The gap between teeth after scaling increases due to compression by calculus, resorption of the alveolar bone, and loosening and shifting of the teeth after gum recession, thus creating a gap. If it is gingivitis then the gap will gradually recover because there is no compression. If the periodontitis is well controlled and the gap is small, resin can be used to fill the neighboring surfaces or make inlays or full crowns to close the gap, avoiding the formation of overhanging protrusions and reducing the retention of plaque. If the gap is large, orthodontic traction can be performed to realign the teeth and reduce the gap after movement. If horizontal resorption of the alveolar bone causes the formation of a black triangle gap, periodontal flap surgery is needed to place bone powder and periosteum to restore the height of the alveolar ridge and to close the gap after formation of a new periodontal attachment so that the black triangle disappears.