Should I take the cord out?


I often help students at NYU College of Dentistry with their crown and bridge impressions. They usually are interested in my opinions about cord. "Do you use a double cord technique?" "Do you take out one or both cords before taking an impression?". It seems that some  students are unclear about how to properly use cord to help take a final impression and I believe this post should be of help.

My answer about whether to use a double or single cord technique usually doesn't completely satisfy, since I am not particularly dogmatic. I explain that the sole purposes of retraction cord is to retract and to help stop bleeding by applying a slight pressure on the capillaries. I pack enough cord that the gum is slightly retracted. I usually place a small cord first, either 00 or 0. If my entire margin is then visible, I don't need a second slightly larger cord. If I can take an impression with the cord in, I do. If I can't,  I take it out. If there is any bleeding, I will reapply Viscostat gently and then rinse  with water without air spray. If there is even a little bleeding I repeat the application and rinse again. I do this repeatedly until I am able to dry the tooth with air , see the entire margin (without tissue tags contacting the finish line) and have no bleeding. At this point I am ready to take our impression.

Double cord technique is best employed when at least part of the finish line is subgingival, since more retraction is needed. The two cords are packed one on top of the other with the smaller cord packed first. Cord is always wet first with Viscostat ( I never pack dry). The larger cord just has to put pressure on the first cord so that it is pushed more subgingivally. The larger cord doesn't have to be fully packed under the gum, but must put some direct pressure on the smaller cord. Once packed, I place a wet two by two over the prep with the packed cord, have the patient bite down and wait four minutes.

During the wait I have the student set up their impression materials and paint the impression tray with an appropriate adhesive ( NO Alginate Adhesive PLEASE!) . At the end of the four minutes I ask the patient to open their mouths and usually I place a bite block on the contralateral side. I usuallly place cotton rolls on either side of the teeth that are to be impressioned. At this point I wash the preps and make sure all the coagulum debris is off the prep(s). I leave the cord wet with water afterwards and gently tease out the cord. If there is bleeding, I will reapply Viscostat until the bleeding stops . If the smaller first cord is not covering the margin of the prep, I carefully dry the prep and take my impression. If the margin is not fully visible, I rewet the remaining cord with water and remove it. after it is removed I gently wash the prep and then dry using the air syringe. If there isn't any bleeding I take the impression. If there is bleeding I reapply  Vryiscostat. until the bleeding stops.

That is my basic technique. If I miss my impression because of moisture contamination, or the student moved the tray while it was setting or because there is a void. I often repack my cords, making sure to re- wet them with Viscostat first. Since I do not own a laser or even an electrosurgery unit, I do not employ them to facilitate the taking of final impressions. One way or the other I am able to get a clear impression (sometimes it take me multiple try before succeeding) If  I have left something out or if readers have any questions they should feel free to email me at lawrencespindel@yahoo.com.




from Ask Dr. Spindel - http://lspindelnycdds.blogspot.com/2019/09/should-i-take-cord-out.html - http://lspindelnycdds.blogspot.com/

Comments

Post a Comment

Popular posts from this blog

Help! My Child is Terrified of the Dentist

Image
If you’re the parent of a young child, you know their brains are similar to sponges that soak up everything around them—especially in their first five years, which neuroscientists say is when they’ll do the most learning and developing in their entire life. At this formative time, your child may amaze you with what they notice: your facial expressions, the different tones of your voice, and your habits. If your habits include regular dental visits and an excellent oral hygiene routine, they’ll notice and want to emulate you. If you happen to feel anxious about your dental visits, or you groan when you’ve got to floss and brush, they may synchronize and feel your dread. This could lead to dental fears that stick with them for years—potentially a lifetime! Kids Can Be Courageous If you’re feeling guilty right now, go ahead and put that away as it won’t serve you or your little one. Everyone has some room for improvement, and Coastal Pediatric Dentistry® is here to help show you an...
Read more

Going for the Gold?

Image
On the left is the older allow, on the right the new one that my lab has chosen to use The cost of a penny weight of pure gold is currently $79.53. The cost of a penny weight of pure palladium is $130.6. It used to be that palladium was added instead of gold to the precious metals often used for pfms, but now laboratories are finding that palladium is no longer affordable. The lab that I am using has just changed the formulation of the metal it's using to one that has more gold than palladium. I really do not mind, but metals with more gold are softer and often easier for a dentist to accidentally polish off delicate margins. It is important when polishing "higher gold" formulations to exert less hand pressure when performing the final polishing of the crown's margins. Other wise there should be no problem with this change. Traditionally labs have chosen alloys with higher gold percentages for optimal esthetics, since alloys with higher concentrations of ...
Read more

Lemon Juice – The Good, the Bad, & the Sour

Image
In a great tale of opposites, lemon juice can be both acidic and basic, or alkaline. Read on to find out why people are talking about this, and what it means for your oral and overall health . What is pH and why does it matter? Drinking lemon juice (usually diluted in a glass of water or added to a cup of tea) is a beloved health tonic among fans of natural medicine. Potential benefits include lower cholesterol, lower inflammation in the body, and increased metabolism and energy. Lemon also contains high levels of antioxidants and vitamin C that boost your immune system. On a scale from 0-14, a pH of 7 is neutral (pure water) while numbers below 7 are acidic (unhealthy), and above 7 are basic or alkaline (healthy). Believers in holistic health blame many ailments on the body’s pH being too low or too acidic. Increasing your body’s pH is called “alkalizing.” Lemon juice in its natural state is acidic with a pH of about 2, but once metabolized it actually becomes alkaline with a pH ...
Read more