Environmental changes in temperature and humidity can cause wood to expand and contract. Cabinet doors are constructed with a small tolerance in the frame groove, which allows the panel to move slightly within the frame to allow for expansion without causing damage to the frame. The natural process of expansion can create open joints in the finish. An open joint line related to expansion or contraction is not considered a defect. The finish will still protect the surface, and this does not affect the structural integrity of your cabinets. Some joined wood may have highly visible joint lines while others may not show any. Joint lines may also occur due to repeated impacts from everyday use. An exposed open wood joint can be damaged from prolonged exposure to water or significant moisture. It is important to wipe off any moisture from cabinet surfaces as soon as possible.