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Effect of hydrogen peroxide topical applications on enamel and composite resin surfaces
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continuous low irradiance (CL) with 150 mW/cm2 for 160 s, soft-start (SS) with 150 mW/cm2 for 5 s + 600 mW/cm2 for 39 s, and pulse-delay (PD) with 150 mW/cm2 for 5 s + 3 min in dark room + 600 mW/cm2 for 39 s modes. Initial Knoop hardness (KHN) measurements were performed 24 h after dry storage at 37 ◦ C. The specimens of each resin–composite were stored in absolute ethanol (100%), for 24 h at room temperature, and KHN was determined anew. Percentages of hardness decrease were analyzed by two-way ANOVA followed by pairwise Tukey’s test (p = 0.05). Results: No statistically significant differences were observed between the different photoactivation modes. After storage in 100% ethanol solution, KHN was decreased in all cases but no significant differences were detected between photo-activation modes (Filtek Z350: C = 27.8%; CL = 26.1%; SS = 31.3%; PD = 30.5%; Filtek P90: C = 25.1%; CL = 32.8%; SS = 23%; PD = 24.5%) regardless of the resin-composite tested. Conclusions: The photoactivation mode and resin composite formulation did not influence the crosslinking density of the resin composites evaluated. doi:10.1016/j.dental.2010.08.058 51 Influence of energy dose on the hardness, depth of polymerization and internal gap formation of methacrylate- and silorane-based restorations D’alpino 1 ,
Hipolito 1 ,
Bechtold 1 ,
P.H.P. V.D. J. R.C.B. Alonso 1 , F.P. Rodrigues 1 , N. Silikas 2
P.J.
Santos 1 ,
1
Bandeirante University of São Paulo, Brazil 2 University of Manchester, UK
Objectives: To investigate the influence of energy dose on the Knoop hardness, polymerization depth, and internal gap formation of silorane-based and methacrylate-based composite in Class II restorations. Materials and methods: Class II cavities were prepared on mesial and distal surfaces of extracted third molars, and randomly distributed in 4 groups (n = 10) according to the restorative systems (1. Filtek P60: methacrylate-based composite + Adper Easy One; 2. Filtek P90: silorane-based composite + P90 System Adhesive) and the energy dose (20J: 1000 mW/cm2 × 20 s; and 40 J: 1000 mW/cm2 × 40 s). Composites were applied in two increments and then photoactivated using an LED curing-light device (Bluephase, Ivoclar Vivadent, Liechtenstein). After 24 h, restorations were mesio-distally sectioned. Knoop-hardness was evaluated across the transversal section of the fillings (1–4 mm below the restoration surface) using a load of 50 g for 5 s. Samples were then air-dried and a drop of 1% acid red propylene glycol solution was applied to the internal margins for 20 s. Samples were then water-rinsed, air-dried and digitally-imaged recorded. The internal gap (%) was calculated as the ratio between the stained margins and the total length of the internal margin. Two-way (for internal gap) and three-way (for depth) ANOVA and Tukey’s test were then performed (˛ = 0.05). Results: Regarding the internal gap formation, no significance was seen among experimental groups when
considering both the restorative systems and energy doses. Most specimens showed perfect sealing of internal margins. Silorane-based composite presented significantly lower hardness values than methacrylate-based composite (p < 0.05) for all depths and doses. Higher energy dose (40 J) produced higher KHN only for Filtek P90, while Filtek P60 was not affected by the energy dose applied. KHN was not also affected by the depth, presenting similar mean values. Results are presented in the table as follows:
Hardness
20 J
40 J
Internal gap (%)
20 J
40 J
Filtek P60 Filtek P90
97.1aA 59.3bB
95.6aA 61.7bA
Filtek P60 Filtek P90
4.4aA 5.2aA
8.8aA 8.5aA
Different small letters in column and capital letters in row: significant (p < 0.05).
Conclusions: Internal gap formation is neither affected by the restorative system nor by the energy dose applied. Hardness values are determined by the type of composite and energy dose. The methacrylate-based composite is harder than the silorane-based composite. Higher energy dose produces increased hardness values only for the silorane-based composite. doi:10.1016/j.dental.2010.08.059 52 Effect of hydrogen peroxide topical applications on enamel and composite resin surfaces M. D’Amario 1,∗ , G. Turco 2 , M. Castronovo 1 , M. Ciribe 1 , R. Di Lenarda 2 , M. Giannoni 1 , M. Baldi 1 1 2
University of L’Aquila, Italy University of Trieste, Italy
Objectives: The objectives of the present study were to analyze the morphology and the superficial roughness of enamel and composite resin restorations after three different bleaching regimens. Materials and methods: Enamel specimens were obtained from buccal surfaces of 21 human incisors. Two specimens were obtained for each tooth. Half part of each tooth was maintained in distilled water and served as control; the other part was treated with one of three professional bleaching agents: 38% hydrogen peroxide (Opalescence Boost; Ultradent Products, Inc.), 35% hydrogen peroxide (Whiteness HP Maxx; FGM Produtos Odontológicos Ltda), light-activated 25% hydrogen peroxide (Zoom 2; Discus Dental Inc.). The same bleaching protocols were applied on standardized composite resin (CeramX mono; Dentsply De Trey) surfaces. Composite specimens were divided in four subgroups (n = 7), according to surface treatment (distilled water was used for control group). Two enamel and composite specimens for each group were submitted to a qualitative scanning electron microscopy (SEM) analysis. Remaining specimens were measured for roughness using a 3D optical profilometer (Talysurf CLI 1000; Taylor Hobson). Data were statistically analyzed.
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d e n t a l m a t e r i a l s 2 6 S ( 2 0 1 0 ) e1–e84
Results: A preliminary profilometric analysis of the enamel and composite surfaces after bleaching protocols showed no significant differences in surface roughness parameters (p > 0.05) compared with those at baseline. Results of the correlated SEM analysis showed no relevant alteration on the enamel surfaces. However, some significant changes of composite surface morphology were SEM observed at high resolution (×1000 and ×3000) after conditioning treatments, suggesting a predominance of depressions after each of the three bleaching procedures. Conclusions: Although SEM analysis seems to suggest that professional bleaching procedures may adversely affect the microscopic surface texture of composites, the profilometric results showed that the tested bleaching regimens do not alter enamel and composite surface roughness.
p < 0.001); 40 s vs. 20 s (most comp. p < 0.05); increased thickness led to decreased hardness only on bottom surfaces (most comp. p < 0.005); hardness increased at t1 (all comp. t0 vs. t1, p < 0.05), then decreased at t2 (all comp. t1 vs. t2, p < 0.05); however, the t2 values remained greater than those at t0 (most comp. t0 vs. t2, p < 0.05).
Conclusions: SDR showed low hardness values, which decreased after 24 h storage in artificial saliva; further investigations are required before its clinical use. doi:10.1016/j.dental.2010.08.061 54 Evaluation of surface roughness and filler characteristics of restorative composites
doi:10.1016/j.dental.2010.08.060
M. Di Francescantonio 1,∗ , R. Giannini 1
53
1 2
Microhardness of a new flowable composite liner for posterior restorations M. de Biasi, R.M. Calvi, D. Sossi, M. Maglione, D. Angerame University of Trieste, Trieste, Italy Objectives: A recently introduced flowable composite liner for I and II class restorations is supposed to be efficiently polymerized up to 4 mm thick increments according to manufacturer’s indications. This preliminary study investigated the microhardness of SDR liner in relation to thickness and storage. Materials and methods: Four moulds (thickness: 2, 3, 4, and 5 mm, diameter: 4 mm) were prepared. Ten SDR (Dentsply Caulk) discs for each thickness subgroup (total sample size = 160) were polymerized following 4 different protocols by using halogen (Elipar 2500, 3M ESPE) or LED (BluePhase G2, Ivoclar Vivadent) lamp, for 20 or 40 s. Six indentations per specimen (3 on top and 3 on bottom surface) were performed with a Vickers indenter (VHMT 30, Leica). Three measurement times were considered: t0, immediately after polymerization; t1, after 24 h in dry environment; t2, after further 24 h in artificial saliva. Statistical analysis was performed by nonparametric tests. Results: Data expressed in HV
Halogen
LED
20 s t0 Top Bottom
11.5 9.8
11.4 8.6
11.6 7.4
11.5 5.9
13.0 11.7
12.6 10.9
12.2 9.0
12.9 8.7
t1 Top Bottom
20.5 20.2
20.6 19.8
20.5 18.6
20.7 17.2
20.9 20.8
20.9 18.8
21.0 16.8
21.0 14.9
t2 Top Bottom
12.6 12.4
12.7 12.0
12.7 11.2
12.7 8.4
13.3 13.2
13.3 12.3
13.3 12.0
13.2 11.0
40 s t0 Top Bottom
12.7 11.2
11.9 10.2
11.9 9.0
12.2 7.8
14.9 14.0
13.6 12.9
13.5 10.0
13.1 8.9
t1 Top Bottom
20.9 20.8
20.9 18.9
20.8 17.8
20.9 16.9
21.7 21.5
21.7 21.1
21.5 19.1
21.7 17.6
t2 Top Bottom
14.5 14.4
14.6 14.1
14.6 13.9
14.6 11.2
14.7 14.7
14.7 14.1
14.4 11.7
14.6 11.1
2 mm 3 mm 4 mm 5 mm 2 mm 3 mm 4 mm 5 mm
Differences among groups were found as follows: top vs. bottom surface (most comparisons p < 0.005); LED vs. halogen lamp (most comp.
Pacheco 1 , R.R.
Braga 2 , M.
Piracicaba Dental School, State University of Campinas, Brazil School of Dentistry, University of São Paulo, São Paulo, Brazil
Objectives: The purpose of the present study was to investigate the surface roughness after finishing and polishing and the filler characteristics of four resin-based composites. Materials and methods: Two low shrink composites (Filtek LS, 3M ESPE e Aelite LS, Bisco Inc.), two composites with conventional composition (Heliomolar e Tetric N-Ceram, Ivoclar Vivadent) and finishing and polishing systems of their respective manufacturers (Sof-Lex Disks, 3M ESPE; Finishing Discs Kit, Bisco Inc. e Astropol F, P, AH, Ivoclar-Vivadent) were evaluated. Discs of composites (2 mm high × 15 mm diameter) were prepared (n = 5). Afterwards, they were finished and polished according to the manufacturers’ instructions. The polished surfaces were evaluated using a profilometer (Surfcorder SE 1700, Kosaka Corp.) and the data (Ra/m) were statistically analyzed by ANOVA and Tukey test (p < 0.05). The composite filler particles were observed using scanning electron microscopy (SEM) (JSM 5600LV, Jeol), after removal of the resin matrix by organic solvents (ethanol and acetone). The size, shape, type and other characteristics of fillers were analyzed. Results: Significant differences were found for the surface roughness. Aelite LS (0.28 m) and Tetric N-Ceram (0.25 m) presented the roughest surfaces, following by heliomolar (0.20 m) and Filtek LS (0.15 m), respectively. For the filler characteristics, the materials presented differences in filler contents (e.g. particle size and shape). Conclusions: The results showed that the surface roughness was influenced by the filler characteristics, also by the finishing and polishing manufacturers’ systems. doi:10.1016/j.dental.2010.08.062
d e n t a l m a t e r i a l s 2 6 S ( 2 0 1 0 ) e1–e84
continuous low irradiance (CL) with 150 mW/cm2 for 160 s, soft-start (SS) with 150 mW/cm2 for 5 s + 600 mW/cm2 for 39 s, and pulse-delay (PD) with 150 mW/cm2 for 5 s + 3 min in dark room + 600 mW/cm2 for 39 s modes. Initial Knoop hardness (KHN) measurements were performed 24 h after dry storage at 37 ◦ C. The specimens of each resin–composite were stored in absolute ethanol (100%), for 24 h at room temperature, and KHN was determined anew. Percentages of hardness decrease were analyzed by two-way ANOVA followed by pairwise Tukey’s test (p = 0.05). Results: No statistically significant differences were observed between the different photoactivation modes. After storage in 100% ethanol solution, KHN was decreased in all cases but no significant differences were detected between photo-activation modes (Filtek Z350: C = 27.8%; CL = 26.1%; SS = 31.3%; PD = 30.5%; Filtek P90: C = 25.1%; CL = 32.8%; SS = 23%; PD = 24.5%) regardless of the resin-composite tested. Conclusions: The photoactivation mode and resin composite formulation did not influence the crosslinking density of the resin composites evaluated. doi:10.1016/j.dental.2010.08.058 51 Influence of energy dose on the hardness, depth of polymerization and internal gap formation of methacrylate- and silorane-based restorations D’alpino 1 ,
Hipolito 1 ,
Bechtold 1 ,
P.H.P. V.D. J. R.C.B. Alonso 1 , F.P. Rodrigues 1 , N. Silikas 2
P.J.
Santos 1 ,
1
Bandeirante University of São Paulo, Brazil 2 University of Manchester, UK
Objectives: To investigate the influence of energy dose on the Knoop hardness, polymerization depth, and internal gap formation of silorane-based and methacrylate-based composite in Class II restorations. Materials and methods: Class II cavities were prepared on mesial and distal surfaces of extracted third molars, and randomly distributed in 4 groups (n = 10) according to the restorative systems (1. Filtek P60: methacrylate-based composite + Adper Easy One; 2. Filtek P90: silorane-based composite + P90 System Adhesive) and the energy dose (20J: 1000 mW/cm2 × 20 s; and 40 J: 1000 mW/cm2 × 40 s). Composites were applied in two increments and then photoactivated using an LED curing-light device (Bluephase, Ivoclar Vivadent, Liechtenstein). After 24 h, restorations were mesio-distally sectioned. Knoop-hardness was evaluated across the transversal section of the fillings (1–4 mm below the restoration surface) using a load of 50 g for 5 s. Samples were then air-dried and a drop of 1% acid red propylene glycol solution was applied to the internal margins for 20 s. Samples were then water-rinsed, air-dried and digitally-imaged recorded. The internal gap (%) was calculated as the ratio between the stained margins and the total length of the internal margin. Two-way (for internal gap) and three-way (for depth) ANOVA and Tukey’s test were then performed (˛ = 0.05). Results: Regarding the internal gap formation, no significance was seen among experimental groups when
considering both the restorative systems and energy doses. Most specimens showed perfect sealing of internal margins. Silorane-based composite presented significantly lower hardness values than methacrylate-based composite (p < 0.05) for all depths and doses. Higher energy dose (40 J) produced higher KHN only for Filtek P90, while Filtek P60 was not affected by the energy dose applied. KHN was not also affected by the depth, presenting similar mean values. Results are presented in the table as follows:
Hardness
20 J
40 J
Internal gap (%)
20 J
40 J
Filtek P60 Filtek P90
97.1aA 59.3bB
95.6aA 61.7bA
Filtek P60 Filtek P90
4.4aA 5.2aA
8.8aA 8.5aA
Different small letters in column and capital letters in row: significant (p < 0.05).
Conclusions: Internal gap formation is neither affected by the restorative system nor by the energy dose applied. Hardness values are determined by the type of composite and energy dose. The methacrylate-based composite is harder than the silorane-based composite. Higher energy dose produces increased hardness values only for the silorane-based composite. doi:10.1016/j.dental.2010.08.059 52 Effect of hydrogen peroxide topical applications on enamel and composite resin surfaces M. D’Amario 1,∗ , G. Turco 2 , M. Castronovo 1 , M. Ciribe 1 , R. Di Lenarda 2 , M. Giannoni 1 , M. Baldi 1 1 2
University of L’Aquila, Italy University of Trieste, Italy
Objectives: The objectives of the present study were to analyze the morphology and the superficial roughness of enamel and composite resin restorations after three different bleaching regimens. Materials and methods: Enamel specimens were obtained from buccal surfaces of 21 human incisors. Two specimens were obtained for each tooth. Half part of each tooth was maintained in distilled water and served as control; the other part was treated with one of three professional bleaching agents: 38% hydrogen peroxide (Opalescence Boost; Ultradent Products, Inc.), 35% hydrogen peroxide (Whiteness HP Maxx; FGM Produtos Odontológicos Ltda), light-activated 25% hydrogen peroxide (Zoom 2; Discus Dental Inc.). The same bleaching protocols were applied on standardized composite resin (CeramX mono; Dentsply De Trey) surfaces. Composite specimens were divided in four subgroups (n = 7), according to surface treatment (distilled water was used for control group). Two enamel and composite specimens for each group were submitted to a qualitative scanning electron microscopy (SEM) analysis. Remaining specimens were measured for roughness using a 3D optical profilometer (Talysurf CLI 1000; Taylor Hobson). Data were statistically analyzed.
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d e n t a l m a t e r i a l s 2 6 S ( 2 0 1 0 ) e1–e84
Results: A preliminary profilometric analysis of the enamel and composite surfaces after bleaching protocols showed no significant differences in surface roughness parameters (p > 0.05) compared with those at baseline. Results of the correlated SEM analysis showed no relevant alteration on the enamel surfaces. However, some significant changes of composite surface morphology were SEM observed at high resolution (×1000 and ×3000) after conditioning treatments, suggesting a predominance of depressions after each of the three bleaching procedures. Conclusions: Although SEM analysis seems to suggest that professional bleaching procedures may adversely affect the microscopic surface texture of composites, the profilometric results showed that the tested bleaching regimens do not alter enamel and composite surface roughness.
p < 0.001); 40 s vs. 20 s (most comp. p < 0.05); increased thickness led to decreased hardness only on bottom surfaces (most comp. p < 0.005); hardness increased at t1 (all comp. t0 vs. t1, p < 0.05), then decreased at t2 (all comp. t1 vs. t2, p < 0.05); however, the t2 values remained greater than those at t0 (most comp. t0 vs. t2, p < 0.05).
Conclusions: SDR showed low hardness values, which decreased after 24 h storage in artificial saliva; further investigations are required before its clinical use. doi:10.1016/j.dental.2010.08.061 54 Evaluation of surface roughness and filler characteristics of restorative composites
doi:10.1016/j.dental.2010.08.060
M. Di Francescantonio 1,∗ , R. Giannini 1
53
1 2
Microhardness of a new flowable composite liner for posterior restorations M. de Biasi, R.M. Calvi, D. Sossi, M. Maglione, D. Angerame University of Trieste, Trieste, Italy Objectives: A recently introduced flowable composite liner for I and II class restorations is supposed to be efficiently polymerized up to 4 mm thick increments according to manufacturer’s indications. This preliminary study investigated the microhardness of SDR liner in relation to thickness and storage. Materials and methods: Four moulds (thickness: 2, 3, 4, and 5 mm, diameter: 4 mm) were prepared. Ten SDR (Dentsply Caulk) discs for each thickness subgroup (total sample size = 160) were polymerized following 4 different protocols by using halogen (Elipar 2500, 3M ESPE) or LED (BluePhase G2, Ivoclar Vivadent) lamp, for 20 or 40 s. Six indentations per specimen (3 on top and 3 on bottom surface) were performed with a Vickers indenter (VHMT 30, Leica). Three measurement times were considered: t0, immediately after polymerization; t1, after 24 h in dry environment; t2, after further 24 h in artificial saliva. Statistical analysis was performed by nonparametric tests. Results: Data expressed in HV
Halogen
LED
20 s t0 Top Bottom
11.5 9.8
11.4 8.6
11.6 7.4
11.5 5.9
13.0 11.7
12.6 10.9
12.2 9.0
12.9 8.7
t1 Top Bottom
20.5 20.2
20.6 19.8
20.5 18.6
20.7 17.2
20.9 20.8
20.9 18.8
21.0 16.8
21.0 14.9
t2 Top Bottom
12.6 12.4
12.7 12.0
12.7 11.2
12.7 8.4
13.3 13.2
13.3 12.3
13.3 12.0
13.2 11.0
40 s t0 Top Bottom
12.7 11.2
11.9 10.2
11.9 9.0
12.2 7.8
14.9 14.0
13.6 12.9
13.5 10.0
13.1 8.9
t1 Top Bottom
20.9 20.8
20.9 18.9
20.8 17.8
20.9 16.9
21.7 21.5
21.7 21.1
21.5 19.1
21.7 17.6
t2 Top Bottom
14.5 14.4
14.6 14.1
14.6 13.9
14.6 11.2
14.7 14.7
14.7 14.1
14.4 11.7
14.6 11.1
2 mm 3 mm 4 mm 5 mm 2 mm 3 mm 4 mm 5 mm
Differences among groups were found as follows: top vs. bottom surface (most comparisons p < 0.005); LED vs. halogen lamp (most comp.
Pacheco 1 , R.R.
Braga 2 , M.
Piracicaba Dental School, State University of Campinas, Brazil School of Dentistry, University of São Paulo, São Paulo, Brazil
Objectives: The purpose of the present study was to investigate the surface roughness after finishing and polishing and the filler characteristics of four resin-based composites. Materials and methods: Two low shrink composites (Filtek LS, 3M ESPE e Aelite LS, Bisco Inc.), two composites with conventional composition (Heliomolar e Tetric N-Ceram, Ivoclar Vivadent) and finishing and polishing systems of their respective manufacturers (Sof-Lex Disks, 3M ESPE; Finishing Discs Kit, Bisco Inc. e Astropol F, P, AH, Ivoclar-Vivadent) were evaluated. Discs of composites (2 mm high × 15 mm diameter) were prepared (n = 5). Afterwards, they were finished and polished according to the manufacturers’ instructions. The polished surfaces were evaluated using a profilometer (Surfcorder SE 1700, Kosaka Corp.) and the data (Ra/m) were statistically analyzed by ANOVA and Tukey test (p < 0.05). The composite filler particles were observed using scanning electron microscopy (SEM) (JSM 5600LV, Jeol), after removal of the resin matrix by organic solvents (ethanol and acetone). The size, shape, type and other characteristics of fillers were analyzed. Results: Significant differences were found for the surface roughness. Aelite LS (0.28 m) and Tetric N-Ceram (0.25 m) presented the roughest surfaces, following by heliomolar (0.20 m) and Filtek LS (0.15 m), respectively. For the filler characteristics, the materials presented differences in filler contents (e.g. particle size and shape). Conclusions: The results showed that the surface roughness was influenced by the filler characteristics, also by the finishing and polishing manufacturers’ systems. doi:10.1016/j.dental.2010.08.062