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]

[Cost effectiveness analysis of two methods of preparing molar root canals]

Shanghai Kou Qiang Yi Xue. 2006 Oct;15(5):493-6

Authors: Dou HQ, Wang Q, Sun SZ

PURPOSE: To evaluate the short-term clinical curative effects, cost effective ratio between ProFile nickel-titanium rotary preparation technique and stainless steel hand K-files preparation technique in molar root canal therapy. METHODS: All patients were randomly divided into two groups: 49 cases were prepared with stainless steel hand K-files in routine preparation technique; 45 cases were prepared with ProFile nickel-titanium rotary instruments in step-down technique. The clinical symptoms and cost were recorded. The data was analyzed by SPSS11.5 software package. RESULTS: The satisfactory rate of clinical effect of the NRPT group was significantly higher than SSPT(P = 0.034); The mean cost of the NRPT was significantly higher than SSPT (P = 0.001), the satisfactory rate of NRPT in severe curve subgroup was significantly higher than that of SSPT (P = 0.007), however, the C/E of NRPT was 394.52 Yuan less than SSPT. The former was 192.04 Yuan more than the latter in light curve subgroup. When it was classified by periapical condition before treatment, the satisfactory rate of NRPT was significantly higher than SSPT in negative subgroup yet (P = 0.012), the C/E of the former was 32.32 Yuan more than the latter; nevertheless, the C/E of the former was 376.47 Yuan more than the latter in positive subgroup; CONCLUSIONS: It is better to prepare with ProFile nickel-titanium rotary preparation technique in severe curve subgroup, however, the light curve subgroup should be prepared with stainless steel hand K-files preparation technique. To patients with positive periodontopathy, SSPT would save the cost of treatments, nevertheless, NRPT group have a higher short-term recent effect.

PMID: 17348222 [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]

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]

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]

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 d&#xE9;bridement 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 débridement, 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]

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]

[Root canal therapy of resinified teeth with surgical operating microscope and ultrasonic instruments]

Shanghai Kou Qiang Yi Xue. 2006 Apr;15(2):117-20

Authors: Xu Q, Lin JQ, Mai S, Liu JW

PURPOSE: To evaluate the role of surgical operating microscope and ultrasonic instruments in endodontic treatment of patients who underwent previous resinifying therapy. METHODS: 63 premolars and molars that had been treated with resinifying therapy before were selected for root canal therapy. The coronal portion of resinified root canals were negotiated with ultrasonic instruments under surgical operating microscope, and the apical portion was managed with small size hand files and 15% EDTA. The root canals of all cases were shaped by Nickel-Titanium rotary instruments Hero 642, and obturated with lateral condensation technique. The negotiation of root canal system, instrument fracture, alterations of canal morphology, and operation time were recorded. The efficiency of preparation and obturation was analyzed by radiographs before and after treatment. RESULTS: The root canals of 54 teeth were negotiated, enlarged and obturated, with a success rate of 85.7%. No complications were found, such as vertical fracture, ledge, perforation and instrument separation. Good result of treatment was achieved in the 54 cases. CONCLUSIONS: The use of surgical operating microscope and ultrasonic instruments is proved to be effective in negotiation of coronal portion of the resinified root canals. Nevertheless, the use of ultrasonic instruments in apical or curved portion of root canals is not encouraged.

PMID: 16685346 [PubMed - in process]

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]

Effect of cryogenic treatment on nickel-titanium endodontic instruments.

Int Endod J. 2005 Jun;38(6):364-71

Authors: Kim JW, Griggs JA, Regan JD, Ellis RA, Cai Z

AIM: To investigate the effects of cryogenic treatment on nickel-titanium endodontic instruments. The null hypothesis was that cryogenic treatment would result in no changes in composition, microhardness or cutting efficiency of nickel-titanium instruments. METHODOLOGY: Microhardness was measured on 30 nickel-titanium K-files (ISO size 25) using a Vicker's indenter. Elemental composition was measured on two instruments using X-ray spectroscopy. A nickel-titanium bulk specimen was analysed for crystalline phase composition using X-ray diffraction. Half of the specimens to be used for each analysis were subjected to a cryogenic treatment in liquid nitrogen (-196 degrees C) for either 3 s (microhardness specimens) or 10 min (other specimens). Cutting efficiency was assessed by recording operator choice using 80 nickel-titanium rotary instruments (ProFile 20, .06) half of which had been cryogenically treated and had been distributed amongst 14 clinicians. After conditioning by preparing four corresponding canals, each pair of instruments were evaluated for cutting efficiency by a clinician during preparation of one canal system in vitro. A Student's t-test was used to analyse the microhardness data, and a binomial test was used to analyse the observer choice data. Composition data were analysed qualitatively. RESULTS: Cryogenically treated specimens had a significantly higher microhardness than the controls (P < 0.001; beta > 0.999). Observers showed a preference for cryogenically treated instruments (61%), but this was not significant (P = 0.21). Both treated and control specimens were composed of 56% Ni, 44% Ti, 0% N (by weight) with a majority in the austenite phase. CONCLUSIONS: Cryogenic treatment resulted in increased microhardness, but this increase was not detected clinically. There was no measurable change in elemental or crystalline phase composition.

PMID: 15910471 [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]

[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]

Morphometric analysis of the effectiveness of different concentrations of sodium hypochlorite associated with rotary instrumentation for root canal cleaning.

Braz Dent J. 2004;15(1):36-40

Authors: Baratto-Filho F, Carvalho Jr JR, Fariniuk LF, Sousa-Neto MD, P&#xE9;cora JD, Cruz-Filho AM

This study evaluated the cleaning capacity of Profile.04 instruments with different concentrations of NaOCl solutions on flattened root canals. Twenty central mandibular incisors were divided into 4 groups: Group I: 0.5% NaOCl; Group II: 1% NaOCl; Group III: 5% NaOCl; Group IV: distilled and deionized water. After chemomechanical preparation, the teeth were submitted to histological preparation and morphometric analysis. Morphometric analysis showed that the 5% NaOCl was significantly more efficient in cleaning the root canal than 0.5% NaOCl and distilled water, which had the lowest levels of cleaning of the root canals (p<0.01).

PMID: 15322643 [PubMed - in process]

[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]

[The effects of three nickel-titanium rotary instruments on root canal curvature]

Shanghai Kou Qiang Yi Xue. 2001 Dec;10(4):333-5

Authors: Wei X, Cheung SP

OBJECTIVE: To investigate the effects of three nickel-titanium rotary instruments on root canal curvature and their working efficiency. METHODS: 64 curved mesial canals of extracted lower molars were randomly assigned to four groups: Flexofile, LightSpeed, ProFile, Qantec SC. Root canal preparation was carried out at two stages: first to size 30, then to size 40. The root canal curvatures before and after preparation as well as preparation time were measured. RESULTS: Preparation with Flexofile resulted in the maximum reduction of root canal curvatures. The differences between three nickel titanium (Ni-Ti) groups and Flexofile were statistically significant from bucco-lingual view (P<0.01). No significant differences were detected between pre- and post-operative curvatures within Ni-Ti groups when preparation was carried out to size 30 (P>0.05). Preparation with ProFile or Quantec SC instruments cost significantly less time than the other two groups P<0.01). CONCLUSION: Preparation with Ni-Ti rotary instruments maintained the root canal curvature to a maximum extent. The techniques were also timesaving.

PMID: 14993966 [PubMed]

Periapical surgery of 29 teeth. A comparison of conventional technique, microsaw and ultrasound.

Med Oral. 2002 Jan-Feb;7(1):46-9, 50-3

Authors: Vallecillo Capilla M, Mu&#xF1;oz Soto E, Reyes Botella C, Prados Sáchez E, Olmedo Gaya MV

OBJECTIVES: A clinical and radiological study is made of the results obtained with different periapical surgical techniques. MATERIAL AND METHODS: Twenty-nine single-root teeth from 29 patients with periapical pathology following correct endodontic treatment were divided into three groups: (A) 10 patients in which rotary instruments were used to perform osteotomy, apicoectomy and cavity preparation; (B) 10 patients in which rotary instruments were used to perform osteotomy and apical resection, with ultrasound root-end cavity preparation; and (C) 9 patients in which microsaws were used for osteotomy, and ultrasound for cavity preparation. All teeth were filled with IRM. Clinical and radiological controls were made after 10 days, one and 6 months, and one year. RESULTS: Clinical success with the absence of symptoms was achieved in 17 cases (58.6%), while in 16 patients (55.2%) the X-ray images showed complete bony regeneration (complete healing). The clinical success rate after one year was 40%, 70% and 66.7% in groups A, B and C, respectively, while complete radiographic healing was recorded in 30%, 60% and 77.8%. There were three failures in group A, two in group C, and none in group B. CONCLUSION: In conclusion, the best results were obtained when ultrasound was used for root-end cavity preparation.

PMID: 11788808 [PubMed - indexed for MEDLINE]