Gaps in the esthetic zone are fairly common, they are the results of different reasons, like having small size teeth, large frenum of the upper lip, permanently missing lateral incisors, and others. Some people don’t mind having them, but some like them closed.
They can be restored orthodontically by moving teeth and closing the gap, using bonding material or porcelain veneers/ crowns.
In general, the specific situation of each individual would dictate different approach for ideal results, since trying to close a large gap restoratively by adding composites, or by fabricating a veneer or crown, would result in changing the proportions of the tooth ( height to width) and would create a teeth that looks square in shape.
I consider a gap of 1-2 mm is an ideal situation to close. Anything over 2 mm, would greatly affect the Golden Proportions of height to width. And even though it is possible, but it is not recommended.
Here is a case of a 2 mm gap that I just closed, with favorable results.
From your Dentist in Laurel MD