Effects of various restorative and endodontic materials on dentin in detail along with developmental defects

1. CLINICAL
APPLICATIONS OF
DENTIN
Presented by : Dr Yashkumar Shah
Guided by : Dr Vijaykumar Shiraguppi

2. CONTENTS
• Pulp dentin complex
• Sodium hypochlorite
• Edta
• Chlorhexidene
• Calcium hydroxide
• Permeability
• Restorative dentistry

3. PULP DENTIN COMPLEX
Ancestry same but composition is
different
Function as a unit
Odontoblasts are cells of pulp
Processes extend into dentin
Stimulus to exposed dentin
Pulp also reacts

4. SODIUM HYPOCHLORITE

5. Concentration, volume, contact time, temperature
Organic components(collagen, non collagenous proteins)
Degradation--- fragmentation of long peptide chains
Reduce elastic modulus and flexural strength
Reduce the dentin microhardness
Exposure time– more penetration into the dentinal tubules
Bond strength to resin cements -- reduced

6. EDTA
Sequesters divalent and trivalent metal ions
After combination---- metal ions remain in solution but with diminished activity
Reacts- calcium ions in dentin– soluble chelates
Decalcifies– depth of 20-30µm – 5 mins
Decreased microhardness
Microhardness reduced in proportion to time for which it is applied
Bond strength to resin cements is reduced

7. CHLORHEXIDENE
Cationic- electrostatically binds to negatively charged surface– bacterial wall
permeable
Present in root canal dentin– longer periods
Bond strength to dentin remains stable
Resin infiltrated dentin – normal collagen network
Inhibits mmp which interferes with bonding

8. CALCIUM HYDROXIDE
Restorative material or intracanal medicament
Calcium and hydroxyl ions
Hydroxyl ions diffuse in the dentin more cervically then apically
High pH(12.5- 12.8)
Damages bacterial membrane by lipid peroxidation
Protein denaturation
Damage to DNA

9. Inconsistent to penetrate the dentinal tubules and eliminate organisms
Long term dressing(>30 days)--- risk of root fracture
Break link– hydroxyapatite and collagenous network
Neutralisation or denaturation of acid proteins and proteoglycans
Serve– bonding agent between collagen and hydroxyapaptite

10. Hard dentinal barrier
Absence of bacteria
Mild inflammatory response
Cogaulation necrosis
High Ph– neutralizes in deeper layers of pulp
Zone of liquifaction necrosis in superficial pulp
High pH--- antibacterial environment
Reparative dentin– not formed by calcium hydroxide

11. Success rates declined with follow ups
13%--- 95%
Variation in success rates
Microleakage leading to bacterial infiltration
89% of dentin bridges formed contain tunnel defects
Leaving voids for bacterial infiltration
Softens , dissolves, disintegrates over time.
Do not seal the pulp from external environment

13. DENTIN PERMEABILITY
More permeable Less permeable
Dentin near pulp horns Dentin further away
Axial walls of class 2 cavity Pulpal floor of class 2 cavity
Coronal dentin Root dentin
Normal dentin Sclerotic dentin

14. RESTORATIVE FACTORS
Effect of cavity preparation:
Frictional heat.
Desiccation.
Exposure of dentinal tubules.
Direct damage to odontoblast processes.
Factors associated with the restorative material and its placement:
Material toxicity
Insertion pressures
Thermal effects
Induced stresses
Effects subsequent to restoration:
Marginal leakage
Cuspal flexure

15. FRICTIONAL HEAT
Cavity preparation done under water spray
Pulpal damage repaired more rapidly
Severe pulpal necrosis at 5-17ºC increase in temperature
Approx 6ºC increase– 25sec of dry cutting– irreversible pulpal damage
Minimizes the increase of intrapulpal temperature
Low thermal diffusivity of dentin

16. DESSICATION
Direct damage to odontoblastic processes
Air to dry the cavity preparation
Outward fluid flow
Stimulus severe- displacement of odontoblastic cell bodies into tubules
0.5mm from pulp– no injury
0.3mm from pulp– direct odontoblast injury and death
Air cooled more damage
Water cooled faster recovery

17. EXPOSED TUBULES
Cutting limited to the affected dentin
Pulpal effects of restorative procedures would be minimal
Tubules occluded by mineral deposition
Less permeable to bacterial products and diffusible components of restorative
materials
More exposure, more permeability
More sensitivity and more leakage

18. PLACEMENT OF MATERIAL
Material toxicity
Effect of the material placement
Condensation pressure
Strain in the cusps
Pressure during crown cementation
Heat generated during polymerization of resin composites
Polymerization shrinkage
Permanent stresses in the tooth

19. EFFECTS AFTER RESTORATION
Microleakage under the restoration
Bacterial ingress
Microleakage or material toxicity?
Defective restoration
Secondary caries
Cavity preparation– increase– cuspal flexure– under
occlusal load
Cuspal flexure-clinical occlusal loads– upto 25µm–
marginal leakage

20. MATERIALS
Factors responsible for pulpal response to restorative material
Dentin
pretreatment
Permeability
of dentin
Age of
patient

21. ZINC OXIDE EUGENOL
Inhibitory concentrations higher than anti inflammatory
Direct contact– pulp– chronic inflammation– necrosis
Acid etched dentin– diffusion of eugenol– toxic to pulp
Bland or even therapeutic to pulp
Cytotoxic to all tissues without dentin barrier
Dose dependent effects

22. EFFECTS OF ZOE
HIGH DOSE(TOXIC) LOW DOSE(BENEFICIAL)
Induces cell death Inhibits white cell chemotaxis
Unknown vascular effects Inhibits prostaglandin synthesis
Inhibits cell growth and
respiration
Inhibits the nerve activity
ZOE placed in normal standard cavity depths
Response of pulp
Mild chronic inflammatory cell infiltration

23. ZINC PHOSPATE CEMENT
Irritating – low ph
Young tooth– more toxic old tooth– less toxic
Thin – more toxic thick– less toxic
Thermal conductivity– equal to that of enamel
Luting agent or base(for substitute to lost dentin)

24. Rodent pulp– induced vascular thrombosis and necrosis– low ph
Resolution of inflammation by 5-8 weeks
Set cement neutral– by 48 hours
Insulating materials for narrow RDT
Penetration of phosphoric acid into dentinal tubules and pulp

25. SILICATE CEMENTS
Rarely used nowadays
Cytotoxic and severe pulpal reactions
Ph– less than 3, less than 7 even after 7 months
Fluoride concentrations also inhibit cell growth
Standard depth cavities – acute inflammatory
response– disruption of odontoblastic layer

26. POLYCARBOXYLATE CEMENTS
Excellent biocompatibility with
the pulp
Equivalent to ZOE cements
Low ph (1.7) initially but rises
rapidly
Polyacrylic acid – large size–
limits the diffusion– dentinal
tubules
Not effective – dentin bridge
formation
Mild to moderate chronic
inflammation reported

27. COMPOSITES
Earlier, free monomer , detrimental to the pulp
Etching – minimal effect on pulp – 10-15 seconds
Polymerization shrinkage – problems to pulp
After curing– monomer is leached from composites
But managed by RDT

28. GLASS IONOMER CEMENTS
Set material– organic inorganic complex– high
molecular weight
Biocompatible
Chemical and mechanical bond
After 1 week, odontoblastic layer is disrupted
After 1 month pulp tissue recovers and
odontoblasts layer-- normal

29. REFERENCES
Textbook of Operative dentistry, Vimal Sikri, 9th edition
DAHL JE, ØRstavik DA. Responses of the pulp–dentin organ to dental restorative biomaterials.
Endodontic Topics. 2007 Sep;17(1):65-73.
Basrani B, Haapasalo M. Update on endodontic irrigating solutions. Endodontic topics. 2012
Sep;27(1):74-102.
SWIFT JR EJ, Trope M, Ritter AV. Vital pulp therapy for the mature tooth–can it work?. Endodontic
topics. 2003 Jul;5(1):49-56.
Song M, Yu B, Kim S, Hayashi M, Smith C, Sohn S, Kim E, Lim J, Stevenson RG, Kim RH. Clinical
and molecular perspectives of reparative dentin formation: Lessons learned from pulp-capping
materials and the emerging roles of calcium. Dental Clinics. 2017 Jan 1;61(1):93-110.