Volumetric Changes of Labial Soft Tissue Contour Following Different Approaches With Immediate Implant Placement

Hard and Soft Tissue Alterations on the Use of Dual Zone Concept Versus Connective Tissue Graft at Flapless Maxillary Immediate Implant Placement. A 1-year Randomized Clinical Trial and Volumetric Study.

Statement of the problem: Tooth extraction is followed by ridge alteration and soft tissue contour collapse. Different strategies were proposed to limit this collapse however, the ability of these techniques to mimic the original soft tissue contour and to maintain long term stability is unclear. Purpose : The aim of this study is to evaluate the volumetric difference of buccal soft tissue contour as well as the radiographic changes, following tooth extraction and immediate implant placement with dual zone concept versus connective tissue graft. Materials and Methods: Thirty patients with single maxillary anterior or premolar tooth indicated for extraction will participate in this study, 15 patient in each group. Group 1 (test group) will be treated by immediate implant placement (IIP) with particulate bone grafts in the dual zone (the bone zone and the tissue zone) and customized healing abutment. Group 2 (control group) IIP with connective tissue graft (CTG) and customized healing abutment. Patient allocation is random for the 2 groups. Data will be collected pre-surgically and at follow up periods (3,6,9&12 months and 6 months after delivery). Extra-oral scanning of the labial contour will be carried out to evaluate difference in contour gained and will be compared to the original contour and between treatment groups. Radiographic evaluation will be done using CBCT pre-operatively and at 12 months.

After administration of local anaesthesia, the tooth will be extracted by the principle investigator without raising flaps, as atraumatically as possible by using periotomes without disturbing the papillary tissues (minimal traumatic extraction technique). After the extraction of the tooth, the socket will be carefully cleaned to excavate the granulation tissue in the marginal and apical regions. The allocation will be revealed to the principle investigator for the 3 implant groups after implant placement.

Group 1: extraction will occur and then followed by immediate implant placement,using standard implant system protocol preparation of the osteotomy will take place. Initial drill will be placed palatally till final drill reached. Placement of the implant without any raising of the flap will be performed in the correct implant position. Primary stability of the implant will be measured by rotational insertion torque value, to be ≥30Ncm (37). Particulate bone grafts are packed in the gap between the implant and the buccal plate of bone and the tissue (dual zone), Followed by customized healing abutment, the temporary cylindrical abutment twill be screwed to the implant and then flowable composite will be injected at the gingival margin level to adapt to the abutment that will be sand-blasted previously for mechanical retention of the composite, taking the shape of the socket at the marginal gingiva, but will only seal the socket without extending deeper apically in the soft tissue. A buccal groove will be made after the polymerization of this material for easier application. The abutments will be removed for final configurations of the apical part mimicking the emergence profile of the extracted tooth and finishing with laboratory discs and burs. The custom healing screw will then be screwed to the implant with the correct torque.

Group 2: Tooth extraction and immediate implant placement as mentioned. Connective tissue grafts will be harvested from the hard palate and placed at the implant sites in a supraperiosteal partial dissection (pouch technique) prepared at the buccal aspect without using vertical incisions and without flap elevation. Sutures will be used to stabilize the graft in its desired place, then will be covered by a customized healing abutment that will be done as mentioned before.

Inclusion Criteria:

1. Patients who have at least one non-restorable maxillary anterior or premolar tooth with sound adjacent teeth.
2. Adults at or above the age of 18.
3. Intact thick biotype gingival tissue with at least 2mm band of keratinized tissue.
4. Buccal bone thickness should be 1mm or less assessed in CBCT with good apical bone.
5. Sagittal root position type 1 as described by Kan et al(30).
6. Good oral hygiene
7. Patient accepts to provide an informed consent.

Exclusion Criteria:

1. Smokers
2. Pregnant and lactating females.
3. Medically compromised patients. , as Uncontrolled diabetic patients, patients taking bisphosphonates injection for treatment of osteoporosis, patients with active cardiac diseases, patients undergoing radiotherapy or chemotherapy, or any other medical and general contraindications for the surgical procedure (i.e. ASA score ≥III) (31)
4. Patients with active infection related at the site of implant/bone graft placement.
5. Patients with untreated active periodontal diseases.
6. Patients with parafunctional habits