Partner Magazine logo 10

17 CASE STUDY Bonded, fixed temporary dentures offer many advantages here: • The greatest acceptance by the patients • No functional impairment whatsoever • Immediate loading after the surgical procedure • Compliance-independent But there are also disadvantages: • Poor repairability and modifiability • High risk of treatment for outside patients, as other dentists, especially inexperienced dentists are soon overstretched with a repair • Risk of therapy delay due to very good esthetics and function Material and method Fixed temporaries can be used anywhere for small and medium bridge spans with up to four replaced teeth where there is no free-end situation. The construction as an extension bridge with one attached oral-occlusally reduced pontic is also quite possible. Alongside the bridge statics, the degree of loosening and particularly the surface of the potential bridge abutments are of importance. The ability to bond the surfaces and the bridge abutments available are decisive for the overall construction of the temporary. Bonded temporaries are statically dependent on at least one, preferably two or more, bridge abutments. With the exception of interim implants or prosthetic immediate loading of final implants, fixed temporaries are bonded with remaining teeth or prosthetic restorations. The resilience of this bond to the natural teeth is greatest with intact dental enamel [1,3,8]. Technical surfaces can also be used for adhesive bonding, although with significant impairment to the resilience of this bond [2,5]. In our implantological practice, the construction of a fixed bonded Maryland bridge with a metal or more recently a zirconium framework has proven very successful. We have successfully applied newer materials, such as zirconium oxide or milled composite, but recognized various drawbacks. With the exception of zirconium oxide Maryland bridges in the anterior region, the cast Maryland bridge is our standard solution today for temporary gap closure. The Maryland bridge Statically more resilient constructions are necessary for large span temporary bridges, especially in the posterior region. Metal frameworks made of cobalt- chrome-molybdenum cast alloy have become established for this purpose. The design of the clasp elements on the bridge abutments is solely responsible for the resilience and esthetic acceptance by the patient. Dark gray metal must, under no circumstances, be visible, especially for front teeth bridges. For metal-reinforced bridges, this has led to the development of very thin, but, at the same time, extensive clasp elements or preferably clasp shells. After bonding with the abutment teeth, these clasp shells are completely coated with composite and are thus no longer identifiable as clasp elements. Further condition can be performed on both sides of the clasp shells [2,5,6], but both sides must be blasted in the lab and must not be polished. Following the try-in in the patient's mouth, the bonding elements are degreased on both sides and are prepared with a metal primer (GC). The vestibular clasp parts must also be coated with a metal opaquer (GC) in the visible area to mask the dark gray metal color. As these metal primers are only available in a very light ivory shade, we have latterly darkened the primer ourselves with brown or yellow composite paining color. This can either be prepared outside the mouth or simultaneous with bonding the whole Maryland bridge (Figs. 2 and 3) . Bonding the clasps is performed with a tooth-colored compomer, e.g. RelyX Unicem from 3M/Espe [9,10]. This is applied to the inside of the clasps and the bridge is then brought into position. The natural dental enamel must never be conditioned with etching and/or a bonding system. The subsequent layering of the vestibular clasps with composite would be permanently bonded with the enamel and would have to be removed laboriously using a grinding technique (Figs. 4 and 5) . The vestibular shaping of the composite pontic should be significantly overex- tended buccally by the dental lab (Fig. 6). Only then can a unified tooth inclination be achieved, together with coating of the anterior, vestibular clasp shells (Fig. 7) . For technical surfaces, such as ceramic or metal, we also attempt to build up an adhesive bond here. A ceramic surface is etched for two minutes with hydrofluoric acid, degreased with alcohol, dried and then chemically prepared with silane (Monobond-S 2x), bonded and UV cured. Fig. 4: With the aid of a rubber dam, the ideal conditions are created to keep the area dry to bond the bridges. Fig. 6: The pontic is overextended towards the vestibular. Fig. 5: The clasps bonded with compomer are fully coated with tooth-colored composite.