Treatment Planning

Question 1

A fundamental treatment planning concept that should be considered when every treatment plan is developed is that there is a ____ dimension of the dentition. What are the four premises?

Answer 1

Finite

Anterior limit of the dentition

Posterior limit of the dentition

Lateral limit of the dentition

Vertical limit of the dentition

Question 2

True or false… an anterior limit of the dentition exists.

Answer 2

True

Teeth must not be pushed forward off basal bone. If teeth are too far forward, all objectives of treatment are compromised.

Question 3

what can happen if you do maxillary posterior expansion?

Answer 3

It is easy to accomplish but can lead to impaction of the second molars, and, more often than not, vertical expansion

Question 4

What happens if teeth are moved too far buccally?

Answer 4

The masseter and buccinator muscles will cause relapse over the long term.

Most unstable of all lateral expansion is mandibular canine expansion.

Question 5

Treatment planning for malocclusion can be made simpler by breaking it doesn’t into components. What are the three components?

Answer 5

Face

Skeletal pattern

Teeth

Question 6

What are the prerequisites for a good face?

Answer 6

Soft tissue chin should be nicely positioned in the facial profile

A patient who has a class 2 malocclusion but who has a fairly “strong” chin can have a more balanced face after orthodontic treatment

“Weak” lips predispose a patient to compromised facial esthetics. (There should be a definite curl, which measures 3-5mm in depth to the upper lip. The lower lip form and curl must be in harmony with upper lip form and curl

Question 7

What measurements allow the clinician to quantify or measure a good face?

Answer 7

A profile line - starts at soft tissue chin, touches the most prominent lip ,and continues past the nose.

If the profile line is inside the tip of the nose, the patient generally has a pleasing facial balance.

Question 8

What is the z angle? What is the acceptable measurement?

Answer 8

It is the angle made from the profile line and the FH plane.

A pleasing face is 72 - 78 degrees

Question 9

What 3 factors affect facial balance/facial harmony?

Answer 9

Position of teeth

Skeletal pattern

Soft tissue overlay

Question 10

How do teeth affect facial balance?

Answer 10

Facial balance is affected by marked protrusion and/or crowding of the teeth.

The upper lip rests on the gingival 2/3rds of the labial surface of the maxillary incisors. The lower lip is supported by the incisal 1/3rd of the labial surface of the maxillary incisors.

Question 11

The most important prerequisite for facial balance (in regards to skeletal pattern) is…

Answer 11

Normal vertical dimension of the lower face.

The large lower anterior facial were are most often associated with a displeasing face

Studies show that AP deviations are important, but unaesthetic facial profiles that were a result of AP deviations were complexity overshadowed by long-face features; the long face feature being more unaesthetic

Question 12

The ideal face is vertically divided into equal thirds by horizontal lines that approximate the ___, the ___, the ___, and the ___.

Answer 12

Hairline

Bridge of the nose(or eyebrows)

Ala of the nose

Menton

Dividing into these thirds can help identify if facial height discrepancies are due to maxillary or mandibular issues

Question 13

The millimetric measurements of total ___ and ___ thickness are essential components in any study of facial balance. How is each measured?
how should they relate to one another?

Answer 13

Chin
Upper lip

Upper lip thickness is measured from the greatest curvature of the labial surface of the maxillary central incisors to the vermillion border of the upper lip

The total chin thickness is measured horizontally from the NB line extended to the soft tissue pogonion.

Total chin thickness should equal upper lip thickness. If total chin thickness is less than upper lip thickness, the mandibular anterior teeth must be uprigted further to facilitate a more balanced facial profile because lip retraction follows tooth retraction

Question 14

If total chin thickness is less than upper lip thickness, what should be done orthodontically?

Answer 14

Mandibular anterior teeth must be uprighted further to facilitate a more balanced facial profile because lip retraction follows tooth retraction

Question 15

What are some of the main skeletal issues that are a problem for orthodontic treatment planning?

Answer 15

Maxilla - maxillary posterior alveolar excess and an inferiorly or superiorly positioned maxilla

Mandible - posterior alveolar excess and short/long mandibular rami

Other abnormalities may include a superiorly positioned condylar fossa, obtuse cranial base angle, and/or condylar resorption

Question 16

There are several factors that influence skeletal pattern in the vertical plane, but what are the two most significant ones?

Answer 16

Condylar growth

Dentoalveolar development

Question 17

What does condylar growth have to do with the skeletal pattern, and ultimately, with treatment planing?

Answer 17

The most common direction of condylar growth is vertical with some anterior components

Pts with a pronounced short lower anterior facial height generally exhibit upward and forward condylar growth. These individuals generally have a deep overbite with a deep mentolabial sulcus and a strong over-closed apperance

In contrast, pts with a long anterior facial height have a more posterior directed growth pattern of the mandibular condyle. These backward growth rotators have increased anterior facial height, a more posture chin posture, and in extreme cases and anterior open bite

Question 18

Forward mandibular rotation occurs when vertical condylar growth __ the sum of vertical growth of the maxillary sutures and the maxillary/mandibular alveolar processes.

When alveolar process growth exceeds condylar growth, ___ Rotation occurs and the face becomes ___.

Answer 18

Exceeds

Forward

Longer

Question 19

True or false… airway obstructions due to large adenoids, tonsils, septum deviations, large conchae, or allergies are frequently observed in high-angle, long anterior facial height patients and may affect mandibular posture by allowing more freedom for posterior tooth eruption. This is due to a study in which closure of the mandibular plane angle and reduction in anterior face height was achieved after removal of adenoids and a tonsillectomy

Answer 19

True

However, recent studies have only partially clarified this study. Both normal and long-face children are likely to be predominantly nasal breathers under laboratory conditions.

In conclusion, it appears that mouth breathing may contribute to the development of orthodontic problems, but it is difficult to indict it as a primary etiologic agent

Question 20

Clinically, most orthodontists should refer mouth breathers to an ___ for an evaluation. This problem should be evaluated carefully during the diagnosis of a patient with ____

Answer 20

Otolaryngologist

Excess vertical dimension

Question 21

An ANB above ___ degrees usually indicates that orthognathic surgery could be a possible adjunct to treatment. A negative ANB value is perhaps even more indicative of horizontal facial disproportion.

Answer 21

10

Question 22

What is the normal range for ANB?

Answer 22

1-5

Question 23

The dentition is divided into three areas: ___, ___, and ___. This division is made for two reasons: simplicity in identifiying the area of space deficit or surplus and the possibility of arriving at a more accurate differential diagnosis

Answer 23

Anterior

Midarch

Posterior

Question 24

Describe the anterior space analysis

Answer 24

Difference in millimeters between space available in the mandibular arch from the distal of the central lateral canines with the MD widths of all size anterior teeth

A ceph discrepancy, or the calculation of how much space is necessary if mandibular incisor uprighting is necessary, must be added to the anterior space deficit/surplus.

Question 25

Define cephalometric discrepancy

Answer 25

Pts who have pleasing facial esthetics have a FH- mandibular incisor angle of 62-70 degrees.

FMA 21-29 FMIA should be 68
FMA 30+: FMI should be 65
FMA 20-: IMPA should not exceed original incisor inclination

A distance between existing incisal inclination and desired inclination is measured is the distance in mm that mandibular incisors must be uprighted

Question 26

Which teeth are included in the midspace arch analysis?

Answer 26

Mandibular first molars

Second premolars

First premolars

Analysis of this area can show mesially inclined first molars, rotations, spaces, or deep curve of spee, crossbite, misting teeth, habit abnormalities, blocked-out teeth, and occlusal disharmanties

Question 27

How is the midarch space analysis conducted?

Answer 27

Measure from distal of canine to distal of first molars = available midarch space

Measure MD widths of premolars and first molar.

Space available - space required.

Then, added space required to level the curve of spee. To measure curve of spee, the greatest curve depth is measured on both sides, the values are summed and divided by two

Question 28

How does one analyze the depth of curve of spee?

Answer 28

Measure the greatest depth of curve on both sides, add these values together, then divide by two.

Question 29

Regardless of age, the ___ appears to be the posterior limit of the dentition

Answer 29

Anterior border of the ramus

Question 30

How do you conduct the posterior space analysis?

Answer 30

The required space is the sum of MD widths of the mandibular second and third molars

The available space is more difficult to ascertain on the immature patient. It is:
A measurement in millimeters of the space distal to the mandibular first molar, along the occlusal plane, to the anterior border of the ramus.
an estimate of posterior arch length increase based on both age and sex

Question 31

The posterior limit of space increases ___mm per year until age 14 in girls, and age 16 in boys

Answer 31

3mm (1.5mm each side)

Question 32

The more hyperdivergent the face and skeletal pattern the [more/less] mandibular incisors need to be upright over basal bone in order to achieve facial balance. If there is any crowding at all, teeth must be extracted if a favorable facial change is desired.

Answer 32

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Question 33

The more hypodivergent the skeletal pattern and face, the [more/less] mandibular incisors need to remain in their pretreatment positions. Mandibular incisor uprighting will generally…

However, if severe crowding is present, these patients must not be treatment planned to that the mandibular teeth are proclined from their original positions. Proclination of the teeth has deleterious effects on both the face and the stability of the teeth.

Answer 33

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Harm facial esthetics