Effect of thermal and acid challenges on the surface properties of pink restorative materials.

PURPOSE: To compare the effect of thermal cycling and erosive challenge on color change, surface roughness, surface loss and biofilm deposition of three resin-based composites. METHODS: Three resin-based composites that reproduce the color of gingival tissues [two nanohybrid composites (A and B) and a giomer (C) ] were tested before and after distinct challenges [ thermal cycling (TC) and erosive challenge (EC) ] in regard to its color stability, surface roughness, surface loss and biofilm deposition. Surface roughness and surface loss specimens (n=10) were measured with an optical profilometer and, color stability (n=10) was measured with a spectrophotometer. Biofilm deposition (n=5) was measured after 3 and 24 hours by safranin staining. RESULTS: Two-way ANOVA test was performed to analyze color change, roughness and surface loss. A significant color change was detected for resin-based composites (P< 0.05) and its interaction with tested challenges (P< 0.05). The highest color variation was observed on the giomer after erosive challenge. Surface loss was not different between tested groups (P= 0.708). The roughness was significantly higher in specimens submitted to thermal cycling (P> 0.05). For biofilm quantification, after 3 and 24 hours, ANOVA (3-way) detected significance for the interaction of challenges and resin-based composites (P< 0.05 and P< 0.05, respectively). All resin-based composites presented color changes after challenges; higher roughness was observed after thermal cycling for all resin-based composites tested, without significant surface loss; and higher biofilm deposition was observed on the giomer samples when submitted to erosive challenge after 3 and 24 hours. CLINICAL SIGNIFICANCE: Pink esthetic is as important as dental esthetics and some restorative materials can mimic gingival tissue. However, the tested giomer must be indicated with caution, since it presented significant changes after thermal and acid challenges.

Optical coherence tomography and polarized light microscopy for the evaluation of artificial caries: a preliminary study.

This study was designed to investigate whether there is a correlation between the findings of optical coherence tomography (OCT) and polarized light microscopy (PLM) when these techniques are used to evaluate standard enamel white-spot lesions developed by distinct cariogenic challenges. Bovine enamel fragments (N = 168) were randomly allocated into 6 experimental groups according to the microbiologic model (Streptococcus mutans UA159, Streptococcus sobrinus ATCC 33478, or mixed S mutans and S sobrinus) and carbohydrate sources (1% sucrose or combined 1% sucrose and 1% starch). Specimens were examined by OCT and PLM every day within a period of 7 days. Five measurements of demineralization depth were recorded for each specimen, and means were calculated. Data were analyzed with analysis of variance and Tukey tests (α = 0.05), and a correlation test was performed. All cariogenic challenges created sub-superficial lesions. In both the OCT and PLM analyses, the demineralization depth reached its peak between days 6 and 7 of the cariogenic challenge, except for the group challenged with S sobrinus supplemented with combined sucrose and starch; for that group, demineralization peaked on day 5 in the OCT analysis. There was a significant correlation between OCT and PLM (P = 0.00; r = 0.842). This preliminary study suggests that OCT is a reliable, nondestructive method to measure the demineralization depth of enamel white-spot lesions, which can be useful for the laboratory and has potential for clinical studies. Using the 1% sucrose and S mutans model for 6 days is a simple and effective method to induce enamel caries-like lesions without compromising the depth and morphologic features of the obtained lesions.

Intraspecies Variability Affects Heterotypic Biofilms of Porphyromonas gingivalis and Prevotella intermedia: Evidences of Strain-Dependence Biofilm Modulation by Physical Contact and by Released Soluble Factors.

It is well known that strain and virulence diversity exist within the population structure of Porphyromonas gingivalis. In the present study we investigate intra- and inter-species variability in biofilm formation of Porphyromonas gingivalis and partners Prevotella intermedia and Prevotella nigrescens. All strains tested showed similar hydrophobicity, except for P. gingivalis W83 which has roughly half of the hydrophobicity of P. gingivalis ATCC33277. An intraspecies variability in coaggregation of P. gingivalis with P. intermedia was also found. The association P. gingivalis W83/P. intermedia 17 produced the thickest biofilm and strain 17 was prevalent. In a two-compartment system P. gingivalis W83 stimulates an increase in biomass of strain 17 and the latter did not stimulate the growth of P. gingivalis W83. In addition, P. gingivalis W83 also stimulates the growth of P. intermedia ATCC25611 although strain W83 was prevalent in the association with P. intermedia ATCC25611. P. gingivalis ATCC33277 was prevalent in both associations with P. intermedia and both strains of P. intermedia stimulate the growth of P. gingivalis ATCC33277. FISH images also showed variability in biofilm structure. Thus, the outcome of the association P. gingivalis/P. intermedia seems to be strain-dependent, and both soluble factors and physical contact are relevant. The association P. gingivalis-P. nigrescens ATCC33563 produced larger biomass than each monotypic biofilm, and P. gingivalis was favored in consortia, while no differences were found in the two-compartment system. Therefore, in consortia P. gingivalis-P. nigrescens physical contact seems to favor P. gingivalis growth. The intraspecies variability found in our study suggests strain-dependence in ability of microorganisms to recognize molecules in other bacteria which may further elucidate the dysbiosis event during periodontitis development giving additional explanation for periodontal bacteria, such as P. gingivalis and P. intermedia, among others, to persist and establish chronic infections in the host.

Antimicrobial photodynamic therapy: a promise candidate for caries lesions treatment.

BACKGROUND: Antibacterial photodynamic therapy (aPDT) is a promising adjunctive therapy to the treatment of caries lesions, mainly in the minimally invasive approach to preserve dental tissue and favor its repair. Here we analyzed both the efficacy of aPDT in reducing the bacterial load in cariogenic biofilms and the indirect effect of noxious components produced by aPDT on the viability of dental pulp cells. METHODS: The aPDT protocol was established using 0.025g/mL methylene blue (MB) and 5min pre-irradiation time. A continuous-wave diode laser (660nm, 0.04cm(2) spot size, 40mW, 60s, 60J/cm(2) and 2.4J) was used in punctual and distance modes to excite the MB. The protocol was first tested against Streptococcus mutans (U159) biofilms produced in 96-well microplates, and then evaluated on caries-like affected human dentin discs of three thicknesses. The number of colony forming units (CFU) was compared between groups. Discs were then assembled in metallic inserts to produce an artificial pulp chamber and allow investigation of the indirect effects of aPDT on dental pulp cells by the 3-(4,5-dimethylthiazol-2-yl)-diphenyltetrazolium bromide (MTT) assay. Data were analyzed using Student's t test or one-way analysis of variance (ANOVA) followed by the Tukey's test at a significance level of 5%. RESULTS: Bacterial load reduction was observed in biofilms produced both in the microplates (p<0.05) and on the caries-like affected dentin discs (81.01% or mean reduction of log21.010±0.1548; p=0.0029). The cell viability of aPDT and control group was similar (p>0.05). CONCLUSIONS: aPDT may be considered a promise adjunctive therapy for deep carious lesions.

Differential transcription of virulence genes in Aggregatibacter actinomycetemcomitans serotypes.

BACKGROUND: Aggregatibacter actinomycetemcomitans serotypes are clearly associated with periodontitis or health, which suggests distinct strategies for survival within the host. OBJECTIVE: We investigated the transcription profile of virulence-associated genes in A. actinomycetemcomitans serotype b (JP2 and SUNY 465) strains associated with disease and serotype a (ATCC 29523) strain associated with health. DESIGN: Bacteria were co-cultured with immortalized gingival epithelial cells (OBA-9). The adhesion efficiency after 2 hours and the relative transcription of 13 genes were evaluated after 2 and 24 hours of interaction. RESULTS: All strains were able to adhere to OBA-9, and this contact induced transcription of pgA for polysaccharide biosynthesis in all tested strains. Genes encoding virulence factors as Omp29, Omp100, leukotoxin, and CagE (apoptotic protein) were more transcribed by serotype b strains than by serotype a. ltxA and omp29, encoding the leukotoxin and the highly antigenic Omp29, were induced in serotype b by interaction with epithelial cells. Factors related to colonization (aae, flp, apaH, and pgA) and cdtB were upregulated in serotype a strain after prolonged interaction with OBA-9. CONCLUSION: Genes relevant for surface colonization and interaction with the immune system are regulated differently among the strains, which may help explaining their differences in association with disease.

Evaluation of caries-affected dentin with optical coherence tomography.

The purpose of this study was to evaluate the degree of demineralization of artificially induced caries-affected human dentin by an in vitro microbiological method. The occlusal surfaces of 6 human molar teeth were abraded until a flat surface was obtained, and the enamel was removed to expose the occlusal dentin surface. These teeth were sectioned in 12 halves in the vestibular-lingual direction and divided into 3 groups according to the period length of the microbiological essay (n = 4): G1, 7 days; G2, 14 days; and G3, 21 days. The surfaces of all specimens were protected by an acid-resistant nail varnish, except for a window where the caries lesion was induced by a Streptoccocus mutans biofilm in a batch-culture model supplemented with 5% sucrose. The specimens were then analyzed by optical coherence tomography (OCT) with a super-luminescent light diode (Λ = 930 nm) with 6.0-µm lateral and longitudinal resolution (in the air). Qualitative and quantitative results (images and average dentin demineralization, respectively) were obtained. The mean demineralization depths were (µm) 235 ± 31.4, 279 ± 14, and 271 ± 8.3 in groups 1, 2, and 3, respectively. In addition, no significant change was observed in the lesion mean depth from 7 days of cariogenic challenge on. In conclusion, OCT was shown to be an efficient and non-invasive method to detect the depths of lesions caused by demineralization. Further, a seven-day demineralization time was considered sufficient for caries-affected dentin to be obtained.

Evaluation of caries-affected dentin with optical coherence tomography

The purpose of this study was to evaluate the degree of demineralization of artificially induced caries-affected human dentin by an in vitro microbiological method. The occlusal surfaces of 6 human molar teeth were abraded until a flat surface was obtained, and the enamel was removed to expose the occlusal dentin surface. These teeth were sectioned in 12 halves in the vestibular-lingual direction and divided into 3 groups according to the period length of the microbiological essay (n = 4): G1, 7 days; G2, 14 days; and G3, 21 days. The surfaces of all specimens were protected by an acid-resistant nail varnish, except for a window where the caries lesion was induced by a Streptoccocus mutans biofilm in a batch-culture model supplemented with 5 percent sucrose. The specimens were then analyzed by optical coherence tomography (OCT) with a super-luminescent light diode (Λ = 930 nm) with 6.0-µm lateral and longitudinal resolution (in the air). Qualitative and quantitative results (images and average dentin demineralization, respectively) were obtained. The mean demineralization depths were (µm) 235 ± 31.4, 279 ± 14, and 271 ± 8.3 in groups 1, 2, and 3, respectively. In addition, no significant change was observed in the lesion mean depth from 7 days of cariogenic challenge on. In conclusion, OCT was shown to be an efficient and non-invasive method to detect the depths of lesions caused by demineralization. Further, a seven-day demineralization time was considered sufficient for caries-affected dentin to be obtained.

Avaliação da atividade antimicrobiana de adesivo ortodôntico associado a verniz de clorexidina e timol na colagem de braquetes / Evaluation of antimicrobial activity of orthodontic adhesive associated with chlorhexidine-thymol varnish in bracket bonding

OBJETIVO: avaliar a atividade antimicrobiana da associação de um adesivo ortodôntico com um verniz de clorexidina e timol. MÉTODOS: foram utilizados 32 pré-molares humanos divididos em 4 grupos. O grupo 1 consistiu do grupo controle, no qual o adesivo utilizado para a colagem do braquete não estava associado a nenhum agente antimicrobiano. Os grupos 2, 3 e 4 foram colados com um sistema adesivo associado a um verniz de clorexidina e timol. Os grupos 3 e 4 foram armazenados em água por 7 dias e 30 dias, respectivamente, enquanto os corpos de prova do grupo 2 foram, logo depois da colagem, colocados em ágar semeado com Streptococcus mutans por 48h a 37ºC. RESULTADOS: os grupos experimentais, com exceção do grupo controle, apresentaram atividade antimicrobiana com tendência de redução do seu potencial de ação com maior tempo de imersão em água. CONCLUSÃO: a associação do verniz de clorexidina a um sistema adesivo utilizado em Ortodontia apresenta-se vantajosa pela sua atividade antimicrobiana.

OBJECTIVE: To assess the antimicrobial activity resulting from the association of an orthodontic adhesive with chlorhexidine-thymol varnish. METHODS: Thirty-two extracted human premolars were used, divided into four groups. In Group 1, the control group, the adhesive used to bond the bracket was not associated with any antimicrobial agent. Groups 2, 3 and 4 were bonded with an adhesive system associated with chlorhexidine-thymol varnish. Groups 3 and 4 were stored in water for 7 days and 30 days, respectively, while the specimens from group 2 were, soon after bonding, placed on agar seeded with Streptococcus mutans for 48 hours, at 37º C. RESULTS: The experimental groups, with the exception of the control group, showed antimicrobial activity whose action tended to decline commensurately with the amount of time that they remained immersed in water. CONCLUSIONS: The association of chlorhexidine-thymol varnish with an adhesive system used in orthodontics proved to be advantageous due to its antimicrobial activity.

Evaluation of three different adhesive systems using a bacterial method to develop secondary caries in vitro.

PURPOSE: To assess the effects of three different dental adhesive systems on the formation of secondary root caries, in vitro, with a standardized interfacial gap in a filled cavity model. METHODS: 40 sound human molars were selected and randomly assigned to four experimental groups: Clearfil SE Bond (CSEB), Xeno III (X-III), Scotchbond Multi-Purpose Plus (SBMP) and negative control (NC) without an adhesive system. After the standardized Class V cavity preparations on the buccal and lingual surfaces, restorations were placed with resin composite (Filtek Z250) using a standardized interfacial gap, using a 3 x 2 mm piece of 50 microm metal matrix. The teeth were sterilized with gamma irradiation and exposed to a cariogenic challenge using a bacterial system with Streptococcus mutans. Depth and extension of wall lesions formed and the depth of outer lesions were measured by software coupled with light microscopy. RESULTS: For wall lesion extension the ANOVA test showed differences between groups except between X-III and SBMP (P=0.294). The Tukey's test of confidence intervals indicated smaller values for the CSEB group than for the others. For wall lesion depth the CSEB group also presented the smallest mean values of wall lesion depth when compared to the others (P<0.0001) for all comparisons using Tukey's test. Regarding outer lesion depth, all adhesives showed statistically similar behavior. SEM evaluation of the morphologic appearance of caries lesions confirmed the statistical results showing small caries lesion development for cavities restored with CSEB adhesive system, which may suggest that this adhesive system interdiffusion zone promoted a good interaction with subjacent dentin protecting the dental tissues from recurrent caries.

High-power diode laser in the disinfection in depth of the root canal dentin.

OBJECTIVE: The objective of this study was to evaluate the disinfection degree of dentine caused by the use of diode laser after biomechanical procedures. STUDY DESIGN: Thirty teeth were sectioned and roots were autoclaved and incubated for 4 weeks with a suspension of Enterococcus faecalis. The specimens were randomly divided into 3 groups (n = 10): G1, instrumented with rotary files, irrigated with 0.5% sodium hypochlorite and 17% EDTA-T, and then irradiated by 830-nm diode laser at 3 W; G2, the same procedures as G1 but without laser irradiation; and G3, irrigation with saline solution (control). Dentin samples of each third were collected with carbide burs and aliquots were sowed to count viable cells. RESULTS: The disinfection degree achieved was 100% in G1 and 98.39% in G2, when compared to the control group (G3). CONCLUSION: Diode laser irradiation provided increased disinfection of the deep radicular dentin in the parameters and samples tested.

Avaliação da desinfecção da dentina radicular em profundidade provocada pela irradiação do laser de diodo de alta potência / Evaluation of roof canal dentin desinfection in depth caused by high power diode laser irradiation

Dentre os microorganismo isolados nos casos de insucesso, o Enterococcus faecalis é comumente encontrado. A irradiação laser apresenta características antimicrobianas que podem auxiliar no tratamento endodôntico. Este estudo tem por objetivo avaliar o grau de descontaminação provocado pelo uso do laser de diodo de alta potência na dentina radicular em profundidade, após preparo químico-cirúrugico in vitro. Utilizaram-se 30 raízes de dentes unirradiculares esterelizadas em autoclave, as quais foram inoculadas por E. faecalis durante 4 semanas e divididas em 3 grupos. Grupo 1: instrumentação rotatória com hipoclorito de sódio 0,5% e creme Endo PTC, irrigação com EDTA-T 17% e posterior irradiação com laser de diodo de alta potência por 5 segundos com 4 repetições, na potência de 3W; Grupo 2: instrumentação com Grupo 1, sem irradiação; e Grupo 3: apenas irrigação com 20 mL de solução fisiológica estéril. Os espécimes tiveram suas paredes dentinárias desgastadas e as raspas, bem como o cilindro externo restante de dentina, foram imersoso em 1 mL de água peptonada. Assim, alíquotas foram semeadas em meio mEnterococcus. Os resultados foram tratados estatisticamente pelo teste Kruskal-Wallis com método de comparação Dunn e apresenta diferenças significantes entre os grupos (p<0,05). Em porcentagens, a redução da contaminação provocada pelo Grupo 1 foi de 100% e pelo Grupo 2, de 98,39%, ambas em relação ao Grupo 3 (controle). A irradiação do laser de diodo nos parâmetros e amostras testadas foi eficaz na redução da contaminação em profundidade da dentina radicular frente ao Enterococccus faecalis.

Antibacterial activity of glass-ionomer cement containing antibiotics on caries lesion microorganisms.

PURPOSE: To assess the total viable bacteria in infected dentin after sealing with glass-ionomer cement containing 1% metronidazole, 1% ciprofloxacin and 1% cefaclor. METHODS: 40 children were selected, with ages ranging from 4-10 years, with primary teeth with active carious lesions without any pulpal involvement. The patients were divided randomly into two groups in accordance to the glass-ionomer cement used to seal the carious lesions: Group 1 (control, n=20), sealing with conventional glass-ionomer cement; and Group 2 (test, n=20) sealing with glassionomer cement including antibiotics. The infected dentin was collected both before and 24 hours after the sealing of the cavities and, after inoculation in blood agar, all the plates were incubated in containers kept at 37 degrees C for 5 days in an atmosphere of 85% N2, 10% CO2 and 5% H2, for subsequent counting of total viable bacteria. RESULTS: The results were analyzed using the Wilcoxon and Mann-Whitney tests. The glass-ionomer cement with 1% of metronidazole, 1% of ciprofloxacin and 1% of cefaclor showed a significantly greater reduction in microbiota in the infected dentin in comparison to the reduction with the conventional ionomer cement (P< 0.01), with a mean reduction of 98.65% of all viable bacteria. The infected dentin after sealing with glass-ionomer cement with antibiotics showed, using scanning electron microscopy, the presence of bacterial aggregates, intertubular dentin with exposure of collagen fibers, and dentin tubules.

Sports dentistry: buccal and salivary profile of a female soccer team.

Sports dentistry has been considered a prominent area of dentistry because dental health can limit the abilities of athletes, both professional and nonprofessional, in their training and competition. Dental decay is associated with the frequent use of carbohydrates, recommended as an energy source for exercise. Strong indications exist regarding the possibility to use saliva as a performance determinant and for evaluation and prescription of physical activity. This study evaluated the salivary profiles (pH, flow rate, mutans streptococci and Lactobacillus counts) and decayed, missing, and filled teeth of 18 female soccer players (13 to 19 years old) of the Olympic Training and Research Center of São Paulo, before and after a training session. The salivary flow rate presented a significant reduction after training; however, there was no significant alteration in pH. Fifty percent of the players presented 10(5) to 10(6) mutans streptococci, and 66% presented 10(3) Lactobacillus. Several salivary components protect against microorganisms that cause superior respiratory tract infections (common in athletes), as well as participating in the remineralization mechanism during cariogenic challenges. Thus, due to the salivary flow rate reduction in this population with a high number of cariogenic microorganisms, noncariogenic drink ingestion at regular intervals and maintenance of hydration levels during training, are suggested.

Oral conditions in children with cerebral palsy.

PURPOSE: Cerebral palsy (CP) is a major severe childhood disability and its prevalence is increasing, particularly among premature low-weight newborns. The oral conditions observed demonstrate the need for home and professional care for these individuals. This study aimed to investigate dental caries, plaque index, time of eruption, malocclusion, bruxism and motor oral skills in a group of 62 CP children (study group). METHODS: The results were compared to those obtained for a control group with 67 normal children. Nonparametric statistical tests including the Mann-Whitney test, Fisher's Exact test (P), Chi-square test (chi2), and Cochran's Q test were used according to the nature of the variables studied, with the level of significance set at P<.05. RESULTS: The results showed a significantly higher DMFS index for CP children with permanent dentition of both sexes when compared to normal children. A significantly higher plaque index was also observed in the study group. A high tendency to delayed eruption of permanent molars and significantly higher percentages of malocclusion and bruxism were observed in the study group with permanent dentition. Residual food and mouth breathing have been frequently found in CP children. CONCLUSIONS: Earlier preventive measures for CP patients are required because they are a high-risk group for dental caries.

Risk factors for dental caries in children with cerebral palsy.

This study was conducted to examine the oral condition and the salivary and microbiological parameters associated with dental caries in 62 children with cerebral palsy, who came from households of low socioeconomic status (Study Group). This group had mixed (6 to 11 years old) and permanent (11 to 16 years old) dentition. Dental examinations were performed to measure dental caries, plaque index, salivary levels of mutans streptococci and lactobacilli, salivary flow rate, pH of stimulated saliva, and buffer capacity of saliva. A group of 67 non-handicapped children from similar socioeconomic backgrounds also were examined using these parameters (Control Group). Data were analyzed statistically by non-parametric tests and by correlation. The results showed that children with cerebral palsy who had permanent dentitions had a higher mean decayed, missing and filled surfaces index, as well as a higher plaque index for both sexes. Microbiological examination revealed higher levels of mutans streptococci among Study Group subjects with mixed dentition than in the Control Group. Also, lactobacillus counts were higher in the Study Group, regardless of sex or dentition. With respect to salivary flow rate, pH and buffering capacity, lower mean values were obtained for the Study Group.

Effects of intracanal irradiation with Nd: YAG laser / Efeitos da irradiaçäo intracanal com laser de Nd: YAG

O propósito deste estudo foi avaliar o efeito da irradiçäo do laser de Nd: YAG em canais radiculares de incisivos centrais superiores contaminados (in vitro). A limpeza, desinfecçäo e preparo do canal radicular säo passos importantes para o sucesso do tratamento endodôntico. Contudo, a desinfecçäo do canal radicular pelos métodos tradicionais näo consegue eliminar os microorganismos dos túbulos dentinários e canais laterais. Recentes estudos têm mostrado que a reduçäo da permeabilidade dentinária é um importante fator na diminuiçäo da fixaçäo bacteriana. Outros pesquisadores usam o laser para a desinfecçäo dos canais radiculares e com resultados encorajadores. Neste trabalho foram utilizados 12 dentes incisivos, seccionados, em seu terço médio, esterilizados e inoculado 10 µl de cultura de Streptococcus sanguis (ATCC 105556) no interior do canal radicular. Os grupos foram irradiados com laser de Nd: YAG na potência de 15 Hz, 100 mJ, e 1,5 W por 10, 20, 30 segundos, em movimentos helicoidais do ápice para cervical usando uma fibra de 300 µm de diâmetro. Depois os espécimes foram colocados em soluçäo salina, diluídos e aplicados em meio de cultura (Tryptic Soy Agar - TSA). O número de culturas formadas, foi contado e avaliado. O experimento mostrou uma reduçäo na viabilidade do Streptococcus sanguis nos tempos de 20 e 30 segundos

Fatores de virulência do Actinobacillus actinomycetemcomitans: outros possíveis fatores / Virulence factors of Actinobacillus actinomycetemcomitans: other putative factors

Actinobacillus actinomycetemcomitans está implicado como o agente etiológico da periodontite juvenil localizada. Este organismo possui inúmeros fatores de virulência que podem interferir no reparo tissular. 50 isolados de A. actinomycetemcomitans de pacientes com periodontite foram examinados para avaliar outros possíveis fatores de virulência. Neste estudo, foi avaliada a produçäo de cápsula, DNase, coagulase, fibrinolisina, atividade proteolítica, hemolisina e bacteriocina, assim como hemaglutinaçäo, sensibilidade ao soro, aderência às células epiteliais, hidrofobicidade e virulência de A. actinomycetemcomitans. Todos os isolados foram resistentes para todos os tipos de soro utilizados. 70 por cento a 94 por cento dos isolados foram alfa-hemolíticos e aglutinaram todos os tipos sanguíneos. A maioria dos isolados produziu substâncias antagonistas e apresentaram baixa hidrofobicidade. Nenhum dos isolados foi patogênico para camundongos. Pouco se sabe, sobre a açäo e como esses fatores podem agir no desenvolvimento da doença periodontal, sendo necessários estudos adicionais para uma aplicaçäo em termos de sistemática e de patogênese

Infecçäo: principal causa de insucessos em implantes dentários / Infection: the major determinant of failures in dental implants

Este artigo analisa os microrganismos isolados dos casos de implantes dentários bem-sucedidos e dos malsucedidos, com base nas alteraçöes ecológicas que determinam o aparecimento das peri-implantes. Aborda, por outro lado, os procedimentos básicos a serem adotados no controle das infecçöes em Implantodontia com destaque para a profilaxia antibiótica

Occurrence of plasmids in A. actinomycetemcomitans isolated in different countries / Ocorrência de plasmídios em A. actinomycetemcomitans provenientes de diferentes países

A ocorrência de plasmídios em cepas de A. actinomycetemcomitans apresenta resultados contraditórios. O objetivo do presente estudo foi o de detectar a ocorrência de elementos extracromossômicos em amostras de bactérias provenientes de diferentes países. Foram analisadas 57 cepas isoladas no Brasil, na Suécia, no Quênia e no Japäo, além de amostras de referência. Entre as cepas analisadas, 15 apresentaram plasmídios, através do método de BIRBOIM; DOLY, sendo 14 isoladas no Brasil e uma, na Suécia. As amostras isoladas no Japäo e no Quênia näo apresentaram plasmídios. Esses resultados demonstraram uma possível variabilidade na ocorrência de plasmídios detectáveis entre amostras provenientes de diferentes países