there are 2 approaches to it.if you have time on your side you can opt for long term treatment.if you need quick results you have to go in for quick results treatment.for quick results,i am not aware of the extent of the gap but if its not too high then a filling can be done using a material called composite which looks the same colour as your natural tooth.the problem with that is it can chip or discolour over a period of time.you can also go in for ceramic veneers that are thin chip like prosthesis put on the front teeth.they are very good looking and will do the job but are slightly expensive and also invasive as they have to minimally grind away the tooth surface.you can also consult the orthodontist for a long term solution for your problem as the orthodontic treatment may take over a year but is the least invasive.
Next Steps
consult an esthetic dentist or a prosthodontist for quick results and orthodontist for long term results
Health Tips
opt for the least invasive options first