Effects of Nd : YAG and Er : YAG lasers on the sealing of root canal fillings

Objective: the ability of the laser irradiation to promote the cleaning and disinfection of the radicular canal system has become this type of treatment in a viable and real alternative in endodontics. The purpose of this study was to evaluate the apical marginal sealing of root canal fillings after the irradiation with the laser of Nd:YAG or of Er:YAG. Materials and Methods: Forty-two human, extracted single-rooted teeth had their crowns sectioned and the root canals prepared with a no. 70 K-file. Then, they were dried and divided into three groups according to canal wall treatment: group 1: the canals were filled with EDTA for 3 min, followed by irrigation with 1% sodium hypochlorite solution; group 2: the canal walls were irradiated with Nd:YAG laser; and group 3: the canal walls were irradiated with Er:YAG laser. Afterwards, the root canals were obturated by the lateral condensation technique. The roots were externally waterproof, except in the apical foramen and immerged in 2% methylene blue aqueous solution during 48 hours. Results: the results showed that the largest infiltrations happened in the group 3-Er:YAG (7.3 mm), proceeded by the group 1-EDTA (1.6 mm) and by the group 2-Nd:YAG (0.6 mm). The group Er:YAG differed statistically of the others (p < 0.05). Conclusion: It was concluded that the Er:YAG laser intracanal irradiation previously to the root canal filling must be used with caution until future research is define the best parameters for it's use.

Cytotoxicity and Genotoxicity of Root Canal Sealers Based on Mineral Trioxide Aggregate

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Caracterização anatômica e química da folha e do sistema radicular de Hydrocotyle umbellata (Apiaceae)

A família Apiaceae (Umbelliferae), também denominada de pioneira das praias, é capaz de habitar locais de alto teor de salinidade, além de suportar a ação dos ventos e das ondas. O presente trabalho teve como objetivo o estudo da anatomia foliar e radicular e analisar constituintes químicos das folhas e do sistema radicular, caracterizando grupos químicos biologicamente ativos presentes nesses órgãos que permitam aplicações farmacológicas. O material foi coletado na região de Proteção Ambiental Iguape, Cananéia, Peruíbe. As folhas são dorsiventrais, com epiderme unisseriada, bordo regular, parênquima paliçádico com duas a três camadas e parênquima lacunoso com oito e nove camadas de células. É anfiestomática, apresentando grandes câmaras subestomáticas com maior incidência de estômatos na epiderme abaxial. O feixe vascular é colateral apresentando células de esclerênquima em forma de meia lua ao redor do xilema e do floema. O pecíolo apresenta contorno irregular, está envolvido por colênquima em toda sua extensão e apresenta grande quantidade de canais secretores entre os feixes vasculares. O rizoma apresenta contorno irregular com variação de 10 a 15 camadas de células de parênquima constituindo o córtex. O cilindro central é constituído por feixes colaterais delimitados pela endoderme. O periciclo é sinuoso e envolve totalmente os feixes vasculares. Sob a epiderme há uma faixa contínua de colênquima. A medula é constituída de células de parênquima de parede fina. H. umbellata apresentou triterpenos, saponinas, flavonóides, compostos poliacetilênicos e leucoceramidas. Folhas e rizomas apresentaram constituintes químicos semelhantes, com diferenças apenas na intensidade dos picos, o que denota diferença quantitativa entre as substâncias presentes. O rendimento do extrato do rizoma é menor que o rendimento das folhas.

Calagem na nutrição de cálcio e no desenvolvimento do sistema radicular da goiabeira

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Quantificação da função esfincteriana pela medida da capacidade de sustentação da pressão de contração voluntária do canal anal

RACIONAL: Tem sido demonstrado que a pressão máxima de contração voluntária e a pressão média de repouso não refletem a real situação clínica do paciente portador de incontinência fecal, não traduzem a realidade funcional do canal anal, além de poder estar comprometendo a conduta a ser tomada devido ao não-encaminhamento à terapêutica específica. OBJETIVO: Com a hipótese de que contrair e manter a contração é mais importante que simplesmente contrair, mesmo com pico momentaneamente elevado de pressão, analisou-se a capacidade de sustentação da pressão de contração voluntária do canal anal com o intuito de quantificar a função esfincteriana relativa à continência fecal. MATERIAL E MÉTODOS: Submeteram-se a exame manométrico anorretal 72 pacientes (56 mulheres) portadores de incontinência fecal de vários graus e 15 (9 mulheres) indivíduos continentes (normais), avaliando-se a pressão média de repouso, a pressão máxima de contração voluntária e a capacidade de sustentação da pressão de contração voluntária. RESULTADOS: Os indivíduos continentes apresentaram valores normais de pressão média de repouso e de pressão máxima de contração voluntária, além de adequada capacidade de sustentação da pressão de contração voluntária. Os pacientes incontinentes apresentaram pressão média de repouso e pressão máxima de contração voluntária com valores pressóricos normais ou abaixo do normal e perfil semelhante de capacidade de sustentação da pressão de contração voluntária, ou seja, moderada na fase inicial e ruim nas fases intermediária e final, com queda da mesma superior a 35% em 78% dos pacientes. A pressão máxima de contração voluntária apresenta excelente especificidade (100%) porém, sensibilidade baixa (46%) para incontinência fecal. Comparativamente, a capacidade de sustentação da pressão de contração voluntária apresenta elevadas especificidade (93%) e sensibilidade (78%) para incontinência fecal. Embora a pressão máxima de contração voluntária não indique falso-positivos, apresenta 72% de falso-negativos. A probabilidade deste fato acontecer com a medida de capacidade de sustentação da pressão de contração voluntária é, praticamente, 20% menor, valor estatisticamente significativo. CONCLUSÃO: O indicativo de função esfincteriana é melhor analisado pela capacidade de sustentação. A capacidade de sustentação traduz com mais exatidão, a capacidade funcional do canal anal em relação à continência voluntária, sendo isoladamente, melhor que a pressão máxima de contração voluntária.

Tissue response to an epoxy resin-based root canal sealer

The objective of the present study was to evaluate two different types of root canal sealers: AH Plus (an epoxy resin-based sealer) and Fill Canal (a zinc oxide-eugenol based sealer). A total of 34 root canals with vital pulp from dogs' premolars were used. After instrumentation, the root canals were filled with gutta-percha and AH Plus or gutta-percha and Fill Canal sealers using a classical technique of lateral condensation. After histological processing, the sections were stained with hematoxylineosin or Mallory's trichrome stain. Inflammatory cells or areas of necrosis were not associated with AH Plus. Hard tissue formation apically to the material was observed in 14 specimens. The Fill Canal sealer presented an inflammatory response of moderate intensity in the periapical region, mainly adjacent to the material.

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.

The induction of cytotoxicity, oxidative stress, and genotoxicity by root canal sealers in mammalian cells

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Comportamento dos tecidos periapicais de dentes de cães após a obturação de canal com Sealapex acrescido ou não de iodoformio.

Some endodontists use iodoform in Sealapex in order to rend it more radiopac. This procedure is empiric and for this reason we decided to observe, histologically, if the iodoform introduces some modification in the biological properties of Sealapex. Thirty root canals of dogs' teeth were overinstrumented and filled, by lateral condensation technique, with gutta percha points and Sealapex, with or without iodoform. The iodoform was added in two different proportions: 30 mg or 112 mg for one centimeter of the base and one centimeter of the catalyst of Sealapex. The pieces were removed for histological studies, 6 months after the treatment. The histological results showed that Sealapex encourages apical closure by cementum deposition and that the addition of iodoform does not change that biological property.

pH changes at the surface of root dentin when using root canal sealers containing calcium hydroxide

The purpose of this study was to investigate long-term pH changes in cavities prepared in root surface dentin of extracted teeth after obturation of the root canal with gutta-percha and a variety of sealers containing calcium hydroxide. After cleaning and shaping, root canals in 50 recently extracted, human single-rooted teeth were divided into five groups. Each of four groups was obturated with gutta-percha and either Sealapex, Sealer 26, Apexit, or CRCS, all of which contain calcium hydroxide. The remaining group served as the control and was not obturated with gutta-percha or sealer. Cavities were prepared in the facial surface of the roots in the cervical and middle regions. The pH was measured in these dentinal cavities at the initiation of the experiment, and 3, 7, 14, 21, 28, 45, 60, 90, and 120 days after obturation. Results indicate that the pH at the surface of the root does not become alkaline when calcium hydroxide cements are used as root canal sealers. Regardless of the sealer used, the observed pattern of pH change was not different from that seen in the control group of roots that were not treated with sealer. It is concluded that calcium hydroxide-containing cements, although suitable for use as root canal sealants, do not produce an alkaline pH at the root surface. If such a pH change is related to treatment of root resorption, these sealants do not contribute to this treatment. Copyright © 1996 by The American Association of Endodontists.

Apical leakage after root canal filling with an experimental calcium hydroxide gutta-percha point

This study was an in vitro analysis of the apical seal of root canals filled with an experimental calcium hydroxide gutta-percha point. One hundred and ten recently extracted human permanent teeth with a single root were used. The root canals were biomechanically prepared, and some received a dressing of calcium hydroxide for 7 days. Root canals not dressed were filled by the lateral condensation technique with either regular gutta-percha or calcium hydroxide gutta-percha points. The dressed root canals were filled with the same sealers and regular gutta-percha points. The specimens were placed into a 2% methylene blue dye solution under vacuum, and the apical leakage was linearly evaluated. The experimental groups with calcium hydroxide dressing and the one with calcium hydroxide gutta-percha points exhibited significantly (p < 0.05) less leakage than the groups filled with regular gutta-percha points. The results obtained indicated that calcium hydroxide guttapercha points produced an improvement in the apical sealing quality of the root canal filling. Copyright © 1996 by The American Association of Endodontists.

Calcium hydroxide root canal sealers: Evaluation of pH, calcium ion concentration and conductivity

The calcium hydroxide ionization of four root canal sealers (Sealapex, CRCS, Sealer 26, and Apexit) was studied by measuring conductivity and pH and by conducting atomic absorption spectrophotometry. Samples 6 mm in diameter and 15 mm long were prepared from these sealers. After setting and 48 h storage in a desiccator, five samples of each material were placed in 50 mL distilled water and analysed after 0,1,2,4, 6 and 24 h and 5, 15 and 30 days. The results showed that Sealapex was the root canal sealer showing the highest pH, ionic calcium and total calcium values (P<0.05) throughout the experimental period, followed by CRCS, Apexit and Sealer 26.

Effect of different root canal sealers on periapical repair of teeth with chronic periradicular periodontitis

Teeth with induced chronic periradicular periodontitis in dogs were root canal treated. After the biomechanical preparation, using K files and 5.25% sodium hypochlorite as the irrigant solution, all root canals were dressed with an antibacterial dressing based on calcium hydroxide, which was left in place for 7 days. After this time, the root canals were obturated with lateral condensation of cold gutta-percha with either a calcium hydroxide root canal filling material (Sealapex) or a zinc oxide-eugenol sealer (Fill Canal). After 270 days, histopathological analysis showed better apical and periapical repair in the teeth obturated with Sealapex (P < 0.05).

Reaction of dogs' teeth to root canal filling with mineral trioxide aggregate or a glass ionomer sealer

This study was conducted to observe the reaction of apical tissues of dogs' teeth after root canal filling with gutta-percha and mineral trioxide aggregate (MTA) or a glass ionomer (Ketac-Endo) as a sealer. The root canals were instrumented and filled by the lateral condensation technique with the sealers studied. Animals were killed 6 months later, and the specimens were removed and prepared for histological analysis. Results showed no inflammatory reaction of apical tissue and total closure of the apical foramen of all the teeth sealed with MTA. The teeth sealed with Ketac-Endo showed two cases of partial closure and different degrees of chronic inflammatory reaction. In conclusion, MTA exhibited better biological properties than Ketac-Endo. Copyright © 1999 by The American Association of Endodontists.

Evaluation of cell culture cytotoxicity of five root canal sealers

The cytotoxicity of four calcium hydroxide-based root canal sealers (Sealapex, CRCS, Apexit, and Sealer 26) and one zinc oxide-eugenol-based sealer (Fill Canal) was evaluated microscopically for morphological changes in rat peritoneal macrophages. The least cytotoxic sealer was Fill Canal, followed in increasing order of cytotoxicity by CRCS, Sealer 26, Apexit, and Sealapex. Copyright © 2000 by The American Association of Endodontists.