Overview of Dentitions
•Download as PPTX, PDF•
0 likes•2,061 views
The document summarizes dental anatomy and dentition development. It describes the primary dentition which consists of 20 teeth that erupt between 6 months and 2.5 years of age. Between 6-12 years is the mixed dentition period where both primary and permanent teeth are present. The permanent dentition period begins around 12 years of age when all 32 permanent teeth have erupted, excluding third molars. The document also outlines tooth structures like the crown, root, and pulp as well as dental terminology.
More Related Content
What's hot
What's hot (20)
Similar to Overview of Dentitions
Similar to Overview of Dentitions (20)
Recently uploaded
Recently uploaded (20)
Overview of Dentitions
- 1. Jacey Mitchell, RDH, MS
- 2. The first dentition is the primary dentition.
- 5. The permanent dentition is the second dentition to develop.
- 6. 8- Incisors 4- Canines 8- Premolars 12- Molars
- 9. Canines
- 13. Begins with the eruption of the primary mandibular central incisors Occurs between 6 months and 6 years Only primary teeth are present during this period All 20 teeth are fully erupted around 30 months
- 14. The mixed dentition period follows the primary dentition period. This period occurs between approximately 6 and 12 years of age. Both primary and permanent teeth are present during this transitional stage. Shedding of primary teeth and eruption of permanent teeth occurs
- 15. Permanent Dentition Period The final dentition period is the permanent dentition period. This period begins with shedding of the last primary tooth. Thus, this dentition period usually begins just after 12 years of age. Included is the eruption of all the permanent teeth, except for teeth that are congenitally missing or impacted and cannot erupt, usually involving the third molars.
- 18. The incisors and canines are considered anterior teeth because they are closer to the midline. In contrast, the molars (and premolars, if present) are considered posterior teeth because they are farther from the midline.
- 19. Crown Root Enamel Dentin Cementum Pulp Pulp Chamber Pulp Canal(s) Apical Foramen Pulp Horn(s)
- 21. The large mass of pulp is contained within the pulp chamber of the tooth. The shape of each pulp chamber corresponds directly to the overall shape of the tooth and thus is individualized for every tooth. The pulp tissue in the pulp chamber has two main divisions: coronal pulp and radicular pulp. 21
- 22. All the teeth are attached to the bony surface of the alveoli by the fibrous periodontal ligament (PDL), which allows some slight tooth movement within the alveolus while still supporting the tooth.
- 25. TOOTH ANATOMY
- 26. Each tooth has 5 surfaces Some of the surfaces of the tooth are identified by the orientational relationship to other orofacial structures, similar to the designation of the soft tissue of the oral cavity
- 27. Facial • Labial • Bucca Lingual • Palatal Mesial Distal Masticatory Surface • Occlusal • Incisal
- 28. A crown surface can be divided both horizontally and vertically into three parts called “thirds” A root can be divided into thirds only horizontally
- 30. Cusp- major elevations on the masticatory surface of canines and posterior teeth Ridges- linear elevations on the masticatory surface of both anterior and posterior teeth
- 31. Proximal Interproximal Space Contact Area
- 33. When two teeth in the same arch come into contact, the curvatures next to the contact areas form spaces considered embrasures.
- 34. line angle
- 35. point angle
- 37. • Numbered 1-32 • #1- maxillary right 3rd molar • #32- mandibular right 3rd molar • Clockwise Permanent Dentition • Capital letters A-T • A- maxillary right 2nd molar • T- mandibular right 2nd molar • Clockwise Primary Dentition
- 40. International Standards Organization (ISO) Almost never used Teeth are designated using a 2 digit code First digit- indicates the quadrant Second digit- indicates the tooth Based on FDI system Palmer Method Widely used in orthodontics Teeth are designated with a right-angle symbol indicating the quads with the tooth number inside Similar to ISO
Editor's Notes
- Child patients and their supervising adults consider the primary teeth to be the baby teeth. An older term for the primary dentition is the deciduous dentition. This term is derived from the concept that the primary dentition is shed (just as deciduous trees shed leaves) and replaced entirely by the permanent dentition. Teeth comprise around 20% of the surface area of the oral cavity—maxillary more so than mandibular teeth.
- Also considered normal in most child patients are certain interproximal spaces between the primary teeth because space is necessary for the proper alignment of the future permanent dentition. These spaces are considered primate spaces (arrows), mainly involving spaces between the primary maxillary lateral incisor and canine, and also between the primary mandibular canine and first molar.
- Teeth comprise around 20% of the surface area of the oral cavity, maxillary more so than mandibular teeth.
- Thus, the permanent dentition is the second dentition to develop. The permanent dentition is also sometimes considered the secondary dentition, and the permanent teeth are called the adult teeth. By recent convention (or convenience), clinicians seem to prefer to mix and match terms when referring to the two dentitions, as in primary dentition and permanent dentition.
- Note that only the permanent dentition has premolars; in contrast, the primary dentition does not have premolars.
- Although there are only two dentitions, there are three dentition periods throughout a person’s lifetime because the two dentitions overlap in time: primary, mixed, and permanent. Each patient should be assigned a dentition period to allow for the most effective dental treatment for that period.
- The jaws are beginning to also grow further during this period to accommodate the coming larger and more numerous permanent teeth. This period usually ends when the first permanent tooth erupts—the permanent mandibular first molar.
- Thus, this period begins with eruption of the first permanent tooth, a permanent mandibular first molar, which is guided by the distal surface of the primary second molar. This period usually ends with shedding of the last primary tooth, which generally occurs from age 11 to 12. The color differences between the primary and permanent teeth become apparent during this middle phase, as any supervising adult has noticed in the child and routinely and enviously points it out to the dental professionals. The primary crowns are lighter in color than the darker permanent crowns owing to the fact that the permanent teeth having less opaque enamel, and thus the underlying yellow dentin is more visible. Also more evident is the difference in the crown size and root length between the smaller and shorter primary teeth and the larger and longer permanent teeth.
- The permanent teeth are usually the only teeth present during this period. Growth of the jaws is not as noticeable because it slows and then eventually stops. Thus, little growth of the jaws occurs overall during this period, given that puberty has passed. Tooth types tend to erupt in pairs so that, if any asymmetry exists in a patient, a radiograph of the area may be required. When a child patient is unusually early or late regarding the usual sequential eruption of teeth, the biologic family dental history should be reviewed for developmental anomalies.
- Each dental arch has a midline, an imaginary vertical plane that divides the arch into two approximately equal halves—a right and a left. Half vs Quadrant vs Sextant sextant (sex‑tant) An example is that the permanent maxillary right central incisor is in the maxillary anterior sextant of the permanent dentition. This division follows the mapping of oral nerve pathways, especially in the maxillary arch. Thus, the use of sextants can be useful in dental treatment plans for regions, such as those that use local anesthesia for patient pain control like periodontal therapy.
- Teeth can also be described according to the position in each dental arch and in relationship to the midline. The illustrations of the head and neck, as well as any structures related to them, are oriented according to the patient’s head being in anatomic position unless otherwise noted. This is the same as if the patient were being viewed straight on while sitting upright in the dental chair. Thus, maxillary teeth show the root superior to the crown; mandibular teeth show the root inferior to the crown. Orientation of the dental chart is traditionally from the dental professional’s view (i.e., the patient’s right corresponds to the notation chart’s left). The designations "left" and "right" on the chart, however, nonetheless correspond to the patient’s left and right, respectively. Other dental charts may show each of the teeth "unfolded" so that the facial, occlusal or incisal, and lingual surfaces of the teeth can be noted.
- Each tooth consists of a crown and one or more roots. The crown has dentin covered by enamel, and each root has dentin covered by cementum. The inner part of the dentin of both crown and root also covers the pulp cavity of the tooth. The pulp cavity has a pulp chamber, pulp canal (or canals) with an apical foramen (or foramina), and possibly a pulp horn (or horns). The crown of the tooth is composed of the extremely hard outer enamel layer and the moderately hard inner dentin layer overlying the pulp of the tooth. A, Gross specimen of tooth cross-sectioned. B, Radiograph of tooth. The pulp is the soft innermost layer in the tooth. The moderately hard dentin continues to cover the soft tissue of the pulp of the tooth in the root(s).
- The moderately hard dentin continues to cover the soft tissue of the pulp of the tooth in the root(s), but the outermost layer of the root(s) is composed of cementum. cementum (see-men-tum) Diagram of an alveolar process of both a single-rooted tooth and a multirooted tooth showing the crown and root as well as associated tissue types. The bonelike cementum is the part of the tooth that attaches to the periodontal ligament, which then attaches to the alveoli of bone, holding the tooth in its socket or alveolus. The enamel of the crown and cementum of the root usually meet close to the cementoenamel junction (CEJ), an external line at the neck or cervix of the tooth. There are three possible interfaces at the CEJ, and multiple situations are possible on one tooth or even one surface of the tooth. At the CEJ, the cementum over the neck of each tooth may overlap the enamel, the enamel may meet the cementum edge to edge, or a small area of underlying dentin may be exposed because there is a gap between the enamel and cementum. The CEJ usually feels smooth or evenly grainy or has a slight groove when explored.
- The coronal pulp is located in the crown of the tooth. Smaller extensions of coronal pulp into the cusps of posterior teeth form the pulp horns. The radicular pulp, or root pulp, is the part of the pulp located in the root of the tooth; it is also called the pulp canal by patients. The radicular pulp extends from the cervical part of the tooth to the apex of the tooth. This part of the pulp has openings from the pulp through the cementum into the surrounding periodontal ligament (PDL). These openings include each apical foramen and possibly accessory canals.
- periodontal (pare-ee-o-don-tl) ligament (PDL) The PDL is that part of the periodontium that provides for the attachment of the teeth to the surrounding alveolar bone proper (ABP) by way of the root cementum.
- Each tooth is surrounded and supported by the bone of the tooth socket, or alveolus (plural, alveoli). Each alveolus is located in the alveolar process, or tooth‑bearing part of each jaw. Each alveolar process of the jaws is also considered a dental arch—either the maxillary arch or mandibular arch. Anatomy of alveolar process on skull. A, Mandibular arch with the permanent teeth removed. B, Part of the maxilla with the teeth removed demonstrating the surrounding cribriform plate of the alveolar bone proper of the alveolus. C, Cross section of the mandible with the teeth removed and a mandibular molar alveolus highlighted (dashed lines).
- The anatomic crown is the part covered by enamel. It remains mostly constant throughout the life of the tooth, except for attrition and other physical wear. The clinical crown is that part of the anatomic crown that is visible and not covered by the gingiva. Its height is determined by the location of the marginal gingiva. The clinical crown of a tooth can change over time, especially with gingival recession as the marginal gingiva recedes toward the root. Clinical view of gingival recession exposing root dentin. Note the difference in color between the whiter enamel and the more yellowish dentin, which has also undergone additional staining of the root surfaces due to exposure.
- Similarly, the anatomic root is that part of the root covered by cementum. The clinical root of a tooth is that part of the anatomic root that is not visible. It is embedded in the jaws and NOT seen. When discussing the root of a tooth, it usually refers to the anatomic root of a healthy tooth unless designated otherwise.
- Note that in reference to line angles, point angles, thirds, or even a direction, there is an accepted sequencing of combined names of the involved surfaces. The accepted sequence allows that the term mesial precedes the term distal and also that both mesial and distal precede all other terms. The terms labial, buccal, and lingual follow mesial or distal but precede incisal or occlusal in any combination.
- An example is the middle third of the labial surface of an anterior tooth’s crown. However, the root can be divided into thirds only horizontally. An example of designating a third area on a tooth root is the cervical third of the buccal surface of a posterior tooth’s root. In comparison, the root is can only be divided vertically into halves by the RAL as discussed earlier, such that the halves when viewing the tooth from the mesial or distal are designated as labial or buccal and lingual; the halves when viewing the tooth from the labial or buccal are designated as mesial and distal.
- Maxillary and mandibular canines both have one cusp, and the maxillary premolars and the mandibular first premolars usually have two cusps. Mandibular second premolars frequently have three cusps: one buccal and two lingual. Maxillary molars have two buccal cusps and two lingual cusps; a minor fifth cusp may form on these teeth (cusp of Carabelli). In contrast, mandibular molars may have five or four cusps.
- Together, both the mesial and the distal surfaces between adjacent teeth are considered the proximal. In other words, either surface of a tooth that is next to an adjacent tooth is referred to as a proximal surface, which may therefore be either the mesial or the distal surface. The area between adjacent tooth surfaces is the interproximal space. The area where the crowns of adjacent teeth in the same arch physically touch on each proximal surface is the contact area, or, as referred to by clinicians, the contact.
- The contact areas on the mesial and distal are usually also considered the location of the height of contour on the proximal surfaces. The height of contour, or crest of curvature, is the greatest elevation of the tooth either incisocervically or occlusocervically on a specific surface of the crown when viewing its profile from the labial or buccal and the lingual. The crown also has a facial or lingual height of contour that is easily seen when viewing the crown’s profile from the mesial and the distal. The facial and lingual surfaces of a tooth also have a height of contour that is easily seen when viewing the tooth’s profile from the proximal aspect.
- These consist of triangular-shaped spaces between two teeth, created by the sloping away of the mesial and distal surfaces, and may diverge facially, lingually, occlusally, or apically with loss of tissue. The exception is the last tooth in each arch of each dentition, which lacks a distal contact. The embrasures are continuous with the interproximal spaces between the teeth, and there is an increasing angle of the occlusal embrasures anterioposteriorly. They form spillways between teeth to direct food away from the gingiva. Also, they provide a mechanism for teeth to be more self-cleansing. Finally, the embrasures protect the gingiva from undue frictional trauma but still provide the proper degree of stimulation to the tissue. All these tooth contours (such as contact areas, heights of contour, and embrasures) are important in the function and health of the masticatory system. These specific forms and alignments of the teeth serve to shelter the vulnerable gingivosulcular area from damage and help to stabilize the position of the teeth within each dental arch.
- Each tooth can also be divided by imaginary lines to designate specific crown areas of the tooth. When combining terms such as mesial and labial, the al from the end of the first surface is dropped and an o is added and combined with the second surface, thus creating mesiolabial. If the first letter of the second word results in doubling a vowel, a hyphen is placed between the words, such as mesio-occlusal. An example of line angle designation would be the mesiolabial line angle, which is the junction of the mesial and labial surfaces. Posterior teeth have eight line angles per tooth: mesiobuccal (MB), distobuccal (DB), mesiolingual (ML), distolingual (DL), mesio-occlusal (MO), disto-occlusal (DO), bucco-occlusal (BO), and linguo-occlusal (LO). Anterior teeth have only six line angles per tooth: mesiolabial (ML), distolabial (DL), mesiolingual (ML), distolingual (DL), labioincisal (LI), and linguoincisal (LI). Anteriors have fewer line angles than posteriors because the mesial and distal incisal line angles are rounded; thus, the mesioincisal (MI) and distoincisal (DI) line angles are practically nonexistent.
- Each tooth has four point angles. Examples of point angle designations are mesiolabioincisal for an anterior tooth or mesiobucco-occlusal for a posterior tooth.
- ISO- 1-4 are used for permanent quads, 5-8 are primary quads. 1-8 numbers the teeth with 1 being the central incisor and 8 being the 3rd molar