DCA06DT Dental Treatment of Pediatric and Adolescent Patients _ __________________________________
DENTAL AMALGAM Dental amalgam has been used as a restorative dental material since the late 19th century [12]. It has been popular due to its durability, ease of placement, and low cost compared to other dental restorative materials. However, there has been controversy about the safety of dental amalgam use because mercury is one of the composite elements, along with cop- per, tin, and silver. Patients and parents may have concerns related to the release of mercury during the placement of new amalgam restorations and the removal of deficient restorations, or the continuous release of small amounts of mercury from the material. Numerous studies and reports by the American Dental Association, the American Medical Association, the World Health Organization, the Fédération Dentaire Inter- national (FDI), and the U.S. Food and Drug Administration have affirmed the safety and efficacy of amalgam restorative material [14; 82]. Studies have shown that mercury off-gassed from dental amal- gam (approximately 2–28 mcg per facet surface per day, with 80% absorbed by the lungs) accumulates in body tissues, partic- ularly the kidneys and brain, with higher levels associated with a greater number of fillings; this represents the most prevalent source of mercury exposure for most individuals [65; 67; 68]. Evidence of debilitating systemic effects from these accumula- tions is lacking, but there is increasing awareness regarding the impact of cumulative mercury exposure, particularly on cogni- tive functioning. In 2008, both Norway and Sweden banned the use of amalgam as a dental restorative material [15]. In the United States, amalgam is still used, but some parents will not permit its use for their restorative needs or for those of their children. This debate is global in nature and will continue. Parents of minors who require restorative dentistry should always be presented with options for use of various restorative materials prior to initiation of the procedure. The preparation of the tooth and placement of an amalgam restoration will depend on whether the carious lesion occurs in the deciduous tooth of a child, the permanent tooth of a child, or the permanent tooth of an adult. Amalgam does not have the capacity to self-adhere to enamel or dentin, and the form of the cavity may not be enough to retain the amalgam restorations. In these cases, auxiliary means of retention (i.e., small slots or grooves placed at the junction of the enamel and dentin) may be necessary. While this is not a problem in the permanent teeth of adults, careful placement is necessary to avoid pulpal involvement in children and adolescents. A primary advantage of amalgam over composite resins is that it is not as technique-sensitive in its placement. If blood or saliva contaminates a tooth surface, the bond strength of a composite restoration will decrease, causing microleakage and ultimately failure. While a similar circumstance is not ideal for the placement of amalgam, the material is not dependent on a bonding process and contamination will not interfere with its setting.
Amalgam is durable under compressive strength, but its inclu- sion does not strengthen the tooth. It is a restorative material, not cosmetic, and its appearance will worsen over time as intra- oral oxidation reactions cause it to darken. Larger amalgam restorations can also impart a gray or black discoloration to the adjacent enamel. In children and adolescents, preparation of the outline form for the restoration of deciduous posterior teeth is dependent on several factors. The point at which two adjacent teeth touch (i.e., the contact area) between deciduous molars is broader and flatter than the comparable contact area between permanent teeth, and this is an important consideration when placing class II restorations using amalgam or composite resin. Clinicians who are used to placing class II restorations in permanent teeth should be cognizant of these anatomic and restorative differ- ences. A class II restoration that would provide an adequate interproximal contact in a permanent tooth will not span the contact area of adjacent deciduous molars, which can lead to food impaction and an increased risk of recurrent caries. COMPOSITE RESIN Composite resin material was first introduced as a choice for the restoration of class III (interproximal lesions in anterior teeth), class IV (carious lesions or traumatic fractures of ante- rior teeth that involve the interproximal surface and the incisal edges), and class V lesions of both deciduous and permanent teeth. Numerous composite resin materials have now been developed to restore class I and class II lesions in deciduous and permanent posterior teeth. Beyond the cosmetic benefit, the use of etchants and bonding agents allows a chemical and mechanical bond to develop and secure the composite resin to enamel and dentin. Thus, less tooth structure is removed compared to amalgam, which cannot bond to enamel or dentin and relies on the reduction of additional tooth structure and retentive grooves or slots for mechanical retention. The primary considerations in the use of composite mate- rial for the restoration of posterior deciduous teeth are the additional time required in their placement, the additional cost, and the ability to isolate the tooth. As noted, the place- ment of composite resin restorations requires that the tooth be isolated from saliva and blood with a rubber dam. While this device provides excellent isolation, some patients will find it uncomfortable, feeling that it is confining and a barrier to communication with dental staff during the procedure. Children can be especially fearful of the rubber dam and may be uncooperative during its placement, which can jeopardize the successful placement of the restoration. Children may also become restless and uncooperative during the longer time required for the placement of composite restorations. If confronted with any of these situations, consider the placement of amalgam restorations in posterior deciduous or permanent teeth or referral to a pedodontist capable of sedating the patient for restorative procedures.
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