Final answer:
All topics are appropriate except for the importance of oral hygiene.
Step-by-step explanation:
Based on the target group, all of the following may be appropriate topics to cover:
- Mouthguards for sports
- Effects of tobacco on oral health
- Orthodontic treatment options
The exception would be Importance of oral hygiene. Since the coach has already invited the dental hygienist to make a presentation on preventing health problems in the oral cavity, the importance of oral hygiene is already implied and doesn't need to be a separate topic.