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20 ◊Page 19 GENERAL DENTISTRY Dental Tribune Middle East & Africa Edition | 2/2017 acts against a wide spectrum of mi- croorganisms, including E. faecalis (Schäfer & Bössmann, 2005; Gomes et al., 2002) and Candida albicans (Ferguson et al., 2002). To act effec- tively against these microorganisms, CHX concentration must be at least 1%, and obtains better results at 2% (Sassone et al., 2003). In the present study, 2 % CHX reduced the CFU/mL count with statistically signifi cant difference in comparison with the positive control group but no signifi - cance in comparison with the other treatments assayed. But CHX, unlike NaOCL, has no capacity to dissolve remaining necrotic tissue (Naenni et al., 2004); for this reason, SEM results for CHX showed a percentage of area occupied by detritus that was lower than only the positive control group, although without statistically signif- icant differences in comparison with the other treatment groups. In this context, in order to reduce NaOCL concentration, it might be useful to combine the two irrigants to obtain a synergic antibacterial effect without losing NaOCL’s capacity to eliminate detritus (Flach et al., In press). The concept of “Lesion Sterilization and Tissue Repair” or “LSTR therapy” is based on a mixture of antibiotics used to disinfect pulp and periapical lesions (Hoshino & Takushige, 1998). TAM is made up of a biocompat- ible combination of three antibiot- ics: ciprofl oxacin, metronidazole and minocycline (Gomes-Filho et al., 2012). Adl et al. (Adl et al., 2012) showed that metronidazole is the most effective component against E. faecalis (due to its activity against a wide spectrum of anaerobic bac- teria and protozoa). Minocycline is bacteriostatic and has a wide range of activities against gram-positive and gram-negative bacteria through the prevention of protein synthesis by the organism, and cirpofl oxacin has a rapid bactericidal activity and is more effective against gram-neg- ative bacteria (Bazvand et al., 2014). The main disadvantages of TAM use in endodontics are the possible dete- rioration of the tooth caused by mi- nocycline (Hoshino et al., 1996) and possible bacterial resistance (Huang, 2008). In the present study, TAM ap- plication reduced the CFU/mL count with signifi cant difference in com- parison with the positive control group, but with no signifi cant differ- ences in comparison with the other treatments. E. faecalis is able to survive for long periods without nutrients; it invades dentinal tubules (where it may per- sist at depths of over 300 µm) (Peters et al., 2001), which protect it against the usual irrigating agents (Love et al., 2001). For this reason the pen- etration capacity of laser therapy or the bactericidal effect of ozone can reduce the failure rate in endodon- tic treatments. E. faecalis inside root canals could be reduced by 97.1% if treated with PDT alone for 30 sec- onds or by 99.9% if treated with NaOCL followed by PDT (also for 30 seconds) (Rios et al., 2011). In the pre- sent in vitro study, teeth treated with PDT obtained a CFU/mL count of 3.63 ± 1.61, which was similar to ozone (3.62 ± 0.92), showing statistically signifi cant differences in compari- son with the positive control group but not between the two groups. As in the present study, Cheng et al. (Cheng et al., 2012) used methylene blue as a photosensitizer (PS) fol- lowed by exposure to LED light at 660 nm for 60 seconds, obtaining a 98.13% reduction in human teeth infected by E. faecalis. As for ozone, most studies of ozone application in endodontics have focused on its antimicrobial activity. Nagayoshi et al. (Nagayoshi et al., 2004) found that ozonated water was highly ef- fective in killing both gram-positive and gram-negative microorganisms. Moreover, the antibacterial activity of gaseous ozone has been proved to be greater than even laser therapies such as Potassium titanyl phosphate (KTiOPO4), otherwise known as KTP laser (Kustarci et al., 2009). In conclusion, application of PDT, 2% CHX, TAP, propolis and ozone all showed antibacterial potential simi- lar al 2.5% NaOCL against endodontic infection by Enterococcus faecalis. Dr. Pablo Salmerón from Graduating Murcia University with a degree in Den- tistry, Dr. Pablo went in on to specialise Endodontology, be- coming profi cient in fi nest details of this specifi c subject – Dr. Pablo came to Dubai after working in the UK – where he has been working as an Endodontist, as well as spending time teaching his fi eld to keen dentistry students at the University of Manchester. Dr. Pablo has been working with Micro- scopes since 2009. “I am greatly pleased with the work I am able to perform at Dr. Roze & Associates Dental Clinic – whilst being to fulfi l my other passions in this fi eld, such as lectur- ing and public-speaking. Dubai also gives me a chance to play golf, run and travel to exciting locations across the globe.” Researchers fi nd new evidence of diet in ancient teeth By DTI LEIOA, Spain: Using dental samples, Spanish researchers have applied standard geological techniques and methods at an architectural site in the region of Saragossa to estab- lish the diet of a medieval Muslim community that lived in the region between the eighth and tenth cen- turies. The study has provided new insights into their diet and found that a few of them may have been poisoned by lead. The study was part of the doctoral thesis of geologist Iranzu Laura Guede on diet and mobility in the medieval period in the north of the Iberian Peninsula. It was conducted by a research group at the University of the Basque Country and analysed the diet of Muslim individuals in the community at the archaeological site at Tauste in the Saragossa prov- ince and determined dietary differ- ences according to sex and age. For their research, Guede and her colleagues applied geological tech- niques to learn more about gaps in knowledge that have arisen in other disciplines, such as archaeology and anthropology, regarding the fi nd- ings at Tauste. Excavations carried out in this municipality disinterred the skeletons of 44 Muslim individu- als who lived between the eighth and tenth centuries. On the basis of this discovery, a research group from the university’s Department of Mineral- ogy and Petrology undertook to ana- lyse dental samples of these human remains to establish the diet of this medieval Muslim community. on their own indicate nothing, but they are essential for supporting the hypotheses and discoveries of ar- chaeologists and historians,” empha- sised Dr Maria Cruz Zuluaga, one of Guede’s PhD supervisors. For exam- ple, even if the analyses do not reveal the origin of the animal protein, “we can assume that it came above all from sheep and goats on the basis of written texts and anthropological knowledge about medieval Muslim society,” she explained. In this respect, studies of this type provide proof that we are what we eat, according to Samuel Epstein (1951), a geologist famous for devel- oping methods for analysing stable isotopes. “What we eat goes on to form part of our bodies and provides us with very valuable information that ends up recorded in us—in this case in our teeth,” Guede said. The study focused on dentine, as it is more suitable than enamel for es- tablishing diet, according to the re- searcher. “The chemical composition of the dentine is gradually remod- elled throughout our lives and that is why the elements that form part of our diet are recorded during the fi nal years of people’s lives,” she stated. Sampling teeth with a laser tech- nique High lead concentrations in dentine Guede used laser ablation–induc- tively coupled plasma–mass spec- trometry to carry out targeted analy- ses of the teeth. An advantage of laser ablation is that the sample does not need much preparation; thus, it is not particularly aggressive on the fossil remains. This method there- fore allows such remains, which in archaeology are limited, to be pre- served for future studies. The chemical results uncovered the existence of considerable differences in the diet of adult men compared with that of women and younger people. The research suggested that adult males ate more protein of ani- mal origin than did the women and younger people, whose diets were richer in pulses and vegetables. The fi ndings of the research must be interpreted in the context of work by historians, anthropologists and archaeologists. “Numerical data In addition to the new fi ndings on diet, the research discovered high lead concentrations in the dentine of four individuals. “The concentration of lead is so high that it suggests that they were poisoned by this element,” Guede said. The origin of the lead in this case is anthropogenic and, ac- cording to various studies, could be due to the work these people did, which involved handling lead-bear- ing minerals, possibly in the produc- tion of glazes for ceramics. The study, titled “Analyses of hu- man dentine and tooth enamel by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP- MS) to study the diet of medieval Muslim individuals from Tauste”, was published in the January issue of the Microchemical Journal.