SlideShare uma empresa Scribd logo
1 de 3
What is Smear Layer?
THE SMEAR PHENOMENON:
Significant amounts of energy are expended at the interface of a substrate
and a tool during cutting and abrading. The generation of frictional heat and
plastic and elastic deformation can all contribute potentially to alteration and
deterioration of the substrate. Grinding debris from the substrate or the tool itself
may be deposited or smeared upon the work surface. Such smeared contaminants
lower the surface energy and therefore have a profound effect upon the reactivity
of the substrate surface.
In a dental context Eirich (1976) stated that smearing occurs when
“hydroxyapatite within (the tissue) is either plucked out or broken, or swept along
and resets in the smeared-out matrix”. Hard dental tissues are heterogeneous,
comprising submicroscopic crystallites of apatite enveloped in an organic matrix.
Significant variations in the proportions of these components exist between
enamel, dentin and cementum, thus contributing to a wide range of topographical
anomalies, which can be related the type of instrumentation and the manner and
conditions under which it is used.
THE SMEAR LAYER:
According to the Operative Dentistry Journal, 1984, the term smear layer
applies to “any debris produced iatrogenically by the cutting, not only of dentin,
but also of enamel, cementum and even the dentin of the root canal”.
It is defined by Anusavice (Philip’s Science of Dental Materials) as:
“Tenacious deposit of microscopic debris that covers enamel and dentin surfaces
that have been prepared for a restoration”
It has been described by Sturdevant as:
“Grinding produces gross mechanical roughness but leaves a smear layer of
hydroxyapatite crystals and denatured collagen that is approximately 1 to 3 µm
thick”.
8
What is Smear Layer?
According to the American Association of Endodontists’ (1994) glossary
Contemporary Terminology for Endodontics, the smear layer is defined as “a
surface film of debris retained on dentine or other surfaces after instrumentation
with either rotary instruments or endodontic files; consists of dentine particles,
remnants of vital or necrotic pulp tissue, bacterial components and retained
irrigant ”.
It is defined by Cohen as:
“The cutting of dentin during cavity preparation produces microcrystalline
grinding debris that coats the dentin and clogs the orifices of the dentinal tubules.
This layer of debris is termed as smear layer”
When tooth structures are cut, instead of being uniformly sheared, the
mineralized matrix shatters. Considerable quantities of cutting debris, made up of
very small particles of mineralized collagen matrix, are produced. Existing at the
strategic interface of restorative materials, and the dentin matrix, most of the
debris are scattered over the enamel and dentin surfaces to form what is known as
the smear layer. A much used analogy compares the smear layer to a clump of
wet saw dust on a cut log.
In Endodontics, the smear layer results directly from the instrumentation
used to prepare the canal wall and are found only where the walls are prepared
and not in uninstrumented areas, as studies have shown that current methods of
cleaning and shaping root canals, may not cleanse the entire root canal system,
especially in irregular and/or curved canals. In addition to superficial debris, it has
been shown, using the scanning electron microscope, that a layer of sludge
material was always formed over the surface of dentinal walls whenever dentin
was cut (Boyde and Knight, 1970; McComb and Smith, 1975; Mader et al,
1984) and this layer was called “smear layer”. The amount of smear layer
produced by automatic preparation will be greater in volume than produced by
finger filing.
9
What is Smear Layer?
Because it is a very thin layer and is soluble in acid, the smear layer will not
be apparent on routinely processed specimens examined with the light
microscope. this may be the reason why the smear layer received so little attention
by restorative dentists. When examined by the scanning electron microscope, the
smear layer will rarely be discernible on specimens of demineralized teeth
because it will be dissolved during the process of demineralization.
Undemineralized specimens will appear on electron microscopic examination as a
uniform sludge, relatively smooth and featureless.
The presence or absence of the smear layer in Endodontics is important.
When a canal is instrumented, the smear layer produced will remain within the
canal and pulp chamber. The bacteria and bacterial products found in the smear
layer can provide a reservoir of potential irritants. With this thought in mind, the
complete removal of the layer and its corps of inhabitants has been the subject of
numerous investigations.
Another source of indecisiveness about keeping or removing the smear layer
was its long-term stability. The smear layer and its provisional tenacity is a
separate structure from the underlying dentin. It may crack open and pull away
from the underlying dentinal tubules. A situation such as this would be deadly to
the foundation of gutta percha obturated over the smear layer. Thus, it was
axiomatic that removal of the smear layer permits a better adaptation of sealers
and obturating materials in the dentin.
10

Mais conteúdo relacionado

Mais procurados

Microleakage/ orthodontic course by indian dental academy
Microleakage/ orthodontic course by indian dental academyMicroleakage/ orthodontic course by indian dental academy
Microleakage/ orthodontic course by indian dental academyIndian dental academy
 
Methods of detecting microleakage/ orthodontic course by indian dental academy
Methods of detecting microleakage/ orthodontic course by indian dental academyMethods of detecting microleakage/ orthodontic course by indian dental academy
Methods of detecting microleakage/ orthodontic course by indian dental academyIndian dental academy
 
Techniques of direct composite restoration
Techniques of direct composite restorationTechniques of direct composite restoration
Techniques of direct composite restorationMrinaliniDr
 
DENTIN BONDING AGENTS
DENTIN BONDING AGENTSDENTIN BONDING AGENTS
DENTIN BONDING AGENTSTaduri Vivek
 
Bonding agents and its application in prosthodontics / dental implant courses
Bonding agents and its application in prosthodontics / dental implant coursesBonding agents and its application in prosthodontics / dental implant courses
Bonding agents and its application in prosthodontics / dental implant coursesIndian dental academy
 
Pit and fissure sealants
Pit and fissure sealantsPit and fissure sealants
Pit and fissure sealantsRamniq Kaur
 
Fundamental concepts of enamel and dentin adhesion
Fundamental concepts of enamel and dentin adhesionFundamental concepts of enamel and dentin adhesion
Fundamental concepts of enamel and dentin adhesionRicha Singh
 
Ppt fisssure sealant
Ppt fisssure sealantPpt fisssure sealant
Ppt fisssure sealantIzhar Ali
 
Bonding to Enamel and Dentin Bonding to Enamel and Dentin
Bonding to Enamel and Dentin Bonding to Enamel and DentinBonding to Enamel and Dentin Bonding to Enamel and Dentin
Bonding to Enamel and Dentin Bonding to Enamel and DentinStephanie Chahrouk
 
Dentin bonding agent /certified fixed orthodontic courses by Indian dental ac...
Dentin bonding agent /certified fixed orthodontic courses by Indian dental ac...Dentin bonding agent /certified fixed orthodontic courses by Indian dental ac...
Dentin bonding agent /certified fixed orthodontic courses by Indian dental ac...Indian dental academy
 
Pit & fissure sealants
Pit & fissure sealantsPit & fissure sealants
Pit & fissure sealantsDr Kirty Anand
 
Bonding to enamel and dentin
Bonding to enamel and dentinBonding to enamel and dentin
Bonding to enamel and dentinNivedha Tina
 
Pit and fissure sealants
Pit and fissure sealantsPit and fissure sealants
Pit and fissure sealantsDocdhingra
 

Mais procurados (20)

Smear layer
Smear layerSmear layer
Smear layer
 
Microleakage/ orthodontic course by indian dental academy
Microleakage/ orthodontic course by indian dental academyMicroleakage/ orthodontic course by indian dental academy
Microleakage/ orthodontic course by indian dental academy
 
The evolution of adhesivr technique
The evolution of adhesivr techniqueThe evolution of adhesivr technique
The evolution of adhesivr technique
 
dentin bonding agents
dentin bonding agentsdentin bonding agents
dentin bonding agents
 
Methods of detecting microleakage/ orthodontic course by indian dental academy
Methods of detecting microleakage/ orthodontic course by indian dental academyMethods of detecting microleakage/ orthodontic course by indian dental academy
Methods of detecting microleakage/ orthodontic course by indian dental academy
 
Adhesives in endodontics
Adhesives in endodonticsAdhesives in endodontics
Adhesives in endodontics
 
Bond
BondBond
Bond
 
Techniques of direct composite restoration
Techniques of direct composite restorationTechniques of direct composite restoration
Techniques of direct composite restoration
 
DENTIN BONDING AGENTS
DENTIN BONDING AGENTSDENTIN BONDING AGENTS
DENTIN BONDING AGENTS
 
bonding to enamel & dentin
bonding to enamel & dentinbonding to enamel & dentin
bonding to enamel & dentin
 
Bonding agents and its application in prosthodontics / dental implant courses
Bonding agents and its application in prosthodontics / dental implant coursesBonding agents and its application in prosthodontics / dental implant courses
Bonding agents and its application in prosthodontics / dental implant courses
 
Pit and fissure sealants
Pit and fissure sealantsPit and fissure sealants
Pit and fissure sealants
 
Bonding (2)
Bonding (2)Bonding (2)
Bonding (2)
 
Fundamental concepts of enamel and dentin adhesion
Fundamental concepts of enamel and dentin adhesionFundamental concepts of enamel and dentin adhesion
Fundamental concepts of enamel and dentin adhesion
 
Ppt fisssure sealant
Ppt fisssure sealantPpt fisssure sealant
Ppt fisssure sealant
 
Bonding to Enamel and Dentin Bonding to Enamel and Dentin
Bonding to Enamel and Dentin Bonding to Enamel and DentinBonding to Enamel and Dentin Bonding to Enamel and Dentin
Bonding to Enamel and Dentin Bonding to Enamel and Dentin
 
Dentin bonding agent /certified fixed orthodontic courses by Indian dental ac...
Dentin bonding agent /certified fixed orthodontic courses by Indian dental ac...Dentin bonding agent /certified fixed orthodontic courses by Indian dental ac...
Dentin bonding agent /certified fixed orthodontic courses by Indian dental ac...
 
Pit & fissure sealants
Pit & fissure sealantsPit & fissure sealants
Pit & fissure sealants
 
Bonding to enamel and dentin
Bonding to enamel and dentinBonding to enamel and dentin
Bonding to enamel and dentin
 
Pit and fissure sealants
Pit and fissure sealantsPit and fissure sealants
Pit and fissure sealants
 

Destaque

The Smear layer in endodontics
The Smear layer in endodonticsThe Smear layer in endodontics
The Smear layer in endodonticsDr. Arpit Viradiya
 
removal of the smear layer /rotary endodontic courses by indian dental academy
removal of the smear layer /rotary endodontic courses by indian dental academyremoval of the smear layer /rotary endodontic courses by indian dental academy
removal of the smear layer /rotary endodontic courses by indian dental academyIndian dental academy
 
Sodium hypochlorite
Sodium hypochloriteSodium hypochlorite
Sodium hypochloriteAnoop Nair
 
Endodontic irrigating solutions
Endodontic irrigating solutionsEndodontic irrigating solutions
Endodontic irrigating solutionsMarwa Ahmed
 

Destaque (6)

The Smear layer in endodontics
The Smear layer in endodonticsThe Smear layer in endodontics
The Smear layer in endodontics
 
removal of the smear layer /rotary endodontic courses by indian dental academy
removal of the smear layer /rotary endodontic courses by indian dental academyremoval of the smear layer /rotary endodontic courses by indian dental academy
removal of the smear layer /rotary endodontic courses by indian dental academy
 
Sodium hypochlorite
Sodium hypochloriteSodium hypochlorite
Sodium hypochlorite
 
Dentistry mcqs
Dentistry mcqsDentistry mcqs
Dentistry mcqs
 
Endodontic irrigating solutions
Endodontic irrigating solutionsEndodontic irrigating solutions
Endodontic irrigating solutions
 
Irrigation in endodontics
Irrigation in endodonticsIrrigation in endodontics
Irrigation in endodontics
 

Semelhante a what is smear layer/rotary endodontic courses by indian dental academy

Veneers /certified fixed orthodontic courses by Indian dental academy
Veneers  /certified fixed orthodontic courses by Indian   dental academy Veneers  /certified fixed orthodontic courses by Indian   dental academy
Veneers /certified fixed orthodontic courses by Indian dental academy Indian dental academy
 
Dentin bonding agents sneha
Dentin bonding agents snehaDentin bonding agents sneha
Dentin bonding agents snehaSNEHA RATNANI
 
posterior direct composite restoration
posterior direct composite restorationposterior direct composite restoration
posterior direct composite restorationAzheen Mohamad Kharib
 
Pit and fissure sealants
 Pit and fissure sealants  Pit and fissure sealants
Pit and fissure sealants Drpalki
 
Pulp protection in operative dentistry
Pulp protection in operative dentistry Pulp protection in operative dentistry
Pulp protection in operative dentistry Nivedha Tina
 
Composite bonding adhesive system
Composite bonding adhesive system Composite bonding adhesive system
Composite bonding adhesive system Ibrahim Muneim
 
final prof lecture on pit and fissure sealant.pptx
final prof lecture on pit and fissure sealant.pptxfinal prof lecture on pit and fissure sealant.pptx
final prof lecture on pit and fissure sealant.pptxpedodonticsdepartmen1
 
Enamel clinical aspect sagar hiwale
Enamel clinical aspect  sagar hiwaleEnamel clinical aspect  sagar hiwale
Enamel clinical aspect sagar hiwaleSAGAR HIWALE
 
Adhesion in restorative dentistry
Adhesion in restorative dentistryAdhesion in restorative dentistry
Adhesion in restorative dentistryIAU Dent
 
Bonding agents2/ dental crown & bridge courses
Bonding agents2/ dental crown & bridge coursesBonding agents2/ dental crown & bridge courses
Bonding agents2/ dental crown & bridge coursesIndian dental academy
 
Investigation of the Remineralization Effect Tnrough Scanning Electron Micros...
Investigation of the Remineralization Effect Tnrough Scanning Electron Micros...Investigation of the Remineralization Effect Tnrough Scanning Electron Micros...
Investigation of the Remineralization Effect Tnrough Scanning Electron Micros...IJERA Editor
 
Nanotechnology/ dental implant courses
Nanotechnology/ dental implant coursesNanotechnology/ dental implant courses
Nanotechnology/ dental implant coursesIndian dental academy
 

Semelhante a what is smear layer/rotary endodontic courses by indian dental academy (20)

The Smear Layer
The Smear LayerThe Smear Layer
The Smear Layer
 
Veneers /certified fixed orthodontic courses by Indian dental academy
Veneers  /certified fixed orthodontic courses by Indian   dental academy Veneers  /certified fixed orthodontic courses by Indian   dental academy
Veneers /certified fixed orthodontic courses by Indian dental academy
 
Dentin bonding agents sneha
Dentin bonding agents snehaDentin bonding agents sneha
Dentin bonding agents sneha
 
Veneers/ fixed orthodontics courses
Veneers/ fixed orthodontics coursesVeneers/ fixed orthodontics courses
Veneers/ fixed orthodontics courses
 
posterior direct composite restoration
posterior direct composite restorationposterior direct composite restoration
posterior direct composite restoration
 
Adhesion and Dentin Bonding agent
Adhesion and Dentin Bonding agentAdhesion and Dentin Bonding agent
Adhesion and Dentin Bonding agent
 
Pit and fissure sealants
 Pit and fissure sealants  Pit and fissure sealants
Pit and fissure sealants
 
Pulp protection in operative dentistry
Pulp protection in operative dentistry Pulp protection in operative dentistry
Pulp protection in operative dentistry
 
Composite bonding adhesive system
Composite bonding adhesive system Composite bonding adhesive system
Composite bonding adhesive system
 
Veneers /prosthodontic courses
Veneers /prosthodontic coursesVeneers /prosthodontic courses
Veneers /prosthodontic courses
 
Dentin bonding agents
Dentin bonding agentsDentin bonding agents
Dentin bonding agents
 
final prof lecture on pit and fissure sealant.pptx
final prof lecture on pit and fissure sealant.pptxfinal prof lecture on pit and fissure sealant.pptx
final prof lecture on pit and fissure sealant.pptx
 
Enamel clinical aspect sagar hiwale
Enamel clinical aspect  sagar hiwaleEnamel clinical aspect  sagar hiwale
Enamel clinical aspect sagar hiwale
 
Adhesion in restorative dentistry
Adhesion in restorative dentistryAdhesion in restorative dentistry
Adhesion in restorative dentistry
 
Scanning electron microscope
Scanning electron microscopeScanning electron microscope
Scanning electron microscope
 
Bonding agents2/ dental crown & bridge courses
Bonding agents2/ dental crown & bridge coursesBonding agents2/ dental crown & bridge courses
Bonding agents2/ dental crown & bridge courses
 
Bonding agents2/ dental courses
Bonding agents2/ dental coursesBonding agents2/ dental courses
Bonding agents2/ dental courses
 
Investigation of the Remineralization Effect Tnrough Scanning Electron Micros...
Investigation of the Remineralization Effect Tnrough Scanning Electron Micros...Investigation of the Remineralization Effect Tnrough Scanning Electron Micros...
Investigation of the Remineralization Effect Tnrough Scanning Electron Micros...
 
Nanotechnology/ dental implant courses
Nanotechnology/ dental implant coursesNanotechnology/ dental implant courses
Nanotechnology/ dental implant courses
 
Interproximal enamel reduction
Interproximal enamel reductionInterproximal enamel reduction
Interproximal enamel reduction
 

Mais de Indian dental academy

Indian Dentist - relocate to united kingdom
Indian Dentist - relocate to united kingdomIndian Dentist - relocate to united kingdom
Indian Dentist - relocate to united kingdomIndian dental academy
 
1ST, 2ND AND 3RD ORDER BENDS IN STANDARD EDGEWISE APPLIANCE SYSTEM /Fixed ort...
1ST, 2ND AND 3RD ORDER BENDS IN STANDARD EDGEWISE APPLIANCE SYSTEM /Fixed ort...1ST, 2ND AND 3RD ORDER BENDS IN STANDARD EDGEWISE APPLIANCE SYSTEM /Fixed ort...
1ST, 2ND AND 3RD ORDER BENDS IN STANDARD EDGEWISE APPLIANCE SYSTEM /Fixed ort...Indian dental academy
 
Invisalign -invisible aligners course in india
Invisalign -invisible aligners course in india Invisalign -invisible aligners course in india
Invisalign -invisible aligners course in india Indian dental academy
 
Invisible aligners for your orthodontics pratice
Invisible aligners for your orthodontics praticeInvisible aligners for your orthodontics pratice
Invisible aligners for your orthodontics praticeIndian dental academy
 
Development of muscles of mastication / dental implant courses
Development of muscles of mastication / dental implant coursesDevelopment of muscles of mastication / dental implant courses
Development of muscles of mastication / dental implant coursesIndian dental academy
 
Corticosteriods uses in dentistry/ oral surgery courses  
Corticosteriods uses in dentistry/ oral surgery courses  Corticosteriods uses in dentistry/ oral surgery courses  
Corticosteriods uses in dentistry/ oral surgery courses  Indian dental academy
 
Cytotoxicity of silicone materials used in maxillofacial prosthesis / dental ...
Cytotoxicity of silicone materials used in maxillofacial prosthesis / dental ...Cytotoxicity of silicone materials used in maxillofacial prosthesis / dental ...
Cytotoxicity of silicone materials used in maxillofacial prosthesis / dental ...Indian dental academy
 
Diagnosis and treatment planning in completely endntulous arches/dental courses
Diagnosis and treatment planning in completely endntulous arches/dental coursesDiagnosis and treatment planning in completely endntulous arches/dental courses
Diagnosis and treatment planning in completely endntulous arches/dental coursesIndian dental academy
 
Properties of Denture base materials /rotary endodontic courses
Properties of Denture base materials /rotary endodontic coursesProperties of Denture base materials /rotary endodontic courses
Properties of Denture base materials /rotary endodontic coursesIndian dental academy
 
Use of modified tooth forms in complete denture occlusion / dental implant...
Use of modified  tooth forms  in  complete denture occlusion / dental implant...Use of modified  tooth forms  in  complete denture occlusion / dental implant...
Use of modified tooth forms in complete denture occlusion / dental implant...Indian dental academy
 
Dental luting cements / oral surgery courses  
Dental   luting cements / oral surgery courses  Dental   luting cements / oral surgery courses  
Dental luting cements / oral surgery courses  Indian dental academy
 
Dental casting alloys/ oral surgery courses  
Dental casting alloys/ oral surgery courses  Dental casting alloys/ oral surgery courses  
Dental casting alloys/ oral surgery courses  Indian dental academy
 
Dental casting investment materials/endodontic courses
Dental casting investment materials/endodontic coursesDental casting investment materials/endodontic courses
Dental casting investment materials/endodontic coursesIndian dental academy
 
Dental casting waxes/ oral surgery courses  
Dental casting waxes/ oral surgery courses  Dental casting waxes/ oral surgery courses  
Dental casting waxes/ oral surgery courses  Indian dental academy
 
Dental ceramics/prosthodontic courses
Dental ceramics/prosthodontic coursesDental ceramics/prosthodontic courses
Dental ceramics/prosthodontic coursesIndian dental academy
 
Dental implant/ oral surgery courses  
Dental implant/ oral surgery courses  Dental implant/ oral surgery courses  
Dental implant/ oral surgery courses  Indian dental academy
 
Dental perspective/cosmetic dentistry courses
Dental perspective/cosmetic dentistry coursesDental perspective/cosmetic dentistry courses
Dental perspective/cosmetic dentistry coursesIndian dental academy
 
Dental tissues and their replacements/ oral surgery courses  
Dental tissues and their replacements/ oral surgery courses  Dental tissues and their replacements/ oral surgery courses  
Dental tissues and their replacements/ oral surgery courses  Indian dental academy
 

Mais de Indian dental academy (20)

Indian Dentist - relocate to united kingdom
Indian Dentist - relocate to united kingdomIndian Dentist - relocate to united kingdom
Indian Dentist - relocate to united kingdom
 
1ST, 2ND AND 3RD ORDER BENDS IN STANDARD EDGEWISE APPLIANCE SYSTEM /Fixed ort...
1ST, 2ND AND 3RD ORDER BENDS IN STANDARD EDGEWISE APPLIANCE SYSTEM /Fixed ort...1ST, 2ND AND 3RD ORDER BENDS IN STANDARD EDGEWISE APPLIANCE SYSTEM /Fixed ort...
1ST, 2ND AND 3RD ORDER BENDS IN STANDARD EDGEWISE APPLIANCE SYSTEM /Fixed ort...
 
Invisalign -invisible aligners course in india
Invisalign -invisible aligners course in india Invisalign -invisible aligners course in india
Invisalign -invisible aligners course in india
 
Invisible aligners for your orthodontics pratice
Invisible aligners for your orthodontics praticeInvisible aligners for your orthodontics pratice
Invisible aligners for your orthodontics pratice
 
online fixed orthodontics course
online fixed orthodontics courseonline fixed orthodontics course
online fixed orthodontics course
 
online orthodontics course
online orthodontics courseonline orthodontics course
online orthodontics course
 
Development of muscles of mastication / dental implant courses
Development of muscles of mastication / dental implant coursesDevelopment of muscles of mastication / dental implant courses
Development of muscles of mastication / dental implant courses
 
Corticosteriods uses in dentistry/ oral surgery courses  
Corticosteriods uses in dentistry/ oral surgery courses  Corticosteriods uses in dentistry/ oral surgery courses  
Corticosteriods uses in dentistry/ oral surgery courses  
 
Cytotoxicity of silicone materials used in maxillofacial prosthesis / dental ...
Cytotoxicity of silicone materials used in maxillofacial prosthesis / dental ...Cytotoxicity of silicone materials used in maxillofacial prosthesis / dental ...
Cytotoxicity of silicone materials used in maxillofacial prosthesis / dental ...
 
Diagnosis and treatment planning in completely endntulous arches/dental courses
Diagnosis and treatment planning in completely endntulous arches/dental coursesDiagnosis and treatment planning in completely endntulous arches/dental courses
Diagnosis and treatment planning in completely endntulous arches/dental courses
 
Properties of Denture base materials /rotary endodontic courses
Properties of Denture base materials /rotary endodontic coursesProperties of Denture base materials /rotary endodontic courses
Properties of Denture base materials /rotary endodontic courses
 
Use of modified tooth forms in complete denture occlusion / dental implant...
Use of modified  tooth forms  in  complete denture occlusion / dental implant...Use of modified  tooth forms  in  complete denture occlusion / dental implant...
Use of modified tooth forms in complete denture occlusion / dental implant...
 
Dental luting cements / oral surgery courses  
Dental   luting cements / oral surgery courses  Dental   luting cements / oral surgery courses  
Dental luting cements / oral surgery courses  
 
Dental casting alloys/ oral surgery courses  
Dental casting alloys/ oral surgery courses  Dental casting alloys/ oral surgery courses  
Dental casting alloys/ oral surgery courses  
 
Dental casting investment materials/endodontic courses
Dental casting investment materials/endodontic coursesDental casting investment materials/endodontic courses
Dental casting investment materials/endodontic courses
 
Dental casting waxes/ oral surgery courses  
Dental casting waxes/ oral surgery courses  Dental casting waxes/ oral surgery courses  
Dental casting waxes/ oral surgery courses  
 
Dental ceramics/prosthodontic courses
Dental ceramics/prosthodontic coursesDental ceramics/prosthodontic courses
Dental ceramics/prosthodontic courses
 
Dental implant/ oral surgery courses  
Dental implant/ oral surgery courses  Dental implant/ oral surgery courses  
Dental implant/ oral surgery courses  
 
Dental perspective/cosmetic dentistry courses
Dental perspective/cosmetic dentistry coursesDental perspective/cosmetic dentistry courses
Dental perspective/cosmetic dentistry courses
 
Dental tissues and their replacements/ oral surgery courses  
Dental tissues and their replacements/ oral surgery courses  Dental tissues and their replacements/ oral surgery courses  
Dental tissues and their replacements/ oral surgery courses  
 

Último

How to Show Error_Warning Messages in Odoo 17
How to Show Error_Warning Messages in Odoo 17How to Show Error_Warning Messages in Odoo 17
How to Show Error_Warning Messages in Odoo 17Celine George
 
Prescribed medication order and communication skills.pptx
Prescribed medication order and communication skills.pptxPrescribed medication order and communication skills.pptx
Prescribed medication order and communication skills.pptxraviapr7
 
How to Use api.constrains ( ) in Odoo 17
How to Use api.constrains ( ) in Odoo 17How to Use api.constrains ( ) in Odoo 17
How to Use api.constrains ( ) in Odoo 17Celine George
 
How to Manage Cross-Selling in Odoo 17 Sales
How to Manage Cross-Selling in Odoo 17 SalesHow to Manage Cross-Selling in Odoo 17 Sales
How to Manage Cross-Selling in Odoo 17 SalesCeline George
 
3.21.24 The Origins of Black Power.pptx
3.21.24  The Origins of Black Power.pptx3.21.24  The Origins of Black Power.pptx
3.21.24 The Origins of Black Power.pptxmary850239
 
Presentation on the Basics of Writing. Writing a Paragraph
Presentation on the Basics of Writing. Writing a ParagraphPresentation on the Basics of Writing. Writing a Paragraph
Presentation on the Basics of Writing. Writing a ParagraphNetziValdelomar1
 
M-2- General Reactions of amino acids.pptx
M-2- General Reactions of amino acids.pptxM-2- General Reactions of amino acids.pptx
M-2- General Reactions of amino acids.pptxDr. Santhosh Kumar. N
 
PISA-VET launch_El Iza Mohamedou_19 March 2024.pptx
PISA-VET launch_El Iza Mohamedou_19 March 2024.pptxPISA-VET launch_El Iza Mohamedou_19 March 2024.pptx
PISA-VET launch_El Iza Mohamedou_19 March 2024.pptxEduSkills OECD
 
Easter in the USA presentation by Chloe.
Easter in the USA presentation by Chloe.Easter in the USA presentation by Chloe.
Easter in the USA presentation by Chloe.EnglishCEIPdeSigeiro
 
Philosophy of Education and Educational Philosophy
Philosophy of Education  and Educational PhilosophyPhilosophy of Education  and Educational Philosophy
Philosophy of Education and Educational PhilosophyShuvankar Madhu
 
2024.03.23 What do successful readers do - Sandy Millin for PARK.pptx
2024.03.23 What do successful readers do - Sandy Millin for PARK.pptx2024.03.23 What do successful readers do - Sandy Millin for PARK.pptx
2024.03.23 What do successful readers do - Sandy Millin for PARK.pptxSandy Millin
 
General views of Histopathology and step
General views of Histopathology and stepGeneral views of Histopathology and step
General views of Histopathology and stepobaje godwin sunday
 
Human-AI Co-Creation of Worked Examples for Programming Classes
Human-AI Co-Creation of Worked Examples for Programming ClassesHuman-AI Co-Creation of Worked Examples for Programming Classes
Human-AI Co-Creation of Worked Examples for Programming ClassesMohammad Hassany
 
Quality Assurance_GOOD LABORATORY PRACTICE
Quality Assurance_GOOD LABORATORY PRACTICEQuality Assurance_GOOD LABORATORY PRACTICE
Quality Assurance_GOOD LABORATORY PRACTICESayali Powar
 
Education and training program in the hospital APR.pptx
Education and training program in the hospital APR.pptxEducation and training program in the hospital APR.pptx
Education and training program in the hospital APR.pptxraviapr7
 
Practical Research 1: Lesson 8 Writing the Thesis Statement.pptx
Practical Research 1: Lesson 8 Writing the Thesis Statement.pptxPractical Research 1: Lesson 8 Writing the Thesis Statement.pptx
Practical Research 1: Lesson 8 Writing the Thesis Statement.pptxKatherine Villaluna
 
CHUYÊN ĐỀ DẠY THÊM TIẾNG ANH LỚP 11 - GLOBAL SUCCESS - NĂM HỌC 2023-2024 - HK...
CHUYÊN ĐỀ DẠY THÊM TIẾNG ANH LỚP 11 - GLOBAL SUCCESS - NĂM HỌC 2023-2024 - HK...CHUYÊN ĐỀ DẠY THÊM TIẾNG ANH LỚP 11 - GLOBAL SUCCESS - NĂM HỌC 2023-2024 - HK...
CHUYÊN ĐỀ DẠY THÊM TIẾNG ANH LỚP 11 - GLOBAL SUCCESS - NĂM HỌC 2023-2024 - HK...Nguyen Thanh Tu Collection
 
What is the Future of QuickBooks DeskTop?
What is the Future of QuickBooks DeskTop?What is the Future of QuickBooks DeskTop?
What is the Future of QuickBooks DeskTop?TechSoup
 
The Singapore Teaching Practice document
The Singapore Teaching Practice documentThe Singapore Teaching Practice document
The Singapore Teaching Practice documentXsasf Sfdfasd
 

Último (20)

How to Show Error_Warning Messages in Odoo 17
How to Show Error_Warning Messages in Odoo 17How to Show Error_Warning Messages in Odoo 17
How to Show Error_Warning Messages in Odoo 17
 
Prescribed medication order and communication skills.pptx
Prescribed medication order and communication skills.pptxPrescribed medication order and communication skills.pptx
Prescribed medication order and communication skills.pptx
 
How to Use api.constrains ( ) in Odoo 17
How to Use api.constrains ( ) in Odoo 17How to Use api.constrains ( ) in Odoo 17
How to Use api.constrains ( ) in Odoo 17
 
How to Manage Cross-Selling in Odoo 17 Sales
How to Manage Cross-Selling in Odoo 17 SalesHow to Manage Cross-Selling in Odoo 17 Sales
How to Manage Cross-Selling in Odoo 17 Sales
 
3.21.24 The Origins of Black Power.pptx
3.21.24  The Origins of Black Power.pptx3.21.24  The Origins of Black Power.pptx
3.21.24 The Origins of Black Power.pptx
 
Presentation on the Basics of Writing. Writing a Paragraph
Presentation on the Basics of Writing. Writing a ParagraphPresentation on the Basics of Writing. Writing a Paragraph
Presentation on the Basics of Writing. Writing a Paragraph
 
M-2- General Reactions of amino acids.pptx
M-2- General Reactions of amino acids.pptxM-2- General Reactions of amino acids.pptx
M-2- General Reactions of amino acids.pptx
 
PISA-VET launch_El Iza Mohamedou_19 March 2024.pptx
PISA-VET launch_El Iza Mohamedou_19 March 2024.pptxPISA-VET launch_El Iza Mohamedou_19 March 2024.pptx
PISA-VET launch_El Iza Mohamedou_19 March 2024.pptx
 
Personal Resilience in Project Management 2 - TV Edit 1a.pdf
Personal Resilience in Project Management 2 - TV Edit 1a.pdfPersonal Resilience in Project Management 2 - TV Edit 1a.pdf
Personal Resilience in Project Management 2 - TV Edit 1a.pdf
 
Easter in the USA presentation by Chloe.
Easter in the USA presentation by Chloe.Easter in the USA presentation by Chloe.
Easter in the USA presentation by Chloe.
 
Philosophy of Education and Educational Philosophy
Philosophy of Education  and Educational PhilosophyPhilosophy of Education  and Educational Philosophy
Philosophy of Education and Educational Philosophy
 
2024.03.23 What do successful readers do - Sandy Millin for PARK.pptx
2024.03.23 What do successful readers do - Sandy Millin for PARK.pptx2024.03.23 What do successful readers do - Sandy Millin for PARK.pptx
2024.03.23 What do successful readers do - Sandy Millin for PARK.pptx
 
General views of Histopathology and step
General views of Histopathology and stepGeneral views of Histopathology and step
General views of Histopathology and step
 
Human-AI Co-Creation of Worked Examples for Programming Classes
Human-AI Co-Creation of Worked Examples for Programming ClassesHuman-AI Co-Creation of Worked Examples for Programming Classes
Human-AI Co-Creation of Worked Examples for Programming Classes
 
Quality Assurance_GOOD LABORATORY PRACTICE
Quality Assurance_GOOD LABORATORY PRACTICEQuality Assurance_GOOD LABORATORY PRACTICE
Quality Assurance_GOOD LABORATORY PRACTICE
 
Education and training program in the hospital APR.pptx
Education and training program in the hospital APR.pptxEducation and training program in the hospital APR.pptx
Education and training program in the hospital APR.pptx
 
Practical Research 1: Lesson 8 Writing the Thesis Statement.pptx
Practical Research 1: Lesson 8 Writing the Thesis Statement.pptxPractical Research 1: Lesson 8 Writing the Thesis Statement.pptx
Practical Research 1: Lesson 8 Writing the Thesis Statement.pptx
 
CHUYÊN ĐỀ DẠY THÊM TIẾNG ANH LỚP 11 - GLOBAL SUCCESS - NĂM HỌC 2023-2024 - HK...
CHUYÊN ĐỀ DẠY THÊM TIẾNG ANH LỚP 11 - GLOBAL SUCCESS - NĂM HỌC 2023-2024 - HK...CHUYÊN ĐỀ DẠY THÊM TIẾNG ANH LỚP 11 - GLOBAL SUCCESS - NĂM HỌC 2023-2024 - HK...
CHUYÊN ĐỀ DẠY THÊM TIẾNG ANH LỚP 11 - GLOBAL SUCCESS - NĂM HỌC 2023-2024 - HK...
 
What is the Future of QuickBooks DeskTop?
What is the Future of QuickBooks DeskTop?What is the Future of QuickBooks DeskTop?
What is the Future of QuickBooks DeskTop?
 
The Singapore Teaching Practice document
The Singapore Teaching Practice documentThe Singapore Teaching Practice document
The Singapore Teaching Practice document
 

what is smear layer/rotary endodontic courses by indian dental academy

  • 1. What is Smear Layer? THE SMEAR PHENOMENON: Significant amounts of energy are expended at the interface of a substrate and a tool during cutting and abrading. The generation of frictional heat and plastic and elastic deformation can all contribute potentially to alteration and deterioration of the substrate. Grinding debris from the substrate or the tool itself may be deposited or smeared upon the work surface. Such smeared contaminants lower the surface energy and therefore have a profound effect upon the reactivity of the substrate surface. In a dental context Eirich (1976) stated that smearing occurs when “hydroxyapatite within (the tissue) is either plucked out or broken, or swept along and resets in the smeared-out matrix”. Hard dental tissues are heterogeneous, comprising submicroscopic crystallites of apatite enveloped in an organic matrix. Significant variations in the proportions of these components exist between enamel, dentin and cementum, thus contributing to a wide range of topographical anomalies, which can be related the type of instrumentation and the manner and conditions under which it is used. THE SMEAR LAYER: According to the Operative Dentistry Journal, 1984, the term smear layer applies to “any debris produced iatrogenically by the cutting, not only of dentin, but also of enamel, cementum and even the dentin of the root canal”. It is defined by Anusavice (Philip’s Science of Dental Materials) as: “Tenacious deposit of microscopic debris that covers enamel and dentin surfaces that have been prepared for a restoration” It has been described by Sturdevant as: “Grinding produces gross mechanical roughness but leaves a smear layer of hydroxyapatite crystals and denatured collagen that is approximately 1 to 3 µm thick”. 8
  • 2. What is Smear Layer? According to the American Association of Endodontists’ (1994) glossary Contemporary Terminology for Endodontics, the smear layer is defined as “a surface film of debris retained on dentine or other surfaces after instrumentation with either rotary instruments or endodontic files; consists of dentine particles, remnants of vital or necrotic pulp tissue, bacterial components and retained irrigant ”. It is defined by Cohen as: “The cutting of dentin during cavity preparation produces microcrystalline grinding debris that coats the dentin and clogs the orifices of the dentinal tubules. This layer of debris is termed as smear layer” When tooth structures are cut, instead of being uniformly sheared, the mineralized matrix shatters. Considerable quantities of cutting debris, made up of very small particles of mineralized collagen matrix, are produced. Existing at the strategic interface of restorative materials, and the dentin matrix, most of the debris are scattered over the enamel and dentin surfaces to form what is known as the smear layer. A much used analogy compares the smear layer to a clump of wet saw dust on a cut log. In Endodontics, the smear layer results directly from the instrumentation used to prepare the canal wall and are found only where the walls are prepared and not in uninstrumented areas, as studies have shown that current methods of cleaning and shaping root canals, may not cleanse the entire root canal system, especially in irregular and/or curved canals. In addition to superficial debris, it has been shown, using the scanning electron microscope, that a layer of sludge material was always formed over the surface of dentinal walls whenever dentin was cut (Boyde and Knight, 1970; McComb and Smith, 1975; Mader et al, 1984) and this layer was called “smear layer”. The amount of smear layer produced by automatic preparation will be greater in volume than produced by finger filing. 9
  • 3. What is Smear Layer? Because it is a very thin layer and is soluble in acid, the smear layer will not be apparent on routinely processed specimens examined with the light microscope. this may be the reason why the smear layer received so little attention by restorative dentists. When examined by the scanning electron microscope, the smear layer will rarely be discernible on specimens of demineralized teeth because it will be dissolved during the process of demineralization. Undemineralized specimens will appear on electron microscopic examination as a uniform sludge, relatively smooth and featureless. The presence or absence of the smear layer in Endodontics is important. When a canal is instrumented, the smear layer produced will remain within the canal and pulp chamber. The bacteria and bacterial products found in the smear layer can provide a reservoir of potential irritants. With this thought in mind, the complete removal of the layer and its corps of inhabitants has been the subject of numerous investigations. Another source of indecisiveness about keeping or removing the smear layer was its long-term stability. The smear layer and its provisional tenacity is a separate structure from the underlying dentin. It may crack open and pull away from the underlying dentinal tubules. A situation such as this would be deadly to the foundation of gutta percha obturated over the smear layer. Thus, it was axiomatic that removal of the smear layer permits a better adaptation of sealers and obturating materials in the dentin. 10