In dentistry today, the replacement of missing teeth with dental implants is becoming the standard of care. Yet despite the high predictability of dental implants for prosthetic rehabilitation, a small but significant portion of the population continue to experience implant failure; the identification of such patients is paramount to the treatment planning process.1 Proposed contraindictations to implant therapy can be divided into local and systemic factors. In a paper published for the second International Team of Oral Implantology (ITI) Consensus Conference, Buser et al. (2000) proposed to subdivide the general systemic risk factors into two groups: 2,3
- Group 1 (very high risk): Patients with serious systemic disease, immunocompromised patients, drug abusers, and non-compliant patients
- Group 2 (significant risk): Patients who received radiotherapy, severe diabetes (especially type 1), bleeding disorders, and heavy smokers
With the increasing refinement of both surgeons skill and implant design, mounting interest is being focused on patient specific and disease-related factors that may compromise implant osseointegration and survival. Diseases that impair the normal healing cascade decrease surgical success.4 However, the mere presence of disease in itself does not necessarily preclude implant therapy or affect implant survival rates. Detailed lists of diseases for which oral implant therapy is not recommended have been published, yet it is questionable on what level of evidence these recommendations are based.6
With the worldwide prevalence of diabetes increasing drastically, much research has focused at addressing the question, “Do diabetic patient’s experience greater implant failure than systemically healthy patients?” However to fully understand the implications of diabetes, it is important to understand the systemic compromises incurred due to this disease.
Diabetes is a common metabolic disorder characterized by hyperglycemia due to impaired insulin secretion, insufficient insulin action, or both.7, 8 Diabetes is classified into two different diseases, type I (T1DM) and type 2 (T2DM). T1DM accounts for 5% to 10% of individuals with diabetes and is caused by an autoimmune reaction destroying the beta cells of the pancreas, leading to insufficient production of insulin. T2DM is associated with a relative (rather than an absolute) insulin deficiency and accounts for 90% to 95% of diagnosed diabetics. Chronic hyperglycemia has been associated with various systemic complications, including nephropathy, neuropathy, retinopathy, micro- and macro-vascular disturbances, and impaired wound healing. Within the oral environment, periodontitis, caries, and xerostomia (“dry mouth”) have been linked to diabetes. The increased susceptibility to periodontitis (and thus alveolar bone loss) is postulated to be due to a hyper inflammatory state and apoptosis, resulting in a deregulated host defense, impairments in wound healing, and micro vascular problems.2 Thus, for these reasons, when the advent of implant dentistry occurred in the 1970s diabetic patients were not considered suitable for implant therapy.5
However, over the past decades diabetes has been regarded not as an absolute contraindication to implant therapy but rather a relative contraindication related to the stability of the diabetic patient’s blood sugar level.7 To further assess this question, I conducted a systematic review examining the effects of diabetes and glycemic control on the survival of dental implants. After completing a thorough review of all available literature to date addressing this question, it seems that the answer to this question is simple:
THERE IS NO SOUND DATA SUGGESTING HIGHER RISK OF IMPLANT FAILURE IN WELL-CONTROLLED DIABETIC PATIENTS
Upon closer examination, it seems the level of evidence indicating absolute and/or relative contraindications for oral implant therapy due to diabetes mellitus and treatment is low. Although diabetes mellitus has been postulated as a possible risk factor for implant failure, studies comparing patients with and without the disease in controlled settings are sparse. In general, the available literature is restricted to individual cohort studies, systematic reviews with gross heterogeneity, and case reports.
The ability to anticipate treatment outcome is a critical part of risk management in an implant practice. Recognizing systemic diseases that place a patient at increased risk of complications and/or failure allows the surgeon to make informed decisions and refine the treatment plan to optimize the probable outcome.5 Although it has been argued that diabetic patients may be at greater risk for impaired wound healing and thus oral implant failure than a non-diabetic patient, the results of this review suggest otherwise.
Today, diabetic patients are being successfully treated with oral implant retained prostheses. It seems that diabetics that undergo implant therapy do not encounter a higher failure rate than the normal population if the patient’s plasma glucose level is normal or even slightly elevated.5 Currently, it appears that practitioner comfort trumps all when it comes to what level of glycemic control a given surgeon is willing to allow as “acceptable” prior to implant placement. As the level of evidence of current studies addressing this question are fair at best, future research should focus on developing more randomized controlled trials to further and more accurately elucidate out the relationship between diabetic status and level of control with implant complications and/or survival. Hopefully then there will be enough strong data that a meta-analysis can be completed to more accurately address this issue. Such results could then aid surgeons during the treatment planning process in medically compromised patients and allow for proper risk-to-benefit analysis prior to implant placement.
- Moy PK, Medina D, Shetty V, Aghaloo, TL. Dental implant failure rates and associated risk factors. Int J Oral Maxillofac Implants. 2005 Jul-Aug;20(4):569-77.
- Bornstein MM, Cionca N, Mombelli A. Systemic conditions and treatments as risks for implant therapy. Int J Oral Maxillofac Implants. 2009;24 Suppl:12-27. Review.
- Buser D, von Arx T, ten Bruggenkate CM, Weingart D. basic surgical principles with ITI implants. Clin Oral Implants Res 2000;11(suppl):59-68.
- Hwang D, Wang HL. Medical contraindications to implant therapy: Part II: Relative contraindications. Implant Dent. 2007 Mar;16(1):13-23.
- Tawil G, Yunnan R, Azar P, Sleilati G. Conventional and advanced implant treatment in the type II diabetic patient: a surgical protocol and long-term clinical results. Int J Oral Maxillofac Implants. 2008 Jul-Aug;23(4):744-52.
- Mombelli A, Cionca N. Systemic diseases affecting osseointegration therapy. Clin Oral Implants Res. 2006 Oct;17 Suppl 2:97-103. Review. Erratum in Clin Oral Implants Res. 2006 Dec;17(6):746.
- Farzad P, Andersson L, Nyberg J. Dental implant treatment in diabetic patients. Implant Dent. 2002; 11(3):262-7.