Anterior Implant Rescue: Treating Peri-Implantitis with CIST & GBR

Peri-implant bone loss in the anterior maxilla presents significant functional and aesthetic challenges. This case report describes the successful management of severe peri-implantitis affecting tooth #11 using a structured, two-step protocol: CIST (Cumulative Interceptive Supportive Therapy) for infection control, followed by GBR (Guided Bone Regeneration) for bone reconstruction. Concurrently, endodontic pathology on adjacent tooth #21 was managed to eliminate cross-infection risks. Both functional stability and soft-tissue aesthetics remained stable, with excellent radiographic bone levels confirmed at two years.

• Chief Complaints: Impaired masticatory function and aesthetic dissatisfaction in the anterior smile zone.
• Clinical Findings:

1. Tooth #11 (Upper Right Central Incisor): Progressive peri-implant bone resorption leading to active peri-implantitis and secondary abutment loosening.
2. Tooth #21 (Upper Left Central Incisor): Periapical granuloma associated with a history of recurrent endodontic infection.
3. Tooth #46 (Lower Right First Molar): Severe coronal structural defect with heavy occlusal wear (scheduled for a separate phase of treatment, not included in this anterior report).

• Tooth #11 Protocol (Peri-Implantitis Decontamination & GBR):

1. The existing crown and loosened abutment were removed. After chemical surface decontamination with chlorhexidine and hydrogen peroxide, a healing abutment was placed.
2. The CIST protocol was then initiated to arrest bacterial colonization and control localized inflammation.
3. GBR (Guided Bone Regeneration) was executed using a deproteinized bovine bone mineral (DBBM) xenograft and a resorbable collagen barrier membrane to restore missing alveolar bone volume.
4. Following an uneventful 6-month healing period, a custom final prosthetic crown was delivered.

• Tooth #21 Protocol (Endodontic & Surgical Management):

1. Comprehensive Root Canal Treatment (RCT) was re-initiated to eliminate intradental bacteria.
2. Apicoectomy was performed to surgically excise the persistent periapical granuloma.
3. A fiber post-and-core build-up was placed prior to final crown restoration.

• Clinical Outcome:
  A 24-month post-operative follow-up demonstrated complete resolution of inflammation around tooth #11, significant radiographic bone fill (>3 mm), and a reduction in probing depth from 8 mm to 3 mm, with seamless aesthetic integration into the adjacent natural dentition.