group V, the control teeth, never left the anaerobic gas chamber. The results showed that atmospheric air exposure for up to 45 min is inadequate for eliminating P. endodontalis. The groups that were exposed to hydrogen peroxide showed no growth of bacteria.
Identification of Hard Tissue After Experimental Pulp Capping Using Dentin Sialoprotein (DSP) as a Marker
Wallis E. Andelin, DDS, MS, Shahrokh Shabahang, DDS, MS, PhD, Kenneth Wright, PhD, and Mahmoud Torabinejad, DMD, MSD, PhD
The purpose of this study was to identify the hard tissue formed early in experimental pulp exposures capped with mineral trioxide aggregate (MTA) or bone morphogenetic protein (BMP)-7 using dentin sialoprotein (DSP) as a marker. The pulps of 35 maxillary first, second, and third molar teeth from 10 male rats were experimentally exposed. The pulps were capped with MTA alone as a pulp-capping agent and final restoration or with BMP-7 followed by restoration with MTA. Five teeth with class 1 occlusal preparations, no exposure, and no restoration served as positive controls. Five teeth that received pulp exposures and no restoration served as negative controls. Five untreated third molars served as additional controls. The animals were killed at 2 weeks. The specimens were prepared and evaluated histologically and with immunohistochemistry using polyclonal antibodies raised against rat DSP. Pulps capped with MTA formed hard tissue that demonstrated significantly more immunostaining for DSP compared with BMP-7 (p = 0.0031). MTA-capped pulps also showed significantly more complete bridge formation compared with BMP-7 (p = 0.0008). Pulps capped with BMP-7 demonstrated a hard tissue that was bone-like in appearance and devoid of DSP staining.
Histologic Analysis of the Cleaning Capacity of Mechanical Endodontic Instruments Activated by the ENDOflash System
Luiz Fernando Fariniuk, DDS, MSc, Flares Baratto-Filho, DDS, MSc, Antônio Miranda da Cruz-Filho, DDS, PhD, and Manoel Damião de Sousa-Neto, DDS, PhD
The cleaning capacity of mechanical endodontic instruments activated by the ENDOflash system was evaluated by means of histologic and morphometric analyses. Tweny-two distobuccal roots of human maxillary molars from laboratory stock were randomly separated into four groups. Group 1 was instrumented with ENDOflash files, group 2 with ProFile taper .04 files, group 3 received instrumentation with Pow-R taper .04 files, and group 4 (positive control) was instrumented with Nitiflex files. After instrumentation, teeth were sectioned transversally and processed for microscopic evaluation to determine the amount of debris on root canal walls. Results obtained by morphometric analysis indicated significant statistical differences (p < 0.01) between groups. ProFile taper .04 files were significantly more efficient in cleaning the root canal, followed by Pow-R files, Nitiflex, and ENDOflash, which had the lowest levels for cleaning the root canals.
Evaluation of Cytotoxicity of MTAD Using the MTT-Tetrazolium Method
Wu Zhang, MD, Mahmoud Torabinejad, DMD, MSD, PhD, and Yiming Li, DDS, MSD, PhD
Previous studies have shown that MTAD (a mixture of a tetracycline isomer, an acid, and a detergent) is an effective antibacterial irrigant as a final rinse to remove the smear layer from the instrumented surface of root canals. In this investigation we examined the cytotoxicity of MTAD compared with that of commonly used irrigants and medications. L929 fibroblasts were grown on cell culture plates and were placed in contact with various concentrations of test irrigants and medications. The cytotoxicity of these materials was evaluated 24 h after incubation using MTT assay. Means and standard deviations of absorbance were calculated for each group and statistically analyzed to determine presence or absence of significant difference between the means. The 50% inhibitory dose values were calculated, ranked, and statistically analyzed using the sign interval for median. Based on our results it seems that MTAD is less cytotoxic than eugenol, 3% H2O2, Ca (OH)2 paste, 5.25% NaOCI, Peridex, and EDTA and more cytotoxic than 2.63%, 1.31%, and 0.66% NaOCI.
An In Vitro Evaluation of the Sealing Ability of a New Root-canal-obturation System
Brian P. Kardon, DMD, Sergio Kuttler, DDS, Patrick Hardigan, PhD, and Samuel O. Dorn, DDS
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°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.
The Accuracy of the Root ZX Electronic Apex Locator Using Stainless-Steel and Nickel-Titanium Files
Anthony S. Thomas, DDS, MS, Gary R. Hartwell, DDS, MS, and Peter C. Moon, PhD, MS
Numerous apex locator studies have been performed. Generally, they use only stainless-steel hand files for testing purposes. Today many clinicians use both stainless-steel and nickel-titanium files diring the treatment of a case. Given the widespread use of nickel-titanium files, a comparison of the accuracy in determining length with an apex locator using stainless-steel and nickel-titanium files seems clinically relevant. Campbell et al. (1) published a study where only nickel-titanium files were used. A literature search failed to reveal any studies that directly compared stainless-steel and nickel-titanium files when used with an apex locator to determine length measurements in the same tooth. The purpose of this study was to determine if there is a measurable difference in accuracy of length determination when stainless-steel and nickel-titanium files were used for this purpose in the same tooth.
Evaluation of Single-use Rotary Nickel-titanium Instruments
F. Charles Arens, DDS, Michael M. Hoen, DDS, H. Robert Steiman, DDS, PhD, MSD, and Gerald C. Dietz, Jr., DDS
The purpose of this study was to analyze the number and types of defects observed in single-use, rotary nickel-titanium instruments. Every ProFile Series 29.04 taper nickel-titanium instrument used during a 4-week period in an endodontic specialty practice was collected. All instruments were new and were used by experienced clinicians during a single patient visit. The instruments were routinely used in a crown-down manner with RC Prep lubrication and copious irrigation. The instruments were used in a MicroMega 324 air motor in a 6:1 gear reduction contra-angle at 333 rpm. The instruments were collected, ultrasonically cleaned, sterilized, and inspected at x16 magnification. Torsional, flexural, and fracture defects were recorded and statistical analysis was performed using the Kruskal-Wallis one-way analysis of variance. A total of 786 ProFile Series 29 nickel-titanium rotary instruments were evaluated; 115 (14.63%) showed some type of defect after one clinical use. Size 3 instruments had the highest defect rate (22.66%) followed by size 5 (17.30%), size 2 (17.24%), and size 4 instruments (16.10%). However, there was no statistically significant difference. The size 6 and size 7 instruments showed minimal defects (2.38% and 4.76%, respectfully). Seven of 786 files had fractured (0.891%). There was no statistically significant difference in the type of failure seen within each file size. This study does show that defects can occur even with new files in the hands of experienced endodontists, and for absolute safety a single-use approach should be followed.
Scanning Electron Microscope Observations of New and Used Nickel-Titanium Rotary Files
Satish B. Alapati, William A. Brantley, Timothy A. Svec, John M. Powers, and John C. Mitchell
The appearances of the tip sections of ProFile 0.04 taper and Lightspeed 25-mm long, ISO size 25, nickel-titanium rotary instruments were compared with a scanning electron microscope in the as-received condition and after one, three, and six stimulated clinical uses to prepare mesial canals of extracted mandibular molars. For the used ProFile instruments, there was some flattening of the characteristic material rollover and minor apparent wear at the edges of the flutes, but there was little change in the tip regions of the used Lightspeed instruments. Deposits on the surfaces of the instruments were attributed to the manufacturing processes and the in vitro preparation of root canals in the extracted teeth. The simulated clinical use did not cause substantial changes in the regions of these two brands of rotary instruments that are involved in the clinical preparation of root canals.
The Crystallization of Sodium Hypochlorite on Gutta-percha Cones After the Rapid-Sterilization Technique: An SEM Study
Rico D. Short, DMD, Samuel O. Dorn, DDS, and Sergio Kuttler, DDS
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 has 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.
A Comparison of the Cleaning Efficacy of Short-Term Sonic and Ultrasonic Passive Irrigation and Hand Instrumentation in Molar Root Canals
Ronald A. Sabins, DDS, MS, James D. Johnson, DDS, MS, and John W. Hellstein, DDS, MS
A total of 100 maxillary molar canals were hand instrumented to a master apical file size #35 and flared to a size #60 file. The canals were randomly divided into 5 groups of 20 each. Group 1 received no further treatment. Groups 2 and 3 received passive sonic irrigation for 30 and 60 s, respectively. Groups 4 and 5 received passive ultrasonic irrigation for 30 and 60 s, respectively. The roots were split longitudinally and photographed with a digital camera. The apical portion of the root was magnified to 100x. A debris score was calculated for the apical 3 and 6 mm. The debris score was calculated as a percentage of the total area of the canal that contained debris as determined by pixels in Adobe Photoshop 5.0. Passive sonic or ultrasonic irrigation, for as little as 30 s, resulted in significantly cleaner canals than hand filing alone. Ultrasonic passive irrigation produced significantly cleaner canals than passive sonic irrigation, when sonic and ultrasonic passive irrigation were compared with only each other.
Placement of Mineral Trioxide Aggregate Using Two Different Techniques
Anita Aminoshariae, DDS, Gary R. Hartwell, DDS, MS, and Peter C. Moon, PhD, MS
The purpose of this study was to determine if the adaption of mineral trioxide aggregate (MTA) would differ when placed into simulated root canals of varying length when using two different placement and condensation methods. Hand condensation was compared to ultrasonic condensation. Eighty polyethylene tubes were divided into four groups of 20 tubes each. The tubes in the four groups were prepared to receive 3-, 5-, 7-, and 10-mm lengths of MTA respectively. Each group of 20 tubes was subdivided; 10 samples of each length had MTA placed and condensed by the hand method and the other 10 by the ultrasonic method. After condensation the samples were evaluated with a light microscope and radiographs for the degree of adaptation of the MTA to the tube walls and for the presence of voids within the MTA material itself. The results demonstrated an 80% agreement for findings between the light microscopy and radiographic evaluation. Hand condensation resulted in better adaptation to the tube walls and less voids than the ultrasonic method. There was no significant difference in the results for any of the four lengths of MTA placed by the hand method (p . 0.9.). At this time hand condensation should be considered the preferred method for placement of MTA.
Patient Safety During Endodontic Therapy Using Current Technology: A Case Report
Gerald Fishelberg, DDS, and Dov Hook, DMD
It is an accepted safety practice to take precautions during endodontic treatment to prevent aspiration or swallowing of instruments (1). The placement of a rubber dam is considered the standard of care (2, 3). With the advent of new endodontic devices, new safety challenges have arisen and must be considered in addition to the placement of a rubber dam. A case report is presented that emphasizes the importance of patient safety and suggests precautions to prevent any safety-related mishaps during treatment.
Death from Actinomycosis
John I. Ingle, DDS, MSD
Death from actinomycosis, although unusual today, was devastating at one time. Although commonplace today, using antibiotics to save patients from death was unusual when penicillin was first introduced over 50 years ago.