Limitations
orthodontic
PLAQUE
There was a higher proportion of female participants in the control group (65%) compared to the intervention group (50%). As previously stated, female patients have been shown to have lower levels of plaque and have a greater level of knowledge of oral health (In terms of outcome measures, although the descriptors for scoring OMPI aim to be as objective as possible; it can be challenging to determine the subtle differences between whether a surface should be scored between a 1 and a 2 or a 2 and a 3. If a systematic error did indeed exist in the recording of the OMPI, this will likely have been applied to participants in both the intervention and control group. Therefore, it is unlikely to have affected the trial outcome.Another issue with the OMPI is whether it is a valid surrogate measure for plaque control. It could be argued that the OMPI in this trial only represents the quality of plaque control before an orthodontic examination. The Hawthorne effect has also been shown to reduce tooth surface area covered with plaque in orthodontic patients (Like GI, photographs to assess the intra-rater reliability of the IBI were not feasible. However, the intra-rater reliability of this index has been found to be in the range of 91.3%–93.1% (