immediate implant placement using the VST was compared to early implant placement protocol using Buser's technique regarding implant survival, changes in labial plate thickness and soft tissue height after 1 year of implant placement

Preoperative procedures A preoperative radiograph was performed for all patients for diagnosis and treatment planning purposes. Non-surgical periodontal treatment was done as needed. Impressions were taken and casted in stone for the fabrication of the surgical templates.

Surgical protocol As dictated by the randomization patients were assigned to either Buser's technique or to the VST. In the VST group, atraumatic tooth extraction was carried out using periotomes (Stoma, Storz am Mark GmbH, Emmingen-Liptingen Germany) under local anaesthesia (ARTINIBSA 4% 1:100.000. Inibsa Dental S.L.U. Barcelona, SPAIN).

Vestibular socket therapy (VST) included the following steps. a-traumatic tooth extraction, the socket curetted and rinsed with normal saline thoroughly. One-cm long vestibular access incision was made using a 15c blade (Stoma, Storz am Mark GmbH, Emmingen-Liptingen Germany) 3-4 mm apical to the mucogingival junction at the related socket . A subperiosteal tunnel was created connecting the socket orifice and the vestibular access incision using periotomes and micro periosteal elevators (Stoma, Storz am Mark GmbH, Emmingen-Liptingen Germany). Implant fixture (Biohorizons, Birmingham, Al, USA) were then inserted after drilling to its pre-planned location 3-4 mm apical to socket base with adequate primary stability achieved using a torque wrench reaching 30 Ncm torque . A flexible cortical membrane shield that is made of cortical bone of heterologous origin of 0.6 mm thickness (OsteoBiol® Lamina , Tecnoss®, Torino, Italy) was hydrated and then trimmed and introduced from the vestibular access incision reaching 1 mm below the socket orifice through the tunnel then stabilized using a membrane tack or a micro screw to the alveolar bone apical to the base of the socket (AutoTac System Kit, Biohorizons Implant Systems, Birmingham , Alabama Inc, USA) . The socket gap between the implant and the shield was then packed thoroughly with particulate bone graft (75% autogenous bone chips and 25% deproteinized bovine bone mineral (DBBM).

In Buser's group early implant placement, the failing tooth was extracted atraumatically using a periotome. A collagen plug was placed to stabilize the wound clot. A healing period of 4-8 weeks (depending on the size of the extracted tooth) was followed. Then an open flap implant surgery using a triangular flap design was cut. A slightly palatal incision in the edentulous area is done, with the incision made along the inner surface of the palatal bone wall deep into the socket allowing the entire regenerated soft tissue to be part of the buccal flap. After preparing the implant bed, the site was irrigated using normal saline. Implant was then placed under the crest of the palatal bone. A healing abutment was then attached.The bone graft was placed in a layered manner, where the cortical bone chips were placed first followed by the bio-oss activated mix. A non-cross liked membrane was then placed, after being soaked with BCM. Finally, the healing abutment was removed and the flap was released to allow for its suturing.

Inclusion Criteria:

• all patients were adults ≥ 18 years
• 1-5 non-adjacent hopeless maxillary teeth in the esthetic zone.
• The involved teeth had type II sockets.
• To achieve optimum primary stability for the implants (30Ncm insertion torque), adequate palatal and at least 3 mm apical bone should be available to engage the immediately placed implants.

Exclusion Criteria:

• Smoking and/or pregnant patients
• systemic diseases
• a history of chemo- or radiotherapy within the past 2 years were excluded.
• Infected sockets were also excluded.

AE and IR were responsible for measuring the outcomes and they were blinded to the treatments, since they were not involved in the treatment The statistician was also blinded to the treatment.