Orthodontics

Expansion

• Types of expansion appliances

• Rapid maxillary expansion [RME]
  • Should be initiated prior to ossification of the mid-palatal suture
  • Time of ossification of mid-palatal suture
    • 16 years – in girls
    • 18 years – in boys
• Contraindication of RME
  • Single tooth crossbites
  • In adults with severe anteroposterior skeletal discrepancies
  • Vertical growers
  • Periodontally weak condition
• Schedule of activation of expansion screw
  • For patients upto 15 years – 90° rotation in morning and evening
  • For patients over 15 years – 45° rotation 4 times a day
• Quad helix
  • Uses:
    • Expand a narrow arch
    • Rotation of molars
    • Brings
      • Orthopaedic movement in children
      • Orthodontic movement in adults

Expansion Long Essays

Question 1. Explain slow and rapid expansion, their indications, contraindications, and appliances used.
Answer.

Read And Learn More: Orthodontics Short And Long Essay Question And Answers 

Effects Of Rapid Maxillary Expansion:

• Open mid-palatal suture:
  • By compresses PDL
  • Bends buccal alveolar process and slowly opens the suture
• Triangular opening:
  • Maximum opening at incisor region
  • Reduces over posterior part of palate

• • Maximum opening towards oral cavity
  • Less opening towards nasal aspect
• Midline diastema
• Buccal tipping of maxillary posteriors

• Downward and backward mandibular rotation
• Increase in mandibular plane angle
• Displacement adjacent cranial bones
• Increase in intra-nasal space
• Reduction in airway resistance

Expansion Short Essays

Question 1. Expansion screws.
Answer.

• A typical expansion screw consists of an oblong body with two halves, each half consisting of threaded inner side that receives one end of a double-ended screw
• The screw has a central basing with four holes, which receive a key used to turn the screw
• The turning of screw to 90 degrees brings about linear movement of 0.18mm
• Various types of expansion used in removable and fixed appliances are
  • Jackscrew
  • Coffin springs
  • Qual helix
  • Isacson
  • Hyrax
  • Derischweiler
• Activation schedules

According to Timms:

• In patient upto 15 years of age – 90 degrees rotation in the morning and evening
• In patient over 15 years old – 45 degrees activation 4 times a day

According to Zimring and Isacson:

• In growing individuals
  • Two turns each day for 4-5 days and later one turn per day till the desired expansion is achieved
• In non-growing adults
  • Two turns each day for first 2 days and later one turn per day for next 5-7 days and one turn every alternate day till the desired expansion is achieved

Question 2. Quad Helix Appliance.
Answer.

Example of slow maxillary expansion appliance

Introduced by Walter coffin

• Wired used: 0.038 inch
  • Parts
• Bands: Over first molar
• Helices: 2 anteriors helices
  • 2 posterior helices
• Bridge: Anterior bridge – Connencts anterior helices
• Palatal bridge: Connects anterior and posterior helices
• Outer arms: Free ends adjacent to posterior helices
  • Soldered on lingual aspect of molar bands
• Uses: Expansion of narrow arch
  • Rotation of molars
• Skeletal expansion: During mixed dentition periods
• Activation: Pre-stretching of molar bands before cemenstation.

Question 3. Rapid v/s slow expansion.
Answer.

Expansion Short Questions And Answers

Question 1. Hyrax Appliance.
Answer.

Tooth bone fixed appliances used for rapid maxillary expansion

Hyrax – Hygienic rapid expander

Designs Of Hyrax Appliance:

• Wire used – Heavy guage wire
• Extensions of screw wire are adapted over palatal contour and soldered to molar bonds

Question 2. Coffin Spring.
Answer.

• Removable slow expansion appliance by Walter Coffin
• Wire used: 1.25 mm thick
• Design: Omega shaped wire – Over mid-palatal region
• Free ends of wire: Embedded in acrylic
• Activation: Pulling two sides apart
• Use: Dento-alveolar expansion in adults
• Skeletal expansion in younger patients

Question 3. Expansion Appliance.
Answer.

• Appliance for RME
  • Removable – Split acrylic plate
  • Fixed
• Tooth and tissue borne
  • Derichsweiler type
  • Hass type
• Tooth borne
  • Issacson type
  • Hyrax type
• Appliances for Slow Expansion
  • Jack screw
  • Coffin spring
  • Quad helix
  • Fixed appliance

Question 4. Slow Expansion Appliance.
Answer.

• Jack screw:
  • It is incorporated in the appliances
  • Have more spread out activation schedule
  • Have smaller pitch
• Coffin spring:
  • Removable slow expansion appliance by Walter Coffin
  • Wire used – 1.25 mm thick
  • Design – Omega shaped wire – Ove mid-palatal region
  • Free ends of wire – Embedded in acrylic
  • Activation – Pulling two sides apart
  • Use – Dento-alveolar expansion in adults
  • Skeletal expansion in younger patients
• Quad helix:
  • Introduced by Walter coffin
  • Wire used – 0.038 inch
    • Parts
• Bands – Anterior bridge – Connects anterior helices
• Palatal bridge – Connects anterior and posterior helices
• Outer arms – Free ends adjacent to posterior helices
  • Soldered on lingual aspect of molar bands
• Uses: Expansion of narrow arch
  • Rotation of molars

Question 5. Types of Expansion Screws.
Answer.

• 3D screws
• Split midline screw
• Jack screw

Expansion Viva Voce

• Coffin spring and quad helix are used for palatal expansion
• Rapid palatal expansion should be carried out prior to ossification of midpalatal suture
• In rapid expansion two turns daily of 0.5mm is done
• In slow expansion the rate is 0.5 mm per week
• In rapid expansion, the ratio of skeletal to dental expansions is 4:1
• In slow expansion, the ratio of skeletal to dental expansions is 1:1
• In rapid expansion, force generated – 2-4 pounds
• In slow expansion, force generated – 10-20 pounds
• Treatment completed in rapid expansion – 1-2 weeks
• Treatment completed in slow expansion – 2-5 months

Genetics In Orthodontics Short Essays

Question 1. Genetic malocclusions.
Answer.

• Disturbance in tooth size: Micrognathia, macrognathia
• Disturbance in tooth number:
  • Hypodontia
  • Anodontia
  • Oligodontia etc.
• Disturbance in alignment of teeth:
  • Abnormal overjet and overbite
  • Open bite
• Effecting other structures:
  • Cleft lip and palate
    • High arched palate
  • Bimaxillary protrusion
  • Bimaxillary atresia
• Syndromes associated with it:
  • Down’s syndrome
  • Gardner’s syndrome
  • Marfan’s syndrome
  • Cleido-cranial dysplasia
  • Mandibulo facial dysostosis
• General conditions:
  • Cherubism
  • Osteogenesis imperfecta
  • Retarded tooth eruption

Read And Learn More: Orthodontics Short And Long Essay Question And Answers 

Question 2. Importance of Genetics in Orthodontics.
Answer.

• First recognized by Frederick G. Kussel in 1836
• He found that some of the malocclusions are transmitted from one generation to other
• The cause of relapse also has a hereditary influence
• Occlusal malrelations, jaw positioning and pressure habits are all results of genetic alteration
• Some of examples of genetic malocclusions are
  • Disturbance in tooth size: Micrognathia, macrognathia
  • Disturbance in tooth number:
    • Hypodontia
    • Anodontia
    • Oligodontia etc.
  • Disturbance in alignment of teeth:
    • Abnormal overjet and overbite
    • Open bite
  • Effecting other structures:
    • Cleft lip and palate
  • High arched palate
    • Bimaxillary protrusion
    • Bimaxillary atresia
  • Syndromes associated with it:
    • Down’s syndrome
    • Gardner’s syndrome
    • Marfan’s syndrome
    • Cleidocranial dysplasia
    • Mandibulo facial dysostosis
  • General conditions:
    • Cherubism
    • Osteogenesis imperfecta
    • Retarded tooth eruption

Question 3. Syndromes and malocclusions.
Answer.

Genetics In Orthodontics Short Questions And Answers

Question 1. Genetic Counselling.
Answer.

It is communication between the counsellor and the patients having hereditary disease which enables the parents to decide to continue pregnancy/to abort

• It is carried out only between counsellor and parents’ confidential
• Decisions must be on the patient, the counsellor must not force the patient
• Counsellor must be confirmed about the diagnosis and severity of the disease
• Counsellor must reveal all the possible sequelae of the hereditary diseases

Question 2. Twin Studies
Answer.

It involves the study of human things

Human twins are of 2 types

Introduction To Orthodontics Definition

Orthodontics:

Orthodontics includes the study of the growth and development of the jaws and face particularly and the body generally as influencing the position of the teeth, the study of action and reaction of internal and external influences on the arrested and perverted development.

Introduction To Orthodontics Important Notes

Jackson’s Triad:

• Functional Efficiency
  • As malocclusion affects normal functioning of stomatognathic system
  • Orthodontic treatment restores it
• Structural balance
  • Three tissues constituents oro-facial region i.e., dentoalveolar, skeletal and soft tissues
  • Orthodontic treatment obtains a balance among them
• Esthetic harmony
  • Malocclusion effects the facial appearance of the individual
  • This effects the psychology of the person
  • Thus orthodontic treatment prevents this by improving the facial appearance

Read And Learn More: Orthodontics Short And Long Essay Question And Answers 

Introduction To Orthodontics Short Essays

Question 1. Aims of orthodontics.
Answer.

• Summarized by Jackson
• Also termed as Jackson’s triad

Aims Of Orthodontics:

• Functional Efficiency:
  • As malocclusion affects normal functioning of stomatognathic system
  • Orthodontic treatment restores it
• Structural Balance:
  • Three tissues constituents oro-facial region i.e., dentoalveolar, skeletal and soft tissues
  • Orthodontic treatment obtains a balance among them
• Esthetic harmony:
  • Malocclusion effects the facial appearance of the individual
  • This effects the psychology of the person
  • Thus orthodontic treatment prevents this by improving the facial appearance

Introduction To Orthodontics Short Questions And Answers

Question 1. Define orthodontics.
Answer.

By British Society

Orthodontics includes the study of the growth and development of the jaws and face particularly and the body generally as influencing the position of the teeth, and the study of action and reaction of internal and external influences on the arrested and prevented development.

Question 2. Sequele of Malocclusion.
Answer.

• Poor facial appearance
• Risk of caries
• Predisposition to periodontal diseases
• Psychological disturbances
• Risk of trauma
• Abnormalities of function
• TMJ problems

Question 3. Jackson’s triad/Aims of orthodontics.
Answer.

• Functional efficiency
• Structural balance
• Esthetic harmony

Question 4. Need for orthodontic treatment.
Answer.

• For esthetic problems
• For restoration of functions
• For the balance of oro-facial structure
• To prevent periodontal problems

Question 5. Angle’s contribution to orthodontics.
Answer.

• Father of Modern Orthodontics
• Classification of malocclusion
• Introduction of orthodontics as a separate branch
• Started a school of orthodontics ar St.Louis, New London
• Advocated arch expansion

Introduction To Orthodontics Viva Voce

• Aesthetic harmony is the most common reason for seeking orthodontic care
• Edward Hartely Angle is the father of modern orthodontics
• Pierre Fauchard is the founder of modern dentistry
• Edward H Angle promoted orthodontics as a specialty
• William E Magil was the first to band the teeth for active tooth movement
• Hippocrates is the pioneer of medical science
• Le Felon first coined the word orthodontics

Orthodontic Appliances General Concepts Short Questions

Question 1. Advantages and disadvantages of removable appliances.
Answer.

Removable Appliances Advantages:

• Oral hygiene maintenance
• Useful in tipping movement
• Less chair time
• Convenient to operators to handle more patient
• Fewer forces required
• Not technique sensitive
• Easy to fabricate
• Relatively cheaper
• Damaged appliances can be replaced

Removable Appliances Disadvantages:

• Poor patient cooperation
• Capable of only tipping movement
• Prolonged duration of treatment
• Difficult to treat multiple rotations
• Difficult to close residual space created due to extraction
• Risk of damaging and misplacing appliances by patient
• Cannot be used to treat severe cases of Class 2 and Class 3 malocclusions with unfavorable growth pattern

Question 2. Ideal requisites of Orthodontic appliances.
Answer.

• Biologic requirements:
  • Able to result in desired tooth movement
  • Should not create any damage to oral structures
  • Should not interfere with growth
  • Should not interfere with oral functions
  • Should not create unwanted tooth movement
  • Biocompatible
  • Should not disintegrate
• Mechanical requirement
  • Simple to fabricate
  • Not bulky
  • Strong to withstand forces
  • Able to apply forces to tooth
  • Universal applicable
• Hygienic
  • Should be self-cleansing
• Esthetic
  • Esthetically acceptable

Orthodontic Appliances General Concepts Short Questions And Answers

Question 1. Disadvantages of Fixed Appliances.
Answer.

• Difficult to maintain oral hygiene
• More time consuming
• More chair time required
• Technique sensitive
• May apply misdirected forces
• Frequent visits required
• Expensive

Question 2. Advantages of Fixed Appliances.
Answer.

• Cooperation of the patient is achieved
• Various tooth movements are possible
• Tooth movement of multiple teeth is possible simultaneously
• Good occlusion is achieved
• More precise tooth movements are possible

Read And Learn More: Orthodontics Short And Long Essay Question And Answers 

• Can be used in complicated malocclusions
• Better anchorage is obtained
• Management of appliances possible
• Convenient for the operator as no need for timely wear of the appliance
• Less time for treatment required

Question 3. Ideal requirements of removable appliances.
Answer.

• Biologic requirements:
  • Able to result in desired tooth movement
  • Should not create any damage to oral structures
  • Should not interfere with growth
  • Should not interfere with oral functions
  • Should not create unwanted tooth treatment
  • Biocompatible
  • Should not disintegrate
• Mechanical requirement:
  • Simple to fabricate
  • Not bulky
  • Strong to withstand forces
  • Able to apply forces to tooth
  • Universal applicable
• Hygienic:
  • Should be self-cleansing
• Esthetic:
  • Esthetically acceptable

Question 4. Advantages of removable appliances.
Answer.

• Oral hygiene maintenance
• Useful in tipping movement
• Less chair time
• Convenient for the operator to handle movement
• Fewer forces required
• Not technique sensitive
• Easy to fabricate
• Relatively cheaper
• Damaged appliances can be replaced

Orthodontic Diagnosis Important Notes

• Cephalic index
  • The shape of the head can be evaluated based on a cephalic index of the head formulated by Martin and Saller
  • Cephalic index = posterior facial height / anterior facial height

• Facial form

• Types of lips

• Facial divergence

• Nasolabial angle
  • It is an angle formed between the lower border nose and a line connecting the nose and upper lips
  • The normal value is 110 degrees
  • Reduced in patients with proclined maxillary anterior or prognathic maxillary
  • Increased in patients with retrognathic maxilla or reclined maxillary anterior
• Path of closure of mandible
  • Backward in class 2 division 2
  • Forward in pseudo-class 3
  • Lateral in unilateral crossbites

Orthodontic Diagnosis Long Essays

Question 1. Discuss in detail the various diagnostic aids used in orthodontics.
Answer.

Diagnosis:

• It involves the collection of pertinent data in a systemic manner to help identify the nature and cause of the problem

Read And Learn More: Orthodontics Short And Long Essay Question And Answers

Diagnosis Aids:

• Comprehensive orthodontic diagnosis is established by the use of certain clinical implements called diagnostic aids

Types Of Diagnosis Aids:

• Essential Diagnostic aids
  • Case history
  • Clinical examination
  • Study models
  • Certain radiographs
  • Facial radiographs
• Supplemental diagnostic aids
  • Specialized radiographs
  • Electromyographs
  • Hand wrist radiographs
  • Endocrine tests
  • Estimation of basal metabolic rates
  • Diagnostic set-up
  • Occlusograms
• Essential Diagnostic aids:
  • Aids that are important for all cases
  • Involves

Case History involves:

• Personal details:
  • Name – For maintaining a record
    • Addressing patient
    • For communication
  • Age – for treatment planning
    • Growth period – Myofunctional appliances
    • After cessation of growth-surgical treatment
  • Sex – growth spurts differ in both sex
  • Address – for further correspondence

• Chief complaints: Help to identify the expectations of the patient
• Medical history: epilepsy, diabetes, and blood dyscrasias complicate the treatment
• Dental history: to know the attitude of the patient toward treatment
• Pre-natal history: for knowing the condition of the mother during pregnancy
  • Forcep delivery leads to cross-bite
• Post-natal history: to know milestones of development
• Family history: some occlusions like clefts are hereditary

Clinical Examination:

General:

• Height
• Weight
• Gait
• Posture
• Body build

Extra-Oral:

• Head shape
• Facial form
• Facial Profile
• Facial symmetry
• Facial divergence
• Anteroposterior relationship
• Facial proportions
• Lips
• Nose
• Nasolabial angle

Intra-Oral:

• Tongue
• Palate
• Gingiva
• Frenal attachment
• Tonsils
• Adenoids
• Dentition

Functional Examination:

• Postural rest position
• Path of closure
• TMJ
• Swallowing
• Speech
• Respiration

Study models:

• Provide a 3D view of the situation

Uses Of Orthodontics:

• Studies occlusion from all aspects
• Enables accurate measurement
• Treatment planning
• Assess the severity of malocclusion
• Motivate the patient
• For mock surgery
• For transparency records

Steps in Fabrication:

• Impression making – By alginate
• Disinfecting it – By Biocide
• Casting the impression – By model stone
• Basing and trimming the cast
• Finishing and Polishing – By fine-grained sandpaper

Radiographs:

• Commonly used radiographs are

Cephalometric: For skeletal malocclusion

• IOPA – to know the bone condition
• Occlusion radiograph – for arch length

Facial Photographs:

• To compare pre and post-treatment conditions

Supplemental Diagnostic Aids

• Require only in specialized cases
• Includes – electromyography
  • Hand wrist radiograph
  • Endocrine test
  • Estimation of BMR (Basal Metabolic Rate)
  • Diagnostic set up
  • Occlusograms
  • MRI, CT scan

Question 2. What are various diagnostic aids in orthodontics? Write in detail about clinical examination and case history records.
Answer.

Diagnostic Aids:

Essential Diagnostic aids:

• Case history
• Clinical examination
• Study models
• Certain radiographs
• Facial photographs

Supplemental diagnostic aids:

• Specialized radiographs
• Electromyographs
• Hand wrist radiographs
• Endocrine tests
• Estimation of basal metabolic rates
• Diagnostic set-up
• Occlusograms

Case History involves:

• Personal details:
  • Name – For maintaining a record
    • Addressing patient
    • For communication
  • Age – for treatment planning
    • Growth period – Myofunctional appliances
    • After cessation of growth-surgical treatment
  • Sex – growth spurts differ in both sex
  • Address – for further correspondence
• Chief complaints: Help to identify the expectations of the patient
• Medical history: Epilepsy, diabetes, and blood dyscrasias complicate the treatment
• Dental history: To know the attitude of the patient toward treatment
• Pre-natal history: For knowing the condition of the mother during pregnancy
  • Forcep delivery leads to cross-bite
• Post-natal history: To know milestones of development
• Family history: Some occlusions like clefts are hereditary

Clinical Examination:

General:

• Height
  • Provide information on physical growth and maturation of the patient that may influence oro-facial development
• Weight
  • Provide information on the physical growth and maturation of the patient that may influence oro-facial development
• Gait
  • Gait abnormality is associated with neuromuscular problems
• Posture
  • Abnormal posture can predispose to malocclusion
• Body build
  • Types:
    • Aesthetic
      • Thin physique
      • Narrow dental arches
    • Plethoric
      • Obese persons
      • Large, square dental arches
    • Athletic
      • Normal built
      • Normal-size dental arches

Extra-Oral:

• Head shape
  • Types:
    • Mesocephalic
      • The average shape of the head
      • Normal dental arches
    • Dolichocephalic
      • Long and narrow head
      • Narrow dental arches
    • Brachycephalic
      • Broad and short head
      • Broad dental arches

Facial form:

• Types:
  • Mesoprosopic
    • Average face from
  • Euryprosopic
    • Broad and short facial form
  • Leptoprosopic
    • Long and narrow facial form

Facial profile:

• Examined by viewing the patient from the side
• Diagnoses gross deviations in the maxillo-mandibular relationship

Types:

• Straight
• Convex
• Concave

Facial symmetry:

• Determines disproportions of the face in transverse and vertical planes

Facial divergence:

• It is an anterior or posterior inclination of the lower face relative to the forehead

Types Of Facial Divergence:

• Anterior divergence
• Posterior divergence
• Straight or orthognathic
• Anteroposterior relationship
  • This can be assessed by the following
• Seat the patient in an upright position
• Ask to occlude gently
• Place index and middle finger at soft tissue points A and B respectively
• In class 1 hand is at an even level
• In class 2 Index finger is anterior to the middle finger
• In class 3 Middle finger is ahead of the forefinger

Facial proportions:

• The face is divided into three equal thirds by four horizontal planes
• At the level of hairline
• Supraorbital ridge
• The base of the nose
• The inferior border of the chin

Lips:

• Types:
  • Competent lips
  • Incompetent lips
  • Potentially incompetent lips
  • Everted lips

Note:

• It contributes to the esthetics of the face

Nasolabial angle:

• It is the angle formed between the lower border of the nose and the line connecting the intersection of the nose and the upper lip
• It is normally 110 degrees

Intra-Oral:

Tongue:

• Abnormalities in the tongue disturb muscle balance and equilibrium leading to malocclusion

Palate:

• Examined for
  • Palatal depth
  • Presence of swelling
  • Mucosal ulceration
  • Presence of clefts
  • Third rugae

Gingiva:

• Examined for
  • Inflammation
  • Recession
  • Mucogingival lesions

Frenal attachment:

• Abnormal labial frenum leads to midline diastema
• Ankyloglossia leads to the narrowing of the maxillary arch

Tonsils:

• Abnormal inflamed tonsils cause alteration in tongue and jaw posture

Adenoids:

Dentition:

• Assess the following
  • Number of teeth present
  • Number of teeth missing
  • Status of teeth-erupted or unerupted
  • Presence of caries, restorations, or malformed
  • Assess occlusion
  • Assess overjet and overbite
  • Assess individual tooth irregularities like rotations, intrusion, and extrusions
  • Assess transverse relationship
  • Examine the upper and lower arch separately

Question 3. Exumerate essential diagnostic aids. Describe study models in detail.
Answer.

Essential Diagnostic Aids:

• Case history
• Clinical examination
• Study models
• Certain radiographs
• Facial photographs

Study Models:

Uses Of Diagnostic Aids:

• Studies occlusion from all aspects
• Enables accurate measurement
• Treatment planning
• Assess the severity of malocclusion
• Motivate the patient
• For mock surgery
• For transparency records

Requirements Of Diagnostic Aids:

• Should accurately reproduce oral structures
• Should be pleasing to the eye
• Should accurately reproduce occlusion
• Should have a clean, smooth surface
• Should reproduce as much of the alveolar process as possible

Parts Of Diagnostic Aids:

• Anatomic portion
• Artistic portion

Steps:

• Impression making

Disinfecting the impression

• Casting the impression – Using orthodontic stone/model stone
• Basing and trimming of cast

• Trimming
  • Step 1: Trimming of mandibular base
  • Step 2: The back of the mandibular model is made perpendicular to the midline
  • Step 3: Both casts should occlude
  • Step 4: Backs of both casts are made right-angled to base
  • Step 5: Buccal cuts are made on mandibular cast
  • Step 6: Anterior segments made on lower cast
  • Step 7: Posterior cuts on the lower cast
  • Step 8: Buccal cuts made on the upper cast
  • Step 9: Anterior cuts on the upper cast
  • Step 10: Posterior cuts on the upper cast

• Finishing and polishing – Done using fine-grained sandpaper

Orthodontic Diagnosis Short Essays

Question 1. Intra-oral X-rays in Orthodontics
Answer.

Types Of Intra-Oral X-rays:

Intra-Oral Periapical Radiograph:

• Techniques:
  • Paralleling technique
  • Bisecting angle technique
• Uses:
  • View the presence/absence of teeth
  • Supernumerary teeth
  • Root formation
  • Periapical pathology
  • PDL space
  • The contour of alveolar bone – to assess the abnormality
  • Unerupted teeth – for tooth morphology
• Disadvantages:
• Not convenient for the entire dentition
• Gag reflex
• Uncomfortable for children

Bitewing:

• Uses:
  • To assess the height and contour of bone
  • To evaluate periodontal changes
  • To assess interproximal calculus

Occlusal:

• Uses:
  • For impacted/unerupted teeth
  • For supernumerary teeth
  • For foreign bodies
  • To view the effects of the arch expansion procedure

Question 2. Inter-incisal angle.
Answer.

It is the angle formed between the long axis of the upper and lower incisors

• Value – 135.4°
• Range – 130 – 150.5°

Significance Of Inter-incisal Angle:

• Increased in Class 2, Division 2
• Decreased – Class 1 bimaxillary protrusion
  • Class 2 Division 1

Question 3. Occlusal X-ray.
Answer.

Advantages Of Occlusal X-ray:

• Views a large segment of the dental arch
• For viewing palate and floor of mouth
• Useful in trismus

Uses Of Occlusal X-ray:

• Locate impacted teeth
• Locate fracture
• Locate supernumerary teeth
• Locate foreign bodies
• Locate effects of arch expansion procedures
• Assess the arch length
• Assess any pathology of jaws

Question 4. Overjet and Overbite.
Answer.

Overjet: It is the horizontal overlapping of maxillary and mandibular anterior

Value: 1.5 – 2mm

Significance Of Overjet: Increases in open bite cases

• Increases in anterior proclination

Overbite: It is the vertical overlapping of maxillary and mandibular anterior

Value: 1.5 – 2mm

Significance Of Overbit: Decrease – Deep bite

Increase: Open bite

Orthodontic Diagnosis Short Questions And Answers

Question 1. Facial Divergence.
Answer.

It is defined as an anterior/posterior inclination of the lower face relative to the forehead

Types Of Facial Divergence:

• Anterior divergent: A line between the forehead and chin inclines anteriorly
• Posterior divergent: A line between forehead and chin inclines posteriorly
• Straight/Orthognathic: A line between the forehead and chin is straight or perpendicular to the floor.

Question 2. Uses of Panoramic Radiograph./Orthopentogram
Answer.

• Assessing dental development
  • Studying root resorption/root formation
  • For Ankylosis
  • Impacted teeth
  • Path of eruption
  • Diagnose pathology
  • Status of eruption
  • Unerupted teeth

Question 3. Bite Wing Radiographs.
Answer.

Records coronal part of upper and lower dentition together

Uses Of Bite Wing Radiographs:

• For proximal caries
• For interdental bone contour
• For secondary caries
• Detect overhanging restoration
• Detect periodontal changes
• Detect interproximal calculus

Question 4. Electromyography.
Answer.

Used for recording the electrical activity of muscles

Types Of Electrodes Used:

• Surface electrode – Plated superficially
• Needle electrode – Placed deeply

Useful In:

• In severe Class 2 division 1 malocclusion
• Abnormal buccinator activity
• Overclosure of jaws
• Cerebral palsy
• After orthodontic therapy

Question 5. Clinical Evaluation of Facial Profile.
Answer.

The patient is viewed from the side

Reference Lines:

• A line from forehead to point A
• A line from point A to pogonion

Types Of Profiles:

• Straight: Two lines straight line Ex. Class 1 cases
• Convex: Two lines form an angle with concavity facing tissue Ex. Class 2, Division 1
• Concave: Two lines form an angle with convexity facing tissue Ex. Class 3 malocclusion

Question 6. Importance of Family History.
Answer.

• Some malocclusions are hereditary
• These affect the treatment planning
• Thus details of it should not be neglected Ex. Class 2 malocclusion, Cleft lip and palate

Question 7. Kesling’s diagnostic setup.
Answer.

• Proposed by H.D. Kesling
• Used for assessing the effect of treatment

Procedure Of Kesling’s Diagnostic:

Question 8. Freeway Space.
Answer.

• The position of the mandible at which muscles that are useful in opening and closing of jaws are in a state of minimal contraction is called posture rest position
• At this position, space is present between both the jaws
• This is called free-way space

Value – 3mm

Site – In canine region

Question 9. Gnathostatic Models.
Answer.

• Type of study model
• Uses: Provide 3D view of occlusion
• For treatment planning
• For assessing the outcome

Gnathostatic:

Question 10. Overjet.
Answer.

• It is a horizontal overlapping of the maxillary and mandibular anterior
• Value: 1.5 – 2mm
• Significance Of Overjet: Increases in open bite cases
  • Increases in anterior proclination

Question 11. Nasolabial angle.
Answer.

• It is the angle formed between the lower border of the nose and the line connecting the intersection of the nose and the upper lip
• It is normally 110 degrees
• Reduces in
  • Patients having proclined upper anterior or prognathic maxilla
• Increases in
  • Patients with retrognathic maxilla or reclined maxillary anterior

Question 12. Cephalic index
Answer.

• The cephalic index was described by Martin and Saller in 1957
  • It is calculated as follows
• Cephalic index = Maxillary skull width / Maxillary skull length

Interpretation Of Cephalic Index:

• Value – 76-80.9
  • Indicates mesocephalic individuals
• Value – 81-85.4
  • Indicates brachycephalic individuals
• Value < 75.9
  • Indicates dolichocephalic individuals
• Value > 85.5
  • Indicates hyperbradycephalic

Question 13. Orthodontic study models
Answer.

Uses Of Orthodontic Study Models:

• Studies occlusion from all aspects
• Enables accurate measurement
• Treatment planning
• Assess the severity of malocclusion
• Motivate the patient
• For mock surgery
• For transparency records

Requirements Of Orthodontic Study Models:

• Should accurately reproduce oral structures
• Should be pleasing to the eye
• Should accurately reproduce occlusion
• Should have a clean, smooth surface
• Should reproduce as much of the alveolar process as possible

Parts Of Orthodontic study models:

• Anatomic portion
• Artistic portion

Question 14. Importance of medical history
Answer.

• Some medical conditions contraindicate the use of orthodontic appliances
• They may require special precautionary measures to be taken before or during orthodontic therapy
• It is advisable to delay orthodontic treatment in patients suffering from epilepsy until it is controlled
• Patients with a history of blood dyscrasias may need special management if extractions are planned
• Diabetic patients can undergo orthodontic therapy if it is under control
• Patients having rheumatic fever or cardiac anomalies require antibiotic coverage for certain dental procedures
• Children who are severely handicapped either mentally or physically may require special management
• The use of aspirin may impede orthodontic tooth movement
• Patients suffering from acute, debilitating conditions should be allowed to recover before initiating orthodontic treatment

Orthodontic Diagnosis Viva Voce

• Hyperactive mental activity and abnormal buccinators activity are seen in class 2 division 1
• Overclosure of jaws is associated with accentuated temporalis muscle activity
• Normally the upper lip covers the anterior labial surface of the upper anterior except for the incisal 2-3mm while the lower lip covers the entire labial surface of the lower anterior and 2–3mm of the incisal edge of the upper anterior