Fracture resistance of endodontically treated maxillary premolars restored by silorane-based composite with or without fiber or nano-ionomer

Shafiei, Fereshteh,Tavangar, Maryam Sadat,Ghahramani, Yasamin,Fattah, Zahra The Korean Academy of Prosthodonitics 2014 The Journal of Advanced Prosthodontics Vol.6 No.3

PURPOSE. This in vitro study investigated the fracture resistance of endodontically treated premolars restored using silorane-or methacrylate-based composite along with or without fiber or nano-ionomer base. MATERIALS AND METHODS. Ninety-six intact maxillary premolars were randomly divided into eight groups (n = 12). G1 (negative control) was the intact teeth. In Groups 2-8, root canal treatment with mesio-occlusodistal preparation was performed. G2 (positive control) was kept unrestored. The other groups were restored using composite resin as follows: G3, methacrylate-based composite (Z250); G4, methacrylate composite (Z250) with polyethylene fiber; G5 and G6, silorane-based composite (Filtek P90) without and with the fiber, respectively; G7 and G8, methacrylate-and silorane-based composite with nano-ionomer base, respectively. After aging period and thermocycling for 1000 cycles, fracture strength was tested and fracture patterns were inspected. The results were analyzed using ANOVA and Tukey HSD tests (${\alpha}$=0.05). RESULTS. Mean fracture resistance for the eight groups (in Newton) were G1: $1200{\pm}169^a$, G2: $360{\pm}93^b$, G3: $632{\pm}196^c$, G4: $692{\pm}195^c$, G5: $917{\pm}159^d$, G6: $1013{\pm}125^{ad}$, G7: $959{\pm}148^d$, G8: $947{\pm}105^d$ (different superscript letters revealed significant difference among groups). Most of the fractures in all the groups were restorable, except Group 3. CONCLUSION. Silorane-based composite revealed significantly higher strength of the restored premolars compared to that of methacrylate one. Fiber insertion demonstrated no additional effect on the strength of both composite restorations; however, it increased the prevalence of restorable fracture of methacrylate-based composite restored teeth. Using nano-ionomer base under methacrylate-based composite had a positive effect on fracture resistance and pattern. Only fiber-reinforced silorane composite restoration resulted in a strength similar to that of the intact teeth.

Improvement of electronic properties of carboxylated zigzag single wall carbon nanotubes by interaction with benzene derivatives

Masood Hamadanian,Zahra Tavangar,Sara Naseh 한국물리학회 2015 Current Applied Physics Vol.15 No.12

In this article, we reported the structural and conductive properties of benzene derivatives/carboxylated zigzag SWCNTs. It was noticed that the carboxylated carbon nanotubes were appropriate adsorbents for benzene derivatives. We presented novel density of states and band structures for modified SWCNTs by both carboxylic group and benzene derivatives. The result showed that nitrobenzene/COOH-SWCNT comprising superb electronic properties can be effectually applied for electronic devices and solar cells, instead of aniline/SWCNT combined system.

Fracture resistance of endodontically treated maxillary premolars restored by silorane-based composite with or without fiber or nano-ionomer

Fereshteh Shafiei,Maryam Sadat Tavangar,Yasamin Ghahramani,Zahra Fattah 대한치과보철학회 2014 The Journal of Advanced Prosthodontics Vol.6 No.3

PURPOSE This in vitro study investigated the fracture resistance of endodontically treated premolars restored using silorane- or methacrylate-based composite along with or without fiber or nano-ionomer base. MATERIALS AND METHODS Ninety-six intact maxillary premolars were randomly divided into eight groups (n = 12). G1 (negative control) was the intact teeth. In Groups 2-8, root canal treatment with mesio-occlusodistal preparation was performed. G2 (positive control) was kept unrestored. The other groups were restored using composite resin as follows: G3, methacrylate-based composite (Z250); G4, methacrylate composite (Z250) with polyethylene fiber; G5 and G6, silorane-based composite (Filtek P90) without and with the fiber, respectively; G7 and G8, methacrylate- and silorane-based composite with nano-ionomer base, respectively. After aging period and thermocycling for 1000 cycles, fracture strength was tested and fracture patterns were inspected. The results were analyzed using ANOVA and Tukey HSD tests (α=0.05). RESULTS Mean fracture resistance for the eight groups (in Newton) were G1: 1200 ± 169a, G2: 360 ± 93b, G3: 632 ± 196c, G4: 692 ± 195c, G5: 917 ± 159d, G6: 1013 ± 125ad, G7: 959 ± 148d, G8: 947 ± 105d (different superscript letters revealed significant difference among groups). Most of the fractures in all the groups were restorable, except Group 3. CONCLUSION Silorane-based composite revealed significantly higher strength of the restored premolars compared to that of methacrylate one. Fiber insertion demonstrated no additional effect on the strength of both composite restorations; however, it increased the prevalence of restorable fracture of methacrylate-based composite restored teeth. Using nano-ionomer base under methacrylate-based composite had a positive effect on fracture resistance and pattern. Only fiber-reinforced silorane composite restoration resulted in a strength similar to that of the intact teeth.

The effects of noise reduction, sharpening, enhancement, and image magnification on diagnostic accuracy of a photostimulable phosphor system in the detection of non-cavitated approximal dental caries

Zahra Dalili Kajan,Reza Tayefeh Davalloo,Mayam Tavangar,Fatemeh Valizade 대한영상치의학회 2015 Imaging Science in Dentistry Vol.45 No.2

Purpose: Contrast, sharpness, enhancement, and density can be changed in digital systems. The important question is to what extent the changes in these variables affect the accuracy of caries detection. Materials and Methods: Forty eight extracted human posterior teeth with healthy or proximal caries surfaces were imaged using a photostimulable phosphor (PSP) sensor. All original images were processed using a six-step method: (1) applying “Sharpening 2” and “Noise Reduction” processing options to the original images; (2) applying the “Magnification 1:3” option to the image obtained in the first step; (3) enhancing the original images by using the “Diagonal/” option; (4) reviewing the changes brought about by the third step of image processing and then, applying “Magnification 1:3”; (5) applying “Sharpening UM” to the original images; and (6) analyzing the changes brought about by the fifth step of image processing, and finally, applying “Magnification 1:3.” Three observers evaluated the images. The tooth sections were evaluated histologically as the gold standard. The diagnostic accuracy of the observers was compared using a chi-squared test. Results: The accuracy levels irrespective of the image processing method ranged from weak (18.8%) to intermediate (54.2%), but the highest accuracy was achieved at the sixth image processing step. The overall diagnostic accuracy level showed a statistically significant difference (p=0.0001). Conclusion: This study shows that the application of “Sharpening UM” along with the “Magnification 1:3” processing option improved the diagnostic accuracy and the observer agreement more effectively than the other processing procedures.

The effects of noise reduction, sharpening, enhancement, and image magnification on diagnostic accuracy of a photostimulable phosphor system in the detection of non-cavitated approximal dental caries

Kajan, Zahra Dalili,Davalloo, Reza Tayefeh,Tavangar, Mayam,Valizade, Fatemeh Korean Academy of Oral and Maxillofacial Radiology 2015 Imaging Science in Dentistry Vol.45 No.2

Purpose: Contrast, sharpness, enhancement, and density can be changed in digital systems. The important question is to what extent the changes in these variables affect the accuracy of caries detection. Materials and Methods: Forty eight extracted human posterior teeth with healthy or proximal caries surfaces were imaged using a photostimulable phosphor (PSP) sensor. All original images were processed using a six-step method: (1) applying "Sharpening 2" and "Noise Reduction" processing options to the original images; (2) applying the "Magnification 1:3" option to the image obtained in the first step; (3) enhancing the original images by using the "Diagonal/"option; (4) reviewing the changes brought about by the third step of image processing and then, applying "Magnification 1:3"; (5) applying "Sharpening UM" to the original images; and (6) analyzing the changes brought about by the fifth step of image processing, and finally, applying "Magnification 1:3." Three observers evaluated the images. The tooth sections were evaluated histologically as the gold standard. The diagnostic accuracy of the observers was compared using a chi-squared test. Results: The accuracy levels irrespective of the image processing method ranged from weak (18.8%) to intermediate (54.2%), but the highest accuracy was achieved at the sixth image processing step. The overall diagnostic accuracy level showed a statistically significant difference (p=0.0001). Conclusion: This study shows that the application of "Sharpening UM" along with the "Magnification 1:3" processing option improved the diagnostic accuracy and the observer agreement more effectively than the other processing procedures.

Expression of Matrix Metalloproteinase-2, but not Caspase-3, Facilitates Distinction between Benign and Malignant Thyroid Follicular Neoplasms

Sanii, Sanaz,Saffar, Hiva,Tabriz, Hedieh M.,Qorbani, Mostafa,Haghpanah, Vahid,Tavangar, Seyed M. Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.5

Purpose: Definite diagnosis of follicular thyroid carcinoma (FTC) is based on the presence of capsular or vascular invasion. To date, no reliable and practical method has been introduced to discriminate this malignant neoplasm from follicular thyroid adenoma (FTA) in fine needle aspiration biopsy material. Matrix metalloproteinase-2 (MMP-2), by degrading extracellular matrix, and caspase-3, by induction of apoptosis, have been shown to play important roles in carcinogenesis and aggressive behavior in many tumor types. The aim of this study was to examine expression of MMP-2 and caspase-3 in thyroid follicular neoplasms and to determine their usefulness for differential diagnosis. Method: Sixty FTAs and 41 FTCs were analysed immunohistochemically for MMP-2 and caspase-3. Result: MMP-2 was positive in 4 FTCs (9.8%), but in none of FTAs, with statistical significance (p= 0.025). Caspase-3 was positive in 30 (50%) of FTAs and in 27 (65.9%) of FTCs. Conclusion: Our results show MMP-2 expression only in FTCs and suggest that this protein may be a useful marker to confirm diagnosis of FTC versus FTA with 100% specificity and 100% predictive value of a positive test. We failed to show any differential diagnostic value for caspase-3 in thyroid follicular neoplasms.

Hybrid argon plasma coagulation in Barrett’s esophagus: a systematic review and meta-analysis

Sagar N. Shah,Nabil El Hage Chehade,Amirali Tavangar,Alyssa Choi,Marc Monachese,Kenneth J. Chang,Jason B. Samarasena 대한소화기내시경학회 2023 Clinical Endoscopy Vol.56 No.1

Background/Aims: Patients with Barrett’s esophagus are at increased risk of developing esophageal adenocarcinoma. Endoscopic therapiesaim to eradicate dysplastic and metaplastic tissues. Hybrid argon plasma coagulation (hybrid-APC) utilizes submucosal fluid injectionto create a protective cushion prior to ablation that shields the submucosa from injury. We performed a pooled meta-analysis toevaluate the safety and efficacy of hybrid-APC. Methods: We conducted a systematic search of major electronic databases in April 2022. Studies that included patients with dysplasticand non-dysplastic Barrett’s esophagus undergoing treatment with hybrid-APC were eligible for inclusion. Outcome measures includedcomplete remission of intestinal metaplasia (CR-IM), stricture formation, serious adverse events, and number of sessions necessaryto achieve CR-IM. Results: Overall pooled CR-IM rate for patients undergoing hybrid-APC was 90.8% (95% confidence interval [CI], 0.872–0.939;I2=0%). Pooled stricture rate was 2.0% (95% CI, 0.005–0.042; I2=0%). Overall serious adverse event rate was 2.7% (95% CI, 0.007–0.055;I2=0%). Conclusions: Results of the current meta-analysis suggest that hybrid-APC is associated with high rates of CR-IM and a favorable safetyprofile. Interpretation of these results is limited by the inclusion of retrospective cohort and case series data. Randomized controlledtrials that standardize treatment and outcome evaluation protocols are necessary to understand how this treatment option is comparableto the current standards of care.