• The pulp cavity is the central The pulp cavity is the central space within a tooth that enclosed space within a tooth that enclosed by dentin except at the apical by dentin except at the apical foramen. foramen.

• It is divided into a coronal It is divided into a coronal portion (the pulp chamber) and a portion (the pulp chamber) and a radicular portion (the root canal). radicular portion (the root canal).

• Other features include pulp Other features include pulp horns, canal orifices, accessory horns, canal orifices, accessory (lateral) canals, and apical (lateral) canals, and apical foramen. foramen.

Pulp HornsPulp Horns

Although pulp horns may vary in height and location, a single pulp horn tends to be associated with each cusp in a posterior tooth, and mesial and distal horns tend to be found in incisors.

Pulp horn may extends occlusally and exposure may occur as a result of caries or routine cavity preparation. Such abnormally high pulp horns may or may not be visible on radiographs.

Pulp ChamberPulp Chamber

The pulp chamber occupies the center of the crown and trunk of the root. Its shape depends on the shape of the crown and trunk; this configuration varies with tooth age or irritation.

Floor of pulp chamber

Roof of pulp chamber

Pulp Chamber

Pulp horn

Canal Orifice opening

Root canalsRoot canals

o Root canals extend from orifice to the apical foramen.

o Root canals vary according to root shape, size, degree of curvature, age, and condition of the tooth.

oThe shape of root canals mainly irregular, not straight and other variations in root canals may occur.

Accessory canalsAccessory canals

Accessory (or lateral) canals are branches of the main canal.

They contain connective tissue and may be located at any level from furcation to apex but tend to be more frequent in the apical third.

They contribute little to pulp function and probably represent an anomaly that occurred during root formation.

Apical RegionApical Region Root Apex: It is the root terminus that reflects maturation and is relatively straight in the young tooth but curves distally with time due to continued apical-distal apposition of cementum. Alterations in the apical region may result from resorption and irregular cementum apposition. Thus, apical anatomy tends to be nonuniform and unpredictable. Apical Foramen: It varies in size and configuration with maturity. It usually does not exit at the anatomic root apex but deviates an average of 0.5 mm of true apex. Apical foramen is not visible in the X-ray and the clinician must determine the extent of canal preparation and obturation (working length).

Apical Constriction

• Apical Constriction: The cementodentinal junction forms the apical constriction. The intra-canal extent of cementum is variable.

• Variations in Anatomy: The only consistent aspect of the apex region is its inconsistency. The canal may take twists and turns, divide into several canals to form a delta, or exhibit irregularities in the canal wall.

Types of rootsTypes of rootsType IMature straight roots (having closed apex with apical constriction)

Slightly Curved Severely Curved Dilacerated Bayonet

Type II

Mature but not straight root canals, which may be:

A. Tubular root apex

B. Blunderbus apex

Type IIIImmature (open apex) canals

)Straight or curved(

Types of Canal System

Type I: Single canal with single orifice and single apical foramen

Type II: Two canals with two orifices and single apical foramen

Type III: Two canals with two orifices and two apical foramen

Type IV: Single canal with single orifice and two apical foramina

Type V: A canal with a single orifice that divided into two canals and exit with a single apical foramen

Type VI: Single canal with two orifices and two apical foramen

Another Classification

Tooth demineralization and cross Section of teeth showing relationship between Pulp and external surface morphology

Anatomy of Pulp SystemAnatomy of Pulp System

Average Tooth Length: 23.3 ± 2.3 mmPulp chamber: wider MD Than Labio-palatal One root: One Root Canal (100%)

Straight, round, tapered, cylindrical Apical Distal curvature: (8%) Lateral root canals: OccasionalApical root canal delta: FrequentCross section: Ovoid/Ovoid/round

Maxillary Central Incisor

C.S

A

M

C

Maxillary Lateral Incisor

Average Tooth Length: 22.8 ± 2.3 mm Pulp chamber: wider Labio-palatal Than MD One root: one canal Apical distal curvature: (53 %)Lateral root canals: OccasionalApical root canal delta: Frequent Cross section Ovoid, Ovoid round

Average Tooth Length: 26 ± 3 mm Pulp chamber: wide LP than MD One Root: one canal Apical distal curvature: 32% Lateral root canals: InfrequentApical root canal delta: Occasional Cross section: Ovoid/Ovoid/Round

Maxillary Canine

ToothTotallength

Crown length

Rootlength

Number of roots

Types of canals

Maxillary central incisor

A = 23.0L = 28.0S = 18.0

10.512.08.0

12.516.08.0

One I

Maxillary lateral incisor

A = 22.5L = 27.0S = 17.0

9.010.58.0

16.516.58.0

One I

Maxillary canine

A = 27.0L = 32.0S = 20.0

9.512.08.0

16.520.511.0

One I

Tooth lengths, number of roots. and canal configuration for upper anterior teeth

A: average L: largest S: smallest

• Average Tooth Length: 21.5 ± 2 mm• Pulp Chamber: wide LL than MD• One Root One RC 70 % Two RCs with one Ap. For. 25% Two RCs with two Ap. For. 5%• Apical Distal Curvature: 23 % • Lateral root canals: Occasional• Apical root canal delta: Infrequent• Cross section: Ovoid/Round/Round

Mandibular Central Incisor

Mandibular

Lateral Incisor

Average Tooth Length: 22.5 ± 2 mm Pulp Chamber wide LL than MD One Root One RC > 55 % Two RCs with one ApF 30% Two RCs with two ApF 15% Lateral root canals: Occasional Apical root canal delta: Infrequent Apical Distal Curvature: 23 % Cross section Ovoid/Round/Round

Average Tooth Length: 25.5 ± 2.5 mm. Pulp Chamber Wide LL than MD (One Pulp Horn) One Root One canal (94 %), Two canal (6 %) Lateral root canals: Occasional Apical root canal delta: InfrequentApical Distal Curvature: 20 % Cross section Ovoid/Ovoid/Round

Mandibular Canine

Tooth lengths, number of roots. and canal configuration for lower anterior teeth

ToothTotallength

Crownlength

Rootlength

Number of roots Types of canals

Mandibular incisors

A = 21.0L = 25.0S = 16.0

9.010.57.0

12.014.59.0

One

I most frequent

II less frequent

III least frequent

Mandibular cuspid

A = 24.0L = 30.5S = 20.0

10.012.08.5

15.020.511.5

Two; one buccal and one

lingual (rare)

I most frequent

II less frequent

III least frequent

A: average L: largest S: smallest

Average Tooth Length: 22 ± 2.5 mm

Pulp Chamber: Wide LP than MD

Two Roots 72 %: 2 RCs (B&P)

One Root (22%): 2 RC (13 %),1 RC (9 %)

Three Roots: 3 RCs 6 % (2 B & 1 P)

Apical Distal Curvature: 37%

Lateral root canals: Infrequent

Apical root canal delta: Infrequent

Cross section: Ribbon/Ribbon/Oval

Maxillary First Premolar

Average Tooth Length: 21 ± 2 mm Pulp Chamber: Wide LP than MD Av One Root: (90%) 1 RC 75 %

2 RCs 15 % IIITwo Roots: 2 RCs 10% Apical Distal Curvature: 27%Bayonet Curv: 20%Lateral root canals: InfrequentApical root canal delta: InfrequentCross section: Ribbon/Ribbon/ Round

Maxillary Second Premolar

Typical tooth lengths. number of roots, and canal configuration for bicuspids

Tooth lengths. number of roots, and canal configuration for upper premolars

ToothTotal length

Crown length

Root length

Number of roots Types of canals

Maxillary first premolar

A = 21.0L = 24.0S = 17.5

8.510.07.0

12.514.510.0

Two, most frequent(60%), buccal and

palatalEach, 1

One (40%)

III most frequent

II less frequent

I rare

Three rare Each, I

Maxillary second premolar

A = 21.0L = 25.0S= 17.0

8.510.57.0

12.515.09.5

one (85%)

I most frequent

11 less frequent

III least frequent

may have Type IV

Two (15%), buccaland palatal

Each, I

Average Tooth Length: 22 ± 2 mm Pulp Chamber Wide LL than MD 1 Canal with 1 Foramen 73.5 % 2 Canals with 2 Foramina 19.5%

with 1 Foram … 6.5 % 3 Canals 0.5 % Apical Distal Curvature: 35% Lateral root canals: Occasional Apical root canal delta: Occasional RC Cross Section: Ribbon/Ribbon/

Round

Crown has Lingual inclinationCrown has Lingual inclination

Average Tooth Length: 22 ± 2 mm Pulp Chamber Wide LL than MD 1 Canal with 1 Foramen 73.5 % 2 Canals with 2 Foramina 19.5%

with 1 Foram … 6.5 % 3 Canals 0.5 % Apical Distal Curvature: 35% Lateral root canals: Occasional Apical root canal delta: Occasional RC Cross Section: Ribbon/Ribbon/

Round

Crown has Lingual inclinationCrown has Lingual inclination

Mandibular First Premolar

• Average Tooth Length: 21 ± 2 mm • Pulp Chamber: Wide LL than MD • One Canal 85 % • Two Canals with 2 F 14.5% • Three Canals 0.5 %• Apical Distal Curvature 4o % • Lateral root canals: Occasional• Apical root canal delta: Occasional• CrossSection:Ribbon/Ribbon/Round

Mandibular Second

Premolar

Tooth lengths. number of roots, and canal configuration for lower premolars

ToothTotal length

Crownlength

Root length

Number of roots Types of canals

Mandibular first bicuspid

A = 21.5L = 25.0S = 17.0

7.59.06.5

14.017.011.5

One See previous

Two, buccal andlingual

Each, I

Mandibular second bicuspid

A= 22.0L = 25.0S = 17.0

8.010.06.0

14.017.011.5

One

1 most frequent

11 or III rare

IV very rare

Two, buccal andlingual. very rare

Three, two buccals and one lingual

Each, I

Average Tooth Length: Buc roots : 20 ± 2 m Palat. root : 22 ± 3m

Three Rooted Tooth (MB, DB, PAL)

• 3 canals in 3 roots: 43 %• 4 Canals in 3 roots: 57 %

4th canal (MB2)

Maxillary First Molar

Buccal Apical Curvature ( PL root ) > 55 % Distal Apical Curvature ( MB root ) > 78%

Pulp Chamber: Triangular

Lateral root canals: Occasional

Apical root canal delta: Infrequent

Average Tooth Length: Buccal roots : 20 ± 2 m Palatal root : 21 ± 2m

Three Rooted Tooth: 44 % 63 % 3 Canals ( MB ,DB , PAL)

37 % 4 Canals 4th canal (MB2)

Two roots or ( fused ): 46 % (BC & PL (3 or 2 Canals)

Maxillary Second Molar

Buccal Apical Curvature ( PL root ) > 35 % Distal Apical Curvature ( MB root ) > 55%

Pulp Chamber: Triangular

Lateral root canals: Occasional

Apical root canal delta: Infrequent

ToothTotallength

Crownlength

Rootlength

Number of roots

Types of canals

Maxillary firstmolar

A= 20.5L=24.0S = 17.0

7.59.07.0

13.016.010.0

Three. two buccal andone palatal

Distobuccal and palatal: each I

Maxillary secondmolar

A = 20.0L=21.0S = 17.0

7.08.57.0

13.015.510.0

Three. two buccal andone palatal

(90%)

Distobuccal and palatal: each I.

Two. one buccal and

Each I most frequent; buccal root

Tooth Lengths, number of roots. and canal configuration for upper molars

• Average Tooth Length: 21 ± 2 mm• Roots are FLAT wider B-L

• 2 rooted tooth: (M & D).3 root canals: 70 %

M. Root 2 canals. D. Root 1 canal.

4 root canals: (30 %) (2 canals in Distal root)

Mandibular First Molar

•Apical Distal Curvature: (M root ) 85 %

• Pulp chamber: Triangular (Base Mesial, Apex distal)

• Lateral root canals: Occasional (furcation)

• Apical root canal delta: Frequent (Mesial root)

Average Tooth Length: 20 ± 2 mmRoots are FLAT wider BLM. root wider BL than D. root

2 rooted tooth: (M&D).3 root canals:70 % 4 root canals: 10 %.2 root canals: 20 %

Mandibular Second Molar

• Apical Distal Curvature M root: 60 %

• Pulp chamber Triangular (Base Mesial, Apex distal)

Lateral root canals: Occasional (furcation)

Apical root canal delta:

Frequent (Mesial root)

ToothTotallength

Crownlength

Rootlength

Number of roots Types of canals

Mandibular firstmolar

A = 21.0L = 24.5S = 18.0

7.510.06.0

13.515.011.5

Two, most common.mesial and distal

Mesial: 1II most frequent

II less frequentDistal: I most frequentII less frequentIII least frequent

Three. one mesial andtwo distal

Mesial: same as aboveDistal: distolingual very curved

Mandibular secondmolar

A = 20.0L = 24.0 S= 17.0

7.08.56.0

13.015.512.0

Two, most common.mesial and distal

Mesial: same as above Distal: I most frequent

II or ill rare

OneII most frequentI less frequentIII least frequent

Tooth Lengths, number of roots. and canal configuration for lower molars

The root canals of third molars are completely unpredictable because they are frequently short, tortuous, multiple & branching.

There is no patterns or rules to follow when treating this unpredictable tooth.

May have only one single canal.

Third Molars

MandibleMandible MaxillaMaxilla

PremolarsPremolars

Mo

lars

Mo

lars

Third molars can present problems, which are related to accessibility and anatomy.

Reaching the most posterior teeth with hand piece and hand instruments can be difficult because of poor visibility and restricted jaw opening.

Often these molars are tipped or mal-positioned.

• Dentin formation tends to occur in the roof and floor of the chamber pulp chamber are reduced in size, eventually making the chamber almost disc-like in configuration.• The orifices of the canals become smaller in diameter. • A pronounced curve in the canal might result from the newly formed secondary dentin.• A sharp curvature in the coronal area of the root canal might result from the secondary dentin formation.

Age Changes

• Anything that exposes dentin to the oral Anything that exposes dentin to the oral cavity can potentially stimulate increased cavity can potentially stimulate increased dentin formation at the base of tubules in dentin formation at the base of tubules in the underlying pulp. the underlying pulp.

• Vital pulp therapy such as pulpotomy, pulp Vital pulp therapy such as pulpotomy, pulp capping, or placement of irritating materials capping, or placement of irritating materials in a deep cavity may cause occlusion, in a deep cavity may cause occlusion, calcific metamorphosis, resorption, or other calcific metamorphosis, resorption, or other unusual configurations in the chamber or unusual configurations in the chamber or canals. canals.

Secondary dentin

Reparative dentin

Irritants

Pulp Stones• Although pulp stones are usually found in the Although pulp stones are usually found in the chamber and diffuse calcifications within the chamber and diffuse calcifications within the radicular pulp, the reverse may also occur. radicular pulp, the reverse may also occur.

• Stones in the chamber may reach Stones in the chamber may reach considerable size and can alter the internal considerable size and can alter the internal chamber anatomy. chamber anatomy.

• Chamber stones may be attached or free and Chamber stones may be attached or free and are usually removed during access preparation.are usually removed during access preparation.

• Pulp stones are NOT common in canals, they Pulp stones are NOT common in canals, they are usually attached or embedded in the canal are usually attached or embedded in the canal wall in the apical region. Rarely do they form a wall in the apical region. Rarely do they form a barrier to instrument passage.barrier to instrument passage.

Resorption

• Resorptions are less frequent than Resorptions are less frequent than dentindentin formation or calcifications and formation or calcifications and when present are usually not extensive. when present are usually not extensive.

• Resorptions are a response to irritation Resorptions are a response to irritation that is sufficient to cause inflammation. that is sufficient to cause inflammation.

• When visible radiographically, they are When visible radiographically, they are usually extensive and may create usually extensive and may create operative difficulties operative difficulties