Ethical Aspect and Patient Induction
The study followed the protocols of the Declaration of Helsinki and was approved by the Ethical Committee (Approval code: AUAREC20220002-11) of Al-Azhar University, Egypt. With the registration number, the current clinical trial is listed on the national clinical trial registry (ID: NCT06285903). All study participants gave informed consent after being apprised of the research methods.
A total of 20 participants were enrolled in the RCT between September 2022 and September 2023. The participants were recruited from the patient waiting list at the Periodontology Department, Faculty of Dental Medicine, Al-Azhar University (Assiut branch).
The inclusion criteria:
Patients were free from any systemic disease according to Cornell medical index(10). Patients were cooperative, motivated, and had good oral hygiene after receiving phase l therapy. The implant sites, with a residual bone height of ≤ 6 mm. The remaining natural teeth provided sufficient periodontal tissue support, and the edentulous ridges were covered with mucoperiosteum that showed no ulceration, scarring, or inflammatory symptoms. Occlusion showed sufficient intra-arch and intra-arch space for future prosthetic devices.
The exclusion criteria:
participants had no systemic illnesses that would impair the treatment results or bone quality. pregnancy, heavy smoking, active periodontal disease, and neglected oral hygiene. Uncooperative patients, patients with limited mouth-opening ability and unfavorable intermaxillary arch space, and patients with maxillary sinus disease or previous sinus surgery were also excluded.
Presurgical protocol:
Before the implant placement, every patient received thorough oral prophylaxis, including scaling and root planning (SRP), and all were informed that they must maintain meticulous oral hygiene.
Cone beam computed tomography (CBCT, Sirona, Orthophos SL3D, Dentsply, Bensheim, Germany) was utilized to estimate the height and width of the bone with the measurement of bone density (HU). Patients were then scheduled for the placement of the dental implants.
The included participants were randomized into two groups (n = 10): Group 1 comprised eight females and two males (mean age: 35.7 ± 10 years; mean residual bone height: 4.9 mm), and they were treated using the Densah drill (Versah, Jackson, MI, USA) crestal sinus lift technique. Group 2 included six males and four females (mean age: 32 ± 7.2 years; mean residual bone height: 5.4 mm), and they were treated using the piezoelectric (Satelec Acteon, Bordeaux-Merignac, Merignac, France) crestal sinus lift technique. The patients in both groups then underwent bone grafting and received the implants.
Surgical Procedures
During the surgical appointment, each patient was asked to rinse with 0.12% chlorhexidine digluconate (Orovex mouth rinse, Macro Group Pharmaceuticals, Cairo, Egypt) followed by administration of local anesthesia (Alexadricaine 1:100,000, Alexadricaine, Inc, Alexanderia, Egypt). A full-thickness flap was raised at the implant site to display the crest of the alveolar ridge. The osteotomy preparation began with a pilot drill that stopped 1 mm short of the sinus floor.
Group 1: Densah sinus lift: The implant motor was switched to reverse-densifying mode (anticlockwise, with a drill speed of 800–1500 rpm, simultaneous with copious irrigation). A 2.2 mm diameter Densah bur was used to make an advanced osteotomy with a wider Densah bur (2.5 mm and 3 mm) by varying the pressure and a pumping motion until it was 1 mm short of the sinus floor. After that, larger Densah drills (3.5 mm and 4 mm) were employed to advance past the sinus floor in increments of 1 mm (Fig. 1).
Group 2: Piezoelectric sinus lift: The osteotomy used a 2 mm twist drill to penetrate the cortical bone. Then the intra lift tips (TKW 1 to TKW 4) (Acteon, Merignac Cedex, France) were used to progressively widen the entry to the Schneiderian membrane, placing mild pressure on the tips to deepen the pathway and cooling the tips with an 80 mL/min sterile spray to minimize heat damage. The diameter of TKW 1, 2, 3, and 4 tips are 1.35 mm, 2.1 mm, 2.35 mm, and 2.8 mm, respectively. Next, a TKW 5 tip (3 mm) was inserted into the entry canal, and the ultrasonic activation was repeated for 5 s with internal irrigation at 40 mL/min, 50 mL/min, and 60 mL/min. Hydraulic pressure was utilized to push the sinus membrane upward, and then the floating of the sinus membrane was examined. Eventually, implant drills were used successively until the planned implant size was reached (3.0 mm, 3.5 mm, and 4 mm) (Fig. 2)
Following the completion of the surgical procedure for each patient, a clinical check was performed to ensure that the membrane was still intact by obstructing the patient’s nostrils and requesting that the patient blow through their nose.
Bone Graft and Implant Placement:
A xenograft was added as the grafting material (One graft, GmbH, Neunkirchen am Brand, Germany) in the same amount (0.5 cc for each implant) and pushed to the sinus through the osteotomy site until the required height of sinus elevation was attained, followed by insertion of the implant fixture (ROOTT, Switzerland). All the implants used in this study were of the same size (8 mm in length × 4.1 mm in diameter). The primary stability was measured, and then the flap was sutured.
Clinical evaluations:
Modified sulcus bleeding index:
Modified sulcus bleeding index was evaluated according to the criteria established by Mombelli et al. (9) These criteria included; a score of 0 when there is no bleeding along the gingival margin; a score of 1 when an isolated bleeding spot is seen; a score of 2 when a confluent red line of blood forms at the gingival margin; and a score of 3 when bleeding is heavy at the gingival margin.
Peri-implant pocket depth (PPD):
Peri-implant pocket depth (PPD) was measured from the pocket base to the gingival margin with a plastic periodontal probe. The probe was inserted at the midbuccal/mesial/palatal/distal sites around each implant; in a line parallel to the vertical axis of the implant until the blunt edge of the probe contacted the pocket base.(11)
Implant Stability Measurement:
Primary stability was checked using the Osstell device (Osstell; Integration Diagnostics Ltd., Göteborg, Sweden) (Fig. 4) by connecting a smart peg to the implant and measuring the value of the implant stability quotient (ISQ). The Osstell device allows for the evaluation of an implant’s stability by resonance frequency analysis (RFA). Implant stability is measured as the implant stability quotient (ISQ), with values ranging from 1 to 100. An ISQ greater than 70 is regarded as the most favorable for implant stability, whereas ISQ values below 60 indicate low primary stability. The ISQ is related to the lateral stability of the implant, which depends on the rigidity of the bond between the bone and the implant surface.(12)
Postoperative Care:
Patients were told to avoid blowing their noses or sneezing for the first 12 h following surgery, to avoid using a straw when drinking for the next 10 days, and to apply cold packs to their cheeks. The following medications were prescribed: ketoprofen 150 mg (Bi-Profenid 150, SANOFI Aventus, Compiegne, France), twice daily for 5 days, and amoxicillin-clavulanate (Hibiotic 1 gm, Amoun, Obour City, Egypt), 1 gm twice daily for 7 days. Metronidazole 250 mg (Flagyl, GlaxoSmithKline, Brentford, UK) was also given thrice daily for 7 days.
Follow-Up and Procedures:
After 10 days, the sutures were removed from the implant site. After 3 months, the prosthetic phase was initiated by physically exposing the implant. The Osstell device was then used to measure secondary stability by recording the ISQ.(13) The gingival former was used for 2 weeks to create the emergence profile; then, the impression was obtained, and the cast was prepared for fabricating the screw-retained restorations. CBCT analysis was performed 6 months after the crestal sinus lift procedure to measure the radiographic changes. The measurement period was adopted from previous studies.(14)
after 6 months, bone height changes were evaluated by measuring preoperative residual bone height and distance from the implant platform to the base of the grafted bone at the middle of the implant (Fig. 6)
Bone Density:
For measuring the bone density (HU), standard rectangular shapes were drawn buccal and palatal to the simulated future implant area in the preoperative CBCT. After 6 months, rectangular shapes were drawn along the palatal and buccal walls from the implant shoulder to the apex. This was performed using a bone-density tool in software.
Crestal Bone Loss (CBL):
Marginal bone loss was measured from the implant shoulder to the crest of the alveolar Bone, buccally and palatally. Two lines were drawn at the shoulder and apex of the implant, and then the bone between these lines was measured buccally and palatally from the apex of the implant to the crest of alveolar bone. The mean crestal bone loss was measured by taking the mean value of both the buccal and palatal CBL.
Statistical Analysis :- The data were collected, tabulated and statistically analyzed by SPSS (Statistical Package for Social Sciences) version 24 .