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Background This study investigated the ability of different irrigation protocols to keep dentinal tubules (DT) open and avoid their blockage by the smear layer (SL) during the cleaning and shaping procedure (CSP). Methods Twenty-five extracted teeth were divided into five groups (n = 5): group 1, NaOCl was kept in the canal during instrumentation and then washed out with distilled water, and the canal was irrigated with NaOCl with EndoVac in between files; group 2, the same procedure as group 1, but NaOCl was replaced by EDTA; group 3, EDTA was kept in the canal during instrumentation and then washed out with distilled water, and the canal was irrigated with NaOCl with EndoVac in between files; group 4, the same as group 3, but NaOCl and EDTA were alternated; and group 5 (control), the procedure was the same with group 1, but NaOCl was replaced by distilled water. A scanning electron microscope was used to evaluate the cleanliness of DT at three different levels of the canals. Results Groups 3 and 4 showed better ability to keep DT open during CSP than the other groups. Group 4 only showed statistically significant better results than group 3 at middle third (P Conclusions Alternating the use of NaOCl and EDTA with water in between can keep DT open better and avoid their blockage by SL during CSP compared with the use of NaOCl or EDTA alone.

Although retrograde peri-implantitis (RPI) is not a common sequela of dental implant surgery, its prevalence has been reported in the literature to be 0.26%. Incidence of RPI is reported to increase to 7.8% when teeth adjacent to the implant site have a previous history of root canal therapy, and it is correlated with distance between implant and adjacent tooth and/or with time from endodontic treatment of adjacent tooth to implant placement. Minimum 2 mm space between implant and adjacent tooth is needed to decrease incidence of apical RPI, with minimum 4 weeks between completion of endodontic treatment and actual implant placement. The purpose of this study is to compile all available treatment modalities and to provide a decision tree as a general guide for clinicians to aid in diagnosis and treatment of RPI.Literature search was performed for articles published in English on the topic of RPI. Articles selected were case reports with study populations ranging from 1 to 32 patients. Any case report or clinical trial that attempted to treat or rescue an implant diagnosed with RPI was included.Predominant diagnostic presentation of a lesion was presence of sinus tract at buccal or facial abscess of apical portion of implant, and subsequent periapical radiographs taken demonstrated a radiolucent lesion. On the basis of case reports analyzed, RPI was diagnosed between 1 week and 4 years after implant placement. Twelve of 20 studies reported that RPI lesions were diagnosed within 6 months after implant placement. A step-by-step decision tree is provided to allow clinicians to triage and properly manage cases of RPI on the basis of recommendations and successful treatments provided in analyzed case reports. It is divided between symptomatic and asymptomatic implants and adjacent teeth with vital and necrotic pulps.Most common etiology of apical RPI is endodontic infection from neighboring teeth, which was diagnosed within 6 months after implant placement. Most common findings, radiographically and clinically, are lesions around implant apex and sinus tract. A small number of implants did not improve with treatment. Decision tree provides a path to diagnose and treat lesions to facilitate their management. Further studies are needed to focus on histologic data around periapical microbiota to establish specific etiology and differential diagnoses compared with marginal peri-implantitis and other implant-related conditions.

Objective The investigation was conducted to better characterize the clinical, radiographic, and histopathologic features of cemental tears from a review of 21 cases. Study Design This was a retrospective review of consecutive cases collected from patient records of the investigators. Results Twenty-one cases were identified during an 8-year period. Maxillary incisors were most often affected (47.6%). All lesions presented with pain. They occurred as radiolucencies along the root of a vital or endodontically treated tooth and were classified as D-shaped (38.1%), thin-vertical-line (23.8%), thick-vertical-line (14.3%), J-shaped (19.0%), or periapical radiolucencies (4.8%). All lesions showed focal destruction of the lamina dura, with 66.7% exhibiting extension into the medullary bone. Histopathologic diagnoses included intramedullary fibrous scar (28.6%) and chronic fibrosing osteomyelitis (71.4%), all associated with embedded cemental fragments. Five associated teeth were also examined: All showed tears beneath the remaining cementum. Four cases were successfully treated with curettage without tooth extraction; endodontic therapy was performed, probably mistakenly, in 8 cases. Conclusions Cemental tears produced symptomatic, localized chronic inflammation characterized usually by a vertical radiolucency adjacent to a root. These lesions may not be as rare as previously thought and extraction may not be the best treatment.

Biological complications involving dental implants include peri-implant diseases such as peri-implant mucositis and peri-implantitis. The latter presents with progressive bone loss from the alveolar crest in a coronal apical direction. However, a separate disease entity termed retrograde peri-implantitis (RPI), which presents with progressive bone loss at the periapex of the implant, also exists and may be of particular interest to endodontists because it typically presents with periapical pathology of both the implant and adjacent tooth or at a site that previously housed an endodontically treated tooth. The reported prevalence of retrograde peri-implantitis is 0.26%, which is much lower than the prevalence of marginal peri-implantitis; however, its incidence increases to 7.8% when teeth adjacent to the implant exhibit an endodontic infection. It is positively correlated with a shorter distance between the implant and the adjacent tooth and a shorter time elapsed from the endodontically treated adjacent tooth to implant placement. This case report describes a patient diagnosed with an RPI lesion (RPI) associated with an adjacent endodontically treated tooth with a persistent periapical radiolucent lesion. The diagnosis, possible etiology, and management of the RPI lesion is thoroughly reported including follow-up visits showing complete resolution after subsequent periodontal and endodontic therapy. Endodontic evaluation of teeth adjacent to the implant site should be performed for primary prevention of RPI. Proper classification of RPI will aid in determining the course of treatment; class 1 and 2 cases require endodontic therapy of the involved teeth for healing to occur.

Cells from virtually all organisms respond to a variety of stresses by the rapid synthesis of a highly conserved set of polypeptides termed heat shock proteins (HSPs). HSPs protect cells under adverse conditions such as infection, inflammation, and disease. We hypothesize that endodontic infection might result in an imbalance in the expression of heat shock genes, accounting for different clinical outcomes in periapical lesions.We analyzed the expression of 44 HSPs genes using a pathway-specific real-time polymerase chain reaction array in 93 human periapical granulomas and 24 healthy periodontal ligament tissues collected postoperatively. Observed variations in the expression of HSP genes were also analyzed based on the classification of periapical granulomas as active or inactive. In addition, U937 cells were differentiated into macrophages, infected with different concentrations of purified Escherichia coli lipopolysaccharide (LPS), and used as templates for the HSP gene array. Protein expression was assessed by immunohistochemistry.The expression of HSP genes was significantly increased in granulomas compared with healthy periodontal ligament (P.00001). Among the 44 HSP genes, DNAJC3, HSPA4, HSPA6, and HSPB1 showed the highest expression levels in both granulomas and LPS-treated macrophages. DNAJC3, HSPA6, and HSPB1 were highly expressed in active lesions, whereas HSPA4 expression was higher in inactive lesions (P.005). Higher concentrations of LPS led to increased HSP expression in macrophages (P.0001). Immunocytochemistry confirmed the expression and colocalization of HSPB1 and HSPA6 proteins in the cytoplasm of LPS-infected macrophages.The observed differential expression patterns of HSPs in periapical granulomas and LPS-infected macrophages suggest that HSP genes and proteins are involved in periapical lesion development and may account for different clinical outcomes. Understanding the role of the heat shock response might provide additional insights into the process of periapical lesion development.

Introduction The purpose of this study was to investigate the depths of penetration of a calcium silicate–based sealer in dentinal tubules by using 3 different obturation methods. Methods One hundred extracted human permanent anterior teeth were endodontically prepared and divided equally into 3 experimental groups and 1 control group as follows: CPoint single cone (CPSC), gutta-percha single cone (GPSC), gutta-percha vertical condensation (GPVC), all with a calcium silicate–based sealer and calcium indicator Fluo-3, and CPoint single cone with a calcium indicator Fluo-3 (CPF3) without sealer as the control. The roots of the teeth in each group were axially cross-sectioned, and the surfaces were examined under confocal laser scanning microscopy at ×10 and ×20 magnifications. The sealer penetration depths were measured at their maximum depths and at 4 circumferential depths (12, 3, 6, and 9 o'clock) by using fluorescence. Results Statistical analyses by using one-way analysis of variance and repeated measures analysis with linear mixed models showed no statistically significant difference among the mean maximum depth measurements (CPSC, 283.83 μm; GPSC, 318.66 μm; and GPVC, 313.03 μm; P = .7553) and among the average depths across all points (CPSC, 111.24 μm; GPSC, 135.38 μm; and GPVC, 126.62 μm; P = .5304) for the 3 experimental groups. Conclusions The pressure derived from hygroscopic expansion of CPoint or warm vertical condensation did not enhance penetration depths of the calcium silicate–based sealer. Sealer penetration into the dentinal tubules occurred independent of the obturation technique.

Objective RetroMTA® is a new hydraulic bioceramic indicated for pulp capping, perforations or root resorption repair, apexification and apical surgery. The aim of this study was to compare the radiopacity, pH variation and cytotoxicity of this material to ProRoot® MTA.Material and Methods Mixed cements were exposed to a digital x-ray along with an aluminum stepwedge for the radiopacity assay. pH values were verified after incubation period of 3, 24, 48, 72 and 168 hours. The cytotoxicity of each cement was tested on human periodontal ligament fibroblasts using a multiparametric assay. Data analysis was performed using ANOVA and Tukey’spost hoc in GraphPad Prism.Results ProRoot® MTA had higher radiopacity than RetroMTA®(p0.05) although pH levels of both materials reduced over time. Both ProRoot® MTA and RetroMTA® allowed for significantly higher cell viability when compared with the positive control (p

Statement of problem Fractures of endodontically treated teeth have been attributed to weakened tooth structure caused by root canal enlargement and post preparation. Purpose The purpose of this in vitro study was to evaluate the fracture resistance of roots filled with either gutta percha, composite resin (LuxaCore Dual), or calcium silicate-based cement (Biodentine). Material and methods One hundred twenty freshly extracted, human, permanent maxillary anterior teeth were sorted by type and assigned to 1 of 4 groups (n=30). The teeth in group NT were not endodontically treated and served as the control. The teeth in groups GP, LC, and, BD were accessed and instrumented to size 40/06. In group GP, the root canals were completely filled with gutta percha. In groups LC and BD, only the apical 5-mm portion of the root canals was filled with gutta percha, and the remaining portion of the root canals was filled with (LuxaCore Dual) in group LC and with (Biodentine) in group BD. Fracture resistance (kN) was assessed at the middle portion of each root, using a 3-point bending test with a universal testing machine exerting a compressive load on a loading pin at a crosshead speed of 0.5 mm/min until fracture occurred. One-way ANOVA was used to compare the mean root fracture resistance among the 4 groups (α=.05). Results The mean ± SD fracture loads were 2.13 ±0.53 kN for group NT, 1.97 ±0.60 kN for group GP, 2.18 ±0.71 kN for group LC, and 2.22 ±0.54 kN for group BD. No statistically significant differences were found among the 4 groups ( P >.05). Conclusions The roots of endodontically treated maxillary anterior permanent incisors filled with gutta percha, Biodentine, or LuxaCore Dual had resistance to fracture similar to that of teeth that were not endodontically treated.

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.

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.

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.

Aim To examine in vitro whether Profile or Hero 642 nickel–titanium rotary instrument systems substantially reduce the minimum canal wall thickness present following root-canal preparation. Methodology The canal anatomy of 26 mesial roots from mandibular molars with separate buccal and lingual canals was evaluated before and after instrumentation using the Endodontic Cube. Following access, working lengths were determined and then samples invested within the cube using acrylic resin. Canal cross-sections were subsequently prepared. Samples were then instrumented within the cube and pre- and post-instrumentation images of the sections were compared to determine the minimum canal wall thickness remaining after preparation. Results Buccal and lingual canals within the sections from each level (coronal to apical) showed a reduction in minimum canal wall thickness after instrumentation. No statistically significant differences in canal wall thickness were found between the two systems at any level of the root. Conclusions Instrumentation with either of the two systems under investigation did not compromise canal wall thickness. Pre-operative canal wall thickness was found to be the most significant factor determining the minimum canal wall thickness after preparation.

Introduction The implantable cardioverter defibrillator (ICD) is an electronic device that emits electrical signals to the heart via lead wires and electrodes. It is used for cardiac rhythm monitoring and treatment. Because electronic dental devices have been shown to produce electromagnetic fields, we hypothesize that they may interfere with ICD function. Methods Nine dental devices (heat carrier, electronic apex locator, electric pulp tester, unipolar electrosurgery unit, electric motor, curing light, and 3 gutta-percha guns) were tested in this study for their ability to interfere with the function of 4 ICDs (2 single-chambered and 2 dual-chambered ICDs). ICD activity was monitored for 30 seconds using an ICD programmer (Medtronic 2090; Minneapolis, MN) and evaluated through an electrogram test strip printout. Results Electromagnetic interference was detected with the electric motor, curing light, electric pulp tester, and electrosurgery unit although no electromagnetic disturbances were detected with these devices. No electromagnetic interferences were observed for the gutta-percha guns, heat carrier, and apex locator. However, the electrosurgery unit affected the dual-chambered ICD (Consulta CRT-D, Medtronic) and delivered therapies for fibrillation when no ventricular fibrillation was present. Conclusions Our results suggest that the electrosurgery unit produces electromagnetic disturbances with unwanted therapy delivery shock and potentially clinically significant outcomes.

Aim To evaluate the cytotoxic effects of triple antibiotic paste (TAP), double antibiotic paste (DAP), minocycline and calcium hydroxide and their influence on cytokine mRNA expression levels on human periodontal ligament (HPDL) fibroblasts. Methodology Triple antibiotic paste, DAP and Ca(OH)2 test samples were immersed in culture medium and incubated at 37 °C for 24 and 48 h. HPDL cells were seeded at a density of 2 × 104 cells and exposed to either culture media (negative control), 0.1% SDS (positive control), 24- or 48-h elutes of each test material and incubated for 24 h. A multiparametric cytotoxicity assay kit (XTT, NR and CVDE) was used to evaluate the cytotoxic effects of each test material. Results were analysed using an ELISA plate reader and light absorbances of 450 and 530 nm as references. Cytokine mRNA expression levels in HPDL cells treated with the materials were also investigated using real-time PCR. Expression levels were calculated using the comparative 2−ΔΔCt method. Statistical analyses included anova followed by Bonferroni correction. Results Triple antibiotic paste and minocycline were the most cytotoxic materials when compared with DAP and Ca(OH)2 in all three (XTT, NR and CVDE) assays (P 0.05) were found for cytokine gene expression levels after exposure to 24- or 48-h elutes of any of the materials except for IL6, which had significantly higher mRNA levels with the 24-h TAP elute (P

This study examined histologically the effect of three sealers used with gutta-percha as root-end fillings placed in a replantation model. A total of 14 molar teeth were used in seven monkeys. After extraction, root ends were resected, the canals contaminated with oral bacteria, root-end cavities prepared, and fillings of gutta-percha and sealer placed prior to replantation. After 8 weeks the teeth and surrounding jaw were removed and prepared for histological examination. Six roots filled with gutta-percha plus a fortified zinc oxide-eugenol cement (IRM), 13 with gutta-percha plus zinc oxide-eugenol (EP), and eight with gutta-percha plus Kloropercha, were available for examination. The tissue response to gutta-percha with either zinc oxide material was characterized by little or no inflammation of limited extent. In contrast, more severe inflammation was observed against root ends filled with gutta-percha and Kloropercha. Gutta-percha plus IRM or zinc oxide-eugenol had a much more favourable response than that to amalgam reported previously in a similar experiment.

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 extended0.1 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 extended0.5 mm. The difference in severity of inflammation for the two materials was statistically significant (p0.001). The tissue response to root end fillings of IRM in replanted teeth was less severe and less extensive than that to amalgam.

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.

A questionnaire was sent to diplomates of the American Board of Endodontics to determine changing trends in the treatment of endodontic emergencies since Dorn's 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.

Background Posts frequently are used to retain buildups. The authors examined the effects of post space preparation with Gates-Glidden drills on residual dentin thickness in distal roots of mandibular molars. Methods The authors embedded 26 root-treated mandibular molars in endodontic cubes and sectioned them perpendicularly to their long axis at 1.8-millimeter intervals. They placed Gates-Glidden drills nos. 3, 4, 5 and 6 sequentially to 5 mm short of working length in the distal canals. After using each drill size, the authors measured the dentin thickness from light microscopic images of the tooth slices. Results The authors analyzed data to detect changes resulting from canal instrumentation. They performed statistical analysis by partitioning the variability in a nested analysis of variance. Strip perforations occurred with a no. 4 Gates-Glidden drill 7.3 percent of the time and more frequently with larger drills. After endodontic treatment alone, the canal wall on the furcal side was less than 1 mm thick 82 percent of the time and less than 0.5 mm thick 17.5 percent of the time. Conclusions Dentin thickness correlates inversely to post space diameter. A no. 4 Gates-Glidden drill caused strip perforations in 7.3 percent of the canals studied, and therefore the authors recommend that Gates-Glidden drills larger than a no. 3 not be used in these roots. After endodontic treatment, the furcation-side dentin thickness was less than 1 mm in 82 percent of the teeth. Clinical Implications Post space preparation in mandibular molars carries significant risk of perforation. Post space in such teeth should be limited to the endodontically prepared canal.

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.

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.

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.

This study examined the effect of various zinc oxide materials as root-end fillings of teeth in a replantation model. A total of 35 molar teeth were used from 19 monkeys. After extraction, root ends were resected, the canals contaminated with oral bacteria, root-end cavities prepared and fillings placed prior to replantation. After 8 weeks the teeth and surrounding jaw were removed and prepared for histological examination. Twelve roots were filled with IRM plus dentine chips, and six with Cavit; the tissue response around root ends filled with these materials as assessed by inflammation was similar to that previous reported to IRM and Super EBA cement and was characterized by little or no inflammation of limited extent. In contrast, more severe inflammation was observed around root ends filled with plain zinc oxide-eugenol or Kalzinol; however, the reaction was neither as severe nor as extensive as that to amalgam root-end fillings. Giant cells were observed most often on the surface of fillings with Cavit and zinc oxide-eugenol. It is concluded that the tissue response to IRM with or without added dentine, Super EBA and Cavit was similar and mild; it was less severe than that to zinc oxide-eugenol and Kalzinol. All these materials had a much more favourable response than amalgam

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 × 250 mg), acetaminophen (2 × 250 mg), ibuprofen (2 × 250 mg), ketoprofen (2 × 250 mg), acetaminophen (2 × 250 mg) plus codeine (2 × 250 mg), penicillin (2 × 250 mg), erythromycin base (2 × 250 mg), penicillin plus ibuprofen (2 × 250 mg), methylprednisolone (2 × 250 mg) plus penicillin (2 × 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.

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.

Treatment modalities used for endodontic emergencies by diplomates of the American Board of Endodontics were evaluated. If swelling is not present, whether or not there is vital pulp tissue present, the treatment tends to consist of complete instrumentation of the root canals, keeping the instruments short of the radiographic apex; adjusting the occlusion; and prescribing analgesics. If swelling is present, treatment consists of opening the tooth, adjusting the occlusion, prescribing analgesics and antibiotics, and making an incision when the swelling is fluctuant.