Preparación Ultrasónica del Espacio Protésico y su Influencia en la Resistencia Adhesiva de Postes de Fibroresina en Conductos Ovalados / Ultrasonic Preparation of the Prosthetic Space and its Influence on the Bond Strength of Fiber Post in Oval-Shaped Canals

RESUMEN: Paredes sin instrumentar y con material obturador endodóntico residual pueden elevar la posibilidad de la falla adhesiva de postes de fibroresina. Las fresas de desobturación y conformación del espacio protésico poseen una sección circular, lo que dificulta una adecuada preparación y limpieza de las paredes de los conductos ovales. El objetivo del presente estudio fue evaluar la capacidad de limpieza ultrasónica del espacio protésico y cómo ésta influyó en la resistencia a la tracción de postes de fibroresina en conductos ovales. Se utilizaron 30 premolares con conducto ovalado divididos aleatoriamente en 3 grupos de estudio (n=10), siendo: grupo A: preparación rotatoria con complemento ultrasónico, grupo B: preparación rotatoria y grupo C: grupo control. Postes de fibra de vidrio fueron cementados y luego de 7 días se realizaron cortes de un milímetro de grosor del tercio cervical y medio de cada muestra y se evaluó microscópicamente el área de gutapercha remanente y área efectiva de adhesión. Estos fueron sometidos a una prueba de push out evaluando la resistencia adhesiva de los postes. Finalmente fueron observados microscópicamente para analizar tipo de falla. Los resultados se analizaron mediante el test de ANOVA, Bonferroni, Kruskal-Wallis y Mann Whitney (p < 0.05), registrando diferencias estadísticamente significativas en la resistencia a tracción, área de gutapercha remanente y área disponible para la adhesión; además de una relación directa entre gutapercha remanente y menor resistencia a la tracción. Conclusiones: La preparación ultrasónica del espacio protésico aumenta la resistencia a la tracción de postes de fibroresinas cementados en conductos ovalados.

ABSTRACT: Untouched canal walls with residual filling materials can increase the probability of adhesive failure of fiber posts. The drills used for desobturation and conformation of the prosthetic space, has a circular cross section, which does not allow a proper preparation and cleaning of oval-shaped canal walls. The objective of the study was to evaluate the ultrasonic cleaning of the prosthetic space and how this influences the adhesive strength of fiber posts in oval-shaped canals. Thirty (30) oval-shaped canal premolars were randomly divided into 3 groups (n = 10): Group A: rotary desobturation with ultrasonic complement, group B: rotary desobturation without ultrasonic complement and group C: control group. Fiberglass posts were cemented; after 7 days, one-millimeter slices were performed, one of the cervical and another from the middle third of the root. The slices were analyzed under an optical microscope to evaluate remaining gutta percha and effective adhesion area. Samples were subjected to a push-out test to evaluate bond strength of the fiber resin posts. Finally, samples were evaluated microscopically to analyze the type of failure. The results were analyzed using ANOVA, Bonferroni, KruskalWallis and Mann Whitney test (p < 0.05), recording statistically significant differences in bond strength, remaining gutta-percha area and clean walls for adhesion; In addition, to a direct relationship between remaining gutta percha and lower adhesive strength, the ultrasonic preparation of the prosthetic space increases bond strength of fiber posts in oval canals.

Apical displacement and residual root canal filling with single-cone after post space preparation: a micro-ct analysis

Abstract The purpose of this study was to evaluate the presence of residues after post space preparation (PSP) and establish whether the apical displacement of the gutta-percha was affected by the moments and methods of PSP in teeth filled by the single-cone technique. The root canals of 20 bovine incisor teeth were instrumented with Reciproc and filled with single-cone and AH Plus. The specimens were divided into 4 groups according to the moment and method of PSP (n=5): immediate with drill, immediate with thermoplasticizer, delayed with drill and delayed with thermoplasticizer. Micro-CT scans were performed before and after the PSP for residues of the root canal filling (1) and analysis of apical displacement (2). Data were analyzed by using 2-way repeated measurement ANOVA (1) and 2-way ANOVA (2) followed by the Tukey's test (a=0.05). Significance effect on the residues percentage remaining for methods (p=0.044), for moments (p=0.006), for thirds repetition (p<0.001), and for interaction between methods and thirds (p<0.001), and moments and thirds (p=0.044). Significance effect on the apical displacement of root canal filing was detected for methods (p=0.008), however no difference was found between moments (p=0.617). In general, PSP using drill resulted in more homogeneous root canal preparation, mainly when made immediately. For all other combinations between methods and moments for PSP, the middle and apical thirds presented significant higher residues remaining. Thermo method performed in both moments and the drill method performed immediately had displacement in the apical direction, representing extrusion of the root filling material.

Resumo O objetivo deste estudo foi avaliar a presença de resíduos após o alívio do canal (AC) e verificar se o deslocamento apical da guta-percha foi afetado pelos momentos e métodos de AC em dentes obturados pela técnica do cone único. Os canais radiculares de 20 dentes incisivos bovinos foram instrumentados com Reciproc e obturados com cone único e AH Plus. As amostras foram divididas em 4 grupos de acordo com o momento e método de AC (n=5): broca imediato, termocompactador imediato, broca tardio e termocompactador tardio. Escaneamentos em micro-CT foram realizados antes e após o AC para análise dos resíduos da obturação (1) e do deslocamento apical (2). Os dados foram analisados empregando ANOVA em 2 fatores com medida repetida (1), ANOVA em dois fatores (2), seguidas do teste de Tukey (α=0,05). A porcentagem de resíduos remanescentes foi influenciada pelos métodos (p=0,044), momentos (p=0,006), pelo fator de repetição terços do canal (p<0,001), e pelas interações entre métodos e terços (p<0,001), e momentos e terços (p=0,044). Já para o deslocamento apical da obturação do canal radicular foi detectada influência significativa para os métodos (p=0,008), no entanto, nenhuma diferença foi encontrada entre os momentos (p=0,617). Em geral, AC usando brocas resultou em preparo mais homogêneo dos canais radiculares, principalmente quando realizado imediatamente após a obturação. Para todas as outras combinações entre métodos e momentos de AC, o terço médio e apical apresentaram significativamente maiores resíduos remanescentes. O método termo realizado nos dois momentos e o método broca de preparo realizado imediatamente resultaram em deslocamento na direção apical, representando a extrusão do material de obturação no canal radicular.

The effects of post space preparation on the apical sealing ability of iRoot SP used for straight root canals / 实用口腔医学杂志

Objective: To evaluate the effects on the apical sealing ability of iRoot SP used for straight root canals. Methods: 73 extracted human teeth with straight roots were randomly assigned to 8 groups. The root canals in groups A3 was obturated with single gutta-percha cone. The others were obturated with thermoplasticized gutta-percha cones. The canals were filled with AH Plus (group A1 and B1), iRoot SP (group A2, A3 and B2) and ZOE (group A4) . The post space was prepared either immediately after obturation (A1-A4) or 7 days later group (B1 and B2) . The extent of dye penetration was measured by transparent dental technology. Results:There were no significant differences among A1-A3 groups, between group A1 and B1, A2 and B2, P＞ 0. 05. The dye penetration extent of group A4 and C was greater than that of group A2 (P ＜ 0. 05) . Conclusion: iRoot SP and AH Plus have same performance on root canal seal. There was no significant difference between iRoot SP + thermoplasticized gutta-percha and iRoot SP + single gutta-percha cone for apical sealing.

Influence of irrigants in association with ultrasound for cleaning root dentin surface after post space preparation: EDS analysis / Influencia de irrigantes en asociación con ultrasonido para la limpieza de la superficie de la dentina radicular después de la preparación del espacio para postes: análisis de espectroscopia de energía dispersiva

This study evaluated the cleanliness of post space after different irrigation protocols, associated or not to the use of ultrasound. Thirty-six single-rooted bovine roots were instrumented with rotary system, irrigated with 1 % hypochlorite and filled with Ah Plus sealer and gutta-percha cones. After seven days in stove at 37 °C, two-thirds of canal filling was removed by drilling and the post space preparation was irrigated with 2.5 % NaOCl (group NaOCl); 0.2 % chlorhexidine (group CLX); distilled water (group Water); 2.5 % NaOCl + ultrasound (group NaOCl-US); 0.2 % chlorhexidine + US (Group CLX-US); or water + US (Group Water-US). Roots were cleaved in mesiodistal direction, prepared for scanning electron microscope (SEM) to evaluate the smear layer and debris presence and for energy dispersive spectroscopy (EDS) analyses, to evaluate chemical components of dentin after treatment. The data were subjected to statistical analysis (two-way Anova and Tukey's test 5 %). EDS analysis showed the presence of chemical components of filling material in the samples from all groups. SEM images showed large amount of obliterated dentinal tubules. The use of ultrasound influenced the removal of some components of filling material (p<0.05), but not allowed for total cleaning. It was concluded that none of the irrigating solutions, associated or not to the use of ultrasound were able to completely clean the post space.

Este estudio evaluó la limpieza de la preparación para el espacio de los postes después de diferentes protocolos de irrigación, asociados o no al uso de ultrasonido. Treinta y seis raíces unirradiculares de bovinos fueron instrumentados con sistema rotatorio, irrigadas con un 1 % de hipoclorito y rellenadas con el sellador Ah Plus y conos de gutapercha. Después de siete días en horno a 37 °C, dos tercios de la obturación del canal se removió por perforación y la preparación del espacio para los postes fueron irrigadas con 2,5 % de NaOCl (grupo NaOCl); Clorhexidina 0,2 % (grupo CLX); agua destilada (grupo agua); 2,5 % NaOCl + ultrasonido (grupo NaOCl - US); 0,2 % de clorhexidina + US (Grupo CLX - US); y agua + US (grupo Agua - US). Las raíces se cortaron en dirección mesiodistal y se prepararon para el microscopio electrónico de barrido (MEB) con el fin de evaluar el barrillo dentinario y la presencia de restos; así como mediante el análisis de espectroscopía de energía dispersiva (EDS) para evaluar componentes químicos de la dentina después del tratamiento. Los datos fueron sometidos a análisis estadístico (pruebas ANOVA de dos factores y de Tukey al 5 %). El análisis EDS mostró la presencia de componentes químicos del material de relleno en las muestras de todos los grupos. Imágenes del MEB mostraron gran cantidad de túbulos dentinarios obliterados. El uso de la ultrasonido influyó en la eliminación de algunos de los componentes de material de relleno (p <0,05), pero no permitió la limpieza total. Se concluyó que ninguna de las soluciones de irrigación, asociadas o no a la utilización de los ultrasonidos fueron capaces de limpiar completamente el espacio para los postes.

Effect of immediate and delayed post space preparation on the apical seal of root canals obturated with different sealers and techniques

During mechanical preparation of the post space, the root canal filling may be twisted or vibrated, depending on several factors associated with the preparation technique and quality of filling. OBJECTIVE: The purpose of this study was to investigate the effect of immediate and delayed post space preparation on the integrity of the apical seal. MATERIAL AND METHODS: Sixty-four extracted human incisors were biomechanically prepared using the step-back technique. Sixty roots were randomly assigned to 6 experimental groups of 10 teeth each and the remaining 4 roots served as positive and negative controls (n=2). The root canals in the different groups were obturated with cold lateral and warm vertical condensation of gutta-percha and one of two sealers (Sealapex and Diaket). Post space was prepared either individually or simultaneously. An insulated copper wire was cut into 10-cm-long pieces. In each canal, one piece was inserted to maintain contact with gutta-percha and extended to the outside as one of two working electrodes. A stainless steel wire with the same dimensions of those of the copper wire, used as the other working electrode, was immersed into the background electrolyte from the center of the bottle. The electrical current between standard and experimental electrodes in canals was measured over a period of 10 days applying a conductivity meter. The Kruskal-Wallis test (p=0.05) determined whether there was a significant difference in microleakage among the groups and the Mann-Whitney U test (p=0.01) was used for multiple comparison grouping variables. RESULTS: The results suggest that only the differences between the root canal filling techniques were statistically significant (p<0.01). There were no statistically significant difference in the sealers and the times of filling removal for post space preparation (p>0.01). CONCLUSION: The quality of the root canal filling is important for the integrity of the apical seal.

Periapical tissue healing after post space preparation with or without use of a protection plug and root canal exposure to the oral environment: study in dogs

The purpose of this study was to evaluate the influence of coronal leakage on the healing of dogs' periapical tissues after root canal filling, post space preparation and protection or not with a temporary sealer plug. Forty root canals of dogs' teeth were instrumented and filled by the lateral condensation technique with gutta-percha points and Endomethasone or CRCS sealers. After post space preparation, the remaining filling material was protected or not with a plug of temporary Coltosol sealer and exposed to the oral environment for 90 days. Thereafter, the animals were sacrificed and the specimens were removed and prepared for histomorphological and histobacteriological analysis. The findings revealed 35 percent of microbial leakage in the groups without plugs and 15 percent of leakage in the groups with plugs. Statistical analysis showed that the use of a Coltosol plug improved significantly the histomorphological results regardless of the type of root canal sealer (p=0.05) and that CRCS and Endomethasone sealers showed similar results (p>0.05).

O propósito deste trabalho foi avaliar a influência da infiltração coronária no reparo dos tecidos periapicais após obturação dos canais radiculares, preparo para pino e proteção ou não de um "plug" de cimento temporário. Quarenta canais de dentes de cães foram instrumentados e obturados pela técnica da condensação lateral ativa com cones de guta-percha e os cimentos Endomethasone e CRCS. Após preparo para pino os remanescentes do material obturador foram protegidos ou não com um "plug" do cimento temporário Coltosol e expostos ao meio oral por 90 dias. Decorrido este período, os animais foram mortos e os espécimes foram removidos e preparados para análises histomorfológica e histobacteriológica. Foi observado 35 por cento de casos de infiltração bacteriana nos grupos sem "plug" e 15 por cento nos grupos com "plug". Concluiu-se estatisticamente que o "plug" de Coltosol foi eficiente no controle da infiltração coronária de microorganismos (p=0,05), e que os cimentos CRCS e Endomethasone apresentaram resultados semelhantes (p>0,05).