Can my choice of co-authors affect how often my article is cited? I am a post-graduate student in dentistry; planning to publish an article either in an Indian journal or an international one. How does having co-authors like our seniors or our professors affect number of citations for my published article?
First of all, let me make it clear that I'm addressing your question with the hope that you tacitly mean co-authors who made significant enough contributions to deserve authorship, and not talking about gifting co-authorship to people who haven't. Ethically, the latter is wrong, even when the person in question is the PhD supervisor, and hasn't contributed enough to deserve authorship. Thus, what I'm referring to below is the issue of publishing with or without co-authors who deserve to be co-authors.

In an ideal world, what should matter is only whether the content of article is scientifically sound, and not the brand value of the authors. What is wrong does not become right when stated by a bigshot. But in parallel, there is a question of credibility, and that is generally higher for people who are known to have done some good work in the past, as opposed to a newbie. But even with that, it is not that people do not read the works of newbies, just that in the real world, people are less likely to be as critical of a bigshot, as they would be of a newbie. That's just to say that we do not live in an ideal world. However, if the science in the newbie's work is accurate, it will fetch respect too. That's how eventually everyone grows in stature.    

However, we should distinguish between exposure and citations. Even with my arguments above, being on the same wagon as a bigshot may ensure more exposure (i.e. more people look at it, even though it may not go any further than that), citations are not really entailed by a greater exposure, but are more reflective of the utility of the article. Thus, a useful work is going to get cited irrespective of who is on the author list, and exposure only increases the odds of the same.