When mini implants are splinted in fixed partial or complete dentures, the adjacent implants are anchored to each other, dissipating force and minimizing the potential for implant micromovement. However, cement ported prostheses to prevent this complication. The most retentive metal-to-metal cements are the resins and resin-modified glass ionomers. Care should be taken to ensure that the surface tension of the mixed cement does not prevent the cement from reaching the deepest part of the casting during the cementation procedure. Mini implants are one piece and do not have separate abutments. Thus, there is no micro-gap issue. The coronal portion of the implant is the abutment and can be prepared for parallelism. A conventional crown and bridge impression technique is appropriate. Polyvinyl siloxane materials provide a satisfactory impression with little tissue toxicity.
The coronal portion of the implant may require preparation to ensure parallelism and a passive fit. The implant surgeon should take care to place the mini implants closely parallel so that only minimum or no preparation is required. Excessive preparation may predispose the corona to metal fatigue fracture. Natural teeth have periodontal ligaments and intrude under an occlusal load to as much as 200 mm. Implants do not intrude under an occlusal load. During clenching and grinding, the implant-supported prosthesis may be the only contact and may thus bear the full force of occlusion (26). Each patient is different in this regard, and this tooth intrusion is difficult to measure, so a builtin prosthetic occlusal relief or a gap in unforced maximal intercuspation of approximately 100 mm may be appropriate. This ensures that the implant-supported prosthesis will not bear the full force of the jaws during clenching.