Final answer:
Glass ionomer cement is the least irritating dental cement.
Step-by-step explanation:
The least irritating dental cement among the options provided is Glass ionomer cement.
Glass ionomer cement is known for its biocompatibility, which means it is less likely to cause irritation or adverse reactions in the oral cavity. It is made from a combination of glass powder and organic acid.
Other dental cements mentioned in the options, such as zinc phosphate cement, polycarboxylate cement, and composite resin cement, may have different levels of irritation potential based on the individual's sensitivity, but glass ionomer cement is generally considered to be the least irritating.