Immunolocalization of AQP5 in resting and stimulated normal labial glands and in Sjögren's syndrome.

OBJECTIVE: In our current work, in vivo examination of AQP5 distribution in labial salivary glands following stimulation of secretion has been carried out in normal individuals and in patients with Sjögren's syndrome. SUBJECTS AND METHODS: For this study, we selected five patients with primary Sjögren's syndrome (mean age 62.4 ± 10.6 s.d. years) diagnosed in accordance with the European Cooperative Community classification criteria. There were five patients (mean age 27 ± 2.5 s.d. years) in the control group. The subcellular distribution of AQP5 in human labial gland biopsies was determined with light and immunoelectron microscopy before and 30 min after administration of oral pilocarpine. RESULTS: In unstimulated control and Sjögren's labial glands, AQP5 is about 90% localized in the apical plasma membrane, with only rarely associated gold particles with intracellular membrane structures. We have found no evidence of pilocarpine-induced changes in localization of AQP5 in either healthy individuals or patients with Sjögren's syndrome. CONCLUSIONS: Our studies indicate that neither Sjögren's syndrome itself, nor muscarinic cholinergic stimulation in vivo caused any significant changes in the distribution of AQP5 in the labial salivary gland cells.

Influence of individual brightness and contrast adjustment on accuracy of radiographic measurements of infrabony defects.

OBJECTIVES: To assess the accuracy of radiographic measurements of infrabony defects and to compare the accuracy with and without individual digital adjustment of brightness and contrast. METHODS: In 41 periodontitis patients (19 females, 22 males; age range 23-73 years), 50 radiographs of 50 infrabony defects were obtained. All radiographs were digitized. Using a personal computer program, the linear distances between cemento-enamel junction (CEJ) and alveolar crest (AC) and between CEJ and bony defect (BD), and the depth of the infrabony defect (INFRA), were measured twice, according to the individual judgement of the radiographic examiner: (1) without digital adjustment (W) and (2) after use of contrast and brightness adjustment (A). Intrasurgical bone measurements served as the gold standard. The accuracy of measurements with or without digital adjustment was compared. RESULTS: Radiographic measurements underestimated the gold standard for CEJ-BD (W: 1.1 mm ± 1.8 mm, P < 0.001; A: 1.0 mm ± 1.9 mm, P = 0.001). Both CEJ-AC (W: 0.2 mm ± 2.5 mm; A: 0.5 mm ± 2.6 mm) and INFRA (W: -0.4 mm ± 2.4 mm; A: -0.6 mm ± 2.5 mm) measurements came close to the gold standard. Statistically significant differences between W and A regarding accuracy were not observed. CONCLUSIONS: The measurement tool used in this study provided high-accuracy measurements of periodontal bone loss in INFRA. Individual brightness and contrast adjustment failed to improve accuracy.

Differentiation potential of stem cells from human dental origin - promise for tissue engineering.

Recent studies have revealed the existence of stem cells in various human tissues including dental structures. We aimed to establish primary cell cultures from human dental pulp and periodontal ligament, to identify multipotential adult stem cells in these cultures, and to study the differentiation capacity of these cells to osteogenic and to neuronal fates. Dental pulp and the periodontal ligament were isolated from extracted human wisdom teeth. The extracellular matrix was enzymatically degraded to obtain isolated cells for culturing. Both dental pulp and periodontal ligament derived cultures showed high proliferative capacity and contained a cell population expressing the STRO-1 mesenchymal stem cell marker. Osteogenic induction by pharmacological stimulation resulted in mineralized differentiation as shown by Alizarin red staining in both cultures. When already described standard neurodifferentiation protocols were used, cultures exhibited only transient neurodifferentiation followed by either redifferentiation into a fibroblast-like phenotype or massive cell death. Our new three-step neurodifferentiation protocol consisting of (1) epigenetic reprogramming, then (2) simultaneous PKC/PKA activation, followed by (3) incubation in a neurotrophic medium resulted in robust neurodifferentiation in both pulp and periodontal ligament cultures shown by cell morphology, immunocytochemistry and real time PCR for vimentin and neuron-specific enolase. In conclusion, we report the isolation, culture and characterization of stem cell containing cultures from both human dental pulp and periodontal ligament. Furthermore, our data clearly show that both cultures differentiate into mineralized cells or to a neuronal fate in response to appropriate pharmacological stimuli. Therefore, these cells have high potential to serve as resources for tissue engineering not only for dental or bone reconstruction, but also for neuroregenerative treatments.

[The topographoanatomical features of "parapancreal" fatty spaces and ways of spread of the pathological process in acute destructive pancreatitis].

Three corpses of humans and 24 organocomplexes were used to study specific features of the structure of peritoneal-fascial space of the retroperitoneal area. The determined specific features helped to establish certain regularities of spread of the pathological process in 92 patients with acute destructive pancreatitis.

Healing of human intrabony defects following regenerative periodontal therapy with a bovine-derived xenograft and guided tissue regeneration.

The purpose of the present study was to histologically evaluate the healing of human intrabony defects following treatment with either a bovine-derived xenograft (BDX) and guided tissue regeneration (GTR) [BDX + GTR] or a bovine-derived xenograft mixed with collagen (BDX Coll) and GTR [BDX Coll + GTR]. Eight patients with chronic periodontitis and each with one very deep intrabony defect around a tooth scheduled for extraction were treated with either a combination of BDX + GTR (five patients) or with BDX Coll + GTR (three patients). The postoperative healing was uneventful in all eight cases. After a healing period of 6 months, the teeth or roots were extracted together with some of their surrounding soft and hard tissues and subsequently fixed in 10% buffered formalin. Following decalcification in EDTA, the specimens were embedded in paraffin and 8-microm histological sections were cut in the mesio-distal direction, parallel to the long axes of the teeth. The sections were alternatively stained with hematoxylin and eosin, van Giesson's connective tissue stain or with the Ladevig's connective tissue staining method and examined under the light microscope. Generally, formation of new cementum with inserting collagen fibers was found in seven out of the eight treated cases, whereas in the remaining case (treated with BDX + GTR) the healing was characterized by formation of a long junctional epithelium along the debrided root surface and no formation of cementum or bone. In the specimens demonstrating periodontal regeneration the new cementum was always of a cellular type. In most cases, the graft particles were surrounded by bone. In some areas, the bone tissue around the graft particles was connected by perpendicularly inserting collagen fibers to the newly formed cementum on the root surface. The epithelium downgrowth stopped always at the most coronal part of the newly formed cementum. No remnants of the membrane material were observed in any of the biopsies. Connective tissue encapsulation of the graft particles was rarely observed and was limited to the most coronal part of the defects. The findings of the present study provide evidence that treatment of intrabony defects with both BDX + GTR and BDX Coll + GTR may enhance periodontal regeneration in humans.

[Bacteriologic investigation of periodontal infections]. / Mikrobiológiai vizsgálatok parodontális eredetú gyulladásos kórképekben.

The gingivitis and periodontitis are very common diseases in Hungary: more than 80% of the adult population suffers with gingivitis and 15-20% has destructive periodontitis. The composition of peridontopathogenic bacterial flora is totally different from that of the bacterial flora causing dental infections. In periodontal infections dominantly facultative and obligatory anaerobic microorganisms occur (Actinobacillus actinomycetemcomitans (A. actinomycetemcomitans), Porphyromonas gingivalis (P. gingivalis), Bacteroides forsythus (B. forsythus). The main objective of the study was to investigate the microbial flora of the rapidly progressing periodontitis with special respect to the occurrence of the Actinobacillus actinomycetemcomitans. The antibiotic susceptibility of the A. actinomycetemcomitans was also determined against the most frequently used conventional antibiotics. Twenty-five samples collected from patients with rapidly progressing periodontitis were examined. Prevalence and ratio of A. actinomycetemcomitans and other species of the periodontal anaerobic flora were investigated. MIC values of different antibiotics used routinely--clindamycin, amoxicillin/clavulanic acid, tetracycline, metronidazole--were measured. Prevalence of black pigmented bacteroides (50%), and A. actinomycetemcomitans (30%) was comparable to data of foreign investigators. A. actinomycetemcomitans spp. appear to be more sensitive to clindamycin and amoxicillin/clavulanic acid and more resistant to metronidazole compared to published data. The knowledge of microbial composition of the periodontal flora could help to diagnose the different forms of periodontitis. It can also assist the indication of the most appropriate antibiotic therapy.

[Effect of the quality of restorations and of dental prosthesis on the alveolar bone loss in patients with chronic destructive periodontitis]. / A konzerváló és protetikai munkák minóségének hatása krónikus destruktív parodontitisben szenvedó betegek alveoláris csontnívójára.

In recent years many risk factors have been implicated in the etiology of destructive periodontitis. The quality of the previous dental works might play a decisive role in the development of periodontal attachment loss. The main objective of the present clinical study was to evaluate the aggravating role of the subgingival restorations with questionable quality and the interproximal untreated carious lesions in the progression of periodontal attachment loss in a randomly selected group of patients with destructive periodontitis. The panoramic radiographs of 170 randomly selected patients suffering with destructive periodontitis were analyzed and the quality of the approxima restorations, the presence or absence of interproximal untreated carious lesions and the interdental bone loss were recorded. The level of interproximal bone around the teeth with restorations or with approxima carious lesions were compared with the sound contralateral counterparts and with the overall average alveolar bone level. Some more than 50% of 2175 approxima restorations were faulty. 280 untreated carious lesions were present in 170 subjects. The interproximal bone loss was always greater around teeth with untreated carious lesions or with faulty restoration. The differences between the control teeth and the carious teeth were statistically significant (P < 0.01) excepting the maxillary front and mandibular premolar region. The differences between the teeth with faulty restorations and the controls were statistically significant (P < 0.01) in the mandible and in the maxillary molar region. Although there were significant differences between teeth with untreated carious lesions or with faulty restoration and the controls in many regions of the dental arch, the differences clinically were not always necessarily significant, showing only less than 0.5 mm differences in bone levels, In conclusion the faulty restorations and untreated carious lesions do not seem to be decisive aggravating risk factors leading to bone loss in patients with chronic destructive periodontitis.

Periodontal treatment needs in Central and Eastern Europe.

The aim of the present review is to evaluate the periodontal conditions and treatment needs in Central and Eastern Europe and to compare these data to the epidemiological data from the industrialised and developing countries. The recent prevalence and severity data provided by national surveys based on the CPITN methods are summarised. The periodontal conditions in the age groups 15-19 and 35-44 are discussed in detail. The CPITN data show no major differences in the extent and severity of destructive periodontal disease in different countries. In the age group 15-19 just a few European surveys reported 'score 4 sextant' and the prevalence of 'score 3' sextants was also below 10% in each survey. However calculus formation and bleeding on probing were very frequent findings both in Western and Eastern Europe. In the age group 35-44 the average prevalence of 'score 4 sextant' in Western and Eastern Europe were comparable while the proportion of periodontally absolutely healthy individuals was lower in Eastern Europe than in the Western part of the Continent. Five to 20% of the populations are affected by destructive periodontitis at the age of 40. This indicates the magnitude of the disease as a public health problem both in the industrialised West and the Eastern European countries. The same 10-15% prevalence rate of destructive periodontitis imposes a great challenge to the health authorities of these post-communist countries amid social and economic transition, because the nationwide preventive and basic periodontal therapeutic measures should be managed and financed from a substantially lower GDP than in the industrialised West.

Presence of oxytalan fibers in human regenerated periodontal ligament.

The aim of the present study was to investigate whether oxytalan fibers are formed in the regenerated human periodontal ligament. 6 patients, each of them exhibiting an advanced intrabony defect, were treated with a bioresorbable membrane according to the GTR-principle. Following a healing period of 6 months, the teeth were extracted together with their surrounding soft and hard tissues and subsequently fixed in 10% buffered formalin. Following decalcification in EDTA, the specimens were embedded in paraffin and 8-microm histological sections were cut in the mesio-distal direction, parallel to the long axes of the teeth. The sections were stained with hematoxylin and eosin, or with the oxone-aldehyde-fuchsin-Halmi staining method and examined in the light microscope. A regenerated periodontal ligament containing newly-formed oxytalan fibers was observed in all specimens. Many of them inserted into the newly formed cementum on the root surface. It is concluded that oxytalan fibers are formed de novo in human regenerated periodontal ligament tissue.

[The effect of smoking on the spread and frequency of periodontal disease]. / A dohányzás hatása a fogágybetegség elterjedtségére és gyakoriságára.

In recent years substantial data accumulated in the literature supporting the direct detrimental effect of tobacco smoking on periodontal health. The significantly inferior periodontal condition of smokers cannot be solely attributed to poor oral hygiene, increased calculus formation and altered subgingival microflora. Smoking imposes a direct threat to the periodontal tissues. Smokers with excellent oral hygiene show significantly less periodontal bone height and attachment level than matches non-smokers. Smoking entails a 2.5 to 3.5 risk ratio for severe periodontal attachment loss. Smoking also interferes with the outcome of nonsurgical and surgical periodontal treatment and impairs periodontal regeneration. The pathomechanism of the tobacco smoking related periodontal destruction is just partly understood. Tobacco products can alter normal host responses to neutralize infections and can also stimulate pathologic mechanisms to destroy the surrounding tissues. Tobacco products can directly impair polymorphonuclear leukocyte functions. Smokers have less salivary IgA and decreased serum IgG concentration as well as depressed number of helper T lymphocytes. Consequently smoking today is considered as one of the major risk factors for destructive periodontitis. Periodontitis is also considered as a decisive risk factor for systemic diseases especially for cardiovascular disorders. A strong association has been shown between periodontal disease and coronary heart diseases, as well as between periodontal disease and cerebrovascular diseases (stroke). The subgingival microflora and the continuous latent bacteremia and endotoxemia originated from the periodontal pockets might be responsible for the damage of the vascular endothelial integrity, platelet functions and blood coagulation. Modern periodontal epidemiology rediscovered the old ide of "focal infections" and indicated that the general health has a crucial impact on the periodontal health and periodontal disease has also a major impact on the general health status of the patient.

[Laboratory and clinical investigation of multifunctional dentifrices. Clinical study of a new triclosan-containing toothpaste]. / Multifunkcionális fogkrémek laboratóriumi és klinikai vizsgálata. Egy új Triclosan-tartalmú fogkrém klinikai kipróbálása.

The purpose of this work was to assess the in vitro antibacterial effectiveness of three dentifrices containing antimicrobial agents and to test the in vivo anti plaque and anti gingivitis effect of a toothpaste containing triclosan (CAOLA). The in vitro tests showed a marked antibacterial effect of both triclosan and chlorhexidine containing dentifrices. The randomized clinical trial presented good evidences that the triclosan had some but statistically non significant plaque and gingivitis reduction in patients even without previous mechanical cleaning. Nevertheless the triclosan dentifrice was effective in reducing the plaque and gingivitis scores in combination with initial mechanical debridement and oral hygienic instructions.

GTR with three different types of membranes in the treatment of intrabony periodontal defects: three-year results in sixty consecutive cases.

The aim of the present study was to evaluate the clinical results at 3 years following treating intrabony periodontal defects with different nonresorbable and bioabsorbable membrane barriers. Sixty intrabony periodontal defects were treated according to the principles of guided tissue regeneration (GTR). Twenty pockets were treated with Gore Resolut, a bioabsorbable membrane; 20 were treated with Gore-Tex, a titanium-reinforced membrane; and 20 with nonresorbable Gore-Tex membrane (all manufactured by Gore Regenerative Technologies, Flagstaff, AZ). The therapeutic results were evaluated by assessing probing pocket depth (PPD), recession of the gingival margin (GR), and clinical attachment level (CAL) at baseline, at 1 and at 3 years after therapy. The postoperative phase was uneventful in all cases. At 1 year after surgery, the results showed a mean PPD reduction from 9.42 mm to 3.35 mm (p < 0.0001) with Resolut; from 10.30 mm to 4.00 with titanium-reinforced Gore-Tex (p < 0.0001); and from 8.40 mm to 3.73 mm (p < 0.0001) with Gore-Tex membranes. The mean GR increased from 1.92 mm to 3.70 mm (p < 0.001) with Resolut; from 0.47 mm to 2.85 mm (p < 0.0001) with titanium-reinforced Gore-Tex; and from 0.73 mm to 2.15 mm (p < 0.0001) with Gore-Tex membranes. The mean CAL changed from 11.35 mm to 6.92 mm (p < 0.001) with Resolut; from 10.78 mm to 6.85 mm (p < 0.0001) with titanium-reinforced Gore-Tex; and from 9.13 mm to 5.87 mm (p < 0.0001) with Gore-Tex membranes. The clinical results at 3 years were not significantly different when compared with the 1-year results (p > 0.05). No significant differences existed between the mean changes in PPD, GR, and CAL in the three different test groups. Furthermore, one tooth scheduled for extraction for periodontal and prosthodontic reasons was treated with Resolut. Histological analysis 6 months after treatment demonstrated the neoformation of a connective tissue attachment and of new alveolar bone. This additional evidence thus proved that treatment with bioabsorbable membranes according to GTR principles delivers not only clinical improvement, but also histological periodontal regeneration.

Healing of human intrabony defects following treatment with enamel matrix proteins or guided tissue regeneration.

The aim of the present study was to evaluate histologically in humans the healing of advanced intrabony defects following treatment with enamel matrix proteins (EMD) or guided tissue regeneration (GTR). Fourteen patients, each of them displaying 1 advanced intrabony defect around teeth scheduled for extraction were included in the study. The defects were treated randomly either with an enamel matrix protein derivative (Emdogain, BIORA AB, Malmö, Sweden) or with a bioabsorbable membrane (Resolut, Regenerative Material, W.L. Gore & Assoc., Flagstaff, Arizona, USA). At baseline the mean probing pocket depth (PPD) in the EMD group was 11.3 +/- 1.8 mm and the mean clinical attachment level (CAL) 12.1 +/- 2.0 mm, whereas in the GTR group the mean PPD was 11.4 +/- 2.2 mm and the mean CAL 13.3 +/- 2.3 mm. Healing was uneventful in all cases. Neither allergic reactions against EMD or the bioabsorbable membrane, nor suppuration or abscesses were observed. The clinical results revealed at 6 months in the EMD group a mean PPD of 5.6 +/- 1.3 mm and a mean CAL of 9.1 +/- 1.5 mm. In the GTR group the mean PPD was 5.6 +/- 1.3 mm and the mean CAL 10.1 +/- 1.5 mm. The histological analysis showed in the EMD group a mean 2.6 +/- 1.0 mm of new attachment (i.e. new cementum with inserting collagen fibers) and a mean 0.9 +/- 1.0 mm of new bone. In this group, the formation of new attachment was not always followed by bone regeneration. In the GTR group, the mean new attachment was 2.4 +/- 1.0 mm and the mean new bone 2.1 +/- 1.0 mm. In every case treated with GTR, the formation of new attachment was followed by a varying amount of new bone. After both types of regenerative treatment the newly formed cementum displayed a predominantly cellular character. The findings of the present study indicate that the treatment of intrabony defects with enamel matrix proteins or with bioabsorbable membranes enhances the formation of a new connective tissue attachment in humans.

[Clinical experience with the treatment of gingival hyperplasia induced by calcium channel blocking agents]. / A kalcium-csatorna-blokkoló szerek okozta ínyhyperplasia kezelésének klinikai tapasztalatai.

The prevalence of the nifedipine-induced gingival hyperplasia is ranging from 0.5-83% in the dental literature. The pathomechanism of the nifedipine-induced gingival hyperplasia is not clearly understood. Evaluating the dental history and the course of disease of 34 patients treated and followed up at the Department of Periodontology the following answers were raised: What sort of local and systemic factors are enhancing the recurrence of the gingival overgrowth and how this can be anticipated in patients on continuous Ca channel blocking medication. Eight out of the 34 patients participating in the clinical trial did not remember the onset of their gingival overgrowth. 10 cases developed three years and three cases after less then one year of the onset of the drug administrations. 27 out of the 34 cases required gingival surgery and seven showed good clinical improvement after the hygienic phase of the comprehensive periodontal treatment. 70% of the gingival hyperplasia cases presented no clinical sign of recurrence one year after the completion of the active phase of the treatment. A positive correlation was found between the oral hygiene and the recurrence rate of gingival overgrowth. Oral hygiene seems to play a decisive role in the development of gingival enlargement. The present findings and substantial evidences from the dental literature indicate that the gingival enlargement can be successfully controlled even under the continuous nifedipine administration by meticulous professional and individual oral hygiene.

[A 3-year experience with guided tissue regeneration procedures]. / Az irányított szövetregenerációs technikákkal nyert három éves klinikai tapasztalatok.

The Guided Tissue Regeneration (GTR) procedures are promoting a clinically and radiologically as well as histologically verifiably periodontal attachment gain. The objective of the study was to evaluate the clinical efficacy of these GTR techniques. In the past four years different barrier membranes (Gore-tex, Resolut and Guidor) were used around 318 teeth of 196 patients. 169 periodontal defects of 140 patients were followed up at least for two years. 54 patient had chronic adult type periodontitis, 67 suffered with rapidly progressing periodontitis and 15 had different severe mucogingival lesions. 111 vertical bony defects, 43 Class II-III furcation lesions and 15 mucogingival lesions were surgically corrected. The average preoperative probing depth (PD) and the clinical attachment loss (CAL) of the vertical bony defects were 5.3 +/- 1.7 mm and 6.2 +/- 1.9 mm respectively. The PD of the deepest Class III furcation lesion was 11 mm. The average gingival recession of the mucogingival lesions was 4.5 +/- 1.1 mm. The GTR technique provided the best results in the Class II-III furcation lesions, where an average 2.4 +/- 0.9 clinical attachment gain was observed one year postoperatively. The GTR techniques provided an average 1.8 +/- 1.2 mm attachment gain in the vertical bony crater cases. In both groups of cases a marked gingival recession followed the healing and the periodontal regeneration. In this way the average reduction in the probing depth exceeded the average attachment gain by more that 1.5 mm. 1 year after the operation the average radiologic bone fill was about 0.9-1.2 mm. The resorbable barrier membranes resulted in clinically significant root coverage and an average 3.5 +/- 1.7 mm gain in the width of keratinized gingiva. The success or failure of our cases were mainly determined by the patient's compliance, the level of the postoperative professional and individual oral hygiene and the number of periodontal recalls. These findings are also underlining the importance of the high standard of oral hygiene in the postoperative periodontal regeneration.

[The effect of certain stages of periodontal treatment on the regeneration of periodontal tissues]. / A komplex parodontális kezelés egyes lépéseinek hatása a parodontális szövetek regenerációjára.

The regenerative potential of the periodontal tissues is relatively limited. The attachment loss has long been considered as an irreversible damage of the periodontium. Most of the conventional methods of the comprehensive periodontal treatment provided no convincing evidence of true new periodontal attachment formation. Most of the surgical and nonsurgical approaches achieved either secondary gingival recession and/or long epithelial attachement. The recently introduced guided tissue regeneration techniques can make the regeneration of the fibrous periodontal attachment and convincing clinical and histological evidences of new cementum and bone formation possible, as well as the regeneration of the perpendicular Sharpey's fibers fully embedded into the matrix of the appositionally formed new cementum and bone. The theories and clinical implications of these techniques are discussed and illustrated with clinical cases.

[The role of sensitivity of oral hygiene indices in the selection of proper methodology of plaque-control clinical studies]. / A szájhigiéniás indexek érzékenységének szerepe a plakk-kontroll klinikai vizsgáló módszereinek kiválasztásában.

UNLABELLED: A double blind split-pilot study was carried out to test the potential increase in sensitivity of the Quigley and Hein (Turesky modification) plaque index using a six site recording technique against the two site technique in assessing the antiplaque effects of dentifrices. The study also evaluated the impact of asking the subjects not to brush their teeth the morning of the evaluations versus those who where hot given these instruction. The results indicated that the triclosan containing dentifrice had a significant anti-plaque effect over the placebo at 3 weeks when using both two (p = 0.003) and six (p = 0.002) sited plaque assessment methods. However the six-sited index demonstrated the greater efficacy for the active dentifrice. At six weeks no statistically significant difference between the two dentifrices was seen. The instruction of subjects not to brush before the plaque evaluation increased the mean plaque scores as well as the treatment effect at any time. IN CONCLUSION: The six-sited plaque index increased the sensitivity of the index in determining the anti-plaque efficacy of dentifrices, as well as indicating that instructing subjects not to brush preceding their plaque evaluations also increases sensitivity for determining anti-plaque efficacy of dentifrices.

[Hormonal regulation of bone metabolism]. / A csontanyagcsere hormonális szabályozása.

During the past two decades our ideas about the regulation of bone formation and resorption has been expanded. At the cellular level we have learnt more about the hormonal control of the osteoblastic bone formation, the osteoclastic bone resorption and the role of the nonosseous cells in the bone metabolism. At the tissue level we have understood the coupling between osteoblastic bone formation and osteoclastic bone resorption and consequently the relation between bone turnover and skeletal growth, involution and pathologic bone changes. Though many of the findings of the recent bone researches have helped us to understand the pathogenesis of the metabolic and infectious bone diseases we do not yet have a reliable means for stimulating bone formation of structurally and functionally effective new bone in human beings. In this review we tried to summarize the research data and clinical observations showing the direct and indirect effect of calcium regulating hormones (PTH, 1,25 dihydroxyvitamin D and calcitonin) on bone metabolism.