Creating new variable?

I think what I need to do is create/compute a new variable, but I'm not sure.

I'm looking at incidence of cavities in teeth. The way I collected the data is by individual tooth were 0 = no cavities, 1 = one cavity, 2 = one or more cavity in the tooth. But now I want to look at the incidence of cavities in the upper vs the lower jaw. Combine the data from all of the upper teeth to get a simple frequency/percent of cavities in the upper jaw.

It seems like it should be easy, but I'm having problems figuring it out.

Any suggestions would be great! Thanks.


TS Contributor
What is the data structure like? Is it

Subject1 - Cavities in tooth 1 - Cavities in tooth 2 - ...
Subject2 - Cavities in tooth 1 - Cavities in tooth 2 - ...

or is it

Subject1 - Tooth1 - Cavities
Subject1 - Tooth2 - Cavities
Subject2 - Tooth1 - Cavities
Subject2 - Tooth2 - Cavities

Kind regards