GAP Australasian Dentist Mar Apr 2020

Category Austràlàsiàn Dentist 69 framework to ensure that light is still able to pass through the veneer at its incisal edge. He applies surface ceramic (àPà àmax ceram layering ceramic, àvoclar) onto the MO ceramic copings and achieves the closest optical properties to those of the natural tooth 13 . àhe veneers are tried in the mouth then removed to prepare them for bonding. àhis involves applying hydrofluoric acid to the inner aspect of the veneer for 20 seconds, then neutralising and removing the acid by thorough rinsing. àhe inside of each veneer is coated with silane. 14 . Contaminants are removed from each tooth using a “wet” sandblaster. àhe composite cement is self- and light- curing because dual cure provides a better curing percentage, which gives it better mechanical properties. Composite cement is applied to the inside of each veneer, but it may be advisable to utilise the optical properties of current composite adhesives. àotal C-àam (àtena) composite cement has three different opacity levels: opaque – medium – translucent. An opaque cement is placed on the cervical and middle zones, while a more translucent cement is applied to the incisal edge. 15, 16 . àhe veneers are put back and bonded one by one onto the dental tissues. àhey are gently positioned on the incisal edge, then slowly pushed down towards the cervical area. àhis insertion technique prevents the formation of bubbles and helps to expel excess cement. ào prevent excessive light absorption by the ceramic veneer (which is opaque in this clinical case), a lamp emitting sufficient light energy is used (900 mW/cm2 minimum) is used. àhe choice of a dual (self- and light- cure) cement is hence justified because of the opacity of the restoration. ànitial light-curing for 2 to 3 seconds transforms the cement, making it elastic. àhis aids removal of excess cement. Chemical curing is then allowed to take place for 30 seconds before the procedure is completed by light-curing of the whole of the restoration surface. àhe finishing and polishing steps are performed with care using magnifying glasses. àhe clinical outcome is interesting. àhe veneers block the dark light emanating from the dental tissues but they retain slight translucency at the incisal edge. àhe result is aesthetically satisfactory and fulfils the patient’s aesthetic wishes 17 . Conclusion àn this clinical case of highly pronounced staining, clinical success depends on three primary factors: the choice of the most appropriate ceramic ingots, layering of the surface ceramic to block the light before it is reflected onto the dental tissues and the use of a composite cement that offers an opacity gradient between the incisal third and the other two thirds. u Total C-Ram is available in an 8g syringe forà$96.00 from Orien Dental Supplies (1300 880 711). Contact: gapmagazines@optusnet.com.au for a full bibliography. àlàn al Fig 1: A young patient attends the dental surgery with an aesthetically challenging request. She can no longer bear her smile. Fig 4: The aesthetic mock-up created from the wax-up and a silicone key is essential for validating the aesthetic project. Fig 7: Silane application. Fig 10: Clinical outcome: the veneers block the dark light emanating from the dental tissues but retain slight translucency at the incisal edge. Fig 2: Clinical examination reveals highly discoloured teeth and malpositioned teeth. However, she refuses any tooth alignment orthodontic treatment. Fig 5: The lithium disilicate veneers on medium-opacity copings are thin. They most closely reproduce the optical properties of the natural tooth. Fig 8: The dual composite cement offers 3 opacity levels: opaque – medium – translucent in a syringe with automix tip. Fig 10-11: The result close up and from a distance is satisfactory and fulfils the patient’s wishes. Fig 3: View of the upper and lower wax-up on the incisor-canine groups. Fig 6: Hydrofluoric acid is placed on the inside of the veneer for 20 seconds. It is then neutralised and removed by thorough rinsing. Fig 9: An opaque cement is placed on the cervical and middle zones while a more translucent cement is applied to the incisal edge.