Hi there, I'm a 4th year UCLA dental student. Clinical experience doesn't start the 1st year. You are placed in a vertical tier team (usually consisting of a 4th yr, 3rd yr & 2nd yr) when you become a 2nd yr, and that is when you can start going into clinic. Starting the fall quarter of 2nd yr, you are cleared to do operative (such as fillings) & cleanings. And you are cleared to do fixed prosthodontics (such as crowns) the winter quarter of 2nd yr. However, 2nd yr is intense academically & you have a lot of lab classes, so people usually don't do much in clinic their 2nd yr. Plus, you don't have your own patients as a 2nd yr. So you are relying on your 3rd & 4th yrs to provide you with things to do. (For example, I did perhaps 2 operative, 5 simple cleanings, & 1 crown total the whole 2nd yr). We have what's called 2nd yr 4th yr operative & crown in which your 4th yr will assist you in doing your very first operative & crown during the 2nd yr. You really don't start going to clinic alot until 3rd yr. By then, you'll have your own patients to take care of.
You can get clinical experience earlier by doing extracurricular clinical activities, such as attending health fairs (you can give oral hygiene instructions, place sealants) & attending Venice clinic or USC/UCLA mobile clinic.
There is no such thing as a mobile clinic rotation at UCLA. The mobile clinic is extracurricular activity.