CAD/CAM - international magazine of digital dentistry

Fig. 5_The preparation of tooth #13, surrounding dentition and soft tissues are sprayed with CAD/CAM scanning powder prior to scanning. Fig. 6_The IPS e.max CAD lithium disilicate crown after milling in CEREC MC XL. Figs. 7 & 8_The lithium disilicate crown is tried in the patient’s mouth to confirm fit, contour and anatomical harmony prior to firing. Fig. 9_Tobacco stains are placed on the crown to mimic the surrounding dentition,andthecrowniscrystallised. Fig. 10_Luting composite is placed on the internal surfaces of the crown. I 11 case report _ crown fabrication I CAD/CAM 3_2011 The CEREC MC XL system (Sirona) is a powerful and accurate low-noise chairside CAD/CAM milling system that offers simplicity and efficiency for pro- cessingsingle-toothrestorationsinsixminutesand quadrant restorations in three to four minutes in a single appointment.5–7 The CEREC MC XL demonstrates precision and accuracy within the range of +/- 25 µ, and the 7.5 µ milling resolution creates restorations with im- proved fit and smoother surfaces.5–7 Additional features include automatic software downloads, simple display guides and network connectivity, and the milling chamber design enables easy block clamping without tools.5–7 _Material considerations To address CAD/CAM material concerns, manu- facturers have developed new ceramic materials that provide improved strength and aesthetics.5 These newer ceramics withstand CAD/CAM pro- cessing without chipping or fracturing and can be brought to full contour during milling to improve fit and function.5 Dentists can choose adhesive bondingorconventionalcementationwhenseating theserestorations,whichensuresthatcaserequire- ments are met.5 Improvements to cementation and adhesive systems have also enabled dentists to provide a strong bond between the restoration and underlying tooth substrates.1,4 _IPS e.max CAD Composed of 70 % by volume needle-like crys- tals in a glassy matrix, lithium disilicate glass- ceramic (IPS e.max, Ivoclar Vivadent) offers many improvements to previous generations of ceramic materials.8 Availableinapressableformat(IPSe.max Press) or for CAD processing (IPS e.max CAD), the material demonstrates strength values between 360 (Press) and 400 MPa (CAD).8 IPSe.maxalsodemonstrateslifelikeopticalqual- ities that enable dentists to create highly aesthetic and naturally appearing restorations in a variety of cases.8 Theversatilematerialisindicatedforanterior and posterior restorations, including thin veneers (0.3 mm), minimally invasive inlays and onlays, partial crowns and crowns, implant superstruc- tures, three-unit anterior/premolar bridges (press only), and three-unit bridges (zirconium-oxide- supported IPS e.max CAD only).8 _Case presentation A 53-year-old male patient presented after undergoing recent endodontic treatment on tooth #13 (Fig. 1) and was unhappy with the tooth’s ap- pearance. Along with decay on the adjacent denti- tion, tobacco stains were also present because the patient was a smoker (Fig. 2). Although the patient requested that treatment be confined to only tooth #13, after a routine head, neck and oral cavity examination, the patient was informed of multiple treatment needs and advised that a comprehensive treatment plan should be started as soon as pos- sible. Treatmentplan Thepatientbroughttotheofficetheendodontic report from his other clinician, advising that a good prognosis was expected from his endodontic treat- Fig. 8 Fig. 6 Fig. 10 Fig. 5 Fig. 7 Fig. 9