My wife has a Mexico dentistry degree she has been working 2 years as dental assistant and employer says they can sponsor a visa, which one can apply?

The TN professional list and H-1B specialty occupation both contemplate dentists, not dental assistants. Besides, even if your wife did qualify as a dentist for H-1B sponsorship, she would need a cap H-1B, and those are regulated by number. Employers and their candidates have to go through a selection process in order to even be able to submit petitions, and the time for selection this year just ended on March 17, 2023. It may be possible for the practice to sponsor her for a PERM labor certification and green card, which does not need any of the above – but in which the employer will have to go through a time of recruitment of US workers to show that your wife is not taking away a job that an able, willing, qualified and available US worker wants.  Please note that applying for PERM does not allow her to stay in the US during most of the process and she will have to keep maintaining a legal non-immigrant status. Due to the limitations of the Lawyers.com Forums, Alan Lee & Arthur Lee, Esqs.’ (the "Firm") participation in responding to questions posted herein does not constitute legal advice, nor legal representation of the person or entity posting a question. No Attorney/Client relationship is or shall be construed to be created hereby. The information provided herein by the Firm is general, and requires that the poster obtain specific legal advice from an attorney. The poster shall not rely upon the information provided herein as legal advice nor as the basis for making any decisions of legal consequence.