## 4 Discussion
The time interval between applications was 3 weeks (or until black triangles were no longer visible). The total injected dose was 0.01 cc, of which 0.25 mg was crosslinked HA. The initial mean height in mm was 1.58 \(\pm\) 0.54, while at 6 months, the mean height of the papillae was 0.70 \(\pm\) 0.29, which was a statistically significant difference with appreciable clinical effects. The positive effect of HA on interdental papilla reconstruction was also demonstrated in the study by [PERSON] and [PERSON] [11] carried out in the anterior region of the maxilla and mandible in 10 patients (two men and eight women). In total, the authors studied 35 papillae. The selected patients were classified into three groups depending on the concentration of HA being injected (1% HA in group 1, 2% HA in group 2, and 5% HA in group 3). HA was prepared by the pharmacy faculty (College of Dental Sciences, Davangere, Karnataka, India), and different HA concentrations were prepared by dissolving 10, 20, and 50 mg of powder into solution (Herb Supply, LLC, Las Vegas, NV, USA). The results demonstrated significant improvements in both the 1% and 5% groups, while paradoxically, the 2% group showed no significant improvement. The initial mean sizes of the triangles were 3.59 \(\pm\) 0.93 (group 1), 3.85 \(\pm\) 1.4 (group 2), and 3.91 \(\pm\) 1.81 in the 5% group. There were no statistically significant differences between the groups at the start of the study. Six months after injection, the average size in the 1% group was 3.43 \(\pm\) 0.85 (an increase of 0.16 mm) and 4.14 \(\pm\) 1.2 in the 2% group (a decrease of \(-\)0.29 mm). Finally, in the 5% group, the mean was 3.2 \(\pm\) 1.6, with a significant increase of 0.71 mm in the interdental papillae. It should be noted that the 5% group had a smaller relapse from the third and sixth months, unlike the 1% group, which showed signs of a relapse at 6 months. [PERSON] et al. [15] also found a positive effect of HA on papilla reconstruction in 11 patients (three men and eight women) with a total of 21 interdental papillae in the anterior maxillary region. The authors injected a total of 0.3 mL of HA gel in three injections. The result of this study was an average change of 5.04 \(\pm\) 1.5 mm in the papilla defect. At the first follow-up, 3 weeks after the first injection, there was an improvement of 0.17 \(\pm\) 0.15. In the second follow-up, 3 months later, there was an improvement with an average of 1.48 \(\pm\) 0.94. In the third follow-up, 6 months after the injection, the size of the triangle was a further improved, with an average size of 2.38 \(\pm\) 1.02. The total filling of the interdental papillae at 6 months was 2.66 mm. In short, the application of HA was successful in reconstructing the interdental papilla at 6 months. In addition, this was the only article that pointed to a significant association between age and papilla reconstruction (\(p<\) 0.01). An improvement between 58.72 \(\pm\) 20.84% was observed in patients under 40 years of age, while the percentage of change observed in subjects over 40 years of age was 34.80 \(\pm\) 9.55%; however, difference in the amount of change could possibly have been due to the small sample size and dispersion. The greatest weight in this review with the lower variability was shown by [PERSON] [16] who presented 21 (14 females, 7 males) patients and a total number of treated interdental papillary sites of 86. Overall, there was statistically significant difference in black triangle reduction between maxillary and mandibular sites at 3 and 6 months with more reduction observed in maxillary one. On the other hand, the study of [PERSON] [17] was the only one RCT that concluded the study with a comparison with physiological saline solution with no statistically significant differences. The study used a split-mouth design. The test sites were injected with 16 mg/mL HA gel (Qi Sheng Biological Agent Company Limited, Shanghai, China) at the bases of the deficient papillae. Each site received 0.05-0.1 mL of solution.