Small Diameter (Mini) Implant/Abutments
Posted on 10/16/2013
In a recent article entitled “Mini Implants: Insights from Dr. Gordon Christensen”*, Dr. Christensen discusses some of the advantages of the small diameter (mini) implants. Among the benefits of the mini implant over the standard diameter implant, Dr. Christensen lists easier surgical technique, quicker healing time and immediate loading. In addition, the cost to the patient can be lower since there is usually no need for a separate abutment and the surgery can be done by the general dentist.
He notes some general rules of thumb when placing the mini implant, that we felt were good advice and we’ve summarized them below:
1. A facial-lingual radiograph (either a tomograph or a CBCT scan) is highly suggested to help with choosing the ideal location.
2. Soft tissue should not be more than 2mm on the crest.
3. A 13mm implant is the average and preferred length
4. Implants should not diverge by more than 15 degrees
5. Mini implants are not recommended for patients who are bruxers
We would like to add some additional points to this from our experience in the lab. For removable appliances, we feel that the mini implant is a terrific option. We have had a great deal of success fabricating standard dentures to be supported over mini implants.
However, we have seen the use of mini implants for fixed cases and these have often been quite problematic. Among the challenges for the lab are:
1. Models are extremely difficult to pour accurately unless an abutment/implant analog is provided. Even an epoxy material does not always capture the abutment well – and it usually tears the impression.
2. The crown over the mini implant often has a poor emergence profile due to the narrow abutment platform.
3. Fear of gingival recession often leads the dentist to request the crown to look like a “Full Ridge Lap Pontic” where the crown extends beyond the abutment margin to the gum. This places an undue pressure on the implant and often creates a food trap. It is not recommended.
In light of these issues, we highly suggest the use of a secondary abutment to be either cemented or screwed down to the mini implant. This often solves the lab side issue and allows for a more esthetic final
restoration.
Wishing you luck with your next mini implant case!
He notes some general rules of thumb when placing the mini implant, that we felt were good advice and we’ve summarized them below:
1. A facial-lingual radiograph (either a tomograph or a CBCT scan) is highly suggested to help with choosing the ideal location.
2. Soft tissue should not be more than 2mm on the crest.
3. A 13mm implant is the average and preferred length
4. Implants should not diverge by more than 15 degrees
5. Mini implants are not recommended for patients who are bruxers
We would like to add some additional points to this from our experience in the lab. For removable appliances, we feel that the mini implant is a terrific option. We have had a great deal of success fabricating standard dentures to be supported over mini implants.
However, we have seen the use of mini implants for fixed cases and these have often been quite problematic. Among the challenges for the lab are:
1. Models are extremely difficult to pour accurately unless an abutment/implant analog is provided. Even an epoxy material does not always capture the abutment well – and it usually tears the impression.
2. The crown over the mini implant often has a poor emergence profile due to the narrow abutment platform.
3. Fear of gingival recession often leads the dentist to request the crown to look like a “Full Ridge Lap Pontic” where the crown extends beyond the abutment margin to the gum. This places an undue pressure on the implant and often creates a food trap. It is not recommended.
In light of these issues, we highly suggest the use of a secondary abutment to be either cemented or screwed down to the mini implant. This often solves the lab side issue and allows for a more esthetic final
restoration.
Wishing you luck with your next mini implant case!
