Fall Lecture: Pulp protection Therapy: Sealers, Liners, and Bases Flashcards
Pulp protection therapy:
tx that maintains pulp tissue in healthy and functional state whenever pulp has been exposed by caries, trauma, or restorative procedures
3 types of pulpal irritants:
microbial, mechanical, chemical
Ex’s of microbial irritants:
dental caries, perio disease
Ex’s of mechanical or physical irritants:
incorrectly ortho tx, drilling, periodontal curettage
Degree of pulpal reaction depends upon:
friction and desiccation
Frictional heat from tooth prep can lead to:
burn lesions, abscess
Chemical irritants that can damage pulp:
filling materials, medicines to desensitize, dehyrate, or sterilize dentin
Goal of pulp protection therapy:
thermal, mechanical, chemical and electrical protection, sealling of dentinal tubules
Characteristics of ideal pulp protecting agent:
bio/chem compatible, non-permeable barrier on cut dentin, no effect on bulk or mech props of resto, no discoloration of tooth or resto material, sets fast enough for final resto to be completed quickly enough, low solubility in oral “builds”, ease of use during mixing and insertion
This provides the best pulpal protection:
dentin
Thickness of dentin to provide more than 90% of pulpal protection:
2mm +
Thickness of dentin to provide 90% of pulpal protection:
1mm
Thickness of dentin to provide 75% of pulpal protection:
0.5mm
Greatest damage to pulp will result in remaining dentinal thickness (RDT) of:
0.25 to 0.3mm
When to use sealers, liners, and bases:
moderate carious lesion
When to use pulp capping, either direct or indirect:
deep carious lesion
Cavity selares provide:
protective coating, leakage barrier
2 types of sealers:
varnishes and adhesive sealers
Varnish:
natural rosin or copal gum or synthetic resin, dissolved in organic solvent, acetone, chloroform, or ether
Adhesive sealers provide:
sealing and bonding
Solid component of varnish:
copal resin
Solvent component of varnish:
ether, acetone, alcohol
Indications for varnish:
Under amalgam: all walls and margins, prevents sensitivity and discoloration, zinc phosphate cement: pulpal flood, prevent acid penetration
Contraindications of varnish:
under GIC: no thermal protection, prevents adhesion to tooth, under resin restos, residual monomer will dissolve varnish, water soluble
Adhesive sealers:
multi-substrate bonding, bonds resto to tooth
Ex’s of adhesive sealers:
adhesive bonding agents, glass ionomers, resin luting cements
indications for use of adhesive sealers:
treat/prevent hypersensitivity, seal dentinal tubules, under all indirect restorations
Types of liners:
cement or resin
how thick are liners?
usually less than 0.5mm
Function of liners:
barrier to bacteria/ byproducts, therapeutic effect, such as antibacterial or pulpal anodyne (pain relieving) effect, fluoride release
Walls of prep to which liners are applied:
pulpal floor only
4 types of liners:
CaOH2, ZOE, glass ionomer Type 3, flowable composite
Base:
goes over liner (check)
2 types of calcium hydroxide cements::
self or light curing
Which has better mechanical props. light or self curing?
light, VLC dycal, polyphenolics
Advantages of CaOH2:
activates ATPse leading to dentin mineralization, stimulates reparative dentin *formation, biocompatible, pH of 12.5, neutralizes acidity/ bacterialcidal
Disadvantages to CaOH2
low stegnth, high solubility, dissolves rapidly
Function of glass ionome over the CaH2 liner:
support resto
Type I glass ionomer:
luting cement
Type II glass ionomer:
Restoration
Type III glass ionomer:
Liners and Bases
Type IV glass ionomer:
Fissure sealants
Type V glass ionomer:
ortho cements
Type VI glass ionomer:
Core builup
List the 6 types of glass ionomers:
luting, restos, liners and bases, fissure sealant, ortho cement, core buildup
Glass ionomer type used for pulp protection:
type 3, powder:aluminum silicate glass, liquid: polyalkenote acid, light cure resin
Best option for composite restos:
GIC
Advantages of GI Type III:
adhesive to tooth, anticariogenic, semi translucent, fluoride release
DisAdvantages of GI Type III:
water sorption causes leakage and discoloration, low wear or abrasion resistance
Composites with lower filler content:
flowable
Properties of flowable composite:
more fluid, less strength, less stiffness
What is a base?
replace missing dentin, used for bulk and/or for blocking out undercuts in preps for indirect restorations.
Usual thickness for base:
0.5 to 1mm
Classifications of bass:
high and low strength
High strength bases:
zinc phosphate, zinc polycarboxilate, glass ionomer (type III), reinforced ZOE
Low strength bases:
CaOH2, ZOE
Functions of a base:
chem insulator, thermal insulator at 0.75mm thickness, mechanical support to resto, distributes stress to underlying dentin
oldest luting cement:
zinc phosphate
Gold (?) standard to which newer cements are compared:
zinc phosphate
Advantages to zinc phosphate:
good mechanical props, thermail insulation
Disadvantages to zinc phosphate
does not adhere to tooth structure, exothermic reaction at initial setting that can damage pulp, opaque, not esthetic, dissolves in OC, acidic in nature
Composition of powder portion of reinforced ZOE:
zinc oxide and natural or synthetic resin
Composition of liquid portion of reinforced ZOE:
eugenol, acetic acid, thymol
Props of ZOE:
stronger than regular zinc oxide cements, less pulpal irritation, anodyne effect on pul[
When to remove sound tooth structure to provide space for base,
never
Benefits of maintaining sound dentin:
better support and pulpal protection
Uses of bases for indirect restos:
build up and block out materials for cementing indirect restos
What to be aware of when using base under amalgam or resin restos:
minimize extent of base
How much liner to use:
minimum thickness to achieve desired result
Pulp protection therapy to use when there is more than 2mm dentin thickness for amalgam resto:
varnish
Pulp protection therapy to use when there is more than 2mm dentin thickness for composite resto:
dentin bonding agent
Pulp protection therapy to use when there is more than 2mm dentin thickness for glass ionomer resto:
none
Pulp protection therapy to use when there is more than 2mm dentin thickness for cast gold resto:
none
Pulp protection therapy to use when there is 0.5mm-2mm dentin thickness for amalgam resto:
base
Pulp protection therapy to use when there is 0.5mm-2mm dentin thickness for composite resto:
dentin bonding agent
Pulp protection therapy to use when there is 0.5mm-2mm dentin thickness for glass ionomer resto:
none
Pulp protection therapy to use when there is 0.5mm-2mm dentin thickness for cast gold resto:
base
Pulp protection therapy to use when there is less than 0.5mm dentin thickness for amalgam resto:
CaOH2 and GIC
Pulp protection therapy to use when there is less than 0.5mm dentin thickness for composite resto:
CaOH2 and GIC
Pulp protection therapy to use when there is less than 0.5mm dentin thickness for glass ionomer resto:
CaOH2
Pulp protection therapy to use when there is less than 0.5mm dentin thickness for cast gold resto:
CaOH2 + base
TF? both direct and indirect pulp capping use the same 3 layers: CaOH2, GI, and resto material.
T
indirect pulp capping;
not DIRECTLY touching pulp
direct pulp capping:
direct contact with inner pulp
Pulp capping can be done if:
vital pulp, no spontaneous pain, hot/cold pulp testing pain does not linger after stimulus removal, PA with no evidince of periradicualr lesion, bacteria excluded from a site by the resto
2 major factors affect pulpal response to irritants:
rate of caries attack, pulp vitalty
This type of lesion forms more reactionary/ tertiary dentin:
small or slowly progressing
This type of lesion leads to inflammation or necroses;
rapidly progressing
Which forms more reactionary dentin and why, young or old?
Young, more blood supply
3 defense reactions of pulp:
tubular sclerosis, tertiary reparative (osteo) dentin formation, pulp inflammation
When will reactionary dentin form after pulpal insult?
mild injury, primary odontoblasts survive
Appearance of reactionary dentin:
tubular pattern, resembles primary dentin
Tubular sclerosis:
process in which minerals deposited witiin the dentinal tubules, reducing the permeability to bacteria and toxic products
When is 3’ dentin formed:
response to various irritants, ie trauma or caries
Where is 3’ dentin formed?
dentin/pulp interface, area directly beneath stimulus
How does 3’ dentin provide extra protection to pulp?
by increasing the distance bw them and injurious stimuli
Direct pulp capping:
small pulpal exposure, sound surrounding dentin, dressed with appropriate biocompatible radiopaque base in contact w exposed pulp tissue prior to placing a final reso
Goals of direct pulp capping:
pulp vitality and function, normal response to electrical and thermal stimuli, formation of 2’/reparative dentin (check), no prolonged post-op pain or swelling, no pathological changes
indications of direct pulp capping:
easily controlled/light bleeding that can be stopped by cotton pellet, traumatic exposure in a dry, clean field, reported to dentist w/in 24h, small pin point exposure surrounded by sound dentin during mech prep of cavity
Contraindications for direct pulp capping:
systemic disease (diabetes, cancer), primary teeth w root resorption, pre-op tooth sensitivity, large pulp exposure, Rg changes, uncontrolled bleeding, non restorable tooth or restorable with low prognosis, tooth mobility, swelling and fistula
Direct capping px:
lidocaine, isolate, remove decay, pinpoint exposure then, control bleeding with saline, chlorhexidine, or HOO2, gently fry, CaOH2 directly on exposed pulp, GIC liner, restore w composite or amalgam, 6wk follow up
Inner “affected” dentin:
few bacteria, remineralizable, intermittently demineralized, vital, sensitive, can be left unexcavated (basis of indirect pulp capping)
Outer “infected” dentin:
bacterial invasion, unmineralizable, dead, wo sensation, highly demineralized, superficial layer, deteriorated collagen fibers, should be excavated
Goals of indirect pulp capping:
resto mat should seal involved dentin from OC, vitality of tooth preserved, no post-op pain and swelling, no 3’ o reparative dentin should be evident on RG after 6 to 12 wks, no evidence of internal resorption
Indications of indirect pulp capping:
minimal pulpal inflammation, complete removal of caries would lead to pulp exposure, mild pain assoc with eating, no spontaneous, extreme pain, no mobility, no PA radiolucency
Contraindications of indirect pulp capping:
pulpal or PA pathology, soft, leathery dentin covering all area of cavity, pain lingering after removal of stimulus, mobility, discoloration
Clinical px for indirect pulp capping:
lidocaine, isolation, cavity outline with high speed, remove superficial debris and most soft necrotic dentin (infected) w slow speed and round bur, caries dye, leave hard, leathery dentin, rinse with saline, gently air dry, CaOH2 cement on deepest position of prep, liner covered with GIC and final resto done (amal or comp), 6wk rg follow-up to check for reparative dentin formation
Multi-visit indirect pulp capping px:
after CaOH2 liner and cement, interim resto, after 6wk RG exam for reparative dentin formation, lidocaine, isolation, re-enter remove remaining caries, place final resto
6 pulp capping materials:
ZOE, CaOH2, MTA (mineral trioxide aggregate), glass ionomer, resin modified glass ionomer, adhesive systems
Props of ZOE cements:
germicidal, palliative, tight initial seal, arrest caries process
Affect of CaOH2 on bacteria:
initially bactericidal then static
Does CaOH2 stimulate reparative dentin?
yes
CaOH2, high or low toxicity?
low
Effect of CaOH2 on internal resorption:
stops it
Contraindications fr CaO2:
does not bond to tooth, degrades acid etching, not enough mech strength to withstand condensation pressure under amal resto, dissolves in oral “builds” (fluids?)
Indications for mineral trioxide aggregate:
adheres to tooth, stimulates reparative dentin better and faster than CaOH2, biocompatible, low cytotoxicity, better marginal seal, good mech strength, antibacterial
Contraindications for MTA:
gray color, 2 to 4 hr setting time, expensive, high solubility
Benefits of GIC:
better bacterial seal, fluoride release chem bond to tooth and resin cement
Props of adhesive systems:
complete marginal seal, prevents bacterial invasion, allows pulp repair
