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CAD/CAM - international magazine of digital dentistry

10 I I CE article _ practical lessons in CAD/CAM and the provisionals did not show signs of maloc- clusion, such as fracture or accelerated wear. His central incisors were hitting just inside the wet-dry line of the lower lip during “F” sounds. During “S” sounds,theclosestspeakingspace,thepatient’smax- illary and mandibular anterior teeth did not touch. Once verified, a vinyl polysiloxane (VPS) impres- sion of the temporaries was made along with a bite registration. At this point, centric relation was equal to maximum intercuspal position (MIP). The E4D Dentist System system’s clone feature copied the occlusion of the provisionals exactly (Fig. 14). Thesoftware,DentalLogic,allowsthecliniciantosu- perimposetheprovisional“clone”modelovertheresto- rationdesigntodetermineaccuracy(Fig.15).Oneofthe most powerful features of the software is the ability to turntheclonemodelclearandanalyzehowaccurately the software has copied the anatomy and occlusion. The accuracy of this is within microns and an intuitive colourmapdisplaysthediscrepancythatexistsbetween thetemporariesandthefinalcrowndesign(Fig.15). The restorations were milled and prepared by etchingwith4.9%hydroflouricacidfor20secondsand silanatingfor60seconds.Thetoothwasthenpumiced, curing solution applied and cured for 20 seconds. The restorationwasthenreadyforcementation. The occlusion was identical to the provisional and thus no adjustments were needed on the day of de- livery. With the option now to use IPS e.max HT, this casehadabetteraestheticresultbecausetheLTblock appears slightly monochromatic and opaque. _Summary Dental patients typically want tooth-coloured in- directrestorations;andwiththenewerceramicsthat are available for chairside milling, the same high- quality ceramic restorations that labs are producing can be fabricated in a single appointment. With a chairside CAD/CAM system, large, tech- nique-sensitive and inferior direct resins require less treatment planning because milled IPS e.max onlays can take their place. Chairside CAD/CAM dentistry is not the only way to provide patients with high-qual- ity restorations, but it certainly is the most exciting from both a clinician’s and patient’s viewpoint. Multiple-visit, single-unit restorations; singleunit temporaries; difficult resins; expensive monthly fab- rication fees; and bonding restorations after weeks of contamination with temporary cement and saliva is routine for most dentists who have not invested in CAD/CAM technology. The old adage “what you don’t know you don’t miss” holds true._ Editorial note: A complete list of references is available fromthepublisher. Fig. 15_The E4D Dentist System software, DentaLogic, enables the clinician to superimpose the temporary “clone” model over the restoration design to determine accuracy. Fig. 16_Restorations are milled out of B1 e.max CAD LT, prepared and seated. CAD/CAM 3_2013 Dr Wally Renne,DMD,is a 2003 graduate of the College of Charleston and a 2008 graduate of the Medical University of South Carolina (MUSC) College of Dental Medicine.He is active in undergraduatedentaleducation andholdsafulltimefacultypositioninthedepartment of oral rehabilitation at MUSC.He is the course director for CAD/CAM technologies and ceramics and runs the E4D CAD/CAM clinic at MUSC. Dr Renne maintains an active general dentistry practice utilizing both the CERECAC and E4D Dentist System.His special interests in patient treatment include advances in CAD/CAM dentistry, adhesive dentistry and conservative dentistry. He is active in dental research and currently has a patent pending for a new dental adhesive that is permanently antimicrobial and has revolutionary bond durability components that prevent enzyme degradation of the hybrid layer. This bonding agent may prevent recurrent caries and bond breakdown in the long term. CAD/CAM_about the author Fig. 16Fig. 15