Freddie Mercury knew that there was treatment for his alignment issue, and he certainly could have afforded to fix his bite. However, he refused to undergo any treatment for his condition.
Though his teeth caused him embarrassment, Mercury believed that his unorthodox bite and teeth were responsible for his incredible range and he did not want to change them in case his voice was negatively affected. Instead, he often covered his mouth with his hand and even grew a mustache to draw attention away from his teeth.