Comparing the EdgeFile X3, GenEndo, HeroGold, and ProTaper Gold Rotary Instruments Regarding the Effect of Different Concentrations and Temperature of NaOCl on Cyclic Fatigue Resistance.

AIM: This research was carried out with the objective of comparison between GenEndo, Protaper Gold, Hero Gold and EdgeFile X3 regarding the effect of different concentrations of NaOCl. MATERIALS AND METHODS: About 720 study specimens were included in the study. They were divided into four groups. Each group consisted of 180 files. Group A: GenEndo, Group B: Protaper Gold, Group C: Hero Gold, Group D: EdgeFile X3. Each group of instruments were further subdivided into nine subgroups (n = 20 for each subgroup). Testing of the cyclic fatigue was carried out in artificial canals which were prepared inside the blocks of stainless steel. The stainless steel blocks with artificial canals were established in a receiver that was packed with experimental solutions like distilled water, 5.25% NaOCl and 2.5% NaOCl. The adjustment of temperature was done at 25, 37, and 60°C. The rotation of the instrument was carried out inside the artificial canal as per the instructions of the manufacturer. The instrument was rotated until it got fractured. The time taken by the instrument to fracture was recorded in seconds. The number of cycles to fracture (NCF) was analyzed with the help of the equation (NCF = time to fracture × rpm/60). Surfaces at the site of fracture were examined with the help of a scanning electron microscope (EVOLS10, ZEISS) at magnification (300x and 2000x). RESULTS: It was noticed that there was a statistically significant increase in cyclic fatigue when sodium chloride was used as an endodontic irrigant instead of distilled water. The increase in cyclic fatigue was also observed when 5.25% sodium chloride was used instead of 2.5% sodium hypochlorite. Cyclic fatigue increased on change in temperature from 25 to 37°C and from 37 to 60°C. The difference was statistically significant (p < 0.05). It was observed that resistance against cyclic fatigue on treatment with different irrigation solutions at different temperatures was in the order of GenEndo > Protaper Gold > Hero Gold > EdgeFile X3. CONCLUSION: The resistance against cyclic fatigue in new NiTi rotary files can be affected significantly by different concentrations of sodium hypochlorite irrigant solution and the GenEndo rotary endodontic instrument has the maximum resistance against cyclic fatigue. CLINICAL SIGNIFICANCE: Irrigation of the root canal with irrigants, such as sodium hypochlorite (NaOCl) has been recommended strongly. NaOCl is used in the range of 0.5 and 6.5% concentration owing to its antimicrobial activity and tissue dissolution activities, particularly at higher temperatures. It has been postulated that fatigue of rotary endodontic instruments can be influenced by adjoining medium and their concentration.

Comparing Expansion of Maxillary Antrum between Periapical Surgery and Extraction of Permanent Maxillary First Molar in Pediatric Patients Using CBCT.

AIM: To compare the expansion of maxillary antrum between periapical surgery and extraction of permanent maxillary first molar in pediatric patients using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: In this study, 136 participants in the age-group of 11-18 years were included. The participants were divided into two groups. Group A consisted of patients who underwent extraction of the permanent maxillary first molars. Group B consisted of patients who underwent endodontic microsurgery in the periapical area. Group A included 68 participants while group B also included 68 study subjects. The expansion of the maxillary antrum was obtained after evaluating the change in volume of maxillary antrum at 6 months and 24 months in relation to the volume of maxillary antrum at the time of the procedure (baseline). For calculating the volume of the maxillary antrum, three parameters were taken into consideration. These parameters were an anteroposterior (AP) dimension, mesiodistal dimension (MD), and superoinferior (SI) dimension. Cone-beam computed tomography was used for carrying out these measurements with the help of Dolphin software. RESULTS: An expansion of 675.27 ± 32 mm3 was observed in group A between baseline and 6 months of extraction, while the expansion of 765.47 ± 24 mm3 was observed between 6 months and 24 months of extraction. This intragroup difference was statistically significant (p = 0.001). On the other hand, an expansion of 652.28 ± 43 mm3 was observed in group B between baseline and 6 months after periapical surgery and expansion of 969.43 ± 12 mm3 was observed between 6 months and 24 months after periapical endodontic surgery. This intragroup difference was statistically significant. In the control group, an expansion of 152.11 ± 12.101 mm3 was observed between baseline and 6 months after procedures while an expansion of 347.01 ± 6.781 mm3 was observed between 6 months and 24 months of procedures. The intragroup difference was significant statistically. CONCLUSION: In this study, expansion of maxillary antrum was observed in both extraction of the maxillary permanent first molar in pediatric patients and the periapical endodontic surgery, and the expansion of maxillary antrum was more in cases of periapical endodontic surgery; however, the difference was non-significant statistically. CLINICAL SIGNIFICANCE: Maxillary antrum expansion is clinically important during maxillary permanent tooth extraction or endodontic periapical surgery in pediatric patients because the growth of maxillary bones is in the growing stage in these patients. There are certain limitations of conventional two-dimensional (2D) radiographic techniques such as shortening, elongation, and superimposition of images. Recently, three-dimensional technique (3D) such as CBCT has been introduced in which these disadvantages have been eliminated.

Cure lies in nature: medicinal plants and endophytic fungi in curbing cancer.

Success of targeted cancer treatment modalities has generated an ambience of plausible cure for cancer. However, cancer remains to be the major cause of mortality across the globe. The emergence of chemoresistance, relapse after treatment and associated adverse effects has posed challenges to the present therapeutic regimes. Thus, investigating new therapeutic agents of natural origin and delineating the underlying mechanism of action is necessary. Since ages and still in continuum, the phytochemicals have been the prime source of identifying bioactive agents against cancer. They have been exploited for isolating targeted specific compounds to modulate the key regulating signaling pathways of cancer pathogenesis and progression. Capsaicin (alkaloid compound in chilli), catechin, epicatechin, epigallocatechin and epigallocatechin-3-gallate (phytochemicals in green tea), lutein (carotenoid found in yellow fruits), Garcinol (phenolic compound present in kokum tree) and many other naturally available compounds are also very valuable to develop the drugs to treat the cancer. An alternate repository of similar chemical diversity exists in the form of endophytic fungi inhabiting the medicinal plants. There is a high diversity of plant associated endophytic fungi in nature which are potent producers of anti-cancer compounds and offers even stronger hope for the discovery of an efficient anti-cancer drug. These fungi provide various bioactive molecules, such as terpenoids, flavonoids, alkaloids, phenolic compounds, quinines, steroids etc. exhibiting anti-cancerous property. The review discusses the relevance of phytochemicals in chemoprevention and as modulators of miRNA. The perspective advocates the imperative role of anti-cancerous secondary metabolites containing repository of endophytic fungi, as an alternative route of drug discovery.

Tear film surface quality with rigid and soft contact lenses.

OBJECTIVES: The aim of this study was to measure tear film surface quality (TFSQ) using dynamic high-speed videokeratoscopy during short-term (8 hrs) use of rigid and soft contact lenses. METHODS: A group of 14 subjects wore 3 different types of contact lenses on 3 different nonconsecutive days (order randomized) in 1 eye only. The subjects were screened to exclude those with dry eye. The lenses included a polymethyl methacrylate (PMMA) hard, a rigid gas permeable (RGP; Boston XO), and a soft silicone hydrogel lens. Three 30-second long high-speed videokeratoscopy recordings were taken with contact lenses in situ, in the morning and again after 8 hrs of contact lens wear, both in normal and suppressed blinking conditions. Recordings were also made on a baseline day with no contact lens wear. RESULTS: The presence of a contact lens in the eye had a significant effect on the mean TFSQ in both natural and suppressed blinking conditions (P=0.001 and P=0.01, respectively, repeated-measures analysis of variance). The TFSQ was worse with all the lenses compared with no lens in the eye in the afternoon during both normal and suppressed blinking conditions (all P<0.05). In natural blinking conditions, the mean TFSQ for the PMMA and RGP lenses was significantly worse than the baseline day (no lens) for both morning and afternoon measures (P<0.05). CONCLUSIONS: This study shows that both rigid and soft contact lenses adversely affect the TFSQ in both natural and suppressed blinking conditions. No significant differences were found between the lens types and materials.

Corneal changes following short-term rigid contact lens wear.

PURPOSE: The aim of this cross-over study was to investigate the changes in corneal thickness, anterior and posterior corneal topography, corneal refractive power and ocular wavefront aberrations, following the short term use of rigid contact lenses. METHOD: Fourteen participants wore 4 different types of contact lenses (RGP lenses of 9.5mm and 10.5mm diameter, and for comparison a PMMA lens of 9.5mm diameter and a soft silicone hydrogel lens) on 4 different days for a period of 8h on each day. Measures were collected before and after contact lens wear and additionally on a baseline day. RESULTS: Anterior corneal curvature generally showed a flattening with both of the RGP lenses and a steepening with the PMMA lens. A significant negative correlation was found between the change in corneal swelling and central and peripheral posterior corneal curvature (all p ≤ 0.001). RGP contact lenses caused a significant decrease in corneal refractive power (hyperopic shift) of approximately 0.5D. The PMMA contact lenses caused the greatest corneal swelling in both the central (27.92 ± 15.49 µm, p<0.001) and peripheral (17.78 ± 12.11 µm, p=0.001) corneal regions, a significant flattening of the posterior cornea and an increase in ocular aberrations (all p ≤ 0.05). CONCLUSION: The corneal swelling associated with RGP lenses was relatively minor, but there was slight central corneal flattening and a clinically significant hyperopic change in corneal refractive power after the first day of lens wear. The PMMA contact lenses resulted in significant corneal swelling and reduced optical performance of the cornea.

Regional changes in corneal thickness and shape with soft contact lenses.

PURPOSE: To investigate the influence of soft contact lenses on regional variations in corneal thickness and shape while taking account of natural diurnal variations in these corneal parameters. METHODS: Twelve young, healthy subjects wore four different types of soft contact lenses on four different days. The lenses were of two different materials (silicone hydrogel or hydrogel), designs (spherical or toric), and powers (3.00 or -7.00 diopter). Corneal thickness and topography measurements were taken before and after 8 h of lens wear and on 2 days without lens wear, using the Pentacam HR system. RESULTS.: The hydrogel toric contact lens caused the greatest level of corneal thickening in the central (20.3 +/- 10.0 microm) and peripheral cornea (24.1 +/- 9.1 microm) (p < 0.001) with an obvious regional swelling of the cornea beneath the stabilizing zones. The anterior corneal surface generally showed slight flattening. All contact lenses resulted in central posterior corneal steepening, and this was weakly correlated with central corneal swelling (p = 0.03) and peripheral corneal swelling (p = 0.01). CONCLUSIONS: There was an obvious regional corneal swelling apparent after wear of the hydrogel soft toric lenses because of the location of the thicker stabilization zones of the toric lenses. However, with the exception of the hydrogel toric lens, the magnitude of corneal swelling induced by the contact lenses over the 8 h of wear was less than the natural diurnal thinning of the cornea over this same period.