Permanent Canines PDF

Permanent Canin. (Maxillar y & Mandibular) By Mabroukah Imbarak  The contents: The general features of permanent canines. Their importance in the mouth. The chronology of permanent canines. Permanent Maxillary Canine. Crown and Root surfaces from all aspects: Labi...

Permanent Canin. (Maxillar y & Mandibular) By Mabroukah Imbarak  The contents: The general features of permanent canines. Their importance in the mouth. The chronology of permanent canines. Permanent Maxillary Canine. Crown and Root surfaces from all aspects: Labial aspect Lingual aspect Incisal aspect Mesial aspect Distal aspect Permanent Mandibular Canine. Crown and Root surfaces from all aspects: Labial aspect Lingual aspect Incisal aspect Mesial aspect Distal aspect The differences between maxillary and mandibular permanent canines.  The general features: The canines are the third teeth from the midline (Anterior teeth). They are 4 in number (2 maxillary & 2 mandibular), one in each side of the jaw. The four canines are placed at the corners of the mouth. They are called cornerstone of the dental arches. The maxillary and mandibular canines have a close resemblance to each other, and their functions are closely related. Each of them has a single cusp and a single root. They are the longest teeth in the mouth. Their middle labial lobes have been highly developed incisally into well-formed cusps and labially into labial ridges. Their main function to support the incisors and premolars, since they are located between these groups ( tearing the food).  The importance of the permanent canines Esthetic: They have anchorage in the bone, along with the bone ridge over the labial portions of the roots, called the “canine eminence”, have a cosmetic value. ( they give support to the facial muscles that ensures normal facial expression at the “corners” of the mouth ). Stability: they are the most stable teeth so they are very important as an assistant in stabilizing the dental arch.  The chronology Maxillary permanent Canine Mandibular permanent Canine First evident of First evident of calcification 4 -5 months calcification 4 -5 months Enamel completed 6 – 7 years Enamel completed 6 -7 years Eruption 11 – 12 years Eruption 9 -10 years Root completed 14 -15 years Root completed 12 – 13 years Maxillary Canine  Maxillary Canine Relation  The mesial surface of the crown : contact with the distal side of lateral incisor (at the junction between incisal & middle third).  The distal surface of crown : 1 contacts the mesial side of first premolar (at the middle of the 3 2 middle third). 4  Therefore, the contact areas of the maxillary canine are at different levels cervicoincisally.  Labial : Crown Geometrical shape of crown : Trapezoidal with short arm at cervix. D M Mesial outline : convex from the cervical line to the contact area. Mesial contact area : at the junction of the middle & incisal thirds. Distal outline : concave from the cervical line to the contact area. Distal contact area : at the center of the middle third. M D  Labial : Crown The cusp tip is on a line with the center of the root or sometimes slightly mesially placed. D M The cusp has mesial slope and distal slope, the distal slope is longer than the mesial slope. Both slopes show a tendency toward concavity before wear has taken place. The cervical Line is convex root wise  Labial : Crown The crown labial surface: The crown surface is convex with maximum convexity at cervical 1/3 representing D M cervical ridge. The middle lobe is prominent buccally forming labial ridge. There are two developmental depressions (Mesial & Distal) to the labial ridge.  Labial : Root The root of maxillary canine long, slender, conical in shape. D M a bluntly pointed apex. distal curvature of its apical third. The labial surface of the root: is smooth and convex at all points.  Lingual : Crown The crown and root are narrower lingually than labially (The tooth tapers lingually). The cervical line from this aspect shows a more even curvature. M D The cingulum is large, and in some instances is pointed like a small cusp. There is a well-developed lingual ridge extends from the cingulum to the cusp tip. There are shallow concavities between this ridge and marginal ridges, they are called mesial and distal lingual fossae.  Lingual : Root M D The root of maxillary canine is narrower lingually than labially it is smooth and convex at all points from the cervical line to the apical end.  Mesial : Crown The geometrical outline of crown: Triangular or wedge shape with its base cervically and its tip represented by the tip of B L the cusp. It shows greater labiolingual measurement than any of the other anterior teeth. The cervical line is concave root-wise with approximately 2.5 mm in depth.  Mesial : Crown The crest of curvatures labially and lingually are present at the junction between the B L cervical and middle third (the same level). The labial outline: The labial outline is convex from cervical line to the crest of curvature, this convexity is called cervical ridge. From the crest of curvature at the cervical third to tip of the cusp the labial outline is slightly convex or straight.  Mesial : Crown The lingual outline: The lingual outline is convex describing the cingulum. B L The outline become straight or slightly concave at the middle third, then becoming convex again at the incisal third.  Mesial : Crown The mesial surface of the crown Mesial contact area is at the junction of incisal and middle thirds. B L The mesial surface of the crown has convexities at all points except area above the contact area where the surface is concave and flat. Tip of cusp is even labial on long axis of the tooth.  Mesial : Root Root is conical with blunt apex and may be curved labially. B L The root surface appears broad with a shallow developmental depression. Developmental depressions on the heavy roots help to anchor the teeth in the alveoli and help to prevent rotation and displacement.  Distal : The distal aspect of the maxillary canine shows somewhat the same form as the mesial aspect, with the following variations : Variations: Cervical Line is less curved. L L Distal marginal ridge is heavier & more irregular. B Contact area is more cervically and the surface above it is more concave. Root developmental Depression is more prominent.  Incisal : Crown B B The labio- lingual dimension is greater than the mesiodistal. The tip of the cusp is labial to the center of the crown labio lingually and mesial to the D M center mesiodistally Mesial cusp slope < Distal cusp slope. The labial surface is convex. L L The crown of this tooth gives the impression of having the entire distal portion stretched to make contact with the first premolar.  Incisal : Crown B All elevations and depressions can be seen from this aspect. The ridge of the middle labial lobe is very noticeable labially from the incisal aspect. It attains its greatest convexity at the cervical third of the crown, becoming broader and flatter at the middle and incisal thirds The cingulum development makes up the cervical third of the crown lingually. Mandibular Canine  Mandibular Canine Relation  The mesial surface of the crown : contact with the distal side of lateral incisor (at the incisal third just below the mesioincisal angle ).  The distal surface of crown : 2 3 4 1 contacts the mesial side of first premolar (at the junction between the middle and incisal thirds, more cervically located than the mesial contact area).  Labial aspect. Crown Differ from Maxillary canine that: Narrower Mesiodistally (about 0.5mm). Crown longer by 1mm. D M Mesial outline: it is nearly straight with the mesial surface of the root, with the contact area being near the mesio-incisal angle. Distal outline: slightly concave in the cervical third then convex, contact more cervical than mesial. The Mesial & Distal Contact Area is more incisally than those of maxillary canine. Cervical Line: more symmetrically (semicircular curvature apically). The labial ridge is not as well developed as that of a maxillary canine.  Labial aspect. Crown The cusp tip is usually on the root axis line. Its slopes form amore obtuse angle than those of upper canine. The cusp is less pointed than that of upper canine. D M Root The root is shorter than that of the upper canine by 0.6 mm to 2 mm. Its apical end is more sharply pointed. Its apical end is more often straight than curving toward mesial or distal sides. The root is convex on the labial surface.  Lingual aspect. Crown The crown taper toward the lingual surface. The lingual surface of the crown resembles those of the lower incisors in being smooth, M D However; A faint lingual ridge is running from the cusp tip to the cingulum. The cingulum is poorly developed. The marginal ridges are not prominent. The mesial marginal ridge is longer and straighter than the shorter,more elevated and curved distal marginal ridge.  Lingual aspect. Root The lingual portion of the root is narrower than that of the upper canine. The lingual surface of the root is convex, M D smooth and regular.  Mesial aspect. Crown The cusp appears more pointed. The cusp tip of mandibular canine placed on B L the line of the center of the root or lies lingually. Cervical line curves more incisally than does the cervical line on upper canine. Labial outline of mandibular outline is less curved whereas the lingual outline is curved in the same manner as that of maxillary canines.  Mesial aspect. Crown The labial outline has less curvature than that of upper canine with very little crest of curvature directly above the cervical line. The lingual outline is similar to that of the upper B L canine. The cingulum is not prominent. The incisal portion of the crown is thinner labiolingually.  Mesial aspect. Root The root surface is similar to that of the upper canine from the mesial aspect except: The root tip is more pointed than that of B L upper canine. The developmental depression mesially is more pronounced than that on upper canine. A variation in the form of the mandibular canine is bifurcated roots ( rare).  Distal aspect. Distal Marginal Ridge is more pronounced than that of upper canine. The distoincisal angle is slightly more lingual B in position than the cusp tip. L L Cervical Line is less curved than that of upper canine. Distal contact area more cervically. Developmental depression on the root is more pronounced than that of upper canine.  Incisal aspect. L The outline of lower canine from the incisal aspect is often similar to that of upper canine. The labiolingual dimension of the crown is longer than the mesiodistal dimension similar to upper canine. The cusp tip is more likely to be inclined lingually. D M Labially, the mesiolabial outline is more convex while the disto-labial outline is flat or concave The distal cusp slope is directed slightly lingually from the cusp tip, which places the distoincisal angle in a lingual position to the cusp tip. B  Perm Maxillary Mandibular Than. Mabroukah Imbarak