Mystic — The Stonington Planning and Zoning Commission on Tuesday unanimously approved a controversial proposal to build a three-story, 10,550-square-foot medical/office building at the corner of Masons Island Road and Harry Austin Drive.

Some residents opposed the plan by Summit Street Development during a public hearing on Tuesday night, but the commission approved a change from a dental clinic to medical and office use, additional parking, expansion of gross floor area ratio and changes to the layout of a previously approved building and the site.

In 2013, neighbors opposed plans for a dental clinic on the one-acre property, citing negative impacts of the project on traffic and the character of the neighborhood. The commission rejected the application but Summit Street appealed, and a judge overturned the commission’s denial, which gave Summit Street the right to proceed with the dental clinic project.

The newly approved building is 1,260 square feet larger than the originally proposed dental clinic.