Pulp Space Morphology PDF

Pulp Space Morphology Successful endodontic treatment depends mainly on proper diagnosis, thorough cleaning and shaping, and three-dimensional obturation. -Each tooth in the dental arch contains pulp tissue. The pulp is a connective tissue that is encased within a hard tooth structure, th...

Pulp Space Morphology Successful endodontic treatment depends mainly on proper diagnosis, thorough cleaning and shaping, and three-dimensional obturation. -Each tooth in the dental arch contains pulp tissue. The pulp is a connective tissue that is encased within a hard tooth structure, the dentin. -The pulp space is the central cavity within a tooth that is entirely enclosed by dentin except at the apical foramen. This space differs from one tooth to another and is subjected to numerous variations and anatomic complexities that have been demonstrated in the literature. -The clever clinician must always approach the tooth to be treated assuming all possible deviations and developing a 3-D image of its canal system. The pulp space is divided into: 1) Coronal pulp space: It is the space occupied by the pulp tissue within the crown. a- Pulp chamber: It is the pulp space that lies within the crown of the tooth. The shape of the pulp chamber usually reflects the external form of the crown. The size, on the other hand, may be reduced by aging and dentin deposition. b- Pulp horns: These are accentuations in the roof of the pulp chamber that lie directly below cusps. 2) Radicular pulp space: It is the space occupied by the pulp tissue within the root. a- Root canal: 1  It is the part of the pulp space that lies within the root of the tooth. It starts by an orifice and ends with an apical foramen. b- Accessory canals: These are lateral branches of the main root canal communicating the pulp space with the periodontium and ending with accessory foramina. Although they could exist at any level along the length of the root canal, they are mainly detected at the apical third of the canal as well as at the furcation area in multirooted teeth. -A distinction sometimes could be made between the lateral and the accessory canal in that the lateral canal is an accessory canal that branches to the lateral surface of the root and is visible on the radiograph. They could occur due to: The periodontal vessels at the apical third would curve around the root apex of a developing tooth and get entrapped within the epithelial root sheath of Hertwig. Breakdown of a segment of the epithelial root sheath of Hertwig before induction of dentin formation, hence inhibiting dentin or cementum formation.  The apical foramen: It is an aperture at or near the apex of the root through which the blood vessels and nerves of the pulp would enter or leave the pulp cavity. - Anatomical studies had demonstrated that the apical foramen could be located within the anatomical apex in only 17-46% of the cases. It could also exist on the mesial, distal, labial or lingual surfaces at an average of 0.4-0.7 mm away from the anatomical apex Fig. (1). 2  Fig. (1). Location of the apical foramen Root Canal Classes: Root canals can be classified according to maturity of the canals (completion of root canal formation) and curvature as follows Fig. (2): Class I: Mature, straight root canals Class II: Mature, curved root canals that could be: Slightly curved Severely curved Dilacerated Bayonet Slightly curved 3 Class III: Immature with open apex that could be: Tubular Blunderbuss Blunder bass Tubular Fig. (2) Root canal classes - Another classification has been developed by Weine to describe the different possible configurations of the root canal system within the single root Fig. (3) as follows: Types of Root Canal Configurations (Systems): Type I: Single root canal with one orifice and one apical foramen Type II: Two root canals with two orifices and one apical foramen Type III: Two root canals with two orifices and two apical foramina Type IV: Single root canal with one orifice and two apical foramina forming an apical delta. Type V: Single root canal with one orifice that divides into two canals within the body of the root forming a dentin island then reunite to exit with one apical foramen Type VI: Two root canals with two orifices that unite within the root into one canal then divide again at the apical third into two canals with two apical foramina. Fig. (3) Types of Root Canal Configurations 4  Type IV Type V Type VI PULP SPACE MORPHOLOGY OF ANTERIOR TEETH Maxillary Central Incisor: Fig. (4) - Average Length: 23mm - Root Number and Form: One and bulky - Canal Type: Type I -The chamber tapers towards the canal which in turn tapers uniformly to the apex. 5 - Outline form: Triangular in the middle one-third of the palatal surface with base incisally and apex cervically. Fig. (4) Maxillary Lateral Incisor: Fig. (5) - Average Length: 22.5mm - Root Number and Form: One slender root frequently with an apical distal and/or a palatal curvature. - Canal Type: Type I - Outline form: Triangular in the middle one-third of palatal surface 6. Fig. (5) Maxillary Canine: Fig. (6) - Average Length:26 mm; the longest root in the oral cavity. - Root Number and Form: One root, slender mesio-distally and bulky labio- lingually. Distal/ labial apical curvature may be present. - Canal Type: Type I Outline form: Oval inciso-gingivally in the middle third of the palatal surface. 7  Fig. (6) Mandibular Central and Lateral Incisor: Fig. (7) - Average Length:21 mm -Root Number and Form: One root that is narrow mesio-distally (M-D), but relatively broad labio-lingually (L-L). It has distal and /or lingual curvature. Sometimes two roots can be found; labial and lingual. - Canal Type: Type I 60%-70% 8 Type II, Type III 30%-40% - Outline form: Triangular in the middle third of the lingual surface, but sometimes could be oval due to aging. Fig. (7) Mandibular Canine: Fig. (8) -Average Length: 24mm -Root Number and Form: One root that is narrow mesiodistally, but broad labiolingually. -Canal Type: Type I 94% Type II, III 6% - Outline form: Oval labiolingually in the middle third of lingual surface. 9  Fig. (8) PULP SPACE MORPHOLOGY OF PREMOLARS Maxillary First Premolar: Fig. (9) -Average Length: 21mm -Root Number and Form: Two roots in 60% of the cases; buccal and palatal. One root in 38% of the cases Three roots in less than 2% of the cases; two buccal and one palatal 10 - Canal Type: -Two roots: Each has type I -One root: Type III most frequent -Three roots: Each has type I -Outline form: Oval in buccolingual dimension, in the center of the occlusal surface. Maxillary Second Premolar: Fig. (10) -Average Length: 21 mm -Root Number and Form: One root in 85% of the cases. Two roots in 15% of the cases Canal Type: One root: Type I most frequent Two roots: 11 Each has type I -Outline form: Oval buccolingual in the center of the occlusal surface. Fig. (9) Fig. (10 Mandibular First Premolar: Fig. (11) -Average Length: 22mm -Root Number and Form: One root. A relatively bulky crown in relation to the more slender root. Rarely two roots can exist; buccal and lingual. -Canal Type: One root: Type I most frequent 75% Two roots: One canal is present in each root (type I). 12 -Outline form: Ovoid buccolingually. The access cavity is located on the occlusal surface slightly towards the buccal cusp. Fig. (11) Mandibular Second Premolar: Fig. (12) -Average Length: 21.5mm -Root Number and Form: One root. Two roots can occur rarely: buccal and lingual. Three roots occur extremely rarely: two buccal and one lingual. -Canal Type: One root: Type I most frequent (85%) Type II, III, IV less frequent (15%) - Outline form: Ovoid buccolingually in the center of the occlusal surface. 13  Fig. (12) PULP SPACE MORPHOLOGY OF MOLARS Maxillary First Molar: Fig. (13) -Average Length: 20.5mm -Root Number and Form: Three roots, two buccal and one palatal. -Outline form: Triangular outline form, with base towards the buccal and the apex towards the lingual, reflecting the anatomy of the pulp chamber. Orifices are positioned at the angles of the triangle. The orifice of the MB canal is usually located under the MB 14 cusp tip, the DB orifice is 2 mm distal and palatal to the MB orifice, while the P orifice is usually found on the same straight-line palatal to the DB orifice. -In case of a fourth canal detected, second mesiobuccal canal (MB2), the outline form would be a quadrilateral where the extra orifice is detected in a groove palatal to the mesiobuccal canal (MB1) as a tail of a coma. -The cavity is entirely within the mesial half of the tooth and should be extended enough to allow positioning of the instruments and obturation techniques. A B Fig. (13) Mandibular First Molar: Fig. (14) -Average Length:21 mm 15 -Root Number and Form: Two roots, one mesial and one distal. -Outline form: Triangular outline form, with base towards the mesial and the apex towards the distal, reflecting the anatomy of the pulp chamber. Orifices are positioned at the angles of the triangle. The orifice of the MB canal is usually located under the MB cusp tip, the ML orifice is 2 mm lingual to the MB orifice, while the D orifice is usually located 1 mm distal to the central fossa. - In case of a fourth canal detected, DB or DL, the outline form would be a quadrilateral. -The cavity is entirely within the mesial 2/3 of the tooth and should be extended enough to allow positioning of the instruments and obturation techniques. Fig. (14) VARIATIONS IN THE INTERNAL ANATOMY OF TEETH Causes: a- Age b- Calcification c- Irritation d- Resorption 1.Variations in development i. Gemination 16  - A disturbance during odontogenesis in which partial cleavage of the tooth germ occurs and results in a tooth that has a double or “twin” crown ii. Fusion - A “double” tooth resulting from the union of two adjacent tooth germs. iii. Concrescence - Cemental fusion of two roots. 2. Variations in shape of pulp cavity i. C-shaped -This type of canal is usually found in mandibular molars. -Pulp chamber in C-shaped molar is single ribbon shaped with 180-degree arc or more. 3. Variations in size of tooth i. Microdontia ii. Macrodontia 17