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  • Küçük Resim
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    Acid Tolerance Responce Of Cariogenic Microorganisms And Malolactic Fermentation
    (Cumhuriyet University Faculty of Dentistry, 2017) Keskin, Erol; Bağlar, Serdar; Örün, Tahir
    Dental caries is an infectious disease which occurs by the metabolism of bacteria acids released to dental enviroment which results hard tissue resolutions. Becouse of the oxygen-free structures of mature plaques complex and deep layers,cariojenic bacteries which have the ability of fermentation come forward. Strong acids like lactic acid, formic acid and pürivat deminish ph of the plaque and the acidty of the plaque causes demineralization of enamel during caries evolution. Existed plaque acidification is not only causes losing minerals from enamel but also threats microorganisms living in the biofilm of the plaque. So most of the microorganisms can’t survive under the ph value of 2.5. The ability of bacteria to survive in this acidic environment depends on the acid tolerance responses they have. Protection against acidity is possible by the production of glicoses,lactic acid and ATP(Adenosine triphosphate) by bacteries. Malolactic fermentation is the most important system that provides these productions in acidic environment. In order to better understand the anti-caries treatment protocols used in current preventive dental practice, the role of bacteria in the fermentation process needs to be known. İn this review we examined: chemical reactions of fermentation, which acids has been occured by the result of these reactions, ph changes in dental plaque, acidojenic and aciduric properties of bacteries which realise fermentation, how can microorganisms survive in acidic environment, what are the advantages propable inhibition of acid tolerance responces for guest. So we tried to attract attention to the anti-cariojenic strategies such as flour, chitosan, ?-mangostin and gene studies which are used in the inhibition of acid tolerance systems of bacteria © 2017. Cumhuriyet Dental Journal. All Rights Reserved.
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    Discoloration effects of traditional turkish beverages on different composite restoratives
    (Jaypee Brothers Medical Publishers (P) Ltd, 2017) Bağlar, Serdar; Keskin, Erol; Orun, Tahir; Es, Abdulhamit
    Aim: The aim of this study was to evaluate the discoloring effects of five beverages including, especially, traditional Turkish ones on five commonly used dental composites by using a spectrophotometer device. Materials and methods: Five methacrylate-based composites (shade A2) were selected to evaluate their color stability (175 disk samples). Four of them (Filtek Ultimate Universal, Clearfil Majesty ES-2, Tetric EvoCeram, and Cavex Quadrant Universal LC) were nanofilled universal composites for both anterior and posterior restorations, and one (Clearfil Majesty Posterior) was nano-superfilled for posterior restorations. The tested beverages were tamarind syrup, ottoman syrup, turnip juice, pomegranate juice, and distilled water (control). All samples were kept in an incubator at 37°C for 12 days (measured at 3rd, 6th, 12th day intervals) in immersion solutions which was equivalent to 1 year in vivo. Color measurements were made with VITA Easyshade Advance (Vident, Brea, CA) spectrophotometer device according to CIE L*a*b* system. Statistical analysis was performed with analysis of variance and least significant difference test to analyze differences in L*a*b* and ?E values. Results: All materials showed significant discoloration (p < 0.05) when compared with the control group. The highest ?E was observed in turnip juice, whereas ottoman syrup had the lowest ?E. Tetric EvoCeram showed the lowest ?E, while Clearfil Majesty ES-2 showed the highest ?E. Conclusion: In all the groups tested, clinically unacceptable ?E values were obtained. Although color stability of methacrylatebased composites has been widely investigated, this has not been done before with these kinds of immersion solutions. Clinical significance: Potential discoloration might be limited by dietary adjustments based on in vitro evaluations.
  • Küçük Resim
    Öğe
    Karyojen Mikroorganizmaların Asit Tolerans Yetenekleri ve Malolaktik Fermantasyon
    (2017) Keskin, Erol; Bağlar, Serdar; Örün, Tahir
    Diş çürüğü karyojen bakterilerin metabolizmaları sonucu ortama saldıkları asitler nedeniyle diş sert dokularında mineral çözünmesi sonucu oluşan bir çeşit enfeksiyon hastalığıdır. Olgunlaşmış plağın komplike ve derin tabakalardaki oksijensiz yapıdan dolayı çürük oluşumunda fermantasyon yapabilme yeteneği olan bakteriler ön plana çıkmaktadır. Fermantasyon sonucu açığa çıkan laktik asit, formik asit ve pirüvik asit gibi güçlü asitler, plak pH'sını düşürür ve oluşan plak asiditesi çürük gelişimi süresince minenin demineralizasyonuna yol açar. Oluşan plak asidifikasyonu sadece minenin mineral kaybına neden olmakla kalmaz aynı zamanda plak biyofilminin içerisinde yaşayan mikroorganizmalar için de tehlike oluşturur. Yani çoğu mikroorganizmalar, ölümcül pH değerleri olan pH 2.5 ve altında hayatlarını sürdüremezler. Bakterilerin bu asidik ortamda hayatta kalabilmeleri, sahip oldukları asit tolerans cevaplarına bağlıdır. Bakterilerin bu asiditeye karşı koyması glikoliz, laktik asit üretimi ve ATP(Adenozin trifosfat) üretimi sayesinde olur. Malolaktik fermantasyon ise asidik ortamda bu üretimleri sağlayan en önemli sistemdir. Güncel koruyucu diş hekimliği uygulamalarında kullanılan çürük önleyici tedavi protokollerinin daha iyi anlaşılması için bakterilerin fermantasyon sürecindeki rollerinin bilinmesi gerekmektedir. Bu derlemede fermantasyon sürecinin kimyasal tepkimelerini, bu tepkimeler sonucu hangi asitlerin oluştuğunu, dental plaktaki pH değişikliklerini, fermantasyonu gerçekleştiren bakterilerin asidojenik&asidürik özelliklerini mikroorganizmaların hayatlarını nasıl sürdürebildiklerini ayrıca asit tolerans cevabının muhtemel inhibisyonunun konak için ne tür avantajlar oluşturabileceği incelenmiştir. Böylece bakterilerin asit tolerans sistemlerinin inhibisyonunda kullanılan flor, çitosan, ?-mangostin ve gen çalışmaları gibi antikaryojenik stratejilere dikkat çekilmeye çalışılmıştır.