Restoration of Anterior Dental Erosion with a Combination of Veneers and Crowns: A 3-Year Case Report.

This report describes the conservative management of a 40-year-old female patient with smooth, eroded facial enamel affecting her maxillary anterior and some posterior teeth. Using conventional enamel bonding, pressed leucite-reinforced laminate veneers were used to restore the length, contour, and esthetics of the maxillary right canine, as well as of the right lateral and both central incisors; at the same time, it was necessary to restore the maxillary left lateral incisor, canine, and first premolar of the same quadrant with all-ceramic crowns of the same material. The patient has been followed for 3 years and demonstrates a good esthetic outcome with no shade discrepancy between the two types of restoration. Apparently, the tooth structure, though eroded, was able to provide an adequate bonding substrate for these adhesive restorations.

Tensile bond strength of an adhesive resin cement to different alloys having various surface treatments.

STATEMENT OF PROBLEM: The ability of a resin cement to bond to a restorative alloy is critical for maximal crown retention to nonideal preparations. Surface treatment and metal type may have an important role in optimizing resin-to-metal strength. PURPOSE: The purpose of this study was to examine the effect of surface pretreatment on the tensile strength of base and noble metals bonded using a conventional resin cement. MATERIAL AND METHODS: Cylindrical plastic rods (9.5 mm in diameter), cast in base (Rexillium NBF) or noble metal (IPS d.SIGN 53), were divided into rods 10 mm in length (n=10-12). Specimens were heated in a porcelain furnace to create an oxide layer. Test specimens were further subjected to airborne-particle abrasion (50-microm Al(2)O(3) particles) alone or with the application of a metal primer (Alloy Primer). Similarly treated rod ends were joined using resin cement (RelyX ARC), thermocycled (x500, 5 degrees -55 degrees C) and stored (24 hours, 37 degrees C) before debonding using a universal testing machine. Debond strength and failure site were recorded. Rank-based ANOVA for unbalanced designs was used to test for significant interaction (alpha=.050). Each pair of treatments was compared separately for each metal (Bonferroni-adjusted significance level of .0083, overall error rate for comparisons, .05). The 2 metals were compared separately for each of the 3 treatments using an adjusted significance level of .017, maintaining an overall error rate of .05. A multinomial logit model was used to describe the effect of metal type and surface pretreatment on failure site location (alpha=.05). RESULTS: Interaction between metal type and surface pretreatment was significant for stress values (P=.019). Metal type did not significantly affect tensile bond strength for any of the compared surface pretreatments. Metal primer significantly improved tensile bond strength for each metal type. Most failures tended to occur as either adhesive or mixed in nature. CONCLUSIONS: Metal primer application significantly enhanced tensile bond strength to base and noble metal. No significant differences in tensile strength were found between alloys. Differences in failure site incidence were found to be related to metal type and surface pretreatment.

Effect of metal type and surface treatment on in vitro tensile strength of copings cemented to minimally retentive preparations.

STATEMENT OF PROBLEM: Due to the potential lack of ideal preparation form, the type of alloy and its surface pretreatment may have clinically relevant correlations with the retentive strength of castings to minimally retentive preparations. PURPOSE: The purpose of this study was to evaluate the effect of alloy type and surface pretreatments of base and noble metal copings on their tensile strength to minimally retentive preparations. MATERIAL AND METHODS: Minimally retentive, standardized crown preparations were made on recently extracted human third molars (n=68). Noble (IPS d.SIGN 53) and base metal (Rexillium NBF) copings were fabricated. All copings received heat treatment for oxide formation. Three experimental groups were then developed for each metal type (groups ranging from 10 to 12 specimens each): oxide only, airborne-particle abraded, or metal-primed. Copings were cemented using a self-adhesive universal resin cement (RelyX Unicem) and were thermal cycled (500 cycles between 5 and 55 degrees C) and stored (24 hours, 37 degrees C) before debonding using a universal testing machine. Frequency of debond location was compared among specimen groups. A 2-way ANOVA was used to test for interaction between the metal type and surface treatment, and, if no significant interaction was found, to test the main effects for metal type and surface treatment (alpha=.05). A multinomial logit model using the likelihood ratio test was used to describe the effect of metal type and surface treatment on failure site location (alpha=.05). RESULTS: The 2-way ANOVA indicated no significant influence of any factor on debond load: metal type (P=.885), surface treatment (P=.555), or their interaction (P=.644). The multinomial logit statistical model showed that noble metals and metal primers significantly (P<.05) shifted debond failures to occur more frequently at the resin/tooth interface or within the tooth itself. CONCLUSIONS: Neither metal type nor surface pretreatment affected bond strength. However, alloy type and surface treatment affected site of debond location. (J Prosthet Dent 2007;98:199-207).