What is a SIMI Procedure?
"SIMI" refers to "simultaneous" implant placement, meaning a dental implant is placed at the same time as another procedure—most commonly bone augmentation (guided bone regeneration/GBR) or immediately after tooth extraction.
Understanding SIMI in Context
The term "SIMI" is shorthand for simultaneous procedures in implant dentistry, where two interventions occur during the same surgical visit rather than being staged separately. This contrasts with staged approaches where procedures are separated by healing periods.
Most Common SIMI Applications:
1. Simultaneous Implant Placement with Lateral Ridge Augmentation (LRA)
- The implant is placed while bone grafting material and membranes are used to augment deficient bone width at the same time 1
- This approach is chosen when there is insufficient lateral bone volume but enough stability can be achieved for the implant
- Requires adequate primary stability of the implant despite the bone deficiency
2. Immediate Implant Placement (Type 1)
- The implant is placed immediately into the extraction socket at the time of tooth removal 2
- This is technically a "simultaneous" procedure—extraction and implant placement occur in one visit
- Requires specific conditions: intact facial bone wall >1mm thick, sufficient apical bone for stability, thick soft tissue biotype, and no acute infection 2
Key Decision Points for SIMI vs. Staged Procedures
Choose SIMI (simultaneous) when:
- Primary implant stability can be achieved (≥35 Ncm torque) 3
- Bone defects are moderate and contained
- The facial/buccal bone wall is intact (for immediate placement)
- Patient has thick soft tissue biotype
- No active infection is present
Choose staged procedures when:
- Thin or damaged facial bone wall prevents adequate implant positioning 2
- Extended bone lesions exist apically
- Large periapical pathology is present
- Insufficient bone volume prevents primary stability
- Patient is too young for definitive implant therapy 2
Clinical Implications
The simultaneous approach reduces treatment time and the number of surgical interventions, improving patient acceptance. However, it demands precise case selection and surgical skill. The predictability of achieving the desired outcome should be the decisive factor in choosing simultaneous versus staged approaches 1.
For anterior esthetic sites, simultaneous procedures with immediate provisionalization can achieve favorable outcomes when selection criteria are strictly followed, with good to excellent esthetic results documented at 6-9 year follow-ups 2.