Discussion
swelling, Pain, aggressiveness, pain, ’ pain, orthodontic
STILL
The application of platelet rich fibrin to facilitate orthodontic tooth movement has not been thoroughly investigated regarding its effect on patients’ daily activities. To the best of our knowledge, there were no previous studies that evaluated patients’ perceptions associated with i-PRF injection during orthodontic treatment. Hence, in this study we assessed pain, discomfort, swelling, and difficulty in mastication and swallowing as well as limitation in jaw movement after application of i-PRF during retraction of the upper canines. Moreover, we evaluated patients’ satisfaction with the procedure. We used VAS to measure the variables that are subjective in nature because it is a very reliable and easy method in addition to its wide usage in other previous studies [The low-speed centrifugation protocol (700 rpm within 3 min) was adopted to obtain the i-PRF [PRF is the second generation of platelet concentrates that has the advantage of gradual release of growth factors that last up to 28 days [Patients’ responses regarding pain, discomfort, swelling, and difficulty in mastication and swallowing as well as limitation in jaw movement after the second injection were used for analysis because we wanted patients to have prior experience with injection. In this way, we wanted to reduce the role of stress during the response, especially immediately after the injection. By analysing the responses after the second injection, we obtained more reliable information about how patients felt. Additionally, none of the participants used any kind of analgesics what ensured the reliability of the answers.Despite the differences between the experimental and control sides in the perception of injection-related “stress” for most variables and at most assessment timepoints, the mean values of the studied variables were relatively low even 1 h after injection (T1). For example, our data demonstrated that the levels of pain on the experimental side were statistically significantly higher than on the control one at T1, T2, T3 (Our results agreed with the findings of the study by Liou [Pain levels accompanied by PRP injection have been studied by El Gazzar et al. [In our study, the intensity of pain and discomfort observed at T1 were similar to values detected by Kuroda et al. who registered the highest level of pain and discomfort after one hour of the mini-screw placement [Swelling levels were greater on the experimental side within the first six hours (Our findings regarding swallowing and jaw movement limitations demonstrated that there were no statistically significant increases at all time intervals (Satisfaction rates were recorded after the second injection as the patient had a complete perception of the injection procedures and was accustomed to the presence of the coil springs. Fairly good incidence of satisfaction has been reported (75.7%) amongst participants, and this can be attributed to the little-invasive approach which resembles the infiltrative nature of the anaesthesia and is of limited aggressiveness. Eighty-one percent of the patients admitted that extraction of the premolars was more annoying than the injection itself. Our findings were in line with Ganzer et al.’s study who stated that patients’ pain perception after premolar extraction was more negative when compared to the application of miniscrews [The split-mouth design and not having placebo injections might be considered as the main limitations of this study that could somehow confound our findings. Still, that placebo option would have been unethical and would have caused possible unjustifiable pain from a therapeutic point of view, had it been applied, and hence it was abandoned. Long-term effects of the injection on patients’ perceptions could be addressed when having prolonged follow-up periods, however, all values dropped down to zero at the fifth evaluation time point. Apparently, blinding was only ensured when analysing the results because it was not possible to be employed whether to the main investigator who conducted the research or to the patients who received the injections.