IMPLANTOLOGY

1. IMPLANTOLOGY DR MAYANK SAXENA MDS, ORAL & MAXILLOFACIAL SURGERY SENIOR LECTURER MAHARANA PRATAP DENTAL COLLEGE KANPUR

2. IMPLANTOLOGY DEFINITION : Dental implantology is a new branch of dentistry which involves the reconstruction of missing teeth and their supporting structures with natural or synthetic (alloplastic, allogenic or autogenous) substitutes. WHAT IS A DENTAL IMPLANT? Dental implant is an artificial titanium fixture (similar to those used in orthopaedics) which is placed surgically into the jaw bone to substitute for a missing tooth and its root(s).

3. PHILOSOPHY A natural tooth consists of a crown (the part above the gum), and the root (the part hidden under the gum). It is the root in the jawbone that actually holds the natural tooth in place.�A dental implant is a small man-made titanium fixture that serves as a replacement for the root portion of a missing natural tooth. Titanium is used because it is the most compatible with human body. The dental implant is placed in the bone of the upper or lower jaw and functions as an anchor for the replacement tooth. After the bone has grown around the implant, implants can hold a crown, bridge or overdenture just like roots hold natural teeth in place. Implants provide additional support where teeth are missing without putting forces onto remaining natural teeth. They may be used to support the replacement of a single missing tooth or a complete functional set for individuals who have lost many or all of their teeth.

4. CLASSIFICATION OF DENTAL IMPLANTS Dental implants may be classified by A) BY GENERAL SHAPE OF IMPLANT Type as endosseous, subperiosteal, transosteal, intramucosal, endodontic, and bone substitutes. These implant types are subdivided as follows: Endosseous: Root form. Blade (plate) form. Ramus frame. Subperiosteal: Complete. Unilateral. Circumferential. Transosteal: Staple. Single pin. Multiple pin

5. B) Implant Types - Prosthetic Attachment 1. External Hex 2. Internal Hex 3. Internal Taper 4. spline C) Implant Surfaces - Speeding Integration Basic Implant Design: 1. Threaded 2. Non-Threaded (Cylinders) Specific Micro-Surface Design: 3. Machined 4. Acid Etch 5. Shot Blasted 6. Titanium Plasma Spray 7. Hydroxy Apatite (HA) Plasma Spray 8. Porous Sintered Surfaces Pure titanium vs Titanium Alloy

6. D) Implant Technique 1. One Stage 2. Two Stage 3. Immediate Load 4. Immediate placement E) According to the bio-materials used to make Implants: METALS & ALLOYS Titanium 2. Titanium Aluminum vanadium 3. Cobalt chromium molybladium 3. Iron-chromium-nickel CERAMIC AND CARBONS Aluminum oxide Hydroxyapatite Tricalcium phosphate Carbon Carbon silicon POLYMERS Polymethyl methacrylate Poly tetra fluoroethyene Poly ethylene Poly sulfane Commercially pure titanium is the most commonly used material.

9. Indications of Implants 1. Edentulous patient. 2. Partially edentulous patient with history of difficulty in wearing RPD. 3. Patient with missing dentition requiring long span FPD treatment. 4. Patient who refuses using RPD. 5. Poor oral muscular coordination. 6. Parafunctional habits that compromise prosthesis quality. 7. Unrealistic patient expectations for complete dentures. 8. Hyperactive gag reflex. 9. Unfavorable number & location of abutments 10. Single tooth loss,to avoid preparation of sound teeth..

10. Contraindications of Implants Absolute 1. High dose irradiated patients. 2. Patients with psychiatric problems. 3. Haematologic system disorder patients. Relative Pathology of hard/soft tissues. Recent extraction sites. Patient with drug, tobacco, alcohol abuse. Low dose irradiated patients. Collagen/connective tissue deficiency.

11. ADVANTAGES As our life span increases, a permanent dental replacement like implants is increasingly important as we get older. While dentures and removable bridges are usually loose and unstable, Implants provide you with dental replacements that are both natural looking and very functional. Implants look much better, and feel better, than traditional removable bridges, Implant offer the same force for biting as bridges that are fixed in place. Implants will last your lifetime.

12. DISADVANTAGES Implants are a major investment and not without risk. The extensive use of implants can cost tens of thousands of rupees to achieve a great result. It is also a very time consuming procedure when having many implants placed. As this procedure is surgery, it is very important to research and find a well credited cosmetic dentist that you are comfortable with. For some people there are varying degrees discomfort or pain, which subsides in a couple of days. As with similar types of surgery, bruising and minor swelling might also develop shortly after the procedure. The crown (false tooth placed on top) will need to be replaced in ten to fifteen years.

14. OSSEOINTEGRATION Definition of Osseointegration�� Osseointegration was originally defined as a direct structural and functional connection between ordered living bone and the surface of a load-carrying implant. It is now said that an implant is regarded as osseointegrated when there is no progressive relative movement between the implant and the bone with which it has direct contact. In practice, this means that in osseointegration there is an anchorage mechanism whereby nonvital components can be reliably and predictably incorporated into living bone and that this anchorage can persist under all normal conditions of loading.

19. Stages of Dental Implant Treatment Step 1: Examination and PlanningStep 2: Placing the Dental Implant OsseointegrationStep 3: Connecting the Abutment and Conversion ProsthesisStep 4: Restoration

22. PROTOCOL Step 1:Examination and Diagnosis consist of an oral examination, full-mouth x-rays, panorex x-rays, diagnostic casts and photographs. It should be done less than six months prior to surgery.Step 2:- Stage 1 Surgery- Implants are placed in jaw.- Swelling disappears 4 to 7 days after surgery.- Sutures are removed 7 to 10 days following surgery.- A soft diet is recommended during the first 4 to 6 weeks.- Osseointegration occurs in 3 to 6 months.- Example of upper and lower complete tissue integrated prosthesis supported by osseointegrated Br�nemark dental implants during casting try-in procedure.Step 3:- Stage 2 Surgery -- Implants are uncovered.- Implants are checked for osseointegration.

23. - Abutments are placed.- X-rays are taken.- Impression of mouth is done for the final prosthesis.- Casting try-in procedure is completed.- Conversion Prosthesis is made.- Sutures are removed 7 to 10 days later. Step 4:- Tissue Integrated Prosthesis is completed and placed onto the implants.- Final adjustments are made.- X-rays are taken.Follow Up Care:Oral hygiene maintenance is performed at 3 to 6 month intervals following placement of the final prosthesis. Regular and fastidious oral hygiene maintenance is the key to the long-term success of dental implants.

24. TWO STAGE ENDOSSEOUS IMPLANT SURGERY Stage � I surgical technique Flap design & Incision: The incision may made into two way ? remote or crystal. The remote incision is made away from the implant site, usually 1-2mm interior to the mucogingival junction. Full thickness mucoperiosteal flap is elevated with periosteal elevator. The advantage ? the implant is fully covered with out suture over its top. It preferred in case of extensive bone augmentation For the crestal design flap, the incision is made along the crest of the ridge bisecting the existing zone of keratinized mucosa. Advantages � less bleeding easier flap management less vestibular changes post-up faster healing The incision should be made in one pass through the mucosa and periosteoum and healthy score periosteoum areas of soft tissue invagination into prior extraction sockets are excised so as to create a clean margin for the flap devoid of epithelium.

25. Flap Elevation: Full thickness flap are elevated buccally & lingually up to level of the mucogingival junction. In case bone augmentation procedure is planned the flap can be extended by making a partial thickness flap beyond the mucogingival line. This helps to approximate the margins of the flap without tension after the augmentation. Implant site location: A surgical stent that needs to be fabricated during the planning stage is placed intra-orally and through it small round bur as spiral drill may be used to mark the implant site. The stent helps determining the faciolingual location and ideal angulations for the implant. Ideal angulations is perpendicular to the occlusal plane and corresponds to the cingulum of the teeth for screw retained bar or prosthesis or incisal edge for cement retained fixed prosthesis

26. Implant site preparation: A small 2m diameter spiral depth and align the axis of the implant site. The center implant site is prepared first. The angulations is checked again in a labiolingual direction with the template and in a mesio-distal direction with the help of an assistant standing over the midline at foot of the chair. Factors critical to minimal heat during osteotomy preparation Cooling fluid � the drill may be externally or internally integrated with copious amounts of cooling fluid. Minimum volume of bone removed by each drill i.e. there should be slight incremental drill diameter with every charge of drill. Drill sharpness and design � New drills with sharp cutting edges maximize efficiency blade angulations & number also determine amount of bone engaged. Frequency / time of contact: A pumping motion is used to prepare site, less the frequency of contact less the heat generated. Pressure: Minimal pressure should be applied. Speed: The spiral drill is used at 800 to 1000 rpm and as we graduate to larger diameter drills the speed is reduced to about 500 rpm.

27. The length of the implant must be selected taking into consideration any reduction in bone height during ridge preparation. The relationship to vital structures may be cross checked at this stage In case of multiple implants a paralleling or direction indicating pin should be used to align subsequent implant The implants should be at least 3mm apart to ensure room for oral hygiene maintenance around the final prosthesis. Next step is to enlarge the site to that of the selected implant using a series of drills. A critical step in obtaining rigid osseous fixation after initial implant is to maintain a rigid bone � to � implant interface without micro-movement between the time of original placement and the second stage surgery. For that the final diameter drilling should be done with a steady hand, applying constant pressure & direction without cobbling to obtain a precise round osteotomy. In certain situation the higher implant is placed above the bone the greater risk factor trauma that may result in movement of the interface during initial healing on other hand if implant�s crest module was placed below the crystal bone, some amount of crestal bone loss occur when the abutment is a added.

28. If no para functional habits, cortical bone & soft tissue are thick � the platform of the crest module of the implant is placed level with the crestal bone. If a threaded implant is used tapping procedure may be needed. This creates threads in the alveolar bone to achieve a higher percentage of bone implant contact during healing phase. Bone tap should be used at very slow speed (30 rpm) under copious irrigation.

29. Implant placement: The implant sites are flushed with saline to remove any debris oral suctioned to reduce hydrostatic pressure during implant insertion. The direction indication pins may still be needed in the implant in the correct position The implant body is pre-sterilized and handling may alter its surface chemistry therefore; it should be placed directly into the implant site by means of a pre attached insertion mount. The marginal cortical bone should seal the periphery of the implant without any voids or cracks. Any such defects must be filled with cortical bone harvested during osteoplasty. The internal aspect of the implant bodies is thoroughly irrigated to remove any blood or debris before placement of cover screw. An antibiotic paste may be placed on the threads of the cover screws to help seal the cover screw to implant body connection and decrease the risk of the bacterial growth in the implant body during healing. The cover screw should not be over tighted.

30. Closure of Flap The crestal bone is evaluated for any sharp edges, which may be removed. The surgical site thoroughly irrigated with saline to remove any debris or bone fragments The lingual retraction suture are cut & removed. The flap edges are reapproximated without any tension. A combination of the inverted mattress suture and interrupted suture is recommended. The inverted mattress sutures keep the bleeding edges of the flap together while the interrupted sutures seal the edges.

31. Post operative care: Premedication with antibiotic starting immediately before the surgery and continuing for at least 1 week. Adequate analgesic to control pain E/o ice application � reduces swelling Chlorhexidine gluconate mouth rinse twice daily . Pt should have liquid diet or semisolid diet for the first few days & than gradually returns to a normal diet. No tobacco or alcohol use An OPG may be taken at the end of stage � I surgery to evaluate the proper placement and relationship of the implant to opposing landmarks or surrounding structures. Any correction should be carried out at this visit.

32. Second stage surgical tech: Objectives: To expose the submerged implant without damaging the surrounding bone To contact the thickness of the soft tissue surrounding the implant. To preserve or create attached keratinized tissue around the implant. To facilitate oral hygiene To ensure proper abutment seating Procedures: In case of adequate zone of keratinized tissue, as the gingiva covering the head of the implant may be punched out. A full thickness flap tech may be used that places a band of keratinized tissue on both sides of the implants. In case of deficient keratinized tissue � A partial thickness flap gingivectomy tech can be used to fulfill the objective.

33. After giving local anesthesia A sharp blade is used to eliminate all tissue coronal to cover screw. The cover screw is then removed the head of the implant is thoroughly cleaned of any soft or hard tissue overgrowth and the healing abutment or standard abutments are placed on the fixture. Once the implant is exposed it is important to remind the pt for need for good oral hygiene around implant. A chlorhexidine rinse is highly recommended for at least the initial 2 weeks while tissues are healing. At any time there should not direct pressure to area from dentures � Fabrication of suprastructure can begin in about 2 weeks.

34. ONE STAGE ENDOOSSEOUS IMPLANT SURGERY: In one stage surgery the implant or the healing abutment is kept protruding 2 to 3 mm form the bone crest & flaps are adapted around the implant. Surgical tech: Flap design & Incision: A crestal incision always used in one stage surgery bisecting the existing keratinized tissue. Vertical creasing incision may be needed at one or both ends. Preparation of Implant site: This is identical to that described in stage I of two stage implant surgery Placement of Implant: The implant is placed as described earlier in such a way that the head of the implant precedes about 2-3 mm forms the bone crest. Post operative care: Same protocol is followed.

35. Prosthetic Procedures: The third treatment stage consists of the prosthetic procedures which starts about 2 weeks after the abutment exposure. The fabrication of the implant-anchored prosthesis resembles that of a conventional fixed partial dentures. The fixed prosthesis is electively removable as it is attached to abutments by locking screw placed in vertical canals through the occlusal or lingual surfaces of the prosthetic teeth. Some times in single tooth it may be cemented to abutment. The prosthesis must have an optimal occlusion to ensure proper & even stress distribution to the Osseo integrated abutment fixtures, which cannot move to compensate for possible occlusal or other technical discrepancies. Care should be taken to design prosthesis with interproximal spaces ridge enough for easy access for oral hygiene measures.

36. Implant Maintenance In natural dentition the junctional epithelium provides a seal at the base of the sulcus against the penetration of chemical & bacterial substances. If the seal is disrupted the epithellium migrate rapidly in apical direction, forming a pocket. B�coz there is no cementous or fibers insertion on the surface of endosseous implant the permucosal seal is imp. The maintenance of implants therefore requires continues effort on the part of the pt dental hygienist & dental surgeon. Plaque control should be started immediately after implant exposed to the intra-oral environment and monitored overtime.

37. Implant superstructures are often bulky and over contoured which makes traditional home care procedure more difficult Patient recalls should be at 3 � months intervals for first year and then on a semiannual basis. However some pt may requires more frequent follow up care. Recall visits should include Plaque assessment Mucosal inflammation Peri implant probing Mobility Suppuration Occlusal harmony Radiographic assessment

38. IMPLANT FAILURE / PERI IMPLANT COMPLICATION Osseo integrated dental implants; unlike implants & hardware used elsewhere in the body have different environmental and functional stresses because of trans-mucosal nature of their tissue position. The peri implant tissue arrangement is unique to the dental implants. Despite the long term predictibility of Osseo integrated implants, biological, biomechanical & esthetic complication can occur in a small percentage of cases. 1.Early implant failure may be related to- Poor surgical placement Premature loading Failure to achieve osseointegratation The long-term failures in Osseo integrated functional implant may be due to bacterial etiology-pre-implantation or due to biomechanical overload. Esthetic complication occurs in pt with high esthetic expectation & less optimal placement.

39. Technical implant failure: In clinical reality, weakness in prosthetic design & dimensions and other factors may result in implant practices. Balshi listed three categories of occurs that may explain implants fractures-Design & material. Non-passive fit of the prosthetic framework. Physiological & biomechanical over load. Fractures may occur in few cases out of thousand. The occurence of implant fracture can be kept to a minimum through the use of quality controlled implant design and the consideration of physical principal and biomechanical characteristics of various material and prosthetic design.

40. Abutment loosing and fracture: Screw loosing has been regarded to occur quite frequently in screw- retained fixed partial dentures. Report have shown anywhere from 6 % to 49 % screw loosing at the first annual checkup. Newer abutment design and higher torque level used to insert abutment screw have helped reduced the rate of loosing. Esthetic complication: Implant placement in the esthetic zone requires precise three dimensional tissue reconstruction and ideal implant placement. In case of anterior region implants, the placement of the implant has to be precise and in keeping with restorative plan. That is, it should enable the placement of the crown that gives a natural look of emergence from the alveolar ridge at a proper position & angulations. In case, the alveolar ridge width is not ideal and do not allow implant placement then regenerative procedure should be considered or else a prosthetic profile will be developed with unaesthetic result. Soft tissue maximum around the implant is very important to keep a natural look around the artificial tooth and prevent the collar of the implant from becoming visible. Unaesthetic results may be unacceptable to the pt who has a complication. In such cases the implant may need to be removed and retreatment planned if possible. Esthetic complication may be minimized by appropriate treatment execution.

41. Biological and Biomechanical Feature: Pathologic changes in the peri-implant tissue can be placed in the general categories of �Peri- implant � diseases. Peri-implant mucositis: Inflammatory changes which are confined to the soft tissue surrounding an implant can be defined as peri-implant mucositis. Peri- implantitis- progressive peri- implants bone loss in conjunction with a soft tissue inflammatory lesson. The two major etiological factors associated with resorbtion of crestal peri-implant bone tissue are bacterial infection and biomechanical factors associated with loaded implant site. Bacterial infection: If plaque accommodates on the implant surface, the sub-epithelial connective tissue becomes infiltrated by large number of inflammatory cells and the epithelium appears adhered and loosely adhered. When the plaque front continues to migrate apically, the clinical and radiographic sign of tissue detraction are seen around both implants and teeth; however, the size of the soft tissue inflammatory lesion & the bone loss is more around implants.

42. One reason for the increased inflammation around an implant might be the low-vascularity soft tissue band and the different in collagen / flowchart ratio of gingival tissue, which affect the defense mechanism around the implant as compared with there seen in tissue around the teeth periodontal ligament. Sub gingival bacterial flora associated with clinically inflamed implant site is different to that seen around � healthy � implants. Mombelli et al showed in a prospective study that the bacterial flora at failed implant sites consisted of gram-negative rods, including Bacteroides & Fuso-bacterium species. Failing implants, which were clinically characterized by increased mobility and peri-implant radiolucency and probing depth grater than 6 mm were associated with Actinobacillus actinomycetes, prevotella intermedia and Porphyromonas gingivalis in more than one third of the site examined by DNA analysis. (Becker et al). Implants in partially edentulous cases appears to be at greater risk for peri-implantitis than implants in completely or fully edentulous cases. This might be explained by the decrease in periodontal pathogens in implant sulci of the totally edentulous.

43. Biomechanical factor: Peri implant tissue do not accommodate increased biomechanical stresses because � Implants move minimally in bone as compared to natural teeth. With over load, micro fracturing of the bone occurs and this is irreversible even with control of the over load. A reduced area of support exists in the root form implant compared with that of natural teeth. The implant is placed in poor quality bone. The implants position, as the total amount of implants placed does not favor ideal load transmission over the implant surface. Pt has pattern of heavy occlusal function associated with Para function. The prosthetic supra structure does not fit the implant precisely. The loss of bone allows soft tissue invasion in to the space between the bone and implant. If stresses continue to be excessive or if bacterial is present, bone loss continue to be excessive.

44. A number of clinical parameters used to assess peri implant conditions- Evaluation of oral hygiene. Peri implant marginal tissue Bone implant interface. Criteria for implant success (Albertson, zard, Worthington, Erickson, 1956) Individual unattached implant that is immobile when tested clinically. Radiograph that does not demonstrate evidence of peri implant radiolucency. Bone loss that is less than 0. 2 mm annually often the implant�s first year of service. Individual implant performance that is characterized by an absence of persistent & low irreversible sign & symptom of pain, injection, neuropathies, paraesthesia or violation of the mandibular canal. The implant design does not preclude placement of a crown or prosthetic with an appearance that is satisfactory to the patient and the dentist. The long-term success of dental implants depends on the continued health of peri-implant hard and soft tissue and an appropriate force distribution to the implants. Soft � tissue health should be established by obtaining a high level of pt compliance for plaque removal and having a prosthetic design that follows perioprosthetic guidelines