Chende Alexandru gr1 An V MD
Senzory function
Many reports suggest that food enjoyment,recognition,and senzory function decline as a function of age
and that this can produce signifiant nutritional deficits. It has been suggested that there is a true anorexia(loss
of appetite) associated with aging, although this is confounded by the many comorbidites that cause anorexia,
and which are so common in elderly people, as well as other social and psychological factors that may reduce
oral food and fluid intake.Perturbation is taste, smell,other oral sensory modalities can occur with age,and with
dental/periodontal problems,increasingly reduce the rewards of eating, thus contribuiting to a diminished
interest in fod among many elderly persons.
The taste receptors of the human gustatory system are distribuited throughout the oropharynx and are
innervated by three cranial nerves:VII IX,and X. It appears that the number of lingual taste buds does not
diminish with age.The registration of a taste phenomenon is complex,because multiple factors are
involved:gustation, olfaction, and central nervous system function.The ability to taste is often evaluated at two
levels: 1threshold,the most common measure, a –molecular level- event, which reflects the lowest
concentration of a tastant than an individual can regonize as being differrent from water and
(2)suprathreshold,a measure that is reflective of the ability to taste the intensity of a substances at functional
concentrations encountered in daily life. In addition to detection recognition,and intensity, the normal
sensation of taste involvecs a hedonic component:the degree of pleasantness.
Many earlier studies citing a higher frequency of taste complaints amoung older persons examined
institutionalized individuals rather rather than healthy elderly people.It now appears that subjective reports of
taste function among generally healthy,community-dwelling persons demonstrat that only modest changes
occur with increased age, in comparison to studies revealing a threefold increase in the frequency of subjective
complaints among older persons who take prescription medications. Objective threshold and suprathreshold
evaluations of gustatory function in healthy older adults have been and in general, the decremental changes
detected with increased age have been modest taste-quality-specific. Foe exemple, the ability of older persons
to detection threshold for sucrose (sweet) are noted. The importance of medication usage and place of
residence in the evaluation of taste dysfunction has been confirmed in clinical studies in which institutionalized
persons and those using more prescription medications had signifiantly elevated taste thresholds.
Older individuals perform less well in the more complicated problems of flavor perception, food
recognition,and food preference.This is probably a result of diminished olfactory perfomance rahter than the
modest changes that accompany taste function with aging.the available data on olfactory perfomance clearly
indicates declines in thresholds,suprathresold intensity judgments,and odor recognition in both men and
women with increasing age.Among older adults, average thresholds are highter, the ability to percive
suprathresold intensities is blunted,odor recognition is impaired and the judgment of pleasantness is reduced
compared with younger subjects.Moreover,longitudinal studies demonstrate that as people get older,
recognition decrements become even more severe.
However, in the real world, people do not typocally taste a single tastant in aqueos form and food that
contain soley olfactory cues are not consumed. Foods are chemosensory mixtures, and the most relevant but
most difficult to obtain measure of gustatory and olfactory function involve the use of complex food analogs. In
one study, younger subjects were significantly better than were elders at recognizing stimuli in blended food.
However, when younger persons redropped to the level of elderly individuals. One conclusion from this finding
is that the daily life chemosensory function of older individuals are handicapped by diminished olfactory
performance. Moreover, it has been suggested that for many persons, the –anorexia of aging- can be reduced
or reversed by adding flavor enhancers to foods.
Many other sensory cues (temperature, texture, pressure) participate in the experience of food enjoyment.
Little research attention has been dedicated to these phenomena. One study demonstrated no age-related
changes in the ability of subjects to distinguish fluids of varying temperatures and viscosities;however, a
specific decline was observed in the perception of localized lingual pressure.
Normal chemosensory function cannot operated independently of good oral health. Numerous oral
conditions can directly of indirectly affect smell system an taste by altering the underlying biology of the taste
or smell system or by introducing exogenous stimuli into the mounth or nose. Many oral conditions, including
fungal/bacterial/viral infections, vesiculobullous diseases, salivary gland hypofunction, poorly fitting
prostheses, and oral manifestations of systemic diseases, can cause chemosensory dysfunction. For example,
inadequate removal of good particles can allow their breackdown or metabolic conversion by oral
microorganisms to noxious, unpleasant substances. Periodontal diseases can result in accumulation of
putrefied acidic materials that may leak into the oral cavity and alter taste sensation. Similary, dental-alveolar
bacterial infection with subsequent fistula formation may contribute continuously low levels of purulent matter
in the mouth.
The complaint of a smell or taste problem may be indicative of a chemosensory disorder or could be the
manifestation of an oral and/or systemic mediacl problem. For example, the sudden loss of either smell or
taste may be a sign of brain tumor. Alternatively, gradual diminishment in food enjoyment may be related to
multiple sources.Older subjects are more likely to have chemosensry complaints, but unfortunately those
complains are very poor predictors of olfactory dysfunction. A patient should be asked if he or she can
specifically identify the four basic tastants and distinguish between differrent odorants; such patients can be
given the University of Pennsylvania Smell Identification Test. A thourgh multidisciplinary approach is required
for a patient presenting with chemosensory complaints because of the wide range of potential oral, systemic,
physiologic, cognitive, and pathologic factors that are involved in oral sensory functioning.
Oral Mucosa
The soft-tissue lining of the mouth may be characterized by three general types:(1)well-keratinized tissue
with a dense layer of connective tissue and firmly attached to underlying bone(marginal gingiva, palatal
mucosa), (2)slightly keratinized and freely movable tissue(labial and buccal mucosa, floor of the mounth), and
(3) specialized mucosa(dorsum of the tongue). The primary function of the oral mucosa is to act as a barrier to
protect the tinderlying structures from desiccation, noxious chemicals, trauma, thermal strees, and
infection.the oral mucosa plays a key role in the defense of the oral cavity.
Aging frequently is associated with changes in the oral mucosa similiar to those in the skin, with the
epithelium becoming thiner, less hydrated, and thus supposedly more susceptible to injury. The reasons for
these changes (if they are normally a sequela of aging) are complex and include alterations in protein synthesis
and resposiveness to growth factors and other regulatory mediators.
Cell renewall (mitotic rates) and the sinthesis of proteins associated with oral mucosal keratinization occur at a
slower rate in aging individuals. Alternatively, the normal tissue architecture and patterns of
histodifferentiation, which probably are dependent on complex interactions with the underlying connective
tissue, do not display any changes with age. Overall, changes in the vascularity of oral mucoasa probably
contribute to an alteration in mucosal integrity because of reductions in cellualr access to nutrients and
oxygenation. Mucosal, alveolar, and gingival arteries demonstrate the effects of arteriosclerosis. Varicosities on
the floor of the mounth and the lateral and ventral surfaces of the tongue(comparable to varicosities on the
lower extremities) are also observable in geriatic patients.
Many studies have documented that the immune system undergoes a decline with age, and it is likely that
this decline extends to mucosal immunity. Therefore, the oral mucosa may be more susceptible to tranmission
of infectious diseases as well as delayed wound healing. Similar findings have been reported for healing gingival
tissue.
Cross-sectional studies have demostrated that age per se has no effect on the clinical apperance of the
mucosa. However, considerable evidence suggests that use of removable prostheses has a potentially adverse
effect on the health of the oral mucosa. The denture-bearing mucosa of aged maxillary and mandibular ridges
shows signifiant morphologic changes. Ill-fitting dentures can produce mechanical trauma to the oral tissues as
well as cause mucosal hyperplasia. Oral candidiasis frequently is found on denture-bearing areas in an
edentulous individual, often occurring with angular cheilitis (deep fissuring and ulceration of the epithelium at
the patient to remove all removable protheses before conducting an adequate oral examination.
Oral mucosal alterations in an older person are often a result of multiple oral and systemic factors.
Numerous medications have been associated with oral mucosal changes. For example, long-term use of
antibiotics frequently result in oral candidal infections, while drugs with xerostomic side effects (see above)
increase the potential for mucosal injury. Bisphosphonate drugs used for cancer metastasis and osteoporosis
(primarily those administered IV, but possibly those delivered orally) have been associated with an unusual but
severe destruction of oral mucosa and bone referred to as osteonecrosis. Drugs commonly used in older
patients for arthritic conditions, hypertension, cardiac arrtythmias, seizures, and dementia are associated with
lichenoid-like reactions. The with-drawal of a causative drug usually results in complete resoltion of the lesion
within 2 to 3 weeks, but if there is no clinical improvement, a definitive diagnosis should be obtained with a
biopsy specimen.