Front Tooth Dropped Down Lower (Do to Periodontal Issues?) What are the options? (photos)

I had perio disease, got deep cleaning. I get regular cleanings every 3 months. My gums & teeth are relatively healthy now. It's been 2 years since I had any problems. Noticed that over the past 6 mths one of my front teeth is dropping down. The 2 front teeth used to line up. Now when I smile slightly you only see 1 tooth. I have no missing teeth on the bottom. Why is this happening? What options are there to fix this? I was thinking of having my dentist file the tooth. Is this a good/bad idea & why?