Table 3.

Outcome and results of included studies concerning home oral hygiene protocols of the patients.

Author (Year)	Protocol	Outcome	Results
Azaripour et al. (2015) [22]	Use of each of the following devices 3 times a day: - Toothbrush - Dental floss - Pipe cleaner	Gingival index (GI); sulcus bleeding index (SBI); approximal plaque index (API) measured with plaque detector tablet.	SBI and GI values increased in both patients with fixed orthodontics and patients with aligners, when the initiation and course of treatment are compared. However, the growth experienced by fixed orthodontic wearers is statistically significant (SBI: p < 0.001), (GI: p = 0.001), such that it can be said that they have worse gingival conditions throughout treatment than patients with clear aligners.
Caccianiga et al. (2022) [23]	Fixed orthodontics: - Toothbrush with orthodontic head - Single-tufted toothbrush - Toothbrush Invisible orthodontics: - Soft-bristled toothbrush - Flossing Patients with pathogenic flora at T1 (protocol to be repeated 2 times daily): - Sonic toothbrush - Toothbrush - Water brush	Microbiological analysis: assessment of subgingival plaque quality by scanning electron microscopy (SEM). Differentiation into pathogenic or non-pathogenic flora.	Microbiological analysis three months after the start of treatment (T1) showed that 10 of the 25 patients with fixed appliances and 3 of the 25 with aligners had pathogenic flora. These 13 patients then adopted the modified home oral hygiene protocol, and at the next 3 months (T2) none again presented pathogenic flora on microbiological analysis of plaque samples. Analyzing the data collected at T1, it can be stated that there is a statistically significant correlation between type of orthodontics (fixed) and the presence of pathogenic bacterial flora (p < 0.05). In fact, the 10 patients with pathogenic bacteria vs. the 3 with invisible orthodontics in whom the same conditions were detected resulted in fixed orthodontics having a p-value of 0.024, which is significant.
Chhibber et al. (2017) [19]	Generic home oral hygiene instructions: - Toothpaste - Sonic toothbrush - Toothbrush - Dental floss	Plaque index (PI); Gingival index; Papillary bleeding index (PBI).	Comparison of the values obtained with PI, GI, and PBI among the three orthodontic modalities included in the study (aligners, fixed braces with self-ligating attachments, and fixed braces with elastomeric attachments) showed no statistically significant differences at follow-up after 18 months from the start of treatment (T2). In contrast, after only 9 months of treatment (T1), the GI and PBI measurements of patients with invisible orthodontics appeared significantly lower than those of the other two types of treatment. In fact, aligners resulted in 86% less chance of inducing gingival inflammation (p = 0.015) and 90% less chance of the subject having papillary bleeding (p = 0.012).
Levrini et al. (2013) [25]	Use of each of the following practices 3 times a day: - Toothbrush with orthodontic head: Bass technique for 2 min - Flossing	Plaque index; Pocket probing depth (PD); Bleeding on probing (BOP); Microbiological analysis: assessment of the presence of biofilms by real-time PCR analysis.	Patients with invisible orthodontics presented a decrease in pocket depth (p = 0.002) and a decrease in bleeding (p < 0.001) after 3 months of treatment (T2), compared with the values reported at T1 (1 month after the start of treatment). A significant correlation was revealed between fixed orthodontic treatment and increased PI (p < 0.001) and BOP (p < 0.001), as well as an inverse correlation between this therapy and patient compliance with oral hygiene (p < 0.001). A statistically significant link between type of orthodontics and increased biofilm presence was also noted (p < 0.005). Thus, it is claimed that invisible orthodontics induces less bacterial plaque accumulation when compared with treatment using fixed braces; consequently, the reduced risk of periodontal disease in patients wearing clear aligners is well established.
Levrini et al. (2015) [18]	Use of each of the following practices 3 times a day: - Toothbrush with orthodontic head: Bass technique for 2 min - Flossing	Plaque index; Pocket probing depth; Bleeding on probing; Microbiological analysis: assessment of the presence of biofilms by real-time PCR analysis.	Treatment with aligners established a statistically significant difference from fixed orthodontics with regard to all parameters analyzed (PI, PD, BOP) (p < 0.05). The amount of biofilm present was found to be significantly higher (p < 0.05) in patients wearing fixed appliances. Moreover, this amount added to all periodontal indices was shown to be worse at T2, again in individuals with fixed orthodontics, than at T0 and T1.
Sfondrini et al. (2021) [21]	3 times a day: - Electric toothbrush (2 min) 1 time a day: - Floss	Plaque index; Probing pocket depth; Bleeding on probing; Microbiological analysis: quantitative and qualitative assessment of the bacterial flora constituting the biofilm by real-time PCR analysis.	PI, PPD, and BOP values showed no significant changes in both the test and control groups. The presence of the bacterial species investigated by PCR analysis did not change statistically significantly in the distribution percentage. A significant increase (p < 0.05) was noted in the total bacterial count from T0 (14 days after professional oral hygiene) to T1 (2 months after T0), in both the test group and the control group.
Zhao et al. 2020 [20]	After each meal/snack: - Toothbrush (Bass technique) - Flossing	Plaque index; Pocket probing depth; Bleeding on probing	PI decreased statistically significantly (p < 0.05) at six months after the start of treatment. BOP and PPD did not change significantly. Brushing frequency during the day increased significantly (p < 0.05) during the course of treatment.