Antibiotic resistance in the microbiota of periodontitis patients: an update of current findings.

Systemic antibiotics are an effective adjunct in the treatment of periodontitis, but their judicious use is necessary as antimicrobial resistance is a growing global concern. This review aims to explore the current understanding and insight related to antibiotic resistance in the subgingival microbiota of periodontitis patients. A search of MEDLINE (PubMed) was carried out from 1 January 2012 to 25 November 2021 for studies related to antibiotic resistance in periodontitis patients. Of the 90 articles identified, 12 studies were selected for inclusion. A significant incidence of antibiotic resistant isolates was reported for Porphyromonas gingivalis, Prevotella intermedia, Prevotella denticola, Prevotella melaninogenica, Fusobacterium nucleatum, Tanerella forsythia, Aggretibacter actinomycetemcomitans, Streptococcus constellatus, Streptococcus intermedius, and Parvimonas micra, but resistance to specific antibiotics did not reach above 10% of isolates in most studies except for amoxicillin resistance in Aggretibacter actinomycetemcomitans. The highest frequency of resistance across all bacterial species was for amoxicillin, clindamycin, and metronidazole. However, resistance patterns were widely variable across geographical locations, and the high heterogeneity between antibiotic-resistant isolates across studies precludes any clinical recommendations from this study. Although antibiotic resistance has yet to reach critical levels in periodontitis patients, an emphasis on antibiotic stewardship interventions such as point-of-care diagnostics and education for key stakeholders is needed to curb a growing problem.

The diagnostic power of salivary electrolytes for Sjögren's disease: a systematic literature review and meta-analysis.

OBJECTIVES: To perform a systematic review and meta-analysis to determine the power of salivary electrolytes for the diagnosis of Sjögren's disease (SjD). METHODS: A literature search was conducted (last search March 2023) using PubMed and Web of Science and completed with a manual search. Articles were screened for reports of human salivary ion concentrations, comparing SjD patients with healthy controls and/or sicca patients. Articles not using the SjD classification criteria or performing the classification as part of the experimental design were excluded. Forest plots were used to present the meta-analyses results for each ion, distinguishing between salivary type (unstimulated and stimulated whole saliva, submandibular/sublingual and parotid saliva). RESULTS: A total of 21 out of 722 articles were eligible for inclusion. For SjD patients a significant increase in salivary ion concentration was observed for sodium, chloride and calcium when comparing to healthy controls. Significant differences between SjD and sicca patients were noted for sodium, chloride, phosphate, calcium, phosphate, nitrite and nitrate. Stimulated whole saliva showed larger variability in results between studies in comparison to other types of saliva (unstimulated whole saliva, submandibular/sublingual saliva and parotid saliva). CONCLUSIONS: Despite differences in saliva type, salivary ion levels could be utilised for the screening for SjD. Making use of chloride in combination with sodium would be most promising for distinguishing SjD patients from healthy controls and adding phosphate to potentially make a distinguishment with sicca patients. Unstimulated whole saliva should be the first choice when testing salivary ion concentrations.

Current and Potential Applications of Monoterpenes and Their Derivatives in Oral Health Care.

Plant products have been employed in medicine for centuries. As the world becomes more health-conscious, there is a growing interest in natural and minimally processed products for oral health care. This has led to an increase in research into the bioactive compounds found in plant products, particularly monoterpenes. Monoterpenes are known to have beneficial biological properties, but the specific mechanisms by which they exert their effects are not yet fully understood. Despite this, some monoterpenes are already being used in oral health care. For example, thymol, which has antibacterial properties, is an ingredient in varnish used for caries prevention. In addition to this, monoterpenes have also demonstrated antifungal, antiviral, and anti-inflammatory properties, making them versatile for various applications. As research continues, there is potential for even more discoveries regarding the benefits of monoterpenes in oral health care. This narrative literature review gives an overview of the biological properties and current and potential applications of selected monoterpenes and their derivatives in oral health care. These compounds demonstrate promising potential for future medical development, and their applications in future research are expected to expand.

Comparing SARS-CoV-2 Viral Load in Human Saliva to Oropharyngeal Swabs, Nasopharyngeal Swabs, and Sputum: A Systematic Review and Meta-Analysis.

A systematic review and meta-analysis were conducted to investigate the SARS-CoV-2 viral load in human saliva and compared it with the loads in oropharyngeal swabs, nasopharyngeal swabs, and sputum. In addition, the salivary viral loads of symptomatic and asymptomatic COVID-19 patients were compared. Searches were conducted using four electronic databases: PubMed, Embase, Scopus, and Web of Science, for studies published on SARS-CoV-2 loads expressed by CT values or copies/mL RNA. Three reviewers evaluated the included studies to confirm eligibility and assessed the risk of bias. A total of 37 studies were included. Mean CT values in saliva ranged from 21.5 to 39.6 and mean copies/mL RNA ranged from 1.91 × 101 to 6.98 × 1011. Meta-analysis revealed no significant differences in SARS-CoV-2 load in saliva compared to oropharyngeal swabs, nasopharyngeal swabs, and sputum. In addition, no significant differences were observed in the salivary viral load of symptomatic and asymptomatic COVID-19 patients. We conclude that saliva specimen can be used as an alternative for SARS-CoV-2 detection in oropharyngeal swabs, nasopharyngeal swabs, and sputum.

Non-surgical peri-implantitis treatment with or without systemic antibiotics: a randomized controlled clinical trial.

OBJECTIVES: To assess the adjunctive effect of systemic amoxicillin (AMX) and metronidazole (MTZ) in patients receiving non-surgical treatment (NST) for peri-implantitis (PI). MATERIALS AND METHODS: Thirty-seven patients were randomized into an experimental group treated with NST plus AMX + MTZ (N = 18) and a control group treated with NST alone (N = 19). Clinical parameters were evaluated at 12 weeks post-treatment. The primary outcome was the change in peri-implant pocket depth (PIPD) from baseline to 12 weeks, while secondary outcomes included bleeding on probing (BoP), suppuration on probing (SoP), and plaque. Data analysis was performed at patient level (one target site per patient). RESULTS: All 37 patients completed the study. Both groups showed a significant PIPD reduction after NST. The antibiotics group showed a higher mean reduction in PIPD at 12 weeks, compared with the control group (2.28 ± 1.49 mm vs. 1.47 ± 1.95 mm), however, this difference did not reach statistical significance. There was no significant effect of various potential confounders on PIPD reduction. Neither treatment resulted in significant improvements in BoP at follow-up; 30 of 37 (81%) target sites still had BoP after treatment. Only two implants, one in each group, exhibited a successful outcome defined as PIPD < 5 mm, and absence of BoP and SoP. CONCLUSIONS: Non-surgical treatment was able to reduce PIPD at implants with PI. The adjunctive use of systemic AMX and MTZ did not show statistically significant better results compared to NST alone. NST with or without antibiotics was ineffective to completely resolve inflammation around dental implants.

Role of the oral microbiome, metabolic pathways, and novel diagnostic tools in intra-oral halitosis: a comprehensive update.

Halitosis or oral malodor is one of the most common reasons for the patients' visit to the dental clinic, ranking behind only dental caries and periodontitis. In the present times, where social and professional communications are becoming unavoidable, halitosis has become a concern of growing importance. Oral malodor mostly develops due to the putrefaction of substrates by the indigenous bacterial populations. Although culture-based studies have provided adequate information on halitosis, the high throughput omics technologies have amplified the resolution at which oral microbial community can be examined and has led to the detection of a broader range of taxa associated with intra-oral halitosis (IOH). These microorganisms are regulated by the interactions of their ecological processes. Thus to develop effective treatment strategies, it is important to understand the microbial basis of halitosis. In the current review, we provide an update on IOH in context to the role of the oral microbiome, metabolic pathways involved, and novel diagnostic tools, including breathomics. Understanding oral microbiota associated with halitosis from a broader ecological perspective can provide novel insights into one's oral and systemic health. Such information can pave the way for the emergence of diagnostic tools that can revolutionize the early detection of halitosis and various associated medical conditions.

Submucosal microbiome of peri-implant sites: A cross-sectional study.

AIM: To study the peri-implant submucosal microbiome in relation to implant disease status, dentition status, smoking habit, gender, implant location, implant system, time of functional loading, probing pocket depth (PPD), and presence of bleeding on probing. MATERIALS AND METHODS: Biofilm samples were collected from the deepest peri-implant site of 41 patients with paper points, and analysed using 16S rRNA gene pyrosequencing. RESULTS: We observed differences in microbial profiles by PPD, implant disease status, and dentition status. Microbiota in deep pockets included higher proportions of the genera Fusobacterium, Prevotella, and Anaeroglobus compared with shallow pockets that harboured more Rothia, Neisseria, Haemophilus, and Streptococcus. Peri-implantitis (PI) sites were dominated by Fusobacterium and Treponema compared with healthy implants and peri-implant mucositis, which were mostly colonized by Rothia and Streptococcus. Partially edentulous (PE) individuals presented more Fusobacterium, Prevotella, and Rothia, whereas fully edentulous individuals presented more Veillonella and Streptococcus. CONCLUSIONS: PPD, implant disease status, and dentition status may affect the submucosal ecology leading to variation in composition of the microbiome. Deep pockets, PI, and PE individuals were dominated by Gram-negative anaerobic taxa.

Comparing periodontitis biomarkers in saliva, oral rinse and gingival crevicular fluid: A pilot study.

AIM: To explore the feasibility of screening for periodontitis by measuring biomarkers, namely total proteolytic activity (TPA), matrix metalloproteinase (MMP)-8, chitinase, lysozyme or their combination, in saliva, oral rinse and gingival crevicular fluid (GCF). MATERIAL AND METHODS: Subjects were recruited among healthy/gingivitis individuals and untreated periodontitis patients in Academic Centre for Dentistry Amsterdam (ACTA). All participants donated samples of unstimulated whole saliva, oral rinse and GCF. The protein concentrations and MMP-8 levels were determined by ELISA. Enzymatic activities were measured using appropriate fluorogenic substrates. RESULTS: In oral rinse samples, periodontitis patients (n = 19) exhibited significantly higher concentrations of MMP-8 and TPA than controls (n = 20). MMP-8 in combination with chitinase explained 88% of the variance and assigned a subject to control or periodontitis group, with best accuracy (87.2%) in oral rinse. CONCLUSIONS: The combination of MMP-8 and chitinase in the current oral rinse procedure has the potential to discriminate periodontitis from periodontal health/gingivitis.

Adjunctive effect of mouthrinse on treatment of peri-implant mucositis using mechanical debridement: A randomized clinical trial.

AIM: To study effect of delmopinol hydrochloride (DEL) in comparison with chlorhexidine digluconate (CHX) and a placebo (PLA) in addition to non-surgical mechanical debridement in patients with peri-implant mucositis. MATERIALS AND METHODS: Eighty-nine patients with at least one implant diagnosed with peri-implant mucositis were randomly assigned to one of three study groups (DEL, CHX and PLA). Professional non-surgical mechanical debridement was performed at baseline. Mouth rinsing was carried out by the patients twice a day in addition to their regular oral hygiene practices. Assessments of efficacy were performed for the primary outcome - Implant bleeding on probing (IBOP%) and secondary outcomes - modified Bleeding Index (mBI) and modified Plaque Index (mPI) at 1 and 3 months. RESULTS: At 3 months, there was statistically significant reduction in IBOP% and mBI within the study groups compared to baseline. However, there was no statistically significant difference between the study groups at 3 months follow-up. Moreover, there was a statistically significant difference according to mPI at 1 month between the chlorhexidine and placebo group (p = .004). CONCLUSIONS: This study confirms that mechanical debridement combined with oral hygiene instruction is effective in treatment of peri-implant mucositis. The clinical effects between groups were comparable.

Three periodontitis phenotypes: Bone loss patterns, antibiotic-surgical treatment and the new classification.

AIM: To compare three periodontitis clusters (A, B and C) for alveolar bone loss (ABL) patterns, antibiotic prescriptions and surgeries and to relate them to the new classification of periodontitis. MATERIALS AND METHODS: ABL patterns, prescription of systemic antibiotics and the number of surgeries were retrieved for all patients (n = 353) in the clusters. Comparisons and possible predictors for antibiotics were assessed, and results also evaluated in relation to the new classification. RESULTS: Cluster A is characterized by angular defects often affecting the first molars and localized stage III/IV grade C periodontitis. Cluster B contains mainly localized or generalized stage III/IV, grade C patients. Cluster C contains mainly patients with generalized stage III/IV grade C periodontitis. Patients in cluster A received significantly more antibiotics compared to B and C (78% vs. 23% and 17%); the predictors for antibiotic prescription were young age and localized ABL. No differences in numbers of periodontal surgeries were observed between clusters (A = 1.0 ± 1.4, B = 1.3 ± 1.4 and C = 1.3 ± 1.5). CONCLUSIONS: Within stage III/IV grade C periodontitis, we could detect three clusters of patients. The distinct localized ABL pattern and younger age in cluster A presumably prompted clinicians to prescribe antibiotics.

Surgical treatment of peri-implantitis defects with two different xenograft granules: A randomized clinical pilot study.

OBJECTIVES: To investigate whether xenograft EB (EndoBon) is non-inferior to xenograft BO (Bio-Oss) when used in reconstructive surgery of peri-implant osseous defects. MATERIALS AND METHODS: Dental patients with one implant each demonstrating peri-implantitis were randomized to receive surgical debridement and defect fill with either BO or EB. Changes in bone level (BL) and intrabony defect depth (IDD) evaluated radiographically were the primary outcomes. The secondary outcomes included changes in probing pocket depth (PPD), bleeding on probing (BoP), and suppuration on probing (SoP). All outcomes were recorded before treatment and at 6 and 12 months post-treatment. RESULTS: Twenty-four patients (n = 11 BO, n = 13 EB) completed the study. Both groups demonstrated significant within-group improvements in all clinical and radiographic parameters at 6 and 12 months (p ≤ .001). At 12 months, both groups presented with IDD reductions of 2.5-3.0 mm on average. The inter-group differences were not statistically significant at all time points and for all the examined parameters (p > .05). While the radiographic defect fill in both groups exceeded > 1 mm and can be considered treatment success, successful treatment outcomes as defined by Consensus Reporting (no further bone loss, PPD ≤ 5 mm, no BOP, and no SoP) were identified in 2/11 (18%) BO and 0/13 (0%) EB individuals (Fisher's exact test, p = .199). CONCLUSIONS: Within the limitations of this pilot study, the application of xenograft EB showed to be non-inferior to xenograft BO when used in reconstructive surgery of peri-implant osseous defects.

Qualitative and quantitative differences in the subgingival microbiome of the restored and unrestored teeth.

BACKGROUND AND OBJECTIVE: Metal-based dental restorations with a subgingival outline may enhance plaque accumulation and bacterial colonization. This study aimed to investigate whether metal-based restorations influence the composition of subgingival microbiome. MATERIAL AND METHODS: Per subject one site with a metal-based restoration and one contra-lateral site without a restoration were selected on basis of radiographic bone loss ≤2 mm, restoration outline at sulcus level/subgingivally, pocket depth ≤4 mm, and no root canal treatments. Subgingival samples were collected with sterile paper-points, and microbial profiles were obtained by 16S rRNA gene amplicon sequencing. Restorations were sampled with an Arkansas-stone and the metal composition was determined using energy-dispersive X-ray spectroscopy. RESULTS: A total of 22 sites from 11 subjects were included. No significant differences for the clinical parameters were found between the restored and unrestored sites. The average age of the restorations was 14.9 ± 7.1 years. Firmicutes was the most prevalent phylum at the restored sites (32% vs 20% of the reads of the unrestored sites, P = 0.016), and Actinobacteria at the unrestored sites (33% vs 18% of the reads of the restored sites, P = 0.01). Overall, sequences clustered into 573 operational taxonomic units (OTUs). Species richness of the restored sites was significantly higher than species richness of the unrestored sites (117 ± 32 and 96 ± 20 OTUs, respectively, P = 0.013). No associations between the metal composition and bacterial profiles were found. CONCLUSION: This study shows that metal-based restorations may enhance colonization of Firmicutes and the neighboring pocket may harbor more diverse microbial communities.

Impact of food odors signaling specific taste qualities and macronutrient content on saliva secretion and composition.

Olfactory food cues can induce appetite for similar food products in humans. Odors may thus signal essential information about a foods' composition such as taste or even macronutrient content and may stimulate specific physiological responses in anticipation of food intake. Several studies have shown that sensory food cues could stimulate saliva secretion. However, potential differences between food odors in their effect on saliva secretion, or the effects of olfactory stimulation on changes in saliva composition remain to be elucidated. To gain more insight, we conducted two studies to determine the influence of various odors, representing different taste qualities (study 1) and macronutrients (study 2), on salivary biomarkers. In study 1, 36 participants were randomly exposed to no-odor, non-food, and odors signaling sweet, savory, and sour taste. In study 2, 60 participants were randomly exposed to no-odor, non-food, and odors signaling carbohydrates, protein, fat, and low-calorie food. For each condition, whole-mouth saliva was collected and saliva secretion rate determined. Furthermore, we determined mouth-watering perception (subjective salivation), visco-elasticity (study 1 only), mucin concentration, α-amylase and lingual lipase activity (study 2 only). For both studies, linear mixed model analyses showed that saliva secretion rate significantly increased by food odor exposure compared to no-odor and non-food conditions. However, no changes in salivary composition were observed. These findings indicate that food odors play a crucial role in anticipatory saliva responses and can thereby affect subsequent eating behavior.

At least three phenotypes exist among periodontitis patients.

AIM: To identify phenotypes of periodontitis patients by the use of an unsupervised modelling technique (clustering), based on pre-treatment radiographic and microbiological characteristics. MATERIALS AND METHODS: This retrospective study included data from 392 untreated periodontitis patients. Co-regularized spectral clustering algorithm was used to cluster the patients. The resulting clusters were subsequently characterized based on their demographics, radiographic bone loss patterns and microbial data. RESULTS: The vast majority of patients fitted into one of the three main clusters (accuracy 90%). Cluster A (n = 18) was characterized by high prevalence and high proportions of Aggregatibacter actinomycetemcomitans, a trend for a more localized pattern of alveolar bone loss and young individuals. Clusters B (n = 200) and C (n = 135) differed clearly in disease severity patterns and smoking habits, but not in microbiological characteristics. CONCLUSION: On the basis of alveolar bone loss patterns and microbiological data, untreated periodontitis patients can be clustered into at least three phenotypes. These results should be validated in other cohorts, and the clinical utility needs to be explored on the basis of periodontal treatment outcomes and/or disease progression.

Interaction of lifestyle, behaviour or systemic diseases with dental caries and periodontal diseases: consensus report of group 2 of the joint EFP/ORCA workshop on the boundaries between caries and periodontal diseases.

Periodontal diseases and dental caries are the most common diseases of humans and the main cause of tooth loss. Both diseases can lead to nutritional compromise and negative impacts upon self-esteem and quality of life. As complex chronic diseases, they share common risk factors, such as a requirement for a pathogenic plaque biofilm, yet they exhibit distinct pathophysiologies. Multiple exposures contribute to their causal pathways, and susceptibility involves risk factors that are inherited (e.g. genetic variants), and those that are acquired (e.g. socio-economic factors, biofilm load or composition, smoking, carbohydrate intake). Identification of these factors is crucial in the prevention of both diseases as well as in their management. AIM: To systematically appraise the scientific literature to identify potential risk factors for caries and periodontal diseases. METHODS: One systematic review (genetic risk factors), one narrative review (role of diet and nutrition) and reference documentation for modifiable acquired risk factors common to both disease groups, formed the basis of the report. RESULTS & CONCLUSIONS: There is moderately strong evidence for a genetic contribution to periodontal diseases and caries susceptibility, with an attributable risk estimated to be up to 50%. The genetics literature for periodontal disease is more substantial than for caries and genes associated with chronic periodontitis are the vitamin D receptor (VDR), Fc gamma receptor IIA (Fc-γRIIA) and Interleukin 10 (IL10) genes. For caries, genes involved in enamel formation (AMELX, AMBN, ENAM, TUFT, MMP20, and KLK4), salivary characteristics (AQP5), immune regulation and dietary preferences had the largest impact. No common genetic variants were found. Fermentable carbohydrates (sugars and starches) were the most relevant common dietary risk factor for both diseases, but associated mechanisms differed. In caries, the fermentation process leads to acid production and the generation of biofilm components such as Glucans. In periodontitis, glycaemia drives oxidative stress and advanced glycation end-products may also trigger a hyper inflammatory state. Micronutrient deficiencies, such as for vitamin C, vitamin D or vitamin B12, may be related to the onset and progression of both diseases. Functional foods or probiotics could be helpful in caries prevention and periodontal disease management, although evidence is limited and biological mechanisms not fully elucidated. Hyposalivation, rheumatoid arthritis, smoking/tobacco use, undiagnosed or sub-optimally controlled diabetes and obesity are common acquired risk factors for both caries and periodontal diseases.

Java project on periodontal diseases: effect of vitamin C/calcium threonate/citrus flavonoids supplementation on periodontal pathogens, CRP and HbA1c.

OBJECTIVE: To assess in a periodontally diseased rural population deprived from regular dental care and having poor dietary conditions, the effect of vitamin C/calcium threonate/citrus flavonoids (VitC/Ca/Fl) supplementation on subgingival microbiota and plasma levels of vitamin C, HbA1c and hsCRP. MATERIAL & METHODS: The study population consisted of 98 subjects who previously participated in a prospective study on the natural history of periodontitis. Participants were instructed to consume one tablet/day containing 200 mg Ester C(®) calcium ascorbate, 25 mg calcium threonate and 100 mg citrus flavonoids for 90 days. Following parameters were evaluated: prevalence/amount of seven traditional periodontal pathogens, cytomegalovirus, Epstein-Barr virus (EBV); and plasma levels of vitamin C, HbA1c and hsCRP. RESULTS: After VitC/Ca/Fl supplementation, 100% of subjects showed normal plasma vitamin C values compared to 55% before. At baseline, 48% of subjects harboured Aggregatibacter actinomycetemcomitans, >97% the other periodontal pathogens and 73% EBV. Supplementation with VitC/Ca/F reduced the subgingival load of all studied bacteria (p-values: 0.014-0.0001) and EBV (p < 0.0001) substantially in all initially positive subjects. Plasma levels of HbA1c and hsCRP dropped in all subjects (p < 0.0001). CONCLUSION: This uncontrolled study suggested that supplemental VitC/Ca/Fl may be helpful in reducing subgingival numbers of periodontal pathogens and EBV, and promoting systemic health.

Java project on periodontal diseases: periodontal bone loss in relation to environmental and systemic conditions.

OBJECTIVE: To assess in a population deprived from regular dental care the relationship between alveolar bone loss (ABL) and environmental/systemic conditions. MATERIAL & METHODS: The study population consisted of subjects from the Purbasari tea estate on West Java, Indonesia. A full set of dental radiographs was obtained of each subject and amount of ABL was assessed. In addition, the following parameters were evaluated: plasma vitamin C, vitamin D3 , HbA1c and CRP, the haptoglobin phenotype, presence of putative periodontopathic bacteria and viruses, dietary habits, smoking and anthropometrics. RESULTS: In this population 45% showed vitamin C depletion/deficiency, 82% had vitamin D3 insufficiency/deficiency, 70% were in a pre-diabetic state, 6% had untreated diabetes, 21% had elevated CRP values ranging from 3.1 to 16.1 mg/l. Results of the regression analysis, including all above mentioned parameters, showed four significant predictors, explaining 19.8% of the variance of ABL. Number of Porphyromonas gingivalis cells and CRP values showed a positive relationship with ABL, whereas BMI and number of guava fruit servings were negatively related. CONCLUSION: Results confirm previous findings that elevated levels of P. gingivalis may be indicative for periodontitis progression. A new finding is that guava fruit consumption may play a protective role in periodontitis in a malnourished population.

Osteogenic Differentiation of Human Gingival Fibroblasts Inhibits Osteoclast Formation.

Gingival fibroblasts (GFs) can differentiate into osteoblast-like cells and induce osteoclast precursors to differentiate into osteoclasts. As it is unclear whether these two processes influence each other, we investigated how osteogenic differentiation of GFs affects their osteoclast-inducing capacity. To establish step-wise mineralization, GFs were cultured in four groups for 3 weeks, without or with osteogenic medium for the final 1, 2, or all 3 weeks. The mineralization was assessed by ALP activity, calcium concentration, scanning electron microscopy (SEM), Alizarin Red staining, and quantitative PCR (qPCR). To induce osteoclast differentiation, these cultures were then co-cultured for a further 3 weeks with peripheral blood mononuclear cells (PBMCs) containing osteoclast precursors. Osteoclast formation was assessed at different timepoints with qPCR, enzyme-linked immunosorbent assay (ELISA), TRAcP activity, and staining. ALP activity and calcium concentration increased significantly over time. As confirmed with the Alizarin Red staining, SEM images showed that the mineralization process occurred over time. Osteoclast numbers decreased in the GF cultures that had undergone osteogenesis. TNF-α secretion, a costimulatory molecule for osteoclast differentiation, was highest in the control group. GFs can differentiate into osteoblast-like cells and their degree of differentiation reduces their osteoclast-inducing capacity, indicating that, with appropriate stimulation, GFs could be used in regenerative periodontal treatments.

Subgingival microbiome in smokers and non-smokers in periodontitis: an exploratory study using traditional targeted techniques and a next-generation sequencing.

AIM: To compare the results of two targeted techniques to an open-ended technique in periodontitis patients, differentiated on the basis of smoking habit. MATERIALS & METHODS: Thirty periodontitis patients (15 smokers and 15 non-smokers) provided subgingival plaque samples for 16S rRNA gene amplicon sequencing, culturing and quantitative polymerase chain reaction (qPCR). RESULTS: No differences were found in the composition of the subgingival microbiome between smokers and non-smokers with culture and qPCR. With pyrosequencing, operational taxonomic units (OTUs) classified to genera Fusobacterium, Prevotella and Selenomonas were more abundant in smokers, while OTUs belonging to the genera Peptococcus and Capnocytophaga were more abundant in non-smokers. Principal coordinate analysis identified two clusters; one was composed mainly of smokers (80%) and revealed significantly lower taxonomic diversity, higher attachment loss and higher proportion of the genera Fusobacterium, Paludibacter and Desulfobubus. CONCLUSION: In periodontitis, there is a difference in the composition of the subgingival microbiome between smokers and non-smokers, as revealed by pyrosequencing. This difference was not identified by the targeted techniques. Low taxonomic diversity was associated with higher disease severity, especially in smokers. This supports the hypothesis of the ecological microbial-host interaction in the severity of periodontal disease.

Influence of titanium on in vitro fibroblast-Porphyromonas gingivalis interaction in peri-implantitis.

AIM: Titanium wear particles have been found in peri-implant tissues, but their role in the pathogenesis of peri-implantitis remains unclear. We aimed to determine the in vitro inflammatory responses of peri-implant granulation tissue fibroblasts (PIGFs) to titanium particles alone and in the presence of viable Porphyromonas gingivalis. MATERIALS & METHODS: Peri-implant granulation tissue fibroblasts were challenged either with TiO2 particles, P. gingivalis or a combination of TiO2 particles and P. gingivalis. Gene expression and protein production of pro-inflammatory mediators by PIGFs were measured with PCR and ELISA, respectively. RESULTS: Higher doses of TiO2 were toxic to PIGFs and in sub-toxic doses, TiO2 caused an increase in gene expression of tumour necrosis factor (TNF)-A and increased protein production of TNF-α, interleukin (IL)-6 and IL-8. A challenge with P. gingivalis alone induced gene expression of TNF-A, IL-1ß, IL-6 and IL-8. A combined challenge with TiO2 and P. gingivalis caused a stronger increase in gene expression of TNF-A and protein production of TNF-α and MCP-1 than P. gingivalis alone. CONCLUSIONS: TiO2 particles and P. gingivalis, individually, can induce pro-inflammatory responses in PIGFs. Furthermore, TiO2 particles and viable P. gingivalis further enhance gene expression and production of TNF-α by PIGFs. Therefore, Ti wear particles in the peri-implant tissues in combination with P. gingivalis infection may contribute to the pathogenesis of peri-implantitis by enhancing the inflammation in peri-implant tissues.