Shaping ability of hand, rotary and reciprocating files in primary teeth: a micro-CT study in vitro.

PURPOSE: Compare canal transportation and dentin removal using micro computed tomography (micro-CT) and measure instrumentation time in the root canal preparation of primary molars using K-files, ProDesign Logic and Reciproc files. METHODS: A representative sample of 81 root canals of primary molars was randomised into three groups: K-files (#15-40), ProDesign Logic (#25) and Reciproc (R25). A single-trained operator prepared all root canals. A standardised micro-CT evaluation was performed before and after instrumentation using the CTan® program. Instrumentation time was also recorded. Statistical analysis involved one-way ANOVA, Tukey's post hoc test, Kruskal-Wallis test and Dunn's test, considering a 5% level of significance. RESULTS: Reciproc led to more canal transportation than K-files and ProDesign Logic (p < 0.001) in middle third, whereas K-files led to the most canal transportation in the apical third (p = 0.017). ProDesign Logic and Reciproc removed less dentin on the opposite side of the root curvature in the apical third compared to K-files (p = 0.008). Instrumentation time was better with ProDesign Logic and Reciproc than K-files (p < 0.001). CONCLUSION: ProDesign Logic demonstrated good results with regard to canal transportation and required less instrumentation time in primary molars. Reciproc and K-files led to the most canal transportation in the middle and apical third, respectively.

Influence of minimally invasive endodontic access cavities on root canal shaping and filling ability, pulp chamber cleaning and fracture resistance of extracted human mandibular incisors.

AIM: To evaluate the influence of the location and design of endodontic access cavities on root canal shaping and filling ability, pulp chamber cleaning and fracture resistance of extracted human mandibular incisors. METHODOLOGY: After pre-selection using periapical radiographs, forty extracted intact human mandibular incisors were scanned in a micro-computed tomographic device. The teeth were matched based on similar anatomical features of the canals and assigned to four experimental groups (n = 10) according to the endodontic access cavity and root canal preparation protocol: traditional/TRUShape (T/TRU); traditional/MTwo (T/MT); minimally invasive/TRUShape (MI/TRU); and minimally invasive/MTwo (MI/MT). The samples were scanned after root canal instrumentation and filling procedures. The parameters evaluated were as follows: volume and area of the root canal, noninstrumented canal areas, canal transportation and centring ratio, accumulated hard tissue debris, voids in root canal fillings and remnants of root canal filling materials in the pulp chamber. After root canal filling and cavity restoration procedures, the samples were submitted to a fracture resistance test. Data were statistically analysed using Shapiro-Wilk, one-way anova and Bonferroni tests with a significance level of 5% (α = 0.05). RESULTS: There was no difference regarding all parameters evaluated before and after root canal preparation (volume and area of the root canal, noninstrumented canal areas, canal transportation and centring ratio, and accumulated hard tissue debris) amongst the groups (P > 0.05). MI/TRU and MI/MT groups were associated with significantly more voids in root canal fillings when compared to the T/TRU and T/MT groups (P < 0.05). Percentage of root canal filling material remnants in the pulp chamber after cleaning procedures and mean fracture resistance values were not significantly different amongst the four experimental groups (P > 0.05). CONCLUSIONS: The location and design of the endodontic access cavity did not impact on root canal preparation nor resistance to fracture of extracted mandibular incisors, regardless of the instrument used. Minimally invasive access cavities were associated with significantly more voids in root canal fillings.

Effects of several storage media on viability and proliferation capacity of periodontal ligament cells.

AIM: The purpose of this study was to investigate the effect of different storage media on viability and proliferation capacity of periodontal ligament cells. METHODS: Plates with periodontal ligament fibroblasts (PDLF) cells were incubated in skimmed and whole milk, recently prepared Hank's balanced salt solution (HBSS), Save-A-Tooth system's, coconut water, propylene glycol with 20% propolis, egg white, tap water (negative control) at 5 °C and 20 °C, for 24 h. In one of the plates of each temperature, cell viability was determined by MTT assay. In the remaining plates, the wells were filled and incubated with Minimum Essential Medium (MEM) at 37 °C for 24, 48, 72, 96, and 120 h. The proliferation capacity of PDFL cells was also evaluated by MTT assay. Data were statistically analyzed by Kruskal-Wallis, Scheffé and Mann-Whitney tests (α = 5%). RESULTS: At 5 °C, milk maintained more viable cells than other storage media immediately after exposure (0 h) and allowed greater proliferation capacity. At 20 °C, milk and HBSS had similar and allowed similar proliferation ability at 24 and 48 h. From 72 h onwards, capacity to maintain cell viability the proliferation rate of cells incubated in HBSS was superior than milk. At both temperature and experiments, Save-A-Tooth system was similar to tap water. CONCLUSION: Milk and HBSS were more effective in maintaining cellular viability and proliferation capacity than any other storage media. At 5 °C, the most viable alternative was milk. At 20 °C, HBSS had better results.

Effects of fatty acids and calf starter form on intake, growth, digestion, and selected blood metabolites in male calves from 0 to 4 months of age.

The objective of this research was to determine if form of calf starter (CS) and addition of a fatty acid blend (FA) influenced intake, growth, digestion, and indices of immune status and stress in calves from 0 to 4 mo of age. Male Holstein calves [n = 48; 41.9 kg of body weight (BW), standard error = 0.7; 2 to 3 d of age] were assigned to receive reconstituted whole milk powder [0.66 kg of dry matter (DM)/d to 39 d, then 0.33 kg of DM/d to weaning at 42 d] without or with added FA. Calf starters were textured (pellet, whole oats, whole corn) or pelleted and were offered for ad libitum consumption from 0 to 56 d, then blended with 5% chopped grass hay and fed from d 57 to 112. Starters contained 20% crude protein (CP) and 38 to 40% starch in the DM. From d 0 to 56, calves were housed individually. From d 57 to 112, calves were grouped into pens by treatment (n = 4/pen). Form of CS during the initial 56 d had no effect on intake or growth, though days with fluid feces (fecal score ≥2.5) were greater when calves were fed textured CS. Feeding FA during the initial 56-d increased average daily BW gain, gain-to-feed ratio, and change in hip width, and reduced the number of days calves were treated with antibiotics. During d 57 to 112, CS form had no effects on any performance measure. Adding FA to CS increased average daily BW gain and hip width change, and tended to improve efficiency of BW gain. Total-tract digestibility was estimated at 4, 6, and 8 wk with 5 calves per treatment, and at 10, 13, and 16 wk of age using pen (n = 3 per treatment) as the experimental unit. Feeding FA increased or tended to increase total-tract digestion of DM, organic matter, starch, neutral detergent fiber (NDF), acid detergent fiber (ADF), CP, and fat at one or more measurement periods. Calves fed a textured CS increased or tended to increase digestion of DM, organic matter, starch, sugar, NDF, ADF, and CP during wk 6 and 8. However, during the second 56-d phase, feeding textured CS reduced or tended to reduce digestion of DM, organic matter, starch, NDF, ADF, and fat during wk 13 and 16. Inclusion of FA in milk increased serum bactericidal activity before weaning. Serum haptoglobin concentration increased 3 d postweaning when calves were fed textured CS. Feeding FA improved animal health, digestion, and performance. Form of CS had few effects on animal performance.

Effects of the addition of nanoparticulate calcium carbonate on setting time, dimensional change, compressive strength, solubility and pH of MTA.

AIM: To evaluate nanoparticulate calcium carbonate (NPCC) using transmission electron microscopy and the effects of NPCC addition to MTA in regard to the setting time, dimensional change, compressive strength, solubility and pH. METHODOLOGY: The experimental groups were G1 (MTA), G2 (MTA with 5% NPCC) and G3 (MTA with 10% NPCC). The tests followed ISO and ADA standards. The specimens in the dimensional change and compressive strength tests were measured immediately after setting, after 24 h and after 30 days. In the solubility test, rings filled with cement were weighed after setting and after 30 days. The pH was measured after 24 h and 30 days. The data were analysed with the ANOVA, Tukey's and Kruskal-Wallis tests (α = 5%). RESULTS: The setting time was reduced (P < 0.05) in samples from G2 and G3 compared to G1. After 24 h, the dimensional change was similar amongst the groups, and after 30 days, G2 was associated with less alteration than G1 and G3. There was a difference in the compressive strength (P < 0.001) after 24 h and 30 days (G1 > G2 > G3). The solubility test revealed a difference amongst the groups when the specimens were hydrated: G2 > G1 > G3 and dehydrated: G3 > G2 > G1. The pH of the groups was similar at 24 h with higher values in each group after 30 days (P < 0.05), and G2 and G3 had similar mean pH values but both were higher than G1. CONCLUSIONS: Nanoparticulate calcium carbonate had a cubic morphology with few impurities. The addition of nanoparticulate calcium carbonate to MTA accelerated the setting time, decreased compressive strength and, after 30 days, resulted in lower dimensional change (G2), higher solubility and a higher pH.

Subcutaneous connective tissue reactions to iRoot SP, mineral trioxide aggregate (MTA) Fillapex, DiaRoot BioAggregate and MTA.

AIM: To evaluate connective tissue reactions to iRoot SP (Innovative Bioceramics, Vancouver, BC, Canada), mineral trioxide aggregate (MTA) Fillapex (FLPX) (Angelus Soluções Odontológicas, Londrina, Brazil), DiaRoot Bioaggregate (DiaDent Group International, Burnaby, BC, Canada) and white MTA (Angelus, Londrina, Brazil) in Wistar rats. METHODOLOGY: A total of 128 dentine tubes filled with the materials and 32 empty tubes (control) were implanted into 32 rats. After 7, 15, 30 and 90 days (n = 8 per period), the animals were euthanized, and the tissues were processed for histological evaluation using haematoxylin-eosin (H&E) and Von Kossa (VK) staining. Observations were made for cellular inflammatory components and the presence of multinucleated giant cells (MNGC), macrophages and tissue necrosis. Data were analysed by Fisher's exact and Kruskal­Wallis tests (P < 0.05). RESULTS: In all experimental periods, MTA FLPX and iRoot SP scored higher than the other groups for the variable macrophages (P < 0.05). After 30- and 90-day experimental periods, MTA FLPX scored higher than the other groups for the variable MNGC (P < 0.05). After 90 days, the only group that exhibited samples with severe inflammatory response was MTA FLPX. VK positivity was observed in areas of necrosis in all groups, except in the control group. CONCLUSIONS: The materials were considered biologically acceptable except MTA FLPX, which remained toxic to subcutaneous tissue even after 90 days.

Influence of the exposure of MTA with and without calcium chloride to phosphate-buffered saline on the push-out bond strength to dentine.

AIM: To analyse the influence of exposure of mineral trioxide aggregate (MTA) with and without calcium chloride (CaCl2 ) to phosphate-buffered saline (PBS) on the push-out bond strength, over different experimental periods. METHODOLOGY: One hundred and twenty dentine discs with standardized cavities were filled with MTA with and without 10% CaCl2 . The specimens were randomly divided as follows (n = 30): (G1) MTA in contact with a moistened cotton pellet, (G2) MTA immersed in PBS, (G3) MTA + CaCl2 in contact with a moistened cotton pellet and (G4) MTA + CaCl2 immersed in PBS. The samples were stored for 3, 28 and 60 days. The bond strengths were measured with the Instron Testing machine. Data were analysed using the three-way anova and Tukey test (P < 0.05). RESULTS: In general, the samples of MTA with and without CaCl2 , exposed to PBS, had higher bond strength values in all study periods (P < 0.05). Analysis of the influence of addition of CaCl2 to MTA (G1 × G3) evidenced significant differences in bond strength in the different periods (P < 0.05). CONCLUSIONS: The exposure of MTA to PBS positively influenced the push-out bond strength, whereas the addition of CaCl2 had a negative influence.

Endodontic re-instrumentation enhances hydroxyl ion diffusion through radicular dentine.

AIM: To evaluate the diffusion of hydroxyl ions from calcium hydroxide paste (CH) before root canal filling and after retreatment. METHODOLOGY: After preparation of 60 root canals, the cementum layer was removed, and the canals and root surfaces were treated for smear layer removal. The apical third of roots was covered with adhesive. The canals were filled with CH, and the teeth were placed in individual vials containing 10 mL of distilled water, which had its pH measured after 7, 14, 21 and 28 days (pH1). The root canals were then divided into five groups and filled with Resilon/Real Seal (G1) or gutta-percha and Endofill (G2), Sealapex (G3), AH Plus (G4) or MTA Fillapex (G5) sealers. After storage for 7 days, the root canals were retreated. The CH was again inserted into the canals, and the teeth were placed in new vials containing 10 mL of distilled water. The pH was again measured at 7, 14, 21 and 28 days (pH2). The initial and final pH readings (pH1 and pH2) were compared by anova, anova2 and Tukey's tests (P < 0.05). RESULTS: The pH1 and pH2 measurements increased with time. The measurements obtained after retreatment were significantly higher than those obtained before root canal filling. CONCLUSIONS: Hydroxyl ions are able to diffuse through dentinal tubules. Regardless of the filling material, it was possible to re-establish the permeability of dentine to ionic diffusion after retreatment. Time had a positive influence on ionic diffusion.

Qualidade do leite de propriedades familiares praticantes de integração lavoura-pecuária em função do uso do solo / Milk quality of family farms practicing crop-livestock integration depending on land use

O objetivo do estudo foi investigar o uso do solo em propriedades familiares (PF) manejadas sob integração lavoura-pecuária (ILP) em bacia hidrográfica e relacionar com a qualidade do leite. Para tal, 14 PF foram caracterizadas e agrupadas quanto ao uso do solo (Grupos 1, 2 e 3) e monitoradas quanto à qualidade do leite, durante os meses de maio de 2010 a fevereiro de 2011. Nas amostras de leite, avaliou-se o teor de gordura, proteína e sólidos não gordurosos. Observou-se que o uso do solo objetivando o cultivo de grãos em detrimento do pastejo animal influencia negativamente o teor de gordura e proteína, em média 6,3% e 5,4%, respectivamente, sobretudo no período de verão. Assim, o planejamento de uso do solo em PF manejadas sob ILP é fundamental, pois a competição entre as atividades reflete na qualidade do leite. As PF especializadas na atividade leiteira apresentam melhor qualidade do leite durante as estações do ano.

The aim of this study was to investigate the land use practiced on family farms (FF), managed under crop-livestock integration (CLP) in the watershed and to evaluate the quality of milk. 14 FFs were characterized and grouped regarding soil use (Group 1, 2 and 3) and the quality of milk was monitored during the months of May, 2010 to February 2011. In these milk samples, we evaluated the fat, protein and non-fat solids content. It can be observed that the use of soil in a crop-livestock integration system, when the grain cultivation is prioritized over the animal grazing, influences negatively the fat and protein content, on average 6.3% and 5.4%, respectively, especially during the summer. Thus, the planning of the use of soil in FF managed under CLP is essential, because the competition between the activities was reflected in the quality of milk. The FF specialized in dairy farming produces better quality milk in all annual seasons.

Fracture strength of bovine incisors after intra-radicular treatment with MTA in an experimental immature tooth model.

AIM: To evaluate, using an experimental immature tooth model, the fracture resistance of bovine incisors submitted to different reinforcement treatments with mineral trioxide aggregate (MTA). METHODOLOGY: An immature tooth model was created by sectioning the coronal and apical portions of 40 bovine incisors 8 mm above and 12 mm below the cementoenamel junction. The root canals were irrigated with 1.0% sodium hypochlorite. They were enlarged both coronally and apically using number 703 carbide burs (ISO: 500-104-168-007-021) and their internal diameter was standardized to 2.1 mm. The specimens were assigned to four groups (n = 10): GI-control (without filling); GII-apical MTA plug + filling with gutta-percha and endodontic sealer; GIII-filling with MTA; GIV-apical MTA plug + filling with MTA + metallic post (Reforpost I). A polyether impression material was used to simulate the periodontal ligament. The specimens were submitted to a compressive load at a crosshead speed of 0.5 mm min(-1) in a servo-hydraulic universal testing machine (MTS 810) applied at 45 degrees to the long axis of the tooth until failure. Data were submitted to statistical analysis by the Kruskal-Wallis test at 5% significance level. RESULTS: GIV presented the highest fracture resistance (32.7N) and differed significantly from the other groups (P < 0.05). No statistically difference was found between GII (16.6N) and GIII (23.4N) (P > 0.05). GIII had a significantly higher fracture resistance than GI (P < 0.05). CONCLUSIONS: The use of MTA + metallic post as an intra-radicular reinforcement treatment increased the resistance to fracture of weakened bovine teeth in an experimental immature tooth model.

Técnica para realizar perforaciones radiculares cervicales en dientes de perros empleada para trabajos de investigación / Technique to accomplish root cervical perforations in dog´s teeth employed for investigation projects

El propósito del presente trabajo es proporcionar a investigadores, especialistas y alumnos de postgrado una técnica estandarizada que facilite la realización de perforaciones radiculares en dientes de perros, limitando errores y estableciendo una técnica base para llevar a cabo estos defectos dentarios. En este tipo de estudios el objetivo principal es evaluar la respuesta de los tejidos periodontales radiculares que ocasionan los materiales odontológicos para el sellado de las perforaciones. Para su realización es importante considerar factores como el tamaño y nivel de la perforación, la irrigación abundante, el tiempo de exposición y si el sellado se realizó inmediatamente o pasado algún tiempo, si están contaminadas o no. Asimismo se pretende limitar variables como la edad de los animales, enfermedad periodontal y el nivel de desarrollo radicular con la finalidad de establecer un patrón y que los factores ya mencionados no condicionen los resultados o resulten en falsos positivos

The purpose of the present work is provide to investigating, specialists and alumnis a standardized methodology that facilitate the root perforations accomplishment in dogs´ teeth, limiting mistakes and establishing a technical base to carry out these dental defects. In this type of studies the principal objective is to evaluate response of the root tissue periodontal that cause the dental materials for the sealed of the perforations. For your accomplishment is important to consider factors as the size and level of the perforation, the abundant irrigation, the exposition time and if the sealed was accomplished immediately or past some time, if they are contaminated or not. Also it es intended to limit variable as the age of the animals, periodontal disease and the root development level in order to establish a standard and that the already mentioned factors do not condition the results or result in untruthful positive

Tratamiento de perforaciones radiculares en dientes de perros con dos marcas comerciales de agregado trióxido mineral (MTA) / Root perforations treatment in dog´s teeth with two agregate mineral trioxide (MTA)

El propósito de este trabajo fue evaluar la respuesta de los tejidos periodontales interradiculares de dientes de perros, perforados y sellados inmediatamente con ProRoot MTA y MTA-Angelus. Concluido el tratamiento de conductos radiculares, se realizaron en cada diente perforaciones en la raíz mesial, a nivel de la entrada del conducto radicular, en dirección de la furca. 90 días después los perros fueron sacrificados por perfusión y las muestras procesadas para estudio microscópico. Los resultados mostraron neoformación de tejido mineralizado, sellando totalmente la perforación en todos los casos y mínima inflamación de tipo crónico, consecuente del extravasamiento de material sellador. La prueba no paramétrica de Kruskal-Wallis demostró no existir diferencia estadísticamente significante entre ambos materiales. El ProRoot MTA y el MTA-Angelusson materiales con adecuadas propiedades biológicas y crean las condiciones ideales para que ocurra la reparación de los tejidos periodontales interradiculares en dientes de perros

The purpose of this work was to evaluate tbe response of the periodontal tissue of dogs' teeth which was perforated and sealed immediately witb ProRootMTA and MTA-Angelus. Concluded the treatment of root canals, they were carried out in each tooth perforations in the root mesial, at level of the entrance of the root canal, in direction of the furca. 90 days later the dogs were sacrificed by perfusionand processed for microscopic study. The results showed neoformation of tissue mineralized sealing the perforation totally in all the cases and mínimum inflammation of chronic type, consequent of the extravasation of sealer material. The non parametric test of Kruskal Wallis demonstrated not to exist differs statistically significant between both materials. The ProRoot MTA and tbe MTA-Angelus are material with appropriate biological properties and believe the ideal conditions so that it happens the repair of the periodontal tissue in dogs'teeth