Dental Public Health Al Azhar University Gaza Lama k El Banna

2. College of Dentistry
Dental Public Health
Dental Caries Factors
Dr. Hazem El Ajrami
Master Degree in Orthodontic & PedodonticMaster Degree in Orthodontic & Pedodontic

3. D. Inheritance:
There is a wide spread clinical impression
that dental caries varies considerably from
family to family, and that inheritance of a
characteristic tooth structure or form either
good or poor is common. Good genetic
studies of caries incidence are few in number
and in such studies it is difficult to
distinguish between true inheritance through
the chromosomes and the dietary and other
habits in the family.

4. E.Emotional disturbance:
There is a wide spread clinical impression
that emotional disturbances, particularly
transitory anxiety states, influence the incidence
of dental caries, such statement is difficult to
document because of the difficulties of defining
stress and of relating it accurately to a chronic
disease such as caries.

5. One study is available on dental caries,
attempting to relate dental examinations in terms
of DMF teeth to mental diagnosis among
psychiatric patients. Statistical analysis
demonstrated a higher dental caries experience at
all ages among the manic depressive group than
in the base line hospital population.
Another study involving 661 patients, reported
close correlation between severe mental stress
and dental caries.

6. F. Nutrition:
Nutrition can be called a host factor to the
extent that individual instinctively
selects specific foods from the array
available to him. Health education, directing
a choice among foods, is an environmental
factor.

7. G. Variation of caries within the mouth:
Observation on the variation of caries
within the mouth could be grouped under
three main headings:
1) Observations on types of caries according
to tooth surfaces attacked.
2) Observations upon frequency with which
the different teeth in the mouth are
attacked.
3) Observation upon bilateral symmetry.

8. 1) According to tooth surfaces:
 Pit and fissure caries.
 Proximal caries.
 Cervical caries.
 Root caries.
2) Variation in point of attack: lower incisors are the
least teeth exposed to caries.
3) Bilateral symmetry.

11. 2. Agent Factors:
I. Bacterial factors.
II. Role of carbohydrates.

12. I. Bacterial factors:
Since the days of Miller, dental caries
research has been directed toward the
identification of a microbial agent for the
disease. At first, many workers, have drawn
the attention to the relation which appeared to
exist between dental caries rate and the
number of lactobacilli, in the mouth.
Attention now centers on various groups of
streptococci.

13.  The potential of certain strains of
streptococci to induce plaque and multi-
surface cavitation has been conclusively
established in animals and strongly
implicated in humans.
 Mainly streptococci for initiation of dental
caries and lactobacilli for propagation.

14. II. Role of carbohydrates:
 Freely fermentable carbohydrates have an
essential role in caries process.
 Not all carbohydrates are equally
conductive to plaque formation and multi-
surface caries. The rate of clearance from
the mouth also affects the rate by which
bacteria may act upon carbohydrates to
produce acids.
 Carbohydrates with rapid oral clearance
seem to be less dangerous than those which
remain in the mouth for a long time.

15. 3. Environmental Factors:
I. Geographic variation:
A. Sunshine.
B. Temperature.
C. Relative humidity.
D. Rain fall.
II. Fluoride.
III. Total water hardness.
IV. Trace elements.
V. Degree of urbanization.
VI. Social factors.

16. I. Geographic variations:
So many detailed environmental factors are
dependent in one way or another on the
geography. In order to study geographic
variations in dental diseases apart from racial
or ethnic variations, it is necessary to select an
area for study inhabited either by one racial or
ethnic group predominantly or by such a
mixture of ethnic groups even out in large
samples.

17.  In studies performed in the United States,
the occurrence of dental disease suggests
two striking associations: latitude, distance
from seacoast this is mainly due to
climatological factors including sunshine,
rainfall, temperature and humidity.

18. A.Sunshine:
Is one of the factors most commonly thought
to vary with latitude. In one study in U.S.A.,
there was an inverse relation between the mean
annual sunshine and dental caries expressed as
DMF. The reason for this relation is that as the
annual sunshine increase the amount of
ultraviolet rays increases which insure enough
supply of vit. D. The effect of vit. D on the
formation of calcified tissue is well known.

20. Also in many areas of the world the temperature
is in direct relation with sunshine and as
sunshine increases temperature increases and
there will be increased demand for water
consumption. The increased water intake will
help wash away food debris from the mouth.

21. B. Temperature:
Varies almost entirely with latitude.
Temperature in turn, acts to vary the caloric
requirements and water intake of human beings.
Since carbohydrate food is a quick and cheap
source of caloric energy, so in localities of low
temperature, the carbohydrate consumption
specially sweets is high and there is a decrease
in water intake and therefore caries incidence
increases. The reverse occurs in localities of
high temperature.

22. C. Relative humidity:
It is the ratio of the amount of moisture in the
atmosphere to the maximum amount that can
occur without precipitation at a given
temperature and barometric pressure. Data
from some studies in Australia and U.S.A.
proved a higher correlation between DMF, and
relative humidity, as relative humidity rises,
the DMF rises too. This is because of
decreased demand of water intake in areas with
high humidity levels.

23. D. Rainfall:
Most of the crops utilize in their growth the
upper thirty centimeters of the soil, as the
rainfall increases leaching of the minerals
specially fluorides will lead to reduction of
fluoride concentration in the crops. Another
factor to be considered is that rainfall is
accompanied by heavy clouds which block
sunlight.

25. II. Fluoride:
 Especially fluoride in the communal water
supplies affects to a great extent the DMF
index.
 Fluoride can be considered an essential
element for the formation of caries-resistant
dental hard tissue. Fluoride in the drinking
water during the time of tooth formation
and mineralization results in formation of
fluoroapatite crystallites, which are more
caries - resistant.

26. III. Total water hardness:
Usually measured in terms of calcium
carbonate, is an etiologic factor in dental
caries. Some authors have reported an
inverse relation between DMF and the total
water hardness.

27. IV. Trace elements:
A number of trace elements deserve
attention, some are found in water supplies but
most are found in greater concentration in
common food-stuffs. It has been found that
there is marked increase in dental caries in
areas where selenium was high both in water
and food-stuffs. On the other hand,
molybdenum and vanadium have caries
inhibiting influences.

28. V. Degree of urbanization:
Urbanization may be accompanied by an
increase in dental caries. This may be due
to the type of diet in urban areas.
VI. Social factors:
Good economic status and social pressure
in the direction of good mouth appearance
are both strong factors in creating demand
of dental treatment.

29. Indices Used For Assessment of Gingival
and Periodontal Diseases

30. • Periodontal Diseases:
Periodontal diseases are inflammatory
conditions affecting the periodontium. The
periodontium comprises the gingiva, the
periodontal ligament, the alveolar bone and the
cement covering the roots of the teeth.

32.  Indices Used For Assessment of Gingival
and Periodontal Diseases:
1. P.M.A. Index.
2. The gingival Index (GI).
3. The Periodontal Index (PI) Russel's Index.
4. The oral hygiene index (OHI) and the oral
hygiene index simplified (OHI-S).
5. Community Periodontal Index of Treatment
Need (CPITN).

33. 1. P.M.A. Index:
Is the first successful attempt to design a
numerical system of recording gingival
conditions. The three letters stand for gingival
papilla mesial to the tooth, i.e. papillary (P),
marginal (M) and attached gingiva (A). From
clinical experience it was postulated that
periodontal disease starts from the interdental
papilla (P), spreads to the marginal area (M)
and continues to the attached gingiva (A).

35. • Thus all the present teeth are examined
(sometimes this index would be confined to an
area or quadrant). The number of the affected
P.M.A. units are counted, and considered as
separate estimates. Cases are called "mild" if 1
to 4 papillae and 0 to 2 margins are affected,
"moderate" if 4 to 8 papillae and 2 to 4
margins are affected, "severe" if more than 8
papillae and more than 4 margins are affected.

36. • Involvement of attachments is associated with
severe cases. The average P.M.A. for the
group is determined by totaling the number of
gingival units affected and dividing by the
number of cases under study.

37. 2. The Gingival Index (GI):
 The index is developed by Loe and Sillness.
The severity of the gingival condition is
indicated on a scale running from 0-3:
 0: No inflammation.
 1: Mild inflammation, slight redness, slight
edema, probing with a blunt probe do not
result in bleeding.
 2: Moderate inflammation: edema, redness,
glazing, the marginal gingiva is swollen,
probing with a blunt probe elicits bleeding.

38. Gingival EdemaGingival Edema

41.  3: Severe inflammation: marked redness
and edema, spontaneous bleeding and/or
ulceration.
 It is a partial recording system; six teeth are
selected for the examination:
6 2 4
4 2 6

42. • For each of the six teeth, mesial, distal, buccal
and lingual gingival unit is scored
independently. The tooth scores are summed
and divided by 4 gives the gingival index of the
tooth. The scores of the 6 teeth are summed and
divided by their number, given the GI of the
individual.

43. 3. The Periodontal Index (PI) Russel’s Index:
The criteria of the PI index are:
 0: Negative: There is neither obvious
inflammation in the investing tissue nor loss
of function.
 1: Mild gingivitis: There is an obvious area
of inflammation in the free gingiva, but this
area does not circumscribe the tooth.
 2: Gingivitis: inflammation completely
circumscribes the tooth but there is no
apparent break in the epithelial attachment.

44. 6: Gingivitis with pocket formation: The
epithelial attachment has been broken, and
there is pocket. There is no interference with
normal masticatory function, the tooth is firm
in its socket.
8: Advanced destruction with loss of
masticatory function, the tooth may be loose,
may have drifted, may have dull sound on
percussion, may be depressive in its socket.

49. • The data of PI is computed by examining all
the present teeth. The teeth scores are summed
and divided by their number; this will give the
PI of the individual. PI of a group equals to the
summation of the PI scores of the individuals
in the group divided by their number.

50. • The author writes 6 after 2 since:
If the PI score of an individual is small (i.e. 1
or 2) this indicates that this individual has
gingival affection but if it is high (6-8), this
indicates that this individual has only
periodontally affected teeth.
If the score is in between 2 and 6, this
indicates that this individual is affected by
both gingival and periodontal disease. This
index is most suitable for assessment of the
gingival and periodontal condition in adult
populations.

51. • Lilienthal et al. (1964) modified Russel’s
classification of periodontal condition using
partial recording system to be easier with
large surveys. The teeth used are:
• Here the authors take 7 instead of 6 due to the
frequent loss of the latter due to caries.
7 1 4
4 1 7

52. 4. The oral hygiene index (OHI) and the oral
hygiene index simplified (OHI-S):
These indices were first developed by
Greene and Vermillion 1964. The criteria used
to assign the scores to the tooth surface in the
OHI-S are the same as those used for the OHI.
The OHI-S and the OHI have two
components, the debris index and the calculus
index. Each of these indices, in turn, is based
on numerical determinations representing the
amount of debris and calculus formed on the
selected surfaces.

53. • For the OHI:
Each jaw is divided into 3 segments molar,
premolar and anterior segment, i.e. the canines
and incisors. After examination of the whole
mouth, the worst tooth in each segment is
taken as representative of the segment. The
buccal and lingual surfaces of each tooth are
scored. Therefore, the OHI comprises 12
surfaces of six teeth.

55. • For the OHI-S:
The examination is limited to 6 permanent
tooth surfaces. The labial surface of the upper
right central incisor, the labial surface of the
lower left central incisors, the buccal surfaces
of the upper first permanent molars and the
lingual surfaces of the lower first permanent
molars. When any of these teeth are missing, a
comparable adjacent tooth is substituted. Only
fully erupted teeth are scored.

56. 6 1 6
6 1 6

57. A. Oral Debris DI:
 0: No debris or extrinsic stain.
 1: Soft debris covering not more than one-
third of the tooth surface, or extrinsic stain
without debris regardless of the surface area
covered.
 2: Soft debris covering more than one-third
but not more than two-thirds of the exposed
tooth surface.
 3: Soft debris covering more than two-
thirds of the exposed tooth surface.

58. DI
Measurement of debris indices

59. B. Oral calculus CI:
 0: No calculus present.
 1: Supra-gingival calculus covering not more
than one third of the exposed tooth surface.
 2: Supra-gingival calculus covering more than
one third but not more than two thirds of the
exposed tooth surface or individual flecks of
subgingival calculus around the cervical
portion of the tooth.
 3: Supra-gingival calculus covering more than
two thirds of the exposed tooth surface or a
continuous heavy band of subgingival
calculus around the cervical area of the tooth.

60. Measurement of calculus indices
CI
0 1 2 3

61. Supra-gingival Calculus

62. Subgingival Calculus

63. • For determining OHI:
The mean of DI and CI of the examined 12
surfaces is computed and then we sum DI and
CI, i.e. DI equals the summation of the DI
scores of the 12 surfaces examined divided by
12 and also CI equals the summation of the CI
scores of the 12 surfaces examined divided by
12.
So, OHI = DI + CI

64. • For determining OHI-S:
The mean of DI and CI of the examined 6
surfaces is computed and then we sum DI and
CI. etc.