Spectrophotometric evaluation of staining of different types of light-cure composite resins after exposure with different light-cure intensities: An in vitro study.

Context: Relation between the adequate intensity output of curing lights on color stability of composite resin is well accepted. Aims: To investigate the effect of different light-curing intensities and its relation to color stability of different polymerized composite resin materials using the spectophotometric analysis. Settings and Design: Comparative in vitro study done on composite resin discs. Subjects and Methods: A total of 180 discs comprising sixty discs prepared from three different composite resins, namely microhybrid composite resin (Filtek Z100,3M ESPE), nanohybrid composite resin (Filtek Z250 XT, 3M ESPE), and nanofilled composite resin (Filtek Z350 XT,3M ESPE) using three different light curing intensities, viz., 325-425 mW/cm2, 750-850 mW/cm2, and 1000-1100 mW/cm2. Later these discs were stained with 2% methylene blue followed by re-absorption in absolute alcohol for supernatant solution preparation which is used for the spectrophotometric analysis. Statistical Analysis Used: Spectrophotometric absorption values were analyzed using the one-way ANOVA test for intergroup analysis. Results: Mean stain absorption was the highest with nanofilled composite resin (Filtek Z350 XT,3M ESPE) after exposure with light-curing intensity of 325-425 mW/cm2 and least with microhybrid composite resin (Filtek Z100, 3M ESPE) after exposure with light-curing intensity of 750-850 mW/cm2 and this difference found was highly significant statistically (P < 0.001). Conclusions: Microhybrid composite resin (Filtek Z100, 3M ESPE) cured with intensity of 750-850 mW/cm2 showed least stain absorption indication most color stability and esthetic function.

Evaluation of YouTube Videos as a Source of Information About Oral Self-examination to Detect Oral Cancer and Precancerous Lesions.

Objectives: The aim of this study was to investigate quality, reliability, and comprehensiveness of YouTube videos about oral self-examination to detect oral cancer and precancerous lesions and to assess whether the source, duration, quality, reliability, and/or comprehensiveness of videos influence their visibility and popularity. Materials and Methods: Videos on YouTube were searched using eight keywords similar to oral self-examination. The first 100 videos for each search term were included. Strict inclusion and exclusion criteria were adhered to, and videos were assessed for quality, reliability, and comprehensiveness. Upload date, views, likes, dislikes, duration, and source of the videos were noted. Viewing rate and interaction index were calculated for each video. Results: A total of 800 videos were analyzed, 24 of which met the inclusion criteria. Majority of videos (87%) were uploaded by the healthcare group. The visibility, quality, reliability, and comprehensiveness were higher in videos uploaded by the healthcare group when compared with the non-healthcare group, but not at a level of statistical significance. The mean interaction index score of the non-healthcare group was found to be higher than the healthcare group, with statistically significant difference. Duration of videos showed an impact on the comprehensiveness of the videos. Conclusion: There are relatively few videos on oral self-examination on YouTube, and most do not have satisfactory quality, reliability, and comprehensiveness. There is a potential to increase public awareness about oral self-examination by utilizing this tool. Videos with complete and accurate information regarding oral self-examination must be uploaded to YouTube, which is currently an important source of information for the general public.

Microcomputed tomographic evaluation of shaping ability of two thermo mechanically treated single-file systems in severely curved roots.

CONTEXT: Canal shaping abilities such as canal transportation, centering ability, and preparation time are important and have to be considered before using any Nickel-Titanium file system. AIM: This in vitro study aimed to evaluate and compare the amount of canal transportation, centering ability, and time required for the shaping of severely curved canals with WaveOne Gold (WOG) Primary Reciprocating file and One Curve (OC) Rotary file using the micro computed tomography (µCT). MATERIALS AND METHODS: Thirty intact mesial roots of extracted human mandibular first molars having severe curvature (25°-35°) were selected. Samples were divided into two groups. Samples in Group I and II were shaped with WOG primary reciprocating files and OC rotary files, respectively, to the working length. Time required to prepare each canal was recorded. µCT pre- and post-instrumentation scans of all samples were taken. The cross-sectional images at 3, 6, and 9 mm from the radiographic apex were selected for analysis. Statistical analysis was performed using the Kruskal-Wallis and unpaired t-test. RESULTS: At 3 mm, OC showed statistically lower canal transportation with mean value (0.17 ± 0.10) than WOG (0.55 ± 0.42). Furthermore, OC showed statistically significant better centering ability (0.59 ± 0.25) than WOG (0.39 ± 0.20) at 3 mm level. However, the differences between both instruments were not statistical significant at 6 and 9 mm level for canal transportation and centering ratio. WOG reciprocating file required less time for canal preparation than OC file. CONCLUSIONS: OC rotary file showed less canal transportation and better canal centring ability than WOG file, during the preparation of severely curved canals. However, WOG required less time for canal preparation.

Shear bond strength of composite resin to resin-modified glass ionomer cement using 2-hydroxyethyl methacrylate-based and 2-hydroxyethyl methacrylate-free adhesive system.

BACKGROUND: Sandwich technique combines the properties of both composite resin and glass ionomer cement to make the most of the physical and esthetic properties of each material. Bonding agents improve the wettability of GIC surface and improves the bond between composite resin and GIC. The aim of this study was to evaluate and compare shear bond strength of composite resin to resin modified glass ionomer cement using HEMA-based and HEMA-free adhesive systems. An in vitro study. MATERIALS AND METHODS: Total 30 disc-shaped samples were prepared with resin modified glass ionomer cement (RMGIC). Samples were divided into three groups, each group containing 10 samples. Group I (n=10): Nano-hybrid composite resin (NHCR) was bonded to RMGIC without any adhesive system. Group II (n=10): NHCR was bonded to RMGIC using hydroxyethylmethacrylate (HEMA)-based adhesive system. Group III (n=10): NHCR was bonded to RMGIC using HEMA-free adhesive system. The shear bond strength was tested using Universal testing Machine and the results were calculated using one way ANOVA and Post-Hoc test. RESULTS: Maximum shear bond strength was recorded in group III where HEMA-free adhesive used with a mean value of 6.13±1.859 MPa followed by group II where HEMA-based adhesive used with mean value of 4.38±1.533 MPa. The control group showed least shear bond strength. CONCLUSION: Application of HEMA-free adhesive (OptiBond All-In-One) resulted in greater shear bond strength between RMGIC and composite resin than HEMA-based adhesive (Single bond Universal Adhesive).

Antimicrobial Efficacy of Different Endodontic Sealers against Enterococcus faecalis: An In vitro Study.

OBJECTIVE: The aim of this in vitro study is to compare the antimicrobial efficacy of four different endodontic sealers against Enterococcus faecalis. MATERIAL AND METHOD: Four different endodontic sealers, namely, resin based (AH Plus), zinc oxide-eugenol based (Tubliseal), calcium hydroxide based (Sealapex), and mineral trioxide aggregate (MTA Fillapex) based were tested for their antimicrobial efficacy against E. faecalis using agar diffusion method. Four wells were made by the removal of agar at equidistant points and filled with freshly mixed respective root canal sealers and were inoculated with E. faecalis. All the three plates were incubated for a period of 72 h at 37°C under aerobic conditions. The diameter of inhibition zones was measured at 24, 48, and 72 h time intervals. Data obtained were statistically analyzed using one-way analysis of variance and unpaired t-test. RESULTS: All the tested sealers showed some bacterial growth inhibition of E. faecalis. Their efficacy in descending order of antibacterial activity was as follows: Sealapex > AH Plus > Tubliseal > MTA Fillapex. The efficacy of the root canal sealers decreased marginally with increase in their duration of action. CONCLUSION: Antimicrobial efficacy of calcium hydroxide-based sealer was highest followed by resin-based sealer and was the least with MTA based sealer.

Efficacy of new irrigating solution on smear layer removal in apical third of root canal: A scanning electron microscope study.

AIMS: The aim of this in vitro study is to evaluate and compare the smear layer removal efficacy of etidronic acid-based irrigating solution with others in the apical third of the root canal. MATERIALS AND METHODS: Forty human single-rooted mandibular premolar teeth were taken and decoronated to standardize the canal length. After biomechanical preparation, teeth were randomly divided into four groups (n = 10) and the final irrigation was carried out with tested irrigants. Group I: normal saline (negative control); Group II: 5.25% sodium hypochlorite (NaOCl) with surfactant and 17% ethylenediaminetetraacetic acid (EDTA) with surfactant; Group III: freshly mixed BioPure MTAD; and Group IV: freshly mixed Chloroquick solution. The teeth were split into two halves and observed under a scanning electron microscope to analyze the amount of smear layer present. STATISTICAL ANALYSIS: Data were analyzed using the Kruskal-Wallis test and Mann-Whitney test. RESULTS: Group II (5.25% NaOCl with surfactant followed by 17% EDTA with surfactant) showed least smear layer scores (1.1 ± 0.3162). This was followed by Group III (MTAD) (2.2 ± 0.4216) and then Group IV (Chloroquick) (2.4 ± 0.5164). CONCLUSION: Sequential use of 5.25% NaOCl with surfactant and 17% EDTA with surfactant was found to be the most efficient than MTAD and Chloroquick in the removal of smear layer in the apical third of root canal.

Comparative evaluation of root canal disinfection by conventional method and laser: an in vivo study.

OBJECTIVE: The aim of this study was to comparatively evaluate in vivo the disinfecting ability of conventional method and lasers in root canals. MATERIALS AND METHODS: Study criteria included 60 single rooted teeth, which were indicated for root canal therapy followed to dental caries and trauma with intact crowns. Such selected patients were randomly divided into 2 groups, namely, Group A (30 teeth) and Group B (30 teeth). All clinical procedures were carried out under strict aseptic precautions. The teeth in Group A were subjected to biomechanical preparation followed by the treatment with the help of diode laser containing the gallium aluminum and arsenic, which emitted 980 nm wavelengths. The teeth in Group B were treated with routine method of biomechanical preparation along with irrigation using sodium hypochlorite and hydrogen peroxide. The microbiological samples were taken immediately after the access preparation and after the completion of the root canal disinfection and were sent for microbiological analysis. RESULTS: The teeth in Group A showed presence of common strains of bacteria ranging from Streptococci, Staphylococci, Klebsiella, and Pseudomonas. Reduction in the growth of microorganisms was found for all types of microorganisms. Only 8 samples exhibited the growth after treatment with laser. Results of Group B also showed the presence of common strains of anaerobic and aerobic bacteria as shown in earlier studies, predominantly Staphylococcus, Streptococci, and Pseudomonas. Statistical analysis showed non-significant P values for the microorganisms; however, only 3 samples showed the growth after treatment with conventional technique using sodium hypochlorite and hydrogen peroxide. CONCLUSION: Conventional method by using sodium hypochlorite and hydrogen peroxide as irrigating solutions is highly effective in disinfecting the root canal. Lasers when used can also reduce the bacterial load of the infected root canal.

Osteosarcoma of the mandible mimicking an odontogenic abscess: a case report and review of the literature.

UNLABELLED: Inflammatory lesions, like periapical/odontogenic abscesses, are by far the most common pathologic condition of the jaws. Radiographically, these lesions commonly manifest as widening of periodontal ligament space, discontinuity of lamina dura and ill-defined periapical radiolucency. There are some rare disorders which could cause similar radiographic changes in the jaw bone. With careful scrutiny of periapical radiolucency, regular periodic follow-up radiographs and histo-pathologic examination, the periapical abscess or infection can be differentiated from rare fatal disorders. CLINICAL RELEVANCE: This paper highlights the need for vigilant examination of even the commonest, innocuous-appearing periapical changes which sometimes are produced by some rare fatal disorders.

The effect of environmental pressure changes on the retentive strength of cements for orthodontic bands.

OBJECTIVES: The purpose of this study was to evaluate the effect of environmental pressure changes on the retentive strength of orthodontic bands cemented with conventional glass ionomer cement or resin-modified glass ionomer cement. MATERIALS AND METHODS: Stainless steel bands were cemented to 80 extracted first and second molars in two equal groups comprising conventional glass ionomer cement and resin-modified glass ionomer cement. Each group was randomly divided into two sub-groups of 20 samples each, one sub-group to act as a control, and the other to be used experimentally. After seven days of storage, the experimental groups were subjected to simulated dives to 405 kPa [corrected] for 3 minutes, 15 times in a pressure pot, after which the force required to deband was tested using a universal testing machine. The data were statistically analysed using Student's t-tests, significance being assumed at P < 0.001. RESULTS: The retentive strength of bands cemented with conventional glass ionomer in the pressure-cycled group was statistically significantly less than that in the control group. No statistically significant difference in strength was found between the two groups cemented with resin-modified glass ionomer. CONCLUSIONS: This study showed that the retentive strength of bands cemented with conventional glass ionomer is reduced after pressure cycling. We suggest that dentists should consider using resin-modified glass ionomer cement for cementing orthodontic bands for patients who are divers and thus likely to be exposed to raised-pressure cycling.

Effect of the presence of dental plaque on oral sugar clearance and salivary pH: an in vivo study.

BACKGROUND: Fermentable carbohydrates and microorganisms in the plaque play a significant role in the pathogenesis of dental caries. Oral clearance of sugars and salivary pH is affected by the presence of plaque. AIMS AND OBJECTIVES: This study was conducted to study the effect of the presence of plaque on the salivary clearance of sucrose and on salivary pH. MATERIALS AND METHODS: The study design was of a randomized controlled parallel group clinical trial and included two groups: The control group and plaque group, as follows: Control group--subjects without plaque and plaque group--subjects with plaque. Salivary sucrose determination was done by using the anthrone technique. A digital pH meter estimated the salivary pH. The Student's t test and Mann-Whitney test was employed to compare the intergroup differences. Pearson's correlation coefficient was used for analysis. RESULTS: The salivary sucrose clearance time was increased by presence of plaque. CONCLUSION: The presence of plaque led to increased salivary sucrose concentrations and increased the salivary sucrose clearance time. CLINICAL SIGNIFICANCE: The dental caries is the dynamic relationship among the dental plaque microbiota, dietary carbohydrates, saliva and cariogenic potential of the dental plaque. Caries occur preferentially in the dentition sites characterized by high exposure to carbohydrate and diminished salivary effect.