MANAGEMENT OF CURVED ROOT CANAL SYSTEMS MISSION IMPOSSIBLE? DR TOM JM DIENYA BDS(NBI), CIBRD(KASADA), MDSc-Endo(Mal), Cert. In Oral Implantology (Mal) SPECIALIST ENDODONTIST,IMPLANT PRACTITIONER AND LECTURER Dept of Conservative Dentistry University of Nairobi Practice limited to Endodontics and implantology E-Mail: tomdienya@uonbi.ac.ke or tomdienya@yahoo.com

Introduction and Lit review The goal of endodontic therapy is the prevention and/or elimination of pathosis of endodontic origin Correct diagnosis SUCCESFULL RCT Cleaning and Debridement Complete obturation (European Society of Endodontology Consensus, 1994, Omer et al., 2004, , FDI World Dental Press, 2005 ).

Introduction and Lit Review cont.. Inadequate understanding Of Root Canal Systems Detailed Knowledge of ROOT CANAL SYSTEM Improper shaping And Inadequate Cleaning SUCCESSFUL ROOT CANAL Poor Obturation Treatment Failure Omer et al.,2004,Mikrogeorgis et al.,1999,Al-Nazhan,2007 Carrotte,2004

INTRODUCTION CONT.. A tooth with a straight root and a straight root canal is an exception rather than being normal because most teeth show some curvature of the canal (weinne,scheinder,kyomin). Tomes, in 1848, called such curvatures as dilacerations

Dilaceration: Defination It refers to an angulation or a bend or a curve in the root or crown of formed tooth or a deviation or in the linear relationship of a crown of a tooth to its root.

Epidemiology In most studies,prevalence of curvature ranged between 80 to 100%. Dienya et al 2009 in a study of 400 maxillary and mandibular 1st molars in a Kenyan population got 91% curvature. Dr Schaffer in Germany examined 1163 root canals and found that 980 (84%) were curved and 65% showed an angle > 27 degrees with radii < 40 mm.

CAUSE The condition is thought to be due to trauma during the period in which tooth is forming. The result is that the position of the calcified portion of the tooth is changed and the remainder of the tooth is formed at an angle

Types of curvatures Curved canals can be: Gradual curvature of the canals in the coronal,middle or apical third; Acute curvature in the apical third; Curvature throughout the canal; S-shaped root canal.

Mandibular 1st molar with GRADUAL distal curvature of the mesial root

Maxillary molar with the DB root showing ACUTE curvature in the apical third

Buccal curvature at the tip of a palatal root

Mandibular 1st molar with an S-curvature of the D root

Combination of S-shaped canals and gradual shape

THE STAIR CASE CURVE

THE DECEIVING CURVE ---distal root curves lingually

THE CONSEQUENCES EXCESSIVE FLARING LEDGING APICAL TRANSPORTATION APICAL PERFORATION

SHORT OBTURATION- due to inability to negotiate curvature

Instruments break unexpectedly Separated apical part Common to all curvatures: Instruments break unexpectedly Separated apical part is difficult to remove A Major Drawback !

Instruments separation just at the beginning of the curve

Missed canal in maxillary 1st molars Note : Canal was missed probably due to it being hidden at the beginning of the curve presence of lamina dura—indicates canal presence

pain

Management Start with accurate diagnosis preoperative radiographs taken with parallelling technique with at least two different views-SLOB RULE: UPPER TEETH-normal buccal view,then use rule MMMM LOWER TEETH—normal buccal view then use the rule DMMD or use CBCT OR DIGITAL X-RAYS

Paralleling technique in the lower jaw

Parallel periapicals

Root canal configurations obtained with CBCT Type IV Type III Type II Type I Additional canal 2 Additional Canal 3 Additional Canals 1 Type VI Type V

Make a good access cavity

Pitfalls of inadequate access Remnants of pulp roof removed by slow speed round bur Straight line access achieved Inadequate acess easily leads to ledging

Determine the DEGREE OF curvature Before initiation of treatment, an estimate should be made as to the degree of curvature of canals by seeing the radiograph, probing OR schneiders method The interior angle is formed by intersection of the straight line from the orifice through coronal portion of the root and another straight line from apex through apical portion of canal

Take an impression of the canal S-shaped c-shaped J--shaped Merging canals

USE CROWN DOWN TECHNIQUE

Divide the root into three

Flare coronal one third and open up orifice-use orifice shapers Or 25/07 in mtwo system or sx in protaper system—Do not use gates glidden.

ENDOFLARE 2 ENDOFLARE® filing (penetration < coronal third) 1 Before ENDOFLARE® filing - Pronounced dentinal overhang 3 After ENDOFLARE® filing - Elimination of the coronal strains

BEFORE AFTER Pr. CALAS

Working length

Working length-practical determination Use apex locators—such as raypex 6 or vdw

motor

No direct measurements on file Direct measurements are likely to introduce errors

MEASURE CURVATURE by tracing

rules R>160------stainless steel handfiles can be used R—140—160---consider precurving stainless steel files or use rotary R –100—140—rotary with initial glide path;use highly flexible files with radial lands or use rotary in straight portion and hand files apically R –90—100—niti hand files with high flexibility; orifice shapers only coronally R—90 or less—consider apicoectomy and reverse filling,aggressive use of hand niti

management USE OF HAND NITI FILES Tedious..some files can break due to torsional stress

PRECURVING STAINLESS STEEL FILES

Crown Down Technique

Crown Down Technique Coronal third Orifice shapers Middle third 0.06 taper rotary Apical third 0.04 OR 0.02 taper hand or rotary

FILES TO USE

HERO Shapers Red sequence

Red sequence for average difficult cases 25 6% 25 4% 30 4% + + 2/3 WL WL WL 2/3 WL WL

HERO Shaper Yellow sequence

HERO Shaper Yellow sequence

Yellow sequence for difficult cases 20 6% 20 4% 25 4% 30 4% + + + 2/3 WL WL WL WL 2/3 WL WL

Preparation of coronal third

Preparation of middle third

Preparation of the apical third Prepare to actual working length Use 0.04 taper NiTi hand files in sequence smaller to larger

Preparation of apical third

Irrigation needle should have side opening to opening to preven driping of irrigant fluid hence pain

Acoustic streaming around a file in free water (left) and a schematic drawing (right).

cases

Extensive Amalgams-can be very painful necessitating endo-therapy

Single cone technique????

THANK YOU SO MUCH FOR YOUR ATTENTION