Determination of in vivo Element Release From Glass-Ceramics

Objectives: To determine the in vivo element release from heat-pressed all-ceramics and conventional metal-ceramics. Methods: A total of 21 healthy subjects (9 females, 12 males;18-45 years) having partial edentulism and/or loss of crown integrity who had not received any prosthetic treatment previously were included in the study. Eleven patients (5f, 6m) received Empress 2 (IvoclarVivadent,Liechtenstein) all-ceramic restorations while 10 (4f, 6m) received metal-ceramic restorations. The control group consisted of 10 healthy subjects with intact teeth. The whole saliva (10:00-12:00 a.m,centrifuge:+4°C-12.000 cycles/min for 10 min) and serum (venous) samples were collected at baseline,months 3,6 and 12 followed by the determination of Na, K, Ca, Mg (automatic analyser-Dax 48, Technicon,Japan) and Li (atomic absorption spectrophotometer-Varian Spectra AA, Australia) as well as salivary pH (pHmeter-Radiometer, Copenhagen, Denmark). The data were statistically analyzed by One-Way ANOVA, Repeated Measures ANOVA, Bonferroni and Mann-Whitney U tests.Results: Time-related changes in salivary pH for the control (6,8±0,4), all-ceramic (7±0,1) and metal-ceramic (6,9±0,5) groups were insignificant (p≥0.05). There were no significant differences (p≥0.05) in Na, Ca, Mg and Li releases from all-ceramic group in saliva within recalls while mean K release (mmol/L) was significantly higher between baseline (17,1±6,9) and 12 months (17,7±2,2) (p<0.05). Time-related differences within all element releases in saliva for the metal-ceramic group were insignificant (p≥0.05). The insignificant (p≥0.05) Li release (mmol/L) from IPS Empress2 in saliva at 12 months (0,01±0,01) was higher than baseline (0,02±0,03). The mean amounts of Na, K, Mg, Ca and Li in serum within recalls were insignificant (p≥0.05) for the all-ceramic group. A significant (p<0.05) decrease in Mg level (mmol/L) between baseline (2,3±0,3) and 6th month (1,9±0,3) in the metal-ceramic group was observed. Conclusion: All-ceramic materials could be considered safe, but not totally inert, thus further longitudinal clinical studies in wider populations are required.