Murder by Decay — Suzanne Young

Edna Davies is distressed. She is suffering from the worst toothache she can remember, and her dentist can't help her. He is the prime suspect in a homicide, and his office has been sealed off as the crime scene. His guilt would mean he purposely led Edna into a trap, an act of betrayal she will not accept. As she attempts to learn the truth, she stumbles into a web of intrigue dating back ten years. With the help of a little stray terrier, she finds her answers, but nearly loses her life in the process.