Efficacy of IANB and Gow-Gates Techniques in Mandibular Molars with Symptomatic Irreversible Pulpitis: A Prospective Randomized Double Blind Clinical Study.

INTRODUCTION: The aim of the present study was to compare the efficacy of the inferior alveolar nerve block (IANB) and Gow-Gates techniques in mandibular molars with symptomatic irreversible pulpitis. METHODS AND MATERIALS: In this randomised, double-blind clinical trial, 80 patients referred to Mashhad Dental School, were randomly divided into two groups: IANB and Gow-Gates anaesthetic techniques using 2% lidocaine with 1:100000 epinephrine. After injection, if pain during caries/dentin removal and access cavity preparation was reported in each group, the patients once again were randomly allocated to receive buccal or lingual supplementary infiltration. Pain severity was evaluated using a visual analogue scale. The rates of positive aspiration and changes in heart rate were compared between the IANB and Gow-Gates. Paired and individual t-tests and the Mann-Whitney U-test were used to compare the reduction in pain severity. The level of significance was set at 0.05. RESULTS: The success rates of anaesthesia in the Gow-Gates and IANB techniques were 50% and 42.5%, respectively with no significant difference (P=0.562). Supplementary infiltrations significantly reduced pain severity in all subgroups (P<0.05). Lingual infiltration resulted in a significantly greater reduction in pain severity in the IANB group than in the Gow-Gates group (P<0.05). No significant difference in heart rate or positive aspiration results was observed between groups (P>0.05). CONCLUSIONS: In the present study, the efficacy of the IANB and Gow-Gates techniques was comparable in mandibular molars with symptomatic irreversible pulpitis. Supplementary buccal and lingual infiltration significantly reduced pain severity.

The effect of different concentrations of chlorhexidine gluconate on the compressive strength of mineral trioxide aggregate.

Background and aims. Substituting chlorhexidine (CHX) for water has been shown to enhance antimicrobial activity of mineral trioxide aggregate (MTA). The purpose of this study was to compare the compressive strength of MTA mixed with distilled water, 0.12% and 0.2% chlorhexidine. Materials and methods. MTA was mixed according to manufacturer's instructions in group I (n = 20). In groups II & III, 0.12% and 0.2% CHX liquid was substituted for water, respectively. Samples were condensed with moderate force into 20 tubes with 1.5×5 mm dimensions and were allowed to set for 72 hours at 37°C in 100% humidity. After being removed from the molds, their compressive strength was determined using Instron testing machine. Each group was divided into two subgroups according to the time of testing (at 72 hours, and one week). Fractured surfaces of 4 specimens in each group were then evaluated under Scanning Electron Microscope (SEM) to determine their microstructure. One-way ANOVA, Tukey, and paired sample t-test was used for statistical analysis. P < 0.05 was set as significant. Results. There was no significant difference between three groups in terms of their compressive strength after 72 hours. However, the compressive strength of group II was significantly higher than group I (P = 0.034) and group III (P = 0.021) after one week. Crystalline microstructure was similar in all groups. Conclusion. Substitution of 0.012% chlorhexidine for water significantly increased the compressive strength of MTA at 1 week without significant change in crystalline structure.

Mineral trioxide aggregate and portland cement for direct pulp capping in dog: a histopathological evaluation.

Background and aims. Mineral trioxide aggregate and calcium hydroxide are considered the gold standard pulp-capping materials. Recently, Portland cement has been introduced with properties similar to those of mineral trioxide aggregate. Histopathological effects of direct pulp capping using mineral trioxide aggregate and Portland cements on dog dental pulp tissue were evaluated in the present study. Materials and methods. This histopatological study was carried out on 64 dog premolars. First, the pulp was exposed with a sterile bur. Then, the exposed pulp was capped with white or gray mineral trioxide aggregates and white or gray Portland cements in each quadrant and sealed with glass-ionomer. The specimens were evaluated under a light microscope after 6 months. Statistical analysis was carried out using Kruskal-Wallis test. Statistical significance was defined at α=5%. Results. There was no acute inflammation in any of the specimens. Chronic inflammation in white and gray mineral trioxide aggregates and white and gray Portland cements was reported to be 45.5%, 27.3%, 57.1% and 34.1%, respectively. Although the differences were not statistically significant, severe inflammation was observed mostly adjacent to white mineral trioxide aggregate. The largest extent of increased vascularization (45%) and the least increase in fibrous tissue were observed adjacent to white mineral trioxide aggregate, with no significant differences. In addition, the least calcified tissue formed adjacent to white mineral trioxide aggregate, although the difference was not significant. Conclusion. The materials used in this study were equally effective as pulp protection materials following direct pulp capping in dog teeth.

Cone-beam computed tomography evaluation of maxillary first and second molars in Iranian population: a morphological study.

INTRODUCTION: The aim of this in vitro study was to identify the root and canal morphology of maxillary first and second molars in Iranian population by taking and analyzing cone-beam computed tomography (CBCT) scans. METHODS AND MATERIALS: Extracted maxillary first (n=125) and second (n=125) molars were collected from native Iranians and scanned by using a CBCT scanner. The number of roots and configuration of root canal system were classified according to Vertucci's classification. RESULTS: Two (1.6%) maxillary first and two (1.6%) maxillary second molars had four roots. Prevalence of root fusion was 2.4% and 8.8% in maxillary first and second molars, respectively. The most common canal morphology in the mesiobuccal roots of three-rooted first and second molars was type I (46.4% and 80.8%, respectively), followed by type VI (17.6%) in first molars. The predominant morphology of distobuccal and palatal roots in first and second molars was type I. Additional canal types were also identified. CONCLUSION: Profound knowledge of anatomic variations is necessary prior to cleaning and obturation of the root canal system. The most common discovered root morphology was three separate roots in both tooth types. The greatest variation in canal anatomy was discovered in the MB canals of both the first and second molars.

Zinc oxide nano-particles as sealer in endodontics and its sealing ability.

AIMS: The aim of this study was to evaluate the sealing ability of new experimental nano-ZOE-based sealer. SETTINGS AND DESIGN: Three types of nano-ZOE-based sealer (calcined at different temperatures of 500, 600 and 700°C) with two other commercially available sealers (AH26 and micro-sized zinc oxide eugenol sealer) were used. MATERIALS AND METHODS: Zinc oxide nano-particles were synthesized by a modified sol-gel method. The structure and morphology of the prepared powders were characterized using x-ray diffraction (XRD) and transmission electron microscopy (TEM) techniques. The instrumented canals of 60 single-rooted teeth were divided into five groups (n = 10), with the remaining ten used as controls. The canals were filled with gutta-percha using one of the materials mentioned above as sealer. After 3, 45 and 90 days, the samples were connected to a fluid filtration system. STATISTICAL ANALYSIS USED: The data were analyzed using Student's t-test. RESULTS: The XRD patterns and TEM images revealed that all the synthesized powders had hexagonal wurtzite structures with an average particle size of about 30-60 nm at different calcination temperatures. Microleakage in AH26 groups was significantly more than that in three groups of ZnO nano-particles at all the three evaluation intervals. Apical microleakage of ZnO micro-powders was significantly more than that of all the materials, but the sealing ability of ZnO nano-powder sealers did not differ significantly. CONCLUSION: The results of this study showed that the synthesized ZnO nano-powder sealers are suitable for use as a nano-sealer in root canal therapy to prevent leakage; however, further studies should be carried out to verify their safety.

Genotoxicity and cytotoxicity of mineral trioxide aggregate and calcium enriched mixture cements on L929 mouse fibroblast cells.

Mineral trioxide aggregate (MTA) has shown good biocompatibility in several studies. In the present study, the genotoxic and cytotoxic effects of calcium enriched mixture (CEM) were evaluated compared with MTA using MTT and single-cell gel (comet) assays with serial ascending concentrations (0 to 1,000 µg/mL) of tested materials. Cytotoxicity data indicated that there is no significant difference between CEM and MTA at all concentrations except for the full concentration (1,000 µg/mL); CEM had lower cytotoxicity. Genotoxic effects were more evident with CEM at concentrations of 15.6 and 250 µg/mL; however, was less than that of MTA at concentrations of 500 and 1,000 µg/mL. The cytotoxicity and genotoxicity effects of the two experimental groups generally increased with consistency. Under the conditions of this study, CEM is biocompatible in terms of cyto- and genotoxicity. It appears to be an alternative to MTA as an endodontic biomaterial offering several advantages.

Effect of root resection on sealing ability of orthograde apical plugs of mineral trioxide aggregate and calcium enriched mixture.

OBJECTIVE: There is some concern that root resection may alter the seal of the previously set orthograde material. The aim of this study was to evaluate the apical sealing ability of orthograde mineral trioxide aggregate (MTA) and calcium enriched mixture (CEM) plugs after resection of the roots. MATERIALS AND METHODS: The fluid filtration method was carried out on a total of 51 roots in three experimental (n=15) and two control (n=3) groups. The root canals were prepared 3 mm shorter than the working length. In groups A and B, 4 mm of MTA and CEM were placed in an orthograde technique, respectively, and after setting, 3 mm of the root end was resected. In group C, the apical 3 mm of each root was resected, root end preparation was carried out to a depth of 3 mm and filled with MTA. Apical microleakage values of each group were measured. Data was analyzed using Kruskal-Wallis test. RESULTS: Means and standard deviations of apical microleakage in groups A (MTA orthograde), B (CEM orthograde) and C (MTA retrograde) were 2.31×10(-4) (0.32×10(-4)), 3.33×10(-4) (0.29×10(-4)) and 4.42×10(-4) (0.40×10(-4)) µl.min(-1).cmH2o(-1), respectively. The mean values were greater in group C; however, statistical analysis revealed no significant differences between these groups (P>0.05). CONCLUSION: Based on the results of this study, when there is an orthograde access to the root canal and surgery is likely to be necessary in the future, MTA and CEM can be placed in an orthograde technique and it just resects the root during surgery.

The sealing ability of resilon and gutta-percha in severely curved root canals: an in vitro study.

OBJECTIVE: The aim of this study was to compare the apical seal of curved canals obturated with Resilon/Epiphany with gutta-percha/AH Plus. MATERIALS AND METHODS: Thirty-four extracted human mandibular molars with 25-40 degree canal curvature of the mesial root were selected for this study. After preparation, the mesiobuccal canals were obturated with gutta-percha and AH- Plus sealer (group G) or Resilon and Epiphany sealer (group R). Four specimens served as control. Microleakage was evaluated after passing 3 and 30 days using the fluid filtration technique. The data were analyzed statistically using parametric tests. RESULTS: In the 3-day evaluation, the mean microleakage in group R was significantly less than in group G (P< 0.05). After 30 days, there was no significant difference between the two groups (P> 0.05). In group G, the leakage values at the end of 30 days were significantly less than values at the end of 3 days. Although in group R the mean leakage decreased after 30 days, this reduction was not statistically significant. CONCLUSION: Resilon/Epiphany provided a better seal than gutta-percha/AH-Plus in severely curved root canals immediately after obturation, although with the passage of time, Resilon/Epiphany was equivalent to gutta-percha/AH Plus in sealing properties.

Scanning electron microscopic evaluation of dentinal tubule penetration of Epiphany in severely curved root canals.

OBJECTIVE: The purpose of this study was to compare the depth of dentinal tubule sealer penetration in the apical thirds of severely curved root canals obturated with Resilon/Epiphany self-etch (SE) or gutta-percha/AH Plus using scanning electron microscopy. MATERIALS AND METHODS: A total of 34 extracted human mandibular molars with 25-40° curvature of the mesial root canal were selected for this study. After preparation, the mesiobuccal canals were randomly obturated with gutta-percha and AH Plus sealer or Resilon and Epiphany SE sealer. Sealer penetration was evaluated in 2 mm sections of the apical thirds of roots using scanning electron microscopy. Data were analyzed using the independent t-test and Mann-Whitney U-test, with significance set at P < 0.05. RESULTS: Mean tubular penetration depth did not differ significantly between Resilon SE (172.22 µm) and AH Plus (122.18 µm; P > 0.05). The density of sealer tags in the apical thirds of root canals was also equivalent (P > 0.05). CONCLUSION: Average penetration into dentinal tubules in the apical thirds of severely curved roots did not differ significantly between Epiphany SE and AH Plus.

Oral contraceptive misuse as a risk factor for cerebral venous and sinus thrombosis.

BACKGROUND: Consumption of oral contraceptive pills (OCP) is a known risk factor for cerebral venous and sinus thrombosis (CVST) among women. We determined whether misuse of OCP could increase the risk of CVST in women. METHODS: A case-control study was conducted from 2003 to 2007 on 64 female patients with CVST admitted to Al- Zahra medical center and 232 healthy age-matched female OCP users as controls. Patients and controls were interviewed and misuse of OCP was categorized to taking OCP for self-treatment of dysfunctional uterine bleeding, for family planning without physician consult, or for delaying menstruation in purpose of religious customs or traveling, and taking OCP in high dose during the preceding year. RESULTS: Among 64 cases and 232 controls, 30 (46.9 %) and 63 (27.2 %), respectively, had a history of OCP misuse (Odds Ratio = 2.36, 95% Confidence Intervals = 1.33 to 4.18, P = 0.002). Also, using cyproterone compound (Diane) was more frequent in the CVST group (P<0.001). Multivariate analysis controlling for age, OCP misuse, type of OCP, and history of coagulopathy showed that OCP misuse (P<0.001) and using Diane as the OCP (P = 0.006) were both independently associated with CVST. DISCUSSION: OCP misuse can be considered as an additional predisposing factor for CVST among women and partly responsible for larger proportion of female patients with CVST. These findings should alarm the healthcare system to create strategies controlling the inappropriate use of OCP among Iranian women.

Comparative study of the antimicrobial effect of three irrigant solutions (chlorhexidine, sodium hypochlorite and chlorhexidinated MUMS).

AIM: To compare the antimicrobial effect of 2% chlorhexidine, 2.5% sodium hypochlorite and MUMS containing 2% chlorhexidine. MATERIALS AND METHODS: All of the above irrigants were examined on Enterococcus faecalis, Streptococcus mutans, Candida albicans, Lactobacillus casei and E. coli. A total of 0.5 CC of each solution and 0.5 CC of McFarland solution bacterium were added to each examination tube. After 15, 30 and 45 minutes, colony count was performed for each tube. The difference in the number of bacteria indicated the effect taken by disinfectant material. RESULTS: MUMS containing chlorhexidine showed the antimicrobial properties just like chlorhexidine's effect against E. coli, Streptococcus mutans, Candida albicans, Enterococcus faecalis and Lactobacillus casei in preventing these entire microorganisms to incubate. Sodium hypochlorite was not effective against Enterococcus faecalis and Candida albicans incubated in 15, 30 and 45 minutes and Enterococcus faecalis in 15 minutes. CONCLUSION: MUMS has antimicrobial properties similar to chlorhexidine. CLINICAL SIGNIFICANCE: As MUMS containing chlorhexidine can transfer chlorhexidine through its own surfactant around apical area and it can open the dentinal tubules by its own chelator for more penetration of chlorhexidine, it may be a choice for canal irrigation.

Comparison of endodontic biomaterials as apical barriers in simulated open apices.

Objectives. To evaluate the effect of apical foramen diameter and apical barrier thickness on the sealing ability of mineral trioxide aggregate (MTA) and calcium enriched mixture (CEM) plugs in open apices. Materials and Methods. The fluid filtration method was conducted on a total of 136 roots. Samples were randomly divided into two control (n = 8) and four experimental groups (n = 30). Apical foramen diameters measuring 1.1 and 1.7 mm were shaped for groups "1 and 3" and "2 and 4", respectively. In groups 1 and 2 MTA plug and in groups 3 and 4 CEM plug was inserted. The groups were further divided into subgroups according to the thickness of the apical plugs (3- or 5-mm). Microleakage was measured at 1, 7, and 30 days. Results. Mixed ANOVA test showed that the microleakage in groups 1 and 3 as well as all 5-mm plug subgroups were significantly less than groups 2 and 4 (P < 0.05) and 3-mm subgroups (P < 0.05), respectively. Microleakage was significantly lower at 30th day (P < 0.05). Conclusions. Reducing canal diameter or increasing apical plug thickness and the time interval increases the sealing ability of apical barriers. Furthermore, in comparison to MTA, CEM plugs demonstrated superior sealing ability.

Osteoblastic cytokine response to gray and white mineral trioxide aggregate.

INTRODUCTION: The materials used for root-end filling and perforation repair are in direct contact with live tissues e.g. bone and connective tissue; their effects however, are uncertain. The aim of this ex vivostudy was to evaluate the osteoblastic secretory activity adjacent to gray and white mineral trioxide aggregate (MTA) and Intermediate Restorative Material (IRM). MATERIALS AND METHODS: The studied materials were prepared and placed in 24-wells plate. Human MG-63 osteoblasts were introduced to materials after their initial set. The supernatant fluid was collected after 1, 3, and 7 days and the level of interleukin-1ß was measured by ELISA test. A microscopic exam was also performed to assess proliferation and viability of the cells. Kruskal-Wallis and Tukey tests were used for analysis. RESULTS: T here were significant higher levels of interleukin-1ß in the gray and white MTA groups compared to IRM group (P<0.05). The difference in interleukin-1ß secretion level between two mineral trioxide aggregate groups was not significant (P>0.05).Morphologic appearance of osteoblasts adjacent to gray and white MTA was similar to normal osteoblasts in all observation periods, however cells adjacent to IRM were round, signifying cytotoxicity of the adjacent material. CONCLUSION: Human osteoblasts' has a favorable biologic response to white and gray MTA compared to IRM.

Comparison of bupivacaine and lidocaine use for postoperative pain control in endodontics.

INTRODUCTION: Many patients suffer from mild, moderate or severe pain during or after root canal therapy. Theoretically, post-operative pain control can be achieved by using long-acting local anesthetics. The aim of this study was to evaluate the efficacy of a long acting anesthesia, bupivacaine, on preventing post-operative pain associated with endodontic treatment, and to compare it with lidocaine. MATERIALS AND METHODS: This study was a double blind and randomized clinical trial on 30 patients' anterior maxillary teeth. The patients were divided into two groups of fifteen. One group was administered lidocanine (2% with 1:100000 epinephrine) local anesthesia and the other group was given bupivacaine (0.5% without epinephrine). The pain in patients were compared using the visual analogue scale (VAS) at definite times i.e. before treatment, during treatment and 2,4,6,8,10,12,24,36 and 48 hours after operation. Data were analyzed using One-way ANOVA tests. RESULTS: Bupivacaine significantly decreased postoperative pain compared to lidocaine. Postoperative pain was directly related to preoperative pain. Women reported more pain, though significant difference in postoperative pain report was not found between different ages. CONCLUSION: In conclusion, a single dose of bupivacaine 0.5% used in infiltration anesthesia could be more effective in reduction or prevention of post-operative endodontic pain compared with lidocaine.

Evaluation of microleakage following application of a dentin bonding agent as root canal sealer in the presence or absence of smear layer.

The aim of this study was to compare the apical leakage of roots obturated with gutta-percha using either an epoxy resin sealer (AH26) or a dual cure dentin binding agent (Excite DSC) as sealer in the presence or absence of smear layer with fluid filtration method. The canals of eighty-six, single-rooted premolars were instrumented until a #40 K-file fit at working length and then randomly divided into four groups (n = 20) with the remaining six used as controls. Groups 1 and 2 were filled with gutta-percha using AH26 as sealer; groups 3 and 4 were filled with gutta-percha and Excite DSC as sealer. Groups 1 and 3 were smear layer-positive, while group 2 and 4 were designated as smear layer-negative. After 3 days and 3 months, the samples were connected to a fluid filtration system. Analysis of data with the paired t-test showed that microleakage in AH26 groups (with and without smear layer) decreased significantly at 3 months compared to 3 days; however, in the DBA groups, the amount of microleakage at 3 days and 3 months was not significantly different. According to the results of this study, DBA (Excite DSC) had better apical sealing ability and could be applied clinically.

Assembling of fluid filtration system for quantitative evaluation of microleakage in dental materials.

INTRODUCTION: There are several methods for evaluating microleakage in dentistry, for example dye or bacterial leakage, electro-chemical methods, radioisotope labeling and fluid filtration. The purpose of this study was to assemble the fluid filtration system for quantitative evaluation of microleakage in dental materials. MATERIALS AND METHODS: The roots were connected to a tube filled with an underwater pressure supply. A bubble was introduced into the water to measure endodontic leakage. A digital camera and professional software were utilized to record and measure the bubble displacement. RESULTS: Our system was constructed successfully and functioned correctly. CONCLUSION: In this pilot study we found this system efficient for the evaluation of microleakage of dental materials.

Mandibular first molar with four distal canals.

A mandibular first molar with more than four canals is an interesting example of anatomic variations, especially when four of these canals are located in distal roots. This report describes a case of a mandibular first molar with six canals (two mesial and four distal canals in two distal roots). The canals were equipped with a K-file and irrigated with NaOCl (5.25%) and normal saline as the final irrigant. The canals were filled laterally with gutta percha and AH26 sealer (De Trey, Dentsply, Switzerland). This case shows a rare anatomic configuration and points out the importance of looking for additional canals.

An in-vitro evaluation of sealing ability of real seal using fluid filtration.

INTRODUCTION: The aim of this study was to compare the sealing ability of Real Seal (RS) and Gutta-percha (GP). MATERIALS AND METHODS: Forty nine extracted human maxillary central incisors were used. The coronal part of each tooth was removed, the root canal was prepared using the crown down technique and apical enlargement to rotary file # 40. The specimens were randomly divided in to 3 groups of 15 each and two control groups of 2 each. Group 1, was obturated with RS and group 2 and 3 were obturated with GP and AH26 sealer by lateral condensation technique. In group 1 and 3 the smear layer was removed by 5mL of 5.25% NaOCl and 3mL of 17% EDTA. Leakage of the obturated roots was measured using the fluid filtration technique. This method was done at 2 min intervals for 8 min. data were analyzed using ANOVA and Tukey tests. RESULTS: Statistical analysis indicated significant differences between groups 2 with 1 and 3. The most leakage value was observed in the group 2. CONCLUSION: Root canal filling with RS or GP in combination with smear layer removal showed better sealing. Therefore the smear layer has more effect one apical leakage than the obturation system.

Relationship between Duration of Pulp Exposure and Success Rate of Apexogenesis.

INTRODUCTION: Apexogenesis is a way to save vitality of open apex damaged teeth with mild or moderate pulp involvement. Such teeth are not repaired through normal and usual treatments. This treatment provides usual and physiological conditions for root to develop in normal length. The aim of this study was to determine the success rate of apexogenesis according to the duration of pulp exposure. MATERIALS AND METHODS: In this animal study, mineral trioxide aggregate (MTA) and calcium hydroxide (CH) were used. The examined teeth were canines of cats with open apices. The treatment was accomplished in three periods of 1, 3, and 6 weeks after pulpal exposure. Four months later, the results were evaluated histologically and radiographically. RESULTS: The results showed no significant difference between the success rate of MTA and CH. Besides, after 6 weeks of pulpal exposure the treatment was successful. Root development and apical closure was detected in approximately 42% of teeth, while 33% of samples had a healthy Hertwig's sheath. CONCLUSION: The findings of this study suggested that the conservative treatment in traumatized teeth after 1.5 month of pulpal exposure could be successful.