If you live in the Buffalo area you’ve probably heard of mini dental implants. Many patients come to our office and have many questions such as what is a mini dental implant and how is that different than a standard dental implant. I will surely answer this and any other questions that you may have around this.
What is a mini dental implant (AKA MDI)?
A mini dental implant is an extra narrow titanium screw that is meant to integrate to bone provide support for a prosthetic. Usual diameters are less than 2.9 mm.
What is a standard or conventional dental implant? A conventional or standard dental implant is a root form titanium screw that is meant to integrate to bone to provide support for a prosthetic. Usual diameters are anywhere from 2.9 mm to 5.8 mm.
What are the differences between an MDI and a conventional implant?
Other than the obvious differences of diameter and the mechanical problems that can be associated with withstanding stresses, MDIs and standard dental implants have different connections between the implant and the restoration. The weakest link in the chain of implant and restoration is connection between the implant and restorative part. In a conventional implant there is an intermediate part called an abutment. The abutment connects directly to the implant via an internal hexagonal shaped connection that resists rotation. Additionally it connects to the implant with a screw that is torqued to manufacture specification, which is usually about 30 Ncm^2.. Finger tightness is nowhere near this torque pressure. This secure connection then serves as the base on which the crown is cemented. Sometimes the crown and abutment are fabricated in 1 piece. However in this case the 1 piece is screwed in to the implant through the internal hex connection.
MDI’s on the other hand have no such internal connection. Because of their narrow connection they can only accommodate a connection on the outside of the implant. Usually the implant has a small ball on the top with which it attaches the crown.
Is one type of implant superior to the other in the case of single tooth restoration ?
Yes, the standard implant is superior because of the superior connection of the restoration to the crown. The external (or ball to crown) attachment of the MDI is inferior and can lead to failure by way of fracture, micro-movement (torsion/or twisting of the crown on the implant) or loss of the restoration due to inadequate retention.
Why do they make MDIs? MDIs have long had a role in retaining removable dentures in cases where inadequate bone is present or cost is a factor. The ball design of these implants make them a good candidate for retaining removable dentures while there narrow design make them good candidates for placement in narrow jaws without the need for bone grafting.
Do you place MDIs? No, we here at Niagara Dental Implant & Oral Surgery do not place MDIs. In cases were MDIs would work we are able to either place a narrow 2.9 mm or 3.0 mm standard implant or grow bone by way of grafting to accommodate a standard implant.
Why don’t you place MDIs in cases where they might work? Because of their inferior mechanical qualities we do not feel that these implants would be the best implants to place. Also, sometimes patients may want to change the type of restoration that is supported by the implant. In the case of MDIs that would be very difficult. In fact, it would require removal of all of the mini dental implants and replacing them with standard or conventional dental implants.