Vital Pulp Therapy PDF

Conservative Lec:8&9 Vital Pulp Therapy Vital pulp therapy is designed to preserve and maintain pulpal health in teeth that have been exposed to trauma, caries, restorative procedures, and anatomic anomalies. Vital pulp therapy (VPT) has been defined as treatment which aims at preserving and maintai...

Conservative Lec:8&9 Vital Pulp Therapy Vital pulp therapy is designed to preserve and maintain pulpal health in teeth that have been exposed to trauma, caries, restorative procedures, and anatomic anomalies. Vital pulp therapy (VPT) has been defined as treatment which aims at preserving and maintaining the pulp tissue that has been compromised but not destroyed by extensive dental caries, dental trauma, and restorative procedures or for iatrogenic reasons. Zhang and Yelick used another definition which added, “Stimulating the remaining pulp tissue to regenerate the dental pulp complex” to the previous definition INDICATIONS FOR VITAL PULP THERAPY Vital pulp therapy is recommended for all teeth diagnosed with reversible pulpitis or partially inflamed pulps in which the remaining healthy tissue can be conserved to generate a hard tissue barrier that seals and protects the pulp from future microbial insult. The initial diagnosis, based on radiographic evaluation, pulp testing, patient history and clinical evaluation, will determine the suitability and probable outcome for direct pulp capping and pulpotomy procedures. TECHNIQUES OF VITAL PULP THERAPY Direct Pulp Capping Direct pulp capping is defined as the “treatment of an exposed vital pulp by sealing the pulpal wound with a dental material placed directly on a mechanical or traumatic exposure to facilitate the formation of “reparative dentin” and maintenance of the vital pulp.”Pulp exposures, as a result of caries removal, tooth preparation, or trauma are all indications for direct pulp capping. However, pulp tissue jeopardized by acute inflammation, with longstanding exposure to oral microorganisms, may be an inappropriate candidate for direct pulp capping. Procedure: 1. Establish that the tooth is anesthetized and isolated with a rubber dam. 2. If pulp exposure occurs during caries removal disinfect the cavity with a chlorhexidine and gently rinse with anesthetic or sterile saline. 3. If any hemorrhage occurs, dab with a sterile cotton pellet until hemorrhage ceases. As noted previously, a sodium hypochlorite or chlorhexidine solution may be used to aid in hemostasis. 4. Apply a hard-setting calcium hydroxide liner directly to the exposure site. 5. Next, apply glass ionomer base/liner material to protect the calcium hydroxide dressing and to provide a better seal. 6. Finally, use a dentin/enamel bonding system to seal the cavity preparation and restore the tooth with an appropriate filling material. Treatment Considerations: Débridement: It is important to remove peripheral masses of carious dentin before beginning the excavation where an exposure may occur. This will prevent the pushing of infected dentin chips into the exposed pulp during the last stages of caries removal. When an exposure occurs, the area should be appropriately irrigated with nonirritating solutions such as normal saline to keep the pulp moist. Hemorrhage and Clotting: Hemorrhage at the exposure site can be controlled with cotton pellet pressure. A blood clot must not be allowed to form after the cessation of hemorrhage from the exposure site as it will impede pulpal healing. The capping material must directly contact pulp tissue to exert a reparative dentin bridge response. Bacterial Contamination: Studies emphasized the fact that bacterial microleakage under various restorations causes pulpal damage in deep lesions, not the toxic properties of the cavity liners and/or restorative materials. The success of pulp-capping procedures is dependent on prevention of microleakage by an adequate seal. Indirect Pulp Capping Indirect pulp capping is defined as “a procedure in which a material is placed on a thin partition of remaining carious dentin that, if removed, might expose the pulp in immature permanent teeth.”Non-symptomatic teeth with no radiographic evidence of pathosis show remarkable success using this technique, although it has been controversial for decades. Caries removal is completed using various techniques, to a perimeter near the tissue, without directly exposing the pulp. Selected teeth with deep carious lesions that receive conservative caries excavation, where direct pulp exposures were avoided, have demonstrated strong potential for repair since the primary odontoblasts are preserved. One or two-stage (step-wise) indirect pulp capping techniques are completed using either CH, zinc oxide-eugenol materials (ZOE) or CSCs. A major challenge with the clinical procedure (one or two-stage) is determining at what point the excavation is terminated. Other important considerations include the voids under the restorative material that form during the remineralization process, as the carious dentin desiccates and volume diminishes. Other complications can be the rapid reactivation of a dormant lesion or restoration failure. Procedures for Indirect Pulp Capping: Case selection based on clinical and radiographic assessment to substantiate the health of the pulp is critical for success. Only those teeth free from irreversible signs and symptoms should be considered for indirect pulp capping. Two-Appointment Technique (First Sitting) 1. Administer local anesthesia and isolate with a rubber dam. 2. Establish cavity outline with a high-speed hand-piece. 3. Remove the majority of soft, necrotic, infected dentin with a large round bur in a slow-speed hand-piece without exposing the pulp. 4. Remove peripheral carious dentin with sharp spoon excavators. Irrigate the cavity and dry with cotton pellets. 5. Cover the remaining affected dentin with a hard-set-ting calcium hydroxide dressing. 6. Fill or base the remainder of the cavity with a rein-forced ZOE cement (IRM) or a glass-ionomer cement to achieve a good seal. 7. Do not disturb this sealed cavity for 6 to 8 weeks. It may be necessary to use amalgam, composite resin, or a stainless steel crown as a final restoration to maintain this seal. Two-Appointment Technique (Second Sitting, 6 to 8 Weeks Later) If the tooth has been asymptomatic, the surrounding soft tissues are free from swelling, and the temporary filling is intact, the second step can be performed: 1. Bitewing radiographs of the treated tooth should be assessed for the presence of reparative dentin. 2. Again use local anesthesia and rubber dam isolation. 3. Carefully remove all temporary filling material, especially the calcium hydroxide dressing over the deep portions of the cavity floor. 4. The remaining affected carious dentin should appear dehydrated and “flaky” and should be easily removed. The area around the potential exposure should appear whitish and may be soft; this is “pre-dentin.” Do not disturb! 5. The cavity preparation should be irrigated and gently dried. 6. Cover the entire floor with hard-setting calcium hydroxide dressing. 7. A base should be placed with a reinforced ZOE or glass ionomer cement, and the tooth should receive a final restoration. One-Appointment Technique: The value of re-entry and re-excavation has been questioned by some clinicians when viewed in light of numerous studies reporting success rates of indirect pulp capping with calcium hydroxide ranging from 73 to 98%. On this basis, the need to uncover the residual dentin to remove dehydrated dentin and view the sclerotic changes has been questioned. The second entry subjects the pulp to potential risk of exposure owing to overzealous re-excavation. These investigators suggested that re-entry to remove the residual minimal carious dentin after capping with calcium hydroxide may not be necessary if the final restoration maintains a seal and the tooth is asymptomatic Partial Pulpotomy Partial pulpotomy (Cvek pulpotomy) is described as “the removal of a small portion of the vital coronal pulp as a means of preserving the remaining coronal and radicular pulp tissues.” Healthy coronal pulp tissue is, therefore, exposed after removing inflamed or necrotic tissue.51 Both direct pulp capping and partial pulpotomy are considered comparable procedures and differ only in the extent and volume of vital tissue remaining after treatment. Technique: Accomplish anesthesia, isolation, and surface disinfection. At the exposure site, remove 1–2 mm of the superficial pulp tissue using a sharp, sterile diamond rotary instrument. The diamond should be running at very high speed with copious water spray. If excessive bleeding continues, extend the preparation apically. Rinse the area with sterile saline, anesthetic solution, sodium hypochlorite or chlorhexidine to facilitate hemostasis and dry with a sterile cotton pellet. Take care to avoid formation of a blood clot, which compromises the prognosis. If the pulp is large enough to allow an additional 1–2 mm loss of tissue through necrosis, mix and apply a thin layer of pure calcium hydroxide. If the pulp is not large enough to accommodate any further loss of tissue, mix and apply a hard-setting calcium hydroxide liner such as Dycal. This will not cause tissue necrosis in the same manner as pure calcium hydroxide. As in teeth with conventional direct pulp caps, place a glass-ionomer liner or base, a dentin/ enamel adhesive and restorative material. Pulpotomy Pulpotomy is a more invasive procedure defined as “the removal of the coronal portion of a vital pulp as a means of preserving the vitality of the remaining radicular portion. It may be performed as an emergency procedure for temporary relief of symptoms or therapeutic measure. The entire coronal pulp is removed to the level of the pulpal floor, or cementoenamel junction, and a capping material is placed over the canal orifices, or remaining radicular tissue. Although studies indicate that short-term success rates are favorable, this procedure is generally recommended for deciduous rather than permanent teeth. Technique: The technique for a full pulpotomy is similar to that of the partial pulpotomy, except that the entire mass of coronal pulp tissue is removed, normally to the canal orifices, but as much as 2–3 mm apical to the orifices. The tissue is capped with calcium hydroxide in a manner similar to partial pulpotomy. MATERIALS FOR VITAL PULP THERAPY The search for the ideal vital pulp therapy material has led researchers to investigate many different materials. These include Ca(OH)2 compounds, zinc oxide, calcium phosphate, zinc phosphate and polycarboxylate cements, calciumtetracycline chelate, antibiotic and growth factor combinations, calcium phosphate ceramics, Emdogain, Bioglass, cyanoacrylate, hydrophilic resins, hydroxyapatite, resin-modified glass ionomers, and, recently, MTA and biodentin and many other bioceramics.. Other studies have included Ledermix, glycerrhetinic acid-antibiotic mix, potassium nitrate, and dimethyl isosorbide. Innovative methods have also been used to eliminate caries progression and stimulate the repair of affected pulpal tissue and include ozone technology, lasers, and bioactive agents that activate pulpal defenses. Researchers have strived for decades to identify and produce a pulp capping material that, ideally, would exhibit the following characteristics: Stimulate reparative dentin formation Maintain pulpal vitality Release fluoride to prevent secondary caries Bactericidal or bacteriostatic Adhere to dentin Adhere to restorative material Resist forces during restoration placement Must resist forces under restoration during lifetime of restoration Sterile Radiopaque Provide bacterial seal Calcium hydroxide: This material, long considered the "benchmark" for vital pulp therapy materials has been shown to have some desirable properties, but long-term study outcomes have been variable. Beneficial characteristics include a bactericidal component owing to its high alkaline pH and the irritation of pulp tissue that stimulates pulpal defense and repair. Conversely, Ca(OH)2 has been shown to be cytotoxic in cell cultures, does not exclusively stimulate reparative dentin formation, shows poor marginal adaptation to dentin, and induces pulp cell apoptosis. The material can be associated with primary tooth resorption, it can degrade and dissolve beneath restorations, and it can also suffer interfacial failure upon amalgam condensation. It produces a gap between the dentin interface when used with bonding resins. Dentin bridges beneath Ca(OH)2 are associated with tunnel defects, and the material fails to provide a long-term seal against microleakage when used as a pulp capping agent. The disintegration of Ca(OH)2 under restorations associated with defects in the dentinal bridge can provide microorganisms with a pathway for penetration into pulpal tissue and the subsequent stimulation of circulating immune cells, inducing pulpal irritation and potential pulpal calcification and canal obliteration. Resin-modified glass ionomers: Resin-modified glass ionomers have been successful as indirect pulp capping agent even in cavities with minimal remaining dentin thickness. This may be due to their capacity to bond to the dentin and their antimicrobial effect. Contrary to these useful properties, poor responses have been reported in direct pulp capping of human teeth with RMGIs. The teeth exhibited moderate to intense inflammatory responses including large necrotic zone and lack of dentin bridge formation. Thus the application of RMGIs directly on the pulp tissue is not recommended. Adhesive resins: Recently available self-etching adhesive systems as pulp capping material resulted in unresolved inflammatory responses and minimal pulp tissue repair. Many of the resin components in dentin adhesives are vasorelaxant and promote bleeding after hemostasis has been achieved with hemostatic agents. Furthermore, the presence of resin particles observed in the pulp seemed to be a trigger in stimulating the inflammation and foreign body reaction which results in the lack of reparative bridge formation. Research by several investigators in humans showed that these pulp capping materials do not allow for predictable pulpal healing, nor do they provide a favorable environment for reparative dentin formation and the exclusion of microorganisms. Mineral trioxide aggregate (MTA): MTA was introduced to endodontics by Lee et al. in the early 1990s. This bioactive silicate cement was originally composed of tricalcium silicate, tricalcium aluminate, tricalcium oxide, silicate oxide, and other mineral oxides. The cement exhibits many favorable characteristics, which make it a superior material when used as a direct pulp capping material in adult teeth or as an agent in partial or complete pulpotomy in primary teeth. MTA can be set in the presence of blood and moisture. It exhibits a superior marginal adaptation and is non-absorbable, and when it cures in the presence of calcium ions and tissue fluids, it forms a reactionary layer at the dentin interface resembling hydroxyapatite in structure. Other biocompatible characteristics include a sustained alkaline pH after curing, small particle size, and a slow release of calcium ions. Studies have also demonstrated that MTA stimulates cytokine release, induces pulpal cell proliferation, and promotes hard tissue formation. The high alkalinity of MTA and its calcium release and sustained pH at 12.5 is most likely responsible for preventing any further microbial growth of residual microorganisms left after caries excavation. The high pH also extracts growth factors from adjacent dentin thought to be responsible for promoting dentinal bridging. Bioceramics: Recently, Endosequence Root Repair Material (ERRM), BioAggretate, Biodentin and many other bioceramic-based products have been introduced which can be used with same applications as MTA. Biodentine™ consists of a powder in a capsule and liquid in a pipette. The powder mainly contains tricalcium and dicalcium silicate - the principal component of Portland cement - as well as calcium carbonate. Zirconium dioxide serves as contrast medium. The liquid consists of calcium chloride in aqueous solution with an admixture of polycarboxylate. The powder is mixed with the liquid in a capsule in the triturator for 30 seconds. Once mixed, Biodentine™ sets in approximately 12 minutes. Calcium hydroxide is formed during the setting of the cement. The consistency of Biodentine™ is similar to that of phosphate cement. TheraCal LC TheraCal LC is a light-cured, resin-modified calcium silicate material. It is indicated for direct and indirect pulp capping. The formulation consists of tricalcium silicate particles in a hydrophilic monomer that stimulates hydroxyapatite and secondary dentin bridge formation through calcium release and an alkaline pH. CO2 Laser: Recently CO2 laser has been shown a good success rate in pulp capping. One study shown that the success rate of 89% in the laser group is higher than that obtained from the conventional pulp capping technique. The most important effects of laser irradiation seem to be sterilization and scar formation in the irradiation area due to the thermal effect, which may help to preserve the pulp from bacterial invasion. Another effect of laser treatment might be direct stimulation of dentin formation as indicated by one study using super pulsed CO2 laser instead of the continuous wave to prevent significant temperature rises at the pulp tissue.