Anesthetic Efficacy of the Supplemental X-tip Intraosseous Injection in Patients with Irreversible Pulpitis
John Nusstein, DDS, MS, Shawn Kennedy, DDS, MS, Al Reader, DDS, MS, Mike Beck, DDS, MA, and Joel Weaver, DDS, PhD
Direct Capping with Four Different Materials in Humans: Histological Analysis of Odontoblast ActivityAntonio Scarano, DDS, Licia Manzon, MD, DDS, Roberto Di Giorgio, MD, DDS, Giovanna Orsini, DDS, MS, Domenico Tripodi, MD, DDS, and Adriano Piattelli, MD, DDS
Pseudoramibacter alactolyticusin Primary Endodontic Infections
Jośe F. Siqueira Jr., DDS, MSc, PhD, Isabela N. Rôças, DDS, MSc
Clinical and Radiographic Evaluation of Root-canal Obturation with Obtura II
N. Tani-Ishii, DDS, PhD, and T. Teranaka, DDS, PhD
In VitroNeurotoxic Evaluationof Root-end-filling MaterialsMahshid Asrari, DDS, and Doug Lobner, PhD
Effect of MTAD on Flexural Strength and Modulus of Elasticity of DentinTanya K. Machnick, DDS, Mahmoud Torabinejad, DMD, MSD, PhD, Carlos A. Munoz, DDS, MSD, and Shahrokh Shabahang, DDS, MS, PhD
Radiopacity of Endodontic Sealers: Development of a New Method for Direct MeasurementMichael Tagger, DMD, MS, and Alexander Katz, DMD
Evaluation of an Ultrasonic Technique to Remove Fractured Rotary Nickel-Titanium Endodontic Instruments from Root Canals: An Experimental Study
Jeff R. Ward, BDS, Peter Parashos, MDSc, and Harold H. Messer, MDSc, PhD
Anesthetic Efficacy of the Supplemental X-tip Intraosseous Injection in Patients with Irreversible PulpitisJohn Nusstein, DDS, MS, Shawn Kennedy, DDS, MS, Al Reader, DDS, MS, Mike Beck, DDS, MA, and Joel Weaver, DDS, PhD
The purpose of this study was to determine the anesthetic efficacy of the supplemental intraosseous injection, using the X-tip system in an apical location, in mandibular posterior teeth diagnosed with irreversible pulpitis when the conventional inferior alveolar nerve block failed. Thirty-three emergency patients, diagnosed with irreversible pulpitis of a mandibular posterior tooth, received an inferior alveolar nerve block and had moderate-to-severe pain on endodontic access. The X-tip system was used to administer 1.8 ml of 2% lidocaine with 1:100,000 epinephrine. The X-tip injection site was 3- to- 7-mm apical to the mucogingival junction of the affected tooth. Success of the X-tip intraosseous injection was defined as none or mild pain on endodontic access or initial instrumentation. The results of this study demonstrated that 6 of 33 (18%) X-tip injections resulted in backflow of anesthetic solution into the oral cavity; none were successful in obtaining anesthesia. Twenty-seven of the remaining 33 X-tip injections (82%) were successful. We conclude that when the inferior alveolar nerve block fails to provide profound pulpal anesthesia, the X-tip system, when used in an apical location and when there was no backflow of the anesthetic solution into the oral cavity, was successful in achieving pulpal anesthesia in mandibular posterior teeth of patients presenting with irreversible pulpitis.
Direct Capping with Four Different Materials in Humans: Histological Analysis of Odontoblast ActivityAntonio Scarano, DDS, Licia Manzon, MD, DDS, Roberto Di Giorgio, MD, DDS, Giovanna Orsini, DDS, MS, Domenico Tripodi, MD, DDS, and Adriano Piattelli, MD, DDS
Pulp inflammation in restored teeth is mainly due to the presence of bacterial or bacterial products introduced by microleakage around the restoration or to the material toxicity. Recent knowledge has permitted a precise identification of the risks for pulpal irritation associated with adhesive materials and procedures. The purpose of the this work was to evaluate the cellular events that occur in direct pulp exposure capped using different materials. Twenty-four vital teeth without caries, scheduled for extraction for orthodontic reasons, were selected. After a control of the hemostasis, each pulp was directly capped with a different material. The samples were randomly divided into four groups of six specimens each: group I: dental-bonding agent (Solist) followed by resin composite (Ecusit); group II: dental adhesive (Prompt) and resin composite (Pertac II); group III: traditional calcium hydroxide (Dycal) plus resin composite (Ecusit); group IV: light-curing calcium hydroxide (Ultrablend Plus) and amalgam (Dentsply). After 15 days the teeth were extracted, immediately fixed in 10% buffered formalin, embedded in resin (7200 Technovit), and prepared for thin ground sections with Precise 1 System. In the specimens of all groups, there were active odontoblasts near the composite resins and no newly formed dentin. Small quantities of inflammatory cells were present. A 1-to-3-μm layer zone of necrosis was present. In conclusion, all materials tested in this study induced similar tissue responses.
Pseudoramibacter alactolyticusin Primary Endodontic Infections
Jośe F. Siqueira, Jr., DDS, MSc, PhD, Isabela N. Rôças, DDS, MSc
A nested polymerase chain reaction (PCR)-based method was used to directly survey samples taken from primary endodontic infections for the occurrence of Pseudoramibacter alactolyticus. Identification by nested PCR was performed in root-canal samples from teeth associated with asymptomatic periradicular lesions or acute apical periodontitis, and in pus samples from acute periradicular abscesses. DNA was extracted from the samples and initially amplified using universal 16S rDNA primers. A second round of amplification used the first PCR products to detect a specific fragment of P. alactolyticus 16S rDNA. P. alactolyticus was detected in 76% of root-canal samples from teeth showing asymptomatic periradicular lesions, in 60% of samples taken from root canals associated with acute apical periodontitis, and in 32% of pus samples aspirated from acute periradicular abscesses. No significant association of this species with clinical symptoms was observed (p > 0.01). In general, P. alactolyticus occurred in 56% of samples taken from infections of endodontic origin. The high prevalence of P. alactolyticus in infections of endodontic origin as detected by nested PCR in this study, and its apparent pathogenicity, particularly in mixed infections, indicate that this bacterial species is a candidate endodontic pathogen that can participate in the etiology of different forms of periradicular diseases.
Clinical and Radiographic Evaluation of Root-canal Obturation with Obtura II
N. Tani-Ishii, DDS, PhD, and T. Teranaka, DDS, PhD
This study evaluated clinical and radiographic healing of 236 root-canal treatments in 131 cases obturated with the Obtura II system. One operator performed all canal preparation and obturation with sealer. A standardized apical-coronal preparation technique instrumented all canals. Clinical symptoms, periodontal condition, and radiographic findings were evaluated at 3, 6, and 12 months. Radiographs taken immediately postobturation were compared to recall radiographs. The level of the final root filling was classified as short (more that 2 mm short of the apex), flush (within 2 mm), or over (beyond) in 12.7%, 81.4%, and 5.9% of cases, respectively. More than 96% of cases were treated successfully by the Obtura II system. Where roots were filled flush, over, or short, lesions healed in 97%, 93%, of cases, respectively, with no significant differences (p < 0.05). Root filling excess had no impact on the healing process.
In VitroNeurotoxic Evaluationof Root-end-filling Materials
Mahshid Asrari, DDS, and Doug Lobner, PhD
Root-end-filling materials have been tested for toxicity on several cell types, but their toxicity has not been tested on neurons. In this study we evaluated the neurotoxicity in murine cerebral cortical cell cultures of four commonly used root-end-filling materials: mineral trioxide aggregate, amalgam, Super EBA, and Diaket. Standardized amounts of each material were places on culture-well inserts, allowing the material to be exposed to the culture bathing media without causing physical disruption of the cells. Cell death was quantified by assaying release of the cytosolic enzyme lactate dehydrogenase. Exposure of cortical cultures to freshly mixed or 7-day-old MTA did not cause significant neuronal death, whereas exposure to freshly mixed or 7-day-old amalgam, Super EBA, and Diaket resulted in significant neuronal death (p < .05). Thus, each material, except for mineral trioxide aggregate, can induce neurotoxicity, even when allowed to set thoroughly.
Effect of MTAD on Flexural Strength and Modulus of Elasticity of Dentin
Tanya K. Machnick, DDS, Mahmoud Torabinejad, DMD, MSD, PhD, Carlos A. Munoz, DDS, MSD, and Shahrokh Shabahang, DDS, MS, PhD
The purpose of this study was to evaluate the effect of MTAD on the flexural strength and modulus of elasticity of dentin. Dentin bars were randomly assigned to eight groups treated with various concentrations of NaOCI (5.25%, 2.65%, 1.31%, 0.66%), 17% EDTA, MTAD, saline, or according to a clinical protocol with 1.3% NaOCI and then 5 min of MTAD. Specimens were subjected to flexural strength and modulus of elasticity tests. Two-sample t test (α = 0.05) showed no statistically significant differences between various groups except for a reduction in flexural strength for the 2-h MTAD group (p = 0.002) and the EDTA group (p = 0.002). A significant reduction of modulus of elasticity for the 2-h MTAD group (p < 0.001), EDTA group (p < 0.001), and 0.6% NaOCI (p < 0.002) also was noted. There was no significant difference in flexural strength and modulus of elasticity between the dentin bars exposed to saline or MTAD when applied according to the clinical protocol (p > 0.05). These results indicate that MTAD can be used as prescribed for clinical use without affecting the physical properties of the dentin.
Radiopacity of Endodontic Sealers: Development of a New Method for Direct MeasurementMichael Tagger, DMD, MS, and Alexander Katz, DMD
Radipacity is an essential attribute of endodontic filling materials. It is important to see clearly the root canal filling to detect its presence, extent, and apparent condensation. National and international standards require a minimal radiopacity equivalent to 3 or 4 mm of aluminum, yet some products made by reputed companies do not meet this requirement. The result may by unjustified downgrading of clinical cases. The purpose of this investigation as 2-fold: to develop a novel and easily reproducible technique for assessing the radiopacity of endodontic sealers and to apply it to measure the opacity of 21 current cements poured in 6- x 1-mm wells. As in the currently recommended technique, the standardized samples are radiographed alongside an aluminum stepwedge but instead of using an optical densitometer to measure the density and then calculate the radiopacity, the image is digitized. The gray pixel value of the test material is compared with the stepwedge, using computer software, to find the corresponding step. The opacity of the samples ranged from 1.6 mm to more than 11 mm of aluminum. The technique can be advanced to a dry, chemical-less variant by using radiation captors, as for periapical X-rays, instead of film.
Evaluation of an Ultrasonic Technique to Remove Fractured Rotary Nickel-Titanium Endodontic Instruments from Root Canals: An Experimental Study
Jeff R. Ward, BDS, Peter Parashos, MDSc, and Harold H. Messer, MDSc, PhD
The use of nickel-titanium rotary instruments in endodontic practice is increasing. One frequently mentioned problem is fracture of an instrument within the root canal. To date, there is no consistently safe and successful technique for removing these fractured instruments. This study evaluates the use of an ultrasonic technique to remove fractured rotary nickel-titanium instruments from narrow, curved canals in both simulated (resin blocks) and mesiolingual canals of extracted mandibular first molars. A technique using ultrasonic tips, combined with the creation of a “staging platform” and the use of the dental operation microscope, was consistently successful and safe at removing fractured rotary nickel-titanium instruments from curved root canals, when some part of the fractured instrument segment was located in the straight portion of the canal. When the fractured instrument segment was located entirely around the curve, the success rate was significantly decreased and major canal damage often occurred.