In a 2-year trial, new occlusal caries developed in 30% of control children and 20% of children who received sealants. What is the number needed to treat (NNT) with sealants to prevent one child from developing new occlusal caries over 2 years?
- Correct answer
10
-
3
-
5
-
33
This question is one of 15 in AFK practice: Prevention, infection control and ethics. Test yourself on all of them.
Practice quiz FlashcardsExplanations
The absolute risk reduction is 30% − 20% = 10% (0.10), and NNT = 1/ARR = 10 children sealed for 2 years to prevent one child from developing occlusal caries. The relative risk reduction is 33%, which is a percentage, not an NNT.
Source: Fletcher, Clinical Epidemiology: The Essentials — oneguy
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