International Journal of Dental and Health Sciences Review Article Volume 04,Issue 02

PROSTHETIC FACTORS CONTRIBUTING TO FAILURE OF OSSEOINTEGRATED ORAL IMPLANT Nazish Baig1, Babita Yeshwante2, Sneha Maknikar3, Sonali Patil4, Supriya Deshpande5, Swati Bhandari6 1.Professor And Guide, Department Of Prosthodontics, CSMSS Dental College And Hospital, Aurangabad 2.HOD And Professor Department Of Prosthodontics CSMSS Dental College And Hospital, Aurangabad. 3.PG Student, Department Of Prosthodontics,CSMSS Dental College And Hospital,Aurangabad 4.PG Student , Department Of Prosthodontics,CSMSS Dental College And Hospital, Aurangabad 5.PG Student, Department Of Prosthodontics, CSMSS Dental College And Hospital, Aurangabad 6.PG Student , Department Of Prosthodontics,CSMSS Dental College And Hospital,Aurangabad

ABSTRACT: The ideal goal of modern is to restore the patient to normal contour, function, comfort, esthetics, speech and health.A major challenge for prosthodontists is the management of edentulous state and the constant desire of patient for fixed prosthesis. Though the science of restoration of missing teeth is as old as 300 BC with the Egyptians employing a variety of methods to secure the prosthetic teeth, the successful replacement of lost natural teeth by is a major advance in dentistry. What makes implant dentistry unique is the ability to achieve the ideal goal regardless of the atrophy, disease or injury of the stomatognathic system. However, the more teeth a patient is missing, the more challenging this task becomes. As a result of continued research, diagnostic tools, treatment planning, implant designs; materials, and techniques, predictable success is now a reality for the rehabilitation of many challenging clinical situations. Key Words: Implant , osseointigration

INTRODUCTION

Dental implants are an ideal option A successful implant is defined for people in good general oral health as an osseointegrated dental implant who have lost a tooth or teeth for the that is successfully restored and rehabilitation of many challenging contributing to the functional success clinical situations.[1] Dental implants are of a dental restorative treatment or biocompatible metal anchors surgically one that could be used for such positioned in the jaw bone to support an purposes. An implant failure is defined artificial where natural teeth are as a dental implant that is not missing. fulfilling this criterion. Early failure refers to an implant that fails to In 1969, Branemark et al osseointegrate before second-stage published landmark research, and surgery or uncovering of the documented the successful implant.Late failure refers to loss of of endosseous osseointegration or mechanical failure titanium implants. Since then, these of an implant after second-stage methods for surgical placement of surgery. Most research on the success dental implants have had a profound of dental implants concentrates on the influence on the practice of dentistry. first few years after placement. Research to date suggests that when

*Corresponding Author Address: Dr. Sneha Maknikar E-mail: [email protected] Baig N.et al, Int J Dent Health Sci 2017; 4(2):338-346 implants do fail, they tend to do so infectious component that is encouraged soon after placement, and the by microfractures in the bone and the likelihood of failure decreases from appearance of peri-implant pockets, with the time of implantation through 5 a clear infectious component. [5] We years post surgery. should neither fear nor embrace failure.

Implant treatment has a high success CLASSIFICATION OF IMPLANTS rate that has been rated as high as 95 to 99%,[2] despite high success rate with Dental implants may be classified under [6] endosseous titanium implants, failures four categories: unavoidably occur. At early stage, lack of A - Depending on the placement primary stability, surgical trauma, peri within the tissues operative contamination and occlusal B - Depending on the materials overload seem to be the most important used causes of implant failure.[3] The C - Depending on their reaction microbiological component plays an with bone important role in encouraging and D - Depending on the treatment facilitating implant infection during options implant placement, and also later when a - depending on the placement within the implant is in function in the mouth, the tissues - which is a septic medium. [4] 1. Endosseous Many causes have been studied on the 2. Subperiosteal subject of implant failures. Implant 3. Transosteal failure can occur at any time during b - depending on the materials used – treatment and subsequently when the implant is in function. Implant placement 1.metallic implants – Titanium, Titanium is contraindicated in many cases because alloy, Cobalt Chromium. the failure rate increases sharply, sometimes jeopardising oral health and 2.non- metallic implants – Ceramics, even the patient’s general state of Carbon etc. health. If there is no contraindication for c - depending on their reaction with undergoing the treatment, studies of bone – implant failure reveal two main causes of failure: infection and occlusal overload, 1.bioactive implants – Hydroxyapatite The first is associated with the phase prior to placing the implant in situ, in 2.bio-inert implants – metals direct relation with surgery, and the second is associated with implant d - depending on the treatment options function following prosthodontic Misch in 1989 reported five prosthetic rehabilitation. The latter also involves an options of implants, of the five the first 339

Baig N.et al, Int J Dent Health Sci 2017; 4(2):338-346 three are fixed prosthesis that may be On 5th October,2007, a Pisa, Italy partial or complete replacements, which Consensus Conference modified the in turn may be cemented or screw James–Misch Health Scale and approved retained. The fixed prosthesis are 4 clinical category that contain classified based on the amount of hard conditions of implant success, survival, and soft tissue structures that are to be and failure. replaced. The remaining two are removable prosthesis that are classified Survival conditions for implants may [7] based on the support derived. have 2 different categories:

FP- 1:Fixed prosthesis a)satisfactory survival: Implant with less than ideal conditions, yet does not Replaces only the crown; looks like a require clinical management natural tooth. b)compromised survival : Implants with FP- 2: Fixed prosthesis less than ideal conditions, which require clinical treatment to reduce the risk of Replaces the crown and a portion of implant failure. the root; crown contour appears normal in the occlusal half but is elongated or Health scale given by International hypercontoured in the gingival half. Congress of Oral Implantologists pisa based on clinical evaluation is as- FP- 3: Fixed prosthesis i. success (optimum health) - Replaces missing crowns and gingival color and portion of the a) No pain or tenderness upon function edentulous site;prosthesis most often uses denture teeth and acrylic gingival, b) No mobility but may be made of porcelain, or metal. c) 2 mm radiographic bone loss from RP-4: Removable prosthesis initial surgery

Overdenture supported completely d) No exudates history by implant. ii. satisfactory survival – RP-5: Removable prosthesis a) No pain on function Overdenture supported by both b) N0 mobility soft tissue and implant. c) 2–4 mm radiographic bone loss SUCCESS CRITERIA FOR DENTAL IMPLANTS d) No exudates history

iii. compromised survival – 340

Baig N.et al, Int J Dent Health Sci 2017; 4(2):338-346 a) May have sensitivity on function and symptoms of pain, infections, necropathies, paraesthesia, or b) No mobility violation of the mandibular canal.

c) Radiographic bone loss 4 mm (less In content of criteria mentioned, a than 1/2 of implant body) success rate of 85% at the end of a 5- year observation period and 80% at the d) Probing depth 7 mm end of 10-year observation as a e) May have exudates history minimum criterion for success.[8]

iv. failure (clinical or absolute failure) Further, in 1998 Esposito et any of following: al,[8][9] have listed out the following various criteria for success which were a) Pain on function agreed upon at the 1st European Workshop on . b) Mobility  Absence of mobility c) Radiographic bone loss 1/2 length of  An average radiographic marginal implant bone loss of less than 1.5 mm d) Uncontrolled exudate during the first year of function  Less than 0.2 mm annually e) No longer in mouth thereafter  Absence of pain/parasthesia REVISED CRITERIA FOR IMPLANT CLASSIFICATION OF IMPLANT FAILURE SUCCESS I. Esposito et al [8][9] classified implants ALBERKTSON, ZARB, WASHINGTON, AND according to the Osseointegration ERICKSON- Concept: I. Individual unattached implant that is - Biological immobile when tested clinically. - Mechanical II. Radiograph that does not - Iatrogenic demonstrate evidence of peri- - Inadequate patient education implant radiolucency. biological –A biological failure can be defined as the inadequacy of the host III. Bone loss that is less than 0.2 mm tissue to establish or to maintain annually after the implant's first osseointegration, It is of two types: year of service.  Early or primary (before loading): IV. Individual implant performance that failure to establish osseointegration. is characterized by an absence of persistent and/or irreversible signs

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Baig N.et al, Int J Dent Health Sci 2017; 4(2):338-346  Late and secondary (after loading): factors. The length of the implants, the failure to maintain the achieved quality of the bone, the number of osseointegration. implants, the opposing and the occlusal habits of the patient are all mechanical – important but perhaps the most important is the anterior and the  Fracture of implants, connecting posterior spread of the implants. screws, frameworks, coating etc. When a patient has occlusion on the cantilevered portion of the iatrogenic –can be defined as one edentulous fixed bridge although the characterized by a stable and forces are vertical in nature, a fulcrum osseointegrated implant, but due to line is established through the distal malpositioning, most implants. This is identical to the  Nerve damages, wrong alignment of situation in which a patient has occlusion implants, etc. on the distal extension bases of a distal extension removable partial denture. inadequate patient adaptation – With an implant supported fixed bridge, the cantilever suction is compressed Phonetical, esthetical, psychological towards the tissue, whereas the bridge problems, etc. anterior to the distal most implant has PROSTHETIC FACTORS IN IMPLANT tension occlusally. Bending results FAILURE through the fulcrum line that passes through the distal most implant.[10] Once the initial healing period has occurred, osseointegration then depends b - geometric load factors – on proper prosthetic design, regular Increased bending exerted on hygiene and maintenance of the implant implants has been identified and the and the prosthesis.[1] term bending overload has been a - forces on implants – proposed as a major risk factor for implant and implant component failure. Implants and implant components tolerate vertical forces well but not The number and position of lateral bending forces. It is implants define the geometric support demonstrated that bending elevate capacity for the prosthesis. Geometric stress to implant and bone and should load factors that can compromise the be minimized whenever possible. In support and result in increased bending designing the cantilever length of an overload include – edentulous fixed bridge in the mandible, 1. Fewer than three implants. for instance one looks at a number of

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Baig N.et al, Int J Dent Health Sci 2017; 4(2):338-346 2. Implants connected to teeth choice. This simple example is that of a stool. If one stool has two legs, there is 3. Implants in a line no resistance to bending, the stool with three legs contains the tripod effect with 4. Cantilever extension its resistance to bending. This tripod 5. Occlusal plane beyond the effect is so advantageous in the implants implant support in buccal or restoration that sometimes three lingual cantilevering and implants are planned when only two teeth are to be placed. The bending 6. Extensive crown: implant ratio. moment on a three implant restoration can be reduced 20% to 60%. If there is Most complications occurred on the two an offset between the implants of 2 to 3 implant restorations in which bending mm.Thus in order to maximize the overload was present. The inline chance for success and minimize the arrangement led to loose screws, broken chances for complications and failure, screws, increased bone loss and implant the placement of three implants for the failure. Overloading of an implant may establishment of a tripod effect is a lead to marginal bone resorption. Once sound approach for replacing three or bone resorption exceeds three threads more and sometimes two or more teeth the weaker portion of the implant below in a partially edentulous patient. In area the abutment screw engagement is of poor quality of bone we often go exposed and an increase in overload of beyond the tripod whenever possible. In the implant occur. The type of bone loss other words when replacing four teeth in seen in this situation is described as “ the posterior maxilla four implants cupping ”. This cupping pattern is a actually is recommended if possible.[1] rounded radiographic appearance of bone loss rather than a more horizontal c - crown implant ratio - or vertical straight line bone loss.This unique bone loss develops during this Crown implant ratio varies for totally period on which the fracture occurs and edentulous patient from that of the is a reaction to percolation to partially edentulous. Lateral forces on a inflammatory infiltrate from repeated restoration with a large crown implant micro-opening of initial fatigue cracks. ratio are much better tolerated in a full When this type of bone loss is noted one arch restoration and are not tolerated should be suspicious that fracture has well or at all in a partial edentulous occurred or is occurring and any patient with the same ratio. When a potential reason for overload should be unilateral implant restoration is to be examined. To avoid this overloading it is fabricated in a partially edentulous recommended to place three implants patient who has undergone significant when a three unit restoration is planned. resorption in the area, rebuilding the Three implants are the treatment of missing tissues with augmentation

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Baig N.et al, Int J Dent Health Sci 2017; 4(2):338-346 procedures should be considered the keep the cuspal inclination as flat as treatment of choices before placing and possible.In order to centralize the centric restoring implants. contacts as directly over the implants as possible to minimize bending in a d - occlusal design - posterior mandibular implant restoration one can design a lingulized occlusion in Besides the placement of three implants which the maxillary lingual cusps contact for a tripod support system there are the mandibular central fossa with no other considerations for minimizing the mandibular buccal cusp contacts. potentially damaging bending forces. Narrow occlusal tables minimize bending It is also important to note that even by preventing the forces from being too when a nice tripod is established, far beyond the fulcrum line. For attempts still should be made to instances, the further facial and buccal minimize bending. The occlusal table cusps are placed on a mandibular should be designed in a relatively narrow implant restoration, the further they are manner. The centric contacts should be cantilevered from the fulcrum line and located as directly over the implants as more bending is introduced. Although it possible the cuspal indentions should be is important to place the centric contacts relatively flat and if the remaining directly over the implants, often natural teeth can provide the lateral eliminating tooth to tooth contacts on guidance then the implants restoration the mandibular buccal cusps. Tooth to should provide only centric contacts. tooth contacts are not necessary to One occlusal load factor that perhaps by apply forces. Thus, the narrower the itself should prevent the consideration occlusal table or the closer the buccal of implant treatment is . It is cusps are to the buccal seating surface of difficult, if not impossible, ever to the restoration, the smaller the bending control the occlusal forces of these moments are when those buccal cusp patients or to maintain a constant function. occlusal scheme that could be protective of the implant restoration.[1] Lateral forces on an implant restoration introduce bending moments, therefore it e- strategic extraction- is important to establish centric contact over the implants but not lateral When planning implants in a contacts. The remaining natural teeth certain area to replace missing teeth, should provide the lateral guidance if one always considers carefully the only two implants are present the condition of the adjacent remaining occlusal design should include narrow teeth. By strategically extracting the occlusal tables, have centric contacts compromised adjacent tooth, not only only, centralize the centric contact over does one eliminate the potential for the implants as much as possible and more dental treatment in the near

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Baig N.et al, Int J Dent Health Sci 2017; 4(2):338-346 future but one also improves the CONCLUSION: support design of the implant restoration by placing more implants and Implant Failures that do occur may be providing on the tripod effect on related to patient variables, design and occasion, the extraction of a tooth does manufacturing of implants not necessarily depends on the health of compositional structure of implants, the tooth but rather on the overall certain design feature, skills of the rehabilitation provided. restorative and surgical members of the team and so on. Starting knowledge of f - tooth implant connection- the surgical and prosthetic possibilities for each of the team providers is of Two problems of connecting great benefit in treatment and towards implants to teeth have been prevention. When an implant fails, a documented. First of a rigid structure tailor made treatment plan should be like implant is connected to a non-rigid provided to each patient according to structure (tooth) the more mobile of the all relevant variables. Patients should be two may act like a cantilever and result informed regarding all possible in the application of increased load to treatment modalities after implant the rigid structure. Second if a non-rigid failure and give their consent to the connector is used there is a tendency for most appropriate treatment option for the teeth to intrude with this intrusion them. The first 2 years after implant there is a much greater risk of bending placement appear to be the most overload because any potential support critical in determining whether any by the natural tooth is lost. Certainly implant will be successful. The use of there have been numerous connection osseointegrated implants as a design such as rigid attachments, non- foundation for the prosthetic rigid attachments and telescopic replacement of missing teeth has copings, but due to the differences in the become widespread in the last decade. support system it is still recommended to avoid the potential load factor risk if Owing to the remarkable success of at all possible. dental implants, there has been growing interest in identifying the factors The best solution is to design the associated with implant failure. The implant restoration to be fully implant majority of the past and current supported and to place an adequate literature implicates smoking as one of number of implants in the proper the prominent risk factors affecting the positions. Connecting an implant to a success rate of dental implants. natural tooth to help the implant is not Smoking also has a strong influence on practical because any implant that needs the complication rates of implants: it the help of natural tooth probably causes significantly more marginal bone [1] should be removed. loss after implant placement, it

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