15.ppt
TRANSCRIPT
INTRODUCTION:
During the last 200yrs there have been many changes in the
rationale governing the treatment of dental pulp.
Question concerning which technique gives the highest % of
success. It is essential to have thorough understandings of the
compatibility of the material, its physiological response, and the
histological changes that takes place during and after the use of
medicaments
HISTORY
Mid – 18th century - Pierre Fauchard
Mid – 19th century - John Tomes
“ Layer of discolored dentin” (indirect)
1756 – Philip Ptaff – “golf leaf” (direct pulp capping)
1850 – ‘Principles of indirect pulp capping – Foster
1860 – Taft – ‘mixture of sorghum molasses/sparrow
1866 – Atkinson - Creosote
1891 – W.D. Miller – Antiseptics
1930 – Teucner – New era
1980 – Calcium phosphate cement
1990 – Dentin bonding agent
1993 – Mineral trioxide aggregate
Zones of early enamel caries:
I Translucent: More porous (1% pore volume/0.1% normal enamel)
1.2% mineral loss
II Dark zone: Positive – more porous (2-4%) – 6% mineral loss
III Body of lesion: 5% in periphery & 25% center – 25% mineral loss
IV: Surface zone: Unaffected (20-100µm) – 10% mineral loss
Zones of dentinal caries:
I Normal dentin: No bacteria
II Sub-transparent dentin: Demineralization of intertubular – crystals
– odontoblastic process are damaged
III Transparent dentin: Softer
IV Turbid dentin: Bacterial invasion – widening & destruction of
tubules– little mineral – denatured collagen
V Infected dentin: Decomposed dentin
Infected dentin Affected dentin
Highly deminerlized Less
Unremineralizable Remineralizable
Superficial layer Deeper
Lacking sensation Sensitive
Can be stained Does not stain
Should be excavated Left behind
DIRECT PULP CAPPING
Application of a medicament to exposed pulp to preserve the vitality
1. Pinpoint – sound dentin – no hemorrhage - mild infl. – repaired
2. Pinpoint – sound dentin – drop of blood – mild infl.
3. Infected dentin – considerable – site far – doubtful
4. Profuse – greater infl. – very doubtful
5. Infl. Pus/fluid – destruction – not indicated
Indications: No H/O pain.
Exposure size < 4 mm
No observable hemorrhage
Clean uncontaminated field
Dentin at periphery is repairable
No pathologic changes
Contraindications: Severe toothache
Tooth mobility
Excess hemorrhage
Purulent discharge
Radiographic changes
Direct Pulp Capping
INDIRECT PULP CAPPING
Gross caries is removed and the cavity is sealed with a biocompatible material
Indication: Pulp inflammation is minimal – complete removal of caries would cause an exposure
Contraindication: Severe toothache
Tooth mobility
Purulent discharge
Radiographic changes
Indirect Pulp Capping
Objectives: Seal completely
Vitality.
No prolonged post-treatment
Pulp healing & tertiary dentin
No pathological changes.
Failures:
Degree of trauma
Sealing pressure
Low threshold of host resistance
Presence of microorganisms
Failure of an aseptic technique
Ivory Quill Gold-beaters skin Oiled skin
Paper Plaster of paris Canada balsam Asbestos Gutta percha
Lactophosphate of lime Oxychloride Oxyphosphate Oxyxulphate of zinc cement
Calcium hydroxide Pulp Caps – Celluloid Dome
Zinc phosphate
Zinc oxide eugenol
Zinc polycarboxylate
Glass ionomer
Calcium phosphate Freezed dried bone MTA
Bone cement
Demineralized dentin matrix Bioactive glass
Dentin chips Collagen matrix
Zinc phosphate cement
– Most irritating (acidity / exothermic)
- Solubility (0.06%), pH 3.5 (neutral)
ED >2.5 mm – Healthy reparative, but occ. unhealthy
ED 1.5 - 2.5 mm – Unhealthy reparative, sometimes destruction
ED <1.5 mm – destruction of pulp tissue
Zinc oxide eugenol:- Least irritating (eugenol / impurities)- Solubility (0.4%), pH 6.6-8- Obtudent (sedative)
1. Pulp is healthy, site is controlled microbially & reparable
Limited Propagate Firbosis Acute infl.
Fibrous tissue Pulp/root canal No bridge Necrosis
Matrix formation Necrosis (slow/symptomless)
Mineralization
Bridging
2. Acute inflammation – bridging is unlikely to occur
3. Dentin chips – fibrous – bridging. (nucleation)
4. Impingement (force, thin matrix) – interfere healing.
Zinc polycarboxylate
- minimally irritant
- Solubility (0.6%), pH 3-4 (5-6)
ED >1mm = healthy reparative dentin
ED <1mm = Unhealthy / frequently destruction
BORISSOV 2003 – 5% potassium nitrate (anti-inflammatory effect of
alkaline medium) – reparative dentin.
Glass ionomer cement
- irritant
ED > 1.5 mm = healthy dentin
ED 0.5 – 1 mm = unhealthy dentin
ED < 0.5 mm = destruction
Cyanoacrylate cements
- Composite-type polymers
- methyl, ethyl, n-butyl or isobutyl cyanoacrylate
Rapid hemostasis, biocompatible & reparative dentin
formation – without necrotic zone. (Berkman & Bhasker et al, 1971)
On degradation – low-grade degeneration – cellular layer – chemical
equilibrium – attract calcium - mineralization
Spray form
Fine drop of liquid
Additive in capping material:
Diff. Substance – to reduce infl./eliminate infection
Corticosteriods: Degenerative changes – interfere hard tissue
(Hansen, 1963, Everett 1969, Barker 1969, Mitchell 1970,
Soto-Feine 1982)
Antibiotics: Little information on topical application (cytotoxic/hypersensitivity)
[Tetracycline, neomycin, penicillin, vancomycin – Obersztyn 1968, Baker 1969, Gardner 1971, Page 1973, Bergenholtz
1977]
Antiseptics: Cytotoxcity
(Dankert 1976, Martin 1978, Kopel 1980, Cunningham 1982)
Calcium Hydroxide
In 1920, Herman- irritant (alkalinity)- Solubility (0.4-7.8%), pH 9.2-11.7
ED > 1mm = healthy reparative dentinED < 1mm = unhealthy reparative dentin
Direct Contact1. Zone of obliteration (compressed tissue) –
debris, dentinal fragment, hemorrhage, blood clots, Ca(OH).2. Zone of edema3. Zone of coagulative necrosis(mummifying) -
24-hours
2-3 weeks
4-5 weeks
2-months
Ca(OH)2
Ca2+ OH-
Reduced capillary permeability Neutralize acid -osteoblast
Reduced serum flow Pyrophosphates activity (pH)
Reduced – level of inhibitory Increased Ca2+ dependent pyrophosphate pyrophosphate
Uncontrolled mineralization
Advantages:
Bactericidal & bacteriostatic
Promote healing & repair
pH – fibroblasts
Inexpensive and easy to use
Disadvantages:
Does not exclusively – dentinogenesis/reparative dentin
Degrade during acid etching
Do not adhere to dentin / resin restoration
Solubility
Settable calcium hydroxide:
Dycal
Hydrex
Reolit
Life
Nu-Cap
Dycal VLC
Reocap
Procal
Water-Based Calcium Hydroxide • Direct pulp-capping • Radiopaque •63% Ca(oH)2•"Save cap"
Self-Curing Calcium Hydroxide • Indirect pulp capping• 25 % Ca(oH)2
Light-Curing Calcium Hydroxide • Cures in 30 seconds • Compressive strength (135 MPa)
COX et al – capacity of the capping agents to provide a biologic
seal against immediate & long-term bacterial microleakage along
the entire tooth surface
Hybridization of dentin
Superior ability to adhere to both demineralized enamel and dentin
Inoue et al, 1992 – excellent pulp healing
Katoh et al, 1993 – good healing with adhesive resin
Miyakoshi et al, 1994 – protective layer on the pulpal surface
Jontell et al, 1995 – immunosuppression -pulpal immunocompetent cells
Tsuneda et al, 1995 – histopathologic – best healing(absence infl.)
Mijakoshi et al – 4-META-MMB-TBB – effective biological seal
Ability to seal the exposure site from bacterial microleakage
• Cytotoxic – pulpal inflammation
• Leachable nonpolymerized monomers
• Accumulation of DBA fragments
In vitro/ In vivo – components are cytotoxic to pulp cells (fibroblast)
Current adhesives (SEP) – suitable property – lack of diffusion of resin
globules (DT) – may be useful and safe
While bonding system have greatly improved sealing
ability in recent years, there is a clear evidence that even with the
best bonding system, there is microleakage of bacteria around the
restoration
Need long-term clinical performance
MTYA1-Ca (resinous agent)
Powder: Microfiller 89%
Calcium hydroxide 10%
Benzyl peroxide (catalyst) 1%BPO
Liquid: Triethylene glycol dimethacrylate 67.5%(3G)
Glyceryl methacrylate 30%GM
Methacryloyl tyrosine amide(MTYA) – adhesive
Dimethyaminoethylmethacrylate (initiator) DMAEMA
Camphoroqiunone ( catalyst)
• Powder:Liquid = 3:5
• MTYA – good adhesion (adhesive monomer)
• Triethylene glycol dimethacrylate – Mechanical prop
• Glyceryl methacrylate – bond strength
MTYA1-Ca – good physicalproperties.
Potential to be used as a direct pulp capping agent
Niinuma et al,1999
Calcium phosphate cements (1980)Ca:P
Octacalcium phosphate, (Ca4H(PO4)3)3H2O 1.33
Tricalcium phosphate, (Ca3(PO4)2) 1.50
Calcium hydroxyapatite, (Ca5(OH)(PO4)3) 1.67
Dicalcium phosphate dihydrate, (CaHPO4 2H2O) 1.0
Nucleation/growth – amorphous
solid – crystalline HAP
Further investigations – explain
how exactly – contribute RD formations
Bioactive glass
Calcium 24.5%Sodium 24.5%
Silica 45.0%
Phosphorus 6.0%
Grainy particles Porous
Negative charge, - attract building blocks
Framework of hydroxy-carbonate-apatite crystals - trapping & bonding building blocks
Amorphous non-crystalline – ionic release
MTA
Fine hydrophilic particles – Tricalcium silicate
- Tricalcium aluminate
- Tricalcium oxide
- Silicate oxide
Hydration – colloidal gel - < 4 hours – pH 10.2
to 12.5
• Resistant to marginal leakage
• Allows normal healing response
• Set in the presence of moisture
• Reduces bacterial migration
• Open a single pouch
• Mix with the water ampule (sterile water) provided to a creamy consistency
• Condense with a condenser
•Approximately 5 - 15 minutes' working time and 4 - 6 hours' setting time
•Action: Stimulate cytokine release – hard tissue
formation
Dentinogenesis – sealing ability, biocompatibility & alkalinity
Portland Cement
• Ingredients in common with MTA, (calcium phosphate, calcium oxide, & silica.)
• MTA - bismuth oxide (radiopacity), - absent PC
• Induce dentin bridge - excellent sealing, fast ST 5 minutes.
BONE CEMENT
Powder - (polymethyl) methacrylate polymer, methyl methacrylate – styrene copolymer & barium sulphate
Liquid - methylmethacrylate monomer.
Antibiotics - 2% weight by weight (gentamicin sulphate)
Advantage: Moist environment.
Gary Mathew Holt & Thom C Dumsha - dye leakage
In vitro bacteriological study by High et al - bacteriocidal
An ideal repair material is one that will support osteogenesis and
cementogenesis and biocompatible, non toxic, non carcinogenic, easily
obtainable, convenient to use, biodegradable. No such “ideal material”
has yet been identified
LASER
First laser use in endodontics – Weichman & Johnson, 1971• CO2• Argon• Nd YAG• Er. YAG
Immense heat & power – sterilizes scar formation – preserve
pulp from bacterial invasion
Blood extravasation – gradual organization – hard tissue formation
Melcer et al, 1987 – exposed pulp tissue (CO2) – hemostasis
Ebihara et al, 1992 – Nd:YAG – 89% success
Moritz et al, 1998 – CO2 – direct pulp capping
Sekine et al – No reparative dentin formation (28 days)
Wigdor et al – No reparative dentin – after 4 days (CO2 laser)
Tankano et al - Reparative dentin (Er.YAG)
With the development of thinner, more flexible and durable
laser fibers, laser application in endodontics will increase, but
acceptance of this technology by clinicians has remained limited
Two concepts
Mechanical concepts Biological properties
Disappearing Bioactive molecules
Bioactive molecules: Materials that induce a specific biological activity in the body
With the development of tissue engineering, a new era that will
lead to modifications in daily practice in the near future
Bioengineered reconstruction, regeneration – four components
Undifferentiated / STEM cells
- repair site – cells prog. specifically – tissue
3D-ECM
- Specific – possess intrinsic mineralizing prop
Signaling molecules
- cytokines, growth factors, hormones
Carrier
- important factor, scaffold
DSPP
DPP DSP
- nucleator for mineralization
- dentin mineralization
• Dentin matrix protein (DMP-1)
• Bone sialoprotein –I (osteopontin) Bone sialoprotein
• Bone sialoprotein –II
TGF-ß
BMP-7 / OP1
IGF – I & II
Rutherford et al - hOP-1/ bovine type-1 collagen, sterile saline, reparative dentine
Nakashima - BMP-2 & BMP–4 - dentin formation
Hu et al - (i.e.EGF, FGF, IGFII, PDGF-BB, and TGF-ß) - TGF-ß1 = enhanced reparative dentin
Six et al - the effect of dose-dependent BMP-7 - collagen pellets containing 1, 3 or 10 µg = No difference
BMP-7/OP-1
Enamel matrix (EMD) induces hard tissue formation in the pulp and that it may be a suitable capping agent.
Emdogain®Gel consists of EMD in propylene glycol alginate.
Two vials - a vehicle solution and freeze dried enamel matrix
proteins (amelogenin fraction). When mixed,
they create a viscous,
easy to use,
syringable gel
Treatment of dentine matrix with various cavity conditioning
agents -solubilize TGF-b1
EDTA was the most effective agent
Calcium hydroxide is also able to solubilise TGFb-1 from dentine matrix
Questions concerning the application of these biological modulators:
1. Development & classification of biological modulators.
2. Interaction - artificial barriers, biological modulators, & restorative
materials.
3. Effects - status (i.e. normal, inflamed or infected). Most of the
research - vital, non-inflamed
4. The effect of aging on pulpal response.
5. The delivery vehicle used for the molecules.
6. The dose response effects of the molecules.
7. The half-life of the molecules.
8. Immunological problems due to repeated implantation
Reparative Dentin Formation by Ultrasound-Mediated Gene Delivery of Growth/Differentiation Factor 11
BMPs - Odontogenic differentiation.
Gene therapy - induce reparative dentin. Gene transfer
(Gdf11)/Bmp11 plasmid DNA into dental pulp stem cells by
sonoporation & stimulated by ultrasound (1 MHz, 0.5 W/cm2, 30 sec) -
stimulated a large amount of reparative dentin formation on the
amputated dental pulp in canine teeth in vivo.
Gdf11 cDNA plasmid - by sonoporation in vitro, induced Dsp
(marker for odontoblasts.)
Thus, the result suggested the possible use of BMP using
ultrasound-mediated gene therapy for endodontic treatment.
• Endodontic & restorative challenge
• Debridement & obturation - impossible
APEXIFICATION
Process of creating an environment with in the root canal & periapical tissue after pulp death that allows a calcified barrier to form across the open apex.
Indication: Immature tooth with pulp necrosis.
Contraindication: - Root #
- Replacement resorption
- Very short roots.
Objective: Calcified barrier / artificial barrier
• Nygaard-Ostby – Lacerate the apical tissue – cementum-like tissue
Elimination of residues/bacteria – stimulate the radicular formation – not necessary – chemical stimulator – cementum
• Baouchon et al – Walkoff’paste
• Kaiser at al – Calcium hydroxide (1956)
• Frank - Published
MATERIALS
Ca(OH)2
MTA
Tricalcium Phosphate
TECHNIQUE:
Anesthesia and Rubber Dam Isolation
Bigger Access Cavity
EWL
Hypochlorite
Ultrasonic Devices Recommended
Ca(OH)2
Permanent filling
4-6 week, 3rd, 6th,& 24 month recall
• Duration of treatment
• Marginal adaptability
• Sealing ability
1. Good sealing ability2. Marginal adaptation3. Biocompatible4. Used in moisture presence5. Speed of completion of therapy
One Visit Apexification
MTA Angelus
Composition
SiO2, K2O, Al2O3, Na2O, Fe2O3, SO3, CaO, Bi2O3, MgO and insoluble residues of CaO, KSO4, NaSO4 and crystalline silica.
ST - Gel - in 10 -15 minutes.
Success: Absence of signs / symptoms
Calcified barrier
Failure: Bacterial contamination (seal / debridement)
Infected necrotic material
Undetected root #
Conclusion:
The last decade has proved to be an exciting time for pulp
biology & has led to rapid advances in repair of this tissue. At the start
of a new millennium, the use of biological molecules for the
development of novel treatment modalities is in sight.
These approaches have potential applications in unexposed as
well as in exposed pulp situations for the restoration of the structural
integrity of the dentin wall by reparative dentinogenesis