The biocompatibility trend of glass ionomer in terms of cytotoxicity over time is best described as:

• A. mild cytotoxicity initially, decreasing over time
• B. no cytotoxicity at any time
• C. cytotoxicity increases over time
• D. cytotoxicity remains constant

Answer: (A)

Glass ionomer cements can show a transient cytotoxic response when first placed because the fresh material is acidic and releases ions during the initial setting phase. As the material sets, the acidity decreases and the rate of ion release stabilizes, so the initial mild cytotoxic effects diminish over time. This makes the trend best described as mild cytotoxicity initially, decreasing as time passes. In contrast, options suggesting no cytotoxicity at all, increasing cytotoxicity over time, or a constant level do not align with the way glass ionomer interacts with tissues during maturation.