Endodontics

If a small exposure of the pulp (or near exposure) of the pulp occurs during cavity preparation calcium hydroxide is placed over the pulp to allow time for secondary dentine to from over the pulp. The calcium hydroxide kills bacteria and promotes remineralisation.

Pulpotomy – the partial removal of the pulp, usually for deciduous molars or immature permanent incisors.

Pulpotomy is the term for removal of the coronal pulp with the intent of maintaining the vitality of the remaining radicular pulp tissue.

Indications:

• Large proximal carious lesion with involvement of marginal ridge
• No history of spontaneous pain
• Absence of abscess or fistula
• Where extraction is contraindicated
• Vital tooth with healthy peridontium

• Cream or topical anaesthetic will be applied to the gums to numb the area. Once the gums are numb, the local anaesthetic will be administered.
• A rubber dam will then be placed to isolate the tooth and reduce saliva moisture.
• A highspeed and slow-speed handpiece will be used to clean the cavity.
• The coronal pulp will be removed by excavation
• A medicament will then be applied to stop bleeding
• The chamber will be filled with recommended material
• The tooth is then covered with a crown.

• Partial pulpotomy for traumatic exposures (Cvek pulpotomy)

• The partial pulpotomy for traumatic exposures is a procedure in which

• The inflamed pulp tissue beneath an exposure is removed to a depth of one to three millimeters or more to reach the deeper healthy tissue

Indications:

• This pulpotomy is indicated for a vital, traumatically-exposed, young permanent tooth, especially one with an incompletely formed apex. Pulpal bleeding after removal of inflamed pulpal tissue must be controlled. Neither time between the accident and treatment nor size of exposure is critical if the inflamed superficial pulp tissue is amputated to healthy pulp

Objectives: The remaining pulp should continue to be vital after partial pulpotomy. There should be no adverse clinical signs or symptoms of sensitivity, pain, or swelling. There should be no radiographic signs of internal or external resorption, abnormal canal calcification, or periapical radiolucency post-operatively. Teeth with immature roots should show continued normal root development and apexogenesis.

This deciduous molar has a carious exposure of the pulp, but the pulp is still alive.

The caries and the coronal part of the pulp are removed, leaving vital pulp tissue in the root canals.

The pulp is now capped and a restoration placed.

These upper incisors are immature, the root is still developing and the apex is “open”. The crowns have fractures, the pulp has been exposed but it is still alive. Part of the pulp has been removed and the pulp capped to encourage the root to continue to develop.

1. Orthograde root fillings

These incisors have a single root with one root canal. The root canals have been completely filled with a root filling.

  This molar has 3root canals which have been sealed with root fillings.

A root canal treatment is undertaken when the only alternative is an extraction.

Reasons for RCT:

• pulp death and abscess formation
• carious exposure which would lead to pulp death
• uncontrollable pain due to pulpitis
• fractures that involve the pulp chamber
• if a post is required to retain a crown i.e. when there is not enough of the clinical crown remainings

Treatment involves:

• Radiographs to assess the tooth
• Accessing all the root canals
• Determining the root canal length
• Widening the root canals
• Removal of all pulp tissue (extirpation)
• Thorough disinfection of the canals (irrigation)
• Drying the canals
• Sealing the canal with a root filling and paste sealant (obturation)
• Final radiograph to assess result and for reference to assess success later

Factors affecting decision to do endodontic treatment or extract:

• Medical History
• Degree of difficulty and likelihood of success
• The ability to restore the tooth after RCT
• The value of the tooth (is the tooth in occlusion?)
• The alternatives to restore a gap if the tooth is extracted
• The overall condition of the patient’s mouth
• The patient’s wishes, including ability to pay for treatment

After treatment the tooth will need a restoration that not only protects the seal of the root canal but also prevents fracture of the weakened tooth. Onlays or crowns will be required on molars and premolars to prevent cusp fractures.

NB Rheumatic fever, congenital heart defects and heart valve surgery no longer exclude patients from having RCT and they no longer require antibiotic cover prior to treatment.

Extraction advised for patients who have:

• Learning difficulties – because these patients might be unable to cope with long treatment sessions
• Chronically sick and frail elderly patients – because these patients might be unable to cope with long treatment sessions

RCT advised for patients who have:

• Epilepsy – because patients are unable to wear dentures
• Bleeding disorders – because there is a risk of post extraction haemorrhage
• Suppressed immune system e.g. chemotherapy – because of high risk of infections with extractions
• Drug therapies for osteoporosis – because bone death and severe infections may occur after extractions
• Cleft palate – because of retention of teeth and prevention of need for a denture

2. Retrograde root fillings

This incisors had a normal orthograde root filling placed through the crown of the tooth. The apex of the tooth has been removed surgically and a filling placed at the apical end of the root canal.

Apicectomy involves surgery to locate and remove the apex or apices of a tooth. Infected granulation tissue around the apex of the tooth is also removed. Apicectomy is undertaken as a last resort to save a tooth. Wherever possible it is better to do conventional root canal therapy and also to re-do the treatment if it has been unsuccessful.

Reasons for apicectomy and retrograde root fillings:

• Persistent periapical infection despite repeating RCT
• Canals blocked by
• Post crown
• Fractured root canal instruments
• Sclerosis (secondary dentine)
• Removal of fractured root apex
• Removal of inaccessible apex e.g. with very curved roots

NB Specialist endodontists have the expertise to solve some of the above problems without the need for an apicectomy. The dentist may refer a patient for specialist treatment.

1. Local anaesthetic is given
2. Rubber Dam is fitted over the tooth

• holes are made in the rubber dam with a rubber dam punch
• the rubber dam clamp is fitted into the hole or onto the tooth
• the rubber dam is placed on the tooth
• the rubber dam is stretched taut over a rubber dam frame

Advantages of using a rubber dam:

• protection of the airway. No risk of small hand instruments falling into the throat
• isolation of the tooth from oral microbes prevents reinfection of the root canal
• improved access and visibility for the dentist
• the taut rubber dam helps the patient to keep their mouth open for long sessions

3. An access cavity is cut to locate the pulp chamber and root canals
4. The working length of the canal is determined by either:

Taking a periapical radiograph with the diagnostic files in place. The length of file is known and its position to the apex is assessed on the radiograph. It is generally accepted that the working length is 1mm short of the apex.

Or as the file is advanced along the canal, an electronic apex locator indicates when the constriction just short of the apex is reached. The apex locator may have sounds when the apex is located as well as giving a visual reading.

5. The root canal is shaped. The entrance to the canal is widened and tapered towards the apex. Hand or rotary files, in an endodontic handpiece, of ever increasing size are used to shape the canal.

6. The canal is disinfected. Disinfectants are flushed through the canal system to remove tooth and pulp debris and kill microbes. Sodium hypochlorite or chlorhexidine are mostly commonly used for irrigation. Ultrasonics may be used with the disinfectants to improve debris removal and to warm the sodium hypochlorite which increases its effectiveness.

8. Obturation (filling and sealing the root canals). Gutta percha (GP) points, matching the size of the files, are the most common root filling material used. The aim is to virtually fill the canals with GP. A slow setting sealant paste holds the GP in place and fills any small voids. Condensation of the GP may be cold, using finger spreaders or lateral condensers, or warm, using thermal GP points or applied heat such as System B. Multiple GP points in place and a finger spreader used for lateral cold condensation. Excess gutta percha that protrudes from the canals will be removed with a hot instrument.

9. The tooth is X-rayed to check that the root filling is satisfactory and as reference for progress and healing.

10. A temporary filling that provides good coronal seal is placed prior to the final restoration.

• Application of local anesthetic to reduce pain and discomfort
• A hole will be drilled to access the pulp
• The pulp is then removed from the roots
• The tooth will be cleaned, disinfected and filled with the prescribed materials
• A crown will be placed to cover the tooth
• The dentist will prescribe antibiotics to reduce the risk of infection
• Pulpectomy is a root canal procedure for pulp tissue that is irreversibly infected or necrotic due to caries or trauma
• A pulpectomy is indicated in a primary tooth with irreversible pulpitis or necrosis or a tooth treatment planned for pulpotomy in which the radicular pulp exhibits clinical signs of irreversible pulpitis (e.g., excessive hemorrhage that is not controlled with a damp cotton pellet applied for several minutes) or pulp necrosis (e.g., suppuration, purulence). The roots should exhibit minimal or no resorption.

• Teeth with non-restorable crowns
• Extensive pulp floor opening into the bifurcation
• Excessive internal resorption
• Primary teeth with underlying dentigerous or follicular cysts

A barber broach is a thin, flexible metal hand instrument used to remove – extirpate inflamed pulp tissue. Handles – colour coded according to size.

The Reamer file is similar to K-file, but its cutting edges are farther apart. Function is to increase the size of the canal. Handles are colour coded according to size.

Endodontic spreader is used to obturate the canal. Obturation is the process of filling a root canal. The condense and adapt the gutta-percha points into the canal. Has pointed tip. Working end has rings in milimeter increments. Different sizes available. Endodontic spreader is used exclusively on endodontic tray setups.

A finely tapered, smooth-surfaced, flexible hand instrument used to laterally condense gutta-percha points during root canal therapy. Handles are colour coded according to size.

K- files has a twisted design and is used in initial debridement (cleaning) of the canal and during the later stages of shaping and contouring canal. Handles are colour coded according to size. The purpose of the debridement and shaping of the canal are:

• to remove bacteria, necrotic tissue, and organic debris from the root canal
• to smooth and shape the canal so that the filling material can be completely adapted to the walls of the canal

Hedstrom file provides greater cutting efficiency because of its design. H-type file has its spiral edges arranged so that cutting occurs only on the pulling stroke, making the dentinal walls smooth and easier to fill. Handles are colour coded according to size.

Used by dentists when performing root canal treatments. These instruments are used to clean and shape the root canal. Latch type shank is used with slow-speed contra-angle handpiece. Handles – colour coded according to size.

It helps to gain access to the root by enlarging walls of pulp chamber and opening canal orifice. Latch type shank is used with slow-speed contra-angle handpiece. Different sizes – coded by rings or coloured bands on shank. They are slightly flexible and will follow the canal shape but can perforate the canal if used too deeply.

It’s function is to place endodontic sealer or cement in root canal for final seal before placement of gutta-percha. Latch type shank is used with slow-speed contra-angle handpieces. Lentulo spiral is exclusively used on endodontic tray setups.