24 Theories and techniques of oral implantology

fit is very tight, the overlying tissue may be sutured over it (Fig. 1-62), or three small Vitallium screws can be used to secure the implant. These are used only to establish primary retention for the implant, since the fibrotnucosal tissue will soon tenaciously bind itself in and around the meshwork of the sub-structure that is in direct contact with the osseous tissues.

Suturing should be done by making a mattress suture around each protruding post and closing the remainder of the tissue with interrupted sutures. Enough sutures should be made so that no blood can be seen oozing between the approximated segments. The sutures should also be tight rather than loose.

Immediately after the tissues have been sutured, the original or a new prefabricated denture with acrylic teeth should be fitted into place over the four abutments. If a new denture has been fabricated, little adjustment is necessary. However, if one of the original dentures of the patient is to be used, it must first be thoroughly hollowed out on its tissue-bearing surface, tried in the mouth, and balanced. The denture should not be in premature occlusion; the bite should not be opened beyond the original opening. The denture should be hollowed out until the bite seems natural to the patient and to the dentist. Then fast-setting acrylic is mixed and placed inside the hollowed-out portion of the denture. The denture is placed into its proper position over the four implant abutments, and the patient is guided to bite into centric occlusion.

It is imperative to remove the denture long be-fore the acrylic sets, because excess acrylic can slip underneath the abutments to the narrower undercut necks, preventing removal of the denture. Therefore a good procedure is to remove and replace the denture every 20 seconds or so during the setting of the acrylic. As soon as the acrylic starts to get hard, it should be left outside the mouth to set. All excess is then trimmed away and polished to a smooth consistency. In this manner no complications occur. Never should the denture be tissue-bearing. There should be a slight space between the implant and tissue contacting only the four parts.

Final visits. In about 3 to 6 weeks the implant will have completely set and the surrounding tissues will have sufficiently healed (Fig. 1-63). At this time, the final "pick-up" impression for the final implant prosthesis can be taken.

The superstructure framework is first placed over the four implant abutments (Fig. 1-64), and an accurate wax or stone bite is taken (Fig. 1-65). The

Fig. 1-61. The site is again exposed and the implant fitted over the exposed bone. The implant should fit flush with the bone.

Fig. 1-62. With the implant in place, the tissues are sutured over it.

Fig. 1-63. Condition around the posts 3 weeks after the insertion of implant. Notice that the tissues have healed nicely around the posts and are in excellent health.