Oral Streptococci Biofilm Formation on Different Implant Surface Topographies.

The establishment of the subgingival microbiota is dependent on successive colonization of the implant surface by bacterial species. Different implant surface topographies could influence the bacterial adsorption and therefore jeopardize the implant survival. This study evaluated the biofilm formation capacity of five oral streptococci species on two titanium surface topographies. In vitro biofilm formation was induced on 30 titanium discs divided in two groups: sandblasted acid-etched (SAE- n = 15) and as-machined (M- n = 15) surface. The specimens were immersed in sterilized whole human unstimulated saliva and then in fresh bacterial culture with five oral streptococci species: Streptococcus sanguinis, Streptococcus salivarius, Streptococcus mutans, Streptococcus sobrinus, and Streptococcus cricetus. The specimens were fixed and stained and the adsorbed dye was measured. Surface characterization was performed by atomic force and scanning electron microscopy. Surface and microbiologic data were analyzed by Student's t-test and two-way ANOVA, respectively (P < 0.05). S. cricetus, S. mutans, and S. sobrinus exhibited higher biofilm formation and no differences were observed between surfaces analyzed within each species (P > 0.05). S. sanguinis exhibited similar behavior to form biofilm on both implant surface topographies, while S. salivarius showed the lowest ability to form biofilm. It was concluded that biofilm formation on titanium surfaces depends on surface topography and species involved.

Effects of different concentrations of carbamide peroxide and bleaching periods on the roughness of dental ceramics.

The wide use of dental bleaching treatment has brought concern about the possible effects of hydrogen peroxide on dental tissue and restorative materials. The objective of this study was to evaluate in vitro the effect of nightguard bleaching on the surface roughness of dental ceramics after different periods of bleaching treatment. Fifteen specimens of 5 × 3 × 1 mm were created with three dental ceramics following the manufacturers' instructions: IPS Classic (Ivoclar-Vivadent); IPS d.Sign (Ivoclar-Vivadent); and VMK-95 (Vita). A profilometer was used to evaluate baseline surface roughness (Ra values) of all ceramics by five parallel measurements with five 0.25 mm cut off (Λc) at 0.1 mm/s. Afterwards, all specimens were submitted to 6-h daily bleaching treatments with 10% or 16% carbamide peroxide (Whiteness- FGM) for 21 days, while control groups from each ceramic system were stored in artificial saliva. The surface roughness of all groups was evaluated after 18 h, 42 h, 84 h, and 126 h of bleaching treatment. The surface roughness of each specimen (n = 5) was based on the mean value of five parallel measurements in each time and all data were submitted to two-way repeated measures ANOVA and Tukey's post-hoc test (α = 0.05). No significant differences in ceramic surface roughness were observed between untreated and bleached ceramic surfaces, regardless of bleaching intervals or bleaching treatments. This study provided evidence that at-home bleaching systems do not cause detrimental effects on surface roughness of dental ceramics.

Effects of different concentrations of carbamide peroxide and bleaching periods on the roughness of dental ceramics

The wide use of dental bleaching treatment has brought concern about the possible effects of hydrogen peroxide on dental tissue and restorative materials. The objective of this study was to evaluate in vitro the effect of nightguard bleaching on the surface roughness of dental ceramics after different periods of bleaching treatment. Fifteen specimens of 5 × 3 × 1 mm were created with three dental ceramics following the manufacturers' instructions: IPS Classic (Ivoclar-Vivadent); IPS d.Sign (Ivoclar-Vivadent); and VMK-95 (Vita). A profilometer was used to evaluate baseline surface roughness (Ra values) of all ceramics by five parallel measurements with five 0.25 mm cut off (Λc) at 0.1 mm/s. Afterwards, all specimens were submitted to 6-h daily bleaching treatments with 10 percent or 16 percent carbamide peroxide (Whiteness- FGM) for 21 days, while control groups from each ceramic system were stored in artificial saliva. The surface roughness of all groups was evaluated after 18 h, 42 h, 84 h, and 126 h of bleaching treatment. The surface roughness of each specimen (n = 5) was based on the mean value of five parallel measurements in each time and all data were submitted to two-way repeated measures ANOVA and Tukey's post-hoc test (α = 0.05). No significant differences in ceramic surface roughness were observed between untreated and bleached ceramic surfaces, regardless of bleaching intervals or bleaching treatments. This study provided evidence that at-home bleaching systems do not cause detrimental effects on surface roughness of dental ceramics.

Influence of titanium surface treatments on formation of the blood clot extension.

The aim of this in vitro study was to evaluate the influence of 3 different implant surface treatments on the extension of human blood clot formation. For this purpose, the 3 types of surfaces (as-machined; test group 1, titanium discs blasted with aluminum oxide particles and washed with nitric acid; test group 2, titanium discs blasted with titanium oxide particles and washed with maleic acid) obtained were evaluated regarding topography and blood clot extension formation. Data suggest that different treatments applied on implant surfaces confer different mechanical and chemical properties, and that titanium discs blasted with aluminum oxide particles and washed with nitric acid exhibited the widest blood clot extension (P < .001).

Antibacterial activity of various self-etching adhesive systems against oral streptococci.

The antibacterial properties of self-etching adhesive systems constitute an important issue in operative dentistry, since viable bacteria can still be present after cavity preparation. The current study evaluated the antibacterial activity of five one-step self-etching adhesives (SEAs) and four self-etching primers (SEPs) against oral streptococci. Clearfil S3 (S3), One-Up Bond F Plus (OU), Futurabond NR (FB), GBond (GB), Xeno IV (X4), Clearfil SE Bond (SE), Clearfil Protect Bond (PB), Adper SE Plus (AS) and AdheSE (AD) were tested for antibacterial activity against five streptococci species: S oralis, S sanguinis, S cricetus, S mutans and S sobrinus. Chlorhexidine (0.12%) and phosphoric acid (37%) gel were used as control. The agar diffusion test method was used. Plates containing BHI agar and 300 uL of bacterial cell suspension (0.5 MacFarland) were prepared. Holes 6 mm in diameter were made and partially filled with bacteriological agar. Then, 10 uL of each SEA or SEP was dropped and the plates were incubated under microaerophilic atmosphere at 37 degrees C for 48 hours and the diameter of each halo was registered. The results were analyzed by two-way ANOVA and Tukey test. PB exhibited the most effective antibacterial activity against oral streptococci. The performances of SE and FB were similar or better than chlorhexidine for all bacteria. S3, X4, AS, AD, OU and GB showed significantly lower inhibition values. Among the species tested, S oralis was the most sensitive to all self-etching adhesive systems; on the other hand, S cricetus, S mutans and S sobrinus were more resistant. Among the self-etching adhesive systems evaluated, Clearfil Protect Bond exhibited the most effective antibacterial activity against oral streptococci.

Collagenase production and hemolytic activity related to 16S rRNA variability among Parvimonas micra oral isolates.

Parvimonas micra are gram positive anaerobic cocci isolated from the oral cavity and frequently related to polymicrobial infections in humans. Despite reports about phenotypic differences, the genotypic variation of P. micra and its role in virulence are still not elucidated. The aim of this study was to determine the genotypic diversity of P. micra isolates obtained from the subgingival biofilm of subjects with different periodontal conditions and to correlate these findings with phenotypic traits. Three reference strains and 35 isolates of P. micra were genotyped by 16S rRNA PCR-RFLP and phenotypic traits such as collagenase production, elastolytic and hemolytic activities were evaluated. 16S rRNA PCR-RFLP showed that P. micra could be grouped into two main clusters: C1 and C2; cluster C1 harbored three genotypes (HG1259-like, HG1467-like and ICBMO583-like) while cluster C2 harbored two genotypes (ATCC33270-like and ICBMO36). A wide variability in collagenolytic activity intensities was observed among all isolates, while elastolytic activity was detected in only two isolates. There was an association between hemolytic activity in rabbit erythrocytes and cluster C2. There was an association between hemolytic activity in rabbit erythrocytes and cluster C1. Although these data suggest a possible association between P. micra genetic diversity and their pathogenic potential, further investigations are needed to confirm this hypothesis.

Bacterial adhesion on smooth and rough titanium surfaces after treatment with different instruments.

BACKGROUND: Newly formed biofilm after implant debridement may challenge the long-term stability of peri-implant therapy. This in vitro study aimed to assess the roughness and adherence of Streptococcus sanguinis after treatment of smooth and rough titanium surfaces with an erbium-doped:yttrium, aluminum, and garnet (Er:YAG) laser, metal and plastic curets, and an air-powder abrasive system. METHODS: Forty titanium disks with smooth-machined surfaces and 40 with sand-blasted and acid-etched surfaces were divided into the following treatment groups: Er:YAG laser; plastic curet; metal curet, and air-powder abrasive system. The surface roughness (roughness average [Ra]) before and after treatments was determined using a profilometer. S. sanguinis (American Type Culture Collection 10556) was grown on treated and untreated specimens, and the amounts of retained bacteria on the surfaces were measured by the culture method. Rough and smooth surfaces with and without a suspension of S. sanguinis were also analyzed using scanning electron microscopy (SEM). RESULTS: For smooth surfaces, the roughest surfaces were produced by metal curets (repeated-measures analysis of variance [ANOVA] and Tukey test; P <0.05). The rough-surface profile was not altered by any of the treatments (repeated-measures ANOVA; P >0.05). Rough surfaces treated with metal curets and air-powder abrasion showed the lowest level of bacterial adhesion (two-way ANOVA and Tukey test; P <0.05). SEM analysis revealed distinct surface profiles produced by all devices. CONCLUSIONS: Metal curets are not recommended for smooth titanium surface debridement due to severe texture alteration. Rough surfaces treated with a metal curet and the air-powder abrasive system were less susceptible to bacterial adhesion, probably due to texture modification and the presence of abrasive deposits.

In vitro adhesion of Streptococcus sanguinis to dentine root surface after treatment with Er:YAG laser, ultrasonic system, or manual curette.

OBJECTIVE: The purpose of this in vitro study was to evaluate the dentine root surface roughness and the adherence of Streptococcus sanguinis (ATCC 10556) after treatment with an ultrasonic system, Er:YAG laser, or manual curette. BACKGROUND DATA: Bacterial adhesion and formation of dental biofilm after scaling and root planing may be a challenge to the long-term stability of periodontal therapy. MATERIALS AND METHODS: Forty flattened bovine roots were randomly assigned to one of the following groups: ultrasonic system (n = 10); Er:YAG laser (n = 10); manual curette (n = 10); or control untreated roots (n = 10). The mean surface roughness (Ra, microm) of the specimens before and after exposure to each treatment was determined using a surface profilometer. In addition, S. sanguinis was grown on the treated and untreated specimens and the amounts of retained bacteria on the surfaces were measured by culture method. RESULTS: All treatments increased the Ra; however, the roughest surface was produced by the curettes. In addition, the specimens treated with curettes showed the highest S. sanguinis adhesion. There was a significant positive correlation between roughness values and bacterial cells counts. CONCLUSION: S. sanguinis adhesion was the highest on the curette-treated dentine root surfaces, which also presented the greatest surface roughness.

Implant surface analysis and microbiologic evaluation of failed implants retrieved from smokers.

The aim of this study was to evaluate the microbiota and surface of failed titanium dental implants from 4 manufacturers. Twelve mobile dental implants were retrieved from 10 smokers after 3 to 10 years of functional loading. Before implant removal, microbial samples were taken and evaluated using polymerase chain reaction. After implant removal, analyses of the failed implant surfaces were performed using scanning electron microscopy and energy-dispersive spectrometer x-ray. Periodontal pathogens such as Aggregactibacter actinomycetemcomitans, Campylobacter rectus, Eikenella corrodens, Fusobacterium nucleatum, Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythia, and Treponema denticola were detected in all implants in different proportions. Surface analysis showed varying degrees of surface roughness between the samples and the presence of proteinaceous material, appearing mainly as dark stains. Foreign carbon, oxygen, sodium, calcium, aluminum, and silicon elements were also found. Although no material-related causes of implant failure were detected, several periodontal pathogens were identified independently of the surface topography or manufacturer.

Complexo vermelho em indivíduos brasileiros periodontalmente doentes e saudáveis / Red complex in subjects with chronic periodontits and periodontal health

O objetivo deste estudo transversal foi avaliar a presença do complexo vermelho em indivíduos com periodontite crônica e indivíduos periodontalmente saudáveis. Foram selecionados 30 indivíduos, sendo 15 periodalmente saudáveis e 15 com periodontite crónica. Os parâmetros clínicos de profundidade de sondagem (PS), nível clínico de inserção (NCI), presença ou ausência de sangramento à sondagem, placa supragengival visível e supuração, foram avaliados em seis sítios por dente.Amostras de placa subgengival foram coletadas de nove sítios mésio-vestibulares, no grupo saudável, e de seis sítios com PS e NIC ≥5 mm e três sítios com PS e NIC ≤4 mm no grupo com periodontite crónica. As amostras foram avaliadas pelo teste Checkerboarad DNA-DNA Hybridizatíonpaïa a presença de Tannerela forsythia, Treponema dentícola e Porphyromonas gingivalis. Diferenças microbiológicas entre os dois grupos foram avaliadas por meio do teste U de MannWhitney. O grupo de indivíduos periodontalmente saudáveis apresentou níveis médios de contagem (x105±DP) de T. forsythia, T.denticola, fg/ng/Vã/fs