The ‘mini’-implant has arrived

Gordon J. Christensen, DDS, MSD, PhD

Historically, the initial users of most types of dental implants mainly were general dental practitioners, who often were severely criticized by their peers for their involvement with implants. During the evolution of and the initial successful use of implants, practitioners still did not accept implant dentistry. With the introduction and refinement of the osseointe-grated root form implant over the last 40 years, implant dentistry has been accepted slowly by both general and specialty practitioners. Root-form dental implants have allowed many types of difficult oral treatment to be accomplished that were nearly impossible before the introduction of implants.^1–4 When root-form implants were popularized, oral surgeons, periodontists, some prosthodontists and a few general dentists became involved in placing them. However, the high cost of implants for patients and the assumed difficulty in placing them has impeded implant use to the degree that they are achieving only a small part of the service potential of which they are capable.

Implants are achieving only a small part of the service potential of which they are capable. 

As a prosthodontist who has placed root-form implants for more than 20 years, I have encouraged interested, surgically oriented general dentists and prosthodontists to place root-form dental implants in healthy patients who have adequate bone. My motivation of general dentists often has been met with criticism by surgical specialists, but I stand behind my recommendations that the more dentists who take the time to become educated adequately in the surgical aspects of implant placement, the more patients will be served by this superior treatment. It is well-known that implants are used widely in many countries that lack the legal obstacles found in the United States.

As interested dentists become involved in implant dentistry, they may want to consider joining the implant organizations and attending their meetings. These groups include the American Academy of Implant Dentistry, the Academy of Osseointegration and the International Congress of Oral Implantology. The oral surgery, periodontal and orthodontic specialty organizations also provide many continuing education courses on implant dentistry.

In my opinion, the increasingly popular “mini”-implant concept will assist the movement of general dentists into implant placement, and it will serve many dental patients who would not have been able to have typical standard-sized, root-form implants.

This article includes a discussion of mini-implants and their potential uses in dentistry.

When the original root-form implants were introduced, they had a diameter of about 3.75 millimeters. Although I have heard various reasons for selection of this diameter, the logic or research supporting these reasons has been unclear. An implant of nearly 4 mm in diameter requires at least 6 mm of bone in a facial-lingual dimension for placement without grafting additional bone to augment the site. After years of placing implants in all locations of the mouth, it is my observation that seldom do I see 6 mm of bone in a facial-lingual dimension. Often, an osteotome must be used to widen the osteotomy and the minimal bone, thereby allowing placement of the 3.75-mm implant in the less-than-adequately sized bony site.

Some implant companies have recognized the challenge of minimal bone presence and made implants of a smaller diameter (ranging from 3 to 3.5 mm). Although this change is only a slight reduction in diameter, it has allowed easier placement of root-form implants in the maxillary lateral incisor area, mandibular anterior sites or in any area in which bone has shrunken. These slightly smaller-diameter implants have been used widely and have been successful, in spite of allegations that they would be too weak.

In the last few years, root-form implants ranging from 1.8 mm to slightly more than 2 mm in diameter have been promoted for long-term service. These so-called “mini”-diameter implants have been used successfully as interim implants to support provisional prostheses, while larger-diameter implants were integrating into bone. When minis were used as interim implants, the intent was to remove the mini-implants when the larger-diameter implants were put into service. As might have been anticipated, when attempting to remove these interim mini-implants, practitioners found that they could not be removed, because they had integrated into the bone during the interim service period. As a result, some of the companies producing mini-implants have applied for approval of the small-diameter implants for long-term use. The first company approved for long-term use was IMTEC (Ardmore, Okla.), makers of Sendax MDI and MDI Plus, in August 2003.

The increasingly popular ‘mini’-implant concept will assist the movement of general dentists into implant placement. 

 

The diameter of root-form implants ranges from approximately 1.8 mm to approximately 6 mm. Three general categories of implant diameters are available: the mini-implant (1.8 mm), the standard-sized implant (3.75 mm) and the wide-body implant (6.0 mm), with all sizes in between. Use of mini-diameter implants is increasing, and more research publications and clinical technique articles about them are becoming available.^5–14 Use of large-diameter implants (6 mm) also is increasing for situations in which inadequate bone is available in a crestal-apical dimension, but adequate bone is available in a facial-lingual dimension.

Bradley J Engle, DMD MHS
5659 Naples Blvd
Naples, FL 34109

http://www.engleimplantdentistry.com
Tel: (239) 593-2178
Fax: (239) 593-2179
Email: info@engleimplantdentistry.com

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