Mini dental implants

Mini dental implants (MDIs) are small diameter dental implants.

Dental implants may be split into two separate categories based on the diameter of the device. Small diameter dental implants, most often referred to as ‘Mini Implants’, are those with a diameter less than three millimeters (3mm.) Likewise, standard or conventional implants are those implants larger than 3mm in diameter, but most commonly 4- 5mm. As a rule of thumb, Mini Dental Implants are at least half the price of conventional implants and sometimes a quarter of the price of conventional implants.^[1][2]

Mini dental implants, or MDI's, are sometimes referred to as SDI's (small diameter implants), as well as NDI's (narrow body implants). Although mini dental implant is actually a trade name for the most widely used small diameter implant, the 3M™ ESPE™ MDI Mini Dental Implant, the dental industry has adopted the term to describe this class of implants. Some small diameter implants are used as anchors in orthodontic cases and are called TADs, or temporary attachment devices. One example of a TAD is the Unitek™ Temporary Anchorage Device System. These differ from the more common mini dental implants in that they are removed after they are no longer needed and orthodontic treatment is completed.

Mini Dental Implants are constructed of various titanium alloys. The same applies to traditional implants.

Mini Dental Implant by 3M ESPE

Design

Currently, mini dental implants have a diameter of 1.8mm to 2.9mm and are offered in various lengths. It is important to note that the pull out strength of an implant has been shown to be based on its length rather than its diameter.^[3] Multiple tip, thread, body and head designs are available across the category as well. Most tip designs are sharp or slightly blunted to provide self tapping ability of the implant through the medullary bone. Some blunted designs taut a compression of the bone as an advantage. Thread designs vary from thin to thick and thread spacing is also variable. The design variations allow for use of the implants in the different densities of bone (D1-very dense, D2, and D3-soft) found throughout the mouth. The body connects the tip with the prosthetic head and can be a parallel sided cylinder or a progressively tapered cone. The aforementioned design elements contribute to enhancing initial stability. The choice depends again on the bone density encountered in the desired implant location. For one piece dental implants such the minis, the concept of initial (mechanical) stability is paramount for success. This is based on mechanical retention of the implant in the bone (See the osseointegration page), as well as the strength of the implant. There can be statistically significant differences in the strength of the implant. According to Binon, adequate mechanical characteristics are needed for an implant to resist functional occlusal loads.^[4]

The prosthetic head allows the dental prosthesis to connect to the implant and anchor it to the bone. It also connects to the implant driver during placement. Square, rectangular, or o-ball heads are common and connect easily to a simple set of corresponding drivers. Fixed crowns or bridges can be cemented directly to the square or cubic head of the mini. Subsequently, a sphere was milled into the square portion of the head allowing for a more elegant restorative solution. This ‘o-ball’ design became a popular solution to secure loose dentures. Other standard prosthetic options for removable and fixed solutions do exist and custom options are available from various dental labs.

Uses

Mini dental implants are extremely valuable for endentulous patients that have loose lower dentures and want an easy solution to secure them in place.^[5] Most denture patients have highly resorbed jawbones (Mandible and/or maxillary bones) and bone augmentation, aka bone graft, is required for a standard dental implant solution. Moreover, health status of many senior citizens contraindicates invasive dental treatment, such as a conventional implant. In contrast to conventional implants, a survey of 200 clinicians indicated that a flap procedure was mostly (80% of the time) unnecessary for placing MDI's.^[6] Healing time is decreased, as the ability to avoid flap surgery aids in healing (the periosteum is left undisturbed)^[7][8] and immediate satisfaction achieved with this minimally invasive approach. The shorter treatment time translates to lower costs as well; an important factor because implants are not typically covered by dental insurance programs.

Although not as widely utilized, many MDIs are FDA approved to be used for fixed crown and bridge installations as well.^[9][10] Proper case selection is critical but the available literature has demonstrated success that rivals standard implants. This means if you are missing a tooth or multiple teeth, a mini implant may be placed and a crown fabricated to cement on to the head of the implant.

Another important indication for Mini Dental Implants is the transitional stabilization indication. In this instance, Mini Dental Implants are used to give temporary support to the denture while the conventional implants and bone graft are healing.^[9]

Procedure

Mini dental implants are placed in a flapless and minimally invasive procedure under local anesthetic^[11][12]. This is in sharp contrast to conventional implants, which are often placed in a procedure requiring a flap, bone graft, and/or significant healing time^[13]. In the United States, using mini dental implants to secure a lower full denture is a generally accepted indication. A number of mini dental implants are placed in the mandible and these implants will be used to secure the denture (as opposed to adhesive materials or other methods of stabalizing the denture). For most types of mini dental implants, a small hole will need to be drilled before inserting the implant.

Pilot hole being drilled for Mini Dental Implants

Four Mini Dental Implants in mandible

See also

• Dental Implants
• Osseoincorporation
• Osseointegration
• Minimplants

References

1. ^ Griffitts, TM; Collins CP, Collins PC (2005). "Mini dental implants: An adjunct for retention, stability, and comfort for the endentulous patient.". Oral Surg Oral Med Oral Pathol Oral Radiol Endod 100: E81-84. 
2. ^ English, CE; Bohle GC (2003). "Diagnostic,k procedural, and clinical issues with the Sendax mini dental implants.". Compendium. supplement 1 24: 1–23. 
3. ^ Block, MS; Delgado A, Fontenot MG (1990). "The effect of diameter and length of hydroxyapatite-coated dental implants on ultimate pullout force in dog alveolar bone". Journal Oral Maxillofac Surgery 48: 174–178. 
4. ^ Binon, PP (1996). "The effect of implant/abutment hexagonal misfit on screw joint stability.". Int Journal of Prosthodontics 9: 149–160. 
5. ^ Shatkin, TE; Shatkin S, Oppenheimer BD, Oppenheimer AJ (2007). "Mini dental implants for long term fixed and removable prosthetics: A retrospective analysis of 2514 implants placed over a five year period.". Compendium 28: 36–41. 
6. ^ Christensen, GJ (2008). "Mini implants: Good or bad for long term service?". J Esthetic Dentistry 20: 343–348. 
7. ^ Gibney, JW (2001). "Minimally invasive implant surgery". J Oral Implantology 27: 73–76. 
8. ^ Campelo, LD; Camara JR (2002). "Flapless implant surgery: A 10 year clinical retrospective analysis.". Int Journal Maxillofac Implants 17: 271–276. 
9. ^ ^{a b} Ahn, M-R; An K-A, Choi J-H, Sohn D-S (2004). "Immediate loading with mini dental implants in the fully edentulous mandible.". Implant Dent 13: 367–372. 
10. ^ Mazor, Z; Steigmann M, Leshern R, Peleg M (2004). "Mini-implants to reconstruct missing teeth in severe ridge deficiency and small interdental space: A five year case series.". Implant Dentistry 12: 336–341. 
11. ^ Shatkin, TE; Shatkin S, Oppenheimer AJ (2007). "Mini dental implants for long term fixed and removeable prosthetics: A retrospective analysis of 2514 implants placed over a five year period.". Compendium 28: 36–41. 
12. ^ Christensen, GJ (2008). "Mini implants: Good or bad for long term service?". J Esthetic Dentistry 20: 343–348. 
13. ^ Sendax, VI (1996). "Mini-implants as adjuncts for transitional prostheses". Dental Implantol Update 7: 12–15.