9Dental Anatomy b. Dentin (1) Makes up bulk of tooth. (2) Covered by enamel on crown and cementum on the root.(3) Not as hard as enamel.(4) Exposed dentin is often sensitive to cold, hot, air, and touch (via dentinal tubules).
11Dental Anatomy c. Cementum (1) Covers root of tooth. (2) Overlies the dentin and joins the enamel at the cemento-enamel junction (CEJ).(3) Primary function is to anchor the tooth to the bony socket with attachment fibers.
15Dental Anatomy 4. Periodontium a. Alveolar process. (1) Bone extensions of the maxillae and mandible that supports the teeth.(2) Cortical plate is the dense outer layer of bone covering the spongy (cancellous) bone
16DentinEnamelDentinal TubulesCementumPulpAlveolar ProcessCortical PlateSpongy Bone
17Dental Anatomy b. Periodontal ligaments. Dense connective fibrous tissues that connect teeth to the alveolar bone.One end is embedded in cementum and other end in bone.Supports and protects the tooth from normal shock.
21Odontogenesis Bud Stage Cap Stage Bell Stage D and E. Dentinogenesis andamelogenesisCrown formationRoot FormationEruption
22A. Bud StageIntramembranousossificationMeckel’scartilageBud stage is characterized by rounded, localized growth of epithelium surrounded by proliferating mesenchymal cells, which are packed closely beneath and around the epithelial buds
23B. Cap StageVestibular laminaWhen the appropriate depth is reached, the basal layer at the tip of the dental lamina thickens, forming a concavity.
24C. Bell StageDental laminaOuter dentalepitheliumInner dentalepitheliumDental papillaDental follicleCervical loopContinued growth leads to bell stage, where the enamel organ resembles abell with deepening of the epithelium over the dental papillaContinuation of histodifferentiation (Inner dental epithelium - ameloblasts andDental papilla - odontoblasts)
25D. AmelogenesisAmeloblastsFirst layer of enamelDentinOdontoblastsAt the same time or soon after the first layer of dentin (mantle dentin) is formed,the inner dental epithelial cells differentiate into ameloblasts and secrete enamelproteins.The ameloblasts will then start laying down organic matrix ofenamel against the newly formed dentinal surface. The enamel matrix willmineralize immediately and form the first layer of enamel. The formation ofenamel is called amelogenesis.
26E. DentinogenesisDentin is formed by odontoblasts that differentiate from ectomesenchymal cells of dental papilla with influence from the inner dental epitheliumDifferentiation of odontoblasts is mediated by expression of signaling molecules and growth factors in the inner dental epithelial cells
27F. Crown FormationGrowth areas of developing crown. Growth at cusp tip, intercuspal region, and cervical regionIncremental pattern of dentin and enamel formation from initiation to completion
28G. Root FormationHertwig’s epithelialroot sheathDevelopment of root begins after the enamel and dentin formation has reached the future cementoenamel junctionEpithelial cells of the inner and outer dental epithelium proliferate from the cervical loop of the enamel organ to form the Hertwig’s epithelial root sheath. The root sheath determines if a tooth has single or multiple roots, is short or long, or is curved ir straight
29Epithelial Cell Rests of Malassez Inner dental epitheliumOuter dental epitheliumHertwig’s epithelialroot sheathStratum intermediumEventually the root sheath will fragment to form several discrete clustersof epithelial cells known as epithelial cell rests of malassez. These will persist in adults within the periodontal ligamentThe epithelial rests appear as small clusters of epithelial cells which are located in the periodontal ligament adjacent to the surface of cementum. They are cellular residues of the embryonic structure known as Hertwig's epithelial root sheath.
30H. Tooth Eruption and Development of supporting structures Soon after root formation begins, tooth begins to erupt until it reaches its final positionWhile roots are forming, the supporting structures of tooth also develop – periodontal ligament and cementumAs the root sheath fragments, the dental follicle cells will penetrate between the epithelial cells and lie close to the newly formed root dentinThese cells will differentiate into cementoblasts, which will make cementum
31REVIEW: Odontogenesis Bud StageCap StageBell StageD and E. Dentinogenesis andamelogenesisCrown formationRoot FormationEruption
32Types of Dentition 1. Deciduous (baby) teeth a. Twenty ( 20) primary teeth.b. Arches - maxillary and mandibular.c. Quadrants - each arch divided in half.(1) Maxillary right and left.(2) Mandibular right and left.Enamel is thinner, pulp is thicker
33Deciduous Teeth d. Teeth in each quadrant. (1) Central incisor (2) Lateral incisor(3) Cuspid(4) 1st molar(5) 2nd molar
34Deciduous Teeth f. Numbering system. (1) Alphabetical. (2) Maxillary - patient’s right to left, “A” through “J”.(3) Mandibular - patient’s left to right, “K” thru “T”.KLMNOPQRSTABCDFHIJEGMAXILLARYMANDIBULAR
39Tooth Surfaces 1. Facial - next to cheeks & lips. a. Labial- anterior facial.b. Buccal - posterior facial.Lingual- next to tongue.Mesial - towards midline, an imaginary line between central incisors.Distal- away from midline.Incisal- cutting edge of anterior teeth.Occlusal- chewing surface of the posterior teeth.
40Tooth Surfaces7. Proximal surfaces mesial or distal surface of a tooth lying next to another tooth.8. Interproximal space(embrasure) - spaces between teeth, filled with hard and soft tissue (interdental papilla).
41Tooth Surfaces9. Cusps- pronounced elevations on the occlusal surfaces of a tooth terminating in a conical or rounded surface.