Results: A significant difference (p < 0.001) of mean debonding force was found between different types of teeth in vivo. Clinically, ARI scores were not significantly different (p = 0.921) between different groups, but overall higher scores were predominant.
Conclusion: Bracket debonding force should be measured on the same tooth from the same arch as the significant difference of mean debonding force exists between similar teeth of the upper and lower arches. The insignificant bracket failure pattern with higher ARI scores confirms less enamel damage irrespective of tooth types.
METHODS: Sixty-five cylindrical block of Fuji IX Fast were prepared using split moulds. The demineralizing solution was an acetate buffered demineralizing solution at pH 403. The remineralizing solution was a buffered solution containing 1.5 mM Ca, 0.9 mM P and 10 ppm F at pH 7. The blocks of Fuji IX Fast were subjected either to two-day alternating cycles of remineralization and demineralization for up to 24 days (test); 6 two-day cycles of demineralizing or remineralizing solution separately, or deionized distilled water alone (controls) or were left untreated (base line control). Mineral profiles of Ca, P, Sr and F within 100 microm of the material surface were assessed following 8, 16 and 24 days of treatment (test); 4, 8 or 12 days (controls) or for baseline control samples, using electron probe microanalysis (EPMA).
RESULTS: There were significant changes in mineral profile in the test specimens in terms of Sr and Ca concentrations. A molecule for molecule exchange of these elements resulted between GIC and eluant solutions. Fluoride loss from the GIC occurredto the level comparable with uptake levels recorded in eluant solutions from previous studies. The ionic exchanges appeared to be the result of dissolution followed by an equilibrium-driven diffusion. These exchanges were superficial though substantial.
CONCLUSIONS: Simulated exposure of Fuji IX to the oral environment resulted in an exchange of Ca from the bathing solutions into Fuji IX to replace any Sr which was lost to the GIC. Fluorine loss from the GIC followed previously described patterns. The possible clinical significance of this exchange was discussed.
METHODS: Different volume percentages of HEMA were tested in four experimental silane-based primer solutions (additions of HEMA: 0, 5.0 vol%, 25.0 vol% and 50.0 vol%). An experimental silane blend (primer) of 1.0 vol% 3-isocyanatopropyltrimethoxysilane (ICMS) + 0.5% bis-1,2-(triethoxysilyl) ethane (BTSE) was prepared and used. The experimental primers together with the control group were applied onto acid-etched premolars for attachment of orthodontic brackets. After artificial aging by thermocycling the shear-bond strength was measured. The fractured surfaces of all specimens were examined under scanning electron microscopy (SEM) to evaluate the failure mode on the enamel surface.
RESULTS: The experimental primers showed the highest shear-bond strength of 21.15 MPa (SD ± 2.70 MPa) and with 25 vol% showed a highly significant increase (P < 0.05) in bond strength. The SEM images showed full penetration of adhesive agents when using silane-based primers. In addition, the SEM images suggested that the predominant failure type was not necessarily the same as for the failure propagation.
CONCLUSIONS: This preliminary study suggested that nonacidic silane-based primers with HEMA addition might be an alternative to for use as adhesion promoting primers.
METHODS: Six master dies were duplicated from the prepared maxillary first premolar tooth using nonprecious metal alloy (Wiron 99). Thirty copings (Procera AllCeram) of 0.6-mm thickness were manufactured. Three types of luting media were used: zinc phosphate cement (Elite), glass ionomer cement (Fuji I), and dual-cured composite resin cement (Panavia F). Ten copings were cemented with each type. Two master dies were used for each group, and each of them was used to lute five copings. All groups were cemented according to manufacturer's instructions and received a static load of 5 kg during cementation. After 24 hours of distilled water storage at 37 degrees C, the copings were vertically compressed using a universal testing machine at a crosshead speed of 1 mm/min.
RESULTS: ANOVA revealed significant differences in the load at fracture among the three groups (p < 0.001). The fracture strength results showed that the mean fracture strength of zinc phosphate cement (Elite), glass ionomer cement (Fuji I), and resin luting cement (Panavia F) were 1091.9 N, 784.8 N, and 1953.5 N, respectively.
CONCLUSION: Different luting agents have an influence on the fracture resistance of Procera AllCeram copings.
MATERIALS AND METHODS: A questionnaire consisting of 35 questions was distributed by mail or an online survey to 425 registered dentists selected according to place of work by stratified random sampling.
RESULTS: One hundred fifty-three dentists responded to the survey. A positive attitude towards FS and PRR was noted among most Malaysian dentists. About half of the respondents used FS/PRR occasionally (48.4%), while few (13.7%) applied them routinely. The majority of the dentists agreed that minimally invasive dentistry is important and FS are effective in caries prevention, using them on high caries-risk individuals. Most of the dentists used pumice or paste to clean teeth before placing FS/PRR. A significant number of dentists used a bonding agent prior to placing FS. Although only 57.5% dentists were aware of guidelines for FS use, most dentists agreed that guidelines are important.
CONCLUSION: Although there was a positive attitude towards FS/PRR, few dentists applied them routinely. Some of the steps undertaken for placement of FS and PRR were outdated. Updating local guidelines for dentists to ensure uniform practice of FS and PRR is justified.