Thursday, January 18, 2018

Oral bacterial colonization on dental implants restored with titanium or zirconia abutments: 6-month follow-up


Original Article

Abstract

Objective

This investigation aimed to characterize in a 6-month follow-up the microbial profile of implants restored with either titanium or zirconia abutments at the genus or higher taxonomic levels.

Methods

Twenty healthy individuals indicative for implant-retained single restorations were investigated. Half of participants were restored with titanium and half with zirconia abutments. Biofilm was collected from the implant-related sites after 1, 3, and 6 months of loading. The 16S rDNA genes were amplified and sequenced with Roche/454 platform.

Results

A total of 596 species were identified in 360 samples and grouped in 18 phyla and 104 genera. Titanium- or zirconia-related sites as well as teeth showed similar total numbers of operational taxonomic units (OTUs) colonizing surfaces over time. Firmicutes, Proteobacteria, Fusobacteria, Bacteroidetes, and Actinobacteria were the most prevalent phyla with significant differences between different surfaces and time point. Unclassified genera were found in lower levels (1.71% up to 9.57%) on titanium and zirconia samples when compared with teeth, with no significant differences.

Conclusion

Titanium- and zirconia-related surfaces are promptly colonized by a bacterial community similar to those found in the remaining adjacent teeth. Results suggest a selective adhesion of different bacterial genotypes for either titanium or zirconia surfaces. Data also indicate a significant interaction between the relative effects taxa, time point, and sampling site.

Clinical relevance

The present study disclosed a wider spectrum of microorganisms colonizing either titanium- or zirconia-related microbiomes in very early stage of implant colonization, revealing differences and suggesting a probably specific mechanism for selective bacterial adhesion.

Wednesday, January 17, 2018

Sports drink consumption and dental erosion among amateur runners.

J Oral Sci. 2017;59(4):639-643. doi: 10.2334/josnusd.16-0611.

Abstract

 This cross-sectional study assessed the prevalence and potential risk factors for dental erosion in amateur athletes at running events. After a sample calculation, 108 runners from the state of Rio de Janeiro, Brazil, were selected and examined for dental wear by a single trained and calibrated evaluator (kappa = 1.00). To identify risk factors, the runners were interviewed by using a standardized, semi-structured questionnaire. The average (SD) age of the runners was 34.2 (11.45), and the prevalence of dental erosion was 19.4%. Gastroesophageal reflux, running frequency per week, and time expended during competition were associated with dental erosion (P < 0.05). The association between use of isotonic drinks and dental erosion was not significant (P > 0.05). In conclusion, dental erosion was not associated with use of isotonic drinks. However, frequency of exercise per week and gastroesophageal reflux were risk factors for dental erosion.

Tuesday, January 16, 2018

Outcomes of Direct Pulp Capping by Using Either ProRoot Mineral Trioxide Aggregate or Biodentine in Permanent Teeth with Carious Pulp Exposure in 6- to 18-Year-Old Patients: A Randomized Controlled Trial

Journal of Endodontics

 

Abstract


Introduction

This study aimed to compare the success rates of direct pulp capping (DPC) by using either ProRoot Mineral Trioxide Aggregate (MTA) or Biodentine in the cariously exposed permanent teeth of 6- to 18-year-old patients. Gray discoloration was also evaluated.

Methods

Fifty-nine cariously exposed permanent teeth, including teeth with diagnosis of normal pulp, reversible pulpitis, or irreversible pulpitis, early periapical involvement, and exposure size of up to 2.5 mm, were included. Each patient with only 1 cariously exposed tooth was randomly allocated to DPC with either ProRoot MTA (n = 30) or Biodentine (n = 29). Patients were recalled every 6 months. Clinical and radiographic examinations were used to determine success.

Results

Fifty-five patients (mean age, 10 ± 2 years), 27 treated with ProRoot MTA and 28 with Biodentine, were included in the analysis. At mean follow-up of 18.9 ± 12.9 months, the success rate was 92.6% with ProRoot MTA and 96.4% with Biodentine (P > .05; difference, 4%; 95% confidence interval [CI], –8% to 16%). Biodentine was non-inferior to ProRoot MTA. Failures were distributed equally in all categories of pulpal diagnosis and occurred in teeth with no periapical involvement and small exposures (0.5 mm). The survival probabilities of DPC with ProRoot MTA and Biodentine were 0.92 (95% CI, 0.73–0.98) and 0.96 (95% CI, 0.80–0.99). No significant difference was observed between them (P > .05). Gray discoloration was observed only with ProRoot MTA (55%).

Conclusions

Biodentine was non-inferior to ProRoot MTA when used as a DPC material for cariously exposed permanent teeth of 6- to 18-year-old patients. However, Biodentine did not cause any gray discoloration in this study.

Monday, January 15, 2018

Reactions of human dental pulp cells to capping agents in the presence or absence of bacterial exposure.

J Oral Sci. 2017;59(4):621-627. doi: 10.2334/josnusd.16-0625.

Abstract

An ideal pulp-capping agent needs to have good biocompatibility and promote reparative dentinogenesis. Although the effects of capping agents on healthy pulp are known, limited data regarding their effects on bacterial contaminated pulp are available. This study aimed to evaluate the reaction of contaminated pulps to various capping agents to assist clinicians in making informed decisions. Human dental pulp (HDP) cell cultures were developed from extracted human molars. The cells were exposed to a bacterial cocktail comprising Porphyromonas gingivalis, Prevotella intermedia, and Streptococcus gordonii before being cocultured with capping agents such as mineral trioxide aggregate (MTA) Portland cement (PC), and Dycal. HDP cell proliferation was assayed by MTS colorimetric cell proliferation assay, and its differentiation was evaluated by real-time PCR for detecting alkaline phosphatase, dentin sialophosphoprotein, and osteocalcin expressions. MTA and PC had no apparent effect, whereas Dycal inhibited HDP cell proliferation. PC stimulated HDP cell differentiation, particularly when they were exposed to bacteria. MTA and Dycal inhibited differentiation, regardless of bacterial infection. In conclusion, PC was the most favorable agent, followed by MTA, and Dycal was the least favorable agent for supporting the functions of bacterial compromised pulp cells.

Friday, January 12, 2018

Bond strength of universal adhesives to air-abraded zirconia ceramics.

J Oral Sci. 2017;59(4):565-570. doi: 10.2334/josnusd.16-0666.

Abstract

The bond strength of universal adhesives to air-abraded zirconia ceramic was evaluated. Overall, 40 zirconia ceramic blocks with dimensions of 6 × 6 × 4 mm were cut from pre-sintered blanks. The sintered blocks were embedded in self-cured acrylic resin. The zirconia blocks were then randomly allocated to four groups (n = 10) in which different universal adhesives were used, except for the control group in which no universal adhesive was used. A silicon mold was used to build the resin cement. All specimens were stored in distilled water for 24 h at 37°C and mounted on a universal testing machine. They were then subjected to shear bond strength testing at a cross-speed of 0.5 mm/min until failure occurred. The failure modes were analyzed using a digital microscope at 50× magnification. Univariate one-way analysis of variance and Tukey's post-hoc test were used for statistical analysis. Compared with the control group, the groups with universal adhesives showed statistically significant differences (P < 0.05). In addition, there was no statistically significant difference in the bond strengths of the groups with universal adhesives (P > 0.05) . After 24 h of storage, the cementation bond to air-abraded zirconia ceramic was improved by the application of a universal adhesive.

Thursday, January 11, 2018

Cellerant Best of Class 2018

We are fast approaching the selection of the 2018 Cellerant Best of Class Award winners at the Chicago Midwinter Meeting at the end of February. Does your company have a product that is worthy of consideration? If so please feel free to reach out to me and we can see if it may meet the criteria necessary to win Best of Class or recognition as an emerging product.

The 2017 Winners are listed on the Cellerant Web Site.

Good Luck to all and see you all in Chicago!!!

Wednesday, January 10, 2018

New Dental Material Can Resist Biofilm Growth And Kills Bacteria

Researchers at the University of Pennsylvania have developed an antibacterial resin for dental procedures such as cavity fillings. They hope that the material can provide improved fillings that resist tooth decay and last longer.
Conventional materials for dental fillings are prone to being covered in plaque, a sticky biofilm that can lead to tooth decay and filling failure. Researchers at the University of Pennsylvania are working on developing something better. “Dental biomaterials such as these,” said Geelsu Hwang, a researcher involved in the study, “need to achieve two goals: first, they should kill pathogenic microbes effectively, and, second, they need to withstand severe mechanical stress, as happens when we bite and chew.”
Hwang and his colleagues have developed a new dental resin that contains the antimicrobial agent imidazolium. In a key development, the researchers chemically linked the antibacterial agent to the resin, so that it would not leach out into the oral cavity, but would only kill bacteria that come in contact with the resin. “This can reduce the likelihood of antimicrobial resistance,” said Hwang. This approach also means that the resin is unlikely to produce any toxicity in the mouth, but can still be effective at killing microbes on its surface.
The researchers tested the material’s ability to kill microbes and prevent the growth of biofilms, while also ensuring that it had the required mechanical strength to provide a durable filling. The material effectively killed bacteria that contacted it and permitted only small amounts of biofilm to grow on its surface.
When the team tested how much shear force was required to remove the biofilm from the material, they found that only a very small force was required to completely remove the sticky biofilm layer, whereas a force four times as strong could still not remove the biofilm from a control composite resin. “The force equivalent to taking a drink of water could easily remove the biofilm from this material,” said Hwang.
Study in Applied Materials & Interfaces: Nonleachable Imidazolium-Incorporated Composite for Disruption of Bacterial Clustering, Exopolysaccharide-Matrix Assembly, and Enhanced Biofilm Removal…