## 4 Results
When comparing pain levels during the treatment with an FA, a similar level was found for both age groups (NRS = 4.5 in adolescents and 4.0 in adults) (Figure 6b). Graphical visualizations of the comparisons are presented in Figure 6a,b. Further analysis of pain revealed that merely 18 persons (18.95% of total group) considered pain during SRME as the main disadvantage. In the above group, the percentage of adolescent patients was 27.27% compared to 11.76% of adults; the difference was statistically insignificant (\(p\) = 0.054). The highest value of pain, equaling 10 in the NRS, was reported by two adolescent patients: an 11y-6m-old boy and a 13y-10m-old girl. In the whole study group, no statistically significant difference in pain level was found between the sexes in relation to Haas-type SRME or FA procedures. However, when comparisons of pain/sex sensitivity during the SRME procedure were made separately for adolescents and adults, it showed that adolescent females felt the highest pain level (NRS = 6) among the four age and sex subgroups. Adult females reported a significantly higher mean pain level (NRS = 4.0) than adult males (NRS = 2.0) (\(p\) = 0.007). Additionally, the difference between adolescent females and adult males was highly statistically significant (\(p\) = 0.002) (Figure 7a-c). Figure 5: Cephalograms before and after nonsurgical treatment of the oldest male (Class III patient with appearance of diastema during SRME with Haas-type acrylic expander). Figure 6: (**a**) Pain levels during SRME according to age. (**b**) Pain levels during the treatment with lower FA according to age. Figure 7: _Cont._  
A similar comparison of pain levels according to age and sex is presented for the FA treatment (Figure 8a,b). Comparisons of pain level during FA therapy related to age and sex in the whole study group revealed no statistically significant differences in pain level reported by adolescents (NRS = 4.5) vs. adults (NRS = 4.0), as well as females (NRS = 5.0) vs. males (NRS = 4.0). However, when the comparison of pain or sex sensitivity during FA therapy was conducted separately for adolescents and for adults, adolescent females felt insignificantly higher pain (NRS = 5.0) than adolescent males (NRS = 4.0), whereas adults females reported significantly higher mean pain (NRS = 5.0) than males (NRS = 2.5) (\(p\) = 0.003). Interestingly, for adolescents during the period of peak pubertal growth (CS3-4), both treatment modalities were less painful in comparison to pre- and postpubertal stages, as presented in Figure 9a,b. Figure 7: (a) SRME—Pain levels in adolescent group according to sex. (b) SRME—Pain levels in adult group according to sex. (c) SRME—Pain levels according to sex—a comparison between adolescent females and adult males. Figure 8: (**a**) FA—Pain level in adolescent group according to sex. (**b**) FA—Pain level in adult group according to sex. Figure 9: _Cont._  
When examining other adverse effects, no significant differences were observed in the occurrence of pressure sores or speaking difficulties between the two age groups, indicating that these complications are similarly experienced across age demographics. Specifically, speaking difficulties were reported by a substantial portion of the overall cohort (50.53%), suggesting that the Haas-type acrylic bonded appliance commonly impacts speech, regardless of the patient's age. Headaches were only reported by two adults: an 18-year-old female and a 21-year-old male with severe skeletal maxillary deficiency (Figure 10a,b).