APCs in sinus floor augmentation

Abstract

After tooth loss in the posterior area of the maxilla, sinus floor elevation is often required to compensate the vertical bone loss due to sinus pneumatization. This narrative review reports on the potential benefits of autologous platelet concentrates (APCs) during this procedure. As for transcrestal approach, APCs have been used as "sole" substitute/graft. However, because of the low number of clinical trials available with PRGF, and even none for PRP, no definitive conclusions can be made regarding their efficacy. The number of studies on the use of L-PRF were outnumbered indicating good feasibility for vertical bone gain, with a high implant survival rate and a low degree of complications. PRP and PRGF have not been studied as a "single/sole" substitute for a one-stage lateral window approach, probably because of the weak physical characteristics of the membranes. L-PRF alone appears to be a predictable grafting material for lateral maxillary sinus grafting and a reduced RBH should not be considered as a risk factor. Compared to a "standard" bone substitute L-PRF shows slightly less vertical bone gain (consider enough membrane application and use of bony window as new sinus floor roof over the implant apices), enhanced early resorption (first 6 months after application), but a similar stable bone gain afterward. For a two-stage lateral window approach, APCs "alone" cannot be recommended, due to their weak withstand to the sinus pneumatization forces. APCs combined with bone substitutes seem to accelerate bone formation, without any additional benefits on the long-term new bone gain. The use of L-PRF membranes for the treatment of perforations appears to be an effective treatment option, but further clinical studies are needed to confirm this. Even though the abovementioned statements are based on large numbers of studies, additional RCTs comparing APCs with different types of grafting procedures for sinus elevation are needed.

Keywords: Schneiderian membrane; autogenous platelet concentrates; lateral window technique; membrane perforation; sinus floor augmentation; sinus grafting; sinus lift; transcrestal technique.

FIGURE 1

CBCT images (A, B): M‐D; (C, D): B‐P section, (A, C) immediately after transcrestal sinus floor elevation using L‐PRF as sole substitute; (B, D) after 4 months of healing Intra‐oral long‐cone radiographs; (E): at the day of surgery; (F): 4 years later.

FIGURE 2

CBCT images of a 1‐stage lateral window approach using L‐PRF as sole substitute (A): pre‐op situation, (B): immediate post‐op, (C): 4 months' implant uncovering before loading, and (D): 2 years post loading; notice the increase in bone density over time.

FIGURE 3

Detailed view of bone regeneration after one‐stage lateral window approach using L‐PRF as sole substitute. The bone density is similar for the pre‐op native bone (A) and the regenerated bone 2 years post loading (B).

FIGURE 4

Closure of a sinus membrane perforation via a double layer of L‐PRF membranes (face towards the perforation). The Schneiderian membrane moved again up and down when the patient was breathing.

FIGURE 5

Coverage of the access window to the maxillary sinus with a double layer L‐PRF membrane (face towards the window).