FOR MORE INFORMATION with William Vaughan, BSN, RN VP of Education & Clinical Affairs JENNIFER HARDESTY Pharm.D., FASCP Chief Clinical Officer The Medication Pass: Can We do Better? (part 2) ROB SHULMAN BS, R.Ph., CGP, FASCP Building on information presented in the medication pass, the surveyor observes Director of Consultant Pharmacy Services June issue of the Pulse, we now look at
Revistargo.com.brORIGINAL ORIGINAL Non-surgical periodontal therapy for the treatment of chronic periodontitis Terapia periodontal não-cirúrgica no tratamento da periodontite crônica Mari Raquel Botlender TROJAHN1 Robert Carvalho da SILVA2 Júlio César JOLY2 The aim of this split-mouth controlled study was to compare the clinical benefits of administering subgingival 10% Doxycycline (test group) with a placebo gel (control group), as an adjunct to mechanical therapy in the treatment of chronic periodontitis. Fifteen patients with moderate to severe chronic periodontitis, with at least 2 pairs of comparable contralateral defects (pocket depth ≥6 mm), were selected. The subjects were submitted to initial periodontal treatment, which included oral hygiene advice and supra-gingival ultrasonic instrumentation at least one month before starting the experiments. Clinical attachment level (CAL), probing depth (PD) and gingival margin level (GML) were assessed at baseline, and after 3 and 6 months, using a manual probe (PCP-15, Hu Friedy). Plaque index was less than 20% throughout the study period. Comparison between groups indicated a PD reduction and CAL gain greater in the test group than in the control group at 3 and 6 months; however, no significant difference was shown (p>0,05). The findings suggest that 10% Doxycycline hyclate applied subgingivally as an adjunct to conventional periodontal treatment, did not promote additional benefit when compared to scaling and root planing with a placebo gel in patients with moderate to severe chronic periodontitis. Indexing terms: Chronic periodontitis. Dental scaling. Doxycycline. Comparar os benefícios clínicos da administração de gel composto de hiclato de doxiciclina a 10% (grupo teste) em relação ao gel placebo (grupo controle) associado à terapia mecânica no tratamento da periodontite crônica. Foram selecionados 15 pacientes com periodontite crônica moderada a severa, e um mínimo de 2 pares de defeitos contralaterais comparáveis (profundidade de sondagem ≥ 6mm). Os pacientes foram submetidos ao tratamento periodontal inicial, que incluiu instrução de higiene oral, instrumentação ultra-sônica pelo menos um mês antes do início do experimento. Os parâmetros clínicos: nível clínico de inserção (NCI), profundidade de sondagem (PS), e nível da margem gengival (NG) foram aferidos no início, após 3 e 6 meses utilizando uma sonda periodontal manual (PCP-15, Hu Friedy). O índice de placa se manteve inferior a 20% durante todo o estudo. As comparações entre os grupos indicaram que redução na PS e ganho no NCI foi maior no grupo teste do que no grupo controle aos 3 e 6 meses, porém, não houve diferença estatisticamente significante (p>0,05).
Esses achados sugerem que a aplicação subgengival de hiclato de doxiciclina gel a 10%, como adjunto ao tratamento periodontal convencional não promoveu benefício adicional ao tratamento com raspagem e alisamento radicular com aplicação de gel placebo, em pacientes com periodontite crônica moderada a severa.
Termos de indexação: Periodontite crônica. Raspagem dentária. Doxiciclina. 1 Faculdade São Leopoldo Mandic, Curso de Odontologia, Programa de Pós-Graduação em Periodontia. Rua José Rocha Junqueira, 13, Swift, 13045-755. Campinas, SP, Brazil. Correspondência para / Correspondence to: MRB TROJAHN. E-mail: <[email protected]>.
2 Universidade Estadual de Campinas, Faculdade de Odontologia. Piracicaba, SP, Brazil.
RGO - Rev Gaúcha Odontol., Porto Alegre, v.61, n.4, p. 529-534, out./dez., 2013 MRB TROJAHN et al.
were selected. For the test group, the sites in each hemi-arch were randomly treated with non-surgical periodontal The objective of conventional periodontal therapy instrumentation, followed by application of 10% is to eliminate the subgingival biofilm at sites affected by Doxycycline gel containing Methocel (-6-(hydroxymethyl)-periodontal disease, which may be associated to progressive destruction of supportive periodontal tissue1. Scaling and 3-yl]oxyoxane-3,4-diol-nomenclature IUPAC-) and 10% root planing alter the composition of the subgingival flora, Doxycycline hyclate (MASE Chemical and Pharmaceutical however, factors such as probe depth, bifurcation areas, Products Ltda., Cambuci, São Paulo, Brazil). The control and the presence of microorganisms within the cement group was treated in the same way, however, after scaling limit the effectiveness of instrumentation2-4.
and root planing a placebo gel (Methocel) only was applied. The idea of using locally applied medications This formula has already been used in other split-mouth in periodontal pockets as a treatment method has been double-blind randomized control studies11-13.
studied for more than 20 years. The clinical efficacy is The patients underwent initial periodontal derived from the capacity of the material to maintain its treatment consisting of supragingival ultrasonic concentration within the periodontal pocket for a given debridement and oral hygiene advice at least one month time period. Antimicrobial medications have been most before starting the experiment. This procedure allowed studied. The majority of the medications have been tested the clinician to perform scaling and root planing therapy in association with scaling and root planing, although in a single session so that the medication could be applied. some have also been studied as monotherapies5-6.
In addition, it provided the opportunity to level out the A slow sustained-release antimicrobial permits the individuals, as this was a small group study. During the application of medication at the affected site by means of initial examination, which was performed immediately a biodegradable system; therefore adequate drug levels prior to the experimental procedures, dichotomous plaque are achieved without the need for daily application and and bleeding indices, as well as the biometric parameters removal. Direct application also allows the use of small of probing depth (distance between the gingival margin quantities, therefore minimizing systemic absorption of the and the base of the pocket), level of gingival margin active ingredient7. (distance between the cemento-enamel junction and the Studies using the application of Doxycycline gel gingival margin) and clinical attachment level (the sum of associated with scaling and root planing have demonstrated the probing depth to the gingival level), using a manual a significant reduction in probe depth and improvements periodontal probe (PCP-15, Hu Friedy), to the nearest in clinical parameters8-10. These studies, therefore, highlight the importance of longitudinal studies to confirm the Six sites around each tooth, posterior or anterior, advantages of drug therapy in association with periodontal were measured, however, only the deepest site was considered. All clinical parameters were collected again at 3 and 6 months. Professional prophylaxis and patient motivation were performed during these periods, with the plaque index maintained at below 20% throughout the study. Probing guides were not performed in this study, Fifteen patients were selected from the dental however, the researcher aimed to use the same probe tip clinic at the Center for Dental Research, São Leopoldo and angulation, based on photographic evaluation. The Mandic University. Four male and 11 healthy female researcher calibrated the force applied during probing patients aged between 25 and 68 years with moderate to prior to the start of the experiment. The same operator severe chronic periodontitis and a minimum of 20 teeth, performed each stage of the study. were selected. Smokers, patients with known systemic 2% Lidocaine with epinephrine, 1:100.000 diseases, and those using medications that may interfere (ALPHACAINE-DFL) was administered before periodontal with tissue repair, such as anticoagulants or corticosteroids, instrumentation. The experimental procedure consisted were excluded from the study. Teeth with pulpal pathology of non-surgical periodontal instrumentation using specific were also excluded.
manual curettes (Hu Friedy) for the treated surfaces, Four sites from different teeth in the same dental followed by 10% Doxycycline hyclate or placebo gel arch, with two in each hemi-arch at a probe depth of ≥6mm, application. All of the curettes used were sufficiently RGO - Rev Gaúcha Odontol., Porto Alegre, v.61, n.4, p. 529-534, out./dez., 2013
Treatment of chronic periodontitis using Doxycycline Gel sharpened before each procedure, and instrumentation at a significance level of 5%, a significant difference was efficacy was subjectively evaluated clinically by obtaining a demonstrated between group and time, both for the hard, smooth and polished surface, using a manual scaled control and test groups, with baseline being significantly probe (PCP-15, Hu Friedy). The pockets were rigorously higher than all other time intervals. In terms of PD, when irrigated with physiological saline solution to remove clots comparing the group treated with Doxycycline gel (test and debris. The sites were randomly treated using syringes group) to the group treated using the placebo gel (control containing the test drug or placebo, which were coded A group) at 3 and 6 months, means of 4.27 mm versus 4.73 and B by the researcher responsible (RCS). This study was mm (difference = 0.46 mm) and 3.57 mm versus 3.93 mm double-blinded, with the coding kept confidential during (difference 0.36 mm), respectively, were demonstrated. the entire experimental period, and neither the operator The mean at 3 months was also significantly higher than at nor the patients knew which drug was being applied to 6 months. There was no significant difference in terms of which side. The gel was applied to the deepest part of the test and control group mean at all time intervals, therefore pocket until spillover at the gingival margin, as shown in the test group did not present a significant gain in probing Figure 1. The same operator treated the test and control depth compared to the control group (p>0.05). At 3 group sites on the same day.
months, p=0.098 suggests a trend towards significance This study adhered to the principals of ethics as per between the treatments used. the Declaration of Helsinki (2000), as well as the specific The variations in the Clinical Attachment Level legislations of Brazil (CEP n 06/198).
(CAL) did not demonstrate a significant difference between the study groups at baseline. Comparing the CAL of the test and control groups at 3 and 6 months, the means were 4.30 versus 4.70 mm (difference = 0.40 mm) and 3.57 versus 3.97 mm (difference = 0.40 mm), respectively. Using repeated measures Analysis of Variance complemented by the Tukey multiple comparisons test at a significance level of 5%, a significant interaction within each group with regards to time was shown, both in the Figure 1. Demonstration of gel application (placebo or 10% Doxycycline gel) used after scaling and root planing.
control and test groups, with the mean at baseline being significantly higher than at all other time periods. The mean at 3 months was also significantly higher than at 6 months. At all time periods, no significant difference was shown with regards to the mean of the groups (p>0.005).
The mean values of the clinical parameters for Table 1. Mean and standard deviations for the control (A) and test (B) groups at the patients with moderate to severe chronic periodontitis baseline, and 3 and 6 months, using the variables PD, CAL and GML.
treated with scaling and root planing, and application of either the placebo or the Doxycycline gel, are shown in The Gingival Margin Level (GML) did not reveal a significant difference between the groups at the specified time intervals, nor within the same group at different time periods. Only one patient had a gingival margin measurement of more than zero, with the remaining patients demonstrating a GML, which coincided with the The values for probing depth (PD) revealed no significant difference between the groups at baseline. However, using repeated measures Analysis of Variance, Note: The mean followed by different upper case letters on the same row denote a significant difference and the mean followed by different lower case letters in the same column denote complemented by the Tukey multiple comparisons test a significant difference, as per repeated measures Analysis of Variance, complemented by the Tukey multiple comparisons test, at a significance level of 5%.
RGO - Rev Gaúcha Odontol., Porto Alegre, v.61, n.4, p. 529-534, out./dez., 2013
MRB TROJAHN et al.
in bleeding on probing, probing depth and clinical attachment level were only observed for the test group, which received scaling and Doxycycline gel, at 3 months and for a minority of bacterial species at 2 years. Despite the short-term results in favor of the use of Doxycycline gel, annual applications have not shown better clinical or microbiological results when compared with results following mechanical treatment only20.
Therapy association has been the aim of many studies. A clinical study used the following treatments: Figure 2. Means for control (A) and test (B) groups at baseline, 3 months and 6
Scaling and root planing + Doxycycline gel application (test months, for the variable CAL, presented in error bars with standard error.
group), and scaling and root planing only (control group). The gains in clinical attachment level were greater in the test group. Concluding that the use of Doxycycline could be an There are different rationales for the topical important adjunct in the treatment of severe periodontitis application of subgingival antimicrobials in clinical in smokers14. The clinical effect of topical Doxycycline gel periodontology, namely the persistence of active sites application with non-surgical periodontal therapy was also following surgical and non-surgical treatment, or a evaluated. The test group presented significantly improved recurrence during periodontal support therapy14. The probing depth and clinical attachment levels after 6 months, advantage of this procedure is that it is less aggressive when compared to the control group. Another 6-month towards the periodontal hard tissue and causes less study indicated that subgingival instrumentation combined dentinal sensitivity, which is a common occurrence after with local Doxycycline application at deep periodontal sites conventional scaling.
justified it as a treatment for chronic periodontitis15. In pharmacokinetic analysis of Doxycycline in Both groups evaluated in this study presented a the Gingival Crevicular Fluid (GCF), saliva and blood, the reduced probing depth within the evaluated time periods, antimicrobial effect was shown to be limited to the sites in addition to a gain in clinical attachment level after 3 and 6 months; however, no significant difference was where the drug was applied. Doxycycline gel possesses shown at the same time period between the groups. clinical and pharmacokinetic properties that effectively These results corroborate other studies, which suggest release and maintain antimicrobial levels within the that subgingival application of Doxycycline gel results in an periodontal pocket for at least a week, without the need additional clinical improvement in periodontal therapy in for greater drug retention within the periodontal tissues15. patients with Type I Diabetes, with a significant difference In this study, a split-mouth approach was used, in between the study groups noted only after 12 months16. which both treatments were applied in the same patient. The combined use of Doxycycline gel and scaling and root Multiple studies with the same design have been published planing to suppress odontopathogens was also evaluated. evaluating the local release of these agents16-19.
The sites that received both scaling and root planing in The present study was designed to evaluate association with subgingival Doxycycline gel application, as the benefits of the use of Doxycycline gel as an adjunct well as those sites that received scaling only, showed similar to conventional periodontal scaling and root planing in levels of periodontopathogens before and after treatment, patients with moderate to severe chronic periodontitis. demonstrating that there was no significant difference with The combined therapy used demonstrated favorable the use of Doxycycline gel. In accordance with the findings results in terms of improvements in the evaluated clinical of the present study, studies which compared the use of parameters. The same results were seen in the study, which Doxycycline gel with scaling and root planing resulted in evaluated the clinical and microbiological effects on the very similar clinical changes at all times in both studies. The mean gain of clinical attachment level was practically the controlled local application of Doxycycline as an adjunct same for both groups during the research. to mechanical treatment for periodontitis. The clinical The likely explanations for not observing a parameters were measured at baseline, 3 months, and 1, significant difference between the groups could be 2 and 3 years. Gingival biofilm samples were collected at associated to the sample and time intervals evaluated. It is each time interval and evaluated. Significant reductions known that the larger the number of sites, the lower the RGO - Rev Gaúcha Odontol., Porto Alegre, v.61, n.4, p. 529-534, out./dez., 2013 Treatment of chronic periodontitis using Doxycycline Gel numeric difference to reach significance. In addition, the The results revealed changes in PD and CAL of 2.5 sites that received Doxycycline could show more stability in mm or more in the experimental group, which was higher the long-term, and the control group sites could begin to than that of the control group. lose attachment over a longer follow-up, whilst those of the The primary indication for Doxycycline gel, in test group could be maintained. The results of the present addition to all other locally applied antimicrobials, is its study demonstrated that the deeper sites (≥7mm) of the use as an adjunct to conventional scaling and root planing test group obtained greater attachment gain (≥2mm).
treatment29. Studies have shown significant improvements Although clinical studies that compared different in the evaluated clinical parameters, which suggest the drugs to treat periodontitis have shown that patients use of 10% Doxycycline hyclate gel to treat subgingival treated with Doxycycline gel obtained a significant increase periodontitis, producing an additional favorable clinical in clinical attachment gain when compared to patients result to conventional periodontal therapy in patients receiving other drugs, the use of all drugs has shown with chronic periodontitis. Every case, however, should satisfactory clinical gain21-24. When tested as an adjunct to be evaluated individually, and it should be used when a conventional periodontal therapy, beneficial results were significant clinical result is anticipated30. reported25-27.
Many drugs have been used as a single treatment system, therefore, without the use of scaling and root CONCLUSION
planing. Some authors have shown that monotherapy
has its benefits in the treatment of chronic periodontitis.
From the results obtained in this 6-month study, Controlled clinical studies have concluded that the it can be concluded that no significant difference was application of Doxycycline gel was superior to sanguinarine shown between the groups at the time intervals studied. chloride hydrate and the vehicle control at reducing In accordance with the results, subgingival application of probing depth at all evaluated time periods. The results 10% Doxycyline hyclate gel as an adjunct to conventional suggested that Doxycycline gel in a biodegradable system periodontal treatment did not promote any additional was an effective way to reduce clinical signs of chronic benefit when compared to scaling and root planing with periodontitis, with a safe and benign profile28. The aim of the application of a placebo gel in patients with moderate the present study was to perform manual instrumentation to severe chronic periodontitis.
prior to the application of Doxycycline to disorganize the biofilm, favoring drug action. In monotherapies, this Collaborators preceding disorganization does not exist.
In this study, the experimental sites received scaling and root planing followed by the application of MRB TROJAHN was responsible for the research 10% Doxycycline gel, with no patient loss throughout the and writing the article. RC SILVA participated in the study. The patients demonstrated effective biofilm control research, interpretation of results and writing the article. during the research, maintaining indices lower than 20%. JC JOLY participated in analysis and interpretation of the results, and writing the article.
3. Loos B, Claffey N, Egelberg J. Clinical and microbiological effects of root debridement in periodontal furcation pockets. J Clin Periodontol. 1988;15(7):453-63. doi: doi: 10.1111/j.1600- 1. Garret S, Johnson L, Drisko CH, Adams DF, Bandt C, Beiswanger B. Two multi-center studies evaluating locally delivered doxycycline hyclate, placebo control, oral hygiene, and scaling 4. Fleischer HC, Mellonig JT, Brayer WK, Gray JL, Barnnet JD. Scaling and root planing in the treatment of periodontitis. J Periodontol. and root planing efficacy in multirooted teeth. J Periodontol. 2. Rosenberg ES, Evian CI, Listgarden MA. The composition of the 5. Finkelmann RD, Williams RC. Local delivery of chemotherapeutic subgingival microbiota after periodontal therapy. J Periodontol. agents inperiodontal therapy: Has its time arrived? J Clin Periodontol. 1998;25(11 Pt 2):943-6. doi: 10.1111/j.1600- RGO - Rev Gaúcha Odontol., Porto Alegre, v.61, n.4, p. 529-534, out./dez., 2013 MRB TROJAHN et al.
6. Killoy WJ. The clinical significance of local chemoterapies. J Clin 19. Wong MY, Lu CL, Liu CM, Hou LT. Microbiological response of localized sites with recurrent periodontitis in maintenance patients treated with tetracycline fibers. J Periodontol. 1999;70(8):861-8. 7. Kormann KS. Controlled-release local delivery antimicrobials in periodontics: prospects for the future. J Periodontol. 1993;64(8 20. Bogren A, Teles RP, Torresyap G, Haffajee AD, Socransky S, Wennstrom J. Locally delivered doxycycline during 8. Polson AM, Southard GL, Dunn RL, Yewev GL, Godowski KC, supportive periodontal therapy: a 3 - year study. J Periodontol. Polson AP, et al. Periodontal pocket treatment in beagle dogs using subgingival doxycycline from a biodegradable system. I. Initial clinical responses. J Periodontol. 1996;67(11):1176-84. 21. Jorgensen MG, Safarian A, Daneshmand N, Keim RJ, Slots J. Initial antimicrobial effect of controlled-release doxycycline in subgingival sites. J Periodontol. 2004;39(5):315-9. doi: 9. Polson AM, Garret S, Stoller NH, Bandt CL, Hanes PJ, Killoy WJ, et al. Multi-center comparative evaluation of subgingivally delivered sanguinarine and doxycycline in the treatment of 22. Salvi GE, Mombelli A, Mayfield I, Rutar A, Suvan J, Garret S, et periodontitis.II. Clinical results. J Periodontol. 1997;68(2):119- al. Local antimicrobial therapy after initial periodontal treatment. 126. doi: 10.1902/jop.1918.104.22.168.
J Clin Periodontol. 2002;29(6):540-50. doi: 10.1034/j.1600- 10. O'Leary TJ, Drake RB, Naylor JE. The plaque control record. J Periodontol. 1972;43(1):38. doi: 10.1902/jop.1922.214.171.124.
23. Breault LG, Spadaro SE. Local chemotherpeutics as an adjunct to scaling and root planing. Dental Assistant. 200473(6):20-4.
11. Machion L, Andia DC, Benatti BB, Carvalho MD, Nogueira-Filho GR Casati M, et al. Locally delivered doxycycline as an adjunctive 24. Killoy WJ. The use of locally-delivered chlorhexidine in the therapy to scaling and root planing in the treatment of smokers: treatment of periodontitis. Clinical results. J Clin Periodontol. a clinical study. J Periodontol. 2004;77(4):606-13. doi:10.1902/ 1998;25(11 Pt 2):953-8. doi: 10.1111/j.1600-051X.1998.
12. Wennstrom JL, Newman HN, MacNeill SR, Killoy WJ, Griffiths GS, 25. Rodrigues IFG, Machion L, Casati MZ, Notici Junior FH, De Toledo Gillam DG, et al. Utilisation of locally delivered doxycycline in S, Sallum AW, et al. Clinical evaluation of the use of locally non-surgical treatment of chronic periodontitis. A comparative delivered chlorhexidine in periodontal maintenance therapy. J multi-centre trial of 2 treatment approaches. J Clin Periodontol. Periodontol. 2007;78(4):624-8. doi: 10.1902/jop.2007.060317.
26. Paolantonio MP, D'Angelo M, Grassi RF, Perinetti G, Piccolomini 13. De Lima MAF, Cury CC, Palioto DB, Duro AM, Da Silva RC, R, Pizzo G, et al. Clinical and microbiologic effects of subgingival Wolf LF. Therapy with adjuntive doxycycline local delivery in contolled-release delivevery of chlorhexidine chip in the pacients with Type 1 diabetes mellitus and periodontitis. J treatment of periodontitis: a multicenter study. J Periodontol. Clin Periodontol. 2004;31(8):648-53. doi: 10.1111/j.0303- 27. Cosyn J, Wyn I, Rouck T, Sabzevar MM. Subgingival chlorhexidine 14. Eickholz P, Kim TS, Schacher B, Reitmeir P, Burklin T, Ratka- varnish administration as an adjunte to same-day full-mouth root Kruger P. Subgingival topical doxycycline versus mechanical planing. I. Clinical observations. J Periodontol. 2007;78(3):430- debridement for supportive periodontal therapy: a single 7. doi: doi:10.1902/jop.2007.060221.
blind randomized controlled two-center study. Am J Dent. 2005;18(6):341-6. 28. Grisi DC, Salvador SL, Figueiredo LC, Souza SLS, Novaes Junior SB, Grisi MFM. Effect of controlled-release chlorhexidine 15. Kim TS, Bürklin T, Schacher B, Ratka-Krüger P, Schaecken chip on clinical and microbilological parameters síndrome. J MT, Rengggli HH, et al. Pharmacokinetic profile of a locally Clin Periodontol. 2002;29(10);875-81. doi: 10.1034/j.1600- administered doxycycline gel in crevicular fluid, blood, end 051X.2002.291001.x. saliva. J Periodontol. 2002;73(11):1285-91. doi: 10.1902/ 29. John V, Philips G. Locally delivered antimicrobials in periodontal treatment. J Indiana Dent Assoc. 2002;81(2):10-4.
16. Stabholz A, Nicholas AA, Zimmerman GJ, Wikesjo UM. Clinical and antimicrobial effects of a single episode of subgingival 30. Lotufo R, Kantorski K, Zimmermann G. Antibióticos de liberação irrigation with tetracycline HCI or chlorhexidine in deep local e controlada em periodontia: minociclina e doxiciclina. periodontal pockets. J Clin Periodontol. 1998;25(10):794-800. RGO - Rev Gaúcha Odontol. 2003;51(5):395-7.
17. Ciancio SG, Charles MC, Leung M. Tissue concentration and localization of tetracycline following site-specific tetracycline fiber therapy. J Periodontol. 1992;63(10):849-53. doi: 10.1902/ 18. Fine JB, Harper DS, Gordon JM, Hovliaras CA, Charles CH. Short- term microbiological and clinical effects of subgingival irrigation Received on: 13/7/2009 with an antimicrobial mouthrinse. J Periodontol. 1994;65(1):30- Final version resubmitted on: 22/3/2010 6. doi: 10.1902/jop.19126.96.36.199.
Approved on: 31/3/2010 RGO - Rev Gaúcha Odontol., Porto Alegre, v.61, n.4, p. 529-534, out./dez., 2013
REPUBLIC OF RWANDA MINISTRY OF AGRICULTURE AND ANIMAL RE SOURC ES Land-husbandry, Water-harvesting and Hillside-irrigation (LWH) projec t Pest Management Plan (PMP) and Arrangemen t for LWH FINAL REPORT Updated October, 2013 THE GOVERNMENT OF RWANDA P.O. Box 6961, Kigali, Rwanda