Types of Occlusions
I. Ideal Occlusion
● The static relationship between occlusal surfaces of the maxillary and
mandibular teeth or tooth analogues and functional occlusion
● A hypothetical concept - perfect occlusion
● Can only be achieved and seen in dentures, ideal casts, typodonts
● The basis or the goal of orthodontic treatment even if it cannot be achieved
II. Normal Occlusion
● There should be correct molar interarch relationship, mesiodistal crown
angulation, labiolingual crown inclination, no rotations, tight contacts, and
should have an occlusal plane
III. Centric Relation
● The relationship of the mandible to the maxilla where the condyle of the
mandible is located at its most superior and anterior position, resting on the
glenoid fossa against the articular eminence with the articular disc properly
interposed
IV. Centric Occlusion
● Relationship of the mandibular teeth with the maxillary teeth, ideally, at
maximum intercuspation
● If present, it is termed as the Habitual Occlusion or Position
● Not always the case, if the patient has malocclusion, or faulty restoration
V. Static Occlusion
● Concept of occlusion that is seen in the cast, therefore, movement is not
considered
VI. Dynamic Occlusion
● Concept of occlusion that considers the movement of the dentition, its shape
and position in relation to the skeleton and muscular structures
● One of the challenges in orthodontics is determining tooth positions if the
patient presents with a skeletal dysplasia
● In moderate to severe cases, it is impossible to achieve normal occlusion more
so, ideal occlusion
Six Keys to Normal Occlusion
1. Molar Relationship
● LEGASPI
,● The mesiobuccal cusp of maxillary permanent first molar occludes with the
mesiobuccal groove of the mandibular first permanent molar
● Likewise, the cusp tip of the maxillary cuspid occludes with the embrasure of
the mandibular cuspid and first permanent premolar
● the distal surface of the distal marginal ridge of the upper first permanent
molar occludes with the mesial surface of the mesial marginal ridge of the
lower second molar. The mesiobuccal cusp of the upper first permanent molar
falls within the groove between the mesial and middle cusps of the lower first
permanent molar
Occlusal Relationships of the Primary and Permanent Molars
A. Flush Terminal Plane Relationship
● Both the maxillary and mandibular planes are at the same level
anteroposteriorly
B. Mesial Step Relationship
● The maxillary terminal plane is relatively more posterior than the mandibular
terminal plane.
C. Distal Step Relationship
● The maxillary terminal plane is relatively more anterior than the mandibular
terminal plane
2. Crown Angulation
● Mesiodistal tip
● Also known as crown tipping
● It refers to the angle formed by the lines between the long axis of the clinical
crown and a 90° line tangent to the occlusal plane
● The gingival part of the crown is usually distal to the occlusal part.
● The gingival portion of the long axis of each tooth crown is distal to the
occlusal portion of that axis. The degree of tip varies with each tooth type
3. Crown Inclination
● Labiolingual/Buccolingual torque
● Also known as torque
● Measured by angle formed between a 90° line to the occlusal plane and line
tangent to the middle of the labial or buccal clinical crown
● for the upper Incisors the occlusal portion of the crowns labial surface ls labial
to the gingival portion. In all other crowns, the occlusal portion of the labial or
buccal surface is lingual to the gingival portion
● LEGASPI
, 4. No Rotations
● In normal occlusion, no rotations of teeth should be found in both arches
● If rotations are found in any arch, it indicates that there is an arch length
deficiency
● Besides, the arch form will be asymmetric and the caternary curve will be
distorted in a rotated arch
● there should be an absence of any tooth rotations within the dental arches
5. No Spacing
● This key explains that in ideal occlusion, the teeth should be within the normal
size and in harmony with the opposite arch
● All the teeth in both arches should have tight contacts in proximal contact
areas
● Dental arches with insufficient inclined anterior teeth and discrepancy in
tooth material will have localized spacing
● there should be an absence of any spacing within the dental arches
● LEGASPI
I. Ideal Occlusion
● The static relationship between occlusal surfaces of the maxillary and
mandibular teeth or tooth analogues and functional occlusion
● A hypothetical concept - perfect occlusion
● Can only be achieved and seen in dentures, ideal casts, typodonts
● The basis or the goal of orthodontic treatment even if it cannot be achieved
II. Normal Occlusion
● There should be correct molar interarch relationship, mesiodistal crown
angulation, labiolingual crown inclination, no rotations, tight contacts, and
should have an occlusal plane
III. Centric Relation
● The relationship of the mandible to the maxilla where the condyle of the
mandible is located at its most superior and anterior position, resting on the
glenoid fossa against the articular eminence with the articular disc properly
interposed
IV. Centric Occlusion
● Relationship of the mandibular teeth with the maxillary teeth, ideally, at
maximum intercuspation
● If present, it is termed as the Habitual Occlusion or Position
● Not always the case, if the patient has malocclusion, or faulty restoration
V. Static Occlusion
● Concept of occlusion that is seen in the cast, therefore, movement is not
considered
VI. Dynamic Occlusion
● Concept of occlusion that considers the movement of the dentition, its shape
and position in relation to the skeleton and muscular structures
● One of the challenges in orthodontics is determining tooth positions if the
patient presents with a skeletal dysplasia
● In moderate to severe cases, it is impossible to achieve normal occlusion more
so, ideal occlusion
Six Keys to Normal Occlusion
1. Molar Relationship
● LEGASPI
,● The mesiobuccal cusp of maxillary permanent first molar occludes with the
mesiobuccal groove of the mandibular first permanent molar
● Likewise, the cusp tip of the maxillary cuspid occludes with the embrasure of
the mandibular cuspid and first permanent premolar
● the distal surface of the distal marginal ridge of the upper first permanent
molar occludes with the mesial surface of the mesial marginal ridge of the
lower second molar. The mesiobuccal cusp of the upper first permanent molar
falls within the groove between the mesial and middle cusps of the lower first
permanent molar
Occlusal Relationships of the Primary and Permanent Molars
A. Flush Terminal Plane Relationship
● Both the maxillary and mandibular planes are at the same level
anteroposteriorly
B. Mesial Step Relationship
● The maxillary terminal plane is relatively more posterior than the mandibular
terminal plane.
C. Distal Step Relationship
● The maxillary terminal plane is relatively more anterior than the mandibular
terminal plane
2. Crown Angulation
● Mesiodistal tip
● Also known as crown tipping
● It refers to the angle formed by the lines between the long axis of the clinical
crown and a 90° line tangent to the occlusal plane
● The gingival part of the crown is usually distal to the occlusal part.
● The gingival portion of the long axis of each tooth crown is distal to the
occlusal portion of that axis. The degree of tip varies with each tooth type
3. Crown Inclination
● Labiolingual/Buccolingual torque
● Also known as torque
● Measured by angle formed between a 90° line to the occlusal plane and line
tangent to the middle of the labial or buccal clinical crown
● for the upper Incisors the occlusal portion of the crowns labial surface ls labial
to the gingival portion. In all other crowns, the occlusal portion of the labial or
buccal surface is lingual to the gingival portion
● LEGASPI
, 4. No Rotations
● In normal occlusion, no rotations of teeth should be found in both arches
● If rotations are found in any arch, it indicates that there is an arch length
deficiency
● Besides, the arch form will be asymmetric and the caternary curve will be
distorted in a rotated arch
● there should be an absence of any tooth rotations within the dental arches
5. No Spacing
● This key explains that in ideal occlusion, the teeth should be within the normal
size and in harmony with the opposite arch
● All the teeth in both arches should have tight contacts in proximal contact
areas
● Dental arches with insufficient inclined anterior teeth and discrepancy in
tooth material will have localized spacing
● there should be an absence of any spacing within the dental arches
● LEGASPI
