Changing concepts of attritional occlusion (2)

Changing concepts of Attritional
occlusion
Dr.P.R.Begg
www.indiandentalacademy.com

Preview :
 Oldness of the idea regarding Attritional
occlusion.
 Stone age man’s dentition
 Characteristics of Attritional occlusion
 Correlative studies
 Relevance of Begg’s hypothesis to the
present day
 Present view regarding Attritional occlusion.

Oldness of the idea of attritional
occlusion.
 Sim Wallace (1904)
 Introduced the “disuse” idea.
 Efficient masticatory organ
 Importance of chewing
 Unnecessary blame on heredity
 Brain vs. osseous structures

Campbell T.D. (1925)
 Compared the quality and methods of
preparation of food b/w native and present
day aboriginals.
 Crude methods of preparation of food
required a very vigorous masticatory effort
which led to a very efficient and perfect
dentition.
 Dental diseases limited to individuals of
advanced years due to refinements in food.

Klatsky and Fisher (1953)
 Reintroduced the idea of SimWallace.
 Malocclusion – Disease of civilization.
 Re-examined 3 basic factors :
1. Heredity -- x
2. Environment -- x
3. Function -- √
 Undue importance on nutritional aspects of
diet rather than on food texture.

Stone age mans dentition
Dr.P.R.Begg (1954)
 Termed as Attritional occlusion
 Concept based on studies on Australian
aboriginals.
 Their teeth exhibited :
1. Extensive occlusal and interproximal wear.
2. Lack of caries, pdl disease, crowding.
 He considered the above as normal and
civilised man’s unworn dentition and
related problems as abnormal.

Anatomically correct occlusion
 Correct occlusion – Based on continual
change.
 2 important factors :
 Position of teeth in jaw bones.
- continual mesial migration and
vertical eruption which compensate for
tooth attrition.
 Anatomy of teeth.
- changing anatomy, dependent
upon attrition.

Stone age mans dentition
 When stone age man’s decidous incisors
erupt, his hard, coarse, fibrous, gritty food
immediately commences the process of
interproximal reduction and occlusal
attrition.
 Prerequisite – excess of tooth substance.
 As attrition occurs upper and lower
decidous incisors assume an edge to edge
overbite

 Decrease in the overall M-D length of the
deciduous dental arches.
 i.e. the permanent molars erupt further
mesially in the jaws than in civilized man.
 Begg’s view on Angle’s classification.

 As the permanent teeth erupt the process
of attrition is continous.
 Permanent incisors erupt in an overbite
similar to that of civilised man but soon
assume an edge to edge bite.
 i.e. lower incisors
- more prominent.
- curve of spee flat mesiodistally.

 Also , during the transition to an edge to
edge bite :
-- canines, premolars and 2nd
molars wear
interproximally and occlusally but maintain
contact by mesial migration.
-- provides adequate space for erupting
canines, 2nd
molars and 3rd
molars.

Begg (1930’s)
 Aim:
To evaluate the amount of reduction in size
of the lower dental arch prior to the
eruption of lower 3rd
molars.
 Measurements done on aboriginal skulls
collected from the south australian museum
using a boley guage in millimeters.
 Mandibles separated into 2 sets.

Results
 Difference b/w the 2 sets of measurements
-- 5.28 mm x 2 = 10.56 mm
 Maxilla : 1mm less than mandible.
 The above figure according to Begg is an
underestimation as canines, PM’s and 2nd
molars have just erupted
 with aid of “restoration” pencil drawing the
estimated reduction in arch width –14.7mm

Four degrees of tooth wear (Broca)
 First stage : enamel worn without
exposure of dentin
 Second stage : cusps worn down
and dentine exposed
 Third stage : appreciable amount of
crown worn away
 Fourth stage : wear extended to the
neck of the tooth

 Disagrees with :
-- Strang, Huckaba
-- Anthropologists
-- G.V.Black, E.H.Angle and others
 Concludes that textbook normal occlusion
develops only in those individuals who have
too small an amount of tooth substance.

Characteristics of attritional occlusion
( Evidence in favour of attritional occlusion )
 Edge to edge anterior overbite
 Gingival recession and vertical eruption
 Caries and periodontal disease
 Eruption of first permanent molars
 Anatomy of TMJ
 Proximal wear
 Eruption of 3rd molars
 Change in the curve of Wilson
 Reason for Cusps of Carabelli
 Secondary dentin and Pulpal pain
 Low incidence of malocclusions with tooth
crowding.

Edge to edge anterior overbite

Gingival recession and vertical eruption

Caries and periodontal disease

Eruption of first permanent molars

Anatomy of TMJ
 Shallow glenoid
fossa
 Low eminentia
articularis
 Flattened condylar
head
 Deep fossa
 Round condylar
head

Proximal wear

Eruption of 3rd molars

Change in the curve of Wilson
+ Reason for Cusps of Carabelli

Secondary dentin and Pulpal pain

X-Occlusion (M.J.Barret)

Variation of clinical procedures based
on the tenents of attritional occlusion
 Extractions are rational based on a sound
etiological basis as it simulates the
extensive M-D attrition in SAM.
 If tooth material excess is mild Ist PM
extraction suffices and if its grossly excess
8 teeth extractions are needed
 Opening of the bite to edge to edge position
in stage 1
 Retraction of upper incisors to edge to edge
position in stage 1
 Mesial movement of posterior teeth in
general in stage 2.

Evaluation of Australian aboriginals
(Corrucini et.al)
 Aim: To evaluate the Begg hypothesis.
 Method :A collection of dental casts from
the Yuendumu settlement situated 285km
northwest of Alice Springs in the northern
territory of Australia.
 Established in 1946 to provide a central
area for provisioning aboriginals who had
left their tribal areas

 Study consisted of 4 groups :
1. Older generation – born before 1937 (48)
2. Younger generation – post 1937 (48)
3. Aboriginal skulls – south aus.museum (48)
4. Haasts Bluff cast collection (35)

 Each occlusal variable was statistically
evaluated.
 The younger vs. older contrast was given
primary interest as it explained the effect of
civilization.

Results

 Summarized findings of Yuendumu study:
- No occluso-incisal attrition observed in
Yuendumu subjects.
- Leeway space could not be co-related to
crowding
- The overall size of teeth did not correlate to
crowding as the size of teeth of normal and
malocclusion subjects being identical.

Examination of dental crowding and its
relationship to tooth size and arch dimension
 Howe , Mcnamara
 To examine the extent to which tooth size
and jaw size contribute dental crowding.
 Conditions predispose crowding:
1. Excessively large teeth
2. Small bases
3. Combination

Materials and methods
 104 subjects – maxillary and mandibular
casts
 2 groups:
-- Non-crowded group
-- Crowded group
 Measurements :
- M-D tooth diameters
- Arch width
- Arch perimeter

 Conclusion
-- subjects with dental crowding were
more likely to have smaller dental arch
measurement than subjects without
crowding
-- treatment could be directed towards
1. Reduction of tooth mass
2. Dental arch expansion
3. Combination of both

Reassesment of Begg’s study
 2 studies done by Dawes, at university of
Adelaide in 1987 and other by Corrucini in
1990 showed a greater variance with the
results obtained by Begg.
 Studies on Attritional occlusion similar to
begg have not been able to relate with the
value of 10.56mm. Their estimate ranged
from 20-40% of begg’s value.
-- Murphy, Beyron 1964
-- Fishman 1976
-- Dawes 1987
-- Corrucini, Kaul 1990www.indiandentalacademy.com

 Dawes points a discrepancy b/w the
measurements of Campbell and Begg. If Begg
were to use Campbell's measurements the
value would have been 7.24 instead of 10.56.
 His measurements on skulls with and without
attrition were identical.
 Major evidence against Begg’s Hypothesis was
the longitudinal study on Yuendumu
aboriginals. Results were in contrast to the
cross-sectional approach of Begg.

Relevance of attritional occlusion to the present day
 Attrition does occur in SAM but certainly less
than 14.7 mm
 The role of diet, attrition and mesio-occlusal
migration are biologically valid explanations in
accounting for malocclusion.
 Mesio occlusal migration in modern man is
predicted on good tooth contacts and when a
loss of tooth occurs the teeth distal to the site
of loss move mesially.

Present day concept
 Etiology of malocclusion :
-- Attritional occlusion – X
-- Multifactorial
-- Corrucini view

 Extractions necessary but based on
analysis.
 Late lower incisor crowding
 Functional occlusion and incisal
guidance

References:
 Begg orthodontic theory and technique
-- Begg and kesling.
 Stone age man’s dentition
-- Dr.P.R.Begg :AJO 1954
 How anthropology informs the orthodontic
diagnosis of malocclusion’s causes
-- Robert S.Corruccini
 Contemporary orthodontics
-- W.Profitt
 www.cyberdontic.com/SlideFrm2.htm

Changing concepts of attritional occlusion (2)

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