Mandibular endosseous implant interventions 355

Fig. 9-71. The superstructures are cemented over the templates with a soft cement.

Fig. 9-72. Lateral plate x-ray revealing screws going through template.

Fig. 9-72 shows the three vent-plants and the template with its set screws connecting the template to the implants. Fig. 9-73 illustrates the bridges over the template.

BILATERAL RESTORATIONS

When inserting implants in a mandible where both posterior quadrants of teeth are missing, the same basic steps are taken as for a unilateral free-end saddle bridge. However, it must first be deter-mined whether both bridges are to be fabricated

Fig. 9-73. Lateral plate roentgenogram showing superstructures in position

independently or whether they will be incorporated into one complete full arch splint.

A number of factors can influence the operator's decision :

1. Whether or not both bicuspids on each side of the arch are present can aid in the determination. If no bicuspids, or only one on each side, are available, then a full arch splint should be used.

2. If both bicuspids are present in each quad-rant, the density of the bone surrounding them and the condition of their periodontal attachments should be evaluated. If the bone has resorbed a good deal and the teeth are mobile, then a full arch splint should again be chosen.

3. The condition of the anterior teeth should be considered. The absence of decay and the lack of fillings should certainly influence the operator, as well as the patient, as to the diagnosis of two independent fixed partial dentures instead of a full arch prosthesis.

4. If the maxillary arch contains a full complement of teeth, a full arch fixed lower prosthesis might be considered. However, the presence of a full or a partial maxillary denture may indicate unilateral splints for the mandible.

5. The absence or presence of bruxism and other adverse habits such as pipe smoking should be taken into consideration.

6. The height, thickness, and density of the osseous structures in the edentulous areas affect the choice. The less ideal the site, the more effective a full mouth splint.