Hi Karen. A tooth is narrower towards the root and flares out towards the incisal surface often in a triangular shape. When gum receeds, the interproximal surfaces of the teeth are exposed and triangular gaps appear. Two thoughts. Firstly- Periodontists are able to graft tissue in the areas of gum recession and you should ask your periodontist about this. Secondly- Veneers cover the front surfaces of teeth and they can be shaped in such a way to extend outwards to close up the triangular gaps. The tooth shape may not appear as triangular, but will take on a more oval shape. The teeth have to be prepared in a way to allow the veneers to partially wrap around them. Please send me an email if you need more information. Sincere regards Michael.