MANDIBULAR FIRST BICUSPID

Facial: The outline is very nearly symmetrical bilaterally, displaying a large, pointed buccal cusp. From it descends a large, well developed buccal ridge.

Lingual: This tooth has the smallest and most ill-defined lingual cusp of any of the premolars. A distinctive feature is the mesiolingual developmental groove

Proximal: The large buccal cusp tip is centered over the root tip, about at the long axis of this tooth. The very large buccal cusp and much reduced lingual cusp are very evident. You should keep in mind that the mesial marginal ridge is more cervical than the distal contact ridge; each anticipate the shape of their respective adjacent teeth.

Occlusal: The occlusal outline is diamond-shaped. The large buccal cusp dominates the occlusal surface. Marginal ridges are well developed and the mesiolingual developmental groove is consistently present. There are mesial and distal fossae with pits,

Contact Points: When viewed from the facial, each contact area/height of curvature is at about the same height.

Root Surface:-The root of the mandibular first bicuspid is usually single, but on occasion can be bifurcated (two roots).

MAXILLARY CUSPIDS (CANINE)

The maxillary cuspid is usually the longest tooth in either jaw. canines are considered the corner stones of the dental arch They are the only teeth in the dentition with a single cusp.

Facial Surface:- The facial surface of the crown differs considerably from that of the maxillary central or lateral incisors. In that the incisal edges of the central and lateral incisor are nearly straight, the cuspid has a definite point, or cusp.  There are two cutting edges, the mesioincisal and the distoincisal. The distoincisal cutting edge is the longer of the two. The developmental grooves prominent on the facial surface  extending two-thirds of the distance from the tip of the cusp to the cervical line.  The distal cusp ridge is longer than the mesial cusp ridge

Lingual Surface:  Distinct mesial and distal marginal ridges, a well-devloped cingulum, and the cusp ridges form the boundries of the lingual surface. The prominent lingual ridge extends from the cusp tip to the cingulum, dividing the lingual surface into mesial and distal fossae.

Proximal: The mesial and distal aspects present a triangular outline. They resemble the incisors, but are more robust--especially in the cingulum region

Incisal: The asymmetry of this tooth is readily apparent from this aspect. It usually thicker labiolingually than it is mesiodistally. The tip of the cusp is displaced labially and mesial to the central long axis of this tooth.

Root Surface:-The root is single and is the longest root in the arch. It is usually twice the length of the crown.

MORPHOLOGY OF THE DECIDUOUS TEETH

Deciduous Anterior Teeth.

 -The primary anteriors are morphologically similar to the permanent anteriors.

-The incisors are relatively simple in their morphology.

-The roots are long and narrow.

-When compared to the permanent incisors, the mesiodistal dimension is relatively larger when compared to axial crown length

-At the time of eruption, mamelons are not present in deciduous incisors

-They are narrower mesiodistally than their permanent successors.

 lntraarch relationship refers to the alignment of the teeth within an arch

1. In an ideal alignment teeth should contact at their proximal crests of curvature. A continuous arch form is observed in occlusal view

Curves of the occlusal plane (a line connecting the cusp tips of the canines, premolars, and molars) are observed from the proximal view

Curve of Spee: anterior to posterior curve; for mandibular teeth the curve is concave and for maxillary teeth it is convex

Curve of Wilson- medial to lateral curve for mandibular teeth the curve is also convex and for the maxillary it is convex

2. Contact does not always exist Some permanent dentitions have normal spacing

Primary dentitions often have developmental spacing in the anterior area: some primary den titions have a pattern of spacing called primate spaces between the primary maxillary lateral incisors and canine and between the mandibular canine and first mo1ar

Disturbances to the intraarch alignment are described as

a. Qpen contact where interproximal space exist  because of missing teeth oral habits, dental disease, or overdeveloped frena

b. where contact or position is at an unexpected area because of developmental disturbances, crowding, dental caries or periodontal ligament for their misplaced position: facial, lingual. mesial, supra(supraerupted) infra (infraerupted) and torso (rotated) version