In implant dentistry, case selection is paramount in obtaining proper wound healing and metabolic stability after implant and bone grafting procedures. Some medical conditions may predispose the patient to compromised responses to surgical procedures, which may lead to infection, impaired healing or possible failure. Therefore, these disease states must be carefully evaluated by the clinician preoperatively.

• Present and past medical history
• Present and past dental history
• Present and past medication use
• History of allergies
• Social history and use of recreational drugs
• Type of intended treatment
• Length of treatment
• Invasiveness of treatment
• Psychological status
• Degree of treatment urgency
• Use and type of sedation

There are many factors associated with assessing the patient’s health status and risk, including the patient’s current and past medical and dental history, current and past use of medications, history of allergies, and social history (Table 1). When evaluating systemic diseases, a wide range of direct effects to dental implant treatment may be present depending on the severity of the disease. For example, a diabetic patient with a hemoglobin A1c (HbA1c) of less than 6% has no limitations to treatment and is considered to be in the category of “no contraindication.” If this patient had an HbA1c of 6%–8%, this would be classified as a “relative contraindication.” If the same patient had an HbA1c of greater than 8%, then the patient is considered to be in the category of an “absolute contraindication.” Therefore, in a general sense, one can see how the severity or degree of control of a disease has a direct effect on treatment contraindications (Fig. 1).

ASA1: Normal, healthy patient

ASA2: Patient with mild systemic disease with no functional limitations (e.g., controlled hypertension, controlled diabetes, chronic obstructive pulmonary disease with mild symptoms)

ASA3: Patient with severe systemic disease with definite functional limitations (e.g., uncontrolled hypertension, uncontrolled diabetes, chronic obstructive pulmonary disease with exercise intolerance)

ASA4: Patient with systemic disease that is a constant threat to life

ASA5: Moribund patient who is not expected to live less than 24 hours

In 1941, the American Society of Anesthesiologists (ASA) adopted a physical status classification system based on the severity of the patient’s underlying conditions (Table 2).⁷ This system is universally used in medicine today. Although the classification was originally designed to estimate the medical risk for a patient receiving general anesthesia for a surgical procedure, it is now utilized as a general evaluation for medical risk. Weyant et al., in a retrospective analysis of the Veterans Affairs registry data, found that the medical status of patients (i.e., medical history, ASA category and medication history) correlated with dental implant failure.⁸ Ideally, dental implant patients should be classified as ASA1 or ASA2 for dental implant treatment. In some cases, ASA3 patients may be treated, but only after medical consultation and clearance.

The two basic categories of information addressed during the review of the patient’s medical history are the following: 1) medical history; and 2) systemic health. In most cases, dental offices use a medical evaluation form to obtain the majority of this information. A review of the body systems via a patient interview should be completed, and any positive answers should be further investigated.

In addition, a history of medication usage — including prescribed medications, over-the-counter medications, herbs and supplements — and systemic and drug allergies should be detailed. The specific medications being used to treat any medical condition should be noted along with a history and dosage information collected. It is of utmost importance that all information on the medical forms be reviewed with the patient to ensure all questions are answered accurately and truthfully.

Systemic diseases play a vital role in treatment planning and implant therapy for patients. The effects of systemic disease on wound healing, bone metabolism and implant success are well documented in the literature. The implant clinician should utilize the specific systemic disease information obtained in the medical history in the planning and management of all phases of dental implant treatment. It is the responsibility of the implant clinician to understand the interrelationship of systemic diseases and the various treatment phases of implant dentistry.

As stated prior, the severity and degree of the systemic disease may be far more significant than the nature of the disorder itself. Therefore, a comprehensive evaluation should be completed in the decision process prior to implant therapy. For many of these patients, the increased quality of life and functional benefits from dental implants may outweigh the risks involved in performing the procedure. To assist in making these decisions on a patient’s treatment, the various types of contraindications must be understood.

In traditional medicine today, a contraindication is defined as a condition or situation that potentially makes the procedure in question inadvisable. There are two types of contraindications:

• Absolute contraindication is a condition that may result in major and significant medical problems with a high incidence of implant or bone graft failure. The risk of performing the procedure clearly outweighs any possible benefit. Undertaking procedures when these conditions are present is inadvisable.
• Relative contraindication is a condition that necessitates caution and is acceptable as long as the benefits outweigh the risks. In most cases, precautions need to be taken and the intended procedure may require some degree of modification to ensure safety and success.

To further clarify the contraindications in the field of implant dentistry, they may be classified into three categories (Table 3):

• Surgical contraindication: A condition that places the patient at medical risk during the surgical procedure (e.g., advanced cardiovascular disease) that potentially could result in a medical emergency. However, the condition does not directly impact morbidity or success of the implant procedure.
• Implant contraindication: A condition that places the endosseous implant healing at risk (e.g., IV bisphosphonate use), which may result in a decreased success rate and increased morbidity. However, the condition does not impact the intraoperative medical condition of the patient or place the patient at a medical risk.
• Surgical/implant contraindication: The combination of a surgical procedure risk with a risk for the success of implant healing or longevity. For example, with uncontrolled diabetes: 1) a patient may be predisposed to medical complications because of associated cardiovascular disease; and 2) implant healing may be impaired because of the uncontrolled diabetes.

Surgical Contraindications

• Uncontrolled hypertension
• Advanced chronic obstructive pulmonary disease (COPD)
• Unstable angina
• Class 4 congestive heart failure
• Recent myocardial infarction
• Bleeding disorders

Implant Contraindications

• IV bisphosphonate use
• Uncontrolled diabetes
• Immunosuppressive medications
• Heavy tobacco habit or alcohol use
• Uncontrolled hypothyroidism
• Past radiation therapy to the surgical site
• Titanium allergy

Obtaining a medical consultation/clearance is a necessity with patients who present with complicated systemic conditions, medications and predisposing factors that may lead to treatment complications. Collaboration and coordination with the patient’s health care provider is paramount in meeting the goal of safety and improving the patient’s health.

Clinicians must have a clear understanding of the difference between a “medical consultation” and a “medical clearance.” A medical consultation is defined as a procedure that is requested by one healthcare provider to another, which involves reviewing the patient’s medical history, examination of the patient, and recommendations for care and treatment. In contrast, a medical clearance is an official authorization, usually in writing, to allow a procedure to proceed. This is often troublesome to many physicians, as a potential liability situation may result. In addition, dentists may believe that because they have clearance, they are free of liability because they obtained permission and authorization to proceed with the procedure. This is often misleading and may place the dentist in a compromised medicolegal situation. In general, the dentist is ultimately responsible for any decisions and treatment he or she provides to the patient, as no patient is completely free of risk when undergoing a procedure.

Therefore, to protect the dentist and patient, a hybrid medical consultation/clearance form was designed by the author and Francis J. DeLuca, DMD, J.D. The intent of this form is to fully educate the physician on the intended procedure, protect the dentist medicolegally, and provide the dentist with sufficient information to make an informed decision on whether to proceed with treatment (Figs. 2a, 2b).

A cover letter should always be provided to the physician with the following information:

1. Introduction of the dental provider and the patient in question
2. Intended procedure (e.g., placement of two implants in the maxillary posterior region)
3. Date of the intended procedure
4. The type of anesthesia (local) and sedation (oral, conscious or general)
5. Duration of procedure (e.g., two hours)
6. Anticipated blood loss (e.g., minimal,moderate, severe)
7. Contact information

The physician will provide the following information:

1. Most recent physical examination: To determine whether the patient is keeping up with his or her medical health.
2. Significant medical condition, treatment, disease or injury: This will allow the physician to make the dentist aware of a particular medical condition that may have a direct impact on the treatment. In addition, the physician may relate a medical condition that the patient failed to divulge.
3. Medication modification: The physician will recommend any modifications to current medications (i.e., medications the patient is currently taking that were prescribed by another healthcare provider) or proposed medications (i.e., medications the dentist plans on prescribing as part of the dental implant treatment). A dentist should never modify any medication that was prescribed by another healthcare provider without written authorization by the physician.
4. Is the patient an acceptable candidate? The physician will clear the patient for dental implant treatment in writing, which becomes part of the patient’s permanent chart.
5. Contacting the physician: The physician will document whether he or she prefers to discuss the treatment of the patient with the dentist.

Clinicians should be proactive in obtaining medical clearance for patients who have systemic diseases or are taking medications that may directly affect the implant process. Placing a dental implant is an elective procedure that requires meticulous evaluation of the patient’s past and present medical history. Dentists must understand that not every patient who presents for implant treatment may be a candidate. Many patients have underlying systemic issues and comorbidities that may result in physiologic alterations to the body’s ability to combat procedural stress and allow for proper implant healing. A prudent clinician should possess the ability to disseminate information obtained on the medical history and ensure that the benefits of treatment outweigh the potential risks.