Stage Two Implant Surgery

Delayed Loading Implant Exposure
The philosophy that has been described has its main objectives in the predictable achievement of osseointegration and the creation of an adequate hard - tissue foundation to provide support for the soft-tissues. It is intended that sufficient soft tissues in bulk and contour are present to facilitate the development of the desired harmonious emergence profile.It is the shape of the component part, which is attached at the time of exposure,that influences the emergence profile. It is therefore obvious that the size and the shape of the component part used should closely match the final abutment and restoration.

Healing abutments are conventionally used at this stage. These are cylindrical components which are available in different heights and diameters to suit the softtissue thickness of the particular patient and the diameter of the implant used. A periapical radiograph gives an indication of the soft tissue thickness and the apico-coronal placement of the implant, thus helping in selection. The usual heights of healing abutments range from 2 to 5 mm. It is essential that the soft tissue does not overly the healing abutment after they are secured in place.

Upon surgical exposure either by raising a flap or using a tissue punch, the cover screw is loosened and removed and the healing abutment is attached to the implant, followed by suturing around the healing abutment with interrupted suture(when flap is raised).The disadvantage with healing abutments is that they are cylindrical in shape and the emergence profile created is not exactly the same that would be with the final prosthesis(Especially in fixed implant supported prosthesis). It is often observed that at the cementation appointment when the healing abutment is replaced with the final abutment and the crown is placed, there is a resistance by the soft tissue collar to complete seating of the prosthesis (as Healing abutments are generally narrower that the posterior crowns). In the anteriors where the crowns are slightly triangular in cross section (Palatal/ lingual convergence), the mismatch with the cylindrical profile created (by healing abutment) leads to less than ideal aesthetics.

Healing abutment

Healing abutments are therefore not considered ideal. It is for this reason that the definitive abutment, selected at first stage surgery, is considered to be ideal for attachment at this stage.This enables the abutment that is ideally shaped for the proposed restoration to be connected at the time of implant exposure. Attachment of the definitive abutment at this stage of treatment prevents the repeated disconnection and reconnection of component parts. This has several benefits:

•  It prevents excessive negative tissue reactions associated with repeated disconnection and reconnection.
•  It avoids inaccuracies that are associated with repeated transfers of component parts between the surgery and laboratory.
•  It reduces costs by avoiding the purchase of component parts required for transfer of information and additional laboratory procedures.

Furthermore, a transitional restoration fabricated from impressions taken at first - stage surgery may also be contoured and fitted at this stage.Attention needs to be paid in particular to implants requiring restorations with abutment angles greater than 15 o .The types of incision described in the procedure are used to gain access to the implant, are designed to allow the creation of a natural papillary and marginal contour consistent with the adjacent teeth. The aim of the protocol is to simplify the treatment for patient, clinician and dental technician.