Chemical durability and microhardness of dental ceramics immersed in acidic agents.
OBJECTIVE
To evaluate the microhardness and surface elemental compositions of ceramics immersed in acidic agents.


METHODS
Thirty-five ceramic disc specimens were made from each of four types of ceramic (VMK 95, Vitadur Alpha, Empress Esthetic and IPS e.max Ceram). Before immersion, baseline data of Vicker's microhardness and elemental composition were recorded. Four groups of discs (seven per group) were then immersed in acidic agents (citrate buffer solution, pineapple juice and green mango juice) and deionized water (as a control) for 168 h at 37 degrees C. One group was immersed in 4% acetic acid at 80 degrees C for 168 h. After immersion, specimens were evaluated and data were analyzed using two-way ANOVA with repeated measurements and a paired t-test at a significance level of 0.05.


RESULTS
The microhardness values of four types of ceramic significantly decreased after being immersed in acidic agents (p < 0.05). The elemental compositions of ceramics mainly comprise silicon, aluminium and potassium. These compositions also decreased after immersion (p < 0.05).


CONCLUSIONS
The acidic agents used in this study affected the microhardness and elemental dissolution of ceramics. The main elemental compositions of ceramics (silicon, aluminium and potassium) decreased after being immersed in acidic agents.
Kukiattrakoon
Boonlert
B
Department of Conservative Dentistry, Faculty of Dentistry, Prince of Songkla University, Hat Yai, Songkhla, Thailand. boonlert.k@psu.ac.th
Hengtrakool
Chanothai
C
Kedjarune-Leggat
Ureporn
U
D019342:Acetic Acid / Q000737:chemistry; D000143:Acids / Q000737:chemistry; D000535:Aluminum / Q000032:analysis; D000537:Aluminum Oxide / Q000737:chemistry; D000538:Aluminum Silicates / Q000737:chemistry; D031230:Ananas; D001031:Apatites / Q000737:chemistry; D001628:Beverages; D002021:Buffers; D019343:Citric Acid / Q000737:chemistry; D003776:Dental Porcelain / Q000737:chemistry*; D006244:Hardness; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007101:Immersion; D031022:Mangifera; D008422:Materials Testing; D011188:Potassium / Q000032:analysis; D017680:Potassium Compounds / Q000737:chemistry; D012825:Silicon / Q000032:analysis; D012995:Solubility; D013052:Spectrometry, X-Ray Emission; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000737:chemistry
D000143:Acids; D000538:Aluminum Silicates; D001031:Apatites; D002021:Buffers; C508050:IPS e.max Press; C075815:IPS-Empress ceramic; D017680:Potassium Compounds; C483027:vitadur alpha; D014867:Water; D003776:Dental Porcelain; C016447:feldspar; C078519:leucite; D019343:Citric Acid; D000535:Aluminum; D000537:Aluminum Oxide; C025105:fluorapatite; D019342:Acetic Acid; D011188:Potassium; D012825:Silicon