Anatomy - Obj 6.1 - 6. (Week 3 PP) Flashcards
Anterior Permanent Dentition
- There are 12 anterior teeth in the permanent
dentition, six in each dental arch - The permanent anterior teeth include the central
incisors, lateral incisors, and canines - The central incisors are closest to the midline, the
lateral incisors are the second teeth from the
midline, and the canines are the third teeth from
the midline - All anterior teeth are succedaneous, replacing
primary teeth of the same type
Characteristics of Permanent Anterior Teeth
- All anterior teeth have a cingulum, a rounded,
raised area on the cervical third of the lingual
surface - The lingual surface on anterior teeth has rounded,
raised borders on the mesial and distal surfaces
called marginal ridges - Some anterior teeth have a fossa, which is a wide,
shallow depression on the lingual surfaces (Bird &
Robinson, 2021)
Permanent Incisors
- There are eight permanent incisors
◦ Four maxillary
◦ Four mandibular - The maxillary group comprises two central incisors
and two lateral incisors, as does the mandibular
group - These teeth complement each other in form and
function - The central incisors erupt about a year or so
before the lateral incisors do
Maxillary Central Incisors
Maxillary central incisors (1.1 and 2.1) have unique
anatomical features
* Larger in all dimensions, especially mesiodistally, than
a permanent mandibular central incisor
* Root is short compared with the roots of other
permanent maxillary teeth
* All lingual surface features, including the marginal
ridges, lingual fossa, and cingulum, are more
prominent on the maxillary central incisor than on the
mandibular central incisor
The incisal edge is also known as the incisal surface or incisal plane
* When newly erupted, the central and lateral
incisors have three mamelons, or rounded enamel
extensions on the incisal ridge, or edge
* The mamelons usually undergo attrition shortly
after eruption
Maxillary Lateral Incisors
The maxillary lateral incisors (1.2 and 2.2) are
smaller than the central incisors in all dimensions except root length
* They usually erupt after the maxillary central
incisors
* The crown of a maxillary lateral incisor has a single
root that is relatively smooth and straight but may
curve slightly distally
* Recognizing this feature is helpful in the mounting
of radiographs
The lateral incisors vary in form more than any
other tooth in the mouth, except the third molars,
and are often congenitally missing
* Because of the variations in form, the permanent
maxillary lateral incisors present challenges during
preventive, restorative, and orthodontic procedures
* Open contacts (spaces between teeth), called
diastema, often occur in this area because of the
variations in tooth size and position in the arch
Pegged Maxillary Lateral Incisor
“stump tooth”
Mandibular Incisors
- The permanent mandibular incisors are the
smallest teeth of the permanent dentition and the
most symmetric - The central and lateral incisors of the mandibular
arch resemble each other - Generally, the lateral incisor is larger than the
central incisor, in contrast to the teeth in the maxillary arch - Supragingival tooth deposits, such as plaque, calculus, and stain, tend to collect in the lingual concavity of the mandibular incisors
Mandibular Central Incisors
The mandibular central incisors (3.1 and 4.1) are
the smallest and simplest teeth and are bilaterally
symmetric
* Each has a small centered cingulum, subtle lingual
fossa, and equally subtle marginal ridges
* The crown of a mandibular central incisor is
narrower on the lingual surface than on the labial
surface
* Developmental horizontal lines on anterior teeth,
or imbrication lines, and developmental
depressions usually not present or very faint
Mandibular Lateral Incisors
The mandibular lateral incisors (3.2 and 4.2) are
slightly larger than the mandibular central incisors
but otherwise similar to them
* The lateral teeth usually erupt after the mandibular central incisors
* The lateral incisors have a small, distally placed
cingulum
* Greater height of the cementoenamel junction
(CEJ) curvature on the mesial surface than on the
distal surface helps distinguish the right
mandibular lateral incisor from the left incisor
Permanent Canines
- The permanent canines are the four anterior teeth
located at the corner of each quadrant for each
dental arch
The permanent canines are the longest teeth in
the dentition - The root is usually the length of the crown
- This large root is externally manifested by the
bony vertical ridge called the canine eminence
(Bird & Robinson, 2021)
Maxillary Canines
The maxillary canines (1.3 and 2.3) usually erupt
after the mandibular canines, after the maxillary
incisors, and possibly after the maxillary premolars
* The cusp tip is sharper on a maxillary canine
* The mesial cusp slope is usually shorter than the
distal cusp slope in both the maxillary and the
mandibular canines when they first erupt
* The length of these cusp slopes, and the cusp tip
can change with attrition
Mandibular Canines
The mandibular canines (3.3 and 4.3) usually erupt
before the maxillary canines and after most of the
incisors have erupted
* A mandibular canine closely resembles a maxillary
canine
* Although the entire tooth is usually as long, a
mandibular canine is narrower labiolingually and
mesiodistally than a maxillary canine
* The lingual surface of the crown of the mandibular
canines is smoother than that of the maxillary canines
and has a less developed cingulum and two marginal
ridges
Clinical Considerations with Canine s
The maxillary canines may erupt labially or
lingually in relation to the surrounding teeth
* The maxillary canines may also fail to erupt fully
and may remain impacted
* This occurs because the permanent maxillary
canines erupt after the maxillary incisors and
possibly after the premolars and their arch spaces
have closed
Posterior Permanent Dentition
The permanent posterior teeth include the
premolars and molars
* The crown of each posterior tooth has an occlusal
surface, bordered distally and mesially by marginal
ridges
* The occlusal surfaces have two or more cusps
* Imagine each cusp as a mountain with sloping
areas, or cusp ridges, extending from the top of
the mountain; between the ridges are sloping
areas called inclined cuspal planes
Each shallow, wide depression on the occlusal
table is a fossa
* One type of fossa on posterior teeth, the central
fossa, is located where the cusp ridges converge in
a central point, where the grooves meet
* Another type of fossa is the triangular fossa
* Sometimes located in the deepest portions of the
fossa are occlusal developmental pits
◦ Each pit is a sharp pinpoint depression where two or
more grooves meet
Permanent PreMolars
- There are eight premolars in the permanent
dentition, two in each quadrant - They are located posterior to the canines and
immediately anterior to the molars - There are two types of premolars
◦ First
◦ Second
Maxillary First Premolars
A maxillary first premolar (1.4 and 2.4) is larger
than a maxillary second premolar
* Each maxillary first premolar has two cusps
(buccal and lingual) and two roots (facial and
lingual)
* Both maxillary premolars erupt earlier than the
mandibular premolars
The maxillary first premolar has a bifurcated root
(two roots: one buccal and one lingual)
* Some first premolars have roots that are joined, or
fused
* The roots are shorter in length and resemble the
roots of the molars
Maxillary Second Pre-Molars
- Each maxillary second premolar (1.5 and 2.5) has
two cusps (buccal and lingual) and one root
Differences between Second and First Maxillary Premolars
- The cusps are closer in length on the second premolar
- The lingual cusp is slightly shorter, but not as short as
the cusp on the maxillary first premolar - The mesiobuccal cusp slope is shorter than the
distobuccal cusp slope on the second premolar - The cusps of the secondary premolar are not as sharp as
those of the maxillary first premolar - The second premolar has only one root and one root
canal - The second premolar is wider buccolingually than
mesiodistally
Mandibular First Premolars
Each mandibular first premolar (3.4 and 4.4) has a
long and well-formed buccal cusp and a small,
nonfunctioning lingual cusp
* The lingual cusp may be no larger than the
cingulum on some maxillary canines
* The mandibular first premolars are smaller and
shorter than the mandibular second premolars
Mandibular Second Premolars
- The permanent mandibular second premolars (3.5
and 4.5) erupt distal to the mandibular first
premolars - They are the succedaneous replacements for the
primary mandibular second molars - There are two forms of the mandibular second
premolar
◦ Three-cusp type, or tricuspidate form
◦ Two-cusp type, or bicuspidate form (Bird & Robinson,
2021)
Mandibular Second Premolar Groove Types
“U” Type
“H” Type
“Y” Type
Clinical Considerations with PreMolars
The maxillary and mandibular premolars work
with the molars in the chewing of food
* The first premolars help the canines in shearing or
cutting bits of food
* The premolars also support the corners of the
mouth and cheeks
Permanent Molars
There are 12 molars, three in each quadrant, in
the permanent dentition
* The molar crowns have four or five short, blunt
cusps, and each molar has two or three roots that
help support the larger crown
There are three types of molars: First, second, and
third
* The first and second molars are also called the 6-
year and 12-year molars because of the
approximate ages at which they erupt
Maxillary Molars
- Usually, the first permanent teeth to erupt into
the maxillary arch - Each maxillary molar usually has four major cusps,
with two on the buccal portion of the occlusal
table and two on the lingual - Each maxillary molar has three well-separated and
well-developed roots - A tooth with three roots is said to be trifurcated,
which means “divided into thirds”
Maxillary First Molars
The maxillary first molars (1.6 and 2.6) are the first
permanent teeth to erupt into the maxillary arch
* They erupt distal to the primary maxillary second
molars and are therefore nonsuccedaneous (do not
replace the primary teeth)
* The maxillary first molar is the largest tooth in the
maxillary arch and also has the largest crown in the
permanent dentition
* This molar is composed of five developmental lobes,
two buccal and three lingual
* The fifth cusp is called the cusp of Carabelli
Maxillary Second Molars
- The crown of the maxillary second molar (1.7 and
2.7) is somewhat shorter than that of the first
molar, and it usually has four cusps - No fifth cusp is present
- There are three roots
- The roots of the secondary molars are smaller
than those of the first molars
◦ The lingual root is still the largest and longest
Maxillary Third Molars
The maxillary third molars (1.8 and 2.8) differ
considerably in size and contour
* The crown of the maxillary third molar is smaller
and the roots are usually shorter
* The roots of the maxillary third molar tend to fuse,
and the result is a single tapered root
* People sometimes refer to the maxillary third
molars as the “wisdom” teeth because they erupt
last
Clinical Considerations with Maxillary Molars
The roots of the maxillary molars may penetrate
the maxillary sinus as a result of accidental trauma
or during an extraction
* The permanent maxillary third molars may fail to
erupt and may remain impacted within the
alveolar bone
* If the maxillary first molar is lost, the second molar
can tip and drift into the open space, causing
difficulty in chewing and furthering periodontal
disease
Mandibular Molars
- The mandibular molars erupt 6 months to 1 year
before the corresponding permanent maxillary
molars - The crowns of the mandibular molars have four or
five major cusps, with two lingual cusps always of
about the same width - All mandibular molars are wider mesiodistally
than buccolingually, similar to anterior teeth
Each mandibular molar has two well-developed roots, one mesial and one distal - A tooth with two roots is referred to as bifurcated,
which means “divided into two” - A bifurcation is the area at which the two roots
divide
Mandibular First Molars
The permanent mandibular first molars (3.6 and
4.6) erupt between 6 and 7 years of age
* These teeth are commonly the first permanent
teeth to erupt in the oral cavity
* The two roots, mesial and distal, of a mandibular
first molar are larger and more divergent than
those of a second molar (Bird & Robinson, 2021)
* 5 cusps: MB, DB, D, ML and DL
* Two facial (buccal) developmental grooves which
may end in pits.
Mandibular Second Molars
The mandibular second molars (3.7 and 4.7) erupt
between 11 and 12 years of age
* These teeth erupt distal to the permanent first
molars and therefore are nonsuccedaneous
* The crown of the mandibular second molar is
slightly smaller than that of the first molar in all
directions
* The crown has four well-developed cusps
Mandibular Third Molars
- The mandibular third molars (3.8 and 4.8) are
similar to the maxillary third molars in that they
vary greatly in shape - There is no typical mandibular third molar
- This molar is usually smaller in all dimensions than
the second molar - The third molar consists of four developmental
lobes - A mandibular third molar has two roots that are
fused, irregularly curved, and shorter than those
of a mandibular second molar
Clinical Considerations with Mandibular Molars
The lingual inclination of the crowns of the
mandibular molars can make it difficult to position
the oral evacuator
* The lingual inclination of the molar teeth can also
pose problems in oral hygiene for patients, who
may miss the lingual gingiva with the toothbrush
Permanent Eruption Dates
*6-7 Years
Mandibular Central Incisors
Maxillary 1st Molars
Mandibular 1st molars
*7-8 years
Maxillary Central Incisors
Mandibular Lateral Incisors
*8-9 years
Maxillary Lateral Incisors
*9-10 years
Mandibular Cuspids
*10-11 years
Max 1st Premolar
Mandi 1st premolar
*10-12 years
Max 2nd premolar
*11-12 years
Max Cuspids
*11-13 years
mandi 2nd molar
Max 2nd molars
*12-13 years
Mandi 2nd premolars
*17-21 years (if at all)
mandi 3rd molar
Max 3rd molars
Occlusion
Relationship between maxillary and mandibular
teeth when upper and lower jaws are fully closed
and relationship between teeth in the same arch
Malocclusion
Abnormal or malposition relationships of maxillary teeth to mandibular teeth when they are in centric occlusion
is related to lack of an overall ideal form in the dentition while in CO
Centric Occlusion
- Centric occlusion (CO) is the voluntary
position of the dentition that allows the maximum contact when the teeth occlude
Each tooth of one arch is in occlusion with two others in the
opposing arch, except for the mandibular central incisors and maxillary third molars
Centric Relation
Is the end point of closure of the mandible; the mandible is in the most retruded position to which it can be carried by the musculature and ligaments.
* Ideally, when the mandible is in CR, the dentition should be in CO (thus centric relation equals centric occlusion, or CR = CO)
* Independent of tooth contact
Curve of Spee
When the maxillary and mandibular teeth come into CO, they align along anteroposterior and lateral curves.
* This is produced by the curved alignment of all the teeth and is especially evident when viewing the posterior teeth from the buccal view
Overjet
- When the teeth usually occlude in CO, the
maxillary arch horizontally overlaps the mandibular arch, which is referred to as overjet. - Overjet is measured in millimeters with the tip of a periodontal probe, once a patient is in CO.
- The probe is placed at 90°or at a right angle to the labial surface of a mandibular incisor at the base of the incisal
ridge of a maxillary incisor
Overbite
- In CO, the maxillary arch also vertically overlaps the mandibular arch, which is referred to as overbite.
The amount of vertical overlap, usually
2 to 5 mm between the anterior sextants of the
two arches, allows contact between the posterior teeth during mastication. - It is usually expressed as a percentage at around 20% to 30%
Severe overbite
When the maxillary arch and its incisors have a more pronounced overlap with the mandibular arch and its incisors, it causes a severe overbite (or deep overbite).
Underbite
When the mandibular arch and its incisors extends beyond the maxillary arch and its incisors, it is causes an underbite
Crossbite
Occurs when a mandibular tooth or teeth are placed
facially to the maxillary teeth
Openbite
- Teeth do not occlude.
End-to-End bite
Teeth occlude without the maxillary teeth
overlapping the mandibular teeth.
Malocclusion Classification
- The Angle classification of malocclusion does not describe normal or even ideal occlusion, only malocclusion of the molars and canines.
- The basis of the Angle classification system was the simple hypothesis that the permanent maxillary first molar was the key to occlusion.
- Later, the relationship of the opposite arch canines was also evaluated
- In the Angle classification, most cases of malocclusion are grouped into three main classes, according to the position of the permanent maxillary first molar to the mandibular first molar.
- This classification system is based on the relationship of the teeth and not the skeletal considerations that are due to the disproportionate size or position of the jaws
Three main classes are designated by Roman numerals (I to III), and they assume that both sides of the dentition are affected equally, unless specifically noted. - Separate defining classifications can be made, depending on which side is affected
Malocclusion: Gnathic Index
Each type of facial profile present (either mesognathic,
retrognathic, or prognathic) can be measured by the
gnathic index
* This measurement gives the degree of prominence of the
maxillae as opposed to the mandible
Gnathic Index: Mesognathic
Perpendicular - jaw is in the middle
Gnathic Index: Retrognathic
Jaw is inward
Gnathic Index: Prognathic
Jaw is outward
Class I Malocclusion - Neutrocclusion (Angle Classification)
- All cases in a Class I malocclusion
(neutroclusion) within a permanent dentition are characterized by an ideal MD relationship of the jaws and dental arches. - the MB cusp of the maxillary first molar occludes with the MB groove of the mandibular first molar
- Class I malocclusion is due to dental malalignments, such as crowding (patients refer to these as “crooked
teeth”) or irregular spacing within the jaws
Molar: Mesiobuccal cusp of maxillary 1st molar occluding with MB groove of mandibular 1st molar
Canines: Maxillary occluding with distal half of mandibular canine and mesial half of mandibular first premolar
Dental malalignment present - such as crowding or irregular spacing; mesognathic profile
Class II Malocclusion - Distocclusion (Angle Classification)
All cases in Class II malocclusion (distoclusion) within the
permanent dentition are characterized by the MB cusp of the maxillary first molar occluding (by more than the width of a premolar) mesial to theMB groove of the mandibular first molar
The major group of Class II malocclusion has
two subgroups, division I and division II,
based on the position of the anterior teeth,
shape of the palate, and resulting facial profile
Molar: MB cusp of maxillary first molar occluding (by more than width of premolar) mesial to MB groove of mandibular first molar
Canines: Distal surface of mandibular canine distal to mesial surface of maxillary canine
Division 1: Maxillary incisor protruding facially from mandibular incisors with severe overbite; retrognathic profile
Division 2: Maxillary central incisors either upright or retruded and maxillary lateral incisors either tipped labially or overlapping central incisors with sever overbite; mesognathic profile
Class III Malocclusion - Mesiocclusion (Angle Classification)
In all cases of a Class III malocclusion (mesioclusion) within a permanent dentition, are characterized by the MB cusp of the maxillary first molar occludes (by more than the width of a premolar) distal to the MB groove of the mandibular first molar
Molar: MB cusp of maxillary first occluding (by more than width of premolar) distal to MB groove of mandibular first molar
Canines: Distal surface of mandibular mesial to mesial surface of maxillary (by at least width of premolar)
Mandibular incisors protruding facially from maxillary incisors with underbite and are in complete cross bite; prognathic profile
Primary Occlusion
The ideal molar relationship in the primary dentition,
when in CO, is referred to as the terminal plane
Flush Terminal Plane
flush terminal plane - in which the primary maxillary and mandibular second molars are in an end-to-end relationship
Mesial Step
a mesial step, in which the primary mandibular second molar is mesial to the maxillary second molar
With the presence of a mesial step, an ideal permanent molar relationship usually occurs after the eruption
of the permanent dentition.
* In about 80% of those individuals with mesial step less than 2 mm, Angle Class I molarrelationship will result
Distal Step
A distal step relationship, in which
the primary mandibular second molar is distal to the
maxillary second molar, is not an ideal molar relationship in
the primary dentition and thus is not a type of terminal plane relationship
Lobes/Tooth buds
Lobes can also be referred to as tooth buds. They give rise to the tooth structures providing their distinctive anatomy such as depressions, grooves, and fissures in the areas of fusion. An anterior tooth comes from 4 lobes identified by the 2 demarcation lines outlining 3 distinct sections being mamelons, the forth lobe forms the cingulum
Which premolar usually has two roots?
1st maxillary premolar usually has 2 roots (the rest have one root only) also has 2 canals - even if root is not bi
Which teeth are non-succedaneous?
The molars
Occlusion
Occlusion is the term used to describe the relationship of the upper and lower teeth when the teeth are closed together or during excursive movements when the teeth are touching.
A tooth that contacts another tooth in the opposite arch during occlusion is referred to as….
the “antagonist”
Recognition of the patient’s occlusion and understanding the oral health problems of malocclusion can help in accomplishing the following:
-Provide information for the diagnostic work-up and for planning dental hygiene care.
-Plan personalized instruction in relation to such factors as oral habits, masticatory efficiency, personal oral care procedures, and predisposing factors to dental and periodontal disease.
-Adapt techniques of instrumentation to mal-positioned teeth or groups of teeth.
-Plan the frequency of recall appointments for professional care on the basis of deposit retention areas, particularly those which are difficult to reach in routine care.
-Assist by recording the general features of malocclusion for special consideration by the dentist who may wish to refer the patient to a specialist.
Malocclusion
Any deviation from the ideal positioning of the teeth whether it is a minor deviation of one tooth or a severe variation involving several teeth, or the jaws, creates a malocclusion.
The best known system for classifying malocclusion
The best-known system for classifying malocclusions was described by Dr. Edward Angle in 1898. This system is based on the mesiodistal relationship of the upper and lower first molars and cuspids to each other.
Which tooth is considered the “key” to occlusion?
The maxillary first molar is considered the “key” to occlusion
Ideal Occlusion
This term implies a complete, harmonious relationship between the teeth and all other structures involved in the masticatory system. The teeth conform to a specific pattern which includes 138 occlusal contacts in the closure of the permanent teeth. This relationship rarely exists.
Normal Occlusion
Since ideal occlusion seldom occurs, normal occlusion conforms closely to an ideal occlusal relationship but considers some variations from it. Variations are considered optimum if there is functional comfort and stability of alignment.
In proper occlusion, each tooth has an appropriate opposing contact. A malpositioned tooth can cause the improper distribution of stress resulting in a breakdown of the periodontium and/or TMJ pathology.
The position of the first molars is the same as in an ideal occlusion
What is the amount of force exerted during mastication?
Each tooth must be able to withstand the forces exerted during mastication - 28,000 pounds per square inch
Centric Occlusion
The relationship of the occlusal surfaces of one arch to those in the opposing arch at a physical rest position. The posterior teeth are closed. The anterior teeth have very light or no contact. Centric occlusion is not determined by muscle or bone, it is the habitual way the teeth come together
Centric Relation
Centric relation refers to the position of the mandible relative to the maxilla that is determined by the maximum contraction of the muscles of the jaw (the most retruded position of the condyle in the mandibular fossa). This relationship occurs during strong muscle contractions such as swallowing. It is a relationship of bone to bone brought about by allowing the muscles to contract in their most natural posture to their most comfortable and effective position
Curve of Spee
The occlusal plane of the tooth is a line that extends from the incisal edge of the central incisors to the distal-buccal cusp of the second molar. This line forms a curve when the teeth have erupted and are in normal alignment
Functional Malocclusion
Functional malocclusion is described as an occlusal deviation created by habits or muscular dysfunctions. Certain habits (eg. thumb sucking) may cause malocclusion depending on the intensity, duration, and/or the age at which they occur
Muscular Forces
After the teeth erupt, the tongue pushes them into a position farther facially towards the lips and cheek
Resistance from the muscles that form the cheeks and lips control these forces and prevent the teeth from moving too far facially (Bird & Robinson, 2021).
The balance between these two forces allows the teeth to be brought into proper alignment. If this balance of forces is disturbed, abnormal alignment of the teeth can result
abnormal Tongue Thrust
An abnormal forward thrust of the tongue against the anterior teeth causing maxillary anterior teeth to protrude.
Lateral excursion
In lateral excursion, the mandible moves toward the right or left side. The side to which the mandible moves is called the working side. The side away from which the mandible is moving is referred to as the non-working side (On artificial teeth, this non-working side is referred to as the balancing side)
a working side contact exists when…
A working-side contact exists when the mandible is moved to one side, with the buccal cusps of maxillary and mandibular teeth touching each other and the lingual cusps directly over each other
Lateral mandibular glide / Canine Rise
In lateral mandibular glide, only a few pairs of interlocking cusps make contact. The cuspids carry the bulk of the contact - this is called canine rise because the lower cuspid opens the bite by gliding down the lingual surface of the maxillary cuspid
Pre-Mature contact
When the jaw closes, all of the teeth should come into contact at the same time. If one tooth touches before the others, this tooth is called a pre-mature contact
posterior crossbite
Maxillary or mandibular posterior teeth are either buccal or lingual to their normal position. This may occur bilaterally or unilaterally
anterior crossbite
Maxillary incisors are lingual to the mandibular incisors
when one or more upper incisors bites behind the lower incisors (front teeth)
Edge to Edge bite
Incisal surfaces of maxillary teeth occlude with incisal surfaces of mandibular teeth instead of overlapping
end to end bite
Molars and bicuspids occlude cusp-to-cusp as viewed from the buccal
open bite
Lack of occlusal or incisal contact between maxillary and mandibular teeth because either or both have failed to reach the line of occlusion. The teeth cannot be brought together and space remains due to the arching of the line of occlusion
overjet
The horizontal distance between the labio-incisal surfaces of the mandibular incisors and the linguo-incisal surfaces of the maxillary incisors
underbite
The maxillary teeth are lingual to mandibular teeth. The horizontal distance between the labio-incisal surfaces of the maxillary incisors and the linguo-incisal surfaces of the mandibular incisors
Overbite
Overbite is the vertical distance by which the maxillary incisors overlap the mandibular incisors - ranging from normal, moderate to severe
Labioversion or buccoversion
A tooth positioned more facially than normal
Infraversion
A tooth positioned below the plane of occlusion
Supraversion
A tooth positioned above the plane of occlusion, also known as over-eruption.
Torsiversion
A tooth that is rotated, either mesially or distally.
Effects of a Loss of a Tooth
When a tooth is missing, the adjacent teeth tend to drift and tip into the open space, and the opposing tooth over-erupts into the space.
Normal (Ideal) Occlusion
The mesiobuccal cusp of the upper first permanent molar occludes with the buccal groove of the lower first permanent molar
Class I - Neutroclusion (Angie)
The molar relationship is normal but individual teeth or groups of teeth are out of position
Class II - Distoclusion (Angie)
The buccal groove of the lower first permanent molar is distal to the mesiobuccal cusp of the upper first permanent molar
Division I – mandible is retruded and all upper incisors protrude
Division II – mandible is retruded and one or more upper incisors are retruded
Class III - Mesioclusion (Angie)
The buccal groove of the lower first permanent molar is mesial to the mesiobuccal cusp of the upper first permanent molar
Class I facial profile
Mesiognathic profile
Class II division 1 facial profile
Retrognathic profile
Class III Facial profile
Prognathic profile
Class II division 2 facial profile
mesiognathic profile, often with a prominent mandible
