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80 Cards in this Set
- Front
- Back
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Clinical definition of eruption
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The cutting of newly formed tooth through the gums into the oral cavity
Only applies to primary teeth and non-succadaneous adult molars Succedaneous teeth don't cut through gingiva because the primary has already created a path |
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General definition of eruption
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The occlusal movement of a tooth from it's developmental position in the jaw to its functional position in occlusion
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Pre-eruptive movements
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movements of the tooth bud within its crypts prior to root formation and eruption
Involve repositioning the alveolus via resorption and deposition This allows the tooth buds to drift in several directions to compensate for crowding of the tooth buds and to compensate for the developing maxilla and mandible |
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Mesial drift
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Pre-eruptive movement that compensates for the significant amount of anterior growth in length of the jaws
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Distal drift
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Pre-eruptive movement that compensates for the somewhat less amount of posterior growth in length of the jaws
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Occlusal drift
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Pre-eruptive movement of the tooth buds to compensate for the growth in height of the jaws
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Buccal drift
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Pre-eruptive movement of the tooth buds to compensate for the growth in thickness of the jaws
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When does the pre-eruptive movement of the secondary succedaneous tooth bud occur?
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It occurs during the active eruption phase of its primary tooth
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Eruption of anterior single-rooted succedaneous teeth
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Secondary bud is initially positioned within the same crypt as actively erupting Primary tooth
As primary begins to form roots and erupt, the secondary bud migrates downward and labially Secondary settles underneath and slightly lingual to primary tooth Bone grows to partially separate the two into their own crypts The secondary dental lamina becomes the fibrous Gubernacular cord which resides in the Gubernacular canal. They function to guide eruption of the secondary tooth through the path of least resistance in bone |
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Gubernacular Cord & Canal
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Function to guide eruption of the secondary tooth through the path of least resistance in bone
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Where do secondary anterior tooth buds settle after pre-eruptive movements?
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Underneath and slightly lingual to the primary tooth
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Eruption of posterior multi-rooted succedaneous teeth
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Same as anterior but secondary tooth bud settles underneath and between the roots of the primary tooth
Because secondary crown is wider than the primary roots there is some initial resorption of the primary lingual root |
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Where do secondary posterior multi-rooted tooth buds settle after pre-eruptive movements?
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Underneath and between the roots of the primary tooth
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Eruption of non-succedaneous secondary molars
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Secondary molars come from lateral lamina not successional anlaga
Maxillary teeth start out with occlusal surfaces facing distally. Mandibular teeth start out with occlusal surfaces facing mesially. As maxilla and mandible grows, the molars rotate 90* into proper alignment |
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If maxillary 3rd molars get impacted?
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They are easy to remove because the maxilla bone is spongy with lots of blood vessels and heals quickly
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If mandibular 3rd molars get impacted?
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Removal is very difficult because the mandibular bone is so dense
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Active Eruption
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The occlusal migration of the tooth into occlusion beginning at the first onset of root formation
Must involve development of all the components of the periodontium (root, PDL, alveolar bone), all at the same time |
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What does active eruption begin?
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At the first onset of root formation
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Post-eruption Movements
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Movements of the functional tooth after it has already come into occlusal position
Compensates for growth of the jaw throughout life Maintains proper occlusion as the teeth experience occlusal and interproximal wear |
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Total bodily movements
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Pre-eruptive and post-eruptive movements
Occur by re-shaping the alveolus via resorption and deposition |
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Eccentric growth
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Movements of active eruption
Occur by changes in the tooth itself as one part of the tooth stays stationary 90% of the time the root remains stationary as the crown moves up into the oral cavity Remaining 10% of the time the crown remains stationary as the root tip moves down into alveolar bone |
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Nasmyth's Membrane
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Like a glue that attaches the REE to the enamel surface via hemidesmosomes as soon as the crown is down forming
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Phase I of active eruption
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1. Pressure of erupting tooth's cusp on soft tissue is what accounts for teething pain
2. dental follicle releases cytokines which causes Reduced Enamel Epi (REE) to secrete proteases/collagenases to digest the overlying soft tissue to relieve pressure 3. dental follicle releases Epidermal Growth Factor (EGF) to induce cellular proliferation of REE and oral epi 4. REE and oral epi meet with each other and basement membranes fuse to form Epithelial Cuff |
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What forms the Epithelial Cuff
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REE and Oral Epi
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Phase-2 of active eruption
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5. Cells in the center of Epithelial Cuff undergo apoptosis without bleeding or inflammation resulting in an epithelium lined Eruption Canal
6. As soon as tooth breaks through the oral epi there will be no pressure/pain and you get formation of the primary junctional epi, primary sulcular epi, primary enamel cuticle |
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What structures form as soon as the tooth breaks through the oral epi?
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Primary Junctional Epithelium
Primary Sulcular Epithelium Primary Enamel Cuticle |
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Primary Junctional Epi
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Formed through Phase 2 of Active Eruption
What the REE forms as soon as the tooth breaks through the oral epi Along with Primary Sulcular Epi |
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Primary Sulcular Epi
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Formed through Phase 2 of Active Eruption
What the REE forms as soon as the tooth breaks through the oral epi Along with Primary Junctional Epi |
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Primary Enamel Cuticle
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AKA Nasmyth's Membrane as soon as the tooth breaks through oral epi
Formed through Phase 2 of Active Eruption It is scraped off by chewing and replaced by Enamel Pellicle (Enamel Cuticle is NOT Enamel Pellicle) |
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Phase 3 of Active Eruption
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7. Tooth comes into full occlusal position
The oral epi proliferates downward to replace old REE forming the secondary junctional epi, secondary sulcular epi, and secondary enamel cuticle |
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Secondary Junctional Epi
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Forms during Phase 3 of Active Eruption
From oral epi replacing old REE |
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Secondary Sulcular Epi
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Forms during Phase 3 of Active Eruption
From oral epi replacing old REE |
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Secondary Enamel Cuticle
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Forms during Phase 3 of Active Eruption
From oral epi replacing old REE Consists of Dental Cuticle and Cemental Cuticle |
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Dental Cuticle
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What the glue is called when the JE migrates half on enamel and half on cementum
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Cemental Cuticle
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What the glue is called when the JE migrates down all the way to cementum
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What are the requirements for eruption?
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Dental follicle needed to have cementum, PDL, and alveolar bone forming at the same time
monocytes which convert to macrophages --> clast cells Clast cells to resorb bone, resorb roots, and widen bone crypts for eruption |
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Clast cells
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Required for eruption
Resorbs bone to make an Eruption canal for eruption of primary and secondary non-succedaneous teeth Resorbs roots of primary teeth for eruption of secondary succedaneous teeth Widens bone crypts for eruption of secondary succedaneous teeth |
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What are some eruption theories?
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Root growth theory
Bone growth theory Vascular pressure theory Ligament traction theory |
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Root Growth Theory of Eruption
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The down growth of the root causes pressure on the alveolus pushing the tooth upwards into occlusion
Problem: it takes 4-5g of pressure for tooth to erupt. With this pressure, the alveolar bone is more likely to resorb before any eruption |
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Bone Growth Theory of Eruption
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Selective deposition and resorption of the alveolar bone pushes the tooth upward into occlusion
Problem: There must be resorption at the top and deposition at the bottom of alveolar bone to get eruption. But the opposite is actually occurring (alveolar bone is getting resorbed at the bottom) Therefore, remodeling of bone occurs as a result of eruption, it is not the cause of for eruption |
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Remodeling bone
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Occurs as as result of eruption
Not a cause for eruption Alveolar bone gets resorbed at the bottom |
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Vascular Pressure Theory
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Increased vascular pressure causes edema pushing the tooth upwards into occlusion
Probably only a secondary factor in eruption |
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Ligament Traction Theory
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Remodeling of PDL collagen fibers PULLS the tooth upward into occlusion
The collagen fibers twist and shorten during their assembly into Oblique fibers putting torsion of the tooth pulling it upwards Support: If you interfere with collagen synthesis through Vit-C deficiency there is no eruption of teeth |
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When should eruption of Primary Dentition be complete?
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3 years
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When does eruption of 1st molars and Mandibular central incisors occur?
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6 years
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When should eruption of all 8 incisors be complete?
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8 years
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When does eruption of Mandibular canines and premolars occur?
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10-11 years
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When is the Inter-transitional Dentition phase?
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9-10 years.
Quiescent phase where not much is happening |
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When shoudl 2nd molars and maxillary canines erupt?
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12 years
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When should the eruption of Secondary Dentition be complete?
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13 years, except for 3rd molars
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What erupts during the early transitional dentition period?
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1st molars and Mandibular central incisors at 6 years
All 8 incisors at 8 years |
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What erupts during the late transitional dentition period?
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Mandibular canines and premolars at 10-11 years
2nd molars and maxillary canines at 12 years |
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What is secondary occlusion measured from
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1st molars
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Types of Secondary Occlusion
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Class I (normal)
Class II (retrognathic) Class III (Prognathic) |
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Class I Occlusion
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Normal
Maxillary Mesio-Buccal cusps fits within the Mandibular Buccal groove |
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Class II Occlusion
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Retrognathic
Maxillary Mesio-Buccal cusp is more MESIAL to the Mandibular Buccal groove Causes buck teeth |
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Class III Occlusion
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Prognathic
Maxillary Mesio-Buccal cusp is more DISTAL to the Mandibular Buccal groove Looks like under bite |
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How do you measure Primary Occlusion?
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From the 2nd molars
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Types of Primary Occlusion
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Mesial Step
Exaggerated Mesial Step Distal Step Flush Terminal Plane |
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Mesial Step
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Primary Occlusion
Maxillary molar is located DISTAL to Mandibular molar. Causes Class I adult occlusion 100% of the time |
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Exaggerated Mesial Step
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Primary Occlusion
Maxillary molar is located exaggerated DISTALLY to the Mandibular molar Causes Class III occlusion 100% of the time |
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Distal Step
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Primary Occlusion
Maxillary molar is located MESIAL to Mandibular Molar Causes Class II adult occlusion 100% of the time |
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Flush Terminal Plane
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Primary Occlusion
Becomes Class I occlusion 55% of the time if there is sufficient Mandibular leeway space Otherwise it becomes Class II Occlusion (45% of time) |
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Maxillary Primate Space
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Proper spacing in primary dentition
Located mesial to the canine, in between the lateral incisor |
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Mandibular Primary Spaace
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Proper spacing in primary dentition
Located distal to the canine in between the 1st premolar |
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Maxillary Leeway Space
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2 spaces
Created when secondary 2nd premolar erupts to replace primary 2nd molar Because premolar is smaller in width than primary molar, space is created Accommodates for crowding |
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Mandibular Leeway Space
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4 spaces
Created when secondary 2nd premolar erupts to replace primary 2nd molar Because premolar is smaller in width than primary molar, space is created Accommodates for crowding |
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What is the advantage of having a larger Mandibular Leeway Space than Maxillary?
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Allows for more mesial drift so that a Flush Terminal Plane occlusion can resolve itself
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What is the purpose to secondary dentition erupting more labially than primary?
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They erupt into a greater circumference of the jaw when done labially
Minimizes chance for crowding |
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Why are anterior teeth more susceptible to crowding than posterior teeth?
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Because Leeway spaces are located in the posterior part of the jaw
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Which teeth are more susceptible to crowding?
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Anterior dentition because of lack of Leeway spaces
Mandibular dentition because the Maxillary can limit how far foward Mandibular teeth can erupt |
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Why is the Mandibular arch more susceptible to crowding that Maxillary arch?
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Because the maxillary arch limits how far forward the mandibular teeth can erupt into a larger circumference of the jaw
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Incisor Liability
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Variation of normal
1-2mm of Mandibular anterior crowding |
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Which teeth are most common to be congenitally missing?
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Maxillary laterals
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Which teeth are most common to be supernumerary teeth?
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Maxillary mesiodens in between Maxillary centrals
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What causes Maxillary central diastemma
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Due to excessive pull of very short labial frenulum
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Dentoalveolar Protrusion
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Teeth and supporting alveolar bone flare forward and protrude
Due to thumb-sucking and tongue thrusting Leads to Open Anterior Bite |
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What are some normal variations to eruption patterns?
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Flush Terminal Plane
Incisor Liability Ugly Duckling Stage |
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Ugly Duckling Stage
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Normal Eruption Pattern
Wide spaces between slightly protruded Maxillary anterior teeth Resolves itself when Maxillary Canines erupt at age 12 |
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Maxillary Canine Eruption
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Occurs at age 12
Most troublesome teeth to the occlusion b/c they erupt last when there's no more room Eruption is guided by Maxillary lateral roots Maxillary canine overlapping a maxillary lateral root means potential for crowding |
