An overview of treatment considerations for esthetic restorations

An overview of treatment considerations for esthetic restorations: A review of the literature
Steven Judd Sadowsky, DDSa School of Dentistry, University of Southern California, Los Angeles, Calif
Controversy persists regarding the treatment planning criteria for esthetic restorations. This article reviews the literature regarding the biocompatibility, marginal adaptation, color matching,patient selection, technique sensitivity, and mode and rate of failure of tooth-colored restorations. A Medline search was completed for the period from 1986 to 2006, along with a manual search, to identify pertinent English peer-reviewed articles and textbooks. The key words used were amalgam, posterior composite resin, ceramic inlays/onlays, CEREC, porcelain laminate veneers, all-ceramic crowns, andall-ceramic fixed partial dentures. (J Prosthet Dent 2006;96:433-42.)

T

he demand for tooth-colored restorations has grown considerably during the last decade.1 This phenomenon has been both a bane and a boon to the dental profession. Rush-to-market products, media-driven treatment plans, as well as dentists eager to please, have formed a disquieting triad with little regard for therisk/benefit calculus of dental rehabilitation. On the other hand, new materials wedded to precise techniques have emerged to blur the interface between biologic and artificial structures.2 For example, dentin is now understood as a biological composite of a collagen matrix, which is highly filled with nanometer-sized apatite crystals.3 Demineralizing the collagen fibrils and filling the voids with resin tags canresult in a hybrid or a true biopolymer. However, successful adhesion can be highly technique and substrate sensitive, often hinging on proper material and patient selection.4 Evidence-based dental research offers a dispassionate reference for the applicability, procedures, and prognosis of tooth-colored restorations. To further that aim, this literature review investigated the biocompatibility,marginal adaptation, color matching, patient selection, technique sensitivity, and mode and rate of failure of esthetic restorations from a search of peerreviewed English dental literature from 1986 to 2006, using Medline as well as a manual search of pertinent dental textbooks. Key words used were amalgam, posterior composite resin, ceramic inlays/onlays, CEREC, porcelain laminate veneers,all-ceramic crowns, and all-ceramic fixed partial dentures.

REPLACEMENT OF SILVER AMALGAM RESTORATIONS
The esthetic revolution began in the 1970s, coincidentally, with the observation that mercury vapor was released from amalgam, especially during the process of mastication, and that this vapor could be inhaled.5 In fact, mercury toxicity has become a compelling
Presented before the Academy ofProsthodontics Annual Meeting, San Francisco, Calif, May 2006. a Associate Clinical Professor.

rationale for replacing amalgam restorations with tooth-colored materials, despite a lack of consensus due to conflicting studies.6-17 Flaws in research methodology have been cited by both proponents and detractors of amalgam restorations.5,9,16 However, recently, a 7-year randomized clinical trial wascompleted involving 507 children, 8 to 10 years old.18 Half of the subjects were treated with amalgam restorations, and the others were restored with composite resin. There were no statistically significant differences in measures of memory, attention, visuomotor function, or nerve conduction velocities for the amalgam and composite resin groups over 7 years of follow-up. Starting at 5 years afterinitial treatment, the need for additional restorative treatment was approximately 50% higher in the composite resin group. Furthermore, Ritchie et al19 completed a psychomotor survey of 180 dentists and unmatched controls after analyses of amalgam surfaces and urine, hair, and nail specimens. The findings revealed that the dentists, in fact, had 4 times the concentration of urinary mercury than the...