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Results for “Root Canal Preparation”

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At least 55 records · Page 3Linked to original sources

PubMed2003

[Analysis the effect on the stress of root canal wall of pulpless teeth by different degree of root canal preparation].

OBJECTIVE: To analyze the stress variations of wall of root canal of pulpless teeth that resulted from different diameters of root canal. METHODS: On the basis of the finite-element model of the mandibular first molar that modified by routine, diameter of root canal was modified and enlarged so as to the diameter of root canal was 1/3 and 1/2 of root diameter, then modified models were loaded and the maximal stress of each part of teeth and wall of root canal was calculated. RESULTS: The results revealed that enlargement of root canal diameter will bring on increase of stress of root canal wall at the orifice and coronal 1/3. The stress difference of lateral loading was greater than that of vertical loading. CONCLUSION: The principle of root canal preparation should be infected material removed and good shape of root canal gained. Over-preparation is unnecessary and harmful.

Dental Pulp Cavity↗

PubMed1992

Effect of noncutting tipped instruments on the quality of root canal preparation using a modified double-flared technique.

Fifty-one extracted human first molar teeth with intact crowns and mature root apices were divided into three groups. Root curvature was determined. One of the root canals in the mesial root of lower molars, or the mesiobuccal root in maxillary molars, was prepared in one of three ways. In group 1 the root canals were instrumented using a modified double-flared technique with noncutting tipped files (Flex R); in group 2 the same files were used with a step-back technique. Group 3 was prepared with conventionally tipped files (K-Flex) using the step-back technique. A low viscosity polyvinyl siloxane impression material was injected into the prepared root canals and the specimens were decalcified, dehydrated, and cleared. The preparation was evaluated subjectively according to various desirable or undesirable criteria. A rating for overall quality of preparation was given. Statistical analysis showed that the teeth in group 1 had better overall preparation than those in group 3 (p < 0.05). There were no other statistically significant differences between the groups. The mean time required for each preparation technique was not statistically significantly different (p > 0.1). The use of a modified double-flared technique with non-cutting tipped files was shown to be an effective method for the preparation of curved root canals.

Analysis of Variance↗

PubMed1999

An evaluation of root canal preparation with the automated Excalibur endodontic handpiece.

The aim of this study was to evaluate several parameters for automated root canal preparation with the Excalibur handpiece compared with hand instrumentation. The parameters investigated were straightening of curved canals, cleaning ability, working safety (loss of working length, instrument separation, perforation), cross sectional diameter before and after enlargement, and working time. Sixty curved root canals were prepared using the Excalibur handpiece and 30 curved canals with conventional hand instruments to ISO-size 35. The Excalibur left significantly less debris and smear layer on the root canal walls, but hand preparation resulted in fewer unprepared regions. Root canal curvature was well maintained by either technique; the degree of straightening depended on original root canal curvature rather than on the preparation technique. The Excalibur removed significantly more dentin. In the coronal part of the root canal, hand instruments produced significantly more round and oval cross sections; in the middle and apical part no differences could be detected. Working time was shorter for hand preparation, but the difference was not significant. Manual instrumentation proved to be safe; no instrument fracture, perforation or loss of working length could be observed, whereas automated preparation resulted in one perforation and two cases of loss of working length.

Analysis of Variance↗

PubMed2005

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

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.

Humans↗

PubMed2005

Comparison of root canal preparation using RaCe and ProTaper rotary Ni-Ti instruments.

AIM: To compare various parameters of root canal preparation using RaCe (FKG Dentaire, La-Chaux-de-Fonds, Switzerland) and ProTaper (Dentsply Maillefer, Ballaigues, Switzerland) nickel-titanium (Ni-Ti) instruments. METHODOLOGY: Fifty extracted mandibular molars with mesial root canal curvatures between 20 degrees and 40 degrees were embedded in a muffle system. All root canals were prepared to size 30 using RaCe or ProTaper rotary instruments in low-torque motors with torque control and constant speed of 300 r.p.m. (ProTaper with ATR Tecnika, Advanced Technology Research, Pistoia, Italy; RaCe with EndoStepper, S.E.T., Olching, Germany). In both groups irrigation was performed with 2 mL NaOCl (3%) after each instrument size. Calcinase-Slide (lege artis, Dettenhausen, Germany) was used as a chelating agent with each instrument. The following parameters were evaluated: straightening of curved root canals, postoperative root canal cross-sections, safety issues and working time. Cleanliness of the root canal walls was investigated under the SEM using 5-score indices for debris and smear layer. Statistical analysis was performed using the following tests: Wilcoxon's test for straightening and working time was used (P < 0.05); Fisher's exact test for comparison of cross-sections and root canal cleanliness (P < 0.05). RESULTS: Both Ni-Ti systems maintained curvature well; the mean degree of straightening was less than 1 degrees for both systems. Following preparation with RaCe, 49% of the root canals had a round or oval diameter and 50% an irregular diameter, ProTaper preparations resulted in a round or oval diameter in 50% of the cases. For debris, RaCe and ProTaper achieved 47 and 49% scores of 1 and 2, respectively; there was no significant difference. For smear layer, RaCe and ProTaper achieved 51 and 33% scores 1 and 2, respectively; no statistically significant differences were apparent for the coronal and middle sections of the root canals, but RaCe performed significantly better in the apical region (Fisher's exact test, P = 0.0392). Two roots lost working length with RaCe instruments, whilst ProTaper preparation resulted in two roots loosing working length and one fractured instrument. Mean working time was shorter for ProTaper (90.9 s) than for RaCe (137.6 s); the difference was significant (Wilcoxon's test, P = 0.011). CONCLUSIONS: Both systems respected original root canal curvature well and were safe to use. Cleanliness was not satisfactory for both systems.

Dental Alloys↗

PubMed2002

[Analysis the stress variations of the root canal wall of pulpless tooth by different root canal preparation with finite-element method].

OBJECTIVE: To analyze the stress variations of the root canal wall of pulpless tooth by different root canal preparations. METHODS: On the basis of the set up model of the mandibular first molar, modified model was established by simulation of the routine or step-back root canal preparation and filling in. Then the maximum mises stress of each part of teeth and wall of root canal were calculated by special finite-element software. RESULTS: The stress-changing tendency is similar between two modified models but the maximum mises stress of the model by step-back technique is a little greater than one by routine. The stress of wall of mesial-buccal root canal was the greatest and one of mesial-lingual root canal was the least at three root canals. The stress-changing tendency of modified models was similar to original model. The maximum mises stress of modified models was near or less than one of original model except that of amalgam layer because of material property alteration. CONCLUSION: Not only routine but step-back technique is an effective and safe method. Dentist can choose them in practice.

English Abstract↗

PubMed1990

[Quantification of mechanical versus ultrasonic technique in root canal preparation].

The previous investigations of the cutting efficacy of the paracanal dentine with different endodontic instruments have not quantified the amount of the tissue removed. The purpose of this study was to compare the effectiveness of various mechanical canal instrumentations with ultrasonic technique by measuring the weight loss of the root dentine. The investigation concerned 60 single-canal roots of freshly extracted human teeth. Each canal was primarily prepared with Beutel rock reamers, size 3, with penetration to the apex. After desiccation in the thermostat at 60 degrees C for 65 hours, roots were weighed using an electronic scale (Mettler, AE-163, West Germany) with a precision of 10(-4) grams. Samples were devided into six groups according to the endodontic instrument: (1)K-tupbe reamers, (2)K-files, (3) Hedstroem files, (4) giromatic cleansers, (5) giromatic files, (6) ultrasonic files. After having been prepared the root canal was thoroughly irrigated with 4 ml saline, redesiccated and reweighed. Ultrasonic instrumentation was the most effective in removing the root canal dentine compared with all mechanical techniques (t-test; p less than 0.005). The smallest amount of root canal dentine was removed by giro-files. This was statistically significant compared with K-files, giro-files and ultrasonic files. There was no significant difference among the other mechanical instruments used in this study.

Dentin↗

PubMed1991

The radiographic platform: a new method to evaluate root canal preparation in vitro.

An in vitro method for evaluating root canal preparation in curved canals is presented. Based on Schneider's method, this technique makes it possible to obtain the position of the instrument before and after instrumentation in the same X-ray film. The use of the radiographic platform is a valuable research and teaching aid.

Dental Pulp Cavity↗

PubMed2003

ProTaper rotary root canal preparation: effects of canal anatomy on final shape analysed by micro CT.

AIM: To evaluate the relative performance of ProTaper nickel-titanium (Ni-Ti) instruments shaping root canals of varying preoperative canal geometry. METHODOLOGY: Extracted human maxillary molars were scanned, before and after shaping with ProTaper, employing micro computed tomography (muCT) at a resolution of 36 mum. Canals were three-dimensionally reconstructed and evaluated for volume, surface area, 'thickness' (diameter), canal transportation and prepared surface. Based on median canal volume, canals were divided into 'wide' and 'constricted' groups. Comparisons were made between mesiobuccal (mb), distobuccal (db) and palatal (p), as well as 'wide' and 'constricted' canals, using repeated-measures anova and Scheffé posthoc tests. RESULTS: Volume and surface area increased significantly and similarly in mb, db and p canals, and gross preparation errors were found infrequently. Root canal diameters, 5-mm coronal to the apex, increased from 0.38 to 0.65 mm, 0.42 to 0.66 mm and 0.57 to 0.79 mm for mb, db and p canals, respectively. Apical canal transportation ranged from 0.02 to 0.40 mm and was independent of canal type; 'wide' canals had a significantly higher (P < 0.05) proportion of unprepared surfaces than 'constricted' canals. CONCLUSIONS: Canals in maxillary molars were prepared in vitro using ProTaper instruments without major procedural errors. These instruments may be more effective in shaping narrow canals than wider, immature ones.

Analysis of Variance↗

PubMed2003

Comparative study of root-canal preparation using Lightspeed and Quantec SC rotary NiTi instruments.

AIM: To compare several parameters of root-canal preparation using two different rotary nickel-titanium (NiTi) instruments: Lightspeed (Lightspeed Inc, San Antonio, TX, USA) and Quantec SC (Tycom, Irvine, USA). METHODOLOGY: Fifty extracted mandibular molars with root-canal curvatures between 20 degrees and 40 degrees were embedded into a muffle system. All root canals were prepared to size 45 followed by a stepback in 1-mm increments to size 70 (Lightspeed) or 45 (Quantec SC), using a high-torque motor at 1300 or 350 r.p.m. respectively. In both groups, irrigation was performed with 2 mL NaOCl (3%) after each instrument size. RC-Prep (Premier, PA, USA) was used as a chelating agent. The following parameters were evaluated: straightening of curved root canals, postoperative root-canal diameter, working safety (instrument fractures, perforations, apical blockages, loss of working length (WL)), cleaning ability and working time. Cleanliness of the root-canal walls was investigated under SEM using 5-score indices for debris and smear layer. Statistical analysis was performed using the Wilcoxon's test (P < 0.05) for straightening and Fisher's exact test (P < 0.05) for comparison of cross-sections, contact between pre- and postoperative diameter, root-canal cleanliness and working time. RESULTS: Both NiTi systems maintained the curvature well: the mean degree of straightening was 1.8 degrees for Lightspeed and 1.7 degrees for Quantec SC; differences were not significant. Procedural incidents occurred with Quantec SC in 12 root canals (three fractures, four apical blockages and five cases of loss of WL), preparation with Lightspeed resulted in five fractures, one apical blockage and five cases of loss of WL (11 incidents). Following preparation with Lightspeed, 55.5% of the root canals had a round diameter, 25% an oval and 19.5% an irregular diameter; Quantec SC preparations resulted in a round diameter in 51.5%, oval shape in 33.3% and irregular cross-sections in 15.2% of the cases. Mean working time was similar for Quantec SC (161 s) and Lightspeed (155 s); the difference was not significant. For debris, Lightspeed and Quantec achieved 64 and 63% for scores 1 and 2, respectively. For smear layer, Lightspeed and Quantec achieved only 13.3 and 27.4% for scores 1 and 2, respectively. Differences were not significant for either debris or smear layer. CONCLUSIONS: Both systems respected original root-canal curvature well and prepared acceptable diameter forms. The cleaning ability was judged not satisfactory for both systems. Both systems showed deficiencies in working safety.

Chelating Agents↗

PubMed2001

The standardized-taper root canal preparation--Part 2. GT file selection and safe handpiece-driven file use.

AIM: To present guidelines on GT file selection, and safe operation. SUMMARY: It is not necessary to remove excessive dentine for effective root canal preparation. GT files allow safe, standardized preparation, and should be selected to fit the case in hand. Small Root canals should be prepared with 0.06 and 0.08 taper GT files, whilst Large Root canals should be prepared with 0.10 GT or 0.12 Accessory GT files. The greatest challenge is un-learning habits acquired from traditional instrumentation methods. GT files should be used with light touch, and without up-down pumping motions. Spin speeds should be controlled below 300 r.p.m. for routine preparation. GT files are subject to fatigue and should be tracked to avoid overuse. It is recommended that GT files are discarded after the equivalent of five root canal preparations. For severe curvatures, GT files should be single-case tools. KEY LEARNING POINTS: The standard GT file set comprises three instruments of 0.06, 0.08 and 0.10 taper. All are size 20 at the tip, and have a maximum diameter of 1 mm. Accessory GT files have a standard taper 0.12, and maximum diameter of 1.5 mm. They are available in tip sizes 35, 50 and 70. Large Roots are lower canines, upper anteriors, upper and lower single-rooted premolars, palatal roots of upper molars and distal roots of lower molars. They should be prepared with 0.10 GT or 0.12 Accessory GT files. Small Roots are lower incisors, multirooted premolars, buccal roots of upper molars and mesial roots of lower molars. They should be prepared with 0.06 or 0.08 GT files. All GT files should be used with light force and at the correct spin speed. GT files should be discarded after the equivalent of five root canal uses.

Bicuspid↗

PubMed1997

Root canal preparation.

Explore the source record for details and available documents.

Humans↗

PubMed1990

[Scanning electron microscopic studies on the efficacy of irrigated, hand root canal preparation].

The effectiveness of hand preparation and irrigation of 48 root canals of upper anterior teeth was evaluated by scanning electron microscopy. Independently of instrument (K reamer or combination K reamer and H file), irrigating solution (sodium chloride) and root canal dressing a similar degree of preparing and cleaning effectiveness of root canals was detected. In all groups a homogeneous or inhomogeneous smear layer of different thickness and extent dominated. A scale of preparing and cleaning effectiveness is recommended.

Dental Pulp Cavity↗

PubMed2003

[The effect of root canal preparation with nickel-titanium rotary instruments in reducing post-operative pain].

OBJECTIVE: To examine the effect of nickel-titanium rotary instruments in reducing post-operative pain. METHODS: 95 molars with pulpal and/or periapical involvement were randomly assigned to two groups for root canal preparation. One group was treated with ProFile nickel-titanium rotary instruments; the other was treated by using stainless steel hand files-FlexoFile. The incidence and degree of post-operative pain after root canal preparation in the two groups were recorded. RESULTS: In ProFile group, the incidence of post-operative pain was 27.7%, while 62.5% of the teeth developed post-operative pain after hand preparation. The difference between two groups was statistically significant (P < 0.01). CONCLUSION: Root canal preparation on molars with stainless steel hand files resulted in relatively high incidence of post-operative pain. Mechanical preparation using ProFile nickel-titanium instruments generated less post-operative pain and discomfort.

Adult↗

PubMed2003

Root-canal preparation with FlexMaster: canal shapes analysed by micro-computed tomography.

AIM: To evaluate the relative performance of FlexMaster nickel-titanium instruments shaping maxillary molar root canals in vitro. METHODOLOGY: Extracted human maxillary molars were scanned, before and after root-canal shaping, with FlexMaster, employing micro-computed tomography (microCT) at a resolution of 36 microm. Canals were three-dimensionally reconstructed and evaluated for volume, surface area, 'thickness' (diameter), canal transportation and prepared surface. Based on median canal volume, the canals were divided into 'wide' and 'constricted' groups. Comparisons were made between mesiobuccal (mb), distobuccal (db) and palatal (p), as well as 'wide' and 'constricted' canals, using anova and Scheffé post-hoc tests. RESULTS: Volume and surface area increased significantly and similarly in mb, db and p canals, and no gross preparation errors were found. Mean root-canal diameters, 5 mm coronal to the apex, increased from 0.45 to 0.65 mm, from 0.41 to 0.56 mm and from 0.79 to 0.85 mm for mb, db and p canals, respectively. Apical canal transportation ranged from 0.01 to 0.29 mm and was independent of canal type; 'wide' canals had a significantly higher (P < 0.05) proportion of unprepared surfaces than 'constricted' canals had. CONCLUSIONS: FlexMaster instruments shaped curved and narrow root canals in maxillary molars to sizes 40 and 45 without significant shaping errors. Canal anatomy had an insignificant impact on preparation, indicating that FlexMaster instruments were able to shape 'constricted' canals as well as 'wide' ones.

Analysis of Variance↗

PubMed1996

SEM analysis of smear layer removal after manual and automated handpiece root canal preparation.

Scanning electron microscopy was used to analyze the smear layer removal after root canal preparation by a manual technique and by an automated handpiece, the Canal Finder System (CFS). When 1% sodium hypochlorite was used as the irrigating solution, both manual and CFS techniques showed root canal walls with a dense smear layer obscuring the dentinal tubules entrance plus a large amount of debris. Root canal walls of the group of teeth treated with a chelating agent (EDTA) for 5 min and a final flush, after the preparation, with 1% sodium hypochlorite as an irrigating solution showed the cervical, middle and apical thirds extremely smooth and clear.

Dental High-Speed Equipment↗

PubMed2004

An analysis of endodontic treatment with three nickel-titanium rotary root canal preparation techniques.

AIM: To investigate clinical results of root canal treatment performed with the aid of nickel-titanium (NiTi) rotary instruments. SUMMARY: A total of 179 patients underwent root canal treatment with either (A) Lightspeed, or (B) ProFile .04 or (C) ProFile .04 and .06 or GT rotary instruments to create tapered preparations. In groups A and B, laterally condensed gutta-percha and AH Plus were used. Canals in group C were obturated with System B, Obtura II and Roth's 801 sealer. Initial and recall radiographs were assessed using the periapical index (PAI). Outcomes were analysed using chi-square tests, event-time analyses and logistic regression models. Two hundred and thirty-three teeth were radiographically assessed after a mean interval of 25.4 +/- 11.8 months. Favourable outcome of treatment, defined as PAI < 3 at recall was 86.7%. Logistic regression analysis and univariate analyses indicated that teeth with preoperative PAI scores >2 and retreated teeth had a significantly lower chance of healing compared with periapically healthy teeth and primary treatments, respectively. Preparation technique, length of fill and the type of sealer did not significantly affect healing rates. KEY LEARNING POINTS: Root canal treatment with NiTi root canal instrumentation systems renders favourable outcomes in more than 86% of the cases. Outcome is significantly affected by preoperative diagnoses but not by the specific choice of instrumentation system.

Adolescent↗

PubMed2004

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

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

Bismuth↗