Table 2.
Main results
| Plaque Index (PI) | PI (T0) | PI (T1) | PI (T2) | T0 versus T1 | T0 versus T2 | T1 versus T2 |
|---|---|---|---|---|---|---|
| Self-ligating brackets group |
0 |
23 |
28 |
W= 153.06 P=0.001 |
W= 97.53 P=0.001 |
NS |
| Conventional brackets group |
0 |
33 |
37 ** |
W= 133.06 P=0.001 |
W= 178.0 P=0.001 |
NS |
| Control group |
0 |
14 ** |
27 |
W= 127.88 P=0.001 |
W= 188.0 P=0.001 |
NS |
| |
Buffering capacity (indicated as the more frequent nominal value for each group) |
Self-ligating group VERSUS Control group |
Conventional group VERSUS Control group |
Self-ligating group VERSUS Cnventional group |
||
| Self-ligating brackets group |
3 (middle boffering capacity) |
|
|
NS |
||
| Conventional brackets group |
4 (middle-high capacity) |
NS |
|
|
||
| Control group |
3 (middle capacity) |
|
NS |
|
||
| |
Salivary Flow (T0) |
Salivary Flow (T1) |
Salivary Flow (T2) |
T0 versus T1 |
T0 versus T2 |
T1 versus T2 |
| Self-ligating brackets group |
59 |
69 |
69 |
W= 10.7 P=0.05 |
W= 97.53 P=0.001 |
NS |
| Conventional brackets group |
51 |
59 |
59 |
NS |
NS |
NS |
| Control group |
50 |
50 ** |
50 * |
NS |
NS |
NS |
| |
% of subjects with abnormal value (>105) T0 |
% of subjects with abnormal value (>105) T1 |
% of subjects with abnormal value (>105) T2 |
T0 versus T1 |
T0 versus T2 |
T1 versus T2 |
| Self-ligating brackets group |
0% |
25% |
45% |
NS |
Chi-square= 10.17 P= 0.01 |
NS |
| Conventional brackets group |
0% |
60% ** |
20% ** |
Chi-square = 97.53 P=0.001 |
Chi-square= 24.47 P= 0.001 |
Chi-square= 88.6 P=0.001 |
| Control group |
0% |
5% |
35% |
NS |
Chi-square= 10.75 p=0.001 |
Chi-square= 14.25 P=0.01 |
| |
% of subjects with abnormal value (>105) T0 |
% of subjects with abnormal value (>105) T1 |
% of subjects with abnormal value (>105) T2 |
T0 versus T1 |
T0 versus T2 |
T1 versus T2 |
| Self-ligating brackets group |
0% |
10% |
25% |
Chi-square=5 P=0.03 |
Chi-square=4.27 P=0.04 |
Chi-square=27.22 P=0.001 |
| Conventional brackets group |
0% |
50% |
70% |
Chi-square=35.5 P=0.001 |
Chi-square=80 P=0.001 |
NS |
| Control group | 0% | 10% | 30% | NS | Chi-square=8.8 P=0.001 | Chi-square=8.8 P=0.001 |
The total PI (Plaque Index) for each group, expressed as the sum of the individual scores for each group. Significant differences among the three groups were assessed with the Friedman test for each group and the Mann-Whithney U test to assess inter-group differences and Wilcoxon signed rank test (W) for intra-group differences. Buffering capacity of saliva, expressed as the more frequent evaluation in each group, recorded before the beginning of the study. Significant differences were assessed with Chi-square test comparing five categories (low, middle-low, middle, middle-high, and high). Salivary flow expressed as the sum of the single rates for each subject. Significant differences were assessed with Friedman test and the Mann–Whitney U test and the Wilcoxon signed rank test (W) for inter-groups and intra-group differences, respectively. Prevalence of subjects with abnormal values of microbial colonization calculated as percentage respect to the numerosity of each group.