If you have crooked teeth, or teeth with unwanted gaps, but you want to show off a dazzling smile in a photo, have no fear. While you could spend thousands of dollars on orthodontics, another simple and inexpensive option is to straighten your teeth in Photoshop.
Scan your photograph at high resolution to get as much detail as you can. Try enlarging the image by 300 to 400 percent (you can also increase the pixels per inch to 200 or 300).
Open your digital image file and zoom in on your teeth by choosing "Zoom In" from the Edit drop down menu. Close any gaps between teeth before you straighten. Choose the "Magnetic Lasso Tool" and drag the cursor around the edge of the teeth and gums to the left of the gap so that the selection area snaps to the outline of the bridge. If the tool selects more than you want use the tool options to set the tolerance lower.
Hold down the "Command/Control" and "J" keys to copy the selection to a new layer (you can use the layers palette to and name the new layer "Left Bridge"). Select the bridge to the right of the gap and copy it to a new layer (name it "Right Bridge").
Select the left bridge layer and hold down the "Command/Control" and "T" keys to load the Free Transform tool. Carefully drag the center right bounding box handle to stretch the selection about halfway toward the other bridge. Close the remaining gap by using Free Transform with the right bridge layer. The will appear perfectly aligned and the gap will disappear.
Select and correct crooked teeth one at a time. After you select each tooth, hold down "Command/Control" and "T" keys to load the Free Transform tool. Hold the cursor at one of the corners until you see a curved arrow and rotate the tooth until it is straight then use the arrow keys to adjust the position. You may need to stretch the tooth from one side or the other to close any gaps.
Choose the "Erase to Background" tool from the toolbar. Paint the edges of the left and right bridge layers to remove any stray pixels that might mar the new look. Select both bridge layers and choose "Merge Down" from the layers menu options palette.
Save your file. Use the "Save for Web" command to create a JPEG version to email to your new friend.