Removal of filling material using rotating or reciprocating systems with or without solvent: microCT analysis

Abstract This study evaluated by the efficacy of rotary and reciprocating systems to remove filling material by micro-CT. Sixty human canines were instrumented up to F3 by ProTaper Universal system and filled with AH Plus/ gutta-percha. Specimens were submitted to 1,200 thermal cycles, scanned by microCT SkyScan 1176 and randomly distributed in groups according to the filling material removal protocol (n = 10): ProTaper Universal, ProTaper Universal/xylol, ProTaper Next, ProTaper Next/xylol, Reciproc and Reciproc/xylol. After filling removal, specimens were analyzed by microCT to separately verify the presence of gutta-percha and sealer remnants. The data (mm3) were analyzed by two way ANOVA and Tukey´s test (5%). For the remaining gutta-percha, the use of xylol provided the highest values for Reciproc (7.60 ± 0.73), which was statistically different from the other groups (p < 0.05) that presented lower values and were statistically similar to each other (p > 0.05). For the remaining sealer, xylol provided the highest values (21.25 ± 6.94) different (p < 0.05) from the use of instruments alone (11.47 ± 9.45). ProTaper Next presented the lowest values (8.16 ± 1.37) for the remaining sealer, different (p < 0.05) from that of Reciproc (24.67 ± 6.32). The qualitative analysis revealed that all groups presented some remaining root filling material, with the highest volumes presented by Reciproc and Reciproc/xylol. In conclusion the rotary systems provided greater removal of filling material regardless of the use of xylol. The use of xylol negatively interfered with the action of the reciprocating system in the removal of the gutta-percha and sealer.

Bioética em Angola: experiência da Faculdade de Medicina de Malanje / Bioethics in Angola: experience of the Malanje Medical School / Bioética en Angola: experiencia de la Facultad de Medicina de Malanje

Resumo O desenvolvimento da bioética e da ética na investigação científica em África é relativamente incipiente, mas vem crescendo o interesse público pelo tema. Este artigo relata a experiência da Faculdade de Medicina de Malanje da Universidade Lueji A'Nkonde. São abordados eventos ocorridos na faculdade para o desenvolvimento integral da bioética, com destaque para a Conferência Internacional Sub-Regional sobre Ética da Investigação Científica, que deu origem à Declaração de Malanje, e a criação do Comitê de Bioética em Pesquisa. Enfim, conclui-se que os passos em prol desse campo do conhecimento representam indícios de sua implantação em Angola. No entanto, urgem ações governamentais de países das redes em Bioética na América Latina e Caribe para efetivar a cooperação Sul-Sul e cumprir todas as recomendações da Declaração de Malanje.

Abstract The current development of Bioethics and Ethics in scientific research in Africa is relatively incipient, but public interest in the subject is growing. We address the experience of the Malanje Medical School in the field of Bioethics in Angola. We summarize events at the Malanje Medical School of the Lueji A'Nkonde University for the Integral Development of Bioethics. One of its results was the Malanje Declaration. Another one was the creation of the Research Bioethics Committee of the Malanje Medical School. Finally, we consider the steps towards the Integral Development of Bioethics as evidence of its implantation in that country. However, there is need for governmental action in the countries involved in the mediation of Bioethics networks for Latin America and the Caribbean for the South-South cooperation objective and fulfilment of all the recommendations of the Malanje Declaration.

Resumen El desarrollo actual de la bioética y de la ética en la investigación científica en África es relativamente incipiente, pero viene creciendo el interés público en el tema. Este artículo relata la experiencia de la Facultad de Medicina de Malanje de la Universidad Lueji A'Nkonde. Se abordan los eventos que tuvieron lugar en la facultad para el desarrollo integral de la bioética, destacándose la Conferencia Internacional Subregional sobre Ética de la Investigación Científica, que dio origen a la Declaración de Malanje, y a la creación del Comité de Bioética en Investigación. Finalmente, se concluye que los pasos en pro de este campo del conocimiento representan indicios de su implantación en Angola. No obstante, urgen acciones gubernamentales de los países involucrados con las redes de Bioética en América Latina y el Caribe para efectivizar la cooperación Sur-Sur y cumplir todas las recomendaciones de la Declaración de Malanje.

Termos de esclarecimento e responsabilidade à luz da bioética de intervenção / Terms of clarification and accountability in the light of intervention bioethics / Formularios de esclarecimiento y responsabilidad a la luz de la bioética de intervención

Resumo No Brasil, o acesso aos medicamentos do Componente Especializado da Assistência Farmacêutica, no âmbito do Sistema Único de Saúde, ocorre mediante preenchimento e entrega do termo de esclarecimento e responsabilidade nas farmácias especializadas. Estes termos visam a obtenção do consentimento informado do paciente no que diz respeito ao tratamento medicamentoso oferecido. O estudo avaliou-os à luz do referencial teórico da bioética de intervenção com ênfase na garantia da autonomia do paciente e na sua proteção como ente vulnerável. Embora haja dispositivos que resguardem sua privacidade e forneçam informações relevantes para seu empoderamento na relação com o médico, os termos carecem de medidas protetivas nos casos em que ocorrem efeitos indesejáveis. Cabe, portanto, ao Estado fortalecê-los para garantir verdadeira autonomia dos pacientes, balizar sua vulnerabilidade e assegurar medidas de proteção em casos de episódios adversos.

Abstract In Brazil, access to medicines of the Specialized Pharmaceutical Care Program, within the scope of the Brazilian Unified Health System, depends on filling out and delivering the Clarification and Responsibility Form at specialized pharmacies. These forms are intended to obtain the patient´s informed consent concerning the medication being offered. The study evaluated them in the light of the theoretical reference of intervention bioethics, with emphasis on guaranteeing patient autonomy and protection as a vulnerable entity. Though the forms studied consider patient privacy and provide them with information relevant to their empowerment in dealing with doctors, the term lacks enough protective measures in cases where undesirable effects occur. Therefore, it is a State responsibility to strengthen them to guarantee true autonomy for patients, to identify their vulnerability and to ensure protective measures in cases of adverse event.

Resumen En Brasil, el acceso a los medicamentos del Componente Especializado de la Asistencia Farmacéutica, en el ámbito del Sistema Único de Salud, tiene lugar mediante diligenciamiento y entrega del Formulario de Esclarecimiento y Responsabilidad en las farmacias especializadas. Estos documentos procuran la obtención del consentimiento informado del paciente respecto del tratamiento medicamentoso a ser ofrecido. Este estudio los evaluó a la luz del marco teórico de la bioética de intervención con énfasis en la garantía de la autonomía del paciente y en su protección como ente vulnerable. Aunque haya dispositivos que resguarden la privacidad del paciente y proporcionen informaciones relevantes para su empoderamiento en la relación con el médico, los formularios carecen de medidas de protección en los casos de ocurrencia de efectos indeseables. Le compete, por lo tanto, al Estado fortalecerlos para garantizar una verdadera autonomía de los pacientes, demarcar su vulnerabilidad, y asegurar medidas de protección en casos de episodios adversos.

Influence of solvents on the bond strength of resin sealer to intraradicular dentin after retreatment

Abstract This study evaluated the removal of filling material with ProTaper Universal Rotary Retreatment system (PTR) combined with solvents and the influence of solvents on the bond strength (PBS) of sealer to intraradicular dentin after canal reobturation. Roots were endodontically treated and distributed to five groups (n = 12). The control group was not retreated. In the four experimental groups, canals were retreated with PTR alone or in combination with xylol, orange oil, and eucalyptol. After filling material removal, two specimens of each group were analysed by SEM and µCT to verify the presence of filling remnants on root canal walls. The other roots were reobturated and sectioned in 1-mm-thick dentin slices that were subjected to the push-out test. Data were analysed by two-way ANOVA and Tukey’s test (α = 0.05). SEM and µCT analysis revealed that all retreatment techniques left filling remnants on canal walls. The control group (3.47 ± 1.21) presented significantly higher (p < 0.05) PBS than the experimental groups. The groups retreated with PTR alone (2.59 ± 0.99) or combined with xylol (2.54 ± 0.77) and orange oil (2.32 ± 0.93) presented similar bond strength (p > 0.05), and differed significantly from the group with eucalyptol (1.89 ± 0.63). The solvents reduced the PBS of the sealer to dentin and no retreatment technique promoted complete removal of filling material.

Influence of the Resin Cement Thickness on the Push-Out Bond Strength of Glass Fiber Posts

Abstract The objective of the present study was to evaluate the influence of resin cement thickness on the bond strength of prefabricated and customized glass fiber posts after storage in distilled water. Thirty human uniradicular roots were treated endodontically. The roots were divided into 3 groups: THIN (thin cement layer) - post space preparation with #0.5 drill and cementation of #0.5 post; THICK (thick cement layer) - post space preparation with #1 drill and cementation of #0.5 post; and CUSTOM (customized cement layer) - post space preparation with #1 drill and cementation of a customized post (#0.5 glass fiber posts customized with resin composite). All posts were luted with self-adhesive resin cement. The push-out test was carried out after storage for 24 h and 90 days in distilled water at 37 °C. The data were analyzed with three-way ANOVA and Tukey's test (a=0.05). Bond strengths were significantly higher for CUSTOM (9.37 MPa), than for THIN (7.85 MPa) and THICK (7.07 MPa), which were statistically similar. Considering the thirds, the bond strength varied in the sequence: apical (7.13 MPa) < middle (8.22 MPa) = coronal (8.94 MPa). Bond strength for 24 h storage was significantly higher (8.80 MPa) than for 90-day storage (7.40 MPa). It may be concluded that the thickness of resin cement influenced the bond strength of glass fiber posts. The customized posts presented higher bond strength. Storage in water for 90 days affected negatively the values of bond strength, especially for thick cement layers in the apical third.

Resumo O objetivo deste estudo foi avaliar a influência da espessura da linha de cimento na resistência de união de pinos de fibra de vidro após armazenamento em água destilada. Trinta dentes humanos hígidos unirradiculares tiveram os canais tratados endodonticamente. As raízes foram distribuídas em três grupos: THIN (linha de cimento fina): conduto preparado com broca 0,5 e cimentação de pino 0,5; THICK (linha de cimento espessa): conduto preparado com broca 1 e cimentação de pino 0,5; e CUSTOM (linha de cimento personalizada): conduto preparado com broca 1 e cimentação de pino personalizada (pino 0,5 personalizado com resina composta). Os pinos foram cimentados com cimento auto-adesivo. Após armazenamento das raízes em água destilada a 37 °C por 24 h e 90 dias, o teste de cisalhamento por extrusão push-out foi realizado. Os resultados foram analisados estatisticamente por ANOVA a três fatores e teste de Tukey (a=0,05). A resistência de união foi significativamente maior para CUSTOM (9,37 MPa), do que para THIN (7,85 MPa) e THICK (7,07 MPa), que foram semelhantes entre si. Considerando-se os terços radiculares, a resistência de união variou na sequência: apical (7,13 MPa) < médio (8,22 MPa) = coronal (8,94 MPa). A resistência de união após 24 h de armazenamento em água foi significativamente maior (8,80 MPa) do que para 90 dias (7,40 MPa). Pode-se concluir que houve influência da espessura da linha de cimento na resistência de união de pinos de fibra de vidro, sendo que o uso de pinos personalizados apresentou maiores valores de resistência de união. O armazenamento em água por 90 dias afetou negativamente os valores de resistência de união, especialmente no terço apical, no grupo com linha de cimento mais espessa.

Effect of thermoplastic filling techniques on the push-out strength of root sealing materials

This study evaluates the effect of two thermoplastic obturation systems (MicroSeal and Obtura II) on bond strength of different sealers to intraradicular dentin. Sixty root canals of human canines were prepared using ProTaper rotary files (crown-down technique) and irrigated with 2.5% sodium hypochlorite and 17% EDTA. The root canals were filled by MicroSeal, Obtura II, or lateral compaction techniques using AH Plus and Epiphany SE. 1.5 mm thick root slices were subjected to the push-out test. ANOVA and Tukey's test showed that the bond strength values (MPa) observed in the groups obturated with MicroSeal (2.96 ± 2.72) and Obtura II (2.68 ± 2.18) did not significantly differ from each other (p > 0.05) but were significantly higher than that observed in the group obturated with lateral condensation (2.01 ± 1.48; p < 0.05). There were no statistically significant differences in strength (p > 0.05) among the root canal thirds (cervical: 2.44 ± 2.03; middle: 2.50 ± 2.27; and apical: 2.70 ± 2.34). Adhesive failures were predominant (60%) in all groups. In conclusion, MicroSeal and Obtura II techniques, using AH plus sealer, increased the resistance to displacement of the filling material, when compared with lateral compaction. Moreover, when used with Epiphany SE, these obturation systems did not affect the bond strength of the material to root dentin.

Non-Pedicled Buccal Fat Pad Grafts to Treatment for Class I and II Gingival Recessions: A Clinical Trial

The aim of this study was to analyze the transplant efficiency of non-pedicled buccal fat pad graft (BFPG) for the treatment of Miller Class I or II gingival recessions (GRs) and to compare these results with those of subepithelial connective tissue graft (SCTG), which is considered the gold standard. Twelve patients with Miller Class I or II (≥2 mm) bilateral recessions in maxillary premolars or canines were selected. Recessions were randomly assigned to receive SCTG or BFPG. The clinical parameters evaluated at baseline and at 1, 3, and 6 months postoperatively included gingival index, plaque index, probing depth, GR, clinical attachment level, width of keratinized tissue, thickness of keratinized tissue and gingival margin to the acrylic guide. None of the evaluated clinical parameters differed significantly between the groups. At all evaluated postoperative time-points, both groups exhibited statistically significant differences in GR and gingival margin to the acrylic guide compared to baseline. Six months after surgery, the mean percentages of root coverage were 67.5% and 87.5% in the BFPG and SCTG groups respectively. In both groups, complete root coverage was observed in 50% of cases 6 months after surgery. The results presented herein indicate that the use of BFPG transplant has clinical similarities with SCTG and both may be considered as clinically successful methods for treating Miller Class I and II GRs.

Resumo O objetivo deste estudo foi analisar a eficiência do transplante do enxerto de tecido adiposo bucal não pediculado (ETAB) para o tratamento de recessões gengivais Classe I e II de Miller e comparar seus resultados com o enxerto de tecido conjuntivo (ETC), que é considerado o enxerto padrão ouro. Foram selecionados 12 pacientes com recessões gengivais bilaterais Classe I e II de Miller presentes em canino ou pré-molares maxilares. As recessões foram randomizadas para receber um dos dois tratamentos ETAB ou ETC. Os parâmetros clínicos avaliados no baseline e com 1, 3 e 6 meses de pós-operatório foram o índice gengival, índice de placa, profundidade de sondagem, recessão gengival (RG), nível clinico de inserção, espessura e largura de tecido queratinizado e a medida da margem gengival ao guia de acrílico (MG-GA). Os resultados mostraram que não houve diferença estatisticamente significativa entre os grupos em nenhum dos parâmetros clínicos avaliados. Os parâmetros clínicos de RG e MG-GA, em ambos os grupos, apresentaram diferença estatisticamente significativa nos 3 períodos pós-operatórios em relação ao baseline. Aos 6 meses de pós-operatório, a média percentual de recobrimento radicular foi de 67,5% e 87,5% para o grupo ETAB e ETC respectivamente. Em ambos os grupos o recobrimento radicular completo foi em 50% dos casos após 6 meses de pós-operatório. Pode-se concluir que o transplante do ETAB apresentou similaridades clínicas com o ETC e ambos os tratamentos podem ser considerados de sucesso clínico para o tratamento de RGs Classe I e II de Miller.

Postgraduate students' knowledge on oral health

Objective:This study aimed to evaluate the oral health knowledge of postgraduate students comparing the results according to the area (exact sciences, health and humanities). Material and methods: The descriptive study consisted of a questionnaire with 12 open and closed questions applied to 120 students enrolled in post-graduation courses at the University of Ribeirão Preto. All responses were analyzed using descriptive statistics and the comparison among the student's areas was performed using Chi-square test with 5% significance level of significance. Results: The results showed that the average age of participants was 30.8 years, but with statistically significant difference among the three areas (humanities - 32.8 years; health - 27 and exact - 30.8 years). The last visit to the dentist in the last 12 months for 48.7% of the graduates in the humanities, 69.0% in the health area and 74.4% in the exact area, in a private practice (43.6% of Human, 71.4% health and 79.5% exact area) (p<0.05). About what is plaque, 25.6% of graduates in humanities, 23.8% in health area, and 17.9% in exacts could not answer. Concerning to plaque removal, 43.6% of the humanity and health area graduate thought that only the dentist can remove it. Dental caries primarily occurs because of poor hygiene for 59.0% of the graduates in the humanities, 81.0% of health care and 69.2% of the exact area. About fluoride, most knew about their usefulness (prevention and protection), but 31.0% of the graduates in healthcare associated fluoride to cleaning. Statistically significant differences in the questions about knowledge were found. Conclusion: It was concluded that the knowledge presented by graduates was limited and incomplete, regardless of the area.

Non-Pedicled Buccal Fat Pad Grafts to Treatment for Class I and II Gingival Recessions: A Clinical Trial.

The aim of this study was to analyze the transplant efficiency of non-pedicled buccal fat pad graft (BFPG) for the treatment of Miller Class I or II gingival recessions (GRs) and to compare these results with those of subepithelial connective tissue graft (SCTG), which is considered the gold standard. Twelve patients with Miller Class I or II (≥2 mm) bilateral recessions in maxillary premolars or canines were selected. Recessions were randomly assigned to receive SCTG or BFPG. The clinical parameters evaluated at baseline and at 1, 3, and 6 months postoperatively included gingival index, plaque index, probing depth, GR, clinical attachment level, width of keratinized tissue, thickness of keratinized tissue and gingival margin to the acrylic guide. None of the evaluated clinical parameters differed significantly between the groups. At all evaluated postoperative time-points, both groups exhibited statistically significant differences in GR and gingival margin to the acrylic guide compared to baseline. Six months after surgery, the mean percentages of root coverage were 67.5% and 87.5% in the BFPG and SCTG groups respectively. In both groups, complete root coverage was observed in 50% of cases 6 months after surgery. The results presented herein indicate that the use of BFPG transplant has clinical similarities with SCTG and both may be considered as clinically successful methods for treating Miller Class I and II GRs.

Computed tomography evaluation of rotary systems on the root canal transportation and centering ability

Abstract: The endodontic preparation of curved and narrow root canals is challenging, with a tendency for the prepared canal to deviate away from its natural axis. The aim of this study was to evaluate, by cone-beam computed tomography, the transportation and centering ability of curved mesiobuccal canals in maxillary molars after biomechanical preparation with different nickel-titanium (NiTi) rotary systems. Forty teeth with angles of curvature ranging from 20° to 40° and radii between 5.0 mm and 10.0 mm were selected and assigned into four groups (n = 10), according to the biomechanical preparative system used: Hero 642 (HR), Liberator (LB), ProTaper (PT), and Twisted File (TF). The specimens were inserted into an acrylic device and scanned with computed tomography prior to, and following, instrumentation at 3, 6 and 9 mm from the root apex. The canal degree of transportation and centering ability were calculated and analyzed using one-way ANOVA and Tukey’s tests (α = 0.05). The results demonstrated no significant difference (p> 0.05) in shaping ability among the rotary systems. The mean canal transportation was: -0.049 ± 0.083 mm (HR); -0.004 ± 0.044 mm (LB); -0.003 ± 0.064 mm (PT); -0.021 ± 0.064 mm (TF). The mean canal centering ability was: -0.093 ± 0.147 mm (HR); -0.001 ± 0.100 mm (LB); -0.002 ± 0.134 mm (PT); -0.033 ± 0.133 mm (TF). Also, there was no significant difference among the root segments (p> 0.05). It was concluded that the Hero 642, Liberator, ProTaper, and Twisted File rotary systems could be safely used in curved canal instrumentation, resulting in satisfactory preservation of the original canal shape.

Comparison of Two Techniques for Selection of Master Gutta-Percha Cone Using Micro-Computed Tomography

This study used micro-computed tomography (micro-CT) to evaluate the fit of the master gutta-percha cone at time of cone fit, gutta-percha volume in the filling material, and the filling material volume in relation to the canal at the apical limit of the working length. Root canals of 20 maxillary central incisors were prepared with rotary instruments and distributed into two groups (n=10). The gutta-percha cone tip was either plasticized (apical thermal impression technique - ATI) or not (conventional technique - CT), and its apical fit was checked. The apical 1 mm of working length was examined with a micro-CT, canals were filled with gutta-percha and sealer, and new micro-CT scans were obtained. In CT, gutta-percha filled 35.83 ± 15.05% of the canal at cone selection and 38.72 ± 11.64% after filling. In ATI, these values were 23.14 ± 7.74% and 26.98 ± 20.40%, respectively. Gutta-percha volume in the filling material, and filling material volume in relation to the canal were, respectively, 61.28 ± 11.64% and 87.76 ± 9.98% for CT, and 73.00 ± 20.41% and 89.96 ± 9.08% for ATI. No significant difference was found between cone selection and after canal filling, for either CT (p=0.593) or ATI (p=0.4975). The techniques did not differ significantly with respect to gutta-percha volume in the filling material (p=0.132) and filling material volume in relation to the canal (p=0.612). An ideal fit of the master gutta-percha cone at working length was not achieved regardless of the cone selection technique, and the material-filled area was similar for both techniques.

Este estudo utilizou microtomografia computadorizada (micro-CT) para avaliar a adaptação do cone de guta-percha no momento da sua seleção, o volume de guta-percha no material obturador, e o volume do material obturador em relação ao canal no limite apical do comprimento de trabalho. Canais radiculares de 20 incisivos centrais superiores foram preparados com instrumentos rotatórios e distribuídos em dois grupos (n=10). A ponta do cone de guta-percha foi plastificada (técnica de impressão térmica apical - TIT) ou não (técnica convencional - TC), e seu ajuste apical foi verificado. O milimetro apical do comprimento de trabalho foi examinado em micro-CT, os canais foram preenchidos com guta-percha e cimento, e novas imagens em micro-CT foram obtidas. Na TC, a guta-percha preencheu 35,83 ± 15,05% do canal no momento da seleção do cone e 38,72 ± 11,64% após a obturação. Na TIT, estes valores foram de 23,14 ± 7,74% e 26,98 ± 20,40%, respectivamente. O volume de guta-percha no material obturador, e o volume do material obturador em relação ao canal, foram, respectivamente, 61,28 ± 11,64% e 87,76 ± 9,98% para a TC, e 73,00 ± 20,41% e 89,96 ± 9,08% para TIT. Não foi encontrada diferença significativa entre a seleção do cone e depois o preenchimento do canal para ambas as técnicas, TC (p =0,593) ou TIT (p=0,4975). As técnicas não diferiram significativamente com respeito ao volume de guta-percha no material obturador (p=0,132), e volume de preenchimento de material em relação ao canal (p=0,612). Um ajuste ideal do cone principal de guta-percha cone no seu comprimento de trabalho não foi alcançado, independentemente da técnica de seleção empregada, e a area preenchida pelo material obturador foi semelhante para ambas as técnicas.

Microhardness of radicular dentin treated with 980-nm diode laser and different irrigant solutions.

OBJECTIVE: The aim of this study was to evaluate the microhardness of radicular dentin after treatment with 980-nm diode laser and different irrigant solutions. BACKGROUND DATA: There are few reports of the consequences of diode laser irradiation emitted at 980 nm on the mechanical properties of dentin. METHODS: Seventy-two single canal, human canines with complete root formation were randomly distributed among three groups (n=24), according to the irrigant solution used in the biomechanical preparation: distilled water; 1% NaOCl; and, 1% NaOCl + 17% EDTA. These groups subsequently were divided into three subgroups (n=8), according to the diode laser parameter: no irradiation (control); 1.5 W/100 Hz; and 3.0 W/100 Hz. Laser was applied with helicoidal movements for 20 sec. Roots were sectioned in slices and the fragment corresponding to the middle third was submitted to the microhardness test (KHN) at depths of 30, 90, 150, and 300 µm. RESULTS: ANOVA and Tukey tests showed that the microhardness of the groups irradiated with 1.5 W/100 Hz (49.7±11.2) and 3.0 W/100 Hz (50.6±11.9) were statistically similar to each other (p>0.05) and different (p<0.05) from the non-irradiated group (45.0±9.7). Higher microhardness values were obtained at 150 µm (49.2±11.0) and 300 µm (52.3±11.3) which were similar among themselves and different (p<0.05) only at the depth of 30 µm (44.4±10.5). No differences were found among the irrigant solutions (p>0.05). CONCLUSIONS: The microhardness of the radicular dentin increased after irradiation with 980-nm diode laser.

Biocompatibility of sealers used in apical surgery: a histological study in rat subcutaneous tissue.

The aim of this study was to evaluate the biocompatibility of sealers used in apical surgery in rat subcutaneous tissue. Sterile polyethylene tubes were filled with the following sealers: Sealapex, Sealapex with addition of zinc oxide, Sealer 26, Sealer 26 with thicker consistency (greater powder-to-resin ratio) and White MTA. The tubes were implanted in the dorsum of male rats and after 7, 21 and 42 days, the animals were killed, obtaining 5 specimens for each sealer in each evaluation period. The lateral surface of the tube was used as negative control. The inflammatory reaction to contact with the sealers was classified as absent, mild, moderate and severe. At 7 days, all sealers caused similar inflammatory reactions in the connective tissue of the animals, with most specimens presenting a moderate to intense chronic inflammatory reaction, with presence of multinucleated giant cells. At 21 days, Sealer 26 and Sealer 26 with thicker consistency presented more intense inflammatory reaction (p=0.004), whereas after 42 days, the inflammatory reaction ranged from absent to mild with statistically similar results for both materials (p=0.08). Except for MTA, all sealers presented foreign-body granulomatous reaction at 42 days. All sealers but Sealapex presented a statistically significant decrease of the inflammatory reaction over time. In conclusion, all sealers caused moderate to severe inflammation in the earlier evaluation period. However, Sealer 26 and Sealer 26 with thicker consistency caused more intense inflammatory reactions after 21 days of contact with the tissues and no granulomatous reaction was observed for MTA at the final period of analysis.

Microhardness of intracoronal dentin exposed to bleaching and fluoride treatment.

OBJECTIVES: The aim of this study was to assess the surface microhardness (SMH) of intracoronal dentin exposed to 38% hydrogen peroxide (HP) light-activated or not and to 2% sodium fluoride gel (F2%) or 5% varnish (F5%). STUDY DESIGN: Intracoronal dentin specimens were exposed to bleaching (B), bleaching and light activation (BL), or no bleaching (NB), followed by F2%, F5%, or no exposure (NF). SMH test was performed. Four specimens of each group were analyzed by scanning electron microscopy (SEM). RESULTS: Analysis of variance and Tukey test (α = 5%) showed higher SMH of NB than BL or B. Specimens exposed to F5% presented the highest SMH and differed from F2% and NF. BL + NF yielded inferior SMH and was similar to B + NF, BL + F2%, B + F2%, BL + F5%, and NB + NF. NB + F5% showed superior values and did not differ from NB + F2%, B + F5%, and NB + NF. CONCLUSIONS: Bleaching with 38% HP, light-activated or not, reduced the SMH of intracoronal dentin. F5% provided SMH to the level of unbleached specimens.

Biocompatibility of sealers used in apical surgery: a histological study in rat subcutaneous tissue

The aim of this study was to evaluate the biocompatibility of sealers used in apical surgery in rat subcutaneous tissue. Sterile polyethylene tubes were filled with the following sealers: Sealapex, Sealapex with addition of zinc oxide, Sealer 26, Sealer 26 with thicker consistency (greater powder-to-resin ratio) and White MTA. The tubes were implanted in the dorsum of male rats and after 7, 21 and 42 days, the animals were killed, obtaining 5 specimens for each sealer in each evaluation period. The lateral surface of the tube was used as negative control. The inflammatory reaction to contact with the sealers was classified as absent, mild, moderate and severe. At 7 days, all sealers caused similar inflammatory reactions in the connective tissue of the animals, with most specimens presenting a moderate to intense chronic inflammatory reaction, with presence of multinucleated giant cells. At 21 days, Sealer 26 and Sealer 26 with thicker consistency presented more intense inflammatory reaction (p=0.004), whereas after 42 days, the inflammatory reaction ranged from absent to mild with statistically similar results for both materials (p=0.08). Except for MTA, all sealers presented foreign-body granulomatous reaction at 42 days. All sealers but Sealapex presented a statistically significant decrease of the inflammatory reaction over time. In conclusion, all sealers caused moderate to severe inflammation in the earlier evaluation period. However, Sealer 26 and Sealer 26 with thicker consistency caused more intense inflammatory reactions after 21 days of contact with the tissues and no granulomatous reaction was observed for MTA at the final period of analysis.

O objetivo deste estudo foi avaliar a biocompatibilidade de cimentos utilizados em cirurgia apical, em tecidos subcutâneos de ratos. Tubos de polietileno esterilizados foram preenchidos com os seguintes cimentos: Sealapex, Sealapex acrescido de óxido de zinco, Sealer 26, Sealer 26 espessado (maior proporção pó:resina) e MTA branco. Os tubos foram implantados no dorso de ratos machos e após 7, 21 e 42 dias, os animais foram mortos, obtendo 5 amostras por cimento em cada período analisado. A superfície lateral do tubo foi utilizada como controle negativo. A reação inflamatória em contato com os cimentos foram classificadas como ausente, leve, moderada e severa. Aos 7 dias, todos os cimentos induziram reações inflamatórias similares no tecido conjuntivo dos animais, com a maioria dos espécimes apresentando reação inflamatória crônica de moderada a intensa, com presença de células gigantes multinucleadas. Aos 21 dias, Sealer 26 e Sealer 26 espessado apresentaram reação inflamatória mais intensa (p=0,004), enquanto após 42 dias, a reação inflamatória variou de ausente a leve, com resultados estatisticamente semelhantes para ambos materiais (p=0,08). Com exceção do grupo MTA, todos os cimentos apresentavam reação granulomatosa de corpo estranho após 42 dias. Todos os grupos, exceto o Sealapex, apresentaram redução estatisticamente significante dos índices inflamatórios ao longo do tempo. Conclui-se que todos os cimentos induziram reação inflamatória de moderada a intensa no período inicial de análise. Entretanto, Sealer 26 e Sealer 26 espessado apresentaram reação inflamatória mais intensa após 21 dias de contato com os tecidos e reação granulomatosa não foi observada no grupo MTA no período final de análise.

Effect of bleaching protocols with 38 percent hydrogen peroxide and post-bleaching times on dentin bond strength

This study assessed the effect of bleaching protocols with 38 percent hydrogen peroxide (HP) and post-bleaching times on shear bond strength of a composite resin to dentin. One-hundred slabs of intracoronary dentin were included and randomly assigned into 2 groups according to the bleaching protocol: HP (2 applications of 10 min each) and HP activated by LED laser (2 applications of 10 min each/45 s of light activation). Groups were subdivided according to the post-bleaching time (n=10): 1 day, 3 days, 7 days, 10 days and 14 days. The control group was unbleached and restored (n=10). The specimens were restored with Single Bond adhesive system/Filtek Z250 resin using a polytetrafluorethylene matrix and were submitted to the shear bond strength testa after 24 h,. Data were analyzed by ANOVA and Tukey's test (α=0.05). Unbleached group (0.283 ± 0.134) had the highest bond strength and was statistically similar (p>0.05) to HP/10 days (0.278 ± 0.064), HP + LED laser/10 days (0.280 ± 0.078), HP/14 days (0.281 ± 0.104), HP + LED laser/14 days (0.277 ± 0.093). Lower bond strength were verified in HP/1 day (0.082 ± 0.012), HP/3 days (0.079 ± 0.013), HP + LED laser/1 day (0.073 ± 0.018) and HP + LED laser/3 days (0.080 ± 0.015), which were statistically similar (p>0.05). HP/7 days (0.184 ± 0.154) and HP + LED laser/7 days (0.169 ± 0.102) had intermediate values (p<0.05). The restorative procedure of intracoronary dentin bleached with 38 percent HP with or without the use of light source should be performed after at least 10 days after the bleaching treatment.

Este estudo avaliou o efeito de protocolos de clareamento com peróxido de hidrogênio 38 por cento (PH) e tempos pós-clareamento na resistência ao cisalhamento de uma resina composta á dentina. Cem fragmentos de dentina intracoronária foram incluídos e distribuídos aleatoriamente em 2 grupos experimentais de acordo com o protocolo de clareamento: PH (2 aplicações de 10 min cada) e HP ativado por LED laser (2 aplicações de 10 min cada/45 s de ativação pela luz). Os grupos foram subdivididos de acordo com o tempo pós-clareamento (n=10): 1 dia, 3 dias, 7 dias, 10 dias e 14 dias. O grupo controle não foi clareado e apenas restaurado (n=10). Os espécimes foram restaurados com sistema adesivo Single Bond/resina Filtek Z250 usando matriz de teflon. Após 24 h, foram submetidos ao teste de cisalhamento. Os dados foram analisados por ANOVA e teste de Tukey (α=0,05). O grupo não clareado (0,283 ± 0,134) apresentou a maior resistência de união e foi estatisticamente semelhante (p>0,05) ao PH- 10 dias (0,278 ± 0,064), PH + LED laser/10 dias (0,280 ± 0,078), PH/14 dias (0,281 ± 0,104), PH + LED laser/14 dias (0,277 ± 0,093). Resistência de união inferior foram verificadas para PH/1 dia (0,082 ± 0,012), PH/3 dias (0,079 ± 0,013), PH + LED laser/1 dia (0,073 ± 0,018) e PH + LED laser/3 dias (0,080 ± 0,015), que foram estatisticamente semelhantes entre si (p>0,05). HP/7 dias (0,184 ± 0,154) e PH + LED laser/7 dias (0,169 ± 0,102) apresentaram valores intermediários (p<0,05). O procedimento restaurador da dentina intracoronária clareada com peróxido de hidrogênio 38 por cento, com ou sem o uso de fonte de luz, deve ser realizado pelo menos após 10 dias do tratamento clareador.

Apical microleakage and SEM analysis of dentin surface after 980 nm diode laser irradiation

This study evaluated the effect of 980-nm diode laser on apical microleakage and intraradicular dentin morphology. Roots of 110 mandibular incisors were used in the study: 92 for microleakage test and 18 for scanning electron microscopy (SEM). Roots were randomly assigned to 3 groups according to the irrigating solution (water, NaOCl and NaOCl/EDTA) and were divided into 3 subgroups according to the laser irradiation protocol (without irradiation, irradiated at 1.5 W and irradiated at 3.0 W). Two specimens of each subgroup were prepared for SEM. The remaining roots were filled with AH Plus and gutta-percha. Apical leakage was assessed by ink penetration and data were analyzed statistically by ANOVA and Tukey-Krammer test (α=0.05). SEM analysis showed intensification of changes with increase of laser power as well as variations according to the irrigating solution. Modified smear layer was observed in specimens treated with water and irradiated with laser. Roots irrigated with NaOCl/EDTA had lower levels of infiltration (0.17 ± 0.18 mm) differing significantly (p<0.05) from those of roots irrigated with water (0.34 ± 0.30 mm), but similar (p>0.05) to those irrigated with NaOCl (0.28 ± 0.29 mm). Non-irradiated roots had lower levels of infiltration (0.10 ± 0.14 mm), differing (p<0.05) from those irradiated at 1.5 W (0.32 ± 0.22 mm) and 3.0 W (0.37 ± 0.32 mm). The 980 nm diode laser modified dentin morphology and increased apical microleakage.

Este estudo avaliou o efeito do laser de diodo 980 nm na microinfiltração apical e na morfologia intrarradicular da dentina. Raízes de 110 incisivos inferiores foram utilizadas no estudo: 92 para o teste de microinfiltração e 18 para microscopia eletrônica de varredura (MEV). As raízes foram divididas em 3 grupos de acordo com a solução irrigante (água, NaOCl e NaOCl/EDTA) e subdivididas em 3 de acordo com a irradiação laser (sem irradiação, irradiados com 1,5 W e irradiados com 3,0 W). Duas amostras de cada subgrupo foram preparadas para MEV. As raízes restantes foram preenchidas com AH Plus e guta percha. A infiltração apical foi avaliada nas raízes por meio da penetração do corante e os dados foram analisados por ANOVA e teste de Tukey-Krammer (α=0,05). Os resultados da MEV mostraram intensificação das mudanças quando se aumentou a potência do laser e variações de acordo com a solução irrigadora. Camada de smear modificada foi observada em espécimes tratados com água e irradiados com laser. Raízes irrigadas com NaOCl/EDTA tiveram níveis menores de infiltração (0,17 ± 0,18 mm) estatisticamente diferente (p<0,05) das raízes irrigadas com água (0,34 ± 0,30 mm), mas semelhante (p>0,05) aos irrigados com NaOCl (0,28 ± 0,29 mm). As raízes não irradiadas tiveram níveis menores de infiltração (0,10 ± 0,14 mm), diferente (p<0,05) de 1,5 W (0,32 ± 0,22 mm) e 3.0 W (0,37 ± 0,32 mm). O laser de diodo 980 nm alterou a morfologia da dentina e aumentou a infiltração marginal apical.

Fracture resistance of teeth subjected to internal bleaching and restored with different procedures

This study evaluated the fracture resistance of teeth submitted to internal bleaching and restored with different procedures. Forty maxillary incisors were endodontically treated and assigned to 4 groups (n=10): G1- restored with composite resin (CR), G2- bleached with hydrogen peroxide (HP) and restored with CR, G3- restored with CR and fiberglass posts (CR + posts) and G4- bleached and restored with CR + posts. HP was applied in the buccal surface and pulp chamber 3 times at each one of 2 sessions with an interval of 7 days between them. Additional 10 sound incisors were subjected to fracture strength test (gold standard). The fracture strength (kN) was determined in an Instron machine. Data were analyzed by ANOVA and Tukey-Kramer test (α=0.05). The untreated teeth (gold standard) showed the highest (p<0.05) fracture strength (0.43 ± 0.16). Teeth restored with CR (G1) without internal bleaching had the lowest (p<0.05) fracture strength (0.23 ± 0.11). Teeth bleached and restored with CR (G2) (0.26 ± 0.10), restored with CR + posts ithout internal bleaching (G3) (0.31 ± 0.17) and, bleached and restored with CR + posts (G4) (0.33 ± 0.12) had intermediate values, sometimes similar to the group with the highest value, sometimes similar to the group with the lowest value. In conclusion, as far as the fracture strength is concerned, teeth subjected to internal bleaching can be restored with composite resin alone, as the use of posts in these teeth did not increase their resistance.

Este estudo avaliou a resistência à fratura de dentes submetidos ao clareamento interno restaurados com diferentes procedimentos. Quarenta incisivos superiores foram tratados endodonticamente e divididos em 4 grupos (n = 10): G1- restaurados com resina composta (RC), G2- clareados com peróxido de hidrogênio (PH) e restaurados com o RC, G3- restaurado com RC e pinos de fibra de vidro (RC + pinos) e G4- clareados e restaurados com RC + pinos. O PH foi aplicado na superfície vestibular e câmara pulpar 3 vezes por sessão, por 2 sessões com intervalo de 7 dias entre elas. Dez dentes hígidos adicionais foram submetidos a teste fratura (padrão ouro). A resistência à fratura (kN) foi determinada em máquina Instron. Os dados foram analisados por Análise de Variânica e teste de Tukey-Krammer (α= 0,05). Os dentes não tratados (padrão ouro) apresentaram a maior resistência à fratura (0,43 ± 0,16) (p <0,05). Os dentes restaurados com RC (G1) apresentaram a menor resistência à fratura (0,23 ± 0,11) (p <0,05). Os dentes clareados e restaurados com RC (G2) (0,26 ± 0,10), restaurado com RC + pinos (G3) (0,31 ± 0,17) e os clareados e restaurados com RC + pinos (G4) (0,33 ± 0,12) apresentaram valores intermediários, ora semelhantes ao do grupo com o maior valor, ora similares ao grupo de valores mais baixos. Pode-se concluir que os dentes submetidos ao clareamento interno podem ser restaurados com apenas resina composta.

Adhesion of endodontic sealers to human root dentine submitted to different surface treatments.

OBJECTIVE: To evaluate the adhesion of the endodontic sealers Epiphany, Apexit Plus, and AH Plus to root canal dentin submitted to different surface treatments, by using the push-out test. METHODS: One hundred twenty-eight root cylinders obtained from maxillary canines were embedded in acrylic resin, had the canals prepared, and were randomly assigned to four groups (n = 32), according to root dentin treatment: (I) distilled water (control), (II) 17% EDTAC, (III) 1% NaOCl and (IV) Er:YAG laser with 16-Hz, 400-mJ input (240-mJ output) and 0.32-J/cm(2) energy density. Each group was divided into four subgroups (n = 8) filled with Epiphany (either dispensed from the automix syringe supplied by the manufacturer or prepared by hand mixing), Apexit Plus, or AH Plus. Data (MPa) were analyzed by ANOVA and Tukey's test. RESULTS: A statistically significant difference (p < 0.01) was found among the root-canal sealers, except for the Epiphany subgroups, which had statistically similar results to each other (p > 0.01): AH Plus (4.77 +/- 0.85), Epiphany/hand mixed (3.06 +/- 1.34), Epiphany/automix syringe (2.68 +/- 1.35), and Apexit Plus (1.22 +/- 0.33). A significant difference (p < 0.01) was found among the dentin surface treatments. The highest adhesion values were obtained with AH Plus when root dentin was treated with Er:YAG laser and 17% EDTAC. Epiphany sealer presented the lowest adhesion values to root dentin treated with 17% EDTAC. CONCLUSIONS: The resin-based sealers had different adhesive behaviors, depending on the treatment of root canal walls. The mode of preparation of Epiphany (automix syringe or hand mixing) did not influence sealer adhesion to root dentin.

Effect of eugenol-based endodontic sealer on the adhesion of intraradicular posts cemented after different periods

OBJECTIVE: This study evaluated in vitro the influence of an eugenol-based sealer (EndoFill) on the retention of stainless steel prefabricated posts cemented with zinc phosphate and resin-based (Panavia F) cements after different periods of root canal obturation, using the pull-out test. MATERIAL AND METHODS: Sixty upper canines were decoronated and the roots were embedded in resin blocks. The specimens were distributed into 3 groups, according to the period elapsed between canal obturation and post cementation: Group I - immediately; Group II - 72 h and Group III - 4 months. The groups were subdivided according to the type of cement used for post cementation: A - zinc phosphate and B - Panavia F. Following the experimental periods, specimens were subjected to pullout test in an Instron machine with application of tensile force at a crosshead speed of 0.5 mm/min until post dislodgement. The maximum forces required for post removal were recorded (kN) and means were subjected to statistical analysis by 2-way ANOVA and Tukey-Kramer test (á=0.001) RESULTS: There were statistically significant differences (p<0.01) between the posts cemented with zinc phosphate cement (0.2112 kN) and Panavia F (0.0501 kN). However, no statistically significant differences (p>0.05) were found between the three post cementation periods, regardless of the cement. CONCLUSIONS: It was concluded that the eugenol-based sealer influenced the tensile strength of the posts cemented with the resin cement, but had no influence on the time waited between root canal obturation and post space preparation/post cementation.