scholarly journals External Perforating Push Out Lateral Osteotomies for Treatment of Crooked Nose

2021 ◽  
Vol 8 (2) ◽  
pp. 20-28
Author(s):  
Sameh Amin ◽  
Tamer Fawzy ◽  
Wassim Mikhaiel ◽  
Mohamed Hosny
Keyword(s):  
Author(s):  
Luciana Bernardo Lima de Souza
Keyword(s):  

O objetivo deste estudo foi avaliar a união de um sistema adesivo, associado a uma resina composta, à superfícies dentinárias intrarradiculares irradiadas com laser Er:YAG utilizado em associação ao condicionamento ácido. Foram utilizadas raízes huma-nas obtidas a partir de pré-molares inferiores, que receberam dois tipos de tratamentos diferentes prévios à aplicação do agente adesivo e da resina composta, divididos em dois grupos: G1 (teste) – laser + ácido + adesivo e G2 (controle) – ácido + adesivo. Destes, duas amostras de cada grupo foram processadas e destinadas à avaliação em Microscopia Eletrônica de Varredura (MEV) para análise morfológica de superfície da dentina intrarradicular. Para o teste de resistência de união, as raízes dos dois grupos foram restauradas, seccionadas ao nível do terço cervical e submetidas ao teste de cisalhamento (push-out). Como resultados, após os testes mecânicos verificou-se melhor desempenho adesivo do grupo laser/ácido (G1) sendo a diferença estatisticamente significante (Teste T, Student). A análise morfológica revelou para o grupo 1, uma superfície irregular, de aparência escamosa, e com alguns túbulos dentinários obstruídos. O grupo 2 apresentou túbulos dentinários abertos e dentina intertubular sem irre-gularidades. Concluiu-se com este estudo in vitro, que a irradiação com laser de Er:YAG associada ao condicionamento ácido promove um padrão morfológico na superfície da dentina intrarradicular que pode interferir positivamente nos valores de resis-tência de união de um sistema adesivo.palavras-chaves: Laser er:yag., Adesão


Structures ◽  
2021 ◽  
Vol 31 ◽  
pp. 769-780
Author(s):  
Yong Liu ◽  
Lanhui Guo ◽  
Jun Shi ◽  
Jingfeng Wang

Buildings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 182
Author(s):  
Zhi-Qi He ◽  
Changxue Ou ◽  
Fei Tian ◽  
Zhao Liu

This paper develops a new type of shear connection for steel-concrete composite bridges using Ultra-High Performance Concrete (UHPC) as the connection grout. The UHPC-grout strip shear connection is fabricated by preforming a roughened slot in the concrete deck slab, welding an embossed steel rib longitudinally to the upper flange of the steel girder, and casting the strip void between the slot and the steel rib with UHPC grout. The structural performance of the new connection was validated by two sets of experimental tests, including push-out testing of shear connectors and static and fatigue testing of composite beams. The results of push-out testing indicate that the UHPC-grout strip shear connection exhibits a significant improvement of ductility, ultimate capacity, and fatigue performance. The interface shear strength of the UHPC-grout strip connection is beyond 15 MPa, which is about three times that of the strip connection using traditional cementitious grouts. The ultimate capacity of the connection is dominated by the interface failure between the embossed steel and the UHPC grout. The results of composite-beam testing indicate that full composite action is developed between the precast decks and the steel beams, and the composite action remained intact after testing for two million load cycles. Finally, the trail design of a prototype bridge shows that this new connection has the potential to meet the requirements for horizontal shear.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Amr M. Elnaghy ◽  
Ayman Mandorah ◽  
Ali H. Hassan ◽  
Alaa Elshazli ◽  
Shaymaa Elsaka

Abstract Background To evaluate the effect of surface treatments on the push-out bond strength of Biodentine (BD) and white mineral trioxide aggregate (WMTA) to fiber posts. Methods Two brands of fiber posts were used: Reblida post; RP and RelyX post; RX. Each type of post (n = 80/group) was divided into four groups (n = 20/group) and exposed to surface treatment as follows: Control (no treatment), sandblasting (SB), hydrofluoric acid (HF), and TiF4 4 wt/v%. Each group was further subdivided into two subgroups (n = 10/subgroup) based on the type of CSCs used as follows: Subgroup A: BD and Subgroup B: WMTA. Push-out bond strength of BD and WMTA to glass fiber posts was assessed. Data were statistically analyzed using three-way ANOVA and Tukey’s test. A Weibull analysis was performed on the push-out bond strength data. Results BD showed higher bond strength than WMTA (P < 0.001). The push-out bond strength for posts treated with TiF4 4 wt/v% showed greater bond strength than the other surface treatments (P < 0.05). The BD/RP-TiF4 4 wt/v% showed the greater characteristic bond strength (σ0) (15.93) compared with the other groups. Surface treatments modified the surface topography of glass fiber posts. Conclusions The BD/RP-TiF4 4 wt/v% showed greater bond strength compared with the other groups. The TiF4 4 wt/v% surface treatment enhanced the bond strength of BD and WMTA to glass fiber posts than the other treatments. Surface treatment of fiber post with TiF4 4 wt/v% could be used to improve the bond strength with calcium silicate-based cements.


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