Coronal microleakage of endodontically treated teeth with intracanal post exposed to fresh human saliva

OBJECTIVE: The aim of this study was to investigate the coronal microleakage of endodontically treated teeth prepared to receive an intracanal post and teeth with an intracanal post but without a prosthetic crown and exposed to contamination by fresh human saliva. MATERIAL AND METHODS: A mechanical-chemical preparation following the step-back technique was carried out in 35 extracted single-rooted human teeth. The teeth were randomly divided into five groups: G1=root canals instrumented, obturated, and prepared to receive an intracanal post (N=10); G2=root canals with cemented posts but without coronal sealing (N=10); PC1=positive control root canals instrumented and open (N=5); PC2=positive control 2 root canals without instrumentation and open (N=5); and NC=negative control healthy teeth (N=5). The crowns were removed except for the control group of intact teeth. The root canals were obturated and sterilized with cobalt 60 gamma irradiation and were then adapted in an apparatus using a Brain Heart Infusion (BHI) medium and fresh human saliva for contamination. Microbial growth was indicated by the presence of turbidity in the BHI liquid medium. RESULTS: Data were submitted to the Kaplan-Meier Survival Analysis and the Holm-Sidak statistic method, which observed an index of 90% of microleakage in root canals after 24 hours for G1 and 70% of microleakage in samples at the end of 40 days for G2. CONCLUSION: The results show that root canals with an intracanal post but without a prosthetic crown can be recontaminated when exposed to fresh human saliva in a short period. .

Aspectos microbiológicos da cárie dental / Microbiological aspects of dental cavities

A cárie é uma doença infecto-contagiosa, de caráter crônico e multifatorial. Sabe-se da indispensabilidade de microrganismos na superfície dental para que tenhamos o desenvolvimento da doença cárie, porém só a presença deles não é o bastante. Fatores como higiene, hábitos alimentares, colonização bacteriana, composição da saliva, entre outros, influenciam o metabolismo das bactérias sobre os dentes, modulando a atividade da cárie. Até a década de 60, os Lactobacilos eram tidos como os principais agentes etiológicos. Entretanto, quando mais informações sobre a composição microbiana do biofilme foram obtidas, observou-se que os Lactobacilos constituem apenas uma pequena fração de sua composição. Atualmente sabe-se que esses microrganismos são mais uma conseqüência do que causa do processo de iniciação da doença. O S. mutans, após sua redescoberta em 1960 por Fitzgerald e Keyes, tem sido, conforme relata a literatura, apontado como a principal bactéria em relação à etiologia da cárie. Entre as espécies incluídas nos Estreptococos do Grupo Mutans (EGM), o S. mutans e S. sobrinus apresentam potencial cariogênico em humanos. Os trabalhos indicam a diversidade de microrganismos que habitam a superfície dentária, existindo no mínimo quatro diferentes tipos de cáries. Este artigo tempor objetivo, fazer uma revisão sobre os principais aspectos microbiológicos envolvidos com a cárie dental.

Dental caries is an infectious-contagious disease that has a chronic multifactorial pattern. It is known that the presence of microrganisms on dental surface is essential for the development of caries disease, despite only their presence is not e nough. Factors such as hygiene, alimentary habits, bacterial colonisation, and saliva composition, among others, influence the metabolism of bacteria on the teeth, modulating caries activity. Until 1960, Lactobacillus were regarded as the main etiological agents. However, when more information about the microbiological composition of the biofilm was obtained, it was observed that Lactobacillus constitute only a small fraction of its composition. Currently, it is known that these microrganisms are rather a consequence than a cause of the initiating process of the disease. According to literature reports, the S. mutans, after being rediscovered by Fitzgerald e Keyes in 1960, has been pointed out as the main bacteria related to caries etiology. Among the species included in Mutans Streptococci Group (MSG),S. mutans and S. sobrinus have a cariogenic potential in humans. Research indicate the diversity of the microrganisms hosted on dental surface, there being at least four different types of caries. The purpose of this paper is to review the major microbiological aspects involved in dental caries.