*2.1. Study Population*

Five subsequent, healthy patients (3 males and 2 females), with a partially edentulous posterior maxilla with vertical dimensions of less than 8 mm but preferably more than 4 mm, requiring dental implants for dental rehabilitation, were included in this study and underwent a unilateral MSFE procedure 6 months before the dental implants were placed. The average age was 61 years (range: 51–70).

The study was performed in accordance with the principles of the Declaration of Helsinki. Since the study involved a Conformité Européenne (CE)-marked device (biphasic calcium phosphate) being used for its intended purpose (use as carrier material for bone augmentation in sinus floor elevation procedures) and the harvested material is regarded as surgical waste, no specific regulatory approval from a medical ethical committee was required. Patients provided written consent before the study-related MSFE and dental implant procedures were undertaken. Biopsies were retrieved during dental implant surgery, with trephine drills, implicating the tissue in the hollow drill is considered surgical waste and no extra inconvenience to the patient.

## *2.2. Maxillary Sinus Floor Elevation Procedure*

A unilateral two-stage MSFE was performed as described by Tatum [2] and similar to the previously reported 6-month and 9–12-month studies with pure BCP [12,46]. MSFE surgery was performed under local anesthesia. All patients took amoxicillin 500 mg orally, 4 times daily during 7 days, starting one day preoperatively. Oral hygiene was performed with 0.12% chlorhexidine-digluconate 3 times daily for two weeks. The autogenous bone graft was harvested from the maxillary tuberosity at the implant site with mallet and chisel and grinded in small pieces. Before filling the created area at the sinus bottom, the bone graft was mixed in equal proportions with BCP granules (60% HA and 40% β–TCP, Straumann® Bone Ceramic, Straumann Holding AG, Basel, Switzerland). No collagen membrane was placed to cover the lateral window [48] (Figure 1A–E).
