July06, 2022,UK

Reachus:+443455280535

Abstract Volume: 4 Issue: 3 ISSN:

Emerging Insight Into- “Precision Periodontics”

Uzma Irshad*


Corresponding Author: Uzma Irshad, Periodontist and Implantologist, Shifaa Hospital, Bengaluru, India.

BDS, Faculty of Dentistry, Jamia Millia Islamia, New Delhi.

MDS in Periodontics and Implantology, Rajiv Gandhi Institute of Health Sciences, Karnataka.

 

Copy Right: © 2022 Uzma Irshad. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Received Date: December 30, 2021

Published Date: January 06, 2022


Abstract

The longevity of people has increased globally along with an increase in comorbidities and medically compromised conditions. Periodontitis is among the most common health conditions that cause a major public health-related issue. With increasing prevalence, it has negative socio-economic impacts. Periodontitis-associated low-grade systemic inflammation shares the same pathological interplay with the systemic conditions that additionally raises awareness on the necessity for highly specific strategies for the prevention and management of periodontitis. Periodontal diagnosis is the backbone of a successful periodontal strategy since prevention and treatment plans depend on the accuracy and precision of the respective diagnostics.

Periodontal diagnostics is still based on conventional, clinical (pocket depth, clinical attachment loss, mobility) and radiological parameters (alveolar bone loss) that provide limited therapeutic guidance due to the multifactorial complexity of periodontal pathology, that is why biomarkers have been introduced in the new classification of periodontal and peri-implant conditions, 2017 as a pioneering step towards precision periodontics. Precision medicine is represented by biomarkers with the confluence of genomics, bioinformatics and digital technology.  With the lack of periodontal markers validated for diagnostic use, the implementation of a precision medicine approach in periodontology remains in the very initial stage. This review aims to elaborate on the foundations of individualized therapy meeting the diagnostic needs in periodontal diagnostics, the concept of precision periodontics, periodontal biomarkers, with future implementation of a precision medicine approach in periodontal practice.

Emerging Insight Into- “Precision Periodontics”

Introduction

With constant population growth and increased human lifespan, oral health strategies that have massively decreased the rate of tooth loss have expectedly resulted in an outbreak of periodontal diseases. Periodontitis represents a major public health problem. According to the Global Burden of Disease Study (2016), severe periodontal disease was the 11th most prevalent condition in the world.[1] The prevalence of periodontal disease was reported to range from 20% to 50% around the world.[2] It is one of the major causes of tooth loss which can compromise mastication, esthetics, self-confidence, and quality of life.[3,4] Hence, an immense efforts are made in the improvement of periodontal strategies for prevention and treatment, having their objective to minimize errors in diagnosis, improve outcomes, and avoid its negative socio-economic impacts with reduction in global periodontal burden. Diagnosis represents the backbone of successful periodontal treatment since the entire treatment plan, prognosis, and maintenance directly depends on the quality and precision of periodontal diagnosis. The crucial importance of accurate periodontal diagnostics extends far beyond clinical practice. Since periodontal diagnostics is still based on clinical and radiological parameters providing limited therapeutic guidance, the use of biomarkers has been introduced in the new classification of periodontal and peri-implant conditions, 2017 as a pioneer step towards the implementation of precision medicine concepts in periodontology.[5]

Precision medicine is a targeted treatment to a patient’s specific needs on the basis of genetic, biomarker, epigenetic, phenotypic, and socioeconomic or psychosocial determinants that distinguish an individual from others with similar clinical presentations. Unfortunately, there is no validated biomarker for diagnostic use in periodontology, and since biomarkers are the driving force of precision medicine, the implementation of a precision medicine in periodontics has been delayed. This review aims to elaborate the foundations of individualized therapy meeting the diagnostic needs in periodontal diagnostics, the concept of precision periodontics, periodontal biomarkers, with future implementation of a precision medicine approach in periodontal practice.


What is Precision Medicine- A brief Insight

The National Research Council’s Toward Precision Medicine [6] adopted the definition of precision medicine from the President’s Council of Advisors on Science and Technology in 2008 as: “The tailoring of medical treatment to the individual characteristics of each patient…to classify individuals into subpopulations that differ in their susceptibility to a particular disease or their response to a specific treatment. Preventative or therapeutic interventions can then be concentrated on those who will benefit, sparing expense and side effects for those who will not”. As the definition suggests, the power of precision medicine lies in its ability to guide health care decisions toward the most effective treatment for a given patient, and thus, improve care quality, while reducing the need for unnecessary diagnostic testing and therapies.


Historical Significance

••Eighteen years ago, the Human Genome Project completed the first draft of the 3 billion base pairs (i.e., A, C, T and G nucleotides or bases) that make up a person’s genomic DNA, that took a decade and nearly $300 million to complete a single person’s genome.[7,8]

••By 2013, sequencing a patient’s genome with annotation could be accomplished in less than a day for less than $1000 per genome.[9] 

••In 2015, U.S. President Barack Obama stated an amount of $215 million to the "Precision Medicine Initiative" of the United States National Institutes of Health.[10] A short-term goal of the Precision Medicine Initiative was to expand cancer genomics to develop better prevention and treatment methods. In the long term, the Precision Medicine Initiative aimed to build a comprehensive scientific knowledge base by creating a national network of scientists and embarking on a national cohort study of one million Americans to expand our understanding of health and disease.

The Mission Statement of the Precision Medicine Initiative read: "To enable a new era of medicine through research, technology, and policies that empower patients, researchers, and providers to work together toward development of individualized treatments". In 2016 this initiative was renamed "All of Us" and an initial pilot project had enrolled about 10,000 people by January 2018.[11]

 

Components of Precision medicine:

A precision medicine ecosystem ideally links patients, clinicians, clinical laboratories and researchers. Researchers generate new findings from the data derived from samples linked to digital phenotypes, family history and environmental exposures all captured as part of clinical care. Clinicians utilize a growing knowledge base curated from clinical laboratories.

Figure 1. The Precision Medicine Ecosystem

Figure 2. Bio-informatic technology role in Precision medicine


Limitation of Conventional Periodontal diagnostic techniques:

a) Clinical and radiological measurements of attachment loss are not precisely accurate

b) Full mouth recording is necessary because of the site-specific nature of periodontal disease progression.

c) Individual susceptibility to periodontitis varies both genetically and over time

d) All clinical diagnostic techniques provide information about past disease activity and are unable to diagnose present disease activity


Benefits of Precision Medicine over Conventional diagnostic techniques:

a)         Customize disease-prevention strategies

b)         Prescribe more effective drugs

c)         Avoid prescribing drugs with predictable negative side effects

d)         Reduce the time, cost, and failure rate of pharmaceutical clinical trials

e)         Eliminate trial-and-error inefficiencies that inflate health care costs and undermine patient care

f)          Shift the emphasis in medicine from reaction to prevention

g)         Predict susceptibility to disease

h)         Improve disease detection


Challenges In Periodontal Diagnosis

Periodontitis is a chronic multifactorial inflammatory disease triggered by dysbiotic biofilms leading to periodontal tissue destruction, clinically manifest as gingival bleeding, periodontal pocketing,  clinical attachment loss (CAL), radiological signs of alveolar bone loss and mobility [12] Technological progress in biomedicine, including highly sensitive diagnostic techniques, and machine learning algorithms, together with tremendous progress in periodontal research, has completely changed the face of periodontal pathogenesis and clearly revealed the limitations of the standard clinical approach in providing highly reliable and patient specific diagnostic information.

  • -> Periopathogen-centered theories have been replaced by the key-stone pathogen hypothesis of periodontal disease, depicting the dysbiotic changes within the periodontal microbiome triggered by key-stone periopathogens, rather than individual periopathogens.[13,14]
  • -> The withdrawal of aggressive periodontitis concept from the new classification system of periodontal disease is the best example, since highly sensitive molecular methods demonstrated that Aggreggatibacter actinomycetemcomitans, initially considered a form-specific pathogen, was present in less than 50% of aggressive periodontitis cases and showed a similar distribution between healthy and diseased patients.
  • -> With advancement in biofilm research, the complexity of biofilm structures have been revealed, the most prominent discoveries with clinical relevance are the importance of targeting the primary and secondary colonizers within preventive strategies.
  • -> Additionally, the interference between biofilm embedded bacteria with standard antimicrobial treatments and routine antibiograms has been demonstrated[15] emphasizing the need for anti-biofilm approaches and the use of advanced methods for microbial sensitivity, such as omics.
  • -> The role of non-periodontal pro-inflammatory factors, announced an immunological dysbiosis as a critical determinant of periodontal diseases.[16] Currently it is established that dysbiotic biofilms remain necessary but not sufficient to trigger periodontal diseases, while reinforced interactions between a dysbiotic microbiome and dysregulated inflammation are a hallmark of periodontal disease.[17] This concept has facilitated the understanding, identification, and confirmation of periodontal risk factors, such as the impact of viral and fungal species, systemic conditions, oral bad habits, hormonal changes, aging, and many other factors relying on inflammatory processes and their respective roles in local immunological breakdown and the deterioration of periodontal conditions.[18]
  • -> Finally, it is considered that the immunophenotype plays an important role in the severity of periodontitis[19], since it is considered that individuals with an overreactive genetic predisposition excessively react even to small amounts of bacterial biofilms, and this is particularly associated with periodontitis Stage 3 (previously called severe periodontitis) affecting up to 20% of the population.[20] Standard treatment protocols often fails to arrest progressive periodontal destruction as in Stage 3 periodontitis, while such patients exhibits low-grade systemic inflammation.[21,22]


Considering these facts altogether, it is clear that the multifactorial complexity of periodontal pathology exceeds the capacity of a standard clinical diagnosis in providing accurate diagnosis and requires biomarker-supported diagnostics. Requirements in periodontal diagnostics and its related precision approach should be: predictors and markers for periodontitis onset; markers for staging and grading of disease, prognostic markers for the treatment outcome of periodontitis; prognostic markers for patient specific treatment.


Precision Periodontics

Precision medicine is based on a combination of clinical parameters and biological markers reflecting the underlying biological processes; this enables highly reliable prediction of periodontal disease susceptibility, early diagnosis, prognosis, and planning of the most effective and safe treatment strategy meeting individual patient needs.[23] In vitro diagnostics (IVD) have set a breakthrough in this and accounts about 60% of all medical decisions today. IVD empowers clinicians to take decisions on highly specific and accurate diagnostic information and to customize a management strategy to fit individual patient needs.


Biomarkers in Precision Medicine

A biomarker is “a characteristic that is objectively measured and evaluated as an indicator of normal biological processes, pathogenic processes or pharmacological responses to a therapeutic intervention”.[24] A biomarker is a substance used to indicate a biologic state and is an objective measure to evaluate the present and future disease activity. Various biological media like saliva, serum and gingival crevicular fluid are used to determine biomarkers in periodontal health and disease. A single biomarker will not able to predict periodontal disease activity and severity. So combinations of biomarkers are used to predict the disease activity.[25]

Thanks to advancement in ‘OMICS’ technologies including epigenomics, genomics, exomics, transcriptomics, proteomics, metabolomics, salivomics and nascent fields such as viromics coupled with bioinformatics and biostatistics, generated and processed massive biological data. The concept of biomarkers relies on the measurement of regulators or byproducts of the biological processes of interest, starting from the cellular level, through intercellular interactions, to complex interplay within the tissues, organs, and organic systems. Such a diagnostic concept provides objectively measurable diagnostic information on the target biological processes in real time, compensating most common limitations of clinical parameters. With tremendous progress in biomedical technologies, practically any component of a biological process is measurable.


Biomarkers in Periodontics

Biomarkers in periodontology can be classified based on the requested diagnostic information and based on the biological type appropriate for the clinical strategy in order to provide diagnostic information specific to each clinical phase.

Figure 3. Biomarkers at various periodontal disease assessment and management stages

Figure 4. Biomarker in Periodontics based on Biological type

Table 1. Shows list of biomarkers seen in periodontal disease

 

Biomarkers in periodontology can also be categorized as follows:

••Predictive markers measured in healthy individuals in the disease prevention stage;

••Diagnostic markers of disease onset;

••Prognostic markers for the assessment of disease progression, stage, and grade in the treatment planning phase

••Diagnostic markers and surrogate endpoints used to estimate patient compliance with the administered treatment, stability of the therapy results, and disease activity in the maintenance phase


Predictive markers are used before disease occurrence for the identification of risk factors and estimation of the overall patient risk, aiming at adjustment of the screening protocol and related modification of risk factors for optimal disease prevention. For this purpose, static markers are usually used; these do not change over time and are typically genetic markers. Single-nucleotide polymorphisms (SNPs) are certainly the most studied class of genetical markers in periodontology, presenting as variations in single basepair components of DNA that determine host responsiveness to environmental changes. Periodontal pathogens and/or to inflammatory overreaction to pathogens, resulting in excessive periodontal destruction. For this reason, the cytokines and immunoreceptors responsible for pathogen recognition remain in the spotlight of genetic studies. SNPs in IL-1β, IL1RN, FcϒRIIIb, VDR and TLR4 genes may underline susceptibility to more destructive forms of periodontitis[26] while polymorphisms in the IL1β, IL1RN, IL6, IL10,VDR,CD14,TLR4 and MMP1 genes might be responsible for general susceptibility to chronic periodontitis.[27] However an extensive studies need to be done on large population to draw a conclusion.

Prognostic markers are measured when disease occurs; they do not need to change over time, and they serve to estimate disease characteristics, stage, and grade, which are indispensable for accurate prognostics of the progression pattern and responsiveness to different treatment protocols. The most frequently used are genetic markers. Therefore, prognostic markers should guide the clinician in the process of treatment planning to mitigate aggravating factors and minimize disease complications, in the selection of a suitable treatment protocol, and in setting the maintenance regimen for optimal treatment stability. IL-lα and IL-1β loci was associated with severe periodontitis.[28] IL1A and IL1B genetic variations are significant contributors to chronic periodontitis in Caucasians.[29] TNFα gene located on chromosome 6 within the major histocompatibility complex (MHC) gene cluster at the location 6p21.3 is associated with familial ability to produce higher or lower cytokine levels during periodontitis.[30]

Diagnostic markers comprise a wide group of indicators able to disclose disease onset, disease activity, and related disease progression, usually represented by fast-response biochemical and microbiological markers. A specific subset of diagnostic markers includes surrogate endpoints intended for estimation of the patient’s compliance to the administered treatment. These groups of biomarkers mostly comprise soluble inflammatory, soft tissue, and bone turnover markers (BTMs).[31] The inflammatory biomarkers in periodontology are represented by pro- and anti-inflammatory cytokines, host-derived enzymes, and markers of oxidative stress. Since these markers are elevated in both gingivitis and periodontitis, they are preferably used to estimate disease activity, progression, and compliance with administered treatment. Calprotectin inhibits immunoglobulin production and act as a proinflammatory protein. Increased expression of calprotectin at the site of inflammation offer protection against bacterial invasion to epithelial cells especially P.gingivalis.[32] Osteonectin plays a vital role in early phase of mineralization so it can act as a sensitive marker for detection of periodontitis. The sensitivity of this marker for diagnosing periodontal disease more when compare with N-propeptide of type I collagen.[33] Osteopontin helps in bone remodeling. In periodontitis, OPN levels are increased. There is a positive correlation between increased levels of OPN to probing pocket depth.[34,35] When nonsurgical periodontal treatment is provided GCF, OPN levels are significantly reduced.[36] Cathepsin-K, calprotectin, and osteocalcin also show a promising capacity for periodontitis diagnosis and predicting treatment outcomes.[37,38]

Soft tissue markers are used for monitoring soft tissue degradation and regeneration, and matrix metalloproteinases (MMPs) and growth factors are the most repurposed markers used in periodontology. Increased levels of MMP-8 are signifying conversion of gingivitis into periodontitis. No associations are found between MMP-8 levels and bone loss.[39] It is found that 18-fold increase of MMP-8 in patients experiencing active periodontal tissue breakdown as compared with patients under stable condition.[40] MMP-9 levels is reported in patients with recurrent attachment loss.[41] MMP-9 in oral diagnostics may best serve as a guide in periodontal treatment monitoring. Elevated levels of both MMP-13 and MMP-8 are correlate with irreversible peri-implant vertical bone loss around loosening dental implants.[33] In patients with untreated periodontal disease, collagenase present predominantly in the active form.[40] In the future, MMP-13 may be useful for diagnosing and monitoring the course of periodontal disease as well as tracking the efficacy of therapy. Platelet derived growth factor (PDGF) supports the healing. increased  Vascular endothelial growth factor (VEGF) expression in epithelial cells and endothelial cells in periodontitis-affected gingiva could be an useful marker for periodontal disease. Elevated rate of salivary Epidermal growth factor (EGF) secretion in aggressive patients may be associated with the pathogenic mechanisms of aggressive periodontitis.[42]

Bone turn over markers (BTMs) are considered the most important markers in periodontology to indicate inflammatory osteoclastogenesis onset and activity within periodontitis onset and activity, respectively. The RANKL/OPG relative ratio was proposed as a promising marker of periodontitis onset, but its diagnostic value in the assessment of disease activity has not yet been established.[43]

Microbiological markers, the real-time polymerase chain reaction (RTPCR) assessment of Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythia, Fusobacterium nucleatum, Treponema denticola, and Campylobacter rectus provides the most accurate information about periodontitis, its progression[44] and its responsiveness to administered treatment[45] while the diagnostic value of Aggregatibacter actinomycetemcomitans currently remains controversial.

Histopathological markers are not routinely used in periodontal diagnosis, but they may provide important information regarding the disease’s nature, pattern of progression, and grade and related to the validation of biomarkers most suitable for everyday use in the clinical setting.


Precision Periodontics- Where are we now??

New technologies for comprehensive biological profiling of patients have initiated a switch to precision periodontics[46]; however, this remains in the very initial stage. As mentioned above, the driving forces of precision medicine are validated biomarkers and machine learning algorithms, and so far, in periodontology, there is no biomarker validated for diagnostic use, while algorithms are predominantly exploited in observational studies (regression methods and clustering analyses) and rarely for diagnostic purposes. The confusing aspect of the lack of diagnostic markers in periodontology and implantology[47], despite so many reported biomarker studies, relates to a frequent misinterpretation of biomarkers specifically validated for diagnostic use. Biomarker validation studies aim to identify promising candidate markers to answer specific clinical requests, to standardize pre-analytical protocols (sampling and storage) and analytical protocols (laboratorial methods), and to provide highly accur Some common reasons for the lack of diagnostic markers in periodontology can be summarized as follows: High interstudy variability in clinical diagnostic criteria and case definition; small sample sizes; inappropriate study designs regarding candidate marker selection for specific diagnostic needs, clinical strategy, and data processing; variability in specimen collection and storage protocols and data reporting. Biomarkers validated for diagnostic use need to have a highly reproducible diagnostics protocol with established accuracy, sensitivity, specificity, false positive rate, false negative rate, and diagnostic range precisely disclosed in the diagnostic information; so far, these kinds of diagnostic studies have been scarce in periodontology and implantology[44,48]

In context of microbiological markers, diagnostic focus should be directed to the assessment of a panel of key-stone periopathogens, together with opportunists; recognized as a crucial diagnostic indicator in distinguishing health from disease, disease progression, and responsiveness to the performed treatment. It is thus expected that metagenomic and metatranscriptomic methods, together with culturomics[49] will contribute to the identification of highly specific microbiological markers for accurate diagnosis and prognosis of periodontal disease. In the context of assessing quantitative changes, quantitative RT-PCR is the method of choice, while quantitative omics-based methods are in a stage of development as well.

In the context of biochemical markers, proteomics is an analytical method that can contribute to the identification of highly specific cytokine panels, and different multiplexing methods enable the assessment of a great range of protein profiles.[48] BTMs are fast-response markers that reflect the nature and volume of the ongoing bone processes, practically enabling the clinician to visualize the bone status at the molecular level, far before clinical/radiological manifestations; this is valuable for early diagnosis of the conversion of gingivitis into periodontitis, early assessment of patient compliance with the administered treatment, and diagnosis of possible recurrence during maintenance care. The advanced “omics” methods that can particularly contribute to the identification of new bone markers are metabolomics, particularly regarding identification of the byproducts of bone destruction for real-time assessment of changes in the bone level over time or in response to treatment.

Histopathological studies will contribute to biological definitions of the grading criteria of periodontitis. Finally, the entire process of biomarker validation directly depends on the quality of the clinical aspect of diagnostic studies. Hence, strict adherence to the clinical diagnostic criteria and case definitions defined in the referent classification of periodontal conditions is the ultimate precondition for accurate validation of periodontal biomarkers.


Conclusion

Precision periodontics undoubtedly represents the future of high-quality periodontal care, so it is of paramount importance that future research studies strictly adhere to the recommendations for the validation of biomarkers in order to accelerate the process of their implementation in routine clinical practice. Future studies should focus on the development of biomarker assessment protocols applicable in everyday practice, such as point-of-care testing (POCT), which is still in the developmental stage in periodontology.[49,50] With the lack of periodontal markers validated for diagnostic use, the implementation of a precision medicine approach in periodontology remains in the very initial stage.


Funding: This research received no external funding.

Institutional Review Board Statement: Not applicable

Conflicts of Interest: The authors declare no conflict of interest.


References

1.Vos T, Abajobir AA, Abate KH, Abbafati C, Abbas KM, Abd-Allah F, Abdulkader RS, Abdulle AM, Abebo TA, Abera SF, Aboyans V. Global, regional, and national incidence, prevalence, and years lived with disability for 328 diseases and injuries for 195 countries, 1990–2016: a systematic analysis for the Global Burden of Disease Study 2016. The Lancet. 2017 Sep 16;390(10100):1211-59.

2.Sanz M. European workshop in periodontal health and cardiovascular disease. European Heart Journal Supplements. 2010 Apr 1;12(suppl_B):B2-.

3.Tonetti MS, Jepsen S, Jin L, Otomo?Corgel J. Impact of the global burden of periodontal diseases on health, nutrition and wellbeing of mankind: A call for global action. Journal of clinical periodontology. 2017 May;44(5):456-62.

4.Reynolds I, Duane B. Periodontal disease has an impact on patients' quality of life. Evidence-based dentistry. 2018 Mar;19(1):14-5.

5.Tonetti MS, Greenwell H, Kornman KS. Staging and grading of periodontitis: Framework and proposal of a new classification and case definition. Journal of periodontology. 2018 Jun;89:S159-72.

6.National Research Council. Committee on a framework for developing a new taxonomy of disease (2011) Toward Precision Medicine: Building a Knowledge Network for Biomedical Research and a New Taxonomy of Disease. DC: National Academies Press, xiii, 128pp [Google Scholar].

7.Davies K. The $1,000 genome: the revolution in DNA sequencing and the new era of personalized medicine. Simon and Schuster; 2015 Aug 18.

8.Collins FS, Hamburg MA. First FDA authorization for next-generation sequencer. New England Journal of Medicine. 2013 Dec 19;369(25):2369-71.

9.Slavkin HC, Navazesh M, Patel P. Basic principles of human genetics: a primer for oral medicine. health care. 2008;4:6.

10.Neergard L (30 January 2015). "Obama Proposes 'Precision Medicine' to End One-Size-Fits-All". Drug Discovery & Development. Associated Press.]

11.Cunningham PW. The Health 202: NIH wants 1 million Americans to contribute to new pool of gene data. Washington Post. January. 2018 Jan 16;16.

12.Papapanou PN, Sanz M, Buduneli N, Dietrich T, Feres M, Fine DH, Flemmig TF, Garcia R, Giannobile WV, Graziani F, Greenwell H. Periodontitis: Consensus report of workgroup 2 of the 2017 World Workshop on the Classification of Periodontal and Peri?Implant Diseases and Conditions. Journal of periodontology. 2018 Jun;89:S173-82.

13.Hajishengallis G, Lamont RJ. Beyond the red complex and into more complexity: the polymicrobial synergy and dysbiosis (PSD) model of periodontal disease etiology. Molecular oral microbiology. 2012 Dec;27(6):409-19.

14.Hajishengallis G, Darveau RP, Curtis MA. The keystone-pathogen hypothesis. Nature Reviews Microbiology. 2012 Oct;10(10):717-25.

15.Jacqueline C, Caillon J. Impact of bacterial biofilm on the treatment of prosthetic joint infections. Journal of Antimicrobial Chemotherapy. 2014 Sep 1;69(suppl_1):i37-40.

16.Hajishengallis G. Immunomicrobial pathogenesis of periodontitis: keystones, pathobionts, and host response. Trends in immunology. 2014 Jan 1;35(1):3-11.

17.Hajishengallis G, Chavakis T, Lambris JD. Current understanding of periodontal disease pathogenesis and targets for host?modulation therapy. Periodontology 2000. 2020 Oct;84(1):14-34.

18.Slots J. Focal infection of periodontal origin. Periodontology 2000. 2019 Feb;79(1):233-5.

19.Hernandez M, Dutzan N, García-Sesnich J, Abusleme L, Dezerega A, Silva N, Gonzalez FE, Vernal R, Sorsa T, Gamonal J. Host-pathogen interactions in progressive chronic periodontitis. Journal of dental research. 2011 Oct;90(10):1164-70.

20.Kassebaum NJ, Bernabé E, Dahiya M, Bhandari B, Murray CJ, Marcenes W. Global burden of severe periodontitis in 1990-2010: a systematic review and meta-regression. Journal of dental research. 2014 Nov;93(11):1045-53.

21.Nibali L, D'Aiuto F, Griffiths G, Patel K, Suvan J, Tonetti MS. Severe periodontitis is associated with systemic inflammation and a dysmetabolic status: a case–control study. Journal of clinical periodontology. 2007 Nov;34(11):931-7.

22.Slots J. Primer on etiology and treatment of progressive/severe periodontitis: A systemic health perspective. Periodontology 2000. 2020 Jun;83(1):272-6.

23.Korte DL, Kinney J. Personalized medicine: an update of salivary biomarkers for periodontal diseases. Periodontology 2000. 2016 Feb;70(1):26-37.

24.Biomarkers Definitions Working Group, Atkinson Jr AJ, Colburn WA, DeGruttola VG, DeMets DL, Downing GJ, Hoth DF, Oates JA, Peck CC, Schooley RT, Spilker BA. Biomarkers and surrogate endpoints: preferred definitions and conceptual framework. Clinical pharmacology & therapeutics. 2001 Mar;69(3):89-95.

25.Reddy S, Kaul S, Prasad MG, Agnihotri J, Asutkar HG, Bhowmik N. Biomarkers In Periodontal Diagnosis:" What The Future Holds...". International Journal of Clinical Dental Science. 2011;2(1).

26.Aleksic Z, Milasin J, Perunovic N. Promoter Polymorphism as a Susceptibility Factor for Multiple Gingival Recessions. Int J Periodontics Restorative Dent. 2015;35:263-9.

27.Laine ML, Crielaard W, Loos BG. Genetic susceptibility to periodontitis. Periodontology 2000. 2012 Feb;58(1):37-68.

28.Kornman KS, Page RC, Tonetti MS. The host response to the microbial challenge in periodontitis: assembling the players. Periodontology 2000. 1997 Jun;14(1):33-53.

29.Karimbux NY, Saraiya VM, Elangovan S, Allareddy V, Kinnunen T, Kornman KS, Duff GW. Interleukin?1 gene polymorphisms and chronic periodontitis in adult whites: a systematic review and meta?analysis. Journal of Periodontology. 2012 Nov;83(11):1407-19.

30.Bayley JP, Ottenhoff TH, Verweij CL. Is there a future for TNF promoter polymorphisms?. Genes & Immunity. 2004 Jul;5(5):315-29.

31.Lindström FD, Folke LE. Salivary IgA in periodontal disease. Acta odontologica Scandinavica. 1973 Jan 1;31(1):31-4.

32.Kido JI, Nakamura T, Kido R, Ohishi K, Yamauchi N, Kataoka M, Nagata T. Calprotectin in gingival crevicular fluid correlates with clinical and biochemical markers of periodontal disease. Journal of clinical periodontology. 1999 Oct;26(10):653-7.

33.Kinney JS, Ramseier CA, Giannobile WV. Oral fluid-based biomarkers of alveolar bone loss in periodontitis. Annals of the New York academy of sciences. 2007 Mar;1098:230.

34.Sharma CD, Pradeep AR. Gingival crevicular fluid osteopontin levels in periodontal health and disease. Journal of periodontology. 2006 Oct;77(10):1674-80.

35.Kido JI, Nakamura T, Asahara Y, Sawa T, Kohri K, Nagata T. Osteopontin in gingival crevicular fluid. Journal of periodontal research. 2001 Oct;36(5):328-33.

36.Hans S, Mali AM. Estimation and comparison of osteopontin levels in plasma in subjects with healthy periodontium and generalized chronic periodontitis and its assessment after scaling and root planing. Journal of Indian Society of Periodontology. 2012 Jul;16(3):354.

37.Afacan B, Ç?narc?k S, Gürkan A, Özdemir G, ?lhan HA, Vural C, Köse T, Emingil G. Full?mouth disinfection effects on gingival fluid calprotectin, osteocalcin, and N?telopeptide of Type I collagen in severe periodontitis. Journal of Periodontology. 2020 May;91(5):638-50.

38.Garg G, Pradeep AR, Thorat MK. Effect of nonsurgical periodontal therapy on crevicular fluid levels of Cathepsin K in periodontitis. Archives of Oral Biology. 2009 Nov 1;54(11):1046-51.

39.Rai B, Kharb S, Jain R, Anand SC. Biomarkers of periodontitis in oral fluids. Journal of oral science. 2008;50(1):53-6.

40.Gangbar S, Overall CM, McCulloch CA, Sodek J. Identification of polymorphonuclear leukocyte collagenase and gelatinase activities in mouthrinse samples: correlation with periodontal disease activity in adult and juvenile periodontitis. Journal of periodontal research. 1990 Sep;25(5):257-67.

41.Teng YT, Sodek J, McCulloch CA. Gingival crevicular fluid gelatinase and its relationship to periodontal disease in human subjects. Journal of periodontal research. 1992 Sep;27(5):544-52.

42.Hormia M, Thesleff I, Perheentupa J, Pesonen K, Saxén L. Increased rate of salivary epidermal growth factor secretion in patients with juvenile periodontitis. European journal of oral sciences. 1993 Jun;101(3):138-44.

43.Belibasakis GN, Bostanci N. The RANKL?OPG system in clinical periodontology. Journal of clinical periodontology. 2012 Mar;39(3):239-48.

44.Kinney JS, Morelli T, Oh M, Braun TM, Ramseier CA, Sugai JV, Giannobile WV. Crevicular fluid biomarkers and periodontal disease progression. Journal of clinical periodontology. 2014 Feb;41(2):113-20.

45.Cosgarea R, Eick S, Jepsen S, Arweiler NB, Juncar R, Tristiu R, Salvi GE, Heumann C, Sculean A. Microbiological and host-derived biomarker evaluation following non-surgical periodontal therapy with short-term administration of systemic antimicrobials: secondary outcomes of an RCT. Scientific reports. 2020 Oct 1;10(1):1-6.

46.Harvey A, Brand A, Holgate ST, Kristiansen LV, Lehrach H, Palotie A, Prainsack B. The future of technologies for personalised medicine. New biotechnology. 2012 Sep 15;29(6):625-33.

47.Buduneli N, Kinane DF. Host?derived diagnostic markers related to soft tissue destruction and bone degradation in periodontitis. Journal of clinical periodontology. 2011 Mar;38:85-105.

48.Bostanci N, Belibasakis GN. Gingival crevicular fluid and its immune mediators in the proteomic era. Periodontology 2000. 2018 Feb;76(1):68-84.

49.He W, You M, Wan W, Xu F, Li F, Li A. Point-of-care periodontitis testing: biomarkers, current technologies, and perspectives. Trends in biotechnology. 2018 Nov 1;36(11):1127-44.

50.Ji S, Choi Y. Point-of-care diagnosis of periodontitis using saliva: technically feasible but still a challenge. Frontiers in cellular and infection microbiology. 2015 Sep 3;5:65.

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5