Browsing by Author "Bottino, Marco Antonio"
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Item Comparison of resin push-out strength to root dentin of bovine- and human-teeth.(2009-07) Galhano, Graziela; de Melo, Renata Marques; Valandro, Luiz Felipe; Bottino, Marco AntonioAim : To compare the push-out strength of bovine- and human-root dentin and, thus, evaluate the suitability of bovine-root dentin to substitute human-root dentin for bond strength testing. Materials and Methods : Ten single-rooted human-teeth and ten bovine incisors were prepared using a #3 bur of a fiber post system (12 mm long). The posts were duplicated with resin cement (Duolink). The root canals were treated with All Bond 2 adhesive system and the resin posts were cemented using Duolink. The specimens were cut perpendicular to their long axis, yielding disc-specimens with 1.5 mm thickness, which were submitted to a push-out test (1 mm/min). Ten bond strength values per group (n = 10) were used for statistical analysis (Student t test, a =.05). Results : Statistically significant differences were found for the bond strength values between bovine- (4.1 ± 1.3 MPa) and human-root dentin (8.6 ± 5.7 MPa) (P =.0001). Conclusion : The push-out strengths of bovine- and human-root dentin were statistically different.Item Fracture resistance of bovine incisors restored with different glass fiber posts: Effect of the diameter of fiber post.(2012-09) Zogheib, Lucas Villaça; Vasconcellos, Luis Gustavo Oliveira; Salvia, Ana Carolina Rodrigues Danzi; Balducci, Ivan; Pagani, Clovis; Bottino, Marco Antonio; Valandro, Luiz FelipeAim: Compare the effect of three post designs on the fracture resistance and failure modes of composite core - fiber post - crownless tooth sets. Materials and Methods: Ninety bovine incisors were selected and divided into nine groups of 10 specimens. The teeth were assigned to three groups based on the post design: Cylindrical, tapered, and double-tapered. Each group was subdivided into three subgroups in accordance with the diameter of the post: Small (No.1), medium (No.2), and large (No.3). The Panavia F system was used for post cementation. The specimens were mounted in acrylic resin blocks with a layer of silicone rubber covering the roots. A universal testing machine compressively loaded the specimens from the palatal side at a crosshead speed of 1 mm/min and at an angle of 135Ί to the long axis of the teeth, until failure occurred. The failure mode was determined by a stereomicroscope inspection of all the specimens. Data were analyzed by one-way ANOVA and the Tukey test (P < 0.05). Results: The fracture resistance was affected by the type of post (P < 0.0001). A narrower diameter for all of the post systems allowed for higher resistance. The main failure mode in the large cylindrical group was catastrophic fractures, while the main failures in the other eight groups were favorable. Conclusion: Narrower diameter posts showed higher fracture resistance. The dominant failure pattern was repairable fracture, except for those with large cylindrical groups.Item Marginal and internal discrepancies of zirconia copings: Effects of milling system and finish line design.(2015-01) Ribeiro, Isabella Lima Arrais; Campos, Fernanda; Sousa, Rafael Santiago; Alves, Maria Luiza Lima; Rodrigues, Dalton Matos; Souza, Rodrigo Othavio Assunção; Bottino, Marco AntonioContext: Discrepancies at the abutment/crown interface can affect the longevity of zirconia restorations. Aim: The aim was to evaluate the marginal and internal discrepancies (MD and ID) of zirconia copings manufactured by two milling systems with different finish lines. Materials and Methods: Three aluminum‑master‑dies (h = 5.5 mm; Ø =7.5 mm; 6°), with different finish lines (large chamfer [LC]; tilted chamfer [TC]; rounded shoulder [RS]) were fabricated. Twenty impressions were made from each master die and poured. Sixty zirconia copings were manufactured and divided according to the factors “finish line” and “milling system” (n = 10): CADLC = Computer‑aided design/computer‑aided manufacturing (CAD/ CAM) + LC; CADTC = CAD/CAM + TC; CADRS = CAD/CAM + RS; MADLC = manually aided design/manually aided manufacturing (MAD/MAM) + LC; MADTC = MAD/MAM + TC; and MADRS = MAD/MAM + RS. For MD analysis, each coping was fixed, and the distance between the external edges of the coping and the edge of the cervical preparation was measured (50 points). Using the same copings, the ID of each coping was evaluated, by the replica technique, at 12 points equally distributed among the regions (n = 10): Ray (R), axial (A), and occlusal (Occl). The measurements were performed by optical microscopy (×250). The data (μm) were subjected to parametric and non‑parametric statistical analyses. Results: For the MAD/MAM system, the “finish line” (P = 0.0001) affected significantly the MD median values (μm): LC = 251.80a, RS = 68.40a and TC = 8.10b (Dunn’s test). For the CAD/CAM system, the median MD values (μm) were not affected by the factor “finish line” (P = 0.4037): LC = 0.82a, RS = 0.52a, and TC = 0.89a. For the ID, it was observed interaction between the finish line types and the region (P = 0.0001) and between region and milling system (P = 0.0031) (RM‑ANOVA). Conclusions: The CAD/CAM system presented lower MD values, regardless the finish line. However, the MAD/MAM system showed ID values smaller than those of CAD/CAM.