Amalgam--resurrection and redemption. Part 2: The medical mythology of anti-amalgam.

Mercury-containing amalgam restorative material has come under attack for its alleged harmful effects on systemic health. A literature search revealed that amalgam restorations release small quantities of mercury but apparently not enough to cause systemic health problems. Mercury from dental amalgam restorations cannot be linked to kidney damage, Alzheimer's disease, multiple sclerosis, other central nervous system diseases, "amalgam disease," mental disorders, damage to the immune system, increases in antibiotic resistance, or harmful reproductive effects. Dentists occupationally exposed to mercury have not been shown to suffer harmful reproductive or other systemic health effects, provided proper mercury hygiene is used. There are legitimate health concerns about alternative restorative materials, including resin composite. According to the latest scientific information available, dental amalgam remains a safe and effective restorative material.

Pain on injection of prilocaine plain vs. lidocaine with epinephrine. A prospective double-blind study.

BACKGROUND: Prilocaine has been described as causing less pain on injection than lidocaine with epinephrine, possibly because of the higher pH of the prilocaine anesthetic solution. METHODS: Three hundred ten consecutively seen patients in a general practice received a total of 334 maxillary buccal infiltration or inferior alveolar block injections, administered under clinical conditions by one of two dentists. Immediately afterward, patients rated the pain from each injection on a six-point scale. Twenty of these patients (in 21 separate appointments) received, and were asked to rate the pain associated with, a second injection of a contralateral tooth. The authors analyzed the pain response by operator, location of injection, patient's age, patient's sex and anesthetic. RESULTS: The difference in perceived pain between lidocaine and prilocaine was not statistically significant. Regardless of the anesthetic used, the perceived pain was usually no more than mild. Of 334 injections, 292 (87 percent) were rated as causing either no pain or mild pain. CONCLUSIONS: Under clinical conditions, there is no statistically significant difference between injection pain associated with prilocaine plain vs. that associated with lidocaine with 1:100,000 epinephrine. CLINICAL IMPLICATIONS: Since there is no significant difference in associated pain on injection between prilocaine plain and lidocaine with 1:100,000 epinephrine, dentists may prefer lidocaine with epinephrine. Since there is less anesthetic in each cartridge of lidocaine, it may require the use of less anesthetic per patient, and the vasoconstrictor can prolong its duration.

Amalgam--Resurrection and redemption. Part 1: the clinical and legal mythology of anti-amalgam.

Dental amalgam has come under attack for its allegedly poor physical properties and clinical performance in addition to its poor appearance. It has been claimed that the American Dental Association has a hidden agenda to protect amalgam and that other countries have banned its use. A literature search revealed that the vast majority of amalgam restorations do not cause fractured cusps or have recurrent caries. Most amalgam restorations have been shown to last longer than resin composite restorations. In addition, the materials and techniques involved in amalgam restorations have vastly improved in recent years. Like resin composite restorations, amalgam restorations can often be repaired. The American Dental Association has no vested interest in protecting amalgam. The use of amalgam has not been banned in any country in the European Union. According to the latest scientific information available, dental amalgam is a remarkably durable and long-lasting restorative material. Although its appearance is unesthetic, its clinical performance and effectiveness are unsurpassed by those of resin composite.

Myths of dental surgery in patients receiving anticoagulant therapy.

BACKGROUND: Continuous anticoagulant therapy with warfarin is administered to prevent a variety of medical complications, including thromboembolisms and stroke. When patients receiving continuous anticoagulant therapy are scheduled for dental surgery, a decision must be made whether to continue or interrupt the anticoagulant therapy. METHODS: The author reviewed the literature, focusing on dental surgery in patients receiving continuous anticoagulant therapy and in patients whose anticoagulant therapy was withdrawn before they underwent dental procedures. RESULTS: Of more than 950 patients receiving continuous anticoagulant therapy (including many whose anticoagulation levels were well above currently recommended therapeutic levels) who underwent more than 2,400 surgical procedures, only 12 (< 1.3 percent) required more than local measures to control hemorrhage. Only three of these patients (< 0.31 percent) had anticoagulation levels within or below currently recommended therapeutic levels. Of 526 patients who experienced 575 interruptions of continuous anticoagulant therapy, five (0.95 percent) suffered serious embolic complications; four of these patients died. CONCLUSIONS: Serious embolic complications, including death, were three times more likely to occur in patients whose anticoagulant therapy was interrupted than were bleeding complications in patients whose anticoagulant therapy was continued (and whose anticoagulation levels were within or below therapeutic levels). Interrupting therapeutic levels of continuous anticoagulation for dental surgery is not based on scientific fact, but seems to be based on its own mythology. CLINICAL IMPLICATIONS: Dentists should recommend that therapeutic levels of anticoagulation be continued for patients undergoing dental surgery. Practitioners should consult with the patient's physician if necessary to determine his or her level of anticoagulation before performing dental surgery.

Demystifying medical complexities.

Although dentists often fear treating medically complex patients, in many cases this fear may be based not on scientific facts but rather on a "mythology" of the dangers of dentistry. Dentistry is a remarkably safe profession, even for most medically complex patients. The myths of endocarditis, artificial joint infections, local anesthetics and vasoconstrictors, dental surgery in anticoagulated patients and patients on antiplatelet drugs, and antibiotic interference with oral contraceptives are discussed. Although dental treatment is not usually a risk factor for endocarditis, practitioners should consult the 1997 American Heart Association statement for recommendations for endocarditis prevention. Most artificial joint patients should not receive antibiotic prophylaxis. Local anesthetics and vasoconstrictors can be used safely in most medically complex patients. Neither continuous anticoagulation nor antiplatelet medications should be withdrawn for dental surgery. Scientific studies have failed to document an interaction between antibiotics used in dentistry and oral contraceptives.

The focal infection theory: appraisal and reappraisal.

This paper discusses the past, present, and future of the focal infection theory of disease. A focal infection is a localized or general infection caused by the dissemination of microorganisms or toxic products from a focus of infection. The resurgence of the focal infection theory of disease has been greeted with great enthusiasm in some quarters; however, the present evidence for the relationship of oral microorganisms and systemic disease is very limited due not only to a dearth of prospective studies and a complete lack of interventional studies but also to very significant methodological difficulties associated with the clinical studies that have been performed.

Dental surgery in anticoagulated patients.

Continuous oral anticoagulant therapy has been used to decrease the risk of thromboembolism for more than half a century, prolonging the lives of thousands of patients. Many physicians recommend interrupting continuous anticoagulant therapy for dental surgery to prevent hemorrhage. In reviewing the available literature, there are no well-documented cases of serious bleeding problems from dental surgery in patients receiving therapeutic levels of continuous warfarin sodium therapy, but there were several documented cases of serious embolic complications in patients whose warfarin therapy was withdrawn for dental treatment. Many authorities state that dental extractions can be performed with minimal risk in patients who are at or above therapeutic levels of anticoagulation. There are sound legal reasons to continue therapeutic levels of warfarin for dental treatment. Although there is a theoretical risk of hemorrhage after dental surgery in patients who are at therapeutic levels of anticoagulation, the risk appears to be minimal, the bleeding usually can be easily treated with local measures, and this risk may be greatly outweighed by the risk of thromboembolism after withdrawal of anticoagulant therapy.

Altering anticoagulation therapy: a survey of physicians.

Patients who take antithrombotic medications, such as warfarin sodium or aspirin, are more likely than others to experience bleeding problems after some dental treatments. Withdrawing the medication before treatment, however, may place these patients at risk of medical complications. The authors surveyed physicians about the conditions under which such pharmacotherapies should be altered. They not only found a difference of opinion among the respondents, but also learned that many respondents misunderstood the nature of certain dental procedures and the likelihood that those procedures would cause significant postoperative bleeding.

Myths of single-visit endodontics.

There has been much controversy about the safety and efficacy of initiating and completing endodontic therapy in a single visit. The literature concerning single- and multiple-visit endodontics is reviewed, and advantages and disadvantages of single-visit endodontics are discussed. Single visit endodontic therapy is shown to be a safe, effect alternative to multi-visit treatment for most vital and nonvital teeth.

Clinical issues in the prevention of dental-induced endocarditis and prosthetic joint infection.

No issue in medicine or dentistry is the subject of more misunderstanding than the prevention of infective endocarditis and late prosthetic joint infections. To resolve some of the confusion, national medical groups have published guidelines for the prevention of these infections, including the use of antibiotic prophylaxis for certain dental procedures and certain at-risk patients. While these guidelines are helpful, there still are clinicians who either do not recommend antibiotics when indicated or recommend antibiotics without indication. An understanding of these issues helps to prevent not only the infections but also the adverse antibiotic effects and associated legal problems. The learning objective of this article is to educate clinicians on the prevention of dental-induced endocarditis and prosthetic joint infections.