Salivary detection of periodontopathic bacteria and periodontal health status in dental students

Objective: Saliva may become a potential source of contamination through vertical and horizontal transmissions as well as cross-infections. This study aims to use saliva as a screening tool to detect putative periodontal pathogens in a young population with fairly good oral hygiene

Clinical evaluation of marginal bone loss and stability in two types of submerged dental implants.

Purpose: The aim of this prospective clinical trial was to compare the three-dimensional marginal bone level, implant stability, and peri-implant health of two types of submerged dental implants that were restored with matching or platform-switched abutments. Materials and Methods: Twenty-five subjects were recruited (test group: 43 implants with internal conical connection and back-tapered collar carrying a platform-switched abutment; control group: 50 implants carrying a matched-platform abutment). Implant uncovering and conventional loading were performed after 3 months of healing, and the total observation time was 15 months. Marginal bone levels, resonance frequency analysis, insertion torque, and peri-implant health indices were recorded and analyzed statistically. Results: The cumulative implant survival rate was 100%. At the second-stage surgery, bone levels were similar between groups. One year after loading, mean crestal bone loss was 0.35 +/- 0.13 mm for test implants and 0.83 +/- 0.16 mm for control implants, a significant difference. Primary stability was significantly higher in the test group than in the control group, but this difference disappeared after 3 months of healing prior to loading. Between-group differences for peri-implant health indices were negligible. Conclusions: Both implant systems had the same survival rates. Implants with a built-in platform switch and conical connection with back-tapered collar design achieved higher primary stability at insertion and less bone resorption after 15 months

Efficacy of granulocyte macrophage colony-stimulating factor on oral mucositis

OBJECTIVE

Gingival Perfusion and Tissue Biomarkers During Early Healing of Postextraction Regenerative Procedures: A Prospective Case Series

Background—Post-extraction alveolar bone loss, mostly affecting the buccal plate, occurs despite regenerative procedures. To better understand possible determinants, this prospective case series assessed gingival blood perfusion and tissue molecular responses in relation to postextraction regenerative outcomes. Methods—Adults scheduled to receive bone grafting in maxillary, non-molar, single tooth extraction site were recruited. Clinical documentation included probing pocket depth (PD), keratinized tissue width (KT), tissue biotype (TB), plaque (P) and bleeding. Wound closure was clinically evaluated. Gingival blood perfusion was measured by Laser Doppler Flowmetry (LDF). Wound fluid (WF) and gingival biopsies were analyzed for protein levels and gene expression, respectively, of relevant molecular markers. Bone healing outcomes were determined radiographically (Cone Beam Computerized Tomography; CBCT). Healing was followed for 4 months. Results—Data from 15 patients (50 ± 5 years, 8 males) are reported. Postoperatively, neither complications nor changes in PD, KT or TB were observed. Postoperatively, LDF revealed decreased perfusion followed by hyperemia that persisted 1 month (p≤0.05). WF levels of angiopoietin-2, interleukin-8, tumor necrosis factor-α, and vascular endothelial growth factor peaked on day 6 (p≤0.05) and decreased thereafter. Only interleukin-8 and tumor necrosis factor-α exhibited increased gene expression. Linear bone changes were negligible. Volumetric bone changes were minimal but statistically significant, with more bone loss when membrane was used (p=0.05). Conclusion—Gingival blood perfusion following post-extraction bone regenerative procedures follows an ischemia-reperfusion model. Transient increases in angiogenic factor levels and prolonged hyperemia characterize the soft tissue response. These soft tissue responses do not determine radiographic bone changes

Bone Grafting History Affects Soft Tissue Healing Following Implant Placement

Background This study aimed to determine and compare soft tissue healing outcomes following implant placement in grafted (GG) and non-grafted bone (NGG). Methods Patients receiving single implant in a tooth-bound maxillary non-molar site were recruited. Clinical healing was documented. Volume and content of wound fluid (WF; at 3, 6, and 9 days) were compared with adjacent gingival crevicular fluid (GCF; at baseline, 1, and 4 months). Buccal flap blood perfusion recovery and changes in bone thickness were recorded. Linear mixed model regression analysis and generalized estimating equations with Bonferroni adjustments were conducted for repeated measures. Results Twenty-five patients (49 ± 4 years; 13 males; nine NGG) completed the study. Soft tissue closure was slower in GG (P \u3c 0.01). Differential response in WF/GCF protein concentrations was detected for ACTH (increased in GG only) and insulin, leptin, osteocalcin (decreased in NGG only) at day 6 (P ≤0.04), with no inter-group differences at any time(P \u3e 0.05). Blood perfusion rate decreased immediately postoperatively (P \u3c 0.01, GG) followed by 3-day hyperemia (P \u3e 0.05 both groups). The recovery to baseline values was almost complete for NGG whereas GG stayed ischemic even at 4 months (P = 0.05). Buccal bone thickness changes were significant in GG sites (P ≤ 0.05). Conclusion History of bone grafting alters the clinical, physiological, and molecular healing response of overlying soft tissues after implant placement surgery

Comparison of Azithromycin and Amoxicillin Before Dental Implant Placement: An Exploratory Study of Bioavailability and Resolution of Postoperative Inflammation

BACKGROUND: Studies suggest that a single prophylactic dose of amoxicillin reduces early implant complications, but it is unclear whether other antibiotics are also effective. This study compared the local antimicrobial and anti-inflammatory effects resulting from a single dose of azithromycin or amoxicillin prior to surgical placement of one-stage dental implants. METHODS: Healthy adult patients requiring one-stage dental implant placement were randomly allocated to receive either 2g amoxicillin (n=7) or 500mg azithromycin (n=6) prior to surgery. Peri-implant crevicular fluid (PICF) samples from the new implant and gingival crevicular fluid (GCF) from adjacent teeth were sampled on postoperative days 6, 13 and 20. Inflammatory mediators in the samples were analyzed by immunoassay and antibiotic levels were measured by bioassay. RESULTS: On day 6, azithromycin concentrations in GCF and PICF were 3.39±0.73μg/ml and 2.77±0.90μg/ml, respectively, while amoxicillin was below the limit of detection. During early healing, patents in the azithromycin group exhibited a significantly greater decrease in GCF volume (p=0.03, ANOVA). At specific times during healing, the azithromycin group exhibited significantly lower levels of IL-6 and IL-8 in GCF than the amoxicillin group and exhibited significantly lower levels of G-CSF, IL-8, MIP-1β and IP-10 in PICF. CONCLUSIONS: Azithromycin was available at the surgical site for a longer period of time than amoxicillin, and patients taking azithromycin exhibited lower levels of specific pro-inflammatory cytokines and chemokines in GCF and PICF. Thus, preoperative azithromycin may enhance resolution of postoperative inflammation to a greater extent than amoxicillin

Mechanosignaling in Bone Health, Trauma and Inflammation

SIGNIFICANCE: Mechanosignaling is vital for maintaining the structural integrity of bone under physiologic conditions. These signals activate and suppress multiple signaling cascades regulating bone formation and resorption. Understanding these pathways is of prime importance to exploit their therapeutic potential in disorders associated with bone loss due to disuse, trauma, or disruption of homeostatic mechanisms. RECENT ADVANCES: In the case of cells of the bone, an impressive amount of data has been generated that provides evidence of a complex mechanism by which mechanical signals can maintain or disrupt cellular homeostasis by driving transcriptional regulation of growth factors, matrix proteins and inflammatory mediators in health and inflammation. Mechanical signals act on cells in a magnitude dependent manner to induce bone deposition or resorption. During health, physiological levels of these signals are essential for maintaining bone strength and architecture, whereas during inflammation, similar signals can curb inflammation by suppressing the nuclear factor kappa B (NF-κB) signaling cascade, while upregulating matrix synthesis via mothers against decapentaplegic homolog and/or Wnt signaling cascades. Contrarily, excessive mechanical forces can induce inflammation via activation of the NF-κB signaling cascade. CRITICAL ISSUES: Given the osteogenic potential of mechanical signals, it is imperative to exploit their therapeutic efficacy for the treatment of bone disorders. Here we review select signaling pathways and mediators stimulated by mechanical signals to modulate the strength and integrity of the bone. FUTURE DIRECTIONS: Understanding the mechanisms of mechanotransduction and its effects on bone lay the groundwork for development of nonpharmacologic mechanostimulatory approaches for osteodegenerative diseases and optimal bone health