* Cirurgião Dentista, Especialista em Ortorontia ** Faculdade de Odontologia, "Campus" de Araçatuba, São Paulo, Brasil **** Department of Orthodontics, University of the Witwatersrand, Johannesburg.

Key words: cephalometrics; sambaquis constructor man; Brazil

The "Sambaquis Constructor Man" has been identified as a distinct prehistoric group who lived along the southeastern Brazilian shore. A representative sample of 29 "Sambaquis" skulls were obtained and subjected to lateral cephalometry. Several analyses were undertaken and the means of the various measurements compared of reference norms. In general, the results indicated that the Sambaquis Man presented harmonious cranio-dento-facial proportions which largely meet present-day concepts of aesthetics and functional balance.

Die "Sambaquis Bouman" word erken as 'n duidelik onderskeibare prehistoriese groep wat langs die Suidoos Braziliaanse kus gewoon het. 'n Verteenwoordigende monster van 29 "Sambaquis"-skedels is verkry en daar is 'n laterale kefalometriese ondersoek daarop gedoen. Verskeie ontledings is gedoen en die gemiddeldes van die verskillende metings is met standaard norme vergelyk. Oor die algemeen het die ondersoek getoon dat die Sambaquis Man harmoniese skedeltand-gelaat-afmetings besit wat grotendeels aan hedendaagse begrippe van estetika en funksionele balans beantwoord.

Research on prehistoric Brazilian human populations has been hampered by a relative paucity of specimens. The most significant archeological sites have been the area of Lagoa Santa, in the State of Minas Gerais, and the Brazilian seashore. It is from the latter that the human remains referred to as "The Man from Sambaquis" (Lacerda, 1885) have been unearthed.

Although the anthropological entity of the "Sambaquis Man" is not entirely proven, it is strongly supported by the craniometric analysis, the general morphologic characteristics and the frequency and distribution of identifiable specimens found along the coast of Brazil (Mello e Alvim, 1978). The "Sambaquis Man" was different from and less homogenous than the "Man from Lagoa Santa" (Mello e Alvim, 1963, 1972) although the habitat was shared. Von Eickstedt (l934) classified the "Sambaquis Man" as part of the Lagiden coastal types whilst Imbelloni (l937, 1938, 1953) believed they constituted the main part of the Fuégidos.

The staple diet of this Indian micro-group was molluscs and fish, supplemented by gathered vegetable-, and hunted meat. Over thousands of years the accumulation of food residue, mainly mollusc shells. formed oval hillocks, subsequently called "Sambaquis" or "Concheiras" (shell mounds) - which led to the label "Sambaquis Constructor Man'' (Mello e Alvin, Viera and Cheuiche, 1975). Radioactive dating of the C" content in the residues has indicated that the Sambaquis Constructors survived from 6 500 BC. The Sambaquis (shell mounds) are found along the coast down to the Rio Grande De Sul, and each may be up to 30 metres in height by 400 metres in length (Rohr, 1959; Mello e Alvim, Viera and Cheuiche, 1975). The mollusc shells are deposited in layers separated by charcoal beds which demonstrate signs of human habitation and include burial sites.

Anthropological evaluation indicates that the Sambaquis Constructors were well built and evidently capable of intense physical labour, for the muscle attachment ridges on the long bones are pronounced. Skeletal sexual differentiation is well defined, enabling determination of an average height of 1,6 m for males and of 1,5 m for females. The skulls are comparatively large and have sloping foreheads leading to wide faces with accentuated orbits in most specimens. The neurocranial capacity, verified using Lee-Pearson's formula (Lee and Pearson, 1901) was considerable, and ranged from 1,474 cm 3 to 1,632 cm 3 in males and from 1,240 CM3 to 1,354 cm 3 in females (Mello e Alvim, 1972).

The heavy masticatory effort involved in chewing hard and abrasive foods is reflected in the strong jaw configuration, with a square gonial angle, and the denslymineralized teeth which show considerable abrasion (Pereira et al, 1972; Pereira and Evans, 1975).

Little, if any work has been published on any cephalometric analyses of prehistoric Brazilian populations, although the literature is replete with papers treating with such studies of various other discrete racial groups (Jacobson and Dreyer, 1956; Murphy and Evans, 1959; Brown and Barrett, 1964; Brown, 1965; Wei, 1968; Machado Filho, 1969; Sadowsky and Jacobson, 1973; Garcia, 1975; Jacobson et al, 1977).

The present study was undertaken to cephalometrically evaluate the configuration of the facial skeleton of, and the disposition of the teeth in, the Sambaquis Constructor Man, and to compare the results with those from previous related studies (e.g. Drummond, 1968).

Twenty-nine "Sambaquis Constructor" skulls (l7 males, 12 females) were selected from the collections housed at the Rio De Janeiro National Museum, the Florianopolis Sambaquis Museum and the Joinville Sambaquis Archaeological Museum. Each of the selected specimens was complete and well-preserved, had an intact sella turcica and retained sufficient teeth to unequivocally establish habitual occlusion.

The skulls were supported in a standard cephalostat by the ear rods and by nylon-foam pieces (Pereira and Mello e Alvim, 1979). From the resulting cephalometric radiographs the craniofacial and dental structures were traced on to acetate paper, and the morphological relationships were examined using the Steiner (l953) and Tweed (l946) analyses, together with Downs (l948) growth axis, S-Gn, and the "Wits" appraisal (Jacobson, 1975, 1976a) (Figs. 1, 2 and 3). In addition, the denture space area and incisor inclinations were assessed using the "dental area diagram" (Jacobson, 1976b) (Fig. 4). Measurements were made using a millimetre rule and a protractor, reading to the nearest O,5 millimetres and O,5 degrees respectively.

The means and standard deviations of the various measurements are recorded in Tables I and 11. Characteristically, the skulls of the Sambaquis Constructors present a relative maxillary protrusion (mean SNA = 84,13'; norm = 82') associated with a comparatively small anterior cranial base length (SN; Fig. 1) cf 69,5 mm (of: Caucasian mean = 74,9 mm; Lengua Indians mean = 66,9 mm; Jacobson et al., 1977). This is a relationship which may be geometrically coordinated, as described by Jacobson (l975).

Several research workers have commented on the variation in cranio-facial skeletal patterns amongst different samples (Baum, 1951; Altemus, 1960; Nanda and Nanda, 1969; Uesato et al, 1978; Hajighadimi, Dougherty and Garakani, 1981). The maxillo-mandibular relationship as assessed by the "ANB" angle, has been used to distinguish between racial groups (Jacobson, 1978) and in the present study provides a basis for comparative evaluation. The reference norm value of the ANB angle recommended by Steiner (l953) is 2'. The comparatively larger ANB angle of the Sambaquis (mean = 4,5') appears to be related to a relative maxillary protrusion (mean SNA = 84,13'; norm = 82') whilst the mandibular position, recording a mean SNB value of 80', is at the Steiner norm. lt. may be postulated that the upper incisors are rather upright (mean = 11,2'; norm = 22') in physiological "compensation" for the mild skeletal maxillary protrusion whilst the more normal lower incisor position (mean 23,3'; norm = 25'; mean FMIA = 62,7'; norm = 65') still ensures a harmonious overbite relationship. The interincisal angle is as a consequence large (mean 141,8'; norm 132') and the dental profile remains relatively fiat.

Figure 5 is a composite diagram demonstrating the superimposition of the dentition areas of Caucasoids, South African Bantu and the Sambaquis Constructor Man. The posterior dental height of the present sample was shown to be greater, on average, than that of either the Caucasoid or the South African Bantu populations. The length of the occlusal plane was close to the value recorded in the Caucasoid sample, but shorter than the value seen in the South African Bantu. Palatal plane length was longer in the Sambaquis Constructors, whilst mandibular plane length was longer only for the male sample.

The incisors of the Sambaquis Constructors are more vertically placed than those of the Caucasoid, which in turn are less protrusive than those of the South African Bantu. There is a rather small difference between the lengths C, and C2, associated, not unexpectedly, with a reduced overjet in the Sambaquis sample (Fig. 5).

The combined influence of upright upper incisors together with a slightly prognathic chin lend credence to the deduction that the profile of the Sambaquis Constructor Man was relatively straight (Mello E Alvim, 1978) (Fig. 1). The mean Tweed Triangle measurements (FMA = 25,8'; IMPA = 91,5'; FMIA = 62,7'; Fig. 2) are very close to those reference standards derived from data published by Kowalsky and Walker (l971) (FMA = 25'; IMPA = 90'; FMIA = 65'). This indication of a skeletal pattern which conforms relatively well to present day concepts of a well balanced Caucasian face is lent further support by other ,,vertical" skeletal parameters: SN to GoGn = 3r (norm = 32'); SN to occlusal plane = 18,3' (norm 14'; SN to GN = 70,1 (norm 69').

The sample did record rather large standard deviations for several cephalometric and dental area diagram parameters (Tables I and II). In particular, the incisor measurements appear to demonstrate this variability, but, whithin one standard deviation, the upper incisors still record a position more upright than the reference norms.

The antero-posterior relations of the mandible and maxilla (ANB angle) of the Sambaquis Constructor Man are slightly more devergent than the reference norms applicable to modern Caucasoid populations. A dental compensation, in the form of upright upper incisors, together with an indication that the vertical proportions are in harmony, make it conceivable to assume well-balanced and straight profiles for the Sambaquis, producing faces not dissimilar to present day concepts of pleasing aesthetics.

We are grateful to the administrations of the Museu Nacional do Rio de Janeiro, the Museu Arqueológico de Joinville, and the Museu do Homem do Sambaqui de Florianópolis; to Professor Marilia C. de Mello e Alvím, Professor Alfonso Inhof, and Father J. Alfredo Rohr; to the Chief of the Department of Orthodontics of the Universidade Federal do Rio de Janeiro and the Chief of the Department of Orthodontics of the Universidade Federal de Santa Catarina; to Professor Doctor José Edimo Martins, Dr. José Tarcisio Soares and Professor Sandro de Mascarenhas; and especially to the Conselho Nacional de Pesquisa for financial support of this research.

The soft tissue profile was subjectively conceived based on anthropological predictions (Mello e Aivini, 1978).

Fig. 2 - The Tweed Triangle, illustrated on the tracing from skull No. 9 (female).

Fotografias de crânios de Sambaquis