Yes. This might be a compensable consequence. See http://www.wcwebzine.com/a-z/compensableconsequences.htm
But to get this covered, your Primary Treating Physician needs to recommend a dental consultation.
Workers Compensation in most states is generally responsible for the initial injury and anything that flows from that injury. I would not expect them to agree that this is related and believe you would probably need good medical reports from one or more of your drs saying so to get them to accept it without having to go to a hearing. There are many good Calif attys that are on here so I would suggest that you consider talking to one of them about the case and what medical evidence would be required.
If this information has been helpful, please indicate by providing feedback that the answer was either "helpful" or "best answer" as appropriate. Legal Disclaimer: Mr. Connell is a Colorado attorney licensed in only that state. The response herein is not legal advice and does not create an attorney/client relationship. The response is in the form of legal education and is intended to provide general information about the matter within the question.
Two things have to happen for "workman comp" to take responsibility for gums: (1) The Primary Treating Physician has to CONCLUDE that the meds are the primary cause of the gum ailment (which -- typically but not always -- follows a dentist reporting the to PTP he finds gum disease from chronic medication use), and then (2) Your attorney amends your application to show the MOUTH injury.
EXPECT the Insurer to deny this. Don't take it personally. Do expect to go get a Qualified Medical Evaluation in dental medicine. IF that QME dentist agrees with your Primary Treater, the insurer will then likely accept responsibility (and provide the bare minimal dental treatment). If that QME dentist says it's not an industrial condition, then you go to trial on your gums.