RESUMEN
Hyaluronic acid filler injections are regarded as the gold standard procedure for facial rejuvenation. Standing as the second most injected cosmetic filler, calcium hydroxyapatite-based fillers are also widely used worldwide. However, to our knowledge, prospective studies assessing patient satisfaction and sonographic changes in dermal thickness after a single session of a hybrid filler combining hyaluronic acid and calcium hydroxyapatite have not been previously published. Methods: This was a single-center, prospective, quasi-experimental study comprising 15 participants between 32 and 63 years of age. Each participant received a single-session treatment based on facial subcutaneous injections of HArmonyCa, a hybrid combination filler comprising hyaluronic acid and calcium hydroxyapatite. This study involved an intrapatient control design and a 120-day follow-up with clinical and sonographic assessment. For this purpose, standardized photographic images, high-frequency ultrasound evaluations, and physician- and patient-oriented overall aesthetic improvement scores were recorded at 0, 30, 90, and 120 following the procedure. Results: According to our findings, 20% of the subjects had an exceptional improvement; 20%, "very improved"; and 60%, "improved." Intrapatient sonographic comparison showed a significant increase in dermal thickness, at 90 and 120 days, only on the side treated (P < 0.001). Conclusion: In our clinical study, a single-session treatment with a hybrid product combining hyaluronic acid and calcium hydroxyapatite resulted in positive cosmetic satisfaction and increased dermal thickness.