Austin T's Profile

first premolar

medial to the second molar

slightly bow the needle

few drops

ess than a fourth to a third of a cartridge

just posterior to the incisive papillae

The technique requires flexible files with non-cutting tips. The file is inserted into the canal until slight resistance is felt and then rotated 60° clockwise to engage the flutes into the dentine.

Using light apical finger pressure to hold the file at exactly the same depth in the canal, the file is now rotated through 360° in an anticlockwise direction

There is no longer any need to dry the canal before use as they work in the presence of electrolytes.

modern apex locators can be even more accurate in length determination than a radiograph.

access cavity

rubber dam

pre-operative radiograph

First, the pulp chamber is copiously irrigated with sodium hypochlorite. Gates–Glidden burs are next introduced into the canal, directed apically and laterally away from the furcation. The larger sizes are introduced first, working sequentially further down the canal with smaller sizes

Most operators now confirm the actual working length when the crown-down preparation has progressed to within 3 or 4 mm of the estimated working length.

A size appropriate to the particular canal and the final size Gates–Glidden drill is selected, perhaps a size 60, the tip dipped into a canal lubricant, and the instrument worked slightly further into the canal. Sequentially smaller files are selected until the canal is prepared to 3–4 mm short of the estimated working length. Now the actual working length must be confirmed by one of the methods described earlier, radiograph or apex locator. Once the working length has been confirmed, the apical preparation can be completed. In narrow or sclerosed canals the operator may prefer to take a small 08, 10 and 15 files to working length before commencing any canal preparation. The prepared canal then acts as guidance for the larger sizes.

The master apical file will usually be no greater than 25 or 30.

Hand Files of Greater Taper

Stepdown technique

the initial movement to engage the dentine with these files only is a 60° turn anticlockwise, and the balanced force cutting motion is 360° clockwise.

the canal must first be gently explored to length with conventional 2% taper hand files. A gentle watchwinding technique is used with size 08, 10 and 15 files.

largest file with a blue handle and a taper of 12%, is used first to gain coronal access.

When resistance is met the instrument is not forced further apically, but the red handled 10% taper file is used to penetrate further.

The yellow handled 8% taper and white handled 6% taper follow in sequence, until the canal is prepared to working length.

Once a smooth-tapered canal has been prepared, the clinician may consider it necessary in some cases to enlarge the apical constriction slightly with conventional hand files.

The technique of patency filing involves passively inserting a small file, size 08 or 10, 2 mm beyond the established working length. No attempt is made to instrument the foramen, merely to keep it open or patent by deliberately extruding the debris into the periradicular tissues.

No research workers have been able to show either a decrease or an increase in post-operative symptoms or case prognosis.

There is almost universal agreement that when an intervisit dressing is required, calcium hydroxide is the material of choice

There is far less agreement as to whether such dressings are indicated. Single-visit endodontics — the shaping, cleaning and obturation of the root canals in one appointment — remains controversial. Most endodontists would agree that when the tooth under treatment is not infected, for example when performing elective endodontics or treating large exposures of vital pulps, completing treatment in a single visit is advisable.

Cavit has been shown to provide the best seal.

On the other hand, it lacks strength and will not stand up to masticatory forces. It should be confined to single surface fillings for periods not exceeding a week.

the use of a glass-ionomer cement should be considered. It is adhesive, antibacterial,

It is a useful routine, with an inter-appointment dressing, to place a sterile pledget of cotton wool in the pulp chamber, followed by a layer of gutta-percha. The temporary restorative material is then placed over the gutta-percha