WELCOME

GUIDED BY,DR. SMITA SINGH (MDS) (PROF. & H.O.D)

PRESENTED BY,DR. RAHUL AGRAWAL

1ST YEAR P.G. STUDENT

DANGER ZONE

“A REAL DANGER”???

INTRODUCTION

DANGER ZONE IS DEFINED AS AN AREA IN THE ROOT CANAL WALL THAT IS VULNERABLE TO EXCESS THINNING AND EVENTUALLY PERFORATION BY INJUDICIOUS FILING.

(ABOU-RASS et al.,1980)

DANGER ZONE ?? - Typical danger zone are at the mid

root level of the furcal wall of the root canal.

- Distal surface of the mesial root of mandibular molars.

- Distal surface of the mesiobuccal root of maxillary molars.

MANDIBULAR MOLAR MAXILLARY MOLAR

LINES INDICATING THE DANGER ZONE

. The UPPER PREMOLAR CREATES some special challenges due to narrow mesial-distal width.

. The root is only about half the width of the crown, creating the illusion of a tooth that is larger than it really is.

The lower LATERAL AND CENTRAL incisors teeth having a very narrow mesial-distal dimension .

. RIBBON SHAPED OR C-SHAPED CANALS:-

CONSEQUENCESSTRIPPING at the

danger zone is common consequence when treating this canals.

STRIPPING is the lateral perforation caused by over instrumentation through a thin wall in root .

CAUSES : -

Over zealous instrumentation in the mid-root areas .

Inability to use precurved instrument.

Inadequate knowledge of tooth Anatomy

DETECTION:-

- sudden appearance of haemorrhage in a previously dry canal from Pdl space.

- By a sudden complaint by

patient.

- Rinsing & blotting with cotton pellet , loupes, endoscope, radiographs, helps in visualising aids.

Dental literature studying the thickness of the dentin present in the danger and safety zones of molars is scarce.

Most agree that canal instrumentation becomes somewhat difficult since transportation of the canal always occurs towards those areas during preparation of the cervical third of the canal

DANGER ZONE & SAFETY ZONE

PREVENTION

knowledge of the Tooh morpholgy / Anatomy.

Pre-assesment with Radiographs

Use of pre-curved files for curved canals.

Use of modified files:- - File can be modified by removing flutes

of file at certain areas. - File portion which makes contact with:-

- outer dentinal wall at the apex - inner dentinal wall especially in

mid root area.

• Anticurvature Filing , a curve canal is progressively and directionally filed away from the danger zones.

• Cutting is carried out predominantly away from inner curve.

• Filing is done preferentially to mesial , buccal and lingual walls of the canals .

Progressive Crown-Down Preparation of the root canal using NiTi rotary instruments.

- Pre-enlargement of the coronal and mid-third aspect of the root canal system increases tactile control.

AET (ANATOMIC ENDODONTIC TECNIQUE)

- First description by Talbot (1880)

- Shaping instrument used in brushing-milling action against canal walls.

- Move the instrument from one side to another of the root canal, following its long axis.

- Make anti-curvature movements without forcing the tip of the instrument towards the apex, but firmly, with a brushstroke action against the desired lateral walls.

AET – PHASES & ARMAMENTARIUM

- The AET instruments, coherently with the Crown-down technique, have been designed with a stronger and sharper bulk in the upper half

- Which engages the coronal and middle thirds and is employed for their circumferential and anatomical enlargement.

- The rounded tip is not active and serves only for guidance of the instrument within the canal.

Management

- Internal repair (small perforation) A small area may be sealed from

inside the tooth.

- External repair (large perforation) A large one required surgical repair.

- Intentional reimplantation.

- Hemisection.

- MATERIALS FOR REPAIR:-

- MTA:-

PERFORATION

PLCEMENT OF COLLAGEN

PLACEMENT OF MTA

RESULT

- GERISTORE :-

- Hybrid ionomer composite.

- Bonds to all surfaces including: enamel, dentin, cementum.

- Provides excellent marginal integrity.

- Self-adhesive

CAVIT GIC

SUPER EBA IRM

- If the perforation is excessively large or long-standing, a full mucoperiosteal flap should be reflected.

- the perforation site identified, and the repair made with an appropriate repair material

Guided Tissue(Bone)Regeneration If the stripping perforation is

located apical to crestal bone the above crestal bone is removed.

In this cases effectiveness of the use calcium sulfate, alone OR along with composite with an allograft material, and resorbable and nonresorbable barrier membranes (GTR) can be used .

HEMISECTION

Intentional Reimplantation

Intentional removal (extraction) and replantation of a tooth.

This technique can be useful

for teeth that cannot be treated with traditional endodontic surgery.

This strategy can be particularly helpful in lower molars where proximity to the mandibular nerve and thickness of the buccal bone make endodontic surgery difficult.

PROGNOSIS - Prognosis must be considered to be

Reduced.

- Depends upon:- - time lapsed - size - location

- Surgical correction may be necessary if a lesion or symptoms develop.

CONCLUSION

. Having a sound understanding of the anatomy and the instrument systems and filing techniques being used will help the clinician avoid frustrating procedural errors in complex teeth.

. Such understanding will help the clinician to make the various judgments required in typical and atypical endodontic cases.

Refrences

DENTAL CLINICS OF NORTH AMERICA -VOLUME 41. NUMBER 3. JULY 1997.

American Journal of Public Health | August 2005, Vol 95, No. 8

International Endodontic Journal,38, 456–464, 2005.

Endodontic therapy – s.weine, 6th editionEndodontics-ingle 5th editionPathways of pulp - cohen

THANK U

HAVE A NICE DAY