Effect of Root Repair Materials and Bioactive Glasses on Microhardness of Dentin

Introduction: The use of bioactive glasses to re-establish or increase mechanical properties of the root dentin may be an interesting alternative. The aim of this study was to evaluate the effect of root repair materials and bioactive glasses on the microhardness of human root dentin. Methods and Materials: Sixty-four sectioned palatal roots of human molars were prepared and two slices were obtained of the middle third of each root (one corresponding to the control group, without treatment, and the other to the experimental group). The pairs of slices were randomly divided into four groups (n=16). The root canal of experimental slices were filled with one of the following materials: mineral trioxide aggregate (Angelus MTA, Angelus, Londrina, Paraná, Brazil), EndoSequence Root Repair Material (ERRM, Brassler, Savannah, GA, USA), Bioglass (45S5) and an experimental niobophosphate glass (NbG). The specimens were stored in an oven at 37ºC, in an environment with 100% humidity for 60 days. The specimens were subjected to a microhardness test. Four indentations were made at a distance of 20 µm from the root canal lumen. For microhardness analysis, comparing the experimental groups and their respective controls, the Student’s-t test was applied. For comparison of the percentage increase in microhardness between the groups, the data were statistically analyzed by using One-way ANOVA and Tukey’s test. The level of significance was set at 0.05. Results: All the materials significantly increased the dentin microhardness values (P<0.05). MTA showed a higher increase in microhardness (94.8±42.7%), similar to that of EndoSequence (62.3±39.9%). The 45S5 (46.5±30.0%) and NbG (53.8±31.3%) showed the lowest percentages of increase in microhardness, but were statistically similar to those of EndoSequence. Conclusion: All the materials tested were capable of increasing root dentin microhardness.Keywords: Bioactive Glass 45S5; Dental Materials; Hardness Test; Microhardness Tests; Root Canal Filling Material

POSSIBILIDADES TERAPÊUTICAS NO TRATAMENTO DE DENTES JOVENS PORTADORES DE POLPA VIVA: uma revisão da literatura

A abordagem tradicional da dentina em cáries profundas, não raro resulta em exposição da polpa, o que coloca em risco sua vitalidade e exige medidas de tratamento mais invasivas. Uma vez determinada a condição de vitalidade do dente, a terapia pulpar em dentes jovens com polpa normal ou pulpite reversível pode ser realizada através de técnicas mais conservadoras, visando à manutenção da vitalidade do dente. A modalidade de tratamento a ser implementada deve variar em decorrência da idade do paciente, do fator etiológico, do diagnóstico pulpar e do estágio de formação radicular do dente. Assim, este estudo tem como objetivo apresentar as alternativas terapêuticas e os materiais utilizados no tratamento da polpa de dentes jovens, visando a manutenção da vitalidade pulpar.Descritores: Cárie; Diagnóstico; Endodontia.Abstract: The traditional approach of dentin deep caries often results in exposition of the pulp, thus putting at risk its vitality and requiring more invasive treatments. Once determined the tooth vitality, the pulp therapy in young teeth with normal pulp or reversible pulpitis can be accomplished by more conservative techniques, aiming at the maintenance of the tooth vitality. The modality of treatment to be implemented should vary due to the patient’s age, etiology, diagnosis and root formation stage. Thus, this study aims to present the therapeutic alternatives and the materials used in the pulp treatment of young teeth, in order to maintain pulp vitality.Descriptors: Caries; Diagnosis; Endodontics

Antimicrobial action of ozonated water and photodynamic therapy with sonic activation in root canals infected with Enterococcus faecalis

New protocols are constantly being tested in the search for complete disinfection of root canals without the undesirable effects of sodium hypochlorite. This study evaluated the antimicrobial effect of ozonated water and photodynamic therapy (PDT) with s

Micro Push-out Bond Strength and Bioactivity Analysis of a Bioceramic Root Canal Sealer

Introduction: Bioactive endodontic sealers have been developed to improve the quality of root canal obturation. EndoSequence Bioceramic (BC) Sealer is amongst calcium silicate-based materials recently developed for permanent root canal filling. The objective of this study was to evaluate the bioactivity of BC Sealer and its micro push-out bond strength to dentin compared to AH-Plus (AH) sealer. Methods and Materials: To perform the micro push-out test, 24 root canals of mandibular premolars were instrumented and divided into two groups (n=12). Each root was cut into 4 slices and lumens of the canals were filled with the sealers and submitted to micro push-out test. Failure mode was assessed using scanning electron microscopy (SEM). Bioactivity of BC sealer was investigated with scanning electron microscopy/energy-dispersive X-ray (SEM/EDS) and X-ray diffraction (XRD). Bioactivity assessments were reported descriptively. Bond strength data were analyzed by parametric t-test (α=5%). Results: In micro push-out test AH had higher bond strength mean values (16.29 MPa) than BC sealer (9.48 MPa) (P<0.05). Both groups had low amount of adhesive failure. SEM showed the presence of a mineral precipitate after 30 days and EDS analysis showed that those precipitates have high proportion of Ca. XRD showed peaks of crystalline phases of calcium carbonate compatible with the bioactivity. Conclusion: BC sealer showed indications of bioactivity and lower bond strength to dentine compared to AH.Keywords: Bioactivity; Bioceramic; Dentine; Micro Push-Out Bond Strength; Root Canal Seale

Spontaneous Bisphosphonate-related Osteonecrosis Associated with a Tooth that Had a Necrotic Pulp: A Case Report

This study reports the endodontic treatment performed in a patient who presented with spontaneous bone exposure in the mandible while using intravenous bisphosphonate medication (ZometaÒ, Novartis Pharmaceuticals Co., Basel, Switzerland). A 63-year-old female patient was referred to a private dental clinic at Fortaleza, Brazil. The patient reported that one year before, she had undergone chemotherapy for the treatment of lung cancer and associated bone metastasis. Among the medications administered was the zolendronic acid, with dosage of 4 mg every 21 days. In the oral exam, the presence of extensive bone exposure was observed in the lingual region near tooth 37. The patient reported severe pain on palpation in the region; in the pulpal sensitivity test with cold stimulus, there was an absence of pain, characteristic of pulp necrosis. Radiographically, no periapical lesion was observed. Thus, endodontic treatment was performed, and instrumentation with Reciproc R25 files in the mesial root canals and R40 in the distal canal was done, alongside with abundant 2.5% sodium hypochlorite irrigation. Interappointment medication with calcium hydroxide was maintained for 15 days. In the second session, there was the spontaneous detachment of the exposed cortical bone fragment. The root canals were filled with gutta-percha and Endosequence BC Sealer cement. After two years, complete tissue repair was observed, and the patient presented with normal periapical tissues and the tooth in masticatory function.   It may be concluded that a possible relationship between pulp and periapical infections and osteonecrosis exists in patients who use bisphosphonates

Effect of Anatomical Customization of the Fiber Post on the Bond Strength of a Self-Adhesive Resin Cement

Aim. The aim of the study was to evaluate, by means of the push-out test, the effect of the anatomical customization of the fiber post on the bond strength of a self-adhesive resin cement. Methods. Twelve endodontically treated, human, upper central incisors were randomly divided into two groups (n=6): control (glass fiber posts cemented with Relyx® U200) and customized (glass fiber posts anatomically customized with translucent composite resin cemented with Relyx U200). The roots were sectioned into three slices, cervical, middle, and apical, and photographed with a digital camera attached to a stereomicroscopic loupe. The images were analyzed by software, for evaluation of the cement line. The slices were subsequently submitted to the push-out test until the post had completely extruded, and the fracture mode was analyzed with a stereomicroscopic loupe. Results. The results showed significant differences between the groups in the different root thirds in relation to the area occupied by air bubbles (p<0.05). Bond strength, when all the thirds are considered, was 8.77 ± 4.89 MPa for the control group and 16.96 ± 4.85 MPa for the customized group. Conclusion. The customized group showed greater bond resistance than the control group and a more uniform cement layer

Development and Characterization of Experimental ZnO Cement Containing Niobophosphate Bioactive Glass as Filling Temporary Material

AIMS: The aim of this study was to develop and characterize a temporary restorative material based on a zinc oxide matrix containing niobophosphate bioactive glass (NbG) for the caries-affected dentin treatment. MATERIAL AND METHODS: NbG was added to a ZnO(2) matrix in different concentrations (wt%). EDS-SEM, ATR-FTIR and XRD analyses were performed to characterize the cement. Calcium release was evaluated in TRIS solution after 1, 7 and 14 days by colorimetric method (A(650)). Compressive strengths and setting times were performed to analyze mechanical properties. RESULTS: EDS spectra confirmed the presence of Ca, P and Nb in the groups containing NbG. EDS mapping exhibit the ZnO(2) homogeneous distribution, and NbG immersed in this matrix. Peaks suggesting interaction between matrix and NbG were not detected in Ftir spectra. Calcium releasing showed to be time-dependent for experimental groups containing 10, 20, 30 and 40%. The NbG incorporation progressively increased the compressive strength values in the experimental groups. NbG incorporation seemed to influence the ZnO(2) matrix early setting reaction. No statistical difference was observed in the final setting time. CONCLUSION: The addition of NbG particles into zinc oxide matrix could work as a mechanical reinforcement. It is suggested that the calcium released by the cement containing at least 10% NbG could induce apatite formation

Influence of calcium hydroxide in the bond strength of root canal sealers to dentin: push-out testing

Avaliou-se a influência do uso do hidróxido de cálcio como medicação intracanal na resistência de união de obturações endodônticas à dentina radicular quando realizadas com o cimento AH Plus ou Epiphany. Raízes palatinas de primeiros molares superiores humanos foram preparadas com sistema rotatório EndoSequence, e divididas em 4 grupos: G1 fatias preenchidas com AH Plus; G2 - fatias preenchidas com Epiphany; G3 - dentes que receberam medicação intracanal com hidróxido de cálcio por 14 dias e posterior preenchimento das fatias com AH Plus; G4 - dentes que receberam medicação intracanal com hidróxido de cálcio por 14 dias e posterior preenchimento das fatias com Epiphany. Para o teste de pushout as raízes foram fixadas, cortadas e delas obtidas secções seriadas das regiões cervical, média e apical. Após a manobra de preenchimento das fatias, essas permaneceram armazenados por 7 dias em câmara a vácuo a 37º C sob condições de umidade ambiental. Decorrido esse período, os dentes foram preparados para o ensaio mecânico. Os corpos-de-prova foram adaptados a um suporte fixado à base da máquina de ensaios mecânicos universal, onde aplicou-se uma carga à velocidade de 0,5 mm/min no sentido ápico-cervical até o completo deslocamento do material obturador. Após a realização dos ensaios, foi feita análise do padrão de fraturas dos corpos de prova utilizando a microscopia eletrônica de varredura. A análise de variância revelou diferença estatisticamente significante entre os grupos (p<0,05). O teste de Tukey identificou que a resistência de união obtida pelos grupos Epiphany e Epiphany + hidróxido de cálcio foi estatisticamente menor do que a dos grupos AH Plus e AH Plus + hidróxido de cálcio; e, a comparação entre grupos mostrou que o grupo AH Plus + hidróxido de cálcio mostrou-se estatisticamente superior ao grupo AH Plus, portanto o hidróxido de cálcio influencia positivamente apenas na adesão do cimento AH Plus.We evaluated the influence of calcium hydroxide as an intracanal dressing in the bond strength of root canal filling to the root dentin when performed with AH Plus sealer or Epiphany. Palatal roots of maxillary first molars were prepared with rotary system EndoSequence and divided into 4 groups: G1 - slices filled with AH-Plus G2 - slices filled with Epiphany, G3 - teeth that received root canal dressing with calcium hydroxide for 14 days and then filling out the slices with AH-Plus; G4 - teeth that received root canal dressing with calcium hydroxide for 14 days and then filling out the slices with Epiphany. To test push-out the roots were fixed, cut them and obtained serial sections of cervical, middle and apical. After the maneuvers fills the slices, they remain stored for 7 days in a vacuum chamber at 37°C under conditions of environmental humidity. After this period the teeth were prepared for mechanical testing. The samples were adapted to a bracket attached to the base of the testing machine universal where we apply a load at a speed of 0.5 mm/min towards apicocervical to the complete displacement of the filling material. After the testing, analysis was made of the pattern of fractures of the specimens using scanning electron microscopy. Analysis of variance revealed a statistically significant difference between groups (p < 0,05). The Tukey test indicated that the bond strength obtained by the groups Epiphany and Epiphany + Calcium hydroxide was lower than that of groups AH Plus and AH-Plus + Calcium hydroxide; and, the comparison between groups showed that group AH-Plus + Calcium hydroxide was statistically higher than the AH-Plus group, so the Calcium hydroxide has a positive effect only in the adhesion of AH-Plus sealer

Effect of the addition of the niobophosphate bioactive glass in the gutta-percha: Development, characterization, bond strength to dentin and influence on biofilm formation

Os objetivos deste estudo foram desenvolver e caracterizar um compósito para obturação endodôntica à base de guta-percha e vidro niobofosfato. Foi avaliado a resistência de união à dentina radicular do compósito experimental, da guta EndoSequence BC, ambos sem o uso de cimento além do cimento AH Plus associado a guta-percha através do ensaio de push-out. A análise dos padrões de fratura foi realizada com auxílio de MEV. Análises usando EDX and MEV-EDS foram realizadas para verificar a composição e distribuição das partículas de vidro na superfície e no interior da matriz de guta-percha dos materiais testados. Os resultados foram analisados estatisticamente pelos testes ANOVA e Tukey, sendo considerado significante quando p 0,05). GBC group had the lowest bond strength average (1,34 MPa), which was a statistically significant difference compared to the other groups (p < 0,05). Groups GBC, GNB and VNB presented the lowest total biovolume values in 30 days. The highest viable biovolume values in 30 days of incubation, in decreasing order, were as follows: HA; PTP and OBT; GBC and VNB and finally GNB. As regards live percentage, the experimental material GNB presented the lowest values at 3 and 30 days, while VNB presented the lowest value at 14 days, with statistically significant difference in comparison with the other groups (P < 0,05). The experimental material GNB presented the highest pH value after 30 days of immersion in PBS, and greatest Zn release in all the time intervals analyzed when compared with the other groups; and the greatest Ca release at 14 and 30 days, similar to Group GBC, which released a larger quantity of Si when compared with the other groups in the time intervals of 14 and 30 days. The experimental root filling composite (GNB) showed an ability to adhere to root dentine equal to the current gold standard root filling with gutta-percha and sealer (Ah Plus) and was able to inhibit the formation of microbial biofilm when compared to HA and conventional gutta-percha