1. Patient Selection
This was a retrospective observational study of patients, whose anterior teeth need to be extracted with a defect of labial bone, need immediate implant placement with bone augmentation using bone graft material. From March 2016 to May 2017, 30 patients (12 women; 18 men), with a mean age of 48 ± 16.7 years (range 19 to 67 years) were collected from department of oral and maxillofacial implant research center, Affiliated Stomatological Hospital of Fujian Medical University. All patients were informed about the surgical and restoration treatment procedure. The study design was performed in accordance with the Helsinki Declaration (revised in 2008).
The Inclusion criteria were as follow: (1) Anterior teeth need to be extracted with a defect of labial bone (horizontal or vertical bone defect). (2) the teeth without acute inflammation. (3) Without uncontrolled systemic disease which is not suitable for implantation. (4) Good systemic and oral health. And the exclusion criteria were: (1) Heavy smoker (>10 cigarettes/day). (2) Acute inflammation in the site of implantation and adjacent tissue. (3) A history of radiotherapy in the head or neck region. (4) With systemic disease like uncontrolled diabetes mellitus, coagulation disorders, alcohol or drug abuse not suitable for implantation.
2.Preoperative Work-Up
All patients perform general oral examination and CBCT examination to observe the structure of the teeth which need to be extracted and the labial bone before surgery. Then we measured the available bone width and bone height to determine the treatment program and reach a consensus with patients. All patients got a serial of professional oral hygiene with scaling and root planning two weeks before surgery. For the prevention of infection and better plaque control, all patients were given antibiotic three day before surgery and mouthrinsed with 0.2% chlorhexidine one week before surgery. At the same time, surgeon measured the CBCT to precisely assess the width, the depth and the defect of the labial bone, in order to perform better implant placement and choose the most appropriate implant.
3. Autogenous Tooth Bone Graft Preparation
All the autogenous tooth bone graft’s preparation were done by the same dentist who was well skilled with this technology. Autogenous tooth bone graft material derived from tooth which need to be extracted without the retention value, and prepared following the instructions of vacuum ultrasonic autoclaved bone preparation equipment (VacuaSonic®, Korea). Autogenous teeth without retention value were extracted with a minimally invasive tooth extraction device, under routine local infiltration anesthesia or block anesthesia with Primacaine® (4% Articaine,1/100000 adrenaline, ACTEON) 30mins before surgery. The residual periodontal ligament on root surfaces was removed. Caries and restorations were removed by the grinding needle. Then the tooth was crushed into debris by a hammer in an iron container, meanwhile the dental pulp or canal filling materials was removed. The size of the debris is determined by a sieve. At last the bone debris was put into a vacuum ultrasonic autoclaved bone preparation equipment with different solution according to the manufacture. After demineralization, peracetic acid sterilization and rinse, autogenous tooth bone graft material was prepared eventually as it showed in the Fig 1.
4.Surgical and Prosthetic Proceduce
All the surgeries were performed by the same surgeon with more than 25 years of experience. Tooth extraction was made under local anesthesia with Primacaine® (4% Articaine,1/100000 adrenaline, ACTEON) before surgery. Then the full-thickness midcrestal incision and vertical releasing incision in distal side were made, vertical releasing incision in mistal side was made if necessary. The extraction socket and the labial bone defect were exposed by buccal and palatal flap reflection. Inflammatory granulation tissue was removed before hole preparation. The implant position was marked on the palatal bone wall of the extraction socket with a small round drill (diameter of 2.0 mm). Subsequently, pioneer drill was used to make the right implant depth which is 3-4mm below the gingival level of final restoration and implant position which is at the centerperdetermined mesiodistal width with a minimal distance of 2 mm from the adjacent tooth and a few palatal side of the buccal and palatal aspect. Then the drills were used to expand the hole to the final size step by step, and insert the screw type implant with the cover screw placed. The autogenous tooth bone (atuoBT) or the xenogenic bone (xenoB, Geistlich Bio-Oss ) were used to filled the gap between the facial bone wall and the implant and the defect of the facial bone to reach the enough buccal bone supported, and then the graft materials were covered with absorbable barrier membranes(Bio-Gide, Geistlich). Finally, the flap was repositioned and sutured. The brief process of the surgery is showed in Fig 2. According to implant routine postoperative medical advice, a certain amount of antibiotics was given to prevent wound infection and excessive bleeding. After 4 mouths healing, the prosthetic procedure was performed with a titanium abutment and a zirconium dioxide crown. Patients underwent CBCT examination immediately, 6 months and 1 year after surgery.
5.Outcome Measurements
5.1 Implant Success
The implant success criteria in our study is based on the criteria of Albrektsson, Zarb, Worthington and Eriksson(1986) and of Buser, Weber and Lang(1990). The following are the criteria of the implant success: the absence of mobility, the absence of acute or chronic peri-implant infection, the absence of radiolucency around the implant, without pocket probing depth (PPD) ≧ 5 mm, and without vertical bone loss ≧ 1.5 mm in the first year. The cases will be defined as failure if it can’t reach any one of the success criteria.
5.2 Clinical Assessment
Swelling, wound dehiscence and other adverse events were observed at 3 days and 7 days after implant placement. The guided bone regeneration using different graft material regard as failure when the following clinical feature arisen: emerging of the fistula, the particle of the bone graft material flow out from the fistula or mucosal dehiscence, and the chronic inflammation.
5.3 Radiographic Assessment
All the patients were measured by CBCT scanning before implant placement, immediately after implant placement, 6 months and 12 months follow-up. And all the measurements were done by one dentist who did not know which group is. Marginal bone level and horizontal bone change at the facial side of implant were measured. The centre of the implant was set as a vertical reference line in the CBCT image and all the measured point is perpendicular to it. We measured the labial horizontal bone width perpendicular to the vertical line of the implant surface at the implant neck level or the top of the buccal bone (which is regarded as 0mm), 3 mm and 6 mm apical to the implant neck level as it shown in Fig 3. The stability of the labial horizontal bone was evaluated by the percent of the horizontal bone loss. And the percent of the horizontal bone loss at each time point and each measured point were calculated by the following formula: (width of base line – width of following-up time)/ width of base line. Also the marginal bone level (MBL) at the implant neck level was measured at different following-up time according to the CBCT image.
5.4 Patient Satisfaction Evaluation
Patient satisfaction was evaluated by a questionnaire based on the Visual Analog Scales (VAS 0-10), which is focused on the pain, swelling, satisfaction of the surgery process. All patients answer the questionnaire at the time of removing the suture.
6 Statistical Analysis
The data about the percent of the horizontal bone loss, marginal bone level at different following-up time and between different bone graft materials were compared with each other using the Independent-Samples t-test with the SPSS 22.0 software. So did the results of the questionnaire. The percent of the horizontal bone loss at different measure level were compared with each other using one-way ANOVA. P values < 0.05 were defined as statistically significant.