mahsa sobhi afshar

Conventional drug mixtures used in regenerative endodontic procedures have a toxic effect and no consensus has been reached about their best composition and concentration. Therefore, the aim of this study was to determine minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and minimum biofilm inhibitory concentration (MBIC) of the antimicrobial preparations and to compare their antimicrobial efficacy on bovine dentin infected by Enterococcus faecalis.

For this original ex vivo investigation, prepared concentrations (MIC, MBC, and MBIC) of triple antibiotic paste (TAP), double antibiotic paste (DAP), modified triple antibiotic paste (MTAP)‑1, MTAP2, co‑amoxiclav, and calcium hydroxide (CH) were added to the prepared bovine dentin blocks (which incubated in E.faecalis suspension previously) and incubated for 3 days. The samples were subsequently prepared for culture and CFU counts. Statistical analysis of data was carried out using one‑way analysis of variance and post hoc tests. The statistical power was set at P < 0.05.

All medicament groups significantly showed an antimicrobial efficacy compared with negative control (without antibiotic) (P < 0.001). TAP, DAP, co‑amoxiclav, and CH (at its MBC value) were significantly capable of eliminating E. faecalis biofilm and showed no significant difference in comparison with positive control (complete biofilm removal) (P < 0.05).

TAP, DAP, co‑amoxiclav, and CH (at its MBC value) could effectively eliminate biofilm bacteria on the dentin surface. Antimicrobial efficacy of other medicaments containing cefaclor or clindamycin was limited.

Conventional drug mixtures used in regenerative endodontic procedures have a toxic effect and no consensus has been reached about their best composition and concentration. Therefore, the aim of this study was to determine minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and minimum biofilm inhibitory concentration (MBIC) of the antimicrobial preparations and to compare their antimicrobial efficacy on bovine dentin infected by Enterococcus faecalis.

For this original ex vivo investigation, prepared concentrations (MIC, MBC, and MBIC) of triple antibiotic paste (TAP), double antibiotic paste (DAP), modified triple antibiotic paste (MTAP)‑1, MTAP2, co‑amoxiclav, and calcium hydroxide (CH) were added to the prepared bovine dentin blocks (which incubated in E.faecalis suspension previously) and incubated for 3 days. The samples were subsequently prepared for culture and CFU counts. Statistical analysis of data was carried out using one‑way analysis of variance and post hoc tests. The statistical power was set at P < 0.05.

All medicament groups significantly showed an antimicrobial efficacy compared with negative control (without antibiotic) (P < 0.001). TAP, DAP, co‑amoxiclav, and CH (at its MBC value) were significantly capable of eliminating E. faecalis biofilm and showed no significant difference in comparison with positive control (complete biofilm removal) (P < 0.05).

TAP, DAP, co‑amoxiclav, and CH (at its MBC value) could effectively eliminate biofilm bacteria on the dentin surface. Antimicrobial efficacy of other medicaments containing cefaclor or clindamycin was limited.

The aim of this study was to determine the effect of MTAD on the expression of virulence factors of Enterococcus faecalis (E.faecalis) considering the role of Gutta-percha/AH26 or Resilon/RealSeal SE as root canal obturating materials. One-hundred and forty-four single-rooted human teeth were instrumented to a standardized apical size. Root canals were infected by E.faecalis (ATCC 29212). Ninety teeth were irrigated with MTAD and randomly divided into three groups. In two groups, root canals were obturated by either Gutta-percha/AH26 or Resilon/RealSeal SE. Root canals were kept unobturated in the third group. The remaining 54 teeth received no final irrigation. All groups were then subdivided into three timepoint subgroups in which dentin powder was obtained from each sample to determine the expression of specific virulence factors of E.faecalis (efa, esp, gel, fsr) using real-time reverse transcription polymerase chain reaction (RT-PCR). Statistical analysis was performed by one-way analysis of variance (ANOVA) and Tukey’s post-hoc test. The statistical power was set at P-value ≤0.05. MTAD was effective against the expression of most of the tested virulence factors, and Gutta-percha/AH26 increased the antibacterial efficacy of MTAD. MTAD could inhibit the expression of some known virulence factors of E.faecalis at the majority of tested timepoints. This may partly explain some of the mechanisms of antimicrobial efficacy of MTAD against this resistant microorganism which is known as one of the main causes of failure of root canal treatment

The purpose of this in-vitro study was to determine and compare the shortest period needed for a triple antibiotic paste (TAP) and calcium hydroxide (Ca(OH)2) plus 2% chlorhexidine (CHX) to eradicate the biofilm of Enterococcus faecalis (EF) from the root canal system.
Sixty-five extracted single-rooted human teeth with straight root canals were selected. The crowns were cut from the cementoenamel junction (CEJ), and canal preparations were done by step-back technique. The smear layer was removed by 17% ethylenediaminetetraacetic acid (EDTA) and 5.25% sodium hypochlorite (NaOCl). Afterwards, the samples were sterilized with gamma ray and were placed inside microtubes for one week. During this week, the teeth were infected with EF. Then, a TAP and Ca(OH)2 mixed with 2% CHX were inserted into the canals. The roots were cut longitudinally, and dentin chips were collected from the apical part of the roots by a round bur to the depth of 400 μm. The vital bacterial load was assessed by counting the numbers of colony-forming units (CFUs).
The paste of Ca(OH)2 mixed with 2% CHX was able to eradicate the EF biofilm in three days. The TAP was able to eradicate the biofilm of EF in seven days.
It seems that Ca(OH)2 mixed with 2% CHX is more potent than the TAP against EF biofilm.

Since the emergence of normal occlusion concept, selecting an appropriate treatment plan with or without tooth extraction has been a controversial subject. Nowadays, both methods can be successfully used for treatment of patients. However, some clinicians still believe that non-extraction orthodontic treatments have fewer complications. The purpose of this study was to evaluate dental arch dimensional changes following non-extraction orthodontic treatment.
A total of 200 pre- and post-treatment diagnostic dental casts belonging to 100 patients (non-ext treated by 0.18 roth system) who met the inclusion criteria for this study were collected from the archives of Shahid Beheshti Dental School. Sampling was nonrandomized. A digital caliper with the accuracy of 0.1 mm was used for the measurement of variables such as inter-canine width , inter-premolar width and inter-molar width.
Non-extraction orthodontic treatment increased all the variables, except for the mandibular inter-canine width and incisor-canine distance.
Non-extraction orthodontic treatment causes a significant increase in almost all dental arch parameters. This increase manifests as teeth flaring.