Classification of Dental Implant Complications

FIG 1.1 By 2050, 20.7% of the population will be older than age 65. In addition to the increasing percentage of 65-year-olds, the population is also increasing. As a result, 34.9 million people were older than 65 in 2000, and 86.6 million people will reach this milestone by 2050. (From Misch CE: Contemporary implant dentistry, ed 3, Mosby, St. Louis, 2008.)

An Accepted Treatment by the Population

The replacement of edentulous sites with dental implants is one of the most rapidly progressing disciplines in all of medicine. Advancements in the modification of soft and hard tissues, implant design, and prosthetic fabrication are leading to long-term success rates well over 90%. In addition, a surge of patient education materials for both dentists and their patients has led to a large increase in the public awareness of implants as a viable treatment modality. These factors are leading to explosive growth in the dental implant market.

Straumann corporation performed a penetration study that discussed the growth of the dental implant market by 2020. As of 2011, 15% to 20% of the population of patients seeking the replacement of a missing tooth or teeth received implant therapy as a restorative modality. This number is projected to increase to around 25% to 30% in just 9 years.6 The implant market is slated to grow 6% to 8% in this short time frame. TechNavio’s analysts forecast the global dental implant market to grow at a compound annual growth rate (CAGR) of 8.72% over the period 2014 to 2019. The overall dental implant market, which grew from $3.2 billion to $4.2 billion in 5 years, is expected to rise to over 6.5 billion by 2018.7

More Dentists Placing Implants

Due to the aforementioned boom of demand for oral implantology in the patient population as well as the lucrative nature of the procedure from an economic standpoint, more dentists are placing implants. Straumann reported that approximately 18% to 20% of US dentists are placing dental implants, with an average of 55–60 implants being placed by each clinician in a year. This is compared to a 2004 study by the American Dental Association (ADA) that had this number at 11%.8,9 As recently as 10 years ago, oral implantology was not emphasized in the dental school curriculum, but it is now being taught as a core component of a student’s education. The number of general practitioners placing implants is growing and will continue to grow in the future. Additionally, technological advances are making it easier and more profitable for clinicians to treat advanced cases.

Manufacturers Course Training

In the 2007 ADA survey, general practitioners were asked where they received their training in dental implant placement. Approximately 66% of these dentists had received specialty training after completing dental school. The bulk of the remaining practitioners had received their training in a course sponsored by a manufacturer. Due to the lack of exposure in the past to oral implantology in dental school, dentists are seeking quick access into the discipline for a low cost. Dental implant manufacturers are attempting to fill this void by hosting continuums in oral implantology for the dental population that is seeking an introduction to this discipline. Though these short courses are better than the alternative of having dentists receive no training at all prior to placing implants, there are definitely inherent drawbacks.

First, there is a lack of foundational didactic training on dental implant treatment planning, which is a cornerstone of successful treatment outcomes. A firm understanding on prosthetic design, force distribution, and site development is paramount to achieving consistent successful dental implant treatment outcomes. Secondly, the manufacturers tend to oversimplify the treatment protocols in an effort to embolden clinicians to offer implant placement in their respective practices. This places the dentist in a position of not being fully aware of the potential complications they can encounter during treatment and how to handle them should they arise.

Implants Being Placed in Compromised Sites

Due to the lack of formal training in comprehensive oral implantology, dentists may lack a firm appreciation for site development as it pertains to the hard and soft tissues. Many edentulous sites and prosthetic designs require modifications to the proposed implant site. There is a tendency for dentists (early on their learning curve) to develop treatment plans that allow them to avoid procedures they lack knowledge or comfort in, so implants may be placed in suboptimal areas, which leads to various negative esthetic, prosthetic, and surgical complications. Because of bone loss after tooth extraction, many sites are not ideal for implant placement (surgically and prosthetically). If the dentist lacks knowledge in bone grafting and site development, this may lead to alternative treatment options such as severely angled implant placement, excessively short implant bodies, or the placement of too few implants for the force requirements of the patient’s proposed prosthetic design. All of these “shortcut” or “non-ideal” procedures may lead to an increase in complications, lower success rates, and subsequent legal ramifications.

Financial motivation may also affect decision making as it pertains to site development. A dentist may feel the pressure to “keep procedures in house,” which may lead to a deviation of proper treatment planning, especially if the clinician does not possess the skill or knowledge required to augment hard and soft tissue. In areas of the mouth that show a lack of bone height, width, density, or a lack of adequate soft tissue, a practitioner will be required to have greater education, experience, and skill to navigate a proper treatment plan from the surgical phases to final prosthetic completion. Cases with compromised tissue volumes typically require augmentation prior to implant placement, which requires a separate skill set. If a clinician does not possess these skills but proceeds with a modified treatment plan to work around the inherent difficulties that the patient’s anatomy presents, numerous complications and morbidities can occur in all phases of treatment. This will ultimately lead to embarrassment, increased procedural cost, and possible legal repercussions.

Medically Compromised Patients

With the continued advent of new technologies, medications, and treatment options, patients are leading longer lives with higher degrees of social activity. This phenomenon will continue to increase as the population grows along with the understanding of disease prevention and treatment. The impact of this for the modern dentist is the presence of a population of elderly patients who actively seek comprehensive dental care, in a search for a return to optimal form, function, and esthetics.

As was previously discussed, oral implantology is becoming a larger part of this patient population’s knowledge base, and they are actively seeking this therapy to help enjoy a better diet, more active social lifestyle, and younger appearance. However, this also places a higher demand on the dentist to understand the medical complexities that are inherent in treating these patients. Patients present with numerous comorbidities, take many medications that may affect implant healing, and also pose a significant challenge for the clinician during the surgical phases of treatment.10 Additionally, significant advances in medicine have led to the advent of new medications for many diseases. However, the interaction of these medications on the healing of dental implants can cause many complications and adverse effects (i.e., bisphosphonates).

A survey study was performed showing that with patients in the 57- to 85-year range, 81% took at least one prescription drug daily, with 29% taking at least five medications.11 A practitioner performing implant surgery must know the patient’s medical history, have a firm understanding of each medication, and be aware of how each of these medications affects not only the patient’s ability to cope with the stresses of surgery but also the healing and integration of bone grafts and dental implants. Medications that are prescribed pre- and postoperatively may interact with the patient’s existing drug regimen. These factors must all be taken into consideration before beginning a treatment protocol. A lack of awareness of the effects of medication on dental implant treatment may lead to numerous unforeseen complications.

When planning to begin treatment on an medically compromised patient, the clinician must also understand how various medical conditions may affect the final outcome. Cardiovascular and respiratory disease may complicate surgery. Uncontrolled diabetes has significant effects on surgical healing and implant integration. Anticoagulant therapies may pose a significant risk for bleeding episodes during treatment. Long-term steroid use can affect healing and infection risk. Each affirmative check on a medical questionnaire should be investigated and evaluated for a risk of possible complications to surgery.

Lack of Medical Clearance Prior to Surgery

A key to success in treatment for the medically compromised patient is an area that is sometimes overlooked by the dental professional, and that is a strong working relationship with the patient’s physician. While performing the medical evaluation on a patient presenting with a positive health history, the implant dentist should take the time and effort to consult with the treating physician to establish a pre- and postoperative plan, including drug protocols, ensuring that the patient experiences an outcome free from drug interactions and medical complications. Surgical clearances should also be obtained in an effort to minimize the risk that a patient experiences medical complications or life-threatening emergencies during implant surgery. A failure to obtain such clearances puts the implant dentist in a serious medicolegal risk, should complications occur. (See the Medical Consultation Form in Chapter 2.)

Immediate Implant Procedures

Throughout the history of the discipline of oral implantology, research studies have been performed to help practicing clinicians understand all aspects of implant dentistry, in an effort to provide patients with the best chances of experiencing a successful outcome. These studies have shaped our understanding of how the body responds to the different implant and graft materials, how the forces of mastication act on these materials, and how the microbial environment affects the long-term success of implant restorations. As this understanding increased, designs for implants were established, treatment protocols and healing times were authored, and drug regimens were established to maximize the chance that treatments were successful.

However, as the demand for implant services has increased, so has competition in that marketplace. Dental professionals compete for patients, and dental implant manufacturers compete for market share. This has led to the advent of more and more dental implant procedures that deviate from the established clinical guidelines set forth and confirmed by previous research. Though many of these procedures and treatment protocols can work and have been shown to be effective in the right hands, the skill requirements of these procedures may prove to be too high for some practitioners, especially those early on a learning curve. This leads to numerous surgical and prosthetic complications.

In an effort to reduce the time in which a patient had to wait for a final restorative outcome, a movement began to not only immediately place an implant at the time of extraction but also to load the implants at the same time. In the right circumstances (proper bone volume, density for rigid fixation, and lack of infection), this treatment has been shown to be clinically effective. However, with the confirmation that these procedures can indeed work, we have seen an exploitation of the treatment protocol to encourage this type of procedure as a matter of routine. The pressures on implant dentists to produce “teeth in a day” may predispose them to taking shortcuts and making surgical compromises that put the patient at great risk for implant/prosthetic failure. The implant dentist must understand that certain clinical criteria must be present for these procedures to work, and that factors such as medical status, the presence of infection, or inadequate bone volumes contraindicate such shortcuts.

Catering to a larger population of dentists who may not possess the skills to create adequate bone volumes by grafting, manufacturers have also pushed the boundaries in implant design in an effort to remove barriers to entry into the implant field. For example, to avoid the problem of having to build posterior maxillary bone volumes to ensure proper vertical axis loading of implants, clinicians have invented techniques involving angled placements of implants with severely angled abutment interfaces. Although these techniques have been shown to be successful, surgical experience and case selection are crucial factors for long-term success.

Overuse of “Mini” Implants

Recently, the use of “mini” dental implants to support removable and fixed prosthesis has dramatically increased in implant dentistry. Initially, the intended application of mini implants was for provisional restorations during the healing phase of conventional endosseous implants (> 3.3 mm diameter). In time, the use of mini implants was expanded to retain removable and fixed prostheses, which have become extremely controversial. Manufacturers have since modified the procedure to include minimally invasive techniques, which include inserting the implant into the bone via flapless surgery. These techniques have been marketed toward faster, easier, and less traumatic procedures. However, this marketing has led to more mini implants being placed in sites that would be more ideally suited (surgically and prosthetically) for conventional endosseous implants. This has led to nonideal implant positioning, neurosensory impairment, atypical implant prosthesis, poor emergence profiles, biomechanical issues, and implant fractures.

At this time, there are very few studies evaluating the success of mini implant under functional biting forces and long-term success. Finite element stress analyses of mini implants have been shown to exhibit high levels of risk because stress transmission to bone and fatigue fracture. Bulard and Vance evaluated over 1000 implants and reported a 13.6% failure rate.12 Shatkin reported more failures in the maxilla with a 17% failure under a complete denture.13 Other studies have shown fatigue fracture to be responsible for 5% and 20% of all implants lost during function.14 Therefore, mini-implants definitely have a place in implant dentistry treatment planning, however in most cases should not be substituted for conventional size implants.

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Jan 12, 2018 | Posted by in Implantology | Comments Off on Classification of Dental Implant Complications
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