Subgingival scaling and root planing during minimally invasive periodontal surgery: A randomized controlled split-mouth trial.

BACKGROUND: The purpose of this randomized, controlled split-mouth study was to evaluate a videoscope as a visual adjunct to scaling and root planing when utilized in combination with minimally invasive surgery. METHODS: Twenty-five pairs (89 interproximal surfaces) of periodontally hopeless teeth planned for extraction were scaled and root planed with minimal surgical access using surgical loupes (control) or adjunctive use of a videoscope (test). Teeth were extracted with minimal trauma, stained with methylene blue, and photographed with a digital microscope for analysis. The primary outcome of residual calculus was calculated as a percentage of the total interproximal area of interest. Secondary outcomes included treatment time, as well as residual calculus according to probing depth, tooth location, and treatment date. Data were analyzed using Student's paired t-tests, two-way analyses of variance, and Spearman's correlation tests. RESULTS: Residual calculus area was 2.61% on control and 2.71% on test surfaces with no significant difference between groups. Subgroup analysis showed no difference in residual calculus between groups at moderate or deep sites. Treatment time per surface was significantly longer in the test group compared to the control group. Treatment order, tooth location, and operator experience did not significantly affect the primary outcome. CONCLUSIONS: Though the videoscope provided excellent visual access, it did not improve the efficacy of root planing for flat interproximal surfaces during minimally invasive periodontal surgery. Small amounts of calculus remain after instrumentation even with minimal surgical access and when root surfaces appear visually clean and tactilely smooth.

Interdental oral hygiene interventions elicit varying compositional microbiome changes in naturally occurring gingivitis: Secondary data analysis from a clinical trial.

AIM: To evaluate the effect of different oral irrigators on the sub-gingival microbiome composition in patients with naturally occurring plaque-induced gingivitis. MATERIALS AND METHODS: Sub-gingival plaque was collected from adults participating in a clinical trial assessing the efficacy of oral hygiene with two different oral irrigators (Waterpik Water Flosser [Group 1] and Oral-B Water Flosser [Group 2]) versus dental flossing (Group 3) for microbiome analysis. Plaque samples were reflective of naturally occurring plaque-induced gingivitis at baseline and of gingival health at the endpoint (4 weeks). Clinical measures of gingival inflammation were collected, and the sub-gingival microbiome was analysed by 16S rRNA sequencing to identify amplicon sequence variants. RESULTS: Oral hygiene instruction with self-performed manual toothbrushing and water-jet irrigation led to significant reductions in inflammation for all groups; both oral irrigators outperformed flossing in bleeding-on-probing reduction (p < .001). Microbiome diversity of sub-gingival plaque remained relatively stable over time, but significant changes were noted in certain taxa, consistent with increases in the relative abundance of commensals and reductions in late colonizers and periodontal pathogens in the water-jet groups. CONCLUSIONS: Reduction in gingival inflammation at 4 weeks within the water-jet groups is accompanied by slight but critical changes in microbiome composition. Although biodiversity does not substantially change within 4 weeks during the resolution of naturally induced gingivitis, significant relative increases in commensal early colonizers such as Streptococcus, Veillonella and Fusobacterium were accompanied by a shift towards a less anaerobic microbiota associated with return to health. These changes were contingent upon the type of interdental hygiene, with Group 1 exhibiting more significant alterations in microbiome composition towards a periodontal-health-compatible community.

Localized microbially induced inflammation influences distant healthy tissues in the human oral cavity.

Variation in human immune response to the same bacterial or viral pathogen is well established in the literature. Variation in immune response to microbial challenge has also been observed within the human oral cavity. Our recent study focused on characterizing observed variations in microbially induced gingival inflammation-resulting in three distinct clinical Inflammatory Responder Types (IRTs): High-IRT, Low-IRT, and Slow-IRT. Here, we applied a high-resolution temporal multiomic analysis during microbially induced inflammation in order to characterize the effects of localized oral inflammation on distant healthy tissues in young healthy adults. Our results highlight a nonlocalized subclinical effect with alterations in proinflammatory host mediators and an ecological shift toward dysbiosis within the subgingival microbiome in an IRT-dependent manner-despite maintained oral hygiene. Our results provide mechanistic insight into how healthy tissues within humans are influenced by distant localized inflammation and may ultimately become susceptible to disease.

Assessment of titanium release following non-surgical peri-implantitis treatment: A randomized clinical trial.

BACKGROUND: Peri-implantitis is a frequent finding. Initial treatment involves non-surgical debridement of the implant surface. Recent studies have found a correlation between titanium (Ti) particle release and peri-implantitis, yet there is a dearth of information regarding the effect of various non-surgical instrumentation on particle release or peri-implantitis resolution. METHODS: Patients with peri-implantitis were recruited for a randomized, blinded, parallel-group clinical trial. The implants were randomized to treatment composed of Ti curettes ("Mech" group) or implant-specific treatment composed of rotary polymer microbrushes ("Imp" group). Ti release in submucosal peri-implant plaque pre- and 8 weeks posttreatment was assessed as the primary outcome. Peri-implant probing depth, bleeding on probing, and suppuration on probing were evaluated and compared between groups. RESULTS: Thirty-four participants completed treatment; 18 were randomized to the Mech group and 16 to the Imp group. The groups were comparable for Ti levels and probing depths at baseline. A trend was noted for 10-fold greater Ti dissolution in the Mech group posttreatment compared to the Imp group (p = 0.069). The Imp group had a significant reduction in probing depth posttreatment (p = 0.006), while the Mech group reduction was not significant. CONCLUSION: Peri-implantitis treated non-surgically with implant-specific instruments (Imp group) had a significantly greater decrease in probing depth versus the Mech treatment group. This improvement was linked with a trend for less Ti release to the peri-implant plaque by the non-abrasive treatment.

A randomized controlled trial evaluating the effect of epithelial removal on free soft tissue autograft healing.

BACKGROUND: The purpose of this study is to determine if there is a difference in dimensional change of a free soft tissue autograft (FSTA) with epithelium compared to without epithelium. The secondary aim is to determine the patient and professional evaluation of color match and graft texture between the two groups. METHODS: Patients with ≤2 mm keratinized tissue indicated for a FSTA were randomly assigned to control group (FSTA with epithelium) or test group (de-epithelialized FSTA). The vertical and horizontal measurements of the grafts were taken at surgery, and 1, 3, and 6 months postoperatively. Patients were asked to evaluate the color match at each postoperative time point on a 21-step Numeric Rating Scale (NRS-21). Professional assessment of color match and graft texture were evaluated on images at the same time points. RESULTS: Forty-six patients and 55 grafts were included in the study. For change in graft height, width, and area, there were no significant differences between the treatment groups at any time point. Graft height and area in both groups decreased significantly from baseline to month 1 (p < .001), but no other difference was significant over time. When patients and professionals used the NRS-21 for evaluation of color match between the graft site and the surrounding soft tissue, there was no significant difference between the treatment groups. Similarly, evaluation of texture match on color images and black-and-white images revealed no significant differences between or within groups. CONCLUSION: De-epithelialized FSTA showed no difference in dimensional change or color and texture match compared to FSTA with epithelium.

Periodontitis Risk Factors in Adults with Cystic Fibrosis: A pilot study.

Purpose Individuals with cystic fibrosis (CF) present with multiple condition-specific risk factors for periodontitis including CF-related diabetes, chronic inhaled treatments that induce xerostomia, and increased systemic inflammation because of frequent lung infections. General factors like age, oral hygiene, and diet may also contribute to the risk of periodontitis. However the relative importance of these specific risk factors and periodontitis in individuals with CF has not yet been evaluated. The purpose of this pilot study was to assess the associations between CF condition-specific and general risk factors and the prevalence of periodontitis in adults with CF.Methods This cross-sectional pilot study was designed to assess a multifactorial model of periodontitis risk factors in a population in adults with CF who were recruited from the University of Washington Adult CF center. Periodontitis was defined using the Centers for Disease Control and Prevention and the American Academy of Periodontology (CDC/AAP) case definition. Risk factors included condition-specific and general factors. Differences between participants with moderate/severe periodontitis and those with no/mild periodontitis was assessed using the Mann-Whitney test, the Fisher's exact test, and the exact chi-square test (α=0.05).Results Thirty-two participants were enrolled. Twenty-eight percent of the participants had moderate periodontitis, 72% had no/mild periodontitis; none of the participants had severe periodontitis. There were no significant differences in condition-specific factors between between the two study groups. Participants with moderate periodontitis were older (p=0.028) and reported daily flossing in higher proportions than those with no/mild periodontitis (p=0.023).Conclusions The findings from this pilot study suggest that future research is needed to determine whether sociodemographic and other general risk factors are more important contributors to periodontitis risk than CF-specific factors.

Wound healing after ridge preservation: A randomized controlled trial on short-term (4 months) versus long-term (12 months) histologic outcomes.

BACKGROUND: The amount of time it takes for bone allograft particles to be replaced with new vital bone during ridge preservation is unclear. The purpose of this article was to compare the wound healing and vital bone formation following ridge preservation using a combination allograft of 70% mineralized and 30% demineralized freeze-dried bone allograft at 4 months (short-term, ST) versus 12 months (long-term, LT). METHODS: Fifty-seven patients were enrolled in the study who required extraction of a single tooth (excluding second and third molars) and were planned for replacement with a dental implant. After tooth extraction, all sites were grafted with a combination allograft procured from a single donor, and patients were randomized into the ST or LT healing groups. Patients returned for implant placement and an 8-mm bone core biopsy was harvested using a trephine drill during initial implant osteotomy preparation. The cores were then analyzed histologically to determine the percentages of vital bone formation, residual graft particles, and connective tissue/other. RESULTS: There was significantly greater vital bone formation in the LT group (51.38%) compared with the ST group (31.39%) (p = 0.0025) and significantly fewer residual graft particles in the LT group (18.04%) compared with the ST group (40.38%). CONCLUSIONS: A longer healing time following ridge preservation results in more vital bone formation and less residual graft particles at the time of implant placement. However, residual allograft material still remains at 12 months after ridge preservation.

Clinical outcomes of retention of the buccal root section combined with immediate implant placement: A systematic review of longitudinal studies.

INTRODUCTION: Immediate implant placement in conjunction with partial extraction therapy has been shown to result in functional osseo- and dento-integration with partial preservation of the periodontal ligament (PDL) in humans. Strategic buccal root retention for PDL preservation is a biologically driven procedure that maintains alveolar ridge dimensions and esthetics, while allowing for implant placement. The aim of this study was to conduct a systematic review of longitudinal clinical outcomes of PDL-mediated ridge preservation in conjunction with implant placement in adults, compared with conventional immediate implant placement with total extractions. The primary outcome for this study was marginal bone level (MBL) changes after strategic buccal root retention implant placement techniques. MATERIALS AND METHODS: To address a predefined PICOS question, a systematic search of randomized clinical trials and cohort studies with at least 10 participants per group and a minimum 12-month follow-up was conducted. A two-phase systematic selection strategy, data extraction, and risk of bias assessment, was performed independently and in duplicate. Randomized trials were quantitatively analyzed in a meta-analysis. RESULTS: Ten human studies fulfilled the predefined criteria and were included; three clinical trials and seven cohort studies, for a total of 506 patients and 587 implants. PDL-mediated implant placement of single-rooted periodontally healthy teeth was found to reduce marginal peri-implant bone loss and buccal plate changes as compared to conventional immediate implants across studies, while implant survival and success rates were comparable between the two procedures. A meta-analysis found that bone changes were significantly less when retention of the buccal root section was performed as compared to total extractions (standardized mean difference: [-4.53, -0.11]); the three clinical trials were, however, largely heterogeneous (I2 : 93.1%; Q = 28.98, p < 0.001). CONCLUSION: Strategic retention of the buccal root section has a benefit in terms of dimensional ridge stability over conventional immediate implantation when implemented in carefully selected cases of single-rooted teeth.

Comparison of antibacterial and antibiofilm activity of bioactive glass compounds S53P4 and 45S5.

BACKGROUND: Bone loss and deformation due to damage caused by injury or recurrent invasive infections presents a major clinical obstacle. While bone substitute biomaterials promote osseous tissue regeneration, their application in sites complicated by microbial infections such as osteomyelitis, is limited. Bioactive glass biomaterials (Bioglass) have been shown to have efficient mechanisms of repairing the integrity of bone, while inhibiting growth of a range of bacterial strains. There are several commercially available bioactive glass compounds, each with a unique chemical composition. One compound in particular, S53P4, has demonstrated antimicrobial effects in previous studies but the antimicrobial activity of the parent compound 45S5 has not been investigated. RESULTS: To assess whether antimicrobial activity is common among bioglass compounds, 45S5-the parent compound, was evaluated in comparison to S53P4 for antibacterial and antibiofilm effects against multiple strains of aerobic and anaerobic bacteria associated with various types of osteomyelitis. Experiments of antimicrobial effects in liquid cultures demonstrated that both compounds were antimicrobial against various microbial genera including S. gordonii, V. parvula, P. aeruginosa and MRSA; particles of the smallest size (32-125 µm) invariably showed the most robust antimicrobial capabilities. When employed against biofilms ecological biofilms grown on hydroxyapatite, 45S5 particles produced a stronger reduction in biofilm mass compared to S53P4 particles when considering small particle ranges. CONCLUSION: We found that 45S5 seems to be as effective as S53P4 and possibly even more capable of limiting bacterial infections. The efficacy of bioactive glass was not limited to inhibition of planktonic growth, as it also extended to bacterial biofilms. The increased antibacterial activity of 45S5 compared to S53P4 is true for a variety of size ranges.

C3-targeted host-modulation approaches to oral inflammatory conditions.

Periodontitis is an inflammatory disease caused by biofilm accumulation and dysbiosis in subgingival areas surrounding the teeth. If not properly treated, this oral disease may result in tooth loss and consequently poor esthetics, deteriorated masticatory function and compromised quality of life. Epidemiological and clinical intervention studies indicate that periodontitis can potentially aggravate systemic diseases, such as, cardiovascular disease, type 2 diabetes mellitus, rheumatoid arthritis, and Alzheimer disease. Therefore, improvements in the treatment of periodontal disease may benefit not only oral health but also systemic health. The complement system is an ancient host defense system that plays pivotal roles in immunosurveillance and tissue homeostasis. However, complement has unwanted consequences if not controlled appropriately or excessively activated. Complement overactivation has been observed in patients with periodontitis and in animal models of periodontitis and drives periodontal inflammation and tissue destruction. This review places emphasis on a promising periodontal host-modulation therapy targeting the complement system, namely the complement C3-targeting drug, AMY-101. AMY-101 has shown safety and efficacy in reducing gingival inflammation in a recent Phase 2a clinical study. We also discuss the potential of AMY-101 to treat peri-implant inflammatory conditions, where complement also seems to be involved and there is an urgent unmet need for effective treatment.

Biological mechanisms underlying complications related to implant site preparation.

Implant site preparation is a critical stage of implant surgery that may underpin various complications related to implant surgery. This review discusses the latest available scientific information on risk factors related to implant site preparation. The role of the drilling process in relation to the density of the available alveolar bone, the effects of insertion torque on peri-implant osseous healing, and implant-related variables such as macrodesign and implant-abutment connection are all factors that can influence implant success. Novel information that links osteotomy characteristics (including methods to improve implant initial stability, the impact of drilling speed, and increase of the implant insertion torque modifying the bone-implant interface) with the appropriate instrumentation techniques will be discussed, as well as interactions at the bone-biomaterial interface that may lead to biologic complications mediated by implant dissolution products.

Long-term preservation of ridge dimension following tooth extraction and ridge preservation: A randomized controlled trial of healing at 4- and 12-month healing time points.

BACKGROUND: To date, the efficacy of ridge preservation in the maintenance of the residual alveolar ridge dimension beyond 6 months after treatment is unknown. The purpose of this study was to compare the differences in alveolar ridge dimensional change following ridge preservation between 4- and 12-month healing time points using cone-beam computed tomography (CBCT). METHODS: Fifty seven patients planned for tooth extraction and implant placement were enrolled. Following extraction, ridge preservation was performed. CBCT scans were taken within 72 hours following extraction with a customized resin stent containing a fixed radiographic marker. At either 4 months (short-term, ST group) or 12 months (long-term, LT group) after ridge preservation, patients had a second CBCT taken and an implant placed. Changes in ridge height and width were measured using the standardized radiographic marker. RESULTS: No significant differences were detected between the ST and LT groups in loss of buccal and lingual ridge height. Similarly, when adjusted for baseline ridge width, no significant differences were detected in ridge width loss at 3, 5, and 7 mm apical to the crest between the ST and LT groups. CONCLUSIONS: The efficacy of ridge preservation in the maintenance of ridge width and height at the 12-month time point is similar to that of the 4-month time point. Clinicians may feel confident that a delay in implant placement for up to a year has no significant negative impact on the height and width of the healed ridge.

Clinical performance of hydrophilic, titanium-zirconium dental implants in patients with well-controlled and poorly controlled type 2 diabetes: One-year results of a dual-center cohort study.

BACKGROUND: This study assessed the clinical performance of hydrophilic dental implants in a patient cohort with type 2 diabetes mellitus (T2DM). METHODS: Subjects with T2DM of ≥2-years duration were allocated to either the well-controlled (WC; HbA1c ≤ 7.0%,) or poorly-controlled (PC; 7.5 < HbA1c < 10%) groups in a dual-center, prospective cohort study. Each subject received a single, titanium-zirconium (Ti-Zr) dental implant with a chemically-modified, hydrophilic (modSLA) surface in a posterior mandibular site. Postoperatively, subjects were followed at 1, 2, 4, 8, and 12-week intervals. Post-loading, subjects were followed at 3, 6, and 12-months. Clinical and radiographic parameters of implant success, and dental patient-reported outcomes were collected. RESULTS: Twenty-one dental patients (NWC  = 11; NPC  = 10; mean age: 66.8 ± 7.5 years) were enrolled and the 1-year implant success rate was 100%. Peri-implant bone levels were stable with 0.15 ± 0.06 mm mean marginal loss at 1 year without significant inter-group differences (P = 0.79). Postoperative pain was minimal at 1-week, and OHIP-5 scores decreased significantly over time as compared with preoperative levels (P < 0.001) suggesting significant improvement in patient-perceived oral health following implant therapy. CONCLUSIONS: Elevated HbA1c levels > 7.5% did not compromise 1-year success rates, or oral health-related quality of life in PC patients receiving modSLA, Ti-Zr implants. Given that implant placement up to 10% HbA1c significantly enhanced oral health-related quality of life without complications or morbidity, the safety and efficacy of implants to improve oral function in T2DM is supported, even without ideal glycemic control.

Radiographic evaluation of a novel bone adhesive for maintenance of crestal bone around implants in canine oversized osteotomies.

BACKGROUND: A novel bone adhesive (tetracalcium phosphate and O-phospho-L-serine) has been developed as an osteoconductive, biodegradable bone-adherent material. The purpose of this study was to evaluate the maintenance of crestal bone/material level by standardized radiographs. METHODS: This was a randomized, controlled, three arm, prospective study. Twenty-six mixed breed hound dogs were included in this study. Three implants were placed on either side of the mandible with either bone adhesive (BA), bovine bone mineral (BBM), or no biomaterial (negative control [NC]). Standardized periapical radiographs were taken immediately after implant placement and at every month up to 1 year. The vertical distance between the implant platform to the first radiopaque material on both the mesial and distal surfaces were measured and crestal bone/material level changes were analyzed. RESULTS: The crestal bone/material level adjacent to BA was stable and maintained throughout the study. There were statistically significant differences found between BA and NC in terms of maintenance of crestal bone levels at any given timepoint. CONCLUSION: This study demonstrated that BA maintained crestal bone levels and had a similar ability to maintain that level over 1 year compared with BBM.

Human variation in gingival inflammation.

Oral commensal bacteria actively participate with gingival tissue to maintain healthy neutrophil surveillance and normal tissue and bone turnover processes. Disruption of this homeostatic host-bacteria relationship occurs during experimental gingivitis studies where it has been clearly established that increases in the bacterial burden increase gingival inflammation. Here, we show that experimental gingivitis resulted in three unique clinical inflammatory phenotypes (high, low, and slow) and reveal that interleukin-1ß, a reported major gingivitis-associated inflammatory mediator, was not associated with clinical gingival inflammation in the slow response group. In addition, significantly higher levels of Streptococcus spp. were also unique to this group. The low clinical response group was characterized by low concentrations of host mediators, despite similar bacterial accumulation and compositional characteristics as the high clinical response group. Neutrophil and bone activation modulators were down-regulated in all response groups, revealing novel tissue and bone protective responses during gingival inflammation. These alterations in chemokine and microbial composition responses during experimental gingivitis reveal a previously uncharacterized variation in the human host response to a disruption in gingival homeostasis. Understanding this human variation in gingival inflammation may facilitate the identification of periodontitis-susceptible individuals. Overall, this study underscores the variability in host responses in the human population arising from variations in host immune profiles (low responders) and microbial community maturation (slow responders) that may impact clinical outcomes in terms of destructive inflammation.

Cytocompatibility Properties of an Herbal Compound Solution Support I n vitro Wound Healing.

The aim of this study was to evaluate the cytocompatibility of an herbal extract compound oral rinse [StellaLife VEGA (SLife)] against relevant human cellular models of oral surgical wound healing. SL was compared to the gold standard for peri-/post-operative oral surgical use, i.e., Chlorhexidine (CHX) and to a commonly utilized essential-oil (EO) based antiseptic rinse. Fibroblasts and primary oral stem cells of the apical papilla (SCAPs) were employed to assess its comparative cytotoxicity to the active comparator antiseptic rinses and its effects on wound healing in vitro. In cytotoxicity assays, multiple timepoints were tested ranging from clinically relevant of 60-s rinsing to protracted challenge of up to 5 min, to determine dose-dependent toxicity. The SLife group consistently demonstrated minimal cytotoxicity as compared to active comparators across experimental timepoints and different cells lines. At concentrations up to 20% v/v SLife-challenged fibroblasts and SCAPs demonstrated no significant toxicity as compared to unstimulated controls (p > 0.05). When assessing wound healing, a scratch wound assay revealed significantly accelerated cell migration for SLife as compared to CHX (p < 0.05). Notably, all active comparator antiseptic rinses affected wound healing responses by significantly reducing total collagen deposition after intermittent "rinsing" intervals that simulated post-surgical oral rinsing. Nonetheless, intermittent as well as continuous challenge of cells with SLife had a positive effect in functional collagen assays. An herbal extract compound-based oral rinse was found to be cytocompatible to cells critical to oral wound healing and to promote fibroblast migration and differentiation, contrary to existing antiseptic rinses that lack selective cytotoxicity.

Peri-implantitis is not periodontitis: Scientific discoveries shed light on microbiome-biomaterial interactions that may determine disease phenotype.

Peri-implantitis is an immune-mediated biological complication that is attributed to bacterial biofilms on the implant surface. As both periodontitis and peri-implantitis have similar inflammatory phenotypes when assessed cross-sectionally, treatment protocols for peri-implantitis were modeled according to those used for periodontitis. However, lack of efficacy of antimicrobial treatments targeting periodontal pathogens coupled with recent discoveries from open-ended microbial investigation studies create a heightened need to revisit the pathogenesis of peri-implantitis compared with that of periodontitis. The tale of biofilm formation on intraoral solid surfaces begins with pellicle formation, which supports initial bacterial adhesion. The differences between implant- and tooth-bound biofilms appear as early as bacterial adhesion commences. The electrostatic forces and ionic bonding that drive initial bacterial adhesion are fundamentally different in the presence of titanium dioxide or other implant alloys vs mineralized organic hydroxyapatite, respectively. Moreover, the interaction between metal surfaces and the oral environment leads to the release of implant degradation products into the peri-implant sulcus, which exposes the microbiota to increased environmental stress and may alter immune responses to bacteria. Clinically, biofilms found in peri-implantitis are resistant to beta-lactam antibiotics, which are effective against periodontal communities even as monotherapies and demonstrate a composition different from that of biofilms found in periodontitis; these facts strongly suggest that a new model of peri-implant infection is required.

Immunomodulatory effects of Nd:YAG (1064 nm) and diode laser (810 nm) wavelengths to LPS-challenged human gingival fibroblasts.

OBJECTIVE: Human gingival fibroblasts (hGFs) are involved in inflammatory responses to bacteria by recognizing pathogen-associated molecular patterns. In search of host modulation strategies to increase LPS tolerance, Low level laser therapy (LLLT) has been suggested as an alternative treatment that reduces periodontal tissue inflammation. In this study, we investigate whether 810 nm (diode) and 1064 nm (Nd:YAG) laser wavelengths, modulate pro-inflammatory responses to LPS challenges in hGFs. DESIGN: Primary hGFs were challenged with Porphyromonas gingivalis LPS and irradiated with either Diode (810 nm) or with Nd:YAG (1064 nm) lasers. Cell cultures were examined for cell proliferation by MTT assay and IL-6 and IL-8 expression by qPCR at 24, 48 and 72 h. IL-6 and IL-8 protein levels were detected via ELISA. RESULTS: Naïve hGF populations irradiated with both Diode 810 nm and Nd:YAG 1064 nm lasers demonstrated cellular proliferation (p < 0.05), but LLLT did not affect cellular viability in LPS-challenged cells. IL-6 and IL-8 gene expression levels revealed significant anti-inflammatory effects of irradiation with both examined wavelengths on hGFs challenged with P. gingivalis LPS. Protein levels of these cytokines were increased by LPS challenge. Treatment with LLLT inhibited this increase for both wavelengths evaluated in the study at a statistically significant level particularly for the first 48 h. CONCLUSIONS: The present study demonstrates a modulatory effect of LLLT using both 810 nm diode and Nd:YAG 1064 nm lasers in gingival fibroblasts by decreasing the production of IL-6, IL-8 in response to LPS.

Clinically Healthy Human Gingival Tissues Show Significant Inter-individual Variability in GCF Chemokine Expression and Subgingival Plaque Microbial Composition.

Aim: Clinically healthy gingival tissue is maintained through controlled regulation of host defense mechanisms against plaque biofilm overgrowth. One key component is the transit of neutrophils from the vasculature into gingival tissue where the expression of different neutrophil chemokines are tightly regulated. This cross-sectional study examines the inter-individual variability in chemokine profiles within gingival crevicular fluid (GCF) in relation to the subgingival bacterial community in a state of gingival health. Methods: Gingival crevicular fluid and subgingival plaque samples were collected from mesiobuccal surfaces of all six Ramfjord teeth of 20 systemically healthy individuals (14.55 ± 1.67 years). A multiplex immunoassay was carried out to quantify the expression of 40 different chemokines in the healthy gingival tissue. Neutrophils were assessed indirectly by myeloperoxidase (MPO) in GCF using traditional ELISA. Characterization of healthy subgingival plaque was conducted with the Illumina Miseq targeting the 16S rRNA gene. Results: In health, there are distinct variations within individual gingival crevicular fluid chemokine expression profiles, as well as in the concentration of neutrophils, that divided the participants into high or low chemokine expressing groups. Specifically, key differences were identified within MIF (2683.54 ± 985.82 pg per 30-s sample), IL-8/CXCL8 (170.98 ± 176.96 pg per 30-s sample), Gro-α/CXCL1 (160.42 ± 94.21 pg per 30-s sample), ENA-78/CXCL5 (137.76 ± 76.02 pg per 30-s sample), IL-1ß (51.39 ± 37.23 pg per 30-s sample), TNF-α (1.76 ± 1.79 pg per 30-s sample), and IFN-γ (0.92 ± 0.54 pg per 30-s sample). Of these identified chemokines, the highest correlation was associated between IL-8/CXCL8 and neutrophils (r = 0.54, p = 0.014). Furthermore, species characterization of healthy subgingival plaque revealed significant inter-individual variability that identified two unique groups unrelated to the previously identified chemokine groups. Conclusion: The lack of concordance between the microbial composition and chemokine profile during health may be a reflection of the unique microbial composition of each individual coupled with variations within their host response, emphasizing the vast complexity of the defense mechanisms in place to maintain gingival health.

Veillonellae: Beyond Bridging Species in Oral Biofilm Ecology.

The genus Veillonella comprises 16 characterized species, among which eight are commonly found in the human oral cavity. The high abundance of Veillonella species in the microbiome of both supra- and sub-gingival biofilms, and their interdependent relationship with a multitude of other bacterial species, suggest veillonellae to play an important role in oral biofilm ecology. Development of oral biofilms relies on an incremental coaggregation process between early, bridging and later bacterial colonizers, ultimately forming multispecies communities. As early colonizer and bridging species, veillonellae are critical in guiding the development of multispecies communities in the human oral microenvironment. Their ability to establish mutualistic relationships with other members of the oral microbiome has emerged as a crucial factor that may contribute to health equilibrium. Here, we review the general characteristics, taxonomy, physiology, genomic and genetics of veillonellae, as well as their bridging role in the development of oral biofilms. We further discuss the role of Veillonella spp. as potential "accessory pathogens" in the human oral cavity, capable of supporting colonization by other, more pathogenic species. The relationship between Veillonella spp. and dental caries, periodontitis, and peri-implantitis is also recapitulated in this review. We finally highlight areas of future research required to better understand the intergeneric signaling employed by veillonellae during their bridging activities and interspecies mutualism. With the recent discoveries of large species and strain-specific variation within the genus in biological and virulence characteristics, the study of Veillonella as an example of highly adaptive microorganisms that indirectly participates in dysbiosis holds great promise for broadening our understanding of polymicrobial disease pathogenesis.