South Shore Dental Group has renewed its 5,123 s/f lease at Plaza Executive Center, 300 Granite St. Richard McKinnon, director of brokerage service at The Grossman Cos., Inc., represented South Shore Dental, while J. P. Plunkett of Cushman & Wakefield represented the property owner, Sun Life Assurance Company of Canada. South Shore Dental Group offers cosmetic, restorative and specialty services.