Why did I get an infection..root canal treatment

[mermaid216]

My question is a very simple one, but I will explain..
I had a root canal done recently on my right central incisor after having a horrible throbbing pain for around 5 days. I went to the dentist and was told I would need a root canal as i had an infection. I am just very curious as to why this has happened to me. To give some background, I am good with my oral hygiene, brushing twice a day and flossing occasionally, and I have never had a cavity in my life.
Because of this, I am wondering if the infection has come from an early trauma I had when I was around 7/8 years old (bearing in mind I am 18 now, so 10 years on) when I was playing outside and fell off a wall and chipped the corner off my right central incisor. then having to get it fixed. I am not sure of the procedure that was done to my tooth, being that I was so young.
Is my root canal treatment all these years later a direct result of this trauma I suffered as a child? Or is it just something that has simply happened?

[scottma]

Trauma may cause dental pulp necrosis without clinical symptom for years.as long as there is no fracture, tooth can be rescued.

[mermaid216]

I see. Thank you!