Cant of upper teeth, asymmetric gum line, little or no deviation of chin. What causes this? What treatments are possible?(Photo)

As can be seen from the photos I have a maxillary cant (well, at least the upper teeth are canted), but there would appear to be little or no cant of the mandible, and little or deviation of the chin to the left (in addition the midlines are at different angles). Is this a regular occlusal cant, or is there something else going on? Is any surgery or orthodontistry required, or would vaneers suffice? Is this problem associated with, or likely to cause, TMJ problems?