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  • Research Summaries in Focus


    Summarized & Presented by:


    Mohammad Adnan Abu Khalifeh BDS

    Assistant Editor, Smile Dental Journal

    e-communication Committee Vice President, JDA

    Health Editor, UMEN MAGAZINE

    Co-Owner, Dental Lounge/Smile Studio,

     Amman – Jordan | harper2003@gmail.com


    Comparative Evaluation of Human Pulp Tissuxe Dissolution by Different Concentrations of Chlorine Dioxide, Calcium Hypochlorite and Sodium Hypochlorite: An In Vitro Study


    Taneja S, Mishra N, Malik S

    J Conserv Dent. 2014 Nov;17(6):541-5




    Irrigation plays an indispensable role in removal of tissue remnants and debris from the complicated root canal system. This study compared the human pulp tissue dissolution by different concentrations of chlorine dioxide, calcium hypochlorite and sodium hypochlorite.



    Pulp tissue was standardized to a weight of 9mg for each sample. In all, 60 samples obtained were divided into 6 groups according to the irrigating solution used- 2.5% sodium hypochlorite (NaOCl), 5.25% NaOCl, 5% calcium hypochlorite (Ca(OCl)2), 10% Ca(OCl)2, 5%chlorine dioxide (ClO2) and 13% ClO2. Pulp tissue was placed in each test tube carrying irrigants of measured volume (5ml) according to their specified subgroup time interval: 30 minutes (Subgroup A) and 60 minutes (Subgroup B). The solution from each sample test tube was filtered and was left for drying overnight. The residual weight was calculated by filtration method.



    Mean tissue dissolution increases with increase in time period. Results showed 5.25% NaOCl to be most effective at both time intervals followed by 2.5% NaOCl at 60 minutes, 10%Ca(OCl)2 and 13% ClO2 at 60 minutes. Least amount of tissue dissolving ability was demonstrated by 5% Ca(OCl)2 and 5% ClO2 at 30 minutes. Distilled water showed no pulp tissue dissolution.



    Withinthe limitations of the study, NaOCl most efficiently dissolved the pulp tissue at both concentrations and at both time intervals. Mean tissue dissolution by Ca(OCl)2 and ClO2 gradually increased with time and with their increase in concentration.


    Root Coverage Using Subepithelial Connective Tissue Graft with Platelet-Rich Plasma in the Treatment of Gingival Recession: A Clinical Study


    Srinivas, Rupa, Halini Kumari, Prasad, Varalakshmi, Sudhakar

    J Pharm Bioallied Sci. 2015 Aug;7(Suppl 2):S530-8




    The presence of gingival recession associated with an insufficient amount of keratinized tissue may indicate gingival augmentation procedure. It is a multifaceted problem for which several treatment options are available. The most predictable technique used for gingival augmentation is the subepithelial connective tissue graft (SCTG). Platelet-rich plasma (PRP) is an enhanced source of growth factors and helps in accelerated periodontal repair and regeneration.



    The aim of this study was to evaluate the efficacy of SCTG along with PRP in the treatment of Miller’s class I and II gingival recessions.



    Eleven subjects with Miller’s class I and II gingival recessions were treated using SCTG with PRP. Clinical variables, including plaque index, gingival index, recession depth (RD), Recession width (RW), width of the keratinized gingiva, probing pocket depth (PD) and clinical attachment level (CAL) were recorded. Patients were recalled at baseline, 3 months, 6 months and 1-year after surgery and clinical recordings were taken. Root coverage percentage (%) was measured at the end of 1-year.



    The clinical parameters were analyzed during the follow-up period by repeated measures ANOVA test. Twelve months follow-up results showed significant improvements in all the clinical parameters. Reduction of recession resulted in a significant decrease in CAL, PD, RW and RD at the end of 12 months. A statistically significant gain in width of keratinized gingiva and a mean root coverage of 84.72 ± 19.10 was obtained at the end of 12 months.



    From the results of this study, it may be concluded that SCTG with PRP is an effective and predictable method to treat miller’s class I and II gingival recession.



    Physico-mechanical Characteristics of Commercially Available Bulk-fill Composites


    Leprince JG, Palin WM, Vanacker J, Sabbagh J, Devaux J, Leloup G

    J Dent. 2014 Aug;42(8):993-1000



    Bulk-fill composites have emerged, arguably, as a new “class” of resin-based composites, which are claimed to enable restoration in thick layers, up to 4mm. The objective of this work was to compare, under optimal curing conditions, the physico-mechanical properties of most currently available bulk-fill composites to those of two conventional composite materials chosen as references, one highly filled and one flowable “nano-hybrid” composite.



    Tetric EvoCeram Bulk Fill (Ivoclar-Vivadent), Venus Bulk Fill (Heraeus-Kulzer), SDR (Dentsply), X-tra Fil (VOCO), X-tra Base (VOCO), Sonic Fill (Kerr), Filtek Bulk Fill (3M-Espe), Xenius (GC) were compared to the two reference materials. The materials were light-cured for 40s in a 2mm×2mm×25mm Teflon mould. Degree of conversion was measured by Raman spectroscopy, Elastic modulus and flexural strength were evaluated by three point bending, surface hardness using Vickers microindentation before and after 24h ethanol storage, and filler weight content by thermogravimetric analysis. The ratio of surface hardness before and after ethanol storage was considered as an evaluation of polymer softening. Data were analyzed by one-way ANOVA and post hoc Tukey’s test (p=0.05).



    The mechanical properties of the bulk-fill composites were mostly lower compared with the conventional high viscosity material, and, at best, comparable to the conventional flowable composite. Linear correlations of the mechanical properties investigated were poor with degree of conversion (0.090.8). Softening in ethanol revealed differences in polymer network density between material types.



    The reduction of time and improvement of convenience associated with bulk-fill materials is a clear advantage of this particular material class. However, a compromise with mechanical properties compared with more conventional commercially-available nano-hybrid materials was demonstrated by the present work.



    Given the lower mechanical properties of most bulk-fill materials compared to a highly filled nano-hybrid composite, their use for restorations under high occlusal load is subject to caution. Further, the swelling behaviour of some of the bulk-fill materials may be a reason for concern, which highlights the critical requirement for a veneering material, not only to improve aesthetic quality of the translucent material, but to reduce the impact of degradation.