Impact of Water Fluoridation on Dental Practice and Dental Manpower

ORIGINAL ARTICLES

Impact of water fluoridation on dental practice and dental manpower Bruce L. Douglas, DDS, M PH Donald A. Wallace, PhD, C h ica g o Monroe Lerner, PhD, B a ltim o re Sylvia B. Coppersmith, RN, C h ica g o

D ata w e re o b ta in e d on d e n ta l p ra c tic e s a n d on th e c h a ra c te r is tic s o f p a tie n ts an d n a tu re o f t r e a t ­ m e n t o b ta in e d

in

seven m a tc h e d p a irs o f m id -

w e ste rn c o m m u n itie s . T h e re s u lts o f th e s u rve y in d ic a te d th a t flu o r id a tio n d id n o t a ffe c t d e n tis ts ’ in co m e s, fee s, a n d n a tu re o f tre a tm e n t to a n y s ig ­ n ific a n t degree. H ow ever, it a p p e a re d to h e lp ex­ te n d th e e x is tin g d e n ta l m a n p o w e r to c o ve r a s u b ­ s ta n tia lly la rg e r p a tie n t load.

T h e im pact o f water fluoridation on dental caries is now w ell established. M any studies have shown that ingestion o f fluoridated water during the tooth-form ative years m ay decrease th e incid en ce o f caries from 35% to 80% . B ecause treatm ent o f dental caries is believed to constitute an im p or­ tant proportion o f the practices o f m any dentists, it seem s reasonable to suppose that w idespread introduction o f fluoridation m ay ultim ately h ave a substantial im pact on th e pattern o f dental p rac­ tice and, perhaps, on dental manpower. T h e p recise nature o f the im pact o f fluorid a­ tion on dental p ractice is not known, although it has been the subject o f considerable speculation. O ne lin e o f reasoning holds that w idespread in ­ troduction o f water fluoridation should lead to a substantial decrease in the effective dem and for dental care. I f this were true, with the supply o f dental services rem aining constant, w ould fees for dental services be expected to decline, with a

concom itant decline in incom es am ong dentists? A lso, if effective dem and decreases, w ould hours w orked by dentists and their degree o f “ busyness” be expected to be reduced? A ccording to another lin e o f reasoning, effective dem and m ight not decrease, because the unm et n eed for dental ser­ vices is so great that m easures, in addition to fluoridation, are n eed ed to bring dem and and su p ­ ply into balance. I f this were the situation, then it m ight be possib le for dentists w hose practices w ere affected by fluoridation to serve th e needs o f a larger population than form erly, perhaps w ith ­ out much change in current patterns o f p ractice or even in their econom ic position. On the assum ption that there was no decrease in effective demand, another lin e o f speculation m ight hold that dentists in fluoridated com m u n i­ ties should be ab le to m eet the n eed s o f their current patients m ore com p letely than is now p o s­ sible. Similarly, there m ight logically be a shift in em phasis o f dental practice. L ess tim e m ight be spent on oral surgery and in correcting caries in children’s teeth than at present; m ore tim e m ight be devoted to orthodontic, endodontic, and p o s­ sibly periodontal care, to restorations in adults’ teeth, to prosthodontics, and to preventive d en ­ tistry and patient education. N o n e o f these speculations had been tested u n ­ der the controlled conditions o f an experim ental study, probably because o f the difficulty o f d e­ signing and conducting this type o f study in a real life situation. H ow ever, studies h ave been carried out on related subjects: for exam ple, th e im pact o f fluoridation on dental disease, including d en ­ tal caries, periodontal disease, and m alocclu ­ sion, and the persistence o f this im pact into adult­ hood; the im pact o f fluoridation on dental costs and m an-hours required for dental care (usually under the artificial con d itions o f group practice); JADA, Vol. 84, February 1972 a 355

and th e im pact o f fluoridation on the age at which dental care is first sought. A brief review o f som e o f th e m ore relevant o f these studies follow s.

R eview of th e literatu re T h e literature dem onstrating th e beneficial e f­ fects o f water fluoridation on dental health is v olu m in ou s.1-2 For exam ple, studies have shown decreases in th e incidence o f caries ranging from 35% to 8 0 % . T h e prevalence o f both periodontal d isease in young adults3 and m alocclusion in c h il­ dren4 has been found to be low er in fluoridated areas. Englander5 has dem onstrated that these b en eficial effects o f fluoridation con tin u e into early adulthood. In another study in which p o p u ­ lation s at ages 18 to 59 were com pared, Englander and W allace6 show ed that these effects persist at least to th e age o f 60. T h ese investigators found that th e p revalen ce o f dental caries, evaluated by teeth and surfaces, was roughly 40% to 50% higher am ong 8 9 6 native w hite residents o f fluor­ id e-d eficien t R ockford, 111, than in optim ally fluoridated A urora, 111. H ow ever, the differential narrow ed with increase in age o f subjects. R ussell and E lvove7 also dem onstrated the persistence throughout adulthood o f the beneficial effects o f fluoridation. T h ey found that, for all ages c o m ­ bined, the average n ative resident o f C olorado Springs, w here the water is naturally optim ally fluoridated, had approxim ately 60% few er carious lesion s than the average n ative resident o f B o u l­ der, C olo, w here the water is fluoride-deficient. T h e b en eficial effects o f fluoridation on dental health h ave been reflected in reduced dental co sts to th e patient and in few er dental m an-hours required for care. In confirm ation o f this, A st and co-w orkers8 found that ch ild patients required few er services per child, and the mean cost o f treatm ent per ch ild was low er in N ew burgh, N Y , w here the water is fluoridated, than in Kingston, N Y , w here it is fluoride-deficient. In the latest o f a series o f reports dealing with the effects on c h il­ dren’s teeth o f controlled fluoridation in these tw o com m unities, A st and h is associates9 said, “T h e cost for corrective care for children with life-lon g exposure to fluoridated water is less than h a lf o f what it costs in a non fluoridated area, and increm ental care is just about h alf.” T h ese findings have been confirm ed by a sim ilar study in N e w Z ealand by D en b y and H o llis10 and in studies by B layn ey11 and M itch ell.12 Finally, the relationship between fluoridation and the 356 ■ JADA, Vol. 84, February 1972

n eed and effective dem and for dental services w as outlined by Striffler13 in h is report o f a study carried out in N ew M exico. M uhler,14 in a com parison o f three Indiana com m unities, found that children brought up on fluoridated water seek dental care for the first tim e at a later age than children brought up on fluoride-deficient water. Perhaps as a consequence, th e m ean level o f their oral h y g ien e was found to b e som ewhat lower. T h is latter d ifference was especially n oticeab le at the ages o f 6 to 8 years. T erhune and M u h ler,15 in a survey reported w ell after this study began, studied th e effects o f fluoridation on dental p ractice in tw o u nid en ti­ fied, com parable m idw estem cities with p opu la­ tions o f m ore than 3 0 ,0 0 0 . In o n e o f th ese cities, “ A ,” the water was fluoride-deficient, whereas in city “ B ,” it was classified as naturally fluoridated. T h e survey findings included the follow ing: There w ere approxim ately 20% m ore dentists in B (1 to 2 ,0 6 0 p opulation) than in A (1 to 1,550). Thus, fluoridation cou ld be considered as a factor that increases the patient load a dentist cou ld treat. A s w ould be expected, annual dental expenditure per capita w as about 50% higher in A ($ 2 2 .9 5 ) than in B ($ 1 5 .7 2 ). H ow ever, and som ewhat surprisingly, instead o f having an adverse im ­ pact, this low er annual per capita dental exp en d i­ ture in B was associated with higher m ean gross in com es for general practitioners in that city. G eneral practitioners in B averaged a gross an­ nual in com e o f $ 3 2 ,9 0 0 , which w as about 10% higher than the average $ 2 9 ,9 0 0 reported for A. T h e net annual in com e w as $ 1 1 ,2 8 5 in the fluor­ id e deficient city and $ 1 7 ,7 4 6 in the optim ally fluoridated city. T h ese figures were obtained in on ly tw o com m unities, w hereas this study includes seven pairs o f m atched com m unities. T h e sam e survey, based on data provided by dentists about their practices, found that dentists in A perform ed substantially m ore preventive procedures, and that they also generally p er­ form ed slightly m ore repair, rem oval, and re­ placem ent procedures. T h e survey also found that, in general, residents o f the fluoride-deficient city received m ore o f m ost types o f dental treatment, especially extractions and pedodontic procedures. Overall, how ever, th e patterns o f treatm ent ren­ dered by the general practitioners and reflected in their practices w ere q uite sim ilar. T h e authors w ere careful to note the lim itations o f their study, thereby restricting the valu e o f a generalized co m ­ parison o f their findings with those in other co m ­ m unities. A lso, their findings w ere reported as

contradictory to som e findings by M u h ler.14 D o u g ­ las and C oppersm ith16 h ave review ed the litera­ ture on the im pact o f fluoridation on dental p rac­ tice. T h e present study w as designed to test these hypotheses: ■ T h e patterns o f dental practice, including the characteristics o f dentists (age, years in p ra c­ tice, specialty, type o f practice, and so on), effort by and financial return to the dentist, character­ istics o f patients, and nature o f treatm ent are d if­ ferent in fluoridated and fluoride-deficient c o m ­ m unities. ■ D en tists in fluoridated com m unities serve a larger patient load than do dentists in fluorided eficient com m unities. T h is occurs because n eed for care is substantially reduced by fluoridation. N evertheless, a large unm et need for dental ser­ v ices continues to exist.

M eth o d of study D ata w ere ob tain ed during January-February 1967, on dental p ractice during the w eek o f O ct 17 to 22, 1966, in seven m atched pairs o f sm all m idw estem com m unities. T h e w eek w as selected as o n e that w as least subject to system atic d evia­ tion from the norm al w eekly pattern. Sum mer vacations w ere com pleted, whereas winter v a c a ­ tions had not yet begun; the school year w as w ell under way; the w eek contained no legal or r e li­ g iou s holidays; and no state, regional, or national dental m eetings were taking place. In on e c o m ­ m unity o f each pair, water supplies were naturally fluoridated at optim um levels; in th e other, the water w as fluoride-deficient. O ptim um natural fluoride levels ranged from 0 .7 to 1.2 parts per m illion; fluoride-deficiency was defined as less than 0 .4 parts per m illion. E xisting p ub lish ed reports o f chem ical analyses w ere consulted. D ata on characteristics o f dentists, their practices, and som e aspects o f their effort and financial attain­ m ent w ere ob tain ed by personal interview with the practicing dentists. D ata on characteristics o f p atients and nature o f treatm ent were obtained from patient records. T h e fluoridated com m unity o f each pair w as selected first. T h e m atching was based on 1960 census data on population size, age and sex c o m ­ position, fam ily incom e level, educational at­ tainm ent, and percent native-born and their years o f residency in the com m unity. (A ssistance in m aking the selection w as furnished by the N a ­

tional O pinion R esearch C enter o f the U niversity o f C hicago.) G eographic or interstate variations or both w ere m inim ized by selection o f m atched pairs from the sam e state. A ll study com m unities are in the states o f Illinois, Indiana, and O hio. A lso, hom ogeneity in the study was m aintained because no large cities were included. T h e select­ ed pairs exhibited m inim um ethnic diversity. T h e m atched pairs (fluoridated com m unities listed first) were: A urora and F reeport-K ankakee, 111; K ew anee and C entralia, 111; M arion and San­ dusky, Ohio; Joliet, 111 and M ansfield, O hio; E lw ood and C onnersville, Ind; H untington and Shelbyville, Ind; and Frankfort and C raw fordsv ille, Ind. R ockford, 111, w as originally selected for pairing with Aurora; how ever, a large p ro ­ portion o f its dentists refused to participate in the study. B ecause no single com m unity w as avail­ able as a suitable substitute, F reeport and K anka­ k ee were paired with Aurora. T h e total p o p u la ­ tion o f the 15 com m unities w as estim ated at 4 5 5 ,7 0 0 as o f the end o f 1967, with 2 4 7 ,5 0 0 in the fluoridated and 2 0 8 ,2 0 0 in th e fluoride-deficient com m unities. A lthough the 1966 edition o f the Am erican Dental Directory lists 3 4 6 dentists practicing in the survey com m unities, on ly 318 co u ld b e lo ­ cated (1 6 2 in the fluoridated com m unities, 156 in th e fluoride-deficient com m unities). T h e rest had either m oved, retired, or died. O f this num ­ ber, 278 (8 7 % ) agreed to participate in the study; 144 were in the fluoridated com m unities, and 134 w ere in the fluoride-deficient com m unities. Patient-record data w ere ob tain ed from 2 5 6 o f the 278 dentists interview ed. N o attem pt was m ade to obtain th ese data from the 17 orth­ odontists (eight in the fluoridated and nine in the fluoride-deficient com m un ities) interviewed; fiv e general practitioners w ould not allow their patient-record data to be review ed. (A fuller ac­ count o f the research design, strategies for o b ­ taining dentists’ cooperation, techniques o f ab ­ stracting patient records, and th e lim itations o f the study is available elsew h ere.17) Supplem entary data subsequently w ere ob tain ed from 4 2 den­ tists in active p ractice in P ueblo, C olo, (where water is naturally fluoridated) and 45 dentists in Beaum ont, T ex, (which has fluoride-deficient water). T he com parability o f these tw o cities for use in this study is lim ited because Beaum ont is the center o f a larger m etropolitan area than Pueblo. D ental practice in Beaum ont is much m ore a “ downtow n” or “central business district” type o f practice. Douglas—others: FLUORIDATION AND DENTAL MANPOWER ■ 357

R esults o f survey of m idw estern c o m m u n itie s

■ D entist-population ratios: O n ly dentists p rac­ ticing in the m unicipal boundaries o f the 15 c o m ­ m unities were included in this study; as a co n se ­ quence, residents w ho received dental care o u t­ side th e com m unities w ere excluded. T h is p o s­ sib le source o f bias should h ave affected both fluoridated and fluoride-deficient com m unities equally. T ab le 1 show s that each practicing dentist in th e fluoridated com m unities served an average o f 1,528 residents, about 14.5% m ore than th e c o m ­ parable average o f 1,335 served in th e fluorided eficien t com m unities. T h e dentist-population ratio w as 6 5 :1 0 0 ,0 0 0 in the fluoridated c o m ­ m un ities com pared with 7 6 :1 0 0 ,0 0 0 in the fluor­ id e-d eficien t com m unities. T h e sam e pattern (den­ tists in fluoridated com m unities serving larger p opu lations) w as evident for six o f the seven pairs o f com m unities, including the three largest (A u ­ rora and Freeport-K ankakee, Joliet and M an s­ field, and M arion and Sandusky). In th e seventh pair (E lw ood and C onnersville), the pattern was uncertain. P opulation data for E lw ood w ere o b ­ tained from a different source (T able 1). F luoridation is believed to have its prim ary dental im pact on persons who ingest fluorides during their ch ild h ood years; how ever, th e high rates o f m obility in the A m erican population m ake it lik ely that m ost present residents o f th ese m idwestern com m unities w ould not have been c o n ­ tinu ous residents since birth. A substantial d if­ feren ce in this characteristic among the tw o sets o f com m unities cou ld produce a major distortion in survey results. T here appears to be no a priori reason w hy th e tw o sets o f com m unities should differ. T h is w as checked in a supplem entary sur­ v ey and no such difference w as discovered. Late

in 1967, the supplem entary survey w as conducted in the study com m unities. Each participating d en ­ tist w as asked to obtain background data from 50 patients, “chosen at random ,” during the next m onth. T h e response rate w as similar: 54% in the fluoridated and 58% in the fluoride-deficient com m unities. In the fluoridated com m unities, 55% o f the patients surveyed and, in th e fluoridedeficient com m unities, 56% said they had resided there continuously. T h ese respondents were not the sam e patients on w hom treatm ent data had been collected in the original survey, although there m ay h ave been a slight overlap. O f course, this m eans that alm ost h a lf had not resided there continuously— the im plication is that the present survey only m easured about h a lf the im pact o f fluoridation. Thus, if th e bias o f m igration w ere rem oved, dentists in fluoridated com m unities ac­ tually m ay be able to serve double the 14.5% larger patient load that this survey indicated.

■ Characteristics o f dentists and their practices: A lthough dentists in fluoridated com m unities serve substantially larger populations, their ch ar­ acteristics and practices appear to b e virtually u n ­ affected by fluoridation. For exam ple, as T ab le 2 shows, th e m edian age o f dentists in the fluori­ dated com m unities w as 4 5 .1 years, w hereas it was 4 5 .3 years for dentists in the fluoride-deficient com m unities. T h ese m edians are m ore than a year low er than the com parable figures from the 1963 and 1967 A m erican Dental D irectory (4 6 .4 and 4 6 .6 years o f age, resp ectively.) H ow ever, they exceed by about two years the com parable m e­ dians reported in the 1 9 6 5 18 and 1 9 6 8 19 surveys o f dental practice (4 2 .3 and 4 2 .1 years o f age, respectively). In tw o o f the three largest pairs o f the m atched com m unities, th e m edian age o f d en ­ tists was higher in the fluoridated com m unity. B ased on m edian ages, no system atic pattern o f difference in age com p osition o f dentists was ev i­

T able 1 ■ Dentist-population ratios among fluoridated and fluoride-deficient com m unities, 1967. Fluoridated Com m unity

F luoride-deficient '

Population per dentist

Population*

D e n tis ts t

All com m unities Aurora, ill

247,500 71,800

162 55

1,528 1,305

Kewanee, III Marion, O hio Joliet, III Elwood, Ind Huntington, Ind Frankfort, Ind

16,600 38,900 76,300 11,500* 17,000 15,400

8 20 57 5 8 9

2,075 1,945 1,339 2,300 2,125 1,711

C om m unity All com m unities FreeportKankakee, III Centralia, III Sandusky, O hio M ansfield, O hio Connersville, Ind Shelbyville, Ind Craw fordsville, Ind

'P o pu la tio n estim ated as o f Dec 31,1967, Sales M anagement, June 10,1968, p D60, D159. tD e n tists in active practice. *D ata from Rand-McNally Atlas, January 1969 (unavailable from Sales Management).

3 5 8 ■ JADA, Vol. 84, February 1972

P opulation*

D e n tis ts f

208,200 28,600 30,300 15,100 34,600 51,800 18,500 14,800 14,500

156 25 28 10 22 46 8 8 9

Population per dentist 1,335 1,111 1,510 1,572 1,126 2,313 1,850 1,611

A bout 88% (1 2 6 o f 144) o f th e dentists in the fluoridated com m unities w ere general practition ­ ers, whereas th e com parable percentage w as about 90% (1 2 0 o f 134) in the fluoride-deficient c o m ­ m unities. (T hese proportions are not u n lik e those reported in the 1 9 6 5 18 and 1 9 6 8 19 surveys o f d en ­ tal practice. In th e 1968 survey, for exam ple, 8 5.2% o f the respondents classified them selves as general practitioners and 14.8% as specialists. T h e 14.8% included som e public health dentists, by definition excluded in th e present survey. T he categories o f specialists were: orthodontists, 5 .0 % ; oral surgeons, 3 .6 % ; pedodontists, 1.8% ; periodontists, 1.5% ; prosthodontists, 1 .1% ; and endodontists, 0 .7 % . (T he 1968 survey co u ld be expected to include larger proportions o f sp ecia l­ ists because it included large cities.) In this study, the 18 specialists in th e fluoridated com m unities included eight orthodontists, six oral surgeons, on e periodontist, tw o pedodontists, and on e prosthodontist; in the fluorid e-deficient c o m ­ m unities, there were n in e orthodontists, four oral surgeons, and o n e prosthodontist (no p eri­ odontists or pedodontists). A ll th ese specialists w ere in the three largest pairs o f com m unities; thus, it appears, specialization is related to c o m ­

dent am ong the two sets o f com m unities. In ad­ dition, no relationship em erges from the c o m ­ parison o f age-distribution (Table 3), except that o f a larger proportion o f dentists aged 6 6 and over in the fluoridated com m unities. Y ears in p ractice (Table 4 ) do not differ syste­ m atically am ong the dentists in these pairs o f com m unities. T h e m edian w as slightly higher for the com b ined total o f fluoride-deficient com m un ­ ities, 17.5 years, than for the fluoridated c o m ­ m unities, 16.7 years, and for two o f the three largest pairs o f com m unities. Table 2 ■ Selected their practices in communities, 1966. Characteristics of dentists interviewed No. dentists Median age Median yr in practice

characteristics of dentists and fluoridated and fluoride-deficient Fluoridated com m unities

F luoride-deficient com m unities

144 45 1

134 45.3

16.7

17.5

Generalists Specialists Generalists as % of total

126 18 88%

120 14 90%

Solo practice Partnership, associateship, and other Solo practice as % of total

126 18

121 13

88%

90%

Table 3 ■ Age groups of dentists

in

fluoridated and fluoride-deficient

communities, 1966. Fluoridated com m unities Age group

No

All ages

143*

-31 31-35 36-40 41-45 46-50 51-55 56-60 61-65 66+

10 21 21 24 17 13 9 9 19

Fluoride-deficient com m unities %

No.

%

100.0

134

100 0

6.9 14.7 14.7 16.9 11.8 9.1 6.3 63 13.3

10 14 25 21 18 19 11 6 10

75 10.4 18.6 15.7 13.4 14.2 8.2 4.5 7.5

’ Age was not determined for one dentist

Table 4 ■ Years in

of

Years in practice

Fluoridated com m unities

practice deficient communities, 1966.

Total -1 1-5 6-10 11-15 16-20 21-25 26-30 31-35 36-40 41 +

dentists

in

fluoridated

and

fluoride-

Fluoride-deficient com m unities

No.

%

No

%

144 2 24 12 32 14 12 13 8 12 15

100.0 1.4 16.7 8.3 22.2 97 83 90 56 8.3 10.4

134 3 14 19 27 13 17 16 6 7 12

100.0 2.2 10.5 14.2 20.1 9.7 12.7 11.9 4.5 5.2 9.0

Douglas—others: FLUORIDATION AND DENTAL MANPOWER ■ 359

m unity size rather than to the presence or absence o f fluoridation. T h e m ajority o f dentists interview ed in this survey were in solo practice: 88% in th e fluori­ dated com m unities and 90% in the fluoride-deficien t com m unities. T h e rem ainder w ere in part­ nerships (9% in th e fluoridated and 5% in the fluorid e-deficient com m unities) or associateships (5% and 4 % , respectively), or they w orked as em p loyees o f another dentist (1% in both). Form s o f practice other than solo were reported alm ost entirely in th e three largest pairs o f com m unities. T h is can be com pared with The 1968 Survey o f D ental Practice 19 which shows: nonsalaried p rac­ tic e w ithout partners, with no sharing o f costs, 6 8 .8 % ; nonsalaried practice without partners, but sharing costs o f o ffice expenses, 8 .1 % ; n o n ­ salaried p ractice as a partner in a partnership, 4.6% ; em p loyed by another dentist, 3.5% ; on staff o f a dental school, 1.9% ; other position as a sa l­ aried dentist, 3 .8 % ; and a com bination o f these types, 9 .3 % . In other aspects o f dental practice, the sim ilar­ ities betw een the tw o groups o f dentists w ere

considerable. Sim ilarities in clu d ed at least these items: use o f anesthetics in op erative dentistry, whether for children or adults; routine instruc­ tion o f patients in oral hygiene; use o f a regular recall system; setting special tim e aside for em er­ gencies; and spending som e tim e in organized courses in dentistry. ■ Direct effort by dentists: T h e characteristics o f th e dentists and those aspects o f their practices considered thus far do not appear to differ greatly among fluoridated and fluoride-deficient c o m ­ m unities. H ow ever, the effort, whether direct or indirect, expended by the dentists in the fluoridedeficient com m unities d oes appear to exceed th e effort expended by those in the fluoridated com m unities (T able 5). A lthough the differentials found in this survey are n ot enorm ous, they are consistent in direction. D entists in fluoride-deficient com m unities spent slightly m ore hours per w eek in their p rac­ tices than dentists in fluoridated com m unities, according to the data. T h e m edian number o f hours w orked per w eek by dentists in fluoride-

Table 5 ■ Dentists’ direct and indirect effort and percent of dentists with assistants in fluoridated and fluoride-deficient com m unities, 1966. Direct and in d ire ct effort

Direct effort Median hr per week in office Median days per week in office Estimated* median hr per w orking day Indirect effort Mean av no operatories One Two Three or m ore Dentists with; Full-tim e employees Part-tim e employees Dental assistants Full-tim e One or more One Two or more Part-time One or more One Two or more Receptionists Full-tim e Part-tim e Hygienists Full-tim e Part-time Dental laboratory technicians Full-tim e Part-tim e Bookkeepers Full-tim e Part-time Full-tim e DDS employees O ther employees Full-tim e Part-tim e 'Estim ated by dividing median hours by m edian days

360 ■ JADA, Vol. 84, February 1972

Fluoridated com m unities

F luoride-deficient com m unities

38 85 4.61 8.43

39.15 4.65 8.42

2.02 28.5 47.2 24 3

2 10 13.4 65.7 20.9

%

%

80 6 29.9

87.3 40.3

75 0 61.1 13.9

84.3 71.6 12.7

14.6 12.5 2.1

20.9 17.9 30

26 4 4.9

14.9 6.7

6.3 7.6

7.5 12.6

4.2

4.4 2.2

2.8 4.2 1.4

5.2 8.2

14 1.4

1.5 07

T h ese are clearly item s intended to increase the dentists’ efficiency, that is, their output per m anhour o f work. N o t surprisingly, according to the data shown in T able 5, dentists in fluoride-deficient c o m ­ m unities used a som ew hat higher m ean average num ber o f operatories (2 .1 ) than the com parable mean average for dentists in fluoridated c o m ­ m unities (2 .02). (T his is equivalent to the n u m ­ ber o f “chairs” in The 1968 Survey o f Dental Practice. 19 T h e m ean number o f “chairs” per dentist in that survey was 2 .3 .) A bout tw o thirds o f the dentists in th e fluoride-deficient co m m u n i­ ties had tw o operatories, but som ew hat less than a h a lf did in th e fluoridated com m unities; in c o n ­ trast, about on e in four dentists in the fluoridated com m unities had o n ly o n e operatory, w hereas in the fluoride-deficient com m unities, th e co m p a r­ able proportion w as on ly about on e in eight. Similarly, dentists in the fluoride-deficient com m unities were m uch m ore lik ely to u se v a ri­ ous types o f auxiliary personnel. For exam ple, larger proportions o f dentists in fluoride-deficient com m unities em ployed full-tim e em ployees (87.3% as com pared with 80 .6 % in fluoridated com m unities), or part-tim e em ployees (40.3% com pared with 29.9% respectively). A d ifference among the tw o groups o f dentists w as evident not only in the proportion using dental assistants (full-tim e, 8 4.3% in fluoride-deficient co m m u n i­ ties and 75.0% in fluoridated com m unities, and part-tim e, 20.9% and 14.6% respectively), but also in the proportion using hygienists, dental laboratory technicians, and bookkeepers. O nly in the category o f receptionists was the direction o f this d ifference reversed; a larger proportion o f the dentists in the fluoridated com m unities em ­ p loyed this typ e o f assistant.

deficient com m unities was 39.1 5 , com pared with 3 8 .8 5 in fluoridated com m unities, for a d ifference o f three tenths o f an hour (18 m inutes per w eek). D en tists in fluoride-deficient com m unities w ere found to work 4.6 5 days a w eek com pared with 4 .6 1 days for dentists who practiced in fluoridated com m unities, or 0 .0 4 days d ifference (20 m inutes per week). A lthough the average num ber o f hours w orked per day was not asked in this survey, it can be approxim ated from these data by division o f m edian hours per w eek by m edian days per w eek. T h is reveals an alm ost identical w orking day for both groups o f dentists, 8 .4 3 hours for dentists in fluoridated com m unities and 8 .4 2 hours for dentists in fluoride-deficient com m u n i­ ties. D esp ite th e indication o f only a sm all d ifferen ce in hours w orked per w eek, a larger proportion o f dentists in the fluoride-deficient com m un ities appeared to feel overworked. A s T ab le 6 shows, 37% o f the dentists in the fluoride-deficient c o m ­ m unities reported that they refused som e ap­ pointm ents and 17% (a total o f 5 4 % ) reported feelin g overw orked although they accepted all requests. In the fluoridated com m unities, only 18% reported that they refused any appointm ents, and an additional 19.4% felt overw orked, for a total o f 37.5% who were either overw orked or cou ld not accept all potential patients. T h e great­ er p revalence o f feeling overw orked am ong d en ­ tists in the fluoride-deficient com m unities w as consistent with the longer period, according to their replies, required for a patient to obtain an appointm ent, 14.1 days com pared with 10.4 days in th e fluoridated com m unities.

■ “Indirect” effort by dentists: M easurem ent o f indirect effort o f dentists w as based on the n u m ­ ber o f operatories in their offices and the num ber o f various types o f auxiliary personnel em ployed.

■ Dentists’ output: D entists in fluoride-deficient com m unities exerted slightly m ore direct effort

Table 6 ■ Degree of busyness among dentists in fluoridated and fluoride-deficient com m unities, 1966. Fluoridated com m unities

Degree of busyness’

All dentists Must refuse some appointm ents Accept all appointm ents, but overworked Accept all appointm ents, not overworked Prefer a heavier workload Lim it practice by choice Refused to answer

F luoride-deficient com m unities

No.

%

No.

%

144 26

100 0 18 1

134 50

100.0 37.3

28

19.4

23

17.2

55 8 26 1

38.2 56 18.0 07

38 4 18 1

28.4 3.0 134 0.7

'R espondents were offered the alternatives listed in answer to the question, “ W hich statem ent best describes your practice'7’’

Douglas—others: FLUORIDATION AND DENTAL MANPOWER ■ 361

and substantially m ore indirect effort; this was associated with a corresponding excess in output, according to th e data. T h e m edian annual number o f patient sittings provided by dentists in fluor­ id e-deficient com m unities, 3,125 (T able 7), ex ­ ceed ed th e com parable m edian in fluoridated com m unities, 3,0 0 0 , by about 4 % . T h e differen­ tial in m edian annual num ber o f patients seen w as even larger, 1,084 and 1,016 respectively— an excess o f just under 7% seen by dentists in fluoride-deficient com m unities. Based on these figures, the average num ber o f tim es each p a ­ tien t w as seen during the year was 2.95 in fluori­ dated and 2.8 8 in fluoride-deficient com m unities, a d ifference o f on ly about 2% . T h e differential in output is even greater co m ­ puted on a daily basis (than when the data were collected on an annual basis). T h e m edian num ­ ber o f patient sittings each working day o f den­ tists in fluoride-deficient com m unities w as 15.34, 8% m ore than th e com parable m edian o f 14.22 for dentists in fluoridated com m unities. T h e 8% differential in patient sittings com puted on a daily b asis com pared with th e 4% difference on an an­ nual basis m ay reflect a larger number o f annual working days for dentists in fluoridated com m un ­ ities. B ased on ratios derived from the foregoing figures, dentists in fluoridated com m unities aver­ aged 211 annual working days com pared with 2 0 4 days in th e fluoride-deficient com m unities. For fluoridated towns, 3 ,0 0 0 annual sittings d i­ vid ed by 1 4.22 daily sittings equal 211 days; for fluoride-deficient towns, 3,125 annual sittings divid ed by 15.34 daily sittings equal 2 0 4 days. H ow ever, each dentist in the fluoridated com m un ­ ities spent, on the average, a slightly longer tim e with h is patient during each sitting. A ccording to estim ates furnished by these dentists, th e m edian duration for each sitting w as 34 .6 m inutes in the fluoridated and 33.8 m inutes in the fluoride-deficien t com m unities. T h ese differentials in output, whether on an annual or daily basis, are based on verbal esti­ m ates o f the dentists in response to item s on a

questionnaire. H ow ever, th e direction and, to som e degree, the m agnitude o f th e estim ates were confirm ed by the inform ation extracted from p a ­ tient records. T h ese records show ed that for the w eek surveyed, patient-sittings am ong dentists in fluoride-deficient com m unities, m ean average o f 5 8 .6 1 per dentist, exceeded by 2.5% the c o m ­ parable mean average in fluoridated com m unities, 5 7 .1 7 per dentist. (Patient-data records w ere o b ­ tained for 7 ,2 0 9 sittings during the survey week from 123 dentists in the fluoride-deficient c o m ­ m unities, a m ean average o f 5 8 .6 1 sittings per dentist. For fluoridated com m unities, the c o m ­ parable figures were 7 ,6 0 3 sittings, 133 dentists, and 5 7 .1 7 sittings per dentist.) T h is is 12.6 and 12.3 sittings per dentist daily in fluoride-deficient and fluoridated com m unities respectively; these figures are considerably low er than the m edians for daily sittings per dentist that w ere derived from th e estim ates o f the dentists. ■ D entists’ incom e: D esp ite th e greater direct and indirect effort by dentists in fluoride-deficient com m unities, m edian incom es o f dentists were higher in fluoridated com m unities. A ccording to the dentists’ report, m edian gross in com e from p ractice in fluoridated com m unities during ca len ­ dar 1965 was $ 3 5 ,9 0 5 , 6.4% m ore than the c o m ­ parable m edian o f $ 3 3 ,7 5 0 in fluoride-deficient com m unities. D a ta were requested for calendar 1965, because at the tim e o f com pilation o f the survey (January-February 1967), m any dentists h ad not yet com puted their 1966 incom e. In com e inform ation w as obtained from 105 o f the 144 dentists in fluoridated com m unities and 9 6 o f the 134 dentists in fluoride-deficient co m ­ m unities (73% and 72% respectively). T h e re­ fusals included som e for w hom the question was not applicable— those who had not been in prac­ tice during 1965, or not in practice for a full year. C onsistent with the m ore in tensive use o f in ­ direct effort, m edian overhead w as higher in the fluoride-deficient com m unities ($ 1 6 ,7 5 0 ) than in the fluoridated com m unities, ($ 1 6 ,1 3 0 ). T h ese

Table 7 ■ Dentists’ output in fluoridated and fluoride-deficient com munities, 1966.______________________________________________________________________ O utput Median annual patient sittings Median no. annual patients Estimated median sittings per patient* Median daily (working day) patient sittings Median duration (min) per patient sitting

F luoridated com m u nities

F luoride-deficient com m unities

3,000 1,016 2.95

3,125 1,084 2.88

14.22

15.34

34 6

33.8

‘ Estimated by dividing median annual patient sittings by m edian num ber of patients

3 6 2 ■ JADA, Vol. 84, February 1972

figures represented an average overhead o f 4 9 .6 % in the fluoride-deficient com m unities, but on ly 4 4 .6 % in the fluoridated com m unities. B ecau se o f this higher overhead in the fluorided eficien t com m unities, th e differential between th e tw o sets o f com m unities in net incom e w as m uch greater than the differential in gross in ­ com e. M edian net in com e in the fluoridated com m unities w as $ 1 9 ,8 7 5 , about a sixth (1 6 .9 % ) m ore than the com parable $ 17,000 in the fluoridedeficient com m unities. B ased on responses to the direct question, “ W hat percent o f your gross in ­ co m e in 1965 w as overhead?” the m edian over­ h ead in the fluoridated com m unities w as 43.4% and in the fluoride-deficient towns, 4 4 .9 % . T h e differential thus obtained is sim ilar in d irec­ tion to th e aforem entioned figures, although smaller. A ccording to The 1965 Survey o f D en ­ tal Practice ,18 the m edian net incom e o f n o n ­ salaried dentists in Illinois, Indiana, and O h io in 1964 w as $ 1 5 ,9 8 3 , $ 1 6 ,0 5 0 , and $ 1 8 ,9 1 7 , respectively. H ow ever, their ratios o f net to gross incom es, based on m ean averages, were 5 5 .9 % , 5 6 .5 % , and 5 4 .8 % , respectively, so that their overhead, calculated on this basis, ranged from 4 3 .5 % to 4 5 .2 % . T h is sam e pattern— low er m edian annual gross and net in com es and higher overhead, both in absolute term s and a percent o f gross in the flu or­ id e-deficient com m unities— also w as found in each o f the three larger pairs o f com m unities. Similarly, th e direction o f these differentials w as generally confirm ed by a later replication o f this aspect o f the present survey, in which data for calendar 1967 w ere requested; however, th e m a g ­ n itu de o f the differential in m edian net in com e w as found to be smaller. T h is later survey o f d en ­ tists participating in the original survey w as c o n ­ ducted by m ail and elicited a 67 % response from the fluoridated com m unities, and 54% from the fluoride-deficient com m unities. T h e results were: In fluoridated com m unities, m edian gross in com e w as $ 4 5 ,6 8 0 ; in fluoride-deficient com m unities, $ 4 3 ,0 0 0 ; the excess for m edian gross in com es in fluoridated areas w as 6 .2 % . O verhead in fluori­ dated areas w as $ 2 1 ,0 2 0 (46% ); in fluoridedeficient com m unities, $ 2 0 ,0 0 0 (4 6 .5 % ); excess for overhead in fluoridated com m unities, 5 .1 % . T h e m edian net in com e in fluoridated com m un ­ ities w as $ 2 4 ,6 6 0 ; in fluoride-deficient com m un ­ ities, $ 2 3 ,0 0 0 ; th e excess in m edian net incom es in fluoridated areas w as 7 .2 % . T h e follow ing points are worth noting: T h e differential in m ed ­ ian n et in com e persists, although its m agnitude

is smaller; the differential in m edian gross in ­ com es persists at about th e sam e relative m agni­ tude; th e differential in overhead as a percent o f gross incom e is m uch narrower than formerly, and the direction o f th e differential in dollar am ounts o f overhead is reversed. T h e potentially biasing effects o f the slightly larger number o f specialists in the fluoridated com m unities were rem oved in a separate analysis o f the incom es o f general practitioners. T his show ed m edian net in com es o f $ 1 8 ,8 7 8 in fluor­ idated com m unities and $ 1 6 ,6 6 2 in the fluoridedeficient com m unities, an excess o f 13.3% in the former. C om parison o f th e in com e distribution (Table 8 ) shows slightly m ore o v er -$ 3 0 ,0 0 0 incom es in the fluoridated com m unities and m ore practitioners in the $ 1 2 ,5 0 0 to $ 1 7 ,5 0 0 and $ 2 0 ,0 0 0 to $ 2 2 ,5 0 0 in com e categories in the fluoride-deficient com m unities. A lthough the actual number o f dentists involved in th ese ca te­ gories is sm all, it is sufficient to account for the differentials in the m edian incom es for both all dentists and general practitioners. N et incom es o f general practitioners w ere cross-tabulated by the various item s that w ere used in th e present survey: characteristics o f the dentists and their practices, direct and indirect effort, and output. In general, with on ly m inor exceptions (probably because o f the small num ber involved), the d if­ ferentials persisted. On the assum ption that the differentials in in com e m ay h ave reflected differences in fees charged in the two sets o f com m unities, a fee survey was carried out in 1968. That survey show ed a rem arkable sim ilarity in fees by type o f service provided in the tw o sets o f com m unities. T h e m eans charged for each service in n o instance differed by m ore than 3% or 4 % , and th e direc­ tion o f these differences w as not at all consistent. ■ Characteristics o f patients and nature o f d en ­ tal treatment: O ne o f the m ore significant results that em erged from the study w as the noticeable sim ilarity in age com position o f th e tw o patientpopulations (T able 9). T h e m edian age o f p a ­ tients in the fluoridated com m unities w as esti­ m ated at 29.4, com pared with 2 8 .5 years o f age in the fluoride-deficient com m unities. Children under 16 years o f age constituted, as estim ated, 2 6.5% o f all patients in the fluoridated com m u n i­ ties and alm ost 27% in the fluoride-deficient com m unities. T he contention that children in fluoridated com m unities see a dentist for the first tim e at a later age com pared with those in fluorideDouglas—others: FLUORIDATION AND DENTAL MANPOWER ■ 363

Table 8 ■ Net incom e g ro u p s o f all d e n tists and g e neral p ra c titio n e rs , (in percent), in flu o rid a te d a nd flu o rid e -d e fic ie n t co m m u n itie s, 1965. F luoride-deficient

Fluoridated Income groups (dollars)

A ll dentists 7,500 7,501 - 10,000 10.001 - 12,500 12.501 - 15,000 15.001 - 17,500 17.501 - 2 0 ,0 0 0 20.001 - 22,500 22.501 — 25,000 25.001 - 2 7 ,5 0 0 27.501 - 3 0 ,0 0 0 30,001+ Median incom e

All dentists

General practitioners

100 0 (N=105) 9.5 8.6 5.7 7.6 9.5 9.5 86 11 4 7.6 6.7 15.3 $19,875

(N=92) 10.9 9.8 5.4 8.7 9.8 9.8 98 13.0 5.4 6.5 10.9 $18,878

100 0

All dentists

100.0

G eneral practitioners

100.0

(N=96) (N=90) 7.3 7.8 7.3 7.8 8.3 8.9 14.6 14.4 15.6 16.7 8.3 5.6 12.5 12.2 6.3 5.6 4.2 4.4 8.3 8.9 7.3 7.8 $17,000___________ $16,662

Table 9 ■ Age group* of patients in fluoridated and fluo rid e-de ficie nt communities, 1966.t Fluoridated com m unities

Age group

All ages Children 1-5 6-10 11-15 Adults 16-20 21-35 36-50 51-60 61-70 71 + Median age

F luoride-deficient com m unities

No.

%

No.

%

7,603 2,015 362 862 791 5,588 793 1,733 1,756 729 379 198 29.4

100.00 26 50 4.76 11.34 10.40 73.50 104 22.8 23.1 9.6 5.0 2.6

7,209 1,944 280 864 800 5,265 783 1,729 1,587 706 317 143 28.5

100.00 26.97 3.88 11.99 11.10 73.03 10.86 23.98 22.01 9.80 4.40 1.98

'Estim ated by procedures discussed in text. tW eek of Oct 17 to 22, 1966.

deficient com m unities m ay not be true. T h ese proportions and the m edians represent estim ates, as a large proportion o f the patient-records in both sets o f com m unities did not contain su fficien t­ ly p recise inform ation about p atient-age to be u sable for the present survey. T h is applied to 3 ,5 9 8 patients’ records in the fluoridated com m u n ­ ities, 4 8 .6 4 % o f the total o f 7 ,6 0 3 records, and 1 ,5 9 6 records in the fluoride-deficient com m u n ­ ities, 22.13% o f the total o f 7 ,2 0 9 . For all records except 2% in the fluoridated and less than 1% in the fluoride-deficient com m unities, it w as p ossib le to determ ine whether th e patient w as an adult or a child, either from inform ation on the record or from personal know ledge o f th e d en ­ tist or an o ffic e em ployee. “C hildren” w ere c la s­ sified as under the age o f 16 and distributed in accordance with the proportion o f th ose with known age, and a sim ilar procedure was follow ed for “ adults.” T h e unit o f dental service, as distinct from a patient sitting or a visit, was developed as a m ea ­ surem ent o f th e nature o f dental treatm ent in the tw o sets o f com m unities. Each service represents 364 ■ JADA, Vol. 84, February 1972

a unit o f work, as nearly as it is p o ssib le to define it; on e visit or sitting often includes m ore than o n e service or unit o f work. T h e follow ing are exam ples o f procedures d efined as a service: each restoration to a tooth perform ed at a sitting regardless o f the num ber o f surfaces restored on each tooth; each tooth extracted; each sitting for a preparation, fitting, or adjustment o f a fixed or rem ovable prosthesis; all radiographs taken at o n e sitting; and every other separate procedure, including such m iscellan eou s services as all im ­ pressions taken at o n e sitting, a postsurgical visit, or occlusal equilibration. A s defined, the 7 ,6 0 3 sittings for which data w ere ob tain ed in the fluor­ idated com m unities resulted in the provision o f 10,953 services; the com parable figures in the fluoride-deficient com m unities w ere 7 ,2 0 9 sit­ tings and 10,370 services. In each instance, the average w as 1.44 services per sitting. D ental treatm ent provided to patients, c o n ­ sidered in term s o f services, was noticeably sim i­ lar in both sets o f com m unities (T able 10). R e s ­ torations accounted for m ore than tw o fifths o f all services; about three quarters o f th ese w ere

Table 10 ■ Nature

of

dental

treatm ent

provided

in

fluoridated

and

fluoride-deficient

communities, 1966.* Fluoridated com m unities

Dental treatm ent (services)

All treatm ents Restorations Deciduous teeth f Permanent teeth f Gold inlays, gold crowns, and porcelain and acrylic ja ckets O ther restorations Extractions Deciduous teeth Permanent teeth First permanent molars T hird perm anent m olars and supernum erary teeth Prophylaxes Radiographs Prostheses Fixed bridges Partial dentures Complete dentures Specialty treatment Topical fluoride application Surgery sittings including im pactions O ther and ill-defined treatm ent

F luoride-deficient com m unities

10,953 4,512 624 3,402

100.0 41.2 5,7 31.1

10,370 4,367 •449 3,454

100.0 42.2 4.4 33.3

316 170 1,641 255 999 196

2.9 1.5 14.9 2.3 9.1 18

314 15 0 1,570 251 977 205

3.0 1.5 15.1 2.4 9.4 2.0

191 1,624 1,269 488 83 174 231 401 163 117 738

1.7 14.8 11.5 4.5 0.8 1.6 2.1 3.7 1.5 1.1 6.8

137 1,581 1,137 483 70 126 287 215 107 82 828

1.3 15.2 10.9 4.7 0.7 1.2 2.8 2.0 1.0 0.8 8.0

'W eek o f O ct 17 to 22, 1966. tA m algam , cement, and plastic

restorations to perm anent teeth. Prophylaxes and extractions each accounted for about 15% o f all services in each set o f com m unities, and rad io­ graphs for about another 11 % in both. Prostheses account for less than 5% o f all services in each set o f com m unities. T w o fairly substantial d iffer­ en ces in th ese figures should be noted. Specialty treatm ent (orthodontic, endodontic, and p eriod on ­ tal treatm ent provided in general p ractitioners’ o ffices) constituted a larger proportion (3 .7 % ) o f all treatm ents in fluoridated com m unities than in fluoride-deficient com m unities (2 .0 % ). T h is m ay account for som e part o f the otherw ise u n ­ exp lain ed in com e differential betw een th e tw o sets o f com m unities. A lso restorations o f d ecid u ­ o u s teeth constituted 5.7% o f th e services in flu or­ idated com m unities, but on ly 4 .4 1 % in the fluor­ id e-deficient com m unities. T h e greater num ber o f restorations perform ed on deciduous teeth in the fluoridated com m unities m ay result from the larger num ber o f these teeth retained and, there­ fore, available for treatm ent in the fluoridated com m unities. T h ese data have been expressed in term s o f the proportionate distribution o f th e various treat­ m ents provided by dentists. O n a per-population basis, how ever, a som ew hat different relationship em erges. D en tists in fluoridated com m unities serve m uch larger p opu lations than their c o l­ leagues in fluoride-deficient com m unities. T h ere­ fore, th e rates for alm ost all o f the various c a te ­ gories o f treatm ent per population are larger in fluoride-deficient com m unities. T h is is shown in T ab le 11 for som e selected categories o f treat­

m ent. For exam ple, the rate per 1 0 0 ,0 0 0 p o p u la ­ tion for restorations involving g o ld inlays, gold crowns, or porcelain or acrylic jackets in the fluor­ ide-deficient com m unities, 7 ,8 4 2 , exceeds the rate, 6 ,6 3 8 , in fluoridated com m unities by 18% . T h e rate is 17% higher for extractions o f d ecidu ­ ous teeth; o n ly in restorations o f deciduous teeth is the rate low er (1 4 % ) in fluoride-deficient c o m ­ m unities, probably because o f the larger num ber o f deciduous teeth retained by patients.

T h e P u eblo-B eaum on t survey Supplem entary data were obtained from 4 2 d en ­ tists in active p ractice in Pueblo, C olo, with n a t­ urally fluoridated water and 45 in Beaum ont, Tex, with fluoride-deficient water. For this study, the com parability o f these tw o cities was c o n ­ sidered lim ited because Beaum ont is th e center o f a m uch larger m etropolitan area than is Pueblo; dental practice in Beaum ont w as considered to b e m uch m ore a “ dow ntow n” or “central business district” type o f practice. O n e aspect o f th ese data is directly relevant to the present discussion and w ill be considered here. Patient data covering a tw o-w eek period, Sept 16 to 29, 1968, w ere obtained from the records o f 4 0 dentists, excluding orthodontists, in active p ractice in Pueblo. In teleph one in ter­ v iew s (which w ere not done in the m idwestern com m unities) with th e patients, inform ation was obtained about their birthplace and p la ce o f resiDouglas—others: FLUORIDATION AND DENTAL MANPOWER ■ 365

Table 11 ■ Selected c a te g o rie s o f d e n ta l tre a tm e n t p e r 100,000 p o p u la tio n p rovided in flu o rid a te d and flu o rid e -d e fic ie n t c o m m u n itie s , 1966.* Services per 100,000 population Selected categories of dental treatm ent (services)

Fluoridated com m unities

F luoride-deficient com m unities

% excess of fluorid e-d eficien t

13,110 71,476 6,638

11,214 86,267 7,842

-14

5,357 20,989

6,268 24,401

17 16

Restorations Deciduous teeth f Permanent teeth f G old inlays, gold crowns, and porcelain and acrylic jackets Extractions Deciduous teeth Permanent teeth (excluding first and third permanent molars) First permanent molars

21 18

*Week of Oct 17 to 22, 1966. f Amalgam, cement, and plastic.

ture o f dental treatm ent provided to th ese p a ­ tients, expressed in term s o f services (as in T ab le 10), but with the patients grouped by age, under 35 years o f age and 35 years o f age and over. Perhaps the major contrast in th ese data, and o n e not evident in the earlier data, is am ong the younger patients; those from fluoridated areas were m ore lik ely to h ave been treated for res­ torations, whereas those from fluoride-deficient areas were m ore likely to be treated for extrac­ tions. Interestingly, this w as true for deciduous and perm anent teeth alike. T h is pattern was slightly reversed among patients 35 years o f age and over, but the differences w ere sm all. P ro ­ phylaxes w ere done som ew hat m ore frequently for patients from fluoridated areas, w hereas p ros­ theses were m ore com m on am ong persons from fluoride-deficient com m unities.

dence during their first ten years o f life. It was p ossib le to classify 3,390 patients, 86% o f all, patients for whom treatm ent data w ere obtained, as having an entirely, or at least, clearly p re­ dom inantly “ fluoridated” or “fluoride-deficient” background. (T he number 3 ,390 refers to sittings and, therefore, som e degree o f duplication o f patients is in volved because som e patients had m ore than on e sitting during the tw o-w eek p er­ iod .) T h e patients w ere about equally grouped by background: 1,659 w ere from fluoridated com m unities and 1,731 were from fluorid e-de­ ficient areas. B ecause a large proportion o f p a ­ tients w ere born and reared in fluoridated Pueblo, and these w ere largely younger persons, patients from fluoridated com m unities were generally younger than their counterparts from fluoridedeficient com m unities. T ab le 12 shows th e n a ­

Table 12 ■ Nature of dental treatment for patients from fluoridated and fluoride-deficient com munities, by age, Sept 16 to 29, 1968.

in % Under age 35 Dental treatm ent (services) All treatments Restorations Deciduous teeth* Permanent teeth* Gold inlays, gold crowns, and porcelain and acrylic jackets O ther restorations Extractions Deciduous teeth Permanent teeth First perm anent molars Third permanent m olars and supernum erary teeth Prophylaxes Radiographs Prostheses Bridges Dentures Specialty treatment (in GP office) Topical fluoride applications Surgery sittings (including im pactions) Other treatments 'Am algam , cement, and plastic.

366 ■ JADA, Vol. 84, February 1972

35 and over

Pueblo, Colo

Beaum ont, Tex

Pueblo, Colo

Beaum ont, Tex

100.0 33.8 6.7 21 4

100.0 27.5 5.8 18.5

100.0 21.9

100 0 23.3

16.9

18.5

1.5 4.2 13.1 56 4.6 0.8

0.7 2.5 23.3 84 10.2 1.7

3.3 1.7 19.3 0.4 15.6 0.8

3.4 1.4 17.2 0.1 13.2 2.3

2.1 14.7 23.0 1.8 0.7 1,1

30 12.1 23.5 3.5 1.0 25

2.5 20.7 13.3 8.3 2.1 6.2

1.6 15.4 15.3 10.8 1.9 8.9

3.5

3.2

1.5

2.3

1 1'

0.3

1.0 8.0

1.9 4.7

02 1.1 13.8

0.3 15 1

S u m m ary and discussion T h is study, a com parison o f dental p ractice in naturally fluoridated and fluoride-deficient c o m ­ m unities, has shown that dentists in fluoridated com m unities serve a substantially larger patient load than dentists in fluoride-deficient com m un ­ ities— 14.5% larger and perhaps as much as d oub le that figure when considered apart from th e bias o f migration. N evertheless, the ch arac­ teristics o f the dentists and som e aspects o f their practices— age o f dentists, years in practice, e x ­ tent o f specialization, and type o f practice (that is, solo versus partnership or associateship)— appear to be virtually unaffected by fluoridation. D en tists in fluoride-deficient com m unities appear to be busier and certainly invest m ore direct (hours and days per week o f their own labor) and indirect (number o f operatories, use o f auxiliary personnel, and so on) effort in their practices. T heir output, as a result, is also greater, that is, num ber o f patients seen and num ber o f “ sittings.” D en tists in fluoridated com m unities, in contrast, feel less overw orked and spend on the average slightly m ore tim e on each patient sitting. D esp ite their less in tensive effort, dentists in fluoridated com m unities earned som ew hat larger gross and, especially, net incom es in 1965, even with degree o f specialization, effort, and so on, h eld constant. T h e differential persisted, although it w as reduced considerably in m agnitude, in a survey o f the dentists’ 1967 incom e. D ata on the nature o f the treatm ent provided in the two sets o f com m unities revealed rem arkable sim ilarities cou p led with on ly m inor differences. N o e x ­ planation em erged for the incom e differential. A pparently fluoridation does not, in the short run, decidedly affect the dentists’ incom es, fees, and the nature o f treatm ent to any significant degree. T h e unm et need for dental care continues to be enorm ous, in spite o f fluoridation. F luoridation does appear to help extend the existing p ool o f dental m anpower to cover a substantially larger population. It is p ossib le that it m ay have a som ew hat retarding effect on the extension o f auxiliary personnel into dental practice. A lthough there rem ains no doubt about the efficacy o f fluoridation as a preventive m ea ­ sure against dental caries, the tim e has apparently not yet arrived when it is causing decided changes in the pattern o f dental practice.

Doctor Douglas is professor o f .com m unity dentistry, U ni­ ve rsity o f Illin o is College o f Dentistry, and professor o f pre­ ventive m edicine and co m m u n ity health, U niversity o f lllin o is C o lle g e o f Medicine. His address i s 841 Castlew oodTer­ race, Chicago, 60640. Doctor W allace is professor o f dental radiology, U niversity o f Illin o is Col lege o f Dentistry, Chicago. Doctor Lerner is professor o f m edical care and hospitals, Johns Hopkins University School o f Hygiene and Public Health, Baltim ore. Miss Coppersm ith is fie ld supervisor, flu o rid a tio n research project, U niversity o f Illin o is College of Dentistry, Chicago. 1. Blayney, J.R., and H ill, I.N. Fluorine and dental caries. JADA 74:233 (special issue) Jan 1967. 2. Campbell, I.R. Role o f flu o rid e in p u b lic health: th e soundness of flu o rid a tio n in com m unal water supplies, a selected bibliography. C in cin n a ti, U niversity o f C incinnati, 1963. 3. Englander, H.R.; dePalma, R.; and Kesel, R.G. The Aurora-Rockford, Illin o is study 1—effe cts of w ater having n a tura lly occurring flu o rid e on dental health of young adults. JADA 65:614 Nov 1962. 4. Barber, T.K. Concept o f preventive orthodontics. J Dent C h ild 33:75 March 1966. 5. Englander, H.R. Dental caries experience o f teen-aged ch ild ren who consumed flu o rid a te d or flu o rid e -d e ficie n t water co n tinuously from birth. In te rn a t Dent J 14:497 Dec 1964. 6. Englander, H.R., and Wallace, D.A. E ffects o f n aturally flu o rid a te d water on dental caries in adults. Pub Health Re­ ports 77:887 Oct 1962. 7. Russell, A.L., and Elvove, E. Domestic w ater and den­ tal caries, VII. A study o f fluoride-dental caries relationship in an adult population. Pub Health Reports 66:1389 Oct 26, 1951. 8. Ast, D., and others. T im e and cost fa cto rs to provide regular, periodic dental care for c h ild re n in a flu o rid a te d and nonfluoridated area. Amer J Pub Health 55:811 June 1965. 9. Ast, D.B., and others. T im e and cost fa cto rs to provide regular, periodic dental care for ch ild ren in a flu o rid a te d an d no n fluoridatedarea: fin a l report. JADA80:770 April 1970. 10. Denby, G.C., and H ollis, M.J. E ffect o f flu o rid a tio n on a dental health pu b lic programme. New Zeal Dent J 62:32 Jan 1966. 11. Blayney, J.R. Economy o f water flu o rid a tio n . JADA 65:595 Nov 1962. 12. M itchell, G.E. The false economy o f dental neglect. U S P H S p u b n o . 1178. Washington, DC, G overnm ent P rinting O ffice, p 18. 13. S triffle r, D.F. R elationship o f endemic flu o rid e s to th e need and demand fo r dental services in New Mexico. New Mexico Dent J 7:13 Aug 1957. 14. M uhler, J.C. Challenge o f preventive dentistry. JADA 66:199 Feb 1963. 15. Terhune, R.C., and M uhler, J.C. In flu e n ce o f com ­ m unal flu o rid a tio n upon dental practice. J Dent C h ild 34: 228 Ju ly 1967. 16. Douglas, B.L., and Coppersm ith, S.B. Im pact of water flu o rid a tio n on dental practice: a review of th e literature. New York Dent J 31:439 Dec 1965. 17. Lerner, M., and others. M ethodology in a study o f the im p act o f water flu o rid a tio n on dental practice. Proceedings o f th e American S tatistica l Association, Social S ta tistics Section, 1968, p 210. 18. Bureau o f Economic Research and S tatistics. The 1965 survey o f dental practice. Chicago, Am erican Dental Association, 1966. 19. Bureau o f Economic Research and S tatistics. The 1968 survey o f dental practice. Chicago, Am erican Dental Association, 1969.

Douglas—others: FLUORIDATION AND DENTAL MANPOWER ■ 367