Journal of Dental Materials and Techniques
Volume:10 Issue: 2, Spring 2021

Fluoride varnishes are used for caries prevention and treatment of dentin hypersensitivity, and its main purpose is to prolong the contact time between fluoride and tooth. The present study aimed to compare the amount of fluoride released and recharge from three conventional varnishes with resin-modified glass ionomer (RMGI). 

This experimental in vitro study was carried on blocks of human teeth extracted for orthodontic reasons. Three commercially available fluoride varnishes (Fluor protector (FP), Duraphat (DP), Clinpro White Varnish (CWV)) a Giomer (PRG-Barrier Coat), and an RMGI (Clinpro XT) were applied in these blocks, divided into five groups (eight samples each one). The readings were carried out using an ion-selective electrode and a potentiometer. After 30 days of study, the recharge capacity of these materials was evaluated immersing the samples in 20,000 parts per million (ppm) sodium fluoride gel.

 Significant differences were found when comparing FP with the rest of the materials analyzed in this study since it released the lowest amount of fluoride with 1.01 ppm. The Giomer released 1.90 ppm, whereas CWV and DP released the highest amount of fluoride with 5.41 ppm and 4.76 ppm, respectively. The RMGI was more constant during the first five days and demonstrated a greater recharge capacity.

 All varnishes demonstrated the greatest fluoride release during the first 24 h, and a marked decrease was observed after this period. The RMGI presented a considerable amount of fluoride and the best capacity for recharge.

The objective of this study was to determine the attitude of dental practitioners towards radiation protection principles and radiographic techniques. We aimed to assess whether dentists’ specialty and university membership impacted the conducts of radiologic practice. A total of 232 dental offices with intraoral radiographic devices in Mashhad, Iran were randomly selected. Demographic characteristics of dentists as well as radiographic equipment and techniques were recorded. Participants were grouped according to specialty and faculty membership. Chi-square tests were used for statistical analysis and comparison of groups by Statistical Package SPSS v.23. 190 dentists (81.9%) were in general dental practice (GDP) and the remaining 42 (18.1%) worked as specialists in different fields. A significant difference was noted regarding the use of digital sensors between general and specialist dentists (16.8% vs. 35.7%, respectively). Paralleling technique using film holders was employed by 28.6% of specialists and 10% of the general dentists (p <0.05). Half of the specialists used routine thyroid shielding; however, only 28.4% of the GDPs followed this practice (p <0.05). Among the specialists, 19 (45.2%) had faculty membership. Use of a rectangular collimation, long cone, and thyroid shield, except variable exposure time were more common in non-faculty members, although not significantly different. Although most dentists did not follow the standard radiological guidelines, it was noticeable that specialist dentists used more appropriate radiographic techniques. Attention should be focused on under- and postgraduate education and employing strict policies for dental radiologic safety measures.

Silicate-based cement alone and Hydroxyapatite as bone filling materials lead to successful results in implant dentistry and regenerative medicine. The purpose of this study was to compare the adhesion capability of periodontal ligament fibroblast cells (PDLFC) to the Nanohydroxyapatite silicate-based cement and silicate-based cement alone in vitro. Primary cell cultures of PDLFCs were obtained from clinically healthy third molars teeth. These third molars were either extracted for orthodontic reasons or extracted due to the impaction of teeth. Cells subcultured at a density of 10000 cells/well in 24-well plates. Methyl-tetrazolium bromide (MTT) assay was performed to evaluate the survival and proliferation of fibroblasts on 24h, 72h, and 1week after the cell culture. Scanning Electron Microscopy (SEM) analysis was used to examine the morphology of PDLFCs on the two scaffolds. Cells were found growing in close proximity to both minerals but in terms of fibroblast cell attachment. Adding Nanohydroxyapatite did not improve cellular proliferation and silicate-based cement alone showed superior cellular proliferation in 72 hours. After 24h and 1week both minerals showed the same response. Although both Nanohydroxyapatite silicate-based cement and silicate-based cement alone are biocompatible, but nanohydroxyapatite silicate-based cement did not show improved biological activities when compared with silicate-based cement.

Determining working length had always been one of the most crucial factors in evaluating prognosis. Radiography as a gold standard way nowadays has some flaws like making a 3D object, image distortion, not measuring the exact location of apical foramen, and putting the patient in a direct X-ray exposure. Here, we compare these three ways in measuring working length of single canal teeth that are narrow. Initially thirty single canal teeth with narrow canals were selected. After preparing the access cavity, the teeth were mounted in alginate for measuring working length with an apex locator. After that, they mounted in chalk in order to determine the working length using conventional and digital radiographs. Finally, the teeth were removed from the mount and the exact working length assessed using a hand file to compare with the three mentioned methods. This study showed that the mean measured working length of root canal therapy had a significant difference between the four methods (P=0.003). Bonferroni post hoc test showed that the mean exact working length of root canal therapy was significantly lower than measured working length of root canal therapy by conventional radiography (P=0.002), digital radiography (P=0.001) and Raypex6 apex locator (P=0.01). However, there was no significant difference between these three methods (P>0.05). The results of this study showed that the mean measured working length of root canal therapy had no significant difference between digital radiography, conventional radiography, and Raypex6 apex locator but these three methods had a significant difference with the exact teeth length

The success of the endodontic treatment is closely associated with eliminating endodontic microbiota especially bacteria like Enterococcus Faecalis (E. Faecalis). Irrigation solutions are suggested for this purpose but there are contraries regarding irrigations and their concentrations. This study aimed to compare antibacterial efficacy of irrigations including 2.5% Sodium hypochlorite (NaOCl), 2% Chlorhexidine (CHX), and 1.5% Hydrogen peroxide (H2O2).  

Fifty deciduous human extracted teeth were divided into 3 groups of 15 teeth, 2.5% NaOCl, 2% CHX, 1.5% H2O2, and 5 teeth in the negative control group. Later, root canals were inoculated by E. Faecalis. After cleaning and shaping, we irrigated the root canals of the teeth in each group with NaOCl, CHX, and H2O2. Samples were obtained again and sent for microbiological evaluation. Wilcoxon signed-rank test, Paired sample T-test, and Kruskal–Wallis were used to analyze data.

All 3 groups showed significant bacterial reduction (p <0.05). NaOCl and CHX showed no significant difference (P=0.415). But the reduction of these 2 groups was higher than H2O2 (p

2.5% NaOCl and 2% Chlorhexidine showed considerable efficacy against E. Faecalis while 1.5% Hydrogen peroxide was not able to eradicate all of E. Faecalis colonies. Hence, NaOCl and CHX solutions can be used for decontamination of infected root canals

Propolis is a resinous substance produced by honeybees. Despite antimicrobial properties, tooth discoloration has been reported during its application as intracanal medicament. The aim of this study was to assess the effect of intracanal propolis removal on crown discoloration. In this experimental study, after access cavity and canal preparation was performed in 40 intact anterior teeth, they were divided into three groups. In group 1 propolis was placed in the canal and pulp chamber while in group 2, it was applied into the canal only. The canals of third group were filled with distilled water as control. After six months, labial surfaces of all teeth were digitally photographed by a digital camera. Propolis was then completely removed and photography was repeated. Tooth color was evaluated in the labial surface using CIE Lab system and Photoshop software. Overall color change (ΔE), change in lightness (ΔL), greenness-redness (Δa) and blueness-yellowness (Δb) were analyzed. ΔL and Δa values were significantly different in all three groups (p <0.001). The difference between groups 1 and 2 was not significant for ΔL or Δa, but groups 1 and 3 were significantly different in ΔL and Δa (p <0.001). Groups 2 and 3 were significantly different in ΔL and Δa (p <0.001). Coronal discoloration after six-month application of propolis as intracanal medicament was not reversed by its removal. Location of application of propolis (in the canal or both canal and pulp chamber) had no significant effect on degree of coronal discoloration.

This study was directed to evaluate the effect of different operating temperatures on the change in working length when using the XP-endo shaper file. A total of 20 plastic blocks with16 mm curved canals were used in this study. The working length was adjusted to be 15 mm using a customized Teflon stopper (10mm in length) which was used with all files in the study. The preparation was done using the XP-endo shaper file (FKG, La Chaux-de-Fonds, Switzerland) according to the manufacturer’s instructions. The blocks were divided into 2 groups: Group 1: body temperature, Group 2: room temperature. Pre and post instrumentation imaging of the blocks was done using the stereomicroscopy at 8x. The images were superimposed to create a composite image on which the evaluation of working length change was done. Mann-Whitney U test was used to compare the change in working length in the two groups. There was no statistically significant difference between the two groups (P ≤ 0.05). Within the parameters of this study, although both groups showed an increase in working length when using the XP-endo shaper file, the operating temperature did not have an effect.

Restoration of freshly erupted permanent first molars with extensive caries is a challenge in pediatric dentistry. This study aimed to compare the fracture resistance of permanent molars with undermined walls restored with amalgam and composite resin along with cusp reduction, reinforcement of the walls with glass ionomer (GI) or no further intervention. This experimental in-vitro study evaluated 72 freshly extracted sound human third molars with almost equal dimensions. After cavity preparation, the teeth were then randomly divided into three groups. In group 1, the undermined area was reinforced with light-cure GI. Group 2 received a 2 mm cuspal cap, and group 3 received no intervention. Half of the teeth in each group were restored with composite resin and the other half with amalgam. The teeth then underwent thermocycling and their fracture resistance was measured by a universal testing machine. Data were analyzed using two-way ANOVA. No significant difference was noted in fracture resistance among three procedures in teeth restored with composite (P=0.589). However, this difference was significant in teeth restored with amalgam (P=0.001). The current results indicated when esthetics is not a priority, applying amalgam restorations with GI-reinforced undermined walls might be suitable for restoration of freshly erupted permanent first molars with extensive caries.