HA006 - Hatton
Área: 4 - Ortodontia

Maxillary dentoskeletal outcomes of the expander with the differential opening and the fan-type expander: a randomized clinical trial
Massaro C, Ruellas ACO, Cevidanes LHS, Yatabe MS, Janson G, Miranda F, Lauris JRP, Garib DG
Ortodontia - UNIVERSIDADE FEDERAL DE GOIÁS
Conflito de interesse: Autodeclarado "Patente referente ao expansor com abertura diferencial no nome da autora Daniela Gamba Garib (PI 1101050-9, Instituto nacional de patente e indústria-Brasil)."

The aim of this randomized clinical trial was to compare the maxillary expander with differential opening (EDO) and the fan-type expander (FE) in the mixed dentition by means of cone-beam computed tomography (CBCT) three-dimensional models superimposed on the cranial base. Forty-eight patients with maxillary dental arch constriction were randomly allocated into 2 study groups. Group EDO was composed of 24 patients (mean age of 7.62 years) treated with the EDO. Group FE comprised 24 patients (mean age of 7.83 years) treated with the FE. CBCT scans were acquired before and after rapid maxillary expansion. Three-dimensional dentoskeletal changes were assessed after cranial base superimposition using the software ITK-SNAP and 3D Slicer. T or Mann-Whitney U tests with Holm-Bonferroni correction were used for intergroup comparisons (P<0.05). Maxillary lateral displacements were greater in the EDO group, while the vertical and anteroposterior changes were similar in both groups. The increase in the intercanine distance and the canine buccal inclination were slightly greater in the FE group, while the intermolar changes and the molar buccal inclination were greater in the EDO group.
The expander with differential opening (EDO) produced a greater transversal skeletal expansion compared to the fan-type expander (FE), with similar vertical and anteroposterior effects. Dental changes were greater in the molar region for patients treated with EDO and in the canine region for patients treated with FE.
(Apoio: CAPES  |  FAPs - FAPESP  N° 2017/12911-9  |  NIDCR R01 DE024450)

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HA007 - Hatton
Área: 5 - Materiais Dentários

Nanoscale biomimetic mineralization of bioprinted gelatin methacryloyl for tissue engineering
Balbinot GS, Subbiah R, Athirasala A, Collares FM, Bertassoni LEB
Odontologia Conservadora - UNIVERSIDADE FEDERAL DO RIO GRANDE DO SUL
Conflito de interesse: Não há conflito de interesse

Mimicking the complex structure of bone tissue is key for effective bone regeneration. This study aimed to develop a unique process to 3D bioprint microscale cell-laden scaffolds that mimick the bone nanoscale structure and function with precision and can be delivered via injection for minimally invasive regenerative procedures. Gelatin methacryloyl (GelMA) hydrogels were produced by stereolithography and used as an organic substrate for biomimetic nanoscale mineralization via a proprietary protein-mediated biomimetic mineralization process with osteopontin in a Ca²⁺ and PO₄^3- supersaturated media. Mineralization was optimized for different media, gelMA concentrations, and cross-linking times. The mineral content and mechanical properties were evaluated, and optimized hydrogels were used for dental pulp stem cells (DPSCs) encapsulation. The printability was tested for injectable mineralized microgels production. After the screening, 10wt% gelMA printed for 25s and mineralized in α-MEM was chosen, reaching an elastic modulus of 123.94kPa. Mineralized hydrogels DPSCs viability and differentiation. Injectable flower-shaped microgels (900µm) were successfully printed and mineralized.
The nanoscale mineralization of bone-like cell-laden bioprinted microgels was demonstrated for the first time. The obtained nanostructure evidence the ability of these materials to mimic the intra- and extracellular environments of bone. Mineralized microgels were successfully produced for injectable minimally invasive regenerative procedures.

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HA008 - Hatton
Área: 5 - Dentística

Color stability in relation to degree of conversion and monomer elution for different commercial composites
Cardoso LI, Collares FM, Spohr AM, Mota EG, Burnett Júnior LH
Clínico - PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO GRANDE DO SUL
Conflito de interesse: Não há conflito de interesse

This study aimed to evaluate the color stability (∆E) of three commercial brands of composite resins when immersed in distilled water, within 24 hours, 30 days and 180 days, as well as the degree of monomer conversion and BisGMA component release. Five specimens of each resin shade were made for color stability evaluation (Easyshade 4.0, Vita) and three specimens for the degree of monomer conversion evaluation (FTIR). Each increment of resin in the specimens was light-cured for 20s using a polywave LED and these were then stored in distilled water at 37°C after photoactivation. A color scale pattern was made from the material studied, following the Vita (Vita) scale, to determine a standard of comparison. The elution of BisGMA was analyzed by liquid chromatography with mass spectrometer. The three-way ANOVA test allowed us to observe that the interaction between time/shade/brand was significant (p = 0.0001), with all the studied resins showing color changes in relation to the pattern in the studied periods. Empress Direct was the only one to display ∆E≥2.7over the 180 days on shades B1 and A1, and there was no significant correlation between degree of conversion, ∆E and BisGMA elution. There was a significant direct correlation between degree of conversion and ∆E in 30 days and inverse in 180 days.
Thus, it is suggested that there is a stabilization of the resinous material after 30 days and thus, a balance of its optical properties.
(Apoio: CAPES)

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HA009 - Hatton
Área: 6 - Prótese

Effect of different surface treatments and glaze application on the wear resistance of a stained hybrid ceramic
Tribst JPM, Dal-Piva AMO, Anami LC, Kleverlaan CJ, Bottino MA
Odontologia - UNIVERSIDADE DE TAUBATÉ
Conflito de interesse: Não há conflito de interesse

To evaluate the effect of surface treatment and glaze application on the external staining wear resistance of a hybrid ceramic. Thirty-two (32) specimens (14 x 10 x 3 mm) were glued to a wheel device and divided into 8 groups according to the surface treatment prior to the staining (polishing: Pol, acid etching: Ac, sandblasting: Sd, or self-etching silane: Ses) and glaze application (with: gl or without: -gl). After the wear test on the ACTA wear machine, the staining wear rate was determined during seven intervals of 20,000 cycles, using a profilometer. The three-body wear rates were analyzed using three-way ANOVA and post-hoc Tukey test, all with α=5%. Scanning Electron Microscopy (SEM) analysis was performed to access the surface wear profile. The three-body wear rates were affected by surface treatment*glaze application*number of cycles interaction (p < 0.001). 100% of the staining was removed at 20,000 for Pol, at 40,000 for Pol+gl, at 60,000 for Ses+gl, at 80,000 for Ac, at 100,000 for Sd and Ses, at 120,000 for Ac+gl and at 140,000 for Sd+gl. SEM showed similar worn surface profiles for the tested groups and the glaze removal occurred after 140,000 cycles.
The sandblasting followed by glaze application as surface treatment showed more suitable capability to maintain the external staining on hybrid ceramic surface. The glaze application did not protect the stain regardless the ceramic surface treatment performed.
(Apoio: FAPs - FAPESP  N° 18/07404-3)

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HA010 - Hatton
Área: 6 - Prótese

Changes in zirconia surface architecture and evaluation of shear bond strength with veneering ceramic after plasma treatment
Bitencourt SB, Santos DM, Bastos NA, Bonfante EA, Rangel EC, Pesqueira AA
Materiais Odontológicos e Prótese - UNIVERSIDADE ESTADUAL PAULISTA - ARAÇATUBA
Conflito de interesse: Não há conflito de interesse

To characterize the zirconia (Y-TZP) surface submitted to different surface treatments (with and without plasma associations) and to evaluate the shear bond strength (SBS) with the veneering ceramic (VC) after different aging periods. 301 Y-TZP specimens were fabricated and distributed into 7 groups (n=43): C (control): no treatment; Al: airborne abrasion with 27 µm Al2O3 particle; L: liner; P: plasma; Al+L: airborne abrasion + liner; Al+P: airborne abrasion + plasma; P+L: plasma + liner. The Y-TZP surface was characterized by SEM, EDS, AFM, roughness, and surface-free energy (SFE). XRD was used to verify the crystal structure after each surface treatment performed. SBS between Y-TZP and the VC was verified after three aging protocols: initial and after hydrothermal aging (autoclave for 5h) and thermal fatigue (30,000 baths - 5-55°C). One- (roughness and SFE) and two-way ANOVA (SBS), and Tukey's HSD test were used as a statistical analysis. For the plasma groups, a homogeneous and full surface coverage was observed on SEM and AFM, with globular formation. Peaks of Si were found for Al, L, Al+L, and P+L groups. Roughness was lower for groups C, P, and Al+P. For SFE, the highest values were found when the liner was applied. The higher monoclinic content was found for Al+L and Al+P. For the initial and after thermal fatigue, the P group presented the highest SBS values.
Plasma treatment itself or associated with liner was capable to deposit a film on the zirconia surface without altering its structure and to improve the SBS with VC, even after aging.
(Apoio: FAPs - FAPESP  N° 2017/13933-6  |  FAPs - FAPESP  N° 2018/24984-3)

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