A cross-sectional study on osteocalcin levels in gingival crevicular fluid from periodontal patients

Nonsurgical Treatment of Periodontitis in Menopausal Patients: A Randomized Control Trial

Background

Menopause is typically accompanied by significant systemic and oral manifestations, including hormonal changes and increased susceptibility to periodontal disease, which may involve inflammatory biomarkers like aspartate aminotransferase (AST) and osteocalcin in gingival crevicular fluid (GCF). The study is aimed at evaluating the effectiveness of regular inoculation of polyunsaturated fatty acids (PUFAs) as an adjunctive treatment for menopausal women's periodontitis.

Methods

Twenty elderly women with chronic periodontitis were split evenly into two groups by random assignment. Patients in group II (the research group) were given soft gelatin capsules containing PUFAs to be consumed directly once daily for 12 months, as opposed to group I (the control group), who received soft gelatin capsules containing some olive oil (placebo). Scaling and root planning (SRP) were used to address periodontal disease in all cases.

Results

At baseline, six and twelve months after treatment, clinical indicators and AST and osteocalcin amounts in the GCF were noted. By the conclusion of the research period, all observed clinical measurements had changed significantly and improved. In addition, there had been a significant decrease in AST levels and a nonsignificant decrease in osteocalcin levels in group II compared to group I.

Conclusions

Menopausal women with periodontitis who take omega-3 fatty acid supplements in addition to SRP have better oral health. Significant improvements in clinical indicators and a notable decrease in AST levels within the GCF were observed. However, further research with larger cohorts and extended duration is needed to validate these findings and explain potential mechanisms. This trial is registered with NCT06254118.

Full-mouth disinfection effects on gingival fluid calprotectin, osteocalcin, and N-telopeptide of Type I collagen in severe periodontitis

BACKGROUND

To compare the effects of full-mouth disinfection (FMD) and full-mouth ultrasonic debridement (FMUD) on clinical, microbiological and biochemical parameters with conventional quadrant-wise scaling and root planning (Q-SRP) in severe chronic periodontitis.

METHODS

In the present prospective randomized controlled clinical trial with three parallel arms (#NCT04038801), 60 chronic periodontitis patients were randomly assigned to three study groups by a consecutive number in ascending order: FMD (n = 20), FMUD (n = 20), and Q-SRP (n = 20). All measurements and treatments were performed by the same investigator. At baseline, gingival crevicular fluid (GCF) and subgingival plaque were collected and clinical periodontal parameters were recorded. Ultrasonic debridement was completed within 24 hours in FMD and FMUD groups. Chlorhexidine gluconate was used for FMD. Q-SRP was performed by hand instruments per quadrant at 1-week-intervals. Clinical measurements and sampling were repeated at 1, 3, and 6 months after treatment. Real-time PCR was used for quantitative analysis of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythia, Fusobacterium nucleatum, and total bacteria count. GCF Calprotectin, osteocalcin, and N-telopeptide of type I collagen (NTx) levels were analyzed by ELISA. The changes of GCF biomarker levels after treatment between groups were the primary outcomes.

RESULTS

No harm was observed. All treatment strategies resulted in significant improvements in all clinical parameters (P < 0.05), with no significant differences between study groups at all time-points (P ˃ 0.05). Aggregatibacter actinomycetemcomitans was significantly decreased in FMD compared to FMUD and Q-SRP at 6 months (P < 0.05). Although GCF NTx total amounts increased in all groups during the study period, this increase was less prominent in full-mouth groups at three time points after treatment (P < 0.05).

CONCLUSIONS

Present results represent the short-term effects. Full-mouth treatment approaches offered limited beneficial effects on microbiological and biochemical parameters over quadrant-wise approach. All three treatment strategies can be recommended in the management of severe chronic periodontitis.

Effect of Interproximal Caries in Primary Molars on Clinical Parameters and Levels of Some Biochemical Markers in Gingival Crevicular Fluid

This study aims to investigate the relationship between dental caries and periodontal health by examining the clinical parameters and levels of some biochemical markers in the gingival crevicular fluid (GCF) of the teeth. In 22 children, 22 maxillary primary canine teeth and a pair of primary molars in a total of 38 quadrants were examined. The control group (C) consisted of children who had at least 1 caries-free primary maxillary canine. The test group (T) consisted of children who had a pair of primary molars where the interproximal contact was lost due to the caries in the same quadrant. Their primary molars were restored with compomer. The teeth were evaluated based on clinical values (plaque index, gingival index, and probing depth) and biochemical values in GCF before (C₀, T₀) and after a 6-month treatment (C₁, T₁). While total amounts of interleukin-1 beta and vascular endothelial growth factor in GCF in T₀ were significantly higher than in C₀ (P < 0.001), osteocalcin was statistically insignificant (P > 0.05). Clinic parameters in T₀ were significantly higher than in C₀ and T₁. Also these parameters in C₀ were higher than in C₁ (P < 0.01). Clinical and biochemical parameters in GCF in the teeth with interproximal caries might show symptoms of periodontitis.

Biomarkers of oral inflammation in perinatally HIV-infected and perinatally HIV-exposed, uninfected youth

AIM

To examine oral biomarkers that have been associated with periodontal disease progression in HIV-infected adults in perinatally HIV-infected and HIV-exposed but uninfected youth.

MATERIAL AND METHODS

This was a cross-sectional, multicentre substudy of youth participating in the Oral Health Pediatric HIV/AIDS Cohort study. Gingival crevicular fluid repository samples from participants with and without periodontal disease (using Gingival Index [GI] and Bleeding on Probing [BOP] parameters on dental examination) were tested for concentration levels of inflammatory biomarkers. Associations were assessed using Wilcoxon test and Spearman correlation.

RESULTS

For perinatal HIV youth (n = 129), the markers consistently elevated (p < .05) in sites with GI ≥2 and in sites with BOP were interleukin-1β, 6 and 13, macrophage inflammatory protein-1α and metalloproteinase-9. Serum tumour necrosis factor-α and soluble CD14 were positively correlated with a summary count of elevated cytokines. No associations were seen among HIV-uninfected subjects (n = 71).

CONCLUSIONS

The association of oral biomarkers of inflammation with clinical indicators of periodontal inflammation and systemic immune activation suggests that perinatal HIV-infected youth may be at higher risk for developing significant periodontal disease, associated with tooth loss and HIV progression. More frequent dental care of this group is needed to prevent potential periodontal progression.

Detection of Ostecalcin in gingival Crevicular fluid in a Group of Orthodontic Patients

Aim:

To detect osteocalcin (OC) in gingival crevicular fluid (GCF) and to monitor the concentration of OC at what stage inflammation and bone resorption reaches their maximum following orthodontic activation.

Materials and Methods:

GCF samples were collected from six adult orthodontic patients (mean age = 22.3, range 20–24 years) on 3, 7, 10, 14, 21, 28, and 35 days after activation of orthodontic appliance, from the tooth surface where bone resorption was expected to occur. A total of 330 GCF sample were collected using filter paper strip, the volume measured by weighing. OC was analyzed using Enzyme-Linked immunoassay technique. Data were analyzed using the Statistical Package for Social Sciences software, SPSS (SPSS Inc., Chicago, IL, USA) version 15.

Results:

An increase in GCF volume and flow rate was noted in the 10^th day after activation of the orthodontic appliance activation; however, due to high-standard deviation, the result was not significant. OC was detected in all GCF samples. The amount and concentration were quite variable. Increase in the amount of OC was observed between days 7 and 14.

Conclusion:

OC was detected in all samples. The quantity of OC increased at day 10 in a number of samples. There was no obvious association between OC concentration and time of collection.

Bonebiomarkers in periodontal disease: a review article

Periodontitis, is an inflammatory state of the tooth supporting structures and if left untreated, the disease continues to progressive bone destruction and subsequent tooth loss. The increasing prevelance of periodontal disease paved way to the development of new diagnostic tests that could detect the presence of active disease,the course of the disease and its response to treatment. Bone is a metabolically active tissue and undergo continuous remodelling, a process that largely relies on the activity of osteoclasts to remove bone and of osteoblasts to form bone. In health ,bone resorption and formation are coupled to each other and its long term maintenance of skeletal balance is brought about by the systemic hormones and local mediators.In contrasts,during disease there is a pronounced in balance in bone turnover. Bone biomarkers which are produced either in health or in disease state are tell tale markers which would be used to monitor the health status. This review highlights, the recent advances in the use of biomarkers of bone remodelling,that could facilitate the screening, diagnosis and management of periodontal diseases.

Understanding the advances in biology of orthodontic tooth movement for improved ortho-perio interdisciplinary approach

This article provides an insight on detailed current advances in molecular understandings of periodontal ligament cells and the influence of orthodontic force on them in the light of recent advances in molecular and genetic sciences. It sequentially unfolds the cellular events beginning from the mechanical force initiated events of cellular responses to bone remodeling. It also highlights the risks and limitations of orthodontic treatment in certain periodontal conditions, the important areas of team work, orthodontic expectations from periodontal treatment and the possibility of much more future combined research to improve the best possible periodontal health and esthetic outcome of the patient.

Periodontal proteomics: wonders never cease!

Proteins are vital parts of living organisms, as they are integral components of the physiological metabolic pathways of cells. Periodontal tissues comprise multicompartmental groups of interacting cells and matrices that provide continuous support, attachment, proprioception, and physical protection for the teeth. The proteome map, that is, complete catalogue of the matrix and cellular proteins expressed in alveolar bone, cementum, periodontal ligament, and gingiva, is to be explored for more in-depth understanding of periodontium. The ongoing research to understand the signalling pathways that allow cells to divide, differentiate, and die in controlled manner has brought us to the era of proteomics. Proteomics is defined as the study of all proteins including their relative abundance, distribution, posttranslational modifications, functions, and interactions with other macromolecules, in a given cell or organism within a given environment and at a specific stage in the cell cycle. Its application to periodontal science can be used to monitor health status, disease onset, treatment response, and outcome. Proteomics can offer answers to critical, unresolved questions such as the biological basis for the heterogeneity in gingival, alveolar bone, and cemental cell populations.

Fluid dynamics of gingiva and gingival health in children with end stage renal failure

OBJECTIVES

Impaired homeostasis and fluid balance are important physiopathological alterations in patients with chronic renal failure which may adversely affect the fluid dynamics and health status of tissues and organs. There are insufficient data about this phenomenon in periodontal tissues. The aim of this study was to evaluate the fluid dynamics of gingiva in children with end stage renal failure (ESRF), correlating this entity with gingival health in the same patient group.

DESIGN

Fifteen paediatric ESRF patients undergoing peritoneal dialysis (test group) and 15 systemically healthy children (control group) who were without periodontitis participated in the study. Fluid dynamics of gingiva were assessed via the gingival crevicular fluid (GCF) volume and tissue osmotic pressure (GOP) levels in the groups. GCF volume was measured using a Periotron 8000, whereas GOP was measured using a digital osmometer. Silness and Löe Plaque index (PI) and, Löe and Silness gingival index (GI) scores were utilized to determine the gingival health status in the study population.

RESULTS

There were increases in the GCF volume and GOP of the test group compared to those of the control group (p<0.01). The PI and GI scores were higher in the test group than in the control group (p<0.01). Strong and positive correlations were found between GI and GCF volume, GI and GOP and, GCF volume and GOP in both groups (p<0.01).

CONCLUSIONS

Our findings suggest that the fluid dynamics of gingiva may alter in children with ESRF, and this phenomenon may consequently affect the gingival health of these patients.

Oral fluid-based biomarkers of alveolar bone loss in periodontitis

Periodontal disease is a bacteria-induced chronic inflammatory disease affecting the soft and hard supporting structures encompassing the teeth. When left untreated, the ultimate outcome is alveolar bone loss and exfoliation of the involved teeth. Traditional periodontal diagnostic methods include assessment of clinical parameters and radiographs. Though efficient, these conventional techniques are inherently limited in that only a historical perspective, not current appraisal, of disease status can be determined. Advances in the use of oral fluids as possible biological samples for objective measures of current disease state, treatment monitoring, and prognostic indicators have boosted saliva and other oral-based fluids to the forefront of technology. Oral fluids contain locally and systemically derived mediators of periodontal disease, including microbial, host-response, and bone-specific resorptive markers. Although most biomarkers in oral fluids represent inflammatory mediators, several specific collagen degradation and bone turnover-related molecules have emerged as possible measures of periodontal disease activity. Pyridinoline cross-linked carboxyterminal telopeptide (ICTP), for example, has been highly correlated with clinical features of the disease and decreases in response to intervention therapies, and has been shown to possess predictive properties for possible future disease activity. One foreseeable benefit of an oral fluid-based periodontal diagnostic would be identification of highly susceptible individuals prior to overt disease. Timely detection and diagnosis of disease may significantly affect the clinical management of periodontal patients by offering earlier, less invasive, and more cost-effective treatment therapies.

Systemic Low-Dose Doxycycline and Alendronate Administration and Serum Interleukin-1Beta, Osteocalcin, and C-Reactive Protein Levels in Rats

BACKGROUND

The aim of the present study was to evaluate the effects of systemic administration of low-dose doxycycline and a bisphosphonate, alendronate, on serum levels of interleukin-1beta (IL-1beta), osteocalcin (OC), and C-reactive protein (CRP) in experimental periodontitis in rats.

METHODS

Experimental periodontitis was induced by repeated injection of purified lipopolysaccharide (LPS) derived from Escherichia coli endotoxin. Forty-seven adult male Sprague-Dawley rats were divided into five study groups and given LPS, LPS + doxycycline, LPS + alendronate, LPS + doxycycline + alendronate, and saline control. At the end of the 1-week protocol, blood samples were obtained, and the rats were sacrificed. Serum samples were analyzed for IL-1beta, OC, and CRP concentrations by enzyme-linked immunosorbent assay (ELISA). The jaws were defleshed, and alveolar bone loss was assessed morphometrically. Data were evaluated statistically by non-parametric tests.

RESULTS

Morphometric measurements revealed significantly more bone loss in the LPS group compared to the saline control group (P <0.05). Alendronate revealed slight inhibition on alveolar bone loss either alone or in combination with doxycycline (alveolar bone loss: 0.41 mm in alendronate and combined drug treatment groups versus 0.45 mm in LPS and doxycycline groups). Significantly higher IL-1beta levels were observed with alendronate either alone or in combination with doxycycline than in the LPS group (P <0.05). Combined administration of doxycycline and alendronate showed significantly higher levels of OC than all of the other groups (P <0.01). Serum CRP levels did not exhibit significant differences between the study groups.

CONCLUSIONS

Alendronate either alone or in combination with doxycycline provided slight inhibition on LPS-induced alveolar bone resorption. The significantly increased serum OC level observed in the combined drug treatment group suggests that combined administration of alendronate and doxycycline might increase bone remodeling and thereby inhibit the progression of alveolar bone resorption in rats.

Relationship between gelatinases and bone turnover in the healing bone defect

PURPOSE

The aim of this pilot study was to determine the relationship between gelatinase (MMP-9 and MMP-2) markers of soft tissue inflammation/turnover at the bone/soft tissue interface and bone turnover (osteocalcin [OC], pyridinoline cross-linked carboxyl-terminal telopeptide of type 1 collagen [ICTP], and bone fill) during healing of an alveolar bone defect.

MATERIALS AND METHODS

Ten subjects undergoing oral surgery had a 5 x 5-mm trephine defect created on an edentulous ridge and were sampled at the bone/soft tissue interface at baseline (prior to flap reflection), 2 weeks and 12 weeks postsurgery, using a novel bone wash device. Recovered irrigants were analyzed for MMP-9 and MMP-2 by gelatin zymography, OC and ICTP with radioimmunoassays, and albumin (ALB; to normalize markers for blood content) with a sandwich enzyme-linked immunosorbent assay. Bone fill at 12 weeks was analyzed by radiographic absorptiometry.

RESULTS

All markers of enzymatic activity and bone turnover varied significantly across time (P < or = .03), with bone turnover markers OC and ICTP decreasing between baseline and 2 weeks, and MMP-9 and MMP-2 increased. Measures generally returned to near baseline levels after 12 weeks. MMP-9 versus MMP-2 (r = 0.97, P < .0001) and OC versus ICTP (r = 0.38, P = .048) were correlated with each other, while MMP-9 and MMP-2 were negatively correlated with ICTP (r = -0.48, P = .011 and r = -0.62, P = .006, respectively). MMP-9 was negatively correlated with subsequent bone fill (r = -0.63, P = .07).

CONCLUSIONS

Bone wash sampling showed that gelatinase activity at 2 weeks following creation of an alveolar defect appeared to decrease bone turnover and eventual bone fill, suggesting benefits for anti-MMP therapy during wound healing.

Diagnostic biomarkers for oral and periodontal diseases

This article provides an overview of periodontal disease diagnosis that uses clinical parameters and biomarkers of the disease process.This article discusses the use of biomarkers of disease that can be identified at the tissue, cellular, and molecular levels and that are measurable in oral fluids such as saliva and gingival crevicular fluid. Biomarkers identified from these biologic fluids include microbial, host response, and connective tissue-related molecules that can target specific pathways of local alveolar bone resorption. Future prospects for oral fluid-based diagnostics that use micro-array and microfluidic technologies are presented.

Serum, Saliva, and Gingival Crevicular Fluid Osteocalcin: Their Relation to Periodontal Status and Bone Mineral Density in Postmenopausal Women

BACKGROUND

Periodontitis and osteoporosis are characterized by the loss of bone mass. Osteocalcin levels have been postulated as a marker of inhibition of bone formation. The aim of the present study was to assess plasma, saliva, and gingival crevicular fluid (GCF) levels of osteocalcin and correlate them with periodontitis and osteoporosis.

METHODS

Seventy-three postmenopausal women, over 35 years old, were recruited for the study. Serum, saliva, and GCF osteocalcin were measured. Vertebral bone mineral density was measured by dual-energy x-ray absorptiometry. Differences between groups were assessed by analysis of variance (ANOVA), chi-square test, and non-parametric Kruskal-Wallis test.

RESULTS

Thirty-four (46.6%) were classified in the normal healthy bone group, 11 women (15.1%) in the osteopenic group, and 28 women (38.4%) in the osteoporotic group. No statistically significant differences between these densitometric groups were observed in probing depth (P = 0.24); clinical attachment level (P = 0.11); or mean osteocalcin concentrations in serum, saliva, and GCF. Twenty-seven (37.0%) of the women were classified without periodontitis (NPG) and 63.0% (N = 46) with periodontal disease (PG). There were no statistical differences in serum and saliva osteocalcin concentrations between these two groups. GCF osteocalcin concentrations were significantly higher in the PG women than in the NPG group (P = 0.008). Mean probing depth correlated significantly with GCF osteocalcin concentrations (r = 0.35; P = 0.002).

CONCLUSION

The results further support the concept that osteocalcin levels in GCF correlates with periodontal but not with osteoporosis status.

Local biochemical markers of bone turnover: relationship to subsequent density of healing alveolar bone defects

OBJECTIVES

This pilot study was designed to test whether biochemical markers of bone turnover in washes of periosteal or trabecular alveolar bone surfaces could be correlated with increases in bone density of an adjacent healing implant socket.

METHODS

Ten subjects had a canula inserted into the alveolar crest and sterile phosphate-buffered saline was washed over the periosteal and trabecular surfaces and collected. Surgical flaps were reflected, 5 mm diameter bone cores were removed from the bone wash site, and standardized radiographs were taken. The sites were allowed to heal for 12 weeks, and radiographs were repeated. Bone washes of the healing sites were also collected after 2 and 12 weeks. Washes were analysed for bone turnover markers osteocalcin (OC; radioimmunoassay) and C-terminal telopeptide of Type 1 collagen (ICTP; enzyme-linked immunosorbent assay (ELISA)), and blood component albumin (ALB; ELISA). Changes in bone density during healing were determined by radiographic absorptiometry.

RESULTS

OC/ALB and ICTP/ALB ratios were higher for trabecular than periosteal washes at baseline (p<or=0.01). Trabecular OC/ALB and ICTP/ALB were inversely correlated with increasing bone density of the healing bone core socket (r=-0.72, p=0.03; Pearson's correlation coefficient).

CONCLUSIONS

Biochemical markers of bone turnover in bone washes of specific alveolar bone sites may prove helpful in predicting how the bone density will increase around healing dental implants.

Position Paper: Diagnosis of Periodontal Diseases

At the present time, the diagnosis and classification of periodontal diseases are almost entirely based on traditional clinical assessments. Supplemental quantitative and qualitative assessments of the gingival crevicular fluid and subgingival microflora can potentially provide useful information about the patient's periodontal disease. In certain situations, these supplemental risk-assessment tests may be particularly valuable in establishing the endpoint of therapy prior to placing patients on a periodontal maintenance program. Although the clinical utility of none of these tests has been validated, their further development is warranted. A genetic test for susceptibility to periodontitis has become commercially available. How best to use this and future host-based tests in clinical practice remains to be determined. Probing depth and clinical attachment loss measurements obtained with periodontal probes are practical and valid methods for assessing periodontal status. Computer-linked, controlled-force electronic periodontal probes are commercially available and are currently in use by some practitioners. Many of the logistical problems associated with subtraction radiography are being overcome and this powerful diagnostic tool may soon come into widespread use. Future developments in this and other imaging techniques are likely to have a profound effect on our approach to the diagnosis of periodontal diseases.

Bone turnover markers in serum and periodontal microenvironments

BACKGROUND

Periodontitis is characterized by altered bone turnover, but local measurements are difficult.

OBJECTIVES

The objective of this study was to develop a method to measure multiple markers of bone turnover from single samples collected at various bone surfaces of the periodontium, and to test the ratios of these markers against more traditional serum and gingival crevicular fluid (GCF) samples.

MATERIALS AND METHODS

Fourteen subjects with untreated periodontitis were recruited for sampling serum, GCF (from sites > or = 5 mm probing depth that bled on probing) and washes of periodontal bone surfaces (adjacent interproximal, vestibular cortical and trabecular bone) with a novel irrigating device. All samples were analyzed for osteocalcin (OC, bone turnover marker; RIA), cross-linked N-telopeptide of type I collagen (NTx, bone resorption marker; ELISA) and albumin (Alb, serum protein; ELISA). Results were reported as ratios: OC/NTx to determine relative bone turnover, and OC/Alb or NTx/Alb to determine local OC or NTx production.

RESULTS

The OC/NTx ratio was significantly higher (p < or = 0.05) in serum vs. GCF (OC undetectable), interproximal bone and cortical vestibular bone, but significantly lower than in trabecular vestibular bone. The OC/Alb ratio for serum was also statistically lower than for vestibular trabecular bone. The NTx/Alb ratio for serum was statistically lower than for GCF and all the bone wash test sites. The results indicated considerable local production of both OC and NTx.

CONCLUSIONS

This system demonstrated that multiple markers of bone turnover can be harvested by irrigation from periodontal bone microenvironments. Bone turnover profiles from periodontal bone surfaces and GCF differed from systemic bone turnover profiles (serum) and may be valuable in tracking site-specific responses to disease or treatment.

Osteocalcin, deoxypyridinoline and interleukin-1beta in peri-implant crevicular fluid of patients with peri-implantitis

The aim of the present study was to analyze the levels of osteocalcin, deoxypyridinoline (Dpd) and interleukin-1beta as markers of bone metabolism in peri-implant crevicular fluid (PICF) from peri-implantitis patients. PICF was sampled from a total of 34 endosseous titanium implants from 16 patients; nine females (mean age 52.8, range 40-62 years) and seven males (mean age 56.0, range 36-66 years). The implants had been in place for a period of 9-112 months (mean; 35.8 months) since the loading. These sites were categorized as six peri-implantitis, eight peri-implant mucositis and 20 healthy implant. PICF volume from peri-implantitis sites was significantly higher than mucositis and healthy implant sites (P < 0.01). Osteocalcin levels in PICF from mucositis sites were significantly higher than healthy implants (P < 0.05), whereas peri-implantitis sites were not significantly different from either mucositis or healthy implant sites. Dpd could not be detected in any of the samples examined. IL-1beta levels in PICF from peri-implantitis sites were significantly higher than levels from peri-implant mucositis (P < 0.05) and healthy implant sites (P < 0.01). In conclusion, osteocalcin in PICF may reflect increased local bone turnover around implants. Further, IL-1beta should be a useful marker for peri-implant inflammation.

Mediators of periodontal osseous destruction and remodeling: principles and implications for diagnosis and therapy

Osteoclastic bone resorption is a prominent feature of periodontal disease. Bone resorption via osteoclasts and bone formation via osteoblasts are coupled, and their dysregulation is associated with numerous diseases of the skeletal system. Recent developments in the area of mediators of osteoclastic differentiation have expanded our knowledge of the process of resorption and set the stage for new diagnostic and therapeutic modalities to treat situations of localized bone loss as in periodontal disease. This review describes the current state of knowledge of osteoclast differentiation and activity, mediators, and biochemical markers of bone resorption and their use and potential use in clinical periodontics. Finally, therapeutic strategies based on knowledge gained in the treatment of metabolic bone diseases and in periodontal clinical trials are discussed, and the potential for future strategies is proposed relative to their biologic basis. The intent is to update the field of periodontics on the current state of pathophysiology of the osteoclastic lesion and outline diagnostic and therapeutic strategies with a rational basis in the underlying biology.

Evaluation of osteocalcin and pyridinium crosslinks of bone collagen as markers of bone turnover in gingival crevicular fluid during different stages of orthodontic treatment

Osteocalcin (Oc) and the collagen cross-links pyridinoline (Pyr) and deoxypyridinoline (dPyr) are used as markers of bone turnover in metabolic bone diseases. The aims of this study were: 1) to establish if Oc, Pyr and dPyr can be detected in GCF and 2) using the orthodontic tooth movement model of alveolar bone resorption to evaluate GCF levels of osteocalcin and these collagen cross-links as markers of bone breakdown. Plaque, colour and bleeding indices, probing measurements and GCF samples were collected at two sites in each of 20 adolescents, during 4 stages of fixed appliance therapy: (1) prior to appliance fit, (2) post appliance fit, (3) during active retraction of the maxillary canines, (4) during retention. GCF was collected onto filter paper strips and the volume determined by weighing. An ELISA kit was used for the detection of osteocalcin, whereas Pyr and dPyr were assayed using high performance liquid chromotography (HPLC). Wilcoxon signed ranks test and Bonferroni correction revealed statistically significant increases in plaque (p= 0.012), GCF volume (p=0.024) and osteocalcin concentration (p=0.012), between stages 1 and 2. There were no statistically significant differences between the other variables at this stage or between any of the variables at stages 2 and 3, or between stages 3 and 4. All but 3 of the GCF samples yielded detectable osteocalcin, with large site and subject variation. The median values of osteocalcin and osteocalcin concentration of all the samples were 87.5 pg and 66 pg/microl, with a range of 0-1,248 pg, 0-1,572 pg/microl. The detection of osteocalcin in GCF during every stage, the wide variation between subjects, and the lack of a consistent pattern related to stages of orthodontic treatment, suggests that osteocalcin may merely be a constituent of GCF associated with the developing dentition, which would reduce its potential as a marker of bone turnover in this group. None of the 16 GCF samples analysed for Pyr and dPyr gave a positive result. This study confirms that fitting an orthodontic appliance results in plaque accumulation and increased gingival inflammation, and that GCF volume is the most sensitive indicator of that inflammation. Osteocalcin was detected in GCF collected from adolescents, whereas Pyr and dPyr could not be detected. Further work is required to establish whether GCF osteocalcin levels can be used as a marker of bone turnover, and whether improvements in the sensitivity of detecting Pyr & dPyr make further study of these promising bone markers worthwhile.

Crevicular fluid osteocalcin and pyridinoline cross-linked carboxyterminal telopeptide of type I collagen (ICTP) as markers of rapid bone turnover in periodontitis. A pilot study in beagle dogs

The objective of this study was to correlate the levels of 2 putative markers of bone metabolism, namely osteocalcin and pyridinoline cross-linked carboxyterminal telopeptide of type I collagen (ICTP), to the progression of experimental alveolar bone loss in the beagle dog. 36 control sites and 36 experimental sites in 2 beagle dogs were assessed longitudinally at 2-week intervals for gingival crevicular fluid (GCF) osteocalcin and ICTP levels during a 6-month observation period. Analysis of osteocalcin and ICTP in GCF was performed by RIA. During the study, bone-seeking radiopharmaceutical uptake (BSRU) of 99mTc-MDP was assessed monthly; standardized radiographs were taken at 2-week intervals. The results showed osteocalcin and ICTP levels in GCF increased significantly (p < 0.05) by 2 weeks following initiation of disease. This increase preceded significant increases in BSRU by 2 weeks and radiographic evidence of bone loss by 4 weeks. BSRU was significantly elevated (p < 0.05) at experimental sites as compared to controls at 4 and 8 weeks post-disease initiation. Osteocalcin in GCF peaked 8 and 10 weeks after ligature placement in experimental sites at levels nearly 10-fold greater than contralateral paired control sites. ICTP levels in GCF remained elevated throughout the entire disease progression phase. Following the removal of ligatures, both GCF osteocalcin and ICTP levels dropped precipitously approaching control values. Osteocalcin revealed overall a positive predictive value (PPV) and negative predictive value (NPV) for future bone loss during disease progression of 0.87 and 0.34, respectively, while ICTP showed both high PPV and NPV of 0.87 and 0.91 respectively. Results from this study in the dog model indicate that osteocalcin and especially ICTP relate to indices of active periodontal bony destruction and suggest that these molecules may serve as predictive markers for future alveolar bone loss.

Identification and possible function of cathepsin G in gingival crevicular fluid from chronic adult periodontitis patients and from experimental gingivitis subjects

The levels of cathepsin G in gingival crevicular fluid (GCF) from chronic adult periodontitis patients and experimental gingivitis subjects were determined both by activity measurement using N-benzoyl-(DL)-phenylalanine-2-naphthyl ester as a substrate and by enzyme immunoassay using anti-human cathepsin G IgG. The activity level of cathepsin G in GCF of both periodontitis and experimental gingivitis has no significant correlation with all measured clinical parameters. Western immunoblotting using antibodies specific for cathepsin G or alpha 1-proteinase inhibitor revealed that the difficulty in demonstrating the association of its activity with the severity of these diseases was due largely to formation of the enzyme-inhibitor complexes. By contrast, statistically significant positive correlation was found between cathepsin G content in GCF of periodontitis, which was determined by enzyme immunoassay, and such clinical parameters as the GCF volume, the gingival index and probing depth. The increased cathepsin G content with increasing severity of periodontal inflammation was markedly diminished by the initial treatment. Although no significant activity was detectable in GCF of experimental gingivitis, a rapid increase of the immunoreactive cathepsin G was found in GCF at 3-5 d after refraining from oral hygiene measures, which rapidly decreased by 10 d. The progressively increased cathepsin G between 10th and 21st d rapidly decreased by cleaning of the teeth. The results indicate that cathepsin G is involved in the host's defensive mechanism against the invasion of etiologic microbes and/or the development of either periodontitis or gingivitis.