The Chairside Instructor 32 Fixed Bridge Placement Tooth Replacement Missing tooth To replace a missing tooth with a conventional three-unit bridge, teeth next to the gap are reduced. The custom-made bridge is placed over the prepared teeth. After adjustments are made, the bridge is cemented into place. Using a floss threader, insert floss under the bridge. Gently rub the side of each tooth next to the bridge with the floss, cleaning under the gum too. Flossing Under a Bridge Rub the floss from side to side along the underside of the pontic. Pontic