Influence of Using Clinical Microscope as Auxiliary to Perform Mechanical Cleaning of Post Space: A Bond Strength Analysis.

INTRODUCTION: The aim of the present study was to evaluate the influence of using a clinical microscope while performing mechanical cleaning of post space walls on the bond strength of a fiberglass post to dentin. METHODS: Forty-five bovine roots were used. After preparation, roots were filled using gutta-percha and Pulp Canal Sealer (SybronEndo, Orange, CA). Subsequently, for post space preparation, the roots were divided into 3 groups: control (only heat condenser + specific bur of the post system); cleaning without a microscope, mechanical cleaning (after the procedure described in the control group, round burs were used to improve cleaning); and cleaning with a microscope, mechanical cleaning performed with round burs visualized under a clinical microscope. Then, fiberglass posts were cemented. The roots were prepared and evaluated by the push-out test. Data were analyzed using Kruskal-Wallis and Student-Newman-Keuls tests (P < .05). The failure pattern was classified as follows: adhesive between the cement and dentin, adhesive dentin/cement/post, mixed cohesive within dentin, mixed cohesive post, and mixed cohesive post/dentin. RESULTS: The bond strength values (mean ± standard deviation) were control (cervical 1.17 ± 1.1, middle 0.40 ± 0.3, apical 0.52 ± 0.3, and total 0.95 ± 1.9), cleaning without a microscope (cervical 1.66 ± 2.3, middle 0.65 ± 1.1, apical 0.79 ± 1.2, and total1.04 ± 1.7), and cleaning with a microscope (cervical 3.26 ± 2.8, middle 1.97 ± 3.5, apical 1.85 ± 4.1, and total 2.37 ± 3.5). In the cleaning with a microscope group, the bond strength values were significantly higher than those in the other groups. In all groups, the main failure pattern was adhesive between cement and dentin. CONCLUSIONS: The use of a clinical microscope while performing mechanical cleaning during post space preparation improved the bond strength of a fiberglass post to dentin.

Post-traumatic complications of severe luxations and replanted teeth.

AIM: The aim of this study was to evaluate the main post-traumatic complications of severe luxation and replanted teeth using clinical and radiographic analyses. MATERIALS AND METHODS: Eighty-three patients aged between 7 and 55 years old presenting 180 traumatized teeth that suffered extrusive luxation (n=67), lateral luxation (n=69), intrusive luxation (n=10) and tooth avulsion (n=34) followed by replantation were evaluated. The follow-up period was 24 months. The complications examined were: pulp canal obliteration, pulp necrosis and root resorption (infammatory and replacement). Furthermore, the relationship between time elapsed before receiving dental attendance and development of infammatory resorption was observed. RESULTS: Pulp necrosis was the main complication, occurring in 147 teeth (82.7%). All of the teeth that suffered intrusive luxation and tooth avulsion were diagnosed with pulp necrosis, with significant difference in comparison with another traumas (p<0.001/Fisher's exact test). Infammatory root resorption was observed in 20.5% of the cases and replacement resorption was more related to tooth replantation (94.1%), showing significant prevalence among tooth luxations (p<0.001/Fisher's exact test). In addition, it was noted that patients who seek treatment 9 weeks after the trauma episode presented 10 times more chance of developing infammatory resorption when compared with patients who seek treatment soon after dental trauma (Odds ratio test). CONCLUSION: It may be concluded that pulp necrosis was the main post-traumatic complication observed in traumatized teeth and that delay in seeking treatment may damage the prognosis of severe luxation and replanted teeth. CLINICAL SIGNIFICANCE: Clinical studies describing the main complications that may affect traumatized teeth present great relevance to make the population aware of the importance of seeking immediate treatment and to alert the professional to the need for follow-up. When traumatic injuries are diagnosed and treated early, post-traumatic complications may be controlled, allowing conservation of the tooth in oral cavity.

Traumatized immature teeth treated with 2 protocols of pulp revascularization.

INTRODUCTION: Pulp revascularization may be considered a promising alternative for traumatized necrotic immature teeth. The aim of this study was to evaluate traumatized immature teeth treated with 2 protocols of pulp revascularization. METHODS: Twenty-three teeth of young patients (7-17 years old) with necrotic upper incisors caused by dental trauma were divided into 2 groups; one group was treated with triple antibiotic paste (metronidazole, ciprofloxacin, and minocycline) (TAP) (n = 12), and the other was medicated with combination of calcium hydroxide and 2% chlorhexidine gel (CHP) (n = 11). Patients were treated and followed up for a period from 9-19 months in 2 dental institutions for evaluation of clinical and radiographic data. RESULTS: Most of the teeth were affected by lateral luxation (47.8%). Clinical evaluation in group TAP showed significant reduction in spontaneous pain (P = .01), pain on horizontal percussion (P = .007), and pain on palpation (P = .03), whereas group CHP showed significant reduction in pain on vertical percussion (P = .03). Crown discoloration was observed significantly more in teeth of group TAP (83.3%) (P < .002). On radiographic exam, periapical repair was found in all TAP-treated teeth (P = .03). Similarly, the same findings were found for all teeth treated with CHP with exception of 1 tooth (P = .21). Apical closure was significantly observed in both groups (P < .05). Increase in root length was demonstrated in 5 teeth (41.7%) and 3 teeth (27.3%) of groups TAP and CHP, respectively. Thickening of lateral dentinal walls was observed in 5 teeth of each group. CONCLUSIONS: Revascularization outcomes for traumatized patients treated with the tested protocols presented similar clinical and radiographic data. However, TAP caused esthetic problem leading to tooth discoloration, which can be considered a disadvantage when compared with CHP.

Pulp revascularization after root canal decontamination with calcium hydroxide and 2% chlorhexidine gel.

INTRODUCTION: Pulp revascularization may be considered a promising alternative for necrotic immature teeth. Many studies have accomplished passive decontamination associated with an antibiotic paste. To date, there is no report evaluating calcium hydroxide associated with 2% chlorhexidine gel for revascularization therapy. The aim of this case report was to describe a new proposal for pulp revascularization with mechanical decontamination and intracanal medication composed of calcium hydroxide and 2% chlorhexidine gel. METHODS: The patient, a 9-year-old girl, suffered an intrusion associated with pulp exposure caused by an enamel-dentin fracture in her maxillary left central incisor. After diagnosis, treatment consisted of revascularization therapy with gentle manual instrumentation of the cervical and medium thirds of the root in addition to intracanal medication with calcium hydroxide and 2% chlorhexidine gel for 21 days. In the second session, a blood clot was stimulated up to the cervical third of the root canal. Mineral trioxide aggregate (MTA; Angelus, Londrina, Paraná, Brazil) was used for cervical sealing of the canal. Coronal sealing was performed with temporary filling material and composite resin. RESULTS: During the follow-up period, the root canal space showed a progressive decrease in width, mineralized tissue deposition on root canal walls, and apical closure. A cone-beam computed tomography scan taken at the 2-year follow-up confirmed these findings and did not show complete root canal calcification. CONCLUSIONS: This new proposal for revascularization therapy with 2% chlorhexidine gel may be used for the treatment of necrotic immature root canals.

Innovations in endodontic filling materials: guttapercha vs Resilon.

One of the goals of endodontic treatment is to achieve a complete, tridimensional, hermetic sealing of the root canal system to prevent the entry of microorganisms or their products through both the coronal and apical pathways. Gutta-percha is the most widely used material for root canal filling and despite its numerous properties, such as biocompatibility and thermoplasticity, it has however an important limit: the lack of adhesion to the canal walls. Attempts to address this problem have been made over the years by using endodontic cements capable of bonding to canal dentine but their tendency to resorption in time can compromise the quality of treatment. The first step towards a real adhesive endodontic filling(4) is rather recent; in fact, it goes back to 2003 when, on the occasion of the American Dental Association (ADA) Annual Session, Resilon Research LLC introduced a new canal filling adhesive system based on a thermoplastic synthetic resin material called Resilon™. The real innovation of this system is its capacity of creating a core made of Resilon™ bonded to the cement which adheres to dentine walls previously conditioned with a self-etching primer(4) so no changes in the techniques of canal preparation are required. The aim of this study was to evaluate the capacity of two filling materials (gutta-percha and Resilon) to adapt to the canal anatomy, especially on the apical third, using the continuous wave of condensation technique. Our data suggest that in the third apical the gutta-percha best shows rheological properties that are as important as the bond capability.

A 9-year retrospective study of dental trauma in Piracicaba and neighboring regions in the State of São Paulo, Brazil.

PURPOSE: The purpose of this study was to evaluate the occurrence of dentoalveolar trauma during a 9-year period in the Oral and Maxillofacial Surgery Division at Piracicaba Dental School, State University of Campinas in patients from the Piracicaba municipality and neighborhood regions in São Paulo, Brazil. PATIENTS AND METHODS: This retrospective epidemiologic study from January 1999 to December 2007 evaluated all patients who presented at the Oral and Maxillofacial Surgery Division at Piracicaba Dental School with sustained oral and maxillofacial traumatic injuries associated with dentoalveolar trauma. Information regarding age, gender, etiology, use of protective devices such seatbelts, crash helmets, and presence of facial fractures and general trauma, oral condition, stage of dentition, date of trauma, drug abuse, type, teeth affected, and classification of the trauma were gathered from the medical files. Descriptive analysis was conducted. RESULTS: In total, 2,785 patients were analyzed and 542 (19.46%) were included in this study. The male to female ratio was 2.81:1. Most patients presented with oral hygiene as regular (51.85%). Friday, Saturday, and Sunday were the most prevalent days. Smoking was the most common harmful habit analyzed (16.05%) followed by alcohol use (15.87%). Bicycle accidents (26.94%) were the most common cause, followed by falls (22.69%). With regard to protective devices, 31.51% of drivers were wearing seatbelts during the accidents and helmets were used by 84.38% of motorcycle drivers at the moment of injury. One hundred thirty-five facial fractures were associated with dental and dentoalveolar traumas, and the mandible was the facial bone most associated with dentoalveolar trauma. Upper and lower limbs were most frequently associated with general trauma, accounting for 140 (38.78%) and 111 (30.75%), respectively. CONCLUSION: This study shows that dentoalveolar trauma rates and patterns in the Piracicaba municipality and neighborhood regions in São Paulo are similar to other populations. The weekend is the period with the major incidence of dentoalveolar trauma. Alcohol consumption was linked with this type of trauma. Dentoalveolar trauma is involved in and closely related to severe maxillofacial trauma. The use of a helmet is as important as that of a seatbelt. More studies are necessary for a better knowledge and understanding when considering protocols and organization charts in emergency rooms.

The effect of acid etchant type and dentin location on tubular density and dimension.

STATEMENT OF PROBLEM: Coronal and radicular dentin may react differently to the type of acid treatment used when bonding to these substrates. PURPOSE: The purpose of this study was to characterize and compare dentin morphology, tubular density, and cross-sectional area in deep coronal (around an exposed pulp horn) and root canal dentin at the cervical third in the intact state and after acid etching with phosphoric acid or self-etching dentin primer. MATERIAL AND METHODS: Extracted, human, caries-free premolars were fixed. Smear layer-free sections (control) were obtained and divided into 3 groups: left intact, etched with phosphoric acid, or etched with a self-etching primer from a dentin bonding system. Specimens were examined using scanning electron microscopy. Tubular density and cross-sectional area were determined from the images using software. Values were submitted to multifactorial ANOVA (alpha=.05). RESULTS: Tubular density was not significantly affected by acid type or by dentin location. Acid type significantly (P<.001) affected tubular cross-sectional area: phosphoric acid > self-etching resin > intact dentin, irrespective of dentin location. All acid-treated specimens showed demineralization, and irregular surface morphology was not affected by either acid treatment. CONCLUSIONS: Tubular density was not significantly different between deep coronal and root canal dentin nor affected by acid treatment type. Tubular cross-sectional area did not differ between deep coronal or root canal dentin, regardless of acid treatment. Both acid types significantly increased tubular cross-sectional area at both dentin locations, phosphoric acid to a greater degree than the self-etching primer. Root canal dentin did not display peritubular dentin.

Coronal leakage of four intracanal medications after exposure to human saliva in the presence of a temporary filling material.

AIM: To determine the time required for the recontamination of root canals medicated with four different materials. MATERIALS AND METHODS: A total of 60 intact, caries-free, human single-rooted teeth with straight roots were selected for this study. After chemo-mechanical preparation they must be changed in the specimens into seven groups: 10 teeth medicated with calcium hydroxide (Ca(OH) 2) + Camphorated paramonochlorophanol (CPMC) (G.1); 10 medicated with 2.5% Sodium hypochlorite (NaOCL) (G.2); 10 medicated with 2% Chlorhexidine gluconate (CHX) in gel (G.3); 10 medicated with 2% CHX in gel + Ca(OH) 2 (G.4); 10 without intracanal medicament and sealed with a coronal temporary filling (G.5). Five teeth were without intracanal medicament and coronally unsealed, used as the positive control group (PC) (G.6) and 5 teeth with intact crowns used as the negative control group (NC) (G.7). Glass vials with rubber stoppers were adjusted for use. The medicaments were prepared and injected into the root canals using sterile plastic syringes. An apparatus was used to evaluate for 30 days leakage. The chamber was filled with 3 ml of human saliva and Brain Heart Infusion (BHI) broth, incubated at 37 degrees C and checked daily for the appearance of turbidity in the BHI broth. RESULTS: Recontamination was detected after an average time of 2.6 days in group 2, 15.9 days in group 3, 30 days in group 1, 27.6 days in group 4, 2.9 days in group 5, 1 day in the positive control, and there was no contamination in the negative control group. CONCLUSION: The NaOCl group showed the highest worst average of recontamination; on the other hand, high averages were also shown by Ca(OH) 2 + CPMC and Ca(OH) 2 + 2% CHX in gel.

Concentration of hydrogen ions in several calcium hydroxide pastes over different periods of time.

The purpose of this in vitro study was to measure the concentration of hydrogen ions (pH) of calcium hydroxide [(Ca(OH)2] pastes combined with different vehicles over 7 periods of time. The Ca(OH)2 was manipulated with the following vehicles: i: sterile water; ii: iodoform plus sterile water; iii: local anesthetics (Lydocaine 2% with 1: 100,000 epinephrine); iv: polyethyleneglycol; v: glycerin; vi: 2.0% chlorhexidine gel; vii: camphorated paramonochlorophenol (CMCP); viii: (CMCP) + glycerin; and ix: polyethyleneglycol plus CMCP. The pastes were made on a glass plate to toothpaste consistency and the pH was measured at the following times: 5 min, 1, 24, 48 h; 7, 14 and 28 days. The data were statistically analyzed (Kruskal-Wallis at p<0.05). At 5 min, 1 and 24 h, the pH of all tested pastes ranged from 13.05 to 11.16. At 48 h and 7 days the pH of all tested pastes ranged from 11.66 to 8.92. At 14 and 28 days almost all pastes had pH means lower than 10. In conclusion, the mean pH of all tested calcium hydroxide pastes decreased with the time. Pastes made with aqueous vehicles (especially with sterile water), followed by oily vehicles (especially with CMCP + glycerin), held the highest pH means over the periods of time tested.

Antimicrobial effect and pH of chlorhexidine gel and calcium hydroxide alone and associated with other materials.

The purposes of this study were to evaluate the effectiveness of 2% chlorhexidine (CHX) gluconate gel, calcium hydroxide [Ca(OH)2] and their combination with iodoform and zinc oxide powder as intracanal medications against select microorganisms, and to measure the pH changes caused by these medications. Antimicrobial activity was determined by the agar diffusion method. The zones of growth inhibition were measured and the results were analyzed statistically by Kruskal-Wallis test (p<0.05). The pH of the pastes was measured right after preparation, after 24 h and 1 week later. The largest mean zones of microbial inhibition were produced by 2% CHX gel, followed by Ca(OH)2 + 2% CHX gel + iodoform, Ca(OH)2 + 2% CHX gel, Ca(OH)2 + 2% CHX gel + zinc oxide, and Ca(OH)2 + water. The mean pH of all medications stayed above 12.0 during the whole experiment, except for CHX gel (pH=7.0). The results of this study showed that all medications had antimicrobial activity, but the most effective against the tested microorganisms were 2% CHX gel, followed by its combination with Ca(OH)2 and iodoform.

Relationship between clinical-radiographic evaluation and outcome of teeth replantation.

The aim of this retrospective study was to evaluate clinical and radiographic results related to avulsed and replanted teeth in patients who sought treatment at the Dental Trauma Center of the Dental School of Piracicaba, State University of Campinas, Piracicaba, SP, Brazil. One hundred replanted teeth were studied from 48 individuals (18 females and 30 males, with a mean age of 15 years and 9 months). Post-replantation factors (clinical and radiographic) were observed. The clinical aspects evaluated were crown discoloration, pulp necrosis, mobility changes, presence of fistulae and tooth infra-position. Radiographic examination aimed to identify replacement and inflammatory root resorptions, pulp canal obliteration and the presence of radiolucent areas. Depending on clinical and radiographic findings, results were classified as: complete success, acceptable success, uncertain success or failure. During anamnesis, other factors such as stage of root formation, period extra-alveolar, storage medium, type of splintation, and period after replantation time were recorded. The data obtained were statistically analyzed in order to determine the relationship between the post-replantation factors and outcome of teeth replantation. Linear logistic regression revealed that the majority of replanted teeth were associated with root resorptions and its occurrence duplicated proportionally as the time after replantation increased. Based on these findings, replantation procedures must be submitted to an accurate follow-up, as the success of replanted teeth, which already tends to be limited, may be even more jeopardized if cases are not controlled.

Removal of the smear layer from flattened canals using different chemical substances.

This study used scanning electron microscopy to evaluate the flattened root canals of human mandibular incisors cleaned with nickel-titanium instruments and different chemical substances. Teeth were selected and divided randomly into five groups (n = 10) according to the chemical substances used in the biomechanical preparation: 5.25% sodium hypochlorite (Group 1), 5.25% sodium hypochlorite plus a final irrigation with 17% EDTAC (Group 2), EDTA gel combined with 5.25% sodium hypochlorite (Group 3), 2% chlorhexidine gel (Group 4), and 5.25% sodium hypochlorite combined with Glyde File Prep gel (Group 5). Data analysis showed a statistically significant difference (p < 0.001) among groups. Groups 1 and 5 were similar statistically (p > 0.001) and displayed a higher amount of smear layer on canal walls. Samples from Groups 2, 3, and 4 revealed root canal walls without smear layer and exposed dentin tubules. Among the associations tested in this study, 5.25% sodium hypochlorite solution combined with 17% EDTAC, 5.25% sodium hypochlorite combined with EDTA gel, and 2% chlorhexidine gel all were effective substances for removing the smear layer from flattened root canals.

Clinical relevance of trans 1,4-polyisoprene aging degradation on the longevity of root canal treatment.

This in vivo study investigated the time of degradation of root filling material (trans 1,4-polyisoprene) retrieved from endodontically treated teeth and correlated the occurrence of degradation with the longevity of endodontics. Thirty-six root-filled teeth with different filling times (2 to 30 years) and with and without periapical lesions were selected. All teeth presented clinical indication for root canal retreatment. The association among filling time, presence of periapical lesion and root filling material degradation was investigated. Root filling samples were retrieved from the root canals using a Hedströ m file without solvent. The trans 1,4-polyisoprene was isolated by root filling solubilization in chloroform followed by filtration and centrifugation. GPC and FT-IR were the analytical techniques utilized. Degradation of trans 1,4-polyisoprene occurred with time, as a slow process. It is an oxidative process, and production of carboxyl and hydroxyl groups in the residual polymer were observed. Statistically significant decrease of molar mass was observed after 5 (p=0.0001) and 15 (p=0.01) years in teeth with and without periapical lesion, respectively. Bacteria participated in polymer degradation. Gutta-percha aging was proven an important factor for the long-term success of endodontic treatment. The findings of the present study showed that, after 15 years, polymer weight loss may decrease the capacity of the filling mass to seal the root canal space and prevent re-infection, thus compromising significantly the longevity of root canal therapy.

Radiographic prevalence of root canal ramifications in a sample of root canal treatments in a Brazilian Dental School.

The aim of this study was to radiographically investigate the presence of root canal ramifications found after endodontic treatment, and to determine any relationship between their presence and the type of the auxiliary chemical substance used. The study evaluated 1,470 endodontic treatments performed by final year undergraduate students at the Dental School of Piracicaba, State University of Campinas (UNICAMP), SP, Brazil, during the period from 1998 to 2000. The X-rays taken during treatment were evaluated in order to establish the presence of ramifications of the root canal system. The initial X-ray did not show the presence of any canal ramifications. After filling, X-rays showed only 3 ramification types: 3.06% of lateral canals, 2.99% of apical deltas, and 0.1% of interradicular canals. The maxillary premolars showed the highest number of lateral canals (n = 13), followed by mandibular premolars (n = 10) and maxillary incisors (n = 10). Apical deltas were mostly found in mandibular molars (n = 14), followed by maxillary incisors (n = 9). Only mandibular molars had interradicular canals. The detection of ramifications increased with the use of EDTA. However, no statistically significant relationship was found between the type of auxiliary chemical substance used and the number of root canal ramifications detected after root canal filling. It was concluded that the frequency of root canal ramifications found radiographically was low in treatments performed by undergraduate students.

In vitro evaluation of the antimicrobial activity of calcium hydroxide combined with chlorhexidine gel used as intracanal medicament.

The aim of this study was to investigate the antimicrobial activity of calcium hydroxide (Ca(OH)2) combined with 2% chlorhexidine gluconate (CHX) gel against endodontic pathogens and to compare the results with the ones achieved by Ca(OH)2 mixed with sterile water and by CHX gel alone. Two methods were used: the agar diffusion test and the direct contact test. Ca(OH)2 + 2% CHX gel produced inhibitory zones ranging from 2.84 to 6.5 mm, and required from 30 seconds to 6 hours to eliminate all tested microorganisms. However, 2% CHX gel showed the largest microbial growth zones from 4.33 to 21.67 mm, and required 1 minute or less to inhibit all tested microorganisms. A paste of Ca(OH)2 plus sterile water inhibited only the microorganisms with which it was in direct contact and required from 30 seconds to 24 hours to kill all tested microorganisms. In conclusion, 2% CHX gel + Ca(OH)2 showed better antimicrobial activity than Ca(OH)2 manipulated with sterile water.

Root canal microbiota of dogs' teeth with periapical lesions induced by two different methods.

OBJECTIVE: The microbial composition was investigated in root canals of dogs' teeth with periapical lesions induced by 2 different methods: open versus sealed canals. STUDY DESIGN: Teeth from Group I (n = 16) were left open for a week, then sealed with composite resin for 120 days. The teeth from Group II (n = 16) were left open for the same period. Microbiological samples from the root canals were collected and processed by the anaerobic technique for identification and counting of microorganisms after establishment of periapical reactions. RESULTS: Seventy-four cultivable isolates were recovered in sealed canals (Group I). Strict anaerobes accounted for 64.9% of all species isolated, and gram-negative microorganisms accounted for 55.4%. Microbial genera most frequently isolated were Prevotella, Fusobacterium, Peptostreptococcus, Streptococcus, Enterococcus, Clostridium, and Porphyromonas. Statistical analysis by Pearson chi-square or Fisher's test revealed positive association between sealed teeth and strict anaerobes (P < .05). In open canals (Group II), from a total of 58 cultivable isolates, 19% were strict anaerobes and 81% facultative anaerobes, with predominance of gram-positive species (75.8%). Genera most frequently isolated were Streptococcus, Propionibacterium, Staphylococcus, Neisseria, and Prevotella. CONCLUSION: Strict anaerobes were most frequently found in sealed teeth rather than in the teeth with canals left exposed to the oral cavity for 4 months. Therefore, the method that induced periapical inflammatory lesions by intentional oral exposure, followed by tooth sealing, produced root canal microbiota similar to the same found in humans.

Enterococcus faecalis in dental root canals detected by culture and by polymerase chain reaction analysis.

OBJECTIVE: The objective of this study was to investigate the presence of Enterococcus faecalis in endodontic infections by culture and polymerase chain reaction analyses. STUDY DESIGN: Microbial samples were obtained from 50 teeth with untreated necrotic pulps (primary infection) and from 50 teeth with failing endodontic treatment (secondary infection). Culture techniques were used including serial dilution, plating, incubation, and biochemical identification. For PCR detection, samples were analyzed using a species-specific primer of the 16S rDNA and the downstream intergenic spacer region. RESULTS: Culture and PCR detected the test species in 23 of 100 and 79 of 100 of the teeth, respectively. E faecalis was cultured from 2 (4%) of 50 necrotic canals and from 21 (42%) of 50 root-treated canals. PCR detection identified the target species in 41 (82%) and 38 (76%) of 50 primary and secondary infections respectively. CONCLUSION: E faecalis was detected as frequently in teeth with necrotic pulp as in teeth with failing endodontic treatment when a PCR analysis was used.

In vitro assessment of the immediate and prolonged antimicrobial action of chlorhexidine gel as an endodontic irrigant against Enterococcus faecalis.

OBJECTIVE: The aim of this study was to assess in vitro the antimicrobial activity of 2% chlorhexidine gel against Enterococcus faecalis , comparing it to other endodontic irrigants (2% chlorhexidine liquid and 5.25% sodium hypochlorite). STUDY DESIGN: Eighty roots of human mandibular premolars were prepared by serial instrumentation technique, autoclaved, and contaminated for 7 days with E faecalis monocultures. The roots were then divided into 5 groups according to the irrigant substance used during the standardized biomechanical preparation. In order to evaluate the antimicrobial action of the irrigant substances, 3 microbial samples were taken: initial (before the biomechanical preparation); post-treatment (immediately after the biomechanical preparation), and final (7 days after the biomechanical preparation). The microbiological samples were plated to count the colony-forming units (CFU). RESULTS: The 2% chlorhexidine gel and 2% chlorhexidine liquid significantly reduced the E faecalis CFU in the post-treatment and final microbiological samples. The 5.25% sodium hypochlorite also reduced the E faecalis CFU immediately after the root canal instrumentation, but it was not able to keep the root canal free of detectable E faecalis in the final sample. CONCLUSIONS: The 2% chlorhexidine gluconate (gel and liquid) antimicrobial ability was more effective than 5.25% sodium hypochlorite in keeping low CFU of E faecalis for 7 days after the biomechanical preparation.

An investigation of microleakage from root-end fillings in ultrasonic retrograde cavities with or without finishing: a quantitative analysis.

OBJECTIVE: The aim of this study was to make a quantitative assessment of the sealing ability of Super-EBA, IRM, and Pro Root MTA root-end fillings subjected to 3 different finishing techniques. STUDY DESIGN: Eighty-one ultrasonically prepared root-end cavities in human canines were separated randomly into 3 test groups of 27 roots each. The cavities were filled with Super-EBA, IRM, or Pro Root MTA and finished by ball burnishing. Sequentially, 18 roots from each group received a final smoothing with either a 30-fluted tungsten carbide finishing bur or a Zekrya carbide 28-mm bur. Samples were prepared and immersed in 2% methylene blue dye neutral solution for 12 hours. Roots were ground into a powder and prepared for analysis in an absorbency spectrophotometer. RESULTS: The results revealed that Pro Root MTA displayed significantly less mean dye microleakage ( P < .05) than Super-EBA and IRM root-end fillings. The Super-EBA root-end fillings, although presenting a greater mean dye microleakage, did not differ significantly from IRM ( P > .05). The finishing technique did not significantly ( P > .05) affect the incidence of microleakage among the materials tested. CONCLUSIONS: The favorable results obtained with MTA in leakage studies may be related to its good marginal adaptation. Spectrophotometric analysis may provide valuable information about the sealing capacity of root-end fillings. None of the procedures tested were able to avoid leakage, a finding that stresses the importance of the eradication of irritants within the root canal system.

In vitro evaluation of the susceptibility of endodontic pathogens to calcium hydroxide combined with different vehicles.

The aim of this study was to investigate in vitro the antimicrobial activity of calcium hydroxide [Ca(OH)2] in combination with different vehicles against endodontic pathogens. For such purpose, a broth dilution test was performed. Pastes were prepared with Ca(OH)2 powder and the following vehicles: sterile water, glycerin, camphorated monochlorophenol (CMCP), CMCP + glycerin, polyethyleneglycol and CMCP + polyethyleneglycol. The time required for the pastes to produce negative cultures against the tested microorganisms was recorded and analyzed statistically using the Kruskal Wallis test at 5% significance level. Timing for pastes to eliminate the aerobic and facultative anaerobic microorganisms ranged from 6 to 24 h, while strict anaerobic microorganisms were inhibited within 30 s to 5 min. Microbial susceptibility, ranked from weakest to strongest, can be presented as follows: Enterococcus faecalis (the most resistant microorganism), Candida albicans, Staphylococcus aureus, Porphyromonas gingivalis, Porphyromonas endodontalis and Prevotella intermedia (the last two microorganisms required the same time to be eliminated). In conclusion, calcium hydroxide pastes needed more time to eliminate facultative than anaerobic microorganisms. These findings suggest that the antimicrobial property is related both to paste formulation and to microbial susceptibility.