Effect of post space preparation on apical seal: influence of time interval and sealer.

Med Oral Patol Oral Cir Bucal. 2007 Oct;12(6):E464-8

Authors: Corrêa Pesce AL, González López S, González Rodríguez MP

OBJECTIVE: To assess the efficacy of two sealants to preserve the apical seal after root canal preparation and cementation of posts at 24 h or 72 h after endodontic treatment. STUDY DESIGN: Sixty human single-root teeth were instrumented and obturated using lateral compaction technique with EndoFill [30] or AH-Plus) [30] and were prepared in one of three ways, leaving a 3 mm gutta percha remnant in all cases: without cast post preparation, with preparation after 24 h or after 72 h. After cementing the posts, the specimens were thermal cycled at 5 and 55 degrees C in water baths, submerged in 2% methylene blue dye for 72 h, embedded in acrylic resin and cut transversally into three 1-mm apical sections. Dye leakage was quantitatively assessed as the percentage leaked area. RESULTS AND CONCLUSION: Comparison of the apical sections showed significant differences in leakage with both sealers among the three preparation groups (p<0.001). No significant differences between sealers were found in any preparation group or in the same sections.

PMID: 17909515 [PubMed - indexed for MEDLINE]

Apical extrusion of debris by manual and mechanical instrumentation.

Braz Dent J. 2007;18(1):16-9

Authors: Leonardi LE, Atlas DM, Raiden G

The aim of the present study was to assess the presence of apically extruded debris and evaluate the influence of canal curvature on the amount of debris produced by manual and mechanical techniques. Forty single-rooted mature teeth with 15 to 30 degree of root canal curvature were selected. The presence of only one foramen was confirmed using a magnifying lens. A size 15 K-file was placed up to the apical foramen to determine the patency. Working length was determined with the same instrument, 1 mm short of the foramen. According to the employed technique, the groups were labeled as follows: Group 1 - Manual instrumentation with Mor-flex files; Group 2 - Mechanical instrumentation with Cursor and Mor-flex files; Group 3 - Manual instrumentation with Flexi-cut files; Group 4 - Mechanical instrumentation with Cursor and Flexi-cut files. During instrumentation, the root canals were irrigated with 20 mL. Debris extruded through the apical foramen was collected using the Myers and Montgomery technique. The values (in mg) were: Group 1: 0.422 +/- 0.683; Group 2: 0.688 +/- 0.795; Group 3: 0.409 +/- 0.323; Group 4: 0.810 +/- 0.708. Data were analyzed statistically by ANOVA at 5% significance level. There was no statistically significant difference among the groups (p<0.05). No statistically significant differences were found between slight and moderate curvatures in terms of the amount of extruded debris (p>0.05).

PMID: 17639194 [PubMed - indexed for MEDLINE]

A comparative SEM investigation of the smear layer following preparation of root canals using nickel titanium rotary and hand instruments.

J Oral Sci. 2007 Mar;49(1):47-52

Authors: Zand V, Bidar M, Ghaziani P, Rahimi S, Shahi S

The aim of this study was to compare the efficacy of NiTi flex K-file instruments and rotary FlexMaster and Race instruments (short for reamers with Alternating Cutting Edges) in root canal preparation. A total of 75 single rooted teeth with minimum curvature (< 5 degrees ) were selected and divided into three groups, each containing 25 teeth. Canals were prepared with NiTi flex K-file, FlexMaster and Race instruments using crown down preparation technique, up to size #40. After each instrument, the root canals were flushed with 5 ml of 0.5% NaOCl solution. The amount of debris and smear layer was quantified on the basis of Hulsmann method using a scanning electron microscope. Completely cleaned root canals were not found after instrumentation with any of the three instruments. In general, FlexMaster instruments left significantly less debris and smear layer than Race and NiTi flex K-file instruments (P < 0.05). NiTi flex K-files resulted in significantly more smear layer (P < 0.05) compared to Race and FlexMaster instruments only in the apical third of the canal. (J. Oral Sci. 49, 47-52, 2007).

PMID: 17429182 [PubMed - in process]

Apical seal comparison of low-temperature thermoplasticized gutta-percha technique and lateral condensation with two different master cones.

Med Oral Patol Oral Cir Bucal. 2007 Mar;12(2):E175-9

Authors: P&#xE9;rez Heredia M, Clavero González J, Ferrer Luque CM, González Rodríguez MP

AIM: To compare the apical sealing in mesio-buccal canals of extracted molars obturated with low-temperature thermoplasticized gutta-percha or cold lateral condensation techniques using a .06 or a .02 mm/mm tapered gutta-percha master cone. The secondary aim was to evaluate the depth of spreader penetration in root canals using a .06 or a .02 mm/mm tapered gutta-percha master cone. METHODOLOGY: Forty-four mesio-buccal curved canals (25-40 degree) were instrumented with .06 nickel-titanium rotary instruments and randomly distributed into two control groups (n=4) and three experimental groups (n=12) for obturation by the Ultrafil 3D system or by cold lateral condensation with .06 or .02 tapered master cone. Canal sealer AH-Plus was used. The depth of spreader penetration was recorded in millimetres. Roots were covered with two layers of nail polish, immersed in India ink for 7 days, transversally sectioned and examined with a stereomicroscope. Student s t test was used to determine whether there was a difference in spreader penetration between groups. Kruskal-Wallis test was used to determine whether there was a difference in leakage. RESULTS: There were no differences among the three groups (p=0.396), which showed a very similar mean microleakage (0.42, 0.75 and 0.42). The difference in spreader penetration between the groups filled by cold lateral condensation was significant (p=0.001) CONCLUSION: The Ultrafil 3D system and cold lateral condensation techniques with .06 or .02 tapered master cones were equally effective in the apical sealing of curved canals. The spreader penetrated deeper using a .02 mm/mm tapered gutta-percha master cone.

PMID: 17322810 [PubMed - indexed for MEDLINE]

Sealer penetration and marginal permeability after apicoectomy varying retrocavity preparation and retrofilling material.

Braz Dent J. 2006;17(4):323-7

Authors: Winik R, Araki AT, Negrão JA, Bello-Silva MS, Lage-Marques JL

Apicoectomy failure is generally related to inappropriate marginal sealing of the retrocavity, which allows percolation of microorganisms and their products from root canal system to periapex. This study evaluated tubular penetration of canal sealers and marginal permeability after retrocavity irradiation with Er;Cr:YSGG laser and retrofilling with MTA or cyanoacrylate. Twenty-two single-rooted teeth were decoronated and endodontically treated, their apical 3 mm were resected and the root ends were retroprepared with a low-speed bur. Twenty roots were randomly assigned to 4 groups (n=5): GI and GII--retrofilling with MTA and cyanoacrylate, respectively; GIII and GIV--retrocavity irradiation with Er;Cr:YSGG laser (2.78 microm, 4 W, 20 Hz, 70.8 J/cm(2)) and retrofilling with MTA and cyanoacrylate, respectively. The remaining 2 roots served as positive and negative controls. The analysis of rhodamine B dye infiltration (p=0.05) demonstrated that laser irradiation and MTA retrofilling presented significantly higher permeability rates (p<0.05). Retrofilling with cyanoacrylate showed significantly lower permeability, either when laser was used or not on retrocavity. SEM analysis depicted more cyanoacrylate penetration through dentinal tubules when compared to MTA, suggesting a more efficient marginal sealing. Based on these results, it may be concluded that cyanoacrylate provided a less permeable retrofilling regardless of the retropreparation method, suggesting a more favorable condition to the establishment of the periapical healing.

PMID: 17262147 [PubMed - indexed for MEDLINE]

Influence of sodium hypochlorite-based irrigants on the susceptibility of intracanal microbiota to biomechanical preparation.

Braz Dent J. 2006;17(4):310-6

Authors: Soares JA, Pires Júnior DR

This study evaluated the microbiological conditions of root canals, using smears and culture from anterior teeth and premolars with necrotic pulps associated with chronic periapical pathologies, before and after biomechanical preparation (BMP). During double-flared instrumentation, 1, 2.5 and 5% sodium hypochlorite (NaOCl)-based irrigants were used in 3 groups: GI (n=39), GII (n=36) and GIII (n=36), respectively. Before BMP, all cultures were positive and the smears showed microbiologically diverse morphotypes, including fusiforms, pleomorphic, rods, cocci and filaments. Quantitatively, 20, 20 and 23 morphotypes were identified in GI, GII and GIII, respectively). After BMP, the percentages of negative cultures in GI, GII and GIII were 74.2%, 86.3% and 93.4% (p>0.05) and the number of morphotypes decreased to 14, 15 and 5, respectively. All teeth with 2 root canals and/or associated fistulas were microbiologically negative after BMP, regardless of irrigant concentration. Gram-negative morphotypes were more susceptible to the action of irrigants. After irrigation with 5% NaOCl, only structural arrangements consisting of Gram-positive cocci and bacilli persisted. Thus, BMP plus 5% NaOCl offered the best antiseptic potential because in the few positive cultures a significant reduction in the number of microbiological morphotypes was also shown (p<0.05).

PMID: 17262145 [PubMed - indexed for MEDLINE]

Smear layer removal and chelated calcium ion quantification of three irrigating solutions.

Braz Dent J. 2006;17(4):306-9

Authors: Marques AA, Marchesan MA, Sousa-Filho CB, Silva-Sousa YT, Sousa-Neto MD, Cruz-Filho AM

The purpose of this study was to evaluate, by scanning electron microscopy (SEM), smear layer removal and quantify, by atomic absorption spectrophotometry, the amount of calcium ion present in the chelating solutions after their use. Sixteen extracted canines were instrumented using the step-back technique and were assigned to 3 groups according to the irrigating solution used: G1: 1 mL 17% EDTAC between each file; G2: 1 mL 17% CDTA; G3: 1 mL 17% EGTA. The solutions were collected after use. The teeth were cleaved longitudinally, evaluated under SEM and assessed for smear layer by blinded examiners and scored from 1 to 4. In order to quantify calcium ion release, the collected solutions were examined by atomic absorption spectrophotometry. Freidman's test was used for statistical analysis of SEM values and showed that canals irrigated with 17% EDTAC and 17% CDTA had significantly less smear layer throughout the canals than 17% EGTA (p<0.01). For analysis of the collected solutions, Tukey's test was used and showed that EDTAC and CDTA had a greater amount of calcium ions (22.8+/-7.54 and 60.6+/-20.67 microg/mL, respectively) compared to EGTA (70.5+/-14.2 microg/mL) (p<0.01). The association both methodologies may contribute to the understanding of how these solutions act in the root canal.

PMID: 17262144 [PubMed - indexed for MEDLINE]

Ex vivo analysis of the debris remaining in flattened root canals of vital and nonvital teeth after biomechanical preparation with Ni-Ti rotary instruments.

Braz Dent J. 2006;17(3):233-6

Authors: Sasaki EW, Versiani MA, Perez DE, Sousa-Neto MD, Silva-Sousa YT, Silva RG

The purpose of this study was to assess the presence of apical debris remaining in the apical third of flattened root canals of vital and nonvital teeth after biomechanical preparation with Ni-Ti rotary instruments. Fresh-extracted human mandibular incisors were used in this study. The teeth had clinical indication for extraction and were submitted to cold pulp vitality testing and radiographic examination. Eighteen teeth were selected and randomly assigned to two groups (n=9), according to the clinical diagnosis, i.e., pulp vitality or pulp necrosis. The canals were instrumented with the ProTaper NiTi rotary system in the following sequence: S1--up to the middle third; SX--at the cervical third; S2--up to the apical third; and S1, F1, F2, F3--at the working length. The canals were irrigated with 1% sodium hypochlorite, dried and were submitted to the histological processing. Sections from the apical third were analyzed by an optical microscope (X40) that was coupled to a computer where the images were captured and analyzed using specific softwares. A grid was placed over these images to assess the total canal area and the areas with debris. Mann-Whitney U-test showed no statistically significant difference (p>0.05) between the teeth with pulp vitality (6.49 +/- 3.39) and those with pulp necrosis (5.95 +/- 2.22). It may be concluded that the clinical condition of pulp tissue did not interfere with the amount of debris remaining in the apical third of flattened root canals prepared with Ni-Ti rotary instruments.

PMID: 17262131 [PubMed - indexed for MEDLINE]

Retention of radicular posts varying the application technique of the adhesive system and luting agent.

Braz Oral Res. 2006 Oct-Dec;20(4):347-52

Authors: Fonseca TS, Alfredo E, Vansan LP, Silva RG, Sousa YT, Saquy PC, Sousa-Neto MD

This study evaluated in vitro the retention of intracanal cast posts cemented with dual-cure resin varying the application method of the primer/adhesive solution and luting agent in the prosthetic space prepared to receive the posts. Sixty endodontically treated maxillary canines had their crowns discarded, and their roots were embedded in acrylic resin. The prosthetic spaces were prepared with Largo burs mounted on a low-speed handpiece coupled to a parallelometer in order to maintain length and diameter of intraradicular posts constant and to guarantee that the preparations were parallel after casting. Two groups (n = 30) were randomly formed according to the device used to apply the adhesive system: microbrush or standard bristle brush (control). Each group was divided into 3 subgroups (n = 10) according to the technique used to place the luting agent into the root canal: using only a lentulo spiral before setting the post, applying it onto the post surface, or combining both methods. After 72 hours, the tensile force required to dislodge each post was determined by a universal testing machine (Instron 4444) set at a speed of 1 mm/min. The results indicated that the use of the microbrush yielded higher bond strength values (0.1740 +/- 0.04 kN) than those recorded for the bristle brush tip (0.1369 +/- 0.04 kN, p < 0.001). Bonferroni's test demonstrated a higher retention (p < 0.001) in radicular post cemented with the technique that combined both methods (lentulo + post: 0.1787 +/- 0.03 kN) than that obtained with lentulo (0.1461 +/- 0.065 kN) or post (0.1416 +/- 0.03 kN) alone. The interactions between the adhesive system and luting agent application techniques presented statistical difference (p < 0.001). It was concluded that the best performance in terms of tensile strength among the tested conditions was obtained when the adhesive system was applied with a microbrush and the luting agent was taken into the root canal with lentulo spirals alone (0.1961 +/- 0.04 kN) and combining both methods (lentulo + post: 0.1911 +/- 0.02 kN).

PMID: 17242797 [PubMed - indexed for MEDLINE]

In vitro comparison of NiTi rotary instruments and stainless steel hand instruments in root canal preparations of primary and permanent molar.

J Indian Soc Pedod Prev Dent. 2006 Dec;24(4):186-91

Authors: Nagaratna PJ, Shashikiran ND, Subbareddy VV

This study is an attempt to compare the NiTi rotary and K-files hand instrumentation on root canal preparation of primary and permanent molars for their efficiency in preparation time, instrument failure and shaping the canals. About 20 primary mandibular second molar (I) and 20 permanent mandibular first molar (II) were selected. Each was further divided into 10 for K-files (a) and 10 for NiTi (b) groups, respectively. Results showed that preparation time Ib Ia and IIab<IIa, which was highly significant. In instrument failure, Ia (40%), IIa (30%) showed more deformation but not fracture and Ib (10%), IIb (20%) showed fracture, but not deformation. Profiles showed good canal taper and smoothness compared to the K-files. To conclude profile 0.04 taper 29 series, prepared canal rapidly than conventional K-file with good taper, smoothness though the flow was not satisfactory. Instrument failure with K-files was less. In primary teeth preparation time, instrument failure with profile was less compared to the permanent. To conclude it's encouraging to use the profiles in primary teeth.

PMID: 17183182 [PubMed - indexed for MEDLINE]

Accuracy of electronic apex locator in length determination in the presence of different irrigants: An in vitro study.

J Indian Soc Pedod Prev Dent. 2006 Dec;24(4):182-5

Authors: , Muthu MS, Sivakumar N

Determining the root canal length accurately had been a challenge in endodontics. Introduction of apex locators have definitely served as an effective adjuvant to radiographs. This in vitro study had attempted to compare the effectiveness of electronic apex locator in the presence of various canal contents. Comparison of the length determined by apex locators with the radiographic length was also made. The results of the study had shown that the length of root canals can be accurately made irrespective of the canal contents.

PMID: 17183181 [PubMed - indexed for MEDLINE]

A scanning electron microscopic evaluation of different root canal irrigation regimens.

Braz Oral Res. 2006 Jul-Sep;20(3):235-40

Authors: M&#xF4;nika CM, Fröner IC

The purpose of this study was to assess the effectiveness of endodontic irrigants in removing the smear layer from instrumented root canal walls using Scanning Electron Microscopy (SEM). The endodontic irrigants used were: 1% sodium hypochlorite (NaOCl); 1% NaOCl mixed to 17% EDTAC; 2% chlorhexidine gel; and Ricinus communis gel. Photomicrographs of the middle and apical thirds were evaluated with the aid of the Fotoscore - v. 2.0 software. The results indicated that the mixture of sodium hypochlorite and EDTAC completely removed the smear layer from dentinal walls. The other endodontic irrigants were not as efficient in cleansing the root canals.

PMID: 17119706 [PubMed - indexed for MEDLINE]

The role of Carisolv and different auxiliary chemical substances in the removal of bovine root canal smear layer.

J Oral Sci. 2006 Sep;48(3):99-103

Authors: Antonio AG, Maia LC, Primo LG, Moraes RS, Cunha CB

To evaluate the effectiveness of Carisolv and different auxiliary chemical substances in root canal smear layer (SL) removal. SL was produced in the centre of 40 hemi-disks of bovine root dentine. The samples were divided into four irrigation groups (G): GI (control) - 0.9% NaCl; GII - 1% NaOCl + 0.9% NaCl; GIII - Carisolv + 0.9% NaCl; GIV - 1% NaOCl + 10% citric acid solution + 0.9% NaCl. The photomicrographs (SEM analysis) were coded (0 - absence of SL; 1 - moderate SL; 2 - dense SL with visible tubules; 3 - dense SL with no visible tubules). GIV was more effective in SL removal (P < 0.01). It should be noted that GI and GIII obtained score 3 in 100% of the samples (P > 0.01). Conclusion: NaOHCl, citric acid and NaCl solutions, when used together, presented a better performance in the removal of SL when compared to the other solutions.

PMID: 17023740 [PubMed - indexed for MEDLINE]

A comparison of the efficacy of Er,Cr:YSGG laser and rotary instrumention in root canal debridement.

J Am Dent Assoc. 2006 Sep;137(9):1261-6

Authors: Radatti DA, Baumgartner JC, Marshall JG

BACKGROUND: The authors evaluated the efficacy of an erbium,chromium: yttrium,scandium,gallium,garnet (Er,Cr:YSGG) laser-powered hydrokinetic system (HKS) versus that of rotary instrumentation for root canal d&#xE9;bridement. METHODS: The authors studied four uninstrumented controls and two test groups of 18 matched pairs of teeth. Teeth from each pair underwent different instrumentation but received identical irrigation solutions. The instrumentation protocol involved either rotary instrumentation or the Er,Cr:YSGG laser. The irrigation groups received 0.5 milliliter of distilled water or 5.25 percent sodium hypochlorite (NaOCl) between instruments. The authors measured the amount of debris remaining at 2 and 4 mm from the apex as a percentage of total lumen area. RESULTS: Lased canals had significantly more debris than did canals that received rotary instrumentation (Wilcoxon signed rank test, P < .001). With distilled water irrigation, the debris remaining in lased canals at both the 2-and 4-mm levels was not statistically different from that remaining in uninstrumented controls. Rotary instrumentation yielded significantly less remaining debris than did laser instrumentation (Wilcoxon signed rank test, P < .001). With 5.25 percent NaOCl irrigation, there was no difference in remaining debris between the two groups (Wilcoxon signed rank test , P < .001). The lased group received significantly more irrigant than did the rotary group (Wilcoxon rank sum test, P < .001). CONCLUSIONS: This study indicates that the débridement efficacy of the HKS with distilled water irrigation is unacceptable; with 5.25 percent NaOCl irrigation, it is similar to that of rotary instrumentation. CLINICAL IMPLICATIONS: If the HKS is to be used for d&#xE9;bridement, then NaOCl irrigation must be used for predictable tissue removal.

PMID: 16946431 [PubMed - indexed for MEDLINE]

Effectiveness of rotary and hand files in gutta-percha and sealer removal using chloroform or chlorhexidine gel.

Braz Dent J. 2006;17(2):139-43

Authors: Bueno CE, Delboni MG, de Araújo RA, Carrara HJ, Cunha RS

The purpose of this study was to assess in vitro the efficacy of nickel-titanium K3 rotary files and hand files for removal of gutta-percha and sealer from obturated root canals using either chloroform or chlorhexidine as solvents. Sixty extracted single-rooted bovine teeth with straight, large canals were prepared, obtured and randomly assigned to 3 groups (n=20). The teeth were stored at 37 degrees C for 1 month and then the gutta-percha and sealer were removed using different techniques, as follows. Group I: size 3 Gates-Glidden drills plus size 30 hand K-files and Hedström files and chloroform; Group II: K3 NiTi rotary files and chloroform; and Group III: K3 NiTi rotary files and 2% chlorhexidine gel. Radiographs were taken and scanned and the images were digitized. The total area of the canal and the area with remaining obturation material were measured in millimeters using a computed image analysis system (ImageLab). Data were analyzed statistically by one-way ANOVA and Tukey test at 5% significance level. The groups differed statistically (p<0.05) with respect to the average percentage of remaining gutta-percha and sealer, presenting the following sequence of effectiveness (from most to least effective): Group I (15.48%), Group II (28.42%) and Group III (35.96%). The findings of this study showed that, despite the technique used for removal of filling material, none of the retreated canals were completely free of gutta-percha and sealer remnants. The use of stainless steel hand files resulted in a lesser amount of filling debris than the use of nickel-titanium rotary instruments.

PMID: 16924342 [PubMed - indexed for MEDLINE]

Evaluation of the antimicrobial activity of each component in Grossman's sealer.

Braz Oral Res. 2006 Apr-Jun;20(2):127-31

Authors: Savioli RN, Pecora JD, Mian H, Ito IY

The antimicrobial activity of Grossman's sealer and its components was evaluated on 13 different strains using the double layer well-diffusion method. Results revealed that Grossman's sealer presented antimicrobial activity against all the tested strains. Among the components of the cement, sodium tetraborate presented the greatest antimicrobial activity, both in type and diameter of the halo and ring of inhibition. Sealer powder, rosin, and eugenol presented similar activity, with no effect on P. aeruginosa and C. albicans. Among these, only eugenol had an effect on E. coli. Zinc oxide was only active against S. sobrinus and E. coli. Barium sulfate and bismuth subcarbonate did not show any antimicrobial effect.

PMID: 16878205 [PubMed - indexed for MEDLINE]

Effect of rotary instrumentation and of the association of calcium hydroxide and chlorhexidine on the antisepsis of the root canal system in dogs.

Braz Oral Res. 2006 Apr-Jun;20(2):120-6

Authors: Soares JA, Leonardo MR, da Silva LA, Tanomaru Filho M, Ito IY

This study aimed at evaluating the antisepsis of the root canal system (RCS) and periapical region (PR) provided by rotary instrumentation associated with chlorhexidine + calcium hydroxide as intracanal medicament. Chronic periapical lesions were induced in 26 pre-molar roots in two dogs. After microbiological sampling, automatic instrumentation using the Profile system and irrigation with 5.25% sodium hypochlorite solution, with a final rinse of 14.3% EDTA followed by profuse irrigation with physiological saline were carried out in 18 root canals. After drying the canals, a paste based on calcium hydroxide associated with a 2% chlorhexidine digluconate solution was placed inside them. After 21 days, the medication was removed, leaving the root canals empty and coronally sealed. After 96 hours, a final microbiological sample was obtained, followed by histomicrobiological processing by the Brown & Brenn method. Eight untreated root canals represented the control group (C-G). Based on the Mann-Whitney test at a confidence level of 5% (p < 0.05), the procedures of antisepsis used offered significant efficacy (p < 0.05) resulting in 100.0% of the canals free of microorganisms. In the C-G, an elevated incidence of various microbial morphotypes was confirmed in all sites of the RCS, with the presence of microbial colonies in the periapical region. In contrast, the experimental group showed a similar pattern of infection in the RCS, although less intense and a reduced level of periapical infection (p < 0.05). It was concluded that adequate instrumentation followed by the application of calcium hydroxide + chlorhexidine offered significant elimination of microorganisms.

PMID: 16878204 [PubMed - indexed for MEDLINE]

An in vitro comparative study of apically extruded debris resulting from conventional and three rotary (Profile, Race, FlexMaster) instrumentation techniques.

J Oral Sci. 2006 Jun;48(2):85-8

Authors: Zarrabi MH, Bidar M, Jafarzadeh H

Canal preparation is one of the most important stages of endodontic therapy, and various techniques have been applied for it. The present study was conducted to compare the quantity of debris extruded from the apical foramen during canal preparation during the manual technique and with the use of three rotary systems (Profile, Race, FlexMaster). One hundred single-rooted premolars were divided into four groups of 25 teeth each. For collection of debris, vials containing distilled water and weighed before canal preparation were used. Groups H, P, R and F were prepared by the manual step-back technique, and with the use of the Profile system, Race system and FlexMaster system, respectively. After canal preparation, the vials were dried thoroughly and reweighed. The difference between the weights of the vials at the two stages was taken as the debris weight. The mean debris weights were compared by one-way ANOVA. Group H had the highest mean debris weight, which was significantly different from those of the rotary groups (P < 0.001). The lowest mean debris weight was related to group R, which was significantly different from that of group F but not significantly different from that of group P. It was concluded that the Race system induces less extruded debris than the manual technique and the FlexMaster system.

PMID: 16858137 [PubMed - indexed for MEDLINE]

Endodontic therapy.

J Am Dent Assoc. 2006 Jun;137(6):722, 724; author reply 724, 726

Authors: Kolzet DJ

PMID: 16803799 [PubMed - indexed for MEDLINE]

Analysis of the sealing ability of different obturation techniques in oval-shaped canals: a study using a bacterial leakage model.

Braz Oral Res. 2006 Jan-Mar;20(1):64-9

Authors: De Deus G, Murad CF, Reis CM, Gurgel-Filho E, Coutinho Filho T

The aim of this study was to evaluate the sealing ability of 3 obturation techniques in oval canals using a bacterial leakage model. Seventy mandibular incisors with oval canals were selected after buccolingual and mesiodistal radiographs, and divided into three groups. After instrumentation, the canals were obturated respectively by lateral condensation (G1), warm vertical condensation (G2) and Thermafil (G3). Five root canals were not obturated and served as positive controls; five teeth with intact crowns served as negative controls. All teeth were mounted on a 2 chamber apparatus and then exposed to human saliva. The number of days required for the entire contamination of the root canals was recorded, observing the turbidity of the BHI broth, for a period of 100 days. 84.21% of the samples from the lateral condensation group (G1); 84.21% of the samples from the warm vertical condensation group (G2); and 89.47% of the samples from the Thermafil System group (G3) showed no contamination at the end of the study. No statistical significant difference was found among the three techniques. The quality of the apical seal in the three techniques tested was similar.

PMID: 16729177 [PubMed - indexed for MEDLINE]

The influence of the surgical operating microscope in locating the mesiolingual canal orifice: a laboratory analysis.

Braz Oral Res. 2006 Jan-Mar;20(1):59-63

Authors: Coutinho Filho T, La Cerda RS, Gurgel Filho ED, de Deus GA, Magalh&#xE3;es KM

The aim of this study was to evaluate the influence of using the surgical operating microscope (SOM) for detection of the mesiolingual (ML) canal orifice in extracted first maxillary permanent molars. One hundred and eight human first maxillary permanent molars were randomly selected and mounted onto a dental chair mannequin. Conventional access cavity was prepared and an attempt was made to locate the mesiolingual canal orifice using only a sharp explorer, a mirror and a #10 K-file. A mesiolingual canal orifice was either located or not located. If not located, the teeth were then evaluated by using a surgical operating microscope (SOM). The mesiobuccal roots of all teeth where the ML canal orifice had not been located were sectioned in an axial plane and the sections were explored with an adjunctive use of the SOM at a 25 X magnification. ML canal orifices were detected in 58 teeth using only a sharp explorer, a mirror and #10 K-file. In the remaining 50 teeth, 37 ML canal orifices were located by using the SOM and 3 ML canal orifices were located after root sectioning. In 10 teeth, the ML canal orifices were not found. The results of this study showed a high incidence of a ML canal in the mesiobuccal roots of the first maxillary molars (90.7%) and demonstrated that the adjunctive use of the SOM increased the ability of the dental clinician to locate the ML canal orifice.

PMID: 16729176 [PubMed - indexed for MEDLINE]

NSK reciprocating handpiece: in vitro comparative analysis of dentinal removal during root canal preparation by different operators.

Braz Dent J. 2006;17(1):10-4

Authors: Wagner MH, Barletta FB, Reis Mde S, Mello LL, Ferreira R, Fernandes AL

The purpose of this study was to assess dentin removal during root canal preparation by different operators using a NSK reciprocating handpiece. Eighty-four human single-rooted mandibular premolars were hand instrumented using Triple-Flex stainless-steel files (Kerr) up to #30, weighed in analytical balance and randomly assigned to 4 groups (n=21). All specimens were mechanically prepared at the working length with #35 to #45 Triple-Flex files (Kerr) coupled to a NSK (TEP-E10R, Nakanishi Inc.) reciprocating handpiece powered by an electric motor (Endo Plus; VK Driller). Groups 1 to 4 were prepared by a professor of Endodontics, an endodontist, a third-year dental student and a general dentist, respectively. Teeth were reweighed after root canal preparation. The difference between weights was calculated and the means of dentin removal in each group were analyzed statistically by ANOVA and Tukey's test at 5 % significance level. The greatest amount of dentin removal was found in group 4, followed by groups 2, 3 and 1. Group 4 differed statistically from the other groups regarding dentin removal means [p<0.001 (group 1); p=0.005 (group 2); and p=0.001 (group 3)]. No statistically significant difference was found between groups 1 and 2 (p=0.608), 1 and 3 (p=0.914) and 2 and 3 (p=0.938). In conclusion, although the group prepared by a general dentist differed statistically from the other groups in terms of amount of dentin removal, this difference was clinically irrelevant. The NSK reciprocating handpiece powered by an electric engine was proved an effective auxiliary tool in root canal preparation, regardless of the operator's skills.

PMID: 16721457 [PubMed - indexed for MEDLINE]

The importance of apical patency and cleaning of the apical foramen on root canal preparation.

Braz Dent J. 2006;17(1):6-9

Authors: Souza RA

The apical limit of root canal instrumentation has always been a matter of great controversy. Despite the large number of published studies on this subject, a consensus has not yet been reached. In fact, the recent discussion on apical patency and cleaning of the apical foramen, as well as the incorporation of these procedures to the endodontic treatment, seem to have raised even more polemics. It is likely that all this polemics has its roots in the lack of interrelation between the theoretical knowledge of pulp stump and periapical tissues and the real clinical practice. By addressing the most important aspects of this theme, this paper aims to present news concepts about the importance of apical patency and cleaning of the apical foramen during root canal preparation.

PMID: 16721456 [PubMed - indexed for MEDLINE]

Shock of paradigms on the instrumentation of curved root canals.

Braz Dent J. 2006;17(1):3-5

Authors: P&#xE9;cora JD, Capelli A

This paper makes a practical analysis about the paradigm on the instrumentation of curved root canals. In Endodontics, a paradigm has been created. Theories and techniques for instrumentation of curved root canals state that the use of a #25 file in the apical portion fulfills all the requirements for cleaning and shaping of the root canal system. Every scientific theory or paradigm should be continuously opened to modifications or refutation. The existence of extremely flexible instruments fabricated from metal alloys, methods for accurate determination of the real anatomic diameter and achievement of optimal shaping and cleaning of the apical portion created new theories and a new paradigm on the instrumentation of curved root canals. Therefore, this new insight will gradually modify the mentality of researchers and clinicians, but will still be open to further investigations and theories.

PMID: 16721455 [PubMed - indexed for MEDLINE]

[A study on the accuracy of electronic root canal length measurement and its influential factors]

Shanghai Kou Qiang Yi Xue. 2006 Apr;15(2):140-2

Authors: Lu YM, Qin JN, Cao DJ

PURPOSE: To study the accuracy of JUSTY-II electronic apex locator and the influential factors on the accuracy of root canal working length measurement. METHODS: 148 teeth, including 71 teeth with pulpitis, 46 with necrotic pulp and 31 with apical periodontitis, were divided into two groups in random. The accuracy of electronic root canal working length measurement group was compared with that of the manual measurement group by Chi(2) test. The influence of clinical types, root canal in dry or moisture conditions and root canal preparation on the accuracy of root canal working length measurement was analyzed. RESULTS: The accuracy of electronic apex locator was 87.84%, while it was 43.24% in manual measurement, the difference was significant (P<0.01). The accuracy in the group of apical periodontitis was significantly lower than that of the other groups (P<0.05). Root canal in dry or moisture conditions had no effect on the accuracy of root canal length measurement, but root canal preparation could decrease the accuracy of measurement (P<0.05). CONCLUSION: Electronic apex locator is an accurate and convenient device in measurement of root canal working length. Apical periodontitis and root canal preparation can decrease the accuracy of measurement.

PMID: 16685352 [PubMed - in process]

Impact of endodontic treatments on the rigidity of the root.

J Dent Res. 2006 Apr;85(4):364-8

Authors: Lang H, Korkmaz Y, Schneider K, Raab WH

The destabilizing effect of endodontic treatment upon teeth is still controversial. The purpose of this study was to investigate the effects of different steps of endodontic treatments upon the rigidity of teeth. Extracted untreated central maxillary anterior teeth were loaded (3.75 N), and deformations of the root were assessed by Speckle pattern interferometry. The following treatments (with subsequent determination of deformability) were conducted sequentially: access preparation, manual instrumentation (Kerr files ISO-40, ISO-60, ISO-80, ISO-110), and tapered and parallel-sided post preparation. It was found that the teeth were increasingly destabilized by any treatment. While the increased deformability was not significant with the manual enlargement (p > 0.05), we found a significant destabilization after access preparation and post preparation (p < 0.05). A corresponding difference was found after conversion of the post preparation from tapered to parallel-sided (p < 0.05). Both substance loss and modifications of the natural root canal geometry play an important role in tooth rigidity.

PMID: 16567560 [PubMed - indexed for MEDLINE]

[Scanning electron microscopic study on the use of traditional Chinese medical irrigant in ultrasonic root canal instrumentation]

Shanghai Kou Qiang Yi Xue. 2006 Feb;15(1):77-80

Authors: Wang Q, Xiong SJ, Lin XJ, Liu GX

PURPOSE: To evaluate the cleaning ability of traditional Chinese medicine Jieeryin used as ultrasonic root canal irrigant. METHODS: A total of 20 extracted human single-rooted teeth were divided into 4 groups: normal saline, 3.33% Jieeryin, 30% Jieeryin and 2.5% sodium hypochlorite. After ultrasonic root canal preparation a 15#-K type ultrasonic file was inserted into the root canal without contacting the root canal wall and the ultrasonic irrigation was kept for 10 seconds. The cleaning of the cervical, middle and apical thirds of the root canal walls was evaluated by scanning electron microscope. The data were analyzed statistically by ANOVA and Bonferroni test. RESULTS: The cleaning ability of 30% Jieeryin was similar to that of 2.5% NaClO (P>0.05) in the cervical third, and it was significantly better than 3.33% Jieeryin (P<0.01) and normal saline (P<0.05). There was significant difference between the cervical third and the middle or apical thirds (P<0.01) of 30% Jieeryin. There was no significant difference between the four groups in the middle third (P>0.05). In the apical third, 2.5% NaClO was significantly better than normal saline (P>0.05). No significant difference was found between 3.33% Jieeryin and saline in all thirds. CONCLUSION: Cleaning by 30% Jieeryin or 2.5% NaClO with ultrasonic technique was superior compared to the cleaning by 3.33% Jieeryin or normal saline in the cervical third.

PMID: 16525616 [PubMed - in process]

Anatomical redesign for the treatment of dens invaginatus type III with open apexes: a literature review and case presentation.

J Am Dent Assoc. 2006 Feb;137(2):180-5

Authors: Silberman A, Cohenca N, Simon JH

BACKGROUND: Dens invaginatus is a rare dental anomaly that may give rise to many complex anatomical forms. The complexity of the internal anatomy may create challenges for the complete removal of the diseased pulpal tissue and the subsequent sealing of the canal system. CASE DESCRIPTION: The authors discuss the modification of the internal anatomy under the operating microscope, allowing the clinician better access to treat predictably the canal system with conventional or alternative techniques. CONCLUSION AND CLINICAL IMPLICATIONS: Considering the anatomical variations and the challenges that a dens invaginatus may present, a practitioner may consider a modification of the internal anatomy of the canal system to gain better access for proper instrumentation, disinfection and sealing of the root canal system using conventional or contemporary techniques.

PMID: 16521383 [PubMed - indexed for MEDLINE]

Effect of the sodium hypochlorite and citric acid association on smear layer removal of primary molars.

Braz Oral Res. 2005 Oct-Dec;19(4):261-6

Authors: G&#xF6;tze Gda R, Cunha CB, Primo LS, Maia LC

This study aimed to assess the capacity of a sodium hypochlorite and citric acid (CA) association (the latter at different concentrations) in removing coronal smear layer (SL) of primary teeth. For this purpose, the pulp chamber roof and floor of 28 primary molars were removed to obtain enamel and dentine disks. SL was produced on the internal walls of the disks using high-speed drills. The disks were irrigated with 1% sodium hypochlorite and citric acid at different concentrations (CA-4%, CA-6%, CA-8% and CA-10%), and with 0.9% sodium chloride. The samples were split and observed under SEM. Scores were attributed to the obtained photomicrographs, according to the amount of SL present. It was noted that all the tested concentrations of citric acid used after the sodium hypochlorite were capable of removing SL. The results were analyzed by the Kruskal-Wallis test, and there was no significant statistical difference among the scores of the groups tested. However, it was observed that CA-8% and CA-10% caused peritubular dentine destruction, and that CA-4% presented a larger number of samples with dense SL. Based on these results, 6.0% citric acid in association with 1% sodium hypochlorite is suggested as auxiliary chemical substances for primary teeth irrigation.

PMID: 16491253 [PubMed - indexed for MEDLINE]

Evaluation of the smear layer removal effectiveness of EDTA using two techniques: an SEM study.

J Contemp Dent Pract. 2006 Feb 15;7(1):9-16

Authors: Tinaz AC, Karadag LS, Alaçam T, Mihçioglu T

Obtaining the cleanest canal possible before obturation is one of the goals of endodontic treatment. The purpose of this study was to compare the smear layer removal capability of ethylenediamine tetra-acetic acid (EDTA) application with passive ultrasonic and cotton wrapped on reamer activation. Twelve extracted human teeth with single root canals were used for the study. They were conventionally hand instrumented using reamers and K files. The apical aspect of the canals was enlarged to a #40 file. The teeth were divided into 4 four groups, instrumented and irrigated as follows: Group-A EDTA agitated at the end of preparation with cotton wrapped on a reamer for 1 min; Group-B EDTA applied with ultrasonic agitation for 1 min; Group-C irrigated with EDTA+sodium hypochlorite (NaOCl) (negative control group); and Group-D irrigated with distilled water (positive control group). After scanning electron microscopic study at three different levels, smear layer and dentinal tubules were scored. Means were tested for significance using the Z test. When the techniques were compared, the cotton wrapped on reamer agitation method was as successful as the ultrasonic activation of the files. Although all groups had significantly higher smear layer scores at apical compared to coronal sections, no significant differences were recorded.

PMID: 16491143 [PubMed - indexed for MEDLINE]

Inability of laser and rotary instrumentation to eliminate root canal infection.

J Am Dent Assoc. 2006 Jan;137(1):67-70

Authors: Jha D, Guerrero A, Ngo T, Helfer A, Hasselgren G

BACKGROUND: The authors evaluated the antibacterial effectiveness of laser instrumentation and rotary instrumentation of anterior, single-rooted teeth infected with Enterococcus faecalis. METHODS: The authors divided 35 infected samples into five groups: Group A: inoculation, laser, 17 percent ethylene-diamine-tetra-acetate (EDTA), 2.5 percent sodium hypochlorite (NaOCl) (n=10); Group B: inoculation, laser, 17 percent EDTA, sterile saline (n = 10); Group C: inoculation, rotary, 17 percent EDTA, 2.5 percent NaOCl (n=10); Group D: inoculation, no instrumentation (positive control) (n=5); Group E: no inoculation, no instrumentation (negative control) (n=5). They sampled and incubated dentin shavings from each canal for bacterial growth. RESULTS: In Group A, eight tubes were positive for bacterial growth. In Group B, 10 tubes were positive for bacterial growth. In Group C, six tube were positive for bacterial growth. In Group D, all of the tubes were positive for bacterial growth. In Group E, no tubes showed bacterial growth. The Fisher exact test showed no significant differences among groups A, E and C. CONCLUSION: Neither the laser nor the rotary instrumentation was able to eliminate endodontic infection. CLINICAL IMPLICATIONS: Although lasers have been presented as high-tech tools for disinfecting root canals, the laser was ineffective in this study.

PMID: 16457001 [PubMed - indexed for MEDLINE]

Blood cell attachment to root surfaces treated with EDTA gel.

Braz Oral Res. 2005 Apr-Jun;19(2):88-92

Authors: Leite FR, Moreira CS, Theodoro LH, Sampaio JE

Root debridement generates a smear layer which contains microorganisms and toxins that could interfere in periodontal healing. For this reason, different substances have been used to remove it and to expose collagen fibers at the tooth surface. Blood element adhesion to demineralized roots and clot stabilization by collagen fibers are extremely important for the success of periodontal surgery. The aim of this study was to evaluate the different patterns of blood element adsorption and adhesion to root surfaces only irrigated with distilled water and after application of a manipulated or an industrialized EDTA gel. Thirty samples were planed, equally divided into three groups and treated with distilled water (control), a manipulated EDTA gel or an industrialized one. Immediately after, samples were exposed to fresh blood and prepared for scanning electron microscopy. Untreated planed dentin presented the best results with blood cells entrapped in a thick web of fibrin. In the manipulated EDTA group, the web of fibrin was thick with sparse blood elements. The worst result was seen with the industrialized EDTA group, in which no blood elements could be seen. Statistical difference was obtained between control and industrialized EDTA groups. Surfaces only irrigated presented the most organized fibrin network and cell entrapment.

PMID: 16292439 [PubMed - indexed for MEDLINE]

[The mechanic retention of the casting post with keeper in magnetic retentor overdenture]

Shanghai Kou Qiang Yi Xue. 2005 Oct;14(5):525-7

Authors: Xu K, Sun J, Huang QF, Chen R, Gu JL, Zhang XY

PURPOSE: To reduce the cost of the fabrication of the magnetic retentor,and meet the clinical requirements, nonprecious alloy such as Co-Cr alloy was used to fabricate the magnetic retentor in overdenture , instead of the precious alloy. METHODS: A mandibular canine was chosen for root canal preparation in vitro. Thirty two resin posts were made in the same root canal with self-curing resin. The 32 resin posts were randomly divided into 4 groups. Among them,2 groups were fabricated with soft Co-Cr alloy, gold alloy(55.6%Au) respectively in vitro. Another 2 groups were fabricated with Co-Cr alloy, and the surface of the root casting post with keeper were treated with gold deposit and gold coating technique. After that, test of dislodgment force was done and one-way ANOVA was performed with SAS 6.2 software package. RESULTS: The dislodgment force of the root casting posts with keeper which were fabricated with the Co-Cr, Ni-Cr, and gold alloy had significant difference(P<0.01). While after surface treatment by gold deposit and gold coating technique on root casting posts with keeper that were fabricated with Co-Cr and Ni-Cr alloy, there was no significant difference in dislodgment force, compared with that of gold alloy. CONCLUSIONS: After surface treatment of the root casting posts with keeper which were fabricated with the Co-Cr and Ni-Cr alloy, the same clinical retentive effect can be obtained as the one that was fabricated with gold alloy.

PMID: 16288336 [PubMed - in process]

Effects of autoclaving on dimensional qualities and physical properties (flexural rigidity and brittleness) of newly developed root canal filling point made of polypropylene (FLEX POINT NEO).

Bull Tokyo Dent Coll. 2005 May;46(1-2):27-32

Authors: Ohne M, Yamazaki Y

In this study, we investigated the effects of 10 cycles of conventional autoclaving (121 degrees C, 20 min) on the dimensional integrity and physical properties (flexural rigidity and brittleness) of a newly developed root canal filling point made of polypropylene (FLEX POINT NEO). We measured the diameters of autoclave-sterilized and non-treated polypropylene points (020 through 070) and calculated the incidence of deviation from ISO specifications (6877.4.4.1, 1995). In order to ascertain physical properties, we tested autoclave-sterilized and non-treated polypropylene points (030, 050 and 070) for flexural rigidity. This was done by evaluating deflection value when a load was placed at the free tip-end of the point and brittleness in accordance with ISO specifications (6877.6.5.2). Ten cycles of autoclaving showed no significant effect on the diameters of the polypropylene points. All the polypropylene points in both the non-treated and the autoclave-sterilized groups met ISO specifications in terms of dimensional integrity of diameter. In the autoclave-sterilized group, 030 and 050 polypropylene points showed a slight decrease in flexural rigidity (3.4% in 030, 10.0% in 050). In terms of brittleness, none of polypropylene points showed any sign of fracture.

PMID: 16285601 [PubMed - indexed for MEDLINE]

Microbial leakage of Cavit, IRM, and Temp Bond in post-prepared root canals using two methods of gutta-percha removal: an in vitro study.

J Contemp Dent Pract. 2005 Aug 15;6(3):53-61

Authors: Balto H, Al-Nazhan S, Al-Mansour K, Al-Otaibi M, Siddiqu Y

The aim of this study was to evaluate the integrity of the coronal seal of Temp-Bond and compare it to Cavit and IRM after post space preparation using S. faecalis as a microbial tracer. In addition, the affect of two methods of gutta percha removal on the apical seal of root canal fillings was also evaluated. Forty extracted human single rooted teeth were prepared chemomechanically and obturated with gutta percha and AH26 sealer cement using the lateral cold condensation technique to a standardized working length of 15 mm. About 10 mm of the coronal gutta-percha was removed with either Peeso-reamer or a hot plugger. The roots were divided into three experimental groups of 10 roots and a control group. Each experimental group was subdivided equally into two groups of 15 each according to the method of post space preparation. Cavit, IRM, and Temp-Bond were used to seal the access opening. Each root was fixed in a cuvette containing Tryptic Soya Broth which, covered 2 mm of the root apex. Bacterial suspension was introduced through pipette. Fresh bacterial suspension was added every week, and the system was monitored daily for the growth of microorganisms for a period of one month. The results showed there was no significant difference in terms of coronal leakage between the three coronal materials used (P=0.478), but the methods of gutta-percha removal did have an impact on the apical leakage (P=0.047). The mean value showed the Peeso-reamer provided less leakage compared to using a hot plugger during the 30-day experimental time period. It was concluded the temporary type of coronal seal of endodontically treated teeth will not prevent coronal leakage if left for a long period of time. In addition, permanent cementation of the post with the coronal restoration should be carried out as soon as possible to prevent recontamination of the root canal.

PMID: 16127472 [PubMed - indexed for MEDLINE]

Influence of cervical preflaring on determination of apical file size in maxillary premolars: SEM analysis.

Braz Dent J. 2005;16(1):30-4

Authors: Barroso JM, Guerisoli DM, Capelli A, Saquy PC, P&#xE9;cora JD

The purpose of this study was to investigate the influence of cervical preflaring on the determination of the first file that binds at working length (WL) in buccal roots of maxillary premolars. Five groups (n=10) were formed at random and, after standard access cavities, the WL was determined 1 mm short from the apex. In group 1, the initial apical file was inserted without preflaring of cervical and middle thirds of the root canals. In groups 2 to 5, the cervical and middle thirds were enlarged with sizes 90 and 110 Gates-Glidden drills, K(3) Orifice Opener instruments, ProTaper instruments and LA Axxess burs, respectively. Canals were sized manually with K-files, starting with No. 08 K-files inserted passively up to the WL. File sizes were increased until a binding sensation was felt at the WL and the size of the instrument was recorded. Transversal sections of the WL regions were examined under scanning electron microscopy and the discrepancies between the canal diameter and first file to bind at the WL were assessed. Significant differences (p<0.001) were found between the groups. The major discrepancy was found without preflaring (mean 157.8 microm). LA Axxess burs produced the smallest discrepancy (mean 0.8 microm). Gates-Glidden drills and K(3) Orifice Opener instruments showed no significant differences (p>0.05) between their results (83.2 microm and 73.6 microm, respectively). The discrepancy for ProTaper instruments was 35.4 microm on average. In conclusion, the instrument binding technique for determination of the anatomical diameter at the WL was not precise. Preflaring of the cervical and middle thirds improved the determination of the anatomical diameter at the WL, and the type of instrument played a major role. Canals preflared with LA Axxess burs showed a more accurate binding of the files to anatomical diameter.

PMID: 16113930 [PubMed - indexed for MEDLINE]

[Nursing of root canal therapy with nickel titanium mechanical instruments]

Shanghai Kou Qiang Yi Xue. 2005 Apr;14(2):194-6

Authors: Lan WH, Xiao Y, Zheng CS, Liu P, Zhu MY

PURPOSE: To discuss the related problems of nursing during root canal preparation with nickel titanium mechanical instruments. METHODS: 206 cases were nursed who underwent root canal preparation, after which the dentists and patients were surveyed on their satisfactory extents, in order to assess the effect of nursing. RESULTS: The results of root canal preparation of 206 cases were good without any accidents such as break of instruments, while 100% dentists and 97.58% patients were satisfied with the nursing. CONCLUSION: Proper and skilled nursing could shorten treatment time, enhance patients' compliableness and decrease the unnecessary injuries. Thus it raised the efficiency and therapeutic effect.

PMID: 15886849 [PubMed - in process]

The clinical significance and management of apical accessory canals in maxillary central incisors.

J Am Dent Assoc. 2005 Mar;136(3):331-5; quiz 379-81

Authors: Iqbal MK, Gartenberg J, Kratchman SI, Karabucak B, Bui B

BACKGROUND: The maxillary central incisor is considered to be the least difficult subject for a clinical endodontic experience. However, the internal anatomy of maxillary central incisors can present a number of variations, including multiple accessory canals. CASE DESCRIPTION: This article highlights the clinical significance and management of accessory canals located in the apical one-third of maxillary central incisors. The authors present two case reports in which failure to detect the accessory canals led to root canal failure and subsequent surgical intervention. Another two case reports present the serendipitous discovery and nonsurgical management of accessory canals during the initial treatment of maxillary incisors. CONCLUSIONS AND CLINICAL IMPLICATIONS: It is important for the clinician to be able to detect the signs suggesting the presence of accessory canals in maxillary central incisors. Failure to do so may lead to a less-than-optimal endodontic treatment outcome.

PMID: 15819346 [PubMed - indexed for MEDLINE]

In vitro evaluation of the thermal alterations on the root surface during preparation with different Ni-Ti rotary instruments.

Braz Dent J. 2004;15(2):115-8

Authors: Capelli A, Guerisoli DM, Barbin EL, Span&#xF3; JC, Pécora JD

The present study evaluated, in vitro, the temperature alterations on the external root surface during instrumentation with four different rotary systems. A total of 20 extracted human maxillary lateral incisors were instrumented using either the ProFile, MicroMega, Quantec or K3 systems and the thermal alterations on the root surface were recorded by means of three thermocouples attached to the coronal, middle and apical portions of the root. Mean temperature increases no higher than 0.4 degrees C +/- 1.0 degrees C (ProFile system) were recorded, which indicates that these instruments are safe for the surrounding periodontal tissues.

PMID: 15776193 [PubMed - indexed for MEDLINE]

Histological study of the effect of some irrigating solutions on bacterial endotoxin in dogs.

Braz Dent J. 2004;15(2):109-14

Authors: Silva LA, Leonardo MR, Assed S, Tanomaru Filho M

The aim of this study was to evaluate, histopathologically, the effectiveness of mechanical preparation of root canals using different irrigating solutions in dog teeth filled with LPS after pulpectomy. A total of 120 root canals of 6 mongrel dogs were filled with a solution of LPS after pulpectomy. The irrigating solutions used were saline, 1, 2.5, and 5% sodium hypochlorite, and 2% chlorhexidine. No irrigation was used in the control group. The animals were sacrificed after 60 days and the teeth were fixed and demineralized. Subsequently, serial 6-microm sections were stained with hematoxylin and eosin and Mallory's trichrome for histopathological analysis and Brown-Brenn for verification of bacterial contamination. Analysis showed that the inflammatory infiltrate was statistically less intense in the groups in which the root canals were irrigated with 5% sodium hypochlorite and 2% chlorhexidine. However, none of the irrigating solutions completely inactivated the harmful effects of LPS. Mechanical preparation associated with different irrigating solutions did not completely inactivate LPS.

PMID: 15776192 [PubMed - indexed for MEDLINE]

[Clinical evaluation of Nickel-titanium rotary instruments Hero 642 in root canal preparation]

Shanghai Kou Qiang Yi Xue. 2005 Feb;14(1):2-5

Authors: Xu Q, Lin JQ, Chen H, Wei X

PURPOSE: This research is aimed to assess the clinical value of the Nickel-titanium (NiTi) rotary instruments Hero 642 in root canal preparation. METHODS: 60 molars were instrumented by Hero 642 rotary instruments using crown-down technique in the experimental group, and by K files using step-back technique in the control group. All teeth were obturated with lateral condensation method. The efficiency of preparation and obturation was analyzed by radiographs before and after treatment. The canal curvature and operation time were compared by means of Student's t test, and the incidence of complications and post-treatment pain were compared by means of Chi square test between two groups. RESULTS: No transportation, apical blockage, ledge or perforation was found in the experimental group. The Hero 642 instruments could keep the original curvature and flow of the root canals. There was more canal complications in the control group than in the experimental group (P<0.005). The operative time was shorter and post treatment pain seldom occurred in the experimental group. CONCLUSION: The NiTi rotary instruments Hero 642 can be used for preparation of root canals effectively and safely, and is worth wide application.

PMID: 15747003 [PubMed - in process]

The effectiveness of three instrumentation techniques on the elimination of Enterococcus faecalis from a root canal: an in vitro study.

J Contemp Dent Pract. 2005 Feb 15;6(1):94-106

Authors: Colak M, Evcil S, Bayindir YZ, Yigit N

The in vitro reduction of a bacterial population in a root canal by mechanical instrumentation using three techniques was evaluated. Root canals inoculated with a Enterococcus faecalis (E. faecalis) suspension were instrumented using hand Hedstroem files, Giromatic files, and Hero 642 rotary instruments. Irrigation was performed using sterile saline solution. Root canals were sampled before and after instrumentation. After serial dilutions, samples were plated onto Mitis-Salivarius agar and the colony forming units grown were counted. All instruments tested were able to significantly reduce the number of bacterial cells in the root canal, however, the results of this study indicated that Hedstroem files, Giromatic, and Hero 642 techniques were not significantly different in their ability to reduce intracanal bacteria.

PMID: 15719081 [PubMed - indexed for MEDLINE]

A modified hemostat for endodontic instruments.

J Am Dent Assoc. 2005 Jan;136(1):80

Authors: Zuckerman GR

PMID: 15693501 [PubMed - indexed for MEDLINE]

[Comparison of the clinical effects of three root canal treatments.]

Shanghai Kou Qiang Yi Xue. 2004 Oct;13(5):459-61

Authors: Zheng QZ, Wang J, Liu LM

PURPOSE: To compare the clinical effects of three root canal treatments. METHODS: The patients were randomly divided into A,B,C groups. Group A: profile preparation of the root canal, then the root canal was filled with maillefer thermafil. Group B: profile preparation of the root canal, iodoform cataplasm and gutta percha point was used to fill root canal. Group C: preparation of the root canal with stainless steel hand-operated root canal magnified instrument, iodoform cataplasm and gutta percha point was used to fill the root canal. RESULTS: Through X ray and clinical evaluation, the root canal therapy result in group A was superior to group B, group B was superior to group C. CONCLUSION: The work efficiency of preparative instrument of profile flexible nickel-titanium root canal is high. The successful rate of maillefer thermafil for results root canal therapy is superior to the other methods. Root canal preparation by profile can get satisfying effects.

PMID: 15514884 [PubMed - in process]

The impact of post space preparation with Gates-Glidden drills on residual dentin thickness in distal roots of mandibular molars.

J Am Dent Assoc. 2004 Jul;135(7):903-9

Authors: Kuttler S, McLean A, Dorn S, Fischzang A

BACKGROUND: Posts frequently are used to retain buildups. The authors examined the effects of post space preparation with Gates-Glidden drills on residual dentin thickness in distal roots of mandibular molars. METHODS: The authors embedded 26 root-treated mandibular molars in endodontic cubes and sectioned them perpendicularly to their long axis at 1.8-millimeter intervals. They placed Gates-Glidden drills nos. 3, 4, 5 and 6 sequentially to 5 mm short of working length in the distal canals. After using each drill size, the authors measured the dentin thickness from light microscopic images of the tooth slices. RESULTS: The authors analyzed data to detect changes resulting from canal instrumentation. They performed statistical analysis by partitioning the variability in a nested analysis of variance. Strip perforations occurred with a no. 4 Gates-Glidden drill 7.3 percent of the time and more frequently with larger drills. After endodontic treatment alone, the canal wall on the furcal side was less than 1 mm thick 82 percent of the time and less than 0.5 mm thick 17.5 percent of the time. CONCLUSIONS: Dentin thickness correlates inversely to post space diameter. A no. 4 Gates-Glidden drill caused strip perforations in 7.3 percent of the canals studied, and therefore the authors recommend that Gates-Glidden drills larger than a no. 3 not be used in these roots. After endodontic treatment, the furcation-side dentin thickness was less than 1 mm in 82 percent of the teeth. CLINICAL IMPLICATIONS: Post space preparation in mandibular molars carries significant risk of perforation. Post space in such teeth should be limited to the endodontically prepared canal.

PMID: 15354901 [PubMed - indexed for MEDLINE]

[Effect of tinidazole-dexamethasone-iodoform paste on controlling endodontic interappointment emergencies]

Shanghai Kou Qiang Yi Xue. 2004 Jun;13(3):222-3

Authors: Wang HH, Huang LJ

PURPOSE: To compare the clinical effect of tinidazole-dexamethasone-iodoform paste on intracanal dressing medication for teeth with chronic periapical periodontitis with that of formocresol. METHODS: 520 permanent teeth with chronic periapical periodontitis were selected and divided randomly into tinidazole-dexamethasone-iodoform paste group (A group) and formocresol group (B group). The periapical signs and symptoms were recorded, radiographs were taken. After root canal preparation, the tinidazole-dexamethasone-iodoform paste was used as an intracanal dressing medication for one week in A group and the formocresol paper point was used in B group. During the course of canal treatment, the clinical findings were assessed with clinical periapical index (CPI), the cases were followed up for two years. RESULTS: There was significant difference between A and B group (P<0.01), group A was better than group B. There was no significant difference between two groups of the success rate after following up two years (P>0.05). CONCLUSION: As an intra-canal sterilization medication,tinidazole-dexamethasone-iodoform can reduce the occurrence of endodontic interappointment emergencies in teeth with chronic periapical periodontitis and has a good long-term result.

PMID: 15269867 [PubMed - indexed for MEDLINE]

[Effect of ultrasonic in instrumentation on curved and obstructed root canal preparation]

Shanghai Kou Qiang Yi Xue. 2004 Jun;13(3):217-8

Authors: Li XF, Fang QP, Wang WQ, Wang RF

PURPOSE: To investigate and evaluate the effect of ultrasonic instrumentation on curved and obstructed root canal preparation. METHODS: Ultrasonic preparation was used on 117 root canals of 92 teeth due to resinifying therapy, pulp mummification and aging which could not be reopened and treated with traditional methods. RESULTS: 108 canals were successfully reopened with a successful rate of 92.3%. Failure occurred in 9 cases. 2 of them were lateral perforation. 2 were obstructed on curving position. 2 of them were due to pulp calcification in older patients. 3 were failing after resinifying therapy. CONCLUSION: The ultrasonic treatment of root canal was an effective and safe method. It was still limited in a cases with pulp calcification and some fine root canals treated by resinifying therapy.

PMID: 15269865 [PubMed - indexed for MEDLINE]

[The effect of coronal preflaring on the working length measurement of root canals in molars]

Shanghai Kou Qiang Yi Xue. 2004 Jun;13(3):179-81

Authors: Wang Q, Xiong SJ, Dou HQ, Zhou RE

PURPOSE: To study the influence of coronal preflaring of root canal on the working length measurement in molars. METHODS: 48 molars from 47 adult patients with pulpitis were divided into two groups randomly. 74 root canals of 24 molars were examined in Group 1. After preparing an access cavity, the root canal orifices were located. A 15# K-type file was inserted into root canal to detect resistance at the apical region. 75 root canals of 24 molars were examined in Group 2. Before testing the apical resistance,a size 25# and 20# ProFile.06 taper NiTi rotary instrument was used to enlarge the canal orifice and flare the coronal portion of the root canal. After placing 15# K-type files, a radiograph was taken with the bisecting-angle technique. The distance between the tip of the file and the radiographic apex was measured on the radiographs. Statistical analysis of univariate and multiple logistic regression were carried out for analysis. RESULTS: There was a significant difference between the two groups (P<0.05), there were more accurate measurements in Group 2 than in Group 1. No statistical correlation was found between X-ray measurements and age, sex and the position of molars,while there was significant correlation between maxillary molars and mandibular molars (P<0.05). CONCLUSION: Preflaring the coronal portion of the root canals could significantly increase the accurate measurements of the working length of root canals in molars.

PMID: 15269853 [PubMed - indexed for MEDLINE]

Assessment of morphological changes and permeability of apical dentin surfaces induced by Nd:Yag laser irradiation through retrograde cavity surfaces.

J Contemp Dent Pract. 2004 May 15;5(2):102-13

Authors: Arisu HD, Bala O, Alimzhanova G, T&#xFC;rköz E

The purpose of this in vitro study was to observe the morphological changes and apical dye penetration at apical dentin surfaces induced by Nd:YAG laser irradiation at different power settings with and without a laser initiator. Seventy five single rooted human maxillary anterior teeth were used. Following the establishment of the working lengths, the root canals were enlarged with step-back technique. The apex of each root was resected 3 mm perpendicular to its long axis. Standard Class I cavities of 2 mm depth and 2 mm width were prepared. The teeth were randomly divided into five groups with fifteen teeth in each. In Group 1, the retrograde cavity preparations were lased with Nd:YAG laser at 2 W and those in Group 2 preparations were lased with Nd:YAG laser at 3.2 W. In Group 3, the retrograde cavity surfaces were lased with Nd:YAG laser at 2 W following the application of India ink. Group 4 was lased with the same settings of Group 2 after an absorbent cotton point soaked with India ink was inserted into the cut dentinal surfaces and the inner walls of the apical preparations. Group 5 served as control. Five teeth from each group were examined using scanning electron microscopy (SEM). The amounts of smear layer, debris, and recrystalized dentin present were assessed and scored. Retrograde cavities of ten teeth from each group were filled with amalgam to examine apical dye penetration. The teeth were immersed in 2% basic fuscin and kept for 48 hours. Dye penetration was evaluated by stereomicroscope at a magnification of X10. The results showed the usage of India ink with Nd:YAG laser enhanced the amount of melting and recrystalization of dentin and the radiation and initiator increased the leakage.

PMID: 15150638 [PubMed - indexed for MEDLINE]

[Advances in investigation of calcified root canal therapy]

Shanghai Kou Qiang Yi Xue. 2004 Apr;13(2):141-3

Authors: Huang YF, Zhu YQ

Calcified root canal occurs often during root canal therapy. It's important to understand various methods to deal with calcified root canal, which may increase the successful rate. From anatomy, radiography, chemical root canal preparation, ultrasonic root canal preparation and endodontic microscopic system etc., this paper reviews the present research about the treatment techniques for calcified root canal.

PMID: 15133562 [PubMed - indexed for MEDLINE]