All the general dentists will do tooth filling no need of any specialist , if you need specialist only to treat you then you have to approach Endodontist , Also before filling first we need to examine up to what extent the the decay has progressed , if the decay is deep then filling cannot be done and Root canal treatment should be done

Hello Depending upon the distance of the gap the treatment can be planned. Visit for a consultation and they would guide you through. If the gap closure is via braces/ aligners you need to visit an orthodontist. If the closure is via fillings and crowns you need to meet an endodontist / cosmetic dentist.