Chapter 2 The Basic Insertion and Reconstructive Protocol Guidelines
Step by Step
After making a minimal starter drill opening directly through attached crestal gingiva, then use a 1.1-mm bone drill through dense crestal cortical bone and drill farther into the more porous medullary bone, and terminate drilling in denser basal bone found typically in mandibular symphysis or posterior dense basal bone layers close to buccal-lingual cortices, buccal external oblique ridges, and lingual mylohyoid ridges. In the maxilla, apical terminus locations should end in the floor of the nasal cavity, floor and bony septa of the antra, cortical walls of the tuberosities, sinuses, pyriform rim, and nasal cavity. Dense midline suture bone may also be a useful destination for apical termination, providing a solid bite-in surface for the apical tip of the mini dental implants (MDIs). Bicortical stabilization is the essential principle.
A standard width 1.8-mm MDI with O-Ball Head or rectangular head (sometimes referred to as square head) abutment should be the most useful size for exploration of bone density, quality, and supportiveness during function and/or parafunction. Wider-threaded MDIs can be employed if a greater “bite-in” is needed than can be provided by the ultra-narrow standard 1.8-mm MDI. One can always change from the 1.8-mm standard MDI to a wider type, using the same starter opening without stripping bone, but not vice versa because the 1.8-mm implant will no longer be in sufficient oppositional contact with mature unprepared bone and consequently will be less likely to be useful as a long-term supportive implant.
Mini implants that are narrower than 1.8 mm typically used in orthodontic TAD applications will not be in immediate contact with enough bone to qualify as anything more than the transitional anchorage for which they were originally designed and dedicated (see Chapter 9).
The wider the mini implant the greater the challenge for that implant to be immediately and sufficiently bone-appositioned for predictable functionality without observing the gradual healing delay once considered essential for classic Branemark-defined osseointegration to occur. As a direct consequence of this working rule of thumb, it is suggested that the surgeon routinely start by inserting a standard 1.8-mm width MDI, the slowly-evolved optimal diameter derived during the early clinical trials period by Sendax, Balkin, and Ricciardi, and an exploratory technique to determine the bone quality and quantity in the placement site before actually inserting the MDI into its final desired location.
Only after this initial step using the 1.8 mm width mini implant should one proceed to try wider diameter 2.1 to 2.5 mm examples in hopes of gaining increased osseous surface area stability and functional supportiveness in Type IV bone sites of poor density and trabeculation.
Another advantage of starting the procedure with the standard width 1.8-mm MDI is the conservation of bone achieved by only gradually “upping the ante” with increasing width implants. The simple but essential choice of osteotomy avoidance with the narrower diameter mini will go a significant way towards avoiding undue loss of valuable bone resource during the critical osseoapposition insertion process.
Nothing presented herein is considered technically “set in stone” because operational variations in MDI pedagogy and training continually evolve with experiential outcomes being gleaned from broad-based clinical settings and from ongoing feedback from laboratory, industry, and research domains. Representative examples are to be found throughout this textbook, some with considerable modifications from this core presentation.