Predictive, preventive, personalised and participatory periodontology: ‘the 5Ps age’ has already started
© Cafiero and Matarasso; licensee BioMed Central Ltd. 2013
Received: 19 March 2013
Accepted: 6 May 2013
Published: 14 June 2013
An impressive progress in dentistry has been recorded in the last decades. In order to reconsider guidelines in dentistry, it is required to introduce new concepts of personalised patient treatments: the wave of predictive, preventive and personalised medicine is rapidly incoming in dentistry. Worldwide dentists have to make a big cultural effort in changing the actual ‘reactive’ therapeutic point of view, belonging to the last century, into a futuristic ‘predictive’ one. The first cause of tooth loss in industrialised world is periodontitis, a Gram-negative anaerobic infection whose pathogenesis is genetically determined and characterised by complex immune reactions. Chairside diagnostic tests based on saliva, gingival crevicular fluid and cell sampling are going to be routinely used by periodontists for a new approach to the diagnosis, monitoring, prognosis and management of periodontal patients. The futuristic ‘5Ps’ (predictive, preventive, personalised and participatory periodontology) focuses on early integrated diagnosis (genetic, microbiology, host-derived biomarker detection) and on the active role of the patient in which networked patients will shift from being mere passengers to responsible drivers of their health. In this paper, we intend to propose five diagnostic levels (high-tech diagnostic tools, genetic susceptibility, bacterial infection, host response factors and tissue breakdown-derived products) to be evaluated with the intention to obtain a clear picture of the vulnerability of a single individual to periodontitis in order to organise patient stratification in different categories of risk. Lab-on-a-chip (LOC) technology may soon become an important part of efforts to improve worldwide periodontal health in developed nations as well as in the underserved communities, resource-poor areas and poor countries. The use of LOC devices for periodontal inspection will allow patients to be screened for periodontal diseases in settings other than the periodontist practice, such as at general practitioners, general dentists or dental hygienists. Personalised therapy tailored with respect to the particular medical reality of the specific stratified patient will be the ultimate target to be realised by the 5Ps approach. A long distance has to be covered to reach the above targets, but the pathway has already been clearly outlined.
KeywordsPredictive periodontology Preventive periodontology Personalised periodontology Participatory periodontology Lab-on-a-chip Gas chromatographs Cone beam computed tomography Host-derived diagnostic markers Saliva Gingival crevicular fluid
The aim of this paper is to synthetically report actual information on the genetics, microbiology and immunology of periodontal disease related to biomarkers that can aid to have early diagnosis. Further biomarkers, coming out in the early destruction of periodontal tissues, will be equally reported and discussed. The present article is directed not only to dental operators (such as general dentists, periodontists, dental hygienists) but also to medical doctors in order to enlarge the discussion group and to share our experiences and ideas with as much colleagues as possible. Considering the large number of professionals we intend to approach with the present paper, it seems clear that we have to discuss some basic topics about periodontal disease before introducing the specific periodontal biomarkers field.
Periodontal unit as a multi-functional complex
The periodontium is defined as an anatomic and functional complex which constitutes the supporting tissue of the teeth. Each of the periodontal components has its very specialised function. Periodontal tissues are distinct in the (1) gingiva and (2) deep periodontium (periodontal ligament, cementum and alveolar bone).
The periodontal ligament (alveolo-dental ligament) is a specialised connective tissue situated between the cementum covering the root of the tooth and the bone forming the socket wall. The extremities of collagen fibre bundles are embedded in the cementum (Sharpey's fibres) on one side and in the alveolar bone on the other side. It ranges in width from 0.15 to 0.38 mm.
The cementum is the hard, avascular connective tissue covering the roots of the teeth that serves primarily to attach the principal periodontal ligament fibres. There are two principal varieties of the cementum classified on the basis of the presence or absence of cells: acellular extrinsic fibre cementum (primary cementum or acellular cementum) and cellular intrinsic fibre cementum (secondary cementum or cellular cementum). The acellular extrinsic fibre cementum extends from the cervical half to two thirds of the root. The high number of Sharpey's fibres inserting in it shows its fundamental function in tooth attachment. The cellular intrinsic fibre cementum is distributed along the apical third or half of the root and in furcation areas. It represents a reparative tissue.
The mineralised bone is made up of lamellae (lamellar bone). It includes two types of bone tissue, the bone of the alveolar process and the alveolar bone lining the socket referred to as the alveolar bone proper or ‘bundle bone’ that consists of intrinsic fibre bundles running parallel to the socket. Embedded within this bundle bone and perpendicular to its surface are Sharpey's fibres. The alveolar bone is a clear example of a structure-function relationship because it increases in conjunction with the development of the teeth and it is partially lost in the absence of a tooth. In conclusion, the principal function of deep periodontal tissues is to support the teeth in their sockets. In addition, periodontal tissues act as a sensory receptor necessary for the proper positioning of the jaws and the proper pressure to be exercised during mastication. The peripheral feedback coming from the periodontal ligament gives signals to the muscles, ear and temporomandibular joints about the quality of the food present under the teeth and, as a consequence, the information for the fine-tuning of masticatory pressure.
Periodontal diseases: the real infections of the oral cavity
Periodontitis as a manifestation of systemic disease
Necrotising ulcerative gingivitis/periodontitis
Abscesses of the periodontium
Combined periodontic-endodontic lesions
The most common periodontal diseases are gingivitis and periodontitis whose primary characteristics are synthetically reported below.
Chronic periodontitis (CP) affects up of 50% of the global population, especially older patients, but may occur in children too. In most cases, the rate of progression of chronic periodontitis is slow, and the amount of periodontal tissue destruction is generally commensurate with sub-gingival calculus and plaque amounts. CP is classified as localised when <30% of sites are affected and generalised when this level is exceeded (Figures 11 and 12).
Aggressive periodontitis (AP) is less common than the chronic form. In the primary dentition of 5–11-year-olds, the frequency ranges from 0.9% to 1.5% of subjects [6–8], and in the permanent dentition of 12–20-year-olds, the frequency ranges from 0.1% to 0.2% in Caucasian populations. AP generally affects younger patients causing rapid loss of attachment and bone destruction. The severity of periodontal tissue destruction is conflicting with the scarce amounts of microbial deposits. The reason of this destruction is the presence of elevated proportions of aggressive Gram-negative bacteria (Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis), the phagocyte abnormalities and the hyperresponsive macrophage phenotype (elevated secretion of prostaglandin E2 (PGE2) and interleukin-1 (IL-1)) in response to bacterial lipopolysaccharides (LPSs). Aggressive periodontitis has been sub-classified into localised and generalised forms [9, 10].
Localised aggressive periodontitis
Localised aggressive periodontitis (LAP) presents a circumpubertal onset. The first molar/incisor presents with interproximal attachment loss on at least two permanent teeth, one of which is the first molar, and involving no more than two teeth other than the first molars and incisors. Serum antibody response to infecting agents was detected in high quantity.
Generalised aggressive periodontitis
The genetic bases of periodontitis
The observation that inheritance was an important component in the development of periodontal diseases was proposed as early as 1935 . Investigations focused on genetic risk factors are currently characterising periodontal research in the genetic field.
Mutations and polymorphisms
Specific mutations cause the genetic basis of various syndromic conditions in which periodontitis is present
Lysosomal trafficking regulator gene
Leukocyte adhesion deficiency type 1
Leukocyte chain adhesion molecule CD18
Leukocyte adhesion deficiency type 2
Glucose diphosphatase-fucose transporter-1
Bacterial burden: a challenge for periodontal tissues
The average 200-lb (90 kg) human body carries around with it about 6 lb (2.7 kg) of bacteria. Some of them live in the oral cavity forming a huge source of bacteria: to give an idea, in 1 mm3 (1 mg) of dental plaque, 108 bacteria are present. The Human Oral Microbiome Database lists 1,200 predominant oral species, with the order of 19,000 phylotypes .
Principal constituents of dental plaque
Matrix of extracellular substance
Ions and trace elements
Ag, Mg, Co, Fe, Cu, Pb, Sn
The most frequent microbial species isolated in healthy gingiva, gingivitis and periodontitis
Fusobacterium nucleatum subsp. polymorphum
Fusobacterium nucleatum subsp. nucleatum
Aggregatibacter actinomycetemcomitans serotype a
Aggregatibacter actinomycetemcomitans serotype b
Fusobacterium nucleatum subsp. vincentii
Fusobacterium nucleatum subsp. nucleatum
Further and more recent studies have demonstrated that there are specific associations among bacterial species within dental plaque.
The green cluster (Campylobacter concisus, Eikenella corrodens, Actinobacillus actinomycetemcomitans serotype a).
The yellow cluster made up of a group of streptococci (Streptococcus mitis, Streptococcus sanguis, Streptococcus oralis).
The purple cluster (Actinomyces odontolyticus, Veillonella parvula).
The red cluster (P. gingivalis, Tanerella forsythia, Treponema denticola).
The orange cluster (Fusobacterium nucleatum subspecies, Prevotella intermedia, Prevotella nigrescens, Peptostreptococcus micros, Campylobacter rectus, Campylobacter showae, Campylobacter gracilis, Eubacterium nodatum, Streptococcus constellatus, Fusobacterium periodonticum).
Finally, Actinotmyces naeslundii genospecies 2 (Actinomyces viscosus), Selenomonas noxia and A. actinomycetemcomitans serotype b did not cluster with other species .
An epidemiologic study found out that close members of the same family were infected via saliva with A. actinomycetemcomitans strains of the same biotype and serotype . For this reason, prevention measures against periodontal pathogens must include the entire family members in order to prevent cross-infection .
The chronic and aggressive forms of periodontitis are not monoinfections.
Some microbiota are more important than others as aetiological agents of periodontitis.
Periodontal tissues as a ‘battlefield’ in the struggle against oral bacteria
The host-microbial balance constitutes the situation in clinically healthy periodontal tissue. Plaque accumulation and immunitary response can create an imbalance of the host-parasite relationship occurring in destructive periodontal lesion. In fact, the fight among bacteria and immunocompetent cells can devastate the battlefield, that is, the periodontium.
Epithelial compartment: PMN activation
PMN leukocytes represent the first line of defence forming a protective wall against microorganisms. Activated polymorphonuclear leukocytes can cause tissue damage as a result of their accumulation in epithelial tissues. Further damages can be caused by a variety of enzymes and oxygen metabolites that are released from their granules during the battle against microbes [20, 21]. Oxygen metabolites such as hydrogen peroxide (H2O2) and reactive oxygen radicals (OH−) that are released into the phagosome defensive immunitary reaction could paradoxically contribute to the tissue destruction. As a consequence, the junctional epithelium becomes filled with ulcers and allows the passage of bacteria and their products in the underneath connective tissue.
Connective compartment: macrophage activation
In the subsequent line of defence, macrophages (Mø) play a decisive role to restrict bacterial spreading in the connective tissue. Macrophages are an important source of lysosomal enzymes, cytokines and inflammatory mediators such as IL-1, TNF-α, PGE2 and transforming growth factor beta (TGF-β).
IL-1 is the principal inflammatory mediator released by LPS-activated macrophages, lymphocytes and fibroblasts. IL-1 stimulates Mø and fibroblasts to secrete PGE2; moreover, it causes osteoclastic differentiation and activation .
TNF-α, principally secreted by LPS-stimulated macrophages and lymphocytes, causes osteoclastic differentiation and activation .
PGE2 causes vasodilatation, vasopermeability and resorption of the alveolar bone. IL-1, TNF-α and PGE2 stimulate fibroblasts and Mø to release MMPs, urokinase plasminogen activator (u-PA), tissue inhibitor of metalloproteinases, PGE2, TGF-β and interleukin-1 receptor antagonist. As described below, disease severity appears linked to the existent equilibrium among different involved molecules. The u-PA causes plasminogen transformation in plasmin which activates MMPs, enzymes degrading the connective extracellular matrix. They can be detected in gingival crevicular fluid, particularly during the activity phase .
Bone compartment: osteoclast activation
Inflammation progresses in the apical direction involving the bone tissue. It is important here to highlight that bacterial plaque never gets in direct contact with the bone tissue and that ‘running away’ from the bacterial aggregate is always at least 2 mm in distance from it. Many substances (PGE2, IL-1, IL-6, TNF-α) secreted by Mø, fibroblasts, plasma cells and T lymphocytes are primarily involved in osteoclastic activation.
Environmental risk factors
Smoking and diabetes mellitus are the most frequent co-factors strongly associated with the aggravation of periodontitis. Other situations such as obesity, stress and osteoporosis have been identified as co-factors in the progression of periodontitis .
The contemporary consensus is that diabetic patients are at increased risk of periodontitis . Patients with type 1 (insulin-dependent) and type 2 (non-insulin-dependent) diabetes mellitus have been found to be equally at risk for periodontitis . The severity of periodontitis has been proved to increase with the onset of diabetes at a younger age as well as with poorer metabolic control of diabetes . It has been claimed that periodontitis is the sixth complication of diabetes, together with retinopathy, nephropathy, neuropathy, macrovascular diseases and altered wound healing . Diabetes mellitus is the only systemic disease positively associated with attachment loss with an odds ratio of 2.32 (95% confidence interval (CI) 1.17–4.60) . Some authors presumed a two-way relationship in which periodontal therapy can improve metabolic control in diabetic patients . In these studies, periodontal treatment was associated with a reduction in HbA1c levels, and moreover, inflammatory biomarkers decline with periodontal treatment [35–37]. In contrast, non-significant reduction in HbA1c values was recorded in several studies [38–40]. Very recently, a meta-analysis of nine intervention studies of 485 people with diabetes concluded that periodontal treatment could lead to a significant 0.79% (95% CI 0.19–1.40) reduction in HbA1c levels . A recent Cochrane review on the treatment of periodontal disease for glycaemic control in people with diabetes declared that further controlled studies are necessary to clarify the topic . These conflicting data are difficult to understand in order to clarify the influence of periodontitis in glycaemic control. Hence, supplementary controlled clinical trials appear urgent and necessary to definitely assess if periodontal therapy can improve metabolic control in diabetic patients.
Cigarette smoking is associated with a relative risk, ranging from 2.05 (95% CI 1.47–2.87) for light smokers increasing to 4.75 (95% CI 3.28–6.91) for heavy smokers, of developing periodontitis [33, 43].
The negative effect of smoking is dose dependent and cumulative .
The negative effect of smoking is marked in younger individuals .
Smoking affects the healing potential of periodontal tissues .
Smoking is associated with the recurrence of periodontitis during periodontal maintenance .
Obesity, stress and osteoporosis
Other conditions such as obesity, stress and osteoporosis have been involved as co-factors in the progression of periodontitis, even if the association appears weak and still debatable.
It has been suggested that obesity is a strong risk factor for periodontal tissue destruction  since adipose tissue represents much more than a fat accumulation. It produces cytokines and hormones, collectively called adipokines or adipocytokines, which may play a key role in modulating periodontitis .
An association between obesity and periodontal disease in humans was reported for the first time by Saito et al. . The authors estimated that the relative risk for periodontitis was 3.4 in persons with a body mass index of 25–29.9 kg/m2 and 8.6 in those with a body mass index of >30 kg/m2. These results were confirmed by other authors [51, 52]. Genco et al.  demonstrated that the severity of periodontal attachment loss was modulated by insulin resistance. In addition, it was reported that maintaining a normal weight was associated with a poorer frequency of periodontitis [54, 55].
The impact of stress on periodontal diseases has not yet been clarified. Stressful life events have been shown to modulate the endocrine and immune systems. Stressful life events could affect periodontal disease progression through (1) unhealthy behaviours (poor oral hygiene, increased tobacco smoking) and (2) pathophysiological factors (higher glucocorticoid and catecholamine levels) which affect bacterial, immunological, inflammatory and hormonal profiles, leading to an increased susceptibility to periodontal disease [56, 57]. Finally, in a systematic review, a positive relationship between stress and chronic periodontitis was confirmed .
Osteoporosis is a metabolic bone disorder characterised by the loss of bone mineral density, principally recorded in postmenopausal women. It has been proposed that osteoporosis could affect the alveolar bone leading to rapid resorption in periodontal women. In one study, 189 postmenopausal women were controlled over a 7-year period. An association between the loss of bone mineral density and increased risk of additional tooth loss was reported. In a review, it has been shown that 7 out of 17 studies reported a positive relationship between osteoporosis and clinical attachment loss. Eleven out of 19 studies found a positive association between osteoporosis and tooth loss . Other studies showed negative or equivocal results .
It can therefore be concluded that since many of the studies were uncontrolled and had small sample sizes, the validity of their conclusions needs to be confirmed. Thus, the association between osteoporosis and periodontitis in humans remains weak and still debatable .
Periodontology approaches the future: 5Ps for five diagnostic levels
In addition to the traditional instruments for periodontal diagnosis, in the next future, well-organised population screening protocols utilising chairside diagnostic biomarkers for periodontal disease will be disposable. With reference to this, the last section of the present paper will be focusing on the diagnostic tools currently utilised for periodontal diagnosis (the present time) and on the most promising diagnostic tools (i.e. biomarkers and high-tech instrumentations) that are going to enter in clinical periodontology (the next future).
The present time: a precise picture of a single periodontal patient's existing condition
Diagnostic imaging and periodontal charting provide a complete description of the patient's periodontal condition.
Diagnostic imaging: a fundamental step to assess the periodontal conditions of a single patient
Full-mouth series periapical X-rays
Periodontal charting: a complete status of the patient's periodontal health
Full-mouth plaque score
The full-mouth plaque score is defined as the percentage of sites where plaque is present divided by the number of sites examined.
Full-mouth bleeding score
The full-mouth bleeding score is defined as the percentage of sites bleeding with respect to the number of sites examined.
Probing pocket depth
Clinical attachment level
Clinical attachment level (CAL), formerly called probing attachment level, is assessed by means of a graduated probe and expressed as the distance in millimetres from the cement-enamel junction (CEJ) to the bottom of the periodontal pocket (Figures 25 and 26). The severity of the attachment loss may be considered mild (CAL = 1–2 mm), moderate (CAL = 3–4 mm) or severe (CAL ≥ 5 mm).
Recession (REC) is defined as the apical migration of the gingival margin. In most cases, it is due to gingival inflammation or incorrect (traumatic) tooth brushing. It is measured from the cement-enamel junction to the gingival margin by the use of a periodontal probe (Figure 26).
Bleeding on probing
Mobility and migration
Unphysiological mobility and migration are generally due to the reduction of periodontal support caused by bone resorption in consequence of periodontitis. Physiological forces (tongue, lips, occlusion, etc.) can cause the movement and migration of the tooth with reduced periodontium.
Halitosis is defined as the presence of unpleasant breath odour. Gram-negative bacteria are the primary pathogens responsible for oral malodour production. Other causes of halitosis are uncontrolled diabetes, gastrointestinal diseases, renal failure and diseases affecting the upper/lower respiratory tract.
The next future: hi-tech diagnostic tools and specific biomarkers to detect early periodontal damage
Knowledge in dentistry is estimated to double every 4–5 years in comparison with the 1950s when it was estimated to take 25 years for such an expansion . Enhancement in dental knowledge revealed genetic, microbiological and immunological mechanisms at the base of periodontal diseases. Point-of-care (POC) testing allows rapid diagnostic tests in which results can be obtained immediately rather than waiting days for outside lab results to arrive . Chairside tests (CSTs) belong to POC cluster of analysis. They can give an immediate indication on the dental health of a single patient to dental operators. CSTs based on saliva, gingival crevicular fluid, cell and bacteria sampling are going to be routinely used by periodontists for a novel approach to the diagnosis, monitoring, prognosis and management of periodontal patients. In the larger healthcare community, ‘dentists and oral health professionals may be positioned to expand the reach and impact of preventive medicine through the application of cost-effective and non-invasive oral fluid screening tests and referring patients for necessary medical care’ .
The European population is becoming progressively older.
Periodontitis generally strikes people older than 40 years.
Periodontitis can cause serious detriment of the stomatognathic organ.
It appears clear, therefore, that periodontitis has to be considered as a social disease since it affects millions of people in Europe, and consequently, strategies have to be organised by national and international health organisations in order to intercept and treat the disease before it can create serious damages to a large part of the European population. A similar situation has been recorded in the USA in which 31% of the population exhibited mild forms of periodontitis, 13% displayed periodontitis of moderate severity and 4% suffered from advanced periodontitis . In order to face this situation, we should modify our approach towards diseases. Today, the work of periodontists is considered as ‘a reactive effort’ in the sense that we wait until the patient is sick before responding; on the contrary, the futuristic 5Ps focuses on the early integrated diagnosis (genetic, microbiology, host-derived biomarker detection) with the intention to detect periodontitis at an earlier stage, when it is easier to be treated successfully.
First diagnostic level: (lab-on-a-chip, gas chromatographs, cone beam computed tomography)
To identify a periodontal initial lesion when it is not yet clinically detectable.
To intercept the so called ‘active phase’ of periodontitis.
Lab-on-a-chip prototypes, gas chromatographs and cone beam computed tomography are three categories of high-tech devices that will be used everyday for the diagnosis of periodontitis in the not too distant future.
LOCs deal with the handling of extremely small fluid volumes down to less than picolitres (microfluidics). Microfluidics represent the technology behind a new miniaturised analysis system for biological applications such as DNA amplification, purification and separation ; sequencing ; proteomic analysis ; and single-cell gene expression profiling . The use of microfluidic devices has a number of significant advantages such as smaller sample requirement (usually several nanolitres), reagents come with the chip and reduced reagent consumption (especially significant for expensive reagents, which is an important concern in clinical laboratories today) that means an immediate indication on the periodontal health of a single patient to dental operators . Finally, the fabrication techniques used to construct microfluidic devices are relatively inexpensive and very open to mass production.
Halitosis is a major concern to the general public and the source of a multi-million-dollar industry worldwide . Many patients affected by oral malodour often remain completely unaware of this fact, while others complain of halitosis even if no objective basis can be found: this situation has been defined as the ‘bad breath paradox’. Halitosis is caused by physiologic or pathologic conditions. Physiologic halitosis (the so-called ‘morning breath’) is caused by the stagnation of saliva that disappears with drinking, consumption of food or tooth brushing.
Principal volatile components responsible for oral pathologic halitosis
Volatile sulphur compounds
Hydrogen sulphide, methyl mercaptan
Short-chain fatty acids
The Halimeter® has been shown to be more sensitive to H2S than to methyl mercaptan and almost insensitive to dimethyl sulphide, whereas the Oral Chroma™ measures all three gases with equally high sensitivities .
Cone beam computed tomography
Second diagnostic level: genetic susceptibility
The largest part of the studies shows no correlations between the presence of disease markers and the tested SNPs in both the aggressive and chronic forms of periodontitis . The polymorphisms that seemed to be linked with periodontitis in different ethnic groups were associated with the Fc-gamma receptor genes. However, these polymorphisms of the same gene were found in both chronic periodontitis and aggressive periodontitis [87, 88]. A weak association between the SNP in interleukin-1 genes and chronic periodontitis was found in a recent meta-analysis . Interleukin-1 is a pro-inflammatory agent that is released by macrophages, lymphocytes, platelets and endothelial cells. The gene encoding this cytokine is assigned to chromosome 2q13–21 .
In 1997, Kornman et al. described a composite genotype formed by two polymorphic loci - interleukin-1A (−889) and interleukin-1B (+3954) - which are single-nucleotide polymorphisms that carry a C-T transition . Interleukin-1A (−889), however, was outdated by the investigation of the interleukin-1A (+4845) G-T dimorphism, in which the two loci comprising the periodontitis-associated genotype were found to be in linkage disequilibrium .
Third diagnostic level: bacterial infection
Elevated odds ratio in disease.
Conversion of disease to health when bacteria are suppressed.
Development of a host response.
Presence of virulence factors (capability to avoid host defences and to damage tissues).
Evidence from animal studies corroborating the observations in humans.
Support from risk assessment studies.
Following the above criteria, the consensus report of the World Workshop on Periodontitis  identified three bacterial species for which sufficient data have accumulated as causative factors for periodontitis: A. actinomycetemcomitans (recently renamed to Aggregatibacter actinomycetemcomitans) , P. gingivalis and Bacteroides forsythus (renamed to Tanerella forsythia) . The consensus report stated that A. actinomycetemcomitans is most often found in aggressive (‘early-onset’) periodontitis, whereas P. gingivalis and T. forsythia are found more frequently in chronic (‘adult-onset’) periodontitis. Moderate evidence to support an aetiological role was reported for C. rectus, E. nodatum, P. intermedia, P. nigrescens, Parvimonas micra (formerly Micromonas micros and Peptostreptococcus micros), the Streptococcus intermedius complex and T. denticola. Finally, an initial evidence included on the list of probable periodontal pathogens E. corrodens, enteric rods, Pseudomonas species, Selenomonas species and Staphylococcus species. This report received general acceptance by the periodontal community and is still regarded as valid.
Even if there are no sufficient microbiological evidences that could help us in distinguishing the different forms of periodontitis, it is clear that:
The chronic and aggressive forms of periodontitis are not monoinfections.
Some microbiota are more important than others as etiological agents of periodontitis.
For these reasons, it appears clear that the microbial testing of sub-gingival plaque could be a valid support for a correct diagnosis of periodontitis. The anaerobic culture test is the most sophisticated technique to analyse the composition of sub-gingival plaque. All cultivable microbial species in the sub-gingival sample can be detected, and proportions of the various pathogens can be established. Anaerobic culture testing allows the antimicrobial susceptibility testing of periodontal pathogens. Anaerobic culture testing is advised especially in the case of refractory periodontitis, atypical forms of pathogens or periodontitis, peri-implantitis and immunocompromised patients. In routine cases, a DNA-based chairside test (semi-quantitative polymerase chain reaction (PCR)) is indicated. Bacteria do not need to be viable; consequently, time is not an issue with the present test. The number of target bacteria is determined semi-quantitatively (0 to +++).
CSTs for bacteria detection provide information about the presence and relative importance of putative pathogens.
The periodontist has to follow the following steps in order to perform a correct DNA-based chairside test (semi-quantitative PCR) for bacterial plaque analysis:
Meticulous removal of supra-gingival plaque.
Sampling of sub-gingival plaque by the insertion of sterile paper points into the deepest pockets in each quadrant.
Sending samples to a specialised laboratory.
Fourth and fifth diagnostic levels: host response factors and tissue breakdown-derived products
At present, well-studied molecules associated with host response factors and with derived tissue destruction mediators have been proposed as diagnostic biomarkers for periodontitis . Many dental associations, such as the American Dental Association (ADA), recognise the importance of continued research on oral fluid diagnostics and welcome the development of rapid point-of-care tests that provide accurate measurements of clinically validated biomarkers. The ADA council ‘encourages dentists to take leadership roles in integrating the tests and related technologies into clinical practice, consistent with the best available scientific evidence’ .
Happen approximately at the same time.
Share the same modality of non-invasive sample collection.
Release biomarkers which can be detected in the same diagnostic medium (oral fluid, gingival crevicular fluid)
Oral fluid (whole saliva) as a diagnostic tool
Glandular-duct saliva: saliva secreted by the parotid, sub-mandibular, sub-lingual and minor salivary glands (2,000 ml/24 h) is obtained directly from the glandular ducts with specially designed collectors. Glandular-duct saliva contains predominantly secretory IgA.
Gingival crevicular fluid (GCF) is an exudate flushing from the gingival sulcus (0.5 to 2.5 ml/24 h). GCF is a versatile and non-invasive means to sample the biomarkers of inflammation and bone resorption in the oral cavity. GCF represents serum components overlaid with products from local physiologic or pathologic phenomena. In particular, pathologic phenomena such as connective tissue destruction and bone loss may have a diagnostic value [103, 104]. Whilst gingival crevicular fluid is the most appropriate diagnostic medium to use in analyses, it appears clear that the use of whole saliva is more practical even if reactants need to be highly sensitive since biomarkers are more diluted [105, 106].
Salivary biomarkers for periodontal disease
Most promising salivary biomarkers for the diagnosis of periodontal disease
Dipeptidyl peptidases II and IV
Host response modifiers
Tissue breakdown products
Alkaline phosphatase (host-derived enzyme)
Alkaline phosphatase is an enzyme produced principally by neutrophils and then by fibroblasts, osteoblasts, osteoclasts and several bacteria. It plays a role in the physiological turnover of the periodontal ligament, root cement and alveolar bone. The amount of alkaline phosphatase in gingival crevicular fluid samples appears higher in the active sites than in the inactive sites. Moreover, elevated alkaline phosphatase levels preceded attachment loss, while no clinical parameters were yet discriminatory .
Beta-glucuronidase (host-derived enzyme)
Beta-glucuronidase is a lysosomal enzyme that could be thought as an indicator of periodontal disease activity. Lamster et al.  showed a predictive value for beta-glucuronidase in relation to clinical attachment loss. Nakashima et al.  reported that beta-glucuronidase was significantly higher in active vs. inactive sites.
Cathepsin B (host-derived enzyme)
Cathepsin B is an enzyme active in proteolysis. Macrophages are the cellular source of cathepsin B in gingival crevicular fluid . Cathepsin B levels (1) have been found to be increased in periodontitis but not in gingivitis, (2) were higher in rapid loss sites than in paired control sites and (3) appeared reduced after periodontal treatment [114–116].
MMP-8 (collagenase-2) (host-derived enzyme)
MMP-8 in gingival crevicular fluid has latent and active forms. The latent enzyme may be present in gingivitis and the active form in periodontitis. MMP-8 appears 18-fold higher in progressing periodontitis vs. stable periodontitis . Mancini et al. proposed the use of MMP-8 levels in gingival crevicular fluid as a test for active periodontal destruction .
MMP-9 (gelatinase) (host-derived enzyme)
MMP-9 appears elevated in subjects affected by advanced periodontitis associated with red complex anaerobic periodontal pathogens (e.g. P. gingivalis and T. denticola) . Samples from patients with recurrent attachment loss showed a twofold increase of mean active MMP-9, and these levels decreased significantly following adjunctive metronidazole therapy .
Dipeptidyl peptidases II and IV (host-derived enzyme)
Neutrophils, lymphocytes, macrophages and fibroblasts are the main sources of dipeptidyl peptidases II and IV. Their main function lies in the activation of the pro-forms of cytokines and enzymes and in the degradation of collagen tissue. Higher levels of both enzymes in sites with rapid and gradual attachment loss were reported with respect to sites without attachment loss .
Elastase (host-derived enzyme)
Elastase is a proteinase released from the azurophilic granules of neutrophils and from macrophages (also called MMP-12). Elastase has been recorded in GCF from periodontal patients at elevated levels and reduced after periodontal treatment. Many authors [122–124] observed higher elastase levels in sites demonstrating progressive attachment loss in comparison with inactive sites.
RANKL/OPG/RANK system (host response modifiers)
The RANKL/OPG/RANK system can be detected in the gingival tissue, GCF and saliva. In the course of periodontitis, RANKL is secreted by osteoblasts, fibroblasts, bone marrow stromal cells and activated T and B cells. Under physiological condition, RANKL produced by osteoblasts binds to RANK on the surface of pre-osteoclasts. RANKL is up-regulated by osteotropic factors such as OPG. RANKL is increased whereas OPG is decreased in periodontitis compared to healthy gingiva or gingivitis .
1-CTP (tissue breakdown products)
Pyridinoline cross-links represent a class of collagen-degrading molecules that include pyridinoline, deoxypyridinoline, N-telopeptides and C-telopeptides. The role of pyridinoline cross-linked carboxyterminal telopeptide of type I collagen (1-CTP) levels in gingival crevicular fluid as a diagnostic marker of periodontal disease activity has been investigated by several studies. High levels of 1-CTP were strongly correlated with clinical parameters and putative periodontal pathogens. Results showed that 1-CTP appeared as a good predictor of future alveolar bone and attachment loss and demonstrated significant reductions after periodontal therapy .
C-4-S (tissue breakdown products)
Chondroitin-4-sulphate (C-4-S) is the most common glycosaminoglycan in untreated chronic periodontitis sites, as shown in both animal and human studies. Elevated glycosaminoglycan concentrations were also found in aggressive periodontal diseases, and associations have been made with periodontal pathogens such as P. gingivalis. A statistically significant correlation between the GCF content of C-4-S, a bone-specific glycosaminoglycan, and PPD and CAL was reported .
Oral fluid is the mirror of periodontal health. It is a medium for clinically relevant information since it contains biomarkers specific for periodontal diseases. Although the periodontal diagnostic value of oral fluid has been recognised for some time, most scientific papers in the recent past have failed to support consistent aids to the clinician in periodontal diagnosis and therapy. Advances in microfluidics technology are revolutionising molecular biology procedures for enzymatic analysis, DNA analysis and proteomics. The evolution of microfluidics, digital microfluidics, appears promising for future application to diagnose periodontal diseases and to prognosticate periodontal treatment.
The use of LOC devices for periodontal inspection will involve less education than current diagnostic procedures and allow patients to be screened for periodontal disease in settings other than the periodontist practice, such as at general practitioners, general dentists or dental hygienists .
All these benefits make the lab-on-a-chip technology ideal for predictive, preventive, personalised and participatory periodontology. The 5Ps represents with no doubt the future of our profession. Personalised therapy with tailored respect to the particular medical reality of the specific stratified patient will be the ultimate target to be realized by the 5Ps approach. A long distance has to be covered to reach the above targets, but the pathway has already been clearly outlined: it is ‘time for new guidelines in advanced healthcare’ in dentistry too .
Written informed consent was obtained from the patients for the publication of this report and any accompanying images.
CC is a researcher and professor at the University of Naples “FEDERICO II”. SM is a full professor and the Chairman of the Degree Course in Dentistry at the University of Naples “FEDERICO II”.
The authors wish to thank the International Diabetes Federation for giving permission to reproduce Figure 19 and Prof. Dr. Christoph A. Ramseier, Department of Periodontology, University of Berne, Switzerland for giving permission to reproduce Figures 22 and 28. The authors thank Dr. Pierpaolo ‘Pirre’ Ballone for the drawings, the dental student Michele Colamaio who helped in the digital organisation of the figures and Dr. Claudia Meoli who revised the text.
- European Association for Predictive, Preventive and Personalised Medicine - EPMA. [http://www.epmanet.eu]
- Golubnitschaja O, Costigliola V, EPMA: General report & recommendations in predictive, preventive and personalised medicine 2012: white paper of the European Association for Predictive, Preventive and Personalised Medicine. EPMA J. 2012, 3: 14-PubMedPubMed CentralGoogle Scholar
- Lindhe J, Lang NP, Karring T: The anatomy of periodontal tissue. Clinical Periodontology and Implant Dentistry. Volume 1. Edited by: Lindhe J, Karring T, Araujo M. 2008, Copenhagen: Blackwell Munksgaard, 3-48. 5Google Scholar
- Armitage GC: Development of a classification system for periodontal diseases and conditions. Ann Periodontol. 1999, 4: 1-6.PubMedGoogle Scholar
- Socransky SS: Microbiology of periodontal disease – present status and future considerations. J Periodontol. 1977, 48 (9): 497-504.PubMedGoogle Scholar
- Sweeney EA, Alcoforado GA, Nyman S, Slots J: Prevalence and microbiology of localized prepubertal periodontitis. Oral Microbiol Immunol. 1987, 2 (2): 65-70.PubMedGoogle Scholar
- Bimstein E, Treasure ET, Williams SM, Dever JG: Alveolar bone loss in 5-year-old New Zealand children: its prevalence and relationship to caries prevalence, socio-economic status and ethnic origin. J Clin Periodontol. 1994, 21 (7): 447-450.PubMedGoogle Scholar
- Sjödin B, Matsson L: Marginal bone loss in the primary dentition. A survey of 7-9-year-old children in Sweden. J Clin Periodontol. 1994, 21 (5): 313-319.PubMedGoogle Scholar
- Lang N, Bartold PM, Cullinan M, Jeffcaot M, Mombelli A, Murakami S, Page R, Papapanou P, Tonetti M, Van Dyke T: Consensus report: aggressive periodontitis. Ann Periodontol. 1999, 4: 53-Google Scholar
- Tonetti MS, Mombelli A: Early-onset periodontitis. Ann Periodontol. 1999, 4 (1): 39-53.PubMedGoogle Scholar
- Lindhe J, Lang NP, Karring T: Aggressive periodontitis. Clinical Periodontology and Implant Dentistry. Volume 2. Edited by: Tonetti M, Mombelli A. 2008, Copenhagen: Blackwell Munksgaard, 429-449. 5Google Scholar
- Loevy HT: Genetic aspects of periodontal disease. Quintessence Int. 1976, 5: 1-4.Google Scholar
- Kinane DF, Hart TC: Genes and gene polymorphisms associated with periodontal disease. Crit Rev Oral Biol Med. 2003, 14: 430-449.PubMedGoogle Scholar
- Loos BG, John RP, Laine ML: Identification of genetic risk factors for periodontitis and possible mechanisms of action. J Clin Periodontol. 2005, 32 (Suppl 6): 159-179.PubMedGoogle Scholar
- Keijser BJ, Zaura E, Huse SM, van der Vossen JM, Schuren FH, Montijn RC, Ten Cate JM, Crielaard W: Pyrosequencing analysis of the oral microflora of healthy adults. J Dent Res. 2008, 87: 1016-1020.PubMedGoogle Scholar
- Socransky SS, Haffajee AD, Cugini MA, Smith C, Kent RL: Microbial complexes in subgingival plaque. J Clin Periodontol. 1998, 25: 134-144.PubMedGoogle Scholar
- Slots J, Slots H: Bacterial and viral pathogens in saliva: disease relationship and infectious risk. Periodontol 2000. 2011, 55: 48-69.PubMedGoogle Scholar
- Zambon JJ, Christersson LA, Slots J: Actinobacillus actinomycetemcomitans in human periodontal disease. Prevalence in patient groups and distribution of biotypes and serotypes within families. J Periodontol. 1983, 54: 707-711.PubMedGoogle Scholar
- Asikainen S, Chen C, Slots J: Likelihood of transmitting. Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis in families with periodontitis. Oral Microbiol Immunol. 1996, 11: 387-394.PubMedGoogle Scholar
- Altman LC, Baker C, Fleckman P, Luchtel D, Oda D: Neutrophil mediated damage to human gingival epithelial cells. J Periodontal Res. 1992, 27: 70-79.PubMedGoogle Scholar
- Weiss SJ: Tissue destruction by neutrophils. N Engl J Med. 1989, 320: 365-376.PubMedGoogle Scholar
- Dewhirst FE, Ago JM, Peros W, Stashenko P: Synergism between parathyriod hormone and interleukin-1 in stimulating bone resorption in organ culture. J Bone Miner Res. 1987, 2: 127-134.PubMedGoogle Scholar
- Beutler B, Cerami A: Cachectin and tumour necrosis factor as two sides of the same biological coin. Nature. 1986, 320: 584-588.PubMedGoogle Scholar
- Cox SW, Eley BM: Detection of cathepsin B- and L-, elastase-, tryptase-, trypsin-, and dipeptidyl peptidase IV-like activities in crevicular fluid from gingivitis and periodontitis patients with peptidyl derivatives of 7-amino-4-trifluoromethyl coumarin. J Period Res. 1989, 24: 351-353.Google Scholar
- Burgess TL, Qian Y, Kaufman S, Ring BD, Van G, Capparelli C, Kelley M, Hsu H, Boyle WJ, Dunstan CR, Hu S, Lacey DL: The ligand for osteoprotegerin (OPGL) directly activates mature osteoclasts. J Cell Biol. 1999, 145 (3): 527-538.PubMedPubMed CentralGoogle Scholar
- Yasuda H, Shima N, Nakagawa N, Mochizuki SI, Yano K, Fujise N, Sato Y, Goto M, Yamaguchi K, Kuriyama M, Kanno T, Murakami A, Tsuda E, Morinaga T, Higashio K: Identity of osteoclastogenesis inhibitory factor (OCIF) and osteoprotegerin (OPG): a mechanism by which OPG/OCIF inhibits osteoclastogenesis in vitro. Endocrinology. 1998, 139 (3): 1329-1337.PubMedGoogle Scholar
- Stabholz A, Stabholz A, Soskolne AW, Shapira L: Genetic and environmental risk factors for chronic periodontitis and aggressive periodontitis. Periodontol 2000. 2010, 53: 138-153.PubMedGoogle Scholar
- International Diabetes Federation. [http://www.idf.org/diabetesatlas/5c/ update 2012]
- Hanes PJ, Krishna R: Characteristics of inflammation common to both diabetes and periodontitis: are predictive diagnosis and targeted preventive measures possible?. EPMA J. 2010, 1: 101-116.PubMedPubMed CentralGoogle Scholar
- Tervonen T, Oliver RC: Long-term control of diabetes mellitus and periodontitis. J Clin Periodontol. 1993, 20: 431-435.PubMedGoogle Scholar
- Cianciola LJ, Park BH, Bruck E, Mosovich L, Genco RJ: Prevalence of periodontal disease in insulin-dependent diabetes mellitus (juvenile diabetes). J Am Dent Assoc. 1982, 104: 653-660.PubMedGoogle Scholar
- Löe H: Periodontal disease. The sixth complication of diabetes mellitus. Diabetes Care. 1993, 16: 329-334.PubMedGoogle Scholar
- Grossi SG, Zambon JJ, Ho AW, Koch G, Dunford RG, Machtei EE, Norderyd OM, Genco RJ: Assessment of risk for periodontal disease. I. Risk indicators for attachment loss. J Periodontol. 1994, 65: 260-267.PubMedGoogle Scholar
- Grossi SG, Genco RJ: Periodontal disease and diabetes mellitus: a two-way relationship. Ann Periodontol. 1998, 3: 51-61.PubMedGoogle Scholar
- D’aiuto F, Parkar M, Andreou G, Suvan J, Brett P, Ready D, Tonetti MS: Periodontitis and systemic inflammation: control of the local infections is associated with a reduction of serum inflammatory markers. J Dent Res. 2004, 83: 156-160.PubMedGoogle Scholar
- Iwamoto Y, Nishimura F, Nakagawa M, Sugimoto H, Shikata K, Makino H, Fukuda T, Tsuji T, Iwamoto M, Murayama Y: The effect of antimicrobial periodontal treatment on circulating tumor necrosis factor-alpha and glycated hemoglobin level in patients with type 2 diabetes. J Periodontol. 2001, 72 (6): 774-778.PubMedGoogle Scholar
- Nishimura F, Murayama Y: Periodontal inflammation and insulin resistance–lessons from obesity. J Dent Res. 2001, 80: 1690-1694.PubMedGoogle Scholar
- Promsudthi A, Pimapansri S, Deerochanawong C, Kanchanavasita W: The effect of periodontal therapy on uncontrolled type 2 diabetes mellitus in older subjects. Oral Dis. 2005, 11: 293-298.PubMedGoogle Scholar
- Aldridge JP, Lester V, Watts TL, Collins A, Viberti G, Wilson RF: Single-blind studies of the effects of improved periodontal health on metabolic control in type 1 diabetes mellitus. J Clin Periodontol. 1995, 22: 271-275.PubMedGoogle Scholar
- Christgau M, Palitzsch KD, Schmalz G, Kreiner U, Frenzel S: Healing response to non-surgical periodontal therapy in patients with diabetes mellitus: clinical, microbiological, and immunologic results. J Clin Periodontol. 1998, 25: 112-124.PubMedGoogle Scholar
- Darré L, Vergnes JN, Gourdy P, Sixou M: Efficacy of periodontal treatment on glycaemic control in diabetic patients: a meta-analysis of interventional studies. Diabetes Metab. 2008, 34: 497-506.PubMedGoogle Scholar
- Simpson TC, Needleman I, Wild SH, Moles DR, Mills EJ: Treatment of periodontal disease for glycaemic control in people with diabetes. Cochrane Database Syst Rev. 2010, 12 (5): CD004714Google Scholar
- Tonetti MS: Cigarette smoking and periodontal diseases: etiology and management of disease. Ann Periodontol. 1998, 3: 88-101.PubMedGoogle Scholar
- Calsina G, Ramon JM, Echeverria JJ: Effects of smoking on periodontal tissues. J Clin Periodontol. 2002, 29: 771-776.PubMedGoogle Scholar
- Machuca G, Rosales I, Lacalle JR, Machuca C, Bullon P: Effect of cigarette smoking on periodontal status of healthy young adults. J Periodontol. 2000, 71: 73-78.PubMedGoogle Scholar
- Palmer RM, Wilson RF, Hasan AS, Scott DA: Mechanisms of action of environmental factors – tobacco smoking. J Clin Periodontol. 2005, 32 (Suppl 6): 180-195.PubMedGoogle Scholar
- Rieder C, Joss A, Lang NP: Influence of compliance and smoking habits on the outcomes of supportive periodontal therapy (SPT) in a private practice. Oral Health Prev Dent. 2004, 2: 89-94.PubMedGoogle Scholar
- Ritchie CS: Obesity and periodontal disease. Periodontol 2000. 2007, 44: 154-163.PubMedGoogle Scholar
- Kershaw EE, Flier JS: Adipose tissue as an endocrine organ. J Clin Endocrinol Metab. 2004, 89: 2548-2556.PubMedGoogle Scholar
- Saito T, Shimazaki Y, Sakamoto M: Obesity and periodontitis. N Engl J Med. 1998, 339: 482-483.PubMedGoogle Scholar
- Al-Zahrani MS, Bissada NF, Borawskit EA: Obesity and periodontal disease in young, middle-aged, and older adults. J Periodontol. 2003, 74: 610-615.PubMedGoogle Scholar
- Linden G, Patterson C, Evans A, Kee F: Obesity and periodontitis in 60-70-year-old men. J Clin Periodontol. 2007, 34: 461-466.PubMedGoogle Scholar
- Genco RJ, Grossi SG, Ho A, Nishimura F, Murayama Y: A proposed model linking inflammation to obesity, diabetes, and periodontal infections. J Periodontol. 2005, 76: 2075-2084.PubMedGoogle Scholar
- Al-Zahrani MS, Borawski EA, Bissada NF: Increased physical activity reduces prevalence of periodontitis. J Dent. 2005, 33: 703-710.PubMedGoogle Scholar
- Al-Zahrani MS, Borawski EA, Bissada NF: Periodontitis and three health-enhancing behaviors: maintaining normal weight, engaging in recommended level of exercise, and consuming a high-quality diet. J Periodontol. 2005, 76: 1362-1366.PubMedGoogle Scholar
- Kiecolt-Glaser JK, Ricker D, George J, Messick G, Speicher CE, Garner W, Glaser R: Urinary cortisol levels, cellular immunocompetency, and loneliness in psychiatric inpatients. Psychosom Med. 1984, 46: 15-23.PubMedGoogle Scholar
- Boyapati L, Wang HL: The role of stress in periodontal disease and wound healing. Periodontol 2000. 2007, 44: 195-210.PubMedGoogle Scholar
- Peruzzo DC, Benatti BB, Ambrosano GM, Nogueira-Filho GR, Sallum EA, Casati MZ, Nociti FH: A systematic review of stress and psychological factors as possible risk factors for periodontal disease. J Periodontol. 2007, 78: 1491-1504.PubMedGoogle Scholar
- Wactawski-Wende J: Periodontal diseases and osteoporosis: association and mechanisms. Ann Periodontol. 2001, 6: 197-208.PubMedGoogle Scholar
- Von Wowern N, Klausen B, Olgaard K: Steroid-induced mandibular bone loss in relation to marginal periodontal changes. J Clin Periodontol. 1992, 19: 182-186.PubMedGoogle Scholar
- Yoshihara A, Seida Y, Hanada N, Miyazaki H: A longitudinal study of the relationship between periodontal disease and bone mineral density in community-dwelling older adults. J Clin Periodontol. 2004, 31: 680-684.PubMedGoogle Scholar
- Ramseier CA: Periodontal chart. [http://www.periodontalchart-online.com/uk/index.asp]
- Lang NP, Adler R, Joss A, Nyman S: Absence of bleeding on probing. An indicator of periodontal stability. J Clin Periodontol. 1990, 17: 714-721.PubMedGoogle Scholar
- Lang NP, Joss A, Tonetti MS: Monitoring disease during supportive periodontal treatment by bleeding on probing. Periodontol 2000. 1996, 12: 44-48.PubMedGoogle Scholar
- Joss A, Adler R, Lang NP: Bleeding on probing. A parameter for monitoring periodontal conditions in clinical practice. J Clin Periodontol. 1994, 21: 402-408.PubMedGoogle Scholar
- Lang NP, Tonetti MS: Periodontal risk assessment (PRA) for patients in supportive periodontal therapy (SPT). Oral Health Prev Dent. 2003, 1: 7-16.PubMedGoogle Scholar
- Ramseier CA: Periodontal risk assessment. [http://www.perio-tools.com/pra/en/index.asp]
- Chapple ILC: Periodontal diagnosis and treatment – where does the future lie?. Periodontol 2000. 2009, 51: 9-24.PubMedGoogle Scholar
- Point of Care Diagnostic Testing World Markets. TriMark Publications, LLC: 2012
- American Dental Association: Statement on oral fluid diagnostics. [http://www.ada.org/1890.aspx]
- Albandar JM, Brunelle JA, Kingman A: Destructive periodontal disease in adults 30 years of age and older in the United States, 1988–1994. J Periodontol. 1999, 70: 13-29.PubMedGoogle Scholar
- Ashton R, Padala C, Kane RS: Microfluidic separation of DNA. Curr Opin Biotechnol. 2003, 14: 497-504.PubMedGoogle Scholar
- Paegel BM, Blazej R, Mathies RA: Microfluidic devices for DNA sequencing: sample preparation and electrophoretic analysis. Curr Opin Biotechnol. 2003, 14: 42-50.PubMedGoogle Scholar
- Lion N, Rohner TC, Dayon L, Arnaud IL, Damoc E, Youhnovski N, Wu ZY, Roussel C, Josserand J, Jensen H, Rossier JS, Przybylski M, Girault HH: Microfluidic systems in proteomics. Electrophoresis. 2003, 24: 3533-3562.PubMedGoogle Scholar
- Huh D, Gu W, Kamotani Y, Grotberg JB, Takayama S: Microfluidics for flow cytometric analysis of cells and particles. Physiol Meas. 2005, 26: R73-R98.PubMedGoogle Scholar
- Srinivasan V, Pamula VK, Fair RB: An integrated digital microfluidic lab-on-a-chip for clinical diagnostics on human physiological fluids. Lab Chip. 2004, 4: 310-315.PubMedGoogle Scholar
- Tangerman A: Halitosis in medicine: a review. Int Dent J. 2002, 52: 201-206.PubMedGoogle Scholar
- Golberg S, Kozlovsky A, Gordon D: Cadaverine as a putative component of oral malodor. J Dent Res. 1994, 73: 1168-1172.Google Scholar
- Ratcliff PA, Johnson PW: The relationship between oral malodor, gingivitis, and periodontitis. J Periodontol. 1999, 70: 485-489.PubMedGoogle Scholar
- Rosenberg M: Clinical assessment of bad breath: current concepts. J Am Dent Assoc. 1996, 127: 475-482.PubMedGoogle Scholar
- Persson S, Edlund MB, Claesson R, Carlsson J, Persson S, Edlund MB, Claesson R, Carlsson J: The formation of hydrogen sulfide and methyl mercaptan by oral bacteria. Oral Microbiol Immunol. 1990, 5: 195-201.PubMedGoogle Scholar
- Morita M, Wang HL: Relationship of sulcular sulfide level to severity of periodontal disease and BANA test. J Periodontol. 2001, 72: 74-78.PubMedGoogle Scholar
- Rosenberg M, Leib E: Experiences of an Israeli malodor clinic. Bad Breath: Research Perspectives. Edited by: Rosenberg M. 1995, Tel Aviv: Ramot Publishing, Tel Aviv University, 137-148.Google Scholar
- Hanada M, Koda H, Onaga K, Tanaka K, Okabayashi T, Itoh T, Miyazaki H: Portable oral malodor analyzer using highly sensitive In2O3 gas sensor combined with a simple gas chromatography. Anal Chim Acta. 2003, 475: 27-35.Google Scholar
- Salako NO, Philip L: Comparison of the use of the Halimeter and the Oral Chroma™ in the assessment of the ability of common cultivable oral anaerobic bacteria to produce malodorous volatile sulfur compounds from cysteine and methionine. Med Princ Pract. 2011, 20: 75-79.PubMedGoogle Scholar
- Hatcher DC, Hatcher DC: Operational principles for cone-beam computed tomography. J Am Dent Assoc. 2010, 141: 3S-6S.PubMedGoogle Scholar
- Nikolopoulos GK, Dimou NL, Hamodrakas SJ, Bagos PG: Cytokine gene polymorphisms in periodontal disease: a meta-analysis of 53 studies including 4178 cases and 4590 controls. J Clin Periodontol. 2008, 35: 754-767.PubMedGoogle Scholar
- Kobayashi T, Yamamoto K, Sugita N, van der Pol WL, Yasuda K, Kaneko S, van de Winkel JG, Yoshie H: The Fc gamma receptor genotype as a severity factor for chronic periodontitis in Japanese patients. J Periodontol. 2001, 72: 1324-1331.PubMedGoogle Scholar
- Loos BG, De Straat FG L-V, Van de Winkel JG, Van der Velden U: Fcgamma receptor polymorphisms in relation to periodontitis. J Clin Periodontol. 2003, 30: 595-602.PubMedGoogle Scholar
- March CJ, Mosley B, Larsen A, Cerretti DP, Braedt G, Price V, Gillis S, Henney CS, Kronheim SR, Grabstein K: Cloning, sequence and expression of two distinct human interleukin-1 complementary DNAs. Nature. 1985, 315: 641-647.PubMedGoogle Scholar
- Kornman KS, Crane A, Wang HY, Di Giovine FS, Newman MG, Pirk FW, Wilson TG, Higginbottom FL, Duff GW: The interleukin-1 genotype as a severity factor in adult periodontal disease. J Clin Periodontol. 1997, 24: 72-77.PubMedGoogle Scholar
- Gore EA, Sanders JJ, Pandey JP, Palesch Y, Galbraith GM: Interleukin-1beta + 3953 allele 2: association with disease status in adult periodontitis. J Clin Periodontol. 1998, 25: 781-785.PubMedGoogle Scholar
- Taylor JJ, Preshaw PM, Donaldson PT: Cytokine gene polymorphism and immunoregulation in periodontal disease. Periodontol 2000. 2004, 35: 158-182.PubMedGoogle Scholar
- Yoshie H, Kobayashi T, Tai H, Galicia JC: The role of genetic polymorphisms in periodontitis. Periodontol 2000. 2007, 43: 102-132.PubMedGoogle Scholar
- Papapanou PN, Neiderud AM, Sandros J, Dahlén G: Interleukin-1 gene polymorphism and periodontal status. A case–control study. J Clin Periodontol. 2001, 28: 389-396.PubMedGoogle Scholar
- Cattabriga M, Rotundo R, Muzzi L, Nieri M, Verrocchi G, Cairo F, Pini PG: Retrospective evaluation of the influence of the interleukin-1 genotype on radiographic bone levels in treated periodontal patients over 10 years. J Periodontol. 2001, 72: 767-773.PubMedGoogle Scholar
- Greenstein G, Hart TC: Clinical utility of a genetic susceptibility test for severe chronic periodontitis: a critical evaluation. J Am Dent Assoc. 2002, 133: 452-459.PubMedGoogle Scholar
- Haffajee AD, Socransky SS: Microbial etiological agents of destructive periodontal diseases. Periodontol. 1994, 5: 78-111.Google Scholar
- Genco R, Kornman K, Williams R, Offenbacher S, Zambon JJ, Listgarten M, Michalowicz B, Page R, Schenkein H, Slots J, Socransky S, Van Dyke T: Consensus report periodontal diseases: pathogenesis and microbial factors. Ann Periodontol. 1996, 1: 926-932.Google Scholar
- Nørskov-Lauritsen N, Kilian M: Reclassification of Actinobacillus actinomycetemcomitans, Haemophilus aphrophilus, Haemophilus paraphrophilus and Haemophilus segnis as Aggregatibacter actinomycetemcomitans gen. nov., comb. nov., Aggregatibacter aphrophilus comb. nov. and Aggregatibacter segnis comb. nov., and emended description of Aggregatibacter aphrophilus to include V factor-dependent and V factor-independent isolates. Int J Syst Evol Microbiol. 2006, 56: 2135-2146.PubMedGoogle Scholar
- Sakamoto M, Suzuki M, Umeda M, Ishikawa I, Benno Y: Reclassification of Bacteroides forsythus as Tanerella forsythensis corrig., gen. nov., comb. nov. Int J Syst Evol Microbiol. 2002, 52: 841-849.PubMedGoogle Scholar
- Taba M, Kinney J, Kim AS, Giannobile WV: Diagnostic biomarkers for oral and periodontal diseases. Dent Clin North Am. 2005, 49: 551-571.PubMedPubMed CentralGoogle Scholar
- Lamster IB: Evaluation of components of gingival crevicular fluid as diagnostic tests. Ann Periodontol. 1997, 2: 123-137.PubMedGoogle Scholar
- Sorsa T, Tjäderhane L, Konttinen YT, Lauhio A, Salo T, Lee HM, Golub LM, Brown DL, Mäntylä P: Matrix metalloproteinases: contribution to pathogenesis, diagnosis and treatment of periodontal inflammation. Ann Med. 2006, 38: 306-321.PubMedGoogle Scholar
- Chapple ILC: Periodontal disease diagnosis: current status and future developments. J Dent. 1997, 25: 3-15.PubMedGoogle Scholar
- Chapple ILC, Matthews JB, Thorpe GH, Glenwright HD, Smith JM, Saxby MS: A new ultrasensitive chemiluminescent assay for the site-specific quantification of alkaline phosphatase in gingival crevicular fluid. J Periodontal Res. 1993, 28: 266-273.PubMedGoogle Scholar
- Denny P, Hagen FK, Hardt M, Liao L, Yan W, Arellanno M, Bassilian S, Bedi GS, Boontheung P, Cociorva D, Delahunty CM, Denny T, Dunsmore J, Faull KF, Gilligan J, Gonzalez-Begne M, Halgand F, Hall SC, Han X, Henson B, Hewel J, Hu S, Jeffrey S, Jiang J, Loo JA, Ogorzalek Loo RR, Malamud D, Melvin JE, Miroshnychenko O, Navazesh M, et al: The proteomes of human parotid and submandibular/sublingual gland salivas collected as the ductal secretions. J Proteome Res. 2008, 7: 1994-2006.PubMedPubMed CentralGoogle Scholar
- The Human Salivary Proteome Project. [http://www.skb.ucla.edu]
- Armitage GC: Analysis of gingival crevice fluid and risk of progression of periodontitis. Periodontol 2000. 2004, 34: 109-119.PubMedGoogle Scholar
- Loos BG, Tjoa S: Host-derived diagnostic markers for periodontitis: do they exist in gingival crevice fluid?. Periodontol 2000. 2005, 39: 53-72.PubMedGoogle Scholar
- Nakashima K, Giannopoulou C, Andersen E, Roehrich N, Brochut P, Dubrez B, Cimasoni G: A longitudinal study of various crevicular fluid components as markers of periodontal disease activity. J Clin Periodontol. 1996, 23: 832-838.PubMedGoogle Scholar
- Lamster IB, Holmes LG, Gross KB, Oshrain RL, Cohen DW, Rose LF, Peters LM, Pope MR: The relationship of beta-glucuronidase activity in crevicular fluid to probing attachment loss in patients with adult periodontitis. Findings from a multicenter study. J Clin Periodontol. 1995, 22: 36-44.PubMedGoogle Scholar
- Kennett CN, Cox SW, Eley BM: Investigations into the cellular contribution to host tissue proteases and inhibitors in gingival crevicular fluid. J Clin Periodontol. 1997, 24: 424-431.PubMedGoogle Scholar
- Eley BM, Cox SW: The relationship between gingival crevicular fluid cathepsin B activity and periodontal attachment loss in chronic periodontitis patients: a 2-year longitudinal study. J Periodontal Res. 1996, 31: 381-392.PubMedGoogle Scholar
- Chen HY, Cox SW, Eley BM: Cathepsin B, alpha2-macroglobulin and cystatin levels in gingival crevicular fluid from chronic periodontitis patients. J Clin Periodontol. 1998, 25: 34-41.PubMedGoogle Scholar
- Cox SW, Eley BM: Cathepsin B/L-, elastase-, tryptase-, trypsin- and dipeptidyl peptidase IV-like activities in gingival crevicular fluid. A comparison of levels before and after basic periodontal treatment of chronic periodontitis patients. J Clin Periodontol. 1992, 19: 333-339.PubMedGoogle Scholar
- Ramseier CA, Kinney JS, Herr AE, Braun T, Sugai JV, Shelburne CA, Rayburn LA, Tran HM, Singh AK, Giannobile WV: Identification of pathogen and host-response markers correlated with periodontal disease. J Periodontol. 2009, 80: 436-446.PubMedGoogle Scholar
- Mancini S, Romanelli R, Laschinger CA, Overall CM, Sodek J, McCulloch CA: Assessment of a novel screening test for neutrophil collagenase activity in the diagnosis of periodontal diseases. J Periodontol. 1999, 70: 1292-1302.PubMedGoogle Scholar
- Giannobile WV: Salivary diagnostics for periodontal diseases. J Am Dent Assoc. 2012, 143: 6S-11S.PubMedGoogle Scholar
- Teng YT, Sodek J, McCulloch CA: Gingival crevicular fluid gelatinase and its relationship to periodontal disease in human subjects. J Periodontal Res. 1992, 27: 544-552.PubMedGoogle Scholar
- Eley BM, Cox SW: Correlation between gingival crevicular fluid dipeptidyl peptidase II and IV activity and periodontal attachment loss. A 2-year longitudinal study in chronic periodontitis patients. Oral Dis. 1995, 1: 201-213.PubMedGoogle Scholar
- Jin L, Soder B, Corbet EF: Interleukin-8 and granulocyte elastase in gingival crevicular fluid in relation to periodontopathogens in untreated adult periodontitis. J Periodontol. 2000, 71: 929-939.PubMedGoogle Scholar
- Smith QT, Harriman L, Au GS, Stoltenberg JL, Osborn JB, Aeppli DM, Fischer G: Neutrophil elastase in crevicular fluid: comparison of a middle-aged general population with healthy and periodontitis groups. J Clin Periodontol. 1995, 22: 935-941.PubMedGoogle Scholar
- Palcanis KG, Larjava IK, Wells BR, Suggs KA, Landis JR, Chadwick DE, Jeffcoat MK: Elastase as an indicator of periodontal disease progression. J Periodontol. 1992, 63: 237-242.PubMedGoogle Scholar
- Belibasakis GN, Bostanci N: The RANKL-OPG system in clinical periodontology. J Clin Periodontol. 2012, 39: 239-248.PubMedGoogle Scholar
- Giannobile WV, Al- Shammari KF, Sarment DP: Matrix molecules and growth factors as indicators of periodontal disease activity. Periodontol 2000. 2003, 31: 125-134.PubMedGoogle Scholar
- Smith AJ, Addy M, Embery G: Gingival crevicular fluid glycosaminoglycan levels in patients with chronic adult periodontitis. J Clin Periodontol. 1995, 22: 355-361.PubMedGoogle Scholar
- Yager P, Edwards T, Elain F, Helton K, Nelson K, Tam MR, Weigl BH: Microfluidic diagnostic technologies for global public health. Nature. 2006, 442: 412-418.PubMedGoogle Scholar
- Giannobile WV, Beikler T, Kinney JS, Ramseier CA, Morelli T, Wong DT: Saliva as a diagnostic tool for periodontal disease: current state and future directions. Periodontol 2000. 2009, 50: 52-64.PubMedGoogle Scholar
- Christodoulides N, Floriano PN, Miller CS, Ebersole JL, Mohanty S, Dharshan P, Griffin M, Lennart A, Ballard KL, King CP, Langub MC, Kryscio RJ, Thomas MV, McDevitt JT: Lab-on-a-chip methods for point-of-care measurements of salivary biomarkers of periodontitis. Ann N Y Acad Sci. 2007, 1098: 411-428.PubMedGoogle Scholar
- Golubnitschaja O: Time for new guidelines in advanced healthcare: the mission of The EPMA Journal to promote an integrative view in predictive, preventive and personalized medicine. EPMA J. 2012, 3: 5-PubMedPubMed CentralGoogle Scholar
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.