Physicochemical, antimicrobial, and biological properties of White-MTAFlow.

OBJECTIVES: To evaluate a new material containing tantalum oxide as an alternative radiopacifier, and a water-based gel for hydration, in comparison with two calcium silicate-based cement: ProRoot MTA and Biodentine. MATERIALS AND METHODS: ProRoot MTA (Dentsply), Biodentine (Septodont), and a new hydraulic calcium silicate cement White-MTAFlow (Ultradent) (in 'thin' consistency) were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS). The interaction with dentin was also assessed using SEM and EDS. Physical and chemical properties radiopacity, setting time, linear flow, volumetric central filling, and lateral flow, pH, and volume change were investigated together with the color luminosity (L) and color change (ΔE). The agar diffusion and direct contact antimicrobial activity, and methylthiazolyldiphenyl-tetrazolium-bromide (MTT) cytotoxicity using human fibroblast cells were also evaluated. Data were statistically analyzed at a 5% significance level. RESULTS: All materials were composed of tricalcium and dicalcium silicate but had different radiopacifiers, and calcium hydroxide (portlandite) deposition was detected in XRD analysis. White-MTAFlow exhibited radiopacity values in accordance with ISO standard, and the longest setting time. The water-based gel provided the highest linear flow, a comparable cavity central filling, and the highest groove-lateral flow in the volumetric flow analysis. White-MTAFlow exhibited an alkalinity reduction, and Biodentine, a progressive increase of pH values after 28 days. However, similar volume loss for White-MTAFlow was assessed in comparison to Biodentine after the 28-day immersion. White-MTAFlow showed the highest L value (91.5), and ProRoot MTA the lowest (78.1) due to dentin staining caused by bismuth migration. None of the materials exhibited inhibition halos against the tested bacteria, and similar turbidity values were obtained after 48 h in direct contact with E. faecalis, indicating an upregulation to bacterial growth. White-MTAFlow showed MTT cytocompatibility similarly to the control group. CONCLUSIONS: White-MTAFlow in 'thin' consistency presents comparable physicochemical, biological, and antimicrobial properties to ProRoot MTA and Biodentine, and does not cause color alteration in dentin. CLINICAL RELEVANCE: White-MTAFlow is a suitable material for use as reparative endodontic cement. Further studies considering its biocompatibility are necessary.

Evaluation of the presence of microorganisms from root canal of teeth submitted to retreatment due to prosthetic reasons and without evidence of apical periodontitis.

AIM: The objective of this study was to evaluate the presence of microorganisms in the root canals (RC) of teeth submitted to endodontic retreatment due to prosthetic reasons and without evidence of apical periodontitis. MATERIAL AND METHODS: Twenty teeth referred to endodontic retreatment due to prosthetic reasons and without evidence of apical periodontitis were included in this study. Gutta-percha (GP) was collected from each third of the RC. After GP removal, microbial samples were also collected from the full extension of RC using paper points and files. The samples were cultivated in Fastidious Anaerobe Agar and the colony-forming units (CFU/mL) were counted. They were also semi-quantitatively analyzed by checkerboard DNA-DNA hybridization using 40 DNA bacterial probes. RESULTS: Microorganisms were found in all samples. The coronal third of GP was more contaminated than the apical third (p ≤ 0.05). There was prevalence of Enterococcus hirae and Enterococcus faecalis in all RC thirds and also in the samples collected from the full extension of RCs. CONCLUSION: Microorganisms were found in all cases referred to endodontic retreatment due to prosthetic reasons and without evidence of apical periodontitis. Enterococcus was the genus most frequently detected. CLINICAL SIGNIFICANCE: An endodontic retreatment should be considered before replacing a prosthesis.

Cytocompatibility of calcium silicate-based sealers in a three-dimensional cell culture model.

OBJECTIVES: The aim of the present study was to evaluate cytotoxic effects and cytokine production of calcium silicate-based sealers (EndoSeal, EndoSequence BC Sealer, and MTA Fillapex) using an in vitro root canal filling model and three-dimensional (3D) cell culture. AH Plus as a reference was compared to contemporary calcium silicate cements regarding cell viability and cytokine production. MATERIAL AND METHODS: Root canals of 30 human maxillary incisors were prepared using a single-file reciprocating technique. The samples were randomly distributed and canals filled with either AH Plus, EndoSeal, EndoSequence BC Sealer, and MTA Fillapex (n = 6). In the negative control group, the root canal remained unfilled. Sealers were placed into the canals along with a gutta-percha cone placed to working length. Balb/c 3T3 fibroblasts, cultured in a type I collagen 3D scaffold, were exposed to filling material and the respective root apex for 24 h. Cytocompatibility of the materials was evaluated using the methyl-thiazoldiphenyl-tetrazolium (MTT) assay. The production of IL-1ß, IL-6, and IL-8 was analyzed using enzyme-linked immunosorbent assay (ELISA). One-way analysis of variance was performed, and when the F-ratios were significant, data were compared by Duncan's multiple-range test. The alpha-type error was set at 0.05. RESULTS: EndoSeal, Endosequence BC Sealer and AH Plus showed cell viability that was similar to the negative control group (P > 0.05), while MTA Fillapex sealer was cytotoxic (P < 0.05). Varying production of IL-1ß, IL-6, and IL-8 was detected in all samples. CONCLUSIONS: In an in vitro root canal filling model with 3D cell culture, AH Plus, EndoSeal, and EndoSequence BC Sealer were cytocompatible. CLINICAL RELEVANCE: These results may suggest that AH Plus, EndoSeal and EndoSequence BC Sealer may achieve better biological response when compared to MTA Fillapex.

Use of soymilk as a storage medium for avulsed teeth.

OBJECTIVE: Tooth avulsion is one of the most severe forms of dental trauma. In these cases, immediate reimplantation is ideal; however, it almost never happens. The purpose of this study was to evaluate the viability of cells stored in soymilk and compare with other several storage media. MATERIALS AND METHODS: The media tested were: long-shelf-life coconut water, long-shelf-life whole milk, long-shelf-life soymilk, Gatorade, egg white, and Hank's Balanced Salt Solution. Cells cultured in DMEM and distilled water served as positive and negative controls, respectively. Plates containing confluent 3T3 fibroblast were soaked in the various media for 2, 12 and 24 h. After incubation at 37°C, viability of the cells was determined using the MTS assay. Data were analyzed by using one-way ANOVA and complemented by Tukey test with a significance level of 5%. RESULTS: Statistical analysis showed that DMEM, whole milk, HBSS and soymilk were the most effective media for maintaining cell viability at all tested times (p < 0.05), followed by coconut water, egg white and Gatorade. The least amount of viable cells was observed in the distilled water group. CONCLUSIONS: The present study shows that the efficacy of soymilk in maintaining the viability of 3T3 fibroblasts is similar to that of HBSS and milk. Therefore, it can be concluded that soymilk could be a suitable alternative storage medium for avulsed teeth.

Bond strength to radicular dentin and sealing ability of AH Plus in combination with a bonding agent.

OBJECTIVE: To evaluate the sealing ability and bond strength of AH Plus sealer associated with the hybridization protocol of radicular dentin with Scotchbond Multi Purpose (SB). MATERIALS AND METHODS: Ninety palatal roots of maxillary molars were selected and divided into three groups (n = 30) according to filling protocol (G1, AH Plus/Resilon; G2, SB/AH Plus/Resilon; and G3, AH Plus/Gutta-Percha). In groups in which AH Plus + resin cones were used, dentin was hybridized before applying sealing material. For the bond strength test, 60 roots of bovine teeth were selected. Six holes were made in each root, two in the cervical, middle and apical third of the root. The roles were filled with AH Plus sealer with or without an adhesive system and submitted to push out test and the fracture mode was examined using a stereomicroscope (×32). RESULTS: Statistical analysis showed that ScotchBond Multi Purpose (SB) + Resilon cone + AH Plus group promoted higher sealing ability than the gutta-percha + AH Plus group (p < 0.05). Bond strength was lower with SB application than without it (p < 0.05). A reverse correlation was found between bond strength and sealing ability. The fracture mode methodology revealed 22.77% of adhesive, 11.67% of cohesive and 65.55% of mixture fractures for SBMP/AH Plus protocol, whereas the AH Plus protocol indicated 86.11% of cohesive and 13.89% of mixed fractures. CONCLUSION: It was concluded that the use of the adhesive system Scotchbond Multi Purpose improved coronal sealing ability of AH Plus, but bond strength of sealer was reduced when adhesive was applied.

A multiparametric assay to compare the cytotoxicity of soy milk with different storage media.

BACKGROUND/AIM: The aim of this study was to evaluate the cytotoxicity of soy milk compared with several other storage media [coconut water, Hank's Balanced Salt Solution (HBSS) and whole milk], assessed through a multiparametric analysis employing 3T3 cells. MATERIALS AND METHODS: Plates containing confluent 3T3 fibroblasts were exposed to the various media for 24 h, at 37°C with 5% CO2, and cell viability was evaluated by a multiparametric assay assessing sequentially, on the same cells, mitochondrial activity (XTT), membrane integrity (neutral red test) and total cell density (crystal violet dye exclusion test). Results from each test were compared by two-way analysis of variance (ANOVA). RESULTS: Statistical analysis showed that whole milk, HBSS and soy milk were the most effective media in maintaining cell viability at all tested times (P < 0.05). The least amount of viable cells was observed when using coconut water. CONCLUSIONS: This study shows that the efficacy of soy milk in maintaining the viability of 3T3 fibroblasts is similar to that of HBSS and milk, as shown by three different cell viability tests.

A nonsurgical technique for the removal of overextended gutta-percha.

AIM: The present report describes and discusses a nonsurgical technique for the removal of overextended gutta-percha. BACKGROUND: Mechanical irritation results from overextension and the overextended material used during root canal obturation could produce an inflammatory reaction with an area of rarefaction in the periapical tissues. The healing process is not affected by the presence of filling materials as it is well tolerate by the periapical tissues, but it is accepted that a higher failure rate is found in overfilled teeth. CASE REPORT: This clinical report describes one case with an overextended gutta-percha cone and a new nonsurgical technique to remove this material. CONCLUSION: The technique described is a conservative, safe and plausible option to remove extruded gutta-percha in periapical area. CLINICAL SIGNIFICANCE: Overextended gutta-percha cones could increase the failure of endodontic therapy. Commonly surgical procedures are indicated to remove this overextended material, but this nonsurgical technique could be a better treatment alternative and could increase the chances of success.

Polymerase chain reaction of Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia in primary endodontic infections.

The aim of this study was to investigate the correlation between endodontic clinical signs and symptoms and the presence of Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia or their association by nested polymerase chain reaction assay. Microbial samples were taken from 50 cases with necrotic pulp tissues in primary infections. DNA was extracted from the samples, which were analyzed for the presence of three endodontic pathogens by using species-specific primers. P gingivalis, T denticola, and T forsythia were detected in 46%, 38%, and 22% of the symptomatic cases, respectively. The bacterial complex composed by T forsythia, P gingivalis, and T denticola was found in 14% of the cases with spontaneous pain, tenderness to percussion, swelling, and pain on palpation. The high prevalence of P gingivalis, T denticola, and T forsythia in the samples examined suggests that these bacteria are related to the etiology of symptomatic periradicular diseases.

Residual effects and surface alterations in disinfected gutta-percha and Resilon cones.

The aim of this study was to evaluate alterations on the surface of gutta-percha and Resilon cones when exposed to 2% chlorhexidine gel (CHX) and 5.25% sodium hypochlorite (NaOCl) and to evaluate their possible antibacterial residual effects against Enterococcus faecalis and Porphyromonas gingivalis. A total of 270 medium tapered cones (135 gutta-percha and 135 Resilon) were selected and divided into three groups, according to the substance (NaOCl, CHX, and sterile saline solution). The cones were immersed in each substance (for 1, 5, 10, 20, and 30 min), rinsed in saline solution, and dried. They were placed onto inoculated agar plates and incubated under specific conditions. Scanning electron microscopy analysis was performed on additional 270 disinfected cones. Another 18 cones were used as controls. Based on the results, it was concluded that Resilon cones exposed to CHX for 10, 20, and 30 min demonstrated residual antibacterial action and that substances did not cause alterations to the cones' surface.

The outcome of endodontic treatment: a retrospective study of 2000 cases performed by a specialist.

The purpose of this study was to evaluate the treatment outcome of initial endodontic treatment and nonsurgical retreatment performed by an endodontic specialist in his private office. A total of 2,000 teeth were examined clinically and radiographically and the results were analyzed statistically by Pearson or Fisher's Exact test and multivariate logistic regression. The multivariate analysis evaluated joint associations among various factors, using logistic regression models. The dependent variable for this analysis was the dichotomous outcome: healed versus disease. The overall endodontic success rate was 91.45%, and the healed rate was significantly higher for initial endodontic treatments than for nonsurgical retreatments; teeth without lesion than for those with lesions; teeth treated without complications than for those with complications; recall period of 18-24 months than for other periods, and teeth with final coronal restoration than for those without. Of the 1376 teeth treated in the initial endodontic treatment sample, the success rate was 94.0%. Multivariate analysis identified the presence of procedural complications (file breakage, perforation and flare-up), as well as the absence of the restorations at follow-ups as the significant predictors of outcome, showing lower rates of success. Of the 624 teeth in the nonsurgical retreatment sample, 85.9% were successful. Stepwise logistic regression analysis revealed that preoperative radiolucency was a strong statistically significant factor to determine lower rates of success than in its absence. Two additional variables (age and tooth type) were found to have a significant influence on the outcome of the retreatment sample. A higher healed rate was observed for the 50-59 years age groups than others, while multirooted (molars) teeth revealed a significantly lower percentage of success than pre-molars and anterior teeth.

Molecular analysis of Filifactor alocis, Tannerella forsythia, and treponema denticola associated with primary endodontic infections and failed endodontic treatment.

The aim of this study was to investigate the presence of strict anaerobes such as Filifactor alocis, Tannerella forsythia, and Treponema denticola in primary and secondary root-infected canals with periapical lesions by molecular analysis and the association of these species with specific endodontic signs and symptoms. Microbial samples were taken from 100 root canals, 50 with necrotic pulp tissues (NPT, primary infection), and 50 with failed endodontic treatment (FET, secondary infection). DNA was extracted from the samples, which were analyzed for the presence of three endodontic pathogens using species-specific primers and PCR. F. alocis were isolated from 23 canals with NPT and 12 canals with FET; T. forsythia from 12 canals with NPT and three canals with FET; T. denticola from 19 canals with NPT and 12 canals with TEP. Suggested associations were found between primary infection and the presence of F. alocis and T. forsythia (both p < 0.05). In particular, associations were found between: pain and F. alocis; swelling and F. alocis; tenderness to percussion and T. forsythia; mobility and T. forsythia and T. denticola; wet canals and F. alocis, T. forsythia, and T. denticola; purulent exsudate and F. alocis, T. forsythia and T. denticola; abscess and F. alocis, T. forsythia, and T. denticola (all p < 0.05). The findings of this study indicated that F. alocis, T. forsythia, and T. denticola seem to be associated with endodontic signs and symptoms. Additionally, F. alocis and T. forsythia were detected more frequently in teeth with necrotic pulp than in teeth with failing endodontic treatment.

Quantification of Lipoteichoic Acid Contents and Cultivable Bacteria at the Different Phases of the Endodontic Retreatment.

INTRODUCTION: The infectious content of root canals, including bacteria and lipoteichoic acid (LTA), cause injuries to the periapical tissues. The purpose of this clinical study was to quantify the levels of both LTA and cultivable bacteria at the different phases of endodontic retreatment (ER) of teeth with post-treatment apical periodontitis. It also aimed to investigate the presence of gram-positive microorganisms before and after chemomechanical preparation (CMP) and intracanal medication (ICM). METHODS: Twenty infected root canals of single-rooted teeth were randomly assigned into 2 groups according to the chemical substance used for CMP (n = 10 per group): chlorhexidine (CHX) group, 2% CHX gel, and the sodium hypochlorite (NaOCl) group, 6% NaOCl. Root canal samples were taken using paper points before (S1) and after CMP (S2) and after 30 days of ICM with calcium hydroxide + 2% CHX gel (S3). Microorganisms were identified by the culture technique using biochemical tests. Cultivable bacteria were determined by counting the colony-forming unit. LTA levels were measured using the enzyme-linked immunosorbent assay (pg/mL). RESULTS: A total of 70 gram-positive species, out of 102 species isolated, were found in the root canals (54 in S1, 4 in S2, and 12 in S3). Enterococcus faecalis was the most frequent isolated taxon in all phases of the ER. LTA (574.0 ± 94.7) and cultivable bacteria (101.2 ± 79.2) were present in all S1 samples. CMP decreased the overall levels of cultivable bacteria by 99.4% and LTA by 24.8% (P < .05), whereas the total overall reduction level of ICM on viable bacteria was 99.5% and on LTA it was 38.6% (P < .05). CMP with 2% CHX gel (CHX group, 99.3%) was more effective (P < .05) than 6% NaOCl (NaOCl group, 92.1%) on bacterial reduction. Likewise, ICM showed a 100% reduction in the CHX group and 98.5% in the NaOCl group. Regarding the reduction of LTA, CMP with 2% CHX gel (CHX group, 26.9%) was more effective (P < .05) than 6% NaOCl (NaOCl group, 22.6%). In addition, ICM showed a 43.2% reduction in the CHX group and 36.2% in the NaOCl group (P > .05). CONCLUSIONS: The reduction rates of bacteria were higher than the LTA. Moreover, gram-positive microorganisms were present in all phases of the endodontic retreatment.

Long-Term Cytotoxicity, pH and Dissolution Rate of AH Plus and MTA Fillapex.

The aim of the present study was to verify the long-term cytotoxic effects of the MTA Fillapex and to compare them with AH Plus. Dissolution rate and pH were also evaluated. Human osteoblast cells were incubated with elutes of fresh specimens from AH Plus and MTA Fillapex, and with elutes of the same specimens for 4 successive weeks. Elute's pH was evaluated at each time point. A multiparametric cell viability assay was performed. For dissolution rate, ISO methodology was used. The results were analyzed by one-way analysis of variance, complemented with the Tukey post-test (p<0.05). No significant difference was found among the materials when fresh mixed (p>0.05). After 1 week, AH Plus became non-cytotoxic on all three evaluated parameters. Conversely, MTA Fillapex remained severely and mildly cytotoxic over the entire experimental period (p<0.05). The dissolution rate of AH Plus was significantly lower than MTA Fillapex at all time points (p>0.05). The pH of AH Plus was significantly lower than MTA Fillapex at the second and third week (p<0.05). In the other tested time points no statistical difference was observed. In conclusion, MTA Fillapex remained cytotoxic after 4 weeks and its cytotoxicity may be related to the high dissolution rate of this material.

Antimicrobial Susceptibility and Characterization of Virulence Genes of Enterococcus faecalis Isolates from Teeth with Failure of the Endodontic Treatment.

INTRODUCTION: The aim of this study was to investigate the prevalence of virulence factors and the antimicrobial resistance of Enterococcus faecalis isolates of teeth with failure of the endodontic treatment. METHODS: Twenty root canal samples were collected from teeth with apical periodontitis. E. faecalis was firstly identified based on phenotypic features and then by 16S ribosomal RNA gene sequencing. The antimicrobial susceptibility was determined by the minimum inhibitory concentration (MIC) of amoxicillin, amoxicillin + clavulanate, azithromycin, benzylpenicillin, ciprofloxacin, clindamycin, chloramphenicol, doxycycline, erythromycin, gentamicin, metronidazole, moxifloxacin, rifampicin, tetracycline, and vancomycin using the E test method. Virulence factors (ace, asa, asa373, cylA, efaA, esp, and gelE) were detected by polymerase chain reaction assay. RESULTS: Amoxicillin + clavulanate was effective against all strains. Intermediate and total resistance was found against the majority of the tested antimicrobials. The susceptibility of some microorganisms to some antimicrobial agents changed according to the evaluation time. MIC50 and MIC90 also varied according to the evaluation time. In relation to the virulence factors of the E faecalis isolates, ace was detected in 100% of the strains, asa (60%), asa373 (15%), efaA (95%), esp (70%), and gelE (75%), whereas cylA was not detected. CONCLUSIONS: It was concluded that E. faecalis isolates from persistent endodontic infections showed varied degrees of intermediate/total resistance to several antimicrobial agents, with amoxicillin + clavulanate being the most effective agent. Moreover, the strains showed different patterns for virulence gene detection.

Quantification of endotoxins in necrotic root canals from symptomatic and asymptomatic teeth.

The purpose of this investigation was to quantify the concentration of endotoxin in necrotic root canals and investigate the possible relationship between the concentration of endotoxin and endodontic signs and symptoms. Samples were collected from root canals of 50 patients requiring endodontic treatment due to necrosis of the pulpal tissue. Anaerobic techniques were used to determine the number of c.f.u. in each sample. A quantitative chromogenic Limulus amoebocyte lysate assay was used to measure the concentration of endotoxin in each sample. The presence of c.f.u. was detected by culture in all samples (range 10(2)-5x10(6)). In samples from cases of patients with spontaneous pain, the mean c.f.u. was 1.43x10(6) while in asymptomatic cases it was 9.1x10(4). Endotoxin was present in all the samples studied [range 2390.0-22100.0 endotoxin units (EU) ml-1]. The mean concentration of endotoxin in samples from patients with spontaneous pain was 18540.0 EU ml-1 while in asymptomatic cases it was 12030.0 EU ml-1. Asymptomatic cases generally had lower levels of endotoxin (i.e. a negative association). A positive association was found between endotoxin and symptomatic cases (e.g. spontaneous pain, tenderness to percussion, pain on palpation, swelling and purulent exudates). This study showed that endotoxin is present in high concentrations in root canals of symptomatic teeth. There was a positive correlation between the concentration of endotoxin in the root canal and the presence of endodontic signs and symptoms.

Evaluation of endodontic treatments performed by students in a Brazilian Dental School.

The aims of this study were to evaluate the clinical outcomes of root canal treatments performed by final-year students in the Dental School of Piracicaba, State University of Campinas, SP, Brazil, during the year 2000 and to evaluate the success rate of these treatments at follow-ups conducted one and three years later (2001-03). All 579 endodontic treatments performed by final-year students were selected for this investigation. Detailed personal and dental history was obtained from the patient's records. Clinical and radiographic follow-up examinations were performed. For 78.8 percent of the cases, dental caries was recorded as the cause for performing endodontic treatment; for 8.8 percent, prosthetic reasons were given; and for 12.4 percent, failure of the endodontic treatment was the reason. The largest percentage (30.7 percent) of recalled patients was examined after one year; the success rate at this follow-up evaluation ranged from 83 percent to 96 percent depending on the pulp status prior to the root canal treatment. After three years, only 8 percent of treated patients returned; assessment for them revealed a 75.5 percent success rate. Dental caries is still the main reason for endodontic treatment. This level of success of the root canal treatment in a Brazilian dental school is similar to other reports in the literature.

Influence of Endodontic Treatment and Coronal Restoration on Status of Periapical Tissues: A Cone-beam Computed Tomographic Study.

INTRODUCTION: This cross-sectional study determined the prevalence of apical radiolucency in 1290 root canal-treated teeth and the correlation between endodontic treatment quality and the presence of coronal restorations with apical radiolucency using cone-beam computed tomographic imaging. METHODS: Cone-beam computed tomographic scans were analyzed, and teeth were classified as healthy or diseased according to the periapical status. Other factors were also evaluated for their association with the apical diagnosis including sex, quality of endodontic treatment, presence of coronal restorations and posts, and apical level of filling. RESULTS: Of the treated teeth, 48.83% were classified as healthy. Only 55.11% of the teeth had endodontic treatment rated as adequate. The quality of endodontic treatment and the presence of coronal restoration were statistically correlated with the presence or absence of an apical radiolucency (P < .0001). Combined data revealed that teeth with both adequate endodontic treatment and the presence of coronal restoration showed significantly better apical status than the other combinations (P < .001). Canals filled up to 0-2 mm short of the apex had a significantly higher number of teeth rated as healthy compared with overfilled or underfilled cases (P = .001). The presence of a post was not found to be a statistical significant factor (P = .81). CONCLUSIONS: Data showed a relatively high prevalence of apical radiolucencies in root canal-treated teeth. The quality of the endodontic treatment, the presence of coronal restoration, and apical extent of the root canal filling were significantly associated with healthy apical tissues.

Frequency of root resorption following trauma to permanent teeth.

This retrospective study evaluated the frequency of development of root resorption in dental trauma cases involving supporting tissue. For 249 traumatized teeth of 125 patients aged between 7 and 51 years, we collected data on the gender and age of the patient, the teeth involved, the type of trauma, and the period between dental injury and initial examination. Radiographic parameters examined in relation to root resorption included the presence of inflammatory external root resorption, internal root resorption, replacement resorption, and canal calcification. Data were analyzed by chi-squared test, Fisher's exact test, and mult iple logistic regression (P < 0.05). The results indicated that there was a significant relationship between the period from the date of injury until initial examination and the occurrence of inflammatory external resorption (P = 0.0199), as well as the type of injury (P = 0.0406). Furthermore, external resorption was most frequently associated with intrusive luxation (92.8%), followed by avulsion (89.0%), lateral luxation (80.2%), and extrusive luxation (77.4%). Among the types of dental injury, replacement resorption was observed more frequently in cases of avulsion (87.2%). The only factor that was significantly associated with this type of resorption was the type of injury (P < 0.0001). Root resorption is observed more frequently and its risk of development is higher in cases of severe trauma, especially avulsion and intrusive luxation.

Efficacy of ethylene-diamine-tetra-acetic acid associated with chlorhexidine on intracanal medication removal: a scanning electron microscopy study.

The aim of this study was to evaluate the effectiveness of 17% ethylene-diamine-tetra-acetic acid (EDTA) used alone or associated with 2% chlorhexidine gel (CHX) on intracanal medications (ICM) removal. Sixty single-rooted human teeth with fully formed apex were selected. The cervical and middle thirds of each canal were prepared with Gates Glidden drills and rotary files. The apical third was shaped with hand files. The specimens were randomly divided into two groups depending on the ICM used after instrumentation: calcium hydroxide Ca(OH)(2) +CHX or Ca(OH)(2) +sterile saline (SS). After seven days, each group was divided into subgroups according to the protocol used for ICM removal: instrumentation and irrigation either with EDTA, CHX+EDTA, or SS (control groups). All specimens were sectioned and processed for observation of the apical thirds by using scanning electron microscopy. Two calibrated evaluators attributed scores to each specimen. The differences between the protocols for ICM removal were analyzed with Kruskal-Wallis and Mann-Whitney U tests. Friedman and Wilcoxon signed rank tests were used for comparison between the score of debris obtained in each root canal third. Remains of Ca(OH)(2) were found in all specimens independently of the protocol and ICM used (P > 0.05). Seventeen percent EDTA showed the best results in removing ICM when used alone (P < 0.05), particularly in those associated with CHX. It was concluded that the chelating agent 17% EDTA significantly improved the removal of ICM when used alone. Furthermore, the type of the vehicle associated with Ca(OH)(2) also plays a role in the ICM removal.

Evaluation of root canal configuration of maxillary molars in a Brazilian population using cone-beam computed tomographic imaging: an in vivo study.

INTRODUCTION: The aim of this study was to analyze and characterize root canal morphology of maxillary molars of the Brazilian population using cone-beam computed tomographic (CBCT) imaging. METHODS: Patients referred for a CBCT radiographic examination for accurate diagnosis and treatment planning were enrolled in the study. A total of 620 healthy, untreated, fully developed maxillary first and second molars were included (314 first molars and 306 second molars). The following observations were recorded: (1) number of roots and their morphology, (2) number of canals per root, (3) fused roots, and (4) primary variations in the morphology of the root canal systems. RESULTS: First and second molars showed a higher prevalence of 3 separate roots, mesiobuccal, distobuccal, and palatal, with 1 canal in each root (52.87% and 45.09%, respectively). Two canals in the mesiobuccal roots represented 42.63% of teeth, whereas mesiobuccal roots of second molars presented 2 canals in 34.32%. The most common anatomic variation in the maxillary first molar was related to the root canal configuration of the mesiobuccal root, whereas the root canal system of the maxillary second molar teeth showed more anatomic variables. CONCLUSIONS: Mesiobuccal roots of maxillary molar teeth had more variation in their canal system than the distobuccal or palatal roots. The root canal configuration of the maxillary second molars was more variable than the first molars in a Brazilian population. CBCT imaging is a clinically useful tool for endodontic diagnosis and treatment planning.