RESUMEN
AIM: To investigate the effect of medicaments used in endodontic regeneration on root fracture resistance and microhardness of radicular dentine. METHODOLOGY: The root canals of mandibular premolars (n = 180) were instrumented and randomized into three treatment groups and an untreated control group. Each treatment group received either triple antibiotic paste (TAP), double antibiotic paste (DAP) or calcium hydroxide paste [Ca(OH)2] intracanal medicament. Teeth were kept in saline for 1 week, 1 month or 3 months. After each time-point, 15 teeth were randomly selected from each group and two root cylinders were obtained from each tooth. One cylinder was subjected to a fracture resistance test, and the other cylinder was used for a microhardness test. Two-way ANOVA and Tukey's pairwise comparisons were used for statistical analysis. RESULTS: For the microhardness test, the two-way interaction between group and time was significant (P < 0.001). The intracanal application of TAP and DAP caused significant and continuous decrease in root dentine microhardness after one (P < 0.05) and 3 months (P < 0.001), respectively. The three-month intracanal application of Ca(OH)2 significantly increased the microhardness of root dentine (P < 0.05). The time factor had a significant effect on fracture resistance (P < 0.001). The three intracanal medicaments caused significant decreases in fracture resistance ranging between 19% and 30% after 3-month application compared to 1-week application. CONCLUSION: In this laboratory study, the 3-month application of triple antibiotic paste, double antibiotic paste or calcium hydroxide paste medicaments significantly reduced the root fracture resistance of extracted teeth compared to a 1-week application.
Asunto(s)
Apexificación/métodos , Dentina/efectos de los fármacos , Irrigantes del Conducto Radicular/uso terapéutico , Fracturas de los Dientes/fisiopatología , Raíz del Diente/efectos de los fármacos , Antibacterianos/administración & dosificación , Diente Premolar/efectos de los fármacos , Hidróxido de Calcio/uso terapéutico , Ciprofloxacina/administración & dosificación , Dentina/ultraestructura , Combinación de Medicamentos , Dureza , Humanos , Ensayo de Materiales , Metronidazol/administración & dosificación , Microscopía Electrónica de Rastreo , Minociclina/administración & dosificación , Preparación del Conducto Radicular/métodos , Capa de Barro Dentinario , Factores de Tiempo , Raíz del Diente/lesiones , Raíz del Diente/ultraestructuraRESUMEN
The aim of this review was to identify and analyse all studies related to the effect of nonsetting calcium hydroxide [Ca(OH)(2)] on root fracture and various mechanical properties of radicular dentine. A PubMed search was conducted using the keywords 'calcium hydroxide' and 'dentistry' combined with MeSH terms 'tooth fractures' or 'mechanical phenomena' or 'compressive strength'. The search was expanded by including Embase and Web of Science databases, using the keywords 'calcium hydroxide' and 'root' and 'fracture'. The search was supplemented by checking the reference lists from each selected article. Each study had to meet the following criteria to be selected for review: (i) Inclusion of at least one experimental group with root or radicular dentine either filled with or exposed to nonsetting Ca(OH)(2); (ii) inclusion of at least one appropriate control group; and (iii) a minimum of five samples per experimental group. Only articles written in English were included. Of the 16 studies selected initially, 12 in vitro studies fulfilled the selection criteria for inclusion in the final review. No clinical studies that directly supported the correlation between Ca(OH)(2) intracanal dressing and root fracture were found in the literature. However, the majority of in vitro studies showed reduction in the mechanical properties of radicular dentine after exposure to Ca(OH)(2) for 5 weeks or longer. Conversely, the data were inconclusive regarding whether Ca(OH)(2) exposure for 1 month or less had a negative effect on the mechanical properties of radicular dentine.
Asunto(s)
Hidróxido de Calcio/efectos adversos , Dentina/efectos de los fármacos , Materiales de Obturación del Conducto Radicular/efectos adversos , Fracturas de los Dientes/etiología , Raíz del Diente/efectos de los fármacos , Animales , Bovinos , Fuerza Compresiva/efectos de los fármacos , Análisis del Estrés Dental , Módulo de Elasticidad/efectos de los fármacos , Dureza/efectos de los fármacos , Humanos , OvinosRESUMEN
OBJECTIVE: This laboratory study compared the repaired microtensile bond strengths of aged silorane resin composite using different surface treatments and either silorane or methacrylate resin composite. METHODS: One hundred eight silorane resin composite blocks (Filtek LS) were fabricated and aged by thermocycling between 8°C and 48°C (5000 cycles). A control (solid resin composite) and four surface treatment groups (no treatment, acid treatment, aluminum oxide sandblasting, and diamond bur abrasion) were tested (N=12 blocks, 108 beams/group). Each treatment group was randomly divided in half and repaired with either silorane resin composite (LS adhesive) or methacrylate resin composite (Filtek Z250/Single Bond Plus). After 24 hours in 37°C distilled water, microtensile bond strength testing was performed using a non-trimming technique. Surface topography after surface treatment was analyzed using scanning electron microscopy (SEM). Failure mode was examined using optical microscopy (50×). RESULTS: Weibull-distribution survival analysis revealed that aluminum oxide sandblasting followed by silorane or methacrylate resin composite and acid treatment with methacrylate resin composite provided insignificant differences from the control (p>0.05). All other groups were significantly lower than the control. Failure was primarily adhesive in all groups. CONCLUSION: Aluminum oxide sandblasting produced microtensile bond strength not different from the cohesive strength of silorane resin composite. After aluminum oxide sandblasting, aged silorane resin composite can be repaired with either silorane resin composite with LS system adhesive or methacrylate resin composite with methacrylate dental adhesive.
Asunto(s)
Resinas Compuestas/química , Recubrimiento Dental Adhesivo , Materiales Dentales/química , Resinas de Silorano/química , Grabado Ácido Dental/métodos , Adhesividad , Óxido de Aluminio/química , Bisfenol A Glicidil Metacrilato/química , Grabado Dental/métodos , Reparación de Restauración Dental , Análisis del Estrés Dental/instrumentación , Diamante/química , Humanos , Ensayo de Materiales , Metacrilatos/química , Microscopía Electrónica de Rastreo , Ácidos Fosfóricos/química , Estrés Mecánico , Propiedades de Superficie , Temperatura , Resistencia a la Tracción , Factores de Tiempo , Agua/químicaRESUMEN
UNLABELLED: Aged resin composites have a limited number of carbon-carbon double bonds to adhere to a new layer of resin. Study objectives were to 1) evaluate various surface treatments on repaired shear bond strength between aged and new resin composites and 2) to assess the influence of a silane coupling agent after surface treatments. METHODS: Eighty disk-shape resin composite specimens were fabricated and thermocycled 5000 times prior to surface treatment. Specimens were randomly assigned to one of the three surface treatment groups (n=20): 1) air abrasion with 50-µm aluminum oxide, 2) tribochemical silica coating (CoJet), or 3) Er,Cr:YSGG (erbium, chromium: yttrium-scandium-gallium-garnet) laser or to a no-treatment control group (n=20). Specimens were etched with 35% phosphoric acid, rinsed, and dried. Each group was divided into two subgroups (n=10): A) no silanization and B) with silanization. The adhesive agent was applied and new resin composite was bonded to each conditioned surface. Shear bond strength was evaluated and data analyzed using two-way analysis of variance (ANOVA). RESULTS: Air abrasion with 50-µm aluminum oxide showed significantly higher repair bond strength than the Er,Cr:YSGG laser and control groups. Air abrasion with 50-µm aluminum oxide was not significantly different from tribochemical silica coating. Tribochemical silica coating had significantly higher repair bond strength than Er,Cr:YSGG laser and the control. Er,Cr:YSGG laser and the control did not have significantly different repair bond strengths. Silanization had no influence on repair bond strength for any of the surface treatment methods. CONCLUSION: Air abrasion with 50-µm aluminum oxide and tribochemical silica followed by the application of bonding agent provided the highest repair shear bond strength values, suggesting that they might be adequate methods to improve the quality of repairs of resin composites.
Asunto(s)
Resinas Compuestas/química , Recubrimiento Dental Adhesivo , Grabado Dental/métodos , Láseres de Estado Sólido , Silanos/química , Grabado Ácido Dental/métodos , Resinas Acrílicas/química , Óxido de Aluminio/química , Reparación de Restauración Dental , Análisis del Estrés Dental/instrumentación , Humanos , Ensayo de Materiales , Ácidos Fosfóricos/química , Cementos de Resina/química , Resistencia al Corte , Estrés Mecánico , Propiedades de Superficie , Temperatura , Factores de TiempoRESUMEN
The current study evaluated the influence of a novel surface treatment that uses a low-fusing porcelain glaze for promoting a bond between zirconia-based ceramic and a dual-cure resin luting agent. Bond strengths were compared with those from airborne particle abrasion, hydrofluoric acid etching, and silanization-treated surfaces. Twenty-four yttrium-stabilized tetragonal zirconia (Cercon Smart Ceramics, Degudent, Hanau, Germany) discs were fabricated and received eight surface treatments: group 1: 110 µm aluminum oxide air-borne particle abrasion; group 2: 110 µm aluminum oxide airborne particle abrasion and silane; group 3: 50 µm aluminum oxide airborne particle abrasion; group 4: 50 pm aluminum oxide airborne particle abrasion and silane; group 5: glaze and hydrofluoric acid;group 6: glaze, hydrofluoric acid, and silane;group 7: glaze and 50 pm aluminum oxide airborne particle abrasion; and group 8: glaze,50 pm aluminum oxide airborne particle abrasion and silane. After treatment, Enforce resin cement (Dentsply, Caulk, Milford, DE, USA) was used to fill an iris cut from microbore Tygontubing that was put on the ceramic surface to create 30 cylinders of resin cement in each treatment group (n=30). Micro shear bond test-ing was performed at a cross head speed of 0.5mm/min. One-way analysis of variance, and multiple comparisons were made using Tukey's test (p<0.5). The bond strength was affected only by surface treatments other than silanization. The groups that utilized the low-fusing porcelain glaze with airborne particle abrasion or hydrofluoric acid showed bond strength values statistically superior to groups that utilized conventional airborne particle abrasion treatments with 50 or 110 pm aluminum oxide (p<0.001). The treatment that utilized low-fusing porcelain glaze and hydrofluoric acid showed bond strength values statistically superior to remaining groups (p<0.001). Treatment of zirconia ceramic surfaces with a glaze of low-fusing porcelain significantly increased the bond strength of a dual-cure resin luting agent to the ceramic surface.