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Biomedical subjects

M Knuuttila

Publications and source records attributed to M Knuuttila.

At least 19 recordsLinked to original sources
PubMed2000

Alveolar bone loss in type 1 diabetic subjects.

UNLABELLED: AIM, BACKGROUND: The aim of this study was to assess the degree of marginal alveolar bone loss in a group of young subjects with type 1 diabetes mellitus (DM) (n=35, age range 24-36 years) and age-matched non-diabetic control subjects (n=10). METHOD: The diabetic group was divided into 3 subgroups (D1, D2, D3) according to the severity of the diabetic state. The level of alveolar bone was measured on panoramic radiographs of maxillary and mandibular molars as the % of the distance between the cemento-enamel junction (CEJ) and the bone crest along the total length of the root. All mesial and distal sites with a distance of > 15% (BL>15%) were picked, and calculations were performed using the individual %s of sites with BL> 15%. RESULTS: Based on the present findings, we conclude that type 1 DM has a modifying effect on marginal loss of alveolar bone. A clear trend towards increased marginal bone loss was seen in the subjects with complicated DM (D3). The subjects with good metabolic control and no complications of DM (D1) are no more susceptible to marginal bone loss than non-diabetic controls of the same age. CONCLUSIONS: The present findings confirm our previous results on increased loss of periodontal support in subjects with complicated DM already at an early age.

Adult↗
PubMed1999

Improved bone biomechanical properties in rats after oral xylitol administration.

The effects of 5, 10, and 20% dietary xylitol supplementations on the biomechanical properties, histological architecture, and the contents of collagen, pyridinoline, and deoxypyridinoline in long bones of rats were studied. Tibiae were used for the three-point bending test, and femurs were used for the torsion and loading test of the femoral neck. The 10 and 20% oral xylitol administrations caused a significant increase of tibial stress, femoral shear stress, and stress of the femoral neck as compared with the controls. Parallel, but not significant, effects were also seen in the 5% xylitol supplementation group. No significant differences in strain or Young's modulus of the tibiae were detected between the groups. An increased shear modulus of elasticity in femurs was detected in the 20% supplementation group as compared with the controls. The histomorphometrical data for the secondary spongiosa of the proximal tibia revealed that trabecular bone volume was significantly greater in all dietary xylitol supplementation groups as compared with the controls. The bone volume increased along with increasing xylitol content. No significant differences between the groups were detected concerning the amount of collagen per dry weight of organic matrix, the concentrations of pyridinoline or deoxypyridinoline in collagen, or the ratio of these crosslinks. This suggests no xylitol-dependent selective changes in these structures of bone collagen. In conclusion, dietary xylitol supplementation in rats improves the biomechanical properties of bone and increases the trabecular bone volume dose dependently.

Administration, Oral↗
PubMed1997

Dietary xylitol retards the ovariectomy-induced increase of bone turnover in rats.

The effects of 10% dietary xylitol supplementation in ovariectomized rats were studied on the degradation of bone organic and inorganic structures. The osseal concentrations of hydroxyproline, pyridinoline, and deoxypyridinoline were analyzed by high-performance liquid chromatography. Bone resorption was measured in [3H]tetracycline-prelabeled rats by urinary excretion of 3H, and by the amount of 3H preserved in bone. Bone trabeculation was measured by a computer image analyzer from sections stained by the method of von Kossa. The amount of collagen in bone organic fraction was lower in ovariectomized rats as compared with the sham-operated controls. This most likely is partly a consequence of an increased resorption, and partly a consequence of a higher proportion of immature periosteal bone in the ovariectomized animals, leading to a higher ratio of noncollagenous protein to collagen. The number of pyridinium crosslinks was lower in proportion, indicating no selective changes in the structure of collagen. Dietary xylitol significantly retarded the ovariectomy-associated decrease in the relative amount of collagen and the number of its mature crosslinks. Ovariectomy doubled the excretion of 3H and caused a significant decrease in the amount of 3H preserved in bone; both these changes were significantly retarded by the 10% dietary xylitol supplementation. Ovariectomy significantly decreased the volume of bone trabeculae, but this effect was also significantly inhibited by the xylitol supplementation in the diet. In conclusion, these findings suggest a dietary xylitol-induced normalizing effect on the rate of bone turnover in ovariectomized rats.

Animals↗
PubMed1995

Diminished bone resorption in rats after oral xylitol administration: a dose-response study.

The effects of 5, 10, and 20% dietary xylitol supplementations on the resorption of bone were studied. The resorption was measured by the urinary excretion of [3H] radioactivity from [3H]tetracycline-prelabeled rats. The 10 and 20% oral xylitol administrations caused a significant decrease in the excretion of [3H] as compared with the control group with no xylitol supplementation. The effect was detected as early as 2 days after the beginning of xylitol-feeding and was maintained throughout the experimental period of 31 days. The retarding effect on bone resorption was about 25% in the 10% xylitol group, about 40% in the 20% xylitol group, and undetectable in the 5% xylitol group. The amount of preserved [3H] radioactivity in the tibiae of the 10 and 20% xylitol groups after the experiment clearly exceeded the values of the control group. The mechanism of the retarded bone resorption caused by dietary xylitol still remains obscure, but an increased absorption of calcium may be involved. In conclusion, dietary xylitol supplementation in rats seems to retard the bone resorption in a dose-dependent way. The effect is achieved rapidly and is maintained at least over a period of 1 month xylitol feeding.

Administration, Oral↗
PubMed1995

Adult diabetic and nondiabetic subjects as users of dental services. A longitudinal study.

Utilization of dental services by 30 diabetic and 30 nondiabetic subjects was assessed by longitudinal monitoring over a period of 3 years. All subjects were examined clinically three times, and their treatment consisted mainly of cariologic and periodontal treatment. The treatment was delivered by a dentist and an expanded-duty dental hygienist. The study groups were similar with regard to the total number of dental visits needed. However, the treatment of diabetic subjects was more demanding in that more dentist's workload was needed for the diabetic group. They also missed more appointments without cancellation and therefore more office time had to be reserved for them.

Adult↗
PubMed1994

Dietary xylitol prevents ovariectomy induced changes of bone inorganic fraction in rats.

Thirty-six 3-month-old female Wistar rats were labelled with a single intraperitoneal tetracycline injection. Twenty-four animals were subsequently ovariectomized, while the control group of 12 animals underwent sham operations. All animals received the basal Ewos R3 diet and half of the ovariectomized animals (n = 12) were given an additional 5% dietary xylitol supplementation. Three months later, following the collection of blood and urine, the animals were killed by decapitation. The tibiae were detached and prepared for chemical and other studies. The weight and density of the tibiae were measured. The right tibiae were dried and pulverized for chemical analysis of calcium, phosphorus and citric acid. The total inorganic fraction was determined by ashing the powdered bone. The left tibiae were cross-sectioned at the tibio-fibular junctions for the measurement of the width of periosteally formed bone, which was identified by tetracycline fluorescence. The examination of mineral content of bone was performed by scanning electron microscopy, using an electron probe microanalytic technique. The results indicate that the supplementation of the diet with 5% xylitol had a protective effect against the loss of bone mineral after ovariectomy in the rat. This was clearly seen in tibial density and in the inorganic fraction of the bone, and in the concentrations of bone Ca and phosphorus. Ovariectomy caused a doubling in periosteal bone formation relative to the controls, whereas the growth of the periosteally formed bone was somewhat reduced following xylitol supplementation as compared with ovariectomy alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

The effect of dietary xylitol on dentin formation in ovariectomized rats.

Twenty-nine 3-month-old female Wistar rats were labeled by means of a single intraperitoneal tetracycline injection. Nineteen animals were subsequently ovariectomized, whereas a control group of 10 animals underwent sham operations. All the animals received the basal diet, and 10 of the ovariectomized animals were given an additional dietary xylitol supplementation (5%). Three months later the animals were killed by decapitation, and dentinal apposition on the molars was measured. The results indicate that supplementation of the diet with 5% xylitol had an attenuating effect on the enhanced dentin formation caused by ovariectomy, but the mechanism remains unsolved.

Animals↗
PubMed1994

Clinical and radiologic assessment of possibilities for endosseous implants and osseointegrated prostheses in 55-year-old edentulous subjects.

To determine how many 55-year-old edentulous subjects were suitable candidates for implant-retained overdentures of fixed implant bridges and how many of them might be interested in such treatment, case histories were reviewed, and clinical and radiologic examinations were performed on 146 subjects (100 women, 46 men) in a medium-sized city in northern Finland. Numbers and lengths of implants required in altogether 16 regions in the upper and lower jaw were evaluated. The commonest implant length was 8 mm in the upper jaw and 16 mm in the lower jaw. Construction of an implant-retained fixed bridge would have been possible in the upper jaw in 121 subjects (83%) and of an overdenture in all lower jaws. Information about the benefits of the treatment is important because, although the percentage of subjects who were suitable candidates for implant-retained prostheses was high, few subjects were aware of or interested in this type of treatment.

Alveolar Bone Loss↗
PubMed1994

Dietary xylitol retards bone resorption in rats.

Dietary xylitol has previously been found to promote the content of calcium and minerals of the bone during rehabilitation following dietary calcium deficiency and during a normocalcemic diet in rats. This in vivo experiment was performed in order to study whether a short-term dietary xylitol supplementation affects bone resorption and calcium incorporation into bone during two different experiments utilizing either calcium-deficient or normocalcemic diets. Xylitol reduced bone resorption measured by the urinary excretion of 3H radioactivity both during calcium-deficient and normocalcemic diets. However xylitol reduced vitamin D levels only during calcium deficiency, indicating that the decreased bone dissolution was not associated with changes in 1,25(OH)2D3 concentration alone. Dietary xylitol did not alter 45Ca incorporation into bone, although this does not exclude the possibility that xylitol may have caused alterations in bone apposition. These results suggest that a short-term xylitol ingestion retards bone resorption in the rat.

Animals↗
PubMed1993

The effect of dietary xylitol on recalcifying and newly formed cortical long bone in rats.

Thirty-six 3-week-old male Wistar rats were labeled with a single intraperitoneal tetracycline injection. Twenty-four of them were then fed a Ca-deficient basal diet for 3 weeks, while the control group received the basal diet supplemented with CaCO3 (12 g/kg). The tetracycline labeling was then repeated and six animals in each group were decapitated. The diet of the remaining formerly Ca-deficient animals was returned to normal, and half the test rats also received xylitol supplementation (50 g/kg). After 4 weeks of rehabilitation the labeling was repeated and the animals were decapitated and their tibias were prepared. The tibias were measured in terms of weight and density and cross sections were prepared for the examination of mineral content. Bone element analysis was performed by scanning electron microscopy with electron-probe microanalysis, examining separately the bone areas formed during the various dietary periods. Areas of the former Ca-deficient and newly formed cortical bone were identified by tetracycline fluorescence under ultraviolet light, and the amount of cortical bone in each group was measured. The mineralization-promoting effect of dietary xylitol as compared with CaCO3 supplementation alone was seen more clearly in the newly formed periosteal bone than in remineralization of the formerly Ca-deficient bone, the concentrations of Ca and P being significantly elevated (P < 0.05), as also was the total mineral content (P < 0.01). The cortical bone volume was similar following the CaCO3 and CaCO3 + xylitol supplementations, suggesting unaltered formation of the organic matrix. The results show that the effect of xylitol on bone during dietary Ca rehabilitation particularly concerns newly formed bone mineral.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Citric acid concentration compared to serum parathyroid hormone, 1,25(OH)2D3 and calcitonin during dietary Ca deficiency and rehabilitation enhanced with xylitol in rats.

Young male Wistar rats were fed on a Ca-deficient diet for 3 weeks, after which dietary Ca was restored with either CaCO3 or CaCO3 + xylitol (5% per weight). Citric acid, Ca, Mg, Zn and P were determined in the tibia and femur at the beginning and after 2 and 4 weeks of rehabilitation, and serum and urinary citric acid and serum 1,25(OH)2D3, parathyroid hormone (PTH) and calcitonin were measured at the same points in time. The diminished bone Ca (p < 0.001) after 3 weeks of deficiency did not reduce the bone citric acid concentration, although serum citrate increased markedly. Simultaneously the serum 1,25(OH)2D3 concentration more than doubled and PTH increased (p < 0.01). Rehabilitation with CaCO3 + xylitol reduced the 1,25(OH)2D3 concentration to below the control level (p < 0.05), while serum citric acid remained elevated. CaCO3 alone normalized the elevated hormone and citric acid levels in the serum. Dietary CaCO3 and CaCO3 + xylitol normalized the PTH concentration equally well. The gain in bone Ca after 4 weeks of rehabilitation was significantly greater when xylitol was added compared with CaCO3 alone (p < 0.05). Only the 4-week CaCO3 + xylitol group attained the bone Ca concentration of the controls. Xylitol supplementation seems to affect the serum citric acid concentration independent of 1,25(OH)2D3 and PTH concentrations. The elevated citric acid concentration could be associated with increasing bone Ca.

Animals↗
PubMed1991

Immediate response to nonsurgical periodontal treatment in subjects with diabetes mellitus.

The short-term response (3-4 months) to non-surgical periodontal treatment, i.e., oral hygiene instruction, scaling and root planing, was determined in 34 diabetic and 45 control subjects. Measurements of probing pocket depth and gingival bleeding (%) were used for evaluation. No significant difference could be observed in the response to non-surgical periodontal treatment between the diabetics and controls.

Adolescent↗
PubMed1991

Risk factors associated with abundant dental caries and periodontal pocketing.

An adult population of 1275 subjects aged 25, 35, 50, and 65 yr were examined clinically with respect to their periodontal and caries situation. An interview and questionnaire were used to chart the following variables: dietary and oral hygiene habits, social factors, appreciation of natural teeth, and use and availability of dental services. The associations between the risk factors and the probability of periodontal pocketing (greater than or equal to 4 mm) or abundant dental caries (greater than or equal to 7 lesions) among the dentate population were examined using a logistic regression model. The final model correctly classified periodontal pocketing in 65% of the cases and abundant caries in 76%. In addition to social variables, behavioral factors were found to be significantly associated with periodontal pocketing and abundant untreated dental caries.

Adult↗
PubMed1991

Increment of caries in diabetic adults. A two-year longitudinal study.

The increment of caries was monitored for two years in 30 adult diabetic and 30 healthy subjects, who received regular preventive and reparative treatment during this time. No significant differences in caries increment were found between the diabetic and control subjects, but there was a tendency for a greater increment on lingual surfaces of the teeth in the diabetic group than in the healthy subjects (P less than 0.09).

Adult↗