permanent anterior teeth
Overview
This chapter will teach you about the front teeth that stay in your mouth forever.
You will learn about their shapes, what they are used for, and important things dentists think about when looking at them.
Learning Objectives
You will learn how to describe the general and specific shapes of each permanent front tooth.
You will learn the job of your incisors, which are your front cutting teeth.
You will be able to name features that are common to all incisors.
You will learn to describe and point out the different sides of all front teeth: the front (labial), back (lingual), side closest to the middle (mesial), side farthest from the middle (distal), and the biting edge (incisal).
You will learn how to tell the difference between upper and lower front teeth based on where they are in your mouth.
You will understand important things dentists need to remember because of how your permanent front teeth are structured.
Anatomical Structure of Anterior Teeth
Classification of Anterior Teeth
Upper Front Teeth:
These include the Central Incisors, which are your two front teeth.
They also include the Lateral Incisors, which are next to the central incisors.
Lastly, they include the Canines, which are the pointy teeth on the corners of your mouth.
Lower Front Teeth:
These also include the Central Incisors, the two front teeth on the bottom.
They include the Lateral Incisors, located next to the lower central incisors.
And they include the Canines, your lower pointy corner teeth.
Developmental Lobes and Depressions
How All Front Teeth Develop (Developmental Lobes):
Each front tooth forms from four main parts, called lobes.
These lobes are the Mesiolabial Lobe (front-middle part), the Middle Labial Lobe (front-center part), the Distolabial Lobe (front-side part), and the Lingual Lobe (back part).
Shallow Grooves on Front Teeth (Developmental Depressions):
You can see two shallow vertical grooves on the front surface of these teeth.
These grooves are found between the lobes mentioned above.
They are called the Mesiolabial Developmental Depression and the Distolabial Developmental Depression.
General Features of Permanent Anterior Teeth
Chewing Surface: The biting or cutting edge of your front teeth is called the incisal surface. This is the main part they use for chewing.
Incisal Edge: This is the actual sharp ridge found on the incisal surface of the front teeth.
Bumps When Teeth First Erupt (Mamelons): When permanent front teeth first come through the gums, they often have small rounded bumps on their biting edge called mamelons. These bumps usually wear away as you use your teeth.
Crown Shape: If you look at a front tooth from the side, its main body (crown) has a triangular shape.
Tooth Size: Front teeth are typically wider from side to side (mesiodistally) than they are from front to back (labiolingually).
Height of Contour: This term refers to the highest or most bulging part of the tooth's curve.
Contact Area: This is the specific spot where one tooth touches its neighboring tooth on the side.
Lingual Surface Characteristics (Back Surface Features)
Cingulum: This is a raised, rounded bump located near the gum line on the back surface of front teeth. It corresponds to the lingual developmental lobe.
Marginal Ridge: These are rounded, raised borders found on the back surface of the tooth, running along the sides (mesial and distal).
Fossae: Some front teeth have shallow, wide dips or depressions on their back surface, which are called fossae.
Developmental Pits: Sometimes, you can find small, deep holes called developmental pits in the deepest part of these fossae.
Developmental Grooves: These are V-shaped lines that show where different developmental lobes of the tooth joined together.
Supplemental Groove: These are shallower and more irregular grooves that can also appear on the back surface of the tooth.
CEJ and Proximal Surface Features
Gum Line Curve (Cementoenamel Junction - CEJ): The line where the tooth's crown meets its root is called the CEJ. On the sides of front teeth, this curve is usually much deeper than on back teeth.
Small Ridges (Imbrication Lines): These are faint, small ridges that run horizontally across the front (labial) surface near the gum line, especially in the cervical third. The grooves between these ridges are called perikymata.
Permanent Maxillary Central Incisors (Your Upper Two Front Teeth)
Identification: These teeth are labeled as 8 and 9 in the Universal Numbering System.
Eruption Time: They typically erupt into the mouth when a child is between 7 and 8 years old.
Key Features:
These are the largest and widest front teeth in your mouth when measured from side to side.
They often show slight ridges (imbrication lines) and grooves (perikymata) near the gum line, particularly in the lower third of the crown.
The side of each central incisor closest to the middle (mesial surface) touches the mesial surface of the other central incisor at the biting edge area.
The side farthest from the middle (distal surface) touches the lateral incisor at the point where the biting edge area meets the middle of the tooth.
Ways to Tell Them Apart:
The corner of the tooth closest to the middle (mesioincisal angle) is usually sharp and straight.
The corner farther from the middle (distoincisal angle) is typically more rounded.
The curve of the gum line (CEJ) on the mesial side is much deeper than on the distal side.
Inside the Tooth (Pulp Cavity Structure):
Each tooth has a single, straight canal for the pulp (nerve and blood vessels).
The pulp chamber usually has three small extensions, called pulp horns, which match the three front-facing developmental lobes.
Root: The single root is shaped like a cone and is usually smooth, without any noticeable dips on its sides.
Lingual View of Maxillary Central Incisors (Looking at the Back Surface)
Cingulum: The bump near the gum line on the back surface is wide and well-developed.
Marginal Ridges: The raised border on the side closest to the middle (mesial marginal ridge) is typically longer than the one on the side farther from the middle (distal marginal ridge).
Lingoincisal Edge: The biting edge from the back perspective is usually level with the marginal ridges and has one shallow depression (fossa).
Permanent Maxillary Lateral Incisors (Upper Teeth Next to the Central Incisors)
Identification: These teeth are labeled as 7 and 10 in the Universal Numbering System.
Eruption Time: They usually come in between 8 and 9 years of age.
Key Features:
These teeth are smaller than the central incisors.
They have a very noticeable back surface (lingual surface).
The shallow grooves on the front surface and the small ridges near the gum line are less pronounced than on the central incisors.
The side closest to the middle (mesial surface) touches the central incisor in the biting edge area.
The side farthest from the middle (distal surface) touches the canine in the middle third of the tooth, or where the biting edge area meets the middle third.
Ways to Tell Them Apart:
The corner of the tooth closest to the middle (mesioincisal angle) is sharper than the corner farther from the middle (distoincisal angle).
The gum line curve (CEJ) on the mesial side is much more curved.
Inside the Tooth (Pulp Cavity Structure):
There is usually a single pulp canal.
The pulp chamber might be rounded or show two less-sharp pulp horns.
Root: The single root is cone-shaped and might curve slightly towards the side farthest from the middle (distal) with a pointed tip.
Lingual View of Maxillary Lateral Incisor (Looking at the Back Surface)
Cingulum: The bump near the gum line on the back surface is narrow but stands out, and it's usually centered.
Lingual Fossa: The depression on the back surface is deep and very noticeable, and the raised borders (marginal ridges) are prominent.
Lingual Groove: A groove can often be seen separating the cingulum from the deep depression (fossa). A small pit (lingual pit) might also be found within this groove.
Linguogingival Groove: Sometimes, a groove can extend from the lingual pit downwards towards the gum line and slightly towards the distal side of the cingulum. This specific groove is more common on lateral incisors than on central incisors.
Permanent Mandibular Central Incisors (Your Lower Two Front Teeth)
Identification: These teeth are labeled as 24 and 25 in the Universal Numbering System.
Eruption Time: They are usually the first permanent teeth to erupt, appearing between 6 and 7 years of age.
Key Features:
These are the smallest and simplest teeth in your mouth.
They are almost perfectly symmetrical on both sides.
The front surface (labial aspect) often looks like a fan.
Both the mesial and distal side surfaces touch adjacent teeth in the biting edge area.
Ways to Tell Them Apart:
The corner closest to the middle (mesioincisal angle) is sharper compared to the corner farther from the middle (distoincisal angle).
The gum line curve (CEJ) on the mesial side is very pronounced.
Inside the Tooth and Root Structure:
The small ridges (imbrication lines) and shallow grooves on the front surface are usually absent or very faint.
The back surface is smooth, with a small, centered bump (cingulum).
The raised borders (marginal ridges) and depressions (lingual fossa) on the back surface are very minimal.
Root: The tooth has a single root that is widest when measured from front to back. It has noticeable dips or curves on its side surfaces (proximal root concavities).
It typically has a single pulp canal with three pulp horns (extensions of the pulp chamber).
Permanent Mandibular Lateral Incisors (Lower Teeth Next to the Central Incisors)
Identification: These teeth are labeled as 23 and 26 in the Universal Numbering System.
Eruption Time: They typically erupt when a child is between 7 and 8 years old.
Key Features:
These teeth are slightly larger than the lower central incisors.
Their crowns often appear slightly tilted or twisted towards the side farthest from the middle (distal). The bump on the back surface (cingulum) is usually found a little to the distal side.
The raised borders (marginal ridges) are more developed, and the one on the side closest to the middle (mesial ridge) is longer.
Both the mesial and distal side surfaces touch adjacent teeth in the biting edge area.
Ways to Tell Them Apart:
The corner closest to the middle (mesioincisal angle) is sharper, while the corner farthest from the middle (distoincisal angle) is more rounded.
The gum line curve (CEJ) on the mesial side is more pronounced.
Root Structure:
The tooth has a single, straight root.
It has very noticeable dips or curves on its side surfaces (proximal root concavities), especially on the side farthest from the middle (distal side).
It contains a single pulp canal with three pulp horns.
Permanent Canines (Pointy Corner Teeth)
General Features:
These teeth are wider from front to back (labiolingually) compared to incisors.
Instead of a straight biting edge, they have a single point called a cusp tip, with two sloping edges leading away from it. The slope towards the middle (mesial cusp slope) is usually shorter than the slope towards the side (distal cusp slope).
A prominent ridge runs down the front surface (labial ridge), formed because the middle front developmental lobe is exceptionally well-developed.
Permanent Maxillary Canines (Your Upper Pointy Corner Teeth)
Identification: These teeth are labeled as 6 and 11 in the Universal Numbering System.
Eruption Time: They generally erupt later than other front teeth, between 11 and 12 years of age.
Key Features:
They have a noticeable ridge on their front surface (labial ridge).
They have a single, sharp pointy tip (cusp).
These are the longest teeth in your upper jaw.
You can often see small ridges (imbrication lines) and grooves (perikymata) on the lower third of their front surface.
The side closest to the middle (mesial surface) touches the lateral incisor at the point where the biting edge area meets the middle third of the tooth.
The side farthest from the middle (distal surface) touches the first premolar in the middle third of the tooth.
Ways to Tell Them Apart:
The cusp slope towards the middle (mesial cusp slope) is shorter than the distal cusp slope.
The gum line curve (CEJ) on the mesial side is very pronounced.
Root Structure:
They have a single root with dips or curves on its side surfaces (proximal root concavities).
Inside, there is a single pulp canal with one pulp horn.
Permanent Mandibular Canines (Your Lower Pointy Corner Teeth)
Identification: These teeth are labeled as 22 and 27 in the Universal Numbering System.
Eruption Time: They typically erupt earlier than the upper canines, between 9 and 10 years of age.
Key Features:
They are narrower from front to back and from side to side compared to the upper canines.
Their back surface is generally smoother.
The bump near the gum line (cingulum) and the raised borders (marginal ridges) are not as developed as on the upper canines.
The roots of these teeth are the longest in the lower jaw.
The side closest to the middle (mesial surface) touches the lateral incisor in the biting edge area.
The side farthest from the middle (distal surface) touches the first premolar where the biting edge area meets the middle third of the tooth.
Ways to Tell Them Apart:
The cusp slope towards the middle (mesial cusp slope) is shorter.
The gum line curve (CEJ) on the mesial side is very noticeable.
Root Structure:
They have a single pulp chamber with one pulp horn.
Small ridges (imbrication lines) are usually faint or absent on these teeth.
Comparative Features of Maxillary and Mandibular Canines (Comparing Upper and Lower Canines)
Pictures or diagrams can help easily show the differences in how prominent the raised borders (marginal ridges) are between the upper and lower canines.