Orthodontic bracket bonding to glazed full-contour zirconia

OBJECTIVES: This study evaluated the effects of different surface conditioning methods on the bond strength of orthodontic brackets to glazed full-zirconia surfaces. MATERIALS AND METHODS: Glazed zirconia (except for the control, Zirkonzahn Prettau) disc surfaces were pre-treated: PO (control), polishing; BR, bur roughening; PP, cleaning with a prophy cup and pumice; HF, hydrofluoric acid etching; AA, air abrasion with aluminum oxide; CJ, CoJet-Sand. The surfaces were examined using profilometry, scanning electron microscopy, and electron dispersive spectroscopy. A zirconia primer (Z-Prime Plus, Z) or a silane primer (Monobond-S, S) was then applied to the surfaces, yielding 7 groups (PO-Z, BR-Z, PP-S, HF-S, AA-S, AA-Z, and CJ-S). Metal bracket-bonded specimens were stored in water for 24 hr at 37℃, and thermocycled for 1,000 cycles. Their bond strengths were measured using the wire loop method (n = 10). RESULTS: Except for BR, the surface pre-treatments failed to expose the zirconia substructure. A significant difference in bond strengths was found between AA-Z (4.60 ± 1.08 MPa) and all other groups (13.38 ± 2.57 - 15.78 ± 2.39 MPa, p < 0.05). For AA-Z, most of the adhesive remained on the bracket. CONCLUSIONS: For bracket bonding to glazed zirconia, a simple application of silane to the cleaned surface is recommended. A zirconia primer should be used only when the zirconia substructure is definitely exposed.

Clinical Study of Deep Neck Infection: Clinical Analysis of a Hundred Cases / 대한이비인후과학회지

BACKGROUND: Due to the antibiotic therapy and the appropriate treatment, the incidence of the infections of the neck decreased. But during last 5 years in the Red Cross hospital, there were the hundred cases. And a few significant complications were still experienced. OBJECTIVES: For the early treatment and the prevention of the infection of the neck, it is necessary to study the characteristics, the diagnosis, and the treatment. MATERIALS AND METHODS: The hundred cases of the infections of the neck in the Red Cross hospital from January in 1992 to December in 1996 were analyzed about the age and sex distribution related to spaces involved, the location of cellulitis and abscess, the side of lesion, the symptoms and signs, the etiologic events, the associated conditions, the results of culture, the special diagnostic methods, the treatments, and the complications. RESULTS: In the infections of the neck, the following contents were more frequent: male(sex), the third decade(age), pain and fever(symptoms and signs), acute tonsillitis and odontogenic origin(etiologic events), Diabetes Mellitus(associated condition), hemolytic Streptococcus and Bacteroides(the results of culture), and Computerized Tomography(the special diagnostic methods). There was no significant difference in the side of lesion. The useful treatment in the peritonsillar space infection was the incision and drainage and then tonsillectomy two or three weeks after the recovery of the infection, and in the deep neck space infection, only antibiotic therapy or the incision and drainage with the antibiotic therapy were useful. The complications were four cases with two cases of sepsis, one cases of mediastinitis, and one cases of internal jugular vein thrombosis. CONCLUSION: In spite of the antibiotic therapy and the appropriate treatment, there were some complications experieced. So, we must know the characteristics of the infection of the neck well, and the systemic and active attitude is necessary.