A cheek retraction device (100, 200) comprising a frame (102, 202) having anterior and posterior portions for insertion into an oral cavity, which is selectively collapsible and expandable so as to be in a collapsed configuration to facilitate insertion into the oral cavity and an expanded configuration while positioned in the oral cavity in order to bear against and retract soft oral tissue so as to isolate one or more teeth from soft oral tissue and create an enlarged working field, the frame comprising: an upper frame element (104, 204) configured to bear against and retract cheeks and upper lip away from teeth of an upper dental arch when said frame is in said expanded configuration in an oral cavity; a lower frame element (106, 206) configured to bear against and retract cheeks and lower lip away from teeth of a lower dental arch when said frame is in said expanded configuration in an oral cavity; and wherein: the upper and lower frame elements (104, 204; 106 206) each comprise left and right frame portions (108, 110; 112, 114; 208, 210; 212, 214) at the opposed posterior portions of the frame, the frame further comprising a posterior frame element (124, 224) extending between opposed left and right frame portions, wherein said upper and lower left frame portions (108, 112; 208, 212) are joined to one another to form an acute angle between them on one of the opposed posterior portions of said frame, said upper and lower right frame portions (110, 114, 210, 214) are joined to one another to form an acute angle between them on the other of the opposed posterior portions of said frame, the upper and lower frame elements (108, 110, 208, 210; 112, 114, 212, 214) are flexible so as to permit the upper and lower frame elements to be at least partially folded toward each other, and a posterior width (120, 220) of the upper and lower frame elements as defined between the right and left frame portions in the posterior portions of the frame is greater than an anterior width (122, 222) of the upper and lower frame elements in the anterior portions of the frame. an upper frame element (104, 204) configured to bear against and retract cheeks and upper lip away from teeth of an upper dental arch when said frame is in said expanded configuration in an oral cavity; a lower frame element (106, 206) configured to bear against and retract cheeks and lower lip away from teeth of a lower dental arch when said frame is in said expanded configuration in an oral cavity; and wherein: the upper and lower frame elements (104, 204; 106 206) each comprise left and right frame portions (108, 110; 112, 114; 208, 210; 212, 214) at the opposed posterior portions of the frame, the frame further comprising a posterior frame element (124, 224) extending between opposed left and right frame portions, wherein said upper and lower left frame portions (108, 112; 208, 212) are joined to one another to form an acute angle between them on one of the opposed posterior portions of said frame, said upper and lower right frame portions (110, 114, 210, 214) are joined to one another to form an acute angle between them on the other of the opposed posterior portions of said frame, the upper and lower frame elements (108, 110, 208, 210; 112, 114, 212, 214) are flexible so as to permit the upper and lower frame elements to be at least partially folded toward each other, and a posterior width (120, 220) of the upper and lower frame elements as defined between the right and left frame portions in the posterior portions of the frame is greater than an anterior width (122, 222) of the upper and lower frame elements in the anterior portions of the frame. the upper and lower frame elements (104, 204; 106 206) each comprise left and right frame portions (108, 110; 112, 114; 208, 210; 212, 214) at the opposed posterior portions of the frame, the frame further comprising a posterior frame element (124, 224) extending between opposed left and right frame portions, wherein said upper and lower left frame portions (108, 112; 208, 212) are joined to one another to form an acute angle between them on one of the opposed posterior portions of said frame, said upper and lower right frame portions (110, 114, 210, 214) are joined to one another to form an acute angle between them on the other of the opposed posterior portions of said frame, the upper and lower frame elements (108, 110, 208, 210; 112, 114, 212, 214) are flexible so as to permit the upper and lower frame elements to be at least partially folded toward each other, and a posterior width (120, 220) of the upper and lower frame elements as defined between the right and left frame portions in the posterior portions of the frame is greater than an anterior width (122, 222) of the upper and lower frame elements in the anterior portions of the frame.