Errors in endodontic cavity preparations & their management Dr. hadil abdallah altilbani

Endodontic errors are not common problem in our daily endodontic practice but definitely a very embarrassing situation which may occur during endodontic procedures like: Access cavity preparation. Biomechanical preparation of the root canal system.

Errors are: Coronal perforation: Lateral perforation: Cervical perforation Mid root perforation Apical perforation Bifurcation perforation Ledge formation Transportation Gouging : Zipping : Elbo

Coronal Perforation Causes:  Anatomic configuration  Inclination of tooth  Difficult accessibility  Mis direction of bur Detection:  Saliva comes in the access cavity  Irrigation solution goes into the mouth  Patient notice the unpleasant taste

Management Needs immediate repair Isolation of the tooth Free from contamination Intracoronally repaired by using cavit

Cavit Zinc oxide calcium sulphate, zinc sulphate, glycol acetate, polyvinyl acetate resin, polyvinyl chloride acetate, triethanolamine, colour pigment

Lateral of perforation (Cervical) Causes Mis direction of bur Inappropriate use of Gates Glidden Drill deep in the canal During location of canal orifice Detection: Bleeding in the access cavity Radiograph (Place a file through the opening and a radiograph is taken for the confirmation that the file is not in the canal)

Lateral of perforation (Cervical)

Management : Isolation of the tooth Free from contamination Control of Bleeding Location of perforation Location of the canal orifices Insertion of the thickest file in the canal opening up to 5mm below the level of perforation.

Calcium hydroxide paste (Dycal) is packed into the perforation and allowed to set Soft mix of amalgam is gently packed over the calcium hydroxide paste. After Initial setting of the filling material the file is gently removed. RCT should be perform as conventional method.

Prevention: In the Anterior teeth the direction of bur should be parallel in the long axis of the tooth in all plans. In molar teeth bur should be directed towards the large canal orifice. The use of bur should be limited to the roof of pulp chamber.

Bifurcation perforation

Bifurcation perforation: Causes : Mis direction of bur Careless use of instruments Inadequate study of the tooth both clinically and radiographically Detection : Profuse bleeding in the pulp chamber Radiograph (Place a file through the opening and radiograph is taken for the confirmation that the file is not in the canal.

Cementoenamel = chamber ceiling D= 6.0mm F= 1.5 -2.0mm A= 3.0mm Cementoenamel = chamber ceiling %97% - 98

Furcation Entrance Entrance: the transitional area between the undivided and the divided part of the root Fornix: the roof of the furcation

Management Immediate repair to minimize of the injury tooth and supporting tissue. Control of Bleeding Location of perforation Calcium hydroxide paste (Dycal) should be packed into the perforation area and allowed to set.

Soft mix of amalgam is gently packed over the calcium hydroxide paste. RCT should be perform as conventional method. Prevention : Through study of the anatomic configuration The use of bur should be limited within the pulp chamber

Mid root perforation (Striping)

Mid root perforation (Striping) Stripping is a lateral perforation caused by over instrumentation through a thin wall in the root canal & is most likely to happen on the inside or concave wall of a curved canal.

Causes : Over zealous instrumentation in the mid-root areas Not use precurved instruments. Identification : Appearance of blood Sudden complain of pain by the patient

precurved instruments

Precurvature of instruments

Management: Both internal and external repair may be required. A small area may be sealed from inside the tooth. A large one required surgical repair. International re-implantation can be considered.

Prevention : Careful exploration and instrumentation. Straight line access to orifice. The flexible files (Ni-Ti files) should be used. Large diameter instruments should be avoided. Use precurved instrument.

Apical perforation

Apical perforation Identification : Causes : Uncontrolled instrumentation Ledge formation Identification : Sudden appearance of fresh bleeding from the canal. Pain during canal preparation. Sudden loss of apical stop.

Management : Established a new working length. Creation an apical seal. Obturation to its proper working length.

Ledge formation

Ledge formation Causes: Insertion of uncurved instruments. Large instrument out of sequence. Inflexible instrument in curved canals. Poorly designed access cavity. Over enlargement of the curved canals.

Indefication: Instrument should be no longer be inserted into the canal to the full working length. Loss of normal tactile sensation of the tip of instrument binding in the lumen which confirm hitting a solid wall

Management : Location the ledge by a radiograph and verification the depth Irrigate the canal copiously Explore the ledge area with a small file No 6, 8, 10, 15 in which a precurvature has been made form the tip extending about 3 mm up the blade. The curved tip should be pointed toward the wall opposite the ledge.

Once the ledge is bypassed start circumferential filling till be ledge is removed Use a lubricant irrigate frequently to remove the dentine chips If the ledge cannot be bypassed then clean, shape and obturate the canal at that level If endodontic treatment fails then alternative treatment such as roof end filling hemisection may be considered.

Prevention : Accurate radiograph study Awareness of canal morphology Use of flexible file pre curved instruments should be used Working length should be followed

Transportation : It may be defined as removal of canal wall structure on the outside curve in the apical half of the canal due to the tendency of the files to restore themselves to their original linear shape during canal preparation.

Prevention : Pre curved instruments should be used Use of smaller or flexible files, safety files Anticurvature filling should be done.

Transportation :

Causes : Rotary action of instruments Due to apical curvature of root Management : Instruments should be used in a half circle rotary action Flexible file should be used

Gouging : When an instrument is used with complete rotating action in the apical curvature, a cavity is formed is called gouging.

Zipping Over preparation of the outer wall of the apical curvature of the canal with inflexible instruments will cause zipping.

Zipping : Causes : Failure to used the precurve the instruments Rotation of instruments in curved canals Use of large stiff instruments Treatment : When a zipping is present theremoplasticized GP techniques preferred along with Surgical approach can be consider.

Elbow The narrowest part of the preparation is short of its apical extent & is known as elbow. In most case, the obturating material will terminate at this elbow, leaving an unfilled zipped canal apical to the elbow.

Elbow

Irrigant-Related Mishaps Injection of full-strength sodium hypochlorite out of the apical foramen.

tissue emphysema caused by injecting hydrogen peroxide irrigant into the tissues

Instrument Aspiration and Ingestion