Biofilms of black tooth stains: PCR analysis reveals presence of Streptococcus mutans

This study investigated the presence of the black-pigmented bacteria Prevotella nigrescens and Prevotella intermedia, the non-black-pigmented bacteria Actinomyces spp and particularly the cariogenic pathogen Streptococcus mutans in the dental biofilms of patients with or without black extrinsic tooth stains, using the multiplex polymerase chain reaction (PCR) technique. Analysis of the dental biofilms of patients with (n=26) or without (n=26) black tooth stains was performed using duplex PCR for the 16S ribosomal RNA gene (P. nigrescens, P. intermedia, Actinomyces spp) and glucosyltransferase-I gene for S. mutans. P. nigrescens and S. mutans were the most frequent bacteria detected in both groups. The least frequently detected were P. intermedia and Actinomyces spp. The similar bacterial composition of dental biofilms of black tooth stains and healthy tooth surfaces indicates that black tooth stains are not free of cariogenic bacteria.

O objetivo deste estudo foi investigar a presença das bactérias pigmentadoras de negro Prevotella nigrescens e Prevotella intermedia, da não pigmentadora de negro Actinomyces spp e particularmente a bactéria cariogênica Streptococcus mutans, no biofilme dentário de pacientes com ou sem manchas dentárias extrínsecas negras, utilizando a técnica multiplex PCR (reação em cadeia da polimerase). Análises do biofilme dentário de pacientes com manchas (n=26) e sem manchas (n=26) foram realizadas utilizando a multiplex PCR para o gene 16S RNA ribosomal (P. nigrescens, P. intermedia, Actinomyces spp) e o gene glucosiltransferase-I para S. mutans. P. nigrescens e S. mutans foram as bactérias mais frequentemente detectadas em ambos os grupos. As menos frequentemente detectadas foram P. intermedia e Actinomyces spp. A similaridade entre a composição bacteriana dos biofilmes dentários das manchas dentárias extrínsecas negras e das superfícies dentárias sem manchas indicam que as manchas dentárias extrínsecas negras não estão livres de bactérias cariogênicas.

Un enfoque actual sobre la relevancia de las pigmentaciones extrínsecas / Current approach to the relevance of extrinsic stains

Las manchas extrínsecas negras son consideradas un tipo especial de placa calcificada y pueden aparecer en dientes temporarios alrededor de los 2 ó 3 años de edad. Se extienden en forma paralela al margen gingival y pueden presentarse como puntos aislados o líneas continuas, principalmente sobre las caras libres.De acuerdo a investigaciones recientes, en la formación de estos depósitos estaría involucrado el ActinobacillusActinomycetemcomitans; mientras que desde el punto de vista bioquímico se encontró una elevada concentración de iones calcio y fosfato que disminuirían la solubilidad del esmalte.La presente revisión tuvo por objetivo recopilar y exponer los estudios publicados acerca las pigmentaciones extrínsecas negras, su etiología, prevalencia y relación con la baja incidencia de caries.

Black tooth stains are considered a specific type of calculus formation that may appear in deciduous dentition between the age of 2 to 3 years old. Characterized by dark dots or lines localized parallel to the gingival margin, mainly on clean tooth surfaces.Recent research studies suggest that Actinobacillus Actinomycetemcomitans plays an important role in the formation of these deposits; from a biochemical point of view it was found that high calcium and phosphate ion concentrations in saliva reducesenamel solubility. The aim of this review was to collect and analyze published studies on extrinsic tooth discoloration, its etiology, prevalence andrelation to low caries incidence.

Microbiological and microscopic analysis of the pulp of non-vital traumatized teeth with intact crowns

OBJECTIVE: This study evaluated the presence of microorganisms and analyzed microscopically the pulp of 20 traumatized human teeth with intact crowns and clinical diagnosis of pulp necrosis, based on the association of at least three of the clinical criteria: crown discoloration, negative response to thermal and electric pulp vitality tests, positive response to vertical and horizontal percussion, pain on palpation or mobility. MATERIAL AND METHODS: Microbiological collection was performed from the root canals to evaluate the presence of microorganisms. The pulp samples were stained with hematoxylin and eosin (H.E.) for histological evaluation of possible morphological alterations. RESULTS: Analysis of results was performed by statistical tests (linear regression test and diagnostic analysis) and subjective analysis of the sections stained with H.E. and revealed that only 15 percent of the sample did not exhibit microbial development. The time elapsed between dental trauma and onset of endodontic intervention ranged from 15 days to 31 months; the percussion test presented high sensitivity (80 percent) for detection of microorganisms in the root canal of traumatized teeth; 3 teeth (15 percent) did not present pulp tissue, being characterized as complete autolysis; analysis of pulp samples was performed on the other 17 cases, among which 3 (15 percent) exhibited partial necrosis without possibility of repair and 14 presented complete necrosis; none of the clinical criteria employed for the diagnosis of pulp necrosis in traumatized teeth was pathognomonic. CONCLUSIONS: The present results allowed the following conclusions: with regard to microbiological findings, 85 percent of teeth presented microorganisms in the root canal, despite the presence of an intact crown. Concerning the microscopic findings, 100 percent of traumatized teeth presented pulp necrosis; the pulp vitality tests based on pulp response to heat, cold and vertical percussion ...