Cutting the Cavities . . .
Thursday, July 21, 2005
During the first quarter, Thursdays are operative days. That means we have an hour lecture in the morning, and then we spend 3 hours in the lab. We take a lunch, and come back for an hour long afternoon lecture, and then we spend anohter 3 hour in the lab.
This morning, the carpool got to school around 6:15am. The doors were still locked and our badges don't open the doors until 6:30am. Today, a faculty member saw us waiting and let us in a few minutes early. Class didn't start until 8am, so I used the time to try and pour up some more molds. It took me another 4 attempts on the mandibular arch until I was able to get a good vestibular fold all around the tray. Unfortunately, I used a terrible vibrator so the stone didn't flow into all the mold, and I ended up missing a few teeth. Frustrating. It was time for class, so I abandoned it until lunch.
Our operative lecture covered the GV Black's steps for preping a tooth for restoration. Then we narrowed it down to preparing the tooth for an amalgam restoration on the occlusal (biting) surface of a second molar. Essentially, you cut a trench that is 1.5mm following the cental groove and around the cusps by partially going up the supplemental grooves that separate the cusps. There are a few other little details like keeping the walls parallel to the long axis of the crown, sloping the pulpal foor from buccal to lingual, and flaring the mesial and distal dovetails. When you are all finished, you have a prep that looks like a dog bone. I'll take a picture of it tomorrow and post it.
The tooth we cut was number 31--that is the second molar on right side of the mandibular (lower) arch. Since it was our first prep on a typodont tooth, we cut it on the bench top. We made our inital cut with a #330. Then we trimmed it up with a #56. It took me about an 2 hours to cut it all down to size. The row instructor thought it was really good for my first try. Then she reminded me that eventually, that same prep would only take me 2 minutes to cut.
I ate a fast lunch, then I ran back upstairs to the simlab to take another impression. I nailed it the first time. It was the best one yet. The trick is making sure to get the alginate goop that squirts out the back with your finger and the then spreading around the vestibule before it gels. Also make sure to press down hard enough (but not too hard) on the incisor portion of the tray to get a good clean impression of the anterior teeth and vestibule. I had the whole thing poured and mounted by the end of lunch--I'm getting faster.
After lunch, we had a lecture on how to cut the first molar on the left side of the mandibular arch (#19). This tooth was a little different because it had 5 cusps instead of 4 like #31. We also learned about proper chair position and patient height for working on the mandibular teeth. We were in the lab by 2pm, and this time we cut the teeth in the dummies mouth. I have affectionately named my dummy, Buddy. Each student has to name their dummy and treat them like a real patient with charts, etc.
Cutting teeth in the mouth took about 20 to 30 minutes to get used to. I had gotten accustomed to using the bench top. After a few minutes, I actually preferred the dummies mouth. Some students didn't make the transition as smoothly, but I'd estimate that 50% of the class adjusted as easily as I did.
During the next 3 hours I cut a prep on another #30 and I did one more #19. We have 2 weeks to come up with the best possible prep we can muster for each of those teeth. I'll probably carve at least 10 more of each. I found a couple more burs that I like to use in addition to the #330 and #56. For those of you in dental school, you'll recognize these. I liked the #56 diamond, the #57, and the #957. All good burs for getting the prep done quickly and cleanly.
I've got a load of anatomy to do tonight. So, I'm off.
During the first quarter, Thursdays are operative days. That means we have an hour lecture in the morning, and then we spend 3 hours in the lab. We take a lunch, and come back for an hour long afternoon lecture, and then we spend anohter 3 hour in the lab.
This morning, the carpool got to school around 6:15am. The doors were still locked and our badges don't open the doors until 6:30am. Today, a faculty member saw us waiting and let us in a few minutes early. Class didn't start until 8am, so I used the time to try and pour up some more molds. It took me another 4 attempts on the mandibular arch until I was able to get a good vestibular fold all around the tray. Unfortunately, I used a terrible vibrator so the stone didn't flow into all the mold, and I ended up missing a few teeth. Frustrating. It was time for class, so I abandoned it until lunch.
Our operative lecture covered the GV Black's steps for preping a tooth for restoration. Then we narrowed it down to preparing the tooth for an amalgam restoration on the occlusal (biting) surface of a second molar. Essentially, you cut a trench that is 1.5mm following the cental groove and around the cusps by partially going up the supplemental grooves that separate the cusps. There are a few other little details like keeping the walls parallel to the long axis of the crown, sloping the pulpal foor from buccal to lingual, and flaring the mesial and distal dovetails. When you are all finished, you have a prep that looks like a dog bone. I'll take a picture of it tomorrow and post it.
The tooth we cut was number 31--that is the second molar on right side of the mandibular (lower) arch. Since it was our first prep on a typodont tooth, we cut it on the bench top. We made our inital cut with a #330. Then we trimmed it up with a #56. It took me about an 2 hours to cut it all down to size. The row instructor thought it was really good for my first try. Then she reminded me that eventually, that same prep would only take me 2 minutes to cut.
I ate a fast lunch, then I ran back upstairs to the simlab to take another impression. I nailed it the first time. It was the best one yet. The trick is making sure to get the alginate goop that squirts out the back with your finger and the then spreading around the vestibule before it gels. Also make sure to press down hard enough (but not too hard) on the incisor portion of the tray to get a good clean impression of the anterior teeth and vestibule. I had the whole thing poured and mounted by the end of lunch--I'm getting faster.
After lunch, we had a lecture on how to cut the first molar on the left side of the mandibular arch (#19). This tooth was a little different because it had 5 cusps instead of 4 like #31. We also learned about proper chair position and patient height for working on the mandibular teeth. We were in the lab by 2pm, and this time we cut the teeth in the dummies mouth. I have affectionately named my dummy, Buddy. Each student has to name their dummy and treat them like a real patient with charts, etc.
Cutting teeth in the mouth took about 20 to 30 minutes to get used to. I had gotten accustomed to using the bench top. After a few minutes, I actually preferred the dummies mouth. Some students didn't make the transition as smoothly, but I'd estimate that 50% of the class adjusted as easily as I did.
During the next 3 hours I cut a prep on another #30 and I did one more #19. We have 2 weeks to come up with the best possible prep we can muster for each of those teeth. I'll probably carve at least 10 more of each. I found a couple more burs that I like to use in addition to the #330 and #56. For those of you in dental school, you'll recognize these. I liked the #56 diamond, the #57, and the #957. All good burs for getting the prep done quickly and cleanly.
I've got a load of anatomy to do tonight. So, I'm off.
posted by Cyrus and Annie at
8:04 PM
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