Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 20.729
Filtrar
1.
J Adhes Dent ; 23(3): 223-230, 2021 Jun 05.
Artículo en Inglés | MEDLINE | ID: mdl-34060302

RESUMEN

PURPOSE: To evaluate the effects of pretreatment with different crosslinking agents on glass-fiber-post adhesive luting. MATERIALS AND METHODS: Single-rooted human teeth (n = 20) were randomly assigned to four groups: proanthocyanidins (PA) from grape-seed extract, cardol and cardanol (separated from cashew nut-shell liquid) and negative control (hydroethanolic solution). The solutions were applied on 37% phosphoric acid-etched dentin for 60 s. Glass-fiber posts were cemented using a three-step etch-and-rinse adhesive (Scotchbond Multi-Purpose, 3M Oral Care) and composite cement (RelyX ARC, 3M Oral Care). Slices for the push-out bond strength test were cut and tested after 24-h or 6-month storage in distilled water. The dentin underlying the adhesive layer was analyzed by micro-Raman spectroscopy to evaluate vibrational formation of collagen crosslinks. Three additional slices per group were also made and the adhesive in-situ degree of conversion (DC) was analyzed by micro-Raman spectroscopy. The results were analyzed using two-way ANOVA and Tukey's test (p < 0.05). RESULTS: No statistically significant changes in bond strength were found over time for any of the groups, except with cardol, which increased bond strength (8.4 ± 3.9 MPa at 24 h to 15.0 ± 2.9 MPa after 6 months, p < 0.001) after aging. The formation of peaks at 1117 cm-1 and 1235 cm-1 showed the presence of collagen crosslinks for all three biomodification agents. The DC outcomes showed no statistically significant differences between groups (p = 0.514). CONCLUSION: Biomodification agents did not impair adhesive polymerization. Cardol demonstrated a positive influence on intraradicular dentin bonding for glass-fiber post luting.


Asunto(s)
Técnica de Perno Muñón , Cementos Dentales , Materiales Dentales , Dentina , Humanos , Raíz del Diente
2.
J Adhes Dent ; 23(3): 243-252, 2021 Jun 05.
Artículo en Inglés | MEDLINE | ID: mdl-34060304

RESUMEN

PURPOSE: To investigate the influence of the etching strategy of universal adhesives on bond degradation to sound and artificially-induced caries-affected dentin. MATERIALS AND METHODS: The universal adhesives (Scotchbond Universal Adhesive; All-Bond Universal; Prime&Bond Elect) and adhesives used as controls (Adper Single Bond 2 and Clearfil SE Bond) were applied to sound and artificially-induced caries-affected bovine dentin. Microtensile bond strength was evaluated immediately (24 h) and after one year of water storage (1 year). Representative specimens were also prepared to assess nanoleakage. Bond strength data (MPa) were analyzed using three-way ANOVA and post-hoc Tukey's test (α = 0.05), considering each substrate separately. RESULTS: Bonding degradation was observed for all universal adhesives on caries-affected dentin, irrespective of the etching strategy. On sound dentin, bonding degradation was observed when adhesives were used on the etch-and-rinse strategy. CONCLUSION: The universal adhesives were not capable of maintaining bond stability over time on caries-affected dentin. The self-etch strategy seems better able to maintain the durability of adhesive interfaces created on sound dentin.


Asunto(s)
Recubrimiento Dental Adhesivo , Caries Dental , Animales , Bovinos , Caries Dental/terapia , Susceptibilidad a Caries Dentarias , Dentina , Resistencia a la Tracción
3.
Am J Dent ; 34(2): 80-86, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33940664

RESUMEN

PURPOSE: To evaluate and compare the effect on micro-tensile bond strength (µTBS) of a double layer application of three universal adhesives applied in self-etch mode to proximal dentin/cementum gingival margins of class II direct composite restorations, immediately and after 12 months water storage. METHODS: 66 molars with compound class II cavities, with gingival margin 1 mm below CEJ, were divided into three groups according to the universal adhesive used. The adhesives evaluated included All-Bond Universal (AB), Single Bond Universal (SB), and Prime&Bond Elect (PB). The groups were further subdivided according to adhesive application technique, either single layer or double layer application. All teeth were restored with the same nanofilled resin composite. µTBS were examined at a crosshead speed of 0.5 mm/minute after 24 hours or 12 months water storage. Fracture mode was assessed under stereomicroscope. Data were analyzed by two-way analysis of variance (ANOVA) followed by Tukey's post hoc test (P< 0.05). RESULTS: The double layer application µTBS values were significantly higher than single layer application in all groups. Regardless of the type of adhesive or application technique, all subgroups showed significantly decreased bond strength after aging. There were significant lower µTBS values for AB adhesive compared with the other two adhesives that demonstrated no significant differences between them. The double layer application technique was effective in enhancing µTBS values of all tested adhesives bonded to proximal dentin/cementum gingival margins compared to single layer application. Regardless of application technique, all tested adhesives were incapable of defying long-term water aging. CLINICAL SIGNIFICANCE: The double layer application technique may be recommended to enhance the bonding durability of universal adhesives to face challenges in bonding to dentin-cementum cervical margins.


Asunto(s)
Recubrimiento Dental Adhesivo , Recubrimientos Dentinarios , Cementos Dentales , Cemento Dental , Dentina , Ensayo de Materiales , Cementos de Resina
4.
Am J Dent ; 34(2): 105-109, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33940669

RESUMEN

PURPOSE: To evaluate the chemical composition and morphological properties of eroded dentin after biomodification with phosphorylated chitosan (P-Chi) and carbodiimide (EDC). METHODS: 42 bovine dentin specimens were used; 21 of these specimens were subjected to erosive challenge with 0.3% citric acid (pH = 3.2) for 2 hours. The specimens were randomly divided into six groups according to dentin substrate (sound or eroded) and biomodification [with 2.5% P-Chi, with 0.5 mol/L EDC, or no biomodification (control)]. The specimens were analyzed by Fourier-transform infrared spectroscopy (FTIR, n= 5, in triplicate) and atomic force microscopy (AFM, n= 2) to verify the phosphate, carbonate, and organic matrix absorption peaks and to investigate surface morphology, respectively. The data were analyzed with Origin 6.0. RESULTS: Dentin erosion reduced the intensity of the phosphate (1,100 cm⁻¹) and carbonate (872 cm⁻¹) related bands, which evidenced demineralization. Eroded dentin consisted of a more irregular surface containing slightly more open tubules. Modification with P-Chi removed intertubular dentin, which was compatible with surface demineralization; however, this modification obliterated dentin tubules. EDC did not promote demineralization. Biomodified dentin had a more irregular surface, irrespective of substrate type. CLINICAL SIGNIFICANCE: Eroded dentin demineralization promoted by biomodification with 2.5% phosphorylated chitosan (P-Chi) is a promising indicator for further studies and highlights the dentin intrinsic characteristics. From the point of view of dentin surface chemical analysis, more studies with P-Chi should be conducted to achieve greater interactions with surfaces and to improve the adhesive interface.


Asunto(s)
Carbodiimidas , Quitosano , Animales , Bovinos , Cementos Dentales , Dentina
5.
J Clin Pediatr Dent ; 45(2): 98-103, 2021 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-33951172

RESUMEN

OBJECTIVES: To determine different combinations of marginal ridge shape (MRS) and contact extents in nature of the contact between primary molars and its correlation with the presence of carious lesions on radiographic examination of approximal surfaces. STUDY DESIGN: Retrospective study of 347 clinical records, including photographs and bitewing radiographs, were assessed for intact MRS and caries extent. The carious lesions were scored (0-5, Mejàre scoring system) radiographically and correlated to the intact MRS on clinical photographs, and strength of associations quantified using logistic regression analysis and chi-square tests. RESULTS: Primary molars, 848(contact extent), and 757(MRS) were analyzed. Combination of straight-convex(35.4%) MRS was more common (p<0.001). None of the approximal surfaces were caries-free for straight and straight MRS with 36.4% of both approximal surfaces exhibiting caries in enamel, and 38.2% of one approximal surface exhibiting caries in dentin. Approximately 90% of the primary molars with substantial contacts exhibited carious lesions in the enamel and 80% with light contacts exhibited carious lesions in the dentin (p<0.001). CONCLUSION: Six different combinations of intact MRS were identified. Combination of concave-convex shapes exhibited caries extending into dentin. Substantial and/or light contacts between primary molars showed higher caries experience in the approximal surfaces.


Asunto(s)
Susceptibilidad a Caries Dentarias , Caries Dental , Caries Dental/diagnóstico por imagen , Dentina , Humanos , Diente Molar/diagnóstico por imagen , Radiografía de Mordida Lateral , Estudios Retrospectivos
6.
Swiss Dent J ; 131(5): 425-430, 2021 May 10.
Artículo en Alemán | MEDLINE | ID: mdl-33952268

RESUMEN

Autologous dentin as a bone substitute can be used in regenerative dentistry. Extracted teeth are not discarded but recycled and used in block or particulate form for lateral ridge augmentation before implant insertion. Due to the growth factors contained in the dentin and the autologous origin, a stable and good osseointegration of the augmentation material can be expected. This case report demonstrates how the dentin of an autologous wisdom tooth is used for lateral ridge augmentation in area 15 in a 30-year old female patient. The patient was successfully rehabilitated with an implant afterwards. Even though the indication range is limited due to the availability of dentin and the size of the defect, the procedure represents a promising and comparatively minimally invasive autologous augmentation procedure to expand the oral surgical field in regenerative dentistry.


Asunto(s)
Aumento de la Cresta Alveolar , Tercer Molar , Adulto , Trasplante Óseo , Implantación Dental Endoósea , Dentina , Femenino , Humanos , Tercer Molar/diagnóstico por imagen , Tercer Molar/cirugía
7.
Int J Nanomedicine ; 16: 3041-3057, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33948084

RESUMEN

Background: The dentin exposure always leads to dentin hypersensitivity and/or caries. Given the dentin's tubular structure and low mineralization degree, reestablishing an effective biobarrier to stably protect dentin remains significantly challenging. This study reports a versatile dentin surface biobarrier consisting of a mesoporous silica-based epigallocatechin-3-gallate (EGCG)/nanohydroxyapatite delivery system and evaluates its stability on the dentinal tubule occlusion and the Streptococcus mutans (S. mutans) biofilm inhibition. Materials and Methods: The mesoporous delivery system was fabricated and characterized. Sensitive dentin discs were prepared and randomly allocated to three groups: 1, control group; 2, casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) group; and 3, the mesoporous delivery system group. The dentin permeability, dentinal tubule occlusion, acid and abrasion resistance, and S. mutans biofilm inhibition were determined for 1 week and 1 month. The in vitro release profiles of EGCG, Ca, and P were also monitored. Results: The mesoporous delivery system held the ability to sustainably release EGCG, Ca, and P and could persistently occlude dentinal tubules with acid and abrasion resistance, reduce the dentin permeability, and inhibit the S. mutans biofilm formation for up to 1 month compared with the two other groups. The system provided prolonged stability to combat oral adverse challenges and served as an effective surface biobarrier to protect the exposed dentin. Conclusion: The establishment of the dentin surface biobarrier consisting of a mesoporous delivery system indicates a promising strategy for the prevention and the management of dentin hypersensitivity and caries after enamel loss.


Asunto(s)
Biopelículas/crecimiento & desarrollo , Dentina/química , Streptococcus mutans/fisiología , Ácidos , Adsorción , Biopelículas/efectos de los fármacos , Calcio/análisis , Caseínas/farmacología , Catequina/análogos & derivados , Catequina/química , Catequina/farmacología , Muerte Celular/efectos de los fármacos , Recuento de Colonia Microbiana , Pulpa Dental/citología , Humanos , Nanopartículas/química , Nanopartículas/ultraestructura , Nitrógeno/química , Permeabilidad , Fósforo/análisis , Porosidad , Dióxido de Silicio/química , Streptococcus mutans/ultraestructura
8.
Arch Oral Biol ; 127: 105148, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-34022546

RESUMEN

OBJECTIVE: The aim of this study was to synthesize and characterize an experimental primer containing cationic lipid nanoparticles (NPL-chitosan) and to evaluate its properties. DESIGN: The NPL-chitosan were synthesized by emulsion and sonication method. The experimental primers were applied in dentin surface of fifty human molars. The experimental groups were: 1) application of commercial primer; 2) Primer containing 2% of Chlorhexidine (CHX) 3); Primer with 2% NPL-chitosan 4); Primer with 0.6 % of NPL-chitosan 5); Primer with 0.4 % of NPL-chitosan. A composite resin plateau was used for the analysis, where sections were made for making the dentin beams. The effect of experimental primer with cationic nanoparticles in the inhibition of matrix metalloproteinase (MMP) activity was carrying out by in situ zymography. For the Resin-Dentin Adhesive Strength and in situ Zymography analysis, was used the One-way analysis of variance (ANOVA) with significance level of 95 %. RESULTS: Spherical NPL-chitosan presented size below 220 nm, polydispersity index of 0.179 and zeta potential positive and was stable over 75 days. These nanoparticles showed antibacterial activity agsainst S. mutans with MIC of the 0.4 % and MBC of 0.67 %. In the Microtensile Strength, no statistical difference was observed between the experimental groups (p = 0.9054). The in situ zymography assay showed that the group with 2% of NPL-chitosan presented higher inactivation activity of MMPs compared to the other groups (p < 0.05). CONCLUSION: The experimental primer containing NPL-chitosan has antimicrobial activity, does not alter the adhesive resistance and inactivates MMPs present in dentin.


Asunto(s)
Quitosano , Recubrimiento Dental Adhesivo , Nanopartículas , Resinas Compuestas , Cementos Dentales/farmacología , Dentina , Recubrimientos Dentinarios , Humanos , Ensayo de Materiales , Metaloproteasas , Cementos de Resina , Resistencia a la Tracción
9.
J Appl Oral Sci ; 29: e20200859, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33886942

RESUMEN

INTRODUCTION: Due to its ability to arrest untreated dental caries, silver diamine fluoride (SDF) has been advocated for indirect pulp capping procedures. However, the high concentrations of silver and fluoride in SDF raise concerns about its biocompatibility to pulpal tissues. OBJECTIVES: This study aimed to investigate the effect of SDF on the viability, alkaline phosphatase (ALP) activity, and morphology of pulpal-like cells (RPC-C2A) and to evaluate the influence of reduced glutathione (GSH) on SDF-induced cytotoxicity and deposit formation on dentin. METHODOLOGY: The cytotoxicity of diluted 38% SDF solutions (10-4 and 10-5), with or without the addition of 5 mM or 50 mM GSH, was evaluated at 6 and 24 hours. Cell viability was detected using WST-8 and the effect on ALP activity was performed using an ALP assay kit. Cell morphology was observed using a phase-contrast microscope. Scanning electron microscopy analysis was conducted to evaluate the effect of GSH incorporation or conditioning on SDF-induced deposit formation on dentin discs. Cytotoxicity data were analyzed by two-way analysis of variance (ANOVA) and Tukey post hoc tests (p<0.05). RESULTS: There were significant differences between the groups. The results demonstrated that all tested SDF dilutions caused a remarkable cytotoxic effect, while the addition of GSH prevented SDF-induced damage at 6-hour exposure time in the higher dilution of SDF. Dentin treated with plain SDF or GSH-incorporated SDF solution showed deposit formation with occluded dentinal tubules, unlike the other groups. CONCLUSION: SDF severely disturbed the viability, mineralization-ability, and morphology of pulpal-like cells, while controlled concentrations of GSH had a short-term protective effect against SDF-induced damage. GSH showed an inhibitory effect on SDF-induced dentinal deposit formation. Further research is warranted to evaluate the effect of GSH on caries-arresting, anti-hypersensitivity, and antibacterial functions of SDF.


Asunto(s)
Caries Dental , Animales , Cariostáticos/toxicidad , Dentina , Fluoruros Tópicos/toxicidad , Glutatión , Compuestos de Amonio Cuaternario , Ratas , Compuestos de Plata
10.
Oper Dent ; 46(1): 75-86, 2021 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-33882135

RESUMEN

CLINICAL RELEVANCE: Post and core crowns and endocrowns perform similarly on fracture strength, but endocrowns have more repairable fractures.


Asunto(s)
Incisivo , Técnica de Perno Muñón , Coronas , Cementos Dentales , Fracaso de la Restauración Dental , Análisis del Estrés Dental , Dentina
11.
Oper Dent ; 46(1): E1-E10, 2021 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-33882142

RESUMEN

CLINICAL RELEVANCE: Carious and eroded dentin represent clinical challenges. The use of a universal bonding system, in a self-etching mode, associated with chlorhexidine (CHX) seems to not improve its longevity. This may be attributed to the competition for calcium between the bonding agent functional monomer and CHX.


Asunto(s)
Clorhexidina , Recubrimiento Dental Adhesivo , Cementos Dentales , Dentina , Recubrimientos Dentinarios , Ensayo de Materiales , Cementos de Resina , Resistencia a la Tracción
12.
Br Dent J ; 230(7): 386-387, 2021 04.
Artículo en Inglés | MEDLINE | ID: mdl-33837313
13.
Pol Merkur Lekarski ; 49(290): 153-157, 2021 Apr 18.
Artículo en Inglés | MEDLINE | ID: mdl-33895765

RESUMEN

The greatest challenge of modern implantology is the loss of bone tissue in esthetic region of maxilla and mandible. Significant bone changes caused for example by cysts, unerupted teeth or traumatic extraction often provoke bilateral or trilateral bone defects. Thanks to the possibility of applying demineralized dentin and dentin blocks gained from extracted teeth of the patient, it is possible to successfully regenerate bone tissue especially in the esthetic zone. AIM: The aim of the study was to present a case of a patient who underwent bone augmentation for implantation. In addition, a review of the literature illustrating the effectiveness of autogenous bone graft material derived from ground teeth in augmentation procedures was performed. A CASE REPORT: The paper presents a case of a 26-year-old man in whom bone defect was augmented with material derived from dentin blocks and partially demineralized dentin processed in the BonMaker device after extraction of the root of tooth 11. A systematic review of literature was conducted analyzing articles published between 1975 and 2020. From 80 articles, 25 were selected for this study. CONCLUSIONS: The presented case and the systematic review of literature indicate that tooth-derived bone graft material prepared from extraction can effectively restore alveolar bone defect. The results we get so far are very satisfying. Further studies should be performed to confirm the osteogenic effects and safety use of this tooth based graft material.


Asunto(s)
Regeneración Ósea , Dentina , Adulto , Humanos , Masculino , Mandíbula , Extracción Dental/efectos adversos
14.
J Adhes Dent ; 23(2): 159-165, 2021 Apr 07.
Artículo en Inglés | MEDLINE | ID: mdl-33825429

RESUMEN

PURPOSE: To evaluate the effect of inclusion of two dimethyl sulfoxide (DMSO) concentrations in simplified etch-and-rinse adhesives on dentin bonding durability after three years of water storage. MATERIALS AND METHODS: Forty-two caries-free third molars were divided into six experimental groups (n = 7) according to the following factors: 1) adhesive (Adper Single Bond 2 [SB], 3M Oral Care; Prime&Bond 2.1 [PB], Dentsply Sirona); 2) concentration of DMSO (control group: 0.0% DMSO; addition of 0.2% DMSO [0.2] and 2% DMSO [2.0]). After completing restoration, specimens were stored in water (37°C) for 24 h, sectioned into adhesive-dentin sticks (0.8 mm2), tested for microtensile bond strength (µTBS) at 0.5 mm/min, and examined for nanoleakage (NL) using SEM immediately thereafter or after three years of water storage. Data were subjected to a three-way repeated-measures ANOVA and Tukey's test (α = 0.05) for each property evaluated. RESULTS: After three years of water storage, for both adhesives, the incorporation of 2% DMSO maintained the µTBS when compared to immediate µTBS (p > 0.05). In general, SB resulted in a statistically significantly higher mean of µTBS compared to PB, independent of the DMSO concentration after water storage (p < 0.05). Furthermore, the amount of NL was lower and practically limited to the hybrid layer given the concentrations of 0.2% and 2% DMSO for both tested adhesives after three years. CONCLUSION: The incorporation of DMSO in simplified etch-and-rinse adhesives maintains the long-term stability of the dentin bond.


Asunto(s)
Recubrimiento Dental Adhesivo , Recubrimientos Dentinarios , Dentina , Dimetilsulfóxido , Ensayo de Materiales , Cementos de Resina , Resistencia a la Tracción , Agua
15.
J Adhes Dent ; 23(2): 167-175, 2021 Apr 07.
Artículo en Inglés | MEDLINE | ID: mdl-33825430

RESUMEN

PURPOSE: To investigate the effects of root canal irrigants, dentin surface treatment, and timing of the restoration on the microtensile bond strength (µTBS) of a universal adhesive to deep coronal dentin. MATERIALS AND METHODS: Ninety (90) intact molars were grouped according to the irrigation protocol: group 0 (saline, control group); group 1: 5.25% sodium hypochlorite (NaOCl), 17% ethylenediaminetetraacetic acid (EDTA) followed by 5.25% NaOCl; group 2: 18% etidronic acid (HEDP) + 5.25% NaOCl in a single mixture. Groups 1 and 2 were divided into 2 subgroups (n = = 10) according to the time of restoration: immediate (subgroup A) and after 7 days (subgroup B). Four other groups (n = 10) were created according to the dentin surface pretreatment and received an immediate restoration: group 3: 5.25% NaOCl - 17% EDTA and AH Plus Cleaner; group 4: 5.25% NaOCl - 17% EDTA and 100% ethanol; group 5: 5.25% NaOCl + 18% HEDP and AH Plus Cleaner; group 6: 5.25% NaOCl + 18% HEDP and 100% ethanol. µTBS testing was carried out for each subgroup and interfaces were analyzed through SEM. The µTBS was analyzed with Welch statistics and the post-hoc Games-Howell test for multiple comparisons (p < 0.05). RESULTS: Statistically significant differences were observed between test groups and control groups (p < 0.001), except for group 3 (p = 0.349). No significant differences were recorded between groups 1A (27.5 ± 8.7 MPa), 2A (32.6 ± 14.5 MPa) and 3 (27.3 ± 14.3 MPa). Group 6 (48.6 ± 11.6 MPa) exhibited the highest µTBS among all tested groups. For groups 1 and 2, significantly higher values were recorded for subgroups 1B (39.3 ± 7.6 MPa) and 2B (43.8 ± 8.3 MPa) compared to subgroups 1A (27.5 ± 8.7 MPa) and 2A (32.6 ± 14.5 MPa). CONCLUSION: When using NaOCl as root canal irrigant, it is advisable to delay the placement of a post-endodontic-treatment restoration.


Asunto(s)
Recubrimiento Dental Adhesivo , Cementos Dentales , Cavidad Pulpar , Análisis del Estrés Dental , Dentina , Ácido Edético , Ensayo de Materiales , Irrigantes del Conducto Radicular , Preparación del Conducto Radicular , Hipoclorito de Sodio
16.
J Appl Oral Sci ; 29: e20200266, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33825761

RESUMEN

OBJECTIVES: We analyzed the effects of the Er:YAG laser used with different parameters on dentinal tubule (DT) occlusion, intrapulpal temperature and pulp tissue morphology in order to determine the optimal parameters for treating dentin hypersensitivity. METHODOLOGY: Dentin specimens prepared from 36 extracted human third molars were randomized into six groups according to the treatment method (n=6 each): control (A); Gluma desensitizer (B); and Er:YAG laser treatment at 0.5 W , 167 J/cm2 (50 mJ, 10 Hz) (C), 1 W , 334 J/cm2 (50 mJ, 20 Hz) (D), 2 W , 668 J/cm2 (100 mJ, 20 Hz) (E), and 4 W and 1336 J/cm2 (200 mJ, 20 Hz) (F). Treatment-induced morphological changes of the dentin surfaces were assessed using scanning electron microscopy (SEM) to find parameters showing optimal dentin tubule occluding efficacy. To further verify the safety of these parameters (0.5 W, 167 J/cm2), intrapulpal temperature changes were recorded during laser irradiation, and morphological alterations of the dental pulp tissue were observed with an upright microscope. RESULTS: Er:YAG laser irradiation at 0.5 W (167 J/cm2) were found to be superior in DT occlusion, with an exposure rate significantly lower than those in the other groups (P<0.05). Intrapulpal temperature changes induced by Er:YAG laser irradiation at 0.5 W (167 J/cm2) with (G) and without (H) water and air cooling were demonstrated to be below the threshold. Also, no significant morphological alterations of the pulp and odontoblasts were observed after irradiation. CONCLUSION: Therefore, 0.5 W (167 J/cm2) is a suitable parameter for Er:YAG laser to occlude DTs, and it is safe to the pulp tissue.


Asunto(s)
Láseres de Estado Sólido , Oclusión Dental , Dentina , Humanos , Láseres de Estado Sólido/uso terapéutico , Microscopía Electrónica de Rastreo
17.
Gen Dent ; 69(3): 37-41, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33908876

RESUMEN

This in vitro study aimed to evaluate the influence of endodontic irrigation solutions and resin sealing of the dentin surfaces of the cavity before irrigation on the fracture strength (FS) of maxillary premolars. Seventy-two human maxillary premolars were randomly assigned to 6 groups (n = 12). Group 1 consisted of intact teeth that served as negative controls. In groups 2 to 6, root canal treatment was performed after mesio-occlusal preparation. In group 6, the dentin surfaces of the mesio-occlusal cavity were sealed with a self-adhesive flowable composite resin before instrumentation and irrigation of the canal. The volume and contact time of the irrigation solutions used during endodontic treatment of groups 2, 4, 5, and 6 were standardized as follows: 2 mL of 5.25% sodium hypochlorite (NaOCl) for 1 minute after each file, 5 mL of 17% ethylenediaminetetraacetic acid (EDTA) for 3 minutes after instrumentation was completed, and 5 mL of 5.25% NaOCl for 1 minute as the final irrigation. In group 3, the irrigation solution was normal saline solution only. After root canal obturation, in group 2, the cavities were left unrestored as a positive control. In groups 3 (saline-rinsed), 4 (conventionally restored), and 6 (presealed), the restorations were carried out with an etch-and-rinse adhesive and composite resin immediately after root canal obturations. In group 5 (delay-restored), the restorations were carried out with an etch-and-rinse adhesive and composite resin after a 1-week delay. After thermomechanical cycling, the teeth were subjected to FS testing under continuous compressive force. Data were analyzed with 1-way analysis of variance and Tukey tests. The unrestored group, which demonstrated the lowest FS, did not differ significantly from the conventionally restored group; the FS of both groups was significantly lower than that in the other groups (P ≤ 0.001). The presealed group exhibited the highest FS (P ≤ 0.02). The FS values of the saline and delay-restored groups were statistically comparable. In the present study, NaOCl/EDTA irrigation had an adverse effect on the FS. Presealing of the dentin surfaces of the cavity with self-adhesive flowable composite resin significantly increased the FS of aged composite resin-restored premolars.


Asunto(s)
Restauración Dental Permanente , Fracturas de los Dientes , Anciano , Diente Premolar , Resinas Compuestas , Análisis del Estrés Dental , Dentina , Resistencia Flexional , Humanos , Ensayo de Materiales , Fracturas de los Dientes/prevención & control
18.
J Mech Behav Biomed Mater ; 119: 104385, 2021 07.
Artículo en Inglés | MEDLINE | ID: mdl-33823357

RESUMEN

OBJECTIVES: The aim of this study was to assess the fatigue loading behavior and fracture resistance of endodontically treated teeth restored with adhesively luted bundled fiber posts in comparison to solid fiber posts. Image analysis (2D and 3D) was applied to evaluate modes of failure and to characterize susceptible parts of the post-and-core interface. METHOD: Crowns of 72 human similar-sized central upper incisors were removed and roots received a conventional root canal filling prior to establishing 4 groups of core build-up: No Post group (nP) received a 4 mm deep filling made of composite inside the canal with no dental post, fiber post group (FP) received a conventional solid post, and two experimental groups received bundles of 6 (FB6) or 12 (FB12) 0.3 mm thin fiber posts, respectively. Posts were placed adhesively inside the root canal using a dual-curing build-up composite in combination with a self-etch adhesive, the latter was also used for nP group. Upon completion of core build-ups, all teeth received full-ceramic crowns that recreated the original tooth form. Samples were subjected in a 135° angle to thermo-mechanical loading (TML) for 1.2 Mill. chewing cycles followed by static load tests (fracture resistance). Fracture modes as well as intracanal failure modes with respect to failed interfaces were analyzed using optical and electron microscopy (SEM). Microcomputer tomography (µCT) was used to exemplary compare pre and post TML geometries. RESULTS: Static load test was significantly different between groups (p < 0.0005; Kruskal-Wallistest). Pairwise comparison showed that the nP group (221 ± 103N) failed at significantly lower forces compared to the FP (454 ± 184N), FB6 (477 ± 250N) and FB12 (478 ± 260N) groups (p ≤ 0,001; Mann-Whitney-U-test). Fracture modes were significantly affected by the presence or absence of a post (p ≤ 0,016; Chi-square test) revealing increased incidence of restorable fractures at the cervical region for nP group. Microscopic analysis revealed more intracanal failures at interfaces between post surfaces and composite for solid posts, whereas fiber bundled posts mostly failed at the interfaces between composite and dentin. Micro-CT analysis showed no alterations of the root-post-and-core structure after TML except slight deformations of occasionally entrapped voids. CONCLUSION: Fracture resistance and fracture modes were significantly affected by the presence or absence of a post, whereas the investigated post groups did not differ from each other. However intracanal failure revealed differences in adhesive failures between solid fiber posts and bundled fiber posts. Deformations of entrapped voids, revealed by micro-Ct analyses after TML, lead to the assumption that applied forces result in alterations in the regions of voids.


Asunto(s)
Técnica de Perno Muñón , Fracturas de los Dientes , Resinas Compuestas , Cavidad Pulpar , Análisis del Estrés Dental , Dentina , Fatiga , Vidrio , Humanos
19.
J Mech Behav Biomed Mater ; 119: 104498, 2021 07.
Artículo en Inglés | MEDLINE | ID: mdl-33839538

RESUMEN

OBJECTIVE: In this study, we incorporated hybrid nanoparticles (poly (acrylic acid)-grafted nanoclay/nanosilica, respectively, with platelet and spherical morphologies, abbreviated as PAA-g-NC-Sil) in different concentrations (0, 0.2, 0.5, 1, 2 and 5 wt%) to an experimental dentin bonding system and investigated the physical properties of the filled adhesive and its shear bond strength (µ-SBS) to dentin. We subsequently compared the properties of the adhesives containing PAA-g-NC-Sil with previously studied adhesives containing poly (methacrylic acid)-g-nanoclay (PMA-g-NC) (Solhi et al., 2012a), poly (acrylic acid)-g-nanoclay (PAA-g-NC) (Solhi et al., 2012b), and the hybrid poly (methacrylic acid)-grafted-nanoclay-nanosilica (PMA-g-NC-Sil) (Solhi et al., 2020). MATERIALS AND METHODS: In a set of previous publications and the present paper, we grafted poly (acrylic acid) (PAA) or poly (methacrylic acid) (PMA) onto the surface of pristine Na-MMT nanoclay (Cloisite® Na+) through free radical polymerization of monomer in an aqueous media in the presence or absence of nanosilica particles. We characterized the resulting modified nanoparticles (PMA-g-NC, PAA-g-NC, PMA-g-NC-Sil and PAA-g-NC-Sil) using GPC, FTIR, TGA, and XRD. We then incorporated the modified particles as functionalized fillers to experimental dentin adhesives in different concentrations and studied the stability of modified fillers dispersion by separation analysis. We also studied the properties of the photo-cured adhesive matrices using FTIR, TEM, SEM, EDXA, and XRD. We examined the shear bond strength of the adhesives (containing different contents of each modified filler, separately) to human premolar teeth. The results were analysed and compared statistically. RESULTS: The results confirmed that the polymers have been grafted onto the surface of nanoclay. An exfoliated structure for the nanoclay platelets in the photo-cured adhesive containing PAA-g-NC-Sil was observed. Addition of 0.5 wt% of PAA-g-NC-Sil to the experimental adhesive increased the shear bond strength and the dispersion stability in comparison to unfilled adhesive. The same trend was also observed for adhesives containing PMA-g-NC, PAA-g-NC, and PMA-g-NC-Sil. The adhesive containing PAA-g-NC-Sil showed the best dispersion stability and subsequently the highest shear bond strength in the optimal concentration among adhesives containing the four available fillers (PMA-g-NC, PAA-g-NC, PMA-g-NC-Sil and PAA-g-NC-Sil). SIGNIFICANCE: Addition of poly (acrylic acid) modified nanoparticles to the experimental dentin adhesives resulted in higher shear bond strength due to the potential interactions between the carboxylic acid functional groups on the surface of the modified particles and the dentin structure. Between the poly (acrylic acid) and poly (methacrylic acid), the former acid with higher PKa performed better. Addition of the spherical nanosilica particles to the adhesives containing platelet nanoclay helped to better exfoliate the platelets resulting in improved µ-SBS and dispersion stability.


Asunto(s)
Recubrimiento Dental Adhesivo , Nanopartículas , Adhesivos , Cementos Dentales , Dentina , Recubrimientos Dentinarios , Humanos , Ensayo de Materiales , Polimerizacion , Cementos de Resina , Resistencia al Corte
20.
Artículo en Inglés | MEDLINE | ID: mdl-33808616

RESUMEN

In the literature, autogenous dentin is considered a possible alternative to bone substitute materials and autologous bone for certain indications. The aim of this proof-of-concept study was to use autogenous dentin for lateral ridge augmentation. In the present retrospective study, autogenous dentin slices were obtained from teeth and used for the reconstruction of lateral ridge defects (tooth-shell technique (TST): 28 patients (15 females, 13 males) with 34 regions and 38 implants). The bone-shell technique (BST) according to Khoury (31 patients (16 females, 15 males) with 32 regions and 41 implants) on autogenous bone served as the control. Implants were placed simultaneously in both cases. Follow-up was made 3 months after implantation. Target parameters during this period were clinical complications, horizontal hard tissue loss, osseointegration, and integrity of the buccal lamella. The prosthetic restoration with a fixed denture was carried out after 5 months. The total observation period was 5 months. A total of seven complications occurred. Of these, three implants were affected by wound dehiscences (TST: 1, BST: 2) and four by inflammations (TST: 0, BST: 4). There were no significant differences between the two groups in terms of the total number of complications. One implant with TST exhibited a horizontal hard tissue loss of 1 mm and one with BST of 0.5 mm. Other implants were not affected by hard tissue loss. There were no significant differences between the two groups. Integrity of the buccal lamella was preserved in all implants. All implants were completely osseointegrated in TST and BST. All implants could be prosthetically restored with a fixed denture 5 months after augmentation. TST showed results comparable to those of the BST. Dentin can therefore serve as an alternative material to avoid bone harvesting procedures and thus reduce postoperative discomfort of patients.


Asunto(s)
Aumento de la Cresta Alveolar , Sustitutos de Huesos , Trasplante Óseo , Dentina , Femenino , Estudios de Seguimiento , Humanos , Masculino , Estudios Retrospectivos
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...