Study design; in-/exclusion criteria
Medical records were selected among those patients who had been treated with immediate post-extraction implants and performed GBR protocol using bone grafting either MC (Allgens®, Beijing Allgens Medical Science and Technology Co., Ltd., China) or Bio-Oss ( Bio-Oss®, Geistlich Biomaterials, Wolhusen, Switzerland) at the Department of oral and maxillofacial surgery of Shandong Provincial Hospital Affiliated to Shandong University (Jinan, Shandong Province, China), in the period between January 2018 and December 2019.
(2) Type I sockets or intact vestibular wall 38
(3) No acute infection at the extraction site 39
(4)Sufficient volume of apical and palatal bone at the extraction site to allow implant placement in a correct 3D position with primary stability 39.
(5) Good general health
(6) Good oral hygiene
Especially, patients included in this study had to be followed for a minimum period of 1 year after surgery.
(1) Contraindication for surgery such as uncontrolled diabetes, pregnancy, previous or current radiation or immunosuppressive therapy.
(2) Smoking (over ten cigarettes per day) and excessive drinking.
(3) Patients with any systemic disease that could affect bone healing were excluded from the study.
Patients were divided into two groups: the Trail group who were grafted with MC and the Control group with Bio-Oss. All the treatments were arranged consecutively at the Department of Oral maxillofacial surgery of Shandong Provincial Hospital Affiliated to Shandong University. Patients were informed about the treatment purpose, process, and the possible risks of this study, then signed the informed consent.
In order to evaluate the extraction sites, clinical examination and CBCT were taken for each patient. Periodontal treatment and oral hygiene instructions were treated to all patients for better oral environment. Each patient was received antibiotics (Roxithromycin Capsules of 150 mg) 1 hour before surgery and rinsed with 0.2% chlorhexidine gluconate for 1 minute.
All patients were performed by Dr. Huang. Articaine (4% articaine with 1:100000 epinephrine) was used as local anesthetic. The whole operation was carried out with flapless method as atraumatically as possible. Incisions were made from the one side gingival groove of adjacent teeth to the other without vertical incisions. A full-thickness mucoperiosteal flap was raised to facilitate tooth extraction and minimize trauma to the buccal bone plate during extraction. The tooth was extracted using atraumatic extraction technique and the granulation tissue was carefully removed with curette.
Following the instructions of implant manufacturer, the preparation of the implant site was performed rinsed with abundant sterile saline. The pilot drill was conducted to the palatal wall. According to socket size, implant diameter was determined to achieve>1.5mm mesio-distal implant distance and the length of implant was 11.5-13 mm. The implant was inserted with 35Ncm or more and 1 mm below the most apical bone peak. Then the healing abutment was placed. Implant sits were treated with guided bone regeneration. In all cases (not related to the socket configuration or defect morphology), bone substitute material was applied in the residual gap and above the buccal surface of the implants in excess. In Trial group, surgery was performed using MC, while Control group was placed with Bio-oss. The membrane (Heal-All® Oral Cavity Repair Membrane, Yantai Zhenghai Bio-tech Co., Ltd., China) covered the graft site gently. The buccal flap was coronally positioned and the suture was placed with special care to obtain primary closure over the implant using 3/0 Vicryl sutures (Vicryl Rapid-Ethicon Johnson, Diegem, Belgium). CBCT (ProMax 3D, Planmeca OY, 00880 Helsinki, Finland) scans for each patient were performed to confirm proper implant placement after surgery.
Patients were postoperatively instructed to take roxithromycin (150mg ×2/day for 5-7 days) and 0.2% chlorhexidine gluconate twice a day for 14 days. Sutures were removed 7-10 days after surgery.
The reconstructive treatment protocol was performed 6 months after implantation. The patients were scheduled to take CBCT to observe the alveolar bone change. Standard implant impression was made using silicon rubber impression material (DMG, Hamburg, Germany) for permanent restorations. All clinical procedures of permanent restoration were operated by Dr. Han.
The time immediately postsurgery, 6 months and 12 months after permanent restoration were respectively set as T1, T2, and T3. Patients were recalled at T3 to record implant survival rate and give a clinical examination.
Evaluation criteria and methods
Implant survival and complications
Implant survival and complications were observed at 12 months after the final crown delivery. According to Buser's criteria for successful implant osseointegration 40, the success criteria are as follows:
- No persistent subjective complaints, such as pain, and/or paresthesia
- No recurrent peri-implant infection with suppuration
- No mobility
- No continuous radiolucency around the implant
- Possibility for restoration
CBCT was scheduled to assess the osseointegration process at T1, T2, and T3 followed by Yang et al41. Specific fixed reference points were selected in the images to obtain the same tri-dimensional position of the measurement axis. The reference landmarks were defined as follows.
• Implant shoulder (I).
• Top of the bone crest (C)
• Implant shoulder to labial bone crest (OC)
• Horizontal distance between OC and I (OCI)
• Vertical distance between I and C (ICH)
Dimension changes of labial bone were measured by OCI and ICH at T2and T3 compared to T1. This measure defined as ΔOCI and ΔICH was taken at least three times, and the mean values were recorded.
All 70 patients were scheduled to recall at T3. A digital camera (Canon 6D, Canon Inc., Tokyo, Japan) was used with the same parameters to obtain standardized digital photographic records which were taken at the occlusal plane and centered at the contact region of the upper incisors.
The esthetic outcome and performance were evaluate by the pink esthetic score (PES) described by Belser et al 42. The PES contains the following five variables: mesial papilla, distal papilla, curvature of the facial mucosa, level of the facial mucosa, root convexity/soft tissue color and texture at the facial aspect of the implant site. A score of 2, 1, or 0 is assigned to the parameters above. Thus, the maximum score for optimal soft tissue is 10. The PES were objectively determined by three independent examiners who were not involved in the surgical procedure.
Visual analog scale (VAS) evaluation of patient satisfaction
Patient satisfaction related to the esthetic outcome, pain, and swelling was measured with VAS by filling out a questionnaire at T3. Answers were recorded ranging from 0 to 10 labeled with “0 = totally unsatisfied, no pain, no swelling” and “10 = fully satisfied, extreme pain, extreme swelling” 43.
Data analysis was performed using SPSS 16.0 software (SPSS Inc., Chicago, IL, USA). Results were demonstrated as the mean ± standard deviation (SD). The t-test was used to compare the variables. P < 0.05 was considered statistically significant.