Dentists and researchers have come up with the formula for the perfect smile, from the size and width of each tooth to the curve, colour and shape of the teeth, and the overall width of the smile.

    Those pursuing perfection are advised to hide their gums, hold back on the bleach, cover the bottom teeth and set their lips at just the right angle."Everyone wants the perfect smile and Jessica Simpson is the one we get asked to reproduce the most," says Dr Nicholas Davis of Loma Linda University School of Dentistry.

    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.

    牙醫和研究學者已經研究出完美笑容秘訣，從每顆牙齒的大小、寬度到牙齒的曲線、顏色和形狀以及張開的嘴寬度都有講究。 
 
    專家建議，那些追求完美笑容的人應該藏起他們的牙肉，不要漂白牙齒，不要露出下排牙齒、嘴唇要保持合適的弧度。洛馬·林達大學牙醫學院的尼古拉斯·戴維斯博士說：“每個人都想擁有完美笑容，而杰西卡·辛普森成為最多人模仿的對象。”

    根據報告，顏色是很重要的，但現在不少人為擁有明眸皓齒不惜過渡漂白。戴維斯博士說：“牙齒與雙眼最好一樣白。如果牙齒太白，就會喧賓奪主。”戴維斯博士還表示，完美笑容有嚴格的數字比例。張開的嘴寬度不能小過半邊臉的寬度，上唇與下唇兩邊嘴角要對稱，如此才能交出最完美的笑容。