Endodontics and Canal Anatomy

A technique used in root canal preparation that involves working from the apical end of the canal towards the coronal end using progressively larger files.

The narrowest point of the root canal, often coinciding with the cementodentinal junction (CDJ).

A technique used in root canal preparation that involves working from the coronal end of the canal towards the apical end using progressively larger files.

The distance from the incisal edge or cusp tip to the apical constriction.

A technique used to widen the coronal portion of the canal before determining the final working length.

The initial file used to determine working length. It should be the largest file that can reach the full working length.

The point at which the root canal preparation meets the apical constriction.

The largest file that reaches the full working length after using the initial file.

A technique used to shape the root canal by using a sequence of instruments of increasing size.

The process of using smaller files to clean and shape the apical area before using larger files.

A procedure that uses instruments to remove debris and bacteria from the root canal.

A technique used to determine working length by inserting a file to the full length and then back until it becomes loose.

A type of instrument used to enlarge the coronal portion of the root canal.

The first phase of root canal preparation, focusing on preparing the apical constriction.

An instrument used to remove debris and bacteria from the root canal.

Preparing the apical area with files up to 3 sizes larger than the initial file, followed by recapitulation.

A common deviation from the canal where the instrument tip creates its own exit out of the root from aggressive instrument activity.

A deviation from the canal that occurs when the instrument cuts laterally against the root wall, often in areas known as 'danger zones.'

A deviation from the canal that occurs at the very tip of the root, often caused by over-instrumentation.

A deviation from the canal that can occur anywhere, where the instrument tip gets stuck or trapped.

A small, stiff instrument (size 15 K-File) used to remove an obstruction from the root canal by rotating it circumferentially to detect a catch, and then rotating it with a slight in-and-out motion to bypass the obstruction.

The space between the root canal wall and the particles of the obstruction, which is detected when rotating the instrument to find the blockage.

A radiograph taken after the instrument has passed the obstruction to ensure it is correctly positioned and the root canal is being negotiated to the desired length.

The process of using a file to remove pulp tissue and debris from the root canal. It is done after the obstruction is bypassed and the working length is established.

Chelating agents, like EDTA, are used to soften and dissolve the dense blockage, made of dentin chips, allowing easier passage of the file.

Sodium hypochlorite, a chemical agent used as an irrigant during root canal preparation. It dissolves organic tissues and removes debris, aiding in canal cleaning.

The apical third of the canal may be filled with dentin chips, preventing proper sealing.

Frequent irrigation with sodium hypochlorite helps clean the canals and prevent debris buildup.

A type of drill used to widen the coronal portion of the root canal. It helps prepare the canal entrance for further shaping.

A thin, irregular layer formed on the dentin surface during instrumentation. It comprises various components like dentin debris, odontoblastic processes remnants, pulp tissue, and bacteria. It acts as a barrier, impeding the penetration of disinfectants and bonding of filling materials.

The smear layer is a barrier that prevents proper penetration of disinfecting agents into the dentinal tubules. It's a physical obstruction, hindering the disinfectants from reaching their target.

The smear layer can prevent a tight seal between the root filling and the canal walls, leading to potential leakage and re-infection.

It's debatable whether the smear layer should be removed completely. Some argue for its removal to allow for better disinfection and bonding. Others believe retaining it may help prevent leakage and seal in vital tissues.

Removing the smear layer allows disinfectants to effectively reach the dentin tubules and eliminate bacteria. This leads to better canal preparation and may reduce the risk of re-infection.

Retaining the smear layer might prevent leakage and micro-organisms from penetrating the root filling. It can protect the vital tissues and reduce the risk of postoperative sensitivity.

The decision depends on factors like the specific case, clinical judgment, and patient needs. It's important to weigh the advantages and disadvantages before deciding on the course of action.

The smear layer is a complex structure with controversial roles in root canal treatment. It's important to understand its properties and its impact on disinfection and sealing to make informed decisions regarding its removal or retention.