Scott B. McClanahan

Challenges in regenerative endodontics: a case series.

INTRODUCTION An immature tooth with pulpal necrosis and apical periodontitis presents a unique challenge to the endodontist. Endodontic treatment options consist of apexification, apical barriers, or more recently, revascularization. The purpose of this case series is to report three cases that used revascularization protocol as described by Banchs and Trope. Each case presented its own special circumstances and challenges. The lessons learned from each case provided guidance for more predictable outcomes on subsequent cases. METHODS Six immature teeth with apical periodontitis (in three patients) were treated via the revascularization protocol using irrigants, a triple antibiotic paste, and a coronal seal of mineral trioxide aggregate and composite. RESULTS For follow-up, all six teeth showed resolution of periapical radiolucencies, whereas three of six teeth showed continued root development. Two teeth displayed a positive response to vitality testing. CONCLUSIONS Results from this case series show that revascularization is a technically challenging but effective treatment modality for the immature tooth with apical periodontitis. Based on this case series, the following recommendations are made to help with the revascularization technique: (1) clinicians should consider the use of an anesthetic without a vasoconstrictor when trying to induce bleeding, (2) a collagen matrix is useful for the controlled placement of MTA to a desired and optimal level, (3) patients/parents should be informed about the potential for staining, especially in anterior teeth when the paste contains minocycline, and (4) patient/parent compliance with the necessary multiple appointment treatment plan may be significant for case selection.

The Effect of Passive Ultrasonic Activation of 2% Chlorhexidine or 5.25% Sodium Hypochlorite Irrigant on Residual Antimicrobial Activity in Root Canals

Ninety-four single-canal roots were prepared using the step-down technique. Forty-two canals were irrigated with 2% chlorhexidine, 42 canals with 5.25% sodium hypochlorite (NaOCl), and 10 control canals with phosphate-buffered saline (PBS). The chlorhexidine and NaOCl groups were each then equally divided into a final irrigation group and a 1-min passive ultrasonic irrigation group. Canals were enlarged with a Parapost drill. The apical 3-5 mm was covered with nail polish. Canals were rinsed with PBS, dried, refilled with PBS, and stored. At 6 h, 20 microl of fluid was pipetted from each canal and placed into wells on agar plates, which were inoculated with Streptococcus sanguinis. The plates were incubated, and zones of inhibition were measured. Sampling was repeated at 24, 48, 72, 96, 120, 144, and 168 h. Residual antimicrobial activity with 2% chlorhexidine was statistically significantly superior to 5.25% NaOCl with irrigation alone and with final passive ultrasonic activation (p < 0.001). Chlorhexidine experimental groups demonstrated residual antimicrobial activity for as long as 168 h.

Intraorifice sealing of gutta-percha obturated root canals to prevent coronal microleakage

A study was conducted to evaluate Cavit, Intermediate Restorative Material, and Super-EBA as intraorifice filling materials to prevent coronal microleakage. Root canal instrumentation and obturation was done on 74 extracted single-rooted teeth. Three and one-half millimeters of the gutta-percha was removed from the coronal aspect of the root canal and replaced with one of the three filling materials. The teeth were suspended in scintillation vials containing trypticase soy broth, and human saliva was added to the pulp chambers. Microbial penetration was detected as an increase in turbidity of the broth corresponding to bacterial growth. At the end of 90 days, the results showed that 15% of the Cavit-filled orifices leaked, whereas 35% of the Intermediate Restorative Material and Super-EBA-filled orifices leaked. The gutta-percha obturated root canals that received an intraorifice filling material leaked significantly less than the obturated, unsealed control group--all of which leaked in < 49 days.

Evaluation of Pretreatment Analgesia and Endodontic Treatment for Postoperative Endodontic Pain

This study compares single-dose ibuprofen pretreatment for postoperative endodontic pain. Thirty-nine emergent patients were randomly assigned to 3 groups: placebo, ibuprofen tablets, or ibuprofen liquigels. Patients recorded their pain levels before and at the end of treatment, then every 6 hours for 24 hours after administration of the medications and standard endodontic treatment. Pain evaluations by using 3 pain scales (visual analog scale [VAS], category, and Heft-Parker) were highly correlated, suggesting the rationale for only using one pain scale in pain studies. No significant differences in postoperative pain levels were found between either single-dose ibuprofen formulation or the placebo control group (P = .84). Patients treated with calcium hydroxide versus obturation did not differ in postoperative pain levels (P = .44). This study suggests that single-dose pretreatment analgesia alone in endodontic pain patients will not significantly reduce postoperative pain below the reduction in pain from endodontic treatment.

Identify and Determine the Metrics, Hierarchy, and Predictive Value of All the Parameters and/or Methods Used During Endodontic Diagnosis

A Consensus Conference on Terminology was convened by the American Association of Endodontists in Chicago on Oct 3, 2008 to review solicited papers on focused questions. This paper addressed the question: Identify and determine the metrics, hierarchy, and predictive value of all the parameters and/or methods used during endodontic diagnosis. The best available clinical evidence was used to determine the sensitivity, specificity, and predictive value of pulpal and periapical testing methods and imaging technologies. Diagnosis of dental pulp diseases suffers from operators inability to test/image that tissue directly due to its location within dentin. In general, current pulp tests are more valid in determining teeth that are free of disease, but less effective in identifying teeth with pulp disease. Radiographic imaging is probably the most commonly used diagnostic tool to determine the status of root-supporting tissue, although interpretation of structural changes in the periradicular tissues is still considered unreliable.

Comparison of human polymorphonuclear neutrophil elastase, polymorphonuclear neutrophil cathepsin-G, and α2-macroglobulin levels in healthy and inflamed dental pulps

Polymorphonuclear neutrophils (PMNs) are found in dental pulp secondary to carious exposures, periodontal disease, or trauma. Lysosomal degranulation of these cells liberates cellular proteases, including elastase (PMN-E) and cathepsin-G (PMN-CG), which produce connective tissue degradation. However, nonspecific pulpal tissue destruction can be modified by a naturally occurring serum protease inhibitor alpha 2-macroglobulin (A2-M). This study relates the concentrations of human PMN-E, PMN-CG, and A2-M in healthy and inflamed pulpal samples. Evaluation of 21 specimens yielded statistically significant differences between healthy and moderate to severely inflamed pulps for all groups (p < 0.05). No significant correlation was detected among human PMN-E, PMN-CG, and A2-M in the healthy tissues (P > 0.05). However, in the moderate to severely inflamed pulps, there was a significant correlation between PMN-CG and A2-M (p < 0.05).

Natural modifiers of the inflammatory process in the human dental pulp

Concentrations of the protease inhibitors alpha 1-antitrypsin and alpha 2-macroglobulin were determined in normal and inflamed human dental pulps. Carious pulpal exposure which is associated with polymorphonuclear leukocyte infiltration and release of lysosomal enzymes was chosen as the point of verifiable inflammatory activity in the pulp. Normal samples were collected from nondiseased third molar teeth treatment planned for extraction and inflamed human pulps were collected from teeth with deep carious lesions. One half of each sample was assayed for concentration of protease inhibitors by enzyme-linked immunosorbent assay and the remaining half was examined histologically to verify the clinical diagnosis and categorize the extent of the inflammatory process. alpha 1-Antitrypsin and alpha 2-macroglobulin were detected in normal and inflamed human dental pulps in the nanogram per milliliter range. Statistically significant differences were found in the concentrations of alpha 2-macroglobulin (p less than 0.01) in moderate to severe inflammation versus normal pulp categories and between mildly inflamed pulps and moderate to severely inflamed pulps (p less than 0.05). Although differences in concentrations of alpha 1-antitrypsin were seen between inflamed and normal pulps, the differences were not statistically significant. The presence of these two protease inhibitors in the human dental pulp tissue and the increase in their concentration in acute inflammation indicates that these proteins play a role in the pathogenesis of pulpal inflammatory disease.

Frequency of Localization of the Painful Tooth by Patients Presenting for an Endodontic Emergency

INTRODUCTION Endodontic pain patients sometimes have difficulty in accurately identifying the painful tooth. We determined the frequency in which patients presenting with endodontic pain can correctly localize the painful tooth and the effect of periradicular symptoms. METHODS The frequency of localization of the painful tooth in 79 endodontic emergency patients was assessed by using patient and dentist assessment of presenting pain along with the verbal numeric rating scale (VNRS). RESULTS The results show that patients presenting with odontogenic pain can localize the painful tooth 73.3% of the time. Patients experiencing periradicular pain can localize the painful tooth (89%) significantly more often than patients with pain without periradicular symptoms (30%, p < 0.0001). CONCLUSIONS The presence of periradicular pain increases the accuracy of pain localization. The VNRS is highly correlated with other pain scales and is an acceptable initial pain-assessment tool for endodontic emergency patients.

Mandibular First Molar with Six Separate Canals

INTRODUCTION Many anatomical variations can occur within the mandibular first molar. Commonly, 3-4 canals are located, but as many as 6-7 canals have been reported. METHODS This report describes a case of a mandibular first molar with 6 separate canals (3 mesial and 3 distal) that was instrumented with conventional hand and rotary files and obturated by using a hybrid warm vertical compaction technique. RESULTS Recall examination as far as 3 years post-treatment found no sensitivity to percussion or palpation and recall radiographs after treatment show resolution of the previous apical periodontitis. CONCLUSIONS The existence of such teeth as these underlies the importance of looking for additional canals.

A titration model for evaluating calcium hydroxide removal techniques

Objective Calcium hydroxide (Ca(OH)2) has been used in endodontics as an intracanal medicament due to its antimicrobial effects and its ability to inactivate bacterial endotoxin. The inability to totally remove this intracanal medicament from the root canal system, however, may interfere with the setting of eugenol-based sealers or inhibit bonding of resin to dentin, thus presenting clinical challenges with endodontic treatment. This study used a chemical titration method to measure residual Ca(OH)2 left after different endodontic irrigation methods. Material and Methods Eighty-six human canine roots were prepared for obturation. Thirty teeth were filled with known but different amounts of Ca(OH)2 for 7 days, which were dissolved out and titrated to quantitate the residual Ca(OH)2 recovered from each root to produce a standard curve. Forty-eight of the remaining teeth were filled with equal amounts of Ca(OH)2 followed by gross Ca(OH)2 removal using hand files and randomized treatment of either: 1) Syringe irrigation; 2) Syringe irrigation with use of an apical file; 3) Syringe irrigation with added 30 s of passive ultrasonic irrigation (PUI), or 4) Syringe irrigation with apical file and PUI (n=12/group). Residual Ca(OH)2 was dissolved with glycerin and titrated to measure residual Ca(OH)2 left in the root. Results No method completely removed all residual Ca(OH)2. The addition of 30 s PUI with or without apical file use removed Ca(OH)2 significantly better than irrigation alone. Conclusions This technique allowed quantification of residual Ca(OH)2. The use of PUI (with or without apical file) resulted in significantly lower Ca(OH)2 residue compared to irrigation alone.