Retrusion

Question 1

Retrusion

retrusion is a ___________ arch deviation

Answer 1

sagittal dental arch deviation

Question 2

Retrusion

Retrusion definition

Answer 2

• Shortened anterior part of dental arch=>
• Backward movement of anterior teeth or lingual inclination=>
• Front teeth positioned further back than normal

Question 3

Retrusion

Prevalence of retrusion in permanent dentition

Answer 3

1.5%

Question 4

Retrusion

Dentitions retrusion affects

Answer 4

• Primary, mixed, and permanent
• Single or both jaws=>
• Biretrusion

Question 5

Retrusion

Difference between retrusion and retroalveolia

Answer 5

• Retrusion: anterior teeth move backward
• Retroalveolia: alveolar crest moves backward along w/ teeth

Question 6

Retrusion

Etiological factors of retrusion

Answer 6

I. Factors causing backward movement or lingual inclination of front teeth:
* Bad habits (e.g., thumb and object sucking, lower lip sucking)
* Muscle imbalance, particularly hypertonic orbicularis oris

II. Factors causing backward movement of anterior part of alveolar crest:
* Hypodontia in frontal segment
* Short lingual frenulum
* Microglossia or a hypotonic tongue (reduced tongue size or strength)
* Lip cicatrices (scars)
* Anterior cross-bite=>restricts normal development of maxilla

III. Heredity:
* Genetic predisposition to biretrusion

Question 7

Retrusion

Clinical features of retrusion

Answer 7

• Extraoral findings:
• Short lower third of face
• Caved-in upper lip in its central part
• S-shaped upper lip
• Thick lower lip
• Intraoral findings:
• Shortened dental arch
• Lower arch trapezoid shape
• Lingually inclined upper frontal teeth
• Possible rotation of teeth
• Retained permanent canines
• Symmetric or asymmetric retrusion involving one or both jaws (biretrusion)

Question 8

Retrusion

Types of retrusion

Answer 8

• Retrusion in its pure form: Angle Class I
• Maxillary retrusion: Associated w/ cross-bite
• Mandibular retrusion: Associated w/ overjet
• Biretrusion: Leads to severe deep bite

Question 9

Retrusion

Common disturbances associated with retrusion

Answer 9

• Function: Difficulty w/ incisal biting
• Periodontal health: Poor oral hygiene and overloading of frontal teeth
• Aesthetics: Disturbed appearance, especially when combined w/ deep bite or distal bite

Question 10

Retrusion

How retrusion diagnosed in different dentitions

Answer 10

1. Primary Dentition:
   * Cast models to evaluate dental arch shape and occlusion.
2. Mixed Dentition:
   * Cast models for dental arch shape and occlusion
   * Cephalometry
3. Permanent Dentition:
   * Clinical assessment through intraoral and extraoral examination
   * Paraclinical assessment: Biometric examination of anterior arch length (Lo and Lu)
   * Radiography: Lateral cephalometry=>
   * Angle of upper incisor (SN < 104°) and lower incisor (MP < 90°)

Question 11

Retrusion

Differential diagnosis for retrusion

Answer 11

• Maxillary retrusion (Angle Class I) vs. retrusion resulting from medialized posterior teeth
• Mandibular retrusion w/ severe lingual inclination (Angle Class I) vs. prognathia (Angle Class II1) w/ normal lingual inclination of lower anterior teeth
• Maxillary retrusion w/ severe lingual inclination (Angle Class I) vs. progenia w/ anterior cross-bite (Angle Class III) and normal lingual inclination of upper anterior teeth

Question 12

Retrusion

How retrusion prevented

Answer 12

• Eliminating etiological factors such as bad habits
• Restoring myofunctional balance (muscle coordination around mouth)

Note: Self-correction is possible in primary dentition.

Question 13

Retrusion

Aim of treatment for retrusion

Answer 13

Vestibularly incline upper and/or lower anterior teeth

Question 14

Retrusion

key elements of treatment plan for retrusion

Answer 14

• Create space for anterior teeth using=>
  Expansion, Distalization, Stripping, or Extraction
• Release occlusion (disarticulate the bite)
• Protrusion of frontal teeth
• Correction of dental arch shape
• Stimulation of apical base if necessary

Question 15

Retrusion

How retrusion treated in primary dentition

Answer 15

• Elimination of bad habits
• Appliances=>
• Lingual plate w/ screw
• Preventive appliances against bad habits

Treatment for maxillary retrusion, especially if it stops the development of the lower jaw or results in cross-bite/progenia

Question 16

Retrusion

Best time for retrusion treatment in primary dentition

Answer 16

When stable primary incisors present

Question 17

Retrusion

How retrusion treated in mixed dentition

Answer 17

• Eliminate bad habits
• Protrude frontal teeth
• Optimal time for treatment between 8-9 years (after eruption of permanent incisors but before resorption of posterior teeth roots)

Question 18

Retrusion

Appliances used in mixed dentition for retrusion treatment

Answer 18

• Lingual plate w/ screw/protrusive spring=>
• Provides occlusal coverage to disarticulate bite and reinforce anchorage
• Functional appliances=> Klammt II and Fränkel II

Question 19

Retrusion

Retrusion Treatment approach in permanent dentition

Answer 19

• Vestibular inclination of frontal teeth
• Release bite if necessary
• Gain space: 1 mm of incisor protrusion creates 2.5 mm of space in posterior segment

Question 20

Retrusion

Side effects of treating retrusion in permanent dentition

Answer 20

• Protrusion decreases overbite
• Protrusion of lower frontal teeth caries risk of root recession=>
• Especially w/ rapid protrusion or apical base deficiency

Question 21

Retrusion

Appliances used in permanent dentition for retrusion treatment

Answer 21

• Edgewise technique: Protrusion occurs alongside reshaping dental arch
• Lingual plate w/ protrusive screw or springs (rarely used, mostly for opening bite)

Question 22

Retrusion

Factors that affect retention after retrusion treatment

Answer 22

• Periodontal health
• Presence of bad habits
• Myofunctional balance

Question 23

Retrusion…….

Sagittal dental arch deviations in the lateral segment

Answer 23

• Tooth-jaw deformation affecting single jaw=>
• Posterior teeth move in anterior (medialized) or posterior (distalized) direction

Question 24

Retrusion…….

Types of sagittal dental arch deviations in the lateral segment

Answer 24

• Mesioposition of posterior teeth
• Distoposition of posterior teeth

Question 25

# Retrusion...... Dentitions and jaws affected by sagittal dental arch deviations in lateral segment

Answer 25

* **Primary dentition**: It can occur but is rare. * **Mixed and permanent dentition**: More commonly affected * **Maxilla, mandible, or both jaws**

Question 26

# Retrusion..... Etiological factors of sagittal dental arch deviations in the lateral segment

Answer 26

* **Early extraction of primary teeth=>** * Simultaneous medialization of both primary teeth and germs of permanent teeth * **Hypodontia or retained permanent tooth** * **Early loss of a permanent tooth** * **Medialization of posterior teeth caused by eruption of wisdom teeth**

Question 27

# Retrusion...... Clinical features of sagittal dental arch deviations in the lateral segment

Answer 27

1. **Intraoral**: * **Dental arch shape altered** * **Teeth position**=> * Inclined, translated, or rotated * May be positioned outside dental arch—vestibularly in maxilla or lingually in mandible * **Inclination of molars**=> * In mandible, molars tend incline; in maxilla, become upright * **Jaw involvement**=> * Single jaw or both jaws 2. **Occlusion deviations** * **Sagittal deviations=>**distal or medial occlusion, depending on affected jaws * **Transversal deviations=>**cross-bite or cusp-to-cusp bite

Question 28

# Retrusion...... How sagittal dental arch deviation in lateral segment diagnosed in different dentitions

Answer 28

1. **Primary Dentition**=> * Rarely affected, hence diagnosis uncommon 2. **Mixed Dentition**=> * Cast model assessment to evaluate dental arch shape and occlusion * Radiography=>OPG, Cürol's method or Cephaplometry to assess angles α and β 3. **Permanent Dentition**=> * Clinical assessment: Intraoral examination. * Paraclinical assessment: Biometric examination of Schmuth's Raphe-Papilla Tangent (RPT), drawing perpendiculars to sagittal midline * Radiography: OPG (Cürol's method) and cephalometry to assess angles α and β.

Question 29

# Retrusion...... Schmuth's Raphe-Papilla Tangent (RPT) method

Answer 29

* Determines **mesio-distal movement of posterior teeth**=> * Drawing **perpendicular lines** from identical points on corresponding teeth on left and right sides to **midsagittal line** * If lines do not match, tooth that is more **mesially placed** considered to be **sagittally displaced**

Question 30

# Retrusion..... Significance of angles α and β in diagnosis

Answer 30

* Increased Angle α: Indicates mesially inclined **upper molars** * Decreased Angle β: Indicates mesially inclined **lower molars**

Question 31

# Retrusion..... Assement of medial inclinication of the roots of upper first molars

Answer 31

* angle = 100° - normal root inclination of tooth 16 * angle < 100° - medial root inclination of tooth 16

Question 32

# Retrusion..... Differential diagnosis for sagittal dental arch deviations in the lateral segment

Answer 32

* Involves distinguishing between: 1. Medialized posterior teeth and retrusion of same jaw 2. In cases of anterior crowding: * Compression * Retrusion * Medialized posterior teeth

Question 33

# Retrusion...... How treatment approached in mixed dentition for sagittal dental arch deviations in the lateral segment

Answer 33

* **Distalization of medialized teeth=>** * Should start in **mixed dentition and continue until permanent dentition established** * Ideal age is **9-11 years**

Question 34

# Retrusion.... Appliances used for treatment of sagittal dental arch deviations in the lateral segment(mixed dentition)

Answer 34

* Lingual plate with a distalizing screw * Extraoral appliances (EOA) * Pendulum appliance

Question 35

# Retrusion.... When treatment of sagittal dental arch deviations in the lateral segment begun and appliances used (permanent dentition)

Answer 35

* Before eruption of teeth **17 and 27** * **Lingual plate w/ distalizing screw** * **Extraoral appliances (EOA)** * **Pendulum appliance** * **Edgewise technique**

Question 36

# Retrusion.... Challenges in distalizing lower permanent molar

Answer 36

Challenge due to anatomical positioning and resistance to movement

Question 37

# Retrusion.... Appliance used specifically for distalizing lower permanent molars

Answer 37

Lipbumper

Question 38

#Retrusion Factors causing backward movement or lingual inclination of front teeth

Answer 38

* Bad habits (e.g., thumb and object sucking, lower lip sucking) * Muscle imbalance, particularly hypertonic orbicularis oris ## Footnote These factors can contribute to dental malocclusions and affect oral health.

Question 39

#Retrusion Factors causing backward movement of anterior part of the alveolar crest

Answer 39

* Hypodontia in frontal segment * Short lingual frenulum * Microglossia or a hypotonic tongue * Lip cicatrices (scars) * Anterior cross-bite ## Footnote These conditions can hinder proper dental alignment and development of the maxilla.

Question 40

#Retrusion Fill in the blank: Factors causing backward movement or lingual inclination of front teeth include bad habits and _______.

Answer 40

muscle imbalance ## Footnote Muscle imbalances can lead to improper positioning of teeth.

Question 41

#Retrusion True or False: A short lingual frenulum can contribute to retrusion.

Answer 41

True ## Footnote A short frenulum can restrict tongue movement, affecting dental alignment.

Question 42

#Retrusion What condition is associated with reduced tongue size or strength?

Answer 42

Microglossia ## Footnote This condition can impact oral function and tooth positioning.

Question 43

#Retrusion Extraoral findings of retrusion

Answer 43

* Short lower third of face * Caved-in upper lip in its central part * S-shaped upper lip * Thick lower lip ## Footnote Extraoral findings refer to observable characteristics of the face outside of the mouth.

Question 44

#Retrusion Intraoral findings of retrusion

Answer 44

* Shortened dental arch * Lower arch trapezoid shape * Lingually inclined upper frontal teeth * Possible rotation of teeth * Retained permanent canines * Symmetric or asymmetric retrusion involving one or both jaws (biretrusion) ## Footnote Intraoral findings refer to characteristics observed within the mouth.

Question 45

#Retrusion Fill in the blank: A characteristic of retrusion is a _______ lower third of face.

Answer 45

short

Question 46

#Retrusion True or False: An S-shaped upper lip is a feature of retrusion.

Answer 46

True

Question 47

#Retrusion What shape does the lower arch take in retrusion?

Answer 47

trapezoid

Question 48

#Retrusion Fill in the blank: Lingually inclined upper frontal teeth are an intraoral finding of _______.

Answer 48

retrusion

Question 49

#Retrusion What can be a possible dental issue associated with retrusion?

Answer 49

Retained permanent canines ## Footnote Retained canines may indicate issues with tooth eruption or alignment.

Question 50

#Retrusion What does biretrusion refer to?

Answer 50

Symmetric or asymmetric retrusion involving one or both jaws

Question 51

#Retrusion Intraoral clinical features of Sagittal dental arch deviations of lateral segment

Answer 51

* **Dental arch shape altered** * **Teeth position**=> * Inclined, translated, or rotated * May be positioned outside dental arch—vestibularly in maxilla or lingually in mandible * **Inclination of molars**=> * In mandible, molars tend incline; in maxilla, become upright * **Jaw involvement**=> * Single jaw or both jaws

Question 52

#Retrusion Occlusal clinical features of Sagittal dental arch deviations of lateral segment

Answer 52

* **Sagittal deviations=>**distal or medial occlusion, depending on affected jaws * **Transversal deviations=>**cross-bite or cusp-to-cusp bite

Question 53

#Retrusion What does Schmuth’s raphe papilla tangent method (RPT) determine?

Answer 53

Mesio-distal movement of posterior teeth ## Footnote RPT involves analyzing the position of teeth in relation to the midsagittal line.

Question 54

#Retrusion How does the RPT method analyze tooth position?

Answer 54

By drawing perpendicular lines from identical points on corresponding teeth on left and right sides to the midsagittal line ## Footnote This technique helps in visualizing the alignment of teeth.

Question 55

#Retrusion If the perpendicular lines do not match in the RPT method

Answer 55

The tooth that is more mesially placed considered sagittally displaced ## Footnote This assessment is crucial for understanding dental alignment.