O objetivo do trabalho foi avaliar as alterações morfológicas bi, tridimensionais, e o transporte em canais mesiais de molares inferiores com curvatura acentuada. Selecionou-se molares inferiores com dois canais e forames independentes, livres de nódulos pulpares, reabsorção interna, tratamento endodôntico prévio, fratura radicular e dentro do padrão de raio e ângulo de curvatura, avaliados pelos exames radiográficos, tomográficos cone bean e microtomográficos. Partiu-se de 393 dentes para selecionar 15 dentro deste padrão morfológico. Esses dentes foram submetidos à microtomografia antes da instrumentação, após o preparo com instrumento Reciproc® R25 e após o preparo por cada lima dos sistemas de complementação (Mtwo e K3). Os dados morfométricos foram analisados pelo programa CTAn e as análises estatísticas foram realizadas utilizando o programa SPSS onde observou-se os seguintes resultados: a análise morfométrica bidimensional mostrou que a área e o perímetro apresentaram aumento gradual a cada milímetro avaliado, partindo do primeiro milímetro apical; houve também aumento gradual de área e de perímetro a cada troca de instrumento de acordo com o que se realizou o preparo biomecânico dentro dos conjuntos de grupos; houve diferença estatisticamente significante de área e de perímetro dos canais radiculares apenas após o preparo com os instrumentos #40 taper 04 e taper 02 (P<0,05). Em relação à distância do ápice, houve diferença estatística de área entre todos os milímetros avaliados (P<0,05). Em relação ao perímetro, não houve diferença entre os milímetros 1 e 2; e, 4 e 5 (P>0,05), entretanto com diferença entre o terceiro milímetro e os demais (P<0,05). As análises morfológicas tridimensionais de volume, área de superfície e SMI (Índice de Modelo Estrutural) do canal radicular, tiveram comportamento semelhante entre os grupos. Os espécimes submetidos à complementação, com instrumentos taper 04 e taper 02, não apresentaram diferença estatística após os preparos (P>0,05), com diferença entre os canais preparados com a R25 e os canais originais (P<0,05). Quando comparados os conjuntos de grupos, nenhum grupo análogo apresentou diferença estatística (P>0,05). Foi analisado o transporte por terços (cervical, médio e apical) e por todo o canal, não sendo detectada diferença estatisticamente significante (P>0,05) entre os terços, nem do canal todo entre a complementação pelos instrumentos taper 04 (Mtwo) e taper 02 (K3). / The purpose of this study was to evaluate the two- and three-dimensional morphological changes, and the transportation that occurs in the mesial canals of mandibular molars with severe curvature. Molars were selected with two independent canals and foramina, no pulpal nodules, internal resorptions, previous endodontic treatment or root fracture and within the standard radius and angle of curvature evaluated by radiographs, cone-beam tomography and microtomography. From the 393 teeth initially selected, 15 fulfilled the selected parameters. The teeth were subjected to microtomography before instrumentation, after instrumentation with Reciproc® R25 and after preparation with each file of the complementary systems (MTwo and K3). The morphometric data were analyzed by CTAn software and the statistical analysis was performed using the SPSS software where the following results were observed. The two-dimensional morphometric analysis showed that the area and the perimeter presented a gradual increase for every evaluated millimeter, starting from the first apical millimeter. There was also a gradual increase in area and perimeter with each change of instrument according to the biomechanical within the sets of groups. There was a statistically significant difference in area and perimeter of root canals after the preparation with the instruments #40 taper 04 and taper 02 (P <0.05). Regarding the distance from the apex area, there was statistically difference among all evaluated millimeters (P <0.05). Regarding the perimeter, there was no difference between 1 and 2 mm, and 4 or 5 (P> 0.05), however with a difference between the third millimeter and the others (P <0.05). The three-dimensional morphological analyses of volume, surface area and root canal SMI (Structural Model Index) of the root canal showed a similar behavior among the groups. The specimens subjected to complementation to the instrumentation with instruments of tapers 04 and 02 showed no statistically significant difference after preparation (P> 0.05), with significant difference between the original and prepared canals (P <0.05). When comparing the sets of groups, no analogue group presented a statistically significant difference (P> 0.05). Transport was analyzed by thirds (cervical, middle and apical) and throughout the canal there, without statistically difference (P> 0.05) among the thirds or between groups with complementation with taper 04 (MTwo) and taper 02 (K3) instruments.

O objetivo do trabalho foi avaliar as alterações morfológicas bi, tridimensionais, e o transporte em canais mesiais de molares inferiores com curvatura acentuada. Selecionou-se molares inferiores com dois canais e forames independentes, livres de nódulos pulpares, reabsorção interna, tratamento endodôntico prévio, fratura radicular e dentro do padrão de raio e ângulo de curvatura, avaliados pelos exames radiográficos, tomográficos cone bean e microtomográficos. Partiu-se de 393 dentes para selecionar 15 dentro deste padrão morfológico. Esses dentes foram submetidos à microtomografia antes da instrumentação, após o preparo com instrumento Reciproc® R25 e após o preparo por cada lima dos sistemas de complementação (Mtwo e K3). Os dados morfométricos foram analisados pelo programa CTAn e as análises estatísticas foram realizadas utilizando o programa SPSS onde observou-se os seguintes resultados: a análise morfométrica bidimensional mostrou que a área e o perímetro apresentaram aumento gradual a cada milímetro avaliado, partindo do primeiro milímetro apical; houve também aumento gradual de área e de perímetro a cada troca de instrumento de acordo com o que se realizou o preparo biomecânico dentro dos conjuntos de grupos; houve diferença estatisticamente significante de área e de perímetro dos canais radiculares apenas após o preparo com os instrumentos #40 taper 04 e taper 02 (P<0,05). Em relação à distância do ápice, houve diferença estatística de área entre todos os milímetros avaliados (P<0,05). Em relação ao perímetro, não houve diferença entre os milímetros 1 e 2; e, 4 e 5 (P>0,05), entretanto com diferença entre o terceiro milímetro e os demais (P<0,05). As análises morfológicas tridimensionais de volume, área de superfície e SMI (Índice de Modelo Estrutural) do canal radicular, tiveram comportamento semelhante entre os grupos. Os espécimes submetidos à complementação, com instrumentos taper 04 e taper 02, não apresentaram diferença estatística após os preparos (P>0,05), com diferença entre os canais preparados com a R25 e os canais originais (P<0,05). Quando comparados os conjuntos de grupos, nenhum grupo análogo apresentou diferença estatística (P>0,05). Foi analisado o transporte por terços (cervical, médio e apical) e por todo o canal, não sendo detectada diferença estatisticamente significante (P>0,05) entre os terços, nem do canal todo entre a complementação pelos instrumentos taper 04 (Mtwo) e taper 02 (K3). / The purpose of this study was to evaluate the two- and three-dimensional morphological changes, and the transportation that occurs in the mesial canals of mandibular molars with severe curvature. Molars were selected with two independent canals and foramina, no pulpal nodules, internal resorptions, previous endodontic treatment or root fracture and within the standard radius and angle of curvature evaluated by radiographs, cone-beam tomography and microtomography. From the 393 teeth initially selected, 15 fulfilled the selected parameters. The teeth were subjected to microtomography before instrumentation, after instrumentation with Reciproc® R25 and after preparation with each file of the complementary systems (MTwo and K3). The morphometric data were analyzed by CTAn software and the statistical analysis was performed using the SPSS software where the following results were observed. The two-dimensional morphometric analysis showed that the area and the perimeter presented a gradual increase for every evaluated millimeter, starting from the first apical millimeter. There was also a gradual increase in area and perimeter with each change of instrument according to the biomechanical within the sets of groups. There was a statistically significant difference in area and perimeter of root canals after the preparation with the instruments #40 taper 04 and taper 02 (P <0.05). Regarding the distance from the apex area, there was statistically difference among all evaluated millimeters (P <0.05). Regarding the perimeter, there was no difference between 1 and 2 mm, and 4 or 5 (P> 0.05), however with a difference between the third millimeter and the others (P <0.05). The three-dimensional morphological analyses of volume, surface area and root canal SMI (Structural Model Index) of the root canal showed a similar behavior among the groups. The specimens subjected to complementation to the instrumentation with instruments of tapers 04 and 02 showed no statistically significant difference after preparation (P> 0.05), with significant difference between the original and prepared canals (P <0.05). When comparing the sets of groups, no analogue group presented a statistically significant difference (P> 0.05). Transport was analyzed by thirds (cervical, middle and apical) and throughout the canal there, without statistically difference (P> 0.05) among the thirds or between groups with complementation with taper 04 (MTwo) and taper 02 (K3) instruments.

Magister Scientiae Dentium - MSc(Dent) / NiTi rotary instruments have shape memory and are highly flexible and super-elastic. These properties of the metal alloy allows for ease of root canal preparation to ultimately result in a root canal preparation that has a continuous taper, while canal shape and curvature is maintained. It must be noted that the NiTi rotary instrumentation may have an effect on root canal dentine, which may manifest as dentine damage. Different NiTi rotary systems on the market vary with regards to their design features and kinematics, which may influence dentine damage. The purpose of this in-vitro study was to compare the effect of four different NiTi rotary systems, as well as stainless steel files on root canal dentine. One hundred and eighty permanent human mandibular molar mesial roots were used for the study. The total samples were randomly divided into six groups, where one group (n=30) was left unprepared to serve as the control group. The remaining five groups were randomly assigned to a nickel-titanium rotary instrumentation system and one stainless steel hand file group. Group 1: Control group; Group 2: Stainless steel files group; Group 3: Wave One (Dentsply Maillefer) rotary group; Group 4: ProTaper NEXT (Dentsply Maillefer) rotary group; Group 5: iRaCe (FKG Dentaire) rotary group; Group 6: BT-Race (FKG Dentaire) rotary group.The root canal preparations were carried out according to the manufacturers' recommendations, after decoronation of the tooth crowns. Sodium hypochlorite (5,25%) and 17% EDTA was used as a root canal irrigant and a chelating agent during canal preparation. Each root segment was sectioned at 3mm, 6mm and 9mm from the apex. The root segments were observed under a stereomicroscope at 12x magnification and digital camera at 40 x magnification for the appearance of dentine damage. The images were observed by the author and an impartial second observer. Root segments were observed for the appearance of dentine damage (microcracks, craze lines or fractures), and samples were described as having 'dentine defect' or 'no dentine defect'. Data for the different groups were collected and results were calculated and the total incidence of dentine damage was as follows: Control group = 0% Stainless steel hand files group = 0% Wave One group = 56, 67% ProTaper NEXT group = 60% iRaCe group = 60% BT-Race group = 56, 67% There are no significant differences between the groups: WaveOne, ProTaper NEXT, iRACE and BT-Race. However, there is a significant difference between the four groups and the stainless steel group (p<0.0001).

Indiana University-Purdue University Indianapolis (IUPUI) / Introduction: Profound pulpal anesthesia is not always adequate in mandibular teeth after the administration of local anesthesia, especially in the presence of irreversible pulpitis. Failure to achieve anesthesia has been seen in 30–80% of patients in teeth with a diagnosis of irreversible pulpitis. Onpharma™ developed an FDA-approved device that uses sodium bicarbonate to buffer a standard local anesthetic (LA) solution so that its pH may become closer to its pKa. Claims have been made that buffering a local anesthetic increases the anesthetic’s effect. Previous studies on the anesthetic efficacy of Onpharma’s Onset buffering system were inconclusive and may be dependent on the techniques used. Objectives: The aim of this study is to determine whether a buffered local anesthetic can lead to more profound and faster pulpal anesthesia in mandibular molars diagnosed with symptomatic irreversible pulpitis as compared to a standard, unbuffered local anesthetic. Materials and Methods: 40 total subjects completed the study. Screened and eligible subjects with a mandibular molar diagnosed with symptomatic irreversible pulpitis were randomly allocated into 2 groups so 1 group received a total of 3 cartridges of a standard, unbuffered 2% lidocaine with 1:100,000 epinephrine via inferior alveolar nerve block (IANB) followed by supplemental buccal and lingual infiltrations, while the other received the equivalent yet buffered formulation. An electronic pulp tester (EPT) was used to objectively determine baseline pulpal status of the affected tooth, followed by 2-minute interval testing following the administration of all local anesthesia. The onset of pulpal anesthesia was defined by the first of 2 consecutive EPT=80 readings, and the endodontic treatment could begin. Profound pulpal anesthesia was ultimately determined if the patient reported a comfortable pulpotomy as reflected on the Wong-Baker FACES Visual Analog Scale. Null Hypothesis 1: Subjects possessing mandibular molars diagnosed with symptomatic irreversible pulpitis will not achieve pulpal anesthesia more profoundly using buffered 2% lidocaine w/ 1:100,000 epinephrine in comparison to the standard, unbuffered anesthetic formulation. Null hypothesis 2: Subjects possessing mandibular molars diagnosed with symptomatic irreversible pulpitis will not achieve pulpal anesthesia faster using buffered 2% lidocaine w/ 1:100,000 epinephrine in comparison to the standard, unbuffered anesthetic formulation. Results: We observed a local anesthetic success rate of 45% in the buffered group, 70% in the unbuffered group, and ultimately 57.5% between both groups. The findings further indicate that the VAS scores after pulpotomy is significantly different between the 2 groups (p=0.019), with the unbuffered group having a more profound mean VAS score of 1.2 (as opposed to a buffered mean of 3.1). Regarding the time of onset for pulpal anesthesia, there was no statistically significant difference noted between the buffered and unbuffered groups. Conclusion: Based on the findings of this study, the null hypothesis 1 cannot be rejected since unbuffered 2% lidocaine with 1:100,000 epinephrine had a statistically significant increase in profound pulpal anesthesia compared to the buffered equivalent. The null hypothesis 2 cannot be rejected since there was no evidence of a significant difference in the time to pulpal anesthesia between the buffered and unbuffered groups.