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1.
Clin Oral Investig ; 2020 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-33236240

RESUMO

OBJECTIVES: This study evaluated the danger zone (DZ) in mesial roots of mandibular molars and the correlation between anatomical references of the DZ and some anatomical landmarks including tooth/root length, depth of mesial and distal grooves, and inter-canal orifices distance. MATERIAL AND METHODS: Twenty-eight mesial roots of mandibular molars with 2 independent canals were scanned and divided into 2 groups according to root length. The anatomical landmarks were correlated (Pearson or Spearman coefficients) with root level, thickness, and position of the DZ and also compared (independent samples t or Mann-Whitney tests) between the 2 groups at α = 5%. RESULTS: No statistical difference was observed between groups regarding DZ parameters and depth of mesial and distal grooves (P > 0.05). Orifice distance in group 2 (4.49 ± 0.75 mm) was significantly greater than group 1 (3.76 ± 0.89 mm) (P < 0.05). Significant correlations (P < 0.05) were found between (i) DZ level and root/tooth length (r = 0.54 and 0.49, respectively), (ii) DZ thickness and distal groove depth (r = - 0.45), and orifice distance (r = 0.38), and (iii) DZ position and depth of mesial (r = 0.39) and distal (r = 0.40) grooves. Other variables such as root length and distal groove depth (r = 0.28), and orifice distance and mesial groove depth (r = 0.36) were also correlated (P < 0.05). CONCLUSIONS: The length of tooth/root, the distance of canal orifices, and the depth of mesial/distal grooves of mesial roots of mandibular molars might be predictive factors for the root level, position, and thickness of the DZ. CLINICAL RELEVANCE: The length, distance of mesial canal orifices, and the depth of mesial and distal grooves of the mesial roots of mandibular molars might be moderate predictive factors for the root level, position, and thickness of the DZ.

2.
J Endod ; 2020 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-33045262

RESUMO

INTRODUCTION: This study assessed the number of mesial and distal canals of mandibular molars in which the R-Pilot pathfinding reciprocating instrument reached the working length (WL) during macro glide path procedure. Fracture and deformation rates were also evaluated. METHODS: One hundred fifty-six root canals of 52 teeth were scouted to the length of the apical foramen. Then the R-Pilot instrument was positioned at the canal orifice and activated. The instrument was moved by using a pecking motion and light apical pressure. This procedure was repeated in an attempt to reach the WL. The type of fracture and/or instrument deformation was assessed by scanning electron microscopy, whereas the roots with fractured instruments were scanned through micro-computed tomography. The percentage frequency distribution of fractures, deformations, and root canals in which the R-Pilot reached the WL were recorded and statistically compared by using the Pearson's χ2 test with α = 5%. RESULTS: R-Pilot instruments reached the WL in 139 root canals (89.10%), and χ2 test showed a significant difference between the observed frequencies and the expected frequencies (χ2 = 95.41, P = .000). The observed frequencies of fractures (2.56%) and deformations (1.92%) were also significantly lower than the expected (fracture: χ2 = 140.41, P = .000; deformation: χ2 = 144.23, P = .000). Fractures occurred mostly at the apical and curved parts of the root canals. CONCLUSIONS: R-Pilot reached the WL in 89.10% of the root canals of mandibular molars with fracture and deformation rates of 2.56% and 1.92%, respectively.

3.
Restor Dent Endod ; 45(2): e25, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32483542

RESUMO

Objectives: This systematic review evaluated the influence of autoclave sterilization procedures on the cyclic fatigue resistance of heat-treated nickel-titanium (NiTi) instruments. Materials and Methods: A systematic search without restrictions was conducted in the following electronic databases: PubMed, Scopus, Web of Science, ScienceDirect, Cochrane, and Open Grey. The hand search was also performed in the main endodontic journals. The eligible studies were submitted to the methodological assessment and data extraction. Results: From 203 abstracts, a total of 10 articles matched the eligible criteria. After reading the full articles, 2 were excluded because of the absence of the heat-treated instruments in the experimental design and 3 due to the lack of a control group using heat-treated instruments without autoclave sterilization. From the 5 included studies, 1 presented a low risk of bias, 3 presented moderate and 1 high risk. It was observed heterogeneous findings in the included studies, with autoclave sterilization cycles increasing, decreasing or not affecting the cyclic fatigue life of heat-treated NiTi instruments. However, the retrieved studies evaluating the cyclic fatigue resistance of endodontic instruments presented different protocols and assessing outcomes, this variability makes the findings less comparable within and also between groups and preclude the establishment of an unbiased scientific evidence base. Conclusions: Considering the little scientific evidence and considerable risk of bias, it is still possible to conclude that autoclave sterilization procedures appear to influence the cyclic fatigue resistance of heat-treated NiTi instruments.

4.
J Endod ; 45(9): 1135-1141, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31350048

RESUMO

INTRODUCTION: The purpose of this study was to evaluate the ability of the XP-endo Shaper instrument (FKG Dentaire, La Chaux-de-Fonds, Switzerland) during the removal of root fillings from oval-shaped canals. M-Wire Reciproc and Reciproc Blue systems (VDW, Munich, Germany) were used as reference instruments for comparison, and micro-computed technology was used as an analytical tool. METHODS: Thirty mandibular incisors with oval-shaped canals were matched based on similar anatomic features of the canal (eg, volume, aspect ratio, and 3-dimensional configuration) after scanning procedures. The canals were prepared with M-Wire Reciproc R25 instruments and filled with gutta-percha and AH Plus sealer (Dentsply DeTrey, Konstanz, Germany) using the continuous wave of condensation technique. Then, the sample was allocated into 3 experimental groups (n = 10) according to the retreatment protocol used: M-Wire Reciproc, Reciproc Blue, and XP-endo Shaper. M-Wire Reciproc R25, Reciproc Blue R25, and XP-endo Shaper instruments were used to remove the root fillings. Apical enlargement was performed with M-Wire Reciproc R40, Reciproc Blue R40, and BioRace BR5 (FKG Dentaire) instruments. Each sample was scanned after each endodontic procedure. The volume of remaining root filling material was quantified before and after apical enlargement. The percentage volumes of root filling reduction in relation to the instrumented canals at both time points (before and after apical enlargement) were calculated and considered for statistical analysis. Data were analyzed statistically with a significance level of 5%. RESULTS: Reciproc Blue presented significantly lower removal of filling material compared with the XP-endo Shaper (Tukey test, P < .05). No difference was detected either between M-Wire Reciproc and Reciproc Blue (Tukey test, P > .05) or M-Wire Reciproc and XP-endo Shaper (Tukey, P > .05). The increase of apical enlargement significantly improved the removal of root fillings from the root canals (P < .05); this effect was similar for all systems (time point × file system, P > .05). CONCLUSIONS: The XP-endo Shaper instrument showed a higher percentage of root filling removal, but no differences were observed comparing M-Wire Reciproc with the XP-endo Shaper or Reciproc Blue. The increase of apical enlargement improved the removal of root fillings in all groups. None of them was able to render root canals completely free from root fillings.


Assuntos
Materiais Restauradores do Canal Radicular , Obturação do Canal Radicular , Instrumentos Odontológicos , Cavidade Pulpar , Alemanha , Guta-Percha , Humanos , Retratamento , Preparo de Canal Radicular , Microtomografia por Raio-X
5.
J Endod ; 45(2): 194-198, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30711177

RESUMO

INTRODUCTION: This study assessed the frequency in which Reciproc Blue R25 instruments (VDW, Munich, Germany) reached the full working length (WL) of mandibular molar canals without a glide path. The influence of the type of electric motor (ie, conventional corded or cordless) on the instrument's performance was also assessed. METHODS: One hundred mandibular molars with slight to moderate root canals were selected and randomly assigned into 1 of 2 experimental groups according to the type of electric motor used: conventional corded (VDW Silver, VDW) or cordless motors (VDW.CONNECT Drive, VDW). Therefore, 50 molars and 154 root canals were selected for each motor. Reciproc Blue R25 instruments were used until reaching two thirds of the estimated WL. Then, a size 10 K-file was passively inserted to determine the full WL. No active instrumentation movement was performed with a size 10 K-file. Independently, whether a size 10 K-file reached the apex or not, Reciproc Blue R25 instruments were used to complete canal preparation. When the Reciproc Blue R25 instrument was able to reach the full WL, the case was classified as "reaching the full working length" (RFWL). If the instrument was not able to reach the full WL, the case was classified as "not reaching the full working length" (NRFWL). The chi-square test of goodness of fit was used to verify whether the observed frequencies of RFWL and NRFWL adhered to the expected ones. A 5% cutoff level of significance was considered for statistical assumptions. RESULTS: Reciproc Blue R25 instruments were able to reach the full WL in 304 root canals (98.70%). The chi-square test revealed the observed frequencies of RFWL and NRFWL to be significantly different from the expected frequencies (χ2 = 292,208, P = .000). The frequency of RFWL and NRFWL was exactly the same for both types of electric motors. No instrument fractured, and a single file deformed. In 50 of 308 root canals, a size 10 K-file was unable to passively reach the full WL. From these 50 canals, Reciproc Blue R25 instruments were able to reach the full WL in 47 of them. CONCLUSIONS: Reciproc Blue R25 instruments were able to reach the full WL in a high frequency of cases. The type of electric motor used did not interfere in the frequency of RFWL cases. No instrument fractured, and a single file deformed.


Assuntos
Instrumentos Odontológicos , Desenho de Equipamento , Preparo de Canal Radicular/instrumentação , Fontes de Energia Elétrica , Humanos , Mandíbula , Dente Molar
6.
Clin Oral Investig ; 23(7): 3087-3093, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30417226

RESUMO

OBJECTIVE: To compare the effectiveness of the XP-endo Finisher instrument and passive ultrasonic irrigation (PUI) as final irrigation protocols on the removal of accumulated hard-tissue debris (AHTD) from oval-shaped canals using micro-computed tomographic (micro-CT) analysis. METHODS: Twenty mandibular incisors were anatomically pair-matched based on similar morphological dimensions (length, volume, aspect ratio, and configuration) through micro-CT analysis, prepared with Reciproc R25 instrument, scanned again, and assigned to one of the two experimental groups (n = 10), according to the final irrigation protocol: XP-endo Finisher and PUI. After the final irrigation protocols, the specimens were rescanned and the registered datasets were examined to quantify the amount of AHTD. Data were statistically analyzed using Student's t test with a significance level of 5%. RESULTS: The final irrigation protocols were highly similar in terms of volumetric percentage reduction of AHTD (P = 1.000). CONCLUSIONS: XP-endo Finisher and PUI showed the same effectiveness on the removal of AHTD. None of the tested final irrigation protocols completely removed the AHTD from oval-shaped root canals. CLINICAL RELEVANCE: AHTD may be considered clinically relevant because it could harbor bacterial contents away from the disinfection procedures. Both final irrigation protocols were effective on the removal of AHTD.


Assuntos
Cavidade Pulpar , Preparo de Canal Radicular , Ultrassom , Humanos , Incisivo , Irrigantes do Canal Radicular , Irrigação Terapêutica , Microtomografia por Raio-X
7.
Clin Oral Investig ; 23(2): 681-687, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29744723

RESUMO

OBJECTIVES: This study aimed to compare four final irrigation protocols (passive ultrasonic irrigation [PUI], EndoVac, Self-Adjusting File [SAF] and EasyClean) on the removal of accumulated hard-tissue debris (AHTD) from mesial canals of mandibular molars through microcomputed tomographic (micro-CT) analysis. MATERIALS AND METHODS: Forty mesial roots of mandibular molars presenting isthmuses type I or III were scanned in a micro-CT device and instrumented up to Reciproc R40 instrument. After the completion of canal preparations, root canals of each group were submitted to a final rinse using 20 mL of solution (16 mL of 5.25% NaOCl and 4 mL of 17% EDTA) in a total time of 5 min according to one of the four final irrigation protocols (n = 10): PUI, EndoVac, SAF and EasyClean operated at reciprocating motion. The sample was scanned again after canal preparation and after the use of the final irrigation protocols, and the registered data sets were examined to evaluate the percentage of AHTD. Data were statistically compared using the Tukey test with a significance level set at 5%. RESULTS: All groups presented a decrease on the accumulation of hard-tissue debris after the use of the final irrigation protocols (P < 0.05). No significant differences in the removal of AHTD were observed among the final irrigation protocols (P > 0.05). CONCLUSIONS: All final irrigation protocols showed the same effectiveness in the removal of AHTD. None of them was able to render mesial canals of mandibular molars completely free from packed debris. CLINICAL RELEVANCE: This study highlighted that all final irrigation protocols (PUI, EndoVac, SAF, and EasyClean) promoted a similar removal of AHTD. However, none of the final irrigation protocols was able to render mesial canals of mandibular molars completely free from packed debris.


Assuntos
Cavidade Pulpar/diagnóstico por imagem , Cavidade Pulpar/cirurgia , Dente Molar/diagnóstico por imagem , Dente Molar/cirurgia , Irrigantes do Canal Radicular , Preparo de Canal Radicular/métodos , Irrigação Terapêutica/métodos , Microtomografia por Raio-X , Humanos , Imageamento Tridimensional , Ultrassom
8.
J Clin Exp Dent ; 10(10): e1040-e1044, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30386511

RESUMO

Dens invaginatus (DI) represents an endodontic challenge because of its complex root canal morphology. This case report presents the clinical management of a 22-year-old woman with type II DI in right maxillary lateral incisor with a painful swelling. Pulp testing revealed no response with the tooth. Type II DI with open apex and large periradicular lesion was seen on radiograph. The treatment was planned by using cone-beam computed tomography (CBCT) imaging. Canal treatment was completed in two appointments with the aid of a dental operating microscope. In the first appointment, the internal anatomy was modified using an ultrasonic tip, and chemo-mechanical preparation was performed using the XP-endo Finisher instrument and NaOCl; calcium hydroxide intracanal dressing was used for one month. In the second appointment, an apical plug of mineral trioxide aggregate (MTA) Repair HP was performed and the remaining pulp space was then filled with gutta-percha and AH Plus sealer using the continuous wave of condensation technique. At the fourteen-month reevaluation, the patient was asymptomatic, the tooth had remained functional, and radiographic and CBCT assessment showed significant osseous healing of the lesion. Successful non-surgical management of the present type II DI was achieved in the present case. The association of CBCT, dental operating microscope, XP-endo Finisher, NaOCl and MTA Repair HP were important for ensuring a predictable outcome. Key words:Cone beam computed tomography, dens invaginatus, MTA apexification, XP-endo Finisher.

9.
J Endod ; 44(7): 1146-1150, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29861067

RESUMO

INTRODUCTION: The present study aimed to assess canal preparation outcomes achieved by the new Reciproc Blue instrument using micro-computed tomography technology. M-Wire Reciproc was used as a reference instrument for comparison. METHODS: Seven pair-matched mesial roots of mandibular molars presenting similar anatomic features of the canal (length, volume, surface area, and configuration) were selected after scanning procedures and assigned to 1 of the 2 groups according to the instrument used, M-Wire Reciproc and Reciproc Blue. After canal instrumentation, the specimens were rescanned, and the registered preoperative and postoperative datasets were examined to evaluate the percentages of removed dentin, untouched canal walls, and degree of canal transportation. Comparisons regarding the above outcomes between the 2 groups were done by using paired t test with the alpha-type set at 5%. RESULTS: Root canals prepared with conventional M-Wire Reciproc or Reciproc Blue were found to present similar shaping properties with no significant differences in the tested parameters. CONCLUSIONS: M-Wire Reciproc and Blue Reciproc presented similar shaping outcomes.


Assuntos
Preparo de Canal Radicular/instrumentação , Microtomografia por Raio-X , Cavidade Pulpar/diagnóstico por imagem , Cavidade Pulpar/cirurgia , Humanos , Dente Molar/diagnóstico por imagem , Dente Molar/cirurgia , Preparo de Canal Radicular/métodos , Microtomografia por Raio-X/instrumentação , Microtomografia por Raio-X/métodos
10.
Restor Dent Endod ; 43(1): e5, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29487836

RESUMO

Objectives: This study evaluated the amount of remaining root canal filling materials after retreatment procedures performed by undergraduate students using manual, rotary, and reciprocating techniques through micro-computed tomographic analysis. The incidence of instrument fracture and the instrumentation time were also evaluated. Materials and Methods: Thirty maxillary single rooted teeth were prepared with Reciproc R25 files and filled with gutta-percha and AH Plus sealer by the continuous wave of condensation technique. Then, the specimens were assigned to 3 groups (n = 10), according to the retreatment technique used: manual, rotary, and reciprocating groups, which used K-file, Mtwo retreatment file, and Reciproc file, respectively. Retreatments were performed by undergraduate students. The sample was scanned after root canal filling and retreatment procedures, and the images of the canals were examined to quantify the amount of remaining filling material. The incidence of instrument fracture and the instrumentation time were recorded. Results: Remaining filling material was observed in all specimens regardless of the technique used. The mean volume of remaining material was significantly lower in the Reciproc group than in the manual K-file and Mtwo retreatment groups (p < 0.05). The time required to achieve a satisfactory removal of canal filling material and refinement was significantly lower in the Mtwo retreatment and Reciproc groups (p < 0.05) when compared to the manual K-file group. No instrument fracture was observed in any of the groups. Conclusions: Reciproc was the most effective instrument in the removal of canal fillings after retreatments performed by undergraduate students.

11.
J Endod ; 44(1): 168-172, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29079058

RESUMO

INTRODUCTION: The purpose of this study was to evaluate the cyclic and torsional fatigue resistance of the XP-endo Shaper (FKG Dentaire, La Chaux-de-Fonds, Switzerland) and TRUShape (Dentsply Tulsa Dental Specialties, Tulsa, OK) instruments. METHODS: Twenty XP-endo Shaper (30/0.01) instruments and 20 TRUShape (30/0.06v) instruments were used. Cyclic fatigue resistance was tested by measuring the number of cycles and time to fracture in an artificial stainless steel canal with a 60° angle and a 5-mm radius of curvature (n = 10). The torque and angle of rotation at failure of new instruments (n = 10) were measured according to ISO 3630-1. The fracture surface of all fragments was examined with a scanning electron microscope. Results were statistically analyzed using the Student t test at a significance level of P < .05. RESULTS: The XP-endo Shaper instruments showed a significantly longer number of cycles to fracture and time to failure in seconds than the TRUShape instruments (P < .05). The XP-endo Shaper also presented a lower maximum torque load (P < .05) but a significantly higher angular rotation to fracture than TRUShape (P < .05). CONCLUSIONS: The XP-endo Shaper instruments showed a higher cyclic fatigue resistance and angle of rotation to fracture but lower torque to failure than TRUShape instruments.


Assuntos
Instrumentos Odontológicos , Desenho de Equipamento , Falha de Equipamento , Estresse Mecânico , Propriedades de Superfície , Torção Mecânica
12.
Clin Oral Investig ; 22(1): 109-118, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29101548

RESUMO

OBJECTIVE: This systematic review was performed to answer the following question: do contracted endodontic cavities (CECs) increase resistance to fracture in extracted human teeth compared to traditional endodontic cavities (TECs)? METHODS: A literature search without restrictions was carried out in PubMed, Science Direct, Scopus, Web of Science, and Open Grey databases. Articles were selected by two independent reviewers. In addition, a reference and hand search was also fulfilled. All included in vitro studies evaluated the influence of CECs on strength to fracture in extracted human teeth and compared to TECs. The quality of the selected studies was evaluated and they were classified as having a low, moderate or high risk of bias. RESULTS: A total of 810 articles were obtained in the electronic search. After the application of the eligibility criteria, reference and hand search, and duplicate removal, six studies were included in this systematic review. All included studies evaluated the influence of CECs on strength to fracture in extracted human teeth and compared to TECs. Characteristics investigated in the selected articles included the sample size and tooth type, access cavity design, filling and restoration procedures, load at fracture test characteristics, and results. The studies demonstrated large variability among the fracture resistance values and standard deviations and low power. Three of the reviewed studies presented low risk of bias and the other three showed medium risk of bias. CONCLUSION: Overall, this systematic review of in vitro studies showed that there is no evidence that supports the use of CECs over TECs for the increase of fracture resistance in human teeth. CLINICAL RELEVANCE: Recently, CECs have gained attention in endodontics due to maximum tooth structure preservation including the pericervical dentin, which could improve the strength to fracture of endodontically treated teeth. However, the influence of access cavity design on fracture resistance remains limited and controversial.


Assuntos
Preparo da Cavidade Dentária/métodos , Restauração Dentária Permanente/métodos , Fraturas dos Dentes/prevenção & controle , Dente não Vital/terapia , Análise do Estresse Dentário , Humanos , Técnicas In Vitro
13.
Aust Endod J ; 44(3): 260-266, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28940891

RESUMO

This study assessed the percentage of untouched canal areas and the amount of debris accumulation after canal preparation with ProTaper Next (PTN) and Twisted File Adaptive (TFA) systems using micro-computed tomographic (micro-CT) imaging. Twenty isthmus-containing mesial roots of mandibular molars were anatomically matched through micro-CT evaluation and randomly assigned to one of the two experimental groups (n = 10), according to the system used for canal preparation: PTN (X1 and X2 files using rotary motion) and TFA (SM1 and SM2 files using adaptive motion). After canal preparation up to ISO size 25, the specimens were then scanned and the matched images of the mesial canals, before and after preparation, were examined from the furcation level to the apex to quantify the untouched surface canal areas and to evaluate the amount of accumulated debris. An independent samples t-test and a Mann-Whitney test were used, respectively, to compare these variables between the groups with a significance level set at 5%. Root canals prepared with either PTN or TFA systems were found to present similar untouched canal surface areas (P = 0.52) and hard-tissue debris accumulation (P = 0.39). Both systems produced a suboptimal and similar mechanical preparation of the mesial canals of mandibular molars and were not able to yield root canals completely free from packed hard-tissue debris.


Assuntos
Instrumentos Odontológicos , Materiais Restauradores do Canal Radicular/química , Preparo de Canal Radicular/instrumentação , Preparo de Canal Radicular/métodos , Tomografia Computadorizada por Raios X/métodos , Desenho de Equipamento , Humanos , Dente Molar , Radiografia Dentária/métodos , Fatores de Risco , Amostragem , Estatísticas não Paramétricas , Extração Dentária
14.
J Endod ; 43(9): 1553-1558, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28735793

RESUMO

INTRODUCTION: The purpose of this study was to evaluate the development of dentinal microcracks after root canal preparation with Reciproc and ProTaper Universal systems using an in situ cadaver model by means of a micro-computed tomography (micro-CT) imaging system. METHODS: At autopsy, 8 maxillary bone blocks having at least the first and second premolar teeth (n = 16) were excised, scanned at a resolution of 13.18 µm, and randomly distributed into 2 groups (n = 8) according to the preparation protocol: Reciproc and ProTaper Universal systems. Root canals were prepared up to R25 and F2 instruments in the Reciproc and ProTaper Universal groups, respectively. After the preparation procedures, the specimens were scanned again, and the registered preoperative and postoperative cross-section images of the roots (n = 19,060) were screened to identify the presence of dentinal defects. RESULTS: In the Reciproc group, 9176 cross-section images were analyzed, and no crack was observed. In the ProTaper Universal group, 244 of 9884 cross-section slices (2.46%) had dentinal defects; however, all defects were already present in the corresponding preoperative images, indicating that no new microcrack was created after canal preparation. CONCLUSIONS: In situ root canal preparation of maxillary premolars with Reciproc and ProTaper Universal systems did not induce the formation of dentinal microcracks in a cadaver model as observed by micro-CT.


Assuntos
Dentina/diagnóstico por imagem , Dentina/lesões , Preparo de Canal Radicular/efeitos adversos , Microtomografia por Raio-X , Adulto , Cadáver , Humanos , Adulto Jovem
15.
J Endod ; 43(10): 1657-1662, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28739013

RESUMO

INTRODUCTION: The aim of this study was to assess the influence of contracted endodontic cavities (CECs) on root canal detection, instrumentation efficacy, and fracture resistance assessed in maxillary molars. Traditional endodontic cavities (TECs) were used as a reference for comparison. METHODS: Thirty extracted intact maxillary first molars were scanned with micro-computed tomographic imaging at a resolution of 21 µm, assigned to the CEC or TEC group (n = 15/group), and accessed accordingly. Root canal detection was performed in 3 stages: (1) no magnification, (2) under an operating microscope (OM), and (3) under an OM and ultrasonic troughing. After root canal preparation with Reciproc instruments (VDW GmbH, Munich, Germany), the specimens were scanned again. The noninstrumented canal area, hard tissue debris accumulation, canal transportation, and centering ratio were analyzed. After root canal filling and cavity restoration, the sample was submitted to the fracture resistance test. Data were analyzed using the Fisher exact, Shapiro-Wilk, and t tests (α = 0.05). RESULTS: It was possible to locate more root canals in the TEC group in stages 1 and 2 (P < .05), whereas no differences were observed after stage 3 (P > .05). The percentage of noninstrumented canal areas did not differ significantly between the CEC (25.8% ± 9.7%) and TEC (27.4% ± 8.5%) groups. No significant differences were observed in the percentage of accumulated hard tissue debris after preparation (CEC: 0.9% ± 0.6% and TEC: 1.3% ± 1.4%). Canal transportation was significantly higher for the CEC group in the palatal canal at 7 mm from the apical end (P < .05). Canal preparation was more centralized in the palatal canal of the TEC group at 5 and 7 mm from the apical end (P < .05) and in the distobuccal canal of the CEC group at 5 mm from the apical end (P < .05). There was no difference regarding fracture resistance among the CEC (996.30 ± 490.78 N) and TEC (937.55 ± 347.25 N) groups (P > .05). CONCLUSIONS: The current results did not show benefits associated with CECs. This access modality in maxillary molars resulted in less root canal detection when no ultrasonic troughing associated to an OM was used and did not increase fracture resistance.


Assuntos
Cavidade Pulpar/anatomia & histologia , Cavidade Pulpar/diagnóstico por imagem , Dente Molar/anatomia & histologia , Preparo de Canal Radicular/métodos , Instrumentos Odontológicos , Humanos , Maxila , Dente Molar/diagnóstico por imagem , Dente Molar/lesões , Preparo de Canal Radicular/instrumentação , Fraturas dos Dentes , Microtomografia por Raio-X
16.
J Endod ; 43(4): 619-622, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28216274

RESUMO

INTRODUCTION: The aim of the present study was to evaluate the percentage frequency of dentinal micro-cracks observed after root canal preparation with TRUShape and Self-Adjusting File (SAF) systems by means of micro-computed tomography imaging analysis. A conventional full-sequence rotary system (BioRace) and a single-file reciprocation system (Reciproc) were used as reference techniques for comparison because of their known assertive cutting efficiency. METHODS: Forty anatomically matched mandibular incisors were selected, scanned at a resolution of 14.25 µm, and assigned to 4 experimental groups (n = 10), according to the preparation protocol: TRUShape, SAF, BioRace, and Reciproc systems. After the experimental procedures, the specimens were scanned again, and the registered preoperative and postoperative cross-section images of the roots (n = 70,030) were screened to identify the presence of dentinal micro-cracks. RESULTS: Overall, dentinal defects were observed in 28,790 cross-section images (41.11%). In the TRUShape, SAF, BioRace, and Reciproc groups, dentinal micro-cracks were visualized in 56.47% (n = 9842), 42.38% (n = 7450), 32.90% (n = 5826), and 32.77% (n = 5672) of the slices, respectively. All dentinal defects observed in the postoperative data sets were already present in the corresponding preoperative images. CONCLUSIONS: None of the preparation systems induced the formation of new dentinal micro-cracks.


Assuntos
Radiografia Dentária , Preparo de Canal Radicular/efeitos adversos , Fraturas dos Dentes/etiologia , Microtomografia por Raio-X , Dentina/lesões , Humanos , Incisivo/lesões , Incisivo/cirurgia , Radiografia Dentária/métodos , Preparo de Canal Radicular/instrumentação , Preparo de Canal Radicular/métodos , Fraturas dos Dentes/dietoterapia , Microtomografia por Raio-X/métodos
17.
J Endod ; 43(3): 462-466, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28131415

RESUMO

INTRODUCTION: The aim of the present study was to evaluate the influence of Blue thermal treatment on the bending resistance and cyclic fatigue of conventional M-Wire Reciproc files (VDW, Munich, Germany). The roughness pattern and the microhardness of the files were also assessed. METHODS: Flexibility of standard Reciproc R25 files and the corresponding Blue prototypes was determined by 45° bending tests according to the ISO 3630-1 specification. Instruments were also subjected to cyclic fatigue resistance, measuring the time to fracture in an artificial stainless steel canal with a 60° angle and a 5-mm radius of curvature. The fracture surface of all fragments was examined with a scanning electron microscope. The roughness of the working parts was quantified by using a profilometer, and the microhardness test was performed using the Vickers hardness tester. Results were statistically analyzed using the Student t test with a level of significance set at P < .05. RESULTS: Reciproc Blue instruments presented a significantly longer cyclic fatigue life and significantly lower bending resistance than the original Reciproc instrument (P < .05). Regarding the roughness pattern, there was no significant difference between Reciproc Blue and the original Reciproc instruments (P > .05), whereas Reciproc Blue revealed significantly lower microhardness than the original Reciproc instrument (P < .05). CONCLUSIONS: Reciproc Blue nickel-titanium showed improved all-around performance when compared with conventional M-Wire superelastic nickel-titanium, demonstrating improved flexibility and fatigue resistance, and reduced microhardness while maintaining similar characteristics of the surface.


Assuntos
Instrumentos Odontológicos , Análise do Estresse Dentário , Estresse Mecânico , Ligas , Desenho de Equipamento , Teste de Materiais
18.
Braz Dent J ; 27(6): 664-669, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27982176

RESUMO

This study aimed to evaluate the cause-effect relationship between canal preparation with ProTaper Universal (PTU) system and dentinal defects formation using micro-computed tomography (micro-CT) analysis. Forty mesial canals of mandibular molars with a type II Vertucci's canal configuration were scanned at an isotropic resolution of 14.16 µm. The sample was assigned to an experimental (n = 30) and a control (n = 10) groups, and the mesial canals were prepared with PTU system up to F2 instrument. The specimens from the experimental group were scanned and the cross-section images of the mesial roots, before and after preparation, were screened to identify the presence of dentinal defects. In the control group, the specimens were sectioned perpendicularly to the long axis of the root into 1-mm-thick slices (n = 80) and examined under optical microscope. Once a dentinal defect was detected, the slice was scanned through micro-CT. In the experimental group, dentinal micro-cracks were observed in 4,828 slices (24.04%). In all cross-section images, dentinal defects identified in the postoperative images were already present in the corresponding preoperative image. In the control group, 13 out of 80 slices (16.25%) had at least one dentinal defect visualized under stereomicroscopy, which was identified after a further micro-CT scanning. Micro-CT showed reliability as similar as optical microscopy in detecting dentinal defects, adding the possibility of tracking the dentinal tissue, before and after canal preparation, and providing a clear visualization of micro-cracks. Root canal preparation with PTU system did not induce the formation of new dentinal defects.


Assuntos
Dentina , Preparo de Canal Radicular/métodos , Causalidade , Humanos , Microtomografia por Raio-X
19.
Braz. dent. j ; 27(6): 664-669, Nov.-Dec. 2016. graf
Artigo em Inglês | LILACS | ID: biblio-828066

RESUMO

Abstract This study aimed to evaluate the cause-effect relationship between canal preparation with ProTaper Universal (PTU) system and dentinal defects formation using micro-computed tomography (micro-CT) analysis. Forty mesial canals of mandibular molars with a type II Vertucci's canal configuration were scanned at an isotropic resolution of 14.16 µm. The sample was assigned to an experimental (n = 30) and a control (n = 10) groups, and the mesial canals were prepared with PTU system up to F2 instrument. The specimens from the experimental group were scanned and the cross-section images of the mesial roots, before and after preparation, were screened to identify the presence of dentinal defects. In the control group, the specimens were sectioned perpendicularly to the long axis of the root into 1-mm-thick slices (n = 80) and examined under optical microscope. Once a dentinal defect was detected, the slice was scanned through micro-CT. In the experimental group, dentinal micro-cracks were observed in 4,828 slices (24.04%). In all cross-section images, dentinal defects identified in the postoperative images were already present in the corresponding preoperative image. In the control group, 13 out of 80 slices (16.25%) had at least one dentinal defect visualized under stereomicroscopy, which was identified after a further micro-CT scanning. Micro-CT showed reliability as similar as optical microscopy in detecting dentinal defects, adding the possibility of tracking the dentinal tissue, before and after canal preparation, and providing a clear visualization of micro-cracks. Root canal preparation with PTU system did not induce the formation of new dentinal defects.


Resumo O objetivo deste estudo foi avaliar a relação de causa-efeito entre o preparo do canal radicular com o sistema ProTaper Universal (PTU) e a formação de defeitos dentinários usando a análise por micro-tomografia computadorizada (micro-CT). Quarenta raízes mesiais de molares inferiores com a configuração tipo II de Vertucci foram escaneadas com resolução isotrópica de 14.16 μm. A amostra foi distribuída em um grupo experimental (n = 30) e um grupo controle (n = 10), e os canais mesiais foram preparados com o sistema PTU até a lima F2. As amostras do grupo experimental foram escaneadas e as imagens de secção transversal das raízes mesiais, antes e após o preparo, foram analisadas ​​para identificar a presença de defeitos dentinários. No grupo controle, os dentes foram seccionados perpendicularmente em relação ao longo eixo da raiz em fatias de 1 mm de espessura (n = 80) e examinados ao microscópio óptico. Uma vez detectado um defeito dentinário, a fatia foi escaneada através da micro-CT. No grupo experimental, defeitos dentinários foram observados em 4.828 secções transversais (24,04%). Em todas as imagens de secção transversal, os defeitos dentinários após os procedimentos experimentais já estavam presentes na secção pré-operatória correspondente. No grupo controle, 13 das 80 fatias (16,25%) apresentaram pelo menos um defeito dentinário visualizado através do microscópio, o qual foi identificado em um escaneamento posterior. A micro-CT mostrou confiabilidade com a microscopia óptica para detecção e visualização dos defeitos dentinários, permitindo acompanhar o tecido dentinário antes e depois do preparo do canal. O preparo do canal radicular com o sistema PTU não induziu a formação de novos defeitos dentinários.


Assuntos
Humanos , Dentina , Preparo de Canal Radicular/métodos , Causalidade , Microtomografia por Raio-X
20.
J Endod ; 42(10): 1540-4, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27663618

RESUMO

INTRODUCTION: Glide path preparation has been recommended as a mandatory clinical step to ensure the safe usage of nickel-titanium (NiTi) rotary instruments. This study aimed to evaluate the effectiveness and fracture rate of 4 pathfinding NiTi rotary instruments in mechanically negotiating moderately curved molar canals. METHODS: Moderately curved maxillary (n = 120) and mandibular (n = 120) molars were randomly distributed into 4 experimental groups (n = 60, 30 maxillary and 30 mandibular molars) according to the instrument used for glide path preparation: ScoutRace 10/.02 (FKG Dentaire, La Chaux-de-Fonds, Switzerland) (800 rpm and 1-Ncm torque), ProDesign 25/.01 (Easy Equipamentos Odontológicos, Belo Horizonte, MG, Brazil) (350 rpm and 1-Ncm torque), Mtwo 10/.04 (VDW, Munich, Germany) (280 rpm and 1.2 Ncm torque), or ProGlider 16/.02 (Dentsply Maillefer, Ballaigues, Switzerland) (300 rpm and 5-Ncm torque). The instrument fracture rate and the absolute and percentage frequencies of molars in which the pathfinding instruments reached the full working length in all root canals according to tooth and canal types were recorded and statistically compared using the Pearson's chi-square test (α = 5%). RESULTS: The highest and lowest frequency of reached the full working length canals were observed in the ScoutRace (68.3%) and ProDesign (38.3%) groups (P < .05), respectively, whereas the Mtwo (58.3%) and ProGlider (51.6%) groups showed intermediate results (P > .05). The ProGlider group showed the highest percentage frequency of instrument separation (11.6%) followed by the Mtwo (8.3%), ScoutRace (3.3%), and ProDesign (3.3%) groups (P < .05). CONCLUSIONS: ScoutRace performed more efficiently and with less instrument breakage than the other systems. ProDesign was the least efficient, and ProGlider exhibited the highest rate of instrument breakage among the systems tested.


Assuntos
Instrumentos Odontológicos , Cavidade Pulpar/anatomia & histologia , Dente Molar/anatomia & histologia , Preparo de Canal Radicular/instrumentação , Ápice Dentário/anatomia & histologia , Ligas Dentárias , Cavidade Pulpar/diagnóstico por imagem , Desenho de Equipamento , Falha de Equipamento , Humanos , Dente Molar/diagnóstico por imagem , Níquel , Titânio , Ápice Dentário/diagnóstico por imagem , Torção Mecânica
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