Oral Anatomy and Occlusion: Maxillary and Mandibular Central Incisors PDF

The age of the erruptions *please study this.  ORAL ANATOMY AND OCCLUSION: MAXILLARY AND MANDIBULAR CENTRAL INCISORS PERMANENT MAXILLARY CENTRAL INCISORS ▪ They also play an important role in the esthetics...

The age of the erruptions *please study this.  ORAL ANATOMY AND OCCLUSION: MAXILLARY AND MANDIBULAR CENTRAL INCISORS PERMANENT MAXILLARY CENTRAL INCISORS ▪ They also play an important role in the esthetics and phonetics functions of the human teeth. DEVELOPMENT TABLE: PERMANENT MAXILLARY CENTRAL INCISOR Initiation of 3-4 months Calcification Completion of 4-5 years Enamel Eruption 7-8 years GENERAL CHARACTERISTICS: PERMANENT MAXILLARY Completion of Root 10 years CENTRAL INCISOR COMPARISON TO THE LATERAL INCISORS:PERMANENT MAXILLARY CENTRAL INCISOR ▪ These teeth have incisal ridges or edges rather than cusps such as are found on the canines and posterior teeth. ▪ The incisors are shearing or cutting teeth. a. Arch Position o The maxillary central incisors are the two teeth which are adjacent to the midline in the upper arch. o They share a mesial area with each other and have a distal contact with the lateral incisors. ▪ The maxillary central incisors are centered in the b. Universal Number maxilla, one on either side of the median line, o Maxillary Right Central Incisor - #8 with the mesial surface of each in contact with o Maxillary Left Central Incisor - #9 the mesial surface of the other. c. FDI o Maxillary Right Central Incisor – #11 o Maxillary Left Central Incisor - #21 d. Palmer’s o Maxillary Right Central Incisor – o Maxillary Left Central Incisor - GENERAL FORM AND FUNCTION: PERMANENT MAXILLARY CENTRAL INCISOR ▪ As viewed from the labial or lingual aspects, the ▪ The maxillary central incisors are larger than the crown is trapezoidal in shape, and the widest lateral incisors. mesiodistally of any anterior tooth. ▪ These teeth supplement each other in function, ▪ As viewed from either proximal aspect, the and they are similar anatomically. crown is triangular. ▪ The general crown size exceeds that of any other incisor in either arch. ▪ The central incisors’ functions in mastication are biting, cutting, incising, and shearing. BE NICERIO, RAFFY 1  ORAL ANATOMY AND OCCLUSION: MAXILLARY AND MANDIBULAR CENTRAL INCISORS INCISAL ASPECT: PERMANENT MAXILLARY CENTRAL LABIAL VIEW: PERMANENT MAXILLARY CENTRAL INCISOR INCISORS ▪ The labial surface is less convex than that of the maxillary lateral incisor or canine, which gives the central incisor a square or rectangular appearance. ▪ The Incisal Ridge o Is that portions of the crown which makes up the complete incisal portion. o When an incisor is newly erupts, the ▪ From this aspect, the crown nearly always incisal portion is rounded and looks symmetrical and regularly formed, emerges with the mesioincisal and having a nearly straight incisal edge, a Distoincisal angles and the labial and cervical line with even curvature toward the lingual surfaces. root, a mesial side with straight outline, the o This ridge portion of the crown is distal side being more curved. called the incisal ridge. ▪ The mesial incisal angle is relatively sharp, ▪ The Incisal Edge the distal incisal angle rounded. o Is formed by the junction of the linguoincisal surface, sometimes called the Incisal Surface, and the Labial Surface. ▪ The crest of curvature mesially and distally on the crown represent the areas at which the central incisor contacts its neighbors. ▪ The crest of curvature (contour) is defined as the widest area of the crown of the tooth. ▪ The Maxillary central incisor is the widest mesiodistally of any of the anterior teeth. ☆ NICERIO, RAFFY 2  ORAL ANATOMY AND OCCLUSION: MAXILLARY AND MANDIBULAR CENTRAL INCISORS LABIAL VIEW: PERMANENT MAXILLARY CENTRAL o They are normally worn away rather INCISORS soon after eruption, if the tooth contacts its antagonist in the opposite arch when in function. ▪ The mesial outline of the crown is only slightly convex, with the crest of curvature (representing the contact area) approaching the mesioincisal ▪ The cervical outline of the crown follows a angle. semicircular direction with the curvature root ▪ The distal outline of the crown is more convex wise. than the mesial outline, with the crest of ▪ The root of the central incisor from the labial curvature higher toward the cervical line. aspect is cone-shaped, in most instances with a ▪ The Distoincisal angle is not as sharp as the relatively blunt apex, and the outline mesially and mesioincisal angle. distally is regular. ▪ The root is usually 2-3 mm longer than the crown, although it varies considerably. ▪ The incisal outline is usually regular and straight in a mesiodistal direction after the tooth has been in function long enough to obliterate the mamelons. ▪ The line drawn though the center of the root and crown of the maxillary central incisor tends to parallel the mesial outline of the crown and root. ▪ Mamelons o Small, rounded projections of enamel which are found in varying sizes and numbers on the incisal ridges if recently erupted incisors. TITI NICERIO, RAFFY 3  ORAL ANATOMY AND OCCLUSION: MAXILLARY AND MANDIBULAR CENTRAL INCISORS LINGUAL ASPECT: PERMANENT MAXILLARY CENTRAL MESIAL ASPECT: PERMANENT MAXILLARY CENTRAL INCISOR INCISOR ▪ The lingual outline of the maxillary central incisor is the reverse of that found on the labial aspect. ▪ The mesial aspect of this tooth has the fundamental form of an incisor. ▪ The crown is wedge-shaped, or triangular, with the base of the triangle at the cervix and the apex at the incisal ridge. ▪ A line drawn through the crown and the root ▪ From the labial aspect, the surface of the crown from the mesial aspect through the center of the is smooth in generally. tooth will bisect the apex of the root and also the ▪ The lingual aspect has convexities and a incisal ridge of the crown. concavity. ▪ The incisal ridge of the crown is therefore on a ▪ The outline of the cervical line is similar, but line with the center of the root. immediately below the cervical line a smooth convexity is to be found; this is called “Cingulum”. ▪ The Cervical Line outlining the CEJ mesially on the maxillary central incisor curves incisally to a noticeable degree. T oo NICERIO, RAFFY 4  ORAL ANATOMY AND OCCLUSION: MAXILLARY AND MANDIBULAR CENTRAL INCISORS ▪ This cervical curvature is greater on the mesial DISTAL ASPECT: PERMANENT MAXILLARY CENTRAL surface of this tooth than on any surface of any INCISOR other tooth in the mouth. ▪ Little difference is evident between the distal and ▪ Labially and lingually, immediately coronal to the mesial outlines of this tooth. cervical line are the crest of curvature of these ▪ When looking at the central incisor from the surfaces. distal aspect, it may be noted that the crown ▪ These crests of contour give the crown its gives the impression of being somewhat thicker greatest labiolingual measurement. toward the incisal third. ▪ Because of the slope of the labial surface distolingually, more of that surface is seen from the distal aspect; this creates the illusion of greater thickness. ▪ The curvature of the cervical line outlining the CEJ is less in extent on the distal than on the mesial surfaces. *Most teeth show these characteristics* INCISAL ASPECT: PERMANENT MAXILLARY CENTRAL ▪ The labial outline of the crown from the crest of INCISOR curvature to the incisal ridge is very slightly convex. ▪ The lingual outline is convex at the point where it joins the crest of curvature at the cingulum; it them becomes concave at the mesial marginal ridge and slightly convex again at the linguoincisal ridge and the incisal edge. ▪ A view of the crown from this aspect superimposes it over the root entirely so that the latter is not visible. - NICERIO, RAFFY 5  ORAL ANATOMY AND OCCLUSION: MAXILLARY AND MANDIBULAR CENTRAL INCISORS ▪ A mid root cross section usually reveals a somewhat ovoid outline, which is wider labiolingually than mesiodistally. ▪ The labial surface of the crown is relatively broad and flat in comparison with the lingual surface, especially toward the incisal third. ▪ The labial and lingual outlines are convex to ▪ The incisal ridge may be seen clearly, and a different extent. differentiation between the incisal edge and the ▪ The labial outline is only slightly convex, while remainder of the incisal ridge, with its slope the lingual outline is quite convex, due to the toward the lingual, is easily distinguished. prominence of the cingulum. ▪ The outline of the lingual portion tapers lingually toward the cingulum. ▪ The cingulum of the crown makes up the cervical portion of the lingual surface. ▪ The mesiolabial and distolabial line angles are prominent from the incisal aspect. ▪ The crown conforms to a triangular outline. ROOT ASPECT: PERMANENT MAXILLARY CENTRAL ▪ The root length is approximately one and a half INCISOR times the crown length. VARIATIONS AND ANOMALIES: PERMANENT MAXILLARY CENTRAL INCISORS ▪ The root is single, conical, relatively straight, and tapers to a rounded apex. ▪ A horizontal cross section of the root near the ▪ Of all the crown surfaces, the lingual exhibits the cervical line shows a rounded triangular outline. greatest variation. ▪ Normally, the root is wider at the labial, which is ▪ As previously mentioned, a pit may occasionally the base of the triangle, and a narrower at the be present, and the depth of the fossa has a lingual which is the apex. considerable range. ▪ When viewed from the labial or lingual aspects, a wide variation occurs in the amount of - NICERIO, RAFFY 6  ORAL ANATOMY AND OCCLUSION: MAXILLARY AND MANDIBULAR CENTRAL INCISORS convergence of the mesial and distal surfaces towards the cervical. ▪ Root length may vary considerably, but ▪ Talon Cusps deflections of the root are relatively rare. o A large accessory cusp on the lingual ▪ When the root is exceptionally short, in surface of maxillary incisors conjunction with an abnormal contour of the characterizes this anomaly. crown, this anomalous condition is referred o Involved teeth often bear a resemblance to as “Dwarfed Tooth”, and the lack of root to a Phillips Screwdriver. support may endanger the tooth’s longevity in the mouth. ▪ Mesiodens o The alveolar bone between the roots of the two central incisors is occasionally ▪ Hutchinson’s Incisors the site of supernumerary teeth, or extra o Congenital syphilis sometimes manifests teeth. itself in the central incisor by producing o Extra tooth that’s located behind or a screwdriver shaped crown when it is between your two front teeth. viewed from the labial aspect. ▪ Congenital Syphilis o Is a chronic infectious disease cased by Spirochete (treponema pallidum) acquired by the fetus in the uterus before birth. o Syphilis is a sexually transmitted infection (STI). - NICERIO, RAFFY 7  ORAL ANATOMY AND OCCLUSION: MAXILLARY AND MANDIBULAR CENTRAL INCISORS PERMANENT MANDIBULAR CENTRAL INCISORS line, with the mesial surface of each one in contact with the mesial surface of the other. GENERAL CHARACTERISTICS: PERMANENT ▪ The right and left mandibular lateral incisors are MANDIBULAR CENTRAL INCISORS distal to the central incisors. ▪ The mandibular incisors have smaller mesiodistal a. Arch Position dimensions than any of the other teeth. o The mandibular central incisors occupy ▪ The central incisor is somewhat smaller than the the position adjacent to the midline in lateral incisor, which is the reverse of the each mandibular quadrant. situation in the maxilla. o They share a mesial contact area with each other, while the distal contact is with the permanent lateral incisors. b. Universal Number o Mandibular Right Central Incisor - #25 o Mandibular Left Central Incisor - #24 c. FDI o Mandibular Right Central Incisor - #41 ▪ These teeth are similar in form and have smooth o Mandibular Left Central Incisor - #31 crown surfaces that show few traces of d. Palmer’s developmental lines. ▪ Mamelons on the incisal ridges are worn off o Mandibular Right Central Incisor - soon after eruption, if the occlusion is normal, o Mandibular Left Central Incisor - which leaves the incisal ridges smooth and GENERAL FORM AND FUNCTION: PERMANENT straight. MANDIBULAR CENTRAL INCISOR ▪ The contact areas are near the incisal ridges mesially and distally, and lines drawn through the contact areas are near the same level on both central and lateral incisors. DEVELOPMENT TABLE: PERMANENT MANDIBULAR ▪ The mandibular central incisor normally ahs the CENTRAL INCISOR narrowest mesiodistal dimension and the smallest crown size of any permanent tooth. Initiation of 3-4 months ▪ The crown is also quite symmetrical, with the Calcification mesial and distal halves nearly identical. Completion of 4-5 years ▪ These teeth function in biting, cutting, incising, Enamel and shearing just as do their maxillary Eruption 6-7 years counterparts. Completion of 9 years ▪ The mandibular central incisors are centered in Root the mandible, one on either side of the median So NICERIO, RAFFY 8  ORAL ANATOMY AND OCCLUSION: MAXILLARY AND MANDIBULAR CENTRAL INCISORS LABIAL ASPECT: PERMANENT MANDIBULAR CENTRAL o In fact, in some specimens the labial INCISOR surface may be quite flat incisal to the height of contour. ▪ Mesial Outline o The mesioincisal angle is quite sharp, normally more so than any of the incisal angles of maxillary incisors. o The surface outline is roughly o The height of contour is associated with trapezoidal, which in some cases the contact areas in the incisal third, approaches a rectangular shape. very close to the incisal margin. o Developmental depressions and ▪ Distal Outline imbrication lines are not normally o Distally, the outline is straight and present. almost exactly like the mesial outline. o The height of contour is also in the incisal third. ▪ Incisal Outline o When present, mamelon are mostly in o Occasionally, there are very faint threes. depressions which only occur near the o After incisal wear has obliterated the incisal margin of the labial surface. mamelons, the incisal outline is straight, ▪ The height of contour is in the cervical third. and it right angles to the long axis of the tooth. ▪ Cervical Outline o The cervical line is symmetrically curved towards the root. ▪ Other Considerations o The labial surface is generally convex both mesiodistally and Incisogingivally, but not to the extent of the maxillary incisors. - NICERIO, RAFFY 9  ORAL ANATOMY AND OCCLUSION: MAXILLARY AND MANDIBULAR CENTRAL INCISORS LINGUAL ASPECT: PERMANENT MANDIBULAR o A cingulum is normally present, although CENTRAL INCISOR it is not so prominent as in the maxillary incisors. ▪ The height of contour is located in the cervical third of the surface, associated with the greatest ▪ Mesial, Distal, and Incisal Outline convexity of the cingulum. o All three of these margins closely MESIAL ASPECT: PERMANENT MANDIBULAR CENTRAL resemble those of the labial aspect. INCISOR ▪ Cervical Outline o The CEJ curves evenly toward the root but is located farther from the incisal edge than it is on the labial surface. ▪ Other Considerations o The lingual surface is relatively smooth, and its structures are generally less prominent than those of the maxillary incisors. o There is usually a slightly concavity, or lingual fossa bordered by indistinct marginal ridges on the mesial and distal. o There are normally no grooves, fissures, or pits on the lingual surface. ▪ Labial Outline o The labial margins slope in a slightly convex line from the incisal ridge to the crest of curvature and is them convex in the remainder of the gingival third. ▪ Lingual Outline o The lingual outline is concave in the incisal two-thirds and convex in the cingulum area, or gingival third. ▪ Incisal Outline o The incisal edge is normally straight, but can be slightly rounded, and is located lingual to the center of the tooth. F- NICERIO, RAFFY 10  ORAL ANATOMY AND OCCLUSION: MAXILLARY AND MANDIBULAR CENTRAL INCISORS o The profile of the incisal edge has an DISTAL ASPECT: PERMANENT MANDIBULAR CENTRAL inclination toward the labial, which is INCISOR opposite to the lingual slope of the maxillary incisors. o This is due to the wear pattern between the upper and lower incisors. ▪ The distal surface is similar in all respects to the mesial, except that the cervical margin curves ▪ Cervical Outline slightly less towards the incisal. o There is a marked, even curvature ▪ Even the contact area has a similar location, a incisally of the cervical margin. fact which is unique among incisors. ▪ Other Considerations Incisal Aspect: Permanent Mandibular Central Incisor o The mesial surface is roughly triangular, or wedge shaped, like all other anterior teeth. o Unlike the maxillary incisors, the crown appears to be slightly offset toward the lingual. o The contact area is located about halfway from the labial to lingual and in the incisal third, very close to the incisal edge. o It has an ovoid shape, which is long Incisogingivally and narrow labiolingually. o The height of contour, at the contact ▪ The most notable features from the incisal area is in the incisal third. aspect are the symmetry of the mesial and distal portions, and the straight incisal edge. ▪ Unlike the maxillary central, this tooth is roughly four sided, or diamond-shaped, from this aspect and the tooth is normally wider labiolingually than mesiodistally. -00 NICERIO, RAFFY 11  ORAL ANATOMY AND OCCLUSION: MAXILLARY AND MANDIBULAR CENTRAL INCISORS ▪ Because the crown is offset toward the lingual, ▪ When concave, the surface is said to have a root more of the labial surface than the lingual concavity which is also known as s “Longitudinal surface is visible from this aspect. Groove”. ▪ Even though the central incisor is describing as ▪ Root concavities are found on the roots of other symmetrical from the incisal aspect, careful teeth, and usually extend the majority of the root scrutiny will reveal that the cingulum is very length, but vary in both length and depth. slightly offset toward the distal, an important VARIATIONS AND ANOMALIES: PERMANENT feature when attempting to distinguish right from MANDIBULAR CENTRAL INCISORS left mandibular central incisors. ROOT: PERMANENT MANDIBULAR CENTRAL INCISOR ▪ There is a great variability in the lingual inclination of the labial surface of mandibular ▪ The root is normally single and straight. central incisor specimens. ▪ From the labial or lingual aspects, the root is ▪ Anomalies are very rare. generally symmetrical, and tapers gradually to a ▪ Occasionally a bifurcated root is found. relatively sharp apex. ▪ From the mesial or distal aspects, the root is much wider, and it is slightly convex cervicoapically on both labial and lingual margins. ▪ The central position of the mesial and distal surfaces is usually flattened, or concave. D- NICERIO, RAFFY 12  PERMANENT MAXILLARY AND MANDIBULAR LATERAL INCISORS PERMANENT MAXILLARY LATERAL INCISORS ▪ The upper lateral incisors display greater variation in form than any other permanent ARCH POSITION: MAXILLARY LATERAL INCISORS tooth, except the third molars. DEVELOPMENT TABLE: MAXILLARY LATERAL INCISOR Initiation of Calcification 1 year Completion of Enamel 4-5 years Eruption 8-9 years Completion of Root 11 years ▪ The maxillary lateral incisor is the tooth in each ▪ Initial calcification beings in the deciduous maxillary quadrant of the permanent dentition. central incisors as early as 12 weeks or as late ▪ Second from the midline as 16 weeks. ▪ Contact is shared with the permanent central ▪ The ages at which deciduous teeth begin to incisor on the mesial aspect. calcify in utero were given as central incisors at ▪ While distal contact is with the deciduous canine. 18 weeks, lateral incisors at 19 weeks, canines ▪ Exfoliation at age of 12 and first molars at 20 weeks, maxillary second UNIVERSAL NUMBER molars at 22 weeks, and mandibular second molars at 25 weeks. ▪ Maxillary Right Lateral Incisor - #7 LABIAL ASPECT: MAXILLARY LATERAL INCISOR ▪ Maxillary Left Lateral Incisor - #10 FDI ▪ Maxillary Right Incisor - #12 ▪ Maxillary Left Lateral Incisor -#22 PALMERS ▪ Maxillary Right Incisor - ▪ Maxillary Left Incisor - GENERAL FORM AND FUNCTION ▪ Mesial Outline – this margin resembles that of ▪ The lateral incisor supplements the central the central incisor, but usually is more convex incisor in function. and has more rounded mesioincisal angle. The ▪ It resembles the central incisor in all aspect, but crest of curvature at the contact area is located on a smaller scale. farther gingivally in the incisal third, quite near its ▪ Lateral is smaller in all measurements but root junction with the middle third. length with the central incisors is roughly the same. ▪ Lateral Incisor is Longer Incisocervically and Narrower Mesiodistally ▪ It also is generally a more round tooth than the central incisor. So NICERIO, RAFFY 1  PERMANENT MAXILLARY AND MANDIBULAR LATERAL INCISORS Teeth have a labial and lingual extent of the crest of curvature of 0.5mm. ▪ Cervical Outline – the cervical line curves in a regular arc apically, with only slightly less depth than in the central incisor. ▪ Other Considerations o the labial surface itself is more convex both mesiodistally and incisogingivally than the maxillary central. ▪ Distal Outline – the distal margin is always more o Labial developmental depressions and rounded than the distal outline of the central imbrication lines are often present. incisors. With more cervically placed crest of Similar to those of the central incisor. curvature, usually at the junction of the incisal o The labial height of contour is located in and middle thirds the cervical third. Mamelons ▪ Are small, rounded projections of enamel which LINGUAL ASPECT: MAXILLARY PERMANENT LATERAL are found in the incisal ridges of recently erupted INCISOR incisors. ▪ Mesial Margin o The mesial outline is similar to that of ▪ Incisal Outline – the incisal outline resembles the central incisor. the central incisor but is not so straight. Partially ▪ Distal Margin because of the greater rounding of the two o This margin is also similar to its central incisal angles. It exhibits the greatest rounding of incisor counter- part, and the distoincisal any incisor. The number and prominence of the angle is much more rounded than is the mamelons is variable, but two are the most mesioincisal angle. common finding. LABIAL ASPECT: MAXILLARY PERMANENT LATERAL INCISOR ▪ Incisal Outline o The incisal margin is similar to the labial aspect. ▪ Cervical Outline ▪ This is a horizontal measurement of how “Bulbous” the tooth is. The Maxillary Anterior not NICERIO, RAFFY 2  PERMANENT MAXILLARY AND MANDIBULAR LATERAL INCISORS o The CEJ curves toward the apical, but is MESIAL ASPECT: PERMANENT MAXILLARY LATERAL offset to the distal. INCISOR ▪ Other considerations o The mesial and distal marginal ridges, as well as the cingulum, are relatively more prominent, and the lingual fossa is deeper when compared to the same structures of the central incisors. LINGUAL ASPECT: PERMANENT MAXILLARY LATERAL ▪ The mesial aspect is very similar to the central INCISOR incisor with lessened dimensions. ▪ The contact area is also similar to the contact area of the central incisor, it is found in the incisal third very near the junction of the incisal and middle thirds. ▪ The cervical line exhibits less depth of curvature than it does on the mesial of the central incisors. DISTAL ASPECT: PERMANENT MAXILLARY LATERAL INCISOR ▪ Linguogingival Groove ▪ The distal surface is smaller and more convex in o is a more common finding in maxillary all dimensions than the mesial surface. lateral incisors than in central incisors. ▪ The contact area is shorter and not as incisally ▪ Lingual Pit placed, when compared to the mesial contact. It o Near the center of this groove, is also is normally located at the junction of the incisal more common. And when present, is a and middle thirds. potential site for caries. ▪ The cervical line shows less curvature incisally ▪ Linguogingival Fissure than on the mesial surface. o Another groove, which is sometimes found on the lateral bit very rarely on the central incisors. o This groove usually originates in the lingual pit and extends cervically, and slightly distally, onto the cingulum. POOF NICERIO, RAFFY 3  PERMANENT MAXILLARY AND MANDIBULAR LATERAL INCISORS INCISAL ASPECT: PERMANENT MAXILLARY LATERAL ▪ The apex is relatively sharper than that of the INCISOR central, and apical third may be deflected, and if so it is most often toward the distal. ▪ In both cervical and midroot cross sections the outline is roughly ovoid, wider labiolingually than mesiodistally. VARIATIONS AND ANOMALIES: PERMANENT MAXILLARY LATERAL INCISOR ▪ From the incisal aspect, the lateral generally resembles the central incisor, except the cingulum is often more prominent. ▪ The lateral incisor also exhibits relatively more convexity labially and lingually than the central incisor, and its outline may approach the ▪ The incisal portion of the cingulum may exhibit a rhomboid appearance. tubercle. ▪ Tubercle ROOT: PERMANENT MAXILLARY LATERAL INCISOR o Rounded or pointed projections found on the crowns of teeth due to excessive enamel formations. o Tubercles are not a normal finding, although they are not rare. o They are also variable in size and shape, but are usually smaller than cusps. o Tubercles are often thought of as Minicusps, and their most likely location ▪ The lateral incisor root is single, and wider is on the lingual surface of maxillary labiolingually than mesiodistally. anterior teeth. ▪ In comparison to the central, the root is longer in o The Cusp of Carabelli, a tubercle, is a relation to the crown length. normal finding on the mesial part of the lingual surface of permanent maxillary ROOT: PERMANENT MAXILLARY LATERAL INCISOR first molars. ▪ Pegs Lateral o A diminutive peg-shaped crown form, which is relatively common. And is due IQ NICERIO, RAFFY 4  PERMANENT MAXILLARY AND MANDIBULAR LATERAL INCISORS to lack of development of the mesial and exfoliation and often contact is shared distal portions of the crown. with the permanent canine. UNIVERSAL NUMBER ▪ Mandibular Right Lateral Incisor - #26 ▪ Mandibular Left Lateral Incisor - #23 FDI ▪ Mandibular Right Lateral Incisor - 42 ▪ Maxillary laterals sometimes are congenitally ▪ Mandibular Left Lateral Incisor – 32 mission. I.E: tooth buds do not form (agenesis). PALMER ▪ Mandibular Right Incisor - ▪ Mandibular Left Incisor - GENERAL FORM AND FUNCTION ▪ The mandibular lateral incisor is slightly larger in all aspects than the mandibular central incisor, but otherwise parallel is very closer in form. ▪ It also compliments the central in function. ▪ The lingualpit of the maxillary lateral maybe the DEVELOPMENTAL TABLE: PERMANENT MANDIBULAR entrance site where - enamel and dentin have LATERAL INCISOR become invaginated in the totth’s pulp cavity. Due to a developmental aberrancy called “Dens” Initiation of Calcification 3-4 months in dente. Completion of Enamel 4-5 years Eruption 7-8 years PERMANENT MANDIBULAR LATERAL INCISOR Completion of Root 10 years LABIAL ASPECT: PERMANENT MANDIBULAR LATERAL INCISOR GENERAL CHARACTERISTICS ▪ Arch Position o The mandibular lateral incisor is the ▪ The incisal margin may slope slightly gingivally second tooth from the midline in each toward the distal, which results in a distoincisal lower quadrant, and it shared a mesial angle that is more rounded than the same angle contact area with the central incisor. of the central incisor. o The distal contact is with the deciduous mandibular canine until that tooth’s As NICERIO, RAFFY 5  PERMANENT MAXILLARY AND MANDIBULAR LATERAL INCISORS ▪ This feature creates a slightly shorter distal MESIAL AND DISTAL ASPECT: PERMANENT margin, when compared to the mesial outline. MANDIBULAR LATERAL INCSIOR ▪ The contact area on the distal is more cervically ▪ The lateral’s distal surface is slightly shorter located than on the mesial, thus cervically incisocervically than the mesial surface. located height of contour on the distal outline. ▪ Both cervical line curvatures are slightly less ▪ Both heights of contour are still in the incisal than their counterparts in the central, and as third. would be expected , the mesial cervical line LINGUAL ASPECT: PERMANENT MANDIBULAR LATERAL shows greater incisal curvature than does the INCISOR distal. ▪ The Distal contact area, and hence the height of contour, is more cervically located than on the mesial. ▪ Although still in the incisal third, the distal contact area is very near the junction of the incisal and middle thirds, and is the most cervically located of any mandibular incisor contact. ▪ The lingual outlines are similar to those of the labial aspect. ▪ The structures of the lingual surface are similar to their counter - parts on the central incisor. Except the cingulum is more offset to the distal, and as a result the curvature of the cervical line is also offset distally. - NICERIO, RAFFY 6  PERMANENT MAXILLARY AND MANDIBULAR LATERAL INCISORS ROOT: PERMANENT MANDIBULAR LATERAL INCISOR ▪ Root length is normally a little greater than in the ▪ The distal contact area, and hence the height of central incisor. contour, is more cervically located than on the ▪ The root is also slightly thicker and wider. ▪ Root concavities maybe found on the mesial and mesial. distal root surfaces, and if present, the concavity INCISAL ASPECT: PERMANENT MANDIBULAR LATERAL in the distal is usually more pronounced. INCISOR VARIATIONS AND ANOMALIES: MANDIBULAR PERMANENT LATERAL INCISOR ▪ From this view, the incisal edge is not straight mesiodistally, as it is in the central; rather it curves toward the lingual in its distal portion. ▪ Furthermore, the lingual contour (cingulum) appears displaced toward the distal ▪ Anomalies are rare, but occasionally a bifurcated root is found. - NICERIO, RAFFY 7  ORAL ANATOMY ANF OCCLUSION: MAXILLARY AND MANDIBULAR CANINES CANINES d. The root is longer, and the combined crown plus root length is greater in the canine.  Are the most important teeth in the mouth. e. The cingulum shows greater development, and it  Cornerstone of the mouth is a much stronger tooth than the central incisor.  Main function is mainly for tearing and facial f. The middle labial lobe of the canine is much support. better developed, which is partially responsible  Canine’s form is wedge-like. for the greater convexity of the canine’s facial  Canine is in the cornerstone part of the mouth. surface.  Firmly anchored in the alveolar bone. PERMANENT MAXILLARY CANINE GENERAL CHARACTERISTICS: MAXILLARY CANINE a. Arch Position o The permanent maxillary canine replaces the deciduous maxillary canine and is located third from the midline in each maxillary quadrant. b. Universal Number o Maxillary right canine - #6 DEVELOPMENT TABLE OF MAXILLARY CANINE o Maxillary left canine - #11 c. General Form and Function Initiation of 4-5 months o The canine’s function in mastication is Calcification mainly tearing and piercing and they also Completion of 6-7 years function in aesthetics and speech. Enamel Eruption 11-12 years COMPARISONS TO THE MAXILLARY CENTRAL INCISOR Completion of Root 13-15 years LABIAL ASPECT: MAXILLARY CANINE a. Incisogingivally, the crown length is about the same, or even slightly shorter, than that of the central incisor. b. Mesiodistally, the canine crown is noticeably narrower. c. Labiolingually, the crown is considerably wider  The labial surface is convex in all directions, but than that of the central incisor. the curvature is more pronounced mesiodistally. _ NICERIO, RAFFY 1  ORAL ANATOMY ANF OCCLUSION: MAXILLARY AND MANDIBULAR CANINES  Mesial Outline  Between these ridges and cingulum are the two o The mesial margin is usually convex shallow concavities called the “Mesial Lingual from the mesial contact area to the Fossa” and Distal Lingual Fossa”. cervical line, with a rounded mesioincisal angle.  Distal Margin o The distal margin is shorter than the mesial margin and is usually concave between the distal contact area and the cervical line.  Incisal Margin o The incisal margin is divided into two components by the tip cusp, and they are termed the “Mesioincisal and Distoincisal Slopes”.  Cervical Outline o The CEJ is quite evenly curved toward the root. LINGUAL ASPECT: MAXILLARY CANINE MESIAL ASPECT: MAXILLARY CANINE  Mesial, distal, and incisal outlines  General considerations o These margins are like those of the labial o the mesial surface ins convex in all aspect. dimensions and is wider labiolingually  Cervical outline than the mesial surface of any of the o The cervical line curves asymmetrically incisors. toward the apex with a slight offset to o like other anterior teeth, it is triangular in the distal shape.  5 ridges in the lingual aspect:  Labial outline 1. 2 cuspal ridges o The labial margin is convex 2. 2 marginal ridges incisocervically, with the crest of 3. 1 lingual ridge curvature in the cervical third. F- NICERIO, RAFFY 2  ORAL ANATOMY ANF OCCLUSION: MAXILLARY AND MANDIBULAR CANINES  Lingual outline  The height of contour is located at a more o the lingual outline is concave in the cervical level and is associated with the contact incisal half, and convex in the cingulum area in the middle third. area, or gingival half, but less so than on INCISAL ASPECT: MAXILLARY CANINE incisor crowns because of the lingual ridge.  Cervical Outline o The cervical line is curved evenly toward the incisal, with the greatest extent of curvature directly beneath the incisal edge.  Incisal Outline o the incisal edge is thick, and from this  From the incisal, the maxillary canine is generally aspect, has an outline which slopes from convex in both its labial and lingual outlines. labial to lingual, like the maxillary  From the aspect, the canine crown has an incisors. asymmetrical diamond shaped outline.  Other Considerations  The mesial half is thicker labiolingually and more o The contact area is located at the convex, while the distal portion is thinner and junction of the middle and incisal third, exhibits a slightly concavity in its labial an/or about the midway between the labial and lingual outline. lingual surface.  The cingulum is offset to the distal from this view. DISTAL ASPECT: MAXILLARY CANINE  The greater development of the middle labial lobe is also evident from the incisal aspect and contributes to the increased convexity of the labial outline, when compared to the maxillary incisors. ROOT: MAXILLARY CANINE  The distal surface is generally smaller, with resultant shorter labial and lingual margins.  The cervical margin exhibits less curvature incisally than it does on the mesial surface.  the root is single, and normally the longest root  The lingual outline of the distal marginal ridge is of any tooth in the mouth. like to be more irregular than the outline of the  From all aspects, the root tapers gradually to a mesial marginal ridges. sharp or slightly blunted apex.  The contact area is more circular than on the  The root is generally wider labiolingually than mesial, and is located at a more cervical level mesiodistally. which is in the middle third.  Both lingual and labial surfaces are convex, while  A concavity is usually present in the cervical half the mesial and distal surfaces are convex or of the distal surface. slightly flattened. - NICERIO, RAFFY 3  ORAL ANATOMY ANF OCCLUSION: MAXILLARY AND MANDIBULAR CANINES  Cusp of mandibular canine also not so well VARIATIONS AND ANOMLAIES: MAXILLARY CANINE developed, not its tip normally as sharp mesiodistally. 1. Crown forms does not vary widely, although the  Labial surface not so convex. sharpness of the cusp tip has considerable DEVELOPMENT TABLE: MANDIBULAR CANINE range. 2. On rare occasions, the lingual surface may Initiation of 4-5 months exhibit a tubercle which is located near the most Calcification incisal level of the cingulum. Completion of 6-7 years 3. When a tubercle is present, a lingual pit is often Enamel associated with it. Eruption 9-10 years 4. Root form is subject to variations. There may be Completion of Root 12-14 years several curvatures along its length. It curved in LABIAL ASPECT: MANDIBULAR CANINE the apical third, the deflections is most commonly to the distal. 5. Since the maxillary canine normally erupts after the maxillary premolars, its space is sometimes partially closed. 6. It may then erupt to the labial or lingual of the other teeth, or not erupt at all, in which case it is impacted. PERMANENT MANDIBULAR CANINES GENERAL CHARACTERISTICS: MANDIBULAR CANINE a. Arch Position o 3rd tooth from the midline in each lower quadrant and is the replacement for the  General Considerations deciduous mandibular canine. o Pentagonal, like the maxillary canine. b. Universal Number o Labial surface is generally not so convex o Mandibular Right Canine - #27 but is generally more convex than the o Mandibular Left Canine - #22 mandibular incisors. c. General Form and Function  Mesial Outline o Similar to maxillary canine. o A straight line from the mesial contact to o For tearing, cosmetics, facial support, the cervical line. With a straight line from and phonetics. the mesial contact to the cervical line, Comparisons with the Maxillary Canine with an obtuse mesioincisal angle.  Crown is long, or longer Incisogingivally. o Crest of curvature of this margin near  Mesiodistal and labiolingual dimensions of crown the mesioincisal angle and is associated and root are usually less. with the contact area the incisal third.  Root usually shorter, sometimes may be as long.  Distal Outline  Total crown plus root length is approximately the o Outline is convex incisocervically, with a same for the two canines. more rounded Distoincisal angle.  Lingual surfaces and its structures are less well o Distal margin is shorter than mesial developed. margin. to NICERIO, RAFFY 4  ORAL ANATOMY ANF OCCLUSION: MAXILLARY AND MANDIBULAR CANINES o Height of contour is more cervically LINGUAL ASPECT: MANDIBULAR CANINE located than on the mesial outline.  Incisal Outline o The cusp is not as long, or the tip is not as sharp as the maxillary. o Distoincisal slope is normally longer and  Mesial, Distal, and Incisal Outlines its angulation cervically is steeper. o Mimic those of the labial aspect.  Cervical Outline  Cervical Margin o cervical line is evenly curved towards the o The cervical line shows a greater depth root. of curvature than on the labial. o Uneven, with the greatest curvature offset to the distal.  Other Considerations o Lingual surface is generally smoother and lacking in anatomic detail. o Cingulum does not extend so far incisally, and the marginal ridges are not so prominent. o Normally, there is a less pronounced lingual ridge, and shallow distolingual and mesiolingual fossae in the incisal  Other Considerations portion. o labial surface appears to be much longer o There are rarely any grooves, pits, or incisocervically than the maxillary tubercles. canine, it is long or slightly longer. o Lingual surface is slightly narrower o Labial ridge is not as prominent, mesiodistally than the labial aspect. developmental depressions are present, o Lingual height of contour is associated but imbrication lines are normally with the greatest prominence of the absent. cingulum in the cervical third. Iff NICERIO, RAFFY 5  ORAL ANATOMY ANF OCCLUSION: MAXILLARY AND MANDIBULAR CANINES MESIAL ASPECT: MANDIBULAR CANINE INCISAL ASPECT: MANDIBULAR CANINE  The mesial surface is roughly triangular in shape like the maxillary canine, but noticeably narrower labiolingually.  The surface contour is basically convex labiolingually, but incisocervically there is usually a flattening between the cervical line and the contact area.  Mandibular tooth is similar to the maxillary  The contact area is located in the incisal third, canine, when viewed from the incisal aspect. about midway between the labial and lingual  Mesiodistally, maxillary canine is wider than the surfaces. mandibular.  It is ovoid, and wider Incisogingivally than ROOT: MANDIBULAR CANINE labiolingually. DISTAL ASPECT: MANDIBULAR CANINE  the root is normally single, straight, and the  The contact area, and thus the height of contour, longest root in the mandibular arch. are found at a more cervical level at the junction of the incisal and middle thirds.  It also has a different outline which approaches a circular shape.  There is no incisocervical flattening on the distal surface, as there is on the mesial surface. - NICERIO, RAFFY 6  ORAL ANATOMY ANF OCCLUSION: MAXILLARY AND MANDIBULAR CANINES VARIATIONS AND ANOMALIES: MANDIBULAR AND  The CEJ of canine is quite evenly curved toward MAXILLARY CANINES the root.  The lingual outline is quite evenly curved  Crown form is not greatly variable. towards the root.  Irregularly curved roots are occasionally seen,  The lingual outline is concave in the incisal half and bifurcated roots, with labial and lingual and convex in cingulum, except the cingulum in branches, are also possible. mandibular canine is less prominent.  The distal surface is similar to the mesial surface, except it is small in all dimensions. SUMMARY  Canines are located at the third from the midline in upper and lower quadrant.  Shares mesial contact with the lateral incisor and distal contact with the first premolars.  Functions to tearing, piercing esthetics, and speech.  The crown form viewed from the labial or lingual aspect are pentagonal and is bulky in comparison with the incisors.  The root of maxillary canine is longer and greater when combined with the crown length while the mandibular canine is shorter.  The lingual surface is less developed in mandibula canine than in maxillary canine.  The general outline of both the maxillary and mandibular canine are pentagonal.  Maxillary canine labial surface is convex in all direction, but not so much for mandibular canine.  The mesial margin from mesial contact area to cervical line in maxillary canine is usually convex, whereas the mandibular is straight line.  The distal margin in both maxillary and mandibular are shorter than the mesial margin. _ NICERIO, RAFFY 7  MAXILLARY ST 1 PREMOLAR UNIQUE CHARACTERISTICS Largest of all premolars CROWN MORPHOLOGY Has prominent buccal ridge Only permanent tooth with mesial cusp ridge> distal ridge Has a prominent mesial marginal ridge groove, which can make scaling difficult OCCLUSAL MORPHOLOGY Occlusal shape is hexagonal; proximal shape is trapezoidal Occlusal table has long central groove with fewer supplemental grooves No central pit, but has mesial and distal pits 2 cusps: buccal (slightly distal), palatal (slightly mesial) Buccal cusp height> palatal ROOT MORPHOLOGY Only premolar with two roots (B>P) Has prominent mesial root concavity Sits most vertically (B-L) in alveolar bone OCCLUSAL CONTACTS Occludes with mandibular 1st and 2nd premolars MANDIBULAR ST 1 PREMOLAR UNIQUE CHARACTERISTICS Smallest of all premolars CROWN MORPHOLOGY Has prominent mesio-lingual groove MMRmesial cusp ridge Has buccal ridge, but not as prominent as 1st premolar OCCLUSAL MORPHOLOGY Occlusal shape is hexagonal; proximal shape is trapezoidal Occlusal table is more ovoid and symmetrical than maxillary 1st premolar Occlusal table has short central groove with more supplemental grooves. Has a WRINKLED appearance 2 cusps: buccal, palatal (slightly mesial) Buccal cusp height = palatal ROOT MORPHOLOGY Only premolar without a mesial root depression OCCLUSAL CONTACTS Occludes with mandibular 2nd premolar and 1st molar  MANDIBULAR ND 2 PREMOLAR UNIQUE CHARACTERISTICS Most congenitally missing premolar The gingival papilla between the 1st and 2nd premolar is the shortest CROWN MORPHOLOGY Lingual surface is wider (M-D) than that of the mandibular 1st premolar Shorter and wider than the mandibular 1st premolar (from buccal) Mesial marginal ridge has slight concavity Only premolar with five lobes: 3 buccal and 2 lingual OCCLUSAL MORPHOLOGY Occlusal shape is square, proximal shape is rhomboidal (tilted lingually Occlusal surface can have three configurations: Y (most common configuration): 3 cusps- buccal > ML> DL with a single central pit H : 2 cusps- buccal and lingual with short central groove\ U : 2 cusps- buccal and lingual with crescent-shaped central groove\ Buccal cusp is shorter and blunter than lingual cusps ML cusp is larger than the DL cusp Mesial marginal ridge has slight concavity ROOT MOPHOLOGY Root is longer than the mandibular 1st premolar Apex closet to mental foramen OCCLUSAL CONTACTS Occludes with maxillary 1st and 2nd premolars MAXILLARY ST 1 MOLAR UNIQUE CHARACTERISTICS Largest permanent tooth Only tooth that is broader lingually than buccally Widest tooth (B-L) First permanent maxillary tooth to erupt CROWN MORPHOLOGY Only tooth with a pronounced distal concavity at the CEJ, which can make scaling difficult Has a long buccal groove with a central pit Has a distolingual groove with a pit (on all maxillary molars) OCCLUSAL MORPHOLOGY Occlusal shape is rhomboidal, proximal shape is trapezoidal 4 cusps: MB, ML (largest), DB, DL(smallest) Sometimes has a 5th cusp of Carabelli lingual to ML cusp Primary cusp triangle: formed by ML, MB, and DB cusps (same for all maxillary molars) Secondary cusp triangle: formed by DL cusp Cusp heights: ML>MB>DB (primary cusp triangle)>DL (secondary cusp triangle)> Carabelli Only tooth with 2 triangular ridges on one cusp (ML cusp): from the transverse and oblique ridges Has most prominent oblique ridge of all maxillary molars Transverse groove of the oblique ridge connects the central and distal fossae (same for all maxillary molars) ROOT MORPHOLOGY 3 roots MB, DB (shortest) palatal (longest) Apices are closest to maxillary sinus MB and DB roots are often shaped like “plier handles” MB root has more common (94%) and deeper(0.3mm) concavities than other roots OCCLUSAL CONTACTS Occludes with mandibular 1st and 2nd molars MANDIBULAR ST 1 MOLAR UNIQUE CHARACTERISTICS Largest mandibular tooth Widest tooth (M-D) First permanent tooth to erupt, and most often restored/ extracted CROWN MORPHOLOGY Can see all 5 cusps from buccal Buccal cusps are shorter and blunter than the lingual cusps OCCLUSAL MORPHOLOGY Occlusal shape is pentagonal, proximal shape rhomboidal (tilted lingually 15-20°) 5 cusps: MB (largest), DB, distal (smallest), ML (tallest), DL. Occlusal pattern resembles a “+ DB cusp Has an irregular groove pattern ROOT MORPHOLOGY Roots are usually short, distally inclined, and often fused Typically has distally inclined root trunk and apices OCCLUSAL CONTACTS Occludes with maxillary 2nd and 3rd molar  ORAL ANATOMY AND OCCLUSION: PERMANENT MAXILLARY AND MANDIBULAR THIRD MOLARS PERMANENT MAXILLARY THIRD MOLAR  Permanent Maxillary left third molar -  Deciduous Maxillary right molar -  Deciduous Maxillary left molar - GENERAL CHARACTERISTICS GENERAL FORM AND FUNCTION  The crown of the third molar is generally smaller in all dimensions than the second molar.  It exhibits more rounding.  Normally the smallest molar in the oral cavity.  The most variable tooth in the maxillary arch.  The most common occlusal form is similar to heart-shaped second molar.  The roots are normally shorter than those of the second molar and are often partially, or fully fused.  Third molars are abnormally erupted to the lack  For grinding food. of space on the alveolar processes of both DEVELOPMENTAL TABLE (MAXILLARY) maxillary and mandibular bone.  Classification of angular eruption: Vertical, Initiation of Calcification 7-9 years Mesioangular, and Distoangular. Completion of Enamel 12-16 years  Third molar can cause Discomfort when its Eruption 17-21 years erupting. Completion of Root 18-25 years ARCH POSITION CROWN FORM (MAXILLARY)  The upper third molar is located eight and last from the midline of each maxillary quadrant of  When compared to the second molar, the crown the permanent dentition. is smaller in all dimensions, especially  This tooth has a mesial contact with the occlusocervically and mesiodistally. permanent 2nd Molar, and no distal contact.  This tooth varies so greatly that it is difficult to  It is not a succedaneous tooth. describe a standard, or typical third molar. UNIVERSAL NUMBER (DECIDUOUS, PERMANENT)  The distolingual cusp is greatly diminished in size or is absent, leaving only three functional  Permanent Maxillary right third molar - cusps, and in many cases no distolingual  Permanent Maxillary left third molar - groove.  Deciduous Maxillary right third molar -  The groove pattern is variable, and often reveals  Deciduous Maxillary left third molar - many supplemental grooves. FDI NUMBER (DECIDUOUS, PERMANENT)  Despite the variability in crown form, maxillary third molar specimens are always wider  Permanent Maxillary right third molar - buccolingually than mesiodistally.  Permanent Maxillary left third molar -  Deciduous Maxillary right third molar -  Deciduous maxillary left third molar - PALMER’S NUMBER  Permanent Maxillary right third molar - TEE NICERIO, RAFFY 1  ORAL ANATOMY AND OCCLUSION: PERMANENT MAXILLARY AND MANDIBULAR THIRD MOLARS ROOT FORM (MAXILLARY)  Like crown form, root numbers and morphology are extremely variable.  Root dimensions are normally the smallest of any maxillary molar.  The most common root type, usually in conjunction with the heart-shaped crown form, is three roots, which are often partially or wholly fused together. VARIATIONS AND ANOMALIES (MAXILLARY)  This tooth exhibits the most divergence in crown and root form of any maxillary tooth.  The crown varies in size from a simple, and tiny one cusp form, which is often devoid of grooves and pits.  Is known as a peg third mola, to a large crown with numerous cusps, or tubercles, and an deflections at odd angles are common.  Third molars of both arches are often congenitally missing (oligodontia) or impacted.  Supernumerary Teeth – although are rare, supernumerary (extra teeth) are sometimes found just distal to the third molar area. When present, they are usually impacted.  Supernumerary teeth is caused by the condition called Hyperdontia, is the condition of having supernumerary teeth, or teeth that appear in addition to regular number of teeth.  Crown anomalies are uncommon, although five- cusp specimens are occasionally seen.  Root anomalies are more common, and may be manifested in fused root or irregular curvatures. TYPES OF CUSP FORM (MAXILLARY) - NICERIO, RAFFY 2  ORAL ANATOMY AND OCCLUSION: PERMANENT MAXILLARY AND MANDIBULAR THIRD MOLARS PERMANENT MANDIBULAR THIRD MOLAR third molars can range from very small to much larger than any other molar.  When third molars do vary greatly from normal GENERAL CHARACTERISTICS size, it is more common to find extra large mandibular third molars, and extra small maxillary third molars. ARCH POSITION (MANDIBULAR) DEVELOPMENTAL TABLE (MANDIBULAR)  The mandibular third molar occupies the eight, Initiation of 8-10 years and last, position from the midline in each Calcification mandibular quadrant. Completion of Enamel 12-16 years  The mesial contact is shared with the permanent second molar, and there is no distal contact. Eruption 17-21 years  It is also known as the “Lower Wisdom Tooth” Completion of Root 18-25 years UNIVERSAL NUMBER (DECIDUOUS, PERMANENT)  Permanent Mandibular right third molar -  Permanent Mandibular left third molar - CROWN FORM (MANDIBULAR)  Deciduous Mandibular right third molar -  The crown form is so variable that only  Deciduous Mandibular left third molar - generalizations about two basic types will be FDI NUMBER (DECIDUOUS, PERMANENT) made. a. Type l – the type l crown resembles the  Permanent Mandibular right third molar - permanent second molar. It has four  Permanent Mandibular left third molar - cusps, and the same general contours  Deciduous Mandibular right third molar - and occlusal pattern.  Deciduous Mandibular left third molar - b. Type ll – this type resembles the PALMER’S NUMBER (DECIDUOUS, PERMANENT) permanent first molar with five cusps, a  Permanent Mandibular right third molar - similar occlusal pattern, and comparable  Permanent Mandibular left third molar - contours.  Deciduous Mandibular right molar -  Third molars normally exhibit many more  Deciduous Mandibular left third molar – secondary grooves on the occlusal table, and it is even sometimes difficult to identify the GENERAL FORM AND FUNCTION primary grooves.  The mandibular third molars are extremely  The most common third molar reveals a Type l variable in size and shape of both their crown crown in conjunction with two root branches. and root.  Other crown forms range from one-cusped  However, they have one feature which remains dwarfs to six-cusped specimens. constant in the midst of all the variations.  Almost always, the mesiodistal dimensions of the crown is greater than the buccolingual dimension, just the opposite of the maxillary third molar’s dimensions.  Ordinarily, the molars decrease in general size from first molar to third molar, but the crowns of &NICERIO, RAFFY 3  ORAL ANATOMY AND OCCLUSION: PERMANENT MAXILLARY AND MANDIBULAR THIRD MOLARS ROOTS (MANDIBULAR)  Roots are also extremely variable in numbers, size, and curvatures.  Single fused roots are common, as are two- rooted specimens to other mandibular molars.  There may be as many as eight roots, and curvatures, and fusions, or partial fusions, run the gamut.  Most often, root length is less than with other mandibular molars, regardless of the crown size. The most common root form reveals two short root branches. VARIATIONS AND ANOMALIES (MANDIBULAR)  Third molars are often congenitally missing or impacted.  The area immediately distal to the third molar may be the site of supernumerary teeth. When present, they are normally impacted.  Many of the numerous anomalies have been previously, but almost structural anomaly conceivable is possible in third molars. TYPE OF CUSP FORM (MANDIBULAR) - GOODLUCK! NICERIO, RAFFY 4