La responsabilidad del estado

N u tritio n al factors have been show n to contribute significantly to the aetiology of m any diseases. N u tritio n al deficiencies could be a consequence of chronic diseases, functional disabilities, social isolation, inad eq u ate or in ap p ro p riate food intake, alcoholism, d en tal problem s an d economic lim itations (D uthie et al. 1983; Lipschitz, 1994). The high prevalence of n u tritio n al problem s in older people justifies th e need to ev alu ate th e n u tritio n a l s ta tu s of older individuals.

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N u tritio n a l sta tu s is very im p o rtan t w hen m aking a general assessm en t of th e h e a lth of th e older people. A n evaluation of th e ability to bite, chew and swallow food safely could provide useful inform ation on th e risk of m a ln u tritio n an d oth er associated problems.

The body m ass index (BMI) is a sta n d a rd m easure of overall n u tritio n . It also has b een u sed as a n u tritio n a l risk assessm ent or assess n u tritio n re late d problem (Osier an d Schroll, 1991; Keller, 1993; P osner et al. 1994; P o tte r et al. 1995). It is a ratio th a t requires only m easurem ent of heig h t an d w eight. BMI w as defined as body w eight in kilogram s (kg) divided by th e sq u are of h eig h t in m etres (m); BMI = kg/m^. BMI is a simple m easu rem en t an d it is applicable to population studies. N orm al ranges of BMI w as defined by ra n k e d body m ass index according to percentile. The range of norm al lies betw een th e 15th and 85th percentile (Cornoni H untley e t al, 1991). M ost of th e studies of th e older people in W estern countries found a body m ass index betw een 21 an d 30 as ‘norm al’ u n d er th is definition (K oughan an d A tkinson,

1993).

N u tritio nal status, chew ing problem s an d prosthodontic treatm ent need

A good oral h e a lth sta tu s is im p o rtan t for chewing ability, ta ste perception, swallowing, phonetics an d comfort (R anta et al. 1988; E kelund, 1989; N orlen et al. 1991). The num ber of n a tu ra l teeth, th e presence of rem ovable p a rtia l d en tu res or full d en tu res m ay be linked to m asticatory efficiency an d ability.

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Poor oral h e a lth can be a p o ten tial reversible factor w hich contributes to th e developm ent of involuntary w eight loss in older people (Sullivan et al. 1993). In ta k e of food in insufficient quan tities is often th e re su lt of d en tal sta tu s such as ill-fitting den tu res or broken or m issing teeth, swallowing problem s an d dysphagia (Gilmore et al. 1995). Chewing problem s w ere often found in older p a tie n ts w ith w eight loss (Fischer and Johnson, 1990). P osner e t al. (1994) considered d en tal h e a lth as one of th e risk factors for p o ten tial n u trie n t deficiencies in th e older people. In a study of th e hospitalised older p atien ts, Mowe e t al. (1994) showed th a t about h a lf of th e u n d ern o u rish ed p a tie n ts h a d more chewing problem s com pared w ith a hom e-living group. In a study of factors related to u n in ten tio n al w eight loss in older adults, chewing problem s, broken or m issing te e th and ill-fitting d en tu res w ere rep o rted in 53%, 28% an d 14% respectively in medical records as factors co ntributing to u n in te n tio n a l w eight loss. Reduced functional ability w as recorded in 63% of th e m edical records (Gilmore et al. 1995).

H olhster an d W eintraub (1993) studied th e association betw een d ietary choices or n u tritio n a l in tak e and oral conditions such as m issing te e th an d poorly-fitting den tu res. They reported th a t food choices an d th e ability to chew are severely lim ited for those who are edentulous or have poorly-fitting d en tu res. This finding is sim ilar to th e study by Mojon e t al. (1995) who found th a t poor oral h e a lth sta tu s is one factor associated w ith n u tritio n a l deficiency in very old people. Poor oral h e a lth sta tu s in th ese edentulous subjects w as defined as having generalised stom atitis, absence of both dentures, broken or inadequate d en tu res and com plaint about lost den tu res.

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An ability to chew in relatio n to different type of dentition could have an effect on food habits. E dentulous subjects w ith poor condition of th e ir d en tu res are m ore likely to choose a soft diet w hich are easy to chew (Smith, 1979). H a rd food is easier to chew w ith n a tu ra l te e th th a n w ith rem ovable prostheses (Chauncey et al. 1984; W ayler et al. 1984). Individuals w ith a rem ovable d en tu re in only one jaw considered th e ir chewing ability to be reduced to th e sam e ex ten t as full den tu re w earers (Chauncey et al. 1984; W ayler et al. 1984; P e terk in e t al. 1987). Removable d en tu res in good condition have been reported to improve chewing ability (Neill an d Phillips, 1970; Neill an d Phillips, 1972; L appalainen et al. 1985). E dentulous older subjects who h a d been fitted w ith new d entures showed th a t th e ir chewing ability increased m arkedly (Baxter, 1981). R an ta et al. (1988) found th a t ad eq u ate reh ab ilitatio n of edentulousness an d w earing of rem ovable denture(s) am ong den tate individuals showed a significant effect on th e ir diets. E d e n ta te s could e a t root vegetables, vegetables and fru its w hich have a hig h n u tritiv e value. In d en tate populations, those w ith rem ovable denture(s) an d those w ith h igher num bers of rem aining te e th increased th e probability of having e a te n root vegetables, vegetables, fruits an d m eat.

V arious studies showed th a t low BMI and n u tritio n deficiency could increase infection ra te s an d complications (Sandm an e t al. 1987), increase h ospitalisation (Keller, 1993) an d even increase m o rtality (Ism ail e t al. 1987; Sullivan et al. 1990; Sullivan, 1995).

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O ral conditions an d den tu re quality affect th e m asticatory ability of full d en tu re w earers (Slagter et al. 1992). The im provem ent of m asticatory perform ance w as reported after m an d ib u lar ridge reconstruction an d the provision of satisfactory new full d en tu res (R enaud et al. 1984).

Shortened Dental Arch (SDA) and the need for tooth replacement

The shortened dental arch (SDA) - the presence of the incisors and canines in both arches and 4 posterior occluding prem olar pairs - has attra cted considerable atten tio n w hen attem pting to reassess dental needs. Helkimo et al. (1978) stated th a t the num ber of te e th is less im portant in term s of chewing efficiency th a n the num ber of contacts betw een them . M any researchers concluded th a t people w ith 20 w ell-distributed tee th seem ed to have a satisfactory chewing abihty (Agerberg an d Carlsson, 1981; Carlsson,

1984; W itter et al. 1990).

K àyser (1981) assessed oral functions in adults w ith SDA. He found th a t w ith decreasing num bers of contacting p airs of posterior te eth th ere w as a tu rn in g point w ith loss of m asticatory function w hen the num ber of occluding un its was less th a n 4 in sym m etrically reduced arches. An im portant "turning range" existed for various oral functions betw een 2 and 4 occluding u n its beyond which dysfunctional changes occurred. For persons over 45 years old w ith m oderate occlusal activity, th ere was sufficient adaptive capacity to m ain tain adequate oral function w ith shortened dental arches of 20 teeth (6 aesthetic un its an d 4 prem olar occluding pairs). M any researchers proposed th a t the decision to replace

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m issing te e th should be done only if they are causing aesthetic an d chewing problems, not to replace all m issing te eth as traditionally been used (Kayser e t al. 1987; K alk et al. 1993). W itter and associates (1994a; 1994b) studied th e long term occlusal stabihty and oral comfort in SDA. they found th a t SDA provided durable occlusal stability. Moreover, they reported th a t the com bination of existing periodontal involvement and increased occlusal loading from removable p artia l denture such as in reduced dentition, could be a potential risk factor for fu rth er loss of teeth.

There w ere more evidences th a t removable p a rtia l denture could not give additional benefit on oral function or chewing perform ance to subjects w ith SDA. W itter et al. (1989) reviewed the effects of removable p a rtia l dentures on the oral function in those w ith SDA. He found th a t th ere were no great differences betw een subjects w ith SDA and subjects w ith SDA and removable p a rtia l dentures (RPD). O osterhaven et al. (1988) reported th a t the num ber of occlusal contacts in the prem olar area was more im portant th a n the num ber of m issing (pre-) m olars for chewing perform ance. The conclusion of W itter et al. (1990) in th e ir review of the effects of shortened dental arches w as th a t "m asticatory abihty is generally sufficient as long as 20 or more 'w ell-distributed' teeth rem ain, such as in cases of SDA.".

Pairs o f occluding posterior teeth (POPs)

The num ber of occluding pairs of tee th has been widely used to determ ine m asticatory efficiency and chewing abihty. Leake (1990) found th a t the

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num ber of opposing pairs of posterior teeth is the most im portant factors in determ ining chewing abihty.

Rosenoer an d Sheiham (1995) m easured w hether older people having m issing posterior teeth had few im pacts and considered th e ir te eth and m outh acceptable. They assessed the relationship betw een satisfaction w ith teeth and m outh and the num ber, position and condition of the n a tu ra l teeth. PO Ps defined as pairs of occluding posterior te e th has been used to assess satisfaction w ith teeth. They found th a t people are satisfied w ith th e ir teeth and m outh even if they have all m olar pairs missing. Thus, satisfaction w ith th e m outh was not related to the num ber of te eth which indicates th a t the num ber of te eth present w ithin the oral cavity is not the major determ in an t of oral well-being. Satisfaction w ith te eth and m outh found to increase w ith an increased num ber of functional m olar pairs. Those w ith more th a n 4 POPs h ad fewer dental im pacts th a n those w ith less th a n 4.

E has and Sheiham (1997) assessed satisfaction in relation to the num ber, position and condition of teeth in B razihan tra n sp o rt workers. They reported th a t th ere was little association betw een m olar pairs and satisfaction. Three prem olar pairs and intact anterior sextants an d no m olars were sufficient to satisfy m ost persons in regard to th eir oral statu s even w hen th e m olar teeth were not replaced w ith p a rtia l dentures.

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In sum m ary, the replacem ent of a tooth will be necessary w hen th e loss of th e tooth affects m asticatory function and cosmetic appearance. In the anterio r area w here th e loss of the tooth often creates cosmetic problem, replacem ent of te e th will solve th e problem and could improve the p a tie n t’s satisfaction of his/her appearance as well as the quahty of hfe. In the posterior area, dental practitioners should be aw are of the concept of shortened d ental arch before m aking the decision w hether to replace or not replace the teeth.