Final answer:
The concern about saliva in dentistry is true because it can be contaminated with blood during dental procedures, potentially leading to the spread of infections such as dental caries and systemic diseases.
Step-by-step explanation:
The concern for saliva in dentistry is indeed valid because it can often be contaminated with blood, particularly during dental procedures. This contamination poses a risk of transmitting infections, as saliva can harbor microbes that are harmful to both dental and general health. Oral microbes such as Streptococcus can cause dental caries and potentially spread throughout the body, leading to systemic infections such as endocarditis or contributing to atherosclerosis if they enter the bloodstream. Proper hygiene protocols in dental practice are essential to manage these risks.