The primary reason was to confirm the efficacy of the dye to stain only contaminated surfaces, and, secondly, to assess the sterility of brand new burs. We found that only one unsterilized brand-new bur in the negative control group showed contamination that can be due to handling error.
Manual cleaning, is simple and cost-effective but can potentially serve as a source of contamination due to the aerosols produced during the process.12,13 Manual scrubbing also produce unpredictable results, as it is very operator-sensitive.6 In our study, 77.14% dental burs in Group-1 demonstrated contamination.
Ultrasonic cleaning has been found to be effective in removing saliva and dried blood from the dental instruments and increases safety of dental personnel during handling of instruments.24 In the present study, 82.85% burs in Group-2 showed contamination.
Enzymatic agents help to digest organic debris, including bacteria due to presence of amylases, lipases and proteases, but their use is operator-dependent and if manufacturer's guidelines are not exactly followed regarding dilution of enzyme solution, its immersion time, reuse of solution greatly affects the cleaning efficacy and might lead to recontamination of dental instruments.6 In the present study, the burs in group-3 were treated with a combination of manual cleaning followed by immersion in the enzyme solution.
The burs in the test group-4 were subjected to a combination of pre-cleaning methods (manual + ultrasonic + enzyme) and yet 68% diamond dental burs exhibited contamination.
Our results suggest that current methods of pre-cleaning of dental burs might be insufficient to ensure complete cleaning of contaminants.
- Mean numbers of propagules from 30,000 burs and legumes fed passed per steer during each of four 24-h periods postfeeding for the propagule-type by sampling-period interaction, and totals Period after feeding (h) Type 0-24 24-48 48-72 72-96 Total (propagules) Burs 153 Aa(a) 483 Aa 272 Aa 89 Aa 998 a Caryopses 148 Aa 492 Aa 337 Aa 138 Aa 1114 a Legumes 2830 Bb 5220 Cb 977 Aa 199 Aa 9226 b a Means within rows followed by the same uppercase letter, and means within columns followed by the same lowercase letter, are not significantly different at the 0.05 level as determined by paired comparisons Both sets of results are reasonable given the methodologies of the respective studies.
Most of the burs in our study were destroyed during passage, and relatively few intact caryopses survived passage.
If most burs and caryopses are destroyed when consumed by cattle on forage diets, this would initially appear to argue against buffalograss fitting the FF hypothesis, specifically expected trait 7: "Seeds are sufficiently small, tough, hard, and inconspicuous enough to escape the molar mill and spitting response of a large mammal," (Janzen, 1984).
Percentage germination of burs was negligible in all experiments, but percentage germination of caryopses was significantly higher than for burs recovered from the feces at some time periods (Table 3).
It should be noted, however, that the burs were kept in the germination chamber after the 28-day run.
Mean time to complete germination was not different for burs and caryopses in the control treatment, but was considerably less (P [less than] 0.05) for caryopses than for burs in all fed treatments (Table 4).