Hypodontia Flashcards
hypodontia
congential abscnes of one or more teeth
anodontia
complete absence of teeth (none at all)
severe hypodontia
6 or more congenitally absent teeth
(excluding 8s)
describe
Missing lower central and upper lateral, retained lower \a
Pt likely bothered by diastema and missing upper laterals
prevalance of hypodontia
Prevalence approx. 6% (excl. 8’s)
* 6.3% F, 4.6% M in European population
0.9% primary dentition (less than permanent)
Most affected
* (8’s), L5’s, U2’s, U5’s, lower incisors
prevalance of missing upper lateral incisors
Approx. 20% of all missing teeth
Associated with ectopic canines
Most hypodontia cases will have missing U2’s
Greatest effect on aesthetics
* Most concerned
Often dealing with 2 problems at once (ectopic 3s and/or micro)
* Missing guiding root theory possible
prevalance vs incidence
Prevalence and incidence are different measures of a disease’s occurrence.
* “prevalence” of a condition means the number of people who currently have the condition, whereas “incidence” refers to the annual number of people who have a case of the condition.
A chronic incurable disease like diabetes can have a low incidence but high prevalence, because the prevalence is the cumulative sum of past year incidence rates.
A short-duration curable condition such as the common cold can have a high incidence but low prevalence, because many people get a cold each year, but few people actually have a cold at any given time (so prevalence is low and is not a very useful statistic).
aeriology of hypodontia can be either
3
non-syndromic
or
syndromic
or
environmental
non-syndromic aetiology of hypodontia
3
- Mutations in at least 3 genes associated with missing teeth in non-syndromic hypodontia
- Familial – quite common
- Sporadic a.k.a de novo
syndromic aetiology of hypodontia
examples
> 100 craniofacial syndromes assoc. with hypdontia
e.g.
Cleft lip and palate
Anhydrotic etodermal dysplasia
* ecto dermal tisues not develop fully
* Teeth are apart of this
environmental aetiology of hypodontia
not true hypodontia (as not developmental anomaly)
trauma or radio/chemotherapy
presentation options for hypodontia
4
- Delayed or asymmetric eruption
- Retained or infra-occluded deciduous teeth
- Absent deciduous tooth
- Tooth form
*No primary tooth guaranteed no permanent, As develop from primary tooth germ *
describe the tell tale signs of hypodontia in this case
4
Present early on, there’s tell tale signs
* Large midline diastema
* No lateral to stop the central drifting distally
* D infraoccluded absent successor
* Tooth from - tapered and small teeth hand in hand with hypodontia
10 associated dental problems with hypodontia
Microdontia
* Spacing caused by absence of permanent tooth exacerbated by small tooth
Malformation of other teeth
Short root anomaly
Impaction (common for upper 3s (or ectopic))
Delayed formation and/or delayed eruption other teeth
Crowding and/or malposition of other teeth
Maxillary canine/first premolar transposition
Taurodontism
* Enlarged pulp chambers
Enamel hypoplasia
Altered craniofacial growth
occlusion difficulty in hypodontia
often reduced vertical dimension and increased OB
making management challenging
potential orthodontic problems in hypodontia cases
5
spacing
drifting
over-eruption
aesthetic impairment
functional problems
hypodontia care pathway
GDP recognition
Referral to specialist orthodontist
In GDH
* Initial assessment in orthodontics and allocate when appropriate to Hyodontia Clinic (orthodontic and restorative input)
you are GDP and take this OPT
what should you do
common exam Q
refer to specialist as hypodontia case
with full radiographic report
tx for this hypodontia pt
4 stages
- Extraction URb, ULb (no2s)
- Sectional fixed appliance to close space between UR1, UL1 (midline diastema)
- Allows eruption UR3, UL3
Bonded retainers on back to prevent relapse
4 keys to successful management of hypodontia pts
- Inter-disciplinary team
- Joint assessment and treatment planning with precise aims
- Joint collaboration at transitional stages of treatment
- Follow up of treated cases
*How results last, not just when take off appliance
*
assessment and planning stages
7
History
Extra-oral examination
Intra-oral examination
* Orthodontic aspects
* Restorative aspects
Investigations
Problem list
Definitive Plan
Retention / maintenance
* How easy for pt to retain, longevity of restorative solutions
investigations for hypodontia pts
5
Study Models
Planning models
* Kesling, diagnostic
Radiographs
* OPT likely to account for all absent teeth, Root morph, neral dent health
Photographs
* see where you at and to compare
Conebeam CT
what can be an aid to ortho-restorative tx planning
diagnostic set up
tad =
temporary anchorage device
like a mini bone screw
IOTN 4h
absence of 1 tooth in a quadrant
IOTN 5h
absence of at least 2 teeth in 2 quadrants
pt concern re hypodontia
Dental health small impact
* caries, perio - if anything easier to clean
Reduction in tooth substance to chew - not really
Mainly don’t like gaps
tx options for missing upper lateral incisors
4
- accept
- restorative alone
- orthodontics alone
- combined orthodontics and restorative tx
examples of
Restorative-only solution to missing upper laterals
achieve partial closure of diastema
Supplemental premolar?
describe this case
Absent UR2, with shift of upper centreline, but low treatment need due to acceptable aesthetics and function
Likely complain cross over centrals, centre line to right
Likely not notice hypodontia
2 pathway options for combined orthodontic and restorative tx
missing upper lateral incisor
open space
close space
* simple
* space closure plus
restorative options after opening space with ortho for missing lateral incisor cases
5
*** RBB
* Implant **
* conventional bridgework
* autotransplantation
* partial denture
3 things about the tx plan of choice
- Satisfies expected aesthetic objectives
- Least invasive
- Satisfies expected functional objectives
* Immediate
* Long term (65 years+)
Informed consent needed for these aspects
pro of acrylic partial denture after opening space
good OH maintained as can remove and clean easily
describe tx here
Absent upper 5 with retained es
Resin-Bonded Bridges replacing absent upper lateral incisors.
Bonded retainer wire in place to prevent relapse of diastema
Lends to space opening rather than closure
Need upper fixed to redistribute space between central and 3- to make correct space for pros replace
Cantilever RBB and Bonded retainer wire to keep diastema close
role of TAD
keep posteriors in place whilst retracting canines
bridges in canine region
fail often due to occlusal force on them
what has happened here
labial rotation of lateral incisor cantilever pontics due to mesial replapse of canines (not wearing retainer)
cause displeasing appearance
what has happened here
labial rotation of lateral incisor cantilever pontics due to mesial replapse of canines (not wearing retainer)
cause displeasing appearance
RBB design for hypodonita
better success rate with cantilever design
ideal abutment is canine
technique sensitive
RBB for hypodontia adv
5
Relatively simple
Do when young (complete treatment) (unlike implants as vertical growth can occur till 20/21)
Non-destructive
Can look good
Place on semi-permanent basis
Can be until growth complete, or longer term
RBB disadv for hypodontia
3
Failure rate
* Bonding
* Chipping/prosthesis part
Appearance sometimes not good, (easy to try again, new materials)
Orthodontic retention needs are high (relapse risk)
space needed for implant
approx 7mm at gingival level
pt needs to wear retainer with tooth in it
describe tx needed here
Planned extraction of retained ULC to allow retraction of UL3 and space creation for prosthetic replacement of UL2.
*Canines next to upper central
C distal to it
Primary C extract, distalise 3 - challenge need anchorage right TAD
*
why need radiographs or CBCT for implants
confirm root separation
CBCT allows more accurate assessment of root positions, bone width and volume in implant planning
* gold standard
implants give the most predictable aesthetics??
no
- Recession of gingival margin on labial of implant, leaving metalwork visible
- Can be hard to fix metal work showing
Warn pt and inc in informed consent
* Complex
* Can be excellent
7 key differences between RBB and implant
- Can’t do implant till about 18-19 (or later?)
- Need minimum 7mm space
- Root separation!
- Often need bone graft
- Technically very demanding in aesthetic zone
- Significant extra time to do
- Significant cost
can be hard to achieve space
7 key differences between RBB and implant
- Can’t do implant till about 18-19 (or later?)
- Need minimum 7mm space
- Root separation!
- Often need bone graft
- Technically very demanding in aesthetic zone
- Significant extra time to do
- Significant cost
can be hard to achieve space
simple space closure
minimal invasive procedure after closure (e.g. small composute bondings)
when assessing for simple space closure assess
When deciding take into account these factors
* Tooth shape/size
* Tooth colour - canine can be more yellow than lateral
* Gingival architecture
Gingival margin levels of central incisor and canine need to be assessed when planning space closure approach
* normal is up down up (1, 2, 3)
so if Missing upper laterals without large amount of space to close
Favourable gingival margins - Canines below central incisor margin
3 ways to make a canine look like a lateral
- Individualised extrusion of canine re gingival contour height relative to U1 (gingiva follows tooth movement)
- Significant reshape U3 reshape low hanging cusp
- Bleaching U3 (tray for them only, also acts as a retainer - fits over bonded wire)
how to make a first premolar look like a canine
3
- Intrude U4 to give correct gingival architecture
- Rotate to take up more space
- Composite build up or veneer U4 to restore vertical height and ‘caninise’ the U4
3 adv of space closure plus
- No prosthesis – relatively low maintenance
- Good aesthetics with appropriate orthodontic and restorative techniques
- Can be done at an early age
autotransplantation
when upper 5 blocked out due to loss of E (space closed) can be autotransplanted into site of missing lateral - rare
what tx has this hypodontia pt had
space closure plus (build ups)
what tx has this hypodontia pt had
implants
what tx has this hypodontia pt had
RBB upper left lateral
successful management of hypodontia pt needs
4
- Inter-disciplinary team (joint appointment)
- Joint assessment and treatment planning with precise aims
- Joint collaboration at transitional stages of treatment
- Follow up of treated cases
