RESUMO
AIM: To evaluate ex vivo the efficacy of 35% hydrogen peroxide for intracoronal bleaching when activated by LEDs, halogen lamp or by the walking bleach technique. METHODOLOGY: Forty extracted human maxillary central incisors had their crowns resected 1 mm below the amelo-cemental junction and were submitted to artificial staining in centrifuged rat haemolysed blood. A 2-mm thick glass ionomer cervical plug was placed inside the canal, at the level of the amelo-cemental junction. Samples were divided randomly into five groups: group I received 35% hydrogen peroxide gel activated by LEDs. Group II received 35% hydrogen peroxide gel activated by a halogen lamp-based light curing unit. Group III received 35% hydrogen peroxide gel followed by the walking bleach technique. Group IV was neither artificially stained nor bleached (positive control) and group V was stained, but not bleached (negative control). The shade of the teeth was assessed visually by three independent and calibrated evaluators, before and after bleaching. The results were analysed using Kruskal-Wallis one-way analysis of variance and Dunn's post-test. RESULTS: No statistical differences regarding sample shades were found amongst groups for the tested internal bleaching techniques (P > 0.05). CONCLUSIONS: Hydrogen peroxide for intracoronal bleaching when activated either by LEDs, halogen lamp or by the walking bleach technique presented similar efficacy.
Assuntos
Clareamento Dental/métodos , Descoloração de Dente/tratamento farmacológico , Adulto , Idoso , Análise de Variância , Animais , Sangue , Halogênios , Humanos , Peróxido de Hidrogênio/uso terapêutico , Incisivo , Luz , Masculino , Pessoa de Meia-Idade , Oxidantes/uso terapêutico , Ratos , Semicondutores , Dente não VitalRESUMO
AIM: To investigate the influence of cervical preflaring with different instruments (Gates-Glidden drills, Quantec Flare series instruments and LA Axxess burs) on the first file that binds at working length (WL) in maxillary central incisors. METHODOLOGY: Forty human maxillary central incisors with complete root formation were used. After standard access cavities, a size 06 K-file was inserted into each canal until the apical foramen was reached. The WL was set 1 mm short of the apical foramen. Group 1 received the initial apical instrument without previous preflaring of the cervical and middle thirds of the root canal. Group 2 had the cervical and middle portion of the root canals enlarged with Gates-Glidden drills sizes 90, 110 and 130. Group 3 had the cervical and middle thirds of the root canals enlarged with nickel-titanium Quantec Flare series instruments. Titanium-nitrite treated, stainless steel LA Axxess burs were used for preflaring the cervical and middle portions of root canals from group 4. Each canal was sized using manual K-files, starting with size 08 files with passive movements until the WL was reached. File sizes were increased until a binding sensation was felt at the WL, and the instrument size was recorded for each tooth. The apical region was then observed under a stereoscopic magnifier, images were recorded digitally and the differences between root canal and maximum file diameters were evaluated for each sample. RESULTS: Significant differences were found between experimental groups regarding anatomical diameter at the WL and the first file to bind in the canal (P < 0.01, 95% confidence interval). The major discrepancy was found when no preflaring was performed (0.151 mm average). The LA Axxess burs produced the smallest differences between anatomical diameter and first file to bind (0.016 mm average). Gates-Glidden drills and Flare instruments were ranked in an intermediary position, with no statistically significant differences between them (0.093 mm average). CONCLUSIONS: The instrument binding technique for determining anatomical diameter at WL is not precise. Preflaring of the cervical and middle thirds of the root canal improved anatomical diameter determination; the instrument used for preflaring played a major role in determining the anatomical diameter at the WL. Canals preflared with LA Axxess burs created a more accurate relationship between file size and anatomical diameter.
Assuntos
Instrumentos Odontológicos , Cavidade Pulpar/anatomia & histologia , Odontometria/métodos , Preparo de Canal Radicular/instrumentação , Ápice Dentário/anatomia & histologia , Análise de Variância , Ligas Dentárias , Humanos , Incisivo , Maxila , Níquel , Preparo de Canal Radicular/métodos , Aço Inoxidável , Titânio , Colo do DenteRESUMO
AIM: To evaluate the effect of 15% EDTAC solution and Er:YAG laser irradiation on the adhesiveness to dentine of root canal sealers containing calcium hydroxide. METHODOLOGY: The crowns of 60 maxillary human molars were ground until dentine was exposed. The teeth were divided into three groups of 20 teeth: group I, the dentine surface received no treatment; group II, 15% EDTAC solution was applied to the dentine; group III, the dentine received Er:YAG laser application (11 mm focal distance with perpendicular incidence to dentine surface; 4 Hz frequency; 200 mJ energy; 2.25 W potency; 62 J total energy; 1 min application time). Aluminium cylinders filled with the sealers, Sealer 26, Apexit, Sealapex and CRCS, were then applied to the treated surfaces. Adhesiveness was measured with a universal testing machine, with traction results given in MegaPascals (MPa). These results were submitted to anova tests. RESULTS: Statistical analysis showed significant differences (P < 0.01) amongst adhesiveness values of the sealers and treatments tested. Thus, sealers could be ranked in decreasing adhesiveness values: Sealer 26, CRCS, Apexit, Sealapex. Er:YAG laser irradiation and EDTAC solution application increased adhesiveness values only for Sealer 26 and Apexit. Laser irradiation was superior to EDTAC application only for Sealer 26 adhesiveness values. CONCLUSIONS: Er:YAG laser is as efficient as EDTAC solution in increasing adhesiveness of root canal sealers containing calcium hydroxide to human dentine.
Assuntos
Hidróxido de Cálcio/química , Quelantes/farmacologia , Colagem Dentária , Dentina/ultraestrutura , Ácido Edético/análogos & derivados , Ácido Edético/farmacologia , Lasers , Materiais Restauradores do Canal Radicular/química , Adesividade , Silicatos de Alumínio , Análise de Variância , Bismuto/química , Dentina/efeitos dos fármacos , Dentina/efeitos da radiação , Érbio , Humanos , Teste de Materiais , Salicilatos/química , Estresse Mecânico , Propriedades de Superfície , Ítrio , Óxido de Zinco/químicaRESUMO
AIM: To evaluate smear layer removal by different irrigating solutions under ultrasonic agitation. METHODOLOGY: Twenty recently extracted mandibular incisors with a single root canal were divided into four equal groups. Three groups were instrumented using the modified double-flared technique, the fourth remained unprepared. Each group was irrigated with either distilled water, 1.0% sodium hypochlorite alone or associated with 15% EDTAC between each file size. The final group was not instrumented but irrigated with 1.0% sodium hypochlorite and 15% EDTAC. A size 15 file energised by ultrasound was used with small amplitude filing movements against the canal walls in all groups. The teeth were split longitudinally and the roots measured to provide three sections of the same size (cervical, middle and apical). Samples were examined under the scanning electron microscope and assessed for the amount of smear layer by three independent and calibrated examiners. The scoring system ranged from 1 (no smear layer) to 4 (all areas covered by smear layer). Due to the non-parametric nature of the data, Friedman's test was used for statistical analysis. RESULTS: Canal walls were covered with smear layer in the group irrigated with 1% sodium hypochlorite alone and the group irrigated with distilled water. Canals irrigated with 1.0% sodium hypochlorite associated with 15% EDTAC had less smear layer throughout the canal (P < 0.001). There were no statistical differences for the amount of smear layer found on the cervical, middle and apical thirds when each group was analysed separately. CONCLUSIONS: Under ultrasonic agitation, sodium hypochlorite associated with EDTAC removed the smear layer from root canal walls, whereas irrigation with distilled water or 1.0% sodium hypochlorite alone did not remove smear layer.
Assuntos
Ácido Edético/análogos & derivados , Ácido Edético/uso terapêutico , Irrigantes do Canal Radicular/uso terapêutico , Camada de Esfregaço , Hipoclorito de Sódio/uso terapêutico , Terapia por Ultrassom , Cavidade Pulpar/efeitos dos fármacos , Cavidade Pulpar/ultraestrutura , Dentina/efeitos dos fármacos , Dentina/ultraestrutura , Combinação de Medicamentos , Ácido Edético/administração & dosagem , Humanos , Incisivo , Microscopia Eletrônica de Varredura , Variações Dependentes do Observador , Preparo de Canal Radicular/instrumentação , Preparo de Canal Radicular/métodos , Hipoclorito de Sódio/administração & dosagem , Estatísticas não Paramétricas , ÁguaRESUMO
The effect of Er:YAG laser application and EDTAC on the adhesion of epoxy resin-based endodontic sealers to human dentin was evaluated in vitro. A total of 99 extracted human maxillary molars with their crowns worn flat were used. The teeth were divided into 3 groups: group 1, the dentin surface received no treatment; group 2, EDTAC was applied to the dentin surface for 5 min; group 3, the dentin surface received Er:YAG laser application (2.25 W potency; 11 mm focal distance; 4 Hz frequency; 200 mJ energy; 62 J total energy; 313 mean impulse). Three teeth from each group were analyzed by scanning electron microscopy for changes in dentin surface. The epoxy resin root canal sealers used were: AH Plus, Topseal, Sealer 26, AH 26, and Sealer Plus. The zinc oxide eugenol-based sealer Fillcanal was used as control. Adhesion was measured with a Universal testing machine. The results showed a statistically significant difference at the level of 1% among the dentin treatments. The dentin treated with Er:YAG laser showed greater adhesion with the sealers than dentin treated with EDTAC which was greater than dentin that received no treatment. The Tukey test showed the formation of 5 groups in decreasing order of adhesion: AH Plus, Topseal and Sealer 26, AH 26, Sealer Plus, and Fillcanal (Grossman cement).
Assuntos
Quelantes/uso terapêutico , Colagem Dentária , Dentina/ultraestrutura , Ácido Edético/análogos & derivados , Ácido Edético/uso terapêutico , Resinas Epóxi/química , Terapia a Laser , Materiais Restauradores do Canal Radicular/química , Adesivos/química , Silicatos de Alumínio , Bismuto/química , Hidróxido de Cálcio/química , Dentina/efeitos dos fármacos , Dentina/efeitos da radiação , Combinação de Medicamentos , Érbio , Humanos , Metenamina/química , Microscopia Eletrônica de Varredura , Prata/química , Titânio/química , Ítrio , Cimento de Óxido de Zinco e Eugenol/químicaRESUMO
With the development of rotary nickel-titanium files and their applications in Endodontics, the concepts of root canal preparation have changed. The objective of this research is to evaluate the transportation of simulated root canals caused by stainless steel ENDOflash rotary files compared to nickel-titanium ProFile files (.04, .06 and Orifice Shapers). Twenty-four simulated root canals with a 30 degrees curvature were randomly divided into 2 groups and prepared with ENDOflash or ProFile files according to manufacturers' instructions. Comparison between the simulated root canals before and after instrumentation showed significant differences (p < 0.001) between the groups, with greater transportation observed with ENDOflash files. One case of deformation was observed with a ProFile instrument (#20/.04) and there were no fractures.
Assuntos
Cavidade Pulpar/anatomia & histologia , Preparo de Canal Radicular/instrumentação , Ligas Dentárias , Desenho de Equipamento , Falha de Equipamento , Humanos , Processamento de Imagem Assistida por Computador , Modelos Anatômicos , Níquel , Rotação , Aço Inoxidável , Estatísticas não Paramétricas , Titânio , TorqueRESUMO
In the present study, the effect of aged eugenol (up to 180 days) on the flow, setting time and adhesion of Grossman root canal sealer was evaluated, following the American Dental Association specification number 57 for root canal sealers. An Instron Universal testing machine 4444 was used for testing adhesion. There were statistically significant differences between groups, with a higher flow, lower setting time and adhesion for aged eugenol. It can be concluded that time affects eugenol, with consequent effects on Grossman sealer.
Assuntos
Eugenol/química , Materiais Restauradores do Canal Radicular/química , Cimento de Óxido de Zinco e Eugenol/química , Adesividade , Sulfato de Bário/química , Bismuto/química , Boratos/química , Carbonatos/química , Colagem Dentária , Análise do Estresse Dentário/instrumentação , Humanos , Resinas Vegetais/química , Reologia , Estresse Mecânico , Fatores de Tempo , Óxido de Zinco/químicaRESUMO
The external and internal anatomy of 269 third molars (155 maxillary and 114 mandibular) were studied. The teeth were measured, classified according to their root number and shape and the internal anatomy was observed by the use of diaphanization. A great anatomical variability was found, with the presence of up to 5 roots in maxillary third molars and 3 roots in mandibular third molars. The number of root canals followed the same pattern.