The factors that mainly influence smile design are

• Your facial shape. For example, a long face may need to accentuate width to appear more oval. Someone with attractive features in the center of the face may need bold central incisors to draw attention to that center
• Your image aspirations. How do you want to appear to others? A sophisticated smile gives the appearance of more intelligence, maturity and judgment. A sexy smile gives the appearance of more warmth, energy and boldness
• Your age, or how old you want to appear. Longer central incisors make you appear younger. Also, whiter teeth make you appear younger. Conversely, a flatter smile or a more subdued color to the teeth make you appear more mature

Along with the teeth, the gums, technically known as the gingiva also play a significant role. There is certain proportion of pink to white, which has to be maintained for the smile to be pleasing and beautiful. At times, the only difference between an excellent smile and a run of the mill smile can be heavily pigmented gums. If there is discrepancy in any of the above listed factors, the smile tends to get unaesthetic. It is not that if any one of the above conditions is not met, the looks will be totally hampered. Many a time, totally out of position teeth or disproportionate teeth may still exhibit a very pleasing smile. When the smile does get unaesthetic, the dentist can play a large role in correcting these discrepancies.