Discussion
gingivitis, tooth floss
PERIODONTITIS, GINGIVITIS, PLAQUE

The instruction to brush to the best of one’s abilities led to an increased effort in the BP group. Their brushing time exceeded that of the AU group by nearly one minute (see Fig. 
At this point, the question arises whether the increased effort shown by the BP group in terms of extended brushing time and an increased likelihood of interdental cleaning had a substantial impact on brushing success. The data are discouraging in this respect and are not in support of the research Hypothesis b). Overall plaque levels assessed immediately after brushing did not show significant group differences. Specifically, regarding the gingival margins, group differences were small. Furthermore, the more frequent use of interdental devices in the BP group did not improve their cleanliness in the proximal sections of the gum lines. Instead, plaque persisted in 80% of these sections. The toothbrush type used in this study has a crisscross design of the bristles and has been proven to be superior in its efficacy compared to other toothbrushes [
Improving one’s oral cleanliness thus requires more than an increase in brushing time and the application of tooth floss. However, people appear to have only these aspects in mind when they try to optimize their brushing behavior. In terms of dentistry, this appears to be a dysfunctional concept since it does not lead to better oral cleanliness. However, people themselves might consider it functional in that they believe that these behavioral changes would make a difference. This is exactly what the data show. The BP group rated their effectiveness even higher than the AU group. This supports research Hypothesis c). From their perspective, there appears to be no need for further changes, especially since they overestimate their oral hygiene in general. While objective plaque data indicate that less than 40% of the sections of the gingival margins were free from plaque, participants in the BP group thought it was 70%. Interestingly, both groups seem to be aware that they brush their inner surfaces less clean than their outer surfaces. Nevertheless, the BP group did not ameliorate the behavioral neglect of these surfaces in comparison to the AU group. This could indicate that during brushing, they have aspects such as time and interdental cleaning in mind rather than the oral cleanliness that they should achieve.
The current data may contribute to a better understanding of the apparent contradiction between the widespread implementation of oral hygiene as a daily routine and its low effectiveness in preventing gingivitis and periodontitis. Asking people to perform oral hygiene to the best of their abilities is a standard procedure to assess oral hygiene skills [
The current research has certain strengths. It is a randomized controlled study, which allows for firm causal inferences. It confirms the results of an earlier less controlled quasiexperimental study regarding differences in brushing behavior with respect to the instruction to brush as usual and to brush to the best of one’s abilities [