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OBJECTIVE: This study aimed to enhance the quintessential "five temporomandibular disorder (TMD) symptoms" (5Ts) screener by incorporating frequency options and distinguishing between TMJ and muscle pain. The diagnostic accuracy along with cut-off points for the effective identification of TMDs was also established. METHODS: Participants, aged ≥18 years, were recruited from a university-based hospital. After completing surveys encompassing demographic data and the enhanced 5Ts (with frequency options [5Ts-F] and differentiation of TMJ/muscle pain [6Ts-F]), protocolized interviews and clinical examinations were performed following DC/TMD. The diagnostic accuracy and best cut-off points were determined with the area under the receiver operating characteristic curves (AUCs). RESULTS: 324 participants were recruited (mean age 30.0 ± 11.4 years). Among these, 86.4% had TMDs. 5Ts exhibited high diagnostic accuracy for detecting all TMDs (AUC = 0.92) with sensitivity/specificity values of 83.9%/88.6%. Both 5Ts-F and 6Ts-F had slightly better accuracy (AUCs = 0.95/0.96), comparable sensitivity, and superior specificity (97.7%) compared to 5Ts. The best cut-off points were 1.5 for 5Ts and 2.5 for 5Ts-F/6Ts-F. CONCLUSIONS: Although all three TMD screeners presented high diagnostic accuracy, 5Ts-F/6Ts-F had notably improved specificity. 5Ts scores of >1.5 and 5Ts-F/6Ts-F scores of >2.5 are to be applied for screening the presence of TMDs.
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BACKGROUND: This community-based study investigated the functional, physical and psychosocial impact of Temporomandibular Disorders (TMDs) in adolescents and young adults. It also determined the discriminative capacity of a TMDs-specific oral health related quality of life (OHRQoL) instrument and compared three formats of appraising OHRQoL data. MATERIAL AND METHODS: Subjects were recruited from a local Polytechnic. The presence of TMDs was established with the Fonseca Anamnestic Index (FAI), whilst TMDs-specific OHRQoL was evaluated with the Oral Health Impact Profile-TMDs (OHIP-TMDs). Demographic information, FAI and OHIP-TMDs responses were gathered with an on-line questionnaire. Data was analysed using Mann-Whitney U-test, chi-square test and Spearman's rho correlation with significance level set at 0.05. RESULTS: Data from a total of 244 participants were compiled and examined. The "no TMDs" (NT) group consisted of 140 subjects (119 females; 21 males) with a mean age of 20.41±3.29 years, while the "with TMDs" (WT) group composed of 104 subjects (88 females; 16 males) aged 19.82±3.04 years. Significant differences in median severity scores were observed between subjects with and without TMDs for all OHIP-TMDs domains and total OHIP (p values < 0.001). For appraisal of extent and prevalence, significant differences were again observed (p values < 0.05) with the exception of the functional limitation and handicap domains. CONCLUSIONS: TMDs impacted physical and psychosocial well-being of adolescents and young adults. OHIP-TMDs, preferably appraised by severity, extent and prevalence, was able to discriminate between subjects with and without TMDs. It holds promise as a TMDs-specific OHRQoL instrument for epidemiological studies.
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Calidad de Vida , Trastornos de la Articulación Temporomandibular , Adolescente , Adulto , Femenino , Humanos , Masculino , Salud Bucal , Prevalencia , Encuestas y Cuestionarios , Adulto JovenRESUMEN
This study investigated the color (ΔE) and translucency changes (ΔTP) of CAD/CAM composites after exposure to staining solutions using both spectrophotometer and shade-matching device. Direct (Filtek Z350XT [ZT]), indirect (Shofu Ceramage [CE]) and CAD/CAM (Shofu HC Block [HC], Lava Ultimate [LU], Vita Enamic [EN]) composite specimens measuring 12 × 14 × 1.5 mm were fabricated, divided into five groups (n = 8), and immersed in cola, tea, coffee, red wine, distilled water (control) at 37°C for 7 days. Color parameters were determined with both spectrophotometer and shade-taking device at baseline and 1 week. Delta E (ΔE) with white and black backgrounds, and Delta TP (ΔTP) were computed. Statistical testing was performed with ANOVA and Tukey post hoc test (P < .05). Mean ΔE (white) values ranged from 0.20 ± 0.06 to 12.26 ± 1.95 while mean ΔE (black) varied from 0.22 ± 0.11 to 14.21 ± 2.37. Mean ΔTP values ranged from 0.13 ± 0.17 to -3.87 ± 2.16. CAD/CAM composites fared better in red wine than direct and indirect materials. Clinically perceptible color changes (ΔE > 3.3) were observed for almost all materials when exposed to wine, coffee and tea. Direct, indirect, and CAD/CAM composites are all susceptible to various degrees of discoloration and translucency changes after exposure to staining beverages. Red wine caused the most discoloration and translucency changes. Limitations of these materials must be considered when placing an aesthetic restoration. CLINICAL SIGNIFICANCE: Direct, indirect, and CAD/CAM composites are all susceptible to various degrees of discoloration and translucency changes after exposure to staining beverages. Red wine generally caused the most discoloration and translucency changes. Although CAD/CAM composites were more color stable than direct and indirect materials when exposed to red wine, color changes were still clinically perceptible.
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Resinas Compuestas , Té , Bebidas , Color , Ensayo de Materiales , Espectrofotometría , Coloración y Etiquetado , Propiedades de SuperficieRESUMEN
Anterior repositioning splints (ARS) are used primarily for the management of temporomandibular joint (TMJ) anterior disc displacement with reduction (ADDwR). However, the exact physiological effects of ARS are still unclear. This study investigated the short and long-term effects of ARS on disc and condyle angles/positions by metric analysis. Twenty-two subjects diagnosed with ADDwR were recruited. Maxillary full-coverage ARS were fabricated, and MRI of TMJs was obtained before splint treatment, immediate post-insertion and 6 months after splint treatment. Disc-condyle relationship was determined by disc-condyle angle measurement. Disc and condyle positions were described as X-Y coordinates with the summit of glenoid fossa as the origin of the coordinates. Thirty-two TMJs were classified as ADDwR and 12 were normal. Upon ARS insertion, all TMJs with ADDwR got normal disc-condyle relationships. The condyles moved significantly forward and downward, while the discs moved significantly backward and upward. MRI at 6 months after treatment (without ARS insertion) indicated that only 40·6% (13/32) of the joints were maintained in the normal disc-condyle relationship. The majority of condyles returned to their pre-treatment positions, while the discs generally moved anteriorly again. The use of ARS resulted in forward and downward condyle movement, and a concurrent backward movement of the disc resulting in ideal spatial disc-condyle relationship. The stability of this relationship, however, could not be maintained in the majority of TMJs upon ARS removal. Findings explain the good short-term clinical outcomes with ARS and their relatively lower efficacy in the long term.
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Luxaciones Articulares/fisiopatología , Imagen por Resonancia Magnética , Cóndilo Mandibular/fisiopatología , Ferulas Oclusales , Ortodoncia Correctiva , Disco de la Articulación Temporomandibular/fisiopatología , Trastornos de la Articulación Temporomandibular/fisiopatología , Adolescente , Adulto , Análisis de Varianza , Estudios de Evaluación como Asunto , Femenino , Humanos , Luxaciones Articulares/diagnóstico por imagen , Luxaciones Articulares/terapia , Masculino , Cóndilo Mandibular/diagnóstico por imagen , Propiocepción/fisiología , Valores de Referencia , Reproducibilidad de los Resultados , Disco de la Articulación Temporomandibular/diagnóstico por imagen , Trastornos de la Articulación Temporomandibular/diagnóstico por imagen , Trastornos de la Articulación Temporomandibular/terapia , Resultado del Tratamiento , Adulto JovenRESUMEN
This study examined the influence of cariogenic environments on the surface roughness of ion-releasing restorative materials (IRMs). Custom-made stainless steel molds with holes of 5 mm × 2mm were used to fabricate 60 disc-shaped specimens of each of the following materials: Activa Bioactive (AV), Beautifil Bulk Restorative (BB), Cention N (Bulk-fill) (CN), and Filtek Z350XT (FZ) (Control). Baseline surface roughness (Ra) measurements were obtained using an optical 3D measurement machine (Alicona Imaging GmbH, Graz, Austria). The specimens were then randomly divided into five subgroups (n=12) and exposed to 10 ml of the following mediums at 37°C: distilled water (DW), demineralization solution (DM), remineralization solution (RM), pH cycling (PC) and air (AR) (control). Ra measurements were again recorded after one week and one month, followed by statistical evaluations with two-way analysis of variance (ANOVA) to determine interactions between materials and mediums. One-way ANOVA and post hoc Games Howell tests were performed for intergroup comparisons at a significance level of 0.05. Mean Ra values ranged from 0.085 ± 0.004 (µm) to 0.198 ± 0.001 µm for the various material-medium combinations. All IRMs showed significant differences in Ra values after exposure to the aqueous mediums. The smoothest surfaces were observed in the AR for all materials. When comparing materials, AV presented the roughest surfaces for all mediums. All IRM materials showed increased surface roughness over time in all cariogenic environments but were below the threshold value for bacterial adhesion, except for AV 1-month post immersion with pH cycling. Therefore, besides AV, the surface roughness of IRMs did not deteriorate to an extent that it is clinically relevant.
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Resinas Compuestas , Materiales Dentales , Resinas Compuestas/uso terapéutico , Ensayo de Materiales , Agua , Adhesión Bacteriana , Propiedades de SuperficieRESUMEN
This study investigated the effects of environmental pH on the flexural properties of ion-releasing restorative materials (IRMs), including giomer (Beautifil-Bulk Restorative - BB), alkasite (Cention N - CN), bioactive composite (Activa - AB) and resin-modified glass ionomer (Riva Light Cure -RV) restoratives. A bio-inert resin-based composite (Filtek Bulk-fill Posterior - FB) served as the control. Stainless steel molds were used to fabricate 40 beam-shaped specimens (12mm × 2mm × 2mm) for each material. The specimens were finished, measured, and randomly distributed into four groups (n=10) and immersed in aqueous solutions of pH 3.0, pH 5.0, pH 6.8, and pH 10.0 at 37°C for 28 days. Specimens were then subjected to a uniaxial three-point bending flexural test with a load cell of 5 KN and a fixed deformation rate of 0.5 mm/min until fracture occurred. Flexural modulus and strength were statistically analyzed using analysis of variance/Dunnet T3's test (p=0.05). Mean flexural modulus varied from (2.40±0.41 to 9.65±1.21 GPa), while mean flexural strength ranged from (21.56±2.78 to 163.86±13.13 MPa). Significant differences in flexural properties were observed among the various pH values and materials. All materials immersed in artificial saliva (pH 6.8) presented the highest flexural properties, except AB. The flexural strength of AB was significantly better when exposed to acidic environments. FB had better flexural properties than IRMs after exposure to a range of environmental pH values.
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Resinas Compuestas , Resistencia Flexional , Ensayo de Materiales , Resinas Compuestas/química , Materiales Dentales , Agua , Concentración de Iones de Hidrógeno , Propiedades de SuperficieRESUMEN
AIM: To synthesise knowledge on the relative efficacies of non-pharmacological strategies for managing dental fear and anxiety (DFA) in children and adolescents, specifically their effects on behaviour, anxiety levels and pain perception. METHODS: An umbrella review on non-pharmacological strategies used to manage DFA in children and adolescents was conducted based the Joanna Briggs Institute methodology. Searches were performed in 5 main electronic databases and the grey-literature. Two independent reviewers selected and appraised the included studies using the AMSTAR2 tool. Disagreements were resolved by a third reviewer. CONCLUSION: Audio-visual distraction was effective in reducing anxiety during a variety of dental procedures including those requiring local anaesthesia. A combination of techniques may be more effective in managing DFA in children and adolescents, possibly improving pain perception and cooperative behaviour.
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Ansiedad al Tratamiento Odontológico , Adolescente , Niño , Ansiedad al Tratamiento Odontológico/prevención & control , HumanosRESUMEN
OBJECTIVES: This study determined the effects of self-adhesive resin coatings on viscoelastic properties of highly viscous glass ionomer cements (HVGICs) using dynamic mechanical analysis. MATERIALS AND METHODS: The HVGICs evaluated were Zirconomer [ZR] (Shofu), Equia Forte [EQ] (GC) and Riva [RV] (SDI). Sixty specimens (12mm x 2mm x 2mm) of each material were fabricated using customized Teflon molds. After initial set, the specimens were removed from their molds, finished, measured and randomly divided into 3 groups of 20. Half the specimens in each group were left uncoated while the remaining half was covered with the respective manufacturers' resin coating. The specimens were subsequently conditioned in distilled water, artificial saliva or citric acid at 37°C for 7 days. The uncoated and coated specimens (n=10) were then subjected to dynamic mechanical testing in flexure mode at 37°C with a frequency of 0.1 to 10Hz. Storage modulus, loss modulus and loss tangent data were subjected to normality testing and statistical analysis using one-way ANOVA/Scheffe's post-hoc test and Ttest at significance level p<0.05. RESULTS: Mean storage modulus ranged from 1.39 ± 0.36 to 10.80 ± 0.86 GPa while mean loss modulus varied from 0.13 ± 0.03 to 0.70 ± 0.14 GPa after conditioning in the different mediums. Values for loss tangent ranged from 39.4 ± 7.75 to 213.2 ± 20.11 (x10 -3 ). Significant differences in visco-elastic properties were observed between mediums and materials. When conditioned in distilled water and artificial saliva,storage modulus was significantly improved when ZR, EQ and RV were uncoated. Significantly higher values were, however, observed with resin coating when the materials were exposed to citric acid. CONCLUSION: The visco-elastic properties of HVGICs were influenced by both resin coating and chemical environment.
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Cementos de Ionómero Vítreo , Agua , Resinas Compuestas , Ensayo de Materiales , Cementos de Resina , Saliva Artificial , ViscosidadRESUMEN
This study determined the mechanical performance of bioactive restoratives in cariogenic environments and compared the flexural properties of various bioactive materials. The materials evaluated included a conventional resin-based composite (Filtek Z350 [FZ]) and 3 bioactive restoratives, namely an alkasite (Cention N [CN]), a giomer (Beautifil-bulk Restorative [BB]), and an enhanced resin-modified glass ionomer (Activa Bioactive Restorative [AV]). Beam-shaped specimens (12 x 2 x 2 mm) were produced, randomly allocated to 4 groups (n=10), and conditioned in deionized solution, remineralizing solution, demineralizing solution (DE), or pH cycled for 14 days at 37°C. After conditioning/pH cycling, the specimens were subjected to 3-point flexural testing. Flexural data were subjected to statistical analysis using analysis of variance or Tukey's test (α=0.05). Mean flexural modulus and strength ranged from 3.54 ± 0.33 to 7.44 ± 0.28 GPa, and 87.07 ± 8.99 to 123.54 ± 12.37 MPa, respectively. While the flexural modulus of the bioactive restoratives was not affected by cariogenic/acidic conditions, flexural strength usually decreased, with the exception of CN. The strength of BB was significantly reduced by DE and pH cycling, while that of AV was lowered by DE. For all conditioning mediums, AV had a significantly lower modulus than the other materials. Apart from conditioning in DE, where differences in flexural strength was insignificant, FZ and AV were generally significantly stronger than BB and CN. The effect of cariogenic environments on flexural strength was found to be material dependent, and aside from the alkasite material (CN), cariogenic conditions were observed to significantly decrease the strength of bioactive restoratives.
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Resinas Compuestas , Resistencia Flexional , Materiales Dentales , Ensayo de Materiales , DocilidadRESUMEN
The objectives of the study were to compare the flexural modulus and strength of restorative and flowable bulk-fill resin-based composites (RBCs) to their conventional counterparts and to determine the effects of conditioning environment on their flexural properties. The materials evaluated included three conventional RBCs (Filtek Z350, Tetric N Ceram, and Beautifil II), three restorative bulk-fill RBCs (Filtek Bulk-Fill Restorative, Tetric N Ceram Bulk-Fill, and Beautifil Bulk-fill Restorative), as well as three flowable bulk-fill RBCs (Filtek Bulk-Fill Flowable, Tetric N Flow Bulk-Fill, and Beautifil Bulk-Fill Flowable). Specimens were fabricated using customized stainless-steel molds, finished, measured, and randomly divided into four groups. The various RBCs were conditioned in the following mediums (n=10) for seven days at 37°C: air, artificial saliva (SAGF), 0.02 N citric acid, and 50% ethanol-water solution. After conditioning, the specimens were rinsed, blotted dry, measured, and subjected to flexural testing using a universal testing machine. Data were subjected to statistical analysis using analysis of variance and the Tukey test at a significance level of α = 0.05. Significant differences in flexural properties were observed between materials and conditioning mediums. Bulk-fill restorative RBCs exhibited higher flexural modulus than their bulk-fill flowable and conventional counterparts. With the exception of Filtek Bulk-Fill Flowable, bulk-fill flowable RBCs had significantly higher flexural strength than bulk-fill restorative and conventional RBCs. Flexural properties were highest when RBCs were conditioned in air and generally the lowest after exposure to ethanol.
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Resinas Compuestas , Resistencia Flexional , Materiales Dentales , Análisis del Estrés Dental , Ensayo de MaterialesRESUMEN
This study compared the viscoelastic properties of restorative and flowable bulk-fill resin-based composites (RBCs) with their conventional counterparts and evaluated the impact of aqueous solutions on viscoelastic properties. The materials examined included three conventional RBCs (Filtek Z350, Tetric N Ceram, and Beautifil II), three restorative bulk-fill RBCs (Filtek Bulk-Fill Restorative, Tetric N Ceram Bulk-Fill, and Beautifil Bulk-Fill Restorative) in addition to three flowable bulk-fill RBCs (Filtek Bulk-Fill Flowable, Tetric N Flow Bulk-Fill, and Beautifil Bulk-Fill Flowable). Beam-shaped specimens (12×2×2 mm) were fabricated using customized stainless-steel molds, finished, and measured. The specimens were randomly divided into four groups and conditioned in air (control), artificial saliva, 0.02 N citric acid, and 50% ethanol-water solution for seven days at 37°C. They were then subjected to dynamic mechanical analysis (n = 10) in flexure mode at 37°C with a frequency of 0.1 to 10 Hz. Storage modulus, loss modulus, and loss tangent data were subjected to statistical analysis using one-way analysis of variance/Tukey post hoc test at a significance level of α = 0.05. Viscoelastic properties of the RBCs were found to be product and conditioning medium dependent. For most RBCs, exposure to aqueous solutions, particularly an ethanol-water solution, degraded viscoelastic properties. With the exception of Filtek Bulk-Fill Restorative, bulk-fill restorative and flowable RBCs generally had significantly lower storage and loss modulus than their conventional counterparts regardless of conditioning medium. Conventional RBCs are thus favored over their bulk-fill counterparts, particularly for high-stress-bearing areas.
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Resinas Compuestas , Materiales Dentales , Ensayo de Materiales , Saliva ArtificialRESUMEN
This study investigated the efficacy of a sequential combination of arthrocentesis, mandibular manipulation, and anterior repositioning splint (ARS) in the management of acute temporomandibular joint (TMJ) disc displacement without reduction (DDwoR). Twenty-one consecutive patients diagnosed with acute DDwoR by Diagnostic Criteria for Temporomandibular Disorders and magnetic resonance imaging (MRI) were recruited and managed with this method. Clinical and MRI data were obtained before and at 1 week after treatment. The disc-condyle relationship was determined by disc-condyle angle measurement. Condyle/disc positions were described as x-y coordinates with the summit of the articular fossa as the coordinate origin. Statistical analyses including independent/paired samples t-tests were conducted; significance was set at P<0.05. Clinical success was observed in 95.2% of patients (20/21) with 22 joints affected by acute DDwoR. After combined treatment and ARS insertion, TMJs with DDwoR showed (a) normal disc-condyle relationships with substantial forward and downward condyle movement and significant disc reduction in closed position, and (b) discs with an intermediate zone located between the condylar head and articular eminence in open position. The combined approach was highly effective in 'unlocking' acute TMJ DDwoR and achieving spatial full disc reduction and a normal disc-condyle relationship. The duration of acute DDwoR appears to be critical for success.
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Luxaciones Articulares , Disco de la Articulación Temporomandibular , Protocolos Clínicos , Humanos , Imagen por Resonancia Magnética , Cóndilo MandibularRESUMEN
CLINICAL RELEVANCE: Computer-aided design/computer-aided manufacturing (CAD/CAM) composite resins are susceptible to degradation by dietary solvents. Dietary counselling is prudent when placing such CAD/CAM restorations. SUMMARY: This study determined the effect of dietary solvents on the surface roughness (Ra) of direct, indirect, and computer-aided design/computer-aided manufacturing (CAD/CAM) dental composites. The materials evaluated were a direct composite (Filtek Z350 XT [FZ]), an indirect composite (Shofu Ceramage [CM]), and four CAD/CAM composites (Lava Ultimate [LU], Shofu Block HC [HC], Cerasmart [CS], and Vita Enamic [VE]). Specimens (12×14×1.5 mm) of each material were prepared, measured for baseline Ra, ranked, divided into six groups (n=12), and conditioned in the following media for 1 week at 37°C: air (control), distilled water, 0.02 N citric acid, 0.02 N lactic acid, heptane, and 50% ethanol-water solution. The composite specimens were then subjected to postconditioning Ra testing using an optical three-dimensional surface analyzer (G4e, Alicona Imaging GmbH, Raaba, Austria). Inter-medium and inter-material comparisons were performed with one-way analysis of variance and post hoc Bonferroni test at a significance level of α=0.05. Mean Ra values ranged from 0.086 ± 0.004 µm to 0.153 ± 0.005 µm for the various material/medium combinations. For all materials, conditioning in air (control) and distilled water generally resulted in significantly lower mean Ra than exposure to other dietary solvents. Conditioning in citric acid presented the roughest surfaces for FZ, CM, and CS. For LU, HC, and VE, exposure to lactic acid, heptane, and ethanol solution resulted in the highest mean Ra. Regardless of conditioning media, FZ had the highest and VE the lowest mean Ra compared with other composites. The CAD/CAM composites remained susceptible to surface degradation by dietary solvents despite their industrial polymerization.
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Resinas Compuestas , Diseño Asistido por Computadora , Cerámica , Ensayo de Materiales , Solventes , Propiedades de SuperficieRESUMEN
This study investigated the association between hypoplastic condyles and disc displacements without reduction (DDw/oR). Consecutive patients with non-syndromic unilateral condylar hypoplasia were recruited and clinical, cone beam computed tomography (CBCT) and magnetic resonance imaging (MRI) data were acquired. Linear measurements including condylar head width, depth, height and condyle length were determined with CBCT while MRI was used to assess disc position, morphology and displacement. A total of 43 patients were enrolled of which 93.02% had a history of temporomandibular disorders (TMDs) and 83.72% presented with TMD signs and symptoms. Depth and height of the condylar head along with condyle length of hypoplastic joints (6.68±1.67mm, 4.97±1.25mm and 14.49±3.02mm, respectively) were significantly lesser than normal joints (7.77±1.26mm, 6.35±1.45mm and 18.20±3.18mm) (P<0.001). The prevalence of DDw/oR was significantly higher in hypoplastic joints (79.07% versus 13.95%) (P<0.001). Joints with hypoplastic condyles had shorter disc lengths (6.99 ± 2.16 mm vs, 8.45 ± 2.26 mm) (P=0.007). Furthermore, disc displacements were significantly more advanced (8.52 ± 2.84 mm) and severe (76.74% with severe translations) when compared to the contralateral side (4.77 ± 2.97 mm and 32.56%) (P<0.05). A significant association was observed between condylar hypoplasia and temporomandibular joint DDw/oR with hypoplastic joints exhibiting more severely displaced and deformed discs. DDw/oR coupled with repaired degenerative joint disease may mimic condylar hypoplasia radiographically.
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Luxaciones Articulares , Trastornos de la Articulación Temporomandibular , Tomografía Computarizada de Haz Cónico , Humanos , Imagen por Resonancia Magnética , Cóndilo Mandibular , Articulación Temporomandibular , Disco de la Articulación TemporomandibularRESUMEN
This study determined the influence of shrinkage and viscosity of flowable composite liners on the cervical microleakage of Class II restorations using micro-CT. Seven composites of varying viscosities were selected and included five giomers (Shofu Beautifil II [BF], Flow Plus F00 and F03 [F00 and F03], Flow F02 and F10 [F02 and F10]) and 2 nano-filled composites (3M-ESPE Filtek Z350 [Z350] and Filtek Z350 Flowable [Z350F]). Polymerization shrinkage (n=7) was assessed with the Acuvol volumetric shrinkage analyzer while complex viscosity was determined with the advanced rheometric expansion system at 25°C. Standardized Class II restorations incorporating 1-mm horizontal layers of different flowable liners and 3-mm oblique layers of BF or Z350 were subjected to a silver nitrate test for 24 hours and examined using micro-CT. Microleakage was determined at 0.1-mm intervals from the buccal to lingual surfaces providing 30 sites per specimen and scored accordingly. Statistical analysis was performed with the one-way ANOVA, Kruskal-Wallis test, and Spearman's rho correlation at a significance level of p<0.05. Mean volumetric shrinkage ranged from 5.33±0.17% to 2.35±0.02% for F02 to Z350, respectively. The flowable materials had significantly higher shrinkage than did their sculptable counterparts (BF and Z350). Complex viscosities ranged from 9.65 to 4.20 (Z350 and F10, respectively) at a frequency of 10 rad/s and from 8.16 to 3.28 (Z350 and F03, respectively) for 100 rad/s. Giomer restorations had significantly less leakage than did those restored with nano-filled composites. No microleakage was observed with restorations lined with F02 or F10. The use of flowable liners reduced cervical microleakage of Class II restorations. Interfacial integrity of Class II restorations was significantly correlated with liner viscosity, filler volume, and shrinkage.
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Resinas Compuestas/química , Recubrimiento de la Cavidad Dental/instrumentación , Preparación de la Cavidad Dental/métodos , Filtración Dental , Microtomografía por Rayos X , Diente Premolar , Bisfenol A Glicidil Metacrilato , Restauración Dental Permanente/métodos , Humanos , Técnicas In Vitro , Ensayo de Materiales , Polimerizacion , ViscosidadRESUMEN
The objective of this study was to determine the influence of specimen dimension and conditioning medium on the dynamic and static flexural properties of resin-based composites (RBCs). One conventional (Filtek Z350) and two bulk-fill RBCs (Filtek Bulk-fill and Beautifil-Bulk Restorative) were evaluated. Bar-shaped specimens with dimensions 25 × 2 × 2 mm (ISO flexural [IFT]) or 12 × 2 × 2 mm (mini-flexural [MFT]) were fabricated using customized stainless-steel molds, finished, measured, randomly divided into two groups, and conditioned in air or artificial saliva (SAGF) for seven days at 37°C. The specimens (n=10) were then subjected to dynamic and static three-point flexural testing. Data for storage modulus, loss modulus, loss tangent, flexural strength, and modulus were computed and subjected to t-test, analysis of variance/Tukey test, and Pearson correlation at a significance level of α = 0.05. For both IFT and MFT, significant differences in dynamic and static flexural properties were more prevalent between materials after storage in saliva. For both conditioning mediums, the strongest correlation between IFT and MFT was observed for flexural strength. While significant positive correlations were observed for all flexural properties with saliva, no significant correlations were detected for loss tangent and flexural modulus with air. For both IFT and MFT, storage in saliva appeared to be more discriminative than storage in air. As moderate to strong positive relationships exist between IFT and MFT for dynamic and static flexural properties, the mini-flexural test holds promise as a replacement for the ISO 4049 in view of its clinical relevance and greater efficiency.
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Resinas Compuestas/normas , Bisfenol A Glicidil Metacrilato/normas , Análisis del Estrés Dental/métodos , Resistencia Flexional , HumanosRESUMEN
This study compared the effectiveness of cure of bulk-fill composites using polywave light-emitting diode (LED; with various curing modes), monowave LED, and conventional halogen curing lights. The bulk-fill composites evaluated were Tetric N-Ceram bulk-fill (TNC), which contained a novel germanium photoinitiator (Ivocerin), and Smart Dentin Replacement (SDR). The composites were placed into black polyvinyl molds with cylindrical recesses of 4-mm height and 3-mm diameter and photopolymerized as follows: Bluephase N Polywave High (NH), 1200 mW/cm2 (10 seconds); Bluephase N Polywave Low (NL), 650 mW/cm2 (18.5 seconds); Bluephase N Polywave soft-start (NS), 0-650 mW/cm2 (5 seconds) â 1200 mW/cm2 (10 seconds); Bluephase N Monowave (NM), 800 mW/cm2 (15 seconds); QHL75 (QH), 550 mW/cm2 (21.8 seconds). Total energy output was fixed at 12,000 mJ/cm2 for all lights/modes, with the exception of NS. The cured specimens were stored in a light-proof container at 37°C for 24 hours, and hardness (Knoop Hardness Number) of the top and bottom surfaces of the specimens was determined using a Knoop microhardness tester (n=6). Hardness data and bottom-to-top hardness ratios were subjected to statistical analysis using one-way analysis of variance/Scheffe's post hoc test at a significance level of 0.05. Hardness ratios ranged from 38.43% ± 5.19% to 49.25% ± 6.38% for TNC and 50.67% ± 1.54% to 67.62% ± 6.96% for SDR. For both bulk-fill composites, the highest hardness ratios were obtained with NM and lowest hardness ratios with NL. While no significant difference in hardness ratios was observed between curing lights/modes for TNC, the hardness ratio obtained with NM was significantly higher than the hardness ratio obtained for NL for SDR.
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Luces de Curación Dental , Materiales Dentales/química , Curación por Luz de Adhesivos Dentales/instrumentación , Resinas Compuestas , Dureza , Ensayo de Materiales , Polimerizacion , Propiedades de SuperficieRESUMEN
This study investigated the viscoelastic properties of contemporary bulk-fill restoratives in distilled water and artificial saliva using dynamic mechanical analysis. The materials evaluated included a conventional composite (Filtek Z350), two bulk-fill composites (Filtek Bulk-fill and Tetric N Ceram), a bulk-fill giomer (Beautifil-Bulk Restorative), and two novel reinforced glass ionomer cements (Zirconomer [ZR] and Equia Forte [EQ]). The glass ionomer materials were also assessed with and without resin coating (Equia Forte Coat). Test specimens 12 × 2 × 2 mm of the various materials were fabricated using customized stainless-steel molds. After light polymerization/initial set, the specimens were removed from the molds, finished, measured, and conditioned in distilled water or artificial saliva at 37°C for seven days. The materials (n=10) were then subjected to dynamic mechanical testing in flexure mode at 37°C and a frequency of 0.1 to 10 Hz. Storage modulus, loss modulus, and loss tangent data were subjected to normality testing and statistical analysis using one-way analysis of variance/Dunnett's test and t-test at a significance level of p < 0.05. Mean storage modulus ranged from 3.16 ± 0.25 to 8.98 ± 0.44 GPa, while mean loss modulus ranged from 0.24 ± 0.03 to 0.65 ± 0.12 GPa for distilled water and artificial saliva. Values for loss tangent ranged from 45.7 ± 7.33 to 134.2 ± 12.36 (10-3). Significant differences in storage/loss modulus and loss tangent were observed between the various bulk-fill restoratives and two conditioning mediums. Storage modulus was significantly improved when EQ and ZR was not coated with resin.
Asunto(s)
Bisfenol A Glicidil Metacrilato/química , Resinas Compuestas/química , Cementos de Ionómero Vítreo/química , Análisis del Estrés Dental , Elasticidad , ViscosidadRESUMEN
Glass ionomer cements (GICs) are a class of bioactive cements that bond directly to bone. In this paper, a new bioactive hydroxyapatite (HA)/zirconia (ZrO(2))-filled GIC composite was developed to improve the biocompatibility and bioactivity of the GICs with the surrounding bone and connective tissues. Nano-sized HA/30 wt% ZrO(2) powders were heat treated at 700 degrees Celsius and 800 degrees Celsius for 3 h to elucidate the influence of the crystallinity of composite powders on the performance of HA/ZrO(2)-GICs. The effects of different volume percentages of HA/ZrO(2) powders (4, 12, 28 and 40 vol%) substituted within GICs were investigated based on their microhardness, compressive strength and diametral tensile strength. The HA/ZrO(2)-GICs composite was soaked in distilled water for 1 day and 1 week before subjecting the samples to mechanical testing. Results showed that the glass and HA/ZrO(2) particles were distributed uniformly in the GIC matrix. The substitution of highly crystalline HA/ZrO(2) improved the mechanical properties of the HA/ZrO(2)-GICs due to the slow resorption rate for highly crystalline powders in distilled water. The mechanical properties of HA/ZrO(2)-GICs increased with increasing soak time due to the continuous formation of aluminium salt bridges, which improved the final strength of the cements. The compositions 4 and 12 vol% HA/ZrO(2)-GICs exhibited superior mechanical properties than the original GICs. The mechanical properties of HA/ZrO(2)-GICs were found to be much better than those of HA-GICs because ZrO(2) has the attributes of high strength, high modulus, and is significantly harder than glass and HA particles. Furthermore, ZrO(2) does not dissolve with increasing soaking time.
Asunto(s)
Cementos para Huesos/química , Durapatita/química , Cementos de Ionómero Vítreo/química , Circonio/química , Cementos para Huesos/síntesis química , Fuerza Compresiva , Dureza , Ensayo de Materiales , Tamaño de la Partícula , Polvos , Propiedades de Superficie , Resistencia a la TracciónRESUMEN
Bleaching of teeth is gaining popularity due to cosmetic reasons. However, the effect it has on teeth is still largely unknown. This paper seeks to evaluate the effect of a bleaching agent, 30% hydrogen peroxide, on the nanomechanical properties of dentin and enamel using the nanoindentation technique. The Young's modulus and hardness obtained from nanoindentation before and after bleaching were compared. Five newly extracted human premolars were used. Nanoindentation was first done on the sliced enamel and dentin regions to determine their mechanical properties. One batch of samples was kept in Hank's balanced salt solution as control while the other was bleached in 30% hydrogen peroxide for 24h. The same number of nanoindentations was then done near the previously indented regions for both the control and bleached samples and the results compared. Using paired sample t-tests with alpha=0.05, it was found that there were no significant differences in both the Young's modulus and hardness of dentin and enamel kept in control. However, the mechanical properties of the bleached dentin were significantly decreased. For intertubular dentin, the mean hardness decreased by 29-55% and the mean Young's modulus decreased by 19-43%. For enamel, the mean hardness decreased by 13-32% while the mean Young's modulus decreased by 18-32%. The exact mechanism by which hydrogen peroxide affects the dentin and enamel has yet to be fully elucidated. However, it is observed to have an undermining effect on the nanomechanical properties of teeth.