Er:YAG laser debonding of porcelain veneers

摘要

The removal of porcelain veneers using EnYAG lasers has not been previously described in the scientific literature. This study was designed to systematically investigate the efficacy of an Er: YAG laser on veneer debonding without damaging the underlying tooth structure, as well as preserving a new or misplaced veneer.rnInitially, Fourier Transform Infrared Spectroscopy (FTIR) was used on flat porcelain veneer samples (IPS Empress Esthetic; Ivoclar Vivadent, Amherst, NY) to assess which infrared laser wavelengths are transmitted through the veneer. Additionally, FTIR spectra from a veneer bonding cement (RelyX Veneer Cement Al; 3M ESPE, St. Paul, MN) were obtained. While the veneer material showed no characteristic water absorption bands in the FTIR, the bonding cement has a broad H_2O/OH absorption band coinciding with the ER:YAG laser emission wavelength. Consequently EnYAG laser energy transmission through different veneer thicknesses was measured. The porcelain veneers transmitted 11 - 18 % of the incident Er:YAG laser energy depending on their thicknesses (Er:YAG laser: LiteTouch by Syneron; wavelength 2,940 nm, 10 Hz repetition rate, pulse duration 100 us at 133 mJ/pulse; straight sapphire tip 1,100 um diameter; Syneron, Yokneam, Israel). Initial signs of cement ablation occurred at approximately 1.8 - 4.0 J/cm2. This can be achieved by irradiating through the veneer with the fiber tip positioned at a distance of 3-6 mm from the veneer surface, and operating the EnYAG laser with 133 mJ output energy.rnAll eleven veneers bonded on extracted anterior incisor teeth were easily removed using the EnYAG laser. The removal occurred without damaging underlying tooth structure as verified by light microscopic investigation (Incident Light Microscope Olympus B 50, Micropublisher RTV 3.3 MP, Image Pro software, Olympus). The debonding mainly occurred at the cement/veneer interface. When the samples were stored in saline solution for 5 days and/or an air-water-spray was used during irradiation, there was a high chance that the veneer would fractured during debonding. However if samples were not stored in water and only air spray was used, 75% of the veneers could be removed without any fracture.rnThe use of an Er: YAG laser can be effective in not only debonding porcelain veneers and preserving tooth structure, but also in maintaining veneer integrity.