Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 5.896
Filtrar
1.
J Contemp Dent Pract ; 21(5): 539-542, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32690836

RESUMO

AIM: The aim of the present study was to investigate the role of the flat design compared with a non-flat designed instrument on the centering ability in a simulated root canal system. MATERIALS AND METHODS: Two file systems were chosen: the F-One (Fanta Dental, Shanghai, China) and a prototype with the same design but without the flat-side design. A total of 50 simulated L-shaped root canals in resin blocks were shaped with a new instrument each. Pre- and postcanal preparation images were captured and superimposed to measure and compare the canal transportation and evaluate the centering ability of each file. The t test was performed and the level of significance was set at p < 0.05. RESULTS: Prototype files removed significantly less resin from the inner and the outer parts of the canal and showed significantly higher mean transportation values. CONCLUSION: It can be concluded that the F-One file system demonstrated better shaping ability compared with the prototype file system in L-shaped resin-simulated canals. CLINICAL RELEVANCE: The present study showed the safety of the flat-side design, minimizing the risk of iatrogenic errors such as ledging, perforation, or zipping of the root canal.


Assuntos
Níquel , Titânio , China , Ligas Dentárias , Instrumentos Odontológicos , Cavidade Pulpar , Desenho de Equipamento , Preparo de Canal Radicular
2.
Shanghai Kou Qiang Yi Xue ; 29(2): 146-149, 2020 Apr.
Artigo em Chinês | MEDLINE | ID: mdl-32626876

RESUMO

PURSPOSE: To compare the shaping ability and dental cracks of Twisted File and S3 in severely curved molar root canal preparation. METHODS: Sixty extracted mandibular molars with mesiobuccal canals (canal curvature angles beyond 25°) were selected and divided randomly into 2 groups with 30 canals in each group. The canals were scanned by cone-beam CT(CBCT) before and after root canal preparation .The canal transportation was recorded at 3 points (3, 5, 7 mm to root tip). After root canal preparation,all the roots were horizontally sectioned 3,5 and 7mm from the apex. The slices were observed under optical stereomicroscope. SPSS 19.0 software package was used for statistical analysis. RESULTS: Transportations occurred in all groups. No significant difference was found between the two groups of canal transportation at the two points (5 mm and 7 mm to root tip) (P>0.05); at the point of 3 mm to the root tip,the transportation of canals prepared by S3 was obviously lesser than the canals prepared by TF. There was no significant difference in the incidence of dentinal cracks between the two groups (P>0.05). CONCLUSIONS: Under the conditions of severely curved molar root canal in extracted teeth, cracks were found in both groups, S3 was found to be better in maintaining original canal shape than TF system.


Assuntos
Níquel , Preparo de Canal Radicular , Ligas Dentárias , Instrumentos Odontológicos , Cavidade Pulpar , Desenho de Equipamento , Dente Molar , Titânio
3.
J Contemp Dent Pract ; 21(4): 351-352, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32584267

RESUMO

In the last decades, the use of nickel-titanium (Ni-Ti) rotary instruments has become the most effective and popular method among endodontists for shaping root canals, even if there are still concerns regarding the increased risks of intracanal breakage or weakening of the instruments.1,2 So manufacturers started to modify the cross-sectional geometrical aspects of the files in order to improve their resistance to torsional and cyclic fatigue. Design is a major feature in determining instruments' properties including cutting efficiency, removal of debris, stresses generated during instrumentation, and the relative resistance to these stresses; however, a perfect design is not existing and any change in design is likely to provide some advantages but also some disadvantages.3,4.


Assuntos
Níquel , Titânio , Estudos Transversais , Ligas Dentárias , Instrumentos Odontológicos , Desenho de Equipamento , Falha de Equipamento , Preparo de Canal Radicular
4.
J Contemp Dent Pract ; 21(2): 171-177, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-32381823

RESUMO

AIM: Nickel-titanium (NiTi) instruments were designed to be used in continuous rotation mode with controlled speed and torque and a sequence of different sizes. The reciprocating motion was purposed to improve cyclic fatigue of rotary instruments if compared to the conventional rotation. The purpose of this work was to compare the shaping ability of Reciproc R25, Mtwo #25/0.06 used as a single file, and Mtwo sequence used in reciprocating motion and in continuous rotation. MATERIALS AND METHODS: Forty-eight endodontic training resin blocks ISO 15, 2% taper, 7 mm radius, and a 60° angle of curvature were shaped with four different protocols. Group I (Rrsf) was shaped with Reciproc R25 used as a single file in a reciprocating motion. Group II (Mrsf) was shaped with Mtwo #25/0.06 used as a single file in a reciprocating motion. Group III (MSrec) was shaped with Mtwo sequence in reciprocating motion, and finally, group IV (MSrot) was shaped with the Mtwo sequence used in continuous rotation. Preoperative and postoperative images of the simulated canals were taken under standardized conditions and combined exactly. The amount of resin removed was determined at both the inner and outer sides of the canal curvature. The ability of the instruments to remain centered in the canal was determined by calculating a centering ratio. These data were analyzed statistically using two factors analysis of variance (ANOVA) with Bonferroni correction (Bonferroni post-hoc test). RESULTS: Group Rrsf produced a greater enlargement of the canal, especially on the outer side, in the apical and middle third (p < 0.05). Group MSrot produced a lower enlargement in the middle third (p < 0.05). Group Rrsf displayed a lower centering ratio in the apical third (p < 0.05). Group MSrot displayed a lower centering ratio in the coronal third (p < 0.05). CONCLUSION: The shaping of simulated canals using a sequence of instruments in continuous rotation resulted in a more centered preparation of the apical third. The reciprocating motion for all tested instruments produced a bigger enlargement of the canals. CLINICAL SIGNIFICANCE: Reciprocating movement results in a more pronounced canal enlargement but appears to be less respectful of the original canal curvature and produces more apical transportation than a sequence of rotary NiTi files with the same ending apical size.


Assuntos
Instrumentos Odontológicos , Preparo de Canal Radicular , Desenho de Equipamento , Teste de Materiais , Rotação
5.
Braz Oral Res ; 34: e039, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32374813

RESUMO

To compare the shaping ability of different single-file systems in the preparation of mesial curved canals of mandibular molars using micro-CT technology. Fifteen mesial roots of mandibular molars with two independent and curved canals (n = 30) were selected, scanned at a resolution of 26.7 µm anatomically matched, and distributed into three groups (n = 10), according to the preparation system: WaveOne 25.08, Reciproc 25.08, and OneShape 25.06. A final micro-CT scanning was performed, data sets were registered with their respective counterparts, and compared regarding the three-dimensional (volume, surface area, and structure model index - SMI) and two-dimensional (perimeter, area, roundness, major and minor diameters) parameters, as well as, canal transportation, using ANOVA and post hoc Tukey tests (α = 5%). Overall, no difference was observed between groups regarding area, perimeter, volume, surface area, and canal transportation (p > 0.05). Within group, no canal transportation was significantly higherobserved in the apical third (0.10 ± 0.05 mm) compared to coronal (0.08±0.040 mm) and middle (0.07 ± 0.03 mm) thirds (p < 0.05). Structure model index (SMI) was statistically higher after preparation with OneShape instrument (0.36 ± 0.26) compared to other systems (p < 0.05). Within the parameters of this study, similar shaping ability was observed in the preparation of mesial curved root canals of mandibular molars with Reciproc, OneShape and WaveOne systems.


Assuntos
Cavidade Pulpar/anatomia & histologia , Cavidade Pulpar/diagnóstico por imagem , Preparo de Canal Radicular/instrumentação , Análise de Variância , Instrumentos Odontológicos , Desenho de Equipamento , Humanos , Teste de Materiais , Dente Molar/anatomia & histologia , Valores de Referência , Estatísticas não Paramétricas , Microtomografia por Raio-X/métodos
6.
J Contemp Dent Pract ; 21(3): 277-279, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-32434974

RESUMO

AIM: To evaluate the cyclic fatigue resistance of Reciproc blue (RB) 40/0.06 instruments tested at room temperature (20° ± 0.5°C) and at body temperature (37° ± 0.5°C) in a simulated stainless steel canal. MATERIALS AND METHODS: Twenty-four new RB 40/0.06 instruments were randomly divided into two groups (n = 12) according to the temperature used. Dynamic fatigue testing was performed using an artificial stainless steel canal with a 60° curvature angle and a 5-mm radius of curvature. The temperature was controlled throughout the experiment with an underwater thermometer and a thermostat. The data were analyzed descriptively using the IBM SPSS 23.0 program, considering p < 0.05. RESULTS: The time to fracture of the RB instruments differed significantly between the two temperatures (1083.82 seconds at 20°C and 403.80 seconds at 37°C). No significant differences were found in fragment size. CONCLUSION: An increase in temperature reduces the cyclic fatigue resistance of RB 40/0.06 instruments. The results of the study suggest that an intracanal cooling system can be favorable to the fracture resistance of the tested instruments. CLINICAL SIGNIFICANCE: A cooling system of the root canal system is important in endodontic as it favors the cyclic fatigue resistance of Ni-Ti instruments.


Assuntos
Instrumentos Odontológicos , Preparo de Canal Radicular , Desenho de Equipamento , Falha de Equipamento , Temperatura
7.
Int Endod J ; 53(8): 1153-1161, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32358847

RESUMO

AIM: To study the impact of dentine cutting efficiency of rotary instruments on the lateral force they create when instrumenting simulated root canals in bovine dentine. METHODOLOGY: Lateral cutting efficiency of austenitic files (ProTaper Universal) was compared to that of counterparts of a reported identical geometrical design with a martensite phase component (ProTaper Gold) in bovine dentine disks (n = 6). Instrument shapes were studied using digital microscopy. The intracanal lateral force exerted by the two systems in simulated premolars (n = 9) made from bovine incisor roots containing a standardized narrow root canal of 16 mm length was monitored using a testing apparatus equipped with a torque-controlled endodontic motor/handpiece. Data were compared using parametric statistics, alpha error = 0.05. RESULTS: The geometrical design of the two systems under investigation was found to be identical. The martensitic nickel-titanium rotary files had a significantly (t-test, P < 0.05) higher lateral cutting efficiency than austenitic counterparts. This difference, however, did not impact the lateral force that was created when instrumenting simulated premolar root canals. Furthermore, lateral force peaks were generated with the progressively tapered instruments under investigation towards the full working length. Even though a glide path was prepared, the first instrument in the full-length sequence (S1) created the highest lateral force (anova/Tukey's HSD, P < 0.05). CONCLUSIONS: The current experimental set-up allows the study of the lateral force generated during root canal instrumentation. This force was not influenced by the dentine cutting efficiency of the instruments under investigation, but rather by their geometrical design.


Assuntos
Ligas Dentárias , Preparo de Canal Radicular , Animais , Bovinos , Instrumentos Odontológicos , Cavidade Pulpar , Dentina , Desenho de Equipamento , Fenômenos Mecânicos , Titânio , Torque
8.
J Endod ; 46(8): 1136-1143, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32413441

RESUMO

INTRODUCTION: The aim of this study was to evaluate the cyclic fatigue resistance of 3 replicalike rotary instruments compared with their original brand systems using continuous rotation and optimum torque reverse (OTR) kinematics. METHODS: New F1 rotary instruments (n = 20 per group) from ProTaper Universal (Dentsply Maillefer, Ballaigues, Switzerland) and ProTaper Gold (Dentsply Maillefer) original brand systems were compared with 3 replicalike instruments (U-File [Dentmark, Ludhiana, India], Super Files [Shenzhen Flydent Medical, Shenzhen, China], and Super Files Blue [Shenzhen Flydent Medical]) regarding cyclic fatigue resistance. In each group, the selected instruments were randomly distributed into 2 subgroups (n = 10) according to the kinematics. In the rotary group (ROT), the instruments were activated with a continuous clockwise rotation (300 rpm, 1.5 Ncm), whereas in the OTR group, asymmetric oscillatory motion was performed setting the OTR function at 300 rpm and adjusting the torque limit at the minimum level using the TriAuto ZX2 motor (J Morita, Kyoto, Japan). The time to fracture was recorded and statistically compared according to the kinematics (ROT × OTR) and the instrument type (replicalike × original brand) using the independent sample t test (α = 0.05). Additionally, the metal alloy characterization of each system was performed by differential scanning calorimetry and energy-dispersive X-ray spectroscopy. RESULTS: Statistical analysis revealed significantly higher time to fracture for all rotary systems tested in OTR motion compared with continuous rotation (P < .05) with a mean percentage increase ranging from 52.1% (ProTaper Gold) to 156.7% (U-File). The replicalike instruments showed a significantly higher time to fracture compared with the respective original brand instruments in either ROT or OTR motion (P < .05). Replicas presented austenitic temperatures above the ones displayed by the original brands and an almost equiatomic ratio between nickel and titanium elements. CONCLUSIONS: OTR motion significantly improved the fatigue resistance of both original and replicalike systems. The replicas showed higher cyclic fatigue resistance than original brand instruments and higher transition temperatures to the austenitic phase.


Assuntos
Ligas Dentárias , Falha de Equipamento , Fenômenos Biomecânicos , China , Instrumentos Odontológicos , Desenho de Equipamento , Índia , Preparo de Canal Radicular , Rotação , Estresse Mecânico , Titânio
9.
Hua Xi Kou Qiang Yi Xue Za Zhi ; 38(2): 160-165, 2020 Apr 01.
Artigo em Chinês | MEDLINE | ID: mdl-32314889

RESUMO

OBJECTIVE: This study aims to compare the efficiency of three kinds of microtube extraction devices, namely, instrument removal system (IRS), micro-retrieve and repair (MR&R) system, and MR&R system using modified microtube in removing separated instruments with different exposure lengths. METHODS: After a cross-section platform model was established, the IRS, MR&R, and MR&R modified microtube system with sidewall window reduced to 0.20 mm were used to retrieve various separated instrument models, and the differences in extraction effects were statistically analyzed by Chi-square test. The separated instrument models were divided into two groups: stainless steel and nickel-titanium instrument groups. In total, 23 instruments were tested for three times each. RESULTS: When the exposed length of separated instrument was 0.50 mm, the removal efficiency of the modified MR&R system group was significantly higher than those of the IRS and MR&R system groups (P<0.001). When the broken end of the fracture instrument was up to 1.00 mm, the success rates of the MR&R system and modified MR&R groups were significantly higher than that of the IRS group (P<0.01). No difference was observed among these three devices when the exposure length of separated instruments was 1.50 mm or higher. CONCLUSIONS: The MR&R and modified MR&R systems have good removal effect when the exposed length of separated instrument is small.


Assuntos
Instrumentos Odontológicos , Preparo de Canal Radicular , Ligas Dentárias , Cavidade Pulpar , Desenho de Equipamento , Falha de Equipamento , Aço Inoxidável , Titânio
10.
J Appl Oral Sci ; 28: e20190145, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32049132

RESUMO

OBJECTIVE: Ultrasonic wave technology is widely used during dental treatments. We previously demonstrated that this method protects the gingival tissue. However, the physiological change on the gingival microvasculature caused by this method remains unclear. The aim of this study was to investigate the relationship between the morphological and physiological effects on gingival microcirculation when preparing teeth, using the conventional dental turbine or ultrasonic method. METHODOLOGY: The lower premolar teeth of beagle dogs were prepared along the gingival margin by using a dental turbine or ultrasonic wave instrument. Gingival vasculature changes were investigated using scanning electron microscopy for corrosion resin casts. Gingival blood flow at the preparation site was determined simultaneously by laser Doppler flowmetry. These assessments were performed immediately (Day 0), at 7 days and 30 days after tooth preparation. RESULTS: At day 0, in the turbine group, blood vessels were destroyed and some resin leaked. Furthermore, gingival blood flow at the site was significantly increased. In contrast, the ultrasonic group demonstrated nearly normal vasculature and gingival blood flow similar to the non-prepared group for 30 days after preparation. No significant alterations occurred in gingival circulation 30 days after either preparation; however, the turbine group revealed obvious morphological changes. CONCLUSIONS: Based on multiple approach analyses, this study demonstrated that ultrasonic waves are useful for microvascular protection in tooth preparation. Compared with a dental turbine, ultrasonic wave instruments caused minimal damage to gingival microcirculation. Tooth preparation using ultrasonic wave instruments could be valuable for protecting periodontal tissue.


Assuntos
Gengiva/irrigação sanguínea , Microcirculação/fisiologia , Preparo do Dente/instrumentação , Ondas Ultrassônicas , Animais , Protocolos Clínicos , Instrumentos Odontológicos , Cães , Feminino , Humanos , Fluxometria por Laser-Doppler/métodos , Microscopia Eletrônica de Varredura , Reprodutibilidade dos Testes , Fatores de Tempo , Preparo do Dente/métodos
12.
Aust Endod J ; 46(2): 226-233, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32022376

RESUMO

This study evaluated the dynamic cyclic and torsional fatigue resistance of recently introduced TruNatomy instruments (TRN) and compare with HyFlex CM (HFC), Vortex Blue (VB) and FlexMaster (FM) instruments. Size 20, 0.04 taper of TRN, HFC, VB and FM instruments was tested for dynamic cyclic and torsional fatigue resistance. Dynamic cyclic fatigue resistance was evaluated using an artificial canal with a radius of 5 mm and a 90° angle of curvature. The number of cycles to failure (NCF) was calculated. The dynamic torsional fatigue resistance was evaluated by holding a 5 mm of the tip of each instrument in a metal block with composite resin. Torsional fatigue resistance was recorded by counting the number of load applications before fracture for each instrument. The HFC instruments had greater fatigue resistance than VB, TRN and FM. FM had a higher resistance to torsional stress than TRN, HFC and VB instruments.


Assuntos
Níquel , Titânio , Ligas Dentárias , Instrumentos Odontológicos , Desenho de Equipamento , Falha de Equipamento , Teste de Materiais , Preparo de Canal Radicular , Estresse Mecânico
13.
J Endod ; 46(3): 391-396, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32029265

RESUMO

INTRODUCTION: Information is scarce regarding current usage practices of nickel-titanium (NiTi) engine-driven instruments in clinical practice. Therefore, the specific purpose of this survey was to assess trends among endodontists regarding the use and reuse of NiTi instruments. METHODS: A 16-question survey was sent by e-mail to about 4000 active members of the American Association of Endodontists. Data were collected over a 6-month period and compared using chi-square tests. RESULTS: A total of 957 surveys were collected (response rate = 23%). Of the respondents, 40.2% worked in solo practices; among them, there were significantly fewer recent graduates (<10 years) compared with those who graduated more than 10 years ago. Furthermore, 41.7% were in a group practice, 4.3% in corporate practice, 10.7% in university settings, and 3% in the military. Overall, 98.3% of respondents reported using NiTi instruments. Respondents who graduated less than 25 years ago use NiTi instruments significantly more (99%) than those who graduated more than 25 years ago (92.6%). Although 22.9% of respondents buy presterilized instruments, 41.6% sterilize them before use, and 35.5% do not sterilize new instruments before use; dental officers in the military reported that they use sterile new instruments in 100% of cases. NiTi instruments were reused by 74% of respondents. The 2 largest segments of the specialist endodontic instrument market belonged to Dentsply (York, PA; 56.9%) and EdgeEndo (Albuquerque, NM; 28.8%). CONCLUSIONS: There are significant differences in the use of NiTi instruments among types of practice and years since graduation. There were noticeable changes compared with findings reported about 10 years ago.


Assuntos
Ligas Dentárias , Instrumentos Odontológicos , Endodontistas , Desenho de Equipamento , Humanos , Níquel , Padrões de Prática Odontológica , Preparo de Canal Radicular , Inquéritos e Questionários , Titânio , Estados Unidos
14.
BMC Oral Health ; 20(1): 38, 2020 02 04.
Artigo em Inglês | MEDLINE | ID: mdl-32019522

RESUMO

BACKGROUND: The purpose of this study was to compare the cyclic fatigue resistance of newly developed TruNatomy instruments (TRN) in single and double (S-shaped) curvature canals with HyFlex CM (HCM), Vortex Blue (VB) and RaCe (RC) instruments. METHODS: Size 20/.04 taper and size 25/0.04 of HCM, VB and RC were used. For TRN instruments, size 20/.04 taper (small) and size 26/.04 taper (prime) were used. The instruments were tested in artificial canals with double curvature (coronal curve; 60° curvature, 5 mm radius and apical curve; 70° curvature and 2 mm radius) and single curvature (60° curvature, 5 mm radius). The number of cycles to failure (NCF) was recorded. Data were statistically analyzed by Kruskal-Wallis and Dunn's multiple comparison tests. Weibull analysis was performed on NCF data. Statistical significant was set at p < 0.05. RESULTS: TRN and HCM revealed higher NCF compared with the other instruments for both tested sizes in single and double curvature canals (p < 0.05). TRN and HCM showed no statistically significant difference in the NCF (p > 0.05). The probability of survival was higher for HCM and TRN instruments than VB and RC instruments. CONCLUSIONS: HCM and TRN instruments were more resistant to cyclic fatigue than VB and RC instruments in single and double curvature canals. HCM and TRN instruments were anticipated to survive with higher number of cycles than the other tested instruments. RC instrument had the lowest fatigue resistance than the other instruments.


Assuntos
Ligas Dentárias , Instrumentos Odontológicos , Cavidade Pulpar/anatomia & histologia , Níquel , Preparo de Canal Radicular/instrumentação , Preparo de Canal Radicular/métodos , Titânio , Análise do Estresse Dentário , Desenho de Equipamento , Falha de Equipamento , Humanos , Teste de Materiais
15.
Niger J Clin Pract ; 23(1): 41-45, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31929205

RESUMO

Objective: This in vitro study aimed to compare the cyclic fatigue resistance of HyFlex EDM (HEDM), Vortex Blue (VB), ProTaper Gold (PG), and OneCurve (OC) nickel-titanium (NiTi) instruments. Materials and Methods: About 12 HEDM (25/.~), 12 VB (25/.06), 12 PG (25/.08), and 12°C (25/.06) instruments were included in this study. All the instruments were tested with a 60° angle of curvature and a 3-mm radius of curvature. All the instruments were utilized until fracture occurred, and then the number of cycles to failure (NCF) was calculated. The data were analyzed statistically using Kruskal-Wallis H and Mann-Whitney U-tests. The statistical significance level was set at P < 0.05. Results: HEDM instruments had the highest cyclic fatigue resistance among all the other instruments (P < 0.05). The OC instruments had a significantly higher fatigue resistance than the PG and VB instruments (P < 0.05); however, there was no significant difference between PG and VB instruments in the NCF (P > 0.05). Conclusion: Within the limitations of this in vitro study, it was found that the cyclic fatigue resistance was higher for the HEDM instruments than for the VB, PG, and OC instruments.


Assuntos
Ligas Dentárias/química , Instrumentos Odontológicos , Falha de Equipamento , Teste de Materiais , Preparo de Canal Radicular/instrumentação , Ligas , Desenho de Equipamento , Ouro , Humanos , Níquel/química , Titânio/química
16.
J Endod ; 46(3): 431-436, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31911005

RESUMO

INTRODUCTION: The aim of this study was to compare the influences from different access angles and curvature radii on cyclic fatigue resistance of nickel-titanium rotary files. METHODS: Two file systems (2Shape [TS; MicroMega, Besançon, France] and HyFlex CM [HCM; Coltène/Whaledent, Allstätten, Switzerland]) were used. A total of 192 instruments of TS #25/.04 (TS1), TS #25/.06 (TS2), HCM #25/.04, and HCM #25/.06 were evaluated at 3 insertion angles (0°, 10°, and 20°) and 2 radii (5 mm and 3 mm) in 16-mm stainless steel artificial canals with a 60° curvature. Cyclic fatigue resistance was determined by the number of cycles to failure (NCF) using a customized testing device. Data were analyzed statistically with the significance level established at 95%. RESULTS: In the 3-mm radius canal, the instruments showed lower cyclic fatigue resistance than in the 5-mm radius canal (P < .05). HCM #25/.06 and all .04 taper instruments had a significant NCF reduction at 20° and 10° in the 3-mm radius canal (P < .05), whereas TS2 showed no significant differences. In the 5-mm radius of curvature, although .06 taper instruments had no significant NCF reduction for each angle tested, .04 taper files exhibited significant NCF reduction when tested at 20° (P < .05). Comparing the same size instruments, HCM had higher NCF than TS (P < .05). Instruments with a .04 taper exhibited higher NCF than the .06 ones with the same heat treatment (P < .05). CONCLUSIONS: An inclined insertion into the canals decreased cyclic fatigue resistance of thermal-treated instruments with a .04 taper at all radii of curvature tested. The synergistic effect of a small radius of curvature and access angulation of heat-treated instruments decreases their fatigue resistance.


Assuntos
Ligas Dentárias , Instrumentos Odontológicos , Falha de Equipamento , Níquel , Titânio , Cavidade Pulpar , Desenho de Equipamento , Teste de Materiais , Rádio (Anatomia) , Preparo de Canal Radicular
17.
J Endod ; 46(3): 419-424, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31980201

RESUMO

INTRODUCTION: The aim of this study was to evaluate the effect of using the XP-endo Finisher (XPF; FKG Dentaire, La Chaux de Fonds, Switzerland) in teeth that have a traditional access cavity (TEC) and a contracted access cavity (CEC) design on the amount of decrease in the number of Enterococcus faecalis bacteria within the root canal system. METHODS: Eighty mandibular first molar teeth were selected and randomly divided into 2 groups: TEC and CEC (n = 40/group). After access cavity preparation in the 2 groups, 80 mesiobuccal root canals were contaminated with Enterococcus faecalis for 4 weeks. After the first sampling (S1), in order to perform root canal instrumentation, the TEC and CEC groups were further divided into 4 subgroups (10 teeth/group): Reciproc (VDW GmbH, Munich, Germany) and ProTaper Next (Dentsply Maillefer, Ballaigues, Switzerland) with or without XPF. Bacterial sampling from the root canals was performed with sterile paper points before (S1) and after (S2) instrumentation to determine the bacterial load. The bacterial reduction was counted as colony-forming units/mL and analyzed statistically by 3-factor repeated measures analysis of variance. Multiple comparisons of the main factor effect were performed using the Bonferroni correction (α < .05), all at 5% significance. RESULTS: The number of E. faecalis bacteria in all the samples with different cavity designs were significantly reduced after instrumentation. The lowest value of bacterial decrease percentage was observed in the CEC-Reciproc-XPF (82.8%) group. CONCLUSIONS: The bacterial reduction counts of E. faecalis were a similar level in the TEC and CEC cavities, and the use of XPF did not show significant differences between groups.


Assuntos
Cavidade Pulpar , Enterococcus faecalis , Preparo de Canal Radicular , Instrumentos Odontológicos , Enterococcus faecalis/isolamento & purificação , Alemanha , Preparo de Canal Radicular/métodos
18.
Odontology ; 108(2): 174-179, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31446499

RESUMO

The aim was to compare the shaping ability of different rotary nickel-titanium instruments in simulated S-shaped canals. One hundred S-shaped canals in resin blocks were prepared to an apical size 25 using F6 SkyTaper (Komet), Silk Files .04, Silk Files .06, Prototypes .04, and Prototypes .06 (all Mani) (20 canals/group). Material removal was measured at 20 measuring points, beginning 1 mm from the endpoint of preparation. Incidence of canal aberrations, preparation time, and instrument failures were also recorded. Statistical analyses were performed using ANOVA, Student-Newman-Keuls and Chi-square test. Pooled data of all measuring points revealed that canals instrumented with Prototypes .04 were significantly better centered than those prepared with all other instruments, while Prototypes .06 and both Silk Files performed significantly better than F6 SkyTaper (p < 0.05). The preparation time differed significantly between all groups and Prototypes .04 allowed the fastest preparation (p < 0.05). There was no statistically significant association between type of instrument and incidence of aberrations (p > 0.05). The cross-sectional design had a marked impact on the shaping ability of the instruments, and less tapered instruments maintained the original canal curvature better than instruments having greater tapers.


Assuntos
Níquel , Titânio , Estudos Transversais , Ligas Dentárias , Instrumentos Odontológicos , Cavidade Pulpar , Desenho de Equipamento , Humanos , Preparo de Canal Radicular
19.
Aust Endod J ; 46(1): 68-72, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31410934

RESUMO

This study compared the cyclic fatigue resistance (CFR) of three controlled memory (CM) nickel-titanium rotary files (One Curve, EdgeFile and HyFlex CM) in comparison with a file (ProTaper Next) made from M-wire nickel-titanium alloy at two different temperatures (room and intracanal) in an s-shaped canal. One hundred and sixty files were tested to determine the CFR of OneCurve, EdgeFile, HyFlex CM and ProTaper Next in an artificial canal at room and at intracanal temperature. The number of cycles to failure was recorded, and data were analysed. At both temperatures, ProTaper Next exhibited the lowest CFR compared with the other files (P < 0.05). At room temperature, there was no difference among the three CM files regarding CFR (P > 0.05). At intracanal temperature, OneCurve and EdgeFile exhibited more CFR than the HyFlex CM (P < 0.05). Testing at intracanal temperature caused a significant decrease in CFR of all tested files compared with testing at room temperature.


Assuntos
Ligas Dentárias , Preparo de Canal Radicular , Instrumentos Odontológicos , Desenho de Equipamento , Teste de Materiais , Temperatura , Titânio
20.
Dent Mater J ; 39(2): 251-255, 2020 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-31723092

RESUMO

This study aimed to evaluate the influence of a post-machining thermal treatment on canal-centering ability and torque/force generation of reciprocating nickel-titanium instruments. Simulated J-shaped resin canals were prepared with reciprocating instruments sharing identical geometric architecture and with/without post-machining thermal treatment (Reciproc Blue/Reciproc, VDW, Munich, Germany). Using an original automated root canal instrumentation and torque/force analyzing device, files were operated in a combination of reciprocation and up-and-down motion, and torque/force values were monitored. Canal-centering ratios were measured after superimposition of pre- and post-instrumentation images. Compared with Reciproc, Reciproc Blue showed a significantly lower canal-centering ratio (i.e., less deviation; p<0.05) at 0-1 mm from the apex and generated a significantly smaller upward maximum vertical force (p<0.05). Under standardized conditions using the automated device, Reciproc Blue showed better canal-centering ability and reduced screw-in forces than Reciproc, indicating that the post-machining thermal treatment confers superior performance to reciprocating nickel-titanium instruments.


Assuntos
Níquel , Titânio , Parafusos Ósseos , Instrumentos Odontológicos , Cavidade Pulpar , Desenho de Equipamento , Preparo de Canal Radicular
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA