Analysis of Implant Osseointegration, Bone Repair, and Sinus Mucosa Integrity Using Bio-Oss® and Hyaluronic Acid-Polynucleotide Gel (Regenfast®) in Maxillary Sinus Augmentation in Rabbits

<b>Background:</b> The combination of polynucleotides and hyaluronic acid with bovine bone grafts in maxillary sinus lift procedures appears to be a promising strategy to enhance bone regeneration. This study aimed to analyze implant osseointegration, bone repair and sinus mucosa integrity using Bio-Oss^® and Hyaluronic Acid-Polynucleotide Gel (Regenfast^®) in maxillary sinus augmentation in rabbits. <b>Methods:</b> Sinus floor elevation was performed in 12 rabbits, with one implant placed per sinus simultaneously. In the control group, sinuses were grafted with deproteinized bovine bone mineral (Bio-Oss^®) alone; in the test group, Bio-Oss^® was combined with Regenfast^®. Two histological slides were obtained per sinus after 2 weeks (six animals) and 10 weeks (six animals): one from the grafted area alone (non-implant sites), and one from the implant site. Primary outcome variables included the percentage of newly formed bone, the extent of implant osseointegration, and the number of sinus mucosa perforations caused by contact with graft granules. <b>Results:</b> After 10 weeks of healing, the test group showed a significantly higher percentage of new bone formation (37.2 ± 6.7%) compared to the control group (26.8 ± 10.0%; <i>p</i> = 0.031); osseointegration extended to the implant apex in both groups; fewer sinus mucosa perforations were observed in the test group (<i>n</i> = 5) than in the control group (<i>n</i> = 14). <b>Conclusions:</b> The addition of Regenfast^® to Bio-Oss^® granules promoted enhanced bone regeneration within the elevated sinus area and was associated with a lower incidence of sinus membrane perforations compared to the use of Bio-Oss^® alone.