If an employer offers an HSA and also offers dental coverage, can the services not covered by the dental insurance or those subject to a deductible, copay, or coinsurance copay be eligible under the HSA? Further it they are eligible, can the FSA be used along with the HSA to cover these expenses? Thank you.

First off, if you have an HSA you may already know the FSA must be limited purpose (LPFSA)-for dental and vision expenses only. The answer to your expense question is industry standard...that is you can use your HSA to pay for dental expense so long its medically necessary and covered in Pub 502 of the IRS code (generally ok so long as its not cosmetic). If you have the LPFSA, you should use that first for dental expense and then you can use your HSA once the LPFSA is exhausted. Hope that helps.