This study is a randomised controlled clinical trial. The patients will be included for the placement of immediate implants with immediate crown placement, to replace maxillary anterior teeth. Any significant differences between the Co-Axis implant and a conventional conical implant will be evaluated.

Introduction: It is commonly known that the placement of an immediate implant is a technique-sensitive procedure, as the implant should be placed in the palatal aspect for the perfect prosthetic emergence and profile. In order to supply this complexity, there is a novel macroimplant design involving an implant with a 12º angled platform. This angulation of the coronal part of the implant allows perfect emergence of the placement of post-extraction implants, since it is placed at the center of the socket, acquiring the best possible bone. In addition, thanks to the angled neck, prosthetic emergence is ideal, as it is corrected and emerges through the cingulate area, thus securing a perfect emergence profile.

Objectives:

Primary Outcomes: Evaluate the percentage of success and survival of the Inverted Co-Axis 12º Southern Implants versus the Internal Conical (Deep Tapered Conical) South Implants on a 1-2-1 follow-up.

Secondary Outcomes:

1. To evaluate the primary stability of both implant systems through a coefficient stability if implants using the Penguin RFA;
2. To evaluate the horizontal and vertical marginal bone loss via a CBCT, 1 year after implant placement;
3. To evaluate the soft tissues via the Pink Esthetic Score (PES) 1 year post-op.

Materials and Methods: Patients were randomly assigned in 2 groups of 15 patients, conical or inverta co-axis implants. Immediate implants in the aesthetic zone of the superior maxilar were placed with an immediate provisional crown restoration. In the same surgery, a connective tissue graft was performed. Only type I sockets according to the Elian Classification were eligible for this study.

Inclusion Criteria:

• Patients who presented with a good well-being status and no contraindication for undergoing an oral surgical procedure
• Patients aged 18 and over
• Adequate oral hygiene, with patient's presenting a plaque index lower than 15% using the Index Scale publish by Löe et al.
• Patients who demonstrated motivation and compiled by attending the allocated follow-up appointments
• One single tooth indicated to be extracted due to having a poor prognosis in the maxilla (central or lateral incisors, canines or premolars)
• Absence of vestibular dehiscence in the bone table and presence of soft tissue without recession (Alveolus type I according to the classification of Elian et al. which could be determined on the day of surgery
• Sufficient bone to allow implant placement with primary stability
• To avoid image blurring or artefacts during CBCT, patients were included if they did not have a bridge or amalgam restoration close to the implant placement.

Exclusion Criteria:

• If the patient presented with an acute infection in the tooth where the implant is to be placed
• Absence of posterior sector in which it would cause an occlusal overload
• Alveolus with enough space to place an implant with a diameter of 4.5mm (since implants with a 3.5 coronal diameter have a widening in the middle third of the implant of 4.5mm)
• Patients with an unstable periodontal status
• Patients who smoked more than 10 cigarettes a day
• Patients who had medical histories which contraindicate implant surgery.