Root canal treatment (RCT) is common these days to save a decaying tooth. Root canal procedure involves the removal of nerve and pulp from the insides of the tooth followed by cleaning and shaping of the tooth. This step is helpful to treat the tissues near the tooth from getting infected and also to prevent abscesses formation.
A successful root canal treatment involves accurate diagnostics and the correct treatment plan. To achieve this, endodontists should know the appropriate anatomy of the teeth and their morphology. The tooth is cleaned and shaped and a proper obturation technique was used to complete the procedure. However, the seal allowed moisture and this lead to failures. Later research identified that improper cleaning and shaping leads to poor obturation of canals and failure of RCT.
How do Cleaning and Shaping Help in RCT?
- Canal preparation starts with cleaning and shaping.
- While retaining the tooth, one can feel irritation of the tissue leftovers as it is not possible to completely remove the microorganisms due to tooth anatomy and morphology.
- Cleaning the tooth for RCT is done to clean these irritants.
- Factors like canal curvature, canal wall irregularities, fins, etc. affect the cleaning process completely.
- Shaping is done to effectively remove canal contents and infective microorganisms. Post shaping, the tooth walls become glossy and smooth.
- The degree of shaping is estimated by the root dimension, the size of the obturation material, the obturation technique, and the restoration plan.
- The purpose of shaping tooth before RCT is to
- Facilitate cleaning
- To receive three-dimensional fillings of the root canal space
- Develop a tapering funnel from the canal orifice to the apex
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The Objective of Cleaning and Shaping
The main objectives of cleaning and shaping of the tooth are:
- Remove the infected hard and soft tissues along with bacteria and endotoxins.
- Irrigate the apical canal space with disinfectant.
- Create newly enlarged space for medicament delivery and obturation. This is done by opening the crown, removing the pulp, filling the root canal, and sealing the same.
- Retain radicular structures and original anatomy.
Cleaning and Shaping Techniques
- Cleaning of the canal is performed by irrigation. Oral irrigators were developed in 1962.
- It uses a jet of pressurized water to clean the harmful bacteria between the interdental and subgingival regions of the mouth.
- This reduces the severity of periodontal diseases.
- There is also a technique called pocket irrigation that reduces plaque and oral bacteria.
- The shaping of the canal is performed by instrumentation.
- Nickel-titanium files have been used for shaping the tooth as they are flexible and resistant to cyclic fatigue.
- They can be attached to a rotary handpiece and have increased taper compared to stainless steel files.
Off late, ultrasonics are used for cleaning and shaping teeth during RCT. The technique is known as acoustic micro streaming. In this technique, an ultrasonically activated file agitates the irritant and removes the debris from the cleaned tooth thereby increasing the effectiveness of RCT.