If you dont feel entirely comfortable doing something, then surely it is worth discussing this with your employer.
I am not sure what is it that you are uncomfortable with? From the way you have worded your question, it appears it is because you are both male. This shouldn't pose any significant harm, as two dental professionals working to provide good quality care for those who need it. Are you concerned that your visits might be misinterpreted? Perhaps this is simply your own worries manifesting themselves. Would two women doing the same thing cause you to feel uncomfortable?
I wouldnt think anything of it, Male or female.
Domicillary visits are for providing those who are unable to access dental care by usual means and is a way of reducing the barriers to care in the community. That is all.
Have a think about why things feel so wrong for you and address those issues firstly.
All the best : )