1. Class I
Malocclusion Dr. Nabil Al-Zubair

2. or incorrect relation between the teeth of the two dental
arches. The term was coined by Edward Angle, the
"father of modern orthodontics", as a derivative of
occlusion, which refers to the manner in which opposing
teeth meet.
Malocclusion is a misalignment of teeth

3. Presence of alignment or Occlusal Features
Outside the Normal when the anteroposterior
incisor relationship is Class I.
• Definition
**Note: always when making Dx
we look at the incisors relationship.

4. 1) Class I malocclusion.
2) Bimaxillary protrusion
Most common forms are:

5. Class I
malocclusions
60%
Class II
malocclusions
32 %
PREVALENCE
This is the most common of all the malocclusions.

6. Extra-oral Features:
Intra-oral features
• Straight profile
• Harmonious face
• Average Vertical
Proportions
• Class I incisor relation
• Canine and molar relationships are
usually class I
• overjet is usually within average
• overBITE: normal, deep, reduced or open
bite
• Normal Bite, Crossbite or Scissor Bite

7. • Harmonious face
• Straight profile
• Nothing really
abnormal
Extra-oral Features of :
‫الوجه‬‫المتناسق‬
‫الجانبي‬ ‫التشكيل‬ ‫مستقيم‬

8. There is a harmonious growth between the upper and lower
jaw, which accounts for the skeletal and facial balance
Growth:

9. when the maxillary growth exceeds the mandibular
growth that will result in class II skeletal relationship.
On the other hand if the mandibular growth exceeds
the maxillary growth that will result in class III.
Harmonious Growth

10.  Average Vertical Proportions

11. **But some vertical and
transverse anomalies may be
found.
 Vertical and transverse:
**Within normal range
- LFH
- Frankfort mandibular angle

12.  The soft tissue form and activity are
usually within normal range
 Soft tissues (lips) :
 Favorable
‫إيجابي‬
is not aetiological factor.
This is a major factor in determining tooth position.
 Competent lips

13. The exception is (Bimaxillary proclination)
where
the upper & lower incisors are proclined.
the lips are full and everted.

14. (Bimaxillary proclination)
the lips are full and everted.
This may be duo to:
1- Racial in origin
2- Lack of lip tonicity results in the incisors
being moulded forwards under tongue
pressure.

15. DIAGNOSIS:

16. History
Clinical examination
Study models
Radiography
I. OPG
II. Periapical
III. Lateral ceph
DIAGNOSIS:

17. Intra-oral features

18. Intra-oral features
• Class I incisor relation
• Canine and molar relationships are usually
class I
• The overjet is usually within average
• Can be associated with normal overbite, deep,
reduced or open bite
• Can be associated with normal bite, crossbite or
scissor bite.

19. Problems associated with Class I:
• Crowding
• Spacing
• Deep Bite
• Open Bite
• Cross Bite
• Localized Teeth Problems
(impaction)

20. Crowding

21. Crowding: space deficiency The most common problem.
or
labial segment
buccal segment
both
It can be in
or
if there is a crowded dental arch, the last tooth
within the arch to erupt will often be impacted or
crowded out of the line of the dental arch.
‫تزاحم‬

22. 1. difficulty cleaning all tooth surfaces,
leading to more dental decay
2. an improper bite pattern
3. incorrect functioning of the teeth
4. an increased chance of developing
periodontal disease
5. an unattractive smile, leading to lower
self-esteem
Problems associated with crowding include:

23. •‫السليمة‬ ‫المضغ‬ ‫عملية‬ ‫إعاقة‬.
•‫خطورة‬ ‫يزيد‬ ‫مما‬ ‫األسنان‬ ‫نظافة‬ ‫على‬ ‫المحافظة‬ ‫صعوبة‬
‫اللثة‬ ‫أمراض‬ ‫أو‬ ‫والتهابات‬ ، ‫األسنان‬ ‫بتسوس‬ ‫اإلصابة‬.
•‫األحيان‬ ‫بعض‬ ‫في‬ ‫الفم‬ ‫وعضالت‬ ‫الفك‬ ‫و‬ ‫األسنان‬ ‫إجهاد‬
‫تحطم‬ ‫أو‬ ‫كسر‬ ‫خطورة‬ ‫من‬ ‫يزيد‬ ‫مما‬ ‫كبيرة‬ ‫بدرحة‬
‫األسنان‬.
•‫سلبية‬ ‫آثار‬ ‫من‬ ‫الشعور‬ ‫لهذا‬ ‫ما‬ ‫و‬ ‫باإلبتسامة‬ ‫الرضا‬ ‫عدم‬
‫بنفسه‬ ‫الشخص‬ ‫ثقة‬ ‫على‬.
‫األسنان؟‬ ‫تزاحم‬ ‫عواقب‬

24. Crowding is a condition where there is Malalignment of teeth caused by inadequate space
Definition
‫كافية‬ ‫غير‬ ‫مساحة‬ ‫وجود‬ ‫عدم‬ ‫بسبب‬‫االزدحام‬
‫ارتصاف‬ ‫سوء‬ ‫عن‬ ‫عبارة‬ ‫وهو‬‫لألسنان‬‫نقص‬ ‫عن‬ ‫ناجم‬
‫أو‬ ‫الفك‬ ‫حجم‬ ‫في‬ ‫صغر‬ ‫بسبب‬ ‫السنية‬ ‫القوس‬ ‫على‬ ‫المسافة‬/‫و‬
‫األسنان‬ ‫حجم‬ ‫في‬ ‫كبر‬,‫المخصصة‬ ‫المسافة‬ ‫ضياع‬ ‫بسبب‬ ‫أو‬
‫والوحشي‬ ‫األنسي‬ ‫األسنان‬ ‫انسالل‬ ‫نتيجة‬ ‫الدائمة‬ ‫لألسنان‬
‫شكل‬ ‫تغير‬ ‫بسبب‬ ‫أو‬ ‫اللبنية‬ ‫لألسنان‬ ‫المبكر‬ ‫القلع‬ ‫عن‬ ‫الناجم‬
‫الزائد‬ ‫والخدود‬ ‫الشفاه‬ ‫ضغط‬ ‫عن‬ ‫الناجم‬ ‫السنية‬ ‫القوس‬,‫كما‬
‫أدناه‬ ‫الصورة‬ ‫في‬
 Environmental Crowding Hereditary Crowding
1. Classification
Classification of Crowding
There are different methods of Classification of Crowding

25. Also called late
incisor crowding is
due to late
mandibular growth
Classification of Crowding
Determined Genetically
& is caused by
disproportion between
jaw size and teeth size
Primary crowding Secondary crowding
Tertiary crowding
Acquired crowding is
caused by loss of arch
length due to
Environmental cause

26. Crowding
Aetiology
Primary / hereditary crowding:-
(Determined genetically)
- discrepancy between the size of the teeth & the
size of the arches.
- Normal teeth & small dental arch
- Large teeth & normal dental arch
Secondary crowding:
(An acquired anomaly)
After
- Premature loss of deciduous
(1) mesial drifting of the posterior teeth (in the lateral
segment)
2) lingual or distal displacement of the anterior teeth
Tertiary crowding:
The etiopathogensis is under
debates
Occur mainly in the mandibular
anterior teeth during & after
adolescence
- Forward growth of mandible in conjunction with
soft tissue pressures
- Mesial migration of the posterior teeth.
- Erupting third molars

27. Tertiary crowding: (late incisor crowding is due to late mandibular growth)

28. This is caused &
associated with
skeletal, muscular or
functional occlusal
problems
This is due to disharmony b/w
the size of teeth & the space
available for them without
skeletal, muscular or
functional occlusal problems
Simple crowding
Complex crowding
Classification of Crowding

29. Severe malalignment
of all four incisor,
supporting zone
restricted
Crowding in mixed dentition:
Slight malalignment
of anterior teeth,
No abnormality in
supporting zone
First degree crowding Second degree crowding Third degree crowding
Pronounced malalignment
of anterior teeth,
No abnormality in
supporting zone

30. 1. Premature loss of primary tooth
2. Proximal caries leading to arch length discrepancy
3. Prolonged retention of primary tooth
4. Altered eruption sequence
5. Discrepancy in individual tooth size
6. Rotation of tooth
7. Ankylosed primary tooth
8. Trauma
9. Iatrogenic treatment
10. Abnormal shape of the tooth
11. Abnormal eruption path
12. Transposition of tooth
Aetiology of crowding
1. Tooth size – jaw size discrepancy
Hereditary crowding:Environmental Crowding

31.  Crowded mandibular incisor teeth
Premature exfoliation of the primary canine
 A midline displacement of the permanent
mandibular incisors on the crowded side
 Lateral incisors on the crowded side blocked out,
usually lingually but occasionally labially
 Crowded Maxillary incisor teeth
Clinical Features of Class I Crowding
 Class I molar

32.  Crowded mandibular incisor teeth
Premature exfoliation of the primary canine
 A midline displacement of the permanent
mandibular incisors on the crowded side
 Lateral incisors on the crowded side blocked out,
usually lingually but occasionally labially
 Crowded Maxillary incisor teeth
 Bulging of canines in the unerupted position

33.  Crowded mandibular incisor teeth
Premature exfoliation of the primary canine
 A midline displacement of the permanent
mandibular incisors on the crowded side
 Lateral incisors on the crowded side blocked out,
usually lingually but occasionally labially
 Crowded Maxillary incisor teeth
 A splaying out of the permanent
maxillary or mandibular incisor
teeth due to the crowded position of
the unerupted canines
 Bulging of canines in the unerupted position

34.  Crowded mandibular incisor teeth
Premature exfoliation of the primary canine
 A midline displacement of the permanent
mandibular incisors on the crowded side
 Lateral incisors on the crowded side blocked out,
usually lingually but occasionally labially
 Maxillary mandibular alveolodental
PROTRUSION without interproximal
spacing
 Crowded Maxillary incisor teeth
 A splaying out of the permanent
maxillary or mandibular incisor
teeth due to the crowded position of
the unerupted canines
 Gingival Recession on the labial surface of
the prominent mandibular incisor
 Bulging of canines in the unerupted position

35. Management of crowding
Investigations: Mixed dentition model analysis like Moyer’s is carried out to
find out the arch length discrepancy

36. uses 4 lower permanent incisors TO:
Predict the amount of crowding (or spacing) when 1st , 2nd premolars and canines erupt
Moyer’s analysis
Step1: Determine space available
- Determine teeth size (lower incisors)
- Use Moyer’s chart to get the total
teeth size for the unerupted
mandibular 1st,2nd premolars and
canine
Step 3: space analysis
Space available - space required = a negative # = space deficiency
Space available - space required = a positive # = excess space
Step2: Determine space required:

38. Age – After eruption of 21/12 Timing Treatment
Slight crowding–slight changes in the
position of anterior teeth
Wait and watch No treatment
Moderate crowding–lack of space by
width of one lateral incisor
Can wait till (OR)
premolar eruption
Expansion
Guidance of eruption
Pronounced crowding Immediate Treatment Serial extraction
Extraction &
orthodontic treatment
Crowding in mixed dentition : Therapy

39. Management of crowding in young adult

40.  Arch length analysis for permanent
dentition like Carey’s analysis should
be carried out
 Complete Kessling’s diagnostic set-up
should be carried out without
proclining incisors
Management of crowding in young Adult
Investigations:

41. Carey’s analysis
Crowding is determined by:
- Subtracting the total mesiodistal tooth mass present
from the amount of space available:

42. Degree of crowding=
the Permanent Dentition
space available= A+B_C+D
space required= total mesiodistal tooth mass
space required - space available

43. Treatment of crowding:
Stripping
Distallization
Expansion
Extraction
MILD or MODERATE
moderate to severe
Treatment depends on the severity
Analyze space
discrepancy using
model analysis.

44. - Treatment planning should be aimed at the choice of extraction
- After extraction, treatment is done with preferably fixed
appliance mechamotherapy
Extraction
Non-extraction
In cases with mild discrepancy, non-extraction method of treatment is followed
 Proximal reduction & treatment with either removable appliances or fixed appliance
 Lip bumpers are useful in increasing the arch length
 Arch expansion procedures also can be carried out to alleviate crowding
 Molar distalisation is another method to gain space in minor crowding correction
 Treatment can be either by non-extraction or extraction

45. Removable Appliances
- Mild Crowding
- Stripping then
- Removable Appliances
Contain:
Z-spring & Labial bow
Proximal reduction & treatment with either
Stripping: cutting 0.5mm from the tooth mesially
and distally but not more because then you’ll
enter the dentine.
To minimize the width of the teeth mesiodistally
fixed appliance

46. Lip bumpers
Relieve anterior crowding by DISTALIZATION of first permananet Molar

47. Arch expansion Mild – Moderate Crowding

48. Molar distalisation
Moving the teeth posteriorly
Mild – Moderate crowding

49. Extraction
Usually either 1st or 2nd premolars are
removed
- (this is not a rule ya3ni if the premolars
are sound but the 1st molar is grossly
carious and decayed then we will go for
extracting the molar instead of the sound
premolars)
Moderate – Severe crowding

50. What happen if we treat sever crowding
without extraction?

51. Spacing

52. Imperfections in teeth alignment & distance, wherein there is gap b/w two teeth or many teeth
Definition
Types of Spacing
LOCALIZED Spacing
A condition in which Spacing is present in localised regions or areas
(i) LOCALIZED Spacing (ii) GENERALIZED Spacing

53. Determined genetically
Caused by
(1) disproportionately
sized teeth & jaws
(2) tooth agenesis
Primary / hereditary spacing
An acquired anomaly
Caused by drifting of
teeth subsequent to loss
of permanent teeth
Secondary spacing
 caused by bone loss
due to periodontal
disease
Tertiary spacing:
Classification of Spacing

54. Close the space / maintain
Replace with an implant or bridge
Aetiology of localized spacing
a. Congenitally missing teeth
b. Unerupted teeth:
impacted/unerupted
c. Premature loss of
permanent teeth
1. Missing teeth
This results in:
(i) ectopic eruption of
permanent successor &
(ii) when the primary tooth is
exfoliated after ectopic
eruption of permanent
successor space results
2. Prolonged retention
of primary teeth
3. Sucking habits

56. 1. Arch length – tooth
material discrepancy
2. Macroglossia 3. Sucking habits 4. Abnormal
tongue posture
Micodontia Macrognathia
Best treated by :
- jacket crowns,
composite build-ups or
- consolidation of spaces
& placement of bridges
Small teeth in
normal jaws
Normal teeth in
large jaws
a. Best method of treatment:
Protract the Posterior Teeth to close
anterior spaces if the profile is acceptable
c. Other methods: jacket crowns, composite
build-ups or consolidation of spaces &
placement of bridges
GENERALIZED Spacing
The causes for Generalized spacing are:

57.  Conditions where spaces are
to be closed by protraction
of posterior teeth can be
achieved only by fixed
appliances mechanotherapy
Orthodontic Management
 Remove the cause
 can be closed with removable
appliances/ fixed appliance
 If there is proclination associated with
spacing. Hawley’s appliances are used
for closing space & retraction
 Retention: cases treated orthodontically usually required long-term retention
LOCALIZED Spacing Generalized spacing
 Prosthodontic management: some times localized spaces are best treated by:
Jacket crowns or composite build-ups

58.  Generalized spacing is usually due to a
jaw-size to teeth-size discrepancy.
treatment of generalized spacing :-
Usually with fixed appliance
retain with permanent retainer
bcz spacing tend to relapse
you need to

59. Median diastema
Is a form of localised spacing wherein there is a space
present b/w two central incisors
Causes of median diastema
Normal/developmental
1. Physiological
median diastema
2. Ethnic & familial
3. Imperfect fusion at
midline of premaxilla
Tooth material
discrepancy
1. Micodontia
2. Macrognathia
3. Missing lateral
4. Peg lateral
5. Extracted teeth
Physical impediment
1. Retained deciduous
2. Mesiodens
3. Enlarged labial frenum
4. Midline pathology
Habits
1. Thumb
sucking
2. Tongue
thrusting
Artificial
causes
RME

61. The possibility of space closure without treatment is inversely proportionate
to diastema size.
%Diastema in mm
991 mm
851.5 mm
501.85 mm
12.7 mm

62. Investigations
 Examine & confirm whether median diastema is
localized or part of generalized spacing
 Measure the mesiodistal width of the teeth
 BLANCH TEST:
 Periapical radiograph: (V-shaped notching b/w the
central incisors)

63.  Certain group of peoples, especially Negroid
exhibit median diastema as an ethnic norm
 Median diastema is seen in some families also
1. Physiological median diastema/ ugly duckling stage:
2. Ethnic & familial
 Spacing b/w central incisors is part of normal growth
 Self-corrected condition
3. Imperfect fusion at midline of premaxilla

64. Treatment of diastema :-
if there is mesiodense or
supernumerary you need to surgically
extract the supernumerary tooth.
{ with both of these cases we need
to do ortho to close the space }
1st ) We need to remove the cause >>
If there is frenal attachment
you need to do orthodontic &
frenectomy.

65. Orthodontic Management Median diastema
1. Closure by mesial tipping movements:
Appliances used are:
Removable appliance with two finger springs
Removable appliance with split labial bow
2. Closure by bodily movements:

66. if spacing results from proclination of incisors
3. Closure by reduction of overjet:
Hawley’s appliances / Robert's retractor
are used for closing space & retraction Fixed appliance

67. - Very small median diastema
– composite build-ups /Crown
4. Restorative management:
if you close the space then the appearance
of the teeth will be odd so the more
aesthetic option is to widen or enlarge them
to look better.

68. Class I malocclusionwith deep Bite: Class I malocclusionwith open Bite:
Class I malocclusionwith Crossbite:

69. growing patient Non-growing patient
Anterior Bite Plane
the overlapping of the upper anterior teeth over
the lowers in the vertical plane”.
Class I malocclusionwith deep Bite:

70. Class I malocclusion with Open Bite:
Growing patient
Non-growing patient
Fixed appliance with box elastics/ Surgery
- Eliminate habit: Thumb sucking/Tongue
thrust/Mouth breathing
- Growth modification
Frankel IV or chin cap with high pull headgear

71. Class I malocclusion with Crossbite
Malocclusion in which the mandibular teeth are in buccal version to the maxillary teeth
Anterior Cross bite:
Z-spring with posterior bite plane
Expansion screw with posterior bite
plane
Tongue blade Single tooth: Cross-elastics
Unilateral:
Unilateral expansion screw
Functional appliance
Bilateral:
Quad Helix Appliance
Coffin spring/ Expansion screw
Posterior Cross bite:

72.  IMPACTED or UNERUPTED TEETH.

73. Maxillary canine should be palpable in the buccal sulcus around
10 years old.
If not, investigate by taken radiograph.

74. Palatal: bucal= 85% : 15%
Unilateral : bilateral = 4:1
Female : Male = 70% : 30%
Impacted canines
Aetiology
Multifactorial:
- Long path eruption
- Earlier development than adjacent lateral
-Missing, small or anomalous adjacent lateral (
Guidance theory)
-Genetic theory, inheritance
Retained primary canines (Cs)

75. Auto transplantation
Impacted canines: Treatment options:
Pt. refuse ortho
trt & no pathology
Review with RGs
every 6 month
Pt. age= 10-13 Yrs
Ext. of primary canines
Pt. unwilling ortho trt
& there is pathology
Surgical exposure &
Orthodontic alignment
No treatment Interceptive
treatment
Surgical
extraction
‫راغب‬ ‫غير‬

76. Surgical exposure & Orthodontic alignment

77. Dr. Nabil Al-Zubair