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At least 559 records · Page 31Linked to original sources
PubMed2006

A comparison of the antimicrobial efficacy of NaOCl/Biopure MTAD versus NaOCl/EDTA against Enterococcus faecalis.

The purpose of this investigation was to compare the antimicrobial efficacy of irrigating with 1.3% NaOCl/Biopure MTAD versus irrigation with 5.25% NaOCl/15% EDTA in the apical 5 mm of roots infected with Enterococcus faecalis. Bilaterally matched human teeth were sterilized and inoculated with E. faecalis. After chemomechanical root canal preparation, the root-ends were resected and pulverized in liquid nitrogen to expose E. faecalis in dentinal tubules or other recesses away from the main root canal system. The number of colony forming units (CFU) of E. faecalis per mg was determined from the pulverized root-ends. No significant differences were seen (t = 0.70, p = 0.495) between the number of colony forming units of E. faecalis for teeth irrigated with 5.25% NaOCl/15% EDTA (mean 131 +/- 291 CFU/mg) versus those teeth irrigated with 1.3% NaOCl/Biopure MTAD (mean 187 +/- 237 CFU/mg). This study demonstrated that there is no difference in antimicrobial efficacy for irrigation with 5.25% NaOCl/15% EDTA versus irrigation with 1.3% NaOCl/Biopure MTAD in the apical 5 mm of roots infected with E. faecalis.

Citric Acid↗
PubMed2007

The effect of operator experience in locating additional canals in maxillary molars.

The purpose of this study was to determine the influence of operator experience on the ability to locate and fill extra canals in maxillary first and second molars in vivo. The number of canals located and filled from maxillary first and second molars was recorded from three endodontic residents during the first 6 months of their training, and then compared to the last 6 months of their training in a 2-yr endodontic residency program. Data from each resident was collected and compiled together. The study showed a statistically greater percentage of additional canals located and filled by residents in their last 6 months, as compared to the same residents in their first 6 months in maxillary first and second molars (p < 0.05). Therefore, operator experience was found to improve the ability to locate and fill additional canals in maxillary first and second molars.

Chi-Square Distribution↗
PubMed2006

Determination of the minimum instrumentation size for penetration of irrigants to the apical third of root canal systems.

The purpose of this study was to determine the minimum instrumentation size required for the effective penetration of irrigants and elimination of debris and smear layer from the apical third of the root canals. The mesiobuccal canals of 40 freshly extracted human mandibular first molar teeth were instrumented using the crown-down technique. The teeth were divided into four test groups according to the size of their Master Apical File (#20, #25, #30, #35), and two control groups. After final irrigation, the removal of debris and smear layer from the apical third of root canals was determined under a scanning electron microscope. The data was analyzed using Kruskal-Wallis and Mann-Whitney tests. Based on the results, it appears that the minimum instrumentation size needed for penetration of irrigants to the apical third of the root canal is a #30 file.

Dental Instruments↗
PubMed2006

A retrospective clinical study of incidence of root canal instrument separation in an endodontics graduate program: a PennEndo database study.

This study investigated the incidence of hand and rotary instrument separation (IS) in the endodontics graduate program at the University of Pennsylvania between 2000 and 2004. In 4,865 endodontic resident cases the incidence of hand and rotary IS was 0.25% and 1.68%, respectively. The odds for rotary IS were seven times more than for hand IS. The probability of separating a file in apical third was 33, and 6 times more likely when compared to coronal and middle thirds of the canals. The highest percentage of IS occurred in mandibular (55.5%) and maxillary (33.3%) molars. Furthermore, the odds of separating a file in molars were 2.9 times greater than premolars. Among the ProFile series 29 rotary instruments, the .06 taper # 5 and # 6 files separated the most. There was no significant difference in IS between the use of torque controlled versus nontorque controlled handpieces, nor between first and second year residency.

Bicuspid↗
PubMed2006

Comparison of the shaping ability of RaCe and FlexMaster rotary nickel-titanium systems in simulated canals.

The aim of this study was to compare the shaping ability of RaCe and FlexMaster rotary nickel-titanium instruments in simulated canals. A total of 80 canals with four different shapes were prepared with either RaCe or FlexMaster instruments. Pre- and postoperative images of each canal were recorded and combined using image analysis software. The development of canal aberrations and transportation was assessed. There was a significant difference (p < 0.001) between the systems for time of preparation to apical size 30, .06 taper; FlexMaster instruments took on average 1.86 min and RaCe 1.66 min. One RaCe and two FlexMaster instruments fractured. No zips, elbows, or danger zones were created. One perforation and eight outer widenings were created using FlexMaster instruments; RaCe instruments created two outer widenings. No differences were found between the instruments for direction of transportation. RaCe and FlexMaster nickel-titanium instruments prepared canals rapidly with few aberrations.

Dental Alloys↗
PubMed2006

The effect of formalin storage on the apical microleakage of obturated canals.

Infection control guidelines recommend disinfection of extracted teeth in 10% formalin for 2 weeks before use. Although extracted teeth are routinely used for in vitro endodontic research, the potential influence of formalin has not been evaluated. The purpose of this study was to investigate the effect of formalin storage on the apical seal integrity of obturated canals. There were 100 single-rooted human teeth decoronated, accessed, and randomly divided into four groups. Group 1 was composed of specimens that were instrumented and obturated after extraction without storage in formalin. Groups 2, 3, and 4 were stored in formalin for 2, 4, and 8 weeks, respectively, before treatment. Canals were instrumented to a master apical file size #7 ProFile .04 Taper Series 29 and obturated with Obtura II thermoplasticized gutta-percha and Roth 801 sealer. The teeth were immersed in India ink, cleared, and the greatest extent of linear dye leakage was measured. Microleakage testing displayed significantly less microleakage after 2 and 4 weeks of formalin storage. Leakage measurements after 4 weeks of storage were 62.3% lower than nonfixed specimens. The 8-week storage group demonstrated lower dye penetration compared with the nonfixed group; however, the difference was not statistically significant. Within the scope of this study, storage of extracted teeth in formalin for 2 and 4 weeks resulted in a significant decrease in apical microleakage compared with nonfixed specimens.

Analysis of Variance↗
PubMed2006

Quantitative three-dimensional analysis of root canal curvature in maxillary first molars using micro-computed tomography.

In endodontic therapy, access and instrumentation are strongly affected by root canal curvature. However, the few studies that have actually measured curvature are mostly from two-dimensional radiographs. The purpose of this study was to measure the three-dimensional (3D) canal curvature in maxillary first molars using micro-computed tomography (microCT) and mathematical modeling. Extracted maxillary first molars (46) were scanned by microCT (502 image slices/tooth, 1024 X 1024 pixels, voxel size of 19.5 x 19.5 x 39.0 microm) and their canals reconstructed by 3D modeling software. The intersection of major and minor axes in the canal space of each image slice were connected to create an imaginary central axis for each canal. The radius of curvature of the tangential circle was measured and inverted as a measure of curvature using custom-made mathematical modeling software. Root canal curvature was greatest in the apical third and least in the middle third for all canals. The greatest curvatures were in the mesiobuccal (MB) canal (0.76 +/- 0.48 mm(-1)) with abrupt curves, and the least curvatures were in the palatal (P) canal (0.38 +/- 0.34 mm(-1)) with a gradual curve. This study has measured the 3D curvature of root canals in maxillary first molars and reinforced the value of microCT with mathematical modeling.

Adult↗
PubMed2006

An in vitro evaluation of the apical sealing ability of a new resin-based root canal obturation system.

The purpose of this study was to assess the apical sealing ability of the new resin-based Epiphany-Resilon root canal filling system, and to compare this with the sealing abilities of different pairings of AH plus, gutta-percha, Epiphany, and Resilon. Seventy extracted human single-rooted teeth were used. All teeth were instrumented using a set of ProTaper rotary instruments. The canal spaces were filled with different combinations of core and sealer using lateral condensation, as follows: group 1, AH Plus + gutta-percha; group 2, AH Plus + Resilon; group 3, Epiphany + Resilon; group 4, Epiphany + gutta-percha. Apical leakage quantity was measured with the computerized fluid filtration meter. Statistical analysis indicated that Epiphany gutta-percha combination had the least amount of microleakage than all the other groups; AH Plus gutta-percha combination proved to have second least amount of microleakage among the groups. AH Plus-Resilon combination demonstrated the greatest amount of microleakage. There were a significant difference between Epiphany gutta-percha and AH Plus-Resilon combinations (p < 0.05). It was found that there were no significant differences between Epiphany-Resilon combination and all the other groups (p > 0.05).

Dental Bonding↗
PubMed2006

The effectiveness of different acid irrigating solutions in root canal cleaning after hand and rotary instrumentation.

The goal of this study was to evaluate the cleaning ability of three acid irrigating solutions after hand and rotary instrumentation. Eighty human teeth were randomly divided in eight groups. Four groups were prepared with hand instrumentation and other four with ProTaper. The irrigating solutions were 15% citric acid plus 2.5% NaOCl; 15% EDTA plus 2.5% NaOCl; 5% orthophosphoric acid plus 2.5% NaOCl; and 2.5% NaOCl alone as control. Canal walls were observed with scanning electron microscopy, and photomicrographs were taken in apical, middle, and coronal thirds. A scoring system for debris and smear layer was used. Acid solutions with 2.5% NaOCl were effective in the elimination of smear layer or debris, and no significant differences were showed in smear layer removal between techniques. However, 2.5% NaOCl did not remove smear layer or debris, and no significant differences in debris were observed between manual and rotary techniques.

Acids↗
PubMed2006

Immature teeth with periradicular periodontitis or abscess undergoing apexogenesis: a paradigm shift.

Four clinical cases of immature teeth that developed periradicular periodontitis or abscess underwent a conservative treatment approach, i.e. without canal instrumentation. Instead, only copious 2.5% NaOCl irrigation was performed. All cases presented herein developed mature apices after 7 months to 5 years after the initial treatment without complications, although narrowing canal space was observed. Our clinical observations support a shifting paradigm toward a conservative approach by providing a favorable environment for tissue regeneration. The mechanism of this continued development and formation of the root end is discussed.

Child↗
PubMed2004

A comparison of Profile, Hero 642, and K3 instrumentation systems in teeth using digital imaging analysis.

OBJECTIVE: To evaluate the changes in cross-sectional area morphology of curved canals after instrumentation with Profile((R)), Hero 642((R)), and K3((R)) using digital imaging analysis. Study design Thirty mesial mandibular curved canals were used (25-40 degrees ). The molars were embedded in resin and the roots were sectioned transversely at three levels: apical, middle, and coronal. The canals were randomly distributed into 3 groups for instrumentation using Profile.04 and.06, Hero 642, and K3. The pre- and postinstrumentation sections were digitized and areas corresponding to the canals were measured with image-processing software. RESULTS: Hero eliminated significantly more dentine than K3 and Profile in all 3 sections (P <.01, ANOVA test), with no differences observed between the latter 2 systems (P >.05, Student-Newman-Keuls test). All 3 systems yielded a rounded canal morphology in the coronal, middle, and apical thirds. CONCLUSION: Hero rotary instruments produced more changes in cross-sectional area of the root canal.

Analysis of Variance↗
PubMed2004

Comparison of procedural errors resulting during root canal preparations completed by senior dental students in patients using an '8-step method' versus 'serial step-back technique'.

OBJECTIVE: To compare procedural errors that occur in patients during root canal preparation by senior dental students using a new '8-step method' versus the traditional 'serial step-back technique.' STUDY DESIGN: Senior dental students treated 221 root canals of maxillary and mandibular teeth. Instrumentation included coronal flaring with Gates-Glidden reamers and standardized stainless steel K-files in all teeth. A new 8-step method was used to prepare 67 canals using standardized stainless steel hand instruments (8-step SS) and 69 canals using the rotary Nickel Titanium instruments (8-step NiTi). The traditional serial step-back technique (step-back) was used for 85 root canals. In the apical third, reaming or filing motions were used up to sizes 25 and only reaming motion in sizes larger than 25 with the new 8-step method. A filing motion was used in the step-back for all sizes. Root canals of all groups were obturated with gutta-percha points and AH26 using a lateral condensation technique. Pre- and postoperative radiographs were taken of each tooth. Procedural errors were recorded and statistically analyzed using a binomic test for comparison of proportion. RESULTS: Procedural errors detected consisted of 2 canals with transportation (3%) with the 8-step SS, and 3 canals (4%) with transportation with 8-step NiTi. There were no canal obstructions or instrument separations. With the step-back, 20 canals were transported (24%), 7 canals had obstructions (8%), and in 1 canal instrument was separated (1%). CONCLUSIONS: The new 8-step method resulted in fewer procedural errors than the traditional serial step-back technique when senior students prepared root canals in patients either by hand with standardized K-files or by rotary NiTi instrumentation.

Bismuth↗
PubMed2004

Effects of ultrasonic root end preparation on resected root surfaces: SEM evaluation.

OBJECTIVE: The purpose of this study was to investigate the in vitro effect of ultrasonic retrotips on root end surfaces. STUDY DESIGN: Root end resection was performed on 45 single-root teeth endodontically treated after extraction. Setting the ultrasonic device at full power, a retrograde cavity was made by a stainless steel tip in 9 specimens (SS-FP). In another 9 samples a diamond tip was used (D-FP). Setting the intensity of the ultrasonic device at half power, 9 specimens were treated using stainless steel tips (SS-HP) and 9 using diamond tip (D-HP). Nine teeth were only apically resected and used as controls. Histologic serial sections were examined by scanning electron microsope to assess the number of root-face cracking, the marginal quality, and the crack type. RESULTS: No significant difference between diamond and stainless steel groups was found at a given power setting. Significant differences were found between SS-FP and SS-HP group for both the number of cracks and the marginal quality.

Adolescent↗
PubMed2005

A new quantitative method using glucose for analysis of endodontic leakage.

OBJECTIVE: The purpose of this study was to introduce a new method for quantitative testing of endodontic leakage. STUDY DESIGN: Eighty straight maxillary anterior teeth were divided randomly into 3 experimental groups of 20 samples each and 2 control groups. The experimental groups were prepared using the modified double-flared technique and obturated by lateral compaction of cold gutta-percha with Pulp Canal Sealer EWT, Sealapex, or AH Plus sealer. With the leakage test device, coronal 1 mol/L glucose solution was forced under a hydrostatic pressure of 1.5 kPa toward the apical part of the root. Leakage was measured by the concentration of leaked glucose in apical reservoir at 1, 2, 4, 7, 10, 15, 20, and 30 days with the enzymatic glucose oxidase method. RESULTS: No significant difference of sealing ability was found among 3 test groups at 1, 2, 4, and 7 days. From the tenth day, Pulp Canal Sealer EWT showed the highest leakage, and the leakage was not significantly different between Sealapex and AH Plus. CONCLUSIONS: The quantitative method is sensitive, nondestructive, and clinically relevant. Pulp Canal Sealer EWT showed more leakage than Sealapex and AH Plus in most observation time.

Calcium Hydroxide↗
PubMed2005

Nonsurgical retreatment of teeth with periapical lesions previously managed by either endodontic or surgical intervention.

OBJECTIVE: The purpose of this study was to evaluate the outcome of nonsurgical retreatment of teeth with periapical lesions, which had been previously managed by either endodontic or surgical intervention, and to identify factors that might influence the prognosis. STUDY DESIGN: Seventy-five endodontically and 11 surgically treated teeth with persisting periapical lesions ranging in size from 2 to 11 mm in diameter were included in this study. The teeth were nonsurgically retreated, using calcium hydroxide as intracanal medicament, and were followed for a period of 2 to 8 years. RESULTS: Clinical and radiographic assessment of retreatment showed that complete healing for all cases was 61.6% with an additional category of incomplete healing of 14%; 24.4% failed. The size of the periapical lesions and previous surgical treatment had marginally negative influences on the prognosis, but the differences were not statistically significant. CONCLUSION: The favourable results of this study demonstrated that nonsurgical root canal retreatment is an alternative to surgical intervention of postendodontic or postsurgical failure.

Calcium Hydroxide↗
PubMed2005

Microbial status of apical root canal system of human mandibular first molars with primary apical periodontitis after "one-visit" endodontic treatment.

OBJECTIVE: To assess the in vivo intracanal microbial status of apical root canal system of mesial roots of human mandibular first molars with primary apical periodontitis immediately after one-visit endodontic treatment. The residual intracanal infection was confirmed by correlative light and transmission electron microscopy. STUDY DESIGN: Sixteen diseased mesial roots of mandibular first molars were treated endodontically, each in one visit. Mesio-buccal canals were instrumented using stainless steel hand files and mesio-lingual canals with a nickel-titanium rotary system. The canals were irrigated with 5.25% sodium hypochlorite (NaOCl) during the instrumentation procedures, rinsed with 10 mL of 17% ethylenediamine tetraacetic acid (EDTA), and obturated with gutta-percha and zinc oxide eugenol cement. Thereafter, the apical portion of the root of each tooth was removed by flap-surgery. The specimens were fixed, decalcified, subdivided in horizontal plane, embedded in plastic, processed, and evaluated by correlative light and transmission electron microscopy. RESULTS: Fourteen of the 16 endodontically treated teeth revealed residual intracanal infection after instrumentation, antimicrobial irrigation, and obturation. The microbes were located in inaccessible recesses and diverticula of instrumented main canals, the intercanal isthmus, and accessory canals, mostly as biofilms. CONCLUSIONS: The results show (1) the anatomical complexity of the root canal system of mandibular first molar roots and (2) the organization of the flora as biofilms in inaccessible areas of the canal system that cannot be removed by contemporary instruments and irrigation alone in one-visit treatment. These findings demonstrate the importance of stringent application of all nonantibiotic chemo-mechanical measures to treat teeth with infected and necrotic root canals so as to disrupt the biofilms and reduce the intraradicular microbial load to the lowest possible level so as to expect a highly favorable long-term prognosis of the root canal treatment.

Adolescent↗