ELASTOMERIC IMPRESSION MATERIALS -POLYSULPHIDE AND CONDENSATION SILICONE

-

 ELASTOMERIC IMPRESSION MATERIALS

 - PART 1 

  • ELASTOMERIC :Rubber -like polymers that shows as elastic behaviour at the time of load application 

  • These polymer molecules have weak interaction in between (Van der wall forces)

  • They have tied together in 3D network 
4 ELASTOMERIC IMPRESSION MATERIALS:

1)POLYSULFIDE

2)CONDENSATION -POLYMERIZATION SILICONE

3)ADDITION-POLYMERISATION SILICONE

4)POLYETHER  

1)POLYSULPHIDE:
  • 1st material introduced also known as mercaptan/thiokal
Collapsible tubes :
  • Base: White colour
  • Catalyst: Brown,grey 
VISCOSITIES:
  1. Heavy
  2. Medium
  3. Putty
BASE :
  • Low molecular weight polysulphide
  • Filler (Titanium dioxide)
  • plasticizer(Dibutyl phthalate)
  • Accelerator(0.5% Sulphuric acid )
CATALYST:
  • Lead oxide
  • Filler (Titanium dioxide)
  • Plasticizer(Dibutyl phthalate)
  • Retarder(Oleic acid and Stearic acid)
Condensation polymerisation:
  • Mercaptan+lead dioxide  = polysulphide +water
CHARACTER:
  1. Water by product +polymerisation shrinkage =dimensional changes
  2. Water could cause air bubble in stone cast
  3. Hydrophobic,can be electroplated
ADVANTAGE:
  1. Modest cost
  2. Easily seen margin
  3. High tear resistance
  4. Long working time 
DISADVANTAGE:
  1. Require custom tray
  2. Stain clothing
  3. Pour within 1 hour 
2)CONDENSATION SILICONE :

Available in 3 viscosities:
  1. Putty
  2. Medium
  3. Light
PASTE:
  • 2 unequal size collapsible tube 
  • Base:Large ,Catalyst -Small
  • Putty :Jar,Catalyst :1)Liquid, 2)Paste 
BASE:
  • Polydimethylsiloxane (Hydroxy terminals)
  • Filler 
  • Colour pigment 
CATALYST:
  • Ortho Ethyl silicate 
  • Stannous octoate
  • Dimethyl siloxane +Silicate =Silicone +Ethyl alcohol
CHARACTER:
  • Condensation polymerisation 
  • Ethyl alcohol +polymerisation shrinkage =dimensional change
  • Alcohol air bubble
  • Hydrophobic ,electroplate
ADVANTAGE:
  1. Clean,pleasant 
  2. Good working time 
  3. Easily seen margin
DISADVANTAGE:
  1. Pour immediately
  2. Low tear strength
  3. Hydrophobic 
AIM OF THIS POST :

Today we started with a small introduction on what an elastomeric impression material is then we moved on to the classification of elastomeric impression and finally we discussed in detail about polysulphide and condensation silicone material ,The next post will be highlighting on addition and condensation silicone .If this post helped you learn then do let me know in the comment section below as this would motivate me to post more such content .







Contact Details :
Email:stencildent @gmail.com
Instagram:Stencildent


                             THANK YOU 









Comments

Post a Comment

Popular posts from this blog

Sterilization technique in microbiology

-
Image
HELLO! DOCTOR VANAKAM, I hope you all are doing good today we will be discussing sterilization various methods of sterilization, about dry heat sterilization and moist heat sterilization along with different methods employed, and what are the materials to be placed in this method in detail about autoclave its principle, working and of course uses. As I have had already informed you all through my previous post on the contribution of Louis Pasteur and Koch postulates if we haven't checked it out yet do check it out using this link   https://www.stencildent.com/2020/07/contributions-of-louis-pasteur-and-koch.html  wherein I would explain the importance for the need of the HOUR and always to sterilize things to and from the patients and also get geared up for the next post on SHOCK wherein I would cover the definition, types, classification along with etiology, pathogenesis, flow chart, the complication of septic shock in detail so now without any further ado lets get started. STERILI
Read more

STAGES AND STEPS IN TOOTH PREPARATION

-
Image
                      STAGES AND STEPS IN                                        TOOTH  PREPARATION                 TOOTH PREPARATION INVOLVES 2 STAGES  1) INITIAL TOOTH PREPARATION:    OUTLINE FORM AND INITIAL DEPTH PRIMARY RESISTANCE FORM  PRIMARY RETENTION FORM CONVENIENCE FORM 2) FINAL TOOTH PREPARATION  REMOVAL OF REMAINING CARIES PULP PROTECTION SECONDARY RESISTANCE AND RETENTION FORM FINISHING OF EXTERNAL WALL FINAL PROCEDURE OF CLEANING AND INSPECTING  Each stage and step is explained in detail please refer to above notes . note:please do not  download and share all rights are reserved to stencildent.
Read more

Hypersensitivity microbiology notes

-
Image
                          HYPERSENSITIVITY   hello, doctor vanakam, I hope you all are doing good, as intimated through the last post on anaerobic culture method  https://www.stencildent.com/2020/08/anaerobic-culture-methods-microbiology.html  if u haven't checked it out do read using this link without any further ado lets get started. CONTENTS: 1)Definition 2)Classification 3)type 1 hypersensitivity reaction a)1st exposure b)2nd exposure c)mediators of reaction d)late-phase reaction 4)type 4 hypersensitivity 5)treatment  1)DEFINITION: It refers to a condition in which immune response results in excessive reaction leading to tissue damage, disease, or even death in a sensitised host. 2) CLASSIFICATION: Coomb and gel classification in 1963 into type 1 to 4  Type 1,    type 2, type 3       : They depend on the interaction of antigen with humoral antibodies They are the immediate-type reaction  type 4 : They are mediated by t lymphocyte Delayed-type of hypersensitive reaction 3)TYPE 1
Read more