Biomarkers and Periodontal Regenerative Approaches

Advances in periodontal healing biomarkers

Periodontitis is the infectious-inflammatory disease of tooth-supporting tissues. Periodontal treatment, either non-surgical or surgical, aims to remove infection, reduce inflammation, eliminate tissue loss, and gain clinical attachment. Clinical and radiographic recordings are widely used and accepted as gold-standard methods in periodontal diagnostics. While these traditional methods allow clinicians to monitor and diagnose periodontitis, they cannot be used to estimate the course of periodontal healing, or predict the disease recurrence or estimate the treatment outcome. Early prediction of the long-term consequences of periodontal treatment would be a crucial and valuable information not only for the clinicians, but also for the patients. Rapid advancements during past few decades boosted the periodontal biomarker studies and various microbe- or host-derived biochemical markers have been suggested as diagnostic biomarkers of periodontitis. Yet, there is no consensus regarding the accuracy of diagnostic biomarkers to monitor treatment response or to predict prognosis. The aim of this chapter will be to describe the healing patterns of periodontal tissues after treatment and present the available evidence on biomarkers that can indicate or predict successful treatment outcomes.

Evaluation of Osteocalcin Level in Gingival Crevicular Fluid in Periodontal Intrabony Defects Treated with Autologous Platelet Rich Fibrin: Non-Randomized Experimental Study

Objectives

The aim of this non-randomized experimental study is to evaluate and correlate the gingival crevicular fluid osteocalcin levels with clinical and radiographic parameters in patients with intrabony defects treated with autologous platelet-rich fibrin.

Material and Methods

Thirty intrabony defects in 14 patients were treated with autologous platelet-rich fibrin with open flap debridement. Clinical and radiographic parameters were recorded at baseline and 9 months postsurgery. Gingival crevicular fluid (GCF) was collected prior to the surgery, 3 months, 6 months and 9 months postsurgery and was analysed for levels of osteocalcin using ELISA.

Results

All the clinical and radiographic parameters like plaque index (2.41 to 1.38) and gingival index (2.37 to 1.4) scores, probing pocket dept (6.43 to 3.78 mm), clinical attachment level (7.25 to 4.61 mm), relative attachment level (10.35 to 7.42 mm) and vertical depth (7.46 to 4.9), alveolar crest height (6.2 to 5.9), area of the defect (17.8 to 14.5) respectively showed improvement which was statistically significant (P < 0.001) except for the defect width (8.86 to 8.77) with P = 0.39. A moderate negative correlation was established between the GCF osteoclcin levels and the clinical and radiographic parameters at baseline and 9 months except for the % of defect fill which showed moderate positive correlation at 9 months (r = 0.55, P = 0.002).

Conclusions

The gingival crevicular fluid osteocalcin can serve as a potential bone turnover biomarker in periodontal regeneration. In addition platelet-rich fibrin has made it possible to define natural bone regeneration as well as improve the clinical and radiological parameters.

Advances in periodontal biomarkers

Due to technologic advancements, periodontology has witnessed a boost in biomarker research over the past three decades. Indeed, with the aid of omics, our understanding of the healthy periodontium, pathogenesis of periodontal diseases, and healing after periodontal treatment has improved significantly. Yet, the traditional methods, periodontal probing and radiographies, remain the most common methods to diagnose periodontal disease and monitor treatment. Although these approaches can produce reliable diagnostic outcomes, they generally detect disease only after significant tissue degradation thus making treatment outcome highly uncertain. Accordingly, laboratories worldwide have collaborated with clinicians to design accurate, rapid and cost-effective biomarkers for periodontal disease diagnosis. Despite these efforts, biomarkers that can be widely used in early disease diagnosis and for treatment outcome prediction are far from daily use. The aim of this chapter is to give a general overview on periodontal health and diseases, and review recent advancements in periodontal biomarker research. A second aim will discuss the strengths and limitations of translating periodontal biomarker research to clinical practice. Genetic biomarkers of periodontitis are not discussed as the available confirmatory data is scarce.

Sirt6 Activation Ameliorates Inflammatory Bone Loss in Ligature-Induced Periodontitis in Mice

Periodontitis is an inflammatory disease caused by microorganisms that induce the destruction of periodontal tissue. Inflamed and damaged tissue produces various inflammatory cytokines, which activate osteoclasts and induce alveolar bone loss and, eventually, tooth loss. Sirt6 expression suppresses inflammation and bone resorption; however, its role in periodontitis remains unclear. We hypothesized that Sirt6 has a protective role in periodontitis. To understand the role of Sirt6 in periodontitis, we compared periodontitis with ligature placement around the maxillary left second molar in 8-week-old control (C57BL/6J) male mice to Sirt6-overexpressing Tg (Sirt6Tg) mice, and we observed the resulting phenotypes using micro-CT. MDL801, a Sirt6 activator, was used as a therapy for periodontitis through oral gavage. Pro-inflammatory cytokines and increased osteoclast numbers were observed in alveolar bone tissue under periodontitis surgery. In the same condition, interestingly, protein levels from Sirt6 were the most downregulated among sirtuins in alveolar bone tissue. Based on micro-CT and CEJ-ABC distance, Sirt6Tg was observed to resist bone loss against ligature-induced periodontitis. Furthermore, the number of osteoclasts was significantly reduced in Sirt6Tg-ligated mice compared with control-ligated mice, although systemic inflammatory cytokines did not change. Consistent with this observation, we confirmed that bone loss was significantly reduced when MDL801, a Sirt6 activator, was included in the ligation mouse model. Our findings demonstrate that Sirt6 activation prevents bone loss against ligature-induced periodontitis. Thus, a Sirt6 activator may provide a new therapeutic approach for periodontitis.

Accuracy of aMMP-8 point-of-care test in indicating periodontal treatment outcomes in stage III/IV periodontitis: A 24-week follow-up study

OBJECTIVE

To analyse the correspondence between aMMP-8 PoC test results and the clinical endpoints of non-surgical periodontal treatment in stage III/IV periodontitis.

BACKGROUND

The diagnostic success of the active-matrix metalloproteinase-8 (aMMP-8) point-of-care (PoC) test has been demonstrated in various studies, but the evidence of its accuracy following periodontal treatment is limited.

MATERIALS AND METHODS

Altogether 42 stage III/IV grade C periodontitis patients were included in this prospective diagnostic study. Clinical periodontal indices were recorded, aMMP-8 PoC test was applied and mouthrinse was collected before and at 6, 12 and 24 weeks after non-surgical periodontal treatment. Quantitative aMMP-8 levels were determined with immunofluorometric assay (IFMA) for the verification of the PoC test results. The accuracy of the aMMP-8 PoC test was assessed using previously established clinical endpoints as references.

RESULTS

Sensitivity and specificity of aMMP-8 PoC test to indicate clinical endpoints were ranged as follows: Sensitivity 71.4% at baseline, 39.3%-42.4% at week 6, 28.6%-32.4% at week 12 and 35.3%-42.9% at week 24; specificity 64.3%-80% at week 6, 40%-57.1% at week 12 and 56%-64.3% at week 24.

CONCLUSIONS

The accuracy of aMMP-8 PoC test in identifying clinical endpoints after non-surgical periodontal treatment is reduced in relation to baseline. Individual healing patterns of each diseased pocket eventually limit the accuracy of the dichotomous aMMP-8 oral rinse test during the post-treatment period.

Human β-Defensins in Diagnosis of Head and Neck Cancers

Head and neck cancers are malignant growths with high death rates, which makes the early diagnosis of the affected patients of utmost importance. Over 90% of oral cavity cancers come from squamous cells, and the tongue, oral cavity, and salivary glands are the most common locations for oral squamous cell carcinoma lesions. Human β-defensins (hBDs), which are mainly produced by epithelial cells, are cationic peptides with a wide antimicrobial spectrum. In addition to their role in antimicrobial defense, these peptides also take part in the regulation of the immune response. Recent studies produced evidence that these small antimicrobial peptides are related to the gene and protein expression profiles of tumors. While the suppression of hBDs is a common finding in head and neck cancer studies, opposite findings were also presented. In the present narrative review, the aim will be to discuss the changes in the hBD expression profile during the onset and progression of head and neck cancers. The final aim will be to discuss the use of hBDs as diagnostic markers of head and neck cancers.

Molecular biomarker research in periodontology: A roadmap for translation of science to clinical assay validation

The number of studies that aims to apply host‐ or microbe‐derived biochemical biomarkers to periodontal disease diagnosis has increased significantly during the last three decades. The biochemical markers can reflect the presence, severity, and activity of periodontal diseases; however, heterogeneities in applied laboratory methods, data presentation, statistical analysis, and data interpretation prevent the translation of candidate host‐ or microbe‐derived biochemical biomarkers to clinical assay validation. Here, we propose a roadmap for making the research outcomes comparable and re‐analysable with the ultimate goal of translating research to clinical practice. This roadmap presents reporting recommendations for host‐ or microbe‐derived biochemical biomarker studies in periodontology. We aim to make essential elements of the research work (including diagnostic criteria, clinical endpoint definitions, participant recruitment criteria, sample collection and storage techniques, biochemical and microbiological detection methods, and applied statistical analysis) visible and comparable.