Dental Implant Placement: Principles and Considerations
Principles of Dental Implant Positioning: Anatomical Limitations
To maximize the probability of success, an implant should be placed entirely within the bone and away from significant anatomical structures. Ideally, there should be 10 mm of vertical bone dimension and 6 mm of horizontal dimension to place the implant. This size prevents the invasion of anatomical structures. There should also be adequate space between adjacent implants; usually, 3 mm is acceptable. This space is required to ensure the viability of the bone between the implants and allow for good oral hygiene. The anterior and posterior maxillary jaw and the posterior mandible require special considerations for implants. Once tooth loss occurs, resorption of the ridge follows a pattern that leads to the thinning of the bone crest. The consequences often cause problems in the anterior of both arches; irregular anatomy can cause problems in achieving ideal implant angulation.
Anterior Maxilla
There must be at least 1 mm of bone between the apex of the implant and the nasal vestibule. The anterior implants in the maxilla should be slightly away from the midline.
Posterior Maxilla
The bone is a less dense area than the posterior mandible. This may affect treatment planning, increase the required integration time, and increase the number of implants required. Typically, 6 months and a one-to-one implant-to-tooth replacement are required. The second problem in this area is the maxillary sinus. In the edentulous ridge close to the posterior maxilla, the surgeon should leave 1 mm of bone between the base of the sinus and the implant so that the latter can be apically anchored in cortical bone at the base of the sinus. If the bone is not suitable for implant placement and support, consider performing a sinus lift with bone grafting.
Implant Prosthesis
Implant Concept
A device, prosthesis, or substance that is placed on or in the body to improve some of its functions or for aesthetic purposes.
What are Implants? Dental implants are an alternative to conventional bridges or dentures to replace missing teeth. Today, dental implants are made of titanium or zirconium and placed by a surgical procedure in the mandible or maxilla. The implant acts as the root of the tooth to be replaced. They are usually placed at the dental clinic using local anesthesia, which can be supplemented with sedation. The postoperative period is usually not traumatic, and anti-inflammatory medication can provide relief.
Osseointegration
Osseointegration is the functional and structural connection between bone and the implant surface.
Healing
There are three major areas during healing:
- Alveolar Bone: Healing takes place after primary stability is obtained through an implant site that is consistent with the implant body. To this end, both the hardware and the provision of the surface and body shape of the implant play an important role.
- Supracrestal Fibrous Structure: Just like natural teeth, dentoalveolar and gingival fibers penetrate the cementum. Gingival coverage around the implant is an important factor for the adaptation of soft tissue in this region, where infectious reactions may occur.
- Epithelial Insertion: The mechanism of insertion of the regenerated epithelium, slightly adapted around the implant, plays a role similar to that of natural teeth and is the gateway for infection.
As an example of a simple implant system based on the principle of osseointegration, consider the ITI implant-Bonefit concept. In this system, the implant is a pierced body with the following features:
- Large surface area for implant retention.
- Small implant volume in the area of retention.
- Low bone loss during implant bed preparation.
- Implant stiffness similar to that of bone.
- Osseointegration promotes micro- and macro-retention.
- Decrease in tensions between the bone and the implant.
- Optimal bone biocompatibility.
- Standard instrumentation that is simple but high precision.