Test procedure	Units	Reference range
Sodium	mmol/L	135-146
Potassium	mmol/L	3.5-5.3
Chloride	mmol/L	98-110
Carbon dioxide	mmol/L	21-33
Calcium	mg/dL	8.6-10.2
Alkaline phosphate	Units/L	33-130
AST	Units/L	10-35
ALT	Units/L	6-40
Bilirubin, total	mg/dL	0.2-1.2
Glucose	mg/dL	65-99
Urea nitrogen	mg/dL	7-25
Creatinine	mg/dL	0.60-1.18
BUN/creatinine ratio		6-22
Protein, total	g/dL	6.2-8.3
Albumin	g/dL	3.6-5.1
Globulin, calculated	g/dL	2.2-3.9
A/G ratio		1.0-2.1
Egfr non-African American	mL/min/	1.73 m² > or = 60
Egfr African American	mL/min/	1/73 m² > or = 60

Combining the information from the health questionnaire, the vital signs, and the laboratory test results will enable the doctor to categorize each patient into one of the five classifications of presurgical risk formulated by the American Society of Anesthesiology (Box 5-1).⁸ According to this scheme, a Class I category includes the patient who is physiologically normal, has no medical diseases, and lives a normal daily lifestyle. The Class II category includes the patient who has some type of medical disease, but the disorder is controlled with medications. The patient can thus engage in normal daily activity. An example of this category of patient is one with hypertension who has been placed on antihypertensive medication and, as a result, has normal blood pressure and no other impairments. The Class III category includes the patient who has multiple medical problems, such as advanced-stage hypertensive cardiovascular disease or insulin-dependent diabetes, with impaired normal activity. Patients in the Class IV and V categories have advanced states of disease. Class VI is a patient who is considered brain dead and is a potential organ donor. For example, a patient in the Class IV category has a serious medical condition requiring immediate attention, such as the person with acute gallbladder disease who needs immediate treatment. The patient in the Class V category is usually moribund and will not survive the next 24 hours. Most patients who seek implant reconstruction fall into the Class I or II categories and sometimes Class III. For obvious reasons, patients in Classes IV and V are not appropriate candidates for implant procedures. However, consideration of whether a patient falls into Class I, II, or III will enable the implant practitioner to more effectively decide what kinds of procedures should be undertaken, where the surgery should be performed, and what kind of anesthesia is appropriate. Furthermore, cases with patients categorized as Class III may require preparatory measures such as stabilizing or controlling a diabetic patient before implant surgery can be considered.

BOX 5-1 The American Society of Anesthesiologists’ classification of presurgical risk

Patients who manifest systemic disease that interferes with their normal daily living pattern (e.g., inhibits their employment, restricts their social activity, or otherwise does not allow them to function physically and mentally in a normal or almost normal manner) should not be considered as candidates for an elective procedure such as oral implant reconstruction (R,R). Classifying patients according to the following numerical ratings as established by the American Society of Anesthesiology is helpful in the selection process (R):

Class I: A patient who has no organic disease or in whom the disease is localized and causes no systemic disturbances.

Class II: A patient exhibiting slight to moderate systemic disturbance which may or may not be associated with the surgical complaint and which interferes only moderately with the patient’s normal activities and general physiologic equilibrium.

Class III: A patient exhibiting severe systemic disturbance which may or may not be associated with the surgical complaint and which seriously interferes with the patient’s normal activity.

Class IV: A patient exhibiting extreme systemic disturbance which may or may not be associated with the surgical complaint, which interferes seriously with the patient’s normal activities, and which has already become a threat to life.

Class V: The rare person who is moribund before operating, whose preoperative condition is such that the patient is expected to die within 24 hours even if not subjected to the additional strain of surgery.

Class VI: A patient who is considered brain dead and is a potential organ donor.

Dental Status

It is essential to obtain a comprehensive understanding of the patient’s dental, as well as medical, status. In addition to questioning patients about their dental history, a thorough examination should be conducted. An evaluation of the hard and soft tissues of the entire maxillofacial skeleton should be included and appropriate radiographic studies must be obtained.

Today’s modern dental offices can provide a host of radiographic information through digital and computer analog equipment that allows unprecedented detail and data applications never available before. Digital panoramic and office-based cone beam CT scanners (Figure 5-2) are now readily available. These devices can give studies that accurately define the full scope of the maxilla and mandible, as well as the accompanying vital structures (i.e., sinus, floor of the nose, position of the mandibular canal, mental foramen) (Figure 5-3). In addition, information about the thickness of cortical plates, bone densities, and soft tissue contours is easily obtained. Chapter 8, Contemporary Radiographic Evaluation of the Implant Candidate, and Chapter 18, An Introduction to Guided Surgery, expand on this technology. There still is a place for conventional film-based radiographs because much valuable information can be learned from them. These might include occlusal films, lateral cephalometric images, and periapical or panoramic images (Figure 5-4).¹⁰ However, with the advent of digital referenced planning software our ability to diagnose and plan procedures virtually takes radiographic diagnosis and treatment planning to a new level (Figures 5-5 and 5-6).