ACCIDENTS AND INCIDENTS OCCURRING DURING OCE THERAPIES

Introduction

Like other complex disciplines of dentistry, endodontic treatment can generate unwanted or unforeseen events that can affect the prognosis. These mishaps are collectively referred to as operative accidents and incidents.

I/ Accidents related to the use of anesthesia:

1/ local accidents a/Painful injection

Causes
- Injection too fast with very high pressure;
- Solution temperature too cold,
- Poor choice of anesthetic technique,
- Mucous membrane not stretched,
- Nerve damage.
Prevention
- Perform contact anesthesia in children and anxious patients,
- Heat the cartridge,
- Apply sharp traction to the cheek or lip,
- Avoid bone contact causing painful periosteal detachment,
- Orient the single bevel of the needle in the direction of the bone,
- Inject slowly,
- Inject away from the source of infection.

b/ Needle breakage

Causes

Technical error by the practitioner,

Sudden movement of the patient especially in children.

Action to take

Reassure and warn the patient, ask them not to close their mouth, to limit mandibular and swallowing movements to avoid secondary penetration of the needle.

Visible fragment: extraction possible in the office with hemostatic forceps,
Submucosal fragment:
- Take an X-ray (retro-alveolar, panoramic),
- Mark the entry point with a marker and refer the patient to a maxillofacial surgeon, with a prescription for antibiotics.

c/ Hematoma/Hemorrhage Two cases may arise:

In a subject with a normal hemostasis assessment, if a hematoma appears at the injection site, its resorption is rapid;
When the hematological balance is disturbed, regional or local anesthesia should be avoided.

in loose tissues (floor of mouth).

d/Nerve injury: Rare incident

Facial paralysis and eye problems may occur.

These impressive accidents are short-lived and leave no after-effects, but if the problem persists, refer the patient to a neurologist.

e/Irritation or ischemia of the oral mucosa

At the point of infiltration, the mucosa turns white and then takes on a purplish tint and 7 days later a painful loss of substance appears in the form of an ulceration.

Causes:

Topical application of surface anesthetic, Excess vasoconstrictors,

Injection speed too fast, Injection pressure too high,

Anesthetic temperature too cold,

Infiltration into a thin (lingual) or very adherent (palatal) mucosa.

Action to take:

Prescribe a mouthwash as well as an antiseptic and healing ointment

Prevention

Warm the anesthetic solution; No excess pressure;

Slow injection.

f/Septic complication: this type of complication is rare.

Causes: oral environment with numerous infectious foci.
Action to take:

Perform surgical drainage of the infection; Prescribe: broad-spectrum antibiotic therapy.

e/Soft tissue injury

Causes:

Prolonged anesthesia, which causes involuntary trauma to the lips; tongue by biting, especially in children and disabled people.

Action to take:

Perform sutures if necessary;

Prescribe mouthwash, painkillers, and possibly antibiotics.

2/General accidents a/Vagal discomfort or lipothymia

It occurs in emotional, tired, anxious subjects, it is favored by the sitting position, the most

often it is triggered from the start of the injection.

Signs and development: Its onset is gradual; the subject feels the discomfort coming, associates with it more or less

less to:

Dizziness;
Feelings of hot flashes;
Tinnitus;
Visual disturbances;
A feeling of heaviness in all his limbs;
The subject is clinically pale with sweating, polypnea, and bradycardia.

When loss of consciousness occurs, it is very brief.

Vasovagal syncope can be prevented by giving the patient a calming premedication administered

2 hours before local anesthesia.

Treatment: This requires lying the patient in a supine position and elevating their legs, which facilitates cerebral irrigation. Atropine injection is very rarely useful.

b/Cardiorespiratory syncope

This is a very short cardiorespiratory arrest, with loss of consciousness occurring from

brutal way.

The patient is motionless, pale, inert, the pulse is not perceptible and there is no breathing.

Evolution :
- Favorable if it is less than 1 minute and reversible leading to a sudden awakening with resumption of circulation;
- Unfavorable beyond 3 minutes.
Action to take:
- Perform cardiopulmonary resuscitation;
- Contact emergency services.
Prevention:
- Possible sedative premedication;
- Respect the doses.

c/Convulsive crisis : It is most often due to an overdose or an intravascular injection, clinically there is a premonitory syndrome which should be the alarm signal: malaise with anxiety, headaches, yawning, nausea, agitation or drowsiness, pallor, sweating, etc.

The crisis is generally brief but can recur in the absence of treatment with risk of

collapse.

Prevention:
- Good interrogation;
- Choice of anesthesia with respect for dose and concentrations;
- Monitoring patient reactions during administration of the anesthetic product;

d/Allergic accidents

Allergy is an abnormal, inappropriate, exaggerated reaction of the immune system occurring after exposure to an allergen, due to the use of allergenic molecules: anesthetic molecule, preservatives.

The allergic reaction appears 3 to 5 minutes after the injection, it includes cutaneous signs such as pruritus then more or less generalized urticaria, tachycardia, sharp epigastric pain then collapse, bronchospasm,

What to do in the event of an allergic reaction:
- Stop treatment immediately,
- Contact emergency services,
- Administer oxygen to the patient,
- Control the upper airways,
- Inform the patient and record the event in their medical record.
Prevention:
- Complete a good medical questionnaire,
- Refer the patient to an allergist if necessary.
- Combine a vasoconstrictor which allows:
  - Increase the duration of action of anesthesia,
  - Decrease vasodilation, absorption rate, toxicity, injected dose and bleeding.

II/ Accidents during the creation of the endodontic access cavity

When opening the pulp chamber, three types of accidents can be highlighted.

1/ Instrumental blockage : This involves partial removal of the pulp ceiling.

The causes:

Lack of knowledge of endodontic anatomy;
Misreading of the preoperative x-ray.

The practitioner will have to reread the preoperative X-ray and remove using a pointed burr

foam the remainder of the pulp ceiling.

2/ Stop

It is the excessive elimination of the pulp ceiling that gives rise to blockages. This accident is due to the same etiologies as the previous one.

The abutment can lead to weakening of the walls, thus increasing the risk of coronal fracture. In the event of this accident, the practitioner should consider coronal filling with glass-ionomer cement and redoing the endodontic access cavity to create a four-walled cavity. 3/Perforation

Depending on their orientation we can distinguish two types of perforations:

External (coronary) perforations are due to:

inadequate instrumentation,
a lack of knowledge of dental anatomy,
a dental malposition.
- Internal perforations (of the pulp floor), include:
from the lack of knowledge of pulp-radicular morphology
insufficient extension of the endodontic access cavity,
the presence of intrapulpal calcifications.

The course of action:

In case of small perforation:

Washing the surgical wound with physiological serum;
Hemostasis and tamponade;
Application and light condensation of calcium hydroxide or MTA on the wound;
Application of a glass ionomer cement which will protect the calcium hydroxide followed by root canal filling.
In case of extensive perforation: The prognosis is uncertain. Surgery, amputation involving the removal of a tooth root, or dental extraction are required.

III/ Accidents during cleaning and canal shaping 1/ Instrumental fracture: The etiologies are:

excessive fatigue of the endocanal instrument;
scraping carried out with the application of excessive force to the instrument;
unfavorable anatomical factors (angled canal).

The anatomical location of the fragment, confirmed by the retroalveolar radiograph, dictates the course of action to be taken.

🡺 Therapeutic abstention :

If the fractured instrument is sterile, all aseptic measures have been observed and the canal obturation will ensure all the qualities of a hermetic obturation.

🡺 Mechanical therapies : These are indicated for cases where the fractured instrument is located

in the upper third (the most favorable case) or middle third of the canal.

Side rubbing method:

Carry out the bypass of the instrumental fragment, under abundant irrigation of chelating solution (EDTA, Largal ultra, strong acids (hydrochloric acid) and iodine trichloride) using pre-bent MMC 0.6 or 0.8 files, after flaring the coronal portion of the canal .

Once the passage has been obtained by the MMC files, the use of MME files from 0.6 to 15 will allow the removal of the instrument.

MASSERANN method:

He had the idea of extracting the fragment of the instrument by introducing a tube around it which encases it

and which allows it to be taken out.

In fact, the Trepan tube is introduced into the canal and will be turned by hand and will progress until it comes into contact with the fragment and then will encompass it.

For this, prior preparation of the canal is necessary to allow the engagement of the

tube.

A mandrel sliding in the trephine tube wedges the fragment by forcing it against a window

arranged: the stuck instrument is then extracted.

Note: The drill tube can only be used in a relatively straight canal.

Surgical therapies

Many surgical methods can be considered depending on the clinical case presented to the practitioner.

🡺 Apical resection:

When the fractured fragment is located in the apical third of a surgically accessible root.

🡺 Root amputation:

Reserved mainly for lower molars except in the case of root fusion

2/ Dentin plugs

The dentin plug is made up of organic debris pushed back by instruments pushed too quickly without irrigation, to which are added dentin chips from an untimely cut of the file.

Causes:

Inexperience
Excessive precipitation
Failure to comply with the fundamental rules of canal preparation in terms of irrigation

and instrumental maneuvers.

According to Laurichesse, the prevention of the formation of dentin plugs follows five rules:

Abundant and renewed irrigation;
Use of instruments in ascending order without ever skipping a number;
Summary by the last instrument freely reaching the apical limit after use of each file number;
Absence of rotational movements of the instruments in the canal, the action of which is limited to one eighth of a turn;
Flexible use of instruments, without ever forcing.

The removal of a dentin plug can be achieved by using pre-curved 0.8 MMC, with significant irrigation, combining the action of a solvent such as RC Prep and sodium hypochlorite to partially dissolve the plug or at least soften it.

Once the passage is obtained with the MMC, work for a long time with an MME of the same diameter to enlarge the passage. As soon as it is sufficient, use a sonic instrument to completely free the canal, and facilitate the action of larger diameter instruments.

3/ Shoulders or projections

They are created by the uncontrolled action of the files at the level of the middle third or the apical third.

a/Middle third shoulders

Action to take:

Pre-bend a 0.8 MMC file on its last millimeters to make a tight bend,
Coat the canal with RC Prep to facilitate the progression of the instrument, go until it contacts the shoulder, then rotate the file a few degrees and gently push it in the apical direction until it crosses the shoulder.
Once the apical limit is reached, a control X-ray should be taken.
Shoulder attenuation is achieved by using MMEs from 0.8 to 15/100, operated in back-and-forth movements, under abundant irrigation.

b/ Shoulders of the apical third

Their origin may be similar to that of the middle third, and in this case the solutions will be identical. However, most often these shoulders are created by the use of rotating files of too large caliber, not pre-bent, in curved canals. Prevention is ensured by respecting the basic principles, cited by Laurichesse.

4/ Root perforations: Roots can be perforated at different levels during cleaning and shaping.

The location of the perforation (apical, middle, or cervical) and the stage of treatment affect the prognosis.

/Apical perforations Etiology
- Instrumentation of the canal beyond apical constriction.
- Incorrect measurement of working length or failure to observe it during

canal preparation. This can be revealed by:

Bleeding that fills the canal or is visible on the files,
A painful sensation during the entire preparation of the canal while the tooth was asymptomatic,
Sudden loss of root pulp cavity preparation stop;
Radiographic image of the final file extension of the preparation beyond the apex image.

Prevention

Correct measurement of the working length and its observance during the entire preparation of the root pulp cavity.

Treatment : The procedure is as follows.

Depending on the diameter and location of the apical foramen, stop the working length at 1 or 2

mm below the hole of the perforation.

Clean, shape, then seal the canal, respecting this new working length.

The master cone should be firmly seated on the newly formed apical stop at the new working length.

To prevent extrusion of filling materials, it is advisable to seal the foramen

apical with the MTA to create a barrier between the pulp cavity and the periapical region.

/Lateral perforations (half root) Etiology

Misdirected pressure and forces applied to a file lead to the creation of artificial canals.

Indicators for lateral perforations are similar to those for apical perforation. The exit of the instrument from the root visible on radiography is the ultimate indicator. Treatment

Establish a new working length in the accessible segment of the canal.
Clean, shape, and then seal the canal to the new working length.
Irrigate the perforated canal with saline or low concentration solution (0.5

%) of sodium hypochlorite

Prognosis

Success depends partly on the volume of residual root cavity that could not be

prepared and sealed.

/Perforations of the coronal third of the root

Etiology Perforations of the coronal third of the root occur during the preparation of the

access cavity when the operator attempts to locate the canal entry ports, or during canal flaring maneuvers with files, Gates-Glidden burs, countersinks, or Peeso reamers.

Treatment

The prognosis is poor, an attempt must be made to seal this lesion internally, and the patency of the main canal must be protected during the healing process.

5/Hemorrhages

The causes of intraoperative bleeding can be limited to three reasons:

Laceration of pulp tissue,
Repeated crossing of apical limits by instruments,
Puncture and choking.

Prevention: For Laurichesse, four criteria must be respected:

Early establishment of precise apical limits;
Respect of the working length determined by all instruments;
Sodium hypochlorite irrigation;
Do not undertake root canal treatment if a significant periapical lesion is in the acute phase and presents significant transcanal purulent discharge;

In case of infectious problems, it is preferable to adopt a more ecological therapy with a pre-treatment step, which allows the desmodont to be de-inflamed and the canal to be disinfected, thus limiting the risks of complications.

Sudden hemorrhage during preparation This generally indicates a desmodontal injury.
- Stop the bleeding with a sodium hypochlorite bath for 4 to 5 minutes, before resuming the normal course of preparation.
- In the case of perforation, the aim is to find the canal path. If this is not possible, the false canal must be sealed with calcium hydroxide, which will ensure hemostasis and maintain disinfection of the endodontic tissue until a subsequent session, where it will be essential to find the canal and perform the definitive sealing of the perforation and the canal system.
- If this second attempt fails, all that remains is to extract the tooth or resort to endodontic surgery.
Bleeding at the end of preparation

It is caused by the passage of an instrument or an absorbent paper point through a very large or overly wide foramen.

The bleeding must be stopped with a hypochlorite bath, dried using fairly wide paper points, marked with the canal length, a stop cone must be made and carefully closed.

Heavy and stubborn bleeding

If washing with sodium hypochlorite proves ineffective, lime water can be used for washing or the canal system can be filled with calcium hydroxide for a few days; this is an easy and extremely effective solution.

6/ other accidents

Ingestion accident

This is the uncontrolled fall of a foreign body into the digestive tract. The symptoms depend on the nature of the foreign body.

Painful discomfort,
A foreign body sensation,
Dysphagia,
Chest or abdominal pain,
Vomiting.

It can also be silent and in this case it is the dentist who must think about it.

diagnosis with observation of the disappearance of the object and therefore suspicion of ingestion.

Inhalation accident

This is the uncontrolled fall of a foreign body passing into the respiratory tract

Symptomatology

Difficulty breathing that disappears spontaneously
Expulsive cough,
Abnormal respiratory noise

In the event of an ingestion or inhalation accident, the dentist must stop treatment, place the patient in a sitting position and reassure them .

The need for transport to the emergency department to perform the tests

complementary.

Prevention: the use of a surgical field dam

Extrusion of the irrigant: this accident occurs when performing endodontic treatment on:
- Immature teeth;
- Mature teeth with wide foramen;
- Teeth whose apical constriction has been destroyed by root canal preparation or by

the existence of a resorption process;

Or jam a needle into the canal, exerting strong pressure on the irrigant (usually sodium hypochlorite).

Prevention:

Use of a purpose-specific side-opening irrigation needle

endodontic;

Maintaining complete freedom of the needle which must never be stuck in the canal;
Slow and continuous injection of the solution associated with a continuous vertical movement of back and forth

comes from the needle in the canal;

Pressureless injection;
Continuous check of the reflux of the irrigation solution in the canal in the direction

coronary.

Symptoms of solution penetration into the periradicular tissues are immediate; this is manifested by sudden, acute, and prolonged pain followed quickly by diffuse swelling. This acute episode gradually fades over time.

The treatment is palliative, the patient must be reassured; if necessary, a prescription for painkillers is given.

will be prescribed.

IV/ Accidents during root canal filling 1/ Incomplete filling

Etiology

Natural barriers located in the canal,
A stop created during preparation,
Insufficient flare,
An improperly fitted master cone and inadequate gutta percha condensation pressure. Treatment and prognosis

It is best to remove all the filling material and properly retreat the canal.

2/Exceeding

Etiology

Excessive instrumentation of apical constriction,
Natural opening of the apex by apical resorption,
Incomplete root development.

Prevention: Compliance with the rules for preventing perforation of the apical foramen region. Treatment: Removal of the extruded material by surgical intervention to free it from the apical tissues and to seal the apical end with a biocompatible material.

3/Vertical fracture of the root

Etiology: The main causes are handling errors during root canal treatment and

other maneuvers such as the accommodation and sealing of root post.

Prevention: The application of well-balanced forces during obturation maneuvers. Treatment: Extraction of the affected root in a multirooted tooth and extraction of the single-rooted tooth are the only possible treatments.

V/Post-operative complications

Among these episodes, it is necessary to distinguish those which occur during the preparation of pulped teeth and those which occur during the treatment of periapical lesions or necrotic pulps.

Pulped teeth: In the case of pulpectomy:
- Absolute maintenance of the sterility chain,
- Respect of apical structures.

Indeed, the puncture of the periapical tissues can cause, apart from hemorrhage, septic inoculation of the periapex or provoke an inflammatory reaction, resulting from circulatory disorders caused by the instrument protrusion.

Performing a pulpectomy under irrigation reduces the risk of sepsis, but may cause reactive inflammation if the irrigating solution exceeds the acceptable toxicity threshold; hypochlorite should not exceed a concentration of 2.5%.

The use of temporary medications should be limited to placing a minimal amount of antiseptic in the pulp chamber on a cotton ball. Wicks or antiseptics that are too concentrated or too irritating (formaldehyde derivatives) should never be used.

Treatment: Complete the treatment, that is, perform the root canal filling after checking the apical limits.

In the event of a clear infection of the periapex, due to failure to follow the asepsis chain, treatments normally intended for necrotic or infected teeth must be applied.

An inflammatory reaction may also occur after root canal filling.

In the presence of a mild acute reaction, the filling must be checked and redone if it is imperfect; otherwise, analgesic and anti-inflammatory medication will be sufficient to make the symptoms disappear within a few days.

In the presence of a severe reaction, it is necessary to unblock, rinse the canal abundantly with physiological serum, fill it with calcium hydroxide, and resume the obturation the following week.

Dead teeth

Simple uncomplicated pulp gangrene

Clinically silent, this is certainly the situation most conducive to acute inflammatory episodes.

This reaction is caused by the practitioner, who, through overly untimely maneuvers, will

disturb the unstable balance of this environment.

Apart from prescribing painkillers, anti-inflammatories and antibiotics, it is advisable to completely re-trim and close the tooth after placing intracanal medication.

Acute apical periodontitis:
- Canal shaping under abundant irrigation of all canals,
- Close the coronary cavity,
- Place the tooth under occlusion.
Acute apical abscess (draining pus)

if the channels are accessible:
- Transcanal drainage
- Disinfection and instrumentation
- Leave open for 48 hours
if the channels are inaccessible:
- Drainage sought by trephining the bone cortex

Conclusion

Endodontic practice is a mix of successes and failures. To be rewarding, it requires an analysis of the factors that led to the outcome.

The constant improvement of our technology, based on respect for fundamental biological principles, should make it possible to limit failures and complications and to push back the limits of endodontics .