You can chew gums to a certain limit. But over use of anything is not good just like oveethinking. You can practice more healthier ways to avoid overthinking. Proper balanced diet, exercise, meditation and staying hydrated play a key role in well being of a person.

Chewing actually helps to remove plaque from your mouth, your bad odor, increase salivation causing your mouth less prone to decay . But excessive chewing also have it's own adverse effects, it cause attrition of tooth, strain in cheek muscle and sometimes ulcers in mouth.

Actually there is no scientifically proven results of showing chewing gums relation with overthinking. Chewing gums helps to increase salivation in your mouth and chewing some gums helps to maintain the pH level of your saliva in the mouth. As well as excessive chewing and excess force in chewing may lead to attrition of enamel. Most of the chewing gums comes with either sugar or artificial sweeteners, if both of these taken more than a limit it can also be harmful to overall health.