Satheesh Elangovan

Effect of Alveolar Ridge Preservation after Tooth Extraction A Systematic Review and Meta-analysis

Alveolar ridge preservation strategies are indicated to minimize the loss of ridge volume that typically follows tooth extraction. The aim of this systematic review was to determine the effect that socket filling with a bone grafting material has on the prevention of postextraction alveolar ridge volume loss as compared with tooth extraction alone in nonmolar teeth. Five electronic databases were searched to identify randomized clinical trials that fulfilled the eligibility criteria. Literature screening and article selection were conducted by 3 independent reviewers, while data extraction was performed by 2 independent reviewers. Outcome measures were mean horizontal ridge changes (buccolingual) and vertical ridge changes (midbuccal, midlingual, mesial, and distal). The influence of several variables of interest (i.e., flap elevation, membrane usage, and type of bone substitute employed) on the outcomes of ridge preservation therapy was explored via subgroup analyses. We found that alveolar ridge preservation is effective in limiting physiologic ridge reduction as compared with tooth extraction alone. The clinical magnitude of the effect was 1.89 mm (95% confidence interval [CI]: 1.41, 2.36; p < .001) in terms of buccolingual width, 2.07 mm (95% CI: 1.03, 3.12; p < .001) for midbuccal height, 1.18 mm (95% CI: 0.17, 2.19; p = .022) for midlingual height, 0.48 mm (95% CI: 0.18, 0.79; p = .002) for mesial height, and 0.24 mm (95% CI: –0.05, 0.53; p = .102) for distal height changes. Subgroup analyses revealed that flap elevation, the usage of a membrane, and the application of a xenograft or an allograft are associated with superior outcomes, particularly on midbuccal and midlingual height preservation.

The enhancement of bone regeneration by gene activated matrix encoding for platelet derived growth factor

Gene therapy using non-viral vectors that are safe and efficient in transfecting target cells is an effective approach to overcome the shortcomings of protein delivery of growth factors. The objective of this study was to develop and test a non-viral gene delivery system for bone regeneration utilizing a collagen scaffold to deliver polyethylenimine (PEI)-plasmid DNA (pDNA) [encoding platelet derived growth factor-B (PDGF-B)] complexes. The PEI-pPDGF-B complexes were fabricated at amine (N) to phosphate (P) ratio of 10 and characterized for size, surface charge, and in vitro cytotoxicity and transfection efficacy in human bone marrow stromal cells (BMSCs). The influence of the complex-loaded collagen scaffold on cellular attachment and recruitment was evaluated in vitro using microscopy techniques. The in vivo regenerative capacity of the gene delivery system was assessed in 5 mm diameter critical-sized calvarial defects in Fisher 344 rats. The complexes were ~100 nm in size with a positive surface charge. Complexes prepared at an N/P ratio of 10 displayed low cytotoxicity as assessed by a cell viability assay. Confocal microscopy revealed significant proliferation of BMSCs on complex-loaded collagen scaffolds compared to empty scaffolds. In vivo studies showed significantly higher new bone volume/total volume (BV/TV) % in calvarial defects treated with the complex-activated scaffolds following 4 weeks of implantation (14- and 44-fold higher) when compared to empty defects or empty scaffolds, respectively. Together, these findings suggest that non-viral PDGF-B gene-activated scaffolds are effective for bone regeneration and are an attractive gene delivery system with significant potential for clinical translation.

Nano-sized calcium phosphate particles for periodontal gene therapy.

BACKGROUND Growth factors such as platelet-derived growth factor (PDGF) have significantly enhanced periodontal therapy outcomes with a high degree of variability, mostly due to the lack of continual supply for a required period of time. One method to overcome this barrier is gene therapy. The aim of this in vitro study is to evaluate PDGF-B gene delivery in fibroblasts using nano-sized calcium phosphate particles (NCaPP) as vectors. METHODS NCaPP incorporating green fluorescent protein (NCaPP-GFP) and PDGF-B (NCaPP-PDGF-B) plasmids were synthesized using an established precipitation system and characterized using transmission electron microscopy and 1.2% agarose gel electrophoresis. Biocompatibility and transfection of the nanoplexes in fibroblasts were evaluated using cytotoxicity assay and florescence microscopy, respectively. Polymerase chain reaction and enzyme-linked immunosorbent assay were performed to evaluate PDGF-B transfection after different time points of treatments, and the functionality of PDGF-B transfection was evaluated using the cell proliferation assay. RESULTS Synthesized NCaPP nanoplexes incorporating the genes of GFP and PDGF-B were spherical in shape and measured about 30 to 50 nm in diameter. Gel electrophoresis confirmed DNA incorporation and stability within the nanoplexes, and 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium reagent assay demonstrated their biocompatibility in fibroblasts. In vitro transfection studies revealed a higher and longer lasting transfection after NCaPP-PDGF-B treatment, which lasted up to 96 hours. Significantly enhanced fibroblast proliferation observed in NCaPP-PDGF-B-treated cells confirmed the functionality of these nanoplexes. CONCLUSION NCaPP demonstrated higher levels of biocompatibility and efficiently transfected PDGF plasmids into fibroblasts under described in vitro conditions.

Chemically modified RNA activated matrices enhance bone regeneration

There exists a dire need for improved therapeutics to achieve predictable bone regeneration. Gene therapy using non-viral vectors that are safe and efficient at transfecting target cells is a promising approach to overcoming the drawbacks of protein delivery of growth factors. Here, we investigated the transfection efficiency, cytotoxicity, osteogenic potential and in vivo bone regenerative capacity of chemically modified ribonucleic acid (cmRNA) (encoding BMP-2) complexed with polyethylenimine (PEI) and made comparisons with PEI complexed with conventional plasmid DNA (encoding BMP-2). The polyplexes were fabricated at an amine (N) to phosphate (P) ratio of 10 and characterized for transfection efficiency using human bone marrow stromal cells (BMSCs). The osteogenic potential of BMSCs treated with these polyplexes was validated by determining the expression of bone-specific genes, osteocalcin and alkaline phosphatase as well as through the detection of bone matrix deposition. Using a calvarial bone defect model in rats, it was shown that PEI-cmRNA (encoding BMP-2)-activated matrices promoted significantly enhanced bone regeneration compared to PEI-plasmid DNA (BMP-2)-activated matrices. Our proof of concept study suggests that scaffolds loaded with non-viral vectors harboring cmRNA encoding osteogenic proteins may be a powerful tool for stimulating bone regeneration with significant potential for clinical translation.

Outcomes in Patients Hospitalized for Periapical Abscess in the United States

BACKGROUND. Severe infections resulting from periapical abscesses may warrant hospitalization. The authors conducted a study to investigate the factors affecting outcomes for patients hospitalized for periapical abscess in the United States in 2007. METHODS. The authors used the Nationwide Inpatient Sample of the Healthcare Cost and Utilization Project for 2007. They selected for analysis all hospitalizations attributed primarily to periapical abscess. Outcomes examined included hospitalization charges, length of stay and type of admission (emergency or urgent versus elective). They used multivariable regression analysis to examine the effects of patient-related factors (including age, sex, presence of comorbid conditions, insurance status, type of periapical abscess and discharge disposition) on outcomes. RESULTS. In 2007, 7,886 hospitalizations were attributed primarily to periapical abscess. Total hospital charges were

Quality Assessment of Systematic Reviews on Periodontal Regeneration in Humans

105.8 million. Periapical abscess also resulted in a total of 23,001 hospitalization days. The mean hospitalization charges and length of stay were

Prevalence and impact of complications on outcomes in patients hospitalized for oral and oropharyngeal cancer treatment

13,590 and 2.92 days, respectively. The authors found an association between patients with comorbid conditions and higher charges and longer length of stay (P < .05). Of all hospitalizations, 91 percent occurred on an emergency or urgent basis. The percentage was significantly higher among uninsured patients than among those with private insurance (P < .05). CONCLUSION. The study provides nationally representative estimates of outcomes associated with hospitalizations due to periapical abscess, and it highlights the substantial resources needed to treat patients hospitalized for this condition.

Incorporation of copper into chitosan scaffolds promotes bone regeneration in rat calvarial defects

BACKGROUND Systematic reviews represent the highest form of evidence in the current hierarchy of evidence-based dentistry. Critical analysis of published systematic reviews may help to analyze their strengths and weaknesses and to identify areas that need future improvement. The aim of this overview is to determine and compare the quality of systematic reviews published in the field of periodontal regeneration using established checklists, such as the Assessment of Multiple Systematic Reviews (AMSTAR) guidelines. METHODS A systematic search was conducted to retrieve reviews on periodontal regeneration in humans. A total of 14 systematic reviews were selected using a set of inclusion and exclusion criteria. Two independent reviewers appraised the quality of the selected reviews using AMSTAR guidelines. Each article was given an AMSTAR total score, based on the number of AMSTAR criteria that were fulfilled. The quality of included reviews was further assessed using a checklist proposed in 2003. RESULTS Only one of the selected systematic reviews satisfied all the AMSTAR guidelines, whereas two reviews satisfied just two of the 11 items. This study shows that published systematic reviews on periodontal regeneration exhibit significant structural and methodologic variability. Quality assessment using the additional checklist further confirmed the variability in the way systematic reviews were conducted and/or reported. CONCLUSION Consideration of guidelines for quality assessment, such as AMSTAR, when designing and conducting systematic reviews may increase the validity and clinical applicability of future reviews.

Outcomes in Patients Visiting Hospital Emergency Departments in the United States Because of Periodontal Conditions

OBJECTIVE We studied the association between presence of complications and hospitalization outcomes, including hospital charges, length of stay in hospital, and in-hospital mortality. METHODS The Nationwide Inpatient Sample for 2008 was used. All hospital discharges with a primary diagnosis of oral and oropharyngeal cancers were selected. Presence of complications was determined by using ICD-9-CM codes. The association between the presence of complications and outcomes (hospital charges, length of stay, and in-hospital mortality) was examined by multivariable linear and multivariable logistic regression analyses. The effects of several patient- and hospital-related confounders were adjusted in the regression analyses. RESULTS A total of 17,632 hospitalizations were attributed to oral and oropharyngeal cancers. A total of 519 (2.9%) patients died in the hospitals. The total hospitalization charges were close to

Nanoplex-Mediated Codelivery of Fibroblast Growth Factor and Bone Morphogenetic Protein Genes Promotes Osteogenesis in Human Adipocyte-Derived Mesenchymal Stem Cells

1.08 billion. Oral and oropharyngeal cancers accounted for 117,472 hospitalization days (mean length of stay 6.6 days). The overall complication rate was 14.95%. The most frequently present complication was hemorrhagic complications. Among the different complications, septicemia was associated with the worst outcomes. Patients with septicemia were associated with the highest odds for in-hospital mortality (OR = 13.06, 95% CI = 3.81-48.50, P = .0001). CONCLUSIONS Presence of complications was associated with poor outcomes, such as high in-hospital mortality rates, excess hospitalization charges, and longer length of stay in hospital. Among the different complications, septicemia was associated with the worst outcomes.