Subgingival temperature: relation to gingival crevicular fluid enzymes, cytokines, and subgingival plaque micro-organisms

Elevated subgingival temperature infers high bacterial pathogen counts in severe periodontitis

OBJECTIVES

Periodontal inflammation may be assessed by bleeding on probing and subgingival temperature. This pilot study evaluated the intrapatient relationship between subgingival temperature and selected bacterial groups/species in deep periodontal pockets with bleeding on probing.

MATERIALS AND METHODS

In each of eight adults, an electronic temperature probe identified three "hot" pockets with elevated subgingival temperature and three "cool" pockets with normal subgingival temperature among premolars/molars with 6‒10 mm probing depths and bleeding on probing. Microbial samples collected separately from the hot and cool periodontal pockets were cultured for selected periodontal pathogens.

RESULTS

Hot compared to cool periodontal pockets revealed significantly higher absolute and normalized subgingival temperatures and yielded higher mean proportions of Porphyromonas gingivalis (10.2% for hot vs. 2.5% for cool, p = 0.030) and total red/orange complex periodontal pathogens (48.0% for hot vs. 24.6% for cool, p = 0.012).

CONCLUSIONS

Hot versus cool deep periodontal pockets harbored significantly higher levels of major periodontal pathogens. Subgingival temperature measurements may potentially be useful to assess risk of periodontitis progression and the efficacy of periodontal therapy.

In-situforming drug-delivery systems for periodontal treatment: current knowledge and perspectives

Several chemical compounds are considered to be promising as adjuvants in the treatment of periodontitis. Antimicrobials, anti-inflammatory drugs or, more recently, pro-regenerative or antioxidant molecules have shown a very interesting potential to improve the outcomes of mechanical biofilm removal and promote the healing of the damaged tissues. However, their clinical effect is often limited by the challenge of achieving effective and prolonged drug delivery within the periodontal lesion, while limiting the risk of toxicity.In-situforming implants (ISFI) are 'implantable' drug-delivery systems that have gained considerable attention over the last few decades due to their multiple biomedical applications. They are liquids that, when injected at the site to be treated, form a semi-solid or solid dosage form that provides safe and locally controlled drug release. This review discusses current data and future prospects for the use of ISFI in periodontal treatment.

Review: modulation of the oral microbiome by the host to promote ecological balance

The indivisible relationship between the human host and its oral microbiome has been shaped throughout the millennia, by facing various changes that have forced the adaptation of oral microorganisms to new environmental conditions. In this constant crosstalk between the human host and its microbiome, a bidirectional relationship has been established. The microorganisms provide the host with functions it cannot perform on its own and at the same time the host provides its microbes with a suitable environment for their growth and development. These host factors can positively affect the microbiome, promoting diversity and balance between different species, resulting in a state of symbiosis and absence of pathology. In contrast, other host factors can negatively influence the composition of the oral microbiome and drive the interaction towards a dysbiotic state, where the balance tilts towards a harmful relationship between the host and its microbiome. The aim of this review is to describe the role host factors play in cultivating and maintaining a healthy oral ecology and discuss mechanisms that can prevent its drift towards dysbiosis.

Clinical instruments and methods for assessing physical oral health: A systematic review

OBJECTIVE

This study aimed at exploring available clinical instruments and methods for assessing physical oral health, and at identifying those with sufficient diagnostic performance.

METHODS

A systematic literature search was conducted in Embase and MEDLINE. Identified instruments and methods were critically appraised, and quality of diagnostic performance was rated by two independent reviewers as A (sufficient diagnostic performance), B (either sufficient reliability or validity) or C (insufficient quality, or empirical results unsatisfactory and/or inconsistent). For all A-rated instruments and methods, an in-depth literature search was conducted to supplement and verify their effectiveness and accuracy.

RESULTS

A total of 141 instruments and methods were identified. Only 12 methods with sufficient diagnostic performance could be rated as A, 72 were rated as B, and 34 received a C-rating. Further 23 instruments and methods could not be rated due to lack of available information on diagnostic performance. Of all A-rated instruments, six were designed for tooth structure, two for periodontium, one for endodontium and three for temporomandibular joints and muscles.

CONCLUSION

Even though some instruments and methods exhibited good to excellent reliability and validity and can be recommended for research and clinical practice, they do not allow assessing all components of physical oral health. There is a need to identify and define standard instruments, and for components of physical oral health where methods with sufficient diagnostic performance are lacking, further research is required.

Myeloperoxidase level around dental implants as an indicator of an inflammatory process

Aim:

Myeloperoxidase (MPO) has been widely used as an inflammatory marker of both acute and chronic conditions. The aim of the present study was to analyze MPO found in the peri-implant sulcus fluid of implants (PISF) and gingival cervicular fluid (GCF) of natural teeth in healthy or diseased states.

Material and Methods:

A total of 107 dental implant sites, either healthy/noninflamed, inflamed or affected by periodontitis, were classified and GCF/PISF samples were obtained. GCF/PISF MPO was spectrophotometrically determined.

Results:

Both the GCF and the PISF volumes exhibited a gradual increase with gingival inflammation (P < 0.05). PISF from inflamed sites (P = 0.0001) and GCF from the gingivitis and periodontitis sites showed significantly higher total MPO levels (P < 0.05) in comparison with the noninflamed sites. The volumetric similarities of PISF and GCF in terms of response to inflammation were seen in the present study. However, some differences in PISF and GCF were observed.

Conclusion:

PISF may be suggested to have a considerable diagnostic potential as it exhibits the biologic changes around load-bearing endosseous dental implants.

Pharmacodynamics of the glucagon-like peptide-1 receptor agonist lixisenatide in Japanese and Caucasian patients with type 2 diabetes mellitus poorly controlled on sulphonylureas with/without metformin

AIMS

The PDY6797 study evaluated efficacy, safety and pharmacodynamics of lixisenatide in Japanese and Caucasian patients with type 2 diabetes mellitus (T2DM) insufficiently controlled with sulphonylureas with/without metformin.

METHODS

This randomized, double-blind, placebo-controlled trial comprised a single-dose assessment of lixisenatide 5 and 10 µg, and a 5- to 6-week repeated dose-escalation assessment of lixisenatide 5 to 30 µg once (QD) or twice daily (BID). The primary endpoint was change in postprandial plasma glucose (PPG) area under the curve (AUC)[0:29-4:30 h] after a standardized breakfast at the highest tolerated lixisenatide dose. Change from baseline in glycated haemoglobin (HbA1c), 2-h PPG and fasting plasma glucose (FPG) were assessed, as were adverse events.

RESULTS

Change from baseline in PPG AUC[0:29-4:30 h] with lixisenatide QD and BID was significantly greater than placebo (p < 0.0001 for all study populations), with particularly prominent effects in Japanese patients. Greater reductions in PPG AUC[0:29-4:30 h] were seen with lixisenatide QD versus BID, while the totality of evidence suggested that the lixisenatide 20 µg dose was optimal. In the overall population, changes from baseline for 2-h PPG, HbA1c and FPG were significant with lixisenatide QD and BID versus placebo (p < 0.01 for all). Lixisenatide was well tolerated.

CONCLUSIONS

Lixisenatide significantly reduced PPG AUC[0:29-4:30 h] versus placebo at the highest well-tolerated dose in patients with T2DM treated with sulphonylureas with/without metformin and had a good safety and tolerability profile. Japanese patients experienced particular benefits with lixisenatide in terms of reductions in PPG excursions.

Expression of interferon-γ, interferon-α and related genes in individuals with Down syndrome and periodontitis

BACKGROUND

Recently, attenuation of anti-inflammatory and increase of pro-inflammatory mediators was demonstrated in individuals with Down syndrome (DS) in comparison with euploid patients during periodontal disease (PD), suggesting a shift to a more aggressive inflammation in DS.

AIM

To determine the influence of DS in the modulation of interferons (IFNs) signaling pathway in PD.

MATERIALS AND METHODS

Clinical periodontal assessment was performed and gingival tissue samples obtained from a total of 51 subjects, including 19 DS individuals with PD, 20 euploid individuals with PD and 12 euploid individuals without PD. Expression levels of interferon-gamma (IFNG) and interferon-alpha (IFNA), and their receptors IFNGR1, IFNGR2, IFNAR1 and IFNAR2, the signaling intermediates Janus kinase 1 (JAK1), signal transducer and activator of transcription 1 (STAT1) and interferon regulatory factor 1 (IRF1) were determined using real time quantitative polymerase chain reaction (qPCR).

RESULTS

Clinical signs of periodontal disease were markedly more severe in DS and euploid patients with PD in comparison to euploid and periodontally healthy patients. There was no difference on mRNA levels of IFNA, IFNG, INFGR2, IFNAR1 and IFNAR2 between DS and euploid individuals, even though some of these genes are located on chromosome 21. STAT1 and IRF1 mRNA levels were significantly lower in DS patients in comparison with euploid individuals with PD. In euploid individuals, PD was associated with an increased expression of IFNGR1, IFNGR2, IFNAR1, STAT1 and IRF1.

CONCLUSIONS

Reduced expression of STAT1 and IRF1 genes indicate an impaired activation of IFNs signaling in individuals with DS and PD. Expression of IFNA, IFNG and IFN receptors was not altered in DS patients, indicating that indirect mechanisms are involved in the reduced activation of IFN signaling.

What do 'omic technologies have to offer periodontal clinical practice in the future?

BACKGROUND AND OBJECTIVE

Periodontal diseases are the most common chronic inflammatory diseases of humans and a major cause of tooth loss. Inflammatory periodontitis is also a complex multifactorial disease involving many cell types, cell products and interactions. It is associated with a dysregulated inflammatory response, which fails to resolve, and which also fails to re-establish a beneficial periodontal microbiota. There is a rich history of biomarker research within the field of periodontology, but exemplary improvements in analytical platform technologies offer exciting opportunities for discovery. These include the 'omic technologies, such as genomics, transcriptomics, proteomics and metabolomics, which provide information on global scales that can match the complexity of the disease. This narrative review focuses on the recent advances made in in vivo human periodontal research by use of 'omic technologies.

MATERIAL AND METHODS

The Medline database was searched to identify articles currently available on 'omic technologies with regard to periodontal research.

RESULTS

One hundred and sixty-one articles focusing on biomarkers of and 'omic advances in periodontal research were analysed for their contributions to the understanding of periodontal diseases.

CONCLUSION

The data generated by the use of 'omic technologies have huge potential to inform paradigm shifts in our understanding of periodontal diseases, but data management, analysis and interpretation require a thoughtful and systematic bioinformatics approach, to ensure meaningful conclusions can be made.

Comparison of gingival crevicular fluid sampling methods in patients with severe chronic periodontitis

BACKGROUND

The analysis of samplings from periodontal pockets is important in the diagnosis and therapy of periodontitis. In this study, three different sampling techniques were compared to determine whether one method yielded samples suitable for the reproducible and simultaneous determination of bacterial load, cytokines, neutrophil elastase, and arginine-specific gingipains (Rgps). Rgps are an important virulence factor of Porphyromonas gingivalis, the exact concentration of which in gingival crevicular fluid (GCF) has not been quantified.

METHODS

GCF was sampled from four sites per patient (one sample per quadrant using two samples per method) in 36 patients with chronic periodontitis. One week later, the procedure was repeated with alternative methods. Variables determined were loads of Aggregatibacter actinomycetemcomitans (previously Actinobacillus actinomycetemcomitans) and P. gingivalis, levels of interleukin-6 and -8, activity of neutrophil elastase, and level of Rgps.

RESULTS

The detected cytokine levels were higher using paper strips compared to paper points. Bacteria were found in similar loads from paper strips and paper points. Rgps were only detectable in high quantities by washing the periodontal pocket. The level of Rgps correlated with the load of P. gingivalis.

CONCLUSIONS

The use of paper strips was suitable for the simultaneous determination of microbial and immunologic parameters. Obtaining GCF by washing can be useful for special purposes. The gingipain concentration in periodontal pockets was directly determined to be ≤1.5 μM. This value indicated that most of the substrates of these proteases by in vitro assays identified until now can be easily degraded in P. gingivalis-infected sites.

Myeloperoxidase content is a marker of systemic inflammation in a chronic condition: the example given by the periodontal disease in rats

The study aimed to evaluate the suitability of myeloperoxidase (MPO) content as a local indicator of chronic inflammation, using the periodontal disease model. Anesthetized adult male Holtzman rats had their second left maxilar molar tied by a thread for 11 days and were then killed. Blood samples and photographic images from histopathological inflamed and noninflamed (contralateral) neighboring gingivomucosal specimens were collected for cell counts and MPO level analysis. Diseased animals were also treated with pharmacological tools such as the anti-inflammatory drug celecoxib or the opioid morphine. Increased blood neutrophils and local cell numbers characterized diseased animals. However, local MPO content was increased in inflamed and noninflamed tissues from diseased animals. Celecoxib and morphine reduced blood neutrophils and bilateral MPO content, but only celecoxib reduced local cell numbers in diseased animals. It is concluded that MPO content is a good indicator of a systemic rather than a local inflammation in a chronic inflammatory condition.

Significance of thrombomodulin release from gingival epithelial cells in periodontitis patients

BACKGROUND AND OBJECTIVE

Thrombomodulin, a cell transmembrane glycoprotein, binds to thrombin and converts it from a procoagulant protease to an anticoagulant enzyme that activates protein C. Thrombomodulin is very important in regulating the function of thrombin. Elevated soluble thrombomodulin is present in the gingival crevicular fluid of subjects with periodontitis. The objective of the present study was to investigate the mechanisms about the elevated soluble thrombomodulin in gingival crevicular fluid.

MATERIAL AND METHODS

Gingival sections from six patients with chronic periodontitis and from three periodontally healthy subjects were immunostained for thrombomodulin detection. Thrombomodulin levels were investigated in the gingival crevicular fluid of 11 subjects with chronic periodontitis. The effects of neutrophil enzymes on thrombomodulin release and on thrombomodulin in the gingival crevicular fluid were examined by an enzyme-linked immunosorbent assay or by Western blotting.

RESULTS

The expression of gingival epithelial thrombomodulin was lost or decrease near infiltrating neutrophils. Thrombomodulin was rapidly released from gingival epithelial cells by neutrophil enzymes, and gingival crevicular fluid with periodontitis included the proteolytic cleavage thrombomodulin using immunoblotting analysis. The thrombomodulin release was not caused by rapid cell damage, on lactate dehydrogenase assay. There were significant differences in thrombomodulin content between gingival crevicular fluid samples from healthy and diseased sites, regardless of the degree of probing depth.

CONCLUSION

Neutrophil enzymes induced rapid thrombomodulin release from the membrane surface of gingival epithelial cells. This might explain the thrombomodulin increase in gingival crevicular fluid with local diseased gingiva. Elevation of thrombomodulin in gingival crevicular fluid may be a potential marker of epithelial cell membrane injury.

HtrA in Porphyromonas gingivalis can regulate growth and gingipain activity under stressful environmental conditions

In several micro-organisms, HtrA, a serine periplasmic protease, is considered an important virulence factor that plays a regulatory role in oxidative and temperature stress. The authors have previously shown that the vimA gene product is an important virulence regulator in Porphyromonas gingivalis. Further, purified recombinant VimA physically interacted with the major gingipains and the HtrA from P. gingivalis. To further evaluate a role for HtrA in the pathogenicity of this organism, a 1.5 kb fragment containing the htrA gene was PCR-amplified from the chromosomal DNA of P. gingivalis W83. This gene was insertionally inactivated using the ermF-ermAM antibiotic-resistance cassette and used to create an htrA-deficient mutant by allelic exchange. In one randomly chosen isogenic mutant designated P. gingivalis FLL203, there was increased sensitivity to hydrogen peroxide. Growth of this mutant at an elevated temperature was more inhibited compared to the wild-type. Further, in contrast to the wild-type, there was a significant decrease in Arg-gingipain activity after heat shock in FLL203. However, the gingipain activity in the mutant returned to normal levels after a further 30 min incubation at room temperature. Collectively, these data suggest that HtrA may play a similar role in oxidative and temperature stress in P. gingivalis as observed in other organisms.

The effects of a tea tree oil-containing gel on plaque and chronic gingivitis

BACKGROUND

[corrected] This clinical study assessed the effects of topically applied tea tree oil (TTO)-containing gel on dental plaque and chronic gingivitis.

METHODS

This was a double-blind, longitudinal, non-crossover study in 49 medically fit non-smokers (24 males and 25 females) aged 18-60 years with severe chronic gingivitis. Subjects were randomly assigned to three groups and given either TTO-gel (2.5 per cent), chlorhexidine (CHX) gel (0.2 per cent), or a placebo gel to apply with a toothbrush twice daily. Treatment effects were assessed using the Gingival Index (GI), Papillary Bleeding Index (PBI) and plaque staining score (PSS) at four and eight weeks.

RESULTS

No adverse reactions to any of the gels were reported. The data were separated into subsets by tooth (anterior and posterior) and tooth surface (buccal and lingual). The TTO group had significant reduction in PBI and GI scores. However,,TTO did not reduce plaque scores, which tended to increase over the latter weeks of the study period.

CONCLUSION

Although further studies are required, the anti-inflammatory properties of TTO-containing gel applied topically to inflamed gingival tissues may prove to be a useful non-toxic adjunct to chemotherapeutic periodontal therapy.

Neutrophil serine proteinases activate human nonepithelial cells to produce inflammatory cytokines through protease-activated receptor 2

Protease-activated receptors (PARs) compose a family of G protein-coupled receptors activated by proteolysis with exposure of their tethered ligand. Recently, we reported that a neutrophil-derived serine proteinase, proteinase 3 (PR3), activated human oral epithelial cells through PAR-2. The present study examined whether other neutrophil serine proteinases, human leukocyte elastase (HLE), and cathepsin G (Cat G) activate nonepithelial cells, human gingival fibroblasts (HGF). HLE and Cat G as well as PR3 activated HGF to produce IL-8 and monocyte chemoattractant protein 1. Human oral epithelial cells but not HGF express mRNA and protein of secretory leukocyte protease inhibitor, an inhibitor of HLE and Cat G, and recombinant secretory leukocyte protease inhibitor clearly inhibited the activation of HGF induced by HLE and Cat G but not by PR3. HGF express PAR-1 and PAR-2 mRNA in the cells and the proteins on the cell surface. HLE and Cat G cleaved the peptide corresponding to the N terminus of PAR-2 with exposure of its tethered ligand. Treatment with trypsin, an agonist for PAR-2, and a synthetic PAR-2 agonist peptide induced intracellular Ca(2+) mobilization and rendered cells refractory to subsequent stimulation with HLE and Cat G. The production of cytokine induced by HLE and Cat G and the PAR-2 agonist peptide was completely abolished by inhibition of phospholipase C. These findings suggest that neutrophil serine proteinases have equal ability to activate human nonepithelial cells through PAR-2 to produce inflammatory cytokines and may control a number of inflammatory processes such as periodontitis.

Quantification of gingival edema using a new 3-D laser scanning method

OBJECTIVES

The aim of the study was to investigate the suitability of measuring volume differences in the gingival tissue for monitoring changes in the inflammatory status of the gingiva.

MATERIALS AND METHODS

Data for this investigation were obtained from a mouthrinse evaluation which was performed as a 4-week, double-blind, placebo-controlled, cross-over study in which localised experimental gingivitis was induced. 24 volunteers were enrolled in the study. Only the data from the placebo period of each subject were used in the current investigation. During the plaque accumulation periods, plaque guards were worn during routine performance of oral hygiene measures to prevent any plaque removal from the experimental area (1st and 2nd premolars and molars in one upper quadrant). Clinical examinations with assessment of plaque and gingivitis were performed on days 0, 4, 7, 14, 21, 28 and 42. Volume differences in the gingival papillae were determined between day 0 and days 21, 28, and 42, and between days 28 and 42 by taking measurements from replicas of the respective clinical situations using a 3-D laser scanner and reference-free automated 3-D superimposition software. Data were analysed with the Wilcoxon signed ranks test.

RESULTS

Plaque accumulation in the experimental area resulted in a highly significant increase (p<0.001) of inflammation of the gingival papillae. The mean (standard deviation) papillary GI at baseline was 0.23 (0.34) as compared to 1.22 (0.27) and 1.2 (0.31) on days 21 and 28, respectively. The mean increase in volume of all papillae as compared to baseline was 25,478 micrometer3 after 21 days and 24,210 micrometer3 after 28 days. After resuming a normal oral hygiene regimen, mean volume of the papillae decreased between days 28 and 42 by 19,250 micrometer3.

CONCLUSION

With this novel method, gingival papillary edema can be quantified in vivo from replicas of the clinical situation.

Identification and consequences of distinct Löe-Silness gingival index examiner styles for the clinical assessment of gingivitis

BACKGROUND

In clinical studies, gingivitis is most frequently assessed by the Löe-Silness gingival index (GI). The objective of this work was to develop an understanding of how clinicians experienced with GI differ with respect to how they apply GI and to assess the impact of different examination styles on statistical outcomes and magnitude of treatment differences.

METHODS

A method was developed to mathematically relate the average GI score and degree of bleeding observed for a subject. Graphical analyses were used to profile examiner styles with respect to using the GI index. A prospective single-center, examiner-blind study comparing the effects of a staggered prophylaxis on gingivitis was then conducted, where a difference in gingivitis was created between two balanced groups by providing subjects a prophylaxis at two staggered time points. Subjects were assigned to one of two cohorts; within each cohort, group 1 subjects received a dental prophylaxis following the baseline examination and group 2 subjects received a dental prophylaxis 8 weeks later. Five to 7 days after the group 2 prophylaxis, all subjects were examined for GI. Twelve experienced clinicians participated.

RESULTS

Retrospective analyses indicated the presence of distinct examiner styles which are based on the frequency that a given GI score (0, 1, 2, or 3) is measured by a clinician. In the prospective study, all 12 examiners observed statistically significant differences between the prophylaxis treatment groups at the final visit for both mean number of bleeding sites and mean GI; the magnitude ranged from 21.5% to 84.6% for mean number of bleeding sites and 9.4% to 39.2% for mean GI. There were 4 distinct styles employed by these experienced clinicians.

CONCLUSIONS

Varying examiner styles impact the structure of resulting data. Importantly, the implementation of arbitrary thresholds (e.g., 20%) regarding percent treatment differences between groups as a guideline for judging the clinical significance is scientifically unsupported. A more scientific criterion in the field of gingivitis clinical testing would be the independent demonstration of statistical superiority compared to a negative control and/or a demonstration of similar or superior efficacy to clinically proven positive controls. In addition, interexaminer calibration is a mechanism that can be utilized to minimize the impact of different examiner styles in clinical settings involving more than one examiner.

Microassay for the detection of elastase activity in the gingival crevice

BACKGROUND, AIMS

A new microassay for the detection of elastase activity (EA) in gingival crevicular fluid (GCF) has been established. GCF was collected with Periopaper strips and quantified in a Periotron.

METHODS

Enzyme activity was measured in a microtiter plate reader, using a fluorometric assay. To ensure quality and precision of the assay, recovery rates were determined at different activities with a recovery of >90%. In a 2nd step, stability of the enzyme was investigated during storage at room temperature, +4 degrees C, -22 degrees C, -88 degrees C. GCF samples retained elastase activity of almost 100% after a storage of 3 days at -22 degrees C. In a group of 12 healthy volunteers, elastase activity was assayed throughout an 18 day experimental gingivitis protocol.

RESULTS

Median activity increased from 481 microU/microl at baseline to 1444 microU/microl at day 18, which was accompanied by the development of the signs of gingivitis. The increase of EA during the experimental phase of the study was highly significant (p<0.001) and correlated well with the increasing severity of gingivitis.

CONCLUSION

The data suggest that elastase activity in GCF is an excellent quantitative measure of gingival inflammation.

Dental plaque-induced gingival diseases

Gingival diseases are a diverse family of complex and distinct pathological entities found within the gingiva that are the result of a variety of etiologies. There are several clinical characteristics common to all gingival diseases and these features include clinical signs of inflammation, signs and symptoms that are confined to the gingiva, reversibility of the disease by removing the etiology, the presence of bacterial laden plaque to initiate and/or exacerbate the severity of the disease and a possible role as a precursor for attachment loss around teeth. Defining and classifying gingival diseases has not been an easy task. The tools and methods to identify gingival diseases have varied depending on the criteria used by epidemiologists, researchers, or the practicing clinician. The classification of gingival disease in this review relied upon experimental and/or epidemiological human studies that accurately and reliably assessed an underlying functional derangement that was localized to the gingiva and was reported in a peer-reviewed journal. The classification of gingival diseases that depends on dental plaque to initiate the disease process(es) has been categorized into two groups. The two categories of plaque-induced gingival diseases are those affected by local factors and those that are affected by local factors and modified by specific systemic factors found in the host. In this review, the clinical characteristics of gingival disease associated with plaque, endogenous hormone fluctuations, drugs, systemic diseases, and malnutrition were investigated.

Protein recovery from several paper types used to collect gingival crevicular fluid

The purpose of this study was to compare the efficiency of protein elution from several types of gingival crevicular fluid (GCF) collection papers when the volume of the inoculated protein and the elution methods were constant. Various concentrations of bovine serum albumin (BSA) and 14C-BSA were placed onto strips of Whatman #1 [W1], Whatman 3 MM chromatographic [W3], Periopaper (ProFlow) [P] and Periopaper (Harco) [H], and recovered proteins measured following a non-optimized centrifugal elution technique. There were significant differences in % recovery of BSA and 14C-BSA from the papers, which was dependent on both the type of paper and the concentration of the inoculated protein; that is, proteins at the lowest concentrations were less efficiently eluted from GCF collection papers than those at higher concentrations. Equations for regression lines of elution efficiency were quadratic. Thus, our data suggest significant differences in the efficiency for elution of BSA from absorbent papers when the volume of the inoculated fluid and the elution technique were constant. Previous variable or conflicting experimental data between research groups may have resulted from incomplete elution of proteins from GCF collection papers, possibly due to entrapment within, or binding of GCF proteins to the paper.