Effects of the SIS Membrane on GBR and Early Loading of Maxillary Anterior Dental Implants

The aim of this randomized controlled trial (RCT) is to determine whether early implant loading that shortens the healing period to 6 weeks can be safely and effectively applied to implants with good initial stability in the maxillary anterior region, which undergoes simultaneous guided bone regeneration (GBR), via clinical examination, intraoral scanning, imageological diagnosis, and aesthetic scoring, and to determine the clinical effect of the small intestine submucosa (SIS) biological barrier membrane in such cases involving early loading. This study is expected to provide preliminary guidance on the timing of loading for a single maxillary anterior implant with insufficient bone volume and provide a theoretical basis for the selection of a biological barrier membrane for GBR in such patients.

Patients were randomized into three groups at a 1:1:1 ratio, including the GBR with a Bio-Gide membrane and delayed implant loading (Gide-DL) group, the GBR with a Bio-Gide membrane and early implant loading (Gide-EL) group, and the GBR with an SIS membrane and early implant loading (SIS-EL) group. The allocation sequence was generated through an online tool (www. random.org) and was concealed in sealed envelopes. At 6 weeks after implant and GBR surgery, the implant stability quotient (ISQ) was measured and recorded at the labial, palatal, mesial, and distal locations via the Osstell device in the Gide-EL group and the SIS-EL group. If the ISQ was ≥ 65, definitive restoration (early loading) was performed (if \< 65, the subject was withdrawn from the trial). The digital impressions and occlusal relationships were obtained via intraoral scanning, and the implant-supported crown was designed based on the digital model. Titanium base abutments with angled screw channels (ASCs) and porcelain veneered zirconia (PVZ) crowns were used for restoration. Immediately after definitive restoration, intraoral scanning was used to record the soft tissue contour at the implant site, and CBCT was used to examine the bone tissue around the implant. In addition, patients in the Gide-DL group underwent definitive restoration at 6 months after surgery (delayed loading), and the treatment process was the same as that in the Gide-EL and SIS-EL groups at 6 weeks after surgery. Clinical examination, intraoral scanning, imageological diagnosis, and aesthetic scoring were used to determine the clinical effect of SIS membranes and early implant loading at 1-year follow-up.

Eligibility Criteria:
Inclusion Criteria:

* patients with single maxillary anterior tooth loss (sites: 12, 11, 21, 22);
* age ≥18 years;
* sex not limited;
* no history of systemic diseases such as heart disease, hypertension, or diabetes;
* no periodontal disease or already received periodontal systemic treatment;
* cone-beam computed tomography (CBCT) revealed that the thickness of the alveolar ridge in the tooth loss area was greater than 3 mm but less than 5 mm;
* using hydrophilic-modified sandblasted and acid-etched (SLActive) bone level tapered (BLT) dental implant systems.

Exclusion Criteria:

* patients receiving radiotherapy and chemotherapy;
* patients with a history of hepatitis, tuberculosis, or other infectious diseases;
* patients with very poor oral hygiene;
* patients who were heavy smokers;
* pregnant women.