General notions of aging and senescence of the oral cavity
INTRODUCTION
- Dental care for the elderly is currently increasing significantly due to increased life expectancy.
- Indeed, the impact of aging on the different tissues of the oral cavity is expressed by very diverse pathologies which are intertwined with each other and more or less with the general pathology (polypathology).
- EPIDEMIOLOGICAL DATA:
The senior population will continue to increase in number in the coming years.
- 540 million people aged 60 and over in the world, including 330 million in developing countries.
- 1990 the UN dedicates October 1 of each year to the first World Day of Older Persons.
- DEFINITION :
- It is a natural biological process, slow and regular, which often precedes old age, the cause of which is still unknown.
- It is a universal endogenous phenomenon characterized by the progressive reduction of functional capacities (degradation + repair -) whose mechanism involves genetic, extrinsic and pathological factors.
- FACTORS OF AGING:
Aging is different across species, tissues and individuals
- Heredity: several gerontological studies of families, with correlative longevity).
- Maintenance of physical and neurological factors (physical activity throughout life).
- Ecological factors: diet, radiation, medications and quality of care).
- Lifestyle : tobacco, alcohol.
- Psychological and sociological factors : physical decline promotes the isolation of the elderly person.
- Depression : Lack of stimulation aggravates cognitive disorders in the elderly and the non-use of a function counterbalances and accelerates their aging.
- ASPECT OF AGING:
- Morphological aspect:
- The skin: thin, dry, loses its elasticity, becomes covered in wrinkles and pigmented spots.
- Hair and appendages : growth is slowed and the hair turns white, the corners dry out.
- The mucous membrane: atrophies and dries out
VI.2. The biological aspect:
- Mitotic cells: the proliferative power of the cells (keratinocytes) is not fast enough.
- Neurons and striated muscle cells: they are unable to divide after birth and their stock gradually decreases with age.
- Specialized post-mitotic cells of the epithelium (hepatocytes, fibroblasts) only divide after stimulation and their renewal is limited.
- Tissue aging:
- Extracellular matrices ensure integration within tissues, organs and the body.
- They are made of collagens, elastin, proteoglycans and glycoproteins.
- Their aging is characterized by the decrease in the biosynthesis of elastin, elastic fibers lose their elasticity with age and become the target of an enzyme (elastase).
VI.3. The physiological aspect:
- Aging of the nervous system:
- The number of neuronal cells gradually declines over the years (nearly 50% of the initial stock).
- Around the age of 70, brain degeneration results in motor, sensory and sensory disorders.
- Aging of the cardiovascular system:
- Irreversible atherosclerosis is characteristic of senescence.
- The heart loses its ability to contract and adapt to effort (rhythm disorders, heart failure).
- Aging of the respiratory system:
With age there will be a loss of approximately 20% of respiratory capacity, this results from the reduction in lung size and the decrease in elasticity of the pulmonary alveoli.
- Aging of the digestive system:
The main element is atrophy of the mucous membrane of the digestive tract (decreased appetite).
- Skeletal aging:
The skeleton loses its density with age due to bone resorption. In osteoporosis, the spongy bone loses its trabeculation, the cortical bone is reduced.
These changes also affect the maxilla and mandible. Bone tissue gradually weakens from the age of 40.
- Aging of the endocrine system:
- TSH production remains normal, serum FSH and LH concentrations rise after menopause.
- Insulin activity, testosterone and estrogen production gradually decline with age.
- Aging of the immune system:
- Aging of the immune system explains the increased sensitivity to infections by alteration of the cell-mediated response (atrophy of the thymus, decrease in T lymphocyte stimulation factors).
- Aging is accompanied by an increase in circulating autoantibodies and immune complexes.
- Aging of different functions:
- Eyesight declines with age , the main problem:
- Cataract : (poorly controlled diabetes).
- Hearing : hearing acuity decreases
- Taste: the goblet papillae on which the taste buds are located atrophy, with loss of the fungiform papillae .
VII. Aging of orofacial structures:
The manifestations of senescence at the level of the different orofacial structures present certain particularities at the level of:
- Bone structures;
- Masticatory muscles;
- Salivary glands;
- Of the oral mucosa;
- Dental organs.
- Aging of the dental organ: The dental organ evolves over time and participates in the aging process of the organism,
Senescence results in tissue changes in enamel, dentin, pulp, and supporting structures.
- The enamel:
- wear, abrasion ( DVO );
- hyper mineralization (resists cariogenic acids);
- Waterproofness;
- Change color (dark);
- cracks (fracture ).
- Dentin:
- hypermineralized and translucent,
- peritubular dentin progressively reduces the lumen in the dentinal tubules
( sclerodentin = secondary dentin).
- Aging dentin becomes less permeable, which slows down caries progression but promotes fractures.
- The pulp:
The pulp parenchyma undergoes calcific or fatty degeneration .
- The number of odontoblastic cells decreases.
- Collagen fibers increase .
- The vascular and nervous elements which will induce a reduction in pulp sensitivity.
- Pulp volume by secondary dentin edification
- The periodontium:
- The gingiva, periodontal ligament , cementum and alveolar bone undergo progressive, irreversible changes.
- The gum:
Loses its tone and resistance with a reduction in the gum’s ability to repair itself (gingival recession).
- Desmodont: the alveolodental ligament undergoes calcifications and osteosclerosis , the shock-absorbing effect diminishes. The epithelial attachment is increasingly low in relation to the disappearance of the gingival fibers and the resorption of the crest.
- Cementum: its thickness increases significantly at the apical and inter-radicular level to compensate for passive egression (consequence of dental attrition)
- The alveolar bone:
This is the most affected structure ( osteopenia).
Alveolar atrophy results in bone lysis, decreased wall height and thickness of alveolar crests, and decreased interradicular bone . The decreased density of bone trabeculation is due to reduced vascularization.
- Aging of the oral mucosa:
Local and general factors can influence and complicate the modalities of oral mucosal change: tobacco, hygiene and wearing of prostheses, radiation, medication and diabetes.
- Histological alterations:
The mucosa atrophies during aging, the epithelium becomes thinner ( mucosa permeable to attacks in an inflammatory state).
Keratinization disorders become more pronounced and superficial lesions appear. The mucosa of the dorsal surface of the tongue sees its papillae atrophy and becomes smooth.
- Histological alterations:
With age, the collagen and elastic fibers ( in the chorion) change and disappear, leaving room for diffuse fibrosis, the blood vessels change, and there is a failure of the circulatory system.
- Pathological consequences:
- Benign pathology of the mucosa:
- Dystrophic pathology:
Traumatic ulceration: they are of dental or prosthetic origin (poorly adapted).
- Smooth, depapillated tongue:
the mucosa undergoes changes, dries out and loses its papillae. This is made worse by hyposialia; the patient has difficulty eating and swallowing (candidiasis, aphthous ulcers).
- Desquamative gingivitis:
Characterized by
- erythema,
- erosions,
- vesiculobulous eruptions,
- ulcerations and scaling
(lichen planus, cicatricial pemphigoid, hormonal changes).
- Infectious pathologies:
- Candidiasis:
Whitish lesions due to candida albicans. Etiologies (local, general, medicinal)
Candidiasis can be acute, manifesting as a whitish plaque that is removed using a tongue depressor.
The patient complains of dryness and burning.
There are other chronic forms that cannot be removed by scratching: angular cheilitis, median rhomboid glossitis, etc.
The treatment is based on:
- a restoration of the oral cavity:
- Symptomatic treatment.
- Treatment of candidiasis is based on antifungals
- Treatment of hyposialia: hydration, salivary stimulation.
- General treatment in the case of a general defect.
- Shingles:
It is the reactivation of a herpes zoster virus (HZV1) present in the ganglia of the sensory nerves and reactive during a drop in immunity. (Triple syndrome)
- On the mucous membrane level : presence of painful vesicles
- On the neurological level : intense pain in the trigeminal, glossopharyngeal (controls swallowing), facial (facial paralysis) areas.
- On the infectious level : hyperthermia, hyperleukocytosis + asthenia.
- Whitish keratotic lesions:
Tobacco keratosis : more or less localized white lesion of variable thickness can develop into carcinoma.
A biopsy is necessary.
- Lichen planus :
It is an autoimmune disease favored by stress, it affects the entire oral mucosa and can also be located in other places (dotted, dendritic, reticular, erosive, atrophic).
Treatment: corticosteroid therapy and monitoring
- Benign oral tumors:
- Diapneusis
- Lipoma
- Fibroma
- Palatal tumors should be suspected of malignancy and biopsied
- Gingival hyperplasia of prostheses (fibroma) They are due to poorly adapted prostheses Treatment: surgical
- Aging of the jaws:
The mandibular and maxillary basal bone undergo the same remodeling during aging, resorption and signs of osteoporosis with thinning of the cortices and reduction of the trabeculation of the spongy bone (case of edentulation).
The resorption of the maxilla is centripetal, it is centrifugal in the mandible limited by the oblique line and the mylohyoid line (constitutes a sharp submucosal projection, painful on palpation).
- Resorption results in the submucosal positioning of several elements :
- The sinus cavities .
- The mental foramen,
- The incisive foramen ,
- The mylohyoid line.
- Aging ATM
ATM tissue remodeling = physical phenomenon adapted to functional changes in the ATM with age
At the level of the ATM there are degenerative changes but their relationship with age is not certain, such as
- Degenerative lesions of cartilage, articular disc and synovium.
- The development of periarticular osteophytes.
These lesions are not very disabling except in the case of SADAM.
Recurrent anterior mandibular dislocation is the most spectacular and requires emergency treatment . The etiology is multifactorial, the main ones being:
- Complete or subtotal edentulation causing loss of posterior alignment .
- Soft food.
- The flattening of the articular surfaces of the condyle associated with the reduction of its volume results in ligamentous hyperlaxity .
- Muscle aging:
- The efficiency of the masticatory muscles decreases with age, the muscle tissue slowly atrophies, this invalidation results in increasing fragility hampering any effort.
- The muscles lose their tone and there will consequently be a reduction in the execution of functions aggravated by toothlessness.
- Aging of the salivary glands:
- Dry mouth in older people is most often accompanied by
difficulties with chewing, swallowing and speaking.
- This dry mouth is due to the progressive degeneration of the glandular acini which will be replaced by fibrous and adipose tissue with an increase in the diameter of the vessels to the detriment of the functional parenchyma.
CONCLUSION
- The clinical manifestations of aging, although apparent at the facial level, remain a subject of controversy.
- Generally speaking, aging depends on several factors that remain poorly understood.
- However, this aging phenomenon requires good knowledge as well as appropriate care for this category of patients .
General notions of aging and senescence of the oral cavity
Untreated cavities can lead to tooth loss.
Dental veneers restore a harmonious smile in just a few sessions.
Misaligned teeth can cause joint pain.
Dental implants are fixed into the bone for optimal stability.
Chlorhexidine mouthwashes treat gum infections.
Damaged baby teeth can affect speech and chewing.
A toothbrush replaced every three months ensures effective hygiene.