GROUP 2 A1) SAABIRAH KHADEEJAH MOHD SIDEK2) SALWATUL IZZRA BINTI MAHADI3) SITI RAZAN BINTI RAMLI4) SITI FATIMAH BINTI MOHD KAMAL

INTRA-RADICULAR PREPARATION ERRORS (CANAL BLOCKAGE & LEDGE)

I - CANAL BLOCKAGE

This condition occurs when the operators feel that working length and canal patency is loss and is due to apical pushing lead to packing of tissue or dentinal debris which has been removed during cleaning and shaping.

Clinical appearance : - Full working length cannot be reached because the instruments are working against the packed mass at the apex. A radiograph will confirm this suspicion.- At area of blockage canal feels sticky due to aggregation of debris.

Etiology :- Failure to maintain full working length during preparation.- insufficient irrigation .- Lack of recaputilation during preparation.

Prevention : - Always use smaller sized instruments first.- Use instruments in sequential order.- Always pre-curve stainless steel hand instruments.- Use copious amount of irrigants and always work in wet canal.- Use reproducible reference points and stable silicon stoppers on instruments while cleaning and shaping.

Treatment & Management :

1- Operator should irrigate the canal and start negotiating the canal at full working length using the initial file (smallest file reaching the working length).

2- Ultrasonic irrigation maybe very beneficial in steering-back the accumulated debris and facilitate its removal by irrigants. Also the alternate use of hypochlorite/peroxide solutions with the resulting bubbling effect may help removal of blocking debris.

3- Correction is made by recapitulation—starting with finer instruments used in a quarter-turn motion. Adding a chelating agent such as EDTA is helpful.

II - LEDGE

Among the complications most commonly observed during root canal instrumentation is a deviation from the original canal curvature without communication with the periodontal ligament, resulting in a procedural error termed ledge formation or ledging.

Clinical Appearance :- Instrument can no longer be inserted into the canal to the full working length. - Loss of normal tactile sensation, a feeling that the instrument is no longer engaging the walls. Stop! Take a radiograph with the instrument in place.

Etiology : - Insertion of uncurved instruments.- Large instrument out of sequence. - Inflexible instrument in curved canals.- Not extending the access cavity sufficiently to allow adequate access to the apical part of the root canal.- Over enlargement of the curved canals. - Complete loss of control of the instrument- Incorrect assessment of the root canal direction- Erroneous root canal length determination - Forcing and driving the instrument into the canal- Failing to use the instruments in sequential- Rotating the file at the working length (that is, overuse of a reaming action) .- Inadequate irrigation and/or lubrication during instrumentation - Over-relying on chelating agents- Attempting to retrieve broken instruments- Removing root filling materials during endodontic retreatment- Attempting to prepare calcified root canal.- Inadvertently packing debris in the apical portion of the canal during instrumentation (that is, creating an apical blockage)

Prevention : - Be careful and attentive during the instrumentation process.- Use of accurate preoperative and “working” radiographs to determine the root canal length, copious irrigation, precurved files, and incremental instrumentation .- Awareness of canal morphology.- Use of flexible file.- Pre curved instruments should be used.- Working length should be followed.- Newer instruments with non-cutting tips have materially reduced this problem. The rounded tip does not cut into the wall but slips by it.

Treatments & Managements :

1- Location the ledge by a radiograph and verification the depth

2- Irrigate the canal copiously

3- 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.

4- The curved tip should be pointed toward the wall opposite the ledge.

5- Once the ledge is bypassed start circumferential filling till be ledge is removed

6- Use a lubricant irrigate frequently to remove the dentine chips *Do not use ethylenediaminetetraacetic acid (EDTA) for chelation because it tends to intensify

the ledge.

7- If the ledge cannot be bypassed then clean, shape and obturate the canal at that level

8- If endodontic treatment fails then alternative treatment such as roof end filling hemisection may be considered.