Ležaja, Maja

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  • Ležaja, Maja (6)
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Author's Bibliography

Effect of resin and photoinitiator on color, translucency and color stability of conventional and low-shrinkage model composites

Manojlović, Dragica; Dramićanin, Miroslav D.; Ležaja, Maja; Pongprueksa, Pong; Van Meerbeek, Bart; Miletić, Vesna

(Elsevier Sci Ltd, Oxford, 2016)

TY  - JOUR
AU  - Manojlović, Dragica
AU  - Dramićanin, Miroslav D.
AU  - Ležaja, Maja
AU  - Pongprueksa, Pong
AU  - Van Meerbeek, Bart
AU  - Miletić, Vesna
PY  - 2016
UR  - https://smile.stomf.bg.ac.rs/handle/123456789/2145
AB  - Objective. To study the effect of a low-shrinkage methacrylate monomer and monoacylphosphine oxide photoinitiator on color, translucency, and color stability of model resin-based composites (RBCs). Methods. Four micro-hybrid RBCs were prepared containing barium-glass fillers in bisphenol A-glycidyl-methacrylate (BisGMA) and triethyleneglycol-dimethacrylate (TEGDMA) or urethane-based low-shrinkage monomer FIT-852 (FIT; Esstech Inc.) and TEGDMA matrix. Camphorquinone (CQ)/amine or Lucirin TPO were used as photoinitiators. Commercial low-shrinkage RBCs (Charisma Diamond, Heraeus Kulzer and N'Durance, Septodont) and conventional RBCs (Tetric EvoCeram, Ivoclar Vivadent and Filtek Z250, 3M ESPE) were used as controls. Color and translucency were measured using Thermo Scientific Evolution (Thermo Fisher Scientific) and SpectroShade (TM) Micro (MHT Optic Research) spectrophotometers. Color stability was evaluated after immersion in black tea (pure, with milk or lemon) and distilled water. Data were analyzed using analyses of variance with Tukey's post-test (alpha = 0.05). Results. Photoinitiators had no significant effect on baseline color. Initially whiter FIT-based RBCs showed greater staining in all staining solutions than BisGMA-based RBCs. TPO-containing RBCs showed better color stability than CQ-containing RBCs irrespective of the base monomer. Tea and tea with lemon induced greatest color changes. Adding milk to tea significantly reduced material staining. Significance. Urethane-based low-shrinkage monomer FIT and conventional BisGMA affected color, translucency and color stability of their respective RBCs. Despite being used in posterior teeth, low-shrinkage RBCs are expected to have favorable optical and esthetic properties. Manufacturers are urged to provide information on optical properties of monomers and monomer mixtures in their low-shrinkage RBCs to allow understanding of interaction with fillers and photoinitiators.
PB  - Elsevier Sci Ltd, Oxford
T2  - Dental Materials
T1  - Effect of resin and photoinitiator on color, translucency and color stability of conventional and low-shrinkage model composites
VL  - 32
IS  - 2
SP  - 183
EP  - 191
DO  - 10.1016/j.dental.2015.11.027
ER  - 
@article{
author = "Manojlović, Dragica and Dramićanin, Miroslav D. and Ležaja, Maja and Pongprueksa, Pong and Van Meerbeek, Bart and Miletić, Vesna",
year = "2016",
abstract = "Objective. To study the effect of a low-shrinkage methacrylate monomer and monoacylphosphine oxide photoinitiator on color, translucency, and color stability of model resin-based composites (RBCs). Methods. Four micro-hybrid RBCs were prepared containing barium-glass fillers in bisphenol A-glycidyl-methacrylate (BisGMA) and triethyleneglycol-dimethacrylate (TEGDMA) or urethane-based low-shrinkage monomer FIT-852 (FIT; Esstech Inc.) and TEGDMA matrix. Camphorquinone (CQ)/amine or Lucirin TPO were used as photoinitiators. Commercial low-shrinkage RBCs (Charisma Diamond, Heraeus Kulzer and N'Durance, Septodont) and conventional RBCs (Tetric EvoCeram, Ivoclar Vivadent and Filtek Z250, 3M ESPE) were used as controls. Color and translucency were measured using Thermo Scientific Evolution (Thermo Fisher Scientific) and SpectroShade (TM) Micro (MHT Optic Research) spectrophotometers. Color stability was evaluated after immersion in black tea (pure, with milk or lemon) and distilled water. Data were analyzed using analyses of variance with Tukey's post-test (alpha = 0.05). Results. Photoinitiators had no significant effect on baseline color. Initially whiter FIT-based RBCs showed greater staining in all staining solutions than BisGMA-based RBCs. TPO-containing RBCs showed better color stability than CQ-containing RBCs irrespective of the base monomer. Tea and tea with lemon induced greatest color changes. Adding milk to tea significantly reduced material staining. Significance. Urethane-based low-shrinkage monomer FIT and conventional BisGMA affected color, translucency and color stability of their respective RBCs. Despite being used in posterior teeth, low-shrinkage RBCs are expected to have favorable optical and esthetic properties. Manufacturers are urged to provide information on optical properties of monomers and monomer mixtures in their low-shrinkage RBCs to allow understanding of interaction with fillers and photoinitiators.",
publisher = "Elsevier Sci Ltd, Oxford",
journal = "Dental Materials",
title = "Effect of resin and photoinitiator on color, translucency and color stability of conventional and low-shrinkage model composites",
volume = "32",
number = "2",
pages = "183-191",
doi = "10.1016/j.dental.2015.11.027"
}
Manojlović, D., Dramićanin, M. D., Ležaja, M., Pongprueksa, P., Van Meerbeek, B.,& Miletić, V.. (2016). Effect of resin and photoinitiator on color, translucency and color stability of conventional and low-shrinkage model composites. in Dental Materials
Elsevier Sci Ltd, Oxford., 32(2), 183-191.
https://doi.org/10.1016/j.dental.2015.11.027
Manojlović D, Dramićanin MD, Ležaja M, Pongprueksa P, Van Meerbeek B, Miletić V. Effect of resin and photoinitiator on color, translucency and color stability of conventional and low-shrinkage model composites. in Dental Materials. 2016;32(2):183-191.
doi:10.1016/j.dental.2015.11.027 .
Manojlović, Dragica, Dramićanin, Miroslav D., Ležaja, Maja, Pongprueksa, Pong, Van Meerbeek, Bart, Miletić, Vesna, "Effect of resin and photoinitiator on color, translucency and color stability of conventional and low-shrinkage model composites" in Dental Materials, 32, no. 2 (2016):183-191,
https://doi.org/10.1016/j.dental.2015.11.027 . .
43
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37

Shear bond strength to dentine of dental adhesives containing hydroxyapatite nano-fillers

Ležaja, Maja; Jokić, Bojan; Veljović, Đorđe; Miletić, Vesna

(Taylor & Francis Ltd, Abingdon, 2016)

TY  - JOUR
AU  - Ležaja, Maja
AU  - Jokić, Bojan
AU  - Veljović, Đorđe
AU  - Miletić, Vesna
PY  - 2016
UR  - https://smile.stomf.bg.ac.rs/handle/123456789/2100
AB  - The aim of this study was to compare the effect of hydroxyapatite (HAP) nano-rods (HAP rods) and HAP nano-sticks (HAP sticks) added to commercial adhesives on the macro-shear bond strength (SBS) to dentine and morphology of the adhesive-dentine interface. HAP was added to Single Bond Universal (SBU, 3M ESPE) and Te-Econom Bond (TeE; Ivoclar Vivadent), in the form of water suspensions to avoid agglomeration of nano-particles and to achieve HAP concentrations of 0.5, 1.0 and 1.5 wt%. Following a 'total-etch' or a 'self-etch' protocol, the adhesives were applied to flat dentine surface of 162 intact human, third molars (N = 6/group). Composite (Z250, 3M ESPE) was built-up using a split stainless steel mould, 3 mm in diameter. SBS was tested using a universal testing machine at 1 mm/min until fracture. Data were statistically analysed using two-way and one-way analysis of variance with Tukey's post-test (alpha = 0.05). HAP(rods) had no significant effect on SBS of the tested adhesives while HAP(sticks) improved bond strength to dentine only of adhesives applied following the 'total-etch' total-etch protocol. SBS values of SBU containing 1% HAP(sticks) (15.10 +/- 2.96 MPa) and TeE containing 0.5% HAP(sticks) applied following the total-etch protocol (12.96 +/- 4.48 MPa) were higher than those of their respective control groups (10.36 +/- 2.68 and 7.97 +/- 3.64 MPa). Samples with higher SBS showed more 'mixed' failures. HAP nano-fillers may improve bond strength of total-etch adhesives without an adverse effect on adhesive dispersion on dentine and its ability to infiltrate dentinal tubules.
PB  - Taylor & Francis Ltd, Abingdon
T2  - Journal of Adhesion Science & Technology
T1  - Shear bond strength to dentine of dental adhesives containing hydroxyapatite nano-fillers
VL  - 30
IS  - 24
SP  - 2678
EP  - 2689
DO  - 10.1080/01694243.2016.1197086
ER  - 
@article{
author = "Ležaja, Maja and Jokić, Bojan and Veljović, Đorđe and Miletić, Vesna",
year = "2016",
abstract = "The aim of this study was to compare the effect of hydroxyapatite (HAP) nano-rods (HAP rods) and HAP nano-sticks (HAP sticks) added to commercial adhesives on the macro-shear bond strength (SBS) to dentine and morphology of the adhesive-dentine interface. HAP was added to Single Bond Universal (SBU, 3M ESPE) and Te-Econom Bond (TeE; Ivoclar Vivadent), in the form of water suspensions to avoid agglomeration of nano-particles and to achieve HAP concentrations of 0.5, 1.0 and 1.5 wt%. Following a 'total-etch' or a 'self-etch' protocol, the adhesives were applied to flat dentine surface of 162 intact human, third molars (N = 6/group). Composite (Z250, 3M ESPE) was built-up using a split stainless steel mould, 3 mm in diameter. SBS was tested using a universal testing machine at 1 mm/min until fracture. Data were statistically analysed using two-way and one-way analysis of variance with Tukey's post-test (alpha = 0.05). HAP(rods) had no significant effect on SBS of the tested adhesives while HAP(sticks) improved bond strength to dentine only of adhesives applied following the 'total-etch' total-etch protocol. SBS values of SBU containing 1% HAP(sticks) (15.10 +/- 2.96 MPa) and TeE containing 0.5% HAP(sticks) applied following the total-etch protocol (12.96 +/- 4.48 MPa) were higher than those of their respective control groups (10.36 +/- 2.68 and 7.97 +/- 3.64 MPa). Samples with higher SBS showed more 'mixed' failures. HAP nano-fillers may improve bond strength of total-etch adhesives without an adverse effect on adhesive dispersion on dentine and its ability to infiltrate dentinal tubules.",
publisher = "Taylor & Francis Ltd, Abingdon",
journal = "Journal of Adhesion Science & Technology",
title = "Shear bond strength to dentine of dental adhesives containing hydroxyapatite nano-fillers",
volume = "30",
number = "24",
pages = "2678-2689",
doi = "10.1080/01694243.2016.1197086"
}
Ležaja, M., Jokić, B., Veljović, Đ.,& Miletić, V.. (2016). Shear bond strength to dentine of dental adhesives containing hydroxyapatite nano-fillers. in Journal of Adhesion Science & Technology
Taylor & Francis Ltd, Abingdon., 30(24), 2678-2689.
https://doi.org/10.1080/01694243.2016.1197086
Ležaja M, Jokić B, Veljović Đ, Miletić V. Shear bond strength to dentine of dental adhesives containing hydroxyapatite nano-fillers. in Journal of Adhesion Science & Technology. 2016;30(24):2678-2689.
doi:10.1080/01694243.2016.1197086 .
Ležaja, Maja, Jokić, Bojan, Veljović, Đorđe, Miletić, Vesna, "Shear bond strength to dentine of dental adhesives containing hydroxyapatite nano-fillers" in Journal of Adhesion Science & Technology, 30, no. 24 (2016):2678-2689,
https://doi.org/10.1080/01694243.2016.1197086 . .
11
8
12

Bond strength of restorative materials to hydroxyapatite inserts and dimensional changes of insert-containing restorations during polymerization

Ležaja, Maja; Veljović, Đorđe; Manojlović, Dragica; Milošević, Miloš; Mitrović, Nenad; Janaćković, Đorđe; Miletić, Vesna

(Elsevier Sci Ltd, Oxford, 2015)

TY  - JOUR
AU  - Ležaja, Maja
AU  - Veljović, Đorđe
AU  - Manojlović, Dragica
AU  - Milošević, Miloš
AU  - Mitrović, Nenad
AU  - Janaćković, Đorđe
AU  - Miletić, Vesna
PY  - 2015
UR  - https://smile.stomf.bg.ac.rs/handle/123456789/1962
AB  - Objective. To determine the shear bond strength (SBS) between synthetic controlled porous hydroxyapatite (HAP) inserts and restorative materials and dimensional changes of insert-containing restorations during curing. Methods. Cylinder-shaped HAP inserts (4 mm in diameter, 1.6 mm thick) were cemented in dentin discs (5 mm x 1.6 mm), cut mid-coronally from human third molars, using one of the following materials: universal microhybrid composite Filtek Z250, flowable composite Filtek Ultimate or glass-ionomer Vitrebond (all 3M ESPE). SBS of the same materials to HAP inserts was tested in a universal testing machine. Three-dimensional digital image correlation system Aramis (GOM) was used to measure strains and displacements. Data were statistically analyzed using one-way ANOVA with Tukey's post-test (alpha = 0.05). Results. SBS of restorative materials to HAP inserts ranged between 12.2 +/- 2.1 MPa (Filtek Z250) and 0.7 +/- 0.4 MPa (Filtek Z250 without an adhesive). The 'total-etch' approach of adhesive application significantly increased SBS of both Filtek Z250 (12.2 +/- 2.1 MPa) and Filtek Ultimate flowable (9.5 +/- 2.5 MPa) compared to the 'self-etch' approach (8.2 +/- 1.6 MPa and 4.4 +/- 0.9 MPa, respectively) (p  lt  0.05). HAP inserts reduced polymerization shrinkage to below 0.5% as well as displacements in the central region of the restorations. Peripheral shrinkage of restorative materials was similar with and without HAP inserts as were displacements of Filtek Z250 and Vitrebond. Significance. Replacing major part of dentin clinically, especially in large cavities, HAP inserts may shorten clinical working time, improve dimensional stability of the restoration by reducing central shrinkage and displacements and provide adhesive bonding to universal composites following a 'total-etch' approach.
PB  - Elsevier Sci Ltd, Oxford
T2  - Dental Materials
T1  - Bond strength of restorative materials to hydroxyapatite inserts and dimensional changes of insert-containing restorations during polymerization
VL  - 31
IS  - 2
SP  - 171
EP  - 181
DO  - 10.1016/j.dental.2014.11.017
ER  - 
@article{
author = "Ležaja, Maja and Veljović, Đorđe and Manojlović, Dragica and Milošević, Miloš and Mitrović, Nenad and Janaćković, Đorđe and Miletić, Vesna",
year = "2015",
abstract = "Objective. To determine the shear bond strength (SBS) between synthetic controlled porous hydroxyapatite (HAP) inserts and restorative materials and dimensional changes of insert-containing restorations during curing. Methods. Cylinder-shaped HAP inserts (4 mm in diameter, 1.6 mm thick) were cemented in dentin discs (5 mm x 1.6 mm), cut mid-coronally from human third molars, using one of the following materials: universal microhybrid composite Filtek Z250, flowable composite Filtek Ultimate or glass-ionomer Vitrebond (all 3M ESPE). SBS of the same materials to HAP inserts was tested in a universal testing machine. Three-dimensional digital image correlation system Aramis (GOM) was used to measure strains and displacements. Data were statistically analyzed using one-way ANOVA with Tukey's post-test (alpha = 0.05). Results. SBS of restorative materials to HAP inserts ranged between 12.2 +/- 2.1 MPa (Filtek Z250) and 0.7 +/- 0.4 MPa (Filtek Z250 without an adhesive). The 'total-etch' approach of adhesive application significantly increased SBS of both Filtek Z250 (12.2 +/- 2.1 MPa) and Filtek Ultimate flowable (9.5 +/- 2.5 MPa) compared to the 'self-etch' approach (8.2 +/- 1.6 MPa and 4.4 +/- 0.9 MPa, respectively) (p  lt  0.05). HAP inserts reduced polymerization shrinkage to below 0.5% as well as displacements in the central region of the restorations. Peripheral shrinkage of restorative materials was similar with and without HAP inserts as were displacements of Filtek Z250 and Vitrebond. Significance. Replacing major part of dentin clinically, especially in large cavities, HAP inserts may shorten clinical working time, improve dimensional stability of the restoration by reducing central shrinkage and displacements and provide adhesive bonding to universal composites following a 'total-etch' approach.",
publisher = "Elsevier Sci Ltd, Oxford",
journal = "Dental Materials",
title = "Bond strength of restorative materials to hydroxyapatite inserts and dimensional changes of insert-containing restorations during polymerization",
volume = "31",
number = "2",
pages = "171-181",
doi = "10.1016/j.dental.2014.11.017"
}
Ležaja, M., Veljović, Đ., Manojlović, D., Milošević, M., Mitrović, N., Janaćković, Đ.,& Miletić, V.. (2015). Bond strength of restorative materials to hydroxyapatite inserts and dimensional changes of insert-containing restorations during polymerization. in Dental Materials
Elsevier Sci Ltd, Oxford., 31(2), 171-181.
https://doi.org/10.1016/j.dental.2014.11.017
Ležaja M, Veljović Đ, Manojlović D, Milošević M, Mitrović N, Janaćković Đ, Miletić V. Bond strength of restorative materials to hydroxyapatite inserts and dimensional changes of insert-containing restorations during polymerization. in Dental Materials. 2015;31(2):171-181.
doi:10.1016/j.dental.2014.11.017 .
Ležaja, Maja, Veljović, Đorđe, Manojlović, Dragica, Milošević, Miloš, Mitrović, Nenad, Janaćković, Đorđe, Miletić, Vesna, "Bond strength of restorative materials to hydroxyapatite inserts and dimensional changes of insert-containing restorations during polymerization" in Dental Materials, 31, no. 2 (2015):171-181,
https://doi.org/10.1016/j.dental.2014.11.017 . .
19
10
21

Composites and adhesives with synthetic hydroxyapatite fillers and hydroxyapatite inserts : evaluation of mechanical properties and the quality of the adhesive bond

Ležaja, Maja

(Univerzitet u Beogradu, Stomatološki fakultet, 2015)

TY  - THES
AU  - Ležaja, Maja
PY  - 2015
UR  - http://eteze.bg.ac.rs/application/showtheses?thesesId=2742
UR  - https://fedorabg.bg.ac.rs/fedora/get/o:10884/bdef:Content/download
UR  - http://vbs.rs/scripts/cobiss?command=DISPLAY&base=70036&RID=47641359
UR  - http://nardus.mpn.gov.rs/123456789/5122
UR  - https://smile.stomf.bg.ac.rs/handle/123456789/983
AB  - Calcium hydroxyapatite (HAP) is an essential and dominant constituent of mineralized dental tissues. As such, HAP is a preferable component of dental materials for tooth restoration. Dental composites adhesively attached to dentin and enamel are the most frequently used restorative materials in contemporary aesthetic dentistry. However, polymerization shrinkage and the associated shrinkage stress remain the main disadvantages of composite materials. This doctoral thesis aimed to investigate the effect of HAP fillers in composites and adhesives on their mechanical properties and interaction with dentin, as well as to develop and test HAP-based inserts as potential dentin restoratives. The effect of partial replacement of conventional glass fillers with one of five shapes of HAP fillers (nano-HAP, micron-sized HAP particles: spheres with and without silicon doping or whiskers with and without silicon doping) in experimental composites was tested initially and after artificial „aging‟ in terms of the degree of conversion, Vickers hardness, flexural strength, flexural modulus, compressive strength and compressive modulus. Optimal weight percentage of HAP fillers was obtained through pilot studies. Additionally, two shapes of nano-HAP particles (nano-rods and nano-whiskers) were added in commercial adhesives in the form of suspensions with 0.5-1.5 wt% of HAP. Macroshear bond strength to dentin was tested and the morphology of adhesive interaction was analyzed microscopically. In the third part of this thesis, the effect of HAP-based inserts (standardized inlays) on polymerization shrinkage and displacements of restorations was investigated using the digital image correlation method based on two cameras for obtaining three-dimensional information. The restorations were prepared by cementing HAP inserts in standardized dentin discs with a universal or a flowable composite, or a resin-modified glass-ionomer cement. Bond strength to the aforementioned materials was also tested. HAP fillers were comparable to conventional glass fillers in terms of mechanical properties. HAP spheres even improved mechanical properties of experimental composites initially and after storage in Hank‟s balanced salt solution during 4 weeks...
AB  - Kalcijum hidroksiapatit (HAP) čini osnovnu mineralnu komponentu čvrstih zubnih tkiva pa kao takav predstavlja poţeljnu komponentu materijala koji izgubljena zubna tkiva treba da nadoknade. U eri estetske stomatologije najzastupljeniji restaurativni materijali su kompoziti adhezivno vezani za tvrda zubna tkiva. Osnovni nedostatak kompozitnih materijala i dalje predstavlja polimerizaciona kontrakcija, koja uzrokuje stvaranje napona u materijalu i dovodi do nastanka mikropukotine na njihovom spoju sa zubnim tkivima. Cilj ove doktorske disertacije bio je da se ispita uticaj HAP punilaca u kompozitima i adhezivima na njihova mehanička svojstva i vezu sa dentinom, kao i pravljenje i testiranje inserata na bazi HAP-a kao potencijalnih dentinskih zamenika. Testiran je uticaj zamene dela staklenih punilaca jednim od pet oblika HAP punilaca (nanočestičnim, mikročestičnim: sferama sa i bez dopiranja silicijumom i trakama sa i bez dopiranja silicijumom), na stepen konverzije, tvrdoću po Vikersu, savojnu čvrstoću, savojni moduo elastičnosti, kompresivnu čvrstoću i kompresivni moduo elastičnosti eksperimentalnih kompozita, inicijalno i nakon „starenja‟. Optimalan maseni udeo punilaca na bazi HAP-a odreĎen je pilot studijama. Osim toga, dva oblika nanočestičnog HAP-a (u obliku nano-iglica i nano-traka) u udelima 0,5-1,5 mas% su u obliku suspenzije dodavana u komercijalne adhezive, nakon čega je testom makrosmicanja ispitana jačina veze, a skenirajućom elektronskom mikroskopijom morfologija interakcije dobijenih adheziva sa dentinom. U trećem delu studije ispitivan je uticaj primene inserata na bazi HAP-a (standardizovani inleji) na zapreminsku kontrakciju i pomeranje materijala metodom korelacije digitalnih slika sa korišćenjem sistema dve kamere za trodimenzionalno merenje, kod restauracija koje su činili inserti u kombinaciji sa univerzalnim ili tečnim kompozitom, odnosno smolom modifikovanim glas jonomer cementom. TakoĎe je merena jačina veze HAP inserata sa pomenutim materijalima. HAP punioci svojim mehaničkim svojstvima mogu da pariraju najčešće korišćenim staklenim puniocima, pri čemu su HAP sfere pozitivno uticale na mehanička svojstva testiranih materijala, kao inicijalno, tako i nakon „starenja‟ u Henkovom rastvoru tokom 4 nedelje...
PB  - Univerzitet u Beogradu, Stomatološki fakultet
T1  - Composites and adhesives with synthetic hydroxyapatite fillers and hydroxyapatite inserts : evaluation of mechanical properties and the quality of the adhesive bond
T1  - Kompoziti i adhezivi sa sintetskim hidroksiapatitnim puniocima i hidroksiapatitni inserti : ispitivanje mehaničkih svojstava i kvaliteta adhezivne veze
UR  - https://hdl.handle.net/21.15107/rcub_nardus_5122
ER  - 
@phdthesis{
author = "Ležaja, Maja",
year = "2015",
abstract = "Calcium hydroxyapatite (HAP) is an essential and dominant constituent of mineralized dental tissues. As such, HAP is a preferable component of dental materials for tooth restoration. Dental composites adhesively attached to dentin and enamel are the most frequently used restorative materials in contemporary aesthetic dentistry. However, polymerization shrinkage and the associated shrinkage stress remain the main disadvantages of composite materials. This doctoral thesis aimed to investigate the effect of HAP fillers in composites and adhesives on their mechanical properties and interaction with dentin, as well as to develop and test HAP-based inserts as potential dentin restoratives. The effect of partial replacement of conventional glass fillers with one of five shapes of HAP fillers (nano-HAP, micron-sized HAP particles: spheres with and without silicon doping or whiskers with and without silicon doping) in experimental composites was tested initially and after artificial „aging‟ in terms of the degree of conversion, Vickers hardness, flexural strength, flexural modulus, compressive strength and compressive modulus. Optimal weight percentage of HAP fillers was obtained through pilot studies. Additionally, two shapes of nano-HAP particles (nano-rods and nano-whiskers) were added in commercial adhesives in the form of suspensions with 0.5-1.5 wt% of HAP. Macroshear bond strength to dentin was tested and the morphology of adhesive interaction was analyzed microscopically. In the third part of this thesis, the effect of HAP-based inserts (standardized inlays) on polymerization shrinkage and displacements of restorations was investigated using the digital image correlation method based on two cameras for obtaining three-dimensional information. The restorations were prepared by cementing HAP inserts in standardized dentin discs with a universal or a flowable composite, or a resin-modified glass-ionomer cement. Bond strength to the aforementioned materials was also tested. HAP fillers were comparable to conventional glass fillers in terms of mechanical properties. HAP spheres even improved mechanical properties of experimental composites initially and after storage in Hank‟s balanced salt solution during 4 weeks..., Kalcijum hidroksiapatit (HAP) čini osnovnu mineralnu komponentu čvrstih zubnih tkiva pa kao takav predstavlja poţeljnu komponentu materijala koji izgubljena zubna tkiva treba da nadoknade. U eri estetske stomatologije najzastupljeniji restaurativni materijali su kompoziti adhezivno vezani za tvrda zubna tkiva. Osnovni nedostatak kompozitnih materijala i dalje predstavlja polimerizaciona kontrakcija, koja uzrokuje stvaranje napona u materijalu i dovodi do nastanka mikropukotine na njihovom spoju sa zubnim tkivima. Cilj ove doktorske disertacije bio je da se ispita uticaj HAP punilaca u kompozitima i adhezivima na njihova mehanička svojstva i vezu sa dentinom, kao i pravljenje i testiranje inserata na bazi HAP-a kao potencijalnih dentinskih zamenika. Testiran je uticaj zamene dela staklenih punilaca jednim od pet oblika HAP punilaca (nanočestičnim, mikročestičnim: sferama sa i bez dopiranja silicijumom i trakama sa i bez dopiranja silicijumom), na stepen konverzije, tvrdoću po Vikersu, savojnu čvrstoću, savojni moduo elastičnosti, kompresivnu čvrstoću i kompresivni moduo elastičnosti eksperimentalnih kompozita, inicijalno i nakon „starenja‟. Optimalan maseni udeo punilaca na bazi HAP-a odreĎen je pilot studijama. Osim toga, dva oblika nanočestičnog HAP-a (u obliku nano-iglica i nano-traka) u udelima 0,5-1,5 mas% su u obliku suspenzije dodavana u komercijalne adhezive, nakon čega je testom makrosmicanja ispitana jačina veze, a skenirajućom elektronskom mikroskopijom morfologija interakcije dobijenih adheziva sa dentinom. U trećem delu studije ispitivan je uticaj primene inserata na bazi HAP-a (standardizovani inleji) na zapreminsku kontrakciju i pomeranje materijala metodom korelacije digitalnih slika sa korišćenjem sistema dve kamere za trodimenzionalno merenje, kod restauracija koje su činili inserti u kombinaciji sa univerzalnim ili tečnim kompozitom, odnosno smolom modifikovanim glas jonomer cementom. TakoĎe je merena jačina veze HAP inserata sa pomenutim materijalima. HAP punioci svojim mehaničkim svojstvima mogu da pariraju najčešće korišćenim staklenim puniocima, pri čemu su HAP sfere pozitivno uticale na mehanička svojstva testiranih materijala, kao inicijalno, tako i nakon „starenja‟ u Henkovom rastvoru tokom 4 nedelje...",
publisher = "Univerzitet u Beogradu, Stomatološki fakultet",
title = "Composites and adhesives with synthetic hydroxyapatite fillers and hydroxyapatite inserts : evaluation of mechanical properties and the quality of the adhesive bond, Kompoziti i adhezivi sa sintetskim hidroksiapatitnim puniocima i hidroksiapatitni inserti : ispitivanje mehaničkih svojstava i kvaliteta adhezivne veze",
url = "https://hdl.handle.net/21.15107/rcub_nardus_5122"
}
Ležaja, M.. (2015). Composites and adhesives with synthetic hydroxyapatite fillers and hydroxyapatite inserts : evaluation of mechanical properties and the quality of the adhesive bond. 
Univerzitet u Beogradu, Stomatološki fakultet..
https://hdl.handle.net/21.15107/rcub_nardus_5122
Ležaja M. Composites and adhesives with synthetic hydroxyapatite fillers and hydroxyapatite inserts : evaluation of mechanical properties and the quality of the adhesive bond. 2015;.
https://hdl.handle.net/21.15107/rcub_nardus_5122 .
Ležaja, Maja, "Composites and adhesives with synthetic hydroxyapatite fillers and hydroxyapatite inserts : evaluation of mechanical properties and the quality of the adhesive bond" (2015),
https://hdl.handle.net/21.15107/rcub_nardus_5122 .

Effect of hydroxyapatite spheres, whiskers, and nanoparticles on mechanical properties of a model BisGMA/TEGDMA composite initially and after storage

Ležaja, Maja; Veljović, Đorđe; Jokić, Bojan; Cvijović-Alagić, Ivana; Zrilić, Milorad; Miletić, Vesna

(Wiley-Blackwell, Hoboken, 2013)

TY  - JOUR
AU  - Ležaja, Maja
AU  - Veljović, Đorđe
AU  - Jokić, Bojan
AU  - Cvijović-Alagić, Ivana
AU  - Zrilić, Milorad
AU  - Miletić, Vesna
PY  - 2013
UR  - https://smile.stomf.bg.ac.rs/handle/123456789/1848
AB  - This study investigated the effect of shape, size, and surface modification of hydroxyapatite (HAP) fillers on the degree of conversion (DC) and mechanical properties of a model BisGMA/TEGDMA composite initially and after 4 weeks of storage. Ten percent of conventional glass fillers were replaced by HAP spheres (Sph), silicon-doped spheres (Sph(Si)), whiskers (Wh), silicon-doped whiskers (Wh(Si)), and nanosized HAP particles (Nano). Spheres were specifically structured agglomerates consisting of a central void and radially orientated primary particles, whereas whiskers were compact monocrystals. DC, Vickers hardness (HV), flexural strength (Fs), flexural modulus (Ef), compressive strength (Cs), and compressive modulus (Ec) were tested. There were no significant differences in the DC between all tested groups. HV decreased by 5.4-17% with the addition of HAP, while Fs increased by 13.9-29% except in Nano group (decrease by 13%). After storage, Sph and Sph(Si) groups showed similar HV, Ef, Cs and Ec and higher Fs than the control. The fracture mode of HAP spheres was through the central void whereas whiskers showed longitudinal delamination, transverse, and mixed fractures. HAP spheres with or without silicon- doping have a potential to be part of the filler content of dental composites.
PB  - Wiley-Blackwell, Hoboken
T2  - Journal of Biomedical Materials Research Part B: Applied Biomaterials
T1  - Effect of hydroxyapatite spheres, whiskers, and nanoparticles on mechanical properties of a model BisGMA/TEGDMA composite initially and after storage
VL  - 101
IS  - 8
SP  - 1469
EP  - 1476
DO  - 10.1002/jbm.b.32967
ER  - 
@article{
author = "Ležaja, Maja and Veljović, Đorđe and Jokić, Bojan and Cvijović-Alagić, Ivana and Zrilić, Milorad and Miletić, Vesna",
year = "2013",
abstract = "This study investigated the effect of shape, size, and surface modification of hydroxyapatite (HAP) fillers on the degree of conversion (DC) and mechanical properties of a model BisGMA/TEGDMA composite initially and after 4 weeks of storage. Ten percent of conventional glass fillers were replaced by HAP spheres (Sph), silicon-doped spheres (Sph(Si)), whiskers (Wh), silicon-doped whiskers (Wh(Si)), and nanosized HAP particles (Nano). Spheres were specifically structured agglomerates consisting of a central void and radially orientated primary particles, whereas whiskers were compact monocrystals. DC, Vickers hardness (HV), flexural strength (Fs), flexural modulus (Ef), compressive strength (Cs), and compressive modulus (Ec) were tested. There were no significant differences in the DC between all tested groups. HV decreased by 5.4-17% with the addition of HAP, while Fs increased by 13.9-29% except in Nano group (decrease by 13%). After storage, Sph and Sph(Si) groups showed similar HV, Ef, Cs and Ec and higher Fs than the control. The fracture mode of HAP spheres was through the central void whereas whiskers showed longitudinal delamination, transverse, and mixed fractures. HAP spheres with or without silicon- doping have a potential to be part of the filler content of dental composites.",
publisher = "Wiley-Blackwell, Hoboken",
journal = "Journal of Biomedical Materials Research Part B: Applied Biomaterials",
title = "Effect of hydroxyapatite spheres, whiskers, and nanoparticles on mechanical properties of a model BisGMA/TEGDMA composite initially and after storage",
volume = "101",
number = "8",
pages = "1469-1476",
doi = "10.1002/jbm.b.32967"
}
Ležaja, M., Veljović, Đ., Jokić, B., Cvijović-Alagić, I., Zrilić, M.,& Miletić, V.. (2013). Effect of hydroxyapatite spheres, whiskers, and nanoparticles on mechanical properties of a model BisGMA/TEGDMA composite initially and after storage. in Journal of Biomedical Materials Research Part B: Applied Biomaterials
Wiley-Blackwell, Hoboken., 101(8), 1469-1476.
https://doi.org/10.1002/jbm.b.32967
Ležaja M, Veljović Đ, Jokić B, Cvijović-Alagić I, Zrilić M, Miletić V. Effect of hydroxyapatite spheres, whiskers, and nanoparticles on mechanical properties of a model BisGMA/TEGDMA composite initially and after storage. in Journal of Biomedical Materials Research Part B: Applied Biomaterials. 2013;101(8):1469-1476.
doi:10.1002/jbm.b.32967 .
Ležaja, Maja, Veljović, Đorđe, Jokić, Bojan, Cvijović-Alagić, Ivana, Zrilić, Milorad, Miletić, Vesna, "Effect of hydroxyapatite spheres, whiskers, and nanoparticles on mechanical properties of a model BisGMA/TEGDMA composite initially and after storage" in Journal of Biomedical Materials Research Part B: Applied Biomaterials, 101, no. 8 (2013):1469-1476,
https://doi.org/10.1002/jbm.b.32967 . .
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Temperature Changes in Silorane-, Ormocer-, and Dimethacrylate-Based Composites and Pulp Chamber Roof during Light-Curing

Miletić, Vesna; Ivanović, Vladimir; Dželetović, Bojan; Ležaja, Maja

(Wiley-Blackwell Publishing, Inc, Malden, 2009)

TY  - JOUR
AU  - Miletić, Vesna
AU  - Ivanović, Vladimir
AU  - Dželetović, Bojan
AU  - Ležaja, Maja
PY  - 2009
UR  - https://smile.stomf.bg.ac.rs/handle/123456789/1511
AB  - Light-curing of resin-based composites (RBCs) is associated with temperature increase in the pulp chamber, which may have a detrimental effect on the vital pulp. The purpose of the study was to evaluate temperature changes of silorane-, ormocer-, and dimethacrylate-based RBCs at the bottom surface of the RBC and in the pulp chamber roof dentin (PCRD) during curing. In part A, temperatures were measured for Filtek LS (3M ESPE, St. Paul, MN, USA), Admira (Voco GmbH, Cuxhaven, Germany), and Herculite XRV (Kerr Corp., Orange, CA, USA) with a high-power light-emitting diode (LED) unit by placing thermocouples in contact with the bottom surface of the material in standardized acrylic molds. In part B, temperature changes in PCRD were measured in extracted molars during light-curing of adhesives and RBCs in 2-mm-deep cavities with a remaining dentin thickness (RDT) of 1 mm. Filtek LS showed a different temperature curve compared with Admira and Herculite XRV. Significantly higher temperatures were recorded for Filtek LS (p  lt  0.001) than for Admira and Herculite XRV in acrylic molds. Temperature rises recorded in PCRD for adhesives and RBCs were between 4.1 and 6.4 degrees C. No significant differences in PCRD temperatures were found between the three groups during adhesive curing and RBC curing (p > 0.05). Filtek LS showed a different heat-generation pattern from and significantly higher temperatures than Admira and Herculite XRV when the materials were tested in acrylic molds. Similar temperatures were recorded in the PCRD during curing of adhesives and RBCs. Although a substantial temperature rise in the bulk material occurred during light-curing of the three resin-based composites, a remaining dentin thickness of 1 mm caused a significant reduction in pulp chamber roof dentin temperatures. Temperatures measured in the pulp chamber roof dentin corresponding to the zone occupied by the postmitotic odontoblast layer were not statistically different for the three types of resin-based composites.
PB  - Wiley-Blackwell Publishing, Inc, Malden
T2  - Journal of Esthetic & Restorative Dentistry
T1  - Temperature Changes in Silorane-, Ormocer-, and Dimethacrylate-Based Composites and Pulp Chamber Roof during Light-Curing
VL  - 21
IS  - 2
SP  - 122
EP  - 131
DO  - 10.1111/j.1708-8240.2009.00244.x
ER  - 
@article{
author = "Miletić, Vesna and Ivanović, Vladimir and Dželetović, Bojan and Ležaja, Maja",
year = "2009",
abstract = "Light-curing of resin-based composites (RBCs) is associated with temperature increase in the pulp chamber, which may have a detrimental effect on the vital pulp. The purpose of the study was to evaluate temperature changes of silorane-, ormocer-, and dimethacrylate-based RBCs at the bottom surface of the RBC and in the pulp chamber roof dentin (PCRD) during curing. In part A, temperatures were measured for Filtek LS (3M ESPE, St. Paul, MN, USA), Admira (Voco GmbH, Cuxhaven, Germany), and Herculite XRV (Kerr Corp., Orange, CA, USA) with a high-power light-emitting diode (LED) unit by placing thermocouples in contact with the bottom surface of the material in standardized acrylic molds. In part B, temperature changes in PCRD were measured in extracted molars during light-curing of adhesives and RBCs in 2-mm-deep cavities with a remaining dentin thickness (RDT) of 1 mm. Filtek LS showed a different temperature curve compared with Admira and Herculite XRV. Significantly higher temperatures were recorded for Filtek LS (p  lt  0.001) than for Admira and Herculite XRV in acrylic molds. Temperature rises recorded in PCRD for adhesives and RBCs were between 4.1 and 6.4 degrees C. No significant differences in PCRD temperatures were found between the three groups during adhesive curing and RBC curing (p > 0.05). Filtek LS showed a different heat-generation pattern from and significantly higher temperatures than Admira and Herculite XRV when the materials were tested in acrylic molds. Similar temperatures were recorded in the PCRD during curing of adhesives and RBCs. Although a substantial temperature rise in the bulk material occurred during light-curing of the three resin-based composites, a remaining dentin thickness of 1 mm caused a significant reduction in pulp chamber roof dentin temperatures. Temperatures measured in the pulp chamber roof dentin corresponding to the zone occupied by the postmitotic odontoblast layer were not statistically different for the three types of resin-based composites.",
publisher = "Wiley-Blackwell Publishing, Inc, Malden",
journal = "Journal of Esthetic & Restorative Dentistry",
title = "Temperature Changes in Silorane-, Ormocer-, and Dimethacrylate-Based Composites and Pulp Chamber Roof during Light-Curing",
volume = "21",
number = "2",
pages = "122-131",
doi = "10.1111/j.1708-8240.2009.00244.x"
}
Miletić, V., Ivanović, V., Dželetović, B.,& Ležaja, M.. (2009). Temperature Changes in Silorane-, Ormocer-, and Dimethacrylate-Based Composites and Pulp Chamber Roof during Light-Curing. in Journal of Esthetic & Restorative Dentistry
Wiley-Blackwell Publishing, Inc, Malden., 21(2), 122-131.
https://doi.org/10.1111/j.1708-8240.2009.00244.x
Miletić V, Ivanović V, Dželetović B, Ležaja M. Temperature Changes in Silorane-, Ormocer-, and Dimethacrylate-Based Composites and Pulp Chamber Roof during Light-Curing. in Journal of Esthetic & Restorative Dentistry. 2009;21(2):122-131.
doi:10.1111/j.1708-8240.2009.00244.x .
Miletić, Vesna, Ivanović, Vladimir, Dželetović, Bojan, Ležaja, Maja, "Temperature Changes in Silorane-, Ormocer-, and Dimethacrylate-Based Composites and Pulp Chamber Roof during Light-Curing" in Journal of Esthetic & Restorative Dentistry, 21, no. 2 (2009):122-131,
https://doi.org/10.1111/j.1708-8240.2009.00244.x . .
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