Final answer:
A dental hygienist should further question the client about signs of serious dental infections, their dental history concerning fillings, oral hygiene practices, and any health changes that might affect saliva production.
Step-by-step explanation:
In considering the client's complaint of "a nagging discomfort and pressure around the top back teeth and occasional dryness of my mouth," a dental hygienist should further question the client about symptoms such as inflammation and erosion of gums, bleeding, halitosis, and erosion of cementum, which could indicate serious infections such as acute necrotizing ulcerative gingivitis (trench mouth), a severe periodontitis. The hygienist should also inquire about the client's dental history, including any fillings, as thermal stress can cause fillings to expand differently from tooth enamel creating discomfort. Given that certain bacteria can cause damage to the teeth and lead to infections, asking about the client's oral hygiene practices and any recent changes in health or medication, which could affect saliva production and lead to dry mouth, is also crucial.