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.

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.

Prevalence of Porphyromonas gingivalis fimbriae A genotypes II and IV in patients with chronic periodontitis and atherosclerosis.

Background: Atherosclerosis is known as one of the chronic diseases with high prevalence in the human species. Many studies have elucidated the relationship between this disease and chronic periodontitis caused by Porphyromonas gingivalis (P.g). The aim of this study was to investigate the prevalence of P.g fimbriae A (fimA) genotypes II and IV in patients with periodontitis and atherosclerosis. Methods: This cross-sectional study investigated the frequency of P.g II and IV genotypes in the subgingival plaque specimens of 42 subjects in three experimental groups: periodontitis (A), atherosclerosis (B), periodontitis + atherosclerosis (C) and aortic wall specimens obtained from 30 patients (groups B and C) by the PCR technique. Results: P.g bacterium was seen in 46.6% of patients with chronic periodontitis. The same bacterium was not found in aortic wall specimens of patients with chronic periodontitis (group C) and there was only one P.g-positive aortic wall specimen (7.7%) among the patients with healthy periodontium (group B). Genotypes II and IV were not observed in any specimen. Conclusion: The results of statistical analysis showed no significant correlation between the prevalence of P.g and genotypes II and IV in the subgingival plaques and the incidence and severity of atherosclerosis.

Patterns of stress and strain in complete-arch prostheses supported by four or six implants: A literature review of finite element analyses.

Background: Tilted implants have been recommended as an alternative to the bone graft procedures in implant sites although with possibly higher stress concentrations. This study reviews finite element studies to evaluate patterns of stress and strain in complete-arch prostheses supported by 4‒6 implants. Methods: A literature search was performed using the online databases. Articles published in English from 2003 to 2015 were reviewed. A total of 100 articles were found related to the subject and after evaluating the titles and abstracts, 18 studies were selected. Results: By increasing the number of implants, a reduction was detected in the amount of stress in the bone and implants, while in others, the stress level did not change with the increase in the number of implants. Conclusion: According to finite element analyses, placing a distal implant in an angular position results in better distribution of forces and stresses. Using less cantilever lengths would reduce the stress.

Comparison of Attachment and Proliferation of Human Gingival Fibroblasts on Different Collagen Membranes.

BACKGROUND AND AIM: Human gingival fibroblasts cultured on collagen membrane as an alternative treatment method used in tissue regeneration can lead to improved results in root coverage. The aim of this study was to evaluate the human gingival fibroblast proliferation and adhesion cultured on three types of collagen membranes. MATERIALS AND METHODS: In this in vitro study, first-line human gingival fibroblast cells (HGF1-RT1) prepared and cultured on three membranes, including porcine pericardium (PP) (Jason, Botiss dental), human pericardium (HP) (Regen, Faravardeh Baft Iranian), and glutaraldehyde cross-linked (GC) (BioMend Extend, Zimmer Dental). Cell survival was assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) after 24, 48, and 72 h and 7 days. Furthermore, morphology and adhesion of cells on the membrane were evaluated after 1 and 7 days by electron microscopy (scanning electron microscopy [SEM]). Statistical analysis was performed using two-way ANOVA with a significance level of 0.05. RESULTS: Based on the results of MTT, cell survival on HP and PP membranes after 7 days significantly increased (P < 0.001), but for the GC membrane, it was reduced after 7 days (P = 0.031). Cell survival on HP and PP membranes did not differ (P = 1) and was more than GC (P < 0.001). SEM images showed that the adhesion of cells was better on HP and PP membranes than GC. CONCLUSION: The results of this study showed that natural collagen membranes (HP and PP) similarly support proliferation and adhesion of gingival fibroblasts. Survival and adhesion of gingival fibroblasts on cross-linked collagen membrane was less than two other membranes.

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.

Efficacy of Conventional Laser Irradiation Versus a New Method for Gingival Depigmentation (Sieve Method): A Clinical Trial.

Introduction: Diode laser irradiation has recently shown promising results for treatment of gingival pigmentation. This study sought to compare the efficacy of 2 diode laser irradiation protocols for treatment of gingival pigmentations, namely the conventional method and the sieve method. Methods: In this split-mouth clinical trial, 15 patients with gingival pigmentation were selected and their pigmentation intensity was determined using Dummett's oral pigmentation index (DOPI) in different dental regions. Diode laser (980 nm wavelength and 2 W power) was irradiated through a stipple pattern (sieve method) and conventionally in the other side of the mouth. Level of pain and satisfaction with the outcome (both patient and periodontist) were measured using a 0-10 visual analog scale (VAS) for both methods. Patients were followed up at 2 weeks, one month and 3 months. Pigmentation levels were compared using repeated measures of analysis of variance (ANOVA). The difference in level of pain and satisfaction between the 2 groups was analyzed by sample t test and general estimate equation model. Results: No significant differences were found regarding the reduction of pigmentation scores and pain and scores between the 2 groups. The difference in satisfaction with the results at the three time points was significant in both conventional and sieve methods in patients (P = 0.001) and periodontists (P = 0.015). Conclusion: Diode laser irradiation in both methods successfully eliminated gingival pigmentations. The sieve method was comparable to conventional technique, offering no additional advantage.

In Vitro Study of Er:YAG and Er, Cr:YSGG Laser Irradiation on Human Gingival Fibroblast Cell Line.

The ultimate goal of the periodontal treatments is a regeneration of periodontium. Recently, laser irradiations are commonly used to improve wound repair. Because of many controversies about the effects of laser on soft tissue regeneration, more in vitro studies are still needed. The aim of the present in vitro study was to compare the effects of different doses of Er:YAG (erbium-doped:yttrium, aluminum, garnet) and Er, Cr:YSGG (erbium, chromium-doped: yttrium, scandium, gallium, garnet) laser treatment on human gingival fibroblasts (HGF) proliferation. In this randomized single-blind controlled in vitro trial, HGF cells were irradiated using Er:YAG and Er, Cr:YSGG laser for 10 and 30 seconds or remained unexposed as a control group. After a culture period of 24 and 48 hours, HGF cell proliferation was evaluated by MTT assay. The data were subjected to one-sided analysis of variance and Tukey multiple comparison tests. Our results showed Er:YAG application for 10 and 30 seconds as well as Er, Cr:YSGG irradiation for 10 and 30 seconds induced statistically significant (P<0.05) proliferation of HGF cells as compared with the control at 24 hours up to 18.39%, 26.22%, 21.21%, and 17.06% respectively. In 48 hour incubations, Er:YAG and Er, Cr:YSGG irradiation for 10 and 30 seconds significantly increased cellular proliferation up to 22.9%, 32.24%, 30.52% and 30.02% respectively (P<0.05). This study demonstrates that Er:YAG and Er, Cr:YSGG laser significantly increased HGF cell proliferation compared to the control specimens. This higher proliferation can lead to increased wound repair in clinical conditions.

Gingival biotype: a review.

Among the factors that may impede success in dental treatments, gingival biotype is the greatest cause of concern, particularly affecting the outcomes of periodontal therapy, root coverage procedures, and implant placement. Different tissue biotypes respond differently to inflammation and to surgical and restorative treatment; consequently, it is crucial to identify tissue biotype before treatment. Special care must be taken when treatment planning for cases with a thin gingival biotype. This article reviews the characteristics of various gingival biotypes and the many ways to determine them.

Adjunctive effects of systemic amoxicillin and metronidazole with scaling and root planing: a randomized, placebo controlled clinical trial.

AIMS: The objective of this study was to investigate the effect of the systemic administration of metronidazole and amoxicillin as an adjunct to initial periodontal therapy in patients with moderate to severe chronic periodontitis. METHODS AND MATERIALS: This randomized, double blind, placebo controlled parallel study involved 50 adult patients with untreated periodontitis who were randomly assigned to receive either a full-mouth scaling and root planing along with systemic metronidazole and amoxicillin (T group) or scaling and root planing with a placebo (P group). Clinical measurements including probing depth (PD), clinical attachment levels (CAL), Plaque Index (PI), and Bleeding Index (BI) were recorded at baseline and six to eight weeks after therapy. The deepest pocket was selected and samples for microbiological testing were taken. Patients received coded study medications of either 500 mg amoxicillin in combination with 250 mg metronidazole or an identical placebo every eight hours for seven days following scaling and root planing. RESULTS: There was a significant change in PD (P=0.0001), CAL (P=0.00001), PI (P<0.05), and BI (P<0.05) in the T group compared to the placebo group after therapy. Parallel to the clinical changes, treatment significantly reduced the number of Actinobacillus actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), and P. intermedia (Pi) compared with baseline in the T group (P=0.003, 0.021 and 0.0001, respectively). However, in the P group only the Pi colony count was reduced significantly (P=0.0001). After therapy, there was a significant difference between the T and P groups in the number of patients negative for Aa, Pg, and Pi (Pv = 0.033). CONCLUSIONS: The significant differences between treatment and placebo groups are in line with other studies and support the considerable adjunctive benefits of the combination of amoxicillin and metronidazole in the treatment of chronic periodontitis.