Effect of different activation methods on the intratubular penetration of CaOH2 paste: Ex-vivo analysis by confocal laser scanning microscopy.

The aim of this study was to evaluate the maximum penetration depth (MPD) and penetration area (PA) of CaOH2 paste agitated by different methods and to measure the pH after performing these methods. Fifty-five mandibular premolars were divided into control, GL and 4 experimental groups, GEC, GXP, GEDDY and GI (n = 11), where the paste was agitated with Easy Clean, XP-endo Finisher, EDDY and Irrisonic, respectively. The canals were instrumented and irrigated with NaOCl. The paste was manipulated with propylene glycol and rhodamine B dye. Root sections were examined using confocal laser scanning microscopy. There was no difference between groups regarding PA (p > 0.05). At 5 mm, MPD was greater in GEC than in GL or GEDDY, and greater in GI than in GL (p < 0.05). At 2 mm, MPD was greater in GEC than in the other groups (p < 0.05). In conclusion, both Easy Clean and Irrisonic promoted deeper paste penetration and were associated with higher pH levels.

Influence of Heat Treatment of Nickel-Titanium Instruments on Cyclic Fatigue Resistance in Simulated Curved Canals.

OBJECTIVE: The aim of this study was to compare the cyclic fatigue of heat-treated and non-treated instruments. MATERIALS AND METHODS: Twenty instruments with and without heat treatment from Bassi Logic were evaluated (n = 10). All instruments were subjected to dynamic cyclic fatigue through continuous rotations inside a stainless-steel tube (1.4-mm diameter, 9-mm curvature with 6-mm radius, and 90° angle) using a custom-made device, which performed 1 axial oscillation every 2 seconds with an amplitude of 3 mm, powered by a torque-controlled motor (Silver Reciproc, VDW, Germany), with speed adjusting to 950 rpm and torque to 4 N, according to manufacturer's guidance. The groups were compared using the Mann-Whitney test. RESULT: The fracture time of the heat-treated instruments (97.20 ± 39.94 second and non-treated instruments (14.30 ± 6.78 seconds had statistical differences [p < 0.05]). Heat-treated instruments were 6.8 times more resistant to fatigue than non-treated instruments (p < 0.05). CONCLUSION: Heat treatment provides increased fatigue resistance of NiTi alloy with the same design.

Impact of Sodium Hypochlorite on Organic Tissue Dissolution in the Periapical Region of Immature Permanent Teeth: An Ex Vivo Study.

INTRODUCTION: The purpose of this study was to evaluate the impact of different sodium hypochlorite (NaOCl) irrigation protocols on organic tissue dissolution in the periapical region of simulated immature permanent teeth. METHODS: Eight single-rooted premolars and 48 samples of porcine palatal mucosa were used. Acrylic resin prototypes were constructed, placing the tissue in close contact with the dental apices. Specimens were then divided into 6 groups (n = 8): 2 control groups of normal saline irrigation with (NS/WA) or without (NS/NA) ultrasonic activation and 4 experimental groups of 1.5% and 2.5% NaOCl irrigation with (NaOCl 1.5%/WA and NaOCl 2.5%/WA) or without (NaOCl 1.5%/NA and NaOCl 2.5%/NA) activation. Root canals were irrigated with 20 mL of the solution for 5 minutes distributed over 4 irrigation cycles. In each cycle, after irrigation, the solution was either kept stagnant or activated for 30 seconds and then replaced. Specimens were weighed on a precision balance before and after the irrigation protocols. Tissue dissolution was measured by the difference between the initial and final weights. One-way analysis of variance was applied followed by the Tukey honestly significant difference test (α = 0.05). RESULTS: The NS/NA and NS/WA groups had mean weight reductions similar to the 1.5% NaOCl/NA group (P > .05) and lower than the others (P < .05). The 2.5% NaOCl/NA and 2.5% NaOCl/WA groups had the highest mean weight loss (P < .05), whereas the 1.5% NaOCl/WA group had intermediate values (P < .05). CONCLUSIONS: Periapical tissue dissolution occurred in all groups, with a greater impact observed with 2.5% NaOCl with or without ultrasonic activation.

Influência do hipoclorito de sódio na resistência à fadiga cíclica em instrumentos rotatórios endodônticos de memória controlada de NiTi: uma avaliação experimental / Influence of sodium hypochlorite on cyclic fatigue resistance in niti controlled memory endodontics rotary instruments: an experimental evaluation

Introdução: É importante saber se o hipoclorito de sódio (NaOCl) influencia a resistência à fadiga cíclica das limas de níquel-titânio (NiTi). Objetivo: Avaliar a influência de NaOCl 2,5% na resistência à fadiga cíclica de dois sistemas de NiTi. Material e método: 40 instrumentos rotatórios - 20 TruNatomy® (TRU, Dentsply Sirona, Maillefer, Ballaigues, Suíça) e 20 Prodesing Logic2® (PDL2, Bassi, Belo Horizonte, Minas Gerais, Brasil) - foram aleatoriamente distribuídos em 4 grupos experimentais (n = 10) imersos em água destilada (H2O) e NaOCl 2,5% em temperatura a 37°C. Foram submetidos a testes de fadiga cíclica mensurando o número de ciclos para fratura (NCF) e análise dessas superfícies pós-teste em microscópio eletrônico por varredura. Para a análise estatística entre os grupos, foi aplicada a análise de variância (ANOVA), complementada com o pós-teste de Tukey. Resultado: Houve diferença estatística em todos os grupos (P<0.05). Os instrumentos PDL2 obtiveram maior resistência à fratura nas condições em H2O e em NaOCl 2,5% comparados aos instrumentos TRU. Na análise de grupos de instrumentos nas soluções de NaOCl e H2O, foi observado que o NaOCl 2,5% diminuiu o NCF. Conclusão: A resistência à fadiga cíclica dos instrumentos TRU e PDL2 diminuiu com NaOCl 2,5%. Os instrumentos PDL2 foram mais resistentes à fratura em relação aos instrumentos TRU.

Introduction: It is important to know whether sodium hypochlorite (NaOCl) influences the cyclic fatigue resistance of nickel-titanium (NiTi) files. Objective: To evaluate the influence of NaOCl 2.5% on the cyclic fatigue resistance of two NiTi systems. Material and method: Forty rotary instruments - 20 TruNatomy® (TRU, Dentsply Sirona, Maillefer, Ballaigues, Switzerland) and 20 Prodesign Logic2® (PDL2, Bassi, Belo Horizonte, Minas Gerais, Brazil) - were distributed randomly across four experimental groups (n=10) and submerged in distilled water (H2O) or 2.5% NaOCl at 37°C according to allocation. Cyclic fatigue testing was then performed, measuring the number of cycles to fracture (NCF), and post-test surfaces were analysed by scanning electron microscopy (SEM). Statistical Analysis: Analysis of variance (ANOVA) was applied for between-group analysis, followed by Tukey's post-hoc test. Result: A significant difference was observed in all groups (P<0.05). PDL2 instruments showed higher fracture resistance under H2O and 2.5% NaOCl conditions compared to TRU. Analysis of all instrument groups showed that exposure to 2.5% NaOCl decreased the NCF compared to H2O. Conclusion: Cyclic fatigue resistance of the TRU and PDL2 instruments was decreased by exposure to 2.5% NaOCl. PDL2 instruments were more resistant to fracture than TRU instruments.

Avaliação da acurácia de quatro localizadores apicais durante o retratamento endodôntico / Evaluate the accuracy of four electronic apex locators during endodontic retreatment

Este estudo teve como objetivo avaliar a acurácia de quatro localizadores apicais eletrônicos durante o retratamento endodôntico. Quarenta pré-molares unirradiculares com apenas um canal, ápice completamente formado, foram divididos em quatro grupos e analisados: Grupo 1: Root ZX ll. Grupo 2: Mini Root. Grupo 3: Propex ll e Grupo 4: Mini Apex. Todos os elementos foram padronizados no comprimento de 22 mm, instrumentados com limas Wave One Primary (25.08), obturados e armazenados. Após um mês, foram desobturados com limas reciprocantes Wave One Primary (25.08) e, em seguida, montados em blocos de esponja vegetal, embebida em solução de cloreto de sódio a 0,9%. A acurácia eletrônica de cada elemento foi realizada, utilizando-se uma lima manual do tipo K#20, até que a mesma fosse ultrapassada pelo forame e recuada até o comprimento real do dente, onde, então, as medidas de cada elemento eram anotadas. Todas as medidas obtidas de cada grupo passaram por análise estatística. Não houve diferença estatisticamente significante entre os localizadores apicais eletrônicos analisados, quando utilizados durante o retratamento endodôntico, sendo possível concluir que, os quatro modelos de localizadores apicais analisados mostraram-se eficientes durante o retratamento endodôntico, dentro dos limites estabelecidos, não havendo diferença entre eles.

This study aimed to evaluate the accuracy of four electronic apex locators during endodontic retreatment. Forty single-rooted premolars, with a root canal, with fully formed apex, were divided into four groups and analyzed: Group 1: Root ZX II. Group 2: Mini Root. Group 3: Propex II and Group 4: Mini Apex. All elements have been standardized in the length of 22 mm, instrumented with Wave One Primary (25.08) files, sealed and stored. After a month, the desobturation with reciprocating Wave One Primaty (25.08) files off and then assembled into blocks vegetable sponge, soaked in 0.9% sodium chloride solution. Electronic accuracy of each element was performed using a manual file type K#20, until it was overtaken by the foramen and retracted to the actual length of the tooth, which then measures each element were noted. All measurements obtained from each group passed by statistical analysis. There was no statistically significant difference between the electronic apex locators analyzed when used during endodontic retreatment it is possible to conclude that the four models analyzed apex locators were effective during endodontic retreatment wirhin the established timits, there is no difference between them.

Micro-Computed Tomographic Evaluation of 2 Nickel-Titanium Instrument Systems in Shaping Root Canals.

INTRODUCTION: Cleaning and shaping without making procedural errors have always been a challenge in endodontics, particularly when the root canals are curved. Several rotary instruments have been developed to minimize such errors. The purpose of this study was to compare the shaping ability of 2 rotary file systems, BioRace (BR; FKG, La Chaux-de-Fonds, Switzerland) and ProTaper Next (PTN; Dentsply Maillefer, Ballaigues, Switzerland), during the preparation of curved root canals in extracted teeth using micro-computed tomographic imaging. METHODS: A total of 20 first and second human mandibular molars with 2 separate mesial canals were scanned before and after root canal preparations using the SkyScan 1176 X-ray microtomograph (Bruker microCT, Kontich, Belgium) at a resolution of 17.42 µm. Canals were prepared using the BR and PTN systems. The percentage of dentin removed after preparation, root canal volume increase, untreated canal walls, structure model index, degree of canal transportation, and centering ability were also measured. RESULTS: There were no significant differences between the 2 groups in the removed dentin after preparation and determination of the root canal volume, percentage of untreated canal walls, structure model index, degree of canal transportation, and centering ability (P > .05). CONCLUSIONS: In conclusion, within the limitations of this ex vivo study, instrumentation of moderately curved mesial roots with 2 independent root canals and foramina using the BR and PTN rotary file systems were equally effective. Both instrumentation systems caused negligible procedural errors with minimal apical transportation.

Efeito do laser de baixa potência na dor após a montagem do aparelho ortodôntico / Effect of low level laser for pain relief after the first orthodontic archwire’s placement

Objetivo: avaliar clinicamente a eficácia da Terapia de Laser de Baixa Potência (TLBP) no alívio da dor após a instalação do aparelho ortodôntico e primeiro arco. Materiais e Métodos: 90 voluntários receberam aparelho fixo e colocação do primeiro arco ortodôntico. Foram randomicamente divididos em três grupos: Grupo 1- Controle (n=30), Grupo 2 - Placebo (n=30) e Grupo 3 - Laser (n=30). Foi realizada a TLBP infravermelho (810 nm) com 100 mW de potência e dose de 6 J/cm2 divididas em quatro aplicações por dente. A dor foi avaliada utilizando Escala Visual Analógica (EVA). Os dados obtidos foram submetidos à análise estatística por meio de teste de Kruskal- Wallis (α=0,05). Resultados: Em todos os grupos analisados a dor iniciou-se após 2 horas, houve um pico de dor entre 12 horas e 48 horas e sua diminuição ocorreu em sete dias. O Grupo 3 (Laser) apresentou todos os valores de dor menores em relação aos valores observados nos outros grupos. Houve diferença estatisticamente significante (p<0,05) da dor pós-operatória entre 12 e 48 horas (momento de pico de dor) para o grupo 3 em relação aos grupos 1 e 2. Conclusão: A TLBP mostrou-se eficiente para a redução da dor após a colocação do aparelho fixo e primeiro arco ortodôntico...

Objective: The aim of this study was to clinically evaluate Low Level Laser Therapy (LLLT) as a method of reducing pain after the first orthodontic archwire placement. Materials and Methods: 90 volunteers received metal braces and the first archwire. They were randomly distributed over three different treatment groups: Group 1- (n=30) Control, patients did not received any LLLT; Group 2- (n=30) Placebo, the LLLT was simulated, the laser was turned off; Group 3- (n=30) Laser patients received LLLT, infra-red with 810 nm wave length and 100 mW power, and it was used 6 J/cm2 as total dose per tooth, divided into four times of 1.5 J/cm2 per 12 seconds per point. Pain intensity experienced was evaluated by a Visual Analogue Scale. Data were tabulated and analyzed through Biostat 4.0 software. Means and standard deviations were calculated and a Kruskal-Wallis statics test was performed (Dunn’s method) (α=0.05). Results: It was possible to observe that the pain started 2 hours after treatment was initiated in the three groups. Higher pain levels occurred between 12 and 48 hours, and pain reduction occurred in 7 days. Group 3 (Laser) presented lower pain data values than the other groups. There was a statistically significant difference (p<0.05) among post operating pain in times T3, T4 and T5 between group 3 and groups 1 and 2. Conclusion: LLLT reduced the pain after orthodontics braces and archwires placement...

Efficiency and effectiveness evaluation of three glass fiber post removal techniques using dental structure wear assessment method.

AIM: This study evaluated the efficiency and effectiveness of three glass fiber post removal techniques. MATERIALS AND METHODS: Forty-five extracted maxillary teeth were endodontically treated and cross-sectioned in thirds. Presence of cementing agent and dental structure wear were assessed by analyzing images taken before luting of glass fiber post and after removal procedure. Teeth were divided into 3 groups: Group 1 - diamond bur + Largo reamer; Group 2 - ultrasonic insert; Group 3 - carbide bur + ultrasonic insert. Time spent on removal procedures, dental structure wear and amount of remaining cement agent were recorded and results submitted to ANOVA, Kruskal Wallis and Tukey-Kramer tests. RESULTS: Group 1 - 16'46", 33.33% and 6.99%; Group 2 - 12'31", 40% and 7.86%; and Group 3 - 10'24", 80% and 8.14%. Group 3 presented the most effective removal of glass fiber posts. CONCLUSION: There was no significant difference in efficiency among the evaluated techniques.

Influence of chemical irrigants on the tensile bond strength of an adhesive system used to cement glass fiber posts to root dentin.

OBJECTIVE: The aim of this study was to evaluate the influence of endodontic irrigants on the tensile bond strength of an adhesive system used to cement glass fiber posts to dentin. STUDY DESIGN: Fifty bovine roots were divided into 5 groups according to the solution used during instrumentation: G1, 0.9% NaCl (control); G2, 1.0% NaOCl; G3, 2.5% NaOCl; G4, 5.25% NaOCl; G5, 2% chlorhexidine gel + 0.9% NaCl. The root canals were obturated with gutta-percha and AH Plus sealer, and the glass fiber posts were cemented with Clearfil SE Bond/RelyX ARC. The specimens were submitted to tensile strength testing and the results were analyzed by analysis of variance. RESULTS: There were no statistically significant differences regarding the irrigant solution factor (P > .70). CONCLUSION: It was concluded that the different irrigant solutions did not affect the tensile bond strength of the fixation system used to cement the intraradicular glass fiber posts to dentin.

Study of the bismuth oxide concentration required to provide Portland cement with adequate radiopacity for endodontic use.

OBJECTIVE: The purpose of this study was to determine the ideal concentration of bismuth oxide in white Portland cement to provide it with sufficient radiopacity for use as an endodontic material (ADA specification #57). STUDY DESIGN: 2-mm thick standardized test specimens of white MTA and of white Portland cement, as controls, and of white Portland cement with the experimental addition of 5%, 10%, 15%, 20%, 25% or 30% of bismuth oxide were radiographed and compared with various thicknesses of pure aluminum, using optic density to determine the observed grayscale levels of radiopacity in a scale ranging from 0 to 255. The data was submitted to ANOVA (p<0.05) and the Ryan-Einot-Gabriel-Welch and Quiot test (REGWQ) for multiple comparison of the means. RESULTS: White Portland cement with 0%, 5%, 10%, 15%, 20%, 25% and 30% of bismuth oxide presented mean readings of 63.3, 95.7, 110.7, 142.7, 151.3, 161.0 and 180.0 respectively. MTA presented a mean reading of 157.3. The readings of MTA and white Portland cement with 15% bismuth oxide did not differ significantly from the reading observed for a thickness of 4 mm of aluminum (145.3), which is considered ideal for a test specimen by ADA specification #57 (2 mm above the thickness of the test specimen). CONCLUSION: White MTA and white Portland cement with 15% bismuth oxide presented the radiopacity required for an endodontic cement.

Selamento de perfusão radicular com MTA / Root perforation sealing with MTA

A finalidade deste trabalho é relatar um caso clínico de selamento de perfuração radicular do elemento 11, proveniente de preparo incorreto para retentor intra-radicular. A remoção do pino foi realizada com auxílio de ultra-som, para que depois fosse feito o selamento com MTA e retratamento endodôntico do caso. Uma curetagem cirúrgica foi necessária para remover o cimento existente extravasado para o periodonto. Posteriormente, um pino de fibra de vidro foi instalado e o caso encaminhado para a confecção de nova coroa. Controles iniciais demonstraram ausência de sinais e sintomas.

This work's purpose is to describe a clinical case of a root perforation sealing in a maxillary incisor, deriving from an incorrect post preparation. The root perforation sealing with MTA and retreatment was done after post removal. The excess of MTA in the periodontal was removed surgically. A fibre post was then installed and the case conducted to finish a new crown. Initial clinical controls indicated no symptom.

Canal mésio-central em primeiro molar inferior / Middle mesial canal of the first mandibular molar

Com o advento da magnificação visual e o aumento da luminosidade proporcionada pela Microscopia Operatória, o clínico vem relatando cada vez mais a incidência de canais que antes acabavam passando desapercebidos e, muitas vezes, levando ao insucesso a terapia endodôntica. Um dos casos que vem despertando a atenção é o de molares inferiores: em sua raiz mesial, entre os habituais canais mésio-vestibular e mésio-lingual, um canal denominado mésio-central vem sendo observado. Este trabalho relata um caso clínico da presença desse canal e faz uma breve revisão de literatura que mostra a incidência do canal mésio-central.