here comes the coolest dental student ever..... k, maybe not.
ben, here's the clarification. You got a lot of them right, actually.
The gel thing is topical anesthesia. Since the most painful part, according to the oral surgeon taught us injections, is when penetrating the mucosa layer, it'll help with the pain. (I just think it hurts all the way no matter what)
And, yes, the drilling part is to get rid of the bacteria soaked/infected enamel (the "calcium" part) and dentin, and shape the hole in your tooth so that the filling material put in there won't fall out that easily.
The syringe with blue gel is actually weak phosphoric acid. The "toothpick" thing is a bonding agent delivered by an applicator. When she appeared to "squeeze" out stuff, she's squeezing out of composite filling material, in a clay-like stage, to fill in the hole she digs out. The last thing's the "rod," a curing light, that hardens the filling material. This is how it works:
Our dentin actually has little hollow tube's in there, and when you drill a tooth, the debris will clog the holes. The phosphoric acid is meant to remove that layer. Also, it will create uneven surfaces on your enamel and dentin. Why? It is to maximize the surface area the filling material can bond to both chemically and mechanically. The bonding agent will bond to tooth structure chemically/mechanically, bond to the filling chemically and provide the most "retention" of the filling (while the old silver filling only relies on mechanical retention from its shape). The composite filling is a polymer of lotta different things in different phases. Long story short, you put in the thing, adopt it to the hole and tooth's anatomy and shine it with a light. The light will polymerize the composite and the thing hardens. This is your good old light-> free radical -> breaking double bonds -> cross linking reactions.
And to shape the filling? This is when we get artistic/obsessive compulsive and carve out the anatomy to restore your original tooth shape with various shaping instruments. Different part of the tooth has its own function... like, preventing food from getting in between your tooth, biting, looking pretty, etc. We have to restore them to the most ideal shape. And, most importantly, we'll have to make sure there's no cut tooth structure exposing nor excess filling material sticking out (if it's at the gum level, it will cause inflammation).
you are actually the FIRST person to ask me how things work, and it's nice to have people taking interests than saying "stop hurting me"... hahaha....
