Operative Dentistry[JOURNAL]
Sun
200 papers
Errata.
Oper Dent · 2024 Jan · PMID 38180463 · Publisher ↗
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Tooth Splinting: Implementing a 3D-printed Guide with Pre-defined Composite Resin Reservoirs: A Digital Workflow.
Ntovas P, Gogolas N, Gogolas G … +2 more , Mougiou E, Papazoglou E
Oper Dent · 2024 Jan · PMID 38058017 · Publisher ↗
The integration of digital technologies in dentistry has led to the development of various techniques to facilitate tooth splinting. In the present digital workflow, the advantages of the virtual treatment plan were comb...
The integration of digital technologies in dentistry has led to the development of various techniques to facilitate tooth splinting. In the present digital workflow, the advantages of the virtual treatment plan were combined with the versatility of the commercially available tooth splinting materials. An intraoral scanner was utilized to digitize both arches along with the patient's occlusion, eliminating the need for models from physical impressions. A template based on the virtual design of the splint was 3D-printed and served as a guide to individualize a twisted wire. The bent wire was transferred and bonded, using a 3D-printed template with pre-defined reservoirs for the composite resin. Digital technology has been implemented for tooth splinting, by fabricating a splint after its virtual design. However, the digital fabrication of the metal splints is available for limited splinting materials and the service is only provided by specific centers around the world.
Fracture Resistance of Chairside CAD/CAM Lithium Disilicate-reinforced Ceramic Occlusal Veneers With and Without Margin and Full Coverage Crowns.
Jurado CA, Lee D, Ramirez P … +2 more , Cortes-Treviño DA, Tsujimoto A
Oper Dent · 2024 Jan · PMID 38058016 · Publisher ↗
OBJECTIVE: The aim of this investigation was to compare the fracture resistance of chairside computer-aided design and computer-aided manufacturing (CAD/CAM) lithium disilicate-reinforced ceramic occlusal veneers with an...
OBJECTIVE: The aim of this investigation was to compare the fracture resistance of chairside computer-aided design and computer-aided manufacturing (CAD/CAM) lithium disilicate-reinforced ceramic occlusal veneers with and without margin and traditional full coverage premolar crowns. METHODS AND MATERIALS: A total of 60 chairside CAD/CAM lithium disilicate-reinforced ceramic (Amber Mill, Hass Bio) restorations were designed and fabricated with a chairside CAD/CAM system (CEREC Dentsply Sirona). The restorations were divided into three groups (n=20): 1) occlusal veneer with 1.0-mm uniform occlusal thickness and with chamfer margin; 2) occlusal veneer with 1.0-mm uniform occlusal thickness and without margin; and 3) full coverage crown with uniform occlusal thickness and gingival margin. Occlusal veneers and crowns were cemented with dual cured resin luting cement (Multilink, Ivoclar Vivadent) to printed resin dies, load cycled (5 million load cycles at 1 Hz with 275 N force), and then loaded until fracture. Load at break (LB) and peak load (PL) until fracture were recorded. Scanning electron microscope images of the tested restorations on the abutments were obtained. RESULTS: Fracture strengths were different depending on the design of the restoration. There was no significant difference in fracture strength between the two types of occlusal veneer (LB: 1132.45 N; PL: 1143.30 N for veneers with margin; LB: 1149.25 N; PL: 1219.05 N for veneers without margin). Full coverage crowns showed the lowest fracture resistance (LB: 936.26 N, PL: 976.42 N), which was significantly lower than both designs of occlusal veneer. CONCLUSIONS: The fracture resistance of the CAD/CAM lithium disilicate-reinforced ceramic restorations was influenced by the design. Occlusal veneers with and without margin displayed higher fracture resistance than traditional crowns.
Multi-peak Light-emitting Diode Curing Units and Polymerization of 3D-printed Crown and Bridge Resin.
Chung SH, Jiang ES, Lim BS … +2 more , Kim SH, Chang J
Oper Dent · 2024 Jan · PMID 38058011 · Publisher ↗
PURPOSE: This study aimed to evaluate the substitutive and additive efficacy of multi-peak light-emitting diode (LED) curing units for post-curing of a three-dimensional- (3D-) printed crown and bridge resin. METHODS: A...
PURPOSE: This study aimed to evaluate the substitutive and additive efficacy of multi-peak light-emitting diode (LED) curing units for post-curing of a three-dimensional- (3D-) printed crown and bridge resin. METHODS: A total of 792 disc- and 180 bar-shaped specimens were printed with a crown and bridge resin (NextDent C&B MFH) and post-cured using two LED curing units (VALO Cordless and Bluephase N G4) in fast and standard modes. Conventional post-curing (LC-3D Print Box, Group PC) was compared with LED-only curing (Groups V1, V2, B1, and B2) and LED-combined curing (Groups PV1, PV2, PB1, and PB2) in terms of microhardness, flexural strength, degree of conversion (DC), and CIE L*a*b* color and translucency parameters. Cytotoxicity of the resin eluates was evaluated using the WST-1 assay. Temperature increases on the resin surface were measured with infrared thermography. Data were statistically analyzed using ANOVA and Kruskal-Wallis tests (α=0.05). RESULTS: The microhardness and flexural strength in Groups V1, V2, B1, and DC in all LED-only groups were lower than in other groups (p<0.05). Larger color disparities existed between Group PC and all LED-only groups than between Group PC and the others (p<0.05). There was no significant difference in cytotoxicity among the groups. The temperature increase was lowest in Groups V1 and PV1 during light curing (p<0.05). CONCLUSIONS: Post-curing by multi-peak LED curing units was not as effective as the conventional post-curing device. Additional post-curing by LED curing units did not improve the material properties.
The Effect of Water Coolant and Bur Type on Pulp Temperature When Removing Tooth Structure and Restorative Dental Materials.
Mafrici C, Kingston M, Grice R … +1 more , Abbott PV
Oper Dent · 2024 Jan · PMID 38057997 · Publisher ↗
OBJECTIVE: The aim was to compare intrapulp temperature (IPT) changes when flat-fissure diamond burs and pear-shaped tungsten carbide burs were used to cut tooth structure, amalgam, and composite resin with and without w...
OBJECTIVE: The aim was to compare intrapulp temperature (IPT) changes when flat-fissure diamond burs and pear-shaped tungsten carbide burs were used to cut tooth structure, amalgam, and composite resin with and without water coolant. METHODS: Thermocouples were inserted into the pulp chamber of extracted intact mandibular molars. The thermocouples were connected to an electronic thermometer that detects temperature every second to an accuracy of 0.1°C. IPT changes were recorded while using a high-speed handpiece during MOD cavity preparations (n=40), composite resin removal (n=40), and amalgam removal (n=40). A two-way ANOVA was used for each procedure to test for the effect of bur (pear-shaped tungsten carbide vs flat-fissured diamond) and water coolant (on vs off), with significant main effects (α=0.05) further analyzed using Tukey's multiple comparison test. RESULTS: During MOD cavity preparation, water coolant reduced changes in IPT (0.03±0.27°C) compared to no water coolant (1.27±0.29°C) when tungsten carbide burs were used (p<0.05) but not when diamond burs were used. During composite resin removal, tungsten carbide burs had less changes in IPT (0.55±0.18°C) compared to diamond burs (1.66±0.50°C) with no water coolant (p<0.05). Water coolant also reduced changes in IPT (0.09±0.14°C) compared to no water coolant (1.66±0.50°C) when diamond burs were used (p<0.01). Water coolant did not significantly affect IPT when tungsten carbide burs were used. During amalgam removal, tungsten carbide burs had lower changes in IPT (0.56±0.15°C) compared to diamond burs (1.88±0.43°C) with no water coolant (p<0.05). Water coolant also significantly reduced changes in IPT (0.71±0.2°C) compared to no water coolant (1.88±0.43°C) when diamond burs were used (p<0.05) but not when tungsten carbide burs were used. CONCLUSIONS: Water coolant reduced IPT changes when drilling tooth structure with tungsten carbide burs, but not when removing amalgam or composite. Conversely, water coolant reduced IPT changes when drilling with flat fissure diamond burs to remove amalgam and composite, but not when removing tooth structure. When amalgam and composite were removed without water coolant, the tungsten carbide burs resulted in lower IPT changes than when flat fissure diamond burs were used in the same way.
Color Match of a Universal-shade Composite Resin for Restoration of Non-carious Cervical Lesions: An Equivalence Randomized Clinical Trial.
Miranda AO, Favoreto MW, Matos TP … +6 more , Castro AS, Kunz P, Souza JL, Carvalho P, Reis A, Loguercio AD
Oper Dent · 2024 Jan · PMID 38057996 · Publisher ↗
PURPOSE: The objective of this double-blind, split-mouth, randomized clinical trial was to evaluate the color match of a single-shade composite resin Admira Fusion X-tra in comparison with a multi-shade composite resin A...
PURPOSE: The objective of this double-blind, split-mouth, randomized clinical trial was to evaluate the color match of a single-shade composite resin Admira Fusion X-tra in comparison with a multi-shade composite resin Admira Fusion in non-carious cervical lesion restorations (NCCLs). METHODS AND MATERIALS: One hundred and twenty restorations were performed on NCCLs with two restorative materials (n=60). After prophylaxis, the teeth were isolated with a rubber dam, and one universal adhesive was applied in the selective enamel etching strategy. For both groups, the restorations were inserted incrementally and light-cured. The values of the coordinates L*, a*, and b* in the cervical third before vs after the restorations and cervical vs middle third after the restorations were evaluated using a digital spectrophotometer after the coordinate values were used to calculate the CIEDE (ΔE00). The restorations were evaluated at baseline and after 7 days of clinical performance according to the FDI criteria. Statistical analysis was performed using the Chi-square test for all parameters. Color change was analyzed by Student t-test for paired samples (α=0.05). RESULTS: All restorations were evaluated after 7 days. Regarding the color measurement, no significant difference was observed when Admira Fusion was compared to Admira Fusion X-tra for any of the comparisons performed (p>0.05). However, the values of ΔE00 in the cervical third before vs after the restorations were higher when compared with ΔE00 observed when the cervical vs middle third after restorations were compared. All restorations received the score "clinically very good" after 7 days for all outcomes, including the subjective color match, when evaluated for FDI criterion. CONCLUSIONS: The single-shade composite resin used achieves the same color match when compared to a multi-shade composite resin after 7 days in NCCLs.
The Effect of a Deproteinizing Pretreatment on the Bonding Performance and Acid Resistance of a Two-step Self-etch Adhesive on Eroded Dentin.
Yang Y, Inoue G, Hosaka K … +4 more , Tichy A, Ikeda M, Tagami J, Shimada Y
Oper Dent · 2024 Jan · PMID 38019217 · Publisher ↗
OBJECTIVES: This study evaluated how deproteinization using sodium hypochlorite (6% NaOCl) or hypochlorous acid (50 ppm HOCl) with or without the subsequent use of an arylsulfinate salt-containing agent (Clearfil DC Acti...
OBJECTIVES: This study evaluated how deproteinization using sodium hypochlorite (6% NaOCl) or hypochlorous acid (50 ppm HOCl) with or without the subsequent use of an arylsulfinate salt-containing agent (Clearfil DC Activator; DCA; Kuraray Noritake Dental) affects the micro-tensile bond strength (μTBS) and formation of an acid-base resistant zone (ABRZ) of a two-step self-etch adhesive on eroded dentin. METHODS: Coronal dentin surfaces of sound human molars were exposed to 48 cycles of demineralization (1% citric acid; 5 minutes) and remineralization (buffer solution with pH=6.4; 3.5 hours). They were then assigned to experimental groups according to the pretreatment used: none (negative control), NaOCl, NaOCl+DCA, HOCl, and HOCl+DCA. Sound dentin surfaces with no pretreatment were used as a positive control. The dentin surfaces were bonded with Clearfil SE Bond 2 (Kuraray Noritake Dental), and μTBS was measured either after 24 hours or 20,000 thermal cycles (TC). The μTBS data were statistically analyzed using a mixed-model analysis of variance (ANOVA) and t-tests with Bonferroni correction. Failure mode was determined with scanning electron microscopy (SEM), which was also used for the observation of ABRZ. RESULTS: Among experimental groups, there was no significant difference between the negative control, HOCl, and HOCl+DCA after 24 hours, but the HOCl-pretreated groups exhibited significantly higher μTBS than the negative control after TC (p<0.01). Pretreatment with NaOCl and NaOCl+DCA resulted in significantly higher μTBS (p<0.001), but the highest μTBS was measured on sound dentin (p<0.001). TC decreased μTBS significantly in all groups (p<0.001) except for sound dentin and NaOCl+DCA (p>0.05). Adhesive failures prevailed in eroded groups, whereas cohesive failures were predominant on sound dentin. ABRZ was recognized in all groups but marked morphological differences were observed. CONCLUSIONS: The combined use of 6% NaOCl and the arylsulfinate salt-containing agent partially reversed the compromised bonding performance on eroded dentin, while the effect of 50 ppm HOCl was negligible.
Post-cure Heat Treatments Influence the Mechanical and Optical Properties of Acrylic and Bis-acryl Composite Resins.
Morgado LB, Pedrosa MS, Medeiros IS
Oper Dent · 2024 Jan · PMID 38019216 · Publisher ↗
OBJECTIVE: To evaluate the influence of post-cure heat treatments (PCHT) on Knoop microhardness (KHN) and color change of bis-acryl composite resin (Protemp 4 - 3M ESPE, USA and PrimmaArt - FGM, Brazil) and chemically ac...
OBJECTIVE: To evaluate the influence of post-cure heat treatments (PCHT) on Knoop microhardness (KHN) and color change of bis-acryl composite resin (Protemp 4 - 3M ESPE, USA and PrimmaArt - FGM, Brazil) and chemically activated acrylic resins (Dencôr - Clássico, Brazil, and Duralay - Cotia, Brazil). METHODS AND MATERIALS: Specimens (12×1 mm) were prepared for each material (n=10/group). Thirty minutes after curing, the specimens were subjected to PCHT for 10 minutes at 70°, 100°, or 130°C. The control group was kept at room temperature (24°C) for the same amount of time. KHN was analyzed 24 hours after PCHT (n=10). Following Commission Internationale de l'Éclairage (CIE) Delta E 2000 (CIEDE2000 [ΔE00]), color measurements were obtained at three time points: 1. after polymerization; 2. after PCHT; and 3. after 30 days of storage in water, coffee, or red wine. Data for each material were analyzed by one-way analysis of variance (ANOVA) (p<0.05). RESULTS: The PCHT at 130°C produced the highest KHN values. Except for the 70°C groups from Dencôr and Protemp, all PCHTs increased the initial color values (p>0.05). In general, chemically activated acrylic resins showed an increase in color stability when subjected to PCHT (p>0.05). For bis-acryl composite resin, PCHT did not influence color stability (p<0.05). CONCLUSION: Overall, the results showed that PCHT increased the tested materials' color changes and Knoop microhardness. However, except for PCHT at 130°C in Duralay, the color changes remained within acceptable values. The PCHT treatment resulted in better color stability for most of the composite resins studied.
Influence of Application Modes on Increasing Bond Strength Longevity of Self-etching and Universal Adhesive Systems to Enamel.
Falcione DL, Pena CE, Turssi CP … +4 more , França F, Amaral FD, Tagami J, Basting RT
Oper Dent · 2024 Jan · PMID 38019213 · Publisher ↗
The present study aimed to evaluate the influence of application mode on the short-term microshear bond strength longevity of self-etching and universal adhesive systems to enamel, the failure mode, and the resulting ena...
The present study aimed to evaluate the influence of application mode on the short-term microshear bond strength longevity of self-etching and universal adhesive systems to enamel, the failure mode, and the resulting enamel surface micromorphology. Ninety enamel surfaces were obtained from sound third molars, planed, and randomly assigned to nine groups, according to the application mode and the adhesive system (n=10). There were three primer application modes: according to the manufacturer's recommended application time (control), using double the application time recommended for the primer and selective enamel etching. The adhesive systems used were: Clearfil SE Bond (Kuraray), FL-Bond II (SHOFU), and Futurabond U (Voco). At least two resin-bonded composite cylinders (Grandioso Light Flow, Voco) were placed on each enamel surface, and then evaluated for microshear bond strength at 24 hours and 180 days of storage in solution body fluid (SBF) at pH 7.4. Failure modes were evaluated with a stereoscopic microscope at 20× magnification. A micromorphological analysis of the enamel surface was performed under a scanning electron microscope at 5000× magnification before and after the treatments. Mixed models for repeated measures over time showed significant interaction among application modes, adhesive systems, and time periods (p=0.0331). The bond strength of FL-Bond II adhesive to enamel observed after performing selective enamel etching was significantly higher than that observed after applying the control treatment (p=0.0010) at both 24 hours and 180 days. However, no significant difference was observed between the application of this same adhesive at double the time recommended by the manufacturer and the other two application modes (p>0.05). There was also no significant difference in the microshear bond strength for the enamel treatments applied using Clearfil SE Bond and Futurabond U (p>0.05). A significant reduction in bond strength to enamel was observed at the 180-day storage time for all the adhesive systems when selective enamel etching was performed (p<0.0001). No significant association was observed between the adhesive system failure mode and the enamel treatments (p=0.1402 and p=0.7590 for 24 hours and 180 days, respectively). The most prevalent failure was the adhesive type.
Clinical Performance of Minimally Invasive Monolithic Ultratranslucent Zirconia Veneers: A Case Series up to Five Years of Follow-up.
Silva NR, Araújo G, Moura D … +7 more , Araújo L, Gurgel BV, Melo RM, Bottino MA, Özcan M, Zhang Y, Souza R
Oper Dent · 2023 Nov · PMID 37961016 · Publisher ↗
There is a lack of reports in the literature on the long-term clinical performance of ultratranslucent zirconia, especially considering its use in manufacturing monolithic veneers. The purpose of this case series is to d...
There is a lack of reports in the literature on the long-term clinical performance of ultratranslucent zirconia, especially considering its use in manufacturing monolithic veneers. The purpose of this case series is to describe the aesthetic treatment steps of three patients with minimally invasive ultratranslucent zirconia veneers and to report the clinical findings up to five years. Three patients (woman: 2, man: 1; mean age: 30 years) unsatisfied with their dental aesthetics sought dental treatment. The treatment plan involved cementing ultratranslucent zirconia veneers. Air-abrasion was performed on the internal surface of zirconia with alumina particles coated by silica (silicatization), followed by silane and adhesive applications for the adhesive cementation. All veneers were adhesively cemented to enamel with resin cement (Variolink Esthetic, Ivoclar). The patients were clinically evaluated annually considering the Ryge modified/ California Dental Association criteria. After a mean follow-up of 4.33 years (4-5 years), a survival rate of 100% was detected for the 28 minimally invasive ultratranslucent zirconia veneers cemented in the 3 patients. There were no absolute failures such as debonding, veneer fracture, or secondary caries. Superficial marginal discoloration was observed in one element (maxillary left lateral incisor) of one patient. Ultratranslucent zirconia is a viable option for manufacturing veneers due to its excellent clinical performance and longevity. However, further long-term clinical studies are essential to consolidate this material as an option for esthetic restorations.
Improving Bond Strength of Translucent Zirconia Through Surface Treatment With SiO2-ZrO2 Coatings.
Du Q, Cui T, Niu G … +2 more , Qui J, Yang B
Oper Dent · 2023 Nov · PMID 37961015 · Publisher ↗
BACKGROUND: Translucent monolithic zirconia ceramics have been applied in dental clinics due to their esthetic translucent formulations and mechanical properties. Considering inherent ceramic brittleness, adhesive bondin...
BACKGROUND: Translucent monolithic zirconia ceramics have been applied in dental clinics due to their esthetic translucent formulations and mechanical properties. Considering inherent ceramic brittleness, adhesive bonding with resin composite increases the fracture resistance of ceramic restorations. However, zirconia is a chemically stable material that is difficult to adhesively bond with resin. OBJECTIVES: To investigate the influences of SiO2-ZrO2 coatings on adhesive bonding of zirconia and the surface characterization of those coatings. METHODS AND MATERIALS: Translucent zirconia discs were classified into groups based on surface treatments: CT (control), SB (sandblasting), C21(SiO2:ZrO2=2:1), C11(SiO2:ZrO2=1:1), and C12 (SiO2:ZrO2=1:2) (n=10). Surface characterization of coatings on zirconia were analyzed by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), surface roughness assessment (Ra), X-ray diffraction (XRD), water contact angle (WCA), translucency parameter (TP), and shear bond strength (SBS). Two-way ANOVA for shear bond strength results and ANOVA for Ra and WCA were performed. RESULTS: SEM images revealed SiO2 islands on zirconia disks coated with SiO2-ZrO2. Surface roughness of C12, C11, and C21 groups was significantly larger than those of groups SB and CT (p<0.05). XRD results showed that phase transformation of zirconia disks was detected only in the SB group. In addition, SiO2-ZrO2 coatings reduced WCA. The translucency decreased only in group C21. Group C11 showed the highest shear bond strength under both aging conditions. CONCLUSION: SiO2-ZrO2 coating is a promising method to enhance the adhesive resin bonding of translucent zirconia without causing phase transformation of translucent zirconia.
Influence of the Crystallization Firing Process on Marginal and Internal Adaptation of Silicate-based Glass-ceramic Inlays Fabricated With a CAD/CAM Chairside System.
Kobayashi M, Niizuma Y, Sugai R … +1 more , Manabe A
Oper Dent · 2023 Nov · PMID 37882476 · Publisher ↗
OBJECTIVE: Computer-aided design/computer-aided manufacturing (CAD/CAM) systems are widely used in dental treatment. Clinicians can use chairside CAD/CAM technology, which has the advantage of being able to fabricate inl...
OBJECTIVE: Computer-aided design/computer-aided manufacturing (CAD/CAM) systems are widely used in dental treatment. Clinicians can use chairside CAD/CAM technology, which has the advantage of being able to fabricate inlays on the same day. We aimed to evaluate the effects of crystallization firing processes, fabrication methods (one-step and two-step), and materials on marginal and internal adaptations of silicate-based glass-ceramic all-ceramic inlays fabricated with CAD/CAM chairside systems. METHODS: Ten artificial mandibular left first molars were prepared with standardized ceramic class II mesialocclusal (MO) inlay cavities. Optical impressions were obtained using CEREC Omnicam Ban. IPS e-max CAD (IE), (Ivoclar Vivadent, Schaan, Liechtenstein), Initial LiSi Block (LS) (Hongo, Bunkyoku, Tokyo, Japan), VITA Suprinity (SP), (Vita Zahnfabrick, Bad Säckingen, Germany), and Celtra Duo (CD) (Ivoclar Vivadent, Schaan, Liechtenstein) (n=10) were milled using CEREC MC XL (Bensheim, Germany). IE and SP were crystallization-fired using CEREC Speed Fire. The silicone replica technique was used for the measurement of internal (axial and pulpal walls) and marginal (cervical and occlusal edge) adaptations. The adaptations were measured using a thin layer of light-body polyvinyl siloxane impression material placed between the master tooth inlay preparation and restoration. Marginal and internal adaptations of IE, LS, SP, and CD were measured using a stereomicroscope (500×). For IE and SP, marginal and internal adaptations were measured before and after the crystallization firing process. Data analyses were conducted using one-way ANOVA and the Tukey test. For IE and SP, marginal and internal adaptations before and after the crystallization firing process were analyzed using the t-test. The significance level was set at α=0.05. RESULTS: One-way ANOVA revealed statistically significant differences in occlusal and cervical edge marginal adaptations among the material groups (p<0.001). The Tukey HSD test revealed a significant difference in marginal occlusal and cervical edge adaptations between LS and CD groups and IE and SP groups (p≤0.05). For IE and SP inlays, the t-test revealed a significant difference between occlusal and cervical edge adaptations before the crystallization firing process and those after the crystallization firing process, with the latter group showing a more significant discrepancy in adaptation than the former group (p≤0.05). CONCLUSIONS: Fabrication methods (one- and two-step) affected the marginal adaptation compatibility but not internal compatibility of MO inlays. The crystallization firing process affected the marginal adaptation of inlays using lithium silicate or lithium disilicate glass-ceramics. However, adaptation to the cavity was considered clinically acceptable for all materials.
Effect of Tooth Bleach on Dentin Fatigue Resistance in Situ.
Fitzgerald JM, Souza G, Tam L
Oper Dent · 2023 Nov · PMID 37881145 · Publisher ↗
BACKGROUND: Negative effects of bleaching on dentin have previously been reported in vitro. OBJECTIVE: The purpose of this study was to determine the effect of carbamide peroxide bleaching on dentin fatigue resistance us...
BACKGROUND: Negative effects of bleaching on dentin have previously been reported in vitro. OBJECTIVE: The purpose of this study was to determine the effect of carbamide peroxide bleaching on dentin fatigue resistance using a clinically relevant in situ model. METHODS AND MATERIALS: Following research ethics board approval, 60 human teeth requiring extraction were collected. Sterilized human dentin specimens were cut (1.2x1.2x10 mm) and secured into customized bleaching trays to be used by study participants. Participants were randomly assigned to either bleach (10% carbamide peroxide, n=23) or control (gel without bleach, n=26) treatment groups. Treatment was applied to the bleaching trays and worn overnight by participants for 14 days. After treatment completion, dentin specimens were removed from the bleaching trays and subjected to fatigue testing (10 N, 3 mm/s, 2x105 cycles) while submerged in artificial saliva. Kaplan-Meier survival analysis was conducted to compare the number of cycles to failure during fatigue testing in both groups. A log rank test was run to determine if there were differences in the survival distribution between the two groups (α<0.05). RESULTS: The median number of cycles to failure was 352 ± 202 and 760 ± 644 for the bleach and control groups, respectively. The survival distributions for the two groups were significantly different (p=0.020). Dentin fatigue resistance was significantly lower in the bleach group compared to the control. CONCLUSIONS: Direct bleaching of human dentin using an at-home tray bleaching protocol in situ reduced dentin fatigue resistance. This has implications for tooth fracture risk and longevity.
Effect of a Toothpaste for Sensitive Teeth on the Sensitivity and Effectiveness of In-office Dental Bleaching: A Randomized Clinical Trial.
Américo MA, Portella FF, Zimmer R … +5 more , Garcia FR, Porto DJ, Barbosa VL, Oballe H, Reston EG
Oper Dent · 2023 Nov · PMID 37881142 · Publisher ↗
OBJECTIVES: The present study aimed to evaluate the desensitizing effect of toothpaste for sensitive teeth on patient tooth sensitivity and on bleaching efficacy of the 38% hydrogen peroxide bleaching agent used for in-o...
OBJECTIVES: The present study aimed to evaluate the desensitizing effect of toothpaste for sensitive teeth on patient tooth sensitivity and on bleaching efficacy of the 38% hydrogen peroxide bleaching agent used for in-office bleaching compared to a regular toothpaste in a randomized clinical trial. METHODS AND MATERIALS: Forty-eight patients having maxillary right central incisors with darkness greater than A1 were selected for the present double-blind randomized clinical trial. Patients were randomly allocated into two groups: the placebo group, which used regular toothpaste, and the experimental group, which used sensitivity toothpaste. The intervention consisted of applying toothpaste with the aid of an individual tray for a period of 4 minutes daily, starting one week before the first bleaching session and interrupting use immediately after the second session. After allocation to one of the groups, individuals received in-office dental bleaching with a 40-minute application of 38% hydrogen peroxide for two sessions with an interval of one week. The incidence and intensity of sensitivity were assessed using a visual analogue scale and a numeric analogue scale. Sensitivity was measured immediately before each session, 1 hour, 24 hours, and 48 hours after each bleaching session and four weeks after the second bleaching session. Tooth shade was evaluated using a spectrophotometer and by comparison with the VITA Classical Shade Guide (Vita Zahnfabrik, Bad Säckingen, Germany). Tooth shade was evaluated before the first bleaching session, one week after the first bleaching session, one week after the second bleaching session and four weeks after the second bleaching session. Participants and professionals who performed the bleaching, shade, and sensitivity assessments were blinded to the group of patients they were treating or assessing. For the incidence of hypersensitivity, the results were evaluated by comparing the groups at different evaluation times with the Mann-Whitney test for comparison between groups, the Friedman test for repeated measures, and the Tukey test for comparison of times. Shade change on the guide was analyzed using the Mann-Whitney test for comparison between groups and the Wilcoxon test for comparison between times. Shade change by the spectrophotometer was analyzed using the t-test for comparison between groups and the paired t-test for comparison between times. All analyses were performed with a significance level of 5%. RESULTS: There was no difference in the pattern of dental hypersensitivity between groups. For all shade measures, there was no difference between the bleaching results, and no statistically significant difference was observed between the study groups. CONCLUSION: The use of arginine-based desensitizing toothpaste did not interfere with the bleaching ability of hydrogen peroxide and was not effective in reducing the sensitivity caused by in-office tooth bleaching.
Printed Digital Wax-up Model as a Blueprint for Layered Pressed-ceramic Laminate Veneers: Technique Description and Case Report.
Jurado CA, Villalobos-Tinoco J, Mekled S … +2 more , Sanchez R, Afrashtehfar KI
Oper Dent · 2023 Nov · PMID 37881104 · Publisher ↗
This article presents a clinical technique for transferring Digital Smile Design (DSD) information and a digital wax-up to fabricate highly personalized ceramic laminate veneers. The hybrid workflow of digitally designed...
This article presents a clinical technique for transferring Digital Smile Design (DSD) information and a digital wax-up to fabricate highly personalized ceramic laminate veneers. The hybrid workflow of digitally designed wax-up and conventional hand-crafted veneers is showcased in a female adult who sought to improve her smile due to maxillary anterior incisal wear. The ceramic veneers, layered by feldspathic porcelain, followed the contours and shade blueprint planned with the digital wax-up. The DSD improved the harmony of the facial-and-smile relationship, and the ceramic restorations fulfilled the patient's esthetic and functional demands. Guides based on the printed model with the digitally designed wax-up can provide a reference for pressed lithium disilicate veneers layered with feldspathic porcelain.
Flexural Strength of Conventional or Bulk-fill Resin Composite Repaired with High- or Low-viscosity Restorative Materials.
Foscarini AV, Barros LS, Turssi CP … +3 more , França F, Basting RT, Vieira WF
Oper Dent · 2023 Nov · PMID 37881103 · Publisher ↗
OBJECTIVE: To evaluate the flexural strength of two types of high-viscosity resin composites (conventional or bulk-fill) that were repaired with either high-viscosity composites (conventional or bulk-fill) or low-viscosi...
OBJECTIVE: To evaluate the flexural strength of two types of high-viscosity resin composites (conventional or bulk-fill) that were repaired with either high-viscosity composites (conventional or bulk-fill) or low-viscosity composites (conventional or bulk-fill) of the same manufacturer (3M Oral Care, St Paul, MN, USA). METHODS AND MATERIALS: Specimens (25 mm × 2 mm × 2 mm) of both conventional nanofilled resin (Filtek Z350XT), and bulk-fill nanofilled resin (Filtek One Bulk Fill) were prepared. After fracture of the specimens in the 3-point bending test (initial), half of the specimens were repaired immediately afterwards (24 hours), and the other half were repaired after 6 months of storage in distilled water. Repairs were performed with (n=15) high-viscosity resin composites (Filtek Z350XT, Filtek One Bulk Fill), or their low-viscosity versions (Filtek Supreme XT Flow, Filtek Bulk Fill Flowable Restorative). The repair was performed by roughening the surface and applying phosphoric acid, silane, and adhesive. The bending test (results reported in MPa) was performed in a universal testing machine, and the fracture pattern was determined. Data were evaluated by generalized linear models, chi-square test and the Fisher exact test (α=0.05). RESULTS: There was no significant difference between the former pair of high-viscosity resins in terms of initial flexural strength (p=0.42). The repairs performed with low-viscosity resin composites after 24 hours or 6 months obtained higher MPa values compared with those using high-viscosity composites (p=0.0006). There was a significant decrease in MPa values when the repair was performed after 24 hours and an increase after 6 months, regardless of the material (p<0.0001). After 6 months, fractures involving the old (conventional) resin were more frequent in the repair performed with bulk-fill resin composites compared with the conventional composites (p=0.02). CONCLUSIONS: Considering the tested products, the material to be repaired did not influence the flexural strength of the repair composite; however, the use of the low-viscosity resin composites resulted in greater flexural strength of the repaired material. The repair of the aged composite resulted in an increase in its flexural strength, regardless of the material repaired or used to perform the repair.
Effects of Hydrofluoric Acid Concentrations, Commercial Brands, and Adhesive Application on the Bond Strength of a Resin Luting Agent to Lithium Disilicate Glass Ceramic.
Dos Santos D, Pacheco RR, Komegae GH … +4 more , da Silva JA, Lima D, Pini N, Sundfeld D
Oper Dent · 2023 Nov · PMID 37881098 · Publisher ↗
OBJECTIVES: To evaluate the surface topography/roughness and bond strength of a resin luting agent to a lithium disilicate glass ceramic after etching with different concentrations of hydrofluoric acid (HF) and commercia...
OBJECTIVES: To evaluate the surface topography/roughness and bond strength of a resin luting agent to a lithium disilicate glass ceramic after etching with different concentrations of hydrofluoric acid (HF) and commercial brands. METHODS: For bond strength evaluation, 260 lithium disilicate glass ceramic (EMX) discs were randomly distributed into 13 groups based on concentrations of HF and commercial brands (n=20): 5% and 10%, Lysanda (LY5 and LY10); 5% and 10%, Maquira (MA5 and MA10); 5% and 10%, FGM (FG5 and FG10); 4.8%, Ivoclar Vivadent (IV5); 5% and 10%, PHS do Brasil (PH5 and PH10); 5% and 10%, BM4 (BM5 and BM10); 9%, Ultradent Inc (UL10); and Dentsply (DE10). A further random distribution (n=10) was made based on the application (+) or absence (-) of an adhesive layer. Resin luting agent cylinders (1 mm in diameter) were added on EMX surfaces, light-cured, and stored for 24 hours in deionized water at 37°C. On a universal testing machine (DL 500, EMIC), specimens were submitted to a microshear bond strength test at a crosshead speed of 1 mm/min until failure. A representative etched EMX disc from each group underwent surface topography analysis using field-emission scanning electron microscopy (n=1), and five (n=5) etched EMX discs from each group were tested for surface roughness. Data were statistically analyzed using analysis of variance and Tukey test (α=0.05). RESULTS: A less conditioned and smoother surface was observed for 5% HF compared to 10%. Additionally, commercial brands of HF were shown to affect bond strength. When the adhesive layer was not used (-), a 10% concentration promoted higher bond strengths to EMX. However, when adhesive was applied (+), the concentrations of HF and commercial brands had no effect on bond strength results. CONCLUSIONS: A 10% concentration of HF results in higher bond strength than a 5% concentration. If an adhesive layer is applied, neither this distinction nor the influence of commercial brands is observed.
Effect of Commercial Mouth Rinses on Physical Properties of Conventional and Bulk-fill Resin Composites.
Derigi LP, Barros LS, Sugii MM … +4 more , Turssi CP, França F, Basting RT, Vieira WF
Oper Dent · 2023 Nov · PMID 37881067 · Publisher ↗
OBJECTIVE: To evaluate the effects of commercial mouth rinses on color, roughness, sorption (SR), and solubility (SL) of resin composites. METHODS AND MATERIALS: Disc-shaped specimens (stage I: 6 mm × 2 mm; stage II: 10...
OBJECTIVE: To evaluate the effects of commercial mouth rinses on color, roughness, sorption (SR), and solubility (SL) of resin composites. METHODS AND MATERIALS: Disc-shaped specimens (stage I: 6 mm × 2 mm; stage II: 10 mm × 1.5 mm) were made from the following resin composites (n=10): conventional nanofilled (Filtek Z350XT, 3M Oral Care), conventional nanohybrid (Luna, SDI), bulk-fill nanofilled (Filtek One Bulk-Fill, 3M Oral Care), and bulk-fill nanohybrid (Aura Bulk-Fill, SDI) exposed to distilled water (control), blue mouth rinse without alcohol (Colgate Total 12 Clean Mint, Colgate-Palmolive), or blue mouth rinse with alcohol and essential oil (Listerine Tartar Control, Johnson & Johnson). In stage I, tests were performed at the baseline, and after the immersion in solution time points to evaluate coordinates of the CIEL*a*b* system (ΔL*, Δa*, Δb*), general color change (ΔEab, ΔE00, and ΔSGU), and surface roughness (Ra). In stage II, SR and SL were evaluated (ISO 4049:2019) after immersion in the solutions for 7 days. The results were evaluated by generalized linear models (Ra, SR), Kruskal-Wallis, and Dunn tests (color, SL), with α = 0.05. RESULTS: There were no significative differences for Ra between the solutions. Both mouth rinses promoted significantly negative ΔL* (Luna), Δa* (Filtek One Bulk-fill), and Δb* (all materials except conventional nanofilled resin composite). Mouth rinse without alcohol promoted significantly negative Δa* on all resin composites tested. Both mouth rinses promoted higher ΔEab and ΔE00 for bulk-fill resin composites compared to control. Mouth rinse with alcohol caused higher ΔSGU for bulk-fill nanofilled resin composite. It also promoted greater SR in all the resin composites compared with mouth rinse without alcohol and higher SR in nanohybrid resin composites compared with control. Both mouth rinses promoted higher SL values in Luna and differed significantly from control. CONCLUSIONS: The physical properties were manufacturer dependent and mediated by mouth rinses. The mouth rinses promoted color changes in the resin composites, pointing out that bulk-fill resin composites were more affected by these effects, especially when the mouth rinse contained essential oil and alcohol.
Evaluation of Glazing and Polishing Systems for Novel Chairside CAD/CAM Lithium Disilicate and Virgilite Crowns.
Jurado CA, Arndt K, Azpiazu-Flores FX … +4 more , Faddoul F, França R, Fischer NG, Watanabe H
Oper Dent · 2023 Nov · PMID 37881035 · Publisher ↗
OBJECTIVE: The purpose of this study was to evaluate the effectiveness of glazing, two zirconia, and two lithium disilicate polishing systems on surface roughness of a CAD/CAM lithium disilicate and virgilite ceramic wit...
OBJECTIVE: The purpose of this study was to evaluate the effectiveness of glazing, two zirconia, and two lithium disilicate polishing systems on surface roughness of a CAD/CAM lithium disilicate and virgilite ceramic with atomic force microscopy (AFM) and visual assessment performed by dental students and faculty. METHODS AND MATERIALS: Sixty maxillary right central incisor crowns made of a novel chairside CAD/CAM lithium disilicate and virgilite (CEREC Tessera) were milled for glazing and polishing. The crowns were divided into six groups: no polishing/glazing provided (NoP/G); glazed (GZ); glazed and polished with Brasseler Dialite LD Lithium Disilicate (DiLD); glazed and polished with Meisinger Luster Lithium Disilicate (LuLD); glazed and polished with Brasseler Dialite ZR Zirconia (DiZR); and glazed and polished with Meisinger Luster Zirconia (LuZR). Surfaces were scanned with AFM to measure roughness (Ra) and root mean square roughness (Rq) and generate micrographs. Crowns were visually assessed by 10 dental students and 10 dental school faculty members to determine clinical acceptableness. RESULTS: Glazing and all polishing kits significantly reduced Ra and Rq compared to no polishing/glazing. No significant Ra differences were found between glazing and all polishing kits (p>0.05). DiZR significantly reduced Rq compared to other groups (p<0.05). Visual assessment showed that GZ, LuLD, and DiZR were the most clinically acceptable crowns. CONCLUSION: Polishing and glazing considerably improve the surface smoothness of maxillary central incisor crowns fabricated out of a chairside CAD/CAM lithium disilicate and virgilite ceramic. Altogether, zirconia polishing systems provided smoother and more clinically acceptable surfaces than the lithium disilicate kits.
Influence of Mono- and Multiwave Light-curing Units on the Microhardness and Degree of Conversion of Light-cured Resin Cements.
Zancopé K, Borges G, Ribeiro M … +3 more , Miranda RR, Peres TS, Soares CJ
Oper Dent · 2023 Nov · PMID 37881034 · Publisher ↗
OBJECTIVES: This study evaluated the Knoop hardness (KH, N/mm2) and degree of conversion (DC, %) on the margins of light-cured resin cements with different photoinitiators using a single light-curing unit (LCU) with two...
OBJECTIVES: This study evaluated the Knoop hardness (KH, N/mm2) and degree of conversion (DC, %) on the margins of light-cured resin cements with different photoinitiators using a single light-curing unit (LCU) with two heads (mono- and multiwave). METHODS AND MATERIALS: Three types of resin cements were used with different photoinitiators: Megalink Esthetic (Odontomega, São Paulo, Brazil) with a camphorquinone photoinitiator; Allcem Veneer (FGM, Joinville, Brazil) with the Advanced Polymerization system (APS), and Variolink Esthetic LC (Ivoclar Vivadent, Schaan, Liechtenstein). Thirty samples were collected and divided into six groups (n=5 each). The resin cement samples were made into the shape of a maxillary right central incisor and photoactivated under a 0.5-mm-thick ceramic sheet. A single LCU (Radii Xpert, SDI) with two heads (mono- and multiwave) was used. The tip of the LCU was positioned at the center of the sample in a standardized manner. Raman spectroscopy was performed to evaluate the DC, and KH was evaluated through the Knoop microhardness test. Five regions were evaluated: cervical, mesial, buccal (center), distal, and incisal. RESULTS: There was a significant difference in the DC only for the type of cement (p<0.001), indicating that the cement with the APS photoinitiator presented excellent results. There were significant differences in the type of cement (p<0.001), type of light (p<0.001), region (p<0.001), and the interaction between the type of cement and type of light (p<0.001). The resin cement with the APS photoinitiator cured with monowave light showed the highest KH values. The beam profiles of all groups, with and without the interposition of ceramic and resin cement, were examined by light transmission. CONCLUSIONS: The cement with the APS photoinitiator presented the best results with respect to the DC and KH. In comparison with mono- and multiwaves, the LCU may not be a determining factor for the properties of light-cured resin cements. The buccal region showed the best results for DC and KH, indicating the need for a greater amount of light-curing at the cementation margins.
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