Treatment Tactics

Question 1

Under what circumstances should a maxillary expansion appliance be used?

Answer 1

Correction of dental and/or skeletal posterior crossbite that is unilateral or bilateral

Correction of anterior crossbite assocaited with functional shift

Elimination of crowding through increase of arch length

Correction of axial inclinations of posterior teeth

Mobilization of circumaxillary sutures to make skeletal protraction possible during face mask treatment

Question 2

What are some of the different types of expansion appliances?

Answer 2

Hyrax - two bands on upper first molars and two pandas on upper first bicuspids. Incorporates as many teeth as possible to minimize buccal crown torque. (Excessive buccal crown torque should be avoided since it can result in adverse periodontal sequelae, relapse, and lingual interferences

Haas - fixed expander that uses acrylic pads and heavy lingual wires to apply pressure to both teeth and palatal tissue. Supposedly reduces buccal tipping

Bonded RPE - uses posterior acrylic coverage and is directly bonded to teeth. The posterior blocks remove occlusal interferes and discloses anterior teeth

Schwartz (removable)
Fixed mandibular 
Quadhelix 
W arch
Pendex 
Lip bumper

Question 3

What is a pendex expander?

Answer 3

A fixed expansion appliance that is also used to distalize an derotate on or both upper first molars

It eliminates patient compliance concerns from the distalization treatment objective

Question 4

Expansion in skeletally mature patients may result in ____; therefore, the best time to correct these constricted arches is usually…

Answer 4

Undesired dental movements

In the mixed dentition

Question 5

Correction of a class 2 malocclusion using nonextracion orthodontic treatment with fixed appliances requires the ___ of ___teeth and/or ___ movement of the ___ teeth.

How can these movements be accomplished?

Answer 5

Distalization of maxillary teeth

Anterior movement of mandibular teeth

Maxillary teeth can be distalized using extra-oral forces (J-hook headgear or facebow) or intraoral forces (class 2 elastics or appliances such as the distal jet or pendulum appliance) using the lower arch as anchorage

Question 6

When should extra-oral traction therapy be initiated?

Answer 6

In mixed dentition if a skeletal effect is desired

It may also be used in pts who are not growing if only tooth movement or anchorage is the goal

Question 7

What are the indications for class 2 elastics?

Answer 7

Class 2 molar or canine dental relationship

Finishing orthodontic cases to achieve anterior coupling

Excessive overbite (deep bite)

Orthognathic facial profile

Question 8

When are class 2 elastics contraindicated?

Answer 8

Class 3 skeletal discrepancy

Dental open bite or skeletal open bite tendency

Insufficient wire dimension to resist extrusion of teeth associated with use of class 2 elastics

Excess lower anterior facial height

Question 9

What are the three basic ways to correct crowding problems?

Answer 9

Expansion of the dental arches, including distalization of the posterior segments of the dental arch

Extraction of permanent tooth mass

Reapproximation to reduce the MD width of selected teeth

Question 10

Crowding as a result of space loss is usually due to either __ or ___

Answer 10

Ectopic eruption of the first molars

Early loss of one or more primary teeth

Question 11

If there is loss of arch length, the clinician must decide to either ___ or ___.

Answer 11

Regain the lost space (usually best to proceed with treatment ASAP)

Maintain the remaining space

Another option is to defer treatment in anticipation of extracting permanent teeth

Question 12

Ectopic mesial eruption may necessitate…

Answer 12

The early removal of second deciduous molars in order to allow full eruption of the permanent first molars before regaining the lost arch perimeter

Question 13

What is serial extraction?

Answer 13

Serial extraction is the selected removal of both deciduous and permanent teeth (usually the first premolars) in order to allow severely crowded teeth to erupt into more desirable positions.

Sequential removal of primary teeth and permanent teeth is typically followed by comprehensive orthodontic treatment after eruption of permanent teeth.

Question 14

What are the indications for serial extractions?

Answer 14

Minimum 7mm of crowding in the anterior areas per arch

Coincident upper and lower mid lines

Bilateral class 1 molar relationship

Balanced skeletal pattern in all three planes of space

Question 15

What are some complicating factors for serial extractions?

Answer 15

Class 3 molar relationships

Class 2 molar relationships

Unbalanced skeletal patterns of any kind

Unequal crowding in maxillary and mandibular arches

Unequal crowding bilaterally in either arch

Midline discrepancies (more than 2mm)

Open bites or impinging deep bites

Question 16

Caution should be taken with patients who are more susceptible to have adverse sequaele caused by orthodontic tooth movement due to extractions, these patients include…

Answer 16

Periodontally compromised

External root resorption from previous treatment

Short blunted root morphology

Thin alveolar ridges

Obtuse nasolabial angle

Poor oral hygiene

Question 17

Which teeth should be removed in order to facilitate orthodontic tooth movement for the correction of a class 2 discrepancy?

Answer 17

A lot of things must be considered… however most of the orthodontic extractions for the correction of class 2 malocclusions involve premolars. Most commonly, maxillary and mandibular first premolars are chosen for extraction. However, it is worth considering the extraction of maxillary first premolars and mandibular second premolars so that the correction of class 2 molar relationship may be facilitated. In pts with a class 2 molar relationships and minimal mandibular crowding, sometimes only maxillary premolars are selected for extractions resulting in class 2 molar relationship but class 1 canine relationship

Question 18

Why would asymmetric extraction patterns be used?

Answer 18

Asymmetric extraction patterns involving first premolars on one side and second premolars on the other side or unilateral premolar extraction are commonly used to maximize mechanical advantage in the correction of asymmetric class 2 malocclusions

Question 19

There are many different designs of functional appliances, but they all have what two common characteristics?

Answer 19

Disarticulate the teeth

Position the mandible forward

Question 20

A protraction facemask is best used for a class 3 malocclusion with a ____ mandibular plane angle

Answer 20

Low to average

Young patients from 6-9 demonstrate a greater skeletal response, whereas adolescents show a more dental response to protraction facemask wear

Question 21

Under what circumstances should orthodontic extractions be used for the correction of a class 3 anteroposterior discrepancy?

Answer 21

Bimaxilary protrusion (in absence of generalized spacing)

Anterior open bite or anterior open bite tendency

Either growth is nearing completion or the orthodontist is confident that the treatment plan has a high probability of success

Question 22

Which teeth should be removed in order to facilitate orthodontic tooth movement for correction of a class 3 discrepancy?

Answer 22

Extraction of teeth provides space to protract maxillary anterior and posterior teeth and retract mandibular posterior and anterior teeth

Asymmetric extraction patterns can be used when correcting unilateral class 3 malocclusions

Question 23

Why should care be taken if extracting primary teeth with missing succedaneous teeth?

Answer 23

Closing the space resulting from agenesis of permanent teeth can be very difficult. Space closure by attempting to protract posterior teeth in the absence of substantial crowding can be particularly problematic