1^st Consensus on Basal Implants

(Version 3, May 2015)

Due to the development of the surgical techniques and medical products and with regard to changes in the nomenclature, the International Implant Foundation has revised and updated the "Consensus on BOI" (Ver 1: 1999 Ver 2: 2006). This is hereby the 3rd consensus on basal implants provided for the specialist public. Copyright: International implant Foundation, Munich 2015.

Definition

Lateral basal jaw implants transfer the chewing force  on the cortical bone above and below one or more horizontal slices or rings.  According to this definition, basal screw implants (e.g. bi-cortical screws, BCS^®) also belong to the basal implants, if they are anchored in the 2nd or 3rd cortex and are introduced into resorption stabile bone areas.
Active biological osseointegration along the vertical axis of the implant is not necessary for the functioning of these implants.

This consensus concerns implants with completely polished/machined surface, even if combined implants are mentioned in this consensus.

Classification of basal implants

Authorisation/training/re-training

Generally even extensive experience with crestal implant systems (2-phase implants) is insufficient in order to be able to service basal implants. Therefore a product briefing (authorisation) and also re-training over years is required for the safe and optimal usage with these medical products.

Education

The training of basal implantologists shall be made only by authorised teachers with a valid certificate.

Expert evaluators

Evaluators, who have to assess the cases in which basal implants are involved (reimbursement cases, liability cases), must have a multi-year authorisation for basal implants, and be able to prove at least 50 fully completed treatment cases, 25 of which must be at least 5 years or older.

The preparation of the implant bed

Lateral basal implants

For lateral implants both turbine as well as fast-runner counter-angle pieces are applied. Also counter-angle pieces with 1:1 actuation can be used at with at least 25,000 RPM and good cooling. Contra-angle pieces with gear reduction of 1:10 or even 1:248 are unsuitable for the bone preparation for lateral basal implants.

Screwable basal implants and combination forms

Angled or straight contra-angle pieces are used in a cycle count of not less than 5000 RPM.
Any implantation is done under local disinfection, e.g. with Betadine^® 5%.

Combined with natural teeth and crestal implants

Basal implants have a constructive flexibility and can be used with stable teeth bridges. A disadvantage is the generally shorter lifetime of the used teeth   compared to the implants. Nonetheless, a combination of two-phase crestal implants is possible. The elasticity differences between lateral basal implants and crestal implants should, however, be pointed out. If such a combination is planned, there must be a rigid construction in the result in order to avoid overloading on rigid pillars.

Loading protocols and immediate loading

Lateral and crestal basal implants are generally used in immediate loading protocols. This means that the prosthetic splinting must be performed by the prosthetic design before the 3rd postoperative day.
For splinting, bridges with metal framework, direct laser welding and different veneers are used. Most recently composite frameworks without metal framework are applied. There are currently no long-term results available.

Where there is very little bone, immediate reconstruction is necessary even on the day of surgery.   In combination with compression screws and the presence of sufficient bone around the lateral basal implant, the prosthetic construction can be set with permanent cement no later than on the 5^th post-operative day.. In the distal portion of the upper jaw, the support should take place in the 3^rd cortex.

X-ray assessment implant loosening

Lateral and overload crestal basal implants in a so-called sterile loosening  . This condition is reversible,  as long as the overload is corrected in due time and the bony interface with the force transmission areas is not infected. In addition to assessing the individual implant, the prognosis and the statics of the overall design, the assessment of the previous course of treatment is also important.
Indications for the removal of screwable and lateral basal implants:

1. Radiographically there must be a sharply defined blackening around the basal disc or the entire apical thread of the implant.
2. Clinically:
   1. The implant is vertically moveable OR
   2. There are signs of a granulated inflammation around the implant.

There is no indication for removal when one of the following observations is made:

1. The bone around the basal plate is not radiographically affected by the blackening.
2. By the blackening only bone areas along the vertical implant units are affected.
3. Swelling and/or abscesses are present in the vestibular, lingual or palatal mucosa.
4. The implant hurts when biting, but there is no sharply defined blackening of the basal disc or the basal thread.
5. The presence of crater-shaped irruptions on the vertical implant sections.
6. Only parts of the bone around the discs show blackening in the X-ray
7. Only crestal discs are affected by the blackening
8. There is only one movement of the implant to the side. (cause of this movement can be, inter alia: (still) lack of integration of vertical implant sections; elasticity of the bone in the 2ndor 3rd cortex; possibly therapy-requiring reinforced remodelling in the area of the 2nd or 3rd cortex.)
9. Screwable basal implants can be rotated in the bone.