## 4 Discussion
also observed that patients with aligners described a lower level of pain in the first phases of orthodontic treatment compared to those with conventional fixed appliances. They indicated that the main cause of pain in patients with aligners was their deformation during treatment [36]. In 2018, [PERSON] also carried out a study using the VAS that analyzed the perception of pain in patients undergoing treatment with a system of passive self-ligating brackets and aligners (e.g., Invisalign) with a seven-day follow-up period. In this study, the observed statistically significant differences in pain scores between both systems, at 4 hours, 24 h, 3 days, and 7 days after starting treatment. This study described a higher level of pain in the group of patients with passive self-ligating brackets compared to the patients with aligners. It concluded, in accordance with the present study, that the level of pain had increased within the first hours after starting orthodontic treatment and was considerably reduced after seven days [35]. In 2020, a study by [PERSON] et al. evaluated pain in a sample of patients affected by fissures and craniofacial anomalies, and they analyzed the orthodontic treatments by comparing the pain scores of patients with conventional fixed appliances versus those with transparent aligners. They observed that patients undergoing treatment with fixed multibrackets appliances reported a higher level of pain and higher consumption of drugs compared to those with the transparent aligners. This study suggested that treatment with aligners may be a valuable option in patients with fissures and craniofacial anomalies due to the reduction in pain [37]. Other studies also concluded that the consumption of anti-inflammatory and/or analgesic drugs was higher in patients receiving fixed multibracket appliances compared to patients receiving clear aligners [19; 35; 37]. In the present study, both treatment groups had a similar degree of oral crowding. This may have ensured similar amounts of tooth movement in the two study groups during the follow-up period. In addition, patients in both groups received their treatments via the same experienced orthodontist; therefore, their perception of pain could not be influenced by the treatment received from an inexperienced orthodontist or by any variable related to variations between orthodontists. When assessing the influence of age on the level of pain described by patients during their orthodontic treatments, published studies indicated that there were no statistically significant differences in the level of pain when analyzing the influence of age [15; 38; 39]. In 2018, [PERSON] et al. concluded that neither the age nor the gender of patients undergoing orthodontic treatment had influenced their levels of pain, nor had it influenced their consumption of analgesic drugs [38]. A periodontal inflammatory reaction can occur during orthodontic treatment; therefore, it is necessary to use gentle and intermittent force during treatment to avoid excessive periodontal irritation to protect periodontal health. Recently, there has been a high demand for orthodontic treatment in adult patients. In these patients, there can be a high prevalence of periodontal pathology. Careful attention should be paid to patients with reduced periodontium, in whom there is a higher risk of gingival recession [40; 41]. The periodontal biotype and the health status of the periodontium may influence the level of pain described by patients during orthodontic treatment [42; 43]. According to the scientific literature, the pain described by patients during their orthodontic treatment in the first week of treatment has been extensively analyzed, but there have been few studies evaluating pain over a longer follow-up period.