A New and Improved Self- Adhesive Resin Cement
Thomas E. Dudney, DMD, on BISCO’s TheraCem®
As dental restorations and the materials that they are fabricated from have continued to change and improve, so too have the cements that are used to lute these restorations to teeth. The different types of dental cements include zinc phosphate, zinc polycarboxylate, glass ionomer, resin-modified glass ionomer, self-adhesive resin, and adhesive resin cements. Although adhesive resin cements are often necessary in situations that require higher bond strength, a cement that requires no special treatment of either the tooth or the restoration is simpler to use and less technique sensitive, which is why, of the categories listed above, resin-modified glass ionomer and self-adhesive resin cements are so popular.
Recently, BISCO introduced a new cement called TheraCem®, which is a self-etch, self-adhesive resin cement with some new features. Unlike other cements in the self-adhesive resin category, TheraCem provides a continuous calcium and fluoride release that offers significant benefits.1 The release of fluoride ions has long been a beneficial characteristic of glass ionomer and resin-modified glass ionomer cements, but TheraCem's additional release of calcium ions takes it a step further. In addition, TheraCem can help to generate an alkaline environment. In order for TheraCem to possess self-etching capabilities, it must initially be acidic, but it quickly transitions to an alkaline pH in a matter of minutes,2 which aids in acid neutralization. This release of fluoride and calcium ions and transition of the cement to an alkaline pH could actually help preserve the marginal integrity of a dental restoration long-term.
Other benefits of TheraCem include a high degree of conversion that ensures a higher physical strength, a gel state that facilitates quick and easy cleanup, a radiopacity that makes it easy to identify on a radiograph, an easy-to-use auto-mix syringe that provides a consistent mix every time, a universal shade that can even be used with the newer translucent zirconia restorations, and a formulation that does not require refrigeration. TheraCem may be used to cement all types of ceramic, zirconia, and metal-based restorations that do not require the extra retention and strengthening of the restorative material provided by adhesive resin cements. In addition, TheraCem contains the 10-methacryloyloxydecyl dihydrogen phosphate (MDP) monomer, which has been shown to bond to zirconia.
Currently, lithium disilicate and zirconia are the two most popular materials for the fabrication of indirect restorations, and when deciding which cement to use to lute these restorations, dentists have many excellent choices. When the high bond strengths, better retention, and strengthening of the restorative material provided by an adhesive resin cement are not required, resin-modified glass ionomers and self-adhesive resin cements are usually the options of choice. This is most likely because they are simple to use, easy to clean up, have less steps, and do not require adherence to the strict cementation protocols of adhesive resin cements while still providing some bond to the tooth structure. Plus, with TheraCem, there are the added benefits of calcium release and the ability to chemically bond to zirconia restorations. After a product evaluation of TheraCem that was conducted by the Catapult Group, 100% of the dentists who participated said that they would use this cement in their own practices.
Thomas E. Dudney, DMD
American Board of Aesthetic Dentistry
1. TheraCem continuously releases both calcium and fluoride1
2. TheraCem contains MDP, an adhesion promoting monomer that has an affinity to bond to the calcium of the tooth structure, which can generate higher bond strength
3. TheraCem's MDP containing formulation will bond to zirconia and metal substrates via the generation of a covalent bond without the use of an additional primer
4. TheraCem is specifically formulated to be clearly identified on radiographs and to allow for quick and easy removal of excess cement
1. Gleave C, Chen L, Suh B. Calcium & fluoride recharge of resin cements. Dent Mater. 2016;32:e26.
2. Chen L, Gleave C, Suh B. New self-adhesive re-sin cement with alkaline pH. J Dent Res. 2017;96 (A):286.