PROCEDURAL ACCIDENTS

Dr.Moeen Al Weshah

DEFINITION

Endodontic mishaps or procedural accidents

are those unfortunate accidents that happen

during treatment, some owing to inattention to

detail, others being totally unpredictable

TORABINEJAD AND LEMON IN “ENDODONTICS

PRINCIPLES AND PRACTICE” :

I. Perforations during access preparation

II. Accidents during cleaning and shaping

III. Accidents during obturation

IV. Accidents during post space preparation

Proper access opening is key to ensure an errorless procedure during cleaning and shaping, if not gained it would be beginning of procedural failure.

Main errors during access opening are

Access Cavity Perforations

Treatment of the Wrong Tooth

Missed Canals

Damage to an Existing Restoration

ACCIDENTS DURING ACCESS PREPARATION

The prime objective of an access cavity is to provide an unobstructed or straight-line pathway to the apical foramen.

Accidents, such as excess removal of tooth structure or perforation, may occur during attempts to locate canals.

Failure to achieve straight-line access is often the main etiologic factor for other types of intracanal accidents.

ACCESS CAVITY PERFORATIONS

CAUSES

A. Lack of attention to degree of axial inclination in relation to adjacent teeth or bone gouging and perforation usually through indirct visioin (cast crown)

*Could be avoided by periodic review of bur tooth relationship, transillumination, magnification and radiographs

B. Searching for chamber or canal orifices through underprepared access cavity

C. Failure to recognize when a bur passes through a small or flattened pulp chamber in multirooted teeth

RECOGNITION:

Sudden pain while local anesthesia was adequate

Sudden hemorrhage perodontium > bone? Dry field?

Burning pain or bad taste during NaOCl- irrigation

Reading on AL. RG mal-positioned file.

Early detection is vital to treatment as cleaning and shaping of PL or bone worsen the prognosis and resulted in severe postoperative pain

Inform your patient of questionable prognosis and refer to endodontist.

TYPES OF PERFORATION

DURING ACCESS CAVITY PREPARATION

Lateral root perforation Supracrestal easy repair full crown- covering the defect

Infracrestal repair-- poorest prognosis, ortho-extrusion

or periosurery. Or internal repair using MTA

Furcation perforation Direct: punched out defect if dry GIC or composite otherwise MTA

Immediately

Stripping: Furcation side of the coronal surface inner surface

i.e the opposite surface of the lateral perforation (multirooted)

this will lead to periodontal pocket. Failure will be due to leakage

of repair material. MTA improves the prognosis of nonsurgical repair

compared with other materials.

PREVENTION

Clinical and radiographical examinations

Tilted, misoriented casting, calcified chamber

Even 2D angulated RG give will give at least distorted 3D

Operative procedures Postpone RD application in difficult cases

Constricted chamber or canals must be sought with small amount of dentine removed at a time

Use safe non cutting edge burs after de-roofing the chamber (Endo Z, pulp shaper bur)

RG and AL to detect early perforation

Use split dam group isolation

A bur is secured in the hole with cotton pellet and RG taken: Direct facial RG and Angled RG

Use fiberoptic light to locate canals , direct light beam through the access and illuminate the pulp chamber

Use of magnifications loupes or microscope

TREATMENT:

Nonsurgical Prefered to surgical if possible, difficulties because of

visibility

hemorrhage

control, management and sealing ability of repair material

should be sealed immediately MTA best prognosis

Surgical Complex restorative procedures

Demand good oral hygiene

Options if bone level allows: bicuspidation or hemisection or intentional reimplantation (IR)

IR: consider if more than one problem present

PROGNOSIS

Depend on many variables:

Location

Length of root trunk

Size of the defect, <1 mm

Presence/absence of periodontal communication

Time lapse between perforation and repair

Sealing ability of restorative material

Competence of the dentist/patient oral hygiene

Treatment of the wrong tooth can be so easily prevented. One should make sure through testing, examining, and radiography that one has confirmed which tooth requires treatment

Open the access cavity before applying the rubber dam

TREATMENT OF THE WRONG TOOTH

Additional canals in the mesial

roots of maxillary molars and the

distal roots of mandibular molars

are the most frequently missed.

Second canals in lower incisors,

and second canals and bifurcated

canals in lower premolars, as well

as third canals in upper premolars

are also missed.

One must prepare adequate

occlusal access

MISSED CANALS

Porcelain crowns are the most susceptible to

chipping and fracture.

When one is present, use a water-cooled,

smooth diamond point and do not force the

bur, let it cut its own way .

Also, do not place a rubber dam clamp on the

gingiva of any porcelain or porcelain-faced

crown

DAMAGE TO AN EXISTING RESTORATION

ACCIDENTS DURING CLEANING AND SHAPING

Ledge formation

Root perforation

Artificial canal creation

Instrument separation

Extrusion of irrigation solution

Aspiration or ingestion and tissue emphysema

LEDGE FORMATION

Occur when WL can no longer be negotiated and canal patency lost

Causes:

Inadequate straight line access into the canal

Inadequate irrigation and lubrication

Excessive enlargement of curved canals with large files

Debris packing in canal ‘s apical portion

PREVENTION

I. PREOPERATIVE

A. curvatures: mostly severe coronal curvature. Apical curvature with improper access preparation

B. length: longer canals more prone than shorter

C. initial size: small diameter canals are more prone to ledging.

II: OPERATIVE:

optimum straight line access, frequent irrigation and recapitulation, good lubrication. flexible

files

1/8-1/4 REAMING motion in the apical part and away from furcation area. Each file should be

loose before next size is used.

MANAGEMANT AND PROGNOSIS

Management: size 10 ss, 2-3 mm sharply bent toward canal curvature, with good lubrication,

with picking motion. once original WL gained work with reaming motion and up and down to

remove debris

Prognosis: depend on amount of debris remains

Usually short and cleaned apical ledge have good prognosis

Should clinical or radiographic evidence of failure arises,

refer to endodontist

CREATING AN ARTIFICIAL CANAL

Causes: ledge, insist on WL , usually by ss files

Management: confirm WL AL,radiograph and PP

adjust WL and create a stop and obturate, how?

If there is no perforation: warm compaction

technique

Perforated: the defect should be repaired internally

with MTA or surgically

Prognosis:

depend on the ability to renegotiate, prepare and

obturate the original canal.

Renegotiated canals had good prognosis while un-

negotiated especially when large portion is missed

is poor. If symptoms arises, surgery to resect un-

instrument portion?

ROOT PERFORATION

Could be perforated at any level

A. Apical: overinstrumnetation:

Incorrect WL or inability to maintain WL cause zipping of apical foramen.

Signs: bleeding, pain, sudden loss of apical stop,

Prevention: take WL with apex locator and consider change of WL during/after CS

Treatment: establish new WL seat , use of MTA apically to prevent extrusion of filling materials

Success will depend on size and shape of the defect reverse funnel,

open apex, the need to interfere surgically will influence outcome.

B. Lateral Midroot perforatrion: inability to maintain curvature due to curvature plus size and inflexibility of larger files

Treatment, bypassed the ledge if possible and seal the perforation site, use mild irrigation concentration

Prognosis buccal has better prognosis. Corrective techniques include repair of perforation site, root resection to perforation level, root amputation, hemisection, extraction

C. Coronal root perforation: occur during access preparation as the operator try canal orifice or during flaring procedure with files GG

peeso reamer. Poorest long term prognosis

SEPARATED INSTRUMNET

Due to limited flexibility and strength combined with improper use (overuse or excessive force applied)

Recognition: the file comes out shorter than the length when it was inserted. RG: to confirm

Inform the patient

Prevention: knowing the limits of the instrument, copious irrigation, avoid instrument overuse, examine your instrument before insertion

Small files should be replaced frequently

Your set of files should be replaced if possible

NiTi show no signs of weakening

Unwound or twisted files should be replaced

Examine your instrument under magnification

SEPARATED INSTRUMNET Treatment:

Attempt to remove, bypass or up to the

segment if couldn’t bypass or remove.

Try to bend 2-3 mm of small size 8 or

10 s.s file as ledge treatment, if

bypassed you can use ultrasonics,

barbed broaches headstrom files to try to

remove the instrument

Prognosis:

How much undebridment before separation

and unobturated portion apical to the

instrument.

Poor prognosis if small files at apical portion

or beyond the apex.

Surgery should be considered if there are

symptoms.

EXTRUSION OF IRRIGANT

SODIUM HYPOCHLORITE ACCIDENT

Caused by wedging of the needle in the canal or sometimes out of perforation with forceful expression of the irrigant (NaOCl-) to periradicular tissues which could be a life threatening emergency.

Signs and symptoms: sudden prolonged and sharp pain followed by rapid diffuse swelling.

Prevention: keep irrigating needles loose in the canal, don’t wedge the needle, don’t make excessive force while irrigating and use proper(perforated) needles for irrigation

Use side vented needles not subcutaneous needles for irrigation

Treatment: palliative, sometimes analgesics anti-inflammatory medication with no antibiotics at initial management, reassurance, follow up on daily basis.

INSTRUMENT ASPIRATION OR INGESTION

One of the most serious mishaps

87% swallowed and the rest aspirated

The patient should be referred immediately to medical service

All aspirated and some swallowed will need surgical intervention by thoracic surgery or abdominal surgery

Relatively uncommon

Two actions may cause this to happen:

a blast of air to dry a canal

exhaust air from a high-speed drill directed toward the tissue and not evacuated to the rear of the handpiece during apical surgery.

Emphysema from a blast of air down the canal is more likely to happen with youngsters, in whom the canals in anterior teeth are relatively large.

The usual sequence of events is rapid swelling, erythema, and crepitus.

Although the problem should not be treated lightly, the majority of reported cases have followed a benign course to total recovery.

Prevention is simple: use paper points. Do not blow air directly

down an open canal, and employ a handpiece that exhausts the spent air out the back of the handpiece rather than into the operating field.

TISSUE EMPHYSEMA

ACCIDENTS DURING OBTURATION:

The quality of obturation reflects canal preparation (cleaning

and shaping) which is the key for proper obturation)

A. underfilling

Natural barrier

Ledge

Insufficient flaring

Poorly adapted master cone

Inaqedate condensation pressure this doesn’t mean using

excessive force on spreader or plugged which will result in root

fracture

Always take cone fit radiograph and if suspicious before you

sear excessive gutta percha.

Treatment: redo.

ACCIDENTS DURING OBTURATION:

B. overfilling

A consequence of over-preparation through apical constriction or lack of

proper taper in prepared canals

Either naturally (open apex, resorption) or due to over preparation will mean

absence of matrix against which to condense which will result in extrusion

of filling material due to uncontrolled condensation (compaction)

The presence of seat is necessary

Prevention: cone fit RG

Treatment: redo if possible, surgery

Prognosis will depend on quality of apical seal , biocompatibility of

extruded, host response, toxicity and sealing ability of the root end filling

material

C. Vertical Root Fracture

Etiology

Causative factors include root canal treatment procedures and associated factors such as post placement. The main cause of vertical root fracture is post cementation, and the second in importance is excessive application of condensation forces to obturate an underprepared or overprepared canal.

Prevention

As related to root canal treatment procedures, the best means of preventing vertical root fractures are appropriate canal preparation and use of balanced pressure during obturation. A major reason for flaring canals is to provide space for condensation instruments.

Finger spreaders produce less stress and distortion of the root than their hand counterparts.

Indicators

Long-standing vertical root fractures are often associated with a narrow periodontal pocket or sinus tract stoma, as well as a lateral radiolucency extending to the apical portion of the vertical fracture.

To confirm the diagnosis, a vertical fracture must be visualized. Exploratory surgery or removal of the restoration is usually necessary to visualize this mishap

Accidents during obturation:

To prevent root perforation, gutta-percha may be removed to the desired level with heated pluggers or electronic heating devices

Attempting to remove gutta-percha with a drill only can result in perforation.

When a canal is prepared to receive a post, drills should be used sequentially, starting with a size that fits passively to the desired level.

preparation may result in perforation at any level.

indicators

Appearance of fresh blood during post space preparation is an indication for the presence of a root perforation.

The presence of a sinus tract stoma or probing defects extending to the base of a post is often a sign of root fracture or perforation.

Radiographs often show a lateral radiolucency along the root or perforation site.

ACCIDENTS DURING POST SPACE PREPARATION

Treatment and Prognosis

the prognosis of teeth with root perforation during post space preparation depends on the root size, location relative to epithelial attachment, and accessibility for repair.

Management of the post perforation generally is surgical if the post cannot be removed. If the post can be removed, nonsurgical repair is preferred .

Teeth with small root perforations that are located in the apical region and are accessible for surgical repair have a better prognosis than those that have large perforations, are close to the gingival sulcus, or are inaccessible.

ACCIDENTS DURING POST SPACE

PREPARATION

PROTECTION GLASS