Slide 1: CHAPTER 69 CLINICAL ASPECTS OF DENTAL IMPLANTS Branemark presented his research for the first time in North America after working since 1960 on titanium implants and osseointegration at the conference held in Toronto, Ontario, Canada in 1982. His findings were unanimously considered a breakthrough in dental prosthesis and oral rehabilitation and the opening of a new era in clinical dentistry. Since the mid 1980s, clinical and laboratory research in dental implantology has resulted in the development of numerous implant must be : Sterile. Made of highly biocompatible material such as titanium. Inserted with an atraumatic surgical technique that avoid overheating of the bone during the preparation of the recipient site. Placed with initial stability. Not functionally loaded during the healing period of 4- 6months. Slide 2: DENTAL IMPLANT Slide 3: DENTAL IMPLANT. RADIOGRAPHIC APPEARANCE OF IMPLANT. Slide 4: INDICATIONS AND CONTRAINDICATIONS : Patients with partially or fully edentulous arches may be considered for dental implants. Individuals who are unable to wear removable dentures and have adequate bone for insertion of an implant are good candidates, provided they are in good general health and are able to maintain good oral hygiene. Uncontrolled diabetes, prolonged steroid therapy, radiation therapy and abuse of alcohol and smoking may contribute to the failure of the implants. Presence of periodontal disease is also considered to be a contraindication for dental implant placement. Patients who failed to maintain plaque control are poor candidates for implant therapy. Traditionally implants are done after the healing of the extraction wounds. Sometimes implant placement immediately after extraction may also be done if : Socket walls have sufficient residual bone walls. Socket must be free of pathosis. Slide 5: The soft tissue available should allow primary closure. Apical to the socket, a sufficient volume of bone must be available for stabilization of the implant. SELECTION OF CASES AND PREOPERATIVE DIAGNOSIS : It is important to analyse the anatomy of the maxillofacial and intraoral region via clinical and radiographic examinations before the implant surgery. The preoperative diagnosis is necessary to predict the amount of bone available for implant placement and to evaluate presurgically whether the patient is a suitable candidate for implant treatment. Clinical examination of the jaw bone consists of palpation and probing through the soft tissues (intraoral bone mapping) to assess the thickness of the soft tissues at the proposed surgical site. The periapical and panoramic views are taken. The orthopantomograph allows a more comprehensive view of mandible and maxilla. Slide 6: In the totally edentulous, the lateral cephalometric view is very beneficial, especially in the mandible, because it shows angulation, thickness and vertical bone height. With newer diagnostic techniques such as conventional linear tomograms and computed tomographic (CT) scans, it is possible to go beyond the standard two- dimensional radiographs. Exact cross- sectional (three dimensional) radiographic views of residual bone are possible via specialised software programmes. This technology is costly and has increased risk for radiation, but it allows a more predictable diagnosis, since it demonstrates whether there is inadequate height and width of bone and the location of vital anatomic structures. VARIOUS IMPLANT SYSTEM : Several implant systems are used for tooth replacement. These differ mainly in biomaterial, design and surgical procedure. The four most often used biomaterials are commercially pure titanium, micro- enhanced pure titanium, plasma- sprayed titanium surfaces and plasma sprayed hydroxyapatite surfaces. Slide 7: The three main implant designs are : Screw- shaped implant form. cylinder shaped form. Tapered screw- shaped form. Surgical procedures can be performed in two stage or in one stage. a) TWO- STAGE PROCEDURE : The first operation is for implant insertion and the second operation several months later, is for uncovering the implant and attaching a prosthetic abutment. b) ONE- STAGE PROCEDURE : Implants are inserted and left exposed to the oral environment, they are not loaded, however,during the healing period. Most implant system offer a variety of implant lengths (7 to 20mm)and width (3.2 to 6mm) to accommodate the available bone quantity. In addition, they include an internally or externally irrigated precision drill set, as well as precisely matched components for surgical and prosthetic needs. More than 50 different types of implants are available worldwide. Slide 8: NOBLE BIOCARE SYSTEM : The Branemark system in early 1960s, consists of a screw- shaped dental implant, made of commercially pure titanium and applied in a two- stage surgical procedure . The relationship of the implant to the bone at the light microscope level is by osseointegration . Recently a new surface treatment to the implant has been added by increasing the thickness of the oxide layer (Ti- unite). The Steri- Oss system is part of the Nobel Biocare system. A tapered titanium screw is most used implant of this system, which comes in an acid etched, TPS and HA coating. INTERNATIONAL TEAM FOR ORAL IMPLANTOLOGY (ITI) SYSTEM : Schroder and colleagues used one- stage implants and called this functional ankylosis. The ITI implant system uses different design from original hollow cylinder to a full- body screw design. The initial plasma sprayed titanium coating has changed in the recent years to a sand- blasted, acid etched surface. Slide 9: Because this implant system protrudes through the mucosa from the day of insertion, it does not require a second intervention, but there is an increased risk of premature loading during the healing period and the danger of titanium showing in the marginal mucosa area. 3i (IMPLANT INNOVATIONS) SYSTEM : The 3i implant system was developed by Lazarra and Beaty in 1988. It is based on Branemark system and includes a two- stage commercially pure titanium screw and cylinder with either an acid- etched, a plasma- sprayed hydroxyapatite (HA) coated surface. Recently one- stage implant was introduced which is largely based on Schroeder system. ASTRA DENTAL IMPLANT SYSTEM : Developed in 1980s, in Sweden. It consists of a self- tapping screw made of pure titanium and is characterized by a conical abutment that fits tightly into the coronal part of the implant. The system has a titanium oxide- blasted surface and a special single tooth implant with a wider microthreaded, tapered collar. Slide 10: The screw shaped titanium implants are presented with a titanium- oxide- blasted coating. OTHER SYSTEMS : The Paragon / Core- vent system, Integral system, IMZ system, Frident system and the TPS system. Other variety of implant designs offers from screw- shaped to cylinder types, as well as implant surface characteristics from machined pure titanium to HA to plasma- sprayed titanium coatings. IMPLANT RECONSTRUCTION AND AESTHETICS : The patient who seem to benefit from dental implants are those with fully edentulous arches. The original design of the edentulous arch was a fixed bone- anchored bridge that used five to six implants in the anterior area of the mandible or maxilla and a cantilever through the premolar area. Most implant bridges currently used are screwed into place and can easily be removed by loosening the fixation screws, which increases the overall comfort and reliability for the patient. Slide 11: DIFFERENT IMPLANT DESIGNS IMZ. BRANEMARK (noblepharma). INTEGRAL- HYDROYAPATITE. Slide 12: Another treatment option for the rehabilitation of an edentulous arch is the overdenture retained by clips to a bar splinting two to six implants and far superior to conventional complete dentures. Partially edentulous patients with single or multiple missing teeth are ideal for osseointegrated implants. Osseointegrated implants can support a free standing fixed partial prosthesis. Adjacent natural teeth with are not necessary for additional support. The major advantage of implant- supported restorations in partially edentulous span has two major advantages : Preparation of adjacent abutment teeth is not required. Larger edentulous spans can be restored with fixed bridges. Slide 13: SINGLE TOOTH REPLACEMENT : 1. The replacement of single missing teeth with implants has two major advantages : Preparation of adjacent teeth is not required. The ridge will be maintained by implant. The primary candidates for single tooth implants are all anterior teeth from central incisor to second premolar in the maxilla and mandible provided that no lateral forces are induced by single standing implant. Molar replacements with single implants are less indicated, owing to the high stresses generated in the posterior region of the mouth and the insufficient force distribution over one implant, leading to potential bone resorption. COMPLICATIONS : Less than 10% of implants will show some form of complication over the life of the implant. Can be detected during the treatment phase (early onset) and / or during the maintenance phase (late onset). When a dental implant demonstrates any degree of mobility after the healing period, it is considered a failure. Slide 14: When this mobility suggests a fibrous connective tissue interface, that does not function well over time, implant must be removed. After an appropriate healing time, it is possible to place another implant. During the maintenance phase, once osseointegration is established complications can be divided into : Adverse tissue reactions such as mucosal inflammation. Progressive bone loss. Mechanical problems such as component fractures or screw loosenings. MAINTENANCE PHASE : Proper oral hygiene and appropriate occlusal forces are critical for long- term function of an implant. Poor oral hygiene and occlusal trauma have been related to marginal bone loss control. Plaque control should be started immediately after the implant is exposed to the intraoral environment and monitored overtime. Recall visits in 3-month intervals for the first year and then on semiannual basis. Recall visits include evaluation of oral hygiene, occlusal harmony, implant and prosthesis stability, overall soft and hard periimplant tissue health, and radiographic follow- up. Slide 15: SINGLE TOOTH REPLACEMENT IMPLANT IN PLACE. METALLOCERAMIC CROWN. CLOSE- UP VIEW.