Implications of Amalgam and Ceramic Degradation in the Oral Environment
- PDF / 3,633,527 Bytes
- 9 Pages / 576 x 777.6 pts Page_size
- 39 Downloads / 237 Views
64
of these materials and subsequent physiological side effects.
Oral Galvanism: The Mercury Debate During the late 1970s and the early 1980s, numerous patients in Sweden that had received dental treatment with metallic materials complained that they suffered from "oral galvanism." Their perception was that differences in electromotive force between different metallic fillings generated currents and corrosive effects. The currents caused oral sensations, and the perceived ion release was considered harmful by many patients. Epidemiological studies revealed that persons suffering from oral symptoms allegedly caused by oral galvanism did not have higher electrochemical current in their mouths than persons without the symptoms ascribed to oral galvanism.1"3 However, a correlation was found between the quality of the restorations and oral symptoms of patients who claimed that they suffered from oral galvanism.4 After performing clinical examinations, epicutaneous patch tests with dental materials, hematological analyses, salivary tests, calculation of currents created during metallic contact between restorative materials, and measurements of electrical taste thresholds, further evaluations were conducted.5 The most common symptoms reported were a tingling sensation in the mouth (71%) and a variety of symptoms
(47%) at sites distant from the oral cavity. The results of another investigation6 revealed that about half of the patients who complained of oral galvanism needed treatment for mandibular dysfunction. Patients suffering from oral galvanism were found to have a psychogenic component behind the reported complaints.7 These findings have been confirmed in other studies. Since the late 1980s, the frequency of this phenomenon has declined. A possible explanation might be that this patient group changed their attitudes as scientific evidence was presented to challenge their beliefs. Today, many of these patients still believe that their problems relate to mercury released from their amalgam restorations. Consequently, the symptoms have changed with additional knowledge of the patient about their environment.12 The oral galvanism issues developed into a mercury controversy and, from the mid-1980s to the present, Sweden has had a lively mercury debate, which has spread to other countries as well. The reason that amalgam biocompatibility studies became so intense in Sweden was partly related to the oral galvanism debate, but also stemmed from other issues. For example, environmental concerns grew strongly during the 1970s and 1980s in Sweden, and the realization among the public that dental amalgam restorations contained about 50% mercury further fueled the debate. Accordingly, dental amalgam restorations consist of approximately 50 wt% Hg and 20 wt% Ag (min.), 15 wt% Cu (max.), and 16 wt% Sn (max.), although other elements such as Pd, In, and Zn are used to alter the properties and working characteristics. The general chemical reaction for a typical product that contains 8 wt% or more of Cu and which is formulated as s
Data Loading...
