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POSTMENOPAUSAL OSTEOPOROSIS
during the hospital stay, can adversely influence
their clinical outcome
14
. An oral protein supple-
ment that brought the intake from low to a level
still below the recommended dietary allowance
(RDA) (i.e. 0.8 g/kg body weight), thus avoiding
the risk of an excess of dietary protein, improved
the clinical course in the rehabilitation hospital,
significantly lowering the rate of complications
such as bed-sores, severe anemia or intercurrent
lung or renal infections. The total length of stay
in the orthopedic ward and rehabilitation hospi-
tal was significantly shorter by 25% in supple-
mented patients than in controls
14–16
. Normal-
ization of protein intake, independent of that of
energy, calcium and vitamin D, was in fact
responsible for this more favorable outcome
15,16
.
Vitamin K and osteoporosis
A low level of vitamin K
1
and K
2
has been
reported in patients sustaining hip fracture
17
. The
degree of vitamin K deficiency in humans can be
assessed by measuring the undercarboxylated
fraction of osteocalcin. This fraction increases
with age and, therefore, is negatively related to
BMD in elderly women. Hence, undercarboxy-
lated osteocalcin has been found to be a predictor
of hip fracture. Energy–protein undernutrition is
usually associated with various vitamin deficien-
cies. To what extent vitamin K deficiency per se
contributes to bone loss in undernourished
patients sustaining hip fracture is still not known.
Other nutrients
By interfering with both the production and the
action of parathyroid hormone, magnesium may
indirectly affect bone metabolism. However, a
specific role in the maintenance of bone mass
during adulthood has not yet been identified.
Several trace elements are required for normal
bone metabolism. Various animal and/or ecolog-
ical human studies suggest that aluminum, zinc,
manganese, copper, boron, silicon and fluoride,
at doses lower than those used in the treatment
of osteoporosis, and vitamins B
6
, B
12
and C,
could play a positive role in the normal metabo-
lism of bone tissue. Selective intervention studies
are still required to delineate their respective
roles in the maintenance of bone mass, particu-
larly in the elderly.
Mechanical causes of bone mass loss
Immobilization is an important cause of bone
loss. The effect of disuse on bone mass is far
greater than that of adding walking to an already
ambulatory subject. Enforced immobilization in
healthy volunteers results in a decrease in bone
mineral mass. Motor deficit due to neurological
disorders such as hemiplegia or paraplegia is a
cause of bone loss. At the tissue level, immobi-
lization results in negative balance, the amount
of bone resorbed being greater than that formed.
At the cellular level, immobilization results in
increased osteoclastic resorption associated with
a decrease in osteoblastic formation. The nature
of the molecular signal(s) perceiving the reduced
mechanical strain has not yet been clearly identi-
fied.
To xic causes of bone mass loss
Excessive alcohol consumption appears to be a
significant risk factor for osteoporosis, particu-
larly in men
18
. Reduced rates of bone formation
have been associated with alcohol abuse. A high
intake of alcohol is often associated with marked
dietary disturbance such as low protein intake,
other changes in life-style, liver disease and
decrease in testosterone production. These alter-
ations can contribute to the osteoporosis
observed in heavy drinkers. The use of tobacco
appears to be associated with an increased risk of
both axial and appendicular osteoporotic frac-
tures in women and men
19
. This risk emerges
with age. Smoking reduces the protective effects
of obesity and of estrogen exposure. A reduced
rate of bone formation and increased bone
resorption might be responsible for bone loss,
through a reduction in the production of and an
acceleration in the degradation of estrogens.
GENERAL MANAGEMENT
The general measures to apply to reverse the
negative impact of life-style disorders (Table 3)
are based on the following reasons.
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There is a high prevalence of calcium, protein
and vitamin D insufficiency in the elderly
6,9
. Cal-
cium and vitamin D supplements decrease sec-
ondary hyperparathyroidism and, particularly in
elderly subjects living in nursing-homes, reduce
the risk of proximal femur fracture
20
. Sufficient
protein intakes are necessary for homeostasis of
the musculoskeletal system, but also in decreas-
ing the complications occurring after an osteo-
porotic fracture
8,10,15
. Under these conditions,
intakes of at least 1000 mg/day of calcium,
800 IU of vitamin D and 1 g/kg body weight of
protein can be recommended in the general man-
agement of patients with osteoporosis. Regular
physical exercise helps to maintain bone health,
not only by stimulating bone formation and by
retarding bone resorption, but also through a
favorable influence on muscle function
21,22
.
These measures, together with correction of
decreased visual acuity, a reduction of drug con-
sumption altering awareness and balance, and an
improvement of the home environment (slippery
floor, obstacles, insufficient lighting), are impor-
tant steps aimed at preventing falls
4,23
. However,
they have not been verified in randomized con-
trolled trials fulfilling the requirements of evi-
dence-based medicine. The wearing of hip pro-
tectors can significantly and specifically reduce
hip fracture risk
24
. This has been shown in ran-
domized controlled trials, and seems to be par-
ticularly efficient in the elderly living in nursing-
homes. This population is at very high risk, since
close to 40% of hip fractures occur in this kind of
setting
3
.
ACKNOWLEDGMENTS
Studies by our group cited in this chapter were
supported by the Swiss National Science Founda-
tion (grant nos. 32-49757.96, 32-58880.99 and
3200B0-100714). We would like to thank Mar-
ianne Perez for secretarial assistance.
75
Table 3 General management
Treat any disease causing bone loss
Ensure dietary calcium intake ≥ 1000 mg/day
Ensure adequate dietary protein intake (1 g/kg body
weight)
Correct or prevent vitamin D insufficiency
(800 IU/day)
Promote weight-bearing physical exercise
Reduce falling risk
Reduce fall consequences (hip protectors)
INFLUENCE OF LIFE-STYLE ON OSTEOPOROSIS
References
1. Cummings SR, Melton LJ. Epidemiology and
outcomes of osteoporotic fractures. Lancet 2002;
359: 1761–7
2. Chevalley T, Hermann FR, Delmi M, et al. Eval-
uation of the age-adjusted incidence of hip frac-
tures between urban and rural areas: the differ-
ence is not related to the prevalence of
institutions for the elderly. Osteoporos Int 2002;
13: 113–18
3. Schurch MA, Rizzoli R, Mermillod B, et al. A
prospective study on socioeconomic aspects of
fracture of the proximal femur. J Bone Miner Res
1996; 11: 1935–42
4. Myers AH, Young Y, Langlois JA. Prevention of
falls in the elderly. Bone 1996; 18: 87S–101S
5. Kanis JA. Diagnosis of osteoporosis and assess-
ment of fracture risk. Lancet 2002; 359: 1929–36
6. Seeman E. Pathogenesis of bone fragility in
women and men. Lancet 2002; 359: 1841–50
7. Heaney RP. Calcium, dairy products and osteo-
porosis. J Am Coll Nutr 2000; 19: 83–99S
8. Rizzoli R, Bonjour JP. Nutritional approaches to
healing fractures in the elderly. In Rosen CJ,
Glowacki J, Bilezikian JP, eds. The Aging Skeleton.
San Diego, CA: Academic Press, 1999: 399–409
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POSTMENOPAUSAL OSTEOPOROSIS
9. Rizzoli R, Ammann P, Chevalley T, et al. Protein
intake and bone disorders in the elderly. Joint Bone
Spine 2001; 68: 383–92
10. Rizzoli R, Ammann P, Chevalley T, et al. Dietary
protein intakes and bone strength. In Burckhardt
P, Dawson-Hughes B, Heaney RP, eds. Nutri-
tional Aspects of Osteoporosis. San Diego, CA: Else-
vier Academic Press, 2004; 379–97
11. Munger RG, Cerhan JR, Chiu BC. Prospective
study of dietary protein intake and risk of hip
fracture in postmenopausal women. Am J Clin
Nutr 1999; 69: 147–52
12. Dawson-Hughes B, Harris SS. Calcium intake
influences the association of protein intake with
rates of bone loss in elderly men and women. Am
J Clin Nutr 2002; 75: 773–9
13. Hannan MT, Tucker KL, Dawson-Hughes B, et
al. Effect of dietary protein on bone loss in elderly
men and women: the Framingham Osteoporosis
Study. J Bone Miner Res 2000; 15: 2504–12
14. Delmi M, Rapin CH, Bengoa JM, et al. Dietary
supplementation in elderly patients with frac-
tured neck of the femur. Lancet 1990; 335:
1013–16
15. Schurch MA, Rizzoli R, Slosman D, et al. Protein
supplements increase serum insulin-like growth
factor-I levels and attenuate proximal femur bone
loss in patients with recent hip fracture. A ran-
domized, double-blind, placebo-controlled trial.
Ann Intern Med 1998; 128: 801–9
16. Tkatch L, Rapin CH, Rizzoli R, et al. Benefits of
oral protein supplementation in elderly patients
with fracture of the proximal femur. J Am Coll
Nutr 1992; 11: 519–25
17. Booth SL, Broe KE, Gagnon DR, et al. Vitamin
K intake and bone mineral density in women and
men. Am J Clin Nutr 2003; 77: 512–16
18. Kanis JA, Borgstrom F, De Laet C, et al. Assess-
ment of fracture risk. Osteoporos Int 2005; 16:
581–9
19. Kanis JA, Johnell O, Oden A, et al. Smoking and
fracture risk: a meta-analysis. Osteoporos Int 2005;
16: 155–62
20. Chapuy MC, Arlot ME, Duboeuf F, et al. Vitamin
D3 and calcium to prevent hip fractures in eld-
erly women. N Engl J Med 1992; 327: 1637–42
21. Kelley GA, Kelley KS, Tran ZV. Exercise and
bone mineral density in men: a meta-analysis. J
Appl Physiol 2000; 88: 1730–6
22. Wolff I, van Croonenborg JJ, Kemper HC, et al.
The effect of exercise training programs on bone
mass: a meta-analysis of published controlled tri-
als in pre- and postmenopausal women. Osteoporos
Int 1999; 9: 1–12
23. Tinetti ME. Clinical practice. Preventing falls in
elderly persons. N Engl J Med 2003; 348: 42–9
24. Kannus P, Parkkari J, Niemi S, et al. Prevention
of hip fracture in elderly people with use of a hip
protector. N Engl J Med 2000; 343: 1506–13
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Postmenopausal osteoporosis and dental
health
J. Wactawski-Wende
10
INTRODUCTION
Osteoporosis and periodontitis are diseases that
affect a large number of men and women in the
United States and worldwide, with increasing
incidence with advancing age. Osteoporosis is a
skeletal disorder characterized by compromised
bone strength predisposing to increased risk of
fracture, with bone strength determined by both
bone density and bone quality
1
. Periodontitis has
historically been described as an infection-
mediated process characterized by resorption of
the alveolar bone as well as loss of the soft tissue
attachment to the tooth, and is a major cause of
tooth loss in adults. It is assessed by oral exami-
nation, and typically characterized by determin-
ing the amount of loss of clinical attachment of
the soft tissue adjacent to the teeth and the
depth of pocket between the tooth and gum, or
by measuring loss of alveolar crestal bone height
(ACH) surrounding the teeth.
Periodontal disease is a major cause of tooth
loss and edentulousness in adults
2
, and has been
associated with a number of chronic diseases
3–5
including osteoporosis. The association between
osteoporosis and both periodontal disease and
tooth loss in postmenopausal women has been
addressed in a growing number of studies.
OVERVIEW OF PERIODONTAL
DISEASES
Periodontal diseases include both gingivitis and
periodontitis, which are infection-mediated
inflammatory processes in the oral cavity. Both
gingivitis and periodontitis are common in
adults. Gingivitis usually affects only the gums
and can result in inflammation, whereas peri-
odontitis is usually more extensive, involving
more of the soft tissue and the alveolar bone sur-
rounding the teeth. Although milder forms of
periodontitis are more common, the percentage
of individuals with moderate to severe periodon-
titis increases with age. The more severe forms of
periodontitis lead to the destruction of support-
ing tissue and resorption of the alveolar bone sur-
rounding the teeth, and can, in the most severe
cases, lead to tooth loss.
Although gingivitis may never proceed to
periodontitis, it is usually the precursor to this
more severe form of disease. Gingival inflamma-
tion is chararacterized by swelling, bleeding and
reddening of the gums, which can be tender.
Bacteria accumulate in the biofilm (plaque) at
the gingival margins and result in a local
immune response. Dental hygiene including
brushing, flossing and cleaning, which reduce
plaque formation, can reverse this process. How-
ever, gingivitis can lead to chronic infection and
periodontitis in those instances where the
amount of plaque and infection are left un-
checked. The infectious agents that lead to
destructive periodontal disease are typically
gram-negative anaerobes. Factors that can influ-
ence gingival inflammation include sex steroid
hormone levels, certain medications, cigarette
smoking and certain diseases (human immuno-
deficiency virus, HIV). Most forms of adult peri-
odontitis are moderately progressive and respon-
sive to treatment.
In a healthy mouth, teeth are well supported
by surrounding soft tissue and bone. The perio-
dontal membrane or ligament attaches the sur-
rounding soft tissue to the cementum of the
tooth. Bony structure surrounds the tooth and
77
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provides support (Figure 1). In general, a chronic
oral infection results in an immune response and
gradual loss of attachment of the periodontal lig-
ament to the gingiva. In addition, there is a loss
of bone supporting the teeth. In the case of
periodontitis, there is an accumulation of subgin-
gival plaque. If the plaque is untreated, it
becomes hardened, and this substance is known
as calculus or tartar. As the condition progresses,
the infectious agents in the biofilm continue to
produce toxins that eventually destroy the peri-
odontal ligament and bone, which over time
results in the formation of a pocket between the
tooth and adjacent tissues. This pocket harbors
subgingival plaque and calculus and continues to
cause damage to the surrounding tissues. If not
treated, the disease progresses further until so
much soft tissue and bone are lost that the tooth
becomes unstable and can in some instances be
lost. The progression of periodontal disease is
illustrated in Figure 2.
The extent and severity of periodontal disease
are determined through a series of measure-
ments, including assessing the extent of gingival
inflammation and bleeding, the probing depth of
the pocket to the point of resistance, the clinical
attachment loss of the periodontal ligament
measured from a fixed point on the tooth (usu-
ally the cemento–enamel junction) and the loss
of adjacent alveolar bone as measured by X-ray
3
.
Tooth loss due to periodontal disease can also be
used to describe the extent and severity of dis-
ease. Severity is determined by both the extent of
disease at any point in time and also the rate of
disease progression over time and response of the
tissues to treatment.
Gram-negative bacterial agents that have
been implicated in the occurrence of periodontal
disease include Porphyromonas gingivalis, Prevotella
intermedia, Tannerella forsythensis (Bacteroides
forsythus), Treponema denticola and Actinobacillus
actinomycetemcomitans
3,6–9
. In reaction to the infec-
tion, neutrophils and antibodies respond to the
site of the attack. In addition, cytokines and
prostaglandin E
2
(PGE
2
) are secreted by immune
cells in response, and are known to affect bone,
epithelial and connective tissues. Several of the
cytokines that have been associated with peri-
odontal diseases and local bone and tissue
destruction are interleukin-1 (IL-1), tumor
necrosis factor
α (TNFα), and interferon γ
(IFNγ), among others
10
. These cytokines mediate
the processes of bone resorption and connective
tissue destruction.
78
Enamel
Gingiva
Manual probe
(pocket depth)
Alveolar crest
Ligament
Nerve and
blood supply
Bone
Cementum
Cemento–enamel
junction (CEJ)
Figure 1 Tooth structures with major landmarks defined. Courtesy of the Florida Probe Corp.
POSTMENOPAUSAL OSTEOPOROSIS
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79
100
90
80
70
60
50
40
30
20
10
0
Albania, 69
Austria, 15
Bosnia, 78
Bulgaria, 78
India, 19
Indonesia, 24
Sri Lanka, 37
Thailand, 16
Cambodia, 13
China, 11
Malaysia, 57
Lebanon, 20
Egypt, 7
Gambia, 6
Madagascar, 25
USA, 26
Canada, 58
Saudi Arabia, 40
Singapore, 21
Slovakia, 44
Slovenia, 16
United Kingdom, 46
Denmark, 27
Finland, 41
Hungary, 27
Iceland, 15
Italy, 19
Lithuania, 14
Poland, 25
Romania, 26
NA Africa Asia Europe
Percentage
Figure 3 Edentulousness by selected countries. NA, North America. Source: reference 11
POSTMENOPAUSAL OSTEOPOROSIS AND DENTAL HEALTH
Figure 2 Stages of periodontal disease. Courtesy of the Florida Probe Corp.
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POSTMENOPAUSAL OSTEOPOROSIS
EPIDEMIOLOGY OF PERIODONTAL
DISEASE AND TOOTH LOSS
Periodontal disease and tooth loss are quite
prevalent, but vary by region. Figure 3 presents
the prevalence of edentulousness for selected
regions of the world for subjects aged 65 years
and older. The rates range from less than 10% to
over 60%. Although, in adults, tooth loss is pri-
marily due to periodontal disease, extraction
practices in various regions and trauma also have
an impact on prevalence. In the United States,
by the sixth decade of life, an average person has
lost 12.1 teeth, including the third molars. Men
and women are nearly equally likely to be eden-
tulous. The rate of edentulousness increases with
age, so that about a third (33.1%) of those aged
65 and older are edentulous, although this rate
has declined over the past two decades in the
USA
11,12
.
The prevalence of clinical attachment loss
increases with age, and varies to some degree by
gender. In the United States, the prevalence of
severe periodontal attachment loss increases dra-
matically with age, with nearly one-third of sub-
jects having one or more teeth with 6 mm or
more of attachment loss (Figure 4). Men are
more likely to have at least one site with 6 mm or
more loss. In addition, people with lower socio-
economic status are proportionately more likely
to have severe attachment loss.
Age is one important factor that has been
found to be associated with periodontal disease.
In addition to increasing age, factors that have
been associated with prevalence and severity of
periodontitis include tobacco use
13
, suboptimal
dental care, low education level, low income,
race, gender, genetics and certain medical condi-
tions such as diabetes
3,13
. The risk factors and
risk indicators for periodontal disease have been
reviewed by Albandar
5
. Understanding the inde-
pendent role of each of these factors is compli-
cated by the fact that tobacco use, oral hygiene,
professional prophylaxis and routine dental care
are highly correlated with socioeconomic status,
as are race and ethnicity.
CHARACTERIZATION OF
PERIODONTAL DISEASE
Periodontal disease is assessed by oral examina-
tion, and typically characterized by determining
the degree of loss of clinical attachment of the
soft tissue adjacent to the teeth (CAL) and the
depth of the pocket between the tooth and gum
(PD), or by measuring the loss of alveolar crestal
bone height surrounding the teeth (ACH). A
thorough discussion of the classification of peri-
odontal disease can be found elsewhere
14
.
Pocket depth measurement
The sulcus or pocket depth is one measure of
periodontal disease. It is usually determined by a
probe inserted between the tooth and the gum.
It is the distance in millimeters (mm) from the
gingival margin (GM) to the base of the sul-
cus/pocket (see Figure 1). In research settings it
is typically measured on six surfaces per tooth
(distobuccal, mid-buccal, mesiobuccal, distolin-
gual, mid-lingual and mesiolingual) of all the
teeth present, except the third molars. Both
manual probes and electronic probes can be used
to assess PD. In general, pocket depth is consid-
ered a measure of recent infection, and is influ-
enced by both depth of the pocket per se and
hyperplasia or recession of the gum.
25–34 35–44 45–54 55–64 65–74 75+
0
10
20
30
40
A
g
e (years)
Percentage 6 mm CAL or more
Female
Male
Figure 4 Percentage of US population with at least
one tooth 6 mm or more clinical attachment loss
(CAL) by age and gender. Adapted from reference 12
and National Center for Health Statistics data
80
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POSTMENOPAUSAL OSTEOPOROSIS AND DENTAL HEALTH
thresholds are described with distances over a
predefined level being considered diseased. A
value of 2 mm or less in distance from the CEJ to
the crest of the tooth is considered healthy.
For longitudinal assessment of change, the
technique usually includes a side-by-side com-
parison. Standardization of technique is critical
for proper quantification of change. In longi-
tudinal studies, the baseline radiograph and the
follow-up radiograph are digitized and displayed
side-by-side on a computer screen. The images
are first aligned. Then the CEJs and alveolar
crests are indicated on each image and a
computer algorithm measures the distances and
the difference. This routine requires the reader to
determine whether the two images are aligned
and comparable. Although there is considerable
user interface, the error of the method has been
demonstrated to be low with experienced exam-
iners and standardized collection tech-
niques
16,18–21
. Figure 5 includes two images from
one individual taken 4 years apart. The loss in
ACH is apparent.
Residual ridge resorption
The bone of the jaw where teeth are missing is
called the residual ridge. Several studies have
associated residual ridge resorption (RRR) with
osteoporosis. Researchers have correlated the
severity of osteoporosis with the degree of RRR.
After a tooth is lost, there is resorption or reces-
sion of the oral bone in that region: this phe-
nomenon is RRR. Most often, the extent of RRR
is described in edentulous subjects, but RRR can
be described in dentate subjects who have lost
one or more teeth in the region of tooth loss.
RRR can be described in cross-sectional studies,
but more meaningful information can be
obtained in prospective studies where the rate of
RRR after tooth loss or extraction is described.
Clinical assessment for bleeding,
plaque and calculus
Assessing plaque and calculus is typically done
by examination, with a qualitative assessment
given by the examiner. Plaque is usually assessed
on three surfaces per tooth (buccal, mesiobuccal
81
Clinical attachment level
Clinical attachment level assesses the loss of
attachment of the soft tissue from the surround-
ing teeth, and is defined as the distance in mil-
limeters from a fixed point on the tooth, the
cemento–enamel junction (CEJ), to the base of
the pocket. The clinical attachment level is
thought to be representative of the historical loss
of attachment; however, this loss can be
influenced by factors other than periodontal
destruction, such as aggressive brushing. Peri-
odontal severity increases as the amount of
attachment loss and number of tooth sites
affected increase. More severe disease can be
defined as having 4 mm or more loss of attach-
ment in at least one site. Attachment loss of
6 mm or more is considered very severe disease,
and likely associated with later tooth loss.
Alveolar crestal height
Alveolar crestal height is typically assessed using
oral radiographs. The ACH is a measure of the
distance from the CEJ to the bone crest adjacent
to the tooth, both mesially and distally.
Although studies vary, typically a set of oral radi-
ographs is taken including all teeth present in
the mouth, with the exception of the third
molars
15
. Standardization of the radiographs is
critical, especially if the intent is to use the radi-
ographs in studies of longitudinal change. Tech-
niques employed in research to standardize these
radiographs include the use of positioning
devices such as ear-rods, as first described by Jeff-
coat and colleagues
16
, or a lateral cephalostat
head-holder. In addition, positioning aids such as
lasers are used in standardization. Other impor-
tant considerations include beam length and
angular position to the X-ray film, as well as pro-
cessing technique. The technique for collection of
standardized radiographs has been described by
Hausmann and co-workers
15,17
.
To measure interproximal alveolar crestal
height (ACH), the radiographs are digitized.
Measurements of cross-sectional radiographs
includes computerized assessment of the ACH
distance in millimeters. Typically, the values
obtained are averaged across the entire mouth to
obtain a mean ACH level, or in some instances
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and lingual) and scored as absent or present
22
. A
calculus index is typically scored as absent,
supragingival only or subgingival. Gingival
bleeding is typically assessed in all teeth present,
except for the third molars, by scoring bleeding
(present or absent) upon gentle manipulation.
Tooth loss
Tooth loss is best assessed by an experienced
examiner. Self-reported tooth loss is thought to
be less reliable, and the location of lost teeth is
usually unavailable. The reason for loss (caries,
periodontal disease, trauma, other) is more diffi-
cult to obtain and often relies on recall of the
subject, especially in large-scale studies. Also, the
reason for tooth loss varies greatly across coun-
tries and regions, and may be the result of local
practices and dentist preference, and may not
reliably represent oral bone loss.
Radiographic assessment of oral bone
density
The assessment of oral bone density is one of the
most challenging of all in dental research. Mea-
surement of oral bone density has been per-
formed using a variety of techniques that include
measurement of absolute density (dual energy X-
ray absorptiometry (DXA); dual photon absorp-
tiometry (DPA); quantitative computerized
tomography (QCT); radiographic absorptiome-
try (RA)) of oral bones, and studies that approx-
imate change in oral density over time, such as
computer-assisted densitometric image analysis
(CADIA). All techniques used to assess oral bone
density are limited to some extent by either cost
or precision. QCT provides perhaps the best
assessment of oral density, since it allows assess-
ment of the density in various regions of the oral
bones without obstruction by teeth. However,
this technique is relatively expensive and
includes relatively high exposure to radiation.
Both DPA and DXA have been used to assess
oral bone density. However, positioning and
reproducibility of oral density are difficult, and
may require adaptations to the instrumenta-
tion
23
. RA has been used in several studies,
employing bitewing radiographs taken with a
calibrated step-wedge of known density in the
field of X-ray. Reproducibility of this method is
fairly good when positioning aids are used.
The region of the oral bone measured varies
according to the technique used to assess oral
density. Density assessments in human cadavers
82
At baseline 4 years later
Figure 5 Alveolar crestal height change from baseline to 4 years later
POSTMENOPAUSAL OSTEOPOROSIS
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POSTMENOPAUSAL OSTEOPOROSIS AND DENTAL HEALTH
have shown variation across regions of the
mandible, by edentulation and by age and gen-
der
24,25
. QCT can measure virtually any region.
RA is restricted to regions that can be accessed
by bitewing radiographs. DXA and DPA can
measure the mandible; however, obstruction by
teeth in dentate subjects makes measurement of
the basal bone easier to access and reproduce
than regions surrounding the teeth. Most meas-
urements are made in the mandible due to easier
access. Within the mandible, subregions that
may be measured include molar, premolar or
incisor regions. Each region has the potential to
be of different cortical thickness, which may
affect density, especially using techniques that
are two-dimensional and sensitive to thickness
differences. Most (DXA, RA) but not all (QCT)
measures of oral density are two-dimensional.
The ability to measure oral bone density is
restricted at least in part by whether or not teeth
are present, with edentulous subjects being eas-
ier to assess without potential for tooth obstruc-
tion. However, edentulous subjects may have
marked resorption of the residual ridge, which in
turn affects the area of comparison and ulti-
mately the density. Attempts to use radio-
morphometric indices in panoramic radiographs
to predict skeletal density have been largely
disappointing
26
.
For mandibular density using a step-wedge
technique, an aluminum ramp of known distance
is included in the periapical radiographs. The
ramp generates a density gradient within the
radiograph that is used after digitization to com-
pare regions of bone surrounding the teeth. Here
too, as in ACH determination, positioning is crit-
ical for both reliable assessment of the wedge
(known density) and comparison with bone
regions to determine bone density (g/cm
2
). The
ramp needs to be properly aligned with respect
to the X-ray beam. Various positioning aids assist
in this, including use of ear-rods. These position-
ing aids are needed to ensure that the beam and
ramp are perpendicularly aligned.
In addition to cross-sectional analysis of den-
sity, longitudinal assessment of change can be
obtained by digitization of two radiographs after
alignment, contrast correction and subtraction.
The purpose of the digital subtraction is to iden-
tify the degree of change. An aluminum ramp
included in the radiograph is used as an internal
reference to measure mandibular bone density
20
in mg/mm
2
. Newer techniques to optimize
methods of subtraction and correction are cur-
rently under way.
STUDIES OF THE RELATIONSHIP
OF OSTEOPOROSIS AND ORAL
HEALTH
There is increasing evidence that osteoporosis,
and the underlying loss of bone mass character-
istic of this disease, is associated with oral bone
loss, periodontal disease and tooth loss. Peri-
odontitis has historically been defined as an
infection-mediated destruction of the alveolar
bone and soft tissue attachment to the tooth,
responsible for most tooth loss seen in adult pop-
ulations. Recent studies have shown low bone
mass to be independently associated with meas-
ures of periodontal disease and tooth loss. Grow-
ing evidence supports the role of osteoporosis in
the onset and progression of periodontal disease
in humans, including several prospective studies.
Studies of osteoporosis and loss of soft
tissue attachment
Studies of the relationship between measures of
soft tissue attachment (CAL, PD) and osteoporo-
sis have been mixed (Table 1). Phillips and Ash-
ley
28
found that bone density assessed by the
metacarpal index (MI) was associated with mesial
pocket depth (Russell’s periodontal index), and
was significantly associated when limiting the
assessment to posterior teeth, in 113 females
aged 30–40 years. Ward and Manson
29
were able
to find an association between periodontal dis-
ease index and loss of alveolar bone, but no rela-
tionship between metacarpal index and peri-
odontal index. Elders and others
34
performed
oral examinations and assessed spinal bone min-
eral density (BMD) and metacarpal cortical
thickness (MCT) in 286 women aged 46–55
years. Sixty (21%) of the cohort were edentulous.
In the dentate subjects, no significant correlation
was observed between the clinical parameters of
83
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