Glinical Investigator
Clin Investig (1992) 70:735-739
Original ANele
© Springer-Verlag 1992
Caries susceptibility and renal excretion of calcium I. Mosch~n 1, W. Schobersberger 2, L. Klotz 2, E. Jarosch 1, M. Richter 1, and F. Lang 2 1 Universit/itsklinik fiir Zahn-, Mund- und Kieferheilkunde, Universitfit Innsbruck 2 Institut ftir Physiologic der Universit/it Innsbruck
Summary. Clearance studies were performed for 2 days in two groups of age-matched young female volunteers: those with low caries prevalence and those with high caries prevalence. Both groups were kept on a low-calcium diet for 1 week and received 0.5 g calcium at the beginning of the second day. In both groups, glomerular filtration rate, urinary flow rate and renal excretions of sodium, calcium, and phosphate were subject to significant circadian variations. In both groups the administration of calcium led to a significant increase in renal excretion of sodium and calcium and a significant decrease in that of phosphate. On the first day, calcium excretion was significantly greater in those with low caries prevalence than in those with high caries prevalence, pointing to altered calcium homeostasis in this group. Key words: Kidney - Calcium - Phosphate - Sodium - Caries
The crucial event in the development of carious lesions is the demineralization and dissolution of enamel by local acidity as the result of organic acid production by oral bacteria during metabolism of carbohydrates [1]. The local remineralization of the enamel surface, on the other hand, depends in part on the ambient concentrations of calcium and phosphate [16], which may be sensitive to the mineral balance of the individual. Calcium and phosphate balance depends on the interplay of intestinal absorption and renal excretion [5, 11]. Up to now, however, the evidence for a contribution of altered mineral metabolism to the pathophysiology of caries remained equivocal [14]. The present study was performed to test for altered renal calcium and/or phosphate excretion in individuals with a low level of past caries experience. To this end, clearance studies were performed in young women (student nurses) with either low or high caries prevalence subjected to a low-calcium diet.
Methods The 15 individuals volunteering for this study were female student nurses (aged 17-19 years). Seven had low caries prevalence (caries-inactive group), and eight had high caries prevalance (caries-active group). None of the participants reported the use of chlorhexidine digluconate preparations or had a recent history of antibiotics or systemic diseases. An interview was conducted immediately before the clinical examination using a structured questionnaire comprising 110 questions; the interview lasted about 50 min. The questionnaire included questions regarding general health and medication, tobacco use, dietary habits and between-meal habits during an "ordinary week," consumption of sweets, oral hygiene habits, use of fluorides, and dental visits. All intraoral examinations were performed by a single dental examiner. The clinical examination was carried out under optimal clinical conditions and included the parameters described below.
Salivary factors Secretion rate of both unstimulated and paraffinwax stimulated whole saliva was measured as described by Heintze et al. [9]. Buffering capacity of saliva was measured according to Ericson and Bratthall [7] (Dentobuff strip; Orion Diagnostica, Espoo, Finland).
Bacteriologic procedures The levels of salivary Streptococcus mutans and Lactobacillus were determined by the dip-slide technique, using commercial Dentocult SM and LB slides (Orion Diagnostica, Espoo, Finland). [3, 10]. The growth intensity was categorized as recommended by the manufacturer.
736
Oral hygiene
Table 1. Results of clinical examination
The amount of plaque was scored by the Turesky modification of the Quigley-Hein index [18]. A score of 0-5 was assigned to each facial and lingual surface of all available teeth. Before scoring, the plaque was removed with an erythrosine dye solution.
Variable
Gingival inflammation The degree of gingival inflammation was measured by the papilla bleeding index [15], in which gingivitis is scored on a 0-4 scale according to the bleeding from the gingival sulcus after gentle probing.
Caries prevalence All individuals were submitted to professional tooth cleaning prior to caries examination. The criteria according to M611er and Poulson [13] were used. In the front area approximal lesions were assessed with the aid of a fiber light. Four posterior bitewing radiographs were taken of each subject using the long-cone right-angle technique and the Rinn device for correct exposure geometry. Radiographic recordings were carried out blindly according to Gr6ndahl et al. [8]. The D M F - T / D M F - S index was determined by the combination of clinical examination and radiographic recordings. Table 1 presents the results of the clinical evaluation. Apart from the caries prevalence, no significant differences were observed between the two groups, although the caries-active group revealed a tendency to lower salivary flow rate, higher bacteria levels, higher plaque index, and papillary bleeding index. Evaluation of the questionnaire revealed no significant differences in regard to frequency, duration, or technique of self-performed oral hygiene, dental visits, or intake of milk products, sweets, sucrose-containing drinks, or fluoride supplements. One week prior to the study, all individuals were put on the identical diet deficient in milk products. None of the subjects received any medication. Plasma samples were taken at 7:30 AM on 3 consecutive days. Urine was collected from 7:00 AM on the first day until 7:00 AM on the third day: 7: 00 AM-J : 00 PM, ] : 00 PM--6 : 00 PM, 6 : 00 PM--] J : 00 PM, and 11 : 00 PM-7 : 00 AM. At 7 : 30 AM on the second day each individual received 0.5 g calcium (kindly supplied by Sandoz). Urine and/or plasma samples were analyzed for creatinine (Jaffb
Caries active
Caries inactive
Salivary flow rate (ml/min) Unstimulated Stimulated Buffer capacity score a
0.19 __+0.07 0.93 __0.32 2.75 -t- 0.25
0.52 _+0.16 1.63 + 0.45 3.00 +_0.00
S. mutans score b
Lactobacilli score ~
3.00+_0.00 2.75 + 0.95
1.67+0.67 2.00 _+0.58
Plaque index Papilla bleeding index
2.42 _+0.31 1.86 _+0.04
1.86 + 0.11 1.46_+ 0.13
37.50 __ 5.55 * 40.25 _+6.45 *
4.00_+ 1.58 8.00_+ 1.96
DMF-S a DeMF-S *
a The salivary buffering capacity was determined as recommended by the manufacturer and scored as follows: 1 = l o w (final pH _ 6.0) b The growth density of S. mutans was categorized as recommended by the manufacturer: 0 = n o growth, 1 = l o w ( 105 C F U / m l but < 106 CFU/ml), 3 = h i g h ( > 106 CFU/ml) The growth density of lactobacilli was classified as recommended by the manufacturer and scored as follows: 1 = _
Clin Investig (1992) 70:735-739
Original ANele
© Springer-Verlag 1992
Caries susceptibility and renal excretion of calcium I. Mosch~n 1, W. Schobersberger 2, L. Klotz 2, E. Jarosch 1, M. Richter 1, and F. Lang 2 1 Universit/itsklinik fiir Zahn-, Mund- und Kieferheilkunde, Universitfit Innsbruck 2 Institut ftir Physiologic der Universit/it Innsbruck
Summary. Clearance studies were performed for 2 days in two groups of age-matched young female volunteers: those with low caries prevalence and those with high caries prevalence. Both groups were kept on a low-calcium diet for 1 week and received 0.5 g calcium at the beginning of the second day. In both groups, glomerular filtration rate, urinary flow rate and renal excretions of sodium, calcium, and phosphate were subject to significant circadian variations. In both groups the administration of calcium led to a significant increase in renal excretion of sodium and calcium and a significant decrease in that of phosphate. On the first day, calcium excretion was significantly greater in those with low caries prevalence than in those with high caries prevalence, pointing to altered calcium homeostasis in this group. Key words: Kidney - Calcium - Phosphate - Sodium - Caries
The crucial event in the development of carious lesions is the demineralization and dissolution of enamel by local acidity as the result of organic acid production by oral bacteria during metabolism of carbohydrates [1]. The local remineralization of the enamel surface, on the other hand, depends in part on the ambient concentrations of calcium and phosphate [16], which may be sensitive to the mineral balance of the individual. Calcium and phosphate balance depends on the interplay of intestinal absorption and renal excretion [5, 11]. Up to now, however, the evidence for a contribution of altered mineral metabolism to the pathophysiology of caries remained equivocal [14]. The present study was performed to test for altered renal calcium and/or phosphate excretion in individuals with a low level of past caries experience. To this end, clearance studies were performed in young women (student nurses) with either low or high caries prevalence subjected to a low-calcium diet.
Methods The 15 individuals volunteering for this study were female student nurses (aged 17-19 years). Seven had low caries prevalence (caries-inactive group), and eight had high caries prevalance (caries-active group). None of the participants reported the use of chlorhexidine digluconate preparations or had a recent history of antibiotics or systemic diseases. An interview was conducted immediately before the clinical examination using a structured questionnaire comprising 110 questions; the interview lasted about 50 min. The questionnaire included questions regarding general health and medication, tobacco use, dietary habits and between-meal habits during an "ordinary week," consumption of sweets, oral hygiene habits, use of fluorides, and dental visits. All intraoral examinations were performed by a single dental examiner. The clinical examination was carried out under optimal clinical conditions and included the parameters described below.
Salivary factors Secretion rate of both unstimulated and paraffinwax stimulated whole saliva was measured as described by Heintze et al. [9]. Buffering capacity of saliva was measured according to Ericson and Bratthall [7] (Dentobuff strip; Orion Diagnostica, Espoo, Finland).
Bacteriologic procedures The levels of salivary Streptococcus mutans and Lactobacillus were determined by the dip-slide technique, using commercial Dentocult SM and LB slides (Orion Diagnostica, Espoo, Finland). [3, 10]. The growth intensity was categorized as recommended by the manufacturer.
736
Oral hygiene
Table 1. Results of clinical examination
The amount of plaque was scored by the Turesky modification of the Quigley-Hein index [18]. A score of 0-5 was assigned to each facial and lingual surface of all available teeth. Before scoring, the plaque was removed with an erythrosine dye solution.
Variable
Gingival inflammation The degree of gingival inflammation was measured by the papilla bleeding index [15], in which gingivitis is scored on a 0-4 scale according to the bleeding from the gingival sulcus after gentle probing.
Caries prevalence All individuals were submitted to professional tooth cleaning prior to caries examination. The criteria according to M611er and Poulson [13] were used. In the front area approximal lesions were assessed with the aid of a fiber light. Four posterior bitewing radiographs were taken of each subject using the long-cone right-angle technique and the Rinn device for correct exposure geometry. Radiographic recordings were carried out blindly according to Gr6ndahl et al. [8]. The D M F - T / D M F - S index was determined by the combination of clinical examination and radiographic recordings. Table 1 presents the results of the clinical evaluation. Apart from the caries prevalence, no significant differences were observed between the two groups, although the caries-active group revealed a tendency to lower salivary flow rate, higher bacteria levels, higher plaque index, and papillary bleeding index. Evaluation of the questionnaire revealed no significant differences in regard to frequency, duration, or technique of self-performed oral hygiene, dental visits, or intake of milk products, sweets, sucrose-containing drinks, or fluoride supplements. One week prior to the study, all individuals were put on the identical diet deficient in milk products. None of the subjects received any medication. Plasma samples were taken at 7:30 AM on 3 consecutive days. Urine was collected from 7:00 AM on the first day until 7:00 AM on the third day: 7: 00 AM-J : 00 PM, ] : 00 PM--6 : 00 PM, 6 : 00 PM--] J : 00 PM, and 11 : 00 PM-7 : 00 AM. At 7 : 30 AM on the second day each individual received 0.5 g calcium (kindly supplied by Sandoz). Urine and/or plasma samples were analyzed for creatinine (Jaffb
Caries active
Caries inactive
Salivary flow rate (ml/min) Unstimulated Stimulated Buffer capacity score a
0.19 __+0.07 0.93 __0.32 2.75 -t- 0.25
0.52 _+0.16 1.63 + 0.45 3.00 +_0.00
S. mutans score b
Lactobacilli score ~
3.00+_0.00 2.75 + 0.95
1.67+0.67 2.00 _+0.58
Plaque index Papilla bleeding index
2.42 _+0.31 1.86 _+0.04
1.86 + 0.11 1.46_+ 0.13
37.50 __ 5.55 * 40.25 _+6.45 *
4.00_+ 1.58 8.00_+ 1.96
DMF-S a DeMF-S *
a The salivary buffering capacity was determined as recommended by the manufacturer and scored as follows: 1 = l o w (final pH _ 6.0) b The growth density of S. mutans was categorized as recommended by the manufacturer: 0 = n o growth, 1 = l o w ( 105 C F U / m l but < 106 CFU/ml), 3 = h i g h ( > 106 CFU/ml) The growth density of lactobacilli was classified as recommended by the manufacturer and scored as follows: 1 = _
