Written by Ross W. Nash, DDS Monday, 13 February 2012 19:06
Who is the ultimate clinical challenge? A clinician and friend, who makes his living creating dental adhesives and composite resins!
Diagnosis and Treatment Planning
My patient presented to me with some serious problems and concerns, asking for help. His situation began 35 years ago following a water skiing accident. As a result of that accident, he had suffered a bilaterally fractured mandible, with numerous fractured teeth as well as a significant loss of teeth. With the recent loss of his mandibular left fixed partial denture (due to fracture of the posterior abutment), it was time for a rehabilitation of the previously delivered traditional dentistry using up-to-date ceramics and adhesive dentistry.
Following the initial examination, it was obvious that retreatment of the endodontic work previously completed on the maxillary right molar would be needed. This was accomplished by Dr. William Nudera (Chicago, Ill). The lower left bridge was removed (Dr. Larry Smith, Chicago, Ill) and the molar abutment was extracted with bone substitutes placed (Dr. Rick Diehl, Minneapolis, Minn). Following healing and cone beam diagnostics, implant placement was then planned. Our goal would be to restore function and aesthetics with an emphasis on protecting the dental-pulpal complex. This would be accomplished with immediate sealing of the dentin (for desensitization), the use of new apatite forming liners, light-assisted dual-cure resin core/block-out materials, and the creative use of self-etching adhesives and indirect primers during the final cementation phase.
The retracted facial view of the patient's clinical condition as he presented to me is shown in Figure 1. Figure 2 shows the occlusal view of the maxillary arch, and Figure 3 shows the occlusal view of the mandibular arch. At the initial appointment a full series of digital radiographs (DEXIS) was taken as well as maxillary and mandibular full-arch preliminary impressions for study models. In addition, a facebow transfer record was taken for mounting the models on a semi-adjustable articulator (Denar [Whip Mix]). An occlusal registration (GC Pattern Resin [GC America]) was taken for mounting the models in centric relation. It was determined that the plane of occlusion should be redefined but the vertical dimension of occlusion (VDO) should not be changed for this patient. At the dental laboratory, a full wax-up to ideal anatomy was fabricated. Vinyl polysiloxane (VPS) stints (Star VPS Putty [Danville Materials]) were molded over the wax-ups for fabrication of the provisional restorations later at the chair.
|Figure 1. Retracted view of the case before treatment.||Figure 2. Occlusal view of maxillary arch before treatment.|
At the preparation appointment, the mandibular anterior natural teeth were recontoured via enameloplasty. The maxillary 6 anterior teeth were prepared for lithium disilicate veneers (e.max [Ivoclar Vivadent]) and 360° laminates. An anterior occlusal registration was taken to record the existing VDO dimensions before the posterior teeth were prepared. Buildups were done on maxillary posterior teeth using a new bioactive light-cured resin-modified calcium silicate liner (Theracal [BISCO Dental Products]) followed by a dual-cure build-up material. Theracal is a flowable pulpal protectant which was recently FDA-approved as an apatite-stimulating material for use on deep-affected and caries-free dentin. A dual-cured resin core (CoreFlo DC [BISCO Dental Products]) was bonded to place with a self-etching bonding agent (All-Bond SE [BISCO Dental Products]). The posterior teeth were then prepared for zirconium oxide crowns and fixed partial dentures (bridges) (Lava [3M ESPE]).
The mandibular posterior teeth were prepared in a similar manner. A small inlay preparation was made in the mandibular third molar where some recurrent decay was found. The first occlusal registration was replaced and posterior occlusal registrations were taken. The finished preparations for the maxillary arch can be seen from the occlusal view in Figure 4, and the mandibular preparations are shown in Figure 5.
Next, final impressions were taken with a VPS impression material (Star VPS [Danville Materials]). Provisional restorations were fabricated using a bisacrylic material (Luxatemp Ultra [DMG America]) that was injected into the laboratory-fabricated VPS putty stints and placed directly over the prepared teeth.
Final Restorations Were Fabricated by the Dental Laboratory Team
A total of one 4-unit zirconium oxide bridge and 8 zirconia oxide crowns were made for the posterior areas. Six maxillary anterior laminates, one mandibular anterior crown and one inlay were fabricated using lithium disilicate. The restorations on the working models can be seen in Figure 6. All restorations were inspected and no internal or external voids or defects could be detected.
Clinical Delivery Phase
At the delivery appointment, the provisional restorations were removed and the final restorations were tried in. All margins, contacts, and contours were checked and approved.
Zirconium Oxide Restorations
Upon inspection of the zirconium oxide restorations, an indirect primer specific to metal oxides (ZPrime+ [BISCO Dental Products]) was applied in 2 thin coats, followed by air-drying. Zirconia primers offer the benefit of creating a hydrophobic seal of the zirconia milled surface in addition to providing covalent bond potential with the use of dual-cure resin cements (Figure 7).
|Figure 3. Occlusal view of mandibular arch before treatment.||Figure 4. Occlusal view of maxillary arch after preparation.|
|Figure 5. Occlusal view of mandibular arch after preparation.||Figure 6. Restorations on working model.|
|Figure 7. Zirconia oxide primer was applied to the internal aspects of the restoration.||Figure 8. A self-etching bonding agent was applied.|
The preparations were tried in successfully. Salivary pellicle was removed from the primed zirconia surface with the use of phosphoric acid etch (UniEtch [BAC]). The prepared teeth were then cleaned with plain pumice and water, and then disinfected using a chlorhexidine (CHX) disinfectant (Cavity Cleanser [BISCO Dental Products]) (Note: CHX acts as a matrix metalloproteinase enzyme inhibitor increasing the durability of the adhesive bond according to recent studies.) Cavity Cleanser was applied liberally to the prepared surfaces, allowed to dwell for 30 seconds, and then lightly air-dried. A self-etching bonding agent (All-Bond SE ) was then applied to the prepared tooth structure (Figure 8) and fully air-dried (Figure 9) to remove any solvent and water remaining. The bonding agent was appropriately light-cured for 10 seconds (Figure 10). The internal surfaces of the zirconium oxide restorations were lined (Figure 11) with a dual-cured resin cement (Duolink [BISCO Dental Products]) and seated passively (Figure 12). Excess cement can be immediately wiped clean then lightly light-cured to facilitate cleanup. Following completion of the self-cure reaction, final cleanup, and flossing can be achieved confidently without altering the bond just created.
Lithium Disilicate Restorations
Prior to try-in, the internal surface of the lithium disilicate restorations were inspected for excess salt formation produced from hydrofluoric acid-etching with salts being removed. The internal etched surfaces were treated with 2 thin coats of silane (Porcelain Primer [BISCO Dental Products]) and allowed to dwell for 30 seconds before air-drying for 30 seconds to complete the condensation reaction. Following try-in, salivary pellicles were removed with phosphoric acid etching.
|Figure 9. The bonding agent was gently dried with air.||Figure 10. Bonding agent was light-cured.|
|Figure 11. Zirconia oxide crown lined with dual-cure resin cement.||Figure 12. Crowns were passively placed.|
|Figure 13. Occlusal view of maxillary restorations in place.||Figure 14. Occlusal view of mandibular restorations in place.|
|Figure 15. Facial retracted view of the final restorations in place.|
The prepared teeth were conditioned with a benzalkonium chloride containing etchant (Uni-Etch [BISCO Dental Products]) for 10 seconds and rinsed thoroughly under high volume suction. Preparations were then disinfected using 2% CHX (as described above) and blotted moist for wet bonding. A dual-cured total-etch bonding agent (All-Bond TE [BISCO Dental Products]) was liberally applied to the prepared surfaces and air-dried to thin. The bonding agent was light-cured for 10 seconds. A light-curing resin cement (Choice 2 [BISCO Dental Products]) was placed into the internal surfaces of the laminates for the 6 maxillary anterior teeth after wetting the surfaces with an unfilled resin (Porcelain Bonding Resin [BISCO Dental Products]). After passively seating the laminates, excess cement was cleaned away and each laminate was "tacked" to place with a short burst of the curing light. Excess cured resin cement was removed and the light-curing process was completed. The lithium disilicate crown and inlay for the mandibular arch were bonded in place with the dual-cured resin cement.
Figure 13 shows the maxillary occlusal view of the final restorations in place, and Figure 14 shows the mandibular restorations. In the retracted facial view in Figure 15, the final restorations can be seen.
With today's modern restorative materials, bonding agents ,and resin cements, dentists and their laboratory and office teams can provide functional and aesthetic restorations. This case report illustrates use of some of these materials for full reconstruction of a damaged dentition.F
The author would like to thank Daniel Materdomini and the talented dental artists at daVinci Dental Studios (West Hills, Calif) for the excellent restorations created for this patient.
Disclosure: Dr. Nash reports no disclosures.
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