cons complications

Endodontic Complications

Definition

  • mishaps / accidents that occur during treatment.

  • can result from a lack of attention or be completely unpredictable

Classification of Endodontic Mishaps

  1. access related

    • treat the wrong tooth

    • missed canals

    • damage existing restoration

    • access cavity perforations

    • crown fractures

  2. instrumentation related

    • ledge formation

    • cervical canal perforation

    • midroot perforations

    • apical perforations

    • separated instruments + foreign objects

    • canal blockage

  3. obturation related

    • over- or underectended root canal filling

    • nerve paresthesia (temp. nerve pressure → numbing / pins + needles)

    • vertical root fracture

  4. miscellaneous (various other options)

    • post space perforation (hole made post preparation)

    • irrigant related

    • tissue emphysema (air leaked into soft tissue + trapped → swelling, cracking)

    • instrument aspiration + ingestion

Classification of accidents

  • during access preparation

  • during cleaning and shaping

  • during obturation

  • during post space preparation

Accidents During Access Preparation

  • Correct access opening = very ! for error-free procedure during cleaning and shaping.

    • otherwise → beginning of procedural failure

  • Main errors:

    • treat the wrong tooth

    • missed canals

    • damage existing restoration

    • access cavity perforations

Treating the Wrong Tooth

  • easily preventable (testing, examining, x-ray)

  • open access before rubber dam

Missed Canals

  • often miss:

    • extra canals in mesial roots of upper molars (6: MB1,MB2;7: M (1,2)) + distal roots of lower molars (both 3 (d,mb,ml)

  • lower incisors (1): second canals

  • lower premolars (1): second/bifurcated canals

  • upper premolars (4:2;5:1/2): third canals

  • its important to prepare adequate occlusal access

Damage to Existing Restorations

  • Porcelain crowns = most susceptible to chipping + fracture.

    • no rubber dam on gingiva or these crowns (+ porcelain-faced crown)

  • use: water-cooled, smooth diamond point bur. DON’T FORCE the bur — let it cut its own way

  • no rubber dam on gingiva of any porcelain or porcelain-faced crown

Access Cavity Perforations

  • main goal of the access cavity: to ensure an unobstructed, straight-line path to the apical foramen

  • Accidents, e.g., excessive removal of tooth structure, can occur during canal localisation attempts.

  • Failure to achieve straight-line access = main etiological factor for other types of intracanal accidents.

Causes of Perforation

  • The pulp chamber is usually located in the center of the anatomical crown of the tooth. (despite anatomic variations)

  • The pulp system = located in the long axis of the tooth

  • carelessness in assesing axial inclination of tooth (more mesial, distal, bucal etc) → gouging or perforation of crown / root (either too thin wall on one side / perforate it)

    • need to compare inclination of tooth in relation to adjacent teeth + alveolar bone

  • check orientation of access opening, otherwise → perforation

    • need to periodically check bur-tooth relationship

Operative Procedures

  • better crown-root alignement possible when initiate access wo. rubber dam

  • when bur passes through roof of pulp chamber can sometimes not be realised when chamber = calcified

    • → gouging or perforation of furcation

  • after penetrating root chamber: use safe-ended access bur (no perforation of chamber floor)

  • use apex locators + angled x-rays to detect early perforation

    • early detection → ↓ damage cuased by continued treatment + → improved prognosis for nonsurgical repair

  • use good light source

  • magnifying glasses / operative microscope can aid in locating small orifices

Mishaps During Cleaning and Shaping

  • Most common procedural mishaps:

    1. Ledge formation

    2. Artificial canal creation

    3. Root perforation

    4. Instrument separation

    5. Extrusion of irrigant periapically

  • correct = difficult

  • stiff instrument tends to straighten within curved RC → ledge formation, zipping or perforation

Ledge Formation

  • creation of a ledge → WL can’t be negotiated + original patency of canal is lost

  • Main causes of ledge formation:

    1. Insufficient straight-line access to the canal

    2. Inadequate irrigation / lubrication

    3. Excessive enlargement of a curved canal w. files

    4. Packing debris in the apical part of the canal

Ledge Prevention

  • Canals most at risk are small, curved, and long.

  • Key procedures:

    1. Straight-line access

    2. Accurate measurement of WL

    3. Frequent recapitulation and irrigation

    4. lubrication

    5. 1/8 → ¼ reaming motion (twist + pull)

    6. filing motion away from furcation → form funnel shape of cannel (reduces coronal curvature)

    7. each file must be used till its loose before using a larger size

Artificial Canal Creation

  • Deviating from the original path of canal → artificial canal

  • create a ledge + lose proper WL

  • trying to retain that WL, operator creates artificial canal

  • file can perforate root surface

  • most common cause: agressive use of steel files

Root Perforations

  • can take place at different levels during cleaning + shaping

  • location(: apical, middle, cervical) + stage of treatment affect prognosis

  • apical perforations

    • occur through apical formamen (over instrumentation)

    • occur through body of root (perforated new canal)

  • over instrumentation → “zipping” or “blowing out” of apical foramen

  • indicators of foramen perforation:

    • fresh hemorrhage in canal

    • pain during canal prep. in asymptomatic tooth

    • sudden loss of apical stop

Separated Instruments

Etiology

  • Limited flexibility + strength of instruments and improper use → intracanal instrument separation.

  • Main causes: overuse / excessive force applied to file

Recognition ie sign that its separated

  • removing shortened file with blunt tip

  • loss of patency to original length (ie. blocked at original length)

  • need x-ray to check

Prevention

  • Recognising the physical properties and stress limitations of files is key.

  • Continued lubrication using irrigation solutions or lubricants

  • check each instrument before using (flutes distortion)

  • often replace small files

  • minimise binding (use each file till loose → next file size)

  • nickel-titanium files dont show fatigue like steel file “untwisting” → replace before visual sign

Treatment

  • Three approaches can be applied:

    1. Attempt to remove the instrument

      • if can’t → clean canal, shape + obturate to new WL

    2. Attempt to bypass it

      • use ultrasonic file broaches or H-file to remove segment

      • if can’t → prep + obturate to new WL

    3. Perform obturation to the coronal level of the instrument.

Prognosis

  • depends on amount of undebrided + unobturated canal apical to + including file remains

  • best when separation occurs in later stage of preparation (+) close to WL

  • poorer prognosis for undebrided canals w. small instrument separated short of apex or beyond apical foramen early in prep.

  • patient must be informed (medical + legal reasons)

  • if still symptomatic / → failure → surgery

Irrigant Extrusion

  • (forcefully) Pushing the needle in canal / out perforation w. irrigant → penetration of irrigant in periradicular tissue → inflammation + patient discomfort

  • need: loose placement of iirgiation needles w. careful irrigation w. light pressure / use perforated needle → no into periradicular tissue

  • sudden prolonged / sharp pain during irrigation → rapid diffuse swelling = sign of penetration of solution into periradicular tissues

    • “sodium hypochlorite accident”

Aspiration or Ingestion of instruments

  • serious event but easily avoided

  • use rubber dam

  • if in alimentary tract / airway → immediate referral to medical service

  • surgical removal: some swalloed, nearly all aspirated

Tissue Emphysema

  • rare

  • causes:

    1. blast of air to dry canal

      • more likely in younger patients (larger canals in anterior teeth)

    2. exhaust air from high-speed drill directed towards tissue + not evacuated to rear of handpiece during apical surgery

  • Symptoms: rapid swelling, erythema and crepitus.

  • most cases: benign course to total recovery

  • prevention: paper points. dont blow air down open canal. use handpiece that doesn’t push spent air out the front (instead towards the rear)

Accidents During Obturation

  • Proper cleaning and shaping = key prevention

  • main cause: improper canal prep.

Underfilling

  • Causes: natural barrier in the canal, ledge, insufficient flaring, poorly adapted master cone, inadequate condensation pressure.

  • treatment: remove underfilled gutta-percha + retreat

    • if lateral condensation was used can use master cone to indicate WL

Overfilling

  • extruded obturation material → tissue damage + inflam.

  • postoperative discomfort lasts few days

  • causes: overinstrumentation, apex = naturally open / constriction is removed during cleaning + shaping (no matrix against which to condense), inflammatory resoprtion, incomplete develop. of root

Vertical fracture

  • causes: RCT procedures, post placement, main cause: post cementation, second: excessive application of condensation forces to obturate and under/over prepared canal

  • prevention: proper canal prep, balanced pressure during obturation,

    • finger spreaders > hand→ less stress + distortion of the root

  • indicators: narrow periodontal pocket, sinus tract stoma, lateral radiolucency extending to apical portion of vertical fracture

  • confirm: explatory surgery or remove restoration → visualise

Accidents during post space preparation

  • remove gp w. special instruments attached to post set → prevent perforation

    • if drill → perforation  

  • when canal ready for post: use drills sequentially (first size that fits passively to desired length)

  • can result in perforation at any level

  • indicators: fresh blood, sinus tract stoma, probing defects extending to base of post, x-ray: lateral radiolucency along root / perforation site

  • treatment: surgical if post can’t be removed, prefer non-surgical

  • prognosis: depends on root size, location relative to epithelial attachemnt + accessiblity for repair, small root perforation in apical region + accessible for surgery = better prognosis than large, close to gingival sulcus or inaccessible