A Doença Periodontal é causada pelo acúmulo de placa bacteriana sobre os dentes e estruturas adjacentes. As plantas medicinais são utilizadas como um meio de tratamento há muitos anos, sendo o resultado do acúmulo do conhecimento popular. No entanto, elas são utilizadas com pouco critério. Do ponto de vista da odontologia, as plantas medicinais ainda têm sido pouco estudadas. A comprovação clínica dos efeitos do sumo de Kalanchoe gastonis-bonnieri (KGB) a 10% sobre o desenvolvimento do biofilme bacteriano e cálculo dentário em cães pode oferecer alternativa valiosa para o tratamento e prevenção da doença periodontal, ou o prolongamento dos efeitos do tratamento cirúrgico clássico. Desta forma, seriam reduzidos os riscos do tratamento cirúrgico, o custo terapêutico, o surgimento de cepas bacterianas resistentes, e a ocorrência de efeitos colaterais, além de serem fornecidos subsídios para uso em outras espécies, inclusive a humana, com aproveitamento de recursos naturais amplamente disponíveis e ainda pouco conhecidos e utilizados, propiciando a transferência tecnológica para o setor produtivo. O presente estudo objetivou utilizar o método de análise computadorizada, para medição de área de placa bacteriana e cálculo dentário nos dentes de cães, por meio da comparação entre os grupos tratado (sumo de KGB a 10%), controle negativo (solução fisiológica a 0,9%) e controle positivo (gluconato de clorexidina a 0,12%). Foram utilizados 34 cães da raça Beagle com similares características e mantidos sob o mesmo manejo e dieta alimentar. As avaliações da cavidade oral após o tratamento periodontal sob anestesia geral inalatória, dia zero, ocorreram para placa bacteriana, no dia sete, e para cálculo dentário, no dia. O sumo de Kalanchoe gastonis-bonnieri a 10% apresentou eficácia no controle da formação da placa bacteriana em relação ao grupo controle negativo, e do cálculo dentário em relação aos grupos controles negativo e positivo, obtendo-se diferença significante para estes três julgamentos. Então, este poderia ser utilizado como um coadjuvante na prevenção da doença periodontal. São necessários estudos complementares a longo prazo para comprovação da ausência efeitos colaterais, além da descoberta do mecanismo de ação do sumo de Kalanchoe gastonis-bonnieri a 10% sobre o biofilme bacteriano e o cálculo dentário. / The Periodontal Disease is caused by dental plaque accumulation on teeth and adjacent structures. Medicinal plants are used as a means treatment for many years, being the result of the accumulation of popular knowledge. However, they are used with little criterion. From the standpoint of Dentistry, the medicinal plants still has been little studied. The clinical proof of the effects of the extract of the plant Kalanchoe gastonis-bonnieri (KGB) on biofilm and calculus in dogs can offer valuable alternative for the treatment and prevention of periodontal disease, or even a continuation of treatment effects surgical classic. Thus, the risks would be reduced from surgical treatment, the cost of therapy, the emergence of resistant bacterial strains, and the occurrence of side effects, and subsidies are provided for use in other species, including humans, with use of natural resources widely available and still little known and used, providing, including technology transfer to the productive sector. This study aims to evaluate the computerized analysis method for measurement of dental plaque and calculus areas on the teeth of dogs, by comparison between the traded (10% of KGB juice), negative control group (0,9% of saline solution) and positive control group (chlorhexidine 0.12% sprayed in the oral cavity daily). 34 Beagle dogs with similar characteristics and kept under the same management and diet were used. Evaluations of oral cavity after the periodontal treatment (performed under general inhalation anesthesia) and after seven days for dental plaque, and 28 for calculus. The 10% of Kalanchoe gastonis-bonnieri juice showed efficacy in controlling the formation of plaque compared to the negative control group, and dental calculus in relation to negative and positive control groups, obtaining significant difference for these three trials. Thus, this could be used as an adjunct in the prevention of periodontal disease. Nevertheless, further studies are needed to prove the long-term absence of side effects, in addition, the discovery of the mechanism of action of to 10% Kalanchoe gastonis-bonnieri juice on the bacterial biofilm and dental calculus formation.

Entre os métodos de prevenção da cárie dentária, os controles mecânico e químico do biofilme dentário são de grande relevância neste processo. O controle mecânico é eficaz desde que executado diariamente e sistematicamente envolver todas as superfícies dentárias expostas ao meio bucal. Ele pode ser realizado pelo odontólogo por meio da profilaxia profissional e pelo próprio paciente pela escovação dentária. O controle químico do biofilme dentário deve ser empregado de forma suplementar, quando o controle mecânico não puder ser realizado diariamente ou se for realizado de forma inadequada acarretando o risco do acúmulo do biofilme dentário e como consequência, a ocorrência de lesões de cárie dentária e/ou da doença periodontal. O ideal seria associar ambos os métodos, para que um compense a deficiência do outro. É nesta direção que inúmeros estudos são feitos nos últimos anos. Para o controle químico, são relatadas na literatura inúmeras substâncias antimicrobianas. Dentre os agentes químicos recomendados, a clorexidina (CLX) tem se mostrado eficiente para esta finalidade, porém, sua aplicação apresenta limitações como: manchamento de áreas desmineralizadas dos dentes e perda do paladar, condições estas que limitam seu uso por tempo prolongado. Sendo assim, a busca de alternativas para o controle microbiano do biofilme dentário é de grande relevância para se somar aos esforços ora empreendidos neste sentido. Nas últimas décadas o emprego da luz associada a corantes surgiu como um tratamento alternativo ao uso de agentes antimicrobianos tradicionais. Este tratamento é chamado terapia fotodinâmica (TFD), sendo recentemente também chamado de Terapia Fotodinâmica Antimicrobiana (TFDA). Na TFDA, a luz interage com o corante que está associado ao microorganismo, sendo capaz de inibir sua proliferação ou eliminá-lo completamente. Poucos são os estudos que avaliam a ação antimicrobiana da TFD sobre biofilmes cariogênicos. A comprovação da eficácia dessa terapia sobre o biofilme dentário humano poderá ter um impacto positivo para a Odontologia, favorecendo a implantação de novos protocolos de controle químico do mesmo. Este estudo teve como objetivo analisar comparativamente o efeito da clorexidina e da TFDA (com dois tipos de fotossensibilizadores: Azul de Toluidina O (TBO) e Clorofila Líquida (CL)) sobre biofilmes dentários humanos formados in situ. Voluntários utilizaram um dispositivo intrapalatino contendo espécimes de esmalte dental, sobre os quais biofilme dentário foi formado. Após 48 horas, diferentes terapias foram aplicadas sobre o biofilme: (1) água destilada: controle negativo; (2)CLX; (3) irradiação por laser; (4) TBO; (5) TBO +laser; (6) CL; (7) CL + laser. O biofilme então foi coletado e solubilizado. Em seguida, amostras foram semeadas em placas de Petri com diferentes meios de cultura, para contagem do número de microrganismos totais, estreptococos totais, Streptococcos mutans, Lactobacilos e Candida albicans. Amostras também foram coradas com Laranja de Acridina e visualizadas em microscopia de fluorescência, para análise da viabilidade das células presentes. Os resultados dos plaqueamentos apenas nos deram informações sobre os microrganismos totais e estreptococos totais, mostrando que a única redução significante dos microorganismos em relação ao grupo (1) ocorreu no grupo tratado por CLX (2). As outras terapias mostraram uma sensível redução. A viabilidade por microscopia por fluorescência se mostrou semelhante em todos os grupos. A clorexidina, portanto, comprovou seu efeito antimicrobiano, porém mais estudos precisam ser realizados para verificar o real papel da TFD sobre biofilme dentário humano. / The mechanical and chemical controls of dental plaque are important methods of caries prevention. The mechanical control is efficient if its run properly and daily. It can be made by a dentist (professional cleaning) or by patients themselves (toothbrushing). The chemical control should be used additionally, when the mechanical control cant be performed properly, them the biofilm can accumulate and in consequence, there are risks of dental caries or periodontal disease. For chemical control, many antimicrobial substances are related in literature. Several studies have shown that chlorexidine (CLX) is an effective antimicrobial substance against dental plaque. However, it presents some limitations like: tooth staining, loss of taste, conditions that limit its use by prolonged periods. Therefore, the search by new alternatives in microbial control of plaque is very important for improvement the treatment. In last decades, the use of light for activation of a photosensitizer appears like an alternative treatment with antimicrobial function. This treatment is called Photodynamic Therapy (PDT), recently Photochemotherapy (PACT). In PACT, the light activates a photosensitizer that is bond in microorganism and it can kill it or inhibit its growing. If this treatment is effective on human dental plaque, it will have positive impact for Dentistry and new protocols of chemical control will be developed. The present study aim was analyze the chlorexidine effect and the PDT effect (using Toluidine blue (TBO) and Liquid Chlorophyll (LC) like photosensitizer) in human natural dental plaque formed in situ. Volunteers wore a palatal appliance containing bovine enamel blocks, where the biofilm was formed. After 48 hours, different therapies were performed on plaque: (1) distilled water: negative control; (2) CLX; (3) Laser irradiation; (4) TBO; (5) TBO + Laser; (6) CL; (7) CL + Laser. The plaque samples were collected and dispersed. Next, serial dilutions were prepared and seeded onto different culture broth for the determination of the number of colony-forming units per gram (CFU/g) of total microorganisms, total Streptococcus, Streptococcus mutans, Lactobacillus and C. albicans. Samples were stained with acridine orange to analyze cells viability. The results can reveal only information about total microorganism and total Streptococcus. When the groups (2-7) were compared with the group (1), significant microbial reduction was observed only in group treated with CLX (3). The other therapies showed only a discrete reduction in relation of group (1). The cell viability showed similar results in all groups. Therefore, the CLX proved its antimicrobial effect. More studies are necessary for exact evaluation of effect of TFD on dental plaque human.

A Doença Periodontal é causada pelo acúmulo de placa bacteriana sobre os dentes e estruturas adjacentes. As plantas medicinais são utilizadas como um meio de tratamento há muitos anos, sendo o resultado do acúmulo do conhecimento popular. No entanto, elas são utilizadas com pouco critério. Do ponto de vista da odontologia, as plantas medicinais ainda têm sido pouco estudadas. A comprovação clínica dos efeitos do sumo de Kalanchoe gastonis-bonnieri (KGB) a 10% sobre o desenvolvimento do biofilme bacteriano e cálculo dentário em cães pode oferecer alternativa valiosa para o tratamento e prevenção da doença periodontal, ou o prolongamento dos efeitos do tratamento cirúrgico clássico. Desta forma, seriam reduzidos os riscos do tratamento cirúrgico, o custo terapêutico, o surgimento de cepas bacterianas resistentes, e a ocorrência de efeitos colaterais, além de serem fornecidos subsídios para uso em outras espécies, inclusive a humana, com aproveitamento de recursos naturais amplamente disponíveis e ainda pouco conhecidos e utilizados, propiciando a transferência tecnológica para o setor produtivo. O presente estudo objetivou utilizar o método de análise computadorizada, para medição de área de placa bacteriana e cálculo dentário nos dentes de cães, por meio da comparação entre os grupos tratado (sumo de KGB a 10%), controle negativo (solução fisiológica a 0,9%) e controle positivo (gluconato de clorexidina a 0,12%). Foram utilizados 34 cães da raça Beagle com similares características e mantidos sob o mesmo manejo e dieta alimentar. As avaliações da cavidade oral após o tratamento periodontal sob anestesia geral inalatória, dia zero, ocorreram para placa bacteriana, no dia sete, e para cálculo dentário, no dia. O sumo de Kalanchoe gastonis-bonnieri a 10% apresentou eficácia no controle da formação da placa bacteriana em relação ao grupo controle negativo, e do cálculo dentário em relação aos grupos controles negativo e positivo, obtendo-se diferença significante para estes três julgamentos. Então, este poderia ser utilizado como um coadjuvante na prevenção da doença periodontal. São necessários estudos complementares a longo prazo para comprovação da ausência efeitos colaterais, além da descoberta do mecanismo de ação do sumo de Kalanchoe gastonis-bonnieri a 10% sobre o biofilme bacteriano e o cálculo dentário. / The Periodontal Disease is caused by dental plaque accumulation on teeth and adjacent structures. Medicinal plants are used as a means treatment for many years, being the result of the accumulation of popular knowledge. However, they are used with little criterion. From the standpoint of Dentistry, the medicinal plants still has been little studied. The clinical proof of the effects of the extract of the plant Kalanchoe gastonis-bonnieri (KGB) on biofilm and calculus in dogs can offer valuable alternative for the treatment and prevention of periodontal disease, or even a continuation of treatment effects surgical classic. Thus, the risks would be reduced from surgical treatment, the cost of therapy, the emergence of resistant bacterial strains, and the occurrence of side effects, and subsidies are provided for use in other species, including humans, with use of natural resources widely available and still little known and used, providing, including technology transfer to the productive sector. This study aims to evaluate the computerized analysis method for measurement of dental plaque and calculus areas on the teeth of dogs, by comparison between the traded (10% of KGB juice), negative control group (0,9% of saline solution) and positive control group (chlorhexidine 0.12% sprayed in the oral cavity daily). 34 Beagle dogs with similar characteristics and kept under the same management and diet were used. Evaluations of oral cavity after the periodontal treatment (performed under general inhalation anesthesia) and after seven days for dental plaque, and 28 for calculus. The 10% of Kalanchoe gastonis-bonnieri juice showed efficacy in controlling the formation of plaque compared to the negative control group, and dental calculus in relation to negative and positive control groups, obtaining significant difference for these three trials. Thus, this could be used as an adjunct in the prevention of periodontal disease. Nevertheless, further studies are needed to prove the long-term absence of side effects, in addition, the discovery of the mechanism of action of to 10% Kalanchoe gastonis-bonnieri juice on the bacterial biofilm and dental calculus formation.

Entre os métodos de prevenção da cárie dentária, os controles mecânico e químico do biofilme dentário são de grande relevância neste processo. O controle mecânico é eficaz desde que executado diariamente e sistematicamente envolver todas as superfícies dentárias expostas ao meio bucal. Ele pode ser realizado pelo odontólogo por meio da profilaxia profissional e pelo próprio paciente pela escovação dentária. O controle químico do biofilme dentário deve ser empregado de forma suplementar, quando o controle mecânico não puder ser realizado diariamente ou se for realizado de forma inadequada acarretando o risco do acúmulo do biofilme dentário e como consequência, a ocorrência de lesões de cárie dentária e/ou da doença periodontal. O ideal seria associar ambos os métodos, para que um compense a deficiência do outro. É nesta direção que inúmeros estudos são feitos nos últimos anos. Para o controle químico, são relatadas na literatura inúmeras substâncias antimicrobianas. Dentre os agentes químicos recomendados, a clorexidina (CLX) tem se mostrado eficiente para esta finalidade, porém, sua aplicação apresenta limitações como: manchamento de áreas desmineralizadas dos dentes e perda do paladar, condições estas que limitam seu uso por tempo prolongado. Sendo assim, a busca de alternativas para o controle microbiano do biofilme dentário é de grande relevância para se somar aos esforços ora empreendidos neste sentido. Nas últimas décadas o emprego da luz associada a corantes surgiu como um tratamento alternativo ao uso de agentes antimicrobianos tradicionais. Este tratamento é chamado terapia fotodinâmica (TFD), sendo recentemente também chamado de Terapia Fotodinâmica Antimicrobiana (TFDA). Na TFDA, a luz interage com o corante que está associado ao microorganismo, sendo capaz de inibir sua proliferação ou eliminá-lo completamente. Poucos são os estudos que avaliam a ação antimicrobiana da TFD sobre biofilmes cariogênicos. A comprovação da eficácia dessa terapia sobre o biofilme dentário humano poderá ter um impacto positivo para a Odontologia, favorecendo a implantação de novos protocolos de controle químico do mesmo. Este estudo teve como objetivo analisar comparativamente o efeito da clorexidina e da TFDA (com dois tipos de fotossensibilizadores: Azul de Toluidina O (TBO) e Clorofila Líquida (CL)) sobre biofilmes dentários humanos formados in situ. Voluntários utilizaram um dispositivo intrapalatino contendo espécimes de esmalte dental, sobre os quais biofilme dentário foi formado. Após 48 horas, diferentes terapias foram aplicadas sobre o biofilme: (1) água destilada: controle negativo; (2)CLX; (3) irradiação por laser; (4) TBO; (5) TBO +laser; (6) CL; (7) CL + laser. O biofilme então foi coletado e solubilizado. Em seguida, amostras foram semeadas em placas de Petri com diferentes meios de cultura, para contagem do número de microrganismos totais, estreptococos totais, Streptococcos mutans, Lactobacilos e Candida albicans. Amostras também foram coradas com Laranja de Acridina e visualizadas em microscopia de fluorescência, para análise da viabilidade das células presentes. Os resultados dos plaqueamentos apenas nos deram informações sobre os microrganismos totais e estreptococos totais, mostrando que a única redução significante dos microorganismos em relação ao grupo (1) ocorreu no grupo tratado por CLX (2). As outras terapias mostraram uma sensível redução. A viabilidade por microscopia por fluorescência se mostrou semelhante em todos os grupos. A clorexidina, portanto, comprovou seu efeito antimicrobiano, porém mais estudos precisam ser realizados para verificar o real papel da TFD sobre biofilme dentário humano. / The mechanical and chemical controls of dental plaque are important methods of caries prevention. The mechanical control is efficient if its run properly and daily. It can be made by a dentist (professional cleaning) or by patients themselves (toothbrushing). The chemical control should be used additionally, when the mechanical control cant be performed properly, them the biofilm can accumulate and in consequence, there are risks of dental caries or periodontal disease. For chemical control, many antimicrobial substances are related in literature. Several studies have shown that chlorexidine (CLX) is an effective antimicrobial substance against dental plaque. However, it presents some limitations like: tooth staining, loss of taste, conditions that limit its use by prolonged periods. Therefore, the search by new alternatives in microbial control of plaque is very important for improvement the treatment. In last decades, the use of light for activation of a photosensitizer appears like an alternative treatment with antimicrobial function. This treatment is called Photodynamic Therapy (PDT), recently Photochemotherapy (PACT). In PACT, the light activates a photosensitizer that is bond in microorganism and it can kill it or inhibit its growing. If this treatment is effective on human dental plaque, it will have positive impact for Dentistry and new protocols of chemical control will be developed. The present study aim was analyze the chlorexidine effect and the PDT effect (using Toluidine blue (TBO) and Liquid Chlorophyll (LC) like photosensitizer) in human natural dental plaque formed in situ. Volunteers wore a palatal appliance containing bovine enamel blocks, where the biofilm was formed. After 48 hours, different therapies were performed on plaque: (1) distilled water: negative control; (2) CLX; (3) Laser irradiation; (4) TBO; (5) TBO + Laser; (6) CL; (7) CL + Laser. The plaque samples were collected and dispersed. Next, serial dilutions were prepared and seeded onto different culture broth for the determination of the number of colony-forming units per gram (CFU/g) of total microorganisms, total Streptococcus, Streptococcus mutans, Lactobacillus and C. albicans. Samples were stained with acridine orange to analyze cells viability. The results can reveal only information about total microorganism and total Streptococcus. When the groups (2-7) were compared with the group (1), significant microbial reduction was observed only in group treated with CLX (3). The other therapies showed only a discrete reduction in relation of group (1). The cell viability showed similar results in all groups. Therefore, the CLX proved its antimicrobial effect. More studies are necessary for exact evaluation of effect of TFD on dental plaque human.

Magister Chirurgiae Dentium (MChD) / Chlorhexidine has been established as the gold standard against which new chemical plaque control agents are tested (Jones, 1997). The addition of alcohol in a chlorhexidine mouthwash had been widely used, however the comparative efficacy of alcohol free chlorhexidine mouthwash had not fully been explored in this study, two chlorhexidine mouthwash preparations were tested to evaluate their comparative efficacy in the treatment of periodontal disease. Aims: To assess the efficacy of alcohol-free chlorhexidine mouth wash in comparison to alcohol containing chlorhexidine mouth wash. Objectives: To determine pre- and post- operative clinical parameters and microbial load in the management of patients with chronic periodontitis. Methodology: A double blinded randomised control trial was conducted. Patients diagnosed with active chronic periodontitis were included in the study and randomised to either a test (chlorhexidine without alcohol) or control group (chlorhexidine with alcohol). A total of 50 patients were selected for the study. Results: The Wilcoxon Signed Rank test was used to test the difference between the pre-post pair per clinical indicator and Bana-Zyme. The differences between before and after treatment per indicator were significant at P<0.001 for respectively Paroex and Peridex. These values demonstrated the difference between the clinical parameters taken before the treatment and six weeks post treatment. Conclusion: Both mouth wash solutions with and without alcohol had proven to reduce the microbial load as shown by the BANA-Zyme test, with the alcohol containing solution having been more effective.

Dental caries is the most common bacterial disease of humans and occurs when oral bacteria produce acids, following their fermentation of dietary carbohydrates. This acid can then cause a localised demineralisation of the tooth surface. A group of seven species of bacteria, collectively known as the mutans streptococci, have been predominantly implicated in the onset of dental caries. In particular, Streptococcus mutans and Streptococcus sobrinus have been shown to be the main aetiological agents of this disease in humans. Most attempts to control the microbial component of caries target these bacteria. The past 50 years has provided considerable information about the pathogenesis of dental caries, the likely route and time of transmission of cariogenic bacteria to susceptible hosts and possible ways of either treating or controlling the onset of this disease. In regards to the latter, many techniques (such as the use of tooth brushes, mouth washes, dental floss and tooth paste) for the control of plaque build-up exist and the examples listed are generally part of a daily routine. However, these techniques need to be applied regularly, and as such only highly-motivated individuals generally experience improved oral health. Therefore, the search for more effective less labour-intensive approaches continues. One area of research is into the potential application of small ribosomally-synthesised antimicrobial peptides, known as bacteriocins. Bacteriocins generally inhibit closely-related species that occupy the same ecological niche. Their relatively-specific targeting, plus the fact that many are remarkably heat and chemically-stable molecules, makes them excellent candidates for possible anti-caries applications. Numerous bacteriocins produced by the lactic acid bacteria have now been identified. Most can be broadly categorised into one of four main classes, of which Class I, the lantibiotics and Class II, the small (<10 kDa) non-modified peptides, contain the most examples. Many screens for anti-mutans streptococcal (MS) bacteriocins have been carried out and it appears that the best source of anti-MS bacteriocins are the mutans streptococci themselves. Research in this laboratory has identified examples of anti-mutans streptococcal bacteriocins produced by both mutans streptococci and non-mutans streptococci. The present study investigated the anti-MS inhibitors produced by two streptococcal strains, S. mutans N and Streptococcus sanguis K11. During the course of this study a third strain, S. mutans UA159, was also studied for its bacteriocinogenic properties. Although S. sanguis K11 produces anti-mutans streptococcal inhibitory activity, this appears only effective against Streptococcus rattus. In addition however, the inhibitory activity of this strain is also directed against all tested strains of Streptococcus agalactiae and ca. 50% of Streptococcus pyogenes. In the present study a 5069 Da novel inhibitory agent (sanguicin K11) was characterised and shown responsible for this unusual inhibitory spectrum. Through reverse genetics the sanK11 locus was identified and shown to encode a Class II type bacteriocin, the first shown to be produced by S. sanguis. Following screens of additional S. sanguis, sanK11 was shown to be present only in strains producing the same type of inhibitory pattern (P-type) as strain K11. The cysteine residues at positions 7 and 38 of the sanguicin K11 propeptide were shown to form a disulphide bridge essential for sanguicin K11 inhibitory activity. S. mutans N and eight other S. mutans strains have been found to have what appears to be the same inhibitory spectrum, which includes members of the mutans streptococci and several other oral streptococcal species. One strain (UA140) of the eight has previously been shown to produce the lantibiotic mutacin I and the non-lantibiotic mutacin IV. S. mutans N was known to produce the non-lantibiotic mutacin N. The current study set out to investigate how two strains, apparently producing completely different bacteriocins could have the same inhibitory spectrum. Reverse genetics identified the mutacin N structural gene (mutN) and mutagenesis studies showed that this bacteriocin was responsible only for the inhibitory activity against mutans streptococci. Further sequencing around the mutN locus identified a second bacteriocin-like locus (mutO) adjacent to mutN. mutO was also identified to have anti-mutans streptococcal inhibitory activity and because of the close proximity of mutO and mutN and given the homology they share with other known two-peptide bacteriocins it seemed probable that mutacins O and N are components of a new member of this special class of bacteriocins (Class IIb, the two peptide bacteriocins) in which the optimal inhibitory activity is dependent on the co-operative activity of the two peptides. Further investigations of strain N examined the expression of mutacins O and N. During a search for a suitable heterologous non-mutacinogenic S. mutans strain to act as an expression host, the genome reference strain, S. mutans UA159 was given consideration. However, contrary to previous reports, this strain was found to exhibit bacteriocin-like inhibitory activity. During a follow-up investigation, strain UA159 was found to inhibit 84 strains representing 11 different species of bacteria, but no inhibition of mutans streptococci was detected. The locus (nlmAB) encoding the two-peptide bacteriocin mutacin IV was identified within the UA159 genome. Using genetic dissection of nlmA and nlmB, the contribution of each peptide was examined and it was found that only the NlmA* propeptide appears to be active, raising doubts as to whether mutacin IV is a bona fide two-peptide bacteriocin. Deletion of the entire nlmAB locus created a mutant strain that exhibited a loss of inhibitory activity against the same 64 strains as was found for the nlmA mutant. A BLASTP search for the consensus leader sequence that precedes the propeptide of Class II bacteriocins, identified ORFs encoding 9 more putative bacteriocin-like peptides. Further genetic dissection identified the SMU.1914c locus as being responsible for the inhibitory activity against a further 15 strains not already sensitive to mutacin IV. SMU.1914c was renamed mutacin V. However, it appears that another as yet unidentified mutacin(s) is also produced by strain UA159 given that three indicator strains still remained sensitive to a double mutant [UA[Delta](1914/NlmAB)] in which both the mutacin IV and putative mutacin V loci were inactivated. Export of Class II bacteriocins has been found to occur by either a SEC-dependent system or via a dedicated peptide ATP Binding Cassette (ABC) transporter. Three potential ABC transporter ORFs were identified in S. mutans UA159. Two (comA and cslA) had the characteristic accessory factor ORF (comB and cslB respectively) located adjacent to the main ABC transporter ORF, while the third ORF763 appeared to lack this. Mutagenesis of each of these five ORFS was carried out and confirmed cslAB to be the ABC transporter involved in the export of the competence stimulating factor, while the function of ORF763 could not be established in this study. Mutagenesis of either comA or comB resulted in a complete cessation of bacteriocin production by the respective mutant strains. Historically, comA and comB is the nomenclature used for loci encoding the exporter of the competence inducing factors in streptococci. In light of this new information, comA and comB were renamed nlmT and nlmE respectively, to account for the newly defined role of this ABC transporter. The present study investigated four bacteriocins two of which (sanguicin K11 and mutacin ON) appear to have some potential for application to anti-caries control, and the others (mutacins IV and V) being shown to be produced by the genome reference strain (UA159). All three mutacins were shown to be exported from their respective producer cells by the NlmTE ABC transporter, while sanguicin K11 is predicted to be exported by a peptide ABC transporter located adjacent to sanK11. Bacteriocins may yet provide a novel alternative for the treatment and control of dental caries. In their favour is that fact that they have relatively narrow defined inhibitory spectra and thus are unlikely to produce widespread changes to plaque ecosystems. Potential uses include as topical agents where bacteriocin preparations could be incorporated into dentrifices such as toothpastes or mouthwashes. Alternatively, streptococci producing anti-mutans streptococcal bacteriocins could be implanted into the oral cavity in strain replacement therapy strategies. There are pros and cons to each technique and the most effective anti-caries control appears more likely to result from "cocktail therapy" where bacteriocins are combined with a number of other anti-mutans streptococcal agents to achieve long-lasting protection against mutans streptococcus proliferation.

published_or_final_version / Dentistry / Master / Master of Philosophy

Estimation procedures and optimal designs for estimation of the individual parameters and of the global parameters are discussed under various conditions of prior knowledge. The extension to nonlinear parametrization of the response function ís based on the asymptotical validity of the results for the linear parametrization. For the case where the error variance and the dispersion matrix are unknown, an iterative estimation procedure is suggested. An example based on dental plaque pH profiles demonstrates the improvement that is achieved (a) through using the optimal design or a design that ís close to the optimal, and (b) through taking into account prior information. (author's abstract) / Series: Forschungsberichte / Institut für Statistik

<p>Dental plaque is the most important etiological factor of periodontal diseases. Mechanical plaque control is the most effective way in preventing periodontal diseases. Chemical plaque control methods (such as mouthrinses) have been recommended to be used because of some drawbacks in the mechanical methods in some areas of the dentition (such as interproximal areas). But are these mouthrinses really effective in those areas? The aim of this study was to compare the effectiveness of Essential Oils mouthrinse (Listerine) on plaque formation in interproximal areas with Chlorhexidine and Sterile water.</p>

No abstract available