Consultants’ Comments
- “RelyX Unicem has really proven to be an excellent choice for the cementation of a variety of restorations”
- “It is definitely the most widely used cement in our practice”
- “When I first started using RelyX Unicem, I was not sure of how well it will perform over time. After six years, its performance has been exceptional.”
- “As an assistant RelyX Unicem has been my first choice – it is just so easy to use and clean up.”
Description
3M ESPE RelyX™ Unicem Self-Adhesive Universal ResinCement (3M ESPE) is a dual-cured resin cement. It is self-adhesive, requiring no tooth surface preparation such as etching, priming or bonding. The cement is filled 72% by weight 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 cement is also available in a paste/paste formulation delivered by Clicker™ Dispenser in shades A2 universal, A3-opaque and translucent. RelyX Unicem cement is indicated for the cementation of metal, PFM, etchable and high strength ceramic and laboratory composite crowns, bridges, inlays, onlays, and endodontic posts. It is also recommended for cementing CAD/CAM restorations. It is not recommended for the cementation of veneers. Working time is 2 minutes for the Aplicaps and the Clicker and 2.5 minutes for the larger Maxicaps. The Aplicaps have enough material to cement one to two restorations, whereas the Maxicaps have enough material for three to six restorations. This product received a 99% clinical rating.
Clinical Evaluation Protocol
- More than 5600 restorations have been cemented with RelyX Unicem over the past 6.5 years. These restorations include all-ceramic inlays, onlays, crowns, bridges; PFM crowns and bridges; posts, and CAD/CAM restorations (Figure 1).
- 1739 restorations were available for recall. See Figure 2 for the yearly distribution of the 1739 restorations recorded.
- Characteristics evaluated at recall include:
- Postoperative sensitivity
- Discoloration at margins
- Debonding
Figure 1
Figure 2
Clinical Observations
Postoperative sensitivity
Since its introduction and subsequent yearly recall RelyX Unicem has had very few instances of postoperative sensitivity. The postoperative sensitivity was less than 1.2% of the seated restorations and usually occurred in the first year, post cementation (Figure 3). In most cases, the postoperative sensitivity was of short duration.
Discoloration at margin
Discoloration at the margins is exhibited by graying or microleakage at the margin of all-ceramic restorations and in rare cases, the graying results in darkening of the whole restoration making it unattractive. Graying at the margins was noted in 5.3% of the restorations and it seemed to be time related (Figure 3). 1.3% of the restorations needed to be replaced as a result of the graying. Several factors can contribute to microleakage:
- Improper isolation during cementation
- Bruxism compromising the bond between the cement and the tooth, especially at the cervical margin.
- Thermal cycling – as the patient ingests hot and cold foods or drinks it results in weakening of the bond to the tooth or the restoration allowing the egress of fluid and bacteria and causing graying at the margin. 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 low debonding rate of 2.6% was documented over the six-year evaluation period. Among 1739 recalled restorations cemented with RelyX Unicem, 46 required re-cementation (Figure 3). These included 24 ceramic onlays, 10 ceramic crowns, and 12 PFM crowns. Of the 24 ceramic onlays that debonded, 12 had little direct retention. In five of these debonding cases, a portion of the tooth fractured.
Figure 3
Summary
3M ESPE RelyX Unicem Self-Adhesive Universal Resin Cement has proven to be excellent and reliable self-adhesive resin cement in the six years since its introduction.
