Final answer:
The most appropriate restorative material for an 86-year-old patient with a cavitated lesion who wishes to avoid mercury is a resin-modified glass ionomer. This material does not contain mercury and releases fluoride to help protect against decay.
Step-by-step explanation:
An 86-year-old patient with poor oral hygiene has a cavitated lesion with active caries on the vestibular root surface of a maxillary posterior tooth and has expressed a desire to avoid mercury. Given this preference, resin-modified glass ionomer is the most appropriate restorative material. Unlike amalgam, which is composed of approximately 50% mercury, a resin-modified glass ionomer is a mercury-free material that also releases fluoride, which can further protect the teeth from decay. Dental amalgams have been traditionally used due to their durability and cost-effectiveness, but concerns over mercury toxicity have led many patients to prefer alternative, mercury-free dental materials. Furthermore, resin-modified glass ionomers bond chemically to the tooth structure and can be particularly useful in situations where moisture control is difficult, as may be the case with root surface lesions.
Resin-modified glass ionomer is a dental material that contains a combination of glass ionomer and resin composite components. It is ideal for this situation because it is tooth-colored, adheres well to the tooth surface, and releases fluoride to help prevent further decay.