Calcium Hydroxide and Chlorhexidine as root canal irrigants

The mechanical instrumentation must be augmented  with antimicrobial irrigant.  Sodium hypochlorite - similar to Clorox Bleach - is almost universally the irrigant of choice in root canal treatment, and has been for many, many years.  Various  strengths of it are used but the research  shows a wide range of  helpful dilutions with not much difference in effect.  It is very helpful for a couple of reasons.  First it is highly antimicrobial for the vast majority of bacteria, viruses, spores, fungi and protozoa found in root canals. Secondly it chemically  helps to actually "dissolve" remaining bits of tissue that could not be removed with the  metal instruments.   It is  the only irrigant that can disrupt and remove  microbial biofilm from the infected  root canal system.  Research, however, has shown that Sodium hypochlorite, while almost universally depended on, will not completely kill all the bacteria in the tooth in up to at least  50% of cases studied.   Research over many, many years has shown that the addition  of Calcium hydroxide as a medication inside the canal significantly further reduced bacteria.
Other medications commonly used like CMCP or phenol only succeeded in about 66% of cases.  Other research using Calcium Hydroxide, but  for  SHORTER periods of  time, like one or two weeks, showed no significant improved effectiveness over the CMCP or Phenol.  It seems very important to me to leave the Calcium Hydroxide in the canals for at least 4 weeks for maximum effectiveness.
While Calcium Hydroxide does many wonderful things, it has been found to lack in one area.  There are two microbes important in root canal treatment that it does not kill:     Candida and E- faecalis.  When root canal treatment fails as it sometimes does, very often E faecalis is found in the re-infected canals and it is often thought to be responsible for the failure.  Fortunately, chlorhexidine has been found to be very  effective against it.  
Mixtures of chlorhexidine and Calcium Hydroxide have been shown to have additive benefit against Candida and E- faecalis. That is, the mixture is  more effective than either one alone. It's effective in reducing discomfort and promoting good healing.
Chlorhexidine, which  is seen or used in the form of "Peridex", a prescription mouth rinse for periodontal problems, can be used along with Sodium hypochlorite as a canal irrigant. It  is safe and innocuous except to the  germs that  reside in the mouth and root canals!

Sodium Hypochlorite as an root canal Irrigant

Sodium hypochlorite (NaOCl) in various concentrations is the most widely used

endodontic irrigant, but it can be an irritant to vital tissues. There are several

reports about the complications of irrigation with NaOCl during root canal therapy.

Most of the complications are the result of accidental extrusion of the solution from

the apical foramen or accessory canals or perforations into the periapical area. This

article is a review and comparison of all reported NaOCl accidents in the literature.

The impetus behind root canal cleaning and shaping is the elimination of tissue remnants,

bacteria, and toxins from the root canal system. This is generally accepted to be a major

factor in the success of root canal treatment. Mechanical procedures alone are insufficient

for total canal cleaning. Residual pulpal tissue, bacteria, and dentin debris may persist in

the irregularities of canal systems. Therefore, irrigating solutions should support and

complement endodontic preparation. These irrigants should flush out dentin debris,

dissolve organic tissue, disinfect the canal system, and provide lubrication during

instrumentation, without irritating the surrounding tissues. Some of the irrigants currently

used include hydrogen peroxide, physiologic saline, water, sodium hypochlorite (NaOCl),

chlorhexidine, and electrochemically activated water.

Because of its physicochemical and antibacterial properties, NaOCl is one of the most

popular irrigants.It is an inexpensive, readily available, and easily used chemical that usually rates well in

research.

A variety of NaOCl concentrations ranging from 0.5% to 5.25% have been advocated, as

well as a variety of temperatures. The longer the solution can remain in contact with

tissue, the higher the temperature of the solution, and the higher the concentration, the

greater the ability of NaOCl to dissolve the tissue.The optimum concentration for use

clinically is still a matter of controversy. Consequently, the clinician must decide on the

concentration and temperature of the NaOCl and the potential consequences of this

choice.

Advantages of NaOCl

The ability of NaOCl to dissolve organic soft tissue of the pulp and predentin is a result

of oxidation. The powerful oxidative activity of hypochlorite not only dissolves the

pulpal and dentinal tissue but also acts as a potent antimicrobial agent. It is well

recognized to be effective against a broad range of pathogens: gram-positive and gramnegative

bacteria, fungi, spores, and viruses including the human immunodeficiency

virus.

NaOCl, especially when used in high concentrations, is known to be effective in

dissolving organic tissue remnants and disinfecting the canal system.Effective

concentrations of NaOCl range from 2.6% o 5.25%. The dilution of NaOCl was

suggested because it has been proved that concentrations over 0.5% are cytotoxic.

Compared with a chlorhexidine gel, NaOCl not only has a higher capacity to kill

microorganisms but is also more able to remove cells from the root canal.Water is not

effective in removing dentine debris from grooves in the apical portion of root canals.

Disadvantages of NaOCl

Acute inflammation followed by necrosis results when NaOCl comes into contact with

vital tissue. It causes severe inflammation and cellular destruction in all tissues except

heavily keratinized epithelium.The cytotoxic effect of 5.25% NaOCl on vital tissues,

resulting in hemolysis, is well documented, and its use warrants proper care. The clinical

efficacy of NaOCl relates to its nonspecific ability to oxidize, hydrolyze, and osmotically

draw fluids out of tissues.

The severity of the reaction depends on the concentration of the solution, its pH, and the

duration of exposure. NaOCl has a pH of 11 to 12.5, which causes injury primarily by

oxidation of proteins. In high concentrations, severe necrotic changes could be

observed. The higher concentrations also have some irritating effects on the periodontal

ligament.One report cites periodontal side effects of NaOCl with lower

concentrations. However, when confined to the canal space as an intracanal endodontic

irrigant, clinical toxicity of NaOCl is no greater than the clinical toxicity of normal saline

solution.

NaOCl causes vascular permeability in blood vessels, probably as a result of damage to

the vessels as well as the release of chemical mediators, such as histamine, from involved

tissue. This characteristic causes immediate swelling and often profuse bleeding through

the root canal when NaOCl is not used properly as an endodontic irrigant.

There is only 1 report of hypersensitivity to NaOCl, which can easily be detected by skin

patch testing.There are reports about the effects of improper use of NaOCl, including

inadvertent injection into the maxillary sinus or splashing solution into the eyes. The

extrusion of NaOCl can cause facial nerve weakness in addition to other soft-tissue

damage.In addition to its toxicity to vital tissues, NaOCl has an unpleasant odor and

causes damage if it comes into contact with clothing.

There are 2 reports of inadvertently injecting NaOCl instead of anesthetic solution. One

resulted in severe palatal tissue necrosis,and the second involved edema in the

pterygomandibular space and peritonsillar and pharyngeal areas because of mandibular

block injection with NaOCl instead of anesthetic solution. In the second case, the patient

was admitted to an intensive care unit for probable airway obstruction and given opioid

analgesic intravenously for pain reduction.Damage to permanent tooth follicles,

peripheral tissue, and oral mucosa have been reported during careless NaOCl use in

pediatric endodontics.There are only a small number of cases in the literature that have

reported postoperative skin complications, long-term paresthesia, and altered nerve

sensations arising from the use of NaOCl as an endodontic irrigant.

There are 23 reported cases of NaOCl accidents in the literature. Almost all of

the cases have similar sequelae including severe pain, edema, and profuse hemorrhage

both interstitially and through the tooth. The reports mentioned several days of increasing

edema and ecchymosis accompanied by tissue necrosis and paresthesia; in some cases,

secondary infections have been observed. Most of the cases had complete resolution

within a few weeks but a few were marked by long-term paresthesia or scarring.

Remaining residual paresthesia indicates some permanent damage to the nerve endings in

the affected area.

NaOCl Accident Management

Proper management of a NaOCl accident is important for achieving the best outcomes.

The following lists some important factors for managing a NaOCl accident:

• Early recognition of the problem; the patient should be informed of the cause and

nature of the accident (Table 2, see end of the article)

• Immediate irrigation of the canal with normal saline to dilute the NaOCl

• Allow bleeding response to flush the irritant out of the tissues

• Reassure patient

• Provide patient with both verbal and written home care instructions

• Monitor the patient

After the NaOCl accident has been recognized and the patient has been informed, the

authors recommend a treatment that focuses on palliative care, including cold and warm

compresses, saline rinses, pain control, prophylactic antibiotics, steroid therapy, and

monitoring (Table 3). It is important to reassure the patient throughout treatment because

of the amount of time it will take for the inflammation to resolve.

Avoiding NaOCl Accidents

The following steps can help clinicians avoid NaOCl accidents:

• Adequate access preparation

• Good working length control

• Irrigation needle placed 1 mm to 3 mm short of working length

• Needle placed passively and not locked in the canal

• Irrigant expressed into the root canal slowly

• Constant in and out movements of the irrigating needle into the canal space

• "Flowback" of solution as it is expressed into the canal should be observed

• Use side delivery needles that are specifically designed for endodontic purposes

Discussion

NaOCl is tissue cytotoxic. When it comes into contact with tissue, it causes hemolysis

and ulceration, inhibits neutrophil migration, and damages endothelial and fibroblast

cells.Incorrect determination of working length, lateral perforation, and wedging of

the irrigating needle are the most common procedural accidents associated with adverse

NaOCl reactions.

The optimal clinical concentration of NaOCl is still controversial. A 1% concentration of

NaOCl provides tissue dissolution and an antimicrobial effect, but the concentration

reported in the literature has been as high as 5.25%.Evidence demonstrates that high

concentrations of NaOCl have enhanced antimicrobial activity.Irrigation time may

increase the antimicrobial effect of endodontic irrigants without affecting the surrounding

tissues. It has been found that 0.5% NaOCl had nearly the same bactericidal effect as

5.25% NaOCl when used for 30 minutes.

After a NaOCl accident, early and aggressive treatment is advocated to reduce potentially

serious complications. The use of antibiotics is recommended because there is a

possibility of tissue necrosis and infection.Steroids also may be useful.

Depending on the degree of injury, some cases might require surgical intervention. The

aim of any surgical procedure should be to provide decompression and facilitate drainage,

and to create an environment conducive to healing. The other advantage of surgery is

meticulous debridement of grossly necrotic tissue and direct irrigation of affected sites.

Conclusion

NaOCl is an effective antibacterial agent but can be highly irritating when it comes in

contact with vital tissue. Most of the reported complications occurred because of

incorrect determination of endodontic working length, iatrogenic widening of the apical

foramen, lateral perforation, or wedging of the irrigating needle. If a perforation or open

apex exists, then great care should be exercised to prevent a NaOCl accident or an

alternative irrigation solution should be considered.

Table 2—How to recognize a NaOCl accident

• Immediate severe pain (for 2-6 minutes)

• Ballooning or immediate edema in adjacent soft tissue because of perfusion to the loose

connective tissue

• Extension of edema to a large site of the face such as cheeks, peri- orbital region, or lips

• Ecchymosis on skin or mucosa as a result of profuse interstitial bleeding

• Profuse intraoral bleeding directly from root canal

• Chlorine taste or smell because of injected NaOCl to maxillary sinus

• Severe initial pain replaced with a constant discomfort or numbness, related to tissue

destruction and distension

• Reversible or persistent anesthesia

• Possibility of secondary infection or spreading of former infection

Table 3—How to treat a NaOCl accident

• Remain calm and inform the patient about the cause and nature of the complication.

• Immediately irrigate with normal saline to decrease the soft-tissue irritation by diluting

the NaOCl.

• Let the bleeding response continue as it helps to flush the irritant out of the tissues.

• Recommend ice bag compresses for 24 hours (15-minute intervals)to minimize swelling.

• Recommend warm, moist compresses after 24 hours (15-minute intervals).

• Recommend rinsing with normal saline for 1 week to improve circulation to the

affected area.

• For pain control

• Initial control of acute pain could be achieved with anesthetic nerve block.

• Acetaminophen-based narcotic analgesics for 3 to 7 days (NSAID analgesic should be

avoided to decrease the amount of bleeding into the soft tissues).

• Prophylactic antibiotic coverage for 7 to 10 days to prevent secondary infection or

spreading of the present infection.

• Steroid therapy with methylprednisolone for 2 to 3 days to control inflammatory

reaction.

• Daily contact to monitor recovery.

• In severe cases such as respiratory distress, accessing the local emergency service via

108 is appropriate.

• Reassure the patient about the lengthy resolution of the inflammatory reaction.

• Provide the patient with both verbal and written home care instructions.

• Monitor the patient for pain control, secondary infection, and reassurance.

Tooth avulsion & replantation

• Replantation is the technique in which a tooth is reinserted into the alveolus after its loss or displacement by accidental means
• The prognosis of the replanted tooth depends on the time elapsed between the avulsion and the time tooth was placed back into the socket &  the way tooth was carried to the dentist.
• If avulsion has occurred at a clean place than tooth can be placed back into the socket by the patient himself or by someone near to him,and can than rush to dental clinic nearby.But if tooth has avulsed in a place that is dirty like that of a playground or something like that than ask the patient to come immediately to the clinic with tooth in a storage medium.
• Various storage medium available are-Hanks balanced salt solution,isotonic saline and bovine pasteurized skim milk are the best available storage medium.Saliva and tap water can also be used as storage media but its must to note that neither saliva nor tap water are better storage media than hanks balanced salt solution or milk,if tooth is to be stored for more than 30 min. before replantation.
• When patient arrives to your clinic than first look for alveolar bone fracture or severe soft tissue injury and than  irrigate the socket with betadine and saline.At the same time keep the avulsed tooth in a doxycycline solution for 5 minutes.every attempt should be made to preserve viable periodontal ligaments in the socket and the root surface of tooth.Tooth should be place back into the socket by using digital pressure.If the clot is present in the socket,it will be displaced as the tooth is repositioned.If the tooth doesn't slip back on digital pressure than it can be forced by using local anaesthesia or a X ray can be taken.After this do a semi rigid splinting using a thin wire and composite.Keep patient on antibiotics and antiinflammatory and analgesic drugs.Also prescribe patient with tetanus toxoid injection.Keep calling the patient at regular intervals.Chances of re-vascularisation are greater when the apex is not closed and tooth is immature.But if apex is closed than RCT becomes mandatory and it should be carried out after the 7 days of injury,with splints are still there.Calcium hydroxide should be used as obturating material.It can be latter replaced by gutta percha but at least for a year calcium hydroxide should be used and it should be renewed after 6 months with fresh calcium hydroxide. 
• Rigid splinting should not be advocated as it can lead to ankylosis.
• Emdogain can be used to before placing the tooth into the socket.It improves the prognosis.
• Calcium hydroxide reduce the chances of external root resorption and it can also be used for closing the open apex of root.(apexification)
• If the time elapsed between the avulsion & replantation of tooth is more than one hour than remove all the dead periodontal ligaments from the tooth root surface and socket by irrigation with sodium hypochlorite.Soak tooth in sodium hypochlorite for 15 minutes.After that do RCT of the tooth outside the socket and Place the tooth in 2% stannous flouride for at least 5 minutes and than obturate the canal with calcium hydoxide.Doxycycline should also be used.After that place the tooth back into the socket and do semi rigid splinting for minimal 14 days period.

DIRECT PULP CAPING-contraindicated in deciduous teeth

DPC- DIRECT pulp caping cant be done in a deciduous teeth ….reason being is that when you place ca(OH)2 on the pin point pulpal exposure(iatrogenic)….it causes necrosis of the pulp in tht pin point area….this invoke inflammatory reaction inside that pin point region of pulp….now this inflammation can either be restrictd to tht area only or it can spread to whole pulp….this inflammation can attract OSTEOCLAST cells which can cause internal resorption of deciduous tooth….(MC DONALD AVERY DEAN 8^th edition pg.408)

MTA after mixing

MTA burnisher and condensor

MTA Carrier

Used to carry MTA in case of root end filling surgeries.

Clinical Application OF MTA

MTA-Mineral Trioxide Aggregate

MINERAL TRIOXIDE AGGREGATE

• Mineral trioxide aggregate is a new biocompatible material with numerous exciting clinical application in endodontics.
• MTA prevents microleakage, is biocompatible and promotes regeneration of original tissues when placed in contact with periradicular tissues or dental pulp.
• Marketed as Gray MTA(GMTA) and White MTA(WMTA).
• The main reason for introducing WMTA as a substitute for GMTA was to provide a hue matched more closely to that of the colour of teeth as opposed to contrasting Gray colour of GMTA.
• COMPOSITION: MTA consists of fine hydrophilic particles. The material is primarily derived from calcium oxide ,silicon dioxide , and aluminium oxide .It also contains trace amount of silicon dioxide ,calcium oxide, magnesium oxide,iron oxide, potassium sulphate and sodium sulphate.
• Differences in FeO concentration is thought to be primarily responsible for variation in colour of WMTA (off white )in comparison to Gray MTA GMTA was un aesthetic in cervical area of anterior tooth .
• MANIPULATION: Each pack of MTA comes with pre measured unit dose of water for convenience in mixing. To use MTA simply pour the powder onto pad supplied ,add water and mix to working consistency. Water powder ratio should be 3:1 according to manufacturer. Variation on part of water powder ratio could account for increased solubility and porosity of material.
• SETTING REACTION:On addition of water compound in MTA react to produce calcium silicate hydrate gel that is calcium hydroxide contained in a silicate matrix.
• SETTING TIME : 2 hours 45 min – 4 hours
• pH :10.2 at start of mix ,rises to 12.5 after 3 hours. In experimental setting MTA is capable of maintaining high ph for long time. The high pH of MTA could be of clinical significance when used in apical barrier technique since alkalinity creates a favourable environment for cell division and matrix formation. Due to high ph MTA shows antibacterial action similar to calcium hydroxide.
• SOLUBILITY:It has been shown that set MTA’s solubility is a function of water powder ratio (for optimum properties recommended w/p ratio is 3:1) MTA is mainly composed of a insoluble matrix of silica gel that maintains its integrity even in contact with water.
• SEALING ABILITY/MARGINAL ADAPTATION: The sealing ability and marginal adaptation of MTA outperforms other material compared (amalgam, Super EBA IRM e.t.c. ). A stable barrier to bacterial and fluid leakage is one of the key factors in creating clinical success of root repair material.
• Clinically a barrier of 3-5 mm should be considered if root end surgery is a treatment option.
• MTA’ s sealing ability and better marginal adaptation is probably due to its hydrophilic nature, longer setting time and slight expansion when it is cured in moist environment. MTA contains 5% gypsum that expands during setting contributing to better adaptation .
• REGENERATIVE CAPABILITIES Regeneration has been defined as the replacement of tissue components in the appropriate location, in the correct amount and the correct relationship to each other. This means reformation of the bone in the surgical site, adjacent to fully reconstituted PDL, attached to newly formed cementum, over resected root end and root end filling material.
• Clinically a barrier of 3-5 mm should be considered if root end surgery is a treatment option.
• MTA is not an inert material in a simulated oral environment, it is “ BIOACTIVE ”.
• ADVANTAGES :Biocompatible;Non toxic;Non resorbable;Good marginal sealing;No irritation to surrounding tissues;Stimulates hard tissue formation ;moisture insensitivity;Radio opaque
• DISADVANTAGES: Difficult to manipulate;Longer setting time;Need two appointments.

Apicoectomy/Root End Resection

An Apicoectomy, or Root-End Resection, is the removal of the root tip and the surrounding infected tissue of an abscessed tooth. This procedure may be necessary when inflammation and infection persists in the area around the root tip after Root canal treatment.

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Step one:

After the tooth is "numbed", the
gum is reflected (lifted) to uncover the underlying bone and the
root end of the tooth. The root-end is resected (removed) with all
the surrounding infected tissue.

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Step two:

A root-end filling is placed to seal the end of the root canal, the gum is repositioned, and a few dissolvable sutures (stitches) are placed to hold the gum tissue back in its place until healing occurs.

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Step three:

After a few months, the bone around the root-end has healed, and all symptoms are gone.