Reaction of the pulp to various capping materials 2003
Presented ByReham Mohamed Ali
Objectives of pulp treatmentTypes of Pulp TreatmentRequirements of pulp capping materiVarious capping materials and their r
Objectives of pulp treatmentMaintaining the integrity and health of the teeth and their supporting tissues.Maintaining the vitality of the exposed pulp or on a thin residual layer soft dentin.Pulp autolysis, however, can be stabilized, or pulp can be eliminated without compromising the function of the tooth.
-Different types of pulp ttt. have been recommended for primary teeth. They can be classified into two categories:Conservative Treatment (normal pulp or reversible pulpities)Protective Base(Indirect and direct) pulp capping PulpotomyRadical Treatment (irreversible pulpities or necrotic pulp)partial pulpectomyPulpectomy, and nonvital pulpotomy.
Requirements of pulp capping materialsIdeal dressing material for pulp therapy in primary teeth does not exist, but the material should be:BactericidalBiocompatibleHarmless to the pulp, surrounding structures and the permanent tooth germ.Promote healingNot interfere with physiologic process of resorption.
Reaction of the pulp tovarious capping materials (Indirect and Direct)
Zinc oxide-eugenolGermicidal agent Palliative affectUsed in indirect pulp capping due to its Excellent initial seal Kills bacteria present in This gives the pulp the chance for carious lesionshealing & regeneration So arrests the caries processDirect contact →chronic inflammatiom ,abscess formation and liquefaction necrosis.After 24H of capping →a mass of red blood cells &PNLs. Demarcated from the underlying tissue by zone of fibrin and inflammatory cells.After 2W of capping → pulp degeneration &chronic inflammation extends deep to the apex.
Calcium Hydroxide It presents two fundamental enzyme properties;- The inhibition of bacterial enzymes (antimicrobial effect).-Activation of tissue enzymes such as alkaline phosphatase (mineralizing effect). Calcium hydroxide (Ca(OH)2) encourages the formation of dentinal bridges. Used in direct pulp capping and pulpotomy procedures in permenant teeth. Due to its extreme alkalinity (pH of 12), -that frequently causes necrosis,-acute or chronic inflammation and -dystrophic calcification in the pulp tissue, it is not recommended for direct pulp cappingnor pulpotomies in primary dentition. Except in phase Ι.
Histological pictureThe calcified barrier is done as follow: Superficial necrosis. Deeply staining zone Area of fibrous tissue. Odontoblasts like cells.One month→ a calcified bridge appears in X-ray film.Next 12 m increase in thickness.Pulp beneath the calcified bridge remains vital & free from inflammation.
Antibiotics and corticosteriodsin combination with calcium hydroxide-These drugs were more successful in stimulating regular reparative dentine bridges than calcium hydroxide alone. However this work has not been expanded.Combination between tricalcium phosphate with calcium hydroxide-Produce maximum reparative dentine.
Adhesive LinersThere were suggested as direct pulp capping and pulpotomy agents with the introduction of adhesive dentistry in both primary and permanent dentition.Adhesive material forms- A complete marginal seal- Prevents bacterial intrusion- Allowed pulp repair, characterized by a new odontoblast cell layer underlying the dentin bridge formation.Many studies have indicated that composite & resin- modified glass-ionomer are compatible with pulp tissue.
The success of adhesive dentistry is dependent on etching the enamel and dentin. When phosphoric acid was used as an etching agent, in teeth with pulp exposures, it did not demonstrate pronounced inflammatory nor necrotic changes.Thin dentine bridges were seen in some of the extracted teethHowever Hebling et al. (1999), reported in their study that the (all bond 2) adhesive system did not appear to allow any pulp repair and does not appear to be indicated for pulp capping of human teeth.
Costa et al. (2003), evaluated the response of pulps of rats capped with resin-modified glass-ionomer cement or self- etching adhesive system. Despite some inflammatory pulpal response, both experimental pulp-capping agents allowed pulpal healing characterized by cell-rich fibro dentin and tertiary dentin deposition.
Mineral Trioxide Aggregate (MTA)Was approved for human usage by the FDA.MTA is a non-resorbable, ash-colored powder made primarily of fine hydrophilic particles of tricalcium aluminate, tricalcium silicate, silicate oxide, and tricalcium oxide.- Prevents microleakage over the vital pulp- Biocompatible- Promotes regeneration of the original tissues when it is placed in contact with the dental pulp or periradicular tissues.- MTA has the ability to stimulate cytokine release from bone cells promotes hard tissue formation.
Has numerous applications in dentistry. pulp capping pulpotomy root filling material fill wide open apices in immature teeth repair perforations and root fractures retrograde root filling material.Very effective in apexification compared to any other procedureIt is a technique-sensitive material. When the material is in contact with moisture it becomes a colloid gel, it sets in approximately 3-4 hours, and bismuth oxide has been added for radiopacity.
MTA has been used in pulp capping procedures and demonstrate remarkable success compared to calcium hydroxide.MTA pulpotomies consistently produced dentine bridge formation and maintained normal pulp histological appearance over 2- and 4-week observation periods. After 6 months pulpotomy with MTA resulted in the formation of calcified tissue that completely bridged the exposure site.The pulp C.T. presented characteristics of normality and a small segment of cells adhered to the mineralized mass.MTA showed clinical, radiographic and histologic success as a dressing material following pulpotomy in primary teeth compared to bioactive glass, ferric sulfate, and formocresol.
LaserDifferent studies were led on laser energyto overcome the histological deficits of electrosurgery.Used in Direct pulp capping & pulpotomy.Co2 Laser , Argon Laser, Diode Laser, Erbium:Yttrium-Aluminum Garnet (Er.YAG).Laser radiation has been proposed for pulp treatment based on its haemostatic, coagulative and sterilizing effects.
Advantagesexamination at 12 months demonstrated that teeth remained vital after using CO2 laser in direct pulp capping, corresponding to a success rate of 89%.Better clinical, radiographic, and histological results after using of laser for pulpotomy in primary teeth.Patient did not present any pain or discomfort and no analgesic was needed in Diode laser pulpotomies.DisadvantagesThe high cost.
Histological pictureLaser irradiation creates a superficial zone of coagulation necrosis that remains compatible with the underlying tissue and isolate pulp from effects of the subbase. Mortiz et al., reported that the thermal effects of laser radiation caused sterilization and scar formation in the irradiated area, which in turn preserves the pulp from bacterial invasion.Using CO2 laser on exposed pulps reported no histological damage to radicular pulp tissue.A study in (2001) demonstrated that YAG laser used in direct pulp capping had good healing capacity with dentin bridge formation.Argon laser pulpotomies in primary teeth reported that after sixty days, favorable responses of healing and repair in pulps.
Other Experimental Materials Growth factorsGrowth factors are biological modulators that are able to promote cell proliferation and differentiation.It is considered that the biological modulators will be the promising materials that will revive the expectations for regeneration of the exposed pulp tissue, rather than, devitalization.Osteogenic proteins, such as bone morphogenetic proteins (BMPs), which are protein bone extract containing multiple factors that stimulate bone formation.
Based on recent evidence that bone and dentin contain bone morphogenetic activity, the application of this growth factor (BMP) during pulpal healing has been proposed to induce reparative dentin formation.Other osteogenically active growth factors that have been identified arePDGF (platelet-derived growth factor),IGF (insulin-like growth factor) andFGF (fibroblast growth factor).TGF beta (transforming growth factor beta)
Histological pictureIt was observed that, the application of BMP on exposed pulp is dissolved within two weeks stimulates mitosis of the adjcent cells differentiate into osteodentinoblasts lay down osteodentin matrix differentiation of odontoblasts. were capable of inducing dentin formation.At two months the pulps were covered with tubular dentin at the pulp tissue side.
Studies in (2002), reported that implanted- bone sialoprotein (BSP) -bone morphogenic protein-7-and chondrogenic inducing agents (CIA)in amputated coronal pulp caused-formation of reparative dentin closing the pulpal wound (CIA),-or filled the mesial part of the coronal pulp (BSP),-or filled totally the pulp located in the root canal (BMP-7)However, further research is desired.
Calcium phosphate CompoundsAlpha-tricalcium phosphate & Tetracalcium phosphate (4CP) set & convert to hydroxyapatite.Stimulate the pulp to form hard tissue.No finding of necrotic pulp tissue in direct contact with 4CP cement compared to calcium hydroxide slight acidity after mixing4CP cement has mechanical strengths so it could be used as so called “dentin substitute”. Pulp capping agent lining material
(MBF) Modified Bioglass FormulaStanly et al. (2001) reported that MBF#68 used as direct pulp capping agent showed1- no evidence of mummification2- high incidence of properly positioned dentine bridge.Another study showed:At 2 weeks, inflammatory changes in the pulp. 4 weeks, some samples showed normal pulp histology, with evidence of vasodilation.
High molecular-weight hyaluronic acidIt can provide an environment suitable for reparative dentine formation through mesenchymal cell differentiation during healing of the amputated dental pulp.2 days after applicaton, wound surfaces were covered with blood and fibrin clots and inflammatory cells.At 1 week, differentiation of fibroblastic and odontoblast- like cells was observed beneath the wound layer: and odontoblast-like cells produced globular calcified nodules.At 2 weeks, a layer of reparative dentine had been.Between 30 and 60 days, the formation of reparative dentine had extended throughout the pulp chamber.
PropolisPropolis, a resinous material collected by honey bees, has been used as a traditional anti-infalmmatory and anti-bacterial medicine for many centuries.Used as indirect pulp capping paste when mixed with Zno powder and this showed similar effect of Zno and eugenol as secondry dentin formation. In direct capping with this paste showed no pulp degeneration and formation of protective layer.
Another study showed that direct pulp capping in rats with- Non-flavonoids Propolis at 1 w showed pulp inflammation, no dentine bridge formation a long the follow up period.- Flavonoids at 1w no evidence of inflammatory response.At 2 and 4w mild to moderate pulp inflammation was evident.In week 4 dentinal bridge formation was detected.
Reaction according to the pulpotomy TechniqueDevitalization:based on fixation (destroy) of the radicular pulp tissue “Formocresol, Electrosurgery and Laser”.Preservation:intended to only minimally insult the pulpal tissue, without initiating an inductive process. “Glutaraldehyde and Ferric Sulfate”Regeneration:Based on induction of reparative dentin formation by the pulp agent “Calcium Hydroxide , Adhesive Liners, MTA, portland cement, EMD and other experimental materials.
FormocresolThe most widely used dental medicamentin spite of the introduction of new capping materials.Introduced by Buckley in 1904, as a suppressant and mummifying agent.35% Cresol, 19% Formalin in a vehicle of glycerin and distilled water.1/5 dilution produces equivalent results as full strengthFormocresol acts by direct contact releasing formaldehyde which combines to cellular protein & fixes the pulp tissueFormocresol pulpoptomy technique was advocated by Sweet in the 1930, clinical and radiographic success rates of 98% have been reported.
Disadvantage:The International Agency for Research on Cancer (IARC) classified formaldehyde as carcinogenic to humans in June (2004). -causes nasopharyngeal cancers in humans -nasal & paranasal sinuses cancers -leukemia.Cause necrosis and sloughing If it touches the gingiva.Correlation between enamel defects in succedaneous teeth and formocresol pulpotomies performed on the primary dentition, such as -increase in the prevalence of hypoplastic and/or hypomineralization defects. -increased prevalence in positional alteration of the succedaneous teeth.This makes it very important for the profession to look for viable alternatives to Formocresol.
Histological pictureAfter exposure of pulp to formocresol for periods of 7 to 14 days three distinct zone become evident: Fixation of the pulp tissue adjacent to formocresol application sight (broad acidophilic zone) The middle third showed loss of cellular integrity which, alters the blood flow resulting in areas of ischemia (Atrophy). Middle to apical third showed an ingrowth of granulation tissue and broad zone of inflammatroy cells.In 2003, studies reported that fibrosis was more extensive at 4 weeks with evidence of calcification in certain samples.
ElectrosurgyConsidered as non-chemical devitalization of the pulp tissue.A technique in which the cutting effect performed without crushing of the tissue cells, hence minimal tissue destruction occur.
AdvantagesIt can be performed quicklyNo drugs involved that may produce undesirable systemic effects.No clinical and radiographical differences in the success rate between the electrosurgical and formocresol techniques.Contraindication:All general contraindication to surgeryWithin 15 feet of demand type cardiac pacemakersNear flammable anesthetic agentAround implantsIn irradiated pts..
Histological picturelayer of coagulation necrosis provides a barrier between healthy radicular tissue and the base material placed in the pulp chamber.fibrosis with acute and chronic inflammatory cells.Reparative dentin was detected four and six weeks post- treatment.No internal root resorption, periapical involvement was observed after four weeks.Many studies concluded that pulpotomized primary teeth treated by electrosurgery exhibited less histopathological reaction than treated by formocresol pulpotomy.
GlutaraldehydeAn excellent bactericidal agent and seems to offer some advantages compared with formocresol in the following ways:1.Formaldehyde reactions are reversible, gluteraldehyde reactions are not.2. Formald. is a small molecule, penetrates the apical foramen gluteraldehyde is a large molecule that does not.3. Formald. long reaction time, excess of solution to fix tissue, gluteraldehyde fixes tissue instantly, excess is unnecessary.
Histological pictureWhen placed over vital pulp tissue produces zone of superficial fixation that doesn’t migrate apically with very little underlying inflammation.The vitality of the remaining pulp is maintained.However the clinical success rates with glutaraldehyde have ranged widely, due to superficial fixation that may result in insufficient depth of antibacterial action causing a deep zone of chronic cell injury.It has also been observed that inadequate fixation leaves a deficient barrier to sub-base irritation, resulting in internal resorption.
Ferric SulfateFerric sulfate nonaldehyde agentcontrols hemorrhage without clot formation.Agglutinates blood protiens (produces hemostasis at pulp stumps by chemically sealing cut blood vessels).It is available in a 15.5% solution under the trade name of Astringedent.Advantageslow toxicity and no systemic side effects.Clinical and radiographical evaluation have reported favourable responses compared to those noted with formocresol and calcium hydroxide.
Histological picturePreventing clot formation might minimize the chances for chronic inflammation.However a study in 2004 showed that Ferric sulfate showed moderate inflammation of pulp with widespread necrosis in coronal pulp at 2 and 4 weeks.
The dental pulp is a highly vascular and innervated connective tissue, which is capable of healing by producing reparative dentin and/or dentin bridges in response to various stimuli and surgical exposure.The rationale for regeneration is the induction of reparative dentin formation by the pulpotomy agent.
( Portland cement (PCPC differs from MTA by the absence of bismuth ions and the presence of potassium ions.Both materials have comparable antibacterial activity and almost identical properties macroscopically, microscopically and by X-ray diffraction analysis.Similar clinical and radiographic effectiveness of PC and MTA as pulpotomy dressing agents.An inexpensive material.Save
PC and MTA have similar effect on pulpal cells and formation of dentin bridge when used for direct pulp capping or pulpotomy.Dentin bridge may be due to its mechanisms of action. Calcium oxide + water calcium hydroxideThe reaction of the Ca from calcium hydroxide with the carbon dioxide from the pulp tissue produces calcite crystals.Then, a rich extracellular network of fibronectin in close contact with these crystals can be observed (initiating step in the formation of a hard tissue barrier).Moreover, PC has an excellent sealing ability and fast setting, thus preventing the diffusion of the material into the tissues, and reducing microleakage during the pulp healing period.
Preoperative periapical radiograph of the mandibular 3-month follow-up periapical radiograph suggesting theleft primary molars of a 6-year old girl, which presented initial formation of a dentin bridge immediately belowextensive caries lesions and no signs of periapical lesion. the Portland cement in the distal root (arrow) of theAbsence of the mandibular left permanent second pulpotomized mandibular left second molar andpremolar was observed absence of periapical lesion in both pulpotomized mandibular left primary molars6-month follow-up periapical radiograph suggesting the 12-month follow-up periapical radiograph suggesting thepresence of the dentin bridge immediately below the initial radicular pulp obliterationPortland cement in the distal root (arrow) of thepulpotomized mandibular left second molar
HistologicallyAfter 120 days, the pulp wounds healed with hard tissue formation of considerable thickness.The coronary third of the root canals were completely closed by a newly formed homogeneous mineralized tissue.A basophilic-like mass constituting the remnants of the pulp capping materials could be seen covering the newly formed dentin.The pulp tissue was normal and free of inflammatory cells.No tissue necrosis was noticed.Presence of macrophages was also observed in some cases.
Enamel Matrix DerivativeEnamel matrix derivative (EMD), obtained from embryonic enamel of amelogenin.EMD commercially presented as EMDOGAIN® which has been successfully employed to incite natural cementogenesis to restore a fully functional periodontal ligament, cementum and alveolar bone in patients with advanced peridontitis.
After 6 months, using formocresol (FC) and (EMD) the clinical success rates for the FC and EMD groups was not statistically significant. However, the radiographic success rates for the FC and EMD groups showed a statistical significance between the two groups at 6 months.Periapical radiographs showing lower 2nd primary molars of the same patient treated with formocresol (figure1) and Emdogain® (figure2).(Figure 1): (Figure 2):At 6 months furcation radiolucency At 6 months no radiographic changesperiapical radiolucencyinternal resorption
The histopathological response of dental pulp tissue to EMD used in pulpotomized teeth showed that (2001,2003):-The pulp wound showed features of classic wound healing.-Subjacent to the healing wound, a bridge of new hard tissue (tertiary dentin) was formed, sealing off the wound from the healthy pulp tissue.-The pulp tissue subjacent to this new hard tissue was invariably free of all signs of inflammation. Moreover, a layer of odontoblast-like cells had formed, abutting the newly formed mineralized tissue.-Furthermore, it was also reported that growth of some bacteria including Streptococcus mutans, is inhibited by the presence of EMD.
-After twelve weeks, EMD demonstrated extensive amounts of hard tissue formed. Moreover, postoperative symptoms were less frequent.-These results offers preliminary evidence that EMD is a promising material which may be as successful, or more so, than other pulpotomy agents
Other Experimental Capping materialsEnriched Collagen Solution (ECS)Using of ECS as a Pulp Dressing in pulpotomies showed that:-80% of the ECS- treated teeth had vital pulps,-73% dentine bridges were present and-more than half of the ECS-treated teeth showed no pulpal inflammation after two months.
Freeze-Dried Bone (FDB) (Pediatric Dentistry.2004)-Histological findings of pulpotomized teeth using FDB showed histological findings very similar to calcium- hydroxide.-At 3 m Complete or partial calcific barrier was evident directly below treatment site.-Normal appearing odontoblastic cells were noted below the calcific barrier.-The apical third was vital with an occasional chronic inflammatory cell visible.
Ethyl-cyanoacrylatePresent adhesive, haemostatic and bacteriostatic properties.Induce more rapid tissue repair.Cyanoacrylate is an adhesive that results from the chemical reaction between formaldehyde and the esters of cyanoacetate.These products have been used in neurosurgery, gastrointestinal tract surgery and in oral and maxillofacial surgery.In dentistry, observation of a hard tissue barrier in monkey dental pulp covered with Isobutyl cyanoacrylate.
Teeth capped with ethyl-cyanoacrylate for 30 days showed:- Formation of a continuous hard tissue barrier at the level of pulpal amputation-These hard tissue barriers consisted of a bone-like layer at the surface and an underlying layer of dentin-like tissue.- No necrotic tissue between the barrier and the ethyl- cyanoacrylate.- The pulpal aspect, underneath the barrier, showed signs of vitality with the presence of a chronic inflammatory process. The inflammatory response was considered to be moderate in this area.- The other two-thirds of the pulpal tissue were free of inflammation.
OZONE• A gas containing three oxygen atoms per molecule. Ozone is a very powerful oxidizing agent and is formed when oxygen or air is subjected to electric discharge.The disinfection power of ozone makes the use of ozone in dentistry a very good alternative to standard antiseptics.Dissolved ozone in water and ozonated oils were and are still commonly used in different fields of dentistry. ozonated water can be used as a disinfectant and irrigant (HealOzone have the ability of pulp tissue dissolution in bovine teeth).
It is also postulated that ozone will penetrate through the apical foramen, and enter into the surrounding and supportive bone tissue. The effect of ozone on these tissues will be to encourage healing and regeneration (Bioregulator).With the development of a footpedal-activated dental handpiece with a suction feature, O3 gas can now be used safely in situations.
Stem cell deliveryA number of recent studies have demonstrated that stem cells, of both dental and non-dental origin, are capable of inducing odontogenesis and regenerating dentin.Deciduous teeth contain a population of more immature multipotent stem cells ("stem cells from human exfoliated deciduous teeth"; SHED), that are capable of forming dentin-like structures but not a complete dentin-pulp complex.A study in 2004, recommended that Ex vivo cell therapy may have an advantage, in that the cultured tissue stem/progenitor cells can be implanted after differentiation into odontoblasts and might result in copious amounts of reparative dentin formation.
Radical Treatment(irreversible pulpities or ( necrotic pulp
Calcium Hydroxide and iodoform(Vitapex, Diapex or Metapex)- There are Favorable reports about theirsuccessful use in infected primary teethPulpdentIn the year 2000 Mani et al. used calcium hydroxide paste in a methyl cellulose base as a root canal filling material in primary teeth of children.A success rate of 86.7 percent was reported . The authors suggested that the alkaline property of the material- helps in healing of periapical lesions by acting as a local buffer ,- activating the alkaline phosphates activity, which is important for hard tissue formation.
ConclusionFerric sulphate, MTA and Indirect pulp capping appear to be promising alternatives to formocresol pulpotomy for cariously exposed vital primary molars.Many investigators indicated that the healing of dental pulp exposures is not dependent on the pulp- capping material, but is related to the capacity of these materials to prevent bacterial leakage.
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