management of anomalies in tooth number

1. 1
Dr. Mohammed Alruby
Management of anomalies in tooth
numbers
Prepared by
Dr: Mohammed Alruby
‫الماء‬ ‫كثره‬ ‫من‬ ‫يموت‬ ‫فالورد‬ ‫حقهم‬ ‫من‬ ‫اكثر‬ ‫الناس‬ ‫تعطي‬ ‫ال‬

2. 2
Dr. Mohammed Alruby
Anomalies in number of teeth
One of the factors that lead to malocclusion:
1- Supernumerary teeth:
= Occurs most commonly in maxilla, sometimes these teeth is well formed so it is difficult to
determine which one are the extras
a- Supplemental: close to the original site, commonly seen in premolar or lateral
b- Mesiodens: occurs in midline palatal to maxillary central incisors, they are conical in
shape, occurs in pairs or single
= supernumerary teeth lead to delayed eruption or prevent eruption of permanent teeth as incisors
which may become cystic after time
2- Missing teeth:
Congenital missing teeth are more frequent than the supernumerary teeth
Common teeth missing frequency are:
- Third molars
- Maxillary lateral incisors
- Mandibular second premolars
- Mandibular incisors
- Maxillary second premolars
3- Early loss of permanent teeth:
May be due to trauma or caries of permanent dentition as in male patient with excessive overjet,
this patient is more liable to trauma, and 1st
molar permanent is commonly affected by caries
Treatment modalities of each case:
1- Supernumerary teeth:
Tooth or tooth like structure which develops in dentition to the normal
Incidence: 1-2 % 80% in maxillary anterior, 10% of midline diastema due to supernumerary
Etiology: division of tooth bud, hyperactive dental lamina, genetic influences
Types:
==Conical:
- Small peg shaped tooth
- Root usually well developed
- May be inverted
- In midline known as mesiodens
== tuberculate:
- No roots and remain unerupted
- Often in pairs
- Delayed or prevent eruption of central incisors
== supplemental:
- Resemble the crown morphology of adjacent tooth
- Most common in lower incisors or lateral maxillary
- Most commonly in primary dentition
- TTT: extraction is most appropriate one: always check root from radiograph

3. 3
Dr. Mohammed Alruby
== odontomes:
- Complex: diagnosed as round mass of dentine, pulp, and enamel
- Compound: mass of discrete denticles each containing dentine, pulp, and enamel
- 4 times more common than complex
Diagnosis: clinical investigation, and radiographs to localized teeth using parallax technique
Treatment: depend on type and position of supernumerary teeth for removal and monitoring
 Tuberculate one need to remove to allow eruption of teeth with maintaining of space
 Some cases recommend bracket attachment or only exposure of crown depend on position
of tooth and amount of root formed
 Surgical removal of supernumerary tooth prior to orthodontic treatment to avoid resorption
of permanent roots
 Follow all procedures for fixed appliances until good alignment is occur, for all teeth and
good occlusion
2- Missing teeth: hypodontia:
Dental anomalies associated with hypodontia:
- Generalized reduction in crown and root size
- Conical crown shape
- Enamel hypoplasia
- Delayed eruption
- Prolonged retention of primary teeth
- Infra-occlusion of primary teeth
- Tooth impaction
- Ectopic eruption – transposition
- Lack of alveolar bone
- Reduction of vertical dimension
- Increased overbite
Lateral incisors: 2% of population, with familial tendency for both peg shaped and missing
Associated with palatally ectopic canines
Premolars: lower 2nd
premolar: more frequent than upper
Treatment options:
- Open space
- Close space
- Distribute space
Advantages of space opening:
- Improved esthetics
- Good occlusion and intercuspation
- Little ability to close all spaces completely
Disadvantage: commits the patient to permanent prosthesis
Treatment mechanics for missing lateral:
1- Space opening:
Fixed appliance for tooth control, using push pull mechanics to open space, using open coil spring
and lace back to retract canine
Once appropriate space is opened use acrylic tooth to maintained the space
Use Hawley type of retainer incorporating prosthetic teeth and stops
Take in consideration the need long time of retention

4. 4
Dr. Mohammed Alruby
2- Space closing:
Invert canine bracket or bond bracket lateral to canine, this will:
- torque the canine root palatally
- reducing the canine eminence
- locate the canine root similar to the position that should have been occupied by lateral
canine extrusion to allow the gingiva to be positioned more incisally mimic that of lateral
may be need additional palatal root torque for canine
retention: bonded retainer.
Treatment mechanics for missing 2nd
premolars:
May be incorporated into extraction pattern if malocclusion have crowding
Maintain lower deciduous long term but reduce mesio-distal width and check root morphology
Congenitally missing tooth:
A tooth that not erupted in the oral cavity and not visible in the radiograph
Hypodontia: 1- 6 missing
Oligodontia: more than 6 missing
Anodontia: complete absence
Congenitally missing lateral incisors may be treated as follow:
1- canine substitution:
in which the occlusion is:
- class II with no crowding
- class I with sufficient crowding required lower extraction
- achieve proper overjet and overbite
in which profile is:
- straight profile is ideal
- Mild convex may be acceptable
Canine shape and color:
- Crown width evaluated at CEJ, narrow mesiodistal produce more esthetic than the wide
one
- Colored should match the centrals: ----- bleaching or veneer
- Crown with more convex labial surface need significant amount of reduction
- Narrow mid crown buccco-lingual is good
- Some cases may require Gingivectomy at the gingival margin
2- Tooth supported restoration:
How much space is necessary for missing lateral incisors?
a- Golden properties:
Should have ratio in anterior segment 1:6
If U1 is 8mm -------------- U2 is 5mm
b- Contralateral incisors
c- Bolton analysis
d- Diagnostic set up
 Resin bonded fixed partial denture: may land bridge
The optimal esthetic depends on:
- Position of abutment teeth
- Thickness of abutment teeth

5. 5
Dr. Mohammed Alruby
- Mobility of abutment teeth
- Over all occlusion
- Translucency of abutment teeth
 Cantilever fixed partial denture
 Conventional full coverage fixed
3- Implant for single tooth
3-Loss of permanent teeth:
A- Early loss of 1st
permanent molars:
If 1st
permanent molars are removed before age of 8 years, there is some complications:
- There is no evidence about third molar development
- Unerupted mandibular second premolar can drift distally and tip from its position below
the apices of primary second molar
- Lower labial segment can retroclined, resulting in an increased overbite
- Maxillary second molar will often erupt into good position, but space loss can be rapid
Treatment planning:
** in class I malocclusion:
1- Minimal to moderate crowding: extraction at time which allow eruption of 2nd
molar and
relief of crowding at same time
2- Sever crowding: delayed extraction until eruption of 2nd
molars and use extraction space
for tooth alignment with fixed appliance
3- With lower 1st
molar extraction considers compensatory extraction in upper
** in class II division 1 malocclusion:
1- Time of upper 1st
molar extraction is important because the need to reduce overjet. For
extraction of lower 1st
molars, compensatory extraction of upper or using holding appliance
as URA or TPA to prevent upper molar extrusion (over eruption)
2- Extraction of upper 1st
molar and start process to relief crowding and correction of sagittal
discrepancy
3- Extraction of 1st
molar upper and wait for second molar to erupt then treated by functional
appliances or molar distalization or premolar extraction with fixed appliances- but in case
of 1st
premolar extraction, the third molars should ideally be present and in good
morphology
4- Extraction of upper 1st
molar after second molar eruption and use the space for overjet
correction with fixed appliances
** class II division 2 malocclusion:
Similar to class II division 1 except for overbite reduction can be difficult if there is large extraction
space
** class III malocclusion:
Used space of extraction to relieve crowding and incisors retraction in mandible and this provided
by extraction after second molar erupted
N: B:
The best occlusal results obtained in the following cases:
1- Child aged around 4 years
2- All permanent teeth including third molar are present
3- There is class I occlusion
4- Minimal or moderate buccal segment crowding

6. 6
Dr. Mohammed Alruby
5- Mandibular second molar roots should be approximately half formed with evidence dentine
calcification within bifurcation
N: B:
Balancing extraction: extraction on other side
Compensatory extraction: extraction on opposite arch
B- Early loss of maxillary central incisor:
= Traumatic loss of maxillary central incisor is seen in around 3% of children
= It occurs unilateral in mixed dentition of boys with increased overjet
= Long term space maintainer can be achieved with partial denture however this can be associated
with loss of alveolar bone height
OR: the space can be allowed to close and respond in the permanent dentition prior to prosthetic
replacement, this allows preservation of alveolar bone, but will required fixed appliance treatment
and often space creation in upper arch
= in case of bilateral loss of central incisor, moving lateral to posterior position of central and
modify their coronal morphology to obtain good esthetics