The Effect of Platelet-Rich Fibrin (PRF), Plasma Rich in Growth Factors (PRGF), and Enamel Matrix Proteins (Emdogain) on Migration of Human Gingival Fibroblasts.

STATEMENT OF THE PROBLEM: Platelet preparations such as plasma rich in growth factors (PRGF), platelet-rich fibrin (PRF), or enamel matrix proteins (Emdogain) are commonly used for soft and hard tissue regeneration. However, their comparative effectiveness has not been extensively studied, and a consensus has yet to be reached on their efficacy. PURPOSE: The aim of this in vitro study was to compare the effect of PRF, PRGF, and Emdogain on the proliferation of human gingival fibroblasts (HGF). MATERIALS AND METHOD: Artificial wounds were made in HGF cell culture after the fibroblasts reached nearly 100% of confluence. The study groups included leukocyte and platelet-rich fibrin (LPRF), pure platelet-rich fibrin (PPRF), PRGF and Emdogain. Stained cells were photographed at 48 h and one week and the percent of wound filling was measured. Statistical analysis was performed by one-way ANOVA and p values < 0.05 were considered statistically significant. RESULTS: The highest wound filling percentages at both time intervals were observed in the PPRF group, followed by the PRGF. The lowest percentage of wound healing among test groups was observed in the LPRF while Emdogain yielded modest results. However, statistical analysis showed similar wound healing values in PRGF, PPRF, and Emdogain groups. CONCLUSION: Within the limitations of this study, PRGF, PPRF, and Emdogain were similarly effective in enhancing the fibroblast proliferation and artificial wound closure.

In Vitro Comparison of Microbial Leakage of the Implant-Healing Abutment Interface in Four Connection Systems.

This study sought to assess microbial leakage through the implant-healing abutment interface in 4 dental implant connection systems. Ten implants of each of the 3i (double hexagon + flat to flat; group 1), IDI (internal hexagon + Morse taper; group 2), Swiss Plus (external bevel + internal octagon; group 3), and Tapered Screw-Vent (internal bevel + internal hexagon; group 4) systems were used in this in vitro, experimental study. Healing abutments were screwed to the implants with 10 Ncm torque. Implants were immersed in Escherichia coli suspension for 24 hours. Samples were taken of the internal surface of implants and cultured. The number of grown colonies was counted after 24 hours of culture and after 7 and 14 days of immersion in microbial suspension. The same was repeated with healing abutments torqued to 10 and 20 Ncm. With 10 Ncm torque, all specimens in all groups showed microleakage at one day with the highest microleakage in one sample in group 3. At 7 days, the highest microleakage was noted in one specimen in group 2. With 20 Ncm torque, group 3 showed significantly higher microleakage than other groups at 1 and 7 days (P < .05). Increasing the torque decreased microleakage in all groups except for group 3. Microbial leakage occurred in almost all implant systems in our study. In one-stage implant placement, healing abutments should be preferably torqued to 20 Ncm to minimize microleakage. Optimal torque for healing abutment insertion should be analyzed individually for each system.

Comparison of Stress and Strain Distribution Around Splinted and Nonsplinted 6-mm Short Implants in Posterior Mandible: A Finite Element Analysis Study.

PURPOSE: This study was designed to compare the biomechanical performance of splinted and nonsplinted short implants, in the posterior mandible, using finite element analysis. MATERIALS AND METHODS: Three-dimensional models of short implants with 2 different diameters (4 × 6 mm or 5 × 6 mm) were scanned, and CATIA (R21) was used to simulate the model of an edentulous lower jaw. Experimental groups were designed as follows: (1) D4L6-splinted (three 4 × 6-mm splinted implants), (2) D4L6-nonsplinted, (3) D5L6-splinted, and (4) D5L6-nonsplinted. A 100 N load was applied, and stress and strain values in surrounding bone were analyzed in specific nodes using ANSYS software (16.1). RESULTS: The maximum stress values under axial load were found in D5L6-splinted model, and under oblique load, D5L6-nonsplinted model had the maximum stress values. Under axial load, D4L6-splinted model showed maximum strain values, but when oblique load was applied, D4L6-nonsplinted model had the maximum strain values. CONCLUSION: Splinting adjacent short implants may provide less bone strain and stress, especially at the presence of lateral forces. Increasing the implant diameter may be effective in strain reduction, but does not seem to reduce the bone stress, regardless of the direction of the load applied.

The Effect of Photodynamic Therapy in the Treatment of Chronic Periodontitis: A Review of Literature.

Introduction: Chronic periodontitis is the most common periodontal disease which is related to the chronic accumulation of bacterial plaque. Since mechanical methods are not sufficient in the treatment of this disease, administration of local/systemic antibiotic is recommended following mechanical debridement. However, side effects of antibiotics such as microbial resistance and patient allergy led to development of alternative methods. One of these suggested methods is the antimicrobial photodynamic therapy (aPDT). PDT is a local noninvasive treatment modality without the side effects caused by antibiotics. The aim of this study was to review the articles related to the application of PDT with laser in the treatment of chronic periodontitis. Review of literature: In the present review of literature, the authors used key words such as chronic periodontitis, laser and photodynamic therapy, and conducted a literature search via Google Scholar and PubMed for the period of 1990 to 2015. A total of 47 articles in English were found. The articles that were not associated with the topic of research and review articles were deleted and only clinical trials were evaluated. After reviewing 23 articles' abstracts, the full texts of 16 articles were analyzed. Conclusion: Considering the safety, the lack of side effects and general advantages like more patient compliance, the PDT treatment with scaling and root planing (SRP) is recommended as an efficient adjunctive modality for the treatment of localized chronic periodontitis especially during the maintenance phase in non-surgical treatment.

Comparison of Er:YAG Laser and Hand Instrumentation on the Attachment of Cultured Human Gingival Fibroblasts to Periodontally Involved Root Surfaces.

Introduction: The present study compared the effects of erbium-doped yttrium aluminium garnet (Er:YAG) laser and hand instrumentation on the attachment of human gingival fibroblast (HGF) cells to periodontally involved root surfaces. Methods: A total of 40 tooth specimens were collected and treated in four distinct groups: scaled and root planed with hand instruments, scaled with Er:YAG laser, treated with a combination of hand instruments and Er:YAG laser and non-treated control group. The attachment and proliferation rate of HGF were assessed using MTT assay and scanning electron microscope (SEM) examination was used for cell morphological evaluation. Results: The MTT (3-[4, 5-dimethylthiazol-2-yl]-2, 5 diphenyl tetrazolium bromide) assay showed significant decrease in HGF cell viability in both hand instruments only and combination treated teeth specimens compared to control specimens (P<0.05), 24 hours after cell seeding. However, at time 48, the cell viability of attached cells in these 2 treated groups was almost similar to control. In contrast, at 24 and 48 hours after cell seeding, viability of attached cells was higher than control in Er:YAG laser treated only specimens (P<0.05). According to SEM study, the laser treated specimens showed more surface roughness. Conclusion: Er:YAG laser increased attachment and proliferation of HGF cells in comparison to the hand instruments method.

Lack of Altered BECN1 Gene Expression in Iranian Patients with Acute Myeloid Leukemia

Acute myeloid leukemia (AML), one of the most prevalent leukemia types in adults, demonstrates great heterogeneity in molecular and clinical terms. Hence, there is a necessity to the mechanisms involved in AML generation in order to determine optimal treatment. This cross sectional study aimed to assess changes in BECN1 gene expression in with blood samples from 30 AML patients, compared with samples from 15 healthy persons. RNA was extracted and cDNA was synthesized and Real Time PCR applied to determine BECN1 gene expression. The results showed no significant differences in BECN1 gene expression between patients with AML and normal controls (P > 0.05). It appears that expression of BECN1 does not play a significant role in genesis of AML leukemia.

Primary Malignant Melanoma of the Oral Cavity Around Dental Implants: Report of an Unusual Case.

INTRODUCTION: Primary oral melanoma is an uncommon malignant tumor that originates from the proliferation of melanocytes. CASE PRESENTATION: A 78-year-old man presented with a pigmented lesion around the maxillary anterior implant prosthesis. The lesion was excised and diagnosed as a melanoma. Biopsy showed a malignant pigmented neoplasm that included proliferation of dysplastic melanocytes into the superficial layers of the submucosa. Initial testing, including a positron emission tomography scan, showed no metastasis; however, after 7 months, the patient developed a cervical lymphadenopathy. A neck dissection was performed and indicated that there was metastasis of the primary melanoma. After surgery, the patient received chemotherapy. CONCLUSIONS: Histologic examination of the excised lesion revealed the presence of a malignant melanoma in association with a junctional nevus of the oral mucosa. The patient was referred to the oral and maxillofacial department for further evaluation.

Antibacterial effect of Iranian green-tea-containing mouthrinse vs chlorhexidine 0.2%: an in vitro study.

PURPOSE: Considering the antioxidant, anti-inflammatory and antimicrobial properties of green tea, this study aimed to evaluate the antibacterial effect of mouthrinses containing green tea extract vs 0.2% chlorhexidine on selected microorganisms in vitro. MATERIALS AND METHODS: The antibacterial activity of both mouthrinses and the pure green tea extract was assessed by using disk diffusion and the minimal inhibitory concentration (MIC) methods against five microorganisms: Streptococcus mutans, Streptococcus sanguis, Enterococcus faecalis, Pseudomonas aerogenosa and Escherichia coli. Growth inhibition zones were measured in mm after 24 h of incubation at 37°C. The two mouthrinses were assessed at concentrations of 1, 2, 4, 8, 16, 32, 64, 128, 256 and 512 mg/ml to determine the MIC, which was interpreted as the lowest concentration of the agent that completely inhibited the growth of the test species. RESULTS: 0.2% chlorhexidine produced a larger zone of growth inhibition than did the mouthrinse made of green tea extract (P < 0.01). Paradoxically, the growth inhibition zones of the tested bacteria were significantly larger in pure extract of green tea than in 0.2% chlorhexidine (P < 0.01). The chlorhexidine mouthrinse inhibited the growth of all tested species and exhibited significantly lower MICs than did the green tea mouthrinse (P < 0.01). CONCLUSIONS: Even though the mouthrinse made with green tea extract presented an in vitro antimicrobial activity inferior to 0.2% chlorhexidine, the pure extract had considerable bactericidal effect.