Permanent Maxillary Lateral Incisor PDF

## Permanent Maxillary Lateral Incisor ### Mesial Aspect - The mesial aspect is similar to that of a small maxillary central incisor, except: - The crown is shorter, the root is relatively longer. - The incisal portion is thicker and more rounded. - The root appears as a tapered cone f...

## Permanent Maxillary Lateral Incisor ### Mesial Aspect - The mesial aspect is similar to that of a small maxillary central incisor, except: - The crown is shorter, the root is relatively longer. - The incisal portion is thicker and more rounded. - The root appears as a tapered cone from this aspect, with a blunt apex. ### Distal Aspect - Is similar to that of the mesial, except: - The crown is thicker. - The cervical line is shallower (less in depth) than mesially. ### Incisal Aspect - Usually resembles the central incisor but exhibits more convexity labially and lingually and is smaller in size. - Or in some variations it may resemble that of a small canine, if the labiolingual dimension is greater than usual in comparison with the mesiodistal dimension. ## Anomalies of The Permanent Maxillary Lateral Incisor 1. **Peg-shaped lateral incisor.** 2. **Congenitally missing lateral incisor** 3. **Lingual pit and groove** - The presence of a palatogingival groove in maxillary incisors may be a predisposing factor in localized periodontal disease also referred to as palatoradicular groove. 4. **Lingual tubercle** ## Incisal Aspect ### Geometric outline of the crown: - Triangular; the base is located labially and the apex linguall - The mesiodistal dimension of the crown is larger than the labiolingual. - The labial surface is broad and flat. - The cervical portion of the crown is convex (cervical ridge). - The lingual outline tapers lingually (lingual convergence). - The crown superimposes the root. - The cingulum makes up the cervical portion of the lingual surface. - The fossa is bordered by the cingulum, 2 well developed mesial and distal marginal ridges and the incisal ridge. ## Anomalies - The maxillary central incisor usually develops normally. - One anomaly that sometimes occurs is a short root. Another variation is an unusually long crown. ## Anterior Teeth - Anterior teeth include the maxillary and mandibular incisors and canines. - There are 4 maxillary incisors and 4 mandibular incisors. - Two central incisors are centered in the maxilla, one on either side the median line. - The central incisors are the only neighboring teeth with the mesial surfaces in contact - Two lateral incisors are distal to the central incisors. - All incisors are formed four lobes 3 labial and I lingual). ## Permanent Maxillary Central Incisor - The maxillary central incisors are larger than the lateral incisors and are the widest mesiodistally of all anterior teeth. ### Chronology: | | Time Frame | |---|---| | Evidence of Calcification | 3 to 4 Months | | Enamel Completed | 4 to 5 Years | | Eruption | 7 to 8 Years | | Root Completed | 10 Years | - A space between the central incisors or other teeth is called "Diastema". ## Permanent Maxillary Lateral Incisor - The Maxillary lateral incisor supplements the central incisor in function. - It resembles the central incisor in form but smaller in all dimensions except root length. - The crown has more curvature with a rounded incisal ridge & rounded incisal angles mesially & distally. ### Labial Aspect - Geometric shape - crown: Trapezoidal; with the shorter uneven side located cervically. - The Crown: - Mesial outline: slightly convex. - Distal outline: always more convex. - Incisal outline: curved & rounded. - Contact areas - Mesial contact area is located at the junction of middle and incisal thirds. - Distal contact area is more cervical located at the center of middle 1/3. - Mesioincisal angle: rounded - Distoincisal angle: more rounded - The cervical line: Convex root wise. - The Root: - The root length is greater in proportion to the crown than that of the maxillary central. - The root is often about 1.5 times the length of the crown. - The root tapers evenly approximately two thirds of its length then it curves distally. - It ends in a pointed apex ### Lingual Aspect - The outline is a mirror image of that of the labial. - The tooth tapers towards the lingual. - The lingual surface shows elevations and a concavity. - Elevations: - Prominent cingulum (present at cervical 1/3). - Marked mesial and distal Marginal ridges. - Incisal ridge. - Depressions: - The lingual fossa is more concave and circumscribed. - It is not uncommon to find a deep developmental groove at the side of the cingulum, usually on the distal side, which may extend up on the root for part or all of its length. ### Chronology: | Stage | Time Frame | |---|---| | 1" Evidence of Calcification | 1 Year- | | Enamel Completed | 4 to 5 Years | | Eruption | 8 to 9 Years | | Root Completed | 11 Years | ## Central Fossa - Is located on the occlusal surfaces of molars. - It may be circular or irregular. - It is formed at the point of terminals of the triangular ridges of cusps. ## Pit - Small pinpoint depressions located at the junction developmental grooves or at terminals of those grooves. - For instance, central pit is a term used to describe a landmark in the Central fossa of molars where developmental grooves join. ## Notation Systems - Systems used to identify the type of each tooth and its location in each quadrant of the dental arches. - They are used to identify and refer to a specific tooth and as a quick short cut in clinical records. ### Palmer Notation System - Used in Egypt. - Teeth are arranged in 2 crossed lines representing the 4 quadrants. - Permanent Teeth - Are given numbers starting from 1 (the central incisor) and ending by 8 (the third molar). - Primary (Deciduous) Teeth - Are given Letters starting from A (the central incisor) and ending by E (the second molar). ### Universal Notation System - A specific number is given for each permanent tooth and a letter for each deciduous tooth. - The first number (1) is given to the right maxillary permanent third molar and the first letter (A) to the deciduous maxillary right second molar. - The permanent teeth are numbered 1 through 32 starting by 1 at the right third molar. - The deciduous teeth are designated with the capital letters A through T starting by A for the deciduous maxillary second molar. - The sequence of numbers or letters in this system goes in a clockwise direction through the 4 quadrants. - The number or letter used in this system is always preceded by the sign # to indicate that the system used is Universal system. ### Permanent Teeth | Quadrant | Teeth | |---|---| | R | 1 2 3 4 5 6 7 8 | | | 10 11 12 13 14 15 16 | | | 32 31 30 29 28 27 26 25 | | | 24 23 22 21 20 19 18 17 | | L | | ### Deciduous Teeth | Quadrant | Teeth | |---|---| | R | A B C D E T S R Q P | | L | F G H I J O N M L K| ### Exercise - 2.3 - 8.2 - #K - #32 - #A ## Development And Eruption Of Teeth - The development of the crown and the root takes place within the bony crypt of the jaw. - After the crown of the tooth is completely formed, development of the root portion begins. - The emergence of the tooth through the gingiva and its appearance in the oral cavity is termed (eruption). - When the tooth erupts in the oral cavity, the full crown and about half of the root are formed. - Eruption is almost complete when the crown has made contact with its antagonist tooth in the opposing jaw. - Complete formation of the root takes place between 1 and 1.5 years in deciduous teeth and between 2.5 and 3 years in permanent teeth. - The tooth is completely formed when the apex of the root is formed. ## Labial Aspect - Geometric outline of the crown: Trapezoidal with the shortest uneven side located cervically. - This outline is characteristic for all teeth facially and lingually. - The Crown: - Mesial outline is slightly convex. - Distal outline is more convex, - Incisal outline is regular and straight. - In newly erupted teeth, mamelons are seen on the incisal ridge, the middle one is the smallest. - The labial surface is smooth and convex. - Shows developmental lines which divide the surface into 3 parts. (lobes) - Contact areas - The mesial contact area is near the mesio-incisal angle. - The distal contact area is at the junction between incisal and middle thirds. - The mesio-incisal angle is sharp - The disto-incisal angle is rounded. - The cervical line is (semicircular) convex root wise. - The root: - It has a single root. - It is cone shape with blunt apex. - The root is 2-3 mm longer than the crown. ## Chronology Of Deciduous Teeth - Calcification of deciduous teeth begins by the 6th month of intrauterine life. - The deciduous incisors and first molars are the first teeth to erupt, followed by the canines and second molars. - In contrary to permanent teeth, maxillary teeth erupt before their mandibular counterparts except the mandibular central incisor and mandibular second molar. - The most common sequence of deciduous teeth eruption: - A B D C E - A B D C E ## Chronology Of Permanent Teeth - The first permanent teeth to erupt are the first permanent molars. They emerge immediately distal to the deciduous second molars by 6 years of age. - The mandibular permanent teeth precede the maxillary teeth in eruption except the premolars. ### Sequence of permanent teeth eruption in Maxillary arch: - 6-1-2-4-5-3-7-8 or - 6-1-2-4-3-5-7-8 ### Sequence of permanent teeth eruption in Mandibular arch: - (6-1)-2-3-4-5-7-8 or - (6-1)-2-4-3-5-7-8 ## FDI Notation System - A two-digit system proposed by Federation Dentaire Internationale (FDI). - It is the system of choice worldwide and adopted by the World Health Organization (WHO) and accepted by many dental organizations. - In this system each tooth is given a number of 2 digits. - The first number is the quadrant number given in a clockwise direction starting from the right maxillary quadrant. - The second number indicates the number of the tooth within any quadrant. ## Lingual Aspect - The outline is a mirror image of that of the labial. - It has the same geometric outline of the crown. - The crown and root tapers lingually making the lingual surface narrower than the labial. - The lingual surface shows elevations and a concavity. - Elevations (convexities): - The cingulum (present at cervical 1/3). - Mesial and distal Marginal ridges. (MMR and DMR) - An exaggeration of the marginal ridges, known as a shovel-shaped incisor, is a genetically determined variation seen in Mongoloid races. - Incisal ridge. - Incisal ridge is present in newly erupted teeth, the incisal edge is created after incisal wear due to forces of mastication. - Depression (Concavity): - Lingual fossa - Below the cingulum and between the ridges is a shallow concavity known as lingual fossa. - Triangular or M shaped. - A cross section of the root at the cervix is triangular with rounded angles, its base at the labia with the mesial and distal sides pointing lingually. ## The Crown - Triangular or wedge; the base located cervically and the apex incisally. - The labial outline is convex at cervical 1/3. - The lingual outline is convex at cervical 1/3 (cingulum). - Then concave at the lingual fossa. - Then slightly convex for the incisal ridge. - The labial and lingual crest of curvature are at center of cervical third - The incisal ridge is on a line with the center of the root. - The mesial cervical line is concave root wise. Its curvature is greater than any other teeth in the mouth. - The root: - It is cone shape with blunt apex. ## Distal Aspect - Similar to the mesial aspect with several differences: - The outline form is the reverse of the mesial. - The crown appears thicker at the Incisal 1/3. - The cervical line curvature is less by 1 mm than