According to the report, colour is important, and too many are now bleached too white. Dr Davis said： "The teeth should be the same colour as the whites of your eyes. If the teeth are too white, they become more dominant than the eyes."There are strict mathematical ratios governing the ideal smile, says Dr Davis. Its width should be no less than half the of the face at the same height and, for the best effect, both upper and lower lips need to be symmetrical each side of the mid-line of the face.

　　根据报告，颜色是很重要的，但现在不少人为拥有明眸皓齿不惜过渡漂白。戴维斯博士说：“牙齿与双眼最好一样白。如果牙齿太白，就会喧宾夺主。”戴维斯博士还表示，完美笑容有严格的数字比例。张开的嘴宽度不能小过半边脸的宽度，上唇与下唇两边嘴角要对称，如此才能交出最完美的笑容。