Joe Ontiveros

Many factors influence the quality of shade selection, and isolating how significantly each of these factors influences results is difficult. The purpose of this in vitro study was to compare results of shade matching using handheld lights with or without a polarizing filter with results obtained using a professional viewing booth and to analyze the influence of education and training on shade selection outcome. A total of 96 third-year dental students (evaluators) were randomly separated into 4 groups. Each group was assigned 1 of 2 handheld shade-matching devices (lights) with or without a polarizing filter. Each group performed a shade matching exercise using the handheld light or a professional viewing booth. The exercise consisted of matching shade tabs placed in a typodont to a commercial shade guide. Each group repeated this procedure 4 times over a 9-week period. A lecture on shade matching was presented at the fifth week of the study, between "before" and "af...

Fractures of endodontically treated teeth have been attributed to weakened tooth structure caused by root canal enlargement and post preparation. The purpose of this in vitro study was to evaluate the fracture resistance of roots filled with either gutta percha, composite resin (LuxaCore Dual), or calcium silicate-based cement (Biodentine). One hundred twenty freshly extracted, human, permanent maxillary anterior teeth were sorted by type and assigned to 1 of 4 groups (n=30). The teeth in group NT were not endodontically treated and served as the control. The teeth in groups GP, LC, and, BD were accessed and instrumented to size 40/06. In group GP, the root canals were completely filled with gutta percha. In groups LC and BD, only the apical 5-mm portion of the root canals was filled with gutta percha, and the remaining portion of the root canals was filled with (LuxaCore Dual) in group LC and with (Biodentine) in group BD. Fracture resistance (kN) was assessed at the middle portion of each root, using a 3-point bending test with a universal testing machine exerting a compressive load on a loading pin at a crosshead speed of 0.5 mm/min until fracture occurred. One-way ANOVA was used to compare the mean root fracture resistance among the 4 groups (α=.05). The mean ± SD fracture loads were 2.13 ±0.53 kN for group NT, 1.97 ± 0.60 kN for group GP, 2.18 ±0.71 kN for group LC, and 2.22 ±0.54 kN for group BD. No statistically significant differences were found among the 4 groups (P>.05). The roots of endodontically treated maxillary anterior permanent incisors filled with gutta percha, Biodentine, or LuxaCore Dual had resistance to fracture similar to that of teeth that were not endodontically treated.

The purpose of this study was to determine if crimping the lingual aspect of commercially available, preveneered, anterior stainless steel primary crowns affects the fracture resistance of the veneer facings. Twenty-six anterior NuSmile crowns (size A1) were divided into 2 groups: group 1 served as the control, and group 2 was manually crimped evenly on the lingual cervical portion. All crowns were cemented onto a screw-mounted resin core duplicated from a manually prepared Kilgore tooth and tested under compression. Recorded were fracture resistance, percent of veneer facing loss, and fracture to the gingival margin. Differences between the control and experimental groups were analyzed by independent t test and chi-square (alpha=0.05). The mean shear force required to fracture the veneers of the noncrimped crowns was 510.11 N (+/-79.66 SD), and 511.02 N (+/-62.37) for the crimped crowns. The mean percentage of veneer facing removed in the noncrimped crowns was 33% (+/-12.18), and 43% (+/-14.30) in the crimped crowns. No significant difference in shear strengths (P=.970) and in percentage of veneer loss (P=.063) was shown between crimped and noncrimped crowns. A mean of 8% of the noncrimped crowns and 23% of the crimped crowns had veneers fracturing to the gingival margin. The chi-square test showed no significant difference (P=.297). The veneer resistance to fracture for the crimped crowns was comparable to noncrimped crowns. The crimped crowns, however, were associated with greater veneer surface area loss.

A method for obtaining more predictable and accurate final impressions with polyvinylsiloxane impression materials in conjunction with stock trays is proposed and tested. Heavy impression material is used in advance for construction of a modified custom tray, while extra-light material is used for obtaining a more accurate final impression.

Objective: To evaluate the accelerated aging effects on color of different composite resins. Method: Shades were selected from two flowable composites, A1, A3, and White (WH), Filtek Supreme Ultra Flowable/3M ESPE (FSU); A1, A3 and Bleach (BL), Tetric EvoFlow/Ivoclar Vivadent (TEF), and A1, A3, and B1 micro-hybrid control (Filtek Z250/3M ESPE). Disc shaped specimens (10 mm X 2 mm, n=60) were polymerized using a halogen curing light (Demetron 501, Kerr/Demetron) for 40 seconds. Specimens were finished using 400-grit SiC paper and polished with a one-step polisher (PoGo, Dentsply/Caulk) for 40 seconds. Color measurements were taken at baseline (after 24 hour-storage in distilled water at 37°C) using a spectrophometer (Color-Eye 7000, GretagMacbeth) and after exposure to accelerated aging (150 kJ/m2) in a Weather-ometer (Ci35A, Atlas). Means and standard deviations were determined. The data were analyzed by analysis of variance. Fisher's PLSD intervals at a 0.05 level of significan...

ABSTRACT Objective: to evaluate the effectiveness and color rebound effect of a 22% carbamide peroxide (CP) at-home whitening system. Methods: A total of 21 subjects were recruited for an at-home tooth whitening clinical study. Subjects were treated overnight for 2 weeks with 22% CP (Venus White, Heraeus Kulzer). Visual color measurement was performed by three color normal evaluators using the Vita Classical (VC) and the 3D Bleachedguide (BG). Instrumental color measurements were performed using an intraoral spectrophotometer (Vita Easyshade Compact). Color measurements were taken on a canine and central incisor at baseline, 2, 3, and 4 weeks. Wilcoxon matched-pair signed-rank test for group comparisons and Bonferroni correction was used to adjust for multiple testing at the 0.05 level of significance. Results: Means (sd) for visual and instrumental whitening-dependent color changes are listed in the table; SGU=shade guide units, DE= total color change 2 weeks minus baseline 3 weeks minus baseline 4 weeks minus baseline Incisor Canine Incisor Canine Incisor Canine SGU(BG) 3.9(1.7) 5.8(2.1) 3.7(1.7) 5.6(2.3) 3.7(1.3) 5.4(2.2) SGU(VC) 5.2(2.8) 8.4(3.5) 4.9(2.4) 8.0(3.5) 4.8(2.5) 8.0(3.5) DE*(ES) 7.0(2.9) 10.2(4.7) 7.1(2.5) 9.1(4.8) 6.7(2.7) 9.9(4.2) For visual shade evaluation with VC and BG, there was a statistically significant decrease in SGU from baseline and each subsequent week among all measurements, p<0.001. For instrumental measurements, there was no difference from week 2 to week 3 for canines and generally no difference between week 3 and week 4 in all parameters for incisors. Conclusions: Visual and instrumental measurements evaluation showed clinical whitening-dependent rebound occurred 1 week post bleaching. In general, color stabilized at 2 weeks post bleaching.

... Methods: Disc specimens (6 x 3 mm) of resin ionomer (RelyX/3M ESPE), white copper cement (Doc's Best/Cooley & Cooley) and composite resin coated with and cured, dental adhesive (Clearfil Protect Bond/ Kuraray) were fabricated.. ...

... Methods: 6x3 mm disc specimens of resin ionomer (RelyX/3M ESPE), white copper cement (Doc's Best/Cooley & Cooley) and composite resin coated with an dental adhesive (Clearfil Protect Bond/ Kuraray) were fabricated, and cured,. ...

... 10.7 (1.7). 1.9 (0.3). Silux Plus. UO. 69 (8). ... This study was supported by Dentsply/Caulk and Ultradent. Seq #187 - Polymer Materials: Characteristics; Mechanical and Physical Properties 11:00 AM-12:15 PM, Friday, 8 March 2002 San Diego Convention Center Exhibit Hall C. ...

... Nomoto, R., McCabe, JF, Hirano, S. (2004) Comparison of halogen, plasma and LED curing units. Oper Dent, 29(3): 287-94. KoBSON. ... Soh, MS, Yap, AUJ, Yu, T., Shen, ZX (2004) Analysis of the degree of conversion of LED and halogen lights using micro-Raman spectroscopy. ...

ABSTRACT Objectives: To perform evaluation instrumental color adjustment potential (CAPI) and visual color adjustment potential (CAPV) of beveled resin composites. Materials and Methods: Single composite specimens (S): Disc-shaped specimens of 8 test shades and the control shade (n=5/shade) were made. Test shades were A2 and B1 of Estelite Omega (EO, Tokuyama), Esthet X HD (EX, Dentsply), Filtek Supreme Plus (FS, 3M ESPE) and Renamel Microfil (RM, Cosmedent); Control shade: A1 of Venus Diamond (Heraeus). Dual specimens (D): outer ring with inner space of D=4 mm, 2-mm thick, with 45 1-mm bevel, n=5/shade) were made of the control shade; inner ring holes were filled with test shades. Spectroradiometer and viewing booth (D65) were used for color evaluations, expressed in ΔE* and visual ratings (VR, from 0=perfect match to 4=poor match), respectively. CAPi and CAPV between test shades [with its center in the middle of the specimen (0) and 2mm from the center (2)], and control shades were calculated as follows: CAPI=1-(ΔE*D/ΔE*S) and CAPV=1-(VRD/VRS) Results: CAPI and CAPV at 0 and 2 are given in the table: B1/EO B1/EX B1/FS B1/RM A2/EO A2/EX A2/FS A2/RM CAPI,D0-S0 0.10(0.07) 0.05(0.05) 0.03(0.06) 0.10(0.07) 0.14(0.07) 0.30(0.06) 0.06(0.17) 0.15(0.16) CAPI,D2-S0 0.64(0.13) -0.16(0.08) 0.16(0.06) 0.07(0.09) 0.47(0.08) 0.69(0.17) 0.48(0.13) 0.42(0.25) CAPV,D0-S0 0.73(0.15) 0.02(0.19) 0.77(0.15) 0.06(0.10) 0.18(0.17) 0.63(0.07) 0.60(0.19) 0.60(0.05) CAPV,D2-S0 0.93(0.15) 0.19(0.22) 0.87(0.18) 0.21(0.08) 0.24(0.12) 0.73(0.28) 0.87(0.18) 0.89(0.07) Each factor (Shade, Brand and Distance from center) was found to be statistically significant (P≤0.001), either alone or in interaction, for each of CAPi and CAPV. Conclusion: Color Adjustment Potential was material and shade dependent. It increased from center towards the margins. Overall CAP was as follows FS (0.48)>EO (0.43)>EX (0.31)=RM(0.31). CAPI: EO(0.34)>EX(0.22)>RM(0.19)>FS (0.18); CAPV: FS(0.78)>EO(0.52)>RM(0.44)>EX(0.39). Acknowledgement: Supported in part by Tokuyama Dental Corp.

ABSTRACTPurpose:: This study was performed to evaluate the influence of accelerated aging on the color and translucency parameter (TP) of bleaching-shade resin composites.This study was performed to evaluate the influence of accelerated aging on the color and translucency parameter (TP) of bleaching-shade resin composites.Materials and Methods: Thirty-three bleaching shades and two control conventional shades of microhybrid (MH) and microfill (MF) resin composite specimens (n = 5) were aged in an accelerated aging chamber set to standard CAM 180 cycles. One side of each specimen was evaluated for surface color and TP changes compared with baseline in increments of 150 kJ/m2 for intervals up to 450 kJ/m2 using a spectrophotometer. A ΔE* 3.7 was considered to be a poor match, and the total TP range was divided into three equal parts representing low, medium, and high translucency. Data were analyzed with analysis of variance.Thirty-three bleaching shades and two control conventional shades of microhybrid (MH) and microfill (MF) resin composite specimens (n = 5) were aged in an accelerated aging chamber set to standard CAM 180 cycles. One side of each specimen was evaluated for surface color and TP changes compared with baseline in increments of 150 kJ/m2 for intervals up to 450 kJ/m2 using a spectrophotometer. A ΔE* 3.7 was considered to be a poor match, and the total TP range was divided into three equal parts representing low, medium, and high translucency. Data were analyzed with analysis of variance.Results: Compared to the baseline, ΔL*, Δa*, Δb*, and ΔE* ranges at 450 kJ/m2 were -0.8 to 5.0, -0.6 to 1.2, -8.3 to 0.0, and 0.7 to 8.6 for MH and 0.2 to 1.3, 0.1 to 1.3, -2.5 to 1.1, and 1.7 to 2.7 for MF composites. Scheffé's S intervals (p < =.05) for comparisons of ΔL*, Δa*, Δb*, and ΔE* values of MH composites between baseline and 450 kJ/m2 were 1.6, 0.6, 1.7, and 1.5, respectively. Corresponding Tukey-Kramer intervals for MF composites were 0.7, 0.3, 0.6, and 0.6, respectively. TP values at baseline ranged from 0.9 to 4.3 for MH and from 1.4 to 2.2 for MF composites, whereas ΔTP for baseline minus 450 kJ/m2 ranged from -1.1 to 1.7 for MH and from -0.1 to 0.3 for MF composites. Scheffé's S interval (p < =.05) for comparisons of ΔTP values of MH composites for baseline minus 450 kJ/m2 was 1.0. Corresponding Tukey-Kramer interval for MF composites was 0.4.Conclusions: Aging-dependent color changes at 450 kJ/m2 were above the limit that indicated a poor match for 18/26 MH, while corresponding values for microfills were within acceptable range. Accelerated aging generally caused decreases in L* (specimens became darker) and a* values (specimens became redder), while b* values increased (specimens became more chromatic) for both MH and MF composites. TP was relatively stable during aging for both MH and MF composites.Compared to the baseline, ΔL*, Δa*, Δb*, and ΔE* ranges at 450 kJ/m2 were -0.8 to 5.0, -0.6 to 1.2, -8.3 to 0.0, and 0.7 to 8.6 for MH and 0.2 to 1.3, 0.1 to 1.3, -2.5 to 1.1, and 1.7 to 2.7 for MF composites. Scheffé's S intervals (p < =.05) for comparisons of ΔL*, Δa*, Δb*, and ΔE* values of MH composites between baseline and 450 kJ/m2 were 1.6, 0.6, 1.7, and 1.5, respectively. Corresponding Tukey-Kramer intervals for MF composites were 0.7, 0.3, 0.6, and 0.6, respectively. TP values at baseline ranged from 0.9 to 4.3 for MH and from 1.4 to 2.2 for MF composites, whereas ΔTP for baseline minus 450 kJ/m2 ranged from -1.1 to 1.7 for MH and from -0.1 to 0.3 for MF composites. Scheffé's S interval (p < =.05) for comparisons of ΔTP values of MH composites for baseline minus 450 kJ/m2 was 1.0. Corresponding Tukey-Kramer interval for MF composites was 0.4.Conclusions: Aging-dependent color changes at 450 kJ/m2 were above the limit that indicated a poor match for 18/26 MH, while corresponding values for microfills were within acceptable range. Accelerated aging generally caused decreases in L* (specimens became darker) and a* values (specimens became redder), while b* values increased (specimens became more chromatic) for both MH and MF composites. TP was relatively stable during aging for both MH and MF composites.