Chapter 27 Implantology
Age - the age of a patient has not shown to have an effect on the success or failure of implants
Systemic conditions - implants may not be an option for patients with systemic conditions
HIV/AIDS:
Uncontrolled diabetes
Anything that will decrease immune function
Social Risk factors can also effect the success of implants. Patients with certain lifestyle choices are not good candidates for implant surgery
Smoking
excessive alcohol intake
drug abuse
stress
Consultation with patient's physician is required if a patient has blood-coagulation disturbances, is on long-term steroids, or has cancer that requires chemotherapy
Components of an implant:
Implant body or fixture which is surgically placed into the bone
The abutment (metal post) is the part that is attached to the implant body and will be fitted with a restoration that can be placed on top of it
The superstructure is the prosthetic replacement that is either screwed or cemented to the abutment
Types of implants: implant success and survival rates are affected by the anatomic region of the jaw, the quality of the bone, and the length and width of the implant. Minimal criteria for a successful implant should include absence of clinical mobility absence of persistent and/or irreversible signs and symptoms of pain or infections, no peri-implant radiolucency, no irreversible mechanical failures
Endosseous implants: shapes include blade, cylinder, and screw types with each manufacturer having its own designs
Most commonly used implant
Placed in edentulos areas of maxilla or mandible
Osseointegration: describes the direct contact of a load-carrying dental implant with bone without any intervening connective tissue. The implant becomes a part of the bone
Subperiosteal implants: "under the periosteum" These implants sit on the bone and under the periosteum and gingiva
Transosteal implants: "through the bone" These are mandibular denture anchors placed all the way through the mandible and usually has five to seven pins. Great success rate but complications are more common
Transitional implants: "mini implants" these implants have a machine or treated surface. They have been used in orthodontic anchorage and for prosthetic rehabilitation
Endotontic implants: "in and through the tooth" Also called endodontic stabilizers. Not common in U.S. due to its poor prognosis
Surgical procedure
Two stage procedure: First stage bone is drilled and implant is positioned. implants are allowed to heal for 3-6 months for osseointegration Second stage: uncovering the implant to replace the cover screw with a temporary healing abutment or post that screws into the implant fixture :
Single-stage: implants placed with primary stability can be put into function immediately as long as the forces are controlled
Implant Vs teeth:
Anatomy: natural teeth are surrounded by periodontium, implants are surrounded by perio-implant tissues including osseointegrated bone surrounding the fixture and no periodontal ligament
Implants have a perimucosal seal that adheres to the implant and has similar biologic features to the epithelial-tooth interface of a natural tooth. There is no cementum and no connective tissue
Blood supply: implants have less blood supply near their neck with more of a scar tissue appearance
Plaque: plaque has been shown to grow faster on titanium than on enamel which results in widespread inflammation around the implants
Bacteriology: neither implants or natural teeth are immune to plaque. Studies have shown that there are no differences in the amount of plaque or the type of bacteria that accumulate on teeth or various implant surfaces.
Peri-implant disease: has many of the same clinical manifestations and stages as periodontitis and is characterized by rapid loss of bone that can occur without any classic sings of pain or mobility
Graded from slight to severe, Light can be treated with improved oral hygiene, severe may require surgery
Instruments for implants: Most implant surfaces are titanium which is easily scratch able so instruments that clean implants should be made of plastic or other non-metallic materials. Air-powder abrasive units are effective but should not be used directly on implant components for any length of time
Clinical assessment of an implat is similar to natural teeth: gingival consistency , color, presence of inflammation
Blade, screw, cylinder
This type of implant is not used frequently except if there is insufficient bone mass for a root-type implant that cannot be corrected with surgery
Has a great success record and works well for patients with severe mandibular bone resorption
They have less than 3mm, their main advantages are that they provide retention, stability, and support of the prosthesis, better chewing and phonetics for the patient, and protection of an augmentation site as well as a vertical stop
Preoperative steps: a full workup on the patient( study models, wax-up of the planned restoration, fabrication of a radiographic and surgical guide stent, x-rays. Evaluation of bone quality as well.
Immediate implant placement in extraction sockets - implants can be placed at time of extraction, drawbacks to this type of surgery inclue protracted healing time, excessive pain, and swelling and a large ridge defect if the implant fails and has to be removed
Guided bone regeneration is a surgical procedure performed to increase the amount of alveolar bone available for the proper placement of a dental implant. involves the formation of bone, cementum, and periodontal ligament around teeth and not just bone.
Sinus grafts are needed sometimes to increase the height of the posterior alveolus.