Influence of photobiomodulation therapy on root development of rat molars with open apex and pulp necrosis.

This study aimed to evaluate the role of photobiomodulation (PBM) in apexification and apexogenesis of necrotic rat molars with an open apex. Rat molars were exposed to the oral environment for 3 weeks. Canals were rinsed with 2.5% NaOCl and 17% EDTA, filled with antibiotic paste and sealed. After 7 days, canals were rinsed and divided into six groups (n=6): mineral trioxide aggregate (MTA); blood clot (BC); human dental pulp stem cells (hDPSC); MTA+PBM; BC+PBM; and hDPSC+PBM. In hDPSC groups, a 1% agarose gel scaffold was used. Two groups were not exposed: healthy tooth+PBM (n = 6), healthy tooth (n = 3); and one was exposed throughout the experiment: necrotic tooth (n = 3). In PBM groups, irradiation was performed with aluminum gallium indium phosphide (InGaAlP) diode laser for 30 days within 24-h intervals. After that, the specimens were processed for histological and immunohistochemical analyses. Necrotic tooth showed greater neutrophil infiltrate (p < 0.05). Necrotic tooth, healthy tooth, and healthy tooth+PBM groups showed absence of a thin layer of fibrous condensation in the periapical area. All the other groups stimulated the formation of a thicker layer of fibers (p < 0.05). All groups formed more mineralized tissue than necrotic tooth (p < 0.05). PBM associated with MTA, BC, or hDPSC formed more mineralized tissue (p < 0.05). MTA+PBM induced apexification (p < 0.05). Rabbit polyclonal anti-bone sialoprotein (BSP) antibody confirmed the histological findings of mineralized tissue formation, and hDPSC groups exhibited higher percentage of BSP-positive cells. It can be concluded that PBM improved apexification and favored apexogenesis in necrotic rat molars with an open apex.

Influence of photobiomodulation therapy on root development of rat molars with open apex and pulp necrosis

Abstract This study aimed to evaluate the role of photobiomodulation (PBM) in apexification and apexogenesis of necrotic rat molars with an open apex. Rat molars were exposed to the oral environment for 3 weeks. Canals were rinsed with 2.5% NaOCl and 17% EDTA, filled with antibiotic paste and sealed. After 7 days, canals were rinsed and divided into six groups (n=6): mineral trioxide aggregate (MTA); blood clot (BC); human dental pulp stem cells (hDPSC); MTA+PBM; BC+PBM; and hDPSC+PBM. In hDPSC groups, a 1% agarose gel scaffold was used. Two groups were not exposed: healthy tooth+PBM (n = 6), healthy tooth (n = 3); and one was exposed throughout the experiment: necrotic tooth (n = 3). In PBM groups, irradiation was performed with aluminum gallium indium phosphide (InGaAlP) diode laser for 30 days within 24-h intervals. After that, the specimens were processed for histological and immunohistochemical analyses. Necrotic tooth showed greater neutrophil infiltrate (p < 0.05). Necrotic tooth, healthy tooth, and healthy tooth+PBM groups showed absence of a thin layer of fibrous condensation in the periapical area. All the other groups stimulated the formation of a thicker layer of fibers (p < 0.05). All groups formed more mineralized tissue than necrotic tooth (p < 0.05). PBM associated with MTA, BC, or hDPSC formed more mineralized tissue (p < 0.05). MTA+PBM induced apexification (p < 0.05). Rabbit polyclonal anti-bone sialoprotein (BSP) antibody confirmed the histological findings of mineralized tissue formation, and hDPSC groups exhibited higher percentage of BSP-positive cells. It can be concluded that PBM improved apexification and favored apexogenesis in necrotic rat molars with an open apex.

Evaluation of Apically Extruded Debris using Two Niti Systems Associated with Two Irrigation Techniques in Primary Teeth.

PURPOSE: The aim of this study was to compare the effects of 2 NiTi file systems [Twisted File Adaptive (TFA) and Reciproc (RP)] and 2 irrigation techniques [Conventional needle irrigation (CNI) and Laser activated irrigation (LAI)] on the amount of apically extruded debris in primary maxillary molars. STUDY DESIGN: Sixty extracted primary maxillary molars were randomly divided into 4 groups. The mesio-buccal roots of teeth in 4 groups were instrumented using TFA with LAI, RP with LAI, TFA with CNI and RP with CNI respectively. Debris extruded during instrumentation was collected into Eppendorf tubes and amounts were determined. The data were analyzed using two-way ANOVA test at 0.05 level of significance. RESULTS: The results indicated all instrumentation and irrigation systems caused a measurable apical extrusion of debris. However, no statistically significant difference in debris extrusion was observed between irrigation techniques or instrumentation systems (P > 0.05). The total amount of debris extruded apically by LAI was greater than that by CNI. CONCLUSIONS: All instrumentation and irrigation techniques caused debris extrusion. However, the optimal laser activation time and power settings should be investigated to ensure minimal extrusion of debris and irrigant due to cavitation and pressure during LAI in root canal treatment.

Outcome of Revascularization Procedure: A Retrospective Case Series.

INTRODUCTION: The purpose of this retrospective case series was to investigate the outcome of the revascularization procedure in necrotic immature teeth. METHODS: The residents and faculty members at the University of Pennsylvania endodontic department were invited to submit consecutive revascularization cases treated by them, irrespective of the outcome, during the time period of 2009 to 2012. Twenty-eight of 35 submitted necrotic immature teeth met the inclusion criteria. The treatment protocol included minimal instrumentation and irrigation with 3% sodium hypochlorite and 17% EDTA. Triple antibiotic paste was placed for a minimum of 21 days. After blood clot induction, either EndoSequence Bioceramic Putty (Brasseler, Savannah, GA) or mineral trioxide aggregate was placed below the cementoenamel junction, and composite was used as a final restoration. The follow-up period ranged from 7 to 72 months. The outcome was assessed as complete healing (the absence of clinical signs and symptoms, complete resolution of periradicular radiolucency, increase in the root dentin thickness/length, and apical closure), incomplete healing (the absence of clinical signs and symptoms, the periapical lesion completely healed without any signs of root maturation or thickening, the periapical lesion either reduced in size or unchanged with/without radiographic signs of increasing root dentin thickness/length, or apical closure), and failure (persistent clinical signs and symptoms and/or increased size of the periradicular lesion). RESULTS: Twenty-one of 28 cases (75%) healed completely, 3 cases (10.7%) failed during the observation period and needed further treatment, and 4 cases (14%) presented with incomplete healing. CONCLUSIONS: Within the limitation of this study, the outcome of revascularization, wherein healing of periapical periodontitis and maturation of roots occurs, is fairly high, making it a viable treatment option in comparison with apexification.

Clinical and radiographic outcomes of traumatized immature permanent necrotic teeth after revascularization/revitalization therapy.

INTRODUCTION: Revascularization treatment is rapidly becoming an accepted treatment alternative for the management of endodontic pathology in immature permanent teeth with necrotic dental pulps. However, the success and timing of clinical resolution of symptoms, and radiographic outcomes of interest, such as continued hard tissue deposition within the root, are largely unknown. METHODS: In this prospective cohort study, 20 teeth were treated with a standardized revascularization treatment protocol and monitored for clinical and radiographic changes for 1 year. Standardized radiographs were collected at regular intervals, and radiographic changes were quantified. RESULTS: All 20 treated teeth survived during the 12-month follow-up period, and all 20 also met the clinical criteria for success at 12 months. As a group, the treated teeth showed a statistically significant increase in radiographic root width and length and a decrease in apical diameter, although the changes in many cases were quite small (such that the clinical significance is unclear). The within-case percent change in apical diameter after 3 months was 16% and had increased to 79% by 12 months, with 55% (11/20) showing complete apical closure. The within-case percent change in root length averaged less than 1% at 3 months and increased to 5% at 12 months. The within-case percent change in root thickness averaged 3% at 3 months and 21% at 12 months. CONCLUSIONS: Although clinical success was highly predictable with this procedure, clinically meaningful radiographic root thickening and lengthening are less predictable after 1-year of follow-up. Apical closure is the most consistent radiographic finding.

Assessment of smear layer removal protocols in curved root canals.

This study sought to assess if the final rinse protocol interferes with the smear layer removal in the apical area of curved canals. Sixty-four extracted human mandibular molars with curved mesial roots were instrumented with rotary files and divided into six experimental groups for final rinse: 1EDTA (syringe irrigation with 1 mL of 17% ethylenediaminetetraacetic acid (EDTA) ), 5EDTA (syringe irrigation with 5 mL of 17% EDTA), 1EDTA-P (syringe irrigation with 1 mL of 17% EDTA + pumping with gutta-percha point), 5EDTA-P (syringe irrigation with 5 mL of 17% EDTA + pumping with gutta-percha point), 1EDTA-EA (syringe irrigation with 1 mL of 17% EDTA + EndoActivator) and 5EDTA-EA (syringe irrigation with 5 mL of 17% EDTA + EndoActivator). Final rinsing was carried out over 3 min. The specimens were split lengthwise and observed under a scanning electron microscope using a score criterion. Comparison among the groups showed statistically significant difference only between the 5EDTA-EA group and the other groups (Kruskal-Wallis and Dunn's post-hoc tests, P < 0.05). The combination of 5 mL of 17% EDTA and 3 mL of 2.5% sodium hypochlorite (NaOCl) with the EndoActivator removed smear layer from the apical area of curved root canals more effectively than the other protocols used.

Debris remaining in the apical third of root canals after chemomechanical preparation by using sodium hypochlorite and glyde: an in vivo study.

INTRODUCTION: During chemomechanical instrumentation, several liquid or paste substances are used to ease the action of the files and to eliminate debris and the smear layer. The aim of this study was to evaluate whether the use of a paste containing EDTA during cleaning and shaping of the root canal helps to eliminate debris. METHODS: Twenty root canals in dog teeth were instrumented by a crown-down technique by using nickel-titanium rotary files. In 10 root canals (group A), sodium hypochlorite was used during instrumentation, followed by a final irrigation with 17% liquid EDTA. In another 10 canals (group B), sodium hypochlorite was again used as the irrigating solution, but Glyde File Prep paste was used with every instrument, and a final irrigation with EDTA was also carried out. Two additional teeth were used as positive and 2 as negative controls. The jaws were prepared for histologic evaluation. RESULTS: In group A where Glyde was not used during cleaning and shaping, little or no debris was found in the apical third of the instrumented root canals; however; in group B in which Glyde File Prep paste was used during chemomechanical instrumentation, moderate to high accumulation of debris was observed in the apical third. CONCLUSIONS: The use of Glyde File Prep paste during rotary mechanical instrumentation favors the accumulation of debris in the apical third of the root canals. Irrigation with NaOCl and a final flush with EDTA by means of a small-gauge needle with simultaneous aspiration led to less accumulation of debris than in the Glyde File Prep group (P < .05).

A comparative study of the debridement efficacy and apical extrusion of dynamic and passive root canal irrigation systems.

BACKGROUND: Root canal irrigation carries a risk of extrusion of irrigant into the periapical tissues which can be associated with pain, swelling, and tissue damage. Studies have shown less extrusion with sonic or apical negative pressure devices compared with syringe and side-port needle or passive ultrasonic irrigation with continuous irrigant flow. This study aimed to evaluate the effectiveness of the EndoVac irrigation system, regarding 1) debris removal and 2) the control of apically extruded irrigating solution. METHODS: Fifty extracted human single-rooted teeth were used in this study. The teeth were then randomly divided into three experimental groups according to the type of irrigation used and one control group. In group 1, irrigation was performed using the EndoVac irrigation system. In group 2, irrigation was performed using a 30-gauge, tip-vented irrigation needle. In group 3, irrigation was performed using a 30-gauge, side-vented irrigation needle. The control group received instrumentation with no irrigation to serve as a control for cleaning efficiency. Root canal instrumentation was performed using the Profile NiTi rotary system with a crown-down technique. All of the experimental teeth were irrigated with the same amount of 5.25% sodium hypochlorite. The amount of extruded irrigating solution was then measured by subtracting the post-instrumentation weight from the pre-instrumentation weight using an electronic balance. The cleanliness of debris removal was evaluated using scanning electron microscopy. RESULTS: EndoVac irrigation had the least amount of extrusion followed by the side-vented and tip-vented method. The difference between the groups was statistically significant (P <0.01). As for the cleaning results, the debris collection in the EndoVac and tip-vented groups was the least in the apical third. In the control and the side-vented groups, the debris was the greatest in the apical third, but this difference was not significant among the three experimental groups. CONCLUSIONS: The EndoVac irrigation system extruded significantly less irrigant solution than either needle irrigation system. Debris collection was the least in the apical third for the EndoVac irrigation system. No significant difference was found in the cleaning efficiency among the three irrigation systems.

Removal efficiency of calcium hydroxide dressing from the root canal without chemically active adjuvant.

AIM: Compare the efficiency in removing two calcium hydroxide [Ca(OH)2] preparations from root canal and apical third using single use syringe, ultrasonics and RinsEndo((®)) with saline solution. MATERIALS AND METHODS: One hundred and eighty human singlerooted teeth were instrumented using ProTaper((®)) rotary system, divided into two groups according to Ca(OH)2 filling. A: Powder mixed with water, B: Pulpdent((®)). Each group was divided into three subgroups for the irrigation: A1, B1: Single use syringe; A2, B2: Ultrasonics; A3, B3: RinsEndo((®)). Teeth were split longitudinally, photographed and imported into Adobe Photoshop. The percentage ratios of Ca(OH)2 remaining in the canal and in the apical third were calculated. Data were statistically analyzed using 'ANOVA two-way' and 'univariate tests'. RESULTS: (a) Remnants of medicament were found in all teeth, (b) no statistically significant difference in the elimination of both Ca(OH)2 from the entire canal (p = 0.436), however, mixed powder was better eliminated from the apical third (p = 0.005), (c) no statistically significant difference among the irrigation techniques in the whole canal (p = 0.608), though, RinsEndo((®)) and ultrasonics were the most effective in cleaning the apical third (p = 0.032) when mixed powder was used. CONCLUSION: None of the techniques removed completely Ca(OH)2 from the canal. In the apical third, RinsEndo((®)) and ultrasonics were the most effective when mixed powder was used. CLINICAL SIGNIFICANCE: Ca(OH)2, the most commonly used intracanal dressing, should be completely eliminated before the obturation to assure a good endodontic sealing. Based on the results of this study, RinsEndo((®)) and ultrasonics were the most effective in removal of Ca(OH)2 especially the powder mixed with water presentation.

Regenerative endodontic treatment of permanent teeth after completion of root development: a report of 2 cases.

INTRODUCTION: Clinical regenerative endodontic treatment has been focused on immature necrotic teeth, but it should be extended to mature teeth as an alternative to conventional endodontic treatment. There have been no clinical reports to attempt to revascularize pulp in the entire root canals of mature necrotic teeth. The present report describes the treatment of mature, necrotic, permanent incisors with apical periodontitis by using regenerative endodontic therapy. METHODS: In this case report, modified regenerative endodontic procedures were used to enhance the probability of pulp revasuclarization in mature necrotic teeth. At the first appointment, the root canals were mechanically instrumented to the apices with a large apical size by using the step-back technique and irrigated copiously with antimicrobial solution. Intracanal medicaments (calcium hydroxide or ciprofloxacin) were placed in the root canals. At the following appointment, the root canals were irrigated with antimicrobial solution, and bleeding was induced into the root canals by passing hand files beyond apices. Collagen membranes were placed in the canals as a matrix against which mineral trioxide aggregate was placed. Glass ionomer was used to restore the teeth. The resolution of apical radiolucency and regression of clinical signs and symptoms were observed at recall appointments. CONCLUSIONS: The present report presents modified regenerative endodontic procedures for mature necrotic permanent teeth. Further clinical studies with a large number of cases are needed to investigate the outcome of regenerative endodontic therapy for mature necrotic teeth.

Evaluation of microleakage of root canal fillings irradiated with different output powers of erbium, chromium:yttrium-scandium-gallium-garnet laser.

This study evaluated the root canal seal achieved by irradiation with an erbium, chromium:yttrium-scandium-gallium-garnet laser, and the optimal output power to remove debris and the smear layer were determined. One hundred mandibular premolar teeth were prepared and divided into four groups. Group 1 was not lased but was irrigated with 5 mL of 5.25% NaOCl and 5 mL of 17% ethylenediaminetetraacetic acid. Group 2 was irradiated at a panel setting of 1 W, group 3 at 2 W and group 4 at 2.5 W, with a 50% water level and 48% air-cooling level. Root canals were obturated by cold lateral compaction, and apical microleakage was measured using a fluid filtration model. The remaining debris and smear layer were evaluated via scanning electron microscopy. Statistically significant differences were detected between groups. Irradiation at 1 and 2 W using an erbium, chromium:yttrium-scandium-gallium-garnet laser produced a seal superior to that of the other treatments.

Comparison between two thermoplastic root canal obturation techniques regarding extrusion of root canal filling--a retrospective in vivo study.

OBJECTIVES: The aim of this study was to compare two different thermoplastic techniques--a core-carrier technique (Thermafil) and warm vertical compaction--in terms of overextension of root canal filling in vivo. MATERIALS AND METHODS: Flaring of 88 teeth was conducted using Pro Files .04 as finishing files, and the teeth were obturated using Thermafil. Flaring of 74 teeth was performed using Pro Files .06 as finishing files, and the teeth were obturated using warm vertical compaction. RESULTS: Seventy (80 %) of the teeth obturated using Thermafil and 31 (42 %) teeth obturated using warm vertical compaction show extruded root canal filling. In contrast to Thermafil, there is a higher rate of extruded root canal filling of teeth with more than one root canal using warm vertical compaction. CONCLUSION: Thermafil demonstrated a higher rate of extruded root canal filling compared to warm vertical compaction. Warm vertical compaction is a more predictable method of filling compared to Thermafil. CLINICAL RELEVANCE: Root canal filling extrusion will cause irritation of the surrounding tissue and impair repair processes. In the present in vivo study, there was a higher rate of root canal filling extrusion using Thermafil compared to warm vertical compaction.

In vitro evaluation of apical microleakage of a new MTA-based sealer.

AIM: To evaluate the apical microleakage of a new MTAbased sealer; MTA Fillapex (Angelus) and compare it with ProRoot MTA (Dentsply) and AH Plus (Dentsply). METHODS: 51 single-rooted permanent teeth were selected and the roots were prepared using a rotary system. The samples were divided randomly into 3 groups (n=15). Six roots were used as positive and negative controls. The teeth were obturated with respectively; A. AH Plus and gutta percha (DiaDent); B. MTA Fillapex and gutta percha; C. ProRoot MTA. Specimens were placed in 2% methylene blue dye for 72h. Then linear dye penetration was measured. Measurements were analysed statistically. RESULTS: MTA Fillapex group had significantly higher microleakage values (p<0.05). There were no statistically significant differences between MTA and AH Plus groups (p>0.05). CONCLUSION: The sealing ability of AH Plus and MTA were similar whilst MTA Fillapex showed more microleakage than the other two materials.

Effect of calcium hydroxide on the apical leakage of Resilon-filled root canals: An in vitro study.

Calcium hydroxide is used as an intracanal medication for root canal disinfection and to enhance periapical lesion healing. However, calcium hydroxide remnants can negatively affect the final apical seal of obturated canals. The current study investigated apical leakage in root canals filled with Resilon after calcium hydroxide treatment. Seventy human maxillary central incisors were instrumented to a master apical file size of 40. Teeth were randomly divided into two experimental groups (A and B; n = 30) and two control groups (n = 5). Root canals in group A received a calcium hydroxide dressing, while those in group B received no intracanal medication. One week after treatment, all root canals were obturated with Resilon/Epiphany using lateral compaction. Groups A and B were randomly divided into subgroups A1, A2, B1, and B2 (n = 15). All subgroups were stored in an incubator at 37 degrees C and 100% humidity; subgroups A1 and B1 were stored for one week, while subgroups A2 and B2 were stored for eight weeks. Dye penetration and clearing techniques were used to evaluate apical leakage. Data were analyzed using a Student t-test, with significance set at P < 0.05. Observed apical leakage was significantly higher in subgroup A1 than in subgroups A2 and B1 and in subgroup A2 than in subgroup B2; no statistically significant difference was found between subgroups B1 and B2. When used as an intracanal medication, calcium hydroxide increases the apical leakage of root canals filled with Resilon/Epiphany.

Instrument separation analysis of multi-used ProTaper Universal rotary system during root canal therapy.

INTRODUCTION: The purpose of this study was to identify the influential factors responsible for clinical instrument separation of reused ProTaper Universal rotary instruments (Dentsply Maillefer, Ballaigues, Switzerland). METHODS: Six thousand one hundred fifty-four root canals in 2,654 teeth were prepared using ProTaper Universal files in endodontic clinics. Separation incidence was determined based on the number of treated teeth or canals. Data were collected including the size of fractured instrument, the length and location of a broken segment within the root canal, and the curvature of canal. The chi-square test and independent samples t test were used to determine the statistical significance. RESULTS: The overall instrument separation incidences were 2.6% according to the number of teeth and 1.1% according to the canal number, respectively. Separation incidences according to the number of teeth or canals were significantly higher (P < .05) in molars than those in premolars or anterior teeth. Because of its largest diameter, F3 file presented the highest separation incidence according to the number of teeth (1.0%) or canals (0.4%); 47.5% instrument separation of mandibular molars and 61.5% instrument separation of maxillary molars happened in the mesiobuccal canals. Moreover, 91.4% fragments were located in the apical third of root canals, and 54.2% instrument separation occurred in severely curved canals. There was a significant difference (P < .05) in the mean fracture length between shaping (2.42 ± 0.73 mm) and finishing files (3.32 ± 0.73 mm). CONCLUSIONS: Separation incidence according to the canal number is more reliable than that according to the number of teeth because of the variable canal number in different teeth. The tooth type, rotary file size, canal location, and anatomy were correlated with the instrument separation of reused ProTaper Universal files.

A prospective study of the factors affecting outcomes of nonsurgical root canal treatment: part 1: periapical health.

AIM: To investigate the probability of and factors influencing periapical status of teeth following primary (1°RCTx) or secondary (2°RCTx) root canal treatment. METHODOLOGY: This prospective study involved annual clinical and radiographic follow-up of 1°RCTx (1170 roots, 702 teeth and 534 patients) or 2°RCTx (1314 roots, 750 teeth and 559 patients) carried out by Endodontic postgraduate students for 2-4 (50%) years. Pre-, intra- and postoperative data were collected prospectively on customized forms. The proportion of roots with complete periapical healing was estimated, and prognostic factors were investigated using multiple logistic regression models. Clustering effects within patients were adjusted in all models using robust standard error. RESULTS: proportion of roots with complete periapical healing after 1°RCTx (83%; 95% CI: 81%, 85%) or 2°RCTx (80%; 95% CI: 78%, 82%) were similar. Eleven prognostic factors were identified. The conditions that were found to improve periapical healing significantly were: the preoperative absence of a periapical lesion (P = 0.003); in presence of a periapical lesion, the smaller its size (P ≤ 0.001), the better the treatment prognosis; the absence of a preoperative sinus tract (P = 0.001); achievement of patency at the canal terminus (P = 0.001); extension of canal cleaning as close as possible to its apical terminus (P = 0.001); the use of ethylene-diamine-tetra-acetic acid (EDTA) solution as a penultimate wash followed by final rinse with NaOCl solution in 2°RCTx cases (P = 0.002); abstaining from using 2% chlorexidine as an adjunct irrigant to NaOCl solution (P = 0.01); absence of tooth/root perforation (P = 0.06); absence of interappointment flare-up (pain or swelling) (P =0.002); absence of root-filling extrusion (P ≤ 0.001); and presence of a satisfactory coronal restoration (P ≤ 0.001). CONCLUSIONS: Success based on periapical health associated with roots following 1°RCTx (83%) or 2°RCTx (80%) was similar, with 10 factors having a common effect on both, whilst the 11th factor 'EDTA as an additional irrigant' had different effects on the two treatments.

Comparison of the debridement efficacy of the EndoVac irrigation system and conventional needle root canal irrigation in vivo.

INTRODUCTION: The purpose of this study was to compare the debridement efficacy of EndoVac irrigation versus conventional needle irrigation in vivo. METHODS: Seven adult patients with a total of 22 matched pairs of single-canaled vital teeth with fully formed apices were recruited. Canals were instrumented to a master apical file size #40/.04 taper. One tooth from each matched pair was irrigated by using the EndoVac system. The other tooth was irrigated by conventional needle irrigation. Five additional teeth were used as positive controls. A #10 K-file was inserted into the control canals to determine working length (WL), with no other instrumentation or irrigation performed to confirm the presence of debris. The teeth were extracted, fixed, and decalcified. Six histologic slides each 6 µm thick were made from sections at 1 and 3 mm from WL and stained. The slide with the most debris was photographed at each level for each tooth. A Wilcoxon signed rank test was used to compare the percentage of debris remaining in the canals between the 2 irrigation techniques. RESULTS: The median amount of debris remaining at 1 mm was 0.05% for the EndoVac group and 0.12% for the conventional irrigation group (P < .05). The median amount of debris remaining at 3 mm was 0.09% for the EndoVac group and 0.07% for the conventional needle irrigation group (P > .05). CONCLUSIONS: EndoVac irrigation resulted in significantly less debris at 1 mm from WL compared with conventional needle irrigation. There was no significant difference at the 3-mm level.

Revascularization and periapical repair after endodontic treatment using apical negative pressure irrigation versus conventional irrigation plus triantibiotic intracanal dressing in dogs' teeth with apical periodontitis.

OBJECTIVE: The objective of this study was to evaluate in vivo the revascularization and the apical and periapical repair after endodontic treatment using 2 techniques for root canal disinfection (apical negative pressure irrigation versus apical positive pressure irrigation plus triantibiotic intracanal dressing) in immature dogs' teeth with apical periodontitis. STUDY DESIGN: Two test groups of canals with experimentally induced apical periodontitis were evaluated according to the disinfection technique: Group 1, apical negative pressure irrigation (EndoVac system), and Group 2, apical positive pressure irrigation (conventional irrigation) plus triantibiotic intracanal dressing. In Group 3 (positive control), periapical lesions were induced, but no endodontic treatment was done. Group 4 (negative control) was composed of sound teeth. The animals were killed after 90 days and the maxillas and mandibles were subjected to histological processing. The sections were stained with hematoxylin and eosin and Mallory Trichrome and examined under light microscopy. A description of the apical and periapical features was done and scores were attributed to the following histopathological parameters: newly formed mineralized apical tissue, periapical inflammatory infiltrate, apical periodontal ligament thickness, dentin resorption, and bone tissue resorption. Intergroup comparisons were done by the Kruskal-Wallis and Dunn's tests (alpha = 0.05). RESULTS: Although statistically significant difference was found only for the inflammatory infiltrate (P < .05), Group 1 presented more exuberant mineralized formations, more structured apical and periapical connective tissue, and a more advanced repair process than Group 2. CONCLUSION: From the histological observations, sodium hypochlorite irrigation with the EndoVac system can be considered as a promising disinfection protocol in immature teeth with apical periodontitis, suggesting that the use of intracanal antibiotics might not be necessary.

Treatment options for teeth with open apices and apical periodontitis.

Three clinical cases involving teeth with open apices and apical periodontitis were treated using different protocols. The first case was managed with intracanal calcium hydroxide paste for 12 months before obturation with gutta-percha and sealer. In the second case, an apical plug of mineral trioxide aggregate (MTA) was used before obturation with gutta-percha and sealer and treatment was completed during 2 appointments. In the third case, the tooth, which had a divergent root canal system, was completely obturated with MTA and treatment was also completed over 2 appointments. In all 3 cases, signs of bone healing were observed after treatment.

Root canal morphology of permanent maxillary teeth in the Han nationality in Chinese Guanzhong area: a new modified root canal staining technique.

INTRODUCTION: The purpose of this study was to investigate the canal morphology of 504 maxillary permanent teeth of subjects of Han nationality in Chinese Guanzhong area. METHODS: Maxillary permanent teeth were randomly collected in Guanzhong area. After regular preparation, the teeth were immersed into ink without preparing access cavities and then put into hyperbaric oxygen chamber (0.6 Mpa) for 2 hours to let the ink penetrate into root canal from apical foramen, apical deltas and foramen of lateral canals under stable positive pressure. After demineralization and clearing, the following observations were made: (1) number of root canals, (2) root canal configuration by using Vertucci's classification, (3) presence of lateral canals, and (4) frequency of apical deltas. RESULTS: All the teeth were well-stained, and the fine details were well-revealed. Apical deltas (12.2%-83.3%) and lateral canals (13.7%-68.8%) could be frequently found in all types of maxillary teeth. Most of central incisors (95.8%), lateral incisors (91.4%), and canines (75.4%) displayed type I canal configuration, whereas most of first premolars (87.3%) and second premolars (72.3%) possessed 2 canals with type II, IV, or VI canal configuration. The majority of distobuccal roots and palatal roots of first molars (88.9%, 97.8%), second molars (92.0%, 94.0%), and third molars (87.5%, 91.6%) possessed type I canal configuration. The prevalence of mesiobuccal roots with type I configuration was 66.7% in maxillary first molars, 82% in second molars, and 62.5% in third molars. CONCLUSIONS: The modified technique of canal staining can effectively reveal detailed root canal system. The canal configuration of maxillary teeth in subjects of Han nationality in Chinese Guanzhong area is consistent with previous reports in other races.