RESUMEN
OBJECTIVE: This study aimed to evaluate the effect of ultrasonic activation of etch-and-rinse and self-etch adhesive systems on the bond strength of resin cement to irradiated root dentin. MATERIALS AND METHODS: Eighty human maxillary anterior teeth were distributed into 8 groups (n = 10), according to the type of adhesive system used (etch-and-rinse and self-etch), the ultrasonic activation of the adhesive systems, and the dentin condition (irradiated or non-irradiated - 70 Gy). Endodontic treatment was performed followed by fiberglass post-space preparation. After fiberglass posts' luting, the roots were transversely sectioned on dentin discs and submitted to the push-out bond strength test (0.5 mm/min). The fractured specimens were analyzed under a stereomicroscope and Scanning Electron Microscope (SEM) for failure mode classification. One of the dentin discs was analyzed under SEM to evaluate the characteristics of the adhesive interface. RESULTS: Irradiated specimens had lower bond strength than non-irradiated specimens (P < 0.0001). Ultrasonic activation of both adhesive systems increased the bond strength of the resin cement to irradiated dentin (P < 0.0001). Radiotherapy significantly affected the failure mode in the middle (P = 0.024) and apical thirds (P = 0.032) (adhesive failure). CONCLUSION: Non-irradiated specimens had a more homogeneous adhesive interface. When ultrasonically activated, both adhesive systems showed a greater number of resinous tags, regardless of the dentin condition. CLINICAL RELEVANCE: Ultrasonic activation of adhesive systems is a feasible strategy to enhance fiberglass posts retention in oncological patients.
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Recubrimiento Dental Adhesivo , Dentina , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Técnica de Perno Muñón , Cementos de Resina , Humanos , Cementos de Resina/química , Recubrimiento Dental Adhesivo/métodos , Dentina/efectos de la radiación , Técnicas In Vitro , Recubrimientos Dentinarios/química , Análisis del Estrés Dental , Propiedades de Superficie , Raíz del Diente/efectos de la radiación , Ultrasonido , Grabado Ácido Dental , Incisivo , Vidrio/químicaRESUMEN
This study aimed to compare the effect of silver diamine fluoride (SDF) and fluoride varnish (NaF) on the Vickers microhardness (VHN) of enamel and dentin after radiotherapy and pH-cycling. Human premolars were cut longitudinally, embedded and serially polished. The VHN of enamel/dentin and irradiated enamel/dentin were evaluated. The irradiated specimens were treated with either NaF or SDF, subjected to pH-cycling then VHN test for 4 days. Consequently, they were subjected to energy-dispersive X-ray (EDX) analysis. Radiation adversely affect enamel VHN (p<0.05), whereas dentin VHN was not affected (p>0.05). After pH-cycling, a significant decrease in dentin VHN was observed on day 2 for all groups, whereas enamel VHN was significantly decreased in the control group on day 4. SDF-treated enamel demonstrated higher VHN than that of NaF on day 3. Caries prevention effect of SDF and NaF were observed on enamel, where SDF was proved to be superior to NaF.
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Caries Dental , Esmalte Dental , Fluoruros Tópicos , Dureza , Compuestos de Amonio Cuaternario , Compuestos de Plata , Fluoruro de Sodio , Humanos , Caries Dental/prevención & control , Compuestos de Amonio Cuaternario/farmacología , Esmalte Dental/efectos de los fármacos , Esmalte Dental/efectos de la radiación , Dentina/efectos de los fármacos , Dentina/efectos de la radiación , Cariostáticos , Diente Premolar , Técnicas In Vitro , Concentración de Iones de Hidrógeno , Espectrometría por Rayos X , Raíz del Diente/efectos de los fármacos , Raíz del Diente/efectos de la radiaciónRESUMEN
Objective: To present a case report of maxillary lateral incisor root regeneration after severe root resorption, treated with photobiomodulation (PBM). Background: Impacted maxillary canines often come with the risk of maxillary lateral incisor root resorption, which is widely recognized as the predominant adverse effect in these situations. This progressive process of root resorption is currently irreversible, with no known way to reverse it. Materials and methods: A male patient was 14 years old. Radiographically it was observed that canine 23 is impacting against the root of 22 producing signs of root resorption and having a less than 1:1 crown-to-root ratio with mobility grade 1. From the beginning of the treatment, PBM-assisted orthodontics was proposed. To address the patient's dental concerns, the treatment plan outlined the extraction of the deciduous upper left canine tooth leaving the lateral as long as possible in the mouth. During each appointment, PBM was applied with a diode laser. The wavelength was 810 nm, Ap = 0.2 W, 4.4 J, 22 sec every 21 days, 13 applications in total (57.2J), with a 400 µm inactive surgical tip, in a scanning movement, 1 mm from the mucosa while moving following the vestibular surface of the upper left lateral and canine roots. Results: After 12 months, the 22 had root neoformation and complete closure of the apex with vitality. Conclusions: PBM with an 810 nm diode laser in this clinical case promoted root regeneration of an upper lateral incisor, with severe root resorption, owing to an impacted maxillary canine while still vital.
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Diente Canino , Incisivo , Terapia por Luz de Baja Intensidad , Resorción Radicular , Diente Impactado , Humanos , Masculino , Resorción Radicular/etiología , Adolescente , Regeneración/efectos de la radiación , Maxilar , Raíz del Diente/efectos de la radiación , Láseres de Semiconductores/uso terapéuticoRESUMEN
INTRODUCTION: This study aimed to investigate the effect of radiotherapy and taper of root canal preparation on the biomechanical behavior of mesial roots of mandibular molars. METHODS: Eighty mandibular molars with 2 canals in the mesial root were randomly allocated into 2 groups (n = 40): one group underwent irradiation (60 Gy), while the other did not. Subsequently, the mesial roots were sectioned and each group was subdivided into 5 subgroups (n = 8), according to the preparation taper: no preparation (control); 25.03; 25.04; 25.06; and 25.08. All groups were considered homogeneous regarding their dimensions, weight, and morphology. The prepared specimens were embedded in cylindrical plastic molds and subjected to a cyclic fatigue test. A failure analysis was performed according to the extension and course of the fractures. Two-way ANOVA, Tukey's post-hoc, Fisher's exact, and Kaplan-Meier tests were conducted to evaluate the obtained data (α = 5%). RESULTS: Fatigue resistance decreased as the taper of the preparation increased (P < .05). Preparation 25.03 presented significantly higher values only than 25.08 (P < .05), while 25.04, 25.06, and 25.08 were considered similar (P > .05). Irradiation significantly reduced the biomechanical performance (P < .05). Survival analysis corroborated these findings. There were no differences in the distribution of fracture types among the groups (P > .05). CONCLUSION: The biomechanical behavior of the mesial roots of the mandibular molars decreased significantly in the face of irradiation and as the taper of the preparation increased.
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Mandíbula , Diente Molar , Preparación del Conducto Radicular , Raíz del Diente , Humanos , Fenómenos Biomecánicos , Preparación del Conducto Radicular/métodos , Raíz del Diente/efectos de la radiación , Análisis del Estrés DentalRESUMEN
To evaluate the effect of ultrasonic activation of the endodontic sealer on its intratubular penetration and bond strength to irradiated root dentin. Forty human teeth were distributed into 4 groups (n = 10), according to the radiation therapy (RT) exposure-70 Gy-and ultrasonic activation (UA) of the endodontic sealer: RT/UA-irradiated teeth and sealer UA; RT/no-UA-irradiated teeth and no sealer UA; no-RT/UA-non-irradiated teeth and sealer UA and no-RT/no-UA-non-irradiated teeth and no sealer UA. Push-out bond strength test was performed in a Universal Testing Machine. Failure modes and adhesive interface were analyzed under Scanning Electron Microscopy. The data were statistically compared (two-way-ANOVA and posthoc Games-Howell test; Fisher's exact test - α = 5%). The different experimental conditions (radiation and UA) and the root third had a significant effect on push-out bond strength, and the interaction of these factors was significant (p < 0.05). UA of the sealer significantly increased its bond strength to both irradiated and non-irradiated dentin (p < 0.05). The irradiated groups mostly presented adhesive-type failure of the sealer (p < 0.01). Regardless of the irradiation, the ultrasonically activated groups showed a more homogeneous adhesive interface, with the presence of sealer tags in greater density and depth. Ultrasonic activation enhanced the intratubular penetration and the bond strength of the endodontic sealer to irradiated dentin. The impact of ultrasonic activation of the endodontic sealer on teeth undergoing radiotherapy is a gap in the scientific literature that needs to be bridged.
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Recubrimiento Dental Adhesivo , Dentina , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Materiales de Obturación del Conducto Radicular , Humanos , Materiales de Obturación del Conducto Radicular/química , Recubrimiento Dental Adhesivo/métodos , Dentina/efectos de la radiación , Técnicas In Vitro , Análisis del Estrés Dental , Propiedades de Superficie , Ultrasonido , Raíz del Diente/efectos de la radiaciónRESUMEN
The purposes of the study were to evaluate the bond strength of bioceramic TotalFill root repair material (RRM) in retrograde cavities prepared using Er:YAG and Er,Cr:YSGG laser and steel bur, and to analyze failure modes. The root canals of 30 single-rooted teeth were endodontically treated, their root-ends were resected using a diamond bur, and the teeth were randomly divided into three groups (N = 10) according to the retrograde cavity preparation technique: (1) Er:YAG laser, (2) Er,Cr:YSGG laser, and (3) steel bur. All retrograde cavities were filled with the TotalFill RRM which was prepared according to the manufacturers' instructions. Push-out test was performed using universal testing machine, and failure mode was analyzed using a scanning electron microscope. The data were analyzed using one-way ANOVA, post hoc analysis with Bonferroni correction, and Fisher-Freeman-Halton exact test (p < 0.05). In the Er:YAG-, Er,Cr:YSGG-, and steel bur-prepared cavities, mean bond strengths (MPa) were 12.76, 8.44, and 6.01, respectively. The bond strength of the TotalFill RRM to dentin was significantly higher in the Er:YAG laser compared with the steel bur-prepared cavities (p = 0.004). The bond strength was not significantly different between the Er:YAG and Er,Cr:YSGG cavities (p = 0.074) and between the Er,Cr:YSGG and bur cavities (p = 0.648). In the cavities prepared by the Er,Cr:YSGG laser and bur, the failure mode of the TotalFill RRM was predominantly mixed, then adhesive and cohesive. In the Er:YAG laser-prepared cavities, the most common failure mode was adhesive, followed by mixed type and no cohesive failure. The bond strength of the TotalFill RRM to dentin was highest in the group of retrograde cavities prepared by the Er:YAG laser.
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Cerámica/química , Recubrimiento Dental Adhesivo/métodos , Dentina/química , Dentina/efectos de la radiación , Láseres de Estado Sólido , Raíz del Diente/química , Raíz del Diente/efectos de la radiación , Recubrimientos Dentinarios/química , HumanosRESUMEN
Objective: To evaluate the push-out bond strength and modes of failure of fiber post to root dentin by using photodynamic therapy (PDT), Er,Cr:YSGG, Nd:YAG laser, and conventional cleaning and shaping (CCS). Materials and methods: Eighty anterior teeth were sectioned in a horizontal manner being 2 mm incisal to the cementoenamel junction, and root canal was prepared for post space. After post space was made, fiber posts were placed inside the root canal system. The fiber posts were subjected to PDT, Er,Cr:YSGG laser, Nd:YAG laser, and conventional cleaning and shaping (CSS) with 20 specimens in each group. Cervical and apical sections were obtained from the specimens. For performing the push-out test, the universal testing machine was used. The formula used for calculating the push-out bond strength was σ = N/mm2. Results: PDT group (8.16 ± 2.19 MPa) achieved the highest mean push-out bond strength, whereas Er,Cr:YSGG (7.24 ± 1.27 MPa) reported the lowest value in the specimens. Among the experimental groups, the ANOVA test expressed statistical difference (p = 0.481). In the cervical segments, the mean push-out bond strength was found to be higher in all of the experimental groups. For the cervical segments, the independent t-test results showed higher mean push-out bond strength values than the apical segments in PDT, Er,Cr:YSGG, Nd:YAG, and CSS groups, respectively (p < 0.05). Twenty failures were observed at the interface level between the adhesive and surface of dentin. Seven failures were found at the interface between mixed and the adhesive and post, respectively. Conclusions: Push-out bond strength to root canal dentin was not affected by PDT, Er,Cr:YSGG, and Nd:YAG laser compared with CCS. However, PDT produced the smallest number of failure modes and slightly higher push-out bond strength to root dentin. Laser treatment using PDT and Er,Cr:YSGG appeared to be clinically efficient showing acceptable push-out bond strength of fiber post with less number of failures at different regions of the root dentin.
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Cavidad Pulpar/efectos de la radiación , Dentina/efectos de la radiación , Láseres de Semiconductores , Láseres de Estado Sólido , Técnica de Perno Muñón , Raíz del Diente/efectos de la radiación , Recubrimiento Dental Adhesivo , Análisis del Estrés Dental , Humanos , Técnicas In Vitro , Incisivo , Ensayo de Materiales , Preparación del Conducto Radicular/métodos , Propiedades de SuperficieRESUMEN
Objective: To investigate the effects of Er:YAG laser on the attachment of human periodontal ligament fibroblasts (hPDLFs) to denuded root surfaces simulating delayed replantation cases. Background data: Dental avulsion is one of the most severe dental traumas, which is often treated with replantation. In delayed replantation scenarios, poor prognosis, including root resorption, usually occurs due to poor root surface conditioning and nonviable hPDLF attachment. Methods: Thirty-six root fragments (5 × 5 × 2 mm) were obtained from periodontium tissue-free premolar root surfaces. Specimens were randomly and equally assigned to the following: Group A, untreated control; Group B, 25 J/cm2 and 10 Hz of Er:YAG laser irradiation; and Group C, 50 J/cm2 and 10 Hz of Er:YAG laser irradiation. Some specimens in each group were then prepared for surface topography visualization under SEM, others were subjected to coculture with hPDLF suspension, and cell adhesion was further evaluated by SEM. Results: Group A presented homogenous smooth root surface, with fewer and round-shaped cells attached; Group B and C exhibited rather rough and irregular morphologies, and spindle-shaped fibroblasts were firmly attached by numerous lamellipodia and extensions. After a 3-day coculture, the number of fibroblasts attached in Group A was significantly lower compared with the other two laser-treated groups (p = 0.008 < 0.05). No significant alterations were observed between the two laser groups (p = 0.135 > 0.05). Conclusions: Er:YAG laser-treated root surfaces are compatible for the attachment of PDLFs, which suggests that Er:YAG laser irradiation may be used as a promising strategy for root surface conditioning in delayed replantation cases.
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Fibroblastos/efectos de la radiación , Láseres de Estado Sólido , Ligamento Periodontal/efectos de la radiación , Reimplante Dental , Raíz del Diente/efectos de la radiación , Diente Premolar , Adhesión Celular/efectos de la radiación , Técnicas de Cocultivo , Humanos , Técnicas In Vitro , Microscopía Electrónica de Rastreo , Distribución Aleatoria , Propiedades de SuperficieRESUMEN
This study aimed to compare the effects of diode and Er:YAG laser irradiation of root dentin on push-out bond strength of mineral trioxide aggregate (MTA) and calcium-enriched mixture (CEM) cements. An in vitro experimental study was conducted on 90 dentin discs, cut out of freshly extracted human teeth. The discs were instrumented to obtain 1.3-mm lumen diameter. Then, they were randomly divided into six groups (n = 15). Groups 1 and 4 subjected to diode laser (Wiser, Doctor Smile, Italy) (980 nm, 1 W, continuous mode) for 10 s and filled with MTA and CEM cements. Groups 2 and 5 subjected to Er:YAG laser (Deka, Italy) (2940 nm, 1 W, 10 Hz, 230 µs) for 10 s and filled with MTA and CEM cements. Groups 3 and 6 (control groups) were filled with MTA and CEM cements without laser irradiation. After 7 days, push-out bond strength test was performed using a universal testing machine in order to evaluate the adhesion of the biomaterials to dentin. The samples were evaluated under a light microscope at × 40 magnification to determine the mode of fracture. Data were analyzed using two-way ANOVA. The highest push-out bond strength (8.76 ± 3.62 MPa) was noted in group 1 (diode/MTA), which was significantly higher than the other groups (P < 0.001). The lowest bond strength (2.61 ± 0.81) was noted in group 6 (control/CEM). Diode laser significantly increased the bond strength of both cements (P < 0.05), but Er:YAG laser irradiation only increased the bond strength of CEM and had no significant effect on MTA (P = 0.603). The bond strength of MTA control group was higher than that of CEM control group (P = 0.001). Push-out bond strength of endodontic cements can be affected by dentin conditioning with diode 980 nm and Er:YAG laser. Nine hundred eighty-nanometer diode laser irradiation is recommended to increase the bond strength of endodontic cements particularly the CEM cement to dentin.
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Compuestos de Calcio/química , Recubrimiento Dental Adhesivo , Dentina/efectos de la radiación , Láseres de Semiconductores , Láseres de Estado Sólido , Óxidos/química , Compuestos de Fósforo/química , Cemento de Silicato/química , Silicatos/química , Raíz del Diente/efectos de la radiación , Compuestos de Aluminio/química , Combinación de Medicamentos , HumanosRESUMEN
PURPOSE: In clinical prosthetics procedures, including endodontics and post fixation, the presence of a smear layer can reduce the post bond strength. An Er,Cr:YSGG laser, which emits at 2780 nm, can promote a smear-layer-free surface due to the ablation process. Considering these aspects, the purpose of this work was to evaluate the influence of Er,Cr:YSGG laser irradiation using either a radial or an axial fiber tip on the bond strength of three resin cements to the fiber-reinforced composite posts. MATERIALS AND METHODS: Ninety recently extracted single rooted human teeth had their root canal instrumented and were randomly distributed into nine experimental groups, in which three resin cements (total-etching Variolink II, self-etching Panavia F, and self-adhesive RelyX Unicem Aplicap) and three root canal treatments (no treatment, laser irradiation using the radial fiber tip, laser irradiation using the axial fiber tip) were used. Specimens were then sectioned into three sections (cervical, middle, and apical thirds) with two slices on each section. A push-out test was performed on each slice, and the values were recorded as MPa. The push-out data were analyzed by a Ryan-Joiner normality test followed by a two-way ANOVA test and Tukey pairwise comparison. The statistical analysis was performed on each third section separately, with a 5% significance level. RESULTS: Laser irradiation with axial fiber tip significantly increased the post bond strength of RelyX Unicem Aplicap on middle third of specimens (p < 0.001) when compared to other root canal treatments (unlased or irradiated with radial tip). Considering the Panavia resin cement, laser irradiation with either axial or radial tips promoted a significant increase on the post bond strength of middle third when compared to unlased specimens (p < 0.001); however, laser irradiation did not influence the post bond strength of Variolink resin cement. CONCLUSIONS: The use of the Er,Cr:YSGG laser for clinical prosthetics procedures enhances the post bond strength of Panavia and RelyX Unicem Aplicap resin cements, mainly at middle third of roots, and does not interfere with the bond strength of Variolink resin cement. For the RelyX Unicem Aplicap system, the use of axial tip is most advantageous and can be recommended for future clinical application.
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Recubrimiento Dental Adhesivo/métodos , Láseres de Estado Sólido/uso terapéutico , Cementos de Resina/química , Cementos de Resina/efectos de la radiación , Tratamiento del Conducto Radicular/instrumentación , Tratamiento del Conducto Radicular/métodos , Raíz del Diente/efectos de la radiación , Grabado Dental/métodos , Cavidad Pulpar/efectos de la radiación , Análisis del Estrés Dental , Vidrio , Humanos , Ensayo de Materiales , Técnica de Perno Muñón/instrumentación , Dosis de Radiación , Preparación del Conducto Radicular/instrumentación , Preparación del Conducto Radicular/métodos , Auto-Curación de Resinas Dentales , Estrés MecánicoRESUMEN
BACKGROUND: The radiotherapy can directly affect the bond strength of the adhesive materials, interfering in the prognosis of restorative treatments, which may be caused by chemical changes in dentin structure. METHODS: Twenty inferior homologues premolars were distributed in 2 groups (in vitro study) (n = 10): nonirradiated and irradiated. The specimens were submitted to the analysis of phosphate (ν1 PO43- ;ν2 PO43- ;ν4 PO43- ), carbonate (ν3 CO32- ), amide I, CH2 , amide III, and amide I/III ratio by confocal Raman spectroscopy. Data were submitted to statistical analysis (T test, P < .05). RESULTS: In intracanal dentin, the irradiated group had lower ν4 PO43- values (1.23 ± 0.06) compared to nonirradiated group (1.40 ± 0.18) (P < .05), with no difference for ν1 PO43- and ν2 PO43 peaks (P > .05). The irradiated (1.56 ± 0.06) had lower carbonate, amide III (1.05 ± 0.19), and amide I/III ratio values (0.19 ± 0.06) compared to nonirradiated group (1.42 ± 0.10, 1.28 ± 0.24, and 0.31 ± 0.10, respectively) (P < .05). For medium dentin irradiated group (1.30 ± 0.12) had lower phosphate values compared to nonirradiated group (1.48 ± 0.22) (P < .05). In cementum, there was no statistical difference between the groups. CONCLUSION: The radiotherapy was able to cause changes in ν4 PO43- , carbonate, and amide III peaks of root dentin.
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Dentina/química , Dentina/efectos de la radiación , Raíz del Diente/química , Raíz del Diente/efectos de la radiación , Amidas/análisis , Diente Premolar/química , Diente Premolar/efectos de la radiación , Carbonatos/análisis , Neoplasias de Cabeza y Cuello/radioterapia , Humanos , Fosfatos/análisis , Espectrometría RamanRESUMEN
OBJECTIVE: To investigate effects of HIFU on macrophage phenotype, surface micro-topography and nano-scale surface mechanical properties of dental cementum. MATERIALS AND METHODS: Root discs (2 mm thickness) were cut apical to CEJ and sectioned into quadrants. HIFU setup with bowl-shaped piezo ceramic transducer submerged in a water tank was used for exposure on each specimen for 15 s, 30 s or 60 s. The specimens of the control group were left without any HIFU exposure. HIFU was generated with a continuous sinusoidal wave of 120Vpp amplitude, 250 KHZ resonance-frequency and highest ultrasonic pressure of â¼10 bar at the focus. Specimens for SEM were viewed, and micro-topography characterization performed, using AFM and Ra parameter and surface area (SA) calculated by specialized SPM surface analysis software. For nano-indentation testing, experiments were carried out using AFM. Macrophage cell isolation and culturing was performed on cementum to receive the HIFU treatment at different time periods. Raman spectroscopy were scanned to create spectra perpendicular to the cementum substrate to analyze generation of standard spectra for Raman intensity ratio of hydroxyapatite normalized to the peaks ν1 960 cm-1. Data was expressed as means ± standard deviations and analyzed by one-way ANOVA in term of Ra, SA, H and Er. Different points for fluorescence intensity ratio were analyzed by Raman using Wilcoxon rank sum test. RESULTS: HIFU exposure at 60 s removed the smear layer and most of cementum appeared smoothened. AFM characterisation, showed a slight decrease in the irregularity of the surface as exposure time increased. Intact macrophages can be identified in control and all experimental HIFU groups. The level of fluorescence for the control and HIFU 15 and 30 s were low as compared to HIFU 60 s. CONCLUSION: If HIFU can be successfully implemented, it may be a possible alternative to current methods used in periodontal therapy to achieve smooth root surfaces.
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Cemento Dental/metabolismo , Cemento Dental/efectos de la radiación , Tratamiento con Ondas de Choque Extracorpóreas/métodos , Macrófagos/metabolismo , Macrófagos/efectos de la radiación , Análisis de Varianza , Cemento Dental/ultraestructura , Relación Dosis-Respuesta en la Radiación , Durapatita , Fluorescencia , Enfermedades Periodontales/radioterapia , Dosis de Radiación , Espectrometría Raman , Propiedades de Superficie/efectos de la radiación , Factores de Tiempo , Raíz del Diente/efectos de la radiación , Raíz del Diente/ultraestructura , TransductoresRESUMEN
Root-filled teeth that received fiber posts most frequently fail at the adhesive interface between resin cement and dentin. The objective of this study is to evaluate the effect of Er:YAG laser and/or sodium ascorbate (SA) on bond strength, microhardness of dentin, and penetration depth of cement into dentinal tubules. Forty-eight bovine incisor roots were endodontically treated, post spaces were prepared and equally divided into four groups (n = 12): G1-distilled water (control); G2-10% SA (10 min); G3-Er:YAG laser (150 mJ/4 Hz/40 s), and G4-Er:YAG laser + 10% SA. Glass fiber posts were cemented and roots sectioned into slices. In the first slice, the push-out bond strength (MPa) and failures were analyzed by confocal laser scanning microscope (CLSM). The second slice was subjected to microhardness test (KHN) and CLSM to assess the cement penetration. ANOVA and Tukey test were used for bond strength and microhardness data and Kruskal-Wallis and Dunn tests for the cement penetration (α = .05). The SA-treated samples had higher bond strength (10.02 ± 5.45a), similar to Er:YAG laser (9.91 ± 4.62a) and Er:YAG laser + SA (8.09 ± 4.07a). The least values (P < .05) were found on control (4.02 ± 2.39b). Significant differences were observed on root thirds (P < .05): cervical > middle > apical. There was a predominance of adhesive failures. The microhardness test revealed no differences between groups (P > .05). The experimental groups (G2, G3, and G4) had highest penetration into dentinal tubules when compared to the control (G1). Dentin pretreatments with Er:YAG laser or SA improved bond strength of cement-post-dentin interfaces; however, no synergistic effect of both treatments combined was observed.
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Ácido Ascórbico/farmacología , Recubrimiento Dental Adhesivo , Dentina/efectos de la radiación , Vidrio/química , Láseres de Estado Sólido , Animales , Bovinos , Cementos Dentales/farmacología , Dureza , Ensayo de Materiales , Cementos de Resina/farmacología , Raíz del Diente/efectos de los fármacos , Raíz del Diente/efectos de la radiaciónRESUMEN
This in vitro study evaluated the influence of the Er,Cr:YSGG laser, associated or not to desensitizing agents, in the prevention of acid erosion in bovine root dentin. Eighty dentin specimens were selected and divided into eight groups (n = 10): G1: negative control; G2: positive control (5% fluoride varnish-FV); G3: Er,Cr:YSGG laser; G4: FV + laser; G5: 3% potassium oxalate; G6: 3% potassium oxalate + laser; G7: biphasic calcium silicate/phosphate gel (gel); G8: gel + laser. Laser parameters: 0.5 W, 6.25 J/cm2 at 1-mm distance. The erosive drink used was a cola soft-drink (pH = 2.42 at 4 °C), lasting 5 min, twice a day, with 6-h intervals between the challenges, during 14 days. Kolmogorov-Smirnov and Levene's tests were satisfied. The surface roughness data were submitted to ANOVA and Tukey post hoc tests. For the wear profile, Kruskal-Wallis and Dunn post hoc tests were used. Afterwards, the Spearman correlation test was performed. All statistical tests assumed a significance level of 5% (α = 0.05). G1 presented the highest surface roughness value after the erosive challenge (3.586 µm2 ± 0.205 µm2) and the G7 presented the lowest surface roughness value after the erosive challenge (1.071 µm2 ± 0.180 µm2). For the lost volume, G4 presented the lowest percentage (9.7% ± 0.9%), while G1 had the highest percentage (41.8% ± 2.5%), both with p < 0.05. There was a weak correlation between the response variables (ρ = 0.33). All groups presented lower values of surface roughness and loss of volume when compared to the negative control group. For the surface roughness, the biphasic calcium silicate/phosphate gel presented the best result. For volume loss, the 5% fluoride varnish + Er,Cr:YSGG laser showed the best results compared to the other groups.
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Ácidos/efectos adversos , Desensibilizantes Dentinarios/farmacología , Dentina/efectos de la radiación , Láseres de Estado Sólido , Erosión de los Dientes/prevención & control , Raíz del Diente/efectos de la radiación , Animales , Bovinos , Dentina/efectos de los fármacos , Estadísticas no Paramétricas , Propiedades de Superficie , Raíz del Diente/efectos de los fármacosRESUMEN
The aim of this study was to evaluate the influence of radiation therapy on root canal sealer push-out bond strength (BS) to dentin and the sealer/dentin interface after different final irrigation solutions (NaOCl, EDTA, and chitosan). Sixty-four maxillary canines were distributed into two groups (n=30): non-irradiated and irradiated with 60 Gy. Canals were prepared with Reciproc-R50 and subdivided (n=10) for final irrigation (NaOCl, EDTA, chitosan) and filled. Three dentin slices were obtained from each root third. The first slice of each third was selected for BS evaluation, and the failure mode was determined by stereomicroscopy. SEM analysis of the sealer-dentin interface was performed in the remaining slices. Two-way ANOVA and Tukey's tests (α=0.05) were used. Lower BS (P<0.0001) was obtained after irradiation (2.07±0.79 MPa), regardless of the final irrigation solution used. The NaOCl group (P<0.001) had the lowest BS in the irradiated (1.68±0.72) and non-irradiated (2.39±0.89) groups, whereas the EDTA (irradiated: 2.14±0.77 and non-irradiated: 3.92±1.54) and chitosan (irradiated: 2.37±0.73 and non-irradiated: 3.51±1.47) groups demonstrated a higher BS (P<0.05). The highest values were observed in the coronal third (3.17±1.38) when compared to the middle (2.74±1.36) and apical ones (2.09±0.97)(P<0.0001). There were more cohesive failures and more gaps in irradiated specimens, regardless of the final solution. The present study showed that radiation was associated with a decrease in BS, regardless of the final solution used, whereas chitosan increased BS in teeth subjected to radiation therapy.
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Recubrimiento Dental Adhesivo/métodos , Dentina/efectos de los fármacos , Dentina/efectos de la radiación , Resinas Epoxi/efectos de la radiación , Materiales de Obturación del Conducto Radicular/efectos de la radiación , Irrigantes del Conducto Radicular/efectos de la radiación , Análisis de Varianza , Quitosano/química , Fracaso de la Restauración Dental , Ácido Edético/química , Resinas Epoxi/química , Neoplasias de Cabeza y Cuello/radioterapia , Humanos , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Reproducibilidad de los Resultados , Materiales de Obturación del Conducto Radicular/química , Irrigantes del Conducto Radicular/química , Hipoclorito de Sodio/química , Estadísticas no Paramétricas , Propiedades de Superficie/efectos de los fármacos , Propiedades de Superficie/efectos de la radiación , Raíz del Diente/efectos de los fármacos , Raíz del Diente/efectos de la radiaciónRESUMEN
The aim of this study was to evaluate the chemical and morphological effects of different lasers as a final surface treatment for endodontic therapy through energy dispersive X-ray spectroscopy (EDS) and scanning electron microscopy (SEM) respectively. Twenty-five maxillary canines were selected and instrumented with K3 system. Roots were randomly distributed into five groups (n = 5) according to the surface treatment: GI (distilled water), GII (NaOCl + EDTA), GIII (NaOCl + EDTA + 980 nm diode laser), GIV (NaOCl + EDTA+ 1,064 nm Nd:YAG laser), and GV (NaOCl + EDTA+ 2,780 nm Er, Cr:YSGG laser). Lasers were applied for 20 s and samples were bisected, exposing the treated surface and then subjected to elements quantification by EDS and morphological evaluation by scanning electron microscope (SEM). EDS data were submitted to ANOVA-two way, and SEM scores were submitted to two-way Kruskal-Wallis and Dunn's tests. The EDS analysis showed no difference for the chemical elements and Ca/P ratio between groups (p > .05). Statistical analysis showed more intense results for GV and less intense results for GI (p < .05). The GIII showed an amorphous organic matrix surface, while GV provided greater removal of intertubular dentin forming craters, and GIV promoted dentin fusion. The EDS method used in this study was not able to verify any chemical changes in root canal dentin; Nd:YAG, Er, Cr:YSGG, and 980 nm diode laser were capable of modifying the dentin morphology, correlating characteristics features for each one, which are essential clinical knowledge to establish the correct indication for each case. RESEARCH HIGHLIGHTS: EDS was not able to verify any chemical changes in root canal dentin after 980 nm diode, Nd:YAG and Er;Cr:YSGG laser treatments Nd:YAG, Er, Cr:YSGG, and 980 nm diode laser modified dentin morphology, correlating characteristics features for each one.
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Diente Canino/efectos de la radiación , Dentina/efectos de la radiación , Terapia por Luz de Baja Intensidad , Raíz del Diente/efectos de la radiación , Diente no Vital , Diente Canino/anatomía & histología , Diente Canino/química , Dentina/anatomía & histología , Dentina/química , Humanos , Microscopía Electrónica de Rastreo , Espectrometría por Rayos X , Propiedades de Superficie/efectos de la radiación , Raíz del Diente/anatomía & histología , Raíz del Diente/químicaRESUMEN
OBJECTIVES: The aim of the present study was to investigate differences in the amount of dentin microcracking caused by the use of a 970-nm diode laser with different parameters for endodontic disinfection procedures. MATERIALS AND METHODS: Forty dental roots underwent mechanical endodontic preparation in a standardized manner. Each sample was randomly allocated to 4 groups receiving constant or interval laser irradiation time, calcium hydroxide disinfection, or a control group, with 10 samples per group. Transmission microscopy of all samples was performed at T0, before preparation; T1, immediately after endodontic preparation; and T2, after laser application in the laser groups and after 1 week of storage in the control and calcium hydroxide groups. The microcracks at each measurement point were color labeled, layered, and compared. RESULTS: No significant differences were noted at T0 and T1 (p > 0.05). Statistically significant differences in the overall amount of microcracking were observed between the constant laser group and all other groups at T2 (p < 0.05). There were no statistically significant differences between the interval laser group, the calcium hydroxide group, and the control group at T2 in relation to the overall amount of microcracking (p > 0.05). When the root sections were analyzed separately, the coronal section did not show any statistically significant differences between the constant laser and interval laser groups (p > 0.05). The middle and apical root sections in the constant laser group showed the significantly largest amount of crack formation in comparison with the other groups (p < 0.05). The statistically significantly smallest amount of crack formation was observed in the apical third for all groups (p < 0.05). CONCLUSIONS: Clinically proposed laser protocol seems to be able to prevent side effects to the tissue, such as microcracks of the root canal dentine.
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Cavidad Pulpar/efectos de la radiación , Dentina/efectos de la radiación , Desinfección/métodos , Láseres de Semiconductores , Preparación del Conducto Radicular/métodos , Fracturas de los Dientes/etiología , Raíz del Diente/efectos de la radiación , Humanos , Técnicas In VitroRESUMEN
INTRODUCTION: The purpose of this 2-arm-parallel split-mouth trial was to investigate the effect of low-level laser therapy (LLLT) on the repair of orthodontically induced inflammatory root resorption (OIIRR). METHODS: Twenty patients were included in this study, with 1 side randomly assigned to receive LLLT, and the other side served as a sham. Eligibility criteria included need for bilateral maxillary first premolar extractions as part of fixed appliance treatment. OIIRR was generated by applying 150 g of buccal tipping force on the maxillary first premolars for 4 weeks. After the active force was removed, the teeth were retained for 6 weeks. LLLT commenced with weekly laser applications using a continuous beam 660-nm, 75-mW aluminum-gallium-indium-phosphorus laser with 1/e2 spot size of 0.260 cm2, power density of 0.245 W/cm2, and fluence of 3.6 J/cm2. Contact application was used at 8 points buccally and palatally above the mucosa over each tooth root for 15 seconds with a total treatment time of 2 minutes. After 6 weeks, the maxillary first premolars were extracted and scanned with microcomputed tomography for primary outcome OIIRR calculations. Subgroup analysis included assessment per root surface, per vertical third, and sites of heaviest compressive forces (buccal-cervical and palato-apical). Randomization was generated using www.randomization.com, and allocation was concealed in sequentially numbered, opaque, sealed envelopes. Blinding was used for treatment and outcome assessments. Two-tailed paired t tests were used to determine whether there were any statistically significant differences in total crater volumes of the laser vs the sham treated teeth. RESULTS: Total crater volumes were 0.746 mm3 for the laser treated teeth and 0.779 mm3 for the sham. There was a mean difference of 0.033 ± 0.39 mm3 (95% CI, -0.21 to 0.148 mm3) greater resorption crater volume in the sham group compared with the laser group; this was not statistically significant (P = 0.705). No harm was observed. CONCLUSIONS: No significant difference was found between LLLT and sham control groups in OIIRR repair.
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Cemento Dental/patología , Cemento Dental/efectos de la radiación , Terapia por Luz de Baja Intensidad , Resorción Radicular/radioterapia , Técnicas de Movimiento Dental/métodos , Raíz del Diente/patología , Raíz del Diente/efectos de la radiación , Adolescente , Diente Premolar/patología , Diente Premolar/efectos de la radiación , Método Doble Ciego , Femenino , Humanos , Masculino , Diseño de Aparato Ortodóncico , Soportes Ortodóncicos , Alambres para Ortodoncia , Estrés Mecánico , Extracción Dental , Técnicas de Movimiento Dental/instrumentación , Resultado del Tratamiento , Microtomografía por Rayos XRESUMEN
This in vitro study evaluated the compositional, crystalline, and morphological effects promoted by Nd:YAG laser on root dentin, and verified the effects of laser and topical acidulated phosphate fluoride application (APF-gel) on dentin erosion. 180 bovine dentin slabs were randomized into 4 groups (n = 45): G1-untreated, G2-APF-gel (1.23% F-, 4 min), G3-Nd:YAG (1064 nm, 84.9 J/cm², 10 Hz), and G4-APF-gel application followed by Nd:YAG laser irradiation. The compositional, crystalline, and morphological effects promoted by treatments were investigated on five samples of each experimental group. The other samples were submitted to a 5-day, 10-day, or 15-day erosive and abrasive demineralization and remineralization cycling in order to create erosion lesions. The area and depth of lesions, as well as the optical attenuation coefficient, were assessed, and all data were statistically analysed (p < 0.05). Nd:YAG laser promoted the reduction of carbonate, the formation of tetracalcium phosphate, as well as the melting and recrystallization of the dentin surface. Laser significantly decreased the area and depth of erosion lesions and altered the optical attenuation coefficient when compared to untreated and APF-gel groups, but the association of APF-gel and laser did not promote an additional effect. Nd:YAG laser irradiation can be a promissory treatment to prevent dentin erosion and the abrasion process.
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Fluoruro de Fosfato Acidulado/farmacología , Dentina/efectos de los fármacos , Dentina/efectos de la radiación , Láseres de Estado Sólido , Erosión de los Dientes/prevención & control , Animales , Bovinos , Cristalización , Dentina/química , Microscopía Electrónica de Rastreo , Estructura Molecular , Distribución Aleatoria , Espectroscopía Infrarroja por Transformada de Fourier/métodos , Raíz del Diente/química , Raíz del Diente/efectos de los fármacos , Raíz del Diente/efectos de la radiaciónRESUMEN
OBJECTIVES: Post-radiation dental lesions affect mainly the cervical area of the tooth. Until now, there are quite few evidences regarding the effects of radiation exposure on root dentin breakdown. To better understand this effect, we used human root dentin specimens obtained from third molars from similarly aged individuals. MATERIALS AND METHODS: Twenty specimens were analyzed by the surface hardness (SH), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD) to evaluate the baseline properties of their root dentin. Other six human teeth were prepared and analyzed by scanning electron microscopy (SEM). Then the specimens were randomly distributed between two groups (n = 13 per group) and irradiated with a total dose of 55 or 70 Gy in a linear accelerator. The percentage of EDX and surface hardness loss (%SHL) were determined based on measurements before and after irradiation. The specimens were also analyzed after irradiation by SEM and XRD. The Ca/P weight ratio was calculated. RESULTS: Based on SEM analysis, radiation exposure induced dehydration of the dentin. The Ca/P weight ratio decreased (p = 0.0045). The %SHL of specimens irradiated with 70 Gy was higher than that of the 55-Gy group (p < 0.05), although even the lower dose induced root dentin breakdown. CONCLUSIONS: Overall, we can state that radiation exposure changes the composition and structure of human root dentin, which detrimentally affect its hardness. CLINICAL RELEVANCE: The changes reported herein might influence the selection of the dental materials and will bring new knowledge in this field to prevent radiation-related caries in root dentin.