Treatment of an early failing implant by guided bone regeneration using resorbable collagen membrane and bioactive glass
A 35-year-old female patient was referred to the Department of Periodontology and Implantology, Bapuji Dental College and Hospital, Davangere, Karnataka State, for the implant placement in the upper front tooth region. The tooth was removed 6 months back due to excessive mobility. The patient was systemically healthy and non-smoker.\nClinical examination revealed missing upper right lateral incisor (#12) with other neighboring teeth in good health and alignment. The patient was maintaining good oral hygiene and showed keen interest in undergoing implant therapy. A written consent form was submitted by her. Necessary investigations like complete hemogram, intra-oral periapical (IOPA) radiograph [], and computed tomographic (C.T.) scan of the edentulous site were done [Figures –]).\nC.T. scan measurements revealed inadequate bone volume labio-palatally to accommodate a standard-diameter implant []. The patient did not accept the suggested treatment modalities to augment the deficient labio-palatal bone due to increased expense and prolonged time for several stages, until tooth reconstruction. Therefore, a decision was taken to place a mini implant. The implant used was TRI-N-SR mini implants (Hi-Tech Implants, Herzlia, Israel). This is a threaded, self-tapping, uncoated titanium alloy implants and is available in 10 mm and 13 mm lengths with a fixed diameter of 2.4 mm. The TRI-N-SR mini implant is a single-piece implant with large grit sand blasted and acid etched surface (SLA) and with a smooth polished collar and abutment surface. According to the measurements obtained with the help of C.T. scan, a 10 mm long implant was selected and placed according to the manufacturer's instructions. The insertion torque achieved was only 20 Ncm (indicating less primary stability), and therefore an immediate provisional acrylic restoration was avoided. A decision was made to directly give a final porcelain fused-to-metal (PFM) prosthesis to the patient at the end of 6 weeks, as an early loading protocol. Since it was a one-piece implant, the patient was instructed to follow an appropriate soft diet for 1 week, and avoid putting any kind of excessive load on the implant. The patient reported 10 days after the procedure for the removal of the sutures. The soft tissue healing was satisfactory and there was no clinical mobility of the implant at this time. The patient was now asked to report back at the end of 6 weeks for the fabrication of permanent prosthesis.\nWhen patient returned at the end of 6 weeks, overall periodontal examination revealed fair oral hygiene according to OHI-S index by Green and Vermillion. A periodontal diagnosis of dental plaque-induced gingival disease – gingivitis associated with dental plaque only without other local contributing factors was arrived at, after thorough clinical examination. However, grade I mobility (according to the Misch's Clinical Implant Mobility Scale) was detected with respect to the implant placed. The Misch's Clinical Implant Mobility Scale uses two rigid instruments to apply a labio-lingual force of approximately 500 g and grades mobility of implant according to the following scale []. The peri-implant probing depth was 6 mm on the mesial and 5 mm on distal aspect. Bleeding on probing was also positive. Intraoral periapical (IOPA) radiograph revealed bone loss on both mesial and distal aspects of the implant [Figures and ]. A clinical diagnosis of failing implant was made and a decision was taken to salvage the failing implant by means of GBR procedure to regenerate the lost bone.\nAntibiotic (amoxicillin 500 mg/potassium clavulanate 125 mg tabs, three times daily) was started a day prior to the surgical procedure. Under antibiotic cover, local anesthesia was given, intra-crevicular incisions were placed, and full-thickness mucoperiosteal flap was reflected. The infected granulation tissue was removed from the defect and the implant surfaces were thoroughly debrided using plastic curettes (Straumann® Dental Implant System, Straumann AG, Basel, Switzerland). A circumferential defect with slight buccal bone loss was evident around the implant [Figures and ]. Next, surface decontamination was done by applying a supersaturated solution of citric acid for 30 s followed by complete rinsing of the site with normal saline [].\nThe peri-implant defect was filled with PerioGlas® (NovaBone Products, LLC, Alachua, Florida, USA) starting from the bottom of the defect [Figures and ]. However, the graft material was moistened in sterile saline before placement into the defect. Following grafting, the bio-resorbable type-I bovine collagen membrane (Healiguide®, Advanced Biotech Products Pvt. Ltd., Chennai, India) was trimmed and adapted over the entire defect so as to cover 2-3 mm of the surrounding alveolar bone and to ensure stability of the graft material [Figures and ]. Primary wound closure was achieved, using non-resorbable 3-0 black braided silk sutures (Mersilk®, Ethicon, Johnson and Johnson, India) and the area was covered with periodontal dressing (Coe-pak, G. C. India) for 7 days [Figures and ]. The patient continued with the antibiotic coverage 1 week postsurgery and was also instructed to rinse twice daily with 0.2% chlorhexidine (Clohex, Dr. Reddy's laboratories ltd., India). The dressing and sutures were removed after 7 days. The patient was asked to continue with 0.2% chlorhexidine for 3 weeks and to avoid brushing this region for the same time period. Regular recall was done, once every month for 6 month period.\nAt the end of 6 month follow-up, the healing was found to be complete with a clinical evidence of healthy and firm mucosa around the implant [] and no sign of clinically detectable implant mobility. Intraoral periapical (IOPA) radiograph showed complete resolution of the treated defect, which may be due to regeneration of bone [].\nAfter obtaining satisfactory clinical outcome, the process of fabrication of definitive prosthesis was taken up. The axial surfaces of the implant were modified using multi-fluted carbide burs under copious irrigation. The reduction of the axial surfaces was kept as minimum as possible. As the abutment was modified intraorally, an impression coping and implant analog could not be used. Hence, a direct pick up impression was made using additional silicone material, without the use of any impression coping, and the cast was poured using type-4 dental stone. Shade selection was also done during this appointment, and finally, the definitive porcelain fused-to-metal prosthesis was fabricated in the laboratory and delivered to the patient [Figures –] with the best satisfaction of the patient.