What Are We Trying to Achieve by Root Canal Treatment

8/8/2019 What Are We Trying to Achieve by Root Canal Treatment

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What are we trying to achieve by Root Canal Treatment?

-restoring everything.

-lesion healing.

-final restoration.

*Access Cavity:

*Major Objectives:1-Conservation of tooth structure.

2-Deroofening of the pulp chamber.

3-Attainment of straight line Access.

Outline form of the access cavity:

-Must be an extension of the canal projection to the occlusal surface.

-Should reflect the internal anatomy of the tooth.

-Often variations in the internal anatomy dictate the modification in the external outline.

N.B. No rubber dam No R.C.T.

1-Conservation of tooth stucture.

-minimal weakening of the toth structure.

Prevention of accidents.

2-Deroofening of the Pulp Chamber:

-removal of pulp chamber roof ,use explorer to check the access cavity.

Advantages:

-easy cleaning.

-Maximal visibility.

-Location of canals nicely.-improve Straight-line access.

-Expose pulp horns.

-done by round or diamond bur or endo z.

N.B.profuse bleeding occurs with perforations.

-The deeper the position of the perforation the worse the prognosiscoronal and apical

perforation have better prognosis than perforation in the middle third.

-If perforation occurredstop drillingdry the filedassess restorability either

1-seal the perforationobturation.

2-seal the perforationobturaionperiosurgery (for perforation in coronal third).

3- seal the perforationobturaionendosurgery (for perforation in apical third).

4-extraction if the tooth is not restorable (usually for perforation in middle t hird).

3-Attainment of straight line Access.

-Improve instrumentation control without touching canal wall (passive).

-Minimal weakening of the tooth structure.

-Improve obturaion.

-Decrease of accidents and errors.



Errors:

-ledge.

-perforation.

-stripping.

-zipping.

-apical perforation.

Access Cavity Preparations:

-Using any bur you are comfortable with (

i.e. round bur,

Endo Z with safety tip, Diamendo)

GG

Access cavity in special situations:

I -Caries:-All caries should be excavated before accessing the pulp chamber prevent bacteria and

infection to go inside the canal.

-if the tooth is badly destructed and you cant place the rubber dam do

Crown lengthening

Use matrix, ortho band, or copper band or crown.

Build the tooth up with glass ionomer.

II-Gingival overgrowth.

-If there is soft tissue over growth perform gingivectomy caries excavation, fillingplace

rubber dam,R.C.T.

III-Altered internal anatomy

IV-C-shaped canals.

-Occur mostly in mandibular 2nd molars.

-N.B. dont use air to dry the canals you may cause emphysema.

-With c-shaped canals use ultra sonic scaler and /or higher concentration of sodium

hypochlorite.

*alfouzan in 2002nfound that C-shaped canals occurred in 10.6 % of Saudi population ,

and it occurred more in mandibular 2nd molars.

V-Crowned teeth:

-it is better if you remove the crown before starting the R.C.T to avoid perforation .

-But if you have to do access through the crown --> start the access in the middle of the

crown, and then incline the bur with the long axis of the tooth as in the radiograph.

VI-Prepared teeth:

For prepared teeth, some time you will do the access from occlusal rather than lingual (i.e

in attrition cases).

Or from the previously bucall access to conserve tooth structure and /or preserve the

finish line.



Outline:

Maxillary Central Incisors :

-Triangle or oval, wide M-D

-Usually two pulp horns and one canal.

-There are reported cases of c-shaped canals, two ,and three canals in maxillary incisors.

-Remove lingual dentin ledge to get S.L.A.-In older age patients the pulp horns decrease and may disappear (especially in lower

anterior teeth).

N.B. never uses high-speed burs inside the canals.

Maxillary Lateral Incisors:

-Oval.

-two pulp horns.

-mainly one canal , but the canal is curved laterally.

Mandibular Incisor:

-Oval.-Expect two canals 42%.

-Usually its easier to locate the buccal canal due to the orientations of the tooth. So look

closely for the lingual canal.

-Inspect in the x-ray if there is sudden disappearance of the canal second canal.

Maxillary Lateral Incisors:

-Oval.

-two pulp horns.

-mainly one canal , but the canal is curved laterally.

Maxillary Canine:

-Oval.-One pulp horn.

-Longest root, usually one canal.

-No reported cases of two canals.

Mandibular Canine:

-Oval.

-Reported cases of two canals are very rare.

Mandibular Canine:

-oval .

-usually one canal but there is reported cases of two canals.

Maxillary Premolar:

-Oval with two pulp horns (the highest placed buccal ly).

-Usually two canals (the canals usually placed slightly on the mesial side).

-6% incidence of 3 canals and three foramen in maxillary premolars.

-2008, ateya momen found that number of ROOTS in maxillary 1st premolar:

18% one root.

80.9% two roots.

1.2% three roots.



And the number of CANALS:

8.9% one canal.

89% two canals.

Mandibular Premolars:

-oval-large pulp chamber

- Upper lateral incisor and mandibular premolars are the most difficult in root canal

treatment due to the curvature of the canals and roots (lateral) and the bifurcation

(premolar).

-35% of mandibular 1st premolar has two canals.

-Reported case in 2001 by alfouzan of mandibular 2nd premolar with two roots and four

canals.

Maxillary 1st molar:

-Trapezoid or triangle.

-The paltal root (P) usually curved bucally.

-The mesiobuccal root (MB) has two canals in 60-75%.

-The Distobuccal root (DB) majority has one canal.

-alnazhan in 2005 reported 23.3% of MB2 (4 canals) in maxillary 1 st molar in SAUDI

population.

-can be

-Reported case in 2009 of two palatal canals, another case in 2010 reported the occurance

of two palatal roots (6 canals MB1,MB2,DB1,DB2,P1,P2)

-on the mesial side try not to cross the oblique ridge.

Maxillary 2nd molar :

-MB root has 2 canals by 40-50 %.

-DB and P root majority has one canal.

-in 1996 study stated that 6.9% of maxillary 2 nd molar has two roots with two canals (B,P)

-reported case in 2009 of maxillary 2nd molar with 5 canals ( 3 MB,DB,P)

N.B. dentinal floor darker than axial dentin

Mandibular 1st Molar:

-Triangle or trapezoid according to pulp chamber anatomy and pulp horns.

-alnazhan in 1999 reported that 57.6 % of 4 canals in mandibular 1 st molar in Saudi

patients .

-reported cases of three canals in the mesial root 2MB,1ML.

3 mesial , 2distal

4 mesial ,2 distal

Mandibular 2nd molar:

-mesial root majority has 2canals.27% type 1

-Distal root majority has one canal and12-15% has two canals.



Working length determination:

*Reference point:

-Selection.-Stability.

*Technique for determination:

-Estimated working length.

-Corrected working length.

Estimated working length usually shorter than radiogph by 2-3 mm, then you take x-ray

and assess, With the knowledge that the average root length usually 19-21 mm (except

canines).

*Alternative technique:

1-electronic apex locator.

2-feeling apical constriction.

3-patient response.

Method 1 is the most reliable with accuracy of 80-95 % method (best is root ZX),while

method 2+3 are not..

Where do we have to stop at the radiographic apex or anatomic apex?



We have to stop at the minor constriction at the cementodentinal junction and usually its

about 0.5-1.5 mm from radiographic apex.

-Kuttler in 1955 found that:

The canal end usually 0.5 mm shorter than radiographic apex.

He also stated that the apical foramen usually not found at the apex but rather laterally.

The apical foramen founded to coincide with apex in 26% only andlaterally in 74%.N.B. in case of older patien the canal will end shorter due to i ncreased cementum

thickness.

Also in case of periapical lesion or root resorption the canal will end shorter up to 2mm

from radiographic apex.

Buccal Object role (SLOB)

-Done by changing the direction of the x-ray cone so he physician can integrate the

different superimposed canals.

-Usually done by directing the cone mesially to avoid the thick bone distally

Root Canal Preparation

-Instrumentation.

-Debridement.

Objectives:

Removal of tissue inside the canal either necrotic or vital.

-Shape the canal to receive the filling (funnel shape).

Usually vital cases completed in one visit (because thee is no infection inside the canal and

the periapical area and its better to finish it in one visit)

Infected case usually completed in more than one visit.

Principles of root canal preparation:

-coronal preparation:

1-outline form

2-convience form

3-removal of

4-toilet of cavity

-Apical preparation:

retention form :



apical third of preparation (2-5mm) should be nearly parallel walls to ensure firm seating

of master cone Tug back)

resistance

retain of integrity of constriction of apical foramen.

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What Are We Trying to Achieve by Root Canal Treatment