DOCSLIB.ORG

The Permanent Maxillary and Mandibular Premolar Teeth 39

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Permanent Maxillary and Mandibular Premolar Teeth 39 DOI: 10.5772/intechopen.79464 ProvisionalChapter chapter 2 The Permanent MaxillaryMaxillary andand MandibularMandibular PremolarPremolar Teeth IşılIşıl Çekiç NagaNagaş,ş, Ferhan EEğilmezğilmez andand BaBağdagülğdagül HelvacioHelvacioğluğlu Kivanç Additional information isis available atat thethe endend ofof thethe chapterchapter http://dx.doi.org/10.5772/intechopen.79464 Abstract The permanent premolar teeth are placed between the anterior teeth and molars. Eight premolars are found in the permanent dentition, four per arch and two in each quadrant. The main function of premolars is to assist the canines in regard to tear and pierce the food and supplement the grinding of the molars during mastication. The other functions are to support the corners of the mouth reinforce esthetics during smiling and maintain the vertical dimension. Detailed morphology of the permanent premolar teeth is narrated in a pointwise and systematic manner in this chapter. Keywords: teeth, premolars, dental anatomy 1. Introduction The premolars develop from four lobes with the exception of the mandibular second premolar which develops from five lobes. The facial surfaces of the premolars develop from three facial lobes like anterior teeth. Likewise, the lingual surfaces of most premolars develop from one lingual lobe like anterior teeth. While mandibular first premolars develop from four lobes (mesial, distal, buccal, and lingual) just like the anterior teeth and maxillary premolars, man- dibular second premolars often develop from five lobes (mesial, buccal, distal, mesiolingual, and distolingual lobes). That is why the term “bicuspid” signifies “two cusps,” widely used to describe premolars, may be inappropriate for this group of teeth since the mandibular pre- molars may show a variation in the number of cusps from one to three. In anterior teeth, the lingual lobe forms the cingulum of the incisors and canines. However, in premolar teeth, this lobe forms the lingual cusps. The lingual cusps of mandibular premolars are less prominent © 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and eproduction in any medium, provided the original work is properly cited. distribution, and reproduction in any medium, provided the original work is properly cited. 38 Dental Anatomy than the buccal cusps. There are no deciduous premolars. These teeth erupt at the position previously occupied by the deciduous molars. Timing of teeth eruption can be affected by many factors such as gender, environmental factors and genetic conditions and differs from population to population [1–3]. The agenesis of lower second premolars and maxillary lateral incisors are the most frequent and it could be radio- graphically documented if the median age of emergence of these teeth was passed [1]. On the other hand, caries in primary molar teeth or early extraction of second primary molar could accelerate the eruption time of permanent premolars [1]. The classic sequences of teeth eruption in the maxillae is as follows: first molar, central incisor, lateral incisor, first premolar, canine, second premolar and second molar whereas in the mandible, central incisor, first molar, lateral incisor, canine, first premolar, second premolar and second molar [2]. In addition, generally, in girls, the maxillary canine can be expected before the second premolar, and the mandibular second premolar can be expected before second molar; in boys both orders are reversed [3]. The detailed descriptions of morphologies of from all aspects, chronology of development, form and function, the common characteristics of the permanent premolar teeth were presented in this chapter. In addition, the major differences between these teeth were given in a pointwise and systematic manner [4–11]. 2. The permanent maxillary premolars 2.1. Permanent maxillary first premolars The maxillary first premolar is the fourth permanent tooth from the median line in the maxil- lary arch, located laterally from both the maxillary canines of the mouth but mesial from both maxillary second premolars. It is the first posterior tooth. Chronologic development of the maxillary first premolar is given in Table 1. In the universal system of notation, the right permanent maxillary first premolar is shown as “#5,” and the left one is shown as “#12.” According to the international notation, the right permanent maxillary first premolar is shown as “14,” and the left one is shown as “24.” Besides, in the Palmer notation, the right permanent maxillary first premolar is symbolized as “ ,” the left one is symbolized as “ .” The image of maxillary first premolar from all aspects is seen in Figure 1. A. Buccal, B. Lingual, C. Mesial, D. Distal, E. Occlusal. Development stage Years Initiation of calcification 1 ½–1 ¾ years Enamel completion 5–6 years Eruption 10–11 years Root completion 12–13 years Table 1. Chronologic development of the maxillary first premolar teeth. The Permanent Maxillary and Mandibular Premolar Teeth 39 http://dx.doi.org/10.5772/intechopen.79464 Figure 1. Maxillary first premolar tooth from different aspects. A. Buccal, B. Lingual, C. Mesial, D. Distal, E. Occlusal. The buccolingual dimension is higher than the mesiodistal dimension. The buccal, lingual, and distal surfaces of the crown display convexities in different degrees. 2.1.1. Buccal aspect The pentagonal or trapezoidal shape of the crown is noticeable from the facial aspect. With this form of the crown, the permanent maxillary first premolar appears to be similar to those of the maxillary canine and second premolar. While the canine has a larger size crown with a more prominent cusp tip, the second premolar has a smaller crown with a less prominent cusp tip. Additionally, the crown is smaller in the cervico-occlusal dimension than any anterior tooth, but larger than that of the second premolar or permanent molars. The greatest mesiodistal width of the crown is about 2 mm less at the cervical region. The buccal surface is convex with the exception of the developmental depressions. The well- developed middle buccal lobe forms a continuous ridge from the tip of the buccal cusp to the cervical margin. This ridge is called as “buccal ridge” and demarcates the three developmental lobes. Mesiobuccal and distobuccal developmental depressions exist on both mesial and distal sides of the buccal ridge. These depressions divide the occlusal portion of the buccal surface into vertical thirds, consisting of mesiobuccal, distobuccal, and buccal lobes. Mesiobuccal and distobuccal lobes serve to emphasize strong mesiobuccal and distobuccal line angles on the crown. The imbrication lines are in parallel and semicircular forms and also common in the cervical third of the buccal surface. 40 Dental Anatomy From this aspect, cervical line of the crown is convex. In addition, the curvature depth is less at the cervical margin of the crown than those of anterior teeth. The crest curvature of the cervical line is almost placed at the center of the root. The mesial contour of the crown presents a shallow concavity extending from the cementoenamel junction to the mesial contact area. The highest contour of mesial curvature is at the contact area and located near the junction of the occlusal and middle thirds. The mesial margin of the buccal cusp is lying from the contact area to the tip of the buccal cusp and it creates the mesio-occlusal angle. This margin is less curved and longer than the distal slope of the buccal cusp. The buccal cusp tip is placed slightly toward the distal. Therefore, unequal two portions are seen at the buccal aspect of the crown of occlusal outlines. A concavity or notch may be observed as a result of the developmental depressions passing over the occlusal margin. The distal contour of the crown presents more concave and straighter form below the cementoenamel junction than that of mesial contour. The crest curvature of the distal contact area is located slightly more occlusally. 2.1.2. Lingual aspect The tooth is narrower mesiodistally at the lingual than at the buccal. Therefore, the crown converges toward the lingual cusp. The lingual ridge is barely defined. Both the buccal and lingual cusp tips are visible from this aspect, since the lingual cusp is shorter than the buccal cusp. The lingual cusp of the maxillary first premolar is the shortest of the four maxillary premolar cusps. The lingual portion of the crown is convex and has a spheroidal form. The cervical line at this aspect is regular, with symmetrical curvature toward the root and the crest of curvature is centered on the root. The proximal outlines of the crown at the lingual aspect are convex. These outlines are convex and continuous with the mesial and distal slopes of the lingual cusp. If the tooth presents the severe mesial concavity, the mesial outline may be concave. The lingual cusp tip is situated well anterior (mesial) to the mid-buccolingual diameter of the crown, so the two cusp tips are not placed on the same axis. This cusp tip is not as sharply pointed as the buccal cusp tip. The mesio-occlusal slope of the lingual cusp is shorter than the disto-occlusal slope. The developmental depressions, grooves, or pits are normally not found on the lingual surface. 2.1.3. Mesial aspect From the proximal aspects, all maxillary posterior teeth are present in trapezoidal geometric form. The buccal cusp is longer than the lingual cusp by 1 mm or occasionally more. Well- marked mesial and distal ridges are seen in both cusps. The mesial surface of the crown displays a concavity toward the cementoenamel junction. This concavity extends cervically on the mesial surface and joins a deep developmental depression of the root area.
Load more

Recommended publications
  • Endodontic Therapy of Maxillary Second Molar Showing an Unusual Internal Anatomy
    ISSN: Printed version: 1806-7727 Electronic version: 1984-5685 RSBO. 2012 Apr-Jun;9(2):213-7 Case Report Article Endodontic therapy of maxillary second molar showing an unusual internal anatomy Carlos Eduardo Fontana1 Carolina Davoli Macedo Ibanéz2 Felipe Davini1 Alexandre Sigrist De Martin1 Cláudia Fernandes de Magalhães Silveira1 Daniel Guimarães Pedro Rocha1 Carlos Eduardo da Silveira Bueno1 Corresponding author: Carlos Eduardo Fontana Avenida 02, n.º 1.220 CEP 13500-411 – Rio Claro – SP – Brasil E-mail: [email protected] 1 Department of Endodontics, São Leopoldo Mandic Post-graduation Center – Campinas – SP – Brazil. 2 Private practice – São Paulo – SP – Brazil. Received for publication: October 10, 2011. Accepted for publication: November 11, 2011. Abstract Keywords: internal anatomy; endodontic Introduction: The knowledge of the complex anatomy of maxillary treatment; maxillary molars and location of extra canals are essential for diagnosis second molar; dental and endodontic treatment success. Objective: The purpose of this operating microscope. study was to report a clinical case showing a varying number of palatal roots in a second maxillary molar with the aid of operating microscope (OM). Case report: A four-rooted maxillary permanent second molar with 2 separated palatal canals undergone endodontic therapy. After endodontic access, examination of the chamber floor using an operating microscope revealed two distinct palatal canals orifices. A radiograph was taken after the working lengths of each canal were estimated by means of an electronic apex locator which clearly identified the four roots with independent four canals. The canals were instrumented with ProTaper™ rotatory instruments under irrigation with 5% sodium hypochlorite, obturated with Pulp Canal Sealer® and continue wave technique.
    [Show full text]
  • Material Selection and Shade Matching for a Single Central Incisor
    CLINICAL SCIENCE KAHNG Material Selection and Shade Matching for a Single Central Incisor INTRODUCTION With regard to esthetics, the single central incisor poses the greatest re- by storative challenge for the clinician; not surprisingly, it can also be the most Luke S. Kahng, C.D.T. difficult tooth for the dental technician to match. Selecting the shade of the restoration depends in part on the material used for the understructure, and Mr. Kahng is the founder and owner of there is a wide assortment available from which to choose. The following are Capital Dental Technology Laboratory, among the most common: Inc., in Naperville, Illinois. The labora- tory specializes in all fixed restorations and its LSK 121 division provides per- An experienced technician can mask the underlying dark tooth color using sonalized custom cosmetic work. A porcelains with detailed color-masking techniques. strong proponent of collaborative den- tistry, Mr. Kahng stresses education, communication, and a team approach to patient care. A member of the AACD, UNDERSTRUCTURE MATERIAL his training has included extensive study with Russell DeVreugd, C.D.T., Dr. • Zirconia (e.g., Procera® [Nobel Biocare; Yorba Linda, CA], Lava™ [3M Frank Spear, Dr. Peter Dawson, and ESPE, St. Paul, MN], Cercon® [Dentsply Int., York, PA], Everest™ [KaVo others. America Corp.; Lake Zurich, IL], In-Ceram® [Vident; Brea, CA]) Mr. Kahng is the official clinician for --Flexural strength: approximately 1,200 MPa GC America, Bisco, and Captek. He is --Translucency: very low a frequent lecturer and program facili- tator for dentists and dental technicians, --Opacity: high and has published articles in Practical • Alumina core or glass-infiltrated alumina (e.g., Procera, In-Ceram) Procedures and Aesthetic Dentistry --Flexural strength: 450 to 700 MPa and Dental Dialogue.
    [Show full text]
  • Maxillary Lateral Incisor Agenesis and Its Relationship to Overall Tooth Size Jane Wright, DDS, MS,A Jose A
    RESEARCH AND EDUCATION Maxillary lateral incisor agenesis and its relationship to overall tooth size Jane Wright, DDS, MS,a Jose A. Bosio, BDS, MS,b Jang-Ching Chou, DDS, MS,c and Shuying S. Jiang, MSd Prosthodontists, orthodontists, ABSTRACT and general dentists frequently fi Statement of problem. Agenesis of the maxillary lateral incisor has been linked to differences in encounter dif culties when the size of the remaining teeth. Thus, the mesiodistal space required for definitive esthetic resto- attempting to restore the oc- ration in patients with missing maxillary lateral incisors may be reduced. clusion if unilateral or bilateral Purpose. The purpose of this study was to determine whether a tooth size discrepancy exists in maxillary lateral incisors are orthodontic patients with agenesis of one or both maxillary lateral incisors. congenitally missing. Restora- tion of the missing lateral Material and methods. Forty sets of dental casts from orthodontic patients (19 men and 21 women; mean 15.9 years of age; all of European origin) were collected. All casts had agenesis of one incisor using an implant- or both maxillary lateral incisors. Teeth were measured with a digital caliper at their greatest supported crown, a partial mesiodistal width and then compared with those of a control group matched for ethnicity, age, and fi xed dental prosthesis, or sex. Four-factor ANOVA with repeated measures of 2 factors was used for statistical analysis (a=.05). mesial movement of the Results. Orthodontic patients with agenesis of one or both maxillary lateral incisors exhibited canine are treatment options. smaller than normal tooth size compared with the control group.
    [Show full text]
  • Tooth Size Proportions Useful in Early Diagnosis
    #63 Ortho-Tain, Inc. 1-800-541-6612 Tooth Size Proportions Useful In Early Diagnosis As the permanent incisors begin to erupt starting with the lower central, it becomes helpful to predict the sizes of the other upper and lower adult incisors to determine the required space necessary for straightness. Although there are variations in the mesio-distal widths of the teeth in any individual when proportions are used, the sizes of the unerupted permanent teeth can at least be fairly accurately pre-determined from the mesio-distal measurements obtained from the measurements of already erupted permanent teeth. As the mandibular permanent central breaks tissue, a mesio-distal measurement of the tooth is taken. The size of the lower adult lateral is obtained by adding 0.5 mm.. to the lower central size (see a). (a) Width of lower lateral = m-d width of lower central + 0.5 mm. The sizes of the upper incisors then become important as well. The upper permanent central is 3.25 mm.. wider than the lower central (see b). (b) Size of upper central = m-d width of lower central + 3.25 mm. The size of the upper lateral is 2.0 mm. smaller mesio-distally than the maxillary central (see c), and 1.25 mm. larger than the lower central (see d). (c) Size of upper lateral = m-d width of upper central - 2.0 mm. (d) Size of upper lateral = m-d width of lower central + 1.25 mm. The combined mesio-distal widths of the lower four adult incisors are four times the width of the mandibular central plus 1.0 mm.
    [Show full text]
  • Dental Anatomy Lecture (8) د
    Dental Anatomy Lecture (8) د. حسين احمد Permanent Maxillary Premolars The maxillary premolars are four in number: two in the right and two in the left. They are posterior to the canines and anterior to the molars. The maxillary premolars have shorter crowns and shorter roots than those of the maxillary canines. The maxillary first premolar is larger than the maxillary second premolar. Premolars are named so because they are anterior to molars in permanent dentition. They succeed the deciduous molars (there are no premolars in deciduous dentition). They are also called “bicuspid -having two cusps-“, but this name is not widely used because the mandibular first premolar has one functional cusp. The premolars are intermediate between molars and canines in: Form: The labial aspect of the canine and the buccal aspect of premolar are similar. Function: The canine is used to tear food while the premolars and molars are used to grind it. Position: The premolars are in the center of the dental arch. [Type a quote from the document or the summary of [Type a quote from the document or the summary of an interesting point. You can position the text box an interesting point. You can anywhere in the document. position the text box Use the Text Box Tools tab to anywhere in the document. change the formatting of the Use the Text Box Tools tab to Some characteristic features to all posterior teeth: 1. Greater relative facio-lingual measurement as compared with the mesio-distal measurement. 2. Broader contact areas. 3. Contact areas nearly at the same level.
    [Show full text]
  • TOOTH SUPPORTED CROWN a Tooth Supported Crown Is a Dental Restoration That Covers up Or Caps a Tooth
    TOOTH SUPPORTED CROWN A tooth supported crown is a dental restoration that covers up or caps a tooth. It is cemented into place and cannot be taken out. Frequently Asked Questions 1. What materials are in a Tooth Supported Crown? Crowns are made of three types of materials: • Porcelain - most like a natural tooth in color • Gold Alloy - strongest and most conservative in its preparation • Porcelain fused to an inner core of gold alloy (Porcelain Fused to Metal or “PFM”) - combines strength and aesthetics 2. What are the benefits of having a Tooth Supported Crown? Crowns restore a tooth to its natural size, shape and—if using porce lain—color. They improve the strength, function and appearance of a broken down tooth that may otherwise be lost. They may also be designed to decrease the risk of root decay. 3. What are the risks of having a Tooth Supported Crown? In having a crown, some inherent risks exist both to the tooth and to the crown Porcelain crowns build back smile itself. The risks to the tooth are: • Preparation for a crown weakens tooth structure and permanently alters the tooth underneath the crown • Preparing for and placing a crown can irritate the tooth and cause “post- operative” sensitivity, which may last up to 3 months • The tooth underneath the crown may need a root canal treatment about 6% of the time during the lifetime of the tooth • If the cement seal at the edge of the crown is lost, decay may form at the juncture of the crown and tooth The risks to the crown are: • Porcelain may chip and metal may wear over time • If the tooth needs a root canal treatment after the crown is permanently cemented, the procedure may fracture the crown and the crown may need to be replaced.
    [Show full text]
  • Crown Removal
    INFORMATIONAL INFORMED CONSENT REMOVAL OF CROWNS AND BRIDGES PURPOSE: There are three primary reasons to remove an individual crown or bridge that has been previously cemented to place: 1. Attempt to preserve and reclaim crowns and/or bridges that have fractured while in the mouth; 2. To render some type of necessary treatment to a tooth that is difficult or impossible to perform render treatment without removing the existing crown or bridge; 3. Confirm the presence of dental decay or other pathology that may be difficult to detect or may be obscured while the crown/bridgework is in place. I UNDERSTAND that REMOVAL OF CROWNS AND BRIDGES includes possible inherent risks such as, but not limited to the following; and also understand that no promises or guarantees have been made or implied that the results of such treatment will be successful. 1. Fracture or breakage: Many crowns and bridges are fabricated either entirely in porcelain or with porcelain fused to an underlying metal structure. In the attempt to remove these types of crowns there is a distinct possibility that they may fracture (break) even through the attempt to remove them is done as carefully as possible. 2. Fracture or breakage of tooth from which crown is removed: Because of the leverage of torque pressures necessary in removing a crown from a tooth, there is a possibility of the fracturing or chipping of the tooth. At times these fractures are extensive enough to necessitate extracting the tooth. 3. Trauma to the tooth: Because of the pressure and/or torque necessary in some cases to remove a crown, these pressures or torque may result in the tooth being traumatized and the nerve (pulp) injured which may necessitate a root canal treatment in order to preserve the tooth.
    [Show full text]
  • Maxillary Premolars
    Maxillary Premolars Dr Preeti Sharma Reader Oral & Maxillofacial Pathology SDC Dr. Preeti Sharma, Subharti Dental College, SVSU Premolars are so named because they are anterior to molars in permanent dentition. They succeed the deciduous molars. Also called bicuspid teeth. They develop from the same number of lobes as anteriors i.e., four. The primary difference is the well-formed lingual cusp developed from the lingual lobe. The lingual lobe is represented by cingulum in anterior teeth. Dr. Preeti Sharma, Subharti Dental College, SVSU The buccal cusp of maxillary first premolar is long and sharp assisting the canine as a prehensile or tearing teeth. The second premolars have cusps less sharp and function as grinding teeth like molars. The crown and root of maxillary premolar are shorter than those of maxillary canines. The crowns are little longer and roots equal to those of molars. Dr. Preeti Sharma, Subharti Dental College, SVSU As the cusps develop buccally and lingually, the marginal ridges are a little part of the occlusal surface of the crown. Dr. Preeti Sharma, Subharti Dental College, SVSU Maxillary second premolar Dr. Preeti Sharma, Subharti Dental College, SVSU Maxillary First Premolar Dr Preeti Sharma Reader Oral Pathology SDC Dr. Preeti Sharma, Subharti Dental College, SVSU The maxillary first premolar has two cusps, buccal and lingual. The buccal cusp is about 1mm longer than the lingual cusp. The crown is angular and buccal line angles are more prominent. The crown is shorter than the canine by 1.5 to 2mm on an average. The premolar resembles a canine from buccal aspect.
    [Show full text]
  • Root Canal Morphology and Configuration of 123 Maxillary
    OPEN International Journal of Oral Science (2017) 9,33–37 www.nature.com/ijos ORIGINAL ARTICLE Root canal morphology and configuration of 123 maxillary second molars by means of micro-CT Thomas Gerhard Wolf1, Frank Paqué2, Anja-Christin Woop1, Brita Willershausen1 and Benjamín Briseño-Marroquín1 The aim of this study was to investigate the root canal configuration, accessory canals and number of main foramina of 123 maxillary second molars by means of micro-computed tomography. The teeth were scanned and reproduced with 3D software imaging. The root canal configuration and number of main foramina were evaluated by means of a four-digit system. The morphological complexity of human maxillary second molars is depicted by the number of accessory and connecting canals. The most frequently observed root canal configurations in the mesiobuccal root were 2-2-2/2 (19.5%), 2-2-1/1 (14.6%) and 2-1-1/1 (13.0%). A 1-1-1/1 configuration was observed in 93.5% and in 96.7% in the distobuccal and palatal roots, respectively. The MB1 root canal had one accessory canal (18.7%), and 8.9% of the MB2 root canal had one or two accessory canals. The distobuccal (11.3%) and palatal (14.6%) root canals had at least one accessory canal, and connecting canals were observed in 16.3% of mesiobuccal roots. The MB1, MB2, distobuccal and palatal root canals had one main foramen in 99.2%, 43.1%, 98.4% and 99.2% of samples, respectively. In the mesiobuccal root, one accessory foramen was detected in 14.6%, two were detected in 7.3%, and three were detected in 5.7%.
    [Show full text]
  • Dental Anatomy
    Dental Anatomy: 101 bcbsfepdental.com Learn more about your teeth! What Makes a Tooth? Check out the definitions of the anatomical terms depicted in the diagram to the right. Enamel - Dental enamel is the hard thin translucent layer that serves as protection for the dentin of a tooth. It is made up of calcium salts. It is the hardest substance in the body. Dentin - Dentin is the hard, dense, calcareous (made up of calcium carbonate) material that makes up the majority of the tooth underneath the enamel. It is harder and denser than bone. It is one of four components that make up the tooth. It is the second layer of the tooth. Anatomical Crown - The natural, top part of a tooth, which is covered in enamel and is the part that you can see extending above the gum line. Pulp Chamber – The area within the natural crown of the tooth where the tooth pulp resides. Gingiva – also known as gums – the soft tissues that cover part of the tooth and bone. Gingiva helps protect the teeth The Anatomy of a Tooth from any infection or damage from food and everyday Your teeth are composed of hard (calcified) and soft (non-calcified) interactions with the outer world. dental tissues. Enamel, dentin and Neck - The area of the tooth where the crown joins the root. cementum are hard tissues. Pulp, or the center of the tooth that contains Root Canal – Not to be confused with Root Canal nerves, blood vessels and connective Treatment, the root canal is a space inside your tooth root tissue—is a soft tissue.
    [Show full text]
  • Clinical Significance of Dental Anatomy, Histology, Physiology, and Occlusion
    1 Clinical Significance of Dental Anatomy, Histology, Physiology, and Occlusion LEE W. BOUSHELL, JOHN R. STURDEVANT thorough understanding of the histology, physiology, and Incisors are essential for proper esthetics of the smile, facial soft occlusal interactions of the dentition and supporting tissues tissue contours (e.g., lip support), and speech (phonetics). is essential for the restorative dentist. Knowledge of the structuresA of teeth (enamel, dentin, cementum, and pulp) and Canines their relationships to each other and to the supporting structures Canines possess the longest roots of all teeth and are located at is necessary, especially when treating dental caries. The protective the corners of the dental arches. They function in the seizing, function of the tooth form is revealed by its impact on masticatory piercing, tearing, and cutting of food. From a proximal view, the muscle activity, the supporting tissues (osseous and mucosal), and crown also has a triangular shape, with a thick incisal ridge. The the pulp. Proper tooth form contributes to healthy supporting anatomic form of the crown and the length of the root make tissues. The contour and contact relationships of teeth with adjacent canine teeth strong, stable abutments for fixed or removable and opposing teeth are major determinants of muscle function in prostheses. Canines not only serve as important guides in occlusion, mastication, esthetics, speech, and protection. The relationships because of their anchorage and position in the dental arches, but of form to function are especially noteworthy when considering also play a crucial role (along with the incisors) in the esthetics of the shape of the dental arch, proximal contacts, occlusal contacts, the smile and lip support.
    [Show full text]
  • Oral Structure, Dental Anatomy, Eruption, Periodontium and Oral
    Oral Structures and Types of teeth By: Ms. Zain Malkawi, MSDH Introduction • Oral structures are essential in reflecting local and systemic health • Oral anatomy: a fundamental of dental sciences on which the oral health care provider is based. • Oral anatomy used to assess the relationship of teeth, both within and between the arches The color and morphology of the structures may vary with genetic patterns and age. One Quadrant at the Dental Arches Parts of a Tooth • Crown • Root Parts of a Tooth • Crown: part of the tooth covered by enamel, portion of the tooth visible in the oral cavity. • Root: part of the tooth which covered by cementum. • Posterior teeth • Anterior teeth Root • Apex: rounded end of the root • Periapex (periapical): area around the apex of a tooth • Foramen: opening at the apex through which blood vessels and nerves enters • Furcation: area of a two or three rooted tooth where the root divides Tooth Layers • Enamel: the hardest calcified tissue covering the dentine in the crown of the tooth (96%) mineralized. • Dentine: hard calcified tissue surrounding the pulp and underlying the enamel and cementum. Makes up the bulk of the tooth, (70%) mineralized. Tooth Layers • Pulp: the innermost noncalsified tissues containing blood vessels, lymphatics and nerves • Cementum: bone like calcified tissue covering the dentin in the root of the tooth, 50% mineralized. Tooth Layers Tooth Surfaces • Facial: Labial , Buccal • Lingual: called palatal for upper arch. • Proximal: mesial , distal • Contact area: area where that touches the adjacent tooth in the same arch. Tooth Surfaces • Incisal: surface of an incisor which toward the opposite arch, the biting surface, the newly erupted “permanent incisors have mamelons”: projections of enamel on this surface.
    [Show full text]