Comparative Evaluation of the Apical Leakage of Different Bioceramic Retrofilling Materials with and without Smear Layer: A Stereomicroscopic Study

Objective: Present in?vitro study aimed to evaluate the apical leakage of different bioceramic retrofilling materials with and without smear layer. Materials and Methods: Sixty human single?rooted teeth were decoronated at a standardized root length of 13 mm, chemo?mechanically prepared and obturated. After obturation, root?end resection was done and root?end cavities were prepared using ultrasonic tips. The specimens with prepared retro cavities were randomly assigned into 2 groups (n = 30) based on the smear layer removal protocol used. Each group was further subdivided into 3 subgroups (n = 10) based on the bioceramic retrofilling material MTA (Mineral Trioxide Aggregate; Proroot Dentsply/Tulsa), CEM (Calcium?Enriched Mixture; Bionique Dent, Tehran) and ERRM (EndoSequence® Root Repair Material; Brasseler USA, Savannah, GA). The extension of dye (2% Rhodamine B) penetration was measured in millimetre using a stereomicroscope at 10× zoom. Results were statistically analysed using one?way ANOVA (analysis of variance) test and unpaired Student’s t test. Results: In the presence of smear layer, MTA demonstrated maximum mean apical leakage value (1.70 ± 0.30), followed by CEM (1.40 ± 0.37) and ERRM (1.40 ± 0.23), which was statistically not significant. Without the smear layer, ERRM demonstrated the least mean apical leakage value, which was statistically significant as compared with CEM (P <.05) and MTA ( P <.01). Conclusion(s): All bioceramic retrofilling materials demonstrated apical leakage irrespective of the presence or absence of the smear layer. The presence of a smear layer is beneficial for the sealing ab

Influence of Powder-to-Gel Ratio on Physicochemical Properties of a Calcium Silicate Sealer / Influencia de la relación polvo-gel sobre las propiedades fisicoquímicas de un sellador de silicato de calcio

Abstract Differences in liquid-to-powder ratio can affect the properties of calcium silicate-based materials. This study assessed the influence of powder-to-gel ratio on physicochemical properties of NeoMTA Plus. Setting time (minutes), flow (mm and mm²), pH (at different periods), radiopacity (mm Al) and solubility (% mass loss) were evaluated using the consistencies for root repair material (NMTAP-RP; 3 scoops of powder to 2 drops of gel) and root canal sealer (NMTAP-SE; 3 scoops of powder to 3 drops of gel), in comparison to Biodentine cement (BIO) and TotalFill BC sealer (TFBC). Statistical analysis was performed using one-way ANOVA and Tukey tests (α=0.05). BIO had the shortest setting time, followed by NMTAP-RP and NMTAP-SE. TFBC showed the highest setting time and radiopacity. BIO, NMTAP-RP, and NMTAP-SE had similar radiopacity. All materials promoted an alkaline pH. NMTAP-RP/SE presented lower solubility than BIO and TFBC. Regarding the flow, TFBC had the highest values, followed by NMTAP-SE, and NMTAP-RP. BIO had the lowest flow. In conclusion, NMTAP in both powder-to-gel ratios showed high pH and low solubility. The increase in the powder ratio decreased the setting time and flow. These findings are important regarding the proper consistency and work time to clinical application.

Resumen Las diferencias en la proporción líquido/polvo pueden afectar las propiedades de los materiales a base de silicato de calcio. Este estudio evaluó la influencia de la proporción polvo/gel en las propiedades fisicoquímicas del cemento NeoMTA Plus. El tiempo de fraguado (minutos), la fluidez (mm y mm²), el pH (en diferentes períodos), la radiopacidad (mmAl) y la solubilidad (% de pérdida de masa) fueron evaluados utilizando las consistencias para el material de reparación radicular (NMTAP-RP; 3 cucharadas de polvo/2 gotas de gel) y para cemento sellador del conducto radicular (NMTAP-SE; 3 cucharadas de polvo/3 gotas de gel), en comparación con el cemento Biodentine (BIO) y el cemento TotalFill BC (TFBC). El análisis estadístico se realizó utilizando las pruebas ANOVA y Tukey unidireccionales (α=0.05). BIO tuvo el tiempo de fraguado más corto, seguido de NMTAP-RP y NMTAP-SE. TFBC mostró el mayor tiempo de fraguado y radiopacidad. BIO, NMTAP-RP y NMTAP-SE tuvieron una radiopacidad similar. Todos los materiales promovieron un pH alcalino. NMTAP-RP/ SE tuvieron una solubilidad menor que BIO y TFBC. Con respecto a la fluidez, TFBC tuvo los valores más altos, seguido de NMTAP-SE y NMTAP-RP. BIO tuvo la fluidez más baja. En conclusión, NMTAP en la relación polvo/gel mostró un pH alto y una baja solubilidad. El aumento en la proporción de polvo disminuyó el tiempo de fraguado y la fluidez. Estos hallazgos son importantes con respecto a su consistencia y tiempo de trabajo durante la aplicación clínica.

Research hotspots and progress of bone repair materials in tissue engineering / 中国组织工程研究

BACKGROUND: With the improvement in medical level, the clinical demand for bone repair materials is gradually Increasing, and the requirements are also getting more and more. OBJECTIVE: To review the related research progress In the field of bone repair materials In recent years, to analyze the advantages and disadvantages of different materials, and to guide future development In this research field. METHODS: A computer-based online search of CNKI, Wanfang, PubMed, Web of Science databases was performed to retrieve papers published during 1950-2019 with the search terms “tissue engineering, bone repair material, bone defect, natural bone material, bone graft replacement material, traditional Chinese medicine” in Chinese and English. A total of over 900 papers were retrieved, and 68 of them were included In the final analysis. RESULTS AND CONCLUSION: In recent year, with the flourish development of bone tissue engineering, the research of bone tissue repair materials is in the ascendant. In addition to optimizing natural bone, a variety of bone graft substitute materials have been developed, for example, natural macromolecule materials, synthetic macromolecule materials, biomedical ceramics materials, biomedical metal materials, etc., but these materials have different properties. Although there are many bone repair materials at present, the Ideal bone repair materials are few. Therefore, bone tissue repair and bone remodeling is still one of the urgent orthopedic problems to be solved In the clinic. In addition, the traditional Chinese medicine for bone repair, such as pyritum combined with modern bone repair materials, can effectively avoid some of the drawbacks of the current bone repair materials, thereby effectively treating bone defect diseases. This deserves In-depth investigation In the field of bone repair.

Basic principles and repair material selection of abdominal wall defect after breast reconstruction for breast cancer surgery / 中国实用外科杂志

Autologous breast reconstruction after radical resection of breast cancer has been widely used in clinic.Some surgical methods of autologous breast reconstruction may cause abdominal wall defect to a certain extent.The abdominal wall defect leads to the loss of normal function,which leads to a series of serious pathophysiological changes.At present,transverse rectus abdominis myocutaneous flap(TRAM) and deep inferior epigastric artery perforator flap(DIEP) are commonly used for breast reconstruction.According to the different types of abdominal wall defect after breast autoreconstruction for breast cancer surgery,the corresponding surgical repair scheme should be formulated on the basis of strictly following the basic principles of abdominal wall repair.At the same time,appropriate materials for repairing abdominal wall defect are selected according to the different extent of abdominal wall defect.The posterior sheath and peritoneum of rectus abdominis are usually intact after breast reconstruction,and the anterior sheath of rectus abdominis may be retained.The different layers of abdominal wall can be repaired by surgical methods,and the application of repair materials is emphasized.

Preparation technology of oyster hydroxyapatite porous material for bone repair / 国际生物医学工程杂志

Objective To verify the feasibility of applying hydrothermal synthesis for preparing oyster hydroxyapatite(HA) and to develop a preparation method of oyster HA porous material for bone repair.Methods Hydrothermal synthesis was applied for preparing oyster HA,and the reaction condition was 220 ℃ for 6 h.Then,the prepared oyster HA was used as the raw material for porous scaffold preparation by sponge-soaking and sintering,successively.The porosity and compressive strength of the scaffold were adjusted by controlling the soaking time and absorbed HA slurry of the sponges.Results Hydrothermal synthesis was an effective method for preparing oyster HA.When the volume of the sponge cube was 1 cm3,the material absorbed by one to three times sponge-soaking were 0.184 8 g,0.318 1 g and 0.426 1 g,respectively,the corresponding porosity were 91.5％,82.9％ and 78.5％,and the compressive strength were 1.06 MPa,3.99 MPa and 8.49 MPa.Conclusion The oyster shell powder can be effectively converted into HA under the hydrothermal reaction condition of 220 ℃ for 6 h.The preparation of HA porous bone repair material by sponge-soaking method can obtain ideal porosity and mechanical strength.However,in this preparation process,the number of sponge-soaking and the weight of the absorbed HA slurry should be exactly controlled in order to obtain desired properties.

In Vitro Cytotoxicity Evaluation of Three Root-End Filling Materials in Human Periodontal Ligament Fibroblasts

Abstract The aim of this study was to evaluate in vitro the cytotoxicity on human periodontal ligament fibroblasts of three root-end filling materials: MTA Angelus(r), EndoSequence Root Repair Material Putty(r) and Super EBA(r). A primary culture of human periodontal ligament fibroblasts was previously obtained in order to evaluate the cytotoxicity of the three extracts from the root-end filling materials after 2 and 7 days of setting. Serial dilutions of these extracts (1:1, 1:2, 1:4 and 1:8) were evaluated at 1, 3 and 7 days using the methyl-thiazol-tetrazolium (MTT) colorimetric assay. Cell viability was evaluated as percentage of the negative control group, which represented 100% cell viability. Statistical analyses were done with t-test, ANOVA and Kruskal-Wallis test at a significance level of 5%. It was found that the main difference among root-end filling materials was in the higher dilutions (p<0.05), but there was a similar behavior in lower dilutions (p>0.05). Cell viability of MTA Angelus(r) was superior for 2-day setting (p<0.05), compared with the other two root-end fillings. There were no statistically significant differences between 7-day set MTA Angelus(r) and EndoSequence Root Repair Material Putty(r). Super EBA(r) showed the lowest percentage of cell viability at higher dilutions (p<0.05). Therefore, MTA Angelus(r) and EndoSequence Root Repair Material Putty(r) were less cytotoxic in the highest dilution (1:1) compared with Super EBA(r).

Resumo O objetivo deste trabalho foi avaliar in vitro a citotoxicidade em fibroblastos do ligamento periodontal humano de três cimentos de retrobturação: MTA Angelus(r), EndoSequence Root Repair Material Putty(r) e Super EBA(r). Uma cultura de fibroblastos primários do ligamento periodontal humano foi obtida anteriormente a fim de avaliar a citotoxicidade dos três extratos dos cimentos de retrobturação após 2 e 7 dias de endurecimento. As diluições em série destes extratos (1:1, 1:2, 1:4 e 1:8) foram avaliados em 1, 3 e 7 dias empregando o ensaio colorimétrico metil-tiazol-tetrazólio (MTT). A viabilidade celular foi calculada em base da porcentagem do grupo de controle negativo, que representou 100% de viabilidade de células. As análises estatísticas foram realizadas com o teste t, ANOVA e teste de Kruskal-Wallis a um nível de significância de 5%. Verificou-se que a principal diferença entre os cimentos de retrobturação estava nas diluições mais elevadas (p<0,05) e houve um comportamento semelhante nas diluições mais baixas (p>0,05). A viabilidade celular dos fibroblastos do ligamento periodontal humano foi superior para MTA Angelus(r) de 2 dias de endurecimento (p<0,05), em comparação com os outros materiais de retrobturação. Não houve diferença significante entre MTA Angelus(r) e EndoSequence Root Repair Material Putty(r) de 7 dias de endurecimento. Super EBA(r) mostrou a menor percentagem da viabilidade celular nas diluições mais altas (p<0,05). Portanto, os cimentos de retrobturação MTA Angelus(r) e EndoSequence Root Repair Material Putty(r) foram menos citotóxicos na diluição mais alta (1:1) em comparação com Super EBA(r).

Result of using a biologic collagen implant (Permacol) for mesenteric defect repair after excision of a huge mesenteric lymphangioma in a child

Mesenteric lymphangiomas, which involve near total mesentery, are extremely rare. A mesenteric lymphangioma should be treated through excision because they can cause invasion of vital structures, bleeding, or infection. After excision of a huge mesenteric lymphangioma, internal herniation may occur through a large mesenteric defect leading to intestinal volvulus, obstruction, and other life-threatening circumstances. We report a case in which a biologic collagen implant (Permacol) was used for mesenteric defect repair after excision of a huge mesenteric lymphangioma. The implant did not cause any symptoms or complications during follow-up for 4 years. When encountering large defects of mesentery, closure with implant can be a feasible choice, and Permacol could be a possible implant for closing the defect.

Biomechanical study on repair materials of unilateral maxilla defect based on finite element model / 医用生物力学

Objective To study the biomechanical effect from different prosthetic materials used on unilateral maxillary defect repair by three dimensional finite element (FE) analysis method. Methods The maxillary unilateral defect model was reconstructed by medical image processing software MIMICS. The prosthesis was generated by mirroring technology. After processing, the FE unilateral maxillary defect model and healthy maxillary model were established to simulate stress distributions on the maxilla during occlusion. Results The maximum stress on maxilla using different repair materials was always found concentrated on the edge of maxilla connected with zygoma (the positions attaching zygolabialis and levator anguli oris). The minimum stress of from the maxilla edge on the repair side was 8.471 MPa by using tricalcium phosphate (TCP) composite. The maximum stress from the maxilla edge on the repair side was 17.55 MPa by using hydroxyapatite (HA) material. Conclusions Different repair materials had no significant effect on natural side of the maxilla after restoration, while a greater impact of force status on the repair side was found. The elastic modulus of different repair materials can be used as a basis for maxilla restoration in clinic.