I wonder about your working style. From your problem, I would like to suggest following approach.
1) It seems that you don't have any coding standards in place, please prepare them and approve them from Top management.
2) Always ask programmers to create a 'Design report', before he/she touches the code, carry out the practice of 'Design review' by some unbiased 'Senior' programmer (Not you, since you already have conflict with the said guy)
3) Always remember that OOP is Not always right approach and hence in case of any conflict, call up a meeting with Senior Programmers and both of you, and come to some conclusion at the end of the meeting.
4) DO NOT Force programmer to write code if he is Not okay with your design, simply because he would Not give you good output. In that case change the programmer.