Cephs and Occlusion Flashcards
How does a lateral ceph aid in the dx of a malocclusion?
Skeletal relationship
dental to skeletal relationship
Denture to denture relationship
Soft tissue relationship
SNA: definition and norm?
Position of maxillary apical base (norm 82 deg)
SNB: definition and norm?
Position of mandibular apical base (norm 80 deg)
ANB: definition and norm?
Anterior-posterior position of bases (norm 2 deg)
SND: definition and norm?
Position of mandible: norm 76
GoGn-SN: a measure of what? definition? norm?
Line between gonian-gnathion
A measure of growth
Mandipular plane relates to the facial pattern
norm 32 degre
Occlusal Plane - SN
Similar to mandibular plane
Measure of growth
norm of 14
SNA : what indicates pro or retrognatism? (which arch)?
Maxillary prognatism is greater than 82
Maxillary retrognathism is less than 82
SNB: what indicates pro or retrognatism? (which arch)?
Mandibular prognathism: greater than 80
mandibular retrognathism: less than 80
What are two measures of hyper or hypodivergent?
GoGn-SN (greater than 32-hyperdivergent) Occlusal Plane (greater than 14 hyperdivergent)
Soft tissue analysis: Nasolabial angle (formed by, normal?) Lip Position (formed by, normal?)
Nasolabial angle: base of the nose to the upper lip
norm 100-110 degrees. If too small, maxilla/max incisors are too forward.
Lip position: Tip of the nose to soft tissue pognonion, the lower lip should be about 2 mm behind the E line, maxillarly lip should be on it.
Facial growth patterns: describe the direction over time, the pattern, and correlation with somatic growth
The face grows downward and forward.
- facial form and pattern tends to maintain
- Differential growth of different parts of the face. Face tends to ‘flatten’ over time.
How does facial/jaw growth correlate to the body growth or growth spurt?
Facial growth generally corresponds to somatic growth, the jaw does not really have a “growth spurt” in 75% of people.
- The correlation between somatic spurt w/jaw growth is only 25% therefore, treatment initation should be dictated by severity not growth spurt
Brachyfacial: describe, growth tendency, treatment reasoning? Headgear choice?
Hypodivergent/Short - Excessive condlyar growth tendency - flat mandibular plan and deep bite Counter clockwise growth rotation - deep bite typically favors non-extraction, encouraging posterior extrusive force and anterior intrustion forces - cervical pull headgear
Dolichofacial: describe, common clinical findings, alternate name, treatment favors? headgear choice?
Hyperdivergent
- Open bite sensitivity, typically favors extraction therapy avioding posterior extrusion
- Common clinical findings: gummy smile, open bite, lip incompetence, steep mandibular plane
- high pull headgear- intrudes posterior teeth
Considerations when determinging the timing of treatment
- nature and etiology of malocclusion
- Severeity of skeletal discrepancy
- Presence of functional shift
- Stage of dental development
Extreme growth patterns are difficult to predict, while more normal cases are easier. T/F
False: extreme growth patterns are easier to predict
Predentate infants:
gum pad ‘molar’ relationship?
Describe the VDO
Infant profile?
Gum pad relationship reflects a normal maxillary/mandibular relationship
- There is a lack of alveolar development therefore there is a decreased vertical dimension and a shallow palatal vault
- Retrognatic profile is normal in the infant
What are the primary molar relationships from most to least common and percents
Mesial step 60%
Flush terminal plane 30%
Distal step 10%
Flush terminal plane, what 3 factors are needed in order to become class 1 relationship?
- Mesial growth of mandible
- Early mesial shift closure of generalized posterior spacing with eruption of 1st permanent molars
- Late mesial shift- mesial drift of mandibular 1st permanent molars into leeway space
Distal step? What percentage of children have this relationship and what percent develop into class I, II or III?
23% have distal step, 100% of those with distal step end up with a class II relationship
Flush Terminal plane: What percentage of children have this relationship and what percent develop into class I, II or III?
30% of children have Flush terminal plane, of those 56% become class I while 44% become class II.
What percentage of children develop class I, II, III molar relationships?
Class I : 60%
Class II: 35%
Class III: 5%
Which primary molar relationship has the greatest probability of becoming a class I molar relationship?
Mesial step