Frontiers in Dentistry
Volume:11 Issue: 1, Jan 2014

The aim of this study was to assess the efficacy of apical negative pressure (ANP), manual dynamic agitation (MDA), passive ultrasonic irrigation (PUI) and needle irrigation (NI) as final irrigation activation techniques for smear layer removal in curved root canals. Mesiobuccal root canals of 80 freshly extracted maxillary first molars with curvatures ranging between 250 and 350 were used. A glide path with #08-15 K files was established before cleaning and shaping with Mtwo rotary instruments (VDW, Munich, Germany) up to size 35/0.04 taper. During instrumentation, 1 ml of 2.5% NaOCl was used at each change of file. Samples were divided into 4 equal groups (n=20) according to the final irrigation activation technique: group 1, apical negative pressure (ANP) (EndoVac); group 2, manual dynamic agitation (MDA); group 3, passive ultrasonic irrigation (PUI); and group 4, needle irrigation (NI). Root canals were split longitudinally and subjected to scanning electron microscopy. The presence of smear layer at coronal, middle and apical levels was evaluated by superimposing 300-µm square grid over the obtained photomicrographs using a four-score scale with X1,000 magnification. Amongst all the groups tested, ANP showed the overall best smear layer removal efficacy (p < 0.05). Removal of smear layer was least effective with the NI technique. ANP (EndoVac system) can be used as the final irrigation activation technique for effective smear layer removal in curved root canals.

The amount and consistency of the applied forces to the tooth are important factors in tooth movements; therefore, the aim of this study was to compare the initial force and the force loss of three brands of elastics in 24 hours. In this in-vitro study sixty non-latex elastics (3/16 medium) from three companies (Forestadent, Dentaurum and Ortho Technology) were randomly selected. Two static tests were performed, the first in a dry environment to evaluate the initial force and the other performed in a wet environment (artificial saliva) to evaluate the force loss in 24 hours. The Universal testing machine measured the forces after stretching the elastics to three times the lumen diameter. Data were analyzed by repeated measures ANOVA, One-way ANOVA, Tukey-HSD, Paired samples test, and one sample test. The difference between the brands was significant (p=0.002). Force loss was observed in all samples; 4-7.5% force loss occurred after one hour and 19-38% force loss occurred after 24 hours. The average initial force of Forestadent and Ortho Technology was significantly higher than marketed forces (p<0.001), but the initial force of Dentaurum elastics was similar to the marketed force. The force loss over 24 hours time period was Forestadent>Dentaurum>Ortho-Technology. According to the initial force and force loss percentage it is suggested to replace the non-latex elastics several times a day.

The aim of this study was to compare the level of agreement between four operators with different levels of experience for two methods of detecting secondary enamel and dentin carious lesions in composite restored teeth. Sixty teeth of 40 patients with with secondary carious lesions in the composite resin were selected. The teeth were examined by two methods; visual inspection and a laser fluorescence device (DIAGNO dent pen 2190) by four operators including an undergraduate student, a dentist with 5 years of clinical experience, a general dentist with 12 years of clinical experience and an oral and maxillofacial radiologist. Cohen''s kappa statistic was applied in order to assess the agreement between the diagnoses performed by the four operators with each diagnostic method. The diagnosis performed by different operators achieved an excellent agreement with high ICC. DIAGNOdent can be a useful device for secondary caries detection in posterior teeth as an adjunct to visual examination.

The prenatal period is the best time for health interventions. The aim of this study was to evaluate the effects of different methods of anticipatory guidance presentation on the change of knowledge and attitude of pregnant women regarding oral healthcare in the mother, infant and toddler. In this quasi-experimental study, 90 pregnant women attended one health center in Zahedan, Iran; they were divided into direct intervention, indirect intervention and control groups. A self-reported questionnaire was completed before intervention. The guidance was presented to the direct intervention group, by PowerPoint and to the indirect group by pamphlet. Immediately after the intervention, the questionnaire was completed by intervention groups and two months later by all participants. Difference in the scores at start and end was calculated. Mann-Whitney, Kruskal-Wallis with Dunn’s post hoc and Friedman with K-W post-hoc tests were used for statistical analysis. The data was analyzed using SPPS version 19 software at a significance level of 0.05. The change in scores of knowledge relevant to maternal, infant and toddler’s oral health and attitude toward maternal oral healthcare had significant differences in the three studied groups (P>0.05), The changes of scores in the four mentioned variables in the intervention groups were significantly higher than controls. In comparison between the intervention groups, the change in score of knowledge about maternal oral healthcare was significantly higher in the direct intervention group (P=0.023). Anticipatory guidance presentation led to change in the score of knowledge about maternal, infant and toddler’s oral health and attitude towards maternal oral health in comparison to no presentation. The direct presentation had superiority over indirect in increasing knowledge about maternal oral healthcare.

To eliminate microorganisms that are responsible for pulpal and periapical infections and to prevent reinfection of the root canal system an effective chemomechanical preparation by irrigants with sustained antimicrobial activity is beneficial. Hereby, we evaluated the residual antibacterial activity of MTAD after canal obturation at different time intervals. A total of 120 human single-canalled anterior teeth were selected. The root canals were instrumented to a standardized apical size. Among all, 90 teeth received final irrigation with MTAD and were divided into three groups according to their obturation materials; i.e. gutta-percha/AH26, Resilon/RealSeal SE and positive controls. All these groups were divided into three 1-, 3- and 6-week time interval subgroups. Thirty teeth as negative control had no final irrigation with MTAD, but were obturated with gutta-percha/AH26 or Resilon/RealSealSE. Dentin powder was prepared after 1, 3 and 6 weeks. Dentin powder was exposed to Enterococcus faecalis for 24h and then cultured. Colony Forming Unit (CFU) was counted. Residual antimicrobial activity of MTAD in the teeth obturated with gutta-percha/AH26 was significantly higher than the teeth obturated with Resilon/RealSeal SE (p<0.001). It also showed a time dependent decrease in MTAD antimicrobial activity for all groups. The highest antimicrobial activity of MTAD was found in the 1-week positive control and 1-week gutta-percha/AH26 specimens. The lowest antimicrobial activity of MTAD was found in 6-week Resilon/RealSeal SE samples and then the negative controls. MTAD had antimicrobial activity even at the sixth week, although it had a time-dependent decrease. Resilon/Epiphany SE significantly decreased antimicrobial activity of MTAD at all time points.

To study the immunohistochemical pattern of CD 117, glial fibrillary acidic protein (GFAP), smooth muscle actin (SMA) and CD 43 in pleomorphic adenoma (PA), adenoid cystic carcinoma (AdCC) and polymorphous low grade adenocarcinoma (PLGA) of minor salivary glands. Twenty cases of PA, 20 cases of AdCC and 10 cases of PLGA were retrieved from record files along with their paraffin blocks at Armed Forces Institute of Pathology, Pakistan. New histological diagnosis was made on freshly prepared H&E sections followed by application and analysis of immunostains. The mean age of the patients was 44 ± 15 (mean SD) (range; 17-86) years. There were 26 male and 24 female patients with a male to female ratio of 1.08:1. Fourteen cases of PA, 14 cases of AdCC and 6 cases of PLGA were positive for CD117. In case of GFAP, only 9 cases of AdCC and 3 cases of PLGA were positive; however, 16 cases of PA were also positive. Twelve cases of AdCC and 7 cases of PA were positive for SMA and half of the PLGA cases were also reactive. Nonetheless, the least expression was seen in case of CD 43, where only five cases of AdCC were positive. Six cases of PA and three cases of PLGA were also positive. Our results suggest that the use of GFAP, SMA, CD 117 and CD 43 as an adjunct to histological examination is not helpful in differentiating PA, AdCC and PLGA from one another.

Radiography is one of the most valuable diagnostic tools used in comprehensive dental care. Although there is no safe level of radiation exposure, the possible risk associated with exposure to radiation, must be elucidated. To date, a variety of assays have been proposed to assess the mutagenic potential of genotoxicants; however, these methods are typically laborious and time consuming. The aim of the present study was to evaluate the possible genotoxic effect of routinely used panoramic radiation exposure in exfoliated epithelial cells as measured by the formation of micronuclei and to compare the genotoxicity of X-rays on keratinized epithelial gingival cells and the nonkeratinized buccal epithelial cells. The study included 53 healthy individuals with a mean age of 25.21 ±12.67 years. Specimens of exfoliated epithelial cells were collected from patients subjected to panoramic radiography before and 10 days after radiation exposure. The cells were stained with Giemsa and evaluated for micronuclei by scoring 1000 cells per slide. In our study, the genotoxic effect of radiation exposure from panoramic radiography showed a statistically significant increase in the MN frequency in buccal epithelial cells. A significant correlation was observed between the age of the subjects and micronuclei, although no such correlation was found between gender and micronuclei count. MN test serves as a simple biomarker indicating the direct exposure to DNA damaging agents such as ionizing radiation, emphasizing great sensitivity even for exposure to low doses during radiation screening. Thus, panoramic dental radiography should be cautiously used only when necessary.

The aim of this study was to assess the effect of bleaching on elution of monomers from nanofilled and microhybrid composites. 80 samples (5mm diameter and 3mm thickness) of each composite were prepared. After curing, half of them were randomly polished. Each group was divided into 8 subgroups and immersed in water or 10%, 20% and 30% H2O2 for 3 or 8 hours. Eluted Bis-GMA (Bis-phenol A Glycidyl Dimethacrylate), TEGDMA (Triethyleneglycol Dimethacrylate), UDMA (Urethane Dimethacrylate) and BisEMA (Bis-phenol A ethoxylate Dimethacrylate) were quantified by high performance liquid chromatography and the results were analyzed by univariate ANOVA and t-test (P<0.05). Bleach significantly increased the overall release of monomers (P<0.001); TEGDMA was released more than Bis-GMA (P<0.001). Supreme released more TEGDMA compared to Z250 (P<0.001). Bleaching increased the release of this monomer (P<0.001). Increasing both the concentration of H2O2, and the immersion time, increased the release of TEGDMA (P<0.001). Polishing had no effect on release of this monomer (P=0.952). Supreme released more Bis-GMA than Z250 (P=0.000). The more concentrated H2O2 caused more elution of Bis-GMA (P= 0.003); while the effect of immersion time was not significant (P=0.824). Polishing increased the release of Bis-GMA (P=0.001). Neither the type of composite nor Bleaching had any effect on release of UDMA (P=0.972) and (P=0.811) respectively. Immersion duration increased the release of UDMA (P=0.002), as well as polishing (P=0.024). Bleaching increased the release of monomers. Nanofilled composites released more monomer than the microfilled.

The number of scientific papers is a conventional metric to measure a country’s research performance in a particular area. The aim of this survey was to demonstrate statistical information about orthodontic research published in international and national journals. Pubmed as an international and IranMedex and SID as national databases were searched between1997 and 2012. The keyword searching method was used in English and Persian. Abstracts were reviewed and unrelated articles were omitted. Data were obtained and transferred to Microsoft Excel to survey the scintometric indicators. According to the defined criteria, a total of 733 papers were found showing a considerable increase. Five hundred papers (68.2%) were published in domestic journals, and 233 (31.8%) were published in PubMed indexed journals. Most of the orthodontic articles originated from Shahid Beheshti University of Medical Sciences (22.9%). The Journal of Dental School, Shahid Beheshti University of Medical Sciences published most of the national papers (27.8%) and the Australian Orthodontic Journal published the majority of international papers (9.9%) In terms of study design, 52.5% of the articles were observational and 39.4% were interventional. Orthodontic research production in Iran has made significant strides in the recent years and researchers should focus on the quality of the study in this field in order to apply research production in evidence base dentistry.

Several appliances have been used for palatal expansion for treatment of posterior cross bite. The purpose of this study was to evaluate the stress induced in the apical and crestal alveolar bone and the pattern of tooth displacement following expansion via removable expansion plates or fixed-banded palatal expander using the finite element method (FEM) analysis. Two 3D FEM models were designed from a mesio-distal slice of the maxilla containing the upper first molars, their periodontium and alveolar bone. Two palatal expanders (removable and fixed) were modeled. The models were designed in SolidWorks 2006 and then transferred to ANSYS Workbench. The appliance halves were displaced 0.1 mm laterally. The von Mises stress in the apical, crestal, and PDL areas and also the vertical displacement of the cusps (palatal and buccal) was were evaluated. The total PDL stress was 0.40003 MPa in the removable appliance (RA) model and 4.88e-2 MPa in the fixed appliance (FA) model and the apical stress was 9.9e-2 and 1.17e-2 MPa, respectively. The crestal stress was 2.99e-1 MPa in RA and 7.62e-2 MPa in the FA. The stress in the cortical bone crest was 0.30327 and 7.9244e-2 MPa for RA and FA, respectively and 3.7271 and 7.4373e-2 MPa in crestal area of spongy bone, respectively. The vertical displacement of the buccal cusp and palatal cusp was 1.64e-2 and 5.90e-2 mm in RA and 1.05e-4 and 1.7e-4 mm in FA, respectively. The overall stress as well as apical and crestal stress in periodontium of anchor teeth was higher in RA than FA; RA elicited higher stress in both cortical and spongy bone. The vertical displacement of molar cusps was more in removable than fixed palatal expander model.

The aim of this study was to evaluate the effect of cyclic loading on the bond strength of quartz fiber posts to root canal dentin after different surface treatments of different regions of root canal dentin. Forty-eight single-rooted human teeth were selected. Post spaces were prepared and then the teeth were divided into four groups: G1: no treatment (control); G2: irrigation with a chemical solvent; G3: etching with 37% phosphoric acid; G4: treatment with ultrasonic file. The fiber posts were cemented using dual-cured resin cement. Half of the specimens were load-cycled (10000 cycles, 3 cycles/s) and the others did not undergo any load cycling. From each root, two slides measuring 1 mm in thickness were obtained from the apical and cervical regions. The push-out bond strength test was performed for each slice. Data were analyzed by using 3-way ANOVA and Tukey HSD tests. The fracture modes were evaluated under a stereomicroscope at ×20. The effect of load cycling and surface treatment as the main factors and the interaction of main factors were not significant (P=0.734, P=0.180, and P=0.539, respectively). The most frequent failure mode under the stereomicroscope was adhesive. It appears that load cycling and surface treatment methods had no effect on the bond strength of fiber posts to root canal dentin, but it depended on the region of the root canal dentin.

C-shaped configuration in the upper maillary first molar is an extremely rare appearance (0.12%). This case reports management of the tooth with such a configuration as well as depiction of its internal morpholgy and external morphology through spiral computed tomography and dentascan in the contralateral tooth with similar morphology. After careful clinical observation and confirmation through spiral computed tomography, it was concluded that the teeth had Melton category I configuration with fused roots.

This clinical report describes a treatment option for replacement of a missing mandibular anterior tooth using InCeram resin bonded fixed partial denture (RBFPD). The conventional approach for replacing mandibular incisors dictates the placement of either a conventional porcelain-fused-to-metal (PFM) bridge, Maryland bridge, or fiber-reinforced composite veneer bridge and several appearance-related disadvantages have been reported in the use of a prosthesis that incorporates a metal substructure. The InCeram bridge is a minimally invasive restoration and eliminates undesirable incisal graying frequently observed in metal RBFPDs. This method was successfully clinically applied to overcome shortcomings of other approaches that may require a minimal invasive technique to preserve lasting sound tooth structure.

It is known that the mandibular first molar can display significant anatomical variations namely the number of root canals, the number of roots and morphology. Mandibular molars may sometimes have an additional root located lingually (the radix entomolaris) or buccally (the radix paramolaris). If encountered, an awareness and understanding of this unusual root and its canal morphology can contribute to the successful outcome of root canal treatment. This case report discusses endodontic treatment of a mandibular first molar with a radix entomolaris, which is a rare entity and poses as an endodontic dilemma for the clinician with respect to diagnosis and subsequent treatment. Clinicians should be aware of these unusual root morphologies in the mandibular first molar which needs strategic treatment as unfilled canals remain a nidus for infection and can compromise treatment outcome.

This clinical report describes a technique to improve support for sunken cheeks using magnet retained detachable acrylic cheek plumpers. The new generation of magnets with improved technology provides sufficient denture retention for clinical application. However, further follow-up may be necessary to ascertain the long-term usefulness of the magnet-retained prosthesis, because of corrosion and further loss of magnetism.