Active clinical trials for "Calcium Metabolism Disorders"

The experimental study investigates which metabolic responses of calcium and parathyroid hormone are observable in blood and urine in a cohort of 41 healthy adults following a sequence of different exposures: low-calcium water first and high-calcium water afterward.

Evaluation of the effect of hyaluronic acid with hydroxyapatite versus hydroxyapatite alone on bone regeneration following enucleation of mandibular odontogenic cyst.

Twenty patients scheduled for lateral-window sinus floor Elevation (SFE) are randomized into two groups: use of SYMBIOS® Biphasic Bone Graft Material (Group 1) or of Algipore® Bone Substitution Material (Group 2). Biopsies are taken 3 months after SFE and during implant surgery after 6 months. One ground section per biopsy (n=40) is stained, scanned, and histomorphometrically analyzed for new bone, old bone, soft tissue, graft, bone infiltration of graft, bone-to-graft contact, and penetration depth.

The investigators aim to recruit 60 women who have agreed to participate in an existing randomized, double-blind, placebo-controlled trial (Treatment of Vitamin D Insufficiency, HSC 2009-0055). In this trial, the investigators propose to evaluate the associations between magnesium intake, magnesium stores, fractional magnesium absorption and calcium homeostasis. The investigators will stratify 60 subjects in the sub-study, ensuring that approximately 20 subjects are randomized into each treatment arm (placebo, low-dose and high-dose vitamin D). The investigators already assess calcium homeostasis throughout the study by measuring bone mineral density, fractional calcium absorption, serum and urine calcium levels, among other tests. In the sub-study of 60 women, the investigators will evaluate whether habitually higher magnesium intake increases or decreases fractional calcium absorption. The investigators will evaluate the interplay between magnesium stores, vitamin D levels and serum parathyroid hormone levels. The investigators will directly assess magnesium stores using serum magnesium and 24-hour urine magnesium levels, and will measure magnesium absorption using the dual stable isotope approach.

This will be a double-blind, randomized, three-arm parallel groups study of the effect of toothpastes containing Ca-hydroxyapatite (HAP), Mg-Zn-hydroxyapatite (Zn-Mg-HAP), or fluoroapatite (FAP). The aim of the study is to compare the effect of toothpastes containing Ca-hydroxyapatite (HAP), fluoroapatite (FAP), and Mg-Zn-hydroxyapatite (Mg-Zn-HAP) on dentin hypersensitivity associated with dental abrasion. Materials and methods. Thirty consent patients aged 35-45 with dentin hypersensitivity associated with abrasion will be recruited for the study. The study will have 2 phases: preparatory phase (recruitment of the patients, standardization of their oral hygiene protocols, wash-out period, calibration of the researchers and training) and the main part (double-blind, randomized, parallel groups study of toothpastes effect). Patients will be randomly divided into 3 groups (group 1 - toothpastes with Ca-HAP, group 2 - toothpastes with Zn-Mg-HAP, group 3 - toothpastes with FAP). Clinical examination will be performed at the baseline, after 2 and 4 weeks, and will include patient's interview, oral hygiene level assessment (OHI-S), and dentin sensitivity testing (Shiff's index). The null hypothesis is that there will be no statistically significant differences in dentin sensitivity level between the study groups.

This multicenter, non-inferiority trial randomized, double-blind, active controlled parallel group study evaluates the hypothesis that the home regular use of a toothpaste containing microcrystalline hydroxylapatite (HAP) (test toothpaste) provides a caries preventive effect in caries-active children with primary dentition age 3-6 which is comparable to the caries preventive effect provided by the regular use of a fluoridated tooth paste (F) (control toothpaste) over observation periods of max. 336 days. Caries development will be assessed according to the clinical criteria of the International Caries Detection and Assessment System (ICDAS). Condition or disease: Intervention Procedure: Tooth Brushing HAP or Procedure: Tooth Brushing F

Target question is as the following one: Does the daily use of a fluoride-free, microcrystalline hydroxyap-atite (HAP) - containing test toothpaste have a non-inferior caries preventing effect in the permanent dentition compared to the regular use of a fluoride control toothpaste (1450 ppm F-) with proven caries preventive efficacy (Walsh et al. 2019)? This multicenter, non-inferiority clinical trial, randomized, double-blind, active-controlled design, two-armed study evaluates the hypothesis that the home regular use of a toothpaste containing microcrystalline hydroxylapatite (HAP) (test toothpaste) provides a caries preventive effect in adults aged 18-45 comparable to the caries preventive effect provided by the regular use of a fluoridated tooth paste (1450 ppm -F) (control toothpaste) over observation periods of max. 18 months. Caries development will be assessed according to the clinical criteria of the Decay Missing Filling Surface Index (DMFS).

This prospective, single-blind, matched controlled study aims to evaluate the effect of proton pump inhibitors on biochemical markers of calcium and bone metabolism in an effort to establish additional biological plausibility for the apparent association between proton pump inhibitors (PPIs) and osteoporosis-related fractures. Young males (age 18-45 years), who are either healthy volunteers, or who complain of daily or frequent heartburn but are otherwise healthy, will be recruited and enrolled in the study. Patients with heartburn will be assigned to the intervention group and will be assigned to take a PPI for three months. Healthy volunteers will be matched by age to patients in the intervention group and will act as the control group. 70 patients will be enrolled in total. Blood studies for all subjects will be taken at 0, 1 and 3 months to test for various biochemical markers of calcium and bone metabolism, which act as surrogate markers of calcium absorption and bone remodeling. Levels of biochemical markers in the two groups will be compared using two-way analysis of variance (ANOVA). Changes in biochemical parameters within a group will be assessed using repeated measures ANOVA.

Use of proton pump inhibitors (PPI) has increased in recent years. There are concerns that PPIs have possible negative effects on bone metabolism. It has been suggested that PPIs may reduce the absorption of calcium from the small intestine and lead to bone resorption by affecting osteoclastic activity. In this study, it is planned to investigate the effects of lansoprazole, a proton pump inhibitor, on bone turnover markers in pediatric patients with gastroesophageal reflux or gastroesophageal reflux disease.

In this pre-post observational study, the investigators will enroll and follow a cohort of about 50 adults undergoing sleeve gastrectomy surgery for weight loss. Pre-operatively and at 6 and 12 months post-operatively, the investigators will use state-of-the-art metabolic and imaging techniques to evaluate calcium metabolism and skeletal health. Specific outcomes include intestinal calcium absorption capacity, bone mineral density (BMD) assessed by dual-energy X-ray absorptiometry (DXA) and quantitative computed tomography (QCT), and bone structure assessed by QCT and high-resolution peripheral QCT (HR-pQCT).