3M ESPE RelyX Unicem Self-Adhesive Resin Cement (7 yr) (2011 PPL)

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7-Year Clinical Performance

Consultants' Comments

• “Using RelyX Unicem, I am confident in getting good retention.”
• “We use RelyX Unicem more often than any other cement in the clinic.”
• “I love the new post cementation tips used with RelyX Unicem.”
• “In 7 years of using RelyX Unicem, it really has proven itself.”

Description

3M ESPE RelyX^TM Unicem Self-Adhesive Resin Cement is a dual-cured resin cement. It is self adhesive, requiring no separate etching, priming or bonding. The cement is filled 72% by wt and contains fluoride. RelyX Unicem is available in two capsule sizes (Aplicap and Maxicap) in shades A1, A2, A3 Opaque, white opaque, and translucent. RelyX Unicem is also available in a paste/paste formulation delivered through the Clicker. RelyX Unicem is indicated for the cementation of silica-based and high-strength ceramics, PFM and metal restorations, crowns, bridges, inlays, onlays, and endodontic posts. It is also recommended for cementing CAD/CAM restorations. Working time is 2 minutes for the Aplicap and the Clicker and 2.5 minutes for the Maxicap. The Aplicaps have enough material to cement one or two restorations, while the Maxicaps have enough material for up to three to six restorations. This product received a 99% clinical rating.

Clinical Evaluation Protocol

More than 6000 restorations have been cemented with RelyX Unicem over the past 7.5 years at Enspire Dental by four dentists. The restorations include ceramic inlays, onlays, bridges, PFM crowns, posts, and CAD/CAM restorations (Figure 1). 1,458 restorations were available for recall over a six-month period (Figure 2).

Categories evaluated at recall included: postoperative sensitivity, marginal discoloration, and retention. Each category was rated on a scale of 1-5: 1=poor, 2=fair, 3=good, 4=very good, 5=excellent.

Clinical Observations

Postoperative Sensitivity
Since its introduction, RelyX Unicem has had very few reported instances of postoperative sensitivity (Figure 3). The postoperative sensitivity was 1.1% of the seated restorations and usually occurred shortly after cementation. In most cases, the sensitivity subsided within weeks after cementing the restoration.

Marginal Discoloration
Ninety-four percent of the restorations recalled showed no marginal discoloration (Figure 3). Discoloration at the margin was exhibited by graying at the margin of ceramic restorations and, in rare cases, resulted in darkening of the entire restoration, making it very noticeable and unattractive. Graying at the margins was observed in 6% of the restorations. 1.3% of these restorations needed to be replaced because of the graying, while 4.7% were not replaced. The rate of microleakage of restorations cemented with RelyX Unicem is comparable to restorations cemented with 5th- and 6th-generation bonding agents and corresponding light- or dual-cured resin cements.

Debonding
A 2.4% debonding rate was documented in the recalled restorations over the seven- year evaluation period (Figure 3). Among the 1458 recalled restorations cemented with RelyX Unicem, 32 restorations needed to be recemented. Four of these restorations fractured or were lost and had to be redone. Upon examining the internal surfaces of the debonded restorations, it was observed in many of the cases that the cement had adhered to the restoration and not the tooth. Most of the teeth that supported these restorations exhibited various levels of graying or blackening of the surface.

Summary

RelyX Unicem has proven to be a reliable self-adhesive resin cement over the seven-year recall period. It is the only cement that has been documented by THE DENTAL ADVISOR over this length of time and continues to perform extremely well.