GENERAL NOTIONS ON AGING AND SENESCENCE OF THE ORAL CAVITY
I – Introduction:
The practice of stomatology and maxillofacial surgery in the elderly is currently
increasing sharply due to the increase in life expectancy. It poses
increasingly frequent and restrictive problems in the management of these patients. Indeed, the
repercussions of aging on the different orofacial tissues are expressed by
very diverse pathologies, which are intertwined with each other and more or less directly with the general pathology
. Furthermore, it is sometimes difficult to establish the distinction between a state of “
normal senescence” and a pathological state.
II – Definition:
According to the National College of Geriatrics Teachers:
“Aging is an inevitable, slow and progressive physiological process that results in
the weakening of the body. It is the result of the intertwined effects of intrinsic
(genetic) and extrinsic factors (eating habits, environment, etc.). It is in no way
a pathological state. However, it exacerbates the effects of diseases and their consequences.”
The definition of old age meets different criteria. The age criterion of 65 is most often retained, in particular by the World Health Organization (WHO).
III – Physiology of aging:
The aging process is complex and multifactorial.
The anatomical and physiological changes of old age begin several years before
the appearance of external signs.
There are many theories explaining the mechanisms of aging.
Two major theories have been put forward to explain cellular aging. These are, on the one hand, the alteration of the mechanisms ensuring the life of the cell, and on the other hand, apoptosis or “genetically programmed cell death”.
INTRINSIC FACTORS:
Genetic factors:
Acquired DNA alterations (deletion, mutation) and abnormalities in its repair appear to be involved in aging. They increase significantly with age, particularly in mitochondrial DNA. They are induced by extrinsic factors, such as exposure to radiation.
Indeed, Hayflick’s work showed that cells do not have
unlimited renewal capital. At each cell division cycle, the end of the chromosomes (telomere) loses a fragment.
Protection against free radicals
Free radicals, produced during oxygen metabolism, exert oxidative stress that can damage DNA. Different systems protect the body from free radicals EX: certain antioxidant vitamins (A, C, E).
During aging, there is an increase in the production of free radicals while the protection systems lose their effectiveness.
Non-enzymatic glycation of proteins:
Upon contact with glucose, proteins undergo glycation which modifies the properties of these proteins, making them more resistant to proteolysis and preventing their renewal.
EXTRINSIC FACTORS:
These factors can accentuate the mechanisms of aging. Poor dietary and toxic habits, the environment (ultraviolet rays [UV], ozone, radiation), pathogens are recognized and incriminated as accelerators of aging.
IV – Aging and stomatology:
Effects on the oral mucosa:
Histological alterations: reorganization at the level of elastic fibers and collagen fibers which disappear leaving room for diffuse fibrosis. There is also a degeneration of blood vessels.
Biological alterations: decrease in microbial resistance and immune defenses in general.
Pathological consequences: these conditions promote the installation of age-related lesions: They include dystrophic, infectious pathologies and keratotic white lesions.
Effects on teeth and periodontium:
The combination of carious disease/ periodontal disease is the main cause of tooth loss in the elderly, mainly the loss of molars.
Dental senescence is dominated by three phenomena:
progressive wear of the enamel;
• slow migration of the gingival epithelial attachment towards the dental apex;
• progressive destruction of the alveolar bone.
Effects on bone tissue:
Bone aging results in histological changes: senescent bone is characterized by numerous areas of resorption, by a widening of the central lumen of the Haversian systems, by a decrease in the number and volume of bone trabeculae and a reciprocal increase, within the bone marrow, in the number and volume of fatty deposits and adipocytes by differentiation of osteoblasts.
These changes are linked to hormonal variations in elderly subjects but also to diet and the forces exerted on bone structures.
Pathological consequences of bone aging:
Certain pathologies modifying the expression of factors regulating the bone apposition-resorption balance (steroid hormones, parathyroid hormones) can have repercussions at the bone level. These are essentially osteoporosis, but also Paget’s disease, osteomalacia and hyperparathyroidism.
Effects of aging on muscles:
Muscle senescence causes a decrease in the ability to produce force often
associated with a decrease in muscle mass. The consequence is therefore a
reduced efficiency in reducing food into particles.
This is partially offset by a significant increase in the number of chewing cycles
and a longer chewing time.
Effects on skin tissue:
Skin aging is a complex phenomenon, as for all structures of
the body, involving two main mechanisms. The chronological process, called
intrinsic, affects all the integuments. Extrinsic aging is
essentially the result of the repeated effect of UV rays on photoexposed regions (heliodermia)
which is added to intrinsic aging.
In women, menopause with its hormonal changes accentuates the phenomena of
intrinsic aging. Finally, tobacco aggravates the effects of heliodermia.
Effects on the ATM:
Osteoarthritis and recurrent anterior dislocation appear to be related to the aging of
the ATM. Although these pathologies are not due solely to age, they are closely
correlated with it.
V – Conclusion:
The aging of the population is accompanied by an increased demand for care in
stomatology and maxillofacial surgery.
The practitioner is faced with many difficulties in his approach to elderly patients (
fragile background, polymedication, random participation of the patient, etc.).
In these patients, the risk of under-medicalization or over-medicalization is significant.
All of these considerations sometimes encourage the practitioner to choose his therapeutic approach in terms of quality of life for his patient. To do this, we emphasize the importance
of dialogue with the patient and his family.
Baby teeth need to be taken care of to prevent future problems.
Periodontal disease can cause teeth to loosen.
Removable dentures restore chewing function.
In-office fluoride strengthens tooth enamel.
Yellowed teeth can be treated with professional whitening.
Dental abscesses often require antibiotic treatment.
An electric toothbrush cleans more effectively than a manual toothbrush.