Sign into your profile on the Teamviewer.com page and then go to Edit Profile in the top right. You can click active logins on the left tabs and delete all or specific active logins. To my knowledge this will require a new add device pop up the next time someone tries to use that device. Facebook and several other social services have this same feature to see approximately where people are logged in at and you can kick off bad connections and create a new password to just be safe.
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