ABSTRACT
BACKGROUND: Zirconia all-ceramic restorations have been widely used in the repair of various complicated dental or dentition defects. Considering its surface chemical inertness, zirconia bonding is extremely crucial for the clinical practice of zirconia all-ceramic restorations. Currently, there are a variety of clinically selectable bonding materials and surface treatments for dental restorations. OBJECTIVE: To study the effects of different surface treatments and binders on the bonding performance of zirconia. METHODS: Zirconia tiles with different diameters were made and randomly divided into 16 groups (n=30 per group). Super-Bond C & B, polycarboxylic acid zinc binder, Panavia F resin cements and Fuji I of glass ionomer cements were selected. The surface of zirconia was treated by four different methods, including grinding, sand blasting, silane treatment and sand blasting plus silane treatment. Zirconia tiles were bonded by different binders, placed into static distilled at 37 ℃ for 24 hours, and then the shear bond strength was detected using a universal testing machine. RESULTS AND CONCLUSION: (1) With the use of the same binder, four surface treatments showed different effects on the bonding strength (P < 0.05), and the strongest bonding strength appeared after sandblasting plus silane treatment on the zirconia surface. (2) With the use of the same surface treatment, different binders showed different effects on the bonding strength (P < 0.05). Super-Bond C & B binder exhibited the best bonding effect, followed by Panavia F resin cements and Fuji I of glass ionomer cements, and polycarboxylic acid zinc binder showed the worst bonding effect. To conclude, these four surface treatments can all enhance the bonding strength to a certain extent, and Super-Bond C & B binder with sandblasting and silane treatment can achieve the highest bonding strength on the zirconia surface.
ABSTRACT
<p><b>OBJECTIVE</b>Striatum may be involved in depressive disorders according to the neuroimaging analysis and clinical data. However, no animal model at present supported the possible role of striatum in the pathogenesis of depression. In the present study, we have investigated the depressive-like behavior in mice recently intoxicated with 3-nitropropionic acid (3-NP), a widely known toxin that selectively damages the striatum in the brain.</p><p><b>METHODS</b>Mouse model was made with subacute systemic 3-NP treatment, and the depressive-like behavior was measured using the duration of immobility during forced swimming test (FST).</p><p><b>RESULTS</b>When the mice at day 15 post-intoxication just totally recovered from motor deficits, the duration of immobility in FST was significantly longer than that in controls. The depressive-like behavior was not due to the fatigue or general sickness following 3-NP intoxication and could be reversed by the antidepressant, desipramine hydrochloride. In two successive FST in 24 h interval, the depressive-like behavior could be observed again in subsequent FST (at day 16 post-intoxication), and the mice presented a normal "learned helplessness".</p><p><b>CONCLUSION</b>A novel depression animal model could be established in mice during the initial period of recovery from 3-NP intoxication. The depression-like behavior might occur independently without involvement of cognitive defects, and the striatal lesions may underlie the depression-like behavior attributable to 3-NP intoxication.</p>