Minimal guided bone regeneration procedure for immediate implant placement in the esthetic zone
A 28-year-old male patient reported to the Department of Periodontology and Oral Implantology with a chief complaint of a fractured crown in relation to root canal treated maxillary left central incisor. The patient had undergone root canal treatment of the tooth 3 years back and had received fixed bridge prosthesis in relation to the bilateral maxillary central incisor regions. The patient reported that the prosthesis got avulsed and the crown portion of the maxillary left central incisor was fractured following the biting into a hard food substance. The patient also reported the previous dental treatment to be unsatisfactory in terms of the final esthetic and functional outcomes of the prosthesis. Patient expressed preference for a single crown prosthesis and considered his previous bridge prosthesis, a failure in simulating the natural tooth appearance. There were no other relevant dental and medical histories. The patient was a teetotaler and his family history was non-contributory, whereby the confounding environmental and genetic risk factors were deemed absent. Intraoral examination revealed a fractured root canal treated maxillary left central incisor. The right maxillary central incisor had undergone tooth preparation as a part of the previous bridge prosthesis. Oral hygiene maintenance was satisfactory and on examination, the gingival and periodontal status of the patient also appeared to be apparently healthy.\nThe patient was explained in detail about the various treatment modalities available, the advantages and disadvantages of each type of therapy as well as the cost factor related to each therapeutic mode. Taking into consideration the esthetic and functional demands in the anterior esthetic region and the patient's request for an implant-based fixed prosthetic rehabilitation, the final treatment plan was formulated. An atraumatic extraction of the fractured, root canal treated maxillary left central incisor and an immediate implant placement was decided upon as the final treatment plan for the patient. A written informed consent was obtained from the patient prior to commencement of the surgical procedure.\nThe surgical site was anesthetized by local administration of 2% lignocaine hydrochloride (LOX, Neon Laboratories Ltd., Mumbai, India) with 1:200,000 adrenaline. A modified crestal incision was made beyond the palatal surface of the tooth. The conventional mid-crestal incision was placed just apical to the palatal margin of the fractured tooth. This incision was then continued with the oblique releasing incisions placed along the mesial line angles of the maxillary right central and left lateral incisors, extending beyond the mucogingival junction to obtain a tension-free flap with a broad base. This type of envelope flap design with two releasing incisions is called the four corner flap. This mucoperiosteal flap was reflected and the fractured tooth exposed sufficient enough to facilitate atraumatic and careful extraction []. The tooth was extracted by conventional forceps technique and the socket was thoroughly curetted for complete removal of infected granulation tissue, if any. The socket was flushed with sterile isotonic saline solution and osteotomy site preparation was performed for receiving the implant. A self-threaded titanium implant (4.2 mm × 10 mm, Lifecare Devices Pvt. Ltd, Chennai, India) was inserted at the extraction socket and adequate primary stability was accomplished from the residual alveolar bone. However, a small amount of space was present at the palatal and proximal surfaces of the implant in the cervical aspect []. Autogenous bone harvesting was decided upon and the patient was explained in detail regarding the procedure. A second written informed consent was obtained from the patient prior to proceeding with the bone harvesting procedure.\nAutogenous block bone graft was harvested according to the “minimum button-hole” technique described by Kumar et al. in 2011.[] A minimal vestibular incision was placed apical to the roots of mandibular left incisors. Soft tissue attachments were carefully relieved using a periosteal elevator until mandibular symphysis bone in the size of a “button-hole” was exposed. An 11 mm diameter cylindrical autogenous block bone was harvested using a round trephine bur []. Next, the block bone graft was crushed into bone chips using a bone rongeur.\nThe bone chips were carefully packed around the palatal and proximal aspects of the implant []. A bio-resorbable collagen membrane (Healiguide, Advanced Biotech Products, Chennai, India) was adapted over the implant site to establish complete coverage and protection of the implant and bone graft material []. The recipient and donor sites were sutured using an absorbable suture material (4-0 Vicryl, Ethicon, Inc., Johnson and Johnson, Somerville, NJ, USA).\nA prescription of 8 mg of betamethasone was given jointly with 2 g/day of amoxicillin for 10 days. The patient was advised to rinse with warm salt water rinses for the initial 15 days to promote wound healing. The patient was also instructed in the use of chlorhexidine gluconate 0.12% (Peridex, Zila Pharmaceuticals, Phoenix, AZ, USA) as part of home care regime. The patient experienced very minimal post-operative discomfort and no complications were reported.\nIn order to protect the recipient site and eliminate undue stress and forces from acting upon the surgical area, the placement of a temporary prosthesis was avoided with a mutual consent obtained from the patient. This ensured an undisturbed interior milieu facilitating appropriate healing of surgical site. Six months post-operatively, the recipient and donor surgical sites exhibited excellent wound healing with adequate amount of interdental papilla present at the recipient site around the implant fixture []. A second phase surgery was performed to uncover the implant, and the final fixed prosthesis involving two separate crowns were delivered in relation to both the maxillary central incisors []. The separate crown suprastructures were fabricated keeping in mind the patient's request and preferences. The patient was extremely satisfied with the final outcome of the restoration, fulfilling both esthetics and functional needs.