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S cientists at the Oak Ridge National Labora- tory (ORNL) have found the genetic code of bacteria, which could lead to treat- ments for periodontitis, ac- cording to a new study. The finding, published in Proceedings of the National Academy of Sciences, profiles the SR1 bacteria, a group of microbes present in many environments, ranging from the mouth to deep within the Earth, that have never been cultivated in the laboratory. Human oral SR1 bacteria are elevated in periodontitis, a disease marked by inflamma- tion and infection of the liga- ments and bones that support the teeth. Scientists also found that the SR1 bacteria employ a unique genetic code in which the codon UGA - a sequence of nucleotides guiding pro- tein synthesis - appears not to serve its normal role as a stop code. In fact, scientists found that UGA serves to introduce a glycine amino acid instead. “This is like discovering that in a language you know well there is a dialect in which the word stop means go,” said co-author Mircea Podar of the Department of Energy lab’s Biosciences Division. Podar and Dieter Söll of Yale Univer- sity led the team that also in- cluded scientists from DOE’s Joint Genome Institute who contributed to the analysis of the single-cell sequencing data. The researchers believe the altered genetic code lim- its the exchange of genes be- tween SR1 and other bacteria because they use a different genetic alphabet. “In the big pool of bacte- ria, genes can be exchanged between species and can con- tribute to increased antibiotic resistance or better adapta- tion to living in humans,” Po- dar said. “Because SR1 has a change in its genetic alphabet, its genes will not function in other microbes.” Podar and colleagues en- vision this work providing a path toward a better under- standing of microbiological factors of periodontitis as well as to the establishment of a framework to help scientists interpret genomic data from this bacterium and others that have the same altered genetic code. DT Human microbe study provides insight into periodontitis Genetic code discovery could help treat perio O xtex Limited, a recent spinout from the University of Ox- ford, will soon begin work with researchers at the Uni- versity of Malaya to develop its novel hydrogel tissue ex- panders to treat crossbite and transverse maxillary hypo- plasia. Jan Czernuszka, Lecturer in Materials at the University of Oxford, and Chief Techni- cal Officer of Oxtex, led the research into the development of the hydrogel-based tissue expander. He said, “This is a significant grant and we are delighted that the University of Malaya has recognised the potential of our products to treat deformities of the jaw. We are confident that the re- search into tailoring the de- vice for oral applications and the resulting clinical trials will lead to long-term benefits for an even broader range of surgical procedures.” Crossbite is a common problem in clinical dentistry. It can be painful and affects nearly one-in-ten of Malay- sia’s population. Associate Professor Zam- ri Radzi and Professor Noor Hayaty Abu Kasim of the Fac- ulty of Dentistry at the Uni- versity of Malaya said, “The established technique for mild to moderate cases of crossbite is to use a quad he- lix – a spring loaded appliance – that moves the teeth out- wards over a period of time. Whilst these are established techniques, there is a 30 per cent chance of relapse. The use of a self-expanding hy- drogel offers tissue expan- sion at a precisely controlled rate to produce increased surface area of the targeted soft tissues. Their action can also be delayed to allow swelling to commence after a predetermined time - nor- mally one to two weeks after implant - to allow the tissues to settle. This new approach is expected to reduce signifi- cantly the tendency to relapse, leading to better patient out- comes.” The £1.2M High Impact Re- search grant from the Ministry of Higher Education, Malay- sia will fund three Doctorate and four Masters places over a period of four years, and is expected to generate 35 sci- entific papers and at least one patent. DT UK tissue expander secures £1.2m research grant A n improvement may be in order for the most common dental anaes- thetic. The inferior alveolar nerve block is the most com- monly used form of local an- aesthesia for mandibular restorative and surgical pro- cedures. A study found that the addition of the drug man- nitol significantly increases the effectiveness of this an- aesthetic. The journal Anesthesia Pro- gress presents a study testing the efficacy of lidocaine with epinephrine compared with equal amounts of lidocaine with epinephrine plus man- nitol. After injection of the an- aesthetic, the subjects’ teeth were electric pulp tested for sensation. Pain of solution deposition and postoperative pain were also measured. Failure rates of 10 per cent to 39 per cent for the tra- ditional formulation of lido- caine and epinephrine have been reported. One reason may be that, because of the perineurial barrier around the nerve, the anaesthetic solu- tion does not completely dif- fuse into the nerve trunk. With mannitol, the anaesthetic so- lution permeates the nerve trunk in greater amounts, in- creasing the efficiency of the anaesthetic. The same 40 patients were given both drug combinations in two separate appointments at least one week apart. To blind the experiment, ran- dom five-digit numbers were assigned to each anaesthetic formulation, so neither the patients nor the personnel administering the anaesthetic knew which formulation was being given. An electric pulp tester was used to test the sensitivity of the patients’ teeth. A drop of toothpaste acts as a con- ductor of the electric current to the tooth. After the injec- tion of the nerve block, differ- ent teeth were tested once a minute in a repeating pattern for a total of 60 minutes. The patients also rated their expe- riences of lip numbness and postoperative pain on a scale of 0 to 3. No significant differences were found between the two treatments for pain of solution deposition and postoperative pain. However, the manni- tol treatment in this test was shown to be more effective for all teeth, offering a greater level of pain relief for dental patients. DT Dental anaesthesia more effective with mannitol Mannitol to help anaesthetic success? 4 News United Kingdom Edition April 1-7, 2013