Influence of dental bleaching on the pulp tissue: A systematic review of in vivo studies.

BACKGROUND: Although several studies indicate the harmful effects of bleaching on pulp tissue, the demand for this procedure using high concentrations of hydrogen peroxide (HP) is high. OBJECTIVES: To investigate the influence of bleaching on the pulp tissue. METHODS: Electronic searches were conducted (PubMed/MEDLINE, Scopus, Cochrane Library and grey literature) until February 2021. Only in vivo studies that evaluated the effects of HP and/or carbamide peroxide (CP) bleaching gels on the inflammatory response in the pulp tissue compared with a non-bleached group were included. Risk of bias was performed according to a modified Methodological Index for Non-Randomized Studies scale for human studies and the Systematic Review Centre for Laboratory Animal Experimentation's RoB tool for animal studies. Meta-analysis was unfeasible. RESULTS: Of the 1311 studies, 30 were eligible. Of these, 18 studies evaluated the inflammatory response in animal models. All these studies reported a moderate-to-strong inflammatory response in the superficial regions of pulp, characterized by cell disorganization and necrotic areas, particularly during the initial periods following exposure to 35%-38% HP, for 30-40 min. In the evaluation of human teeth across 11 studies, seven investigated inflammatory responses, with five observing significant inflammation in the pulp of bleached teeth. In terms of tertiary dentine deposition, 11 out of 12 studies noted its occurrence after bleaching with 35%-38% HP in long-term assessments. Additionally, three studies reported significant levels of osteocalcin/osteopontin at 2 or 10 days post-treatment. Other studies indicated an increase in pro-inflammatory cytokines ranging from immediately up to 10 days after bleaching. Studies using humans' teeth had a low risk of bias, whereas animal studies had a high risk of bias. DISCUSSION: Despite the heterogeneity in bleaching protocols among studies, High-concentrations of HP shows the potential to induce significant pulp damage. CONCLUSIONS: High-concentrations of bleaching gel increases inflammatory response and necrosis in the pulp tissue at short periods after bleaching, mainly in rat molars and in human incisors, in addition to greater hard tissue deposition over time. However, further well-described histological studies with long-term follow-up are encouraged due to the methodological limitations of these studies. REGISTRATION: PROSPERO (CRD42021230937).

Morphological alterations of the apical foramen after foraminal enlargement: a systematic review of ex vivo studies / Alterações morfológicas do forame apical após ampliação foraminal: uma revisão sistemática de estudos ex vivo

Foraminal enlargement has been recommended to optimize the disinfection of infected root canals, although some authors still claim that the foramen should be kept in its original shape and position. This study aimed to evaluate morphological alterations of apical foramen after foraminal enlargement through a systematic review. An electronic search was conducted until April 2022. Ex vivo studies evaluating influence of foraminal enlargement in the morphologic changes of apical foramen were included. Studies without a control group or available full text were excluded. Foraminal deformation and area increase were considered as primary outcomes. Risk-of-bias assessment was performed according to a modified Joanna Briggs Institute's Checklist. From 702 studies retrieved, five were eligible. Most studies used single-rooted teeth, and rotary systems for instrumentation ranging from ­ 2 mm to + 1 mm to the apex. All studies found increased major foramen deformation after foraminal enlargement. Among four studies that evaluated foraminal area, all found increased area after foraminal enlargement. Insufficient data for touched/untouched walls by instruments and dentinal microcrack formation was observed. A low risk of bias was found. Foraminal enlargement during root canal preparation seems to increase deformation and major apical foramen area. Future investigations with standardized methodologies are encouraged (AU)

A ampliação foraminal tem sido recomendada para otimizar a desinfecção de canais radiculares infectados, embora alguns autores ainda afirmem que o forame deve ser mantido em sua forma e posição originais. Este estudo teve como objetivo avaliar alterações morfológicas do forame apical após ampliação foraminal por meio de uma revisão sistemática. Uma busca eletrônica foi realizada até abril de 2022. Foram incluídos estudos ex vivo que avaliaram a influência da ampliação foraminal nas alterações morfológicas do forame apical. Foram excluídos estudos sem grupo controle ou com texto completo indisponível. A deformação foraminal e o aumento da área foram considerados desfechos primários. A avaliação do risco de viés foi realizada de acordo com uma lista de verificação modificada do Instituto Joanna Briggs. Dos 702 registros recuperados, cinco foram elegíveis. A maioria dos estudos utilizou dentes unirradiculares e sistemas rotatórios para instrumentação, com comprimento de trabalho variando de ­ 2 mm a + 1 mm até o ápice. Todos os estudos encontraram aumento da deformação do forame maior após ampliação foraminal. Dos quatro estudos que avaliaram a área foraminal, todos encontraram aumento de área após alargamento foraminal. Foram observados dados insuficientes para paredes tocadas/intocadas pelos instrumentos e formação de microfissuras dentinárias. Um baixo risco de viés foi encontrado. A ampliação foraminal durante o preparo do canal radicular parece aumentar a deformação e a área do forame apical. Futuras investigações com metodologias padronizadas são incentivadas (AU)

Comparison between immediate and delayed post space preparations: a systematic review and meta-analysis.

OBJECTIVES: This systematic review and meta-analysis compared the effects of immediate and delayed post space preparation on apical sealing. MATERIALS AND METHOD: Two independent authors conducted a systematic search (PubMed/Medline, Cochrane Library, and other databases, until February 2020) and a risk of bias evaluation. Only in vitro studies that compared the effects of immediate and delayed post space preparations on apical filling and adhesion of the post were eligible. RESULT: Of the 742 articles retrieved, 32 were included. Most of the studies used single-rooted human teeth and rotary files for root canal preparation, a single-cone technique for the filling protocol, and rotary instruments for post space preparation. Various delayed preparation times were evaluated: 8-72 h, 5-30 days (mainly 7 days), and 4 months. In nine studies, the delayed groups showed more apical leakage, while four studies reported more leakage in the immediate groups; ten studies found no significant difference. One study found more bacterial penetration in the delayed group, whereas three studies showed no significant difference. One study reported more voids in the delayed group, while another found no such difference. Three studies showed better post-bond strength in the delayed group, one in the immediate group, whereas three found no significant difference in post-bond strength. Three studies employing varied sealers for root canal fillings were considered for meta-analysis. Two subgroup analyses were also performed (one concerning the use of resin-based sealers (AH Plus), another for zinc oxide-eugenol-based sealers). The results of the meta-analysis showed that a delayed post space preparation led to a significantly higher apical leakage than an immediate preparation (mean difference = 0.41 mm, confidence interval = 0.24-0.59, p < 0.001). CONCLUSION: Delayed post space preparation seems to negatively influence apical sealing; however, further studies are needed to determine the influence of the timing of post space preparation on the other parameters. CLINICAL RELEVANCE: Immediate post space preparation may be the safest clinical choice to prevent apical leakage.

Comparative analysis of torque and apical force to assess the cutting behaviour of ProTaper Next and ProTaper Universal endodontic instruments.

This study assessed the cutting properties of two Nickel Titanium file systems with different designs and manufacturing materials. ProTaper Next X1 and X2 (PTN; Dentsply Sirona) and ProTaper Universal S2 and F1 (PTU; Dentsply Sirona) instruments were employed. The cutting parameters, that is torque and apical forces, were determined using a specially designed bench-testing machine. Dimensional and geometric parameters were considered to evaluate the results. The average maximum torque values showed statistically significant differences (P < 0.05) among all instruments. Apical force for PTN X2 and PTU F1 instruments initially decreased and then experienced a rapid increase in the last 2 mm of the canal. For PTN X1 and PTU S2, apical force increased during the entire test. When compared to PTU files, PTN required higher torque and apical forces during the shaping procedure. The results lead us to conclude that PTN instruments demonstrated a lower cutting efficiency than PTU.

Structural Characteristics and Torsional Resistance Evaluation of WaveOne and WaveOne Gold Instruments after Simulated Clinical Use.

INTRODUCTION: The aim of this study was to compare 2 reciprocating nickel-titanium systems with different manufacturing characteristics and to evaluate the influence of simulated clinical use on their torsional resistance. METHODS: New 25/.08 WaveOne Primary (WO; Dentsply Sirona, York, PA) and 25/.07 WaveOne Gold Primary (Dentsply Sirona) files were used in this study. The diameter and cross-sectional area at 3 mm from the tip were measured using image analyses. The alloy microstructure was evaluated by X-ray diffraction and the phase transformation temperatures by differential scanning calorimetry analyses. Forty files were divided into 4 groups: control group 1 and control group 2, which were submitted to torsion tests until rupture, and experimental group 1 and experimental group 2, in which instruments were used to shape 2 mesial canals of an extracted mandibular molar and then submitted to torsion tests until rupture. RESULTS: WO had higher values of diameter and area at 3 mm from the tip. X-ray diffraction analysis presented R-phase and austenite for both systems. Austenite finish temperatures, determined by differential scanning calorimetry, were above room temperature. WO showed higher values of torque until rupture, and WaveOne Gold showed higher values of angular deflexion (P > .05). No differences were found between the same type of instrument in the control and experimental groups. CONCLUSIONS: The higher torsional resistance of WO can be attributed to geometric characteristics. The use in 1 tooth with curved canals is safe and does not affect the torsional resistance of the instruments analyzed.

Cyclic flexural fatigue resistance of NiTi Controlled Memory and Blue Technology instruments after torsional preloading.

Objective The aim of this study was to evaluate the influence of torsional preloading on the cyclic flexural fatigue resistance of thermally treated NiTi instruments. Material and Methods Ten new instruments New Hyflex CM (HF 30.06; Coltene/Whaladent Inc.), Typhoon CM (TYP 30.06; Clinician's Choice Dental Products) and Vortex Blue (VB 30.06; Dentsply Tulsa Dental) were chosen, based on geometry and specific characteristics of the manufacturing process. The new instruments of each system were tested in a bench device to determine their fatigue resistance through mean value of number of cycles to failure (Nf) (Control Group - CG). Another group of 10 new HF, TYP and VB instruments were submitted to 20 cycles of torsional straining between 0° and 180° (Experimental Group - EG) and then submitted to fatigue until rupture under the same conditions of the CG. Tested instruments were examined by scanning electron microscopy (SEM). Data were analyzed using one-way analysis of variance and post hoc Tukey's test (α=.05). Results Higher fatigue resistance was accomplished by HF instruments, followed by VB and TYP (p<0.05). During the torsional preloading, the lowest mean torque value was observed for TYP instruments (p<0.05). The torsional preload caused a significant reduction in the Nf values (p<0.05) of about 20%, 39% and 45% for instruments HF, VB and TYP, respectively. Longitudinal cracks, generated during the torsional preloading, were present in VB files, but were not observed in the CM instruments (HF and TYP). Conclusions In conclusion, the flexural fatigue resistance of thermally treated instruments is diminished after cyclic torsional loading.

Cyclic flexural fatigue resistance of NiTi Controlled Memory and Blue Technology instruments after torsional preloading

Abstract Objective The aim of this study was to evaluate the influence of torsional preloading on the cyclic flexural fatigue resistance of thermally treated NiTi instruments. Material and Methods Ten new instruments New Hyflex CM (HF 30.06; Coltene/Whaladent Inc.), Typhoon CM (TYP 30.06; Clinician's Choice Dental Products) and Vortex Blue (VB 30.06; Dentsply Tulsa Dental) were chosen, based on geometry and specific characteristics of the manufacturing process. The new instruments of each system were tested in a bench device to determine their fatigue resistance through mean value of number of cycles to failure (Nf) (Control Group - CG). Another group of 10 new HF, TYP and VB instruments were submitted to 20 cycles of torsional straining between 0° and 180° (Experimental Group - EG) and then submitted to fatigue until rupture under the same conditions of the CG. Tested instruments were examined by scanning electron microscopy (SEM). Data were analyzed using one-way analysis of variance and post hoc Tukey's test (α=.05). Results Higher fatigue resistance was accomplished by HF instruments, followed by VB and TYP (p<0.05). During the torsional preloading, the lowest mean torque value was observed for TYP instruments (p<0.05). The torsional preload caused a significant reduction in the Nf values (p<0.05) of about 20%, 39% and 45% for instruments HF, VB and TYP, respectively. Longitudinal cracks, generated during the torsional preloading, were present in VB files, but were not observed in the CM instruments (HF and TYP). Conclusions In conclusion, the flexural fatigue resistance of thermally treated instruments is diminished after cyclic torsional loading.

Evaluating the cutting efficiency of NiTi instruments with reciprocating motions / Avaliação da eficiência de corte de instrumentos NiTi com movimento reciprocante

Aim:This study tested a setup for in vitro experimental analysis of axial forces and torque during the preparation of artificial canals using nickel-titanium reciprocating endodontic files.Methods: The cutting efficiency of Reciproc (RC) and WaveOne (WO) reciprocating size 25/.08 instruments (n = 10) was evaluated, taking into account their dimensional and geometrical features. Measurements of the diameter at each millimeter from the tip, pitch length, helical angle, and cross-sectional design and area were assessed. Cutting efficiency tests were carried out on a specific bench device by measuring the torque and axial force required during artificial canal shaping. Statistical analysis was performed using one-way ANOVA (α = 0.05). Results:The WO samples showed larger A3 mean values than did the RC instruments (p < 0.0001), despite having equal diameters at 3mm from the tip (D3) (p = 0.521). The mean values of pitch length were higher for RC than for WO instruments (p< 0.0001), with consequently smaller helical angles (p < 0.0001). For the cutting efficiency tests, the required torque was lower for the RC group when compared to the WO group, but it was significant only in the first stage of insertion in the artificial canals (p = 0.008). Regarding the apical force, the RC instruments reached higher values when compared to the WO instruments (p = 0.04) in the second stage of cutting action. Conclusion: Reciproc instruments demonstrated statistically higher cutting efficiency when compared to WaveOne instruments.

Objetivo: Este estudo testa uma configuração para análise experimental in vitro de forças axiais e torque durante o preparo de canais artificiais usando instrumentos endodônticos reciprocantes de níquel-titânio. Métodos: Foi avaliada a eficiência de corte dos instrumentos reciprocantes tamanho 25 / 0,08 (n = 10) Reciproc (RC) e WaveOne (WO), levando em consideração suas características dimensionais e geométricas. Medidas do diâmetro a cada milímetro a partir da ponta, comprimento de pitch, ângulo helicoidal e desenho da área transversal e área foram avaliados. Testes de eficiência de corte foram realizados em um dispositivo de bancada específico, medindo-se o torque e a força axial exigidos durante a modelagem de canais artificiais. A análise estatística foi feita com ANOVA one-way (α = 0,05). Resultados: As amostras de WO mostraram valores médios A3 maiores do que os instrumentos RC (p <0,0001), apesar de terem diâmetros iguais a 3 mm da ponta (D3) (p = 0,521). Os valores médios do comprimento do pitch foram maiores para o RC do que para os instrumentos do WO (p < 0,0001), com consequentemente menores ângulos helicoidais (p < 0,0001). Para os testes de eficiência de corte, o torque necessário foi menor para o grupo RC em comparação com o grupo WO, mas significativo apenas no primeiro estágio de inserção nos canais artificiais (p = 0,008). Em relação à força apical, os instrumentos RC alcançaram valores maiores em relação aos instrumentos WO (p = 0,04) no segundo estágio de corte. Conclusão: Os instrumentos Reciproc demonstraram uma eficiência de corte estatisticamente superior em comparação com os instrumentos WaveOne.

Influence of Cyclic Flexural Deformation on the Torsional Resistance of Controlled Memory and Conventional Nickel-titanium Instruments.

INTRODUCTION: The aim of this study was to evaluate the influence of cyclic deformation on the torsional resistance of controlled memory (CM) nickel-titanium files in comparison with superelastic (SE) instruments with similar geometric and dimensional characteristics. METHODS: New 30/.06 HyFlex (HF; Coltene/Whaledent, Inc, Cuyahoga Falls, OH), Typhoon (Clinician's Choice Dental Products, New Milford, CT), RaCe (FKG, La-Chaux De Fonds, Switzerland), and ProTaper Universal F2 instruments (F2; Dentsply Maillefer, Ballaigues, Switzerland) were assessed. The diameter and pitch length were measured along the active part of the instruments. The number of cycles to failure (Nf) in flexural fatigue and the torsional resistance were evaluated for new files (n = 10). Ten new instruments of each type were fatigued to 3/4 of their fatigue life and then submitted to torsion until rupture. Data were analyzed using 1-way analysis of variance (α = .05). RESULTS: New CM files had a significantly higher Nf when compared with SE instruments; HF exhibited the highest value (P = .001). The mean torque value for F2 was the highest (P = .001). CM files precycled to 3/4 Nf had a significantly lower torque than the new files (HF: P = .003, Typhoon: P = .001), whereas the SE instruments displayed no significant differences (F2: P = .059, RaCe: P = .079). CONCLUSIONS: Cyclic flexural loading significantly reduced the torsional resistance of CM instruments.

The impact of clinical use on the torsional behavior of Reciproc and WaveOne instruments.

OBJECTIVE: The aim of this study was to assess the influence of clinical use, in vivo, on the torsional behavior of Reciproc and WaveOne instruments considering the possibility that they degraded with use. MATERIAL AND METHODS: Diameter at each millimeter, pitch length, and area at 3 mm from the tip were determined for both types of instruments. Twenty-four instruments, size 25, 0.08 taper, of each system were divided into two groups (n=12 each): Control Group (CG), in which new Reciproc (RC) and WaveOne Primary (WO) instruments were tested in torsion until rupture based on ISO 3630-1; and Experimental Group (EG), in which each new instrument was clinically used to clean and shape the root canals of one molar. After clinical use, the instruments were analyzed using optical and scanning electron microscopy and subsequently tested in torsion until fracture. Data were analyzed using one-way analysis of variance at a=.05. RESULTS: WO instruments showed significantly higher mean values of cross-sectional area A3 (P=0.000) and smaller pitch lengths than RC instruments with no statistically significant differences in the diameter at D3 (P=0.521). No significant differences in torsional resistance between the RC and WO new instruments (P=0.134) were found. The clinical use resulted in a tendency of reduction in the maximum torque of the analyzed instruments but no statistically significant difference was observed between them (P=0.327). During the preparation of the root canals, two fractured RC instruments and longitudinal and transversal cracks in RC and WO instruments were observed through SEM analysis. CONCLUSION: After clinical use, no statistically significant reduction in the torsional resistance was observed.

Enhancement of NiTi superelastic endodontic instruments by TiO2 coating.

Rotary nickel-titanium (NiTi) endodontic instruments were coated with a nanometric flexible TiO2 layer through dip-coating sol-gel. Control groups and coated samples of superelastic NiTi instruments model RaCe 25/0.06 (0.25mm tip-diameter, 6% conicity) were comparatively investigated with respect to the cutting efficiency, fatigue life, and corrosion resistance. Results showed an improvement in cutting efficiency for the coated samples and a high resistance to corrosion in NaClO. The coated instruments showed a better performance in fatigue life after corrosion.

The impact of clinical use on the torsional behavior of Reciproc and WaveOne instruments

ABSTRACT Torsional overload is a fracture representative parameter for instruments in single-file techniques. Objective The aim of this study was to assess the influence of clinical use, in vivo, on the torsional behavior of Reciproc and WaveOne instruments considering the possibility that they degraded with use. Material and Methods Diameter at each millimeter, pitch length, and area at 3 mm from the tip were determined for both types of instruments. Twenty-four instruments, size 25, 0.08 taper, of each system were divided into two groups (n=12 each): Control Group (CG), in which new Reciproc (RC) and WaveOne Primary (WO) instruments were tested in torsion until rupture based on ISO 3630-1; and Experimental Group (EG), in which each new instrument was clinically used to clean and shape the root canals of one molar. After clinical use, the instruments were analyzed using optical and scanning electron microscopy and subsequently tested in torsion until fracture. Data were analyzed using one-way analysis of variance at a=.05. Results WO instruments showed significantly higher mean values of cross-sectional area A3 (P=0.000) and smaller pitch lengths than RC instruments with no statistically significant differences in the diameter at D3 (P=0.521). No significant differences in torsional resistance between the RC and WO new instruments (P=0.134) were found. The clinical use resulted in a tendency of reduction in the maximum torque of the analyzed instruments but no statistically significant difference was observed between them (P=0.327). During the preparation of the root canals, two fractured RC instruments and longitudinal and transversal cracks in RC and WO instruments were observed through SEM analysis. Conclusion After clinical use, no statistically significant reduction in the torsional resistance was observed.

Constant Insertion Rate Methodology for Measuring Torque and Apical Force in 3 Nickel-Titanium Instruments with Different Cross-sectional Designs.

INTRODUCTION: The aim of this study was to evaluate the cutting characteristics of 3 nickel-titanium instruments with different cross-sectional designs using a recently developed methodology. METHODS: Insertion tests at a constant rate of 5.4 mm/min were performed on a bench test device by measuring the torque and apical force required for penetrating prefabricated acrylic blocks containing an artificial canal preflared with #10 and #15 K-files. Size 20/.06 Mtwo (VDW, Munich, Germany) and RaCe (FKG, La-Chaux De Fonds, Switzerland) instruments, together with ProTaper Universal (PTU) F1 instruments (Dentsply Maillefer, Ballaigues, Switzerland) (10 instruments of each type), were tested using an endodontic motor set at 300 rpm and 5 N·cm. The instruments were characterized with respect to the pitch length, rake angle, and cross-sectional area. Statistical analysis was performed with analysis of variance (α = 0.05). RESULTS: The torque was significantly lower for Mtwo compared with the other 2 groups (P < .05). It was also lower for RaCe in comparison with PTU F1 (P < .05). Regarding the apical force, the RaCe instruments had lower values when compared with the Mtwo and PTU F1 instruments (P < .05). There was no statistically significant difference between the PTU F1 and Mtwo instruments (P > .05). CONCLUSIONS: The methodology allowed the cutting properties of the instruments to be assessed in terms of their different geometric characteristics. The cross-sectional design, especially in Mtwo instruments with 2 sharp edges and great chip removal capability, was a differential factor for their higher cutting action.

Resistência à fadiga de instrumentos rotatórios ProTaper Universal após o uso com e sem movimento de pressão lateral / Fatigue resistance of rotary ProTaper Universal instruments after use with and without lateral pressure motion

Objetivo: Avaliar a resistência à fadiga de instrumentos rotatórios ProTaper Universal após múltiplos usos clínicos com e sem movimento de pressão lateral. Material e Métodos: Trinta conjuntos de instrumentos ProTaper Universal (PTU) (Dentsply-Maillefer, Ballaigues, Suíça), calibres S1, S2, F1 e F2, em um total de 120 instrumentos, foram analisados e divididos em três grupos: Grupo com Pressão Lateral (PL), com 10 conjuntos de instrumentos, cada conjunto usado clinicamente em cinco molares inferiores e superiores (15 a 20 canais) utilizando os instrumentos de formatação com movimento de pressão lateral; e Grupo Sem Pressão Lateral (SPL), com 10 conjuntos de instrumentos, cada conjunto usado clinicamente em cinco molares inferiores e superiores (15 a 20 canais), utilizando os instrumentos de formatação sem movimento de pressão lateral. Os instrumentos dos grupos PL e SPL foram posteriormente testados em fadiga até a ruptura, juntamente com 10 conjuntos de instrumentos novos do Grupo Controle (GC). Os dados foram analisados por meio de análise de variância (α = 0,05). Resultados: Múltiplos usos clínicos causaram uma redução na vida em fadiga dos instrumentos analisados. Quando o efeito de se utilizar o movimento de pressão lateral com os instrumentos de formatação foi avaliado, houve uma tendência para o consumo da vida em fadiga ser maior para os instrumentos de S1 e S2 em PL e observou-se o mesmo para os instrumentos F1 e F2 no grupo SPL. Conclusão: O uso do movimento de pressão lateral com os instrumentos PTU S1 e S2 durante a formação de canais radiculares curvos tendeu a diminuir o consumo de vida em fadiga dos instrumentos F1 e F2. Descritores: Endodontia. Tratamento do canal radicular. Instrumentos odontológicos.

Eficiência de corte de diferentes sistemas endodônticos de NiTi / Cutting efficiency of rotary NiTi instruments

As características geométricas dos instrumentos de NiTi influenciam diretamente a sua eficiência de corte. Neste estudo avaliou-se o corte de instrumentos rotatórios de NiTi de calibre 20, taper .06, dos sistemas EndoSequence (ES), Mtwo, GT, GTX, K3, RaCe e ProTaper F1 (F1). Inicialmente, os instrumentos foram caracterizados com relação ao diâmetro da parte ativa, geometria da seção transversal e ãngulos helocoidais e de corte. Os ensaios de eficiência de corte foram realizados em dispositivo de bancada, onde 5 instrumentos de cada tipo foram testados em blocos de acrílico pré-fabricados, contendo um canal artificial previamente explorado com limas manuais #10 e #15...

Cleaning the apical third of curved canals after different irrigation protocols.

This study evaluated the protocols of sonic and vacuum irrigation regarding the capacity of debris removal from root canal systems. Canal preparations were carried out on 30 mandibular first molars using the ProTaper Universal System. Teeth were divided into two experimental groups (n=15): Group 1: sonic irrigation and Group 2: vacuum irrigation protocol. Subsequently, the mesial roots were sectioned and observed by stereomicroscopy and scanning electron microscopy. Three independent examiners evaluated images of the apical thirds according to the following scores: 1= small presence of debris, 2= moderate presence of debris, and 3= dense presence of debris. Data were analyzed with ANOVA and Kruskal-Wallis tests (α=0.05). Comparison among the groups revealed that at the apical third, the root halves of Group 1 had significantly less surface debris (p=0.002) than those of Group 2. However, at 2 mm from the working length, Group 2's specimens showed less remaining debris in approximately 75% of the analyzed root canals. At the whole apical third, the sonic irrigation protocol removed significantly more debris than the vacuum protocol. However, in the region at 2 mm from the working length, the second irrigation method demonstrated a better performance.

Cleaning the apical third of curved canals after different irrigation protocols

This study evaluated the protocols of sonic and vacuum irrigation regarding the capacity of debris removal from root canal systems. Canal preparations were carried out on 30 mandibular first molars using the ProTaper Universal System. Teeth were divided into two experimental groups (n=15): Group 1: sonic irrigation and Group 2: vacuum irrigation protocol. Subsequently, the mesial roots were sectioned and observed by stereomicroscopy and scanning electron microscopy. Three independent examiners evaluated images of the apical thirds according to the following scores: 1= small presence of debris, 2= moderate presence of debris, and 3= dense presence of debris. Data were analyzed with ANOVA and Kruskal-Wallis tests (α=0.05). Comparison among the groups revealed that at the apical third, the root halves of Group 1 had significantly less surface debris (p=0.002) than those of Group 2. However, at 2 mm from the working length, Group 2's specimens showed less remaining debris in approximately 75% of the analyzed root canals. At the whole apical third, the sonic irrigation protocol removed significantly more debris than the vacuum protocol. However, in the region at 2 mm from the working length, the second irrigation method demonstrated a better performance.

Este estudo avaliou protocolos de irrigação sônica e a vácuo em relação à capacidade de remoção de debris do sistema de canais radiculares. Trinta primeiros molares mandibulares tiveram seus canais radiculares preparados pela utilização do Sistema ProTaper Universal. Os dentes foram divididos em dois grupos experimentais (n=15): Grupo 1: protocolo de irrigação sônica, e Grupo 2: protocolo de irrigação a vácuo. Posteriormente, as raízes mesiais foram seccionadas e observadas em lupa estereoscópica e microscopia eletrônica de varredura. Três examinadores independentes avaliaram as imagens do terço apical de acordo com as seguintes pontuações: 1. pequena presença de debris; 2: moderada presença de debris; e 3. densa presença de debris. Os dados foram analisados pelos testes estatísticos ANOVA e Kruskal-Wallis (α=0,05). A comparação entre os grupos revelou que, no terço apical, as hemissecções radiculares do Grupo 1 apresentaram debris remanescentes de forma significativamente menor (p=0,002) do que as do Grupo 2. No entanto, a 2 mm do comprimento de trabalho, as amostras do Grupo 2 mostraram menos debris remanescentes em aproximadamente 75% dos canais radiculares analisados. Considerando todo o terço apical, o protocolo de irrigação sônica removeu significativamente mais debris do que o protocolo de irrigação a vácuo. No entanto, na região a 2 mm do comprimento de trabalho, o segundo método de irrigação demonstrou um melhor desempenho.