1 YEAR M.Sc.D ENDODONTICS

MAXILLARY CENTRALMAXILLARY CENTRAL INCISORINCISOR

CONTENTSCONTENTS

ANATOMY OF TOOTH

MORPHOLOGY OF TOOTH

VARIATIONS OF TOOTH

ANOMALIES OF TOOTH

ENDODONTIC CORELATION

CENTRAL INCISOR

• The maxillary central incisor is a human tooth in the front maxilla, and is usually the most visible of all teeth in the mouth.

• their function is for shearing or cutting food during mastication .

• Instead, the surface area of the tooth used in eating is called an incisal ridge or incisal edge.

• Formation of these teeth begin at 14 weeks in utero for the deciduous set and 3–4 months of age for the permanent set.

INTRODUCTION

INTRODUCTION

• Human dentition is diphyodont• Primary (deciduous/ predecessor) dentition• Formula: I 2/2 C 1/1 M 2/2• Eruption: 6 months - 28±4 months• Shedding: 6 to12 years• Secondary (permanent/successor) dentition• Formula: I 2/2 C 1/1 P 2/2 M 3/3• Eruption: 6 to (18-25) years

Tooth anatomy

Labial Palatal Mesial distal

Average time of eruption: 7 to 8 yearsAverage age of calcification: 10 years

Average length: 22.5 mm

External anatomy• Conical and rapidly tapering toward the

apex, the root morphology is quite distinctive.

• Root is slightly triangular at the cervical aspect, gradually becoming round as it approaches the apical foramen.

• Multiple canals are rare, but accessory and lateral canals are common.

• Average length : 22.5mm

• greatest length :27mm

• Least length:18mm

Tooth length determination

• Labial aspect The widest MD of all incisors – type trait 3 mamelons Middle is the smallest in width Mesial has a raised shoulder Distal has a low shoulder 2 labial lobe grooves 90º mesioincisal line angle – type trait Rounded distoincisal line angle Mesial contour straight, distal is somewhat rounded and both converge cervically Mesial height of contour (contact point) within incisal third Distal HOC at junction between incisal & middle thirds CEJ convex cervical Root is conical & inclined distally

EXTERNAL FEATURESEXTERNAL FEATURES

EXTERNAL FEATURES• Lingual aspect• Scoop-like surface• Lingual fossa bordered by (all more prominent in

max.) * Mesial & distal marginal ridges• * Cingulum• CEJ more convex than labial& summit toward distal Root is narrower seen from lingual• Mesial aspect * Chisel-shaped * Labial HOC in the cervical third * CEJ curved incisally (the most pronounced) – type

trait * Incisal edge coincides with long axis * Root is conical

• Distal aspect * CEJ is less curved than seen from mesial

• Incisal aspect * Triangular outline * Labial outline is slightly convex Meets M+L outlines at sharp line angles

* Mesial outline is longer than distal * Labial lobe grooves

Arch traitsCrown

• Wider MD• Smaller height / width proportion• Greater MD / LL proportion

Root

• Greater MD / LL proportion• Conical root in central incisors

Type traits

• Size• Height / width proportion in crown• MD / LL proportion in crown and root

INTERNAL ANATOMYPULP CHAMBER

PULP HORN

ROOT CANALS

ACCESSORY CANALS

LATERAL CANALS

APICAL FORAMEN

Pulp chamber• Location centre of the crown• 3 pulp horns• Chamber ovoid mesio distally• Pulp chamber follows the contour • Broad mesiodistally- broadest part incisally• There is no distinct division between root canal and pulp chamber

ROOT CANAL

• 1 root and one root canal• Conical in shape• Lateral canal in the apical third • Majority canals are straight (75%)• Distally (8%)• Palatally(4%)• Mesially(4%)• Labally(9%)

Root canal

Root canal of central incisor

Root canal system

Single root canal system

Schilder –collateral circulation- portal of exit –Steriomicroscopic study of root apices –av major foramen 0.4mm,

Accessory foramina-0.2mm12% showed accessory canals

Root canals & apical foramen were displaced distolabially

Lateral canals were found half of specimens

VERTUCCIS CLASSIFICATION OF ROOT CANAL SYSTEM

SERT AND BAYIRILS ADDITIONAL CANAL TYPES TO VERTUCCS CLASSIFICATION OF ROOT CANAL

CLASSIFFICATION AND PERCENTAGE OF ROOT CANALS IN THE MAXILLARY TEETH

MAXILLARY CENTRAL MAXILLARY CENTRAL INCISORINCISOR

NO OF TEETHNO OF TEETH

TYPE 1TYPE 1 100100

TYPE 11 (2-1)TYPE 11 (2-1) OO

TYPE III (1-2-1)TYPE III (1-2-1) 00

TOOTH WITH ONE CANAL AT TOOTH WITH ONE CANAL AT APEXAPEX

100100

TYPE IV 2CANALSTYPE IV 2CANALS OO

TYPE V(1-2)TYPE V(1-2) 00

TYPE VI(1-2-1)TYPE VI(1-2-1) 00

TYPE VII(1-2-1-2)TYPE VII(1-2-1-2) 00

TOTAL WITH 2 CANALS AT TOTAL WITH 2 CANALS AT APEXAPEX

00

TOOTH WITH 2 CANALS AT TOOTH WITH 2 CANALS AT APEXAPEX

00

TYPE VIIITYPE VIII 00

TOTAL WITH 3 CANAL AT TOTAL WITH 3 CANAL AT APEXAPEX

00

• 60% of specimen shows accessory canals

• 45% of specimen shows apical foramen apart from apex

73.5 % -- APICAL 3 OF ROOT

11.5 % -- MIDDLE 3 OF ROOT

15.1 % -- CERVICAL 3 OF ROOT

ACCESSORY CANALS

Anatomic relationships in situ

• lies close to the close labial cortical plate• More prone to fenestration,

dehiscence, abscesses.• Mesioaxial angulations -2 degree• Palatoaxial angulation-29 degree• Incisive canal parallels the long axis of

central incisor

Variations and anomalies Shovel shaped incisors are common in Asian population Incidence of radicular grooves -0.9%

Gemination and fusion

Highest incidence of gemination and fusion

Maxillary incisor with two roots very rare

Combination of anomalies were found-talon cusp, short roots, Dens invaginatus

Solitary median maxillary central incisors

• Multiple midline defects• Unknown etiology• Defers from normal central incisors• Found in the midline of maxillary arch• Aesthetic problem • Associated with cleft lip and cleft palate, heart

disorders ,congenital heart diseases,hypotelorism,hypopitutarism

Hutchinson's syndrome

• Mainly affects incisors• Hutchinson's teeth-congenital syphilis-notch

to form on the incisal edges of the teeth.• Screw driver shaped teeth-Hutchinson's teeth

Hutchinsons incisors keratitis 8 nerve deafness

Hutchinson's syndromeHutchinson's syndrome

Spacing between the tooth –diastema

Between the contacts of the maxillary central incisors

Mainly due to the high frenal attachment

Treatment is frenectomy followed by the ortodontic treatment

DIASTEMA

Talon cusp• Talon cusp is usually defined as an accessory cusp like structure resembling an eagle’s talon in shape.• It projects incisally from the Cingulum area of the incisors

and consists of enamel, dentin and pulpal tissue• The pulp chamber in some cases follows the morphological

variation of the tooth crown • Gorlin and Goodman defined talon cusp as a high accessory

cusp reaching the incisal edge to produce a T-form or a Y-shaped tooth crown.

• The conventional definition of talon cusp was considered only an accessory cusp projecting incisally from the cingulum area of an incisor.

• The current definition of talon cusp includes accessory cusp on the lingual or labial aspect of incisors or canines.

Talon cusp

Labial talon cusp on the maxillary left central incisor.The cusp extended from the cervical region to the incisal edge.

Labial talon cusp on the maxillary left central incisor.The cusp extended from the cervical region to the incisal edge.

Talon cuspTalon cusp

Bifid cingulum

DENTAL ANOMALIES11 and 21 Shovel-shaped,

TEETHTEETH MESIODISTAL MESIODISTAL mmmm

LABIOLINGUALLABIOLINGUALmmmm

VERTICAL mmVERTICAL mm

CENTRAL CENTRAL INCISORINCISOR

0.37 0.37 0.4280.428 0.8630.863

MEAN PERPENDICULAR DISTANCE FROM ROOT APEXTO APICAL CONSTRICTION WITH MESIO DISTAL AND LABIO LINGUAL DIAMETERS AT CONSTRICTION

SIZE OF APICAL FORMINA

TEETHTEETH MEAN VALUEMEAN VALUE

MAX- INCISORMAX- INCISOR 289.4 U289.4 U

MEDIAN CANAL DIAMETER IN mm AT 1,2,5 mm FROM APEX

ENDODONTIC CORELATION

The lingual view shows the incisally repositioned access with the rotary notch. From the lateral view, the darker wedge-shaped portion of the access shows how incisally this notch may be placed. With the repositioned access, very little cervical dentin needs to be removed

ACCESS CONSIDERATIONS

ACCESS SHAPE

ACCESS CONSIDERATIONS

ERRORS IN CLEANING AND SHAPING

PRECURVING THE FILES

precurving the files and using balance force technique will preventledge formation

ACCESS OPENING CONSIDERATIONS

Rotary notch in the access opening .this notch allows more straight Line access and prevents instrument breakage

Residual pulp horn, immature pulp should be removed

references• INGLE – ENDODONTICS 6 EDITION• COHEN PATHWAYS OF PULP 9 EDITION• WOLFES DENTAL ANATOMY• GROSSMAN -11 EDITION• COLOUR ATLAS OF ENDODONTICS- WILLIAM .T.JOHNSON.• WWW.WIKIPEDIA.COM• JOURNAL OF ORAL SCIENCE VOL45,47-50,2003• BRITISH DENTAL JOURNAL SHAFER ORAL PATHOLOGYTHE ON LINE ANGLE ORTHONTIST, VOL77-NO.1,PP176-180WWW.BIBLIOTECA.UNIVERSIA.NET

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