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OBJECTIVE: To evaluate the microshear bond strength (µSBS) of self-adhesive resin (SA) cement on leucite-reinforced glass-ceramic using silane or universal adhesive. MATERIALS AND METHODS: Ceramic blocks were etched with 9.5% hydrofluoric acid and divided into three groups (n = 16): (1) negative control (NC) without treatment; (2) Single Bond Universal (SBU); (3) RelyX Ceramic Primer as positive control (PC). RelyX Unicem resin cement was light-cured, and µSBS was evaluated with/without thermocycling. The µSBS was analyzed using one-way analysis of variance. The fractured surfaces were examined using stereomicroscopy and scanning electron microscopy (SEM). RESULTS: Without thermocycling, µSBS was highest for PC (30.50 MPa ± 3.40), followed by SBU (27.33 MPa ± 2.81) and NC (20.18 MPa ± 2.01) (P < 0.05). Thermocycling significantly reduced µSBS in SBU (22.49 MPa ± 4.11) (P < 0.05), but not in NC (20.68 MPa ± 4.60) and PC (28.77 MPa ± 3.52) (P > 0.05). PC and NC predominantly fractured by cohesive failure within the ceramic and mixed failure, respectively. CONCLUSION: SBU treatment improves µSBS between SA cement and glass ceramics, but to a lower value than PC, and the improvement is eradicated by thermocycling. NC exhibited the lowest µSBS, which remained unchanged after thermocycling.

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BACKGROUND: This study aimed to investigate the microshear bond strength of universal bonding adhesives to leucite-reinforced glass-ceramic. METHODS: Leucite-reinforced glass-ceramic blocks were polished and etched with 9.5% hydrofluoric acid for 1 min. The specimens were assigned to one of four groups based on their surface conditioning (n = 16): 1) NC: negative control with no further treatment; 2) SBU: Single Bond Universal (3M ESPE); 3) ABU: ALL-BOND Universal (Bisco); and 4) PC: RelyX Ceramic Primer and Adper Scotchbond Multi-Purpose Adhesive (3M ESPE) as a positive control. RelyX Ultimate resin cement (3M ESPE) was placed on the pretreated ceramic and was light cured. Eight specimens from each group were stored in water for 24 h, and the remaining eight specimens were thermocycled 10,000 times prior to microshear bond strength evaluation. The fractured surfaces were examined by stereomicroscopy and scanning electron microscopy (SEM). RESULTS: After water storage and thermocycling, the microshear bond strength values decreased in the order of PC > SBU and ABU > NC (P < 0.05). Thermocycling significantly reduced the microshear bond strength, regardless of the surface conditioning used (P < 0.05). Cohesive failure in the ceramic and mixed failure in the ceramic and resin cement were observed in the fractured specimens. The percentage of specimens with cohesive failure after 24 h of water storage was: NC (50%), SBU (75%), ABU (75%), and PC (87%). After thermocycling, the percentage of cohesive failure in NC decreased to 25%; however, yet the percentages of the other groups remained the same. CONCLUSIONS: Although the bond strength between resin and hydrofluoric acid-etched glass ceramic was improved when universal adhesives were used, conventional surface conditioning using a separate silane and adhesive is preferable to a simplified procedure that uses only a universal adhesive for cementation of leucite-reinforced glass-ceramic.

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Neuroendocrine neoplasm of the larynx is a morphologically heterogeneous group of tumors. This unusual neoplasm includes the four different type of tumors. Paraganglioma is the best-known neural origin tumor. The epithelial origin tumor is further divided based on the degree of differentiation into well, moderately, and poorly differentiated carcinoma. The diverse biological behavior of neuroendocrine neoplasm of larynx makes an accurate diagnosis of paramount importance, since treatment depends on diagnostic accuracy. The diagnosis is based primarily on light microscopy, and immunohistochemical and/or ultrastructural investigations are needed to diagnose correctly. The mainstay of treatment of moderately differentiated neuroendocrine carcinoma of the larynx is surgery. Elective neck treatment should be performed considering the high likelihood of cervical lymph node metastases. The 5-yr survival rate approximates 50%, and 10-yr survival rate is only 30%.