Class IV Restorations and a Diastema Closure

5 minute read
Woman with a Diastema

Previously, I wrote about my experience learning how to perform class I, III, and V restorations with both composite and amalgam. This week we added some new tricks to our repertoire with class IV restorations and a diastema closure.

I am switching from using my phone for imaging to the USB intraoral cameras they provide in the SIM clinic. The image quality may be a tad worse, but the lighting will be much better. I know my work is far from perfect, but hopefully it will give you an idea of what we are doing in our third of week of our second year!

My first diastema closure

A diastema closure is pretty daunting when you only just learned how to do a class IV restoration a few days ago. Getting the symmetry just right, nailing the emergence profile, and ensuring that you have proper aesthetics are all big challenges. As with anything else that is difficult, your best bet is to break it into smaller more manageable steps.

Step 1 – Fake teeth go into the fake mouth

Just getting the pre-prepped teeth into your typodont can be a bit of a challenge… Just look at the gaps on the distal edges of #8 and #9!

Lingual view of a typodont diastema

I know what you’re thinking—what happened to that gingiva? It looks like Freddy Krueger took a spin around that periodontium. And at this point, with my hand skills, you’re really not far off.

Freddy Krueger

To be fair though, those mangled gums are the product of a project I did during my first year. Trust me, you definitely don’t want a first year dental student working anywhere near your gums!

Facial view of a typodont diastema

Step 2 – Size things up

In case you are wondering, the black lines are to mark where I placed the digital calipers. I didn’t take a picture of the measurement, so just trust me that the distance from the distal of #8 to the distal or #9 was exactly 16.0 mm. Divide that in half, and our goal is to make each tooth exactly 8.0mm wide. Easy! (Not)

Step 3 – Gluma first, then the acid

Our plastic teeth were already prepped for us, so all we had to was place Gluma, bevel the margins, etch, prime, and then bond. I went with a modified long bevel (starburst bevel) because it offers better aesthetics. Not that it matters when you aren’t color-matching.

Step 4 – Feminize that tooth

I used mylar strips to get the emergence profile, line angles, and the margins just right. The goal is to make the tooth round, not boxy. Or, as Dr. Foley puts it, we want to “feminize” the tooth. I like my teeth to have curves.

Using a mylar strip, a wedge, some crafty finger placement, and a few four-letter words, you will eventually get the shape you are after. Start at the gingival margin, then build out a lingual scaffold. Apply composite to the facial and shape it all with your mylar.

If you are good with mylar you can avoid doing much finishing or polishing at all. I am not good with mylar, so I had to do a lot of finishing and polishing. I got better each time though, so here’s hoping!

Step 5 – Finish and polish

This is the part I enjoy most. I used finishing discs to contour the facial, a 7404 carbide football bur for the lingual surface, and a 7901 flame bur to tackle some of the tight interproximal spots. For the embrasures I mostly used a 12-blade scalpel and sanding strips. For the polish I used an Optrapol and a polishing brush (more on that later).

Diastema closure success

Perfect? Obviously not. But not bad for my first diastema closure! I wish the gingiva hadn’t already been so mangled though. You may have noticed a smear of composite on the facial of #8. This is what happens when your polishing brush is spinning too fast and you catch an edge… No water + hot brush = melted tooth surface. As you can see from the picture, I went ahead and filled it.

My first class IV restorations

We have now learned four of six types of restorations. Since class six restorations are pretty straightforward, we really only have one more to learn and that is class II. Class IV restorations are notoriously difficult with plastic teeth. I am pretty satisfied with my first attempts on #7 and #8.

Gum damage from D1 year again. 😳

You can see my class V preps on #29 and #30 too. Actually, the prep on #30 looks huge in this image! Those class Vs were our final project of D1 year. You can see that I am getting better about not hitting gum tissue during my restorations.

Tomorrow morning we will take our first practical exam as D2 students. We don’t know what they will ask, so naturally we are all a bit nervous. Anything we have learned up to this point is fair game. Until next time!


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