Cuspal Deflection in Premolar Teeth Restored with Bulk-Fill Resin-Based Composite Materials.

The present study investigated the effect of three high-viscosity bulk-fill resin-based composite materials on cuspal deflection in natural teeth. Thirty-two sound maxillary premolar teeth with large slot mesio-occlusal-distal cavities were distributed into four groups (n=8). Three groups were restored with bulk-fill resin composite materials (Tetric EvoCeram Bulk Fill, Ivoclar Vivadent, Schaan, Liechtenstein; x-tra fil, VOCO, Cuxhaven, Germany; and SonicFill, Kerr, Orange, CA, USA) in a single 4-mm increment. The conventional composite group, Filtek Z100 (3M ESPE, St Paul, MN, USA), was used to restore the cavities in 2-mm increments. Cusp deflection was recorded postirradiation using a Nikon measurescope UM-2 (Nikon, Tokyo, Japan) by measuring the changes in the bucco-palatal widths of the teeth at five minutes, 24 hours, and 48 hours after completion of the restorations. Cuspal deflection was significantly higher in the conventional composite than in the Tetric EvoCeram Bulk Fill ( p=0.0031), x-tra fil ( p=0.0029), and SonicFill Bulk ( p=0.0002) groups. There were no significant differences in cuspal deflection among the three bulk-fill materials (all p<0.05). In conclusion, all the investigated bulk-fill resin composites exhibited cuspal deflection values that were smaller than those associated with a conventional incrementally placed resin composite.

Attachment and proliferation of dental pulp stem cells on dentine treated with different regenerative endodontic protocols.

AIM: To investigate the attachment and proliferation of dental pulp stem cells (DPSC) on dentine treated with various endodontic regeneration protocols. METHODOLOGY: Standardized dentine samples were irrigated with sodium hypochlorite (1.5% NaOCl) and ethylenediaminetetraacetic acid (17% EDTA) and randomized into four treatment groups and two control groups. The treatment groups were treated with a clinically used concentration of triple antibiotic paste (TAP), double antibiotic paste (DAP), calcium hydroxide (Ca(OH)2 ) or diluted TAP in a methylcellulose system (DTAP) for 1 week. Each sample in the treatment groups was then irrigated with EDTA. The two control groups were treated with EDTA or received no treatment. Dental pulp stem cells were seeded on each dentine specimen (10 000 cells). Lactate dehydrogenase activity assays were then performed to evaluate the attached DPSC after 1 day of incubation. Water-soluble tetrazolium assays were used to determine DPSC proliferation after three additional days of incubation. Friedman's test followed by least significant difference were used for statistical analyses (α = 0.05). RESULTS: Triple antibiotic paste and DTAP regeneration protocols, as well as EDTA-treated dentine, caused significant increases in DPSC attachment to dentine. Triple antibiotic paste, DAP and Ca(OH)2 regeneration protocols caused significant reductions in DPSC proliferation on dentine. However, the DTAP regeneration protocol did not have any significant negative effects on DPSC proliferation. CONCLUSIONS: The clinically used endodontic regeneration protocols that include the use of TAP, DAP or Ca(OH)2 medicament negatively affected DPSC proliferation on dentine. However, the use of DTAP medicament during regenerative endodontic treatment may not adversely affect the proliferation of DPSC.

Effect of triple antibiotic paste with or without ethylenediaminetetraacetic acid on surface loss and surface roughness of radicular dentine.

This study aimed to compare the effect of two concentrations of triple antibiotic paste (TAP) with or without ethylenediaminetetraacetic acid (EDTA) on surface loss and surface roughness of radicular dentine. Human radicular dentine specimens were randomized into six experimental groups (n = 16 per group). The first and second groups were treated with 1,000 mg/mL or 1 mg/mL of TAP for 4 weeks. The third and fourth groups were treated with 1,000 mg/mL or 1 mg/mL of TAP for 4 weeks followed by 17 % EDTA for 5 min. The fifth group was treated with 17 % EDTA for 5 min and the sixth group received no treatment (control). Dentine surface loss and surface roughness were quantified after various treatments using optical and contact profilometry, respectively. One-way ANOVA followed by Fisher's protected least significant differences was used for statistical analyses. All treatment groups showed significantly higher surface loss compared to the untreated dentine. Dentine treated with 1,000 mg/mL had significant increase in surface loss and surface roughness compared to dentine treated with 1 mg/mL of TAP. The use of EDTA after both concentrations of TAP did not have significant additive effect on surface loss and surface roughness of dentine. The clinically used concentration of TAP (1,000 mg/mL) caused significantly higher surface loss and surface roughness of radicular dentine compared to the use of 1 mg/mL of TAP. Furthermore, the substantial amount of dentine surface loss and surface roughness detected in the current study may be attributed to TAP rather than EDTA.

Bioactive nanofibrous scaffolds for regenerative endodontics.

Here we report the synthesis, materials characterization, antimicrobial capacity, and cytocompatibility of novel antibiotic-containing scaffolds. Metronidazole (MET) or Ciprofloxacin/(CIP) was mixed with a polydioxanone (PDS)polymer solution at 5 and 25 wt% and processed into fibers. PDS fibers served as a control. Scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), tensile testing, and high-performance liquid chromatography (HPLC) were used to assess fiber morphology, chemical structure, mechanical properties, and drug release, respectively. Antimicrobial properties were evaluated against those of Porphyromonas gingivalis/Pg and Enterococcus faecalis/Ef. Cytotoxicity was assessed in human dental pulp stem cells (hDPSCs). Statistics were performed, and significance was set at the 5% level. SEM imaging revealed a submicron fiber diameter. FTIR confirmed antibiotic incorporation. The tensile values of hydrated 25 wt% CIP scaffold were significantly lower than those of all other groups. Analysis of HPLC data confirmed gradual, sustained drug release from the scaffolds over 48 hrs. CIP-containing scaffolds significantly (p < .00001) inhibited biofilm growth of both bacteria. Conversely, MET-containing scaffolds inhibited only Pg growth. Agar diffusion confirmed the antimicrobial properties against specific bacteria for the antibiotic-containing scaffolds. Only the 25 wt% CIP-containing scaffolds were cytotoxic. Collectively, this study suggests that polymer-based antibiotic-containing electrospun scaffolds could function as a biologically safe antimicrobial drug delivery system for regenerative endodontics.

Knowledge and attitude of dental trauma among mothers in Iraq.

AIM: To evaluate the knowledge and attitude of Iraqi mothers regarding dental trauma prevention and management. STUDY DESIGN AND METHODS: Mothers (n = 231) that visited two professional dental centres in Mosul, Iraq, were interviewed and asked to answer a three-part questionnaire containing questions about demographic variables, attitudes and knowledge of dental trauma. STATISTICS: The relationships of the demographic variables with the total knowledge score of the correct responses were analysed using two-sample t tests. The number of correct responses regarding management of avulsed teeth compared to that of fractured teeth was evaluated using a paired t test. A 5 % level of statistical significance was applied for the analyses. RESULTS: The mean knowledge score was 5.2 (on a scale of 0-10). No significant differences were found in knowledge score with respect to mothers' age, educational level, working status, personal experience with dental trauma or first aid training (p > 0.05). Mothers with either at least a high school education or previous experience with dental trauma were more likely to recommend that their children wear mouth guards during sports (p = 0.02 and p = 0.03, respectively). Mothers who were 35 years of age and older were more likely to know how to correctly carry an avulsed tooth to a dentist. Mothers' knowledge regarding management of fractured teeth was significantly higher than that of avulsed teeth (p < 0.0001). CONCLUSIONS: Mothers in Mosul, Iraq, did not have sufficient knowledge about the prevention and management of traumatic dental injuries. Intervention programmes should be considered to increase mothers' awareness regarding dental injuries.

The effect of medicaments used in endodontic regeneration on root fracture and microhardness of radicular dentine.

AIM: To investigate the effect of medicaments used in endodontic regeneration on root fracture resistance and microhardness of radicular dentine. METHODOLOGY: The root canals of mandibular premolars (n = 180) were instrumented and randomized into three treatment groups and an untreated control group. Each treatment group received either triple antibiotic paste (TAP), double antibiotic paste (DAP) or calcium hydroxide paste [Ca(OH)2] intracanal medicament. Teeth were kept in saline for 1 week, 1 month or 3 months. After each time-point, 15 teeth were randomly selected from each group and two root cylinders were obtained from each tooth. One cylinder was subjected to a fracture resistance test, and the other cylinder was used for a microhardness test. Two-way ANOVA and Tukey's pairwise comparisons were used for statistical analysis. RESULTS: For the microhardness test, the two-way interaction between group and time was significant (P < 0.001). The intracanal application of TAP and DAP caused significant and continuous decrease in root dentine microhardness after one (P < 0.05) and 3 months (P < 0.001), respectively. The three-month intracanal application of Ca(OH)2 significantly increased the microhardness of root dentine (P < 0.05). The time factor had a significant effect on fracture resistance (P < 0.001). The three intracanal medicaments caused significant decreases in fracture resistance ranging between 19% and 30% after 3-month application compared to 1-week application. CONCLUSION: In this laboratory study, the 3-month application of triple antibiotic paste, double antibiotic paste or calcium hydroxide paste medicaments significantly reduced the root fracture resistance of extracted teeth compared to a 1-week application.

The effect of nonsetting calcium hydroxide on root fracture and mechanical properties of radicular dentine: a systematic review.

The aim of this review was to identify and analyse all studies related to the effect of nonsetting calcium hydroxide [Ca(OH)(2)] on root fracture and various mechanical properties of radicular dentine. A PubMed search was conducted using the keywords 'calcium hydroxide' and 'dentistry' combined with MeSH terms 'tooth fractures' or 'mechanical phenomena' or 'compressive strength'. The search was expanded by including Embase and Web of Science databases, using the keywords 'calcium hydroxide' and 'root' and 'fracture'. The search was supplemented by checking the reference lists from each selected article. Each study had to meet the following criteria to be selected for review: (i) Inclusion of at least one experimental group with root or radicular dentine either filled with or exposed to nonsetting Ca(OH)(2); (ii) inclusion of at least one appropriate control group; and (iii) a minimum of five samples per experimental group. Only articles written in English were included. Of the 16 studies selected initially, 12 in vitro studies fulfilled the selection criteria for inclusion in the final review. No clinical studies that directly supported the correlation between Ca(OH)(2) intracanal dressing and root fracture were found in the literature. However, the majority of in vitro studies showed reduction in the mechanical properties of radicular dentine after exposure to Ca(OH)(2) for 5 weeks or longer. Conversely, the data were inconclusive regarding whether Ca(OH)(2) exposure for 1 month or less had a negative effect on the mechanical properties of radicular dentine.