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 »  Home  »  Dental Implant 3  »  Computer Analysis of Titanium Implants in Atrophic Arch and Poor Quality Bone: A Case Report
Computer Analysis of Titanium Implants in Atrophic Arch and Poor Quality Bone: A Case Report
Materials and methods - Case Report.

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Rainer Bocklage, DMD, DUI
Private Practice, Dormagen, Germany.

The most important anatomic variables for implant placement are the maxillary sinus and the nasal fossa in the upper jaw and the mandibular nerve in the lower jaw. Inferior residual alveolar ridge height, insufficient bone volume, and poor bone density are the main reasons for inadequate insertion height of root-form implants. Initial stability cannot be achieved, making immediate implant loading impossible. Under these difficult conditions in atrophic jaws, osseointegration of implants is often prevented after osteolysis and implant loss. To avoid bone grafting or other surgical bone augmentation procedures, the lateral insertion technique is preferable in these cases.
In the clinical case presented herein, all implants (maxilla and mandible) were placed in a single surgery session under general anesthesia and immediately loaded with fixed esthetic temporaries. Using SIM/Plant images (Columbia Scientific, Columbia, MD), the osseointegration of these titanium fixtures is visualized four years after implantation. These images impressively demonstrate the positions of implant sites relative to the maxillary sinus, the nasal fossa, and the mandibular nerve.

MATERIALS AND METHODS.
For difficult implant cases, such as the extremely resorbed jaw and type IV bone, lateral implantation surgery is a particular alternative for the achievement of initial stability and osseointegration. The procedure is minimally invasive and free of bone grafting or other augmentation techniques. Regarding a residual ridge height of _5 mm, this osteotomy is microsurgical. Lateral osteotomy disk-design implants are placed. They comprise an implant shaft with threads and one or several basic disks. The loading transmission bone-to-implant interface is shifted to the whole arch width by anchoring the disks from the outside cortical bone to the inside cortical bone (outside laminar bone to inside laminar bone in class IV bone). A considerable increase in the bone-contact area and excellent immediate stability for diskdesign implants is achieved by using the full jaw width.7 It is important to mention that the shaft of this particular implant is only the connecting component for prosthetic abutments. The supporting bone formation around the implants is changed from the vertical to the horizontal plane by inserting diskdesign implants. Vertical osseointegration is a major determinant of root-form implant success. Horizontal osseointegration is more important for laterally inserted implants. There are also significant differences in biomechanics and bone healing. Applying the lateral insertion technique, a primary bone healing can be shown in the area around the disks. Bone repair is possible without the formation of callous tissue in this particular area of the implant. Therefore, immediate functional loading for this implant form is physiologic. SIM/Plant software was used for better visualization of the bone-to-implant interface. The software is actually a preoperative planning tool for dental implant placement. A radiologist makes a dental CT scan of the arches. A template is placed in the patient’s mouth during the CT procedure. The CT data must then be reformatted into panoramic and cross-sectional images by a SIM/Plant workstation. This software makes it possible to work with pseudo-color scales—a very illustrative technique. The different colors (within each hue, the luminance varies from dark to light) represent the different CT densities of the soft tissues and the bone tissue. A reformatted CT study consists of an alignment image, an axial image, and a panoramic image of each arch with the corresponding cross-sectional images. Implant ossification and the anatomical structures near the implant sites are clearly described with this image technique.

CASE REPORT.
The edentulous maxilla and the almost edentulous mandible were treated under general anesthesia in a single surgery session (Figs. 1–4). Implant placement in the posterior areas of the jaw is essential to the realization of an adequate loading of fixed restorations onto the implants. The number of fixtures was minimized to not impede the vascularization of bone and to avoid a huge number of foreign materials in the jaw. Seven days after surgery, the implants were immediately loaded with fixed esthetic temporaries (metal/resin). Disk-design implant placement causes primary bone healing in the area around the disks; therefore, the definitive restorations could be fabricated according to the gnathologic crown and bridgework technique 40 days after the procedure. Four years after implantation, the implant bridgework is still functioning (Fig. 5).

Fig. 1. An initial panoramic radiograph that shows an extremely   resorbed edentulous maxilla and a nearly edentulous mandible with a severely   atrophic jaw in the right and left posterior areas.
Fig. 2. A panoramic radiograph after the placement of nine disk-design   implants in a single surgery session.
Fig. 3. A Scanora (Soredex, Helsinki, Finland) radiograph of the left   posterior maxilla after placement showing a multicortically anchored double   disk-design implant.
Fig. 4. A Scanora radiograph taken after placement in the area of the   tooth 47. It reveals a mono disk implant. Its bone support is tricortical.

An initial panoramic radiograph that shows an extremely   resorbed edentulous maxilla and a nearly edentulous mandible with a severely   atrophic jaw in the right and left posterior areas