Transverse Problems Flashcards
what is the prevalence of anterior crossbites
2.2%-11.9%
when is the anterior crossbite manifested
in the mixed dentition
what is the result of no tx of an anterior crossbite
- esthetic problem
- damage to the teeth in crossbite through attrition
- gingival recession
- loss of alveolar bone on lower incisors
- excess mobility of lower incisors affected by the crossbite
what is the DDX for anterior crossbite
- cepahlometric evaluation
- dental assessment: class III molar relationship
- negative overjet or end to end relationship with retroclined mandibular incisors (compensated class III malocclusion)
- if negative overjet, proceed to functional assessment
- functional assessment: determine whether a centric relation/centric occlusion discrepancy exists
what might an anterior crossbite DDX patient have in the functional assessment of CR and CO
- at CR, patient may have a class I skeletal pattern, normal facial profile and class I molar relationship
- at CO, patient may have a class III skeletal and dental pattern
what is examined in the DDX for anterior crossbite
- cephalometric evaluation
- dental assessment
- functional assessment
- profile analysis
if the pt has a class III molar relationship with negative overjet what do you need to do
a functional assessment- see if there is a CR CO discrepancy
- if no CR CO discrepancy -> true class III malocclusion
- if there is a CR-CO shift -> pseudo class III maloclussion
what do you do if a pt is in a pseudo class III relationship
eliminate CR CO shift
what happens if you eliminate a CR CO shift in pseudo class III
you get a class I molar relationship -> class I malocclusion or a class III molar and you get a compensated class III malocclusion
what is a class III molar with positive overjet and retroclined mandibular incisors
compensated class III malocclusion
in an anterior cross bite what should the ceph show you in the skeletal
class III maxillo mandidular relationships
in an anterior cross bite what would the ceph show you in the dental
class I or II maxillo-mandibular relationships
in an anterior crossbite what would the dental eval show you about the skeletal
- severe proclination of upper incisors
- severe retroclination of lower incisors
- class III molar relationships
- may or may not be present in class III skeletal
in an anterior crossbite what would the dental exam show you about dental relationship
- normal inclination/position or severe retroclination/retrusion of upper incisors
- severe proclination/protrusion of lower incisors
- class I or II molar relationship
- presence of anterior functional shift
- may or may not be present in class III dental
what would the profile exam tell you about the skeletal relationship in an anterior crossbite
concave or straight
- may or may not be present in class III skeletal
what would the profile exam tell you about the dental in an anterior crossbite
straight or convex
what is the most common etiologic factor for nonskeletal anterior crossbites
lack of space for the permanent incisors
what should the tx plan be focused on for the early treatment of dental anterior crossbite
on management of the total space situation, not just the crossbite
what is the management of early tx of dental anterior crossbite
- extraction of adjacent primary teeth to provide necessary space
- disking of teeth
- opening space for tooth movement
- determine whether tipping will provide appropriate correction
what are the treatment modalities for anterior crossbite
- fixed inclined planes
- reverse crown
- maxillary lingual holding arch with springs
- removable appliance with jackscrew
- 2x4 appliance
what is a reverse crown
a large permanent anterior tooth crown is reverse cemented
what is the purpose of a maxillary lingual holding arch with springs
lingual eruption of maxillary lateral incisors in a crowded arch
what should the general dentist do for an anterior crossbite
refer to orthodontist
what is the objective of anterior crossbite tx
reduce the amount of dental compensation to skeletal; discrepancy that are often associated with a more severe malocclusion in late adolescence
where are abutments for the 2x4 appliance placed
on first molars and maxillary incisors
what is the prevalence of the posterior crossbite
- 7.3% of hispanic population
- 9.6% in african american populations
- 9.1% among caucasians
what is a cause of the posterior crossbite and what is it
- transverse maxillary deficiency: narrow maxilla relative to the rest of the face
what happens in the hidden posterior crossbite
- compensatory changes in dentoalveolar processes
- tipping of maxillary teeth to the buccal
- tipping of mandibular teeth to the lingual
- uprighting teeth creates a dental crossbite
a unilateral posterior crossbite may be:
a bilateral crossbite with a functional lateral jaw shift as the teeth from centric relation to centric occlusion
what is the key sign of unilateral posterior crossbites
- deviation of the mandibular dental midline, relative to the maxillary dental and skeletal midlines, toward the side of the crossbite when the teeth are in MI
what are the sequelae to posterior crossbites due to functional shifts not being treated
- compensatory changes in the TMJ - no strong evidence
- modifications of soft tissue growth - no strong evidence
- development of skeletal asymmetries - no strong evidence
- attrition of teeth
do posterior crossbites due to functional shifts self correct
no
what needs to be considered for posterior crossbite management?
- is the crossbite skeletal or dental
- is the crossbite unilateral or bilateral
- is there a functional shift
- if dental, which teeth are tipped and in which jaws
- should the treatment be initated at this time or deferred to a later date
- should the problems be corrected
- can the problem be corrected or masked by treatment
how is a posterior cross bite managed
- simple dentoalveolar unilateral posterior cross bite: fixed or removable appliances to move teeth
- W-arch, quadhelix
- jackscrew
what ages do you use the W-arch, quadhelix for
up to age 9 or 10
what does the jackscrew do for the posterior cross bite
relatively heavy force that separates the partially interlocked suture
where is the anchorage and rate of expansion for rapid palatal expansion
- posterior teeth
- 0.5-1.0mm/day
where is the anchorage and rate of expansion for slow palatal expansion
- posterior teeth
- 1.0mm per week
where is the anchorage and what is the rate of expansion for implant supported expansion
- maxilla- bone screws
- slow or rapid
what expansion do you use in the early mixed dentition
slow expansion
suture can be separated in females up to age:
16
suture can be separated in males up to age:
18
what radiograph is used to assess the midpalatal suture patency
an occlusal radiograph
what is another name for the buccal crossbite
scissor bite
what is a scissor bite
buccal displacement of a maxillary posterior tooth, with or without contact between the lingual surface of the maxillary lingual cusp and the buccal surface of the mandibular antagonist’s buccal cusp
what is a complete buccal crossbite and what isa another name for it
- Brodie bite
- a combination of excessive maxillary width and a narrow mandibular alveolar process, although the width of the mandibular base is usually normal
what is a scissor bite treated with
- elastics
- mandibular appliance to upright posterior teeth
- lip bumber
