Decontamination of Gutta-percha Cones employed in Endodontics / Descontaminação de cones de guta-percha empregados em endodontia

ABSTRACT The guttapercha cones used in endodontic treatment are produced in aseptic conditions and their composition includes zinc oxide, which is responsible for antibacterial activity. However, there is the possibility of microbial contamination by manipulation, aerosol or during storage. Although several chemical agents have been tested for their decontamination, there is no consensus on the best disinfection protocol to be used. The aim of this study was to evaluate the decontamination of guttapercha cones contaminated with the bacteria Enterococcus faecalis, by using chlorhexidine digluconate (CHX) and sodium hypochlorite (NaClO) at different concentrations for short exposure times. For this purpose, guttapercha cones (size 40) were selected at random from a sealed box and immersed for 1 min in a microbial suspension. Then they were immersed in specific Petri dishes for different groups containing: CHX 2%, NaClO 1% or NaClO 2.5% for 30 s or 1 min, and subsequently placed in tubes containing BHI broth. After incubating the tubes for 48 h, it was observed that 1% and 2.5% NaClO and 2% CHX were effective for decontaminating the cones at those exposure time intervals. Microbial growth was detected in one of the replicates of the group with CHX applied for 30 s. To prevent the possibility of failures at this stage, the exposure time of guttapercha cones to the decontaminating agent should not be reduced.

RESUMO Os cones de gutapercha utilizados no tratamento endodôntico são produzidos em condições assépticas e possuem óxido de zinco em sua composição, responsável pela atividade antibac te riana. No entanto, existe a possibilidade de contaminação microbiana por manipulação, aerossol ou seu armazenamento. Embora vários agentes químicos já tenham sido testados para sua descontaminação, não há consenso sobre o melhor proto colo de desinfecção a ser usado. Nosso objetivo foi avaliar a descontaminação de cones de gutapercha contaminados com a bactéria Enterococcus faecalis, utilizando digluconato de clorexidina (CHX) e hipoclorito de sódio (NaClO) em diferentes concentrações e tempos de exposição curtos. Para esse fim, 40 cones de gutapercha foram selecionados aleatoriamente, de uma caixa selada e imersos por 1 min em uma suspensão microbiana. Em seguida, foram imersos em placas de Petri específicas para diferentes grupos contendo: CHX 2%, NaClO 1% ou 2,5%, nos tempos de exposição de 30s e 1min e subseqüentemente imersos em tubos contendo caldo BHI. Após incubação dos tubos por 48 h, observouse que NaClO 1% e 2,5% e CHX 2% foram eficazes para a descontaminação dos cones nesses intervalos de tempo de exposição. Em uma das réplicas do grupo com CHX aplicado por 30s foi detectado crescimento microbiano. O tempo de exposição dos cones de gutapercha ao agente de desconta minação não deve ser reduzido para evitar a possibilidade de falhas nesse estágio.

Applicability of knowledge of graduates in dentistry: use of irreversible hydrocolloid / Aplicabilidad del conocimiento de licenciados en odontología: el uso de hidrocoloide irreversible

The objective of this study was to evaluate the knowledge applied by dental students on the procedures of disinfection, tempering and pouring of irreversible hydrocolloid impressions. This study was conducted through a questionnaire to 86 undergraduate students, of both genders, of the eighth and ninth period of the School of Dentistry, Pontifical Catholic University, Belo Horizonte, MG. The questionnaire contained 12 multiple choice questions about clinical and laboratory procedures for dental impression. Analyzed data were descriptively and qualitatively. Most subjects (70%) stated they did disinfection of dental impression with 1% sodium hypochlorite spray. However, they did it in open containers (75.4%) and with time control (68.6%). The ratio water / powder is randomly conducted by most students (60.5%), and tap water is the one most commonly used (95.3%). The mixing of the calcium sulfate is done manually by nearly all students (97.7%), and use vibrator during the pouring of the calcium sulfate is common among undergraduates (60.5%). The setting of the calcium sulfate takes place predominantly exposed to air (93%) and the removal of the model is made ??between 30 and 60 min after pouring by 84.9% of students. These results point to the need for awareness of students of adopting practices transmitted during the undergraduate degree. It is also necessary to investigate the possible causes of knowledge transmission problems and how to effectively adopt good clinical practices.

El objetivo fue evaluar el conocimiento aplicado por estudiantes de odontología en los procedimientos de desinfección, templado y vaciado de las impresiones de hidrocoloides irreversibles. Este estudio se llevó a cabo a través de un cuestionario a 86 estudiantes de pregrado, de ambos sexos, del octavo y noveno período de la Escuela de Odontología de la Pontificia Universidad Católica, Belo Horizonte, MG. El cuestionario contenía 12 preguntas de opción múltiple acerca de los procedimientos clínicos y de laboratorio para impresión dental. Los datos fueron analizados de manera descriptiva y cualitativa. La mayoría de los sujetos (70%) declararon que hicieron desinfección de la impresión dental con pulverización de hipoclorito de sodio al 1%. Sin embargo, lo hicieron en recipientes abiertos (75,4%) y con un control de tiempo (68,6%). La relación agua/polvo se realizó de manera aleatoria por la mayoría de los estudiantes (60,5%), utilizando principalmente agua del grifo (95,3%). La mezcla del sulfato de calcio se realiza manualmente por casi todos los estudiantes (97,7%) y el uso del vibrador durante el vertido del sulfato de calcio es común (60,5%). El ajuste del sulfato de calcio tiene lugar predominantemente en exposición al aire (93%), la remoción del modelo se hace entre 30 y 60 min después del vaciado por un 84,9% de los estudiantes. Estos resultados apuntan a la necesidad de que los estudiantes tomen conciencia de las prácticas transmitidas durante la licenciatura. También es necesario investigar las posibles causas de los problemas de transmisión de conocimiento y cómo aplicar efectivamente las buenas prácticas clínicas.

Efficacy of various spray disinfectants on irreversible hydrocolloid impression materials: An in vitro study.

Background: Most of the materials (casts, impressions, etc.) that are sent to the dental laboratories show the presence of numerous pathogenic microorganisms. All the spray disinfectants are not equally effective against these microorganisms. Aims and Objectives: The aim was to compare the effectiveness of different spray disinfectants on irreversible hydrocolloid impressions and to find out the most effective dilution, contact time, and effect against each microorganism studied. Materials and Methods: The effects of four spray disinfectants, 5.25% sodium hypochlorite, 0.525% sodium hypochlorite, 1:213 (1 part in 213 parts of water) povidone iodine, and 2% glutaraldehyde along with control (distilled water) on irreversible hydrocolloid impressions contaminated with Staphylococcus aureus, Bacillus subtilis and Streptococcus viridans were studied. Results: Sodium hypochlorite, 5.25%, showed 1-min exposure time which was able to effect a 4log10 reduction in bacterial counts against S. aureus and S. viridans followed by 0.525% sodium hypochlorite and 2% glutaraldehyde for 10 min. None were able to effect a 4 log10 reduction against B. subtilis. Conclusion: Sodium hypochlorite with a concentration of 5.25% was the most effective disinfectant and required the shortest contact time (1 min). Not all ADA-approved concentrations of surface disinfectants work equally well on irreversible hydrocolloid impression materials.

Comparison of physical and mechanical properties of microwave-polymerized acrylic resin after disinfection in sodium hypochlorite solutions

This study evaluated the color stability, surface roughness and flexural strength of a microwave-polymerized acrylic resin after immersion in sodium hypochlorite (NaOCl), simulating 20 min of disinfection daily during 180 days. Forty disk-shaped (15 x 4 mm) and 40 rectangular (65 x 10 x 3 mm) specimens were prepared with a microwave-polymerized acrylic resin (Onda-Cryl). Specimens were immersed in either 0.5 percent NaOCl, 1 percent NaOCl, Clorox/Calgon and distilled water (control). Color measurements were determined by a portable colorimeter. Three parallel lines, separated by 1.0 mm, were registered on each specimen before and after immersion procedures to analyze the surface roughness. The flexural strength was measured using a 3-point bending test in a universal testing machine with a 50 kgf load cell and a crosshead speed of 1 mm/min. Data were analyzed statistically by ANOVA and Tukey's test (?=0.05). There was no statistically significant differences (p>0.05) among the solutions for color, surface roughness and flexural strength. It may be concluded that immersion in NaOCl solutions simulating short-term daily use during 180 days did not influence the color stability, surface roughness and flexural strength of a microwave-polymerized acrylic resin.

Este estudo avaliou a estabilidade de cor, rugosidade superficial e resistência à flexão de resina acrílica polimerizada por microondas após desinfecção em hipoclorito de sódio, simulando 20 min de desinfecção diária durante 180 dias. Quarenta espécimes circulares (15 x 4 mm) e 40 retangulares (65 x 10 x 3 mm) foram preparados em resina acrílica polimerizada por microondas (Onda-Cryl). As amostras foram imersas em hipoclorito de sódio a 0,5 por cento, hipoclorito de sódio a 1 por cento, Clorox/Calgon e água destilada (controle). Medidas de cor foram determinadas por um espectrocolorímetro portátil. Três linhas paralelas, separadas por 1,0 mm, foram registradas em cada amostra antes e depois dos procedimentos de imersão para analisar a rugosidade superficial. A resistência à flexão foi medida utilizando um teste de flexão por 3 pontos em uma máquina universal de ensaios com uma célula de carga de 50 Kgf e uma velocidade de 1 mm/min. Os dados foram analisados estatisticamente por ANOVA e teste de Tukey (?=0,05). Não houve diferença estatisticamente significante (p>0,05) entre as soluções para cor, rugosidade superficial e resistência à flexão. Pode-se concluir que a imersão em soluções de hipoclorito de sódio, simulando um uso diário de curta duração durante 180 dias, não influenciou a estabilidade de cor, rugosidade superficial e resistência à flexão de resina acrílica polimerizada por microondas.

Maximum inhibitory dilution of mouthwashes containing chlorhexidine and polyhexamethylene biguanide against salivary staphylococcus aureus

OBJECTIVE: The aim of the present study was to determine the in vitro maximum inhibitory dilution (MID) of two chlorhexidinebased oral mouthwashes (CHX): Noplak®, Periogard®, and one polyhexamethylene biguanide-based mouthwash (PHMB): Sanifill Premium® against 28 field Staphylococcus aureus strains using the agar dilution method. MATERIALS AND METHODS: For each product, decimal dilutions ranging from 1/10 to 1/655,360 were prepared in distilled water and added to Mueller Hinton Agar culture medium. After homogenization, the culture medium was poured onto Petri dishes. Strains were inoculated using a Steers multipoint inoculator and dishes were incubated at 37ºC for 24hours. For reading, MID was considered as the maximum dilution of the mouthwash still capable of inhibiting microbial growth. RESULTS: Sanifill Premium® inhibited the growth of all strains at 1/40 dilution and of 1 strain at 1/80 dilution. Noplak® inhibited the growth of 23 strains at 1/640 dilution and of all 28 strains at 1/320 dilution. Periogard® showed inhibited growth of 7 strains at 1/640 dilution and of all 28 strains at 1/320 dilution. Data were submitted to Kruskal-Wallis statistical test, showing significant differences between the mouthwashes evaluated (p<0.05). No significant difference was found between Noplak® and Periogard® (p>0.05). Sanifill Premium® was the least effective (p<0.05). CONCLUSION: It was concluded that CHX-based mouthwashes present better antimicrobial activity against S. Aureus than the PHMB-based mouthwash.

Comparative study of the antimicrobial efficacy of chlorhexidine gel, chlorhexidine solution and sodium hypochlorite as endodontic irrigants

The purpose of this study was to assess the in vitro the antimicrobial efficacy of chlorhexidine gluconate gel as an endodontic auxiliary chemical substance compared to sodium hypochlorite (NaOCl) and chlorhexidine gluconate solution. The antimicrobial efficacy of the tested substances was evaluated using the agar diffusion test. The growth inhibition zones produced by 0.2 percent, 1 percent and 2 percent chlorhexidine gel were evaluated against 5 facultative anaerobic bacteria and 4 pigmented Gram-negative anaerobes, and compared to the results obtained by NaOCl and chlorhexidine solution. The largest growth inhibition zones were produced when the test bacteria were in contact with 2 percent chlorhexidine gluconate gel (11.79 mm), being significantly different (p<0.05) from the growth inhibition zones produced by all NaOClconcentrations, including 5.25 percent (9.54 mm). However, there was no statistically significant difference (p>0.05) between the growth inhibition zones obtained with equal concentrations of chlorhexidine solution and gel. The results of this study indicate that, as far as its antimicrobial properties are concerned, chlorhexidine gel has a great potential to be used as an endodontic auxiliary chemical substance.

O objetivo deste estudo foi avaliar in vitro a atividade antimicrobiana do gluconato de clorexidina gel, como irrigante endodôntico, comparando-o ao hipoclorito de sódio (NaOCl) e ao gluconato de clorexidina líquido. A atividade antimicrobiana das substâncias testadas foi avaliada pelo teste de difusão em ágar. As zonas de inibição de crescimento bacteriano produzidas pela clorexidina gel a 0,2 por cento; 1 por cento e 2 por cento foram observados frente a 5 espécies de bactérias anaeróbias facultativas e 4 espécies de anaeróbios estritos, Gram-negativos e produtores de pigmento negro; e comparados com os resultados obtidos pelo NaOCl e pela clorexidina líquida. As maiores zonas de inibição foram produzidas quando as bactérias testadas ficaram em contato com a clorexidina a 2 por cento em gel (11,79 mm), apresentando diferença estatisticamente significante (p<0,05) quando comparados às zonas de inibição de crescimento bacteriano produzidas por todas as concentrações avaliadas de NaOCl, incluindo 5,25 por cento (9,54 mm). No entanto, não houve diferença estatisticamente significante (p>0,05) comparando as zonas produzidas por concentrações equivalentes de clorexidina líquida ou gel. Os resultados indicaram que a clorexidina em gel tem grande potencial para ser usada como substância química auxiliar quanto às suas propriedades antimicrobianas.

AIDS em odontopediatria: uma realidade atual / AIDS in pedodontics: today reality

Os autores relatam através da literatura, a questäo da AIDS, especialmente na infância, e medidas de biossegurança para o exercício da profissäo, em decorrência do caso de uma criança com 3 anos de idade, que compareceu à clínica odontológica para um tratamento dentário, cuja queixa principal era de dor. No início do tratamento, ela se apresentou com um quadro de saúde geral precário com gripes repetitivas, otite crônica, febre intermitente, queilite angular, rachaduras peribucais e também com cárie rompante. Foi encaminhada para tratamento médico, com resposta muito satisfatória para o estado geral. Cerca de 1 ano após, os familiares tiveram ciência de que a criança tinha AIDS. O objetivo deste estudo é alertar os odontopediatras para a AIDS na Odontopediatria e para a importância do respeito às normas de biossegurança