Purpose: This in-vitro study measured push-out bond strength of different posts as function of radicular regions.
Statement of Problem: n non-circular or excessively flared root canals, prefabricated posts may not fit well, increasing cement thickness and bubbles at coronal level which may alter its mechanical performance causing impaired post retention. Push-out bond strength test in different radicular thirds of posts will detect location of failure in bonded esthetic posts.
Methods: 40 sound extracted human central incisors were used in this study. All teeth were endodontically treated and decoronated 2 mm above CEJ. Then were randomly divided into 4 groups of 10 each regarding type of post used: group 1 (PD): Polymer infiltrated ceramic, Paradigm MZ 100 (3M-ESPE); group 2 (FRC) Fiber post, Postec Plus (Ivoclar Vivadent); group 3 (ZR): Lava Zirconium dioxide blocks (3M-ESPE); group 4 (CP): Cosmo Post, Zirconium dioxide (Ivoclar Vivadent). All posts were luted with Panavia 21 (Kuraray Noritake, Japan). Push-out tests were performed to evaluate the bond strength of different posts at different radicular regions. Data were statistically analyzed using one way (ANOVA)and Scheffe test made pairwise comparison (α = 0.05).
Results: FRC group recorded the highest mean bond strength value (11.78 ± 0.79MPa). PD group showed higher results (10.10 ± 1.12MPa) than ZR (9.56 ± 0.85 MPa) and CP (7.93 ± 0.89 MPa) and the 2 latter groups were not significantly different from each other p ≤ 0.05. Regardless to post type, it was found that middle region recorded highest bond strength means value, then apical region, meanwhile the lowest mean bond strength values were recorded at cervical regions p ≤ 0.05.
Conclusions: Within limitations of this study the following can be drawn: 1- Push-out mean bond strength of different esthetic posts are significantly affected by the type of its materials and manufacturing; FRC recorded the highest bond strength values, ZR and CP showed the least values (P ≤ 0.05). 2- Regardless type of the post, the middle radicular region (as Fiber Reinforced Composite) recorded the highest bond strength then the apical region, meanwhile the cervical region (as Cosmo Post) showed the lowest bond strength values P ≤ 0.05.
Keywords: Push-Out Bond Strength; Esthetic Post

Background: This case reports were described extra-wide diastemas closing technique using different type of restorative materials. A female and a male patients presented with wide diastema in the anterior region and both of them demanded esthetic natural looking smile. It was decided to apply zirconia ceramics for female patient and porcelain fused to laser sintered metal restorations for male patient, according to their financial situations.
Case Reports: After evaluating the diagnostic models obtained from both patients, a knife-edge step preparation was performed in case porcelain fused to metal restorations, and subgingival 1 mm champher preparation was performed in case zirconia ceramic restorations. In order to achieve esthetics, the teeth in the anterior region were prepared as far as possible from the buccal region and parallelism was maintained between the abutments without any root canal treatment. In both patients, adjustment of gingival level was perform to ensure smile design. The polycarboxylate cement was used as permanent cementation procedure after the control session at third week.
Conclusions: As a result of weekly follow ups at 1^st, 3^rd, 6^th weeks and 9 months, no biological or mechanical complications were observed. The wide diastemas were closed and patients were satisfied with the good esthetic results. Patient was kept on recall every 6 months. There is no need to make root canal treatment to bring the teeth into the desired position in the wide diastema cases all the time. It is possible to prevent the health of the teeth following controlled tooth preparation.
Keywords: Diastema Closure; Esthetic Dentistry; Wide Diastema; No Root Canal Treatment