Selection of luting agents, part 1

The clinical success of indirect restorations is dependent on multiple factors that include preparation design, mechanical forces, restorative material selection, oral hygiene, and selection of a proper luting agent. The selection of the luting agent is dependent on the specific clinical situation, the type of restoration utilized and the physical, biologic, and handling properties of the luting agent. Although it is important to choose the best luting agent for each clinical situation, far greater variations in physical properties result from improper manipulation of a given luting agent than exist between different types of cements. One study listed loss of retention as the third-leading cause of prosthetic replacement, with failure occurring after only 5.8 years in service. The primary purpose of the luting procedure is to achieve a durable bond and to have good marginal adaptation of the luting material to the restoration and tooth. Conventional cements have always relied upon retention and resistance forms in tooth preparations; Adhesive-type luting agents offer the clinician an added advantage by bonding to the tooth structure. Three main types of conventional "cements" are commonly used, zinc phosphate and the polyelectrolyte cements polycarboxylate, and glass ionomer cements. Because of its long history of successful clinical use, zinc phosphate is considered the gold standard against which all other luting agents are compared because of its long clinical history of successful use. Currently, two additional types of luting agents have gained considerable popularity. These include the resin-modified glass ionomer cements and resin cements. The resin cement category includes light-cured, dual-cured and chemically cured agents. The purpose of this article is to discuss the ideal attributes of a luting agent and make clinical recommendations for their use.