Craniofacial Growth, Developing Dentition and Occlusion Flashcards
1
Q
Period of the ovum
A
- Day 0 to 10-14
- Fertilization to implantation
- Cell division (proliferation)
2
Q
Period of the embryo
A
- Week 2 to 8
- Remainder of 1st trimester
- Cell differentiation
3
Q
Period of the fetus
A
- Week 8 to 40
- 2nd and 3rd trimester
- Maturation of organ systems
4
Q
Branchial arch structure
A
Cartilage, a nerve, and blood vessels surrounded by mesenchyme
5
Q
Palate formation
A
- Initially palatal shelves grow vertically on either side of the developing tongue
- Palatal shelf elevation occurs rapidly bringing the shelves into proximity
- Fusion of the shelves to each other and to the nasal septum follows
6
Q
Definition of growth
A
- an increase in size or number
- anatomical phenomenon
7
Q
Definition of development
A
- an increasing degree of organization, complexity, and specialization
- physiological and behavioral phenomenon
8
Q
Hypertrophy
A
Increase in size
9
Q
Hyperplasia
A
Increase in number
10
Q
Interstitial growth
A
- Occurs throughout the tissue
- Soft tissues
- Uncalcified cartilage
11
Q
Appositional growth
A
- Occurs only on the surface of the tissue
- Hard tissues
- Calcified tissues
12
Q
Growth of cartilage
A
- Grows by appositional and interstitial growth
- Appositional growth: new cartilage is added to the surface of the cartilage by chondroblasts from the inner layer of the perichondrium
- Interstitial growth: new cartilage is formed within the cartilage by chondrocytes that divide and produce additional matrix
13
Q
Intramembranous
A
- No structural precursor
- Secretion of bone matrix directly within connective tissues
- Cranial vault, maxilla, mandible
14
Q
Appositional
A
- Cartilaginous precursor
- Replacement of cartilage with centers of ossification
- Axial and appendicular skeleton, cranial base
AKA endochondral ossification? Needing a cartilage precursor
15
Q
Condylar cartilage
A
- Arises independently as secondary cartilage
- Initially separated from the body of the mandible, but eventually fuses in fetal life
- Both endochondral and intramembranous ossification contribute to the origin of the mandible **
16
Q
Craniofacial complex
A
1) Cranial vault
2) Cranial base
3) Nasomaxillary
4) Mandible
17
Q
Differential growth patterns
A
- Neural is the majority at first, then plateaus
- Lymphoid tissue increases then decreases
- Mandible follows the general curve
18
Q
Cranial vault
A
- Intramembranous, no interstitial growth
- Anterior fontanelle, mastoid fontanelle, sphenoid fontanelle, posterior fontanelle
19
Q
Cranial base
A
- Endochondral growh
- Frontal bone, sphenoid bone, temporal bone, occipital bone
20
Q
Maxilla
A
- Intramembranous
- Sutures connects the maxilla to the rest of the cranium
- Apposition occurs upward and backward, however, it results in downward and forward net effect.
21
Q
Maxillary growth
A
- Apposition of the bone at the sutures –> displaces maxilla downward and forward
- Apposition of bone at the maxillary tuberosity –> increases arch depth
- Resorption at anterior surface of maxilla –> maintains position of anterior surface
22
Q
Mandible
A
Mix of both intramembranous and endochondral
23
Q
Mandibular growth
A
- Endochondral growth at the condyle –> displaces mandible downward and forward
- Apposition at posterior border, resorption at anterior border of ramus –> relocates ramus posteriorly, displaces mandible downward and forward
24
Q
Primary germ layers
A
- Ectoderm –> Epidermis (skin), oral mucosa, enamel
- Mesoderm –> Skeletal muscle
- Endoderm –> Lining of the gut (pharynx)
- Neural crest –> Connective tissue proper, cartilage, bone, dentin, cementum, pulp, PDL
25
___ is from the ectoderm, while the rest of the dental tissues comes from the ____
Enamel; neural crest
26
Stages of tooth development
```
A) Bud
B) Cap
C) Bell
D) Dentinogenesis
E) Amelogenesis
F) Crown formation
G) Root formation and eruption
H) Root completion
```
27
Root formation timeline
Root formation begins BEFORE eruption, but finishes 2-3 years AFTER
28
Life cycle of the tooth
1) Growth
- Initiation
- Proliferation
- Histodifferentiation
- Morphodifferentiation
- Apposition
2) Calcification
3) Eruption
4) Attrition
29
Stage of tooth development: Initiation
Initial formation of the bud
30
Stage of tooth development: Proliferation
Proliferation of the cells of the bud to proceed through the cap stage
31
Stage of tooth development: Histodifferentiation
Differentiation of the cells of the tooth germ into inner and outer epithelium and dental papilla (bell)
32
Stage of tooth development: Morphodifferentiation
Tooth germ begins to take on the morphology of the tooth (advanced bell)
33
Stage of tooth development: Apposition
Tissue matrix is deposited
34
Tooth germ composition
- Enamel organ --> from the ectoderm, surrounded by ectomesenchyme forming the dental sac and papilla
- Dental papilla
- Dental sac
35
Dental papilla becomes?
Dentin and pulp
36
Dental sac becomes?
PDL and cementum
37
Enamel organ
- Differentiates into 4 layers: outer enamel epithelium (OEE), inner enamel epithelium (IEE), stellate reticulum, stratum intermedium
- IEE becomes ameloblasts that produce enamel
- Stellate reticulum and stratum intermedium are the supporting structures for the IEE
38
Histodifferentiation and apposition
- Odontoblasts are signaled by preameloblasts to make predentin -- beginning the first dentin at the DEJ
- Preameloblasts differentiate into mature ameloblasts when stimulated by dentin laid down by odontoblasts
39
Basement membrane or basal lamina
- Microscopic interface between epithelial and mesenchymal tissues
- Product of both tissues
- Mediator of molecular signaling that controls differentiation
- Becomes the dentino-enamel junction
40
Root formation
- Begins towards the end of crown formation, and will not complete until 2-3 years after tooth eruption
- Outer enamel epithelium + inner enamel epithelium = Hertwig's epithelial root sheath --> function is to GUIDE the SHAPE and NUMBER of roots
41
Cementogenesis
- Breakup of hertwig's epithelial root sheath allows cells of dental sac to contact root dentin and differentiate into cementoblasts.
- These cells produce cemented which mineralizes to form cementum.
- The root sheath thus directs the cementoblasts where to go.
42
PDL and tooth eruption
- Root formation is not complete until 2-3 years after eruption
- Cementum of the root is connected to the alveolar bone via connective fibers called the Periodontal Ligament (PDL)
- As the tooth erupts --> more and more PDL will form
43
Three phases of tooth eruption
1) Preeruptive --> root formation begins and tooth is moving toward bony surface
2) Eruptive (prefunctional) --> development of tooth root through gingival emergence; most roots are 1/2 to 2/3 developed upon gingival emergence
3) Eruptive (functional) --> From gingival emergence to the point where the tooth meets its antagonist
44
Developmental events of dentition
- Primary dentition stage (6 months to 6 years) --> first inter-transitional period
- Mixed dentition stage (6 to 12 years)
- First transitional period
- Second inter-transitional period --> ugly ducking stage
- Second transitional period
- Permanent dentition stage (12 years to adult)
45
Eruption of primary teeth
Maxillary:
Central (10 mo) --> Lateral (11 mo) --> First molar (16 mo) --> Canine (19 mo) --> Second molar (29 mo)
Mandibular:
Central (8 mo) --> Lateral (13 mo) --> First molar (16 mo) --> Canine (20 mo) --> Second molar (27 mo)
46
General features of the primary dentition
- Developmental spacing
- Flush terminal plane molar relationship
- Dental arches ovoid in shape
- Deep bite present initially that changes to edge-to-edge
- Flat curve of spee
47
Developmental spacing
- Maxillary spacing -- 70% of children
- Mandibular spacing - 63% of children
* *Primary dentition without spacing will be followed by crowding of the permanent dentition in 40% of children
* * Baume type 1: spacing
* * Baume type 2: no spacing
48
Primate space
Maxillary: between lateral incisors and canine
Mandibule: between canine and first primary molar
49
Primary molar relationship
Flush terminal plane --> 76% of children (distal of maxillary primary second molar flush with distal of mandibular primary second molar)
Mesial step --> 14% of children
Distal step --> 10% of children
50
Early mesial shift
- Closing of interdental space between primary molars prior to eruption of first permanent molars
- Affects mandibular primate space
- Convert flush terminal plane to mesial step
- Approximately age 4
51
First inter-transitional period (primary dentition)
- The period between the completion of the primary dentition and the emergence of the first permanent tooth
- Vertical skeletal growth
- Deepening of the bite due to attrition of the primary incisors
52
Orthodontic implications of first inter-transitional period (primary dentition)
- Close/non-spaced dentitions have increased risk of crowding
- Distal step molar relationship should be evaluated for class II malocclusion
- Mesial step molar relationship should be monitored for the development of class III malocclusion
- Closed/non-spaced dentitions have a decreased probability of converting to class I molar relationship if initially distal step or flush terminal plane
53
Eruption sequence of permanent dentition
Maxillary: First molar (6-7 years) --> central (7-8 years) --> lateral (8-9 years) --> first premolar (10-11 years) --> second premolar (10-12 years) --> canine (11-12 years) --> second molar (12-13 years)
Mandibular: First molar (6-7 years) --> central (6-7 years) --> lateral (7-8 years) --> canine (9-10 years) --> first premolar (10-12 years) --> second premolar (11-12 years) --> second molar (11-13 years)
54
First transitional period (mixed dentition)
- From ages 6-8 years
- Eruption of first permanent molars
- Replacement of incisors
55
Incisor liability
- Permanent incisors are larger than primary incisors
- 7.6 mm in maxilla
- 6 mm in mandible
56
Compensation for incisor liability
- Interdental spacing in primary dentition --> maxillary primate space
- Labial eruption of permanent incisors --> Increased proclination of permanent incisors
- Increased intercanine width --> 4mm in maxilla, 2-3mm in mandible
57
Orthodontic implications of first transitional period (mixed dentition)
- "Shark teeth"
- Lingually erupting mandibular incisors --> 10-20% prevalence
- Closed primary dentition
58
Second inter-transitional period (mixed dentition)
- From age 8 to 9 or 10 years
- From the complete eruption of incisors until the beginning of replacement of primary canines and molars
- Maxillary arch --> 1) "ugly duckling" stage, 2) diastema, 3) loss of primate space, 4) excess overjet
- Mandibular arch --> 1) transitional crowding, 2) loss of primate space
- Vertical skeletal growth
- Bone remodeling in maxillary tuberosity and mandibular ramus
- Development of maxillary canines
59
Orthodontic implications of second inter-transitional period (mixed dentition)
- Mild mandibular crowding (<2mm) can resolve spontaneously
| - Maxillary diastema has a high likelihood of resolving spontaneously --> wait until maxillary canines erupt to reassess
60
Second transitional phase (mixed dentition)
- Occurs between 10-12 years of age
- Replacement of primary canines and molars
- Leeway space
- Late mesial shift
- Closure of maxillary diastema
61
Leeway Space
Difference in the mesiodistal dimension between primary canine and molars and permanent canines and premolars
62
Average values for leeway space
Maxillary leeway space
- 2.2 mm (Bishara)
- 1.8 mm (Nance)
Mandibular leeway space
- 4.8 mm (Bishara)
- 3.4 mm (Nance)
63
Late mesial shift
** Late mesial shift = Leeway space
- Mesial movement of first permanent molars after exfoliation of the primary molars
- Closure of the leeway space
64
Late mesial shift and arch length
Maxilla: arch length greatest in mixed dentition (8-10 years), then decreases
Mandible: arch length greatest before early mesial shift (age 4 then continues to drop off
**Arch length decreases 2-3 mm
65
Closure of maxillary diastema
Arch length greatest before early mesial shift (age 4) then continues to drop off
66
Orthodontic implications of second transitional phase (mixed dentition)
- Leeway space may be used to address incisor liability
- Late mesial shift can help transition to a class I molar relationship from end on
- Maxillary diastema should be reassessed once permanent canines have erupted
- Moderate to severely crowded mixed dentition cases will have a lower likelihood of transitioning from class I molar relationship from class II
67
Permanent dentition
- From age 12 to adulthood
- Onset of adolescent growth spurt
- Finalization of molar relationship
68
Transverse dimension and adolescent growth spurt
Completed prior to growth spurt
69
Vertical dimension and adolescent growth spurt
Continues beyond growth spurt
70
Anterior-posterior dimension and adolescent growth spurt
Continues throughout growth spurt
71
Adolescent growth spurt additional changes
- Profile changes occur as changes in specific locations take place
- Frontal bone, brow, nose, and chin becomes more prominent
- Continued lowering of the palatal vault
- Vertical maxillary growth is often greater in females
72
Context of adolescent growth spurt
Modifying growth of the craniofacial structures might help to address malocclusion of skeletal origin
73
Implications of growth spurt
- Skeletal malocclusion
- Timing of growth modification
- Timing of surgery
- Dental interventions
- Timing of implant placement
74
Mandible and growth spurt
- Mandible demonstrates a pubertal growth peak
| - Allows for additional change in molar relationship
75
Distal step can develop into
- Class II
| - End to End
76
Flush terminal plane can develop into
- Class I
| - End to end
77
Mesial step can develop into
- Class I
| - Class III
78
How do we know when the growth peak will occur?
Developmental age --> biological age --> morphologic, skeletal, dental, circumpubertal
79
Somatotypic age
- Ectomorph
- Mesomorph
- Endomorph
Maturation: endomorph -> mesomorph -> ectomorph; no prediction in timing of growth spurt?
80
Height and weight and growth spurt
- Absolute height and weight not accurate predictors
81
Height velocity/growth peak
Prepubertal growth peak --> age 6-7
Pubertal growth peak -->
- Age 11.5 in females
- Age 14.5 in males
82
Dental age and developmental age
- Dental age generally does not correlate well with developmental age
- Variation in timing of eruption
83
Stages of canine calcification (compared to hand wrist radiograph)
D --> E --> F --> G --> H
84
Stage D of canine calcification
- Crown formation is completed down to the cemento-enamel junction
- The superior border of the pulp chamber in the uniradicular tooth has definite curved form, being concave towards the cervical region. The projection of the pulp horns, if present, given an outline shaped like an umbrella top.
- Beginning of root formation is seen in the form of a spicule.
85
Stage E of canine calcification
- The walls of the pulp chamber now form straight lines whose continuity is broken by the presence of the pulp horn, which is larger than the previous stage.
- The root length is less than the crown height.
86
Stage F of canine calcification
- The walls of the pulp chamber now form a more or less isosceles triangle. The apex ends in a funnel shape.
- The root length is equal to or greater than the crown height.
87
Stage G of canine calcification
The walls of the root canal are now parallel and its apical end is still partially open
88
Stage H of canine calcification
- The apical end of the root canal is completely closed.
| - The periodontal membrane has a uniform width around the root and the apex.
89
Skeletal age
More highly correlated with menarche than height, weight, or growth velocity
90
Hand wrist radiographic evaluation techniques
- Tanner and Whitehouse method
| - Bjork, Grave, and Brown method
91
Stage 1 of Bjork, Grave, and Brown method
3 years before pubertal growth spurt
92
Stage 4 of Bjork, Grave and Brown method
Beginning of pubertal growth spurt
93
Stage 5 of Bjork, Grave, and Brown method
Peak of pubertal growth spurt
94
Stage 6 of Bjork, Grave, and Brown method
End of pubertal growth
95
Cervical vertebrae maturation stage 1 (McNamara, Franci, Bacetti)
Peak mandibular growth will occur 2 years ager this stage
96
Cervical vertebrae maturation stage 2 (McNamara, Franci, Bacetti)
- Peak mandibular growth will occur 1 years after this stage
| - Early class III treatment with facemask should take place before this stage
97
Cervical vertebrae maturation stage 3 (McNamara, Franci, Bacetti)
- Peak mandibular growth will occur within 1 year of this stage
- Early class II treatment with functional appliances should take place at this stage
- Treatment of vertical malocclusion also
98
Cervical vertebrae maturation stage 4 (McNamara, Franci, Bacetti)
Peak mandibular growth has occurred 1-2 years prior to this stage
99
Cervical vertebrae maturation stage 5 (McNamara, Franci, Bacetti)
Peka mandibular growth has ended 1 year prior to this stage
100
Cervical vertebrae maturation stage 6 (McNamara, Franci, Bacetti)
Peak mandibular growth has ended 2 years prior to this stage
101
Arch length changes
- Early mesial shift decreases arch perimeter
- Eruption of incisors results in crowding
- Labial eruption of maxillary incisors can increase arch perimeter
- Leeway space can allow for relief of crowding
- Late mesial shift decreases arch perimeter
102
Anterior posterior changes
Distal step --> develops into class II
Flush terminal plane --> converts to class I (56%), class II (44%)
Mesial step (>2 mm) --> converts to class I (68%), converts to class II (13%), converts to class III (19%)
* ** Class I - 61.6%
* ** Class II - 34.3%
* ** Class III - 4.1%
103
Transverse changes
Intercanine width is complete:
- - Mandible --> 9-10 years; earlier for girls than for boys
- - Maxilla --> 12 years in girls, 18 years in boys
104
Favorable eruption sequence
Maxilla: 6, 1, 2, 4, 5, 3, 7 (Canine near to last)
Mandible: 6, 1, 2, 3, 4, 5, 7
105
Planes of Space
- Anterior posterior
- Vertical
- Transverse
- Alignment
106
AP dimension
- Angle classification of molars, canines, incisors
- Overjet --> anterior crossbite
- Incisor angulation
- Anteroposterior incisor portion
107
Class I malocclusion
Molars normal, but malposed teeth
108
Class II malocclusion
Lower molar distally positioned relative to the upper
109
Class III malocclusion
Lower molar mesially positioned relative to the upper
110
Overjet definition
Horizontal overlap of incisors measured from labial surface of lower incisor to Invisalign tip of upper incisor
111
Overjet values
- Normal = 2-3mm
- Larger than normal OJ
- Negative OJ
- End on incisors when OJ = 0
112
Class II Incisor Divisons
- Division 1: Flared incisors
- Division 2: Retroclined incisors
* -trusive refers to position
* -clined refers to angulation
113
Vertical measurements
- Overbite
- Incisor display
- Gingival display
- Curve of spee
- Occlusal cant
114
Overbite definition
Vertical overlap of the incisors
115
Measurements for Overbite
- Normal is 1-2mm or 20-30%
- Excessive OB = deep bite, possibly with palatal impingement
- No overbite = open bite
116
Transverse (items to consider)
- Midlines
- Posterior crossbite
- Arch width
- Arch symmetry
- Curve of Wilson
117
Alignment (items to consider)
- Crowding/arch length deficiency
- Missing teeth
- Supernumerary teeth
- Impacted teeth
- Transposed teeth
- Ankylosed teeth
- Diastema
- Bolton analysis/tooth size discrepancy
118
Crowding/arch length deficiency
Space analysis: comparison between the amount of space available and the amount of space required
119
Steps of space analysis
Step 1: measure available space by dividing the arch into segments that can be measured as straight lines
Step 2: calculate the amount of space required for the alignment of teeth; measure MD width of each tooth from contact point to contact point
120
Mixed dentition analysis
- Not necessary in the primary dentition
- Useful in the mixed dentition
- Should have permanent incisors and molars
121
Direct measurement (mixed dentition analysis)
- Measure unerupted teeth on radiographs
- Account for magnification errors
(True width of primary molar/apparent width of primary molar) = (True width of unerupted premolar/apparent width of unerupted premolar)
**Compare space required with space available**
122
Tanaka and Johnston Method (mixed dentition analysis)
- Mandibular incisors must be erupted
- Predicts underused permanent canines and premolars
**one half the mesiodistal width of the four lower incisors + 10.5mm = estimated width of Mandibular canine and premolars (one quadrant)
**one half the mesiodistal width of the four lower incisors + 11.0mm = estimated width of maxillary canine and premolars (one quadrant)
[Compare space required with space available]
123
Moyers prediction values (mixed dentition analysis)
- Mandibular incisors must be erupted
- Predicts underused permanent canines and premolars
- Based on a ratio of Mandibular incisor widths to canine and premolar widths
124
Tooth size discrepancy
- The degree of disproportion in the size of individual teeth
- About 5% of the population have some degree of tooth size discrepancy
- The most common teeth are the upper lateral incisors and 2nd premolars
- For good class I occlusion with ideal OB and OJ, teeth must be proportional in size
125
Bolton Analysis
Ideal ratio of the mandibular to maxillary teeth
- Sum mandibular 12/Sum maxillary 12 x 100 = 91.3
- Sum mandibular 6/sum maxillary 6 x 100 = 77.2
126
Cephalometric Analysis
- Used to compare the patient to a normal reference group, so that differences between the patient’s actual dentofacial relationships and those expected for his or her racial or ethnic group are revealed
- Helps diagnose if a skeletal discrepancy exists and if so, if it is due to the maxilla, mandible, or both
127
Different types of cephalometric analyses
- Steiner
- Ricketts
- Sassouni
- Wits
- Harvold
- McNamara
- Cohen
- Cutcliffe
- Burstone
- Jarabak
- Downs
- Bergman
128
Steiner Analysis
- Developed in 1950s by Cecil Steiner
- Can be considered the first modern cephalometric analysis for two reasons:
1) It displayed measurements in a way that emphasized not just the individual measurements but their interrelationship into a pattern
2) It offered specific guides for use of cephalometric measurements in treatment planning
129
What is the most widely used cephalometric analysis today?
Steiner Analysis
130
What were the ideal measurements of Steiner Analysis based off of?
Original ideal measurements were reputedly based on one Hollywood starlet
131
SNA
- Sella-nasion-A point
| - Norm = 82 degrees
132
SNB
- Sella-nasion-B point
| - Norm = 80 degrees
133
ANB
- Norm = 2 degrees
134
Relationship of the upper incisor to the NA line
* -clined = angulation
* -trusive = bodily position
* 1-NA (mm) norm = 4mm
* 1-NA (deg) norm = 22 deg
135
Relationship of the lower incisor to the NB line
* 1-NB (mm) norm = 4 mm
| * 1-NB (deg) norm = 25 deg
136
Interincisal angle
Norm 1-1 = 131 deg
137
Mandibular plane to Sella-Nasion Plane
* GoGn-SN angle
| * Norm = 32 deg
138
Dolichofacial
* GoGn-SN > 32 deg
| * Steep open bite, with mandibular plane greater than 32
139
Brachyfacial
* GoGn-SN < 32 deg
| * Deep bite, mandibular plane is less than 32
140
Occlusal plane to SN (angle)
• Norm = 14 deg
141
Treatment of skeletal problems
• The mindset:
- Skeletal solutions for skeletal problems is considered ideal
- Dental solutions for skeletal problems is considered camouflage or compromise
• Growth modification vs surgery
142
Treatment of skeletal problems: Maxilla
* Encourage growth in the transverse dimension
* Encourage growth in the anteroposterior dimension
* Discourage growth in the anteroposterior dimension
* Discourage growth in the vertical dimension
143
Treatment of skeletal problems: Mandible
* Encourage growth in the anteroposterior dimension
* Discourage growth in the anteroposterior dimension
* Discourage growth in the vertical dimension
144
How to encourage maxillary growth when transverse deficiency is present?
• Create tension in the mid palatal suture:
- Quad helix
- W Arch
- Banded Hyrax Expander (RPE)
- Banded Haas Type Expander (RPE)
- Schwartz Appliance
- Crozat Appliance
145
Encouraging maxillary growth modification in anterior-posterior dimension
* Encourage maxillary growth in the AP
* Create tension in circum-maxillary sutures
* Allow normal mandibular growth
* Retrognathic maxilla — think prior to age 10
146
Device for maxillary protraction
Facemask/protraction headgear
147
Discouraging maxillary growth in anterior-posterior dimension
* Restrain maxillary growth
* Create pressure in circum-maxillary sutures
* Allow normal mandibular growth
* Prognathic maxilla
148
Device to discourage maxillary growth in AP dimension
Headgear
149
Headgear components
```
• Facebow with:
- Inner bow
- Outer bow
• Neck/head strap
• Bilateral attachments
```
150
Types of headgear
• Parietal pull (direction of pull is superior)
• Cervical pull (direction of pull is inferior)
• Occipital pull
(direction of pull is in between parietal and cervical)
151
Encouraging mandibular growth in the anterior-posterior
- Mandibular growth modification:
• Encourage mandibular growth
• Modify the function of the mandible
- Functional matrix theory (hypothesis)
152
Functional appliances that aid in mandibular growth modification
* Bionator
* Twin block
* Herbst
* Fixed/removable Herbst
* Banded Herbst
* SSC Herbst
* MARA - Mandibular anterior repositioning appliance
153
Discouraging mandibular growth in the anterior-posterior dimension
• Mandibular growth modification
- Discourage mandibular growth
- Restrain growth in the condylar cartilage and periosteum
154
Mandibular restraint device
Chin cup/chin cap
155
Factors associated with prolonged sucking habits
* Older maternal age
* Higher maternal education level
* Having no older siblings
156
Pacifier, thumb habit facts
* Most will quit by 3 or 4 (years?)
* Pacifier before thumb habit ceased
* Aim: Spontaneous cessation first then intervention
157
Pacifier habit results in?
Posterior crossbite
**among others
158
Digit sucking habit results in?
Excessive OJ
**among others
159
Timing of intervention
• Opportunity for spontaneous cessation
• Prior to eruption of permanent teeth
- Since problems arise by age 4, consider intervention by 3-4 yo
• Psychosocial health
160
Treatment for non-nutritive sucking
* Counseling
* Reminder therapy
* Reward system
* Adjunctive therapy
161
Pacifier cessation
• Earlier than digit habits
- 90% before age 5
- 100% before age 8
• Theoretically easier due to parental control
• May result in transfer of habit to digit
162
Lip habits
* Lip licking
* Lip sucking
* Lip biting
163
Tongue thrust impact
Anterior open bite
• However, epidemiological studies indicate a higher percentage of people with tongue thrust than those with open bite
164
Diagnosis: tongue thrust
Discriminate between:
• Passive anterior tongue posture
AND
• Active thrust on swallow
- Atypical swallow
- “Opportunistic behavior”
165
Treatment for tongue thrust
```
• Appliance therapy
- Tongue crib
• Exercises (myofunctional therapy)
- Swallowing in front of mirror
- Hold mint in roof of mouth
- Tongue clicks
```
166
Impact of mouth breathing
• Long lower face
• Maxillary constriction
• “Adenoid fancies”: AKA long face syndrome, refers to the long, open-mouthed face of children with adenoid hypertrophy
• Unreliable definition and identification of habitual mouth breathers:
- Cannot be considered causative: 1) Normal for 3-6 year old children to be lip incompetent, 2) roughly equivalent percentage of nasal and oral breathers before age 8
167
Treatment for mouth breathing
• Mouth breathing resulting from airway obstruction
- Medical management of airway
- Turbinectomy
- Adenoidectomy
168
Nail biting
* Rare in children younger than 3 to 6 years
| * Suggested as a manifestation of stress
169
Impact and treatment for nail biting
Impact:
• No evidence of impact on occlusion
• Possible enamel fractures
Treatment:
• none recommended
170
Bruxism impact
* Wear of primary canines and molars — rare effect on pulp
| * Muscle soreness and TMJ pain
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Cause of bruxism
Localized cause:
• Occlusal interference
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Systemic cause:
• Intestinal parasites
• Subclinical nutritional deficiencies
• Allergies
• Endocrine disorders
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Psychological cause:
• Personality disorder
• Increased stress
Medical cause:
• Musculoskeletal disorders
• Mental retardation
172
Treatment for nail biting
* Identification and equilibration of occlusal interferences
* Rule out systemic problems
* Mouth guard
* Stainless steel crowns as needed
* Referral to therapist for psychological evaluation
173
Etiology of premature tooth loss
* Caries
* Trauma
* Ectopic eruption
* Congenital disorders
* Arch length deficiencies resulting in resorption
174
Problem of premature tooth loss
Early loss of primary teeth may impact the alignment of permanent teeth.
175
Early loss of primary incisors
• Usually due to caries or trauma
• Minimal loss of arch length
- Exceptions: very early loss, no spacing. Class II tendency, deep overbite
• Minimal impact on masticatory function
• Possible impact on speech
- Lingual-dental sounds (s, z, th)
- Especially prior to the development of speech skills
• < 2 years of age —> possible space loss
• > 2 years of age —> esthetic problem (for parents)
176
Early loss of canines
• Usually due to arch length deficiencies resulting in resorption by incisors
• No detectable relationship with posterior alignment
• Accompanied by lateral shift of incisors and midline shift
- If bilateral, accompanied by lingual tipping
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Early loss of primary first molars
• Usually due to caries
• Canine and incisor dislocation toward the extraction site
- ~1.5 mm in mandible
• Mesial movement of primary second molar
- ~1 mm in maxilla
• Mesial eruption of maxillary first premolars
- Blocked out canines
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Early loss of primary first molars - space loss vs arch width/length/perimeter
• No statistically significant loss of arch width, length and perimeter in the primary dentition
VERSUS
• Minor space loss
- Less space loss after eruption of permanent first molars
- Better intercuspation reduces space loss
179
Early loss of primary second molars
* Usually due to caries, sometimes due to ectopic eruption of permanent first molar
* Arch length reduction
* Blocked out second premolar
180
Important points regarding space loss
* Space loss often occurs before extraction (?)
| * Greatest space loss usually occurs between 4-8 months after extraction
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Impact of early tooth loss on occlusion (differences)
Differences:
• Mandibular effects worse than maxillary
• Second primary molar effects worse than first
• Earlier tooth loss worse than later
• Tooth loss in crowded arches worse than in spaced
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Impact of early tooth loss on occlusion (summary)
* Premature loss of primary teeth correlates with increasing likelihood of orthodontic treatment
* Premature loss of primary incisors and canines does NOT affect posterior occlusion
* Premature loss of primary canines MAY affect anterior alignment
* Premature loss of primary molars MAY affect posterior occlusion
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Fixed unilateral space maintainers
Band and loop:
• Band cemented around one abutment tooth
• Loop contacts another abutment tooth
Distal shoe:
• Premature loss of the primary second molar with an unerupted permanent first molar
• Band, distal extension, subgingival blade
• Requires an incision site
• Contraindicated in patients with poor oral hygiene, lack of cooperation, or medical conditions
Reverse band and loop:
• Loop faces distal
• Band is on the primary first molar
• Alternative to the distal shoe
Prefabricated space maintainers:
• Denote
• Appliance therapy group
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Fixed bilateral space maintainers
Lower lingual holding arch:
• Bands cemented around primary second molars or permanent first molars
• Wire arch connecting molars and contacting mandibular incisors
Trans palatal arch:
• Bands cemented around primary second molars or permanent first molars
• Wire arch connecting molars
Nance holding arch:
• Bands cemented around primary second molars or permanent first molars
• Wire arch connecting molars with acrylic button connecting hard palate
Groper appliance:
• Mesh bonding base soldered to lingual arch
• Plastic denture tooth adapted and bonded to mesh base
** Can also be done as crown groper alliance with abutment teeth having SSCs
185
Removable space maintainer
* No single classic appliance
* Involves creativity
* Retentive features
* Acrylic to hold occlusion and fall the space
* Fill the saddle to encourage eruption behind the acrylic
186
Arch length discrepancy formula
Space available - space required = arch length discrepancy
187
Potential solutions for crowding
* Change space available
| * Change space required
188
How to change space available
* Distalize molars
* Procline incisors
* Expand palate
* Upright posterior teeth
189
How to change space required
• Interproximal reduction
• Extract teeth
- Single tooth
- Four premolars
190
Treatment options for crowding
Less than 4mm:
• Non-extraction (change space available)
5mm to 9mm:
• Non-extraction or extraction (depending on facial esthetics, incisor position, etc.)
Greater than 10mm:
• Extraction (change space required)
191
Serial extraction
* “A planned sequence of tooth removal [to] reduce crowding and irregularity during the transition from the primary to the permanent dentition”
* Extraction of primary canines, primary first molars, first premolars (Cs, Ds, and 4s)
* Allows permanent teeth to erupt over the alveolus and through keratinized tissue, rather than being displaced buccal or lingually
192
Result of early extraction of Cs
* Delayed eruption of 3s
| * Early eruption of 4s
193
When is the serial extraction protocol initiated?
• Mixed dentition:
- Minimizes the amount of tooth movement
- Allows permanent teeth to erupt in better position
