DIAGNOSTIC SET UP

INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com
www.indiandenta...
Seminar on,

Diagnostic Set up
Panoramic Radiography
Xeroradiography
Clark’s technique

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DIAGNOSTIC SET UP
 Practical aid in treatment planning and
diagnosis.
 Proposed by H.D. Kingsley.
 It’s a procedure in ...
Advantages –
1. To determine and visualise the resultant
occlusion before the teeth have been extracted
2. Possible to cha...
4. Tooth size – arch length discrepancies can be
visualised by means of set up.
5. Also a step in construction of tooth po...
Procedure
A set of well trimmed models made of deep
impressions of teeth and soft tissues.
Lines are drawn through bucca...
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 The lower first permanent molars are replaced to a new
position they will occupy by mesial migration.
 Deciding lower f...
 After all the above points have been considered, the
orthodontist must anticipate the behaviour of anchor
molar during t...
 Maxillary teeth are arranged according to mandibular
teeth to obtain best possible occlusion.

 In most cases, same no....
‘A Simplified wax set up technique’
by R.W. Knierim JCO- 1975
According to his procedure –
 Plaster is filled to about 4 ...
 Teeth are then separated using discs on a lathe to
slice root area, most teeth will now snap apart.
 Root areas are the...
 The trimmed dies are then reinserted in air dried alginate
impression

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 Melted wax is then poured in impression holding the
dies, it should flow well in grooves.

.

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 Similar grooves are then placed in surface of wax
as it hardens

 Plaster is poured over wax surface to make base for m...
‘A simplified Diagnostic set up technique.’ by Dr.
Barry N. Resnick; 1979 JCO
 According to his procedure –
 The plaster...
 Original study model.

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 Alginate impression with
selected teeth poured up
in stone to the extent of
their clinical crowns.

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 Dental units and model
base connected by
periphery wax.

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 Diagnostic set up with
mandibular left lateral
incisor removed and
remaining teeth aligned.

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Panoramic
Radiography

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Panoramic Radiography
 Also called as Ortho pantomograph (OPG)
 Rotational Radiography.
 It is a radiographic technique...
Advantages1. Broad anatomic coverage
2. Simple procedure
3. Better tolerated by pts with gagging problems
4. Low radiation...
Disadvantages
1.

Magnification, Geometric distortion and overlapped
images.

2.

Resolution of fine anatomic details of p...
Indications
1.
2.
3.
4.
5.
6.

To assess pattern and amount of root resorption of
deciduous teeth.
Useful in mixed dentiti...
7. To study morphology and angulations of roots of
permanent teeth.
8. To study the path of eruption of teeth.
9. To diagn...
 To interpret OPG competently one
must have a thorough understanding
of the following :
1. Principles of Panoramic image ...
Principles of Panoramic image formation
 First described by Numata and independently by
Paatero in late 1940s.

Movement ...
Movement of film and X- ray source about one
fixed center of rotation.

 While disc 2 moves, the film on this disc rotate...
Rotational Panaromic radiographic
machines.

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Focal Trough
 It’s a 3-D curved zone or image layer in which
structures are reasonably well defined on OPG.
 The images ...
Movement of the film and x-ray source
about the shifting center of rotation.

 Structures near the film will be sharply i...
 Ring at center
of FT.

 Ring 5mm
anterior to FT

 Ring 5 mm
posterior to FT

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Patient positioning and Head alignment.
 Prepration of Patients.
– Removal of earrings or any other metallic objects in h...
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If anterior teeth are located behind the FT
- Blurred
- Wide anterior teeth

If anterior teeth are located infront of the ...
Correct position using bite block

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If skull tipped too far backward

Position the skull according to FH plane and check for
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occlu...
If skull tipped too far forward

Position the skull according to FH plane and check for
occlusal plane
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Deviation in mid sagittal plane

Asymmetric image

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Positioning in mixed dentition stage
•The tooth buds should be in FT
•If additional supernumerary teeth
or impacted teeth ...
Positioning of the Tongue

Pt should press tongue against palate
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Radiation dose reduction
 By using rare-earth intensifying screens.
 Reduce the output by using filters infront of x-ray...
Radiographic appearance of
normal Anatomy

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The four Diagnostic regions in OPG
Dentoalveolar region

Mandibular region

TMJ,including retromaxillary
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Maxillary
region

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Mandibular
region

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Dentoalveolar region

• Shape and angulation of roots.
• Alveolar bone and periodontium
• Shows gentle curve of occlusal p...
Soft tissue images

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Air spaces

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Xeroradiography

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Xeroradiography


Xeroradiography is the recording of
radiologic images by a photoelectric process
rather than the photoc...
Advantages
Pronounced edge enhancement
A choice of positive and negative display
Good detail
Wide exposure latitude
N...
Types of Xeroradiographic systems
 Two types –
1. The Medical 125 system
– Used since 1970s.
– Used manly in Mammography ...
Medical Xeroradiography
Conventional X-ray source is needed.
Image is recorded in Selenium coated plate.
Before use, se...
Processing of Xeroplate before exposure

Plate is subjected to Relaxation
process.
Eliminates old images and
artefacts fro...
Exposure of Xeroplate

Latent image

Latent image is converted to visible image by
process called Development, in unit cal...
Development of Image

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Positive Image
 When a positive voltage is applied to back of of the
photoreceptor – negative toner particles get attract...
Negative image
 When a negative voltage is applied to back of of the
photoreceptor – positive toner particles get attract...
Dental xeroradiography
 Dental 110 xeroradiogrphic unit system is similar to
medical 125 system in concept but its design...
Dental xeroradiographic processor.

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Dental xeroradiographic procedure.

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Radiologic exposure conditions and resultant skin doses
in application of Xeroradiography to Orthodontic
diagnosis. AJO-DO...
 Landmarks on cephlaogram such as Sella, ANS,Basion,
etc were more clear and exactly set.
 Outline of condylar process a...
A cephalometric appraisal of Xeroradiography
by Chate – AJO-DO 1980
 This study involved identification by four observers...
Clark’s technique

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Localization technique
 Two methods are used in dentistry to obtain
3-D information –
1. To employ two films projected at...
Clark’s technique
C.A Clark described it in 1910.
Its based on Parallax principle in physics.
In this , 2 periapical fi...
The apparent movement of the object in this
radiograph will provide clue to its exact
location.
According to rule of thu...
Horizontal shift of central ray
Distal shift of cone

Cone shift

Cone shift

Standard

Standard
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Vertical shift of central ray

Standard

Standard

Vertical shift

Vertical shift
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References (Diagnostic set up)
1.
2.
3.
4.

Begg Orthodontics Theory & Technique – Kesling
Diagnosis and treatment plannin...
References (Radiology)
1.
2.







Oral radiology – Goaz & White.
A Colour Atlas of Dental Radiology – Friedrich A
P...
INDICES

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Index
According to Russell, an index is defined as
‘A numerical value describing the relative status
of the population on ...
General requirements of an Index.
- WHO 1977
1.
2.
3.
4.
5.
6.

Reliable
Valid
Acceptable to profession and public.
Requir...
 Ideal occlusal index should possess the
following properties1.
2.
3.
4.
5.

Reliability
Validity
It should be amenable t...
According to Jamison H.D. and Mc Millan R.S
requirements of ideal orthodontic index used
for epidemiologic studies are –
...
Types of Indices ( according to WHO)
 Occlusal Classification
– Angle’s classification by Angle in 1899
– Incisor classif...
 Treatment assessment
– Little’s irregularity index by Little 1975
– Peer Assessment rating by Richmond et al, 1992
 Cle...
Types Of Indices
According to Shaw , Richmond and O’Brien
 Diagnostic Classification
– Angle’s classification
– Incisor c...
 Treatment need ( Treatment priority) indices.
– Categorize malocclusion according to levels of treatment
needs.
– Eg 1. ...
Various indices of Occlusion
 Master and Frankel (1951)
– Count the number of teeth displaced or rotated
– Assessment of ...
Occlusal feature index by Poulton and
Aaronson (1961)
 Measurement of
–
–
–
–

Anterior crowding
Cuspal interdigitation
O...
Handicapping Labio – Lingual deviation index
by Draker (1960)
 Applicable only to permanent dentition.
 The sagittal pla...
The 7 conditions of HLD index are
1.
2.
3.
4.
5.
6.
7.

Cleft palate
Traumatic deviations.
Overjet
Overbite
Mandibular pr...
Conditions observed
1.
2.
3.
4.
5.
6.
7.
8.
9.

HLD score

Cleft palate
Score 15
Severe Traumatic deviations
Score 15
Over...
Handicapping Labio – Lingual deviation index
by Draker (1960)
 Applicable only to permanent dentition.
 The sagittal pla...
The 7 conditions of HLD index are
1.
2.
3.
4.
5.
6.
7.

Cleft palate
Traumatic deviations.
Overjet
Overbite
Mandibular pr...
Conditions observed
1.
2.
3.
4.
5.
6.
7.
8.
9.

HLD score

Cleft palate
Score 15
Severe Traumatic deviations
Score 15
Over...
Occlusal index by Summers (1966)
 Nine weighted and defined measurements –
1.
2.
3.
4.
5.
6.
7.
8.
9.

Molar relation
Ove...
 Seven malocclusion syndromes defined
1.
2.
3.
4.
5.
6.
7.



Overjet and open bite
Distal molar relation, overjet, over...
Treatment priority index by Grainger
(1967)
 The precursor of the TPI was the Malocclusion Severity
Estimate (MSE) develo...
Treatment priority index by Grainger (1967)



Malocclusion types –
Crowding /Malalignment problems
– Tooth displacement...
 TPI is based on a scale of
1.
2.
3.
4.

0 (near ideal occlusion)
1 - 3 ( mild malocclusion)
4 – 6 ( Moderate malocclusio...
Handicapping malocclusion assessment
records by Salzmann (1968)


1.

The purpose of HMAR – To establish priority for
tr...
Six handicapping dento-facial deformities
1.
2.
3.
4.
5.
6.

Facial and oral clefts
Lower lip palatal to maxillary incisor...
Instruction for Scoring

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Index of Treatment Need (IOTN)
by Shaw
 Index has two components1.
2.



Dental Health component – derived from occlusio...
A special ruler summarizes the information
needed for dental health component.
 Assessed in order :
1. Missing teeth
2. ...
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Esthetic Index
 Grades 8 – 10 =
definite need for
treatment.
 5 – 7 = moderate/
borderline need
 1 – 4 = No/ slight
nee...
Peer assessment rating Index (PAR index)
Index of orthodontic treatment outcome



Developed by 10 experienced British or...
5 components-

Weighting
1. Upper & lower anterior segment - 1
2. Left and right buccal segments 1
3. Over jet
- 6
4. Ove...

1.
2.





Change expressed as:
Reduction in weighted PAR score : 22 point
reduction – Greatly improved
% reduction i...
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TheValidation of PAR for Malocclusion severity
and Treatment Difficulty
De Guzman,bahiraei, Vig, Weyant and O’Brien – AJO-...
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Index of Complexity Outcome and Need
(ICON)


Based on expert opinions of 97 orthodontists from
various countries.



Fo...
 5 components taking about 1 min to measure.
1. Aesthetic component
 10 pictures

1. Upper arch Crowding/ Spacing
 Scor...
1. Aesthetic component

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ICON Scoring Method

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Goslon yardstick :A new system of assessing
dental arch relationships in childeren with UCLP – Michael
Mars, Dennis A. Pli...

1.
2.
3.




Development of Yardstick – Clinical features
considered most important in characterizing
malocclusion in ...
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 Group 1 – excellent





Group 2 – good
Group 3 – fair
Group 4 – poor
Group 5 – very poor

 Group 1 or 2 - simple o...
Application of yardstick
 Stage 1 – A-P assessment
 Stage 2 – Vertical assessment
 Stage 3 – Transverse assessment

www...
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Leader in continuing dental education

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Diagnostic set up /certified fixed orthodontic courses by Indian dental academy

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The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.

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Diagnostic set up /certified fixed orthodontic courses by Indian dental academy

  1. 1. DIAGNOSTIC SET UP INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com 1
  2. 2. Seminar on, Diagnostic Set up Panoramic Radiography Xeroradiography Clark’s technique www.indiandentalacademy.com 2
  3. 3. DIAGNOSTIC SET UP  Practical aid in treatment planning and diagnosis.  Proposed by H.D. Kingsley.  It’s a procedure in which teeth are removed and replaced in positions they will occupy after experiencing mesial migration in an orthodontic environment. www.indiandentalacademy.com 3
  4. 4. Advantages – 1. To determine and visualise the resultant occlusion before the teeth have been extracted 2. Possible to change the treatment plan on the model by replacing some and removing other teeth so that one can thoroughly examine all possible occlusions. 3. Mainly useful in asymmetric extraction and combined surgical orthodontic treatment. www.indiandentalacademy.com 4
  5. 5. 4. Tooth size – arch length discrepancies can be visualised by means of set up. 5. Also a step in construction of tooth positioner. 6. Patient can be motivated . www.indiandentalacademy.com 5
  6. 6. Procedure A set of well trimmed models made of deep impressions of teeth and soft tissues. Lines are drawn through buccal groove on the mandibular first molars on to the soft tissue. This act as a reference point. A . 004 inch ribbon saw blade is used to cut through the contact areas and separate teeth. www.indiandentalacademy.com 6
  7. 7. www.indiandentalacademy.com 7
  8. 8. www.indiandentalacademy.com 8
  9. 9. www.indiandentalacademy.com 9
  10. 10. www.indiandentalacademy.com 10
  11. 11. www.indiandentalacademy.com 11
  12. 12.  The lower first permanent molars are replaced to a new position they will occupy by mesial migration.  Deciding lower first molar position is the most important decision in constructing the set up.  Factors influencing position of first molar set up are – – Size of the teeth – Presence or absence of tooth crowding mesial to anchor molars. – Procumbency of anterior teeth. – Missing teeth – Age of the patient – Treatment plan – Tooth size related to jaw size. www.indiandentalacademy.com 12
  13. 13.  After all the above points have been considered, the orthodontist must anticipate the behaviour of anchor molar during treatment.  It again depends on – – – – – Technique employed The time requirement Orthodontist’s ability Patient’s cooperation  At this stage by studying the set up one can analyse that If anterior teeth – too far forward – Extraction – If already extracted – more extraction.  If anterior teeth – lingual – Eliminate planned extraction. www.indiandentalacademy.com 13
  14. 14.  Maxillary teeth are arranged according to mandibular teeth to obtain best possible occlusion.  In most cases, same no. and type of teeth are removed from maxillary arch as mandibular arch.  Exception – – Badly broken down teeth – Congenitally missing or deformed teeth. – Single tooth extraction in lower arch www.indiandentalacademy.com 14
  15. 15. ‘A Simplified wax set up technique’ by R.W. Knierim JCO- 1975 According to his procedure –  Plaster is filled to about 4 mm over gingival margin of impression.  As the plaster sets rough grooves are made in near set plaster to depth of 2mm.  When plaster is set it is removed and teeth are numbered. www.indiandentalacademy.com 15
  16. 16.  Teeth are then separated using discs on a lathe to slice root area, most teeth will now snap apart.  Root areas are then trimmed.  The impression are saved and kept moist. www.indiandentalacademy.com 16
  17. 17.  The trimmed dies are then reinserted in air dried alginate impression www.indiandentalacademy.com 17
  18. 18.  Melted wax is then poured in impression holding the dies, it should flow well in grooves. . www.indiandentalacademy.com 18
  19. 19.  Similar grooves are then placed in surface of wax as it hardens  Plaster is poured over wax surface to make base for model. www.indiandentalacademy.com 19
  20. 20. ‘A simplified Diagnostic set up technique.’ by Dr. Barry N. Resnick; 1979 JCO  According to his procedure –  The plaster is poured in impression only to the extent of clinical crown.  Soft wax of 5 mm thickness is poured over crown dies.  Remainder of impression is poured with plaster and allowed to set.  After separation from impression, the model consists of two plaster section connected by wax.  Teeth are marked and can be repositioned in desired way www.indiandentalacademy.com 20
  21. 21.  Original study model. www.indiandentalacademy.com 21
  22. 22.  Alginate impression with selected teeth poured up in stone to the extent of their clinical crowns. www.indiandentalacademy.com 22
  23. 23.  Dental units and model base connected by periphery wax. www.indiandentalacademy.com 23
  24. 24.  Diagnostic set up with mandibular left lateral incisor removed and remaining teeth aligned. www.indiandentalacademy.com 24
  25. 25. Panoramic Radiography www.indiandentalacademy.com 25
  26. 26. Panoramic Radiography  Also called as Ortho pantomograph (OPG)  Rotational Radiography.  It is a radiographic technique for producing single image of facial structures that includes both maxillary and mandibular arches and their supporting structures. www.indiandentalacademy.com 26
  27. 27. Advantages1. Broad anatomic coverage 2. Simple procedure 3. Better tolerated by pts with gagging problems 4. Low radiation dose 5. Convenience of the examination. 6. Useful in pts who are unable to open their mouth 7. Full mouth IOPA – 15 mins and OPG – 3-4 mins. www.indiandentalacademy.com 27
  28. 28. Disadvantages 1. Magnification, Geometric distortion and overlapped images. 2. Resolution of fine anatomic details of peri-apical area and periodontal structures is less. 3. Poor image is obtained when sharp inclination of anterior teeth towards labial or lingual side. 4. The spinal cord superimpose on anterior region. 5. Common to have overlapped teeth images , particularly in premolar area. 6. Artifacts are common and may easily be misinterpreted. 7. Expensive www.indiandentalacademy.com 28
  29. 29. Indications 1. 2. 3. 4. 5. 6. To assess pattern and amount of root resorption of deciduous teeth. Useful in mixed dentition period to study the status of unerupted teeth. Presence or absence of permanent teeth: their size, shape, position and relative state of development. To view ankylosed and impacted teeth. To diagnose presence of supernumerary teeth or congenital absence of teeth. To study the character of alveolar bone and immediate lamina dura and periodontal membrane. www.indiandentalacademy.com 29
  30. 30. 7. To study morphology and angulations of roots of permanent teeth. 8. To study the path of eruption of teeth. 9. To diagnose fractures or pathologies of jaw. 10. To diagnose caries, periapical infections root fractures etc. 11. Useful aid in serial extraction to study status of eruption of teeth. 12. Can assess TMJ and Sinuses. 13. Assess shape, size and symmetry of condyles. www.indiandentalacademy.com 30
  31. 31.  To interpret OPG competently one must have a thorough understanding of the following : 1. Principles of Panoramic image formation. 2. Techniques for Patient positioning with head alignment and their rationale. 3. Radiographic appearance of normal anatomic structures. www.indiandentalacademy.com 31
  32. 32. Principles of Panoramic image formation  First described by Numata and independently by Paatero in late 1940s. Movement of the film and objects about 2 fixed centers of rotation. www.indiandentalacademy.com 32
  33. 33. Movement of film and X- ray source about one fixed center of rotation.  While disc 2 moves, the film on this disc rotates past the slit.  It is critical that speed of the film passing the collimator slit is maintained equal to the speed at which x-ray beam sweeps through the object of interest. www.indiandentalacademy.com 33
  34. 34. Rotational Panaromic radiographic machines. www.indiandentalacademy.com 34
  35. 35. Focal Trough  It’s a 3-D curved zone or image layer in which structures are reasonably well defined on OPG.  The images seen on OPG consists largely of anatomic structures located within the focal trough.  Objects out of focal trough are blurred magnified/ reduced or distorted.  The shape of focal trough varies with brands of machines used. www.indiandentalacademy.com 35
  36. 36. Movement of the film and x-ray source about the shifting center of rotation.  Structures near the film will be sharply imaged.  Structures which are near x-ray source get magnified and distorted and resultant image is not discrete. www.indiandentalacademy.com 36
  37. 37.  Ring at center of FT.  Ring 5mm anterior to FT  Ring 5 mm posterior to FT www.indiandentalacademy.com 37
  38. 38. Patient positioning and Head alignment.  Prepration of Patients. – Removal of earrings or any other metallic objects in head and neck region. – Instruct patients to remain still. – Drape with lead apron.  Patient Positioning – Place the pt so that dental arches are located in middle of focal trough. – A-P positioning – by biting at bite block. – Proper mid sagittal plane –proper head positioning – cephalostat. – Occlusal plane and chin must be properly positioned – FH plane parallel with floor.. – Back and spine be erect with neck extended. www.indiandentalacademy.com 38
  39. 39. www.indiandentalacademy.com 39
  40. 40. www.indiandentalacademy.com 40
  41. 41. If anterior teeth are located behind the FT - Blurred - Wide anterior teeth If anterior teeth are located infront of the FT -Blurred -Narrow anterior teeth www.indiandentalacademy.com 41
  42. 42. Correct position using bite block www.indiandentalacademy.com 42
  43. 43. If skull tipped too far backward Position the skull according to FH plane and check for www.indiandentalacademy.com occlusal plane 43
  44. 44. If skull tipped too far forward Position the skull according to FH plane and check for occlusal plane www.indiandentalacademy.com 44
  45. 45. Deviation in mid sagittal plane Asymmetric image www.indiandentalacademy.com 45
  46. 46. Positioning in mixed dentition stage •The tooth buds should be in FT •If additional supernumerary teeth or impacted teeth has to be shown the pt must be positioned with occlusal plane steeply dorsally www.indiandentalacademy.com 46
  47. 47. Positioning of the Tongue Pt should press tongue against palate www.indiandentalacademy.com 47
  48. 48. Radiation dose reduction  By using rare-earth intensifying screens.  Reduce the output by using filters infront of x-ray tube. Eg. Lanex screens. www.indiandentalacademy.com 48
  49. 49. Radiographic appearance of normal Anatomy www.indiandentalacademy.com 49
  50. 50. The four Diagnostic regions in OPG Dentoalveolar region Mandibular region TMJ,including retromaxillary www.indiandentalacademy.com and cervical region Maxillary region 50
  51. 51. Maxillary region www.indiandentalacademy.com 51
  52. 52. Mandibular region www.indiandentalacademy.com 52
  53. 53. Dentoalveolar region • Shape and angulation of roots. • Alveolar bone and periodontium • Shows gentle curve of occlusal plane • Missing 3rd molars and • Presence of metallic restorations. www.indiandentalacademy.com 53
  54. 54. Soft tissue images www.indiandentalacademy.com 54
  55. 55. Air spaces www.indiandentalacademy.com 55
  56. 56. Xeroradiography www.indiandentalacademy.com 56
  57. 57. Xeroradiography  Xeroradiography is the recording of radiologic images by a photoelectric process rather than the photochemical one used in conventional radiography. An electrostatic image of object is formed on a ‘ Xeroplate’ , a metallic plate coated with Selenium. An electrostatic image is printed on a paper in such a manner that xeroradiograph is obtained. www.indiandentalacademy.com 57
  58. 58. Advantages Pronounced edge enhancement A choice of positive and negative display Good detail Wide exposure latitude No need of silver halide coated films. Disadvantages High radiation exposure www.indiandentalacademy.com 58
  59. 59. Types of Xeroradiographic systems  Two types – 1. The Medical 125 system – Used since 1970s. – Used manly in Mammography and general radiography. – Also been used for cephalometric radiography and tomography of TMJ 1. The Dental 110 system  Designed for dental Xeroradiographs www.indiandentalacademy.com 59
  60. 60. Medical Xeroradiography Conventional X-ray source is needed. Image is recorded in Selenium coated plate. Before use, selenium photoreceptors which are stored in a unit called conditioner are given a uniform electrostatic charge www.indiandentalacademy.com 60
  61. 61. Processing of Xeroplate before exposure Plate is subjected to Relaxation process. Eliminates old images and artefacts from surface. Plates are then electrostatically charged and inserted to cassette. www.indiandentalacademy.com 61
  62. 62. Exposure of Xeroplate Latent image Latent image is converted to visible image by process called Development, in unit called Processor www.indiandentalacademy.com 62
  63. 63. Development of Image www.indiandentalacademy.com 63
  64. 64. Positive Image  When a positive voltage is applied to back of of the photoreceptor – negative toner particles get attracted to the surface so, highly charged areas receive more toner particles than discharged areas.  This results in positive image where darkest areas corresponds to most dense parts of anatomy. www.indiandentalacademy.com 64
  65. 65. Negative image  When a negative voltage is applied to back of of the photoreceptor – positive toner particles get attracted to the discharged areas .  This results in negative image where darkest areas corresponds to least dense parts of anatomy and dense objects appear white. www.indiandentalacademy.com 65
  66. 66. Dental xeroradiography  Dental 110 xeroradiogrphic unit system is similar to medical 125 system in concept but its design is physically different.  The image receptor plates are the size no. 1 and no. 2 films and fit well in oral cavity. www.indiandentalacademy.com 66
  67. 67. Dental xeroradiographic processor. www.indiandentalacademy.com 67
  68. 68. Dental xeroradiographic procedure. www.indiandentalacademy.com 68
  69. 69. Radiologic exposure conditions and resultant skin doses in application of Xeroradiography to Orthodontic diagnosis. AJO-DO, 1980 by Akihiko Nakasima (Japan )  Minimum xeroradiologic exposure conditions for Skull projections, Schuller’s and TMJ projections and Hand projections were established by 13 examiners and relation b/w image production and radiation dose was discussed in comparison with conventional film techniques.  The advantages were finer and clearer images due to edge effect and wider latitude. www.indiandentalacademy.com 69
  70. 70.  Landmarks on cephlaogram such as Sella, ANS,Basion, etc were more clear and exactly set.  Outline of condylar process and articular fossa, the trabecular pattern of mandible and interdental crestal bone edges were more clear and distinct.  The main hazard was unavoidable larger skin radiation dose . It was 2.4 to 16.2 times larger than conventional film techniques. www.indiandentalacademy.com 70
  71. 71. A cephalometric appraisal of Xeroradiography by Chate – AJO-DO 1980  This study involved identification by four observers of 16 cephalometric landmarks on 12 xeroradiographs & on 12 radiographs, on 2 separate occasions.  The conclusion was that neither technique provided a significant intraobserver differences. However, for 8 of 32 variables xeroradiography produced a significant reduction in intraobserver error in comparison to radiography. www.indiandentalacademy.com 71
  72. 72. Clark’s technique www.indiandentalacademy.com 72
  73. 73. Localization technique  Two methods are used in dentistry to obtain 3-D information – 1. To employ two films projected at right angle to each other. 2. Tube shift/cone shift principle or Clark’s technique or buccal object rule or SLOB rule.  Mainly used in Orthodontia to locate position of impacted canine. www.indiandentalacademy.com 73
  74. 74. Clark’s technique C.A Clark described it in 1910. Its based on Parallax principle in physics. In this , 2 periapical films are taken, first is taken as standard orthoradial projection, while second employs a vertical or horizontal change in central ray projection. www.indiandentalacademy.com 74
  75. 75. The apparent movement of the object in this radiograph will provide clue to its exact location. According to rule of thumb objects which moves with central ray movement are actually behind the reference object. Its basis of SLOB rule, that is Same side Lingual Opposite side Buccal www.indiandentalacademy.com 75
  76. 76. Horizontal shift of central ray Distal shift of cone Cone shift Cone shift Standard Standard www.indiandentalacademy.com 76
  77. 77. Vertical shift of central ray Standard Standard Vertical shift Vertical shift www.indiandentalacademy.com 77
  78. 78. References (Diagnostic set up) 1. 2. 3. 4. Begg Orthodontics Theory & Technique – Kesling Diagnosis and treatment planning in Orthodontics – Van der Linden A Simplified wax set up technique by Dr. R.W. Knierim JCO-1975. A simplified Diagnostic set up technique by Dr. Barry N. Resnick; 1979 JCO. www.indiandentalacademy.com 78
  79. 79. References (Radiology) 1. 2.      Oral radiology – Goaz & White. A Colour Atlas of Dental Radiology – Friedrich A Pasler. Essentials of Dental Radiography – Orien N Johnson. Principles of Dental Imaging – Langland. Orthodontics - T. M .Graber. Radiologic exposure conditions and resultant skin doses in application of xeroradiography to Orthodontic diagnosis by Akihiko Nakasima AJODO, 1980 . A cephalometric appraisal of Xeroradiography by Chate AJO-DO 1980. www.indiandentalacademy.com 79
  80. 80. INDICES www.indiandentalacademy.com 80
  81. 81. Index According to Russell, an index is defined as ‘A numerical value describing the relative status of the population on a graduated scale with definite upper and lower limits which is designed to permit and facilitate comparison with other population classified with the same criteria and the method.’ In the orthodontic context index is described as – ‘A rating or categorizing system that assigns a numeric score or alpha numeric label to a person’s occlusion.’ www.indiandentalacademy.com 81
  82. 82. General requirements of an Index. - WHO 1977 1. 2. 3. 4. 5. 6. Reliable Valid Acceptable to profession and public. Require minimal judgement Administratively simple Cheap www.indiandentalacademy.com 82
  83. 83.  Ideal occlusal index should possess the following properties1. 2. 3. 4. 5. Reliability Validity It should be amenable to modifications. It must yield quantitative data. It should lend itself to rapid application by trained examiners. www.indiandentalacademy.com 83
  84. 84. According to Jamison H.D. and Mc Millan R.S requirements of ideal orthodontic index used for epidemiologic studies are – 1. Simple, accurate, reliable and reproducible. 2. Objective and yield quantitative data. 3. Differentiate b/w handicapping and non handicapping malocclusions. 4. Quick examination. 5. Amenable to modifications. 6. Usable either on patient or on study model. 7. Measure degree of handicap. www.indiandentalacademy.com 84
  85. 85. Types of Indices ( according to WHO)  Occlusal Classification – Angle’s classification by Angle in 1899 – Incisor classification by Ballard and wayman, 1964  Skeletal classification by Houstaon et al, 1993  Malocclusion – Occlusal index by Summers 1971 – Handicapping Malocclusion Assessment Record (HMAR) by Salzmann, 1968 – Index of Treatment Need by Evans and Shaw 1987 www.indiandentalacademy.com 85
  86. 86.  Treatment assessment – Little’s irregularity index by Little 1975 – Peer Assessment rating by Richmond et al, 1992  Cleft Outcome – Goslon Yardstick by Mars et al, 1987 – 5Year olds’ Index by Atack et al ,1997  Periodontal – Plaque Index by Stilness & Loe , 1964 – Gingival Index. by Loe & Stilness, 1963 www.indiandentalacademy.com 86
  87. 87. Types Of Indices According to Shaw , Richmond and O’Brien  Diagnostic Classification – Angle’s classification – Incisor classification  Epidemiologic indices – Study prevalence of malocclusion in population. – Eg 1.Summer’s occlusal index. 2. Registration of malocclusion described by Bjork, Krebs and Solow www.indiandentalacademy.com 87
  88. 88.  Treatment need ( Treatment priority) indices. – Categorize malocclusion according to levels of treatment needs. – Eg 1. IOTN 2. Draker’s HLD index 3. Grainger’s treatment priority index. 4. Salzman’s handicapping malocclusion index  Treatment outcome indices. – Assesssment of changes resulting from treatment – Eg 1. PAR index 2. Summer’s index  Treatment complexity index – ICON www.indiandentalacademy.com 88
  89. 89. Various indices of Occlusion  Master and Frankel (1951) – Count the number of teeth displaced or rotated – Assessment of tooth displacement and rotation is qualitative  Malalignment Index byVankrik and Pennel (1959) – Tooth displacement and rotations were measured. – Tooth displacement defined quantitatively : < 1. 5 mm or > 1. 5mm – Tooth rotation defined quantitatively : < 45 degree or > 45 degree www.indiandentalacademy.com 89
  90. 90. Occlusal feature index by Poulton and Aaronson (1961)  Measurement of – – – – Anterior crowding Cuspal interdigitation Overbite Overjet www.indiandentalacademy.com 90
  91. 91. Handicapping Labio – Lingual deviation index by Draker (1960)  Applicable only to permanent dentition.  The sagittal plane, FH plane and orbital plane commonly used in orthodontics are basis for HLD index.  Main aim is to find presence or absence and degree of handicap caused by components of index.  All measurements are made with Boley gauge scaled in mm. www.indiandentalacademy.com 91
  92. 92. The 7 conditions of HLD index are 1. 2. 3. 4. 5. 6. 7. Cleft palate Traumatic deviations. Overjet Overbite Mandibular protrusion Open bite Labio- Lingual spread www.indiandentalacademy.com 92
  93. 93. Conditions observed 1. 2. 3. 4. 5. 6. 7. 8. 9. HLD score Cleft palate Score 15 Severe Traumatic deviations Score 15 Overjet in mm Overbite in mm Mandibular protrusion in mm x5 Open bite in mm x4 Ectopic eruption ,Anteriors only each tooth x3 Anterior crowding : Maxilla Anterior crowding : Mandible TOTAL  A score of 13 and over constitutes a physical handicap. www.indiandentalacademy.com 93
  94. 94. Handicapping Labio – Lingual deviation index by Draker (1960)  Applicable only to permanent dentition.  The sagittal plane, FH plane and orbital plane commonly used in orthodontics are basis for HLD index.  Main aim is to find presence or absence and degree of handicap caused by components of index.  All measurements are made with Boley gauge scaled in mm. www.indiandentalacademy.com 94
  95. 95. The 7 conditions of HLD index are 1. 2. 3. 4. 5. 6. 7. Cleft palate Traumatic deviations. Overjet Overbite Mandibular protrusion Open bite Labio- Lingual spread www.indiandentalacademy.com 95
  96. 96. Conditions observed 1. 2. 3. 4. 5. 6. 7. 8. 9. HLD score Cleft palate Score 15 Severe Traumatic deviations Score 15 Overjet in mm Overbite in mm Mandibular protrusion in mm x5 Open bite in mm x4 Ectopic eruption ,Anteriors only each tooth x3 Anterior crowding : Maxilla Anterior crowding : Mandible TOTAL  A score of 13 and over constitutes a physical handicap. www.indiandentalacademy.com 96
  97. 97. Occlusal index by Summers (1966)  Nine weighted and defined measurements – 1. 2. 3. 4. 5. 6. 7. 8. 9. Molar relation Over jet Overbite Posterior cross bite Posterior open bite Tooth displacement Midline relation Maxillary median diastema Congenitally missing maxillary incisors. www.indiandentalacademy.com 97
  98. 98.  Seven malocclusion syndromes defined 1. 2. 3. 4. 5. 6. 7.  Overjet and open bite Distal molar relation, overjet, overbite, posterior crossbite, midline diastema and mid line deviation. Congenitally missing maxillary incisors. Tooth displacement. ( actual and Potential) Posterior open bite. Mesial molar relation, overjet, overbite, posterior crossbite, midline diastema and mid line deviation. Mesial molar relation, mixed dentition analysis (potential tooth displacement) and tooth displacement. Different scoring schemes and forms for different stages of dental development: Deciduous, Mixed & Permanent dentition. www.indiandentalacademy.com 98
  99. 99. Treatment priority index by Grainger (1967)  The precursor of the TPI was the Malocclusion Severity Estimate (MSE) developed by Grainger at the Burlington Orthodontic Research Center.4 in 1960-61  Unlike the TPI, the MSE score was that of the syndrome with the largest value, regardless of the scores of the other syndromes.  In the MSE the absence of occlusal disorders was not scored as zero.  The TPI also differed from the MSE by deleting potential tooth displacement (mixed-dentition space analysis) and by rating distoclusion and mesioclusion equally. www.indiandentalacademy.com 99
  100. 100. Treatment priority index by Grainger (1967)   Malocclusion types – Crowding /Malalignment problems – Tooth displacement – – –  Score 0 (ideal) Score 1 – 5 (moderate) Score > 5 ( severe) Anteroposterior problems – –  Overjet 6 mm or more Lower overjet 1mm or more Vertical problems – –  Open bite 2mm or more Over bite 6mm or more Transverse problems – – Lingual crossbite 2 or more teeth Buccal crossbite 2 or more teeth www.indiandentalacademy.com 100
  101. 101.  TPI is based on a scale of 1. 2. 3. 4. 0 (near ideal occlusion) 1 - 3 ( mild malocclusion) 4 – 6 ( Moderate malocclusion) Over 6 ( severe malocclusion)  TPI scores only occlusal characteristics, excluding skeletal and facial components.  TPI is used in national studies of orthodontic needs for children. www.indiandentalacademy.com 101
  102. 102. Handicapping malocclusion assessment records by Salzmann (1968)   1. The purpose of HMAR – To establish priority for treatment according to severity as shown by score. Weighted measurements consists of 3 parts – Intra arch deviations Missing teeth Crowding Rotation Spacing 1. Interarch deviations Overjet Overbite Crossbite Openbite www.indiandentalacademy.com Mesiodistal deviations 102
  103. 103. Six handicapping dento-facial deformities 1. 2. 3. 4. 5. 6. Facial and oral clefts Lower lip palatal to maxillary incisors. Occlusal interferences Functional jaw limitations Facial asymmetry Speech impairment.  Score 8 points for each deviation. www.indiandentalacademy.com 103
  104. 104. Instruction for Scoring www.indiandentalacademy.com 104
  105. 105. www.indiandentalacademy.com 105
  106. 106. Index of Treatment Need (IOTN) by Shaw  Index has two components1. 2.  Dental Health component – derived from occlusion and alignment. Aesthetic component – Derived from comparison of dental appearance to standard photographs. IOTN is usually calculated by direct examination, but dental health component can be studied by dental casts. www.indiandentalacademy.com 106
  107. 107. A special ruler summarizes the information needed for dental health component.  Assessed in order : 1. Missing teeth 2. Overjet 3. Crossbites 4. Displacements (Contact point) 5. Overbite www.indiandentalacademy.com 107
  108. 108. www.indiandentalacademy.com 108
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  110. 110. Esthetic Index  Grades 8 – 10 = definite need for treatment.  5 – 7 = moderate/ borderline need  1 – 4 = No/ slight need www.indiandentalacademy.com 110
  111. 111. Peer assessment rating Index (PAR index) Index of orthodontic treatment outcome  Developed by 10 experienced British orthodontists.  Its developed mainly to assess effectiveness of Orthodontic treatment .  Assigns scores to different occlusal traits.  Study models used.  A scoring system was developed and a ruler designed to allow analysis of a set of study casts in 2 minutes. www.indiandentalacademy.com 111
  112. 112. 5 components- Weighting 1. Upper & lower anterior segment - 1 2. Left and right buccal segments 1 3. Over jet - 6 4. Overbite - 2 5. Centerlines - 4  Individual scores are summed to get a final score..  Index is applied to both the start and end of treatment study casts, and change in total score reflects the success of treatment. www.indiandentalacademy.com 112
  113. 113.  1. 2.    Change expressed as: Reduction in weighted PAR score : 22 point reduction – Greatly improved % reduction in weighted PAR score: < 30% reduction – worse/ no better > 30% reduction – Improved. Indicator of clinical performance. Can be insensitive and misjudge individual patient’s needs. Limitations of PAR 1. Generic weightings of Over jet and overbite. 2. Sensitive to malocclusion with high over jet. 3. Overbite low weighting. 4. Zero weighting for displacements. www.indiandentalacademy.com 113
  114. 114. www.indiandentalacademy.com 114
  115. 115. TheValidation of PAR for Malocclusion severity and Treatment Difficulty De Guzman,bahiraei, Vig, Weyant and O’Brien – AJO-DO 1995  11 American Orthodontists examined a sample of 200 sets of study casts and rated them for malocclusion severity and perceived treatment difficulty.  The results of this study made it possible to derive a set of weightings for the PAR index that would represent groupings of malocclusion severity and treatment difficulty, according to perceptions of panel of Orthodontists. www.indiandentalacademy.com 115
  116. 116. www.indiandentalacademy.com 116
  117. 117. Index of Complexity Outcome and Need (ICON)  Based on expert opinions of 97 orthodontists from various countries.  For use on patients and Dental casts.  A single assessment method to record complexity, outcome and need. www.indiandentalacademy.com 117
  118. 118.  5 components taking about 1 min to measure. 1. Aesthetic component  10 pictures 1. Upper arch Crowding/ Spacing  Score according to amount of crowding or spacing  Impacted teeth in either arch immediately scored 5  Spacing in one part can cancel out crowding elsewhere. 1. Crossbite 2. Incisor open bite/ overbite  Open bite measured at mid incisal edges  Deep bite is measured at deepest part of overbite. 1. Buccal segment Antero posterior  Quality of buccal segment interdigitation is measured (not Angles Classification) www.indiandentalacademy.com 118
  119. 119. 1. Aesthetic component www.indiandentalacademy.com 119
  120. 120. ICON Scoring Method www.indiandentalacademy.com 120
  121. 121. www.indiandentalacademy.com 121
  122. 122. Goslon yardstick :A new system of assessing dental arch relationships in childeren with UCLP – Michael Mars, Dennis A. Plint : 1987 A cleft Palate journal  The Goslon ( Great Ormond Street, London and Oslo) Yardstick is a clinical tool that allows categorization of the dental relationships in the late mixed and or early permanent dentition in to 5 discrete categories.  Objective : 1. To categorize malocclusions in patients with UCLP to represent severity of malocclusion and the difficulty of correcting it. 2. To compare long term results of different approaches to the early treatment of children with UCLP. www.indiandentalacademy.com 122
  123. 123.  1. 2. 3.   Development of Yardstick – Clinical features considered most important in characterizing malocclusion in children with UCLP are – A- P arch relationship –Class III incisor relationship> class II div I Vertical labial segment relationship – Open bite> Reduced overbite > deep overbite. Transverse relationship – Canine crossbites > molar crossbites. To test the application of these subjective criteria study models of 30 cases were taken. These models were ranked by 4 orthodontists and separated in 5 groups , which then formed basis for yardstick. www.indiandentalacademy.com 123
  124. 124. www.indiandentalacademy.com 124
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  129. 129.  Group 1 – excellent     Group 2 – good Group 3 – fair Group 4 – poor Group 5 – very poor  Group 1 or 2 - simple orthodontic treatment/ no treatment  Group 3 – complex orthodontic treatment  Group 4 – limit of orthodontic treatment without orthognathic surgery  Group 5 – Orthognathic surgery www.indiandentalacademy.com 129
  130. 130. Application of yardstick  Stage 1 – A-P assessment  Stage 2 – Vertical assessment  Stage 3 – Transverse assessment www.indiandentalacademy.com 130
  131. 131. www.indiandentalacademy.com Leader in continuing dental education www.indiandentalacademy.com 131

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