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The aim of this study was to evaluate, in vitro, frictional forces produced by ceramic brackets and arch wires of different alloys. Frictional tests were performed on three ceramic brackets: monocrystalline (Inspire ICE), polycrystalline (InVu), polycrystalline with metal slot (Clarity), and one stainless steel bracket (Dyna-Lock). Thirty brackets of each were tested, all with .022" slots, in combination with stainless steel and nickel-titanium wires .019" × .025", at 0° and 10° angulation, in artificial saliva. Arch wires were pulled through the slots at a crosshead speed of 10 mm/min. There were statistically significant differences between the groups of brackets and wires studied (p < .05). The polycrystalline brackets with metal slots had values similar to those of conventional polycrystalline brackets, and the monocrystalline brackets had the highest frictional forces. The nickel-titanium wires produced the lowest friction. The addition of metal slots in the polycrystalline brackets did not significantly decrease frictional values. Nickel-titanium wires produced lower friction than those of stainless steel.

Chlorhexidine reduces the TS counts in TTBPE, but has no effect on biofilm mass.

OBJECTIVE: To evaluate qualitative and quantitative changes in the saliva of individuals undergoing orthodontic treatment with fixed appliances. METHODS: Salivary samples were collected from 50 individuals divided in two groups: Experimental Group - patients with fixed orthodontic appliances (n=25); and Control Group - subjects with no orthodontic appliances (n=25). Salivary flow rate, pH, buffering capacity, amylase activity, concentrations of total proteins, calcium and glucose were measured in all salivary samples. RESULTS: There was a reduction in salivary pH and buffering capacity and an increase in the concentration of calcium ions in the experimental group (p<0.05); there was also an increase in glucose, amylase and protein concentrations in the saliva of the Experimental Group, but the differences were insignificant. There was insignificant correlation between calcium ion concentration and salivary flow or between buffering capacity and salivary flow. CONCLUSION: The saliva of individuals with fixed orthodontic appliances had lower pH, buffering capacity and calcium concentration than that of individuals without any type of orthodontic appliance. These oral changes are enough to cause tooth demineralization. Patients with orthodontic appliances should adopt additional oral hygiene procedures

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Objective: To test the null hypothesis that metal and ceramic brackets have no effect on the epithelial cells of the buccal mucosa. Materials and Methods: Two metal and two ceramic brackets were bonded in 21 individuals of both sexes. With the use of liquid-based exfoliative cytology, morphometric and morphologic changes in buccal mucosa cells adjacent to these brackets were determined and were compared at three time points: baseline (T0), 60 days after placement (T1), and 30 days after removal of the brackets (T2). Results: A decrease in nuclear area and an increase in cytoplasmic area occurred in the buccal mucosa cells adjacent to the brackets at T1 (P Ͻ .01). At T2, this altered morphometry persisted only in cells adjacent to the metal brackets, although to a lesser degree than at T1 (P Ͻ .01). A greater decrease in nuclear area was noted in cells adjacent to the metal brackets than in those next to the ceramic brackets (P Ͻ .01). At T0, the proportions of surface and subsurface cells were similar, but at T1, a predominance of surface cells was observed (P Ͻ .05). At all time points, smears of cells appeared normal or normal with some inflammatory changes. Conclusion:The hypothesis is rejected. Placement of metal and ceramic brackets in the buccal cavity induces cellular alterations. These alterations do not suggest malignancy. (Angle Orthod. 2008;00:373-379.)