Antibacterial effect of genetically-engineered bacteriophage ϕEf11/ϕFL1C(Δ36)PnisA on dentin infected with antibiotic-resistant Enterococcus faecalis.

OBJECTIVE: Enterococcus faecalis is a gram-positive facultative anaerobic bacterium, which is present in 30-89% of teeth with postendodontic treatment failures. E. faecalis is capable of penetrating dentinal tubules and surviving as a monoculture after conventional endodontic therapy, indicating that it is resistant to commonly used endodontic disinfection protocols. Different E. faecalis strains have shown resistance to several antibiotics, and have been associated with both dental pathology and systemic infections. The aim of this study was to evaluate the efficacy of a genetically engineered bacteriophage to disinfect dentin infected with antibiotic resistant strains of E. faecalis. METHODS: Extracted human dentin root segments were cemented into sealable two-chamber devices, fabricated from syringe needle caps to form in vitro infected-dentin models. The models were inoculated with an overnight suspension of either E. faecalis V583 (vancomycin resistant strain) or E. faecalis JH2-2 (fusidic acid and rifampin resistant, vancomycin sensitive strain). After 7days of incubation at 37°C, a suspension of a genetically engineered phage, ϕEf11/ϕFL1C(Δ36)PnisA, was added to the root canal of each infected dentin segment, and the incubation was continued for an additional 72-h. Dentin was harvested from the walls of each root canal and assayed for the residual titer of E. faecalis cells. RESULTS: The recovered E. faecalis titer was reduced by 18% for the JH2-2 infected models, and by 99% for the V583 infected models. CONCLUSION: Treatment: of E. faecalis-infected dentin with bacteriophage ϕEf11/ϕFL1C(Δ36)PnisA consistently resulted in a decrease in the residual bacterial population of both vancomycin-sensitive and resistant strains.

Human Histologic Evidence of Reosseointegration Around an Implant Affected with Peri-implantitis Following Decontamination with Sterile Saline and Antiseptics: A Case History Report.

The treatment of peri-implant disease is one of the most controversial topics in implant dentistry. The multifactorial etiology and the myriad proposed techniques for managing the problem make successful decontamination of an implant surface affected by peri-implantitis one of the more unpredictable challenges dental practitioners have to face. This article presents the first known published case report demonstrating human histologic evidence of reosseointegration using a plastic curette for mechanical debridement and dilute sodium hypochlorite, hydrogen peroxide, and sterile saline for chemical detoxification. Guided bone regeneration in the infrabony component of the peri-implantitis lesion was accomplished using calcium sulfate and bovine bone as grafting materials and a porcine collagen barrier for connective tissue and epithelial exclusion.

Histologic and Tomographic Findings of Bone Block Allografts in a 4 Years Follow-up: A Case Series.

The aim of this paper is to report histologic and tomographic findings of fresh frozen bone block allografts bearing dental implants in functional occlusion in a long-term follow-up. Four patients with implants functionally loaded for 4 years on augmented ridges requiring additional mucogingival surgery or implant placement were included in this case series. Cone-beam tomography scans were compared volumetrically between the baseline (first implant placement) and current images. Biopsies of the grafts were retrieved and sent to histological analysis. Volumetric reduction of the grafts varied from 2.1 to 7.7%. Histological evaluation demonstrated well-incorporated grafts with different degrees of remodeling. While data presented in this report are from a small sample size and do not allow definitive conclusions, the biopsies of the grafted sites were very similar to the host's native bone. Remodeling of the cortical portion of the allografts seems to take longer than the cancellous portion. The presence of unincorporated graft remains did not impair the implant success or the health of the surrounding tissues. This is the first time histologic and tomographic long term data of bone allograft have been made available in dentistry.

Histologic and Tomographic Findings of Bone Block Allografts in a 4 Years Follow-up: A Case Series

Abstract The aim of this paper is to report histologic and tomographic findings of fresh frozen bone block allografts bearing dental implants in functional occlusion in a long-term follow-up. Four patients with implants functionally loaded for 4 years on augmented ridges requiring additional mucogingival surgery or implant placement were included in this case series. Cone-beam tomography scans were compared volumetrically between the baseline (first implant placement) and current images. Biopsies of the grafts were retrieved and sent to histological analysis. Volumetric reduction of the grafts varied from 2.1 to 7.7%. Histological evaluation demonstrated well-incorporated grafts with different degrees of remodeling. While data presented in this report are from a small sample size and do not allow definitive conclusions, the biopsies of the grafted sites were very similar to the host's native bone. Remodeling of the cortical portion of the allografts seems to take longer than the cancellous portion. The presence of unincorporated graft remains did not impair the implant success or the health of the surrounding tissues. This is the first time histologic and tomographic long term data of bone allograft have been made available in dentistry.

Resumo O objetivo deste artigo é relatar achados histológicos e tomográficos de aloenxertos ósseos em bloco com implantes dentários em oclusão funcional em um acompanhamento de longo prazo. Quatro pacientes com implantes funcionalmente carregados por 4 anos em rebordos alveolares enxertados, que necessitaram de cirurgia mucogengival ou instalação de implantes adicionais foram incluídos nesta série de casos. Imagens de tomografia cone-beam foram comparados volumetricamente entre o momento inicial (instalação do implante original) e imagens atuais. Biópsias dos enxertos foram coletadas e enviadas para análise histológica. A redução volumétrica dos enxertos variou entre 2,1-7,7%. A avaliação histológica demonstrou enxertos bem incorporados com diferentes graus de remodelação. Embora os dados apresentados neste relato sejam de uma amostra pequena e não permitam conclusões definitivas, as biópsias dos sítios enxertados apresentaram características muito similares ao osso nativo. A remodelação da porção cortical dos aloenxertos parece levar mais tempo do que a porção esponjosa. A presença de remanescentes do enxerto não incorporado não demonstrou impacto no sucesso dos implantes ou na saúde dos tecidos circunjacentes. Este é o primeiro relato com dados histológicos e tomográficos em longo prazo de enxertos ósseos alógenos disponível na odontologia.

Effect of a genetically engineered bacteriophage on Enterococcus faecalis biofilms.

OBJECTIVE: Enterococcus faecalis is a Gram-positive, facultative anaerobic bacterium that is associated with failed endodontic cases and nosocomial infections. E. faecalis can form biofilms, penetrate dentinal tubules and survive in root canals with scarce nutritional supplies. These properties can make E. faecalis resistant to conventional endodontic disinfection therapy. Furthermore, treatment may be complicated by the fact that many E. faecalis strains are resistant to antibiotics. A potential alternative to antibiotic therapy is phage therapy. ϕEf11 is a temperate phage that infects strains of E. faecalis. It was previously sequenced and genetically engineered to modify its properties in order to render it useful as a therapeutic agent in phage therapy. In the current study, we have further genetically modified the phage to create phage ϕEf11/ϕFL1C(Δ36)PnisA. The aim of this study was to evaluate the efficacy of bacteriophage ϕEf11/ϕFL1C(Δ36)PnisA, to disrupt biofilms of two Enterococcus faecalis strains: JH2-2 (vancomycin-sensitive) and V583 (vancomycin-resistant). METHODS: 24h static biofilms of E. faecalis strains JH2-2(pMSP3535 nisR/K) and V583 (pMSP3535nisR/K), formed on cover slips, were inoculated with bacteriophage ϕEf11/ϕFL1C(Δ36)PnisA. After 24 and 48h incubation, the bacterial biomass was imaged by confocal microscopy and viable cells were quantified by colony forming unit measurement. RESULTS: The results showed a 10-100-fold decrease in viable cells (CFU/biofilm) after phage treatment, which was consistent with comparisons of treated and untreated biofilm images visualized as max projections of the Z-series. CONCLUSION: The biomass of both vancomycin-sensitive and vancomycin-resistant E. faecalis biofilms is markedly reduced following infection by bacteriophage ϕEf11/ϕFL1C(Δ36)PnisA.

Bending Resistance and Cyclic Fatigue Life of a new Single-File Reciprocating Instrument Waveone Gold.

OBJECTIVE: The present study aimed to evaluate the bending resistance and cyclic fatigue fracture resistance of a new single-file reciprocating instrument called WaveOne Gold. Reciproc and WaveOne instruments were used as references for comparison. METHODS: Sixty 25-mm NiTi instruments (Reciproc R25, WaveOne Primary and WaveOne Gold Primary) were tested. Flexibility was determined by applying 45° bending tests using a universal testing machine (n=10). A custom-made device was used during cyclic fatigue test (n=10), comprising a stainless steel artificial canal measuring 1.4 mm in diameter, 19 mm in total length with an 86° angle and 6 mm radius of curvature. Possible deformations at the helical shaft and mode of fracture were evaluated using scanning electron microscopy analysis. Statistical analysis was performed using one-way analysis of variance. Post hoc pair-wise comparisons were performed using Tukey's test for multiple comparisons (P<0.05). RESULTS: WaveOne presented significantly higher bending resistance than the other tested systems (P<0.05), whereas Reciproc presented the lowest bending resistance (P<0.05). Reciproc revealed a significantly longer cyclic fatigue fracture resistance than the other systems (P<0.05). CONCLUSION: Although WaveOne Gold presented higher flexibility than WaveOne, no differences in the resistance to fatigue were observed between both systems. The Reciproc files were more flexible and resistant to fatigue for the angle of curvature of 86° and 6 mm radius than WaveOne and WaveOne Gold files.