Fractional carbon dioxide laser combined with intradermal injection of autologous platelet-rich plasma versus noncross-linked hyaluronic acid in the treatment of atrophic postacne scars: A split face study.

BACKGROUND: Atrophic acne scarring is a common cosmetic problem that may affect 95% of patients with acne. AIMS: The objective is to evaluate the efficacy of the fractional CO2 laser combined with intradermal injection of PRP versus intradermal injection of noncross-linked hyaluronic acid in the treatment of different types of atrophic postacne scars. METHODS: The study included 30 patients with postacne scars. All the patients received 3 treatments of fractional CO2 laser combined with intradermal injection of PRP at one side of the face compared with intradermal injection of noncross-linked hyaluronic acid at the other side of the face. Efficacy of the treatment was assessed by the physician's clinical assessment using Goodman and Baron's qualitative and quantitative grading systems and histopathological evaluation from six participants. RESULTS: The study included 30 patients ages ranging from 25 to 44 years old. There was a statistically significant reduction in the severity of acne scars on both sides after treatment using qualitative and quantitative Goodman and Baron. Histopathological evaluation showed an increase in the collagen and elastic fiber content in both modalities with a more favorable outcome in the PRP-treated side. CONCLUSION: Both treatment modalities resulted in a significant clinical and histopathological improvement in atrophic postacne scar with insignificant difference between them.

Evaluation of stresses developed in different bracket-cement-enamel systems using finite element analysis with in vitro bond strength tests.

BACKGROUND: The purpose of this study was to determine the bond strength of different orthodontic bracket materials (ceramic, stainless steel, and titanium) as well as stresses developed in bracket-cement-enamel systems using finite element (FE) analysis. METHODS: One hundred and thirty-five extracted human caries-free upper central incisors were divided into three groups (n = 45/group) according to the type of orthodontic bracket materials (stainless steel, ceramic, and titanium). Each group was further subdivided into three subgroups (n = 15/group) according to the bond strength test loading mode (shear short side, shear long side, and tensile). After debonding, the fractured specimen was examined, and the adhesive remnant index (ARI) was determined. FE analysis models analyzed the stress distribution within the cement and enamel. Bond strengths were analyzed using ANOVA and Tukey's test, and the ARI scores were analyzed using chi-square (χ2) test. RESULTS: Shear loading at the short side of the bracket resulted in the highest bond strength and lowest maximum principal stress both on cement and enamel compared with the other loading modes (P < 0.05). Ceramic brackets presented with higher bond strength and lower maximum principal stress than metallic brackets (P < 0.05). There was a significant difference for ARI scores between the type of brackets (χ2 = 64.852, P < 0.001). CONCLUSION: The findings suggest that the manner of loading orthodontic brackets and the selection of orthodontic bracket materials affect the bond strength and stresses developed both on cement and enamel.

New approach of bone marrow-derived mesenchymal stem cells and human amniotic epithelial cells applications in accelerating wound healing of irradiated albino rats.

BACKGROUND AND OBJECTIVES: Irradiated wound healing is a highly complex and dynamic process. The latest technology making a huge difference in this process is stem cell therapy. The goal of this study was to evaluate the use of bone marrow-derived mesenchymal stem cells (BM-MSCs) or human amniotic epithelial cells (HAECs) in the healing of irradiated wounds. METHODS AND RESULTS: Forty five male albino rats were subjected to whole body 6 gray gamma radiations. One day post irradiation, full-thickness incisional wound was created in the tibial skin. The rats were randomly equally divided into three groups. The incisions of the first group (gp I) were injected intra-dermally with saline before stitching and those of both the second (gp II) and the third groups (gp III) were intradermally injected with BM-MSCs and HAECs before stitching respectively. Animals were sacrificed after the third, seventh and fourteenth days postoperative. The healing process was assessed histopathologically. CXCL-5, SDF-1 and Transforming growth factor-beta 1 (TGF-ß1) expression were also detected in biopsies from all wounds. Expression of TGF-ß1 in gp I was more than the other groups leading to severe inflammation, deficient healed dermis and delayed reepithelialization. SDF-1 expression was high in gp II while CXCL-5 expression was high in gp III causing accelerated wound healing. BM-MSCs showed a great effect on the quality of the dermis, while superiority of the epithelium and its appendages were achieved in HAECs group. CONCLUSIONS: Using BM-MSCs and HAECs could be used safely in case of irradiated wounds.