Markku Larmas

Turku sugar studies VIII: Principal microbiological findings

The possible qualitative and/or quantitative alterations in the proportions of cultivable groups of oral microorganisms were analysed during a clinical trial involving the consumption of fructose (F) or xylitol (X) in comparison to sucrose (S). Supragingival plaque samples and paraffin-stimulated saliva were collected from 115 subjects. The samples were dispersed by sonication, diluted stepwise, plated on blood sugar, Mac Leod agar, Mac Concey agar, Rogosa S.L. agar, and Sabouraud agar plates and incubated anerobically and/or aerobically. The number of the total colony forming units (CFU) on blood agar plates in anaerobic incubation was about 1-3 X 10(9)/ml saliva and 1-4 X 10(8)/mg plaque and in aerobic respectively 5-18 X 10(8)/ml saliva and 10(8)/mg plaque. The total CFU on Mac Leod agar was of a similar order of magnitude. The variation between subjects and consecutive determinations was of a similar order of magnitude. The variation between subjects and consecutive determinations was relatively large. The arithmetic mean of the total CFU on Mac Concey agar was about 1-5 X 10(5)/ml saliva, on Rogosa S.L. agar 6-130 X 10(3)/ml saliva and on Sabouraud about 1-2 X 10(3)ml saliva, all in aerobic incubations. Replacement of dietary sucrose with xylitol did not affect the proportion of major microbial categories in saliva or dental plaque. The percentage of typical streptococcal colonies on blood agar was of a similar order of magnitude (about 60-70%) during the diets. The arithmetic and geometric means of the total CFU values on Rogosa and Sabouraud agar plates were significantly lower in the X-group than in the S- or F-groups after a diet period of some months. It was thought that the reason for the reduction of acidogenic and aciduric oral flora in the X-group was partly due to the fact that xylitol is generally not metabolized by these microorganisms.

A histochemical study of arylaminopeptidases and alkaline phosphatases in sound and carious human teeth

Fresh, undecalcified sections (of 6—20 μm) from intact or carious human teeth as well as teeth with different types of pulpal inflammation were cut in a heavy duty microtome at —20° C. Scotch tape was used to stabilize the teeth during sectioning. The localization of arylaminopeptidases (EC 3.4.1.) and alkaline phosphatase (EC 3.1.3.1.) was demonstrated histochemically using an azo dye principle. The teeth were also examined by microradiography. No arylaminopeptidase activity was normally observed in intact teeth by the histochemical method. In carious teeth, however, this enzyme activity could be localized in the dentinal tubules of the carious lesion, whereas sound dentin, predentin and pulp did not reveal any activity. The inflamed part of the pulp was observed to reveal marked arylaminopeptidase activity. Alkaline phosphatase was observed to be localized mainly in the predentin layer and in the subodontoblastic layer of the pulp and additionally in the cementum and in the remaining parts of the period...

Enzymes in Carious Human Dentine a Histochemical Akd Biochemical Study

Human carious dentine was excavated in situ or obtained from extracted teeth and sound dentine samples were prepared from extracted teeth. the dentine samples were cut in a cry-ostat for histochemical studies or crushed in a mortar for biochemical analyzes. Hydrolysis of ntimerous naphtol deriwtes was histochemically detected in dental plaque and in the tubules of carious dentine, indicating the occurrence of the following hydrolases in the structures: arylaniinopeptidases (EC 3.4.1.1.–3.4.1.3.). nonspecific esterases (EC 3.1.1.), alkaline phos-phatase (EC 3.1.3.1.), acid phosphatase (3.1.3.2.), ATPase (3.6.1.3.), phosphoamidase (EC 3.9.1.1.), α-glucosidase (EC 3.2.1.20.), β-glucosidase (EC 3.2.1.21.), βgalactosidase (EC 3.2.1.23.), β-glucuronidase (EC 3.2.1.31.), and arylsulphatase (EC 3.1.6.1.). Aryliminopeptidase (EC 3.4.1.4.) was observed only in dental plaque. Chitobiase activity (EC 3.2.1.29.) was not denionstrahle in any structures. None of these enzyme activities was histochemically demonstrable i...

Histoehemical Studies on Enzymes Acting on Glycosyl Compounds, Phosphoryl-Containing Anhydrides and Phosphoamides in Human Carious Dentine

Fresh, undecalcified sections from (1) in situ excavated carious dentine or from (2) specimens with carious and sound dentine from extracted human teeth were cut in a cryostat and the localization of various hydrolytic enzymes demonstrated histochemically. It was observed that the hydrolysis of β-glucuronidase, α-glucosidase, β-glucosidase, β-galactosidase, ATPase, and phosphoamidase substrates could be demonstrated (a) in dental plaque, (b) in the superficial necrotic layer and in the infected zone of carious dentine, and (c) also in the decalcified carious dentine, where Gram staining revealed no microorganisms. Additionally, the hydrolysis of β-glucuronidase and α-glucosidase substrates could be observed (d) in the predentine layer. No hydrolysis of chitobiase substrate could be observed in any zone of carious dentine, nor any of the substrates in normal sound dentine. These findings were thought to further map the catabolic events during the propagation of dentine caries, especially in the enzymic deg...

Quantitative Study of the Arylaminopeptidase Activity in Normal and Altered States of Human Dentine

Fresh carious and non-carious human dentine was crushed and the α-aminoacylpeptide hydrolase activity (EC 3.4.11) was quantitatively measured using N -L-aminoacyl-2-napthylamines of

Insufficiency of Currently used Dental Indices in Epidemiology

The World Health Organization (WHO) classifies oral diseases in two different ways: officially dental caries (K02) and gingivitis as well periodontal diseases (K.05) are diseases in the digestive system. In epidemiological surveys the so-called DMF-index values (D= decayed or M= missing or F= filled tooth/surface) are used in determining past and present caries experience and the Community Periodontal Index (CPI) of WHO is used for the region around the teeth. Prevalence may be defined as the proportion of a population that has a disease at a specific point in time. In epidemiology, a subjectspecific approach is the only accepted practice which means that a patient has one or multiple diseases, the rest of the population being healthy. A certain “cut-off” value normally differentiates the healthy subjects from diseased ones. In oral epidemiology the index values are used to determine the “seriousness” of the oral diseases. Calibrated dentists/examiners may be educated in recording dental caries and attachment loss exactly at a high level of precision but unless these scientific recordings are “diagnoses”, the observations represent disease detections and assessments only without providing any prevalence or incidence values of oral diseases. The reason for that is hidden in the fact that the tools for oral health determinations are different from those for the diagnosis of oral diseases by WHO.

Studies on Dog Saliva III. Observations on Enzymes Acting on Ester Bonds and Glycosyl Compounds

Hydrolases acting on ester bonds and glycosyl compounds were studied in the supernatant and sediment fraction of centrifuged dog saliva. When comparing the values obtained to those of man the most interesting deviations were: (1) the lack of a-amylase in dog saliva. (2) the low activity in dog saliva towards 6-bromo-2-naphthyl-α-D-glucoside and glucuronide, (3) the low activity towards 1-naphthyl phosphate at the acidic pH in dog saliva, and (4) the lack of enzymes hydrolyzing 6-bromo-2-naphthyl sulphate in the dog saliva supernatant fraction. The enzymes of centrifuged dog saliva and its sediment were fractionated with Sephadex G-200 and DEAE-cellulose columns. DEAE-cellulose chromatography brought out three enzyme peaks with phosphomonoester hydrolase activity, one of which was active at a wide pH range, one at the acidic side and one at the alkaline side. Two enzyme peaks hydrolyzing 6-bromo-2-naphthyl sulphate were obtained with DEAE-cellulose chromatography from the sediment fraction of dog saliva. T...

Studies on Dog Saliva IV. the Effect of Carbohydrate Diet on the Activity of Some Hydrolytic Enzymes

Six mongrel dogs were reared after weaning on a daily diet composed of (1) raw bovine meat (35 %) containing sucrose (65 %), (2) bovine milk with 10 % sucrose, and (3) water. Five control dogs were kept on a similar diet without sucrose. the experiment was carried out for 260 days. No differences between the groups were observed when comparing the rate of growth, eruption pattern of deciduous and permanent teeth and blood sugar concentration. Hydrolases acting on ester and peptide bonds and glycosyl compounds were studied in the supernatant and sediment fraction of centrifuged dog saliva using altogether 41 different substrates. When comparing the values obtained to those of man the following deviations were observed: the sugar diet did not induce the appearance of salivary α-amylase (EC 3.2.1.1.), proline iminopeptidase (EC 3.4.1.4.) nor acid phosphatase (EC 3.1.3.2.) activity. With a few exceptions, the total hydrolytic enzyme activity in the oral cavity seemed to be constant. However, a fourfold increa...