Este estudo se propõe a analisar a resposta pulpar de dentes humanos a preparos cavitários de classe V, em função de duas diferentes técnicas de instrumentação e de duas diferentes técnicas de restauração. Para tal, cavidades classe V, nas superfícies vestibulares de 48 pré-molares hígidos de pacientes entre 11 e 25 anos, que estavam em tratamento ortodôntico, foram preparadas e restauradas de acordo com os seguintes grupos experimentais: G 1 (n=24) - preparos cavitários realizados com ponta diamantada em alta rotação, restaurados com guta-percha plastificada, cimento ionômero de vidro e verniz cavitário (G 1A; n=12) ou com técnicas adesivas (sistema restaurador adesivo aplicando-se o condicionamento ácido total) e cimento ionômero de vidro (G 1B; n=12); G 2 (n=24) - preparos cavitários com ponta CVD ativada por ultrassom, restaurados com gutapercha plastificada, cimento ionômero de vidro e verniz cavitário (G 2A; n=12) ou com técnicas adesivas (sistema restaurador adesivo aplicando-se o condicionamento ácido total) e cimento ionômero de vidro (G 2B; n=12); e G 3 (controle; n=4) - dentes que foram extraídos sem a realização de qualquer procedimento. Os preparos cavitários foram realizados mantendo o assoalho da cavidade o mais próximo possível da polpa, no entanto, sem provocar exposição pulpar. Os dentes foram extraídos após três períodos experimentais (imediato, sete e trinta dias após o preparo cavitário), fixados, descalcificados, e processados histologicamente. Cortes teciduais longitudinais seriados de 5 m foram obtidos, corados pelas técnicas de H & E e de Brown & Brenn, e examinados em microscopia ótica. As avaliações morfométricas e por escores foram realizadas e os resultados das mesmas, submetidos, respectivamente, aos testes estatísticos de Mann-Whitney e de Kruskal-Wallis/Dunn, adotando-se um nível de significância de 5%. No período inicial, todos os grupos experimentais (1A, 1B, 2A e 2B) exibiram ligeiro desarranjo da camada odontoblástica vacuolizada e leve invasão da zona acelular de Weil. Não houve diferença entre os grupos experimentais iniciais e o grupo controle. No intervalo de sete dias, pôde-se observar redução da camada odontoblástica, muitos núcleos de odontoblastos aspirados nos túbulos dentinários, alguns espécimes com ausência de pré-dentina e resposta inflamatória aguda com hemorragia. Trinta dias depois, cinco espécimes do total avaliado apresentaram dentina terciária; dois espécimes do grupo 1B apresentaram necrose relacionada com a presença de bactérias nos túbulos dentinários; e os demais mostraram graus variados de inflamação crônica, associados a restaurações adesivas ou a processos de reparo, com proliferação de vasos e persistência de focos de hemorragia. Portanto, os dois tipos de instrumentação cavitária promovem respostas pulpares similares entre si, mas as diferentes técnicas restauradoras promovem efeitos significativamente diferentes sobre o complexo dentinopulpar. / The aim of this study is to analyze the pulp response of human teeth to class V cavity preparation, in function of two different instrumentation and restorative techniques. Class V cavities were made on the buccal surfaces of 48 sound human pre-molars from orthodontic patients from 11 to 25 years, and were divided as follows: G1 (n=24) cavity preparations were made with diamond bur under high speed, restored with either plasticized gutta-percha, glass ionomer cement and surface coated with varnish (G1A) or adhesive protocol (total etch technique and adhesive system application) with glass ionomer filling (G1B); G2 (n=24) cavity preparations were made with diamond CVD point and ultrasonic device, restored with either plasticized gutta-percha, glass ionomer cement and surface coated with varnish (G2A) or adhesive protocol (total etch technique and adhesive system application) with glass ionomer filling (G2B); and control group G3 (n=4) extracted teeth with no previous cavity preparation. All avities were prepared with the cavity floor as close to the pulp as possible, without causing pulp exposure. Teeth extractions were made in three experimental periods (immediate, 7 and 30 days after cavity preparation) and right after extraction they were submitted to histological procedures. Longitudinal tissue serial sections of 5 mm were obtained, H&E and Brown&Brenn stained, and analyzed under optical microscope. Morphometric and score evaluations were carried out and data from both were, respectively, submitted to Mann-Whitney and Kruskal-Wallis/Dunn tests, with 5% significance. Immediately, all experimental groups (1A, 1B, 2A and 2B) exhibited a discrete disorganization of the odontoblastic layer and invasion of the Weil zone. There was no difference between experimental and control groups. At 7-day interval, a decrease of the odontoblastic layer was observed. Many odontoblasts nucleus were seen displaced into the dentinal tubules. Some specimens showed absence of pre-dentine and inflammatory pulp response with hemorrhage. Thirty days later, five specimens presented tertiary dentin formation; two specimens from group 1B presented necrosis coincident with bacteria inside the dentinal tubules; the other specimens showed various degrees of chronic inflammation, associated to adhesive restorations or repair processes, with blood vessels proliferation and persistent hemorrhagic areas. Therefore, both instrumentation techniques promoted similar pulp response, but different restoration procedures elicited significantly different responses of the dentinpulp complex.

Made available in DSpace on 2017-07-24T19:22:12Z (GMT). No. of bitstreams: 1 Miguel Munoz Perez.pdf: 2838722 bytes, checksum: 47bde0e445ce247501fdda653ceefbb2 (MD5) Previous issue date: 2010-02-25 / The aim of this study was to evaluate with the finite element method (MEF), the stress distribution under simulated functional loading in different cavity preparations using the pulp chamber of an endodontically-treated second mandible left molar to observe the stability and retention of the Endocrown. Computer tomography data of the tooth was obtained to generate a 3D volumetric model. In this 3D digital tooth, different cavity preparations without (Wo) and with (W) cusp coverage were modeled and edited, as well as a restoration and luting layer. All cavity preparations with cusp coverage had a mesio-occlusal-distal extension. To obtain the Poisson ratio and the elastic modulus of the restorative material used in the MEF, ceramic specimens were subjected to flexural tests. The following groups were obtained according to the cavity preparation: intact tooth (control) [IT]; occlusal-distal extension [WoOD], mesioocclusal- distal extension [WoMOD]; with buccal cusp coverage [WB], with lingual cusps coverage [WL]; with coverage of all cusps [WT]; and remnant of 2 mm above of the cement-enamel junction [Rm]. All groups were subjected to a 200 N loading in the Ansys Workbench v12 software and the stress distribution was analyzed by Rankine principal stresses criteria. "None" experimental group simulated stress distribution as the "IT". "WoOD" showed lowest stress levels at the internal angles. Stress levels were higher at internal angles for "W" and "WoMOD". No difference was observed between the other groups when compared to "Wo" and "W" with "MOD" extension. Within the limits of this in vitro study, it was concluded that the presence of a proximal wall was an important biomechanical factor for the remaining dental tissue and that the cusps coverage did not show any advantages for the stress distribution when compared to the more conservative cavity preparations. / O objetivo deste trabalho foi analisar pelo método de elementos finitos (MEF) a distribuição de tensões em diferentes preparos cavitários que utilizaram a câmara pulpar disponível de um dente molar desvitalizado para a estabilidade e retenção de restauração “Endocrown”, submetida à simulação de forças oclusais funcionais. A tomografia computadorizada de uma mandíbula foi digitalmente reconstruída resultando num modelo 3D. Deste modelo foi extraída apenas a parte correspondente ao dente 37. Neste dente digital 3D, diferentes preparos cavitários sem e com envolvimento das cúspides foram modelados e editados, bem como uma restauração e camada de cimento. Todos os modelos com envolvimento das cúspides tiveram uma extensão mesio-ocluso-distal (MOD). Para a obtenção do coeficiente de Poisson e módulo de elasticidade do material restaurador utilizados no MEF, uma cerâmica foi submetida a teste de resistência à flexão. Foram obtidos os seguintes grupos: DH, dente hígido (controle); dois grupos sem envolvimento das cúspides, SeOD (extensão ocluso-distal) e SeMOD (extensão mésio-ocluso-distal); três grupos com envolvimento das cúspides, CeV (envolvimento das cúspides vestibulares), CeL (envolvimento das cúspides linguais) e CeT (envolvimento de todas as cúspides); e RM, remanescente de 2 mm acima do limite esmalte–cimento (LEC). Todos os grupos foram submetidos à simulação de uma carga de 200 N, no software Ansys Workbench v12, avaliando a distribuição de tensões principais de Rankine geradas nos preparos. As simulações demonstraram que os melhores resultados foram obtidos no grupo SeOD. Os resultados dos outros grupos apresentaram leve diferença, sendo muito próximos os resultados obtidos entre preparos cavitários sem e com envolvimento de cúspides, de extensão MOD. Com base nos resultados obtidos, pôde-se concluir que a presença de uma parede proximal é importante fator para beneficiar a biomecânica do remanescente dental, e que o envolvimento cuspídeo não forneceu um melhor prognóstico da situação quando comparando a preparos cavitários mais conservadores.

<p>Uvod. Usled kompromitovanja strukturnog integriteta, rekonstruktivne procedure na endodontski lečenim zubima moraju se veoma pažljivo isplanirati, pogotovo u specifičnoj grupi zuba kao &scaron;to su premolari. U stomatolo&scaron;koj naučnoj i stručnoj javnosti ne postoji usagla&scaron;en stav o tome koja endodontska instrumentacija i rekonstruktivna procedura primenjena u slučajevima ekstenzivnog gubitka zubne supstance predstavlja metodu izbora sa biomehaničkog aspekta. U okviru prezentovane doktorske disertacije ispitivan je uticaj varijacija u endodontskoj instrumentaciji i restaurativnim procedurama na promene naponskih stanja u zubnim tkivima i rekonstruktivnim materijalima kod premolara sa ekstenzivnim gubitkom zubne strukture. Metode. Osnovni 3D model je kreiran pomoću CT snimaka zdravog drugog gornjeg premolara u SolidWorks programu za modelovanje. Kreirano je 135 različitih modela, u kojima su metodom konačnih elemenata proračunati fon Mizesovi naponi u položaju maksimalne interkuspidacije pod dejstvom sile od 150 N. Statistička analiza je izvr&scaron;ena koristeći Op&scaron;ti linearni model. Rezultati. Indirektne zubne rekonstrukcije imaju povoljniji uticaj na naponska stanja u zubnim tkivima. Ukoliko se koristi direktna restauracija, povoljniji su naponi u dentinu i gleđi ukoliko se redukuje palatinalna kvržca. Upotreba kočića uz ispun snižava napone u zubnim tkivima samo u slučaju MOD kaviteta. Naponi u dentinu su niži pri apikalnom terminusu 0,5 mm i instrumentaciji instrumentima manje veličine (kod modela sa kočićem i indirektnim nadoknadama). Uglavnom procedure koje su povoljne za napone u dentinu, nepovoljne su za napone u zubnoj nadoknadi i obratno. Zaključci. Kod opsežnih MOD kaviteta a samo ukoliko se ne redukuje visina palatinalne kvržice, preporučuje se upotreba kompozitnog kočića. Smanjenje povr&scaron;ine zubnih tkiva u kojima su naponi visoki (iako su najvi&scaron;e vrednosti napona slične), moglo bi da utiče na dugotrajnost endodontski lečenih i rekonstruisanih zuba. Krući rekonstruktivni materijali povoljnije utiču na napone u zubnim tkivima biomehanički kompromitovanih endodontski lečenih zuba. Čini se da je optimalnije, u rekonstruktivnim re&scaron;enjima koja podrazumevaju upotrebu kočića, postaviti apikalni terminus bliže vrhu korena i koristiti instrumente srednje &scaron;irine.</p> / <p>Background. Restoration of an endodontically treated premolar with a wide and deep mesial-occlusal-distal (MOD) cavity is often complex due to biomechanical weakening of the tooth. There are no definitive recommendations on the optimal restoration in these cases. The aim of this study was to determine the effects of different endodontic and restorative procedures on von Mises stress values and distribution in dental tissues and restorative materials using finite element analysis (FEA). Methods. Based on CT scans of an second upper premolar, extracted for orthodontic reasons, 135 3D endodontically treated tooth models were created. Each model was subjected to a summary force of 150 N on the occlusal surface simulating the normal biting pattern and maximal von Mises stresses were calculated. Results. MODP cavity design seems to reduce von Mises stress values in dental tissues and P seems to transfer some of the stresses from dental tissues to the composite filling in the MOD cavity when direct restorations are used. Indirect restorations caused lower stresses within dentin. Apical terminus of 0.5 mm induces lower, while the terminus of 1.5 mm induces the highest stresses in dentin in models restored with direct composite and post. It seems that from the aspect of the tooth tissue, it is more recommended to use smaller endodontic instruments sizes. Conclusions. Stiffer restorative materials cause lower stresses in dentin of an endodontically treated structurally weakened tooth, and if a direct restoration is to be used, palatal cuspal reduction could be beneficial for the longevity of the tooth and the restoration. Further, in a wide and deep MOD cavity, without cuspal reduction, the use of a FRC post is recommended in order to reduce the stresses in the enamel and dentin. Moreover, it seems that it is beneficial for the stresses in the tooth tissue to place the apical terminus closer to the root apex as well as to use smaller size endodontic instruments.</p>

<p>Gubitak tvrdih zubnih struktura usled karijesne lezije, traume ili ekstenzivne preparacije dovodi do smanjenja otpornosti preostalih zubnih struktura na dejstvo sila prilikom žvakanja. Osnovni zadatak restaurativne procedure je da se ponovo uspostavi anatomo-morfolo&scaron;ka funkcija zuba i da se preostale zdrave zubne strukture za&scaron;tite od nepovoljnog odgovora na dejstvo sila. Cilj doktorske disertacije bio je da se ispita uticaj različitih restaurativnih procedura na biomehaničke karakteristike premolara sa ekstenzivnim kavitetima. Materijal i metode: Trodimenzionalni model intaktnog drugog gornjeg premolara kreiran je u SolidWorks računarskom programu, na osnovu snimaka ekstrahovanog zuba primenom vi&scaron;eslojnog spiralnog kompjuterizovanog tomografa. Na osnovu ovog modela potom je kreirano ukupno 48 modela, koji su podeljeni u dve grupe: modeli vitalnog premolara sa MOD kavitetom (I grupa) i modeli premolara sa endodontski lečenim kanalom korena sa MOD kavitetom (II grupa). U svakoj grupi ispitivan je uticaj 4 vrste restaurativnog materijala (direktan kompozitni ispun, direktan kompozitni ispun sa smolom modifikovanim glas-jonomer cementom u vidu podloge, indirektan kompozitni ispun, keramički ispun), 3 dizajna preparacije kaviteta (bez skraćivanja kvržica, sa skraćivanjem palatinalne kvržice 2mm, sa skraćivanjem palatinalne i bukalne kvržice 2mm) i 2 &scaron;irine istmusa (1/2 i 2/3 interkuspalnog razmaka). Primenom metode konačnih elemenata proračunate su vrednosti von Mises napona u zubnim strukturama i ispunu za sve modele pri dejstvu statičke sile od 200N. Rezultati: Dizajn preparacije kaviteta je pokazao najveći uticaj na vrednosti von Mises napona u zubnim strukturama. Pri tome, postupak skraćivanja palatinalne, kao i obe kvržice, doprineo je smanjenju vrednosti von Mises napona u gleđi na modelima obe grupe; dok je postupak skraćivanja bukalne i palatinalne kvržice doprineo smanjenju vrednosti von Mises napona u dentinu na modelima vitalnog premolara. U obe grupe, vrsta restaurativnog materijala pokazala je uticaj na vrednosti von Mises napona u gleđi, pri čemu je keramički ispun doveo do pojave napona značajno manjih vrednosti u odnosu na direktan i indirektan kompozitni ispun.Vrsta restaurativnog materijala je uticala i na vrednosti von Mises napona u dentinu, ali samo na modelima vitalnog premolara; pri tome su indirektni kompozitni i keramički ispun podjednako doprineli pojavi napona manjih vrednosti. &Scaron;irina istmusa je uticala na vrednosti von Mises napona u gleđi i dentinu na modelima vitalnog premolara. &Scaron;irina istmusa 1/2 interkuspalnog razmaka dovela je do pojave napona manjih vrednosti u gleđi, dok je &scaron;irina istmusa 2/3 interkuspalnog razmaka dovela do pojave napona manjih vrednosti u dentinu.</p> / <p>Loss of tooth structure from caries, trauma or extensive preparation decreases fracture resistance of tooth. The main goal of restorative procedure is to rebuild lost structures and to protect remaining tooth structures from unfavorable responses from masticatory forces. Aim of thesis was to investigate the influence of different restorative procedures on biomechanical properties of premolar with extensive cavities. Materials and Methods: Three dimensional model of intact maxillary second premolar, based on computerized tomography scan images of extracted tooth, was designed using SolidWorks software. Using this model, 48 models were designed and divided in two groups: models of vital premolars with MOD cavities (group I), and models of premolars with root canal treatment with MOD cavities (group II). In each group use of four restorative materials (direct composite resin restoration, direct composite resin restoration with resin modified glass-ionomer cement as base, indirect composite resin restoration, ceramic restoration), three cavity preparation designs (without cusp coverage, 2mm palatal cusp coverage, 2mm palatal and buccal cusp coverage) and two isthmus width (1/2 and 2/3 intercuspal width) were simulated. After applying static load of 200N, von Mises stresses in enamel, dentin and restoration were calculated using finite element analysis. Results: Cavity preparation design showed the most significant influence on von Mises stress values in tooth structures. Cusp coverage in general decreased stress values in enamel, while palatal and buccal cusp coverage decreased stress values in dentin only in group I. Restorative material affected stress values in enamel, were ceramic restoration contributed to minimal stress values. In dentin, indirect composite resin and ceramic restoration showed no difference in reducing von Mises stress values, but only for models in group I. Cavity isthmus width had influence on stress values in tooth structures only in group I. 1/2 isthmus width decreased stress values in enamel, while 2/3 isthmus width showed same effect in dentin. Conclusion: In order to provide optimal biomechanical characteristics of tooth structures, premolars with MOD cavity should be restored with ceramic overlay covering both palatal and buccal cusp.</p>

Este estudo se propõe a analisar a resposta pulpar de dentes humanos a preparos cavitários de classe V, em função de duas diferentes técnicas de instrumentação e de duas diferentes técnicas de restauração. Para tal, cavidades classe V, nas superfícies vestibulares de 48 pré-molares hígidos de pacientes entre 11 e 25 anos, que estavam em tratamento ortodôntico, foram preparadas e restauradas de acordo com os seguintes grupos experimentais: G 1 (n=24) - preparos cavitários realizados com ponta diamantada em alta rotação, restaurados com guta-percha plastificada, cimento ionômero de vidro e verniz cavitário (G 1A; n=12) ou com técnicas adesivas (sistema restaurador adesivo aplicando-se o condicionamento ácido total) e cimento ionômero de vidro (G 1B; n=12); G 2 (n=24) - preparos cavitários com ponta CVD ativada por ultrassom, restaurados com gutapercha plastificada, cimento ionômero de vidro e verniz cavitário (G 2A; n=12) ou com técnicas adesivas (sistema restaurador adesivo aplicando-se o condicionamento ácido total) e cimento ionômero de vidro (G 2B; n=12); e G 3 (controle; n=4) - dentes que foram extraídos sem a realização de qualquer procedimento. Os preparos cavitários foram realizados mantendo o assoalho da cavidade o mais próximo possível da polpa, no entanto, sem provocar exposição pulpar. Os dentes foram extraídos após três períodos experimentais (imediato, sete e trinta dias após o preparo cavitário), fixados, descalcificados, e processados histologicamente. Cortes teciduais longitudinais seriados de 5 m foram obtidos, corados pelas técnicas de H & E e de Brown & Brenn, e examinados em microscopia ótica. As avaliações morfométricas e por escores foram realizadas e os resultados das mesmas, submetidos, respectivamente, aos testes estatísticos de Mann-Whitney e de Kruskal-Wallis/Dunn, adotando-se um nível de significância de 5%. No período inicial, todos os grupos experimentais (1A, 1B, 2A e 2B) exibiram ligeiro desarranjo da camada odontoblástica vacuolizada e leve invasão da zona acelular de Weil. Não houve diferença entre os grupos experimentais iniciais e o grupo controle. No intervalo de sete dias, pôde-se observar redução da camada odontoblástica, muitos núcleos de odontoblastos aspirados nos túbulos dentinários, alguns espécimes com ausência de pré-dentina e resposta inflamatória aguda com hemorragia. Trinta dias depois, cinco espécimes do total avaliado apresentaram dentina terciária; dois espécimes do grupo 1B apresentaram necrose relacionada com a presença de bactérias nos túbulos dentinários; e os demais mostraram graus variados de inflamação crônica, associados a restaurações adesivas ou a processos de reparo, com proliferação de vasos e persistência de focos de hemorragia. Portanto, os dois tipos de instrumentação cavitária promovem respostas pulpares similares entre si, mas as diferentes técnicas restauradoras promovem efeitos significativamente diferentes sobre o complexo dentinopulpar. / The aim of this study is to analyze the pulp response of human teeth to class V cavity preparation, in function of two different instrumentation and restorative techniques. Class V cavities were made on the buccal surfaces of 48 sound human pre-molars from orthodontic patients from 11 to 25 years, and were divided as follows: G1 (n=24) cavity preparations were made with diamond bur under high speed, restored with either plasticized gutta-percha, glass ionomer cement and surface coated with varnish (G1A) or adhesive protocol (total etch technique and adhesive system application) with glass ionomer filling (G1B); G2 (n=24) cavity preparations were made with diamond CVD point and ultrasonic device, restored with either plasticized gutta-percha, glass ionomer cement and surface coated with varnish (G2A) or adhesive protocol (total etch technique and adhesive system application) with glass ionomer filling (G2B); and control group G3 (n=4) extracted teeth with no previous cavity preparation. All avities were prepared with the cavity floor as close to the pulp as possible, without causing pulp exposure. Teeth extractions were made in three experimental periods (immediate, 7 and 30 days after cavity preparation) and right after extraction they were submitted to histological procedures. Longitudinal tissue serial sections of 5 mm were obtained, H&E and Brown&Brenn stained, and analyzed under optical microscope. Morphometric and score evaluations were carried out and data from both were, respectively, submitted to Mann-Whitney and Kruskal-Wallis/Dunn tests, with 5% significance. Immediately, all experimental groups (1A, 1B, 2A and 2B) exhibited a discrete disorganization of the odontoblastic layer and invasion of the Weil zone. There was no difference between experimental and control groups. At 7-day interval, a decrease of the odontoblastic layer was observed. Many odontoblasts nucleus were seen displaced into the dentinal tubules. Some specimens showed absence of pre-dentine and inflammatory pulp response with hemorrhage. Thirty days later, five specimens presented tertiary dentin formation; two specimens from group 1B presented necrosis coincident with bacteria inside the dentinal tubules; the other specimens showed various degrees of chronic inflammation, associated to adhesive restorations or repair processes, with blood vessels proliferation and persistent hemorrhagic areas. Therefore, both instrumentation techniques promoted similar pulp response, but different restoration procedures elicited significantly different responses of the dentinpulp complex.

Indiana University-Purdue University Indianapolis (IUPUI) / This in-vitro, prospective, randomized study microscopically compared the debridement efficacy of passive ultrasonic irrigation (PUI) using the Ultrasonic Bypass System and different irrigating protocols. Eighty extracted maxillary anterior teeth were randomly assigned to four groups. Teeth were instrumented using EndoSequence rotary instrument system and treated with passive ultrasonic irrigation with different irrigating regimens for one minute. Group one (control) was treated with hand/rotary instrumentation. Group two was treated with hand/rotary instrumentation followed by a one-minute PUI using the Ultrasonic Bypass System with 6.0-percent NaOCl. Group three was treated with hand/rotary instrumentation followed by a one-minute PUI using the Ultrasonic Bypass System with 17-percent EDTA. Group four was treated with hand/rotary instrumentation followed by a one-minute PUI using the Ultrasonic Bypass System with 30 seconds of 6.0-percent NaOCl and 30 seconds of 17-percent EDTA. Teeth were sectioned longitudinally and each half was divided into three equal parts from the anatomic apex. The half with the most visible part of the apex was used for SEM evaluation. A scoring system for debris and smear layer removal was used. Statistical analysis was performed using a Kruskal-Wallis test, which determines if there are any differences among the four groups. Following this test, a Wilcoxon Rank Sum test was used to compare each pair of groups. The addition of a one-minute PUI with the Ultrasonic Bypass System significantly enhanced the removal of smear layer when compared with the hand/rotary instrumentation with conventional irrigating solutions. The Ultrasonic Bypass System when used with the combination of 6.0-percent NaOCl and 17-percent EDTA after hand/rotary instrumentation significantly removed smear layer at the coronal, middle, and apical areas of a tooth when compared with all other groups. A one-minute PUI with the Ultrasonic Bypass System combined with NaOCl and EDTA is significantly better in smear removal and ultimately will result cleaner canal wall.