Comparison of Fracture Resistance between Different Treatment Modalities of Mutilated Endodontically Treated Teeth Using Polyether Ether Ketone.

AIM: To compare fracture resistance of multiple treatment modalities intended for mutilated teeth using polyether ether ketone (PEEK) and zirconia materials. MATERIALS AND METHODS: The study was divided into four groups according to treatment modality adopted (n = 14): fiber post (F), Nayyar core (N), endocrown (E), and Richmond crown (R). Each group was further subdivided into two groups (n = 7) according to the type of material used: zirconia (Z) and PEEK (P). Using computer-aided design/computer-aided manufacturing, restorations were constructed from both materials following tested treatment options and manufacturer direction. Finished restorations were then tried, seated, and cemented to their corresponding acrylic teeth. All specimens were tested for fracture resistance in universal testing machine with cross head speed of 0.5 mm/min speed until failure, which was confirmed by a sudden drop in the measurements of the testing machine. Results were recorded, tabulated, and statistically analyzed. Shapiro-Wilk normality tests were considered to evaluate the normality of the data distributions. One-way analysis of variance (ANOVA) followed by Tukey's post hoc analysis was conducted to analyze the fracture resistance significant differences. RESULTS: Descriptive statistics of the restoration material revealed statistically a higher mean value for PEEK material (3609 ± 188.1) than zirconia (2404 ± 425.6). One-way ANOVA revealed statistically significant differences between zirconia group (p < 0.0001). Regarding zirconia group statistical significance was detected between fiber post vs endocrown (p = 0.0299), fiber post vs Richmond crown (p < 0.0001), and Nayyar core vs Richmond crown (p = 0.0004). However, there was no statistically significant difference between PEEK group (P = 0.1614). CONCLUSION: Polyether ether ketone could present a reliable treatment option in endodontically treated teeth. CLINICAL SIGNIFICANCE: Using one-piece Richmond crowns constructed of PEEK could present a viable treatment option against conventional treatment options of root canal treatment (RCT) single-rooted teeth.

Influencia de la Morfología Externa de la Raíz de Primeros Premolares Superiores en la Sobreestimación del Espesor Radiográfico Radicular Durante la Preparación para Poste, Evaluados Mediante Tomografía Computarizada Cone Beam / Influence of the External Morphology of the Root of Upper First Premolars on the Overestimation of Radiographic Root Thickness During Post Preparation, Evaluated by Cone Beam Computed Tomography

La investigación tuvo como objetivo determinar la influencia de la morfología externa de la raíz de primeros premolares superiores en la existencia de sobreestimación radiográfica durante la preparación para poste. Con este fin se realizó un estudio transversal in vitro, donde 60 premolares superiores uniradiculares fueron instrumentadas con fresas Gates Glidden y Pesso de calibre 1, 2 y 3. Seguidamente se obtuvieron imágenes radiográficas digitales de cada pieza dentaria mediante un aparato posicionador a una distancia constante en sentido vestíbulo lingual, asimismo se realizaron imágenes tomográficas volumétricas de las muestras. En ambas técnicas imagenológicas se midió el espesor a mesial y distal de las piezas. La sobreestimación fue calculada mediante la diferencia de la medida tomográfica menos la radiográfica. Los resultados indicaron que en ambas paredes radiculares hubo diferencia significativa entre las medidas radiográficas y tomográficas (p<0,05), encontrándose en la pared distal diferencias altamente significativas (p<0,001); además se evidenció que la sobreestimación radiográfica fue mayor en la pared distal. El estudio concluyó que existe sobreestimación radiográfica en premolares superiores durante la preparación para poste de un 20,42 % en promedio, siendo la pared distal la estructura que presenta mayor sobreestimación.

SUMMARY: he investigation´s objective was to determine the influence of external morphology of the root of upper first premolars in the existence of radiographic overestimation during preparation for post. An in vitro cross-sectional study was carried out, where 60 single-rooted upper premolars were instrumented with burs. Gates Glidden and Pesso of caliber 1, 2 and 3, then, digital radiographic images of each dental piece were obtained by means of a positioning device at a constant distance in the buccolingual direction; volumetric tomographic images of the samples were also performed. In both imaging techniques, the mesial and distal thickness of the pieces was measured. The overestimation was calculated by the difference of the tomographic measurement minus the radiographic one. The results indicated that in both root walls there was a significant difference between the radiographic and tomographic measurements (p<0.05), with highly significant differences being found in the distal wall (p<0.001); In addition, it was evidenced that the radiographic overestimation was greater in the distal wall. The study concluded that there is radiographic overestimation in upper premolars during post preparation of 20.42% on average, with the distal wall being the structure that presents the greatest overestimation.

The effect of ultrasonic vibration protocols for cast post removal on the incidence of root dentin defects.

PURPOSE: To investigate the effects of two ultrasonic vibration protocols for cast post removal (single or double ultrasound units) on the development of defects in root dentin. METHODS: Sixty bovine incisors were selected. Fifteen roots were left unprepared (control). Forty-five roots were instrumented and filled. A 10-mm post space was prepared using #1-4 Largo drills. Fifteen teeth were prepared for post space and received no further procedure. Thirty roots had cast posts cemented and were submitted to ultrasonic vibration protocols for removal. The time necessary to remove each post was recorded. Roots were sectioned 3, 6, 9, and 12 mm from the coronal portion and viewed through a 25× magnification in a stereomicroscope. The presence of root fractures, partial cracks, and craze lines was registered. Chi-square and Fisher's exact tests were performed to compare the incidence of dentin defects. The Kruskal-Wallis test was performed to explore the difference between the time needed for post removal. The significance level was set at P = 0.05. RESULTS: Root defects were observed in all experimental groups. There were no statistical differences comparing previous root canal treatment and post removal steps, either with 1 or 2 ultrasonic units, in the formation of defects (P = 0.544) or fractures (P = 0.679). CONCLUSION: Ultrasonic vibration protocols for removing cast posts did not increase the number of dentin defects compared to root canal preparation and obturation and post space preparation steps.

Effect of the timing of radiation therapy on the push-out strength of resin cement to root dentine.

This study investigated the effect of radiation timing on the bond strength of resin cement to intraradicular dentine. Fifty human teeth were distributed into 5 groups (n = 10): Control (nonirradiated teeth), Before-RCT (teeth irradiated before root canal treatment), After-CH (teeth irradiated after canal preparation and placement of calcium hydroxide intracanal dressing), After-RCT (teeth irradiated after completion of root canal treatment) and After-FPL (teeth irradiated after luting of a glass fibre post). Each tooth received 70 Gy irradiation. The roots were sectioned for push-out strength testing. After-RCT and After-FPL groups had significantly lower push-out strength than the control at the middle third (p < 0.05). Control and After-CH groups had a higher percentage of cohesive dentine failure. Radiotherapy after root canal obturation and post luting adversely affected the adhesiveness of resin cement to intraradicular dentine. Teeth irradiated before root canal treatment and after placement of calcium hydroxide had the best performance.

The impact of provisional intraradicular retainers cementation with temporary methacrylate-based resin in the bond strength of glass fiber posts to root dentin.

Chemical composition of temporary cements interferes in the bond strength and quality of the bond interface of glass fiber posts to root dentin. The aim of the present study was to evaluate the influence of different temporary cements on the bond strength of fiberglass posts and resin cement. Thirty-two maxillary central incisor roots were standardized at 15 mm length. The root canals were prepared with Reciproc R50 and filled with a R50 single cone and AH Plus. Ten mm of filling material was removed with a heated Schilder condenser, leaving 5 mm of apical filling material. The roots were randomly distributed into 4 groups (n = 8). In the control group, the root canal was prepared with a standard drill according to the post diameter (DC #1, FGM, Joinville, Brazil), irrigated with 5 mL of distilled water and immediately received the fiberglass post cemented with self-adhesive resin cement. For the other groups, cores were made with temporary intraradicular retainers cemented with different temporary cements: methacrylate-based resin (Bifix Temp - Voco), calcium hydroxide-based (Provicol - Voco) and zinc oxide-based - eugenol-free (Relyx Temp NE - 3M). After 7 days, mechanical removal of the temporary retainers, preparation, irrigation of the root canal and cementation of the fiberglass post were performed, following the same protocol that had been performed in the control group. The roots were sectioned to obtain 3 slices per root third. The most cervical section of each third was used for the push-out test and failure pattern analysis, while the most apical section was subjected to analysis of the adhesive interface by scanning electron microscopy (SEM). The BS data were compared between groups using the two-way ANOVA and Tukey post-test. The failure pattern results were expressed in percentage and compared between groups using the chi-square test and the material adaptation data at the bond interface were evaluated using the Kruskal-Wallis and Dwass-Steel-Critchlow-Fligner tests. The results showed higher BS in the cervical third, with a higher value in the control group (10.8 ± 0.94) and Bifix Temp group (9.78 ± 0.71), with no statistically significant difference between these groups (P > .05). The middle and apical thirds showed no statistically significant difference (P > .05). As regards the type of failure, a higher percentage of mixed adhesive failures was observed for all groups. Analysis of the adhesive interface by SEM showed that the temporary cement Bifix Temp showed greater adaptation at the bond interface. It was concluded that the methacrylate-based resin temporary cement showed the highest bond strength values and best adaptation to root dentin than the zinc oxide-based and calcium hydroxide-based temporary cements.

Push-out bond strength of fiber posts to irradiated and non-irradiated intraradicular dentin.

OBJECTIVES: The aim of this study is to evaluate the influence of ionizing radiotherapy on the resin-dentin interface in endodontically treated teeth restored with fiber posts using a dual-cure resin cement performed with the etch-and-rinse (ER) and self-etch (SE) approaches in terms of push-out bond strength (MPa), and to analyze the post/cement/dentin interface using scanning electron microscopy (SEM). MATERIALS AND METHODS: Seventy-six single-rooted human teeth were used and randomly assigned into two main groups (n = 38): one non-irradiated group (NoRad) and one group subjected to a cumulative radiation dose of 60 Gy (Rad). All root canals were instrumented and were further subdivided into two subgroups (n = 19) following the adhesive approach: ER (RadER; NoRadER) and SE (RadSE; NoRadSE) used for fiber post luting with the universal adhesive and dual cure resin cement. Each root was sectioned perpendicularly to its long axis and sections from the middle third of the roots were chosen for SEM analysis and push-out bond strength test. Two-way ANOVA with post hoc Tukey tests and a dummy variable linear regression analysis were used for data analysis. RESULTS: Regardless of the adhesive approach, push-out bond strength in irradiated teeth resulted in significantly lower values than non-irradiated teeth (p = 0.0001). There were no significant differences between the ER and SE approaches in non-irradiated teeth (p = 0.955), whereas the ER approach showed significantly higher bond strengths than the SE approach in irradiated teeth (p = 0.0001). CONCLUSIONS: Ionizing radiotherapy resulted in dentin structure disruption and negatively affected the push-out bond strength of fiber posts to intraradicular dentin. The reduction in bond strength was also more significant with the SE approach than with the ER approach. CLINICAL RELEVANCE: The alterations resulting from root dentin irradiation seem to influence adhesive systems bond strength to dentin, as these changes contribute to lower push-out bond strength in irradiated groups before fiber post luting. Thus, clinicians should prepare patients with a reasonable restorative treatment plan prior to radiotherapy and simultaneously initiate a preventive program during radiotherapy.

Anatomical post: a simple and safe alternative

Objective: To describe a clinical case that called for an anatomical post to be made to support and retain an indirect restoration in the anterior tooth. Case report: A 72-year-old female patient came to the office complaining that the crown of tooth 22 had come loose. A clinical and radiographic examination of element 22 was performed, and showed a very broad root canal, total displacement of the cast metal crown-core set, and satisfactory endodontic treatment. The restorative planning for this patient included the making of an anatomical post from Exacto # 2 fiberglass post (Angelus, Brazil), and refilling it with Bulk One composite resin (3M, USA), using self-adhesive resin cement U200 (3M, USA). The reconstruction of the coronary portion of the post was also performed with the same composite resin (Bulk One 3M, USA). The preparation for full crown and temporary restoration was performed in the same session, using self-curing acrylic resin. The all-ceramic crown was molded and cemented in subsequent sessions. Conclusion: The use of anatomical posts with composite resin represents a technically viable alternative for rehabilitating endodontically treated teeth with wide root canals, in cases where conventional prefabricated fiber posts cannot be adapted easily. The advantages that stand out are that these posts can be applied easily, at low cost, and in a single session.

Objetivo: Descrever um caso clínico de confecção do pino anatômico para suporte e retenção de restauração indireta em dente anterior. Relato do Caso: Paciente feminina, 72 anos, compareceu ao consultório queixando-se que a coroa do dente 22 havia "soltado". Realizou-se exame clínico e radiográfico do elemento 22, que apresentou conduto radicular bastante amplo, deslocamento total do conjunto núcleo/coroa e tratamento endodôntico satisfatório. O planejamento restaurador para essa paciente incluiu a confecção de pino anatômico, com pino de fibra de vidro Exato #2(Angelus, Brasil) reembasado com resina composta Bulk One (3M, EUA), utilizando o cimento resinoso autoadesivo U200 (3M, EUA). Foi realizada a reconstrução da porção coronária do pino também com resina composta do tipo Bulk. Realizou-se, na mesma sessão de atendimento, o preparo para coroa total e restauração provisória utilizando dente de estoque e resinaacrílica autopolimerizável. Em sessões seguintes foi realizada a moldagem e cimentação da coroa total em cerâmica pura. Conclusão: A utilização de pinos anatômicos com resina composta representa uma alternativa tecnicamente viável, de fácil aplicabilidade, com baixo custo e em única sessão, para reabilitação de dentes tratados endodonticamente com conduto radicular onde os pinos em fibra pré-fabricados convencionais não apresentam boa adaptação.

Effects of irradiation, restoration and crown fracture type on the maximum load to fracture traumatized incisors: An ex vivo study.

BACKGROUND/AIMS: Radiotherapy makes teeth prone to tooth fractures. However, the relationship between radiotherapy and maximum load to fracture teeth that suffered a crown fracture is not fully understood. The aim of this study was to evaluate the influence of fracture type, radiation dose, fracture time, and their interactions on maximum load to fracture irradiated teeth. MATERIAL AND METHODS: A total of 140 permanent incisors were divided into two fracture type groups (uncomplicated and complicated) each of which included seven radiation dose subgroups (0, 10, 20, 30, 40, 50, and 60). The test groups were exposed to high-energy X-ray at 2 Gy/day, 5 days/week for a total dose of 10-60 Gy. Control groups were not irradiated. The load where the specimen started to break was obtained two different times. The 1st fracture was performed after radiation therapy, and the 2nd fracture was performed after the restoration of these samples. RESULTS: Fracture type had no effect on the maximum load to fracture. In contrast, the maximum load to fracture teeth decreased with increasing radiation doses. Maximum load to fracture the restored teeth was lower than the 1st fracture results. The general linear model procedure revealed a significant interaction between radiation dose and fracture time. Similarly, there was a significant interaction between the fracture type, radiotherapy dose, and fracture time. Maximum load values of teeth with complicated crown fractures restored with fiber posts and composite were not affected by radiation. CONCLUSION: Teeth that have been subjected to radiotherapy have an increased risk of fracture during dental trauma. However, restoration of the irradiated teeth with fiber posts and composite resin did not affect the maximum load required to fracture them.

Assessment of push-out bond strength of post-surface pretreatment before salinization using hydrogen peroxide, aluminum trioxide, and natural photosensitizers to radicular dentin.

OBJECTIVE: The study aimed to evaluate the effect of different post surface pretreatment methods i.e., 24% hydrogen peroxide (H2O2), riboflavin photosensitizer (RFP), curcumin photosensitizer (CP) and aluminum oxide (Al2O3), and silane only on the bond values of glass fiber post to resin cement MATERIALS AND METHODS: Fifty single-rooted human teeth were obtained and crowns were sectioned coronally to the cementoenamel junction (CEJ). Protaper universal file system was used for canal cleaning and shaping followed by obturation. Post space was prepared and all the posts were then randomly divided into five groups depending on the surface pretreatment used (n = 10). Group 1: 24% H2O2 + silane, Group 2: RFP + silane, Group 3: CP + silane, Group 4: Al2O3 + silane, Group 5: silane only. Post-surface treatment was followed by post-placement using a self-etch dual-cure cement Panavia F 2.0. Acrylic blocks were used to hold the specimens perpendicularly and all the samples were sectioned by slow-speed saw into coronal, middle, and apical third. The universal testing machine determines pushout bond strength and failure mode was analyzed by stereomicroscope. One-way analysis of variance (ANOVA) and Tukey multiple comparison tests were used to analyze data. RESULT: The coronal section of group 4 (Al2O3 + silane) displayed the highest PBS (8.23±0.14 MPa). Whereas, an apical third of group 2 (RFP + silane) exhibited the lowest PBS (2.02±0.12 MPa). PBS values in samples in group 1 surface treated with 24% H2O2 + silane displayed comparable outcomes to samples in group 4 at all three levels (p>0.05). Samples in group 2 (RFP + silane) group 3 (CP + silane) and group 5 (Silane Only) demonstrated comparable PBS (p>0.05). CONCLUSION: Glass fiber reinforced post-surface pretreatment method using hydrogen peroxide and aluminum trioxide along with silane improves push-out bond strength at all three levels (coronal, middle, and apical). The use of a silane coupling agent on glass fiber posts alone does not improve bond values. The practice of photosensitizer on post-surface needs to be investigated further.

Retratamiento y reparación de una perforación radicular. Informe clínico, radiográfico e histológico / Retreatment and healing of a case of root perforation. Clinical, radiographic and histological report

Objetivo: Describir los aspectos clínicos, radiográfi- cos e histológicos del retratamiento realizado en un segundo molar superior en el que se había producido previamente una perforación radicular durante el tratamiento original. Caso clínico: Un paciente masculino de 50 años con- currió a la consulta para realizar un retratamiento endodóntico en un segundo molar superior derecho. El examen radiográfi- co reveló la presencia de un tratamiento incompleto, un área radiolúcida periapical y una perforación radicular producida por un poste roscado insertado fuera del espacio del conducto mesio vestibular. Una vez retirado el poste, se selló la perfo- ración con Biodentine y se realizó el retratamiento. Luego de dos años, el paciente regresó a la consulta con dolor a la mas- ticación, localizado en el área correspondiente al segundo mo- lar superior derecho previamente tratado. Durante el examen clínico y radiográfico se detectó la presencia de una fractura vertical en la raíz palatina. A causa del severo compromiso radicular el molar fue extraído y derivado para su análisis his- tológico. El informe del laboratorio reveló que la perforación había sido reparada por medio de la aposición de un nuevo tejido calcificado y que el remanente periodontal adherido a la raíz se encontraba dentro de los límites normales. El presente caso clínico resalta la importancia que tiene el conocimiento cabal de la anatomía del sistema de conductos radiculares con el objeto de evitar errores de procedimiento que puedan influir negativamente en el pronóstico del tratamiento (AU)

Aim: To describe the clinical, radiographic and histo- logical aspects of the retreatment of a second upper molar in which root perforation had occurred during the original treatment. Clinical case: A 50-year old male was referred for endo- dontic retreatment of the right second maxillary molar. Radi- ographic examination revealed the presence of an incomplete root canal treatment, a radiolucent periapical area and a root perforation produced by a threaded post placed outside of the mesiobuccal root canal. After post removal, the root perfo- ration was sealed with Biodentine and the root canals were retreated. Two years later, the patient returned to the office com- plaining of severe pain during mastication, in the area of the previously retreated right second maxillary molar. Clinical and radiographic examination revealed the presence of a ver- tical fracture on the palatal root. Since this kind of root dam- age non-restorable, the tooth was extracted and submitted to histologic analysis. The laboratory report revealed that the perforation site had healed by the apposition of new calci- fied tissue, and that the remnants of periodontal tissue which persisted attached to the root were within normal limits. This clinical case highlights the importance of thorough knowl- edge of the anatomy of the root canal system in order to avoid procedural errors which may compromise the prognosis of the treatment (AU)

Chemical analysis of irradiated root dentin and its interaction with resin cements.

OBJECTIVES: To investigate the chemical changes in root dentin submitted to ionizing radiation and how it affects the interaction with resin cements. MATERIALS AND METHODS: Forty human premolars were randomly divided into two groups (n = 20): non-irradiated and irradiated. They were randomly subdivided according to the type of resin cement (n = 10): conventional (RelyX ARC, 3 M ESPE) or self-adhesive (RelyX U200, 3 M ESPE). After cementation of the fiberglass posts, the roots were sectioned to be analyzed by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and confocal laser scanning microscopy (CLSM). The data obtained from FTIR and Raman were analyzed using two-way ANOVA followed Tukey's test (α = 0.05). For CLSM, a descriptive analysis was performed. RESULTS: In the FTIR, there was a significant difference between the non-irradiated and irradiated groups for phosphate (p = 0.011), carbonate (p < 0.001), amide III (p = 0.038), and carbonate/mineral ratio (p < 0.001). Regarding the root third, there was a difference for amide I (p = 0.002), mineral/matrix ratio (p = 0.001), and amide I/CH2 (p = 0.026) between the cervical and the others. Raman spectroscopy revealed no difference between groups for 961/1458 cm-1 in the diffusion zone. CLSM showed a different interaction pattern for the two cements with the irradiated dentin from the cervical third. CONCLUSIONS: Ionizing radiation altered the chemical composition of root dentin, especially in the cervical third. The resin cements showed less interaction with the irradiated root dentin. CLINICAL RELEVANCE: As radiotherapy alters the chemical composition of root dentin, the interaction of resin cement with dentin can compromise the success of rehabilitation with fiberglass posts.

Novo sistema de retentor pré-fabricado perfurado e de iluminador em fibra óptica: estudo da resistência mecânica frente a variação dos cimentos resinosos / New system of hollow prefabricated post and optical fiber illuminator: study of the mechanical strength by varying resin cements

O presente estudo teve por objetivo avaliar a resistência à flexão de um pino experimental de fibra de vidro vazado, e a resistência adesiva entre este pino experimental à dentina radicular, associando a utilização de um dispositivo iluminador em fibra óptica, sob o processo de envelhecimento, além de determinar a distribuição de tensão pela Análise de Elementos Finitos (FEA). O pino experimental e o dispositivo iluminador de fibra óptica têm por finalidade aumentar a efetividade de fotoativação dos cimentos resinosos nos terços médios e apicais dos canais radiculares. Para o teste de flexão de 3 pontos, estritamente do pino de fibra de vidro, as amostras foram divididas em 4 grupos (n=10): pino convencional (pc), pino experimental sem preenchimento (pp), com preenchimento de cimento resinoso (ppc) e com preenchimento de fibra óptica (ppf). Para o teste de resistência adesiva Pull-out, 100 raízes de dentes bovinos foram restauradas com retentores intrarradiculares e coroas de resina composta, distribuídos em 10 grupos (n=10), tendo como variáveis: o tipo de pino de fibra de vidro [convencional (C) ou perfurado (P)], o sistema de fotoativação [com ou sem o iluminador de fibra óptica (O)], o tipo de cimento resinoso [fotoativado (F) ou polimerização dual (D)] e o envelhecimento das amostras [com e sem ciclagem mecânica (C)]. O processo de envelhecimento foi realizado através da ciclagem mecânica e as amostras foram submetidas ao teste de resistência adesiva Pull-out. A análise do modo de falha foi realizada em Estereomicroscópio. A Análise em Elementos Finitos avaliou a distribuição de tensão pela análise de von Mises, deformação total e tensão máxima principal no Software Ansys 19.3. A análise estatística foi constituída pelo teste de normalidade Shapiro-Wilk, análise de variância (ANOVA) 1, 2 e 3 fatores e teste Tukey 5%. As médias e desvios padrão de resistência à flexão foram (MPa): pc = 677 ± 81,1; ppc = 419 ± 23,2; ppf = 200 ± 32,5 e pp = 177 ± 32,8. As médias e desvios padrão de resistência adesiva foram (MPa): CD = 12,2 ± 1,21; PD = 11,1 ± 1,32; PF = 10,9 ± 1,29; POD = 13,7 ± 1,16; POF = 11,9 ± 1,48; CDC = 10,1 ± 1,33; PDC = 9,25 ± 1,11; PFC = 8,37 ± 1,25; PODC = 10,8 ± 0,95 e POFC = 9,82 ± 1,02. Os resultados do modo de falha foram: adesiva entre pino e cimento (56%), mista predominantemente adesiva entre cimento e dentina (22%), adesiva entre cimento e dentina (14%) e a mista predominantemente adesiva entre pino e cimento (8%). Concluiu-se que entre os pinos experimentais, o grupo do pino perfurado preenchido com cimento resinoso obteve o maior valor de resistência à flexão, a utilização do dispositivo iluminador aumentou os resultados de resistência adesiva nos grupos dos pinos perfurados e não houve diferença na distribuição de tensões entre os grupos. (AU)

The present study aimed to evaluate the flexural strength of an experimental hollow glass fiber post, and the bond strength between this experimental post and root dentin, associating the use of an optical fiber illuminating device, under the aging process, in addition to determine the stress distribution by Finite Element Analysis (FEA). The experimental post and optical fiber illuminating device are intended to increase the polymerization effectiveness of resin cements in the middle and apical regions of root canals. For the 3-point bending test, strictly of the fiber post, the samples were divided into 4 groups (n=10): conventional post (pc), experimental post without filling (pp), with resin cement filling (ppc) and with optical fiber filling (ppf). For the Pull-out test, 100 roots of bovine teeth were restored with intraradicular retainers and composite resin crowns, distributed into 10 groups (n=10), with the following variables: glass fiber post type [conventional (C) or hollow (P)], the photocuring system [with or without the optical fiber illuminating device (O)], the type of resin cement [light cured (F) or dual cured (D)] and aging of the samples [with and without mechanical cycling (C)]. The aging process was performed by mechanical cycling and the samples were submitted to the Pull-out bond strength test. Failure mode analysis was performed using a stereomicroscope. Finite Element Analysis evaluated the stress distribution by von Mises analysis, total strain and maximum principal stress in Ansys Software 19.3. Statistical analysis consisted of the Shapiro-Wilk normality test, 1-, 2- and 3-way analysis of variance (ANOVA) and Tukey test 5%. The means and standard deviations of flexural strength were (MPa): pc = 677 ± 81.1; ppc = 419 ± 23.2; ppf = 200 ± 32.5 and pp = 177 ± 32.8. The means and standard deviations of bond strength were (MPa): CD = 12.2 ± 1.21; PD = 11.1 ± 1.32; PF = 10.9 ± 1.29; POD = 13.7 ± 1.16; POF = 11.9 ± 1.48; CDC = 10.1 ± 1.33; PDC = 9.25 ± 1.11; PFC = 8.37 ± 1.25; PODC = 10.8 ± 0.95 and POFC = 9.82 ± 1.02. The failure mode results were: adhesive between post and cement (56%), mixed predominantly adhesive between cement and dentin (22%), adhesive between cement and dentin (14%) and mixed predominantly adhesive between post and cement (8 %). It was concluded that among the experimental posts, the hollow post group filled with resin cement obtained the highest flexural strength value, the use of the illuminating device increased the results of bond strength in the hollow post groups and there was no difference in the stress distribution among the groups (AU)

Influência da férula na resistência à fratura de restaurações com utilização ou não de retentores intrarradiculares em dentes tratados endodonticamente: uma revisão da literatura / Influence of the ferrule on the fracture resistance of restorations with or without the use of intraradicular posts in endodontically treated teeth: a literature review

Objetivo: realizar uma revisão de literatura narrativa sobre a importância e a influência do efeito férula na resistência à fratura de restaurações em dentes tratados endodonticamente com utilização ou não de retentores intrarradiculares. Metodologia: Foram utilizados os seguintes descritores indexados no DeCS (Descritores em Ciências da Saúde): "Férula", Prótese Dentária", "Falha da Restauração Dentária", "Técnica de Retentor Intrarradicular" e "Pinos de Retenção Dentária" para busca nas bases de dados PubMed, Embase, Lilacs, Web of Science, Scopus e Cochrane Library. Resultados: Os dados da maioria dos estudos in vitro ou in vivo incluídos nesta revisão sugerem o uso da férula para aumento da resistência à fratura e longevidade dos dentes tratados endodonticamente. Tem sido recomendada a confecção de uma férula com altura uniforme de 2 mm e espessura superior a 1,5 mm. Conclusão: O uso de retentores radiculares foi indicado pela maioria dos trabalhos, sendo geralmente recomendados os pinos de fibra de vidro ao invés de núcleos metálicos fundidos para minimizar os riscos de fratura radicular em razão do módulo de elasticidade semelhante à dentina, além de possibilidade de retratamentos em casos de falhas adesivas. Apesar disso, ainda são necessários estudos clínicos com acompanhamento a longo prazo para avaliar a longevidade das restaurações de dentes tratados endodonticamente utilizando pinos de fibra de vidro sem ou com a presença de férula em diferentes espessuras e alturas.

Objective: This study aimed to conduct a narrative literature review on the importance and influence of the ferrule effect on the fracture resistance of restorations in endodon-tically treated teeth with or without the use of intraradicular posts. Methodology: The following descriptors indexed in the DeCS (Health Sciences Descriptors) were used: "Ferrule", Dental Prosthesis", "Dental Restoration Failure", "Post and Core Technique", and "Dental Posts", to search on the databases of PubMed, Embase, Lilacs, Web of Science, Scopus, and Cochrane Library data. Results: Data from most of the in vitro or in vivo studies included in this review suggest the use of the ferrule to increase fracture resistance and longevity of endodontically treated teeth. It has been recommended to make a ferrule with a uniform height of 2 mm and a thickness greater than 1.5 mm. Conclusion: The use of intraradicular posts was indicated by most studies, and fiberglass posts are generally recommended instead of cast metal cores to minimize the risk of root fracture due to the modulus of elasticity similar to dentin, in addition to the possibility of retreatments in ad-hesive failure cases. Despite this, clinical studies with a long-term follow-up are essential to evaluating the longevity of restorations of endodontically treated teeth using fiberglass posts without or with the presence of ferrule in different thicknesses and heights.

Influência de um novo dispositivo acessório de fotopolimerização com fibra óptica e pino de fibra de vidro experimental nas propriedades mecânicas, físicoquímicas e adesão dos cimentos resinosos / Influence of a new light curing device with optical fiber and an experimental glass fiber post on the physicochemical, mechanical properties and adhesion of resin cement

O objetivo deste estudo foi avaliar in vitro a influência de um novo dispositivo fotopolimerização e pino de fibra de vidro nas propriedades mecânicas, físicoquímicas e adesão dos cimentos resinosos. Foram utilizados oitenta dentes bovinos, submetidos ao tratamento endodôntico, distribuídos em 5 grupos (n=16): CD (Pino fibra vidro e cimento dual); PF (Pino perfurado e cimento fotoativado); PD (Pino perfurado e cimento dual); POF (Pino perfurado iluminador de fibra óptica e cimento fotoativado); POD (Pino perfurado iluminador de fibra óptica e cimento dual). Os dentes foram preparados para colocação de um protótipo de pino em fibra de vidro que possui um canal interno de diâmetro regular e com conicidade progressiva. A perfuração permite a inserção da fibra óptica ao longo da extensão do pino a fim de possibilitar a ação da luz ao longo de todo o comprimento do conduto radicular. Após a cimentação, os espécimes foram seccionados perpendicularmente, e obtida 1 fatia de 2 mm de espessura do terço apical, médio e cervical. A avaliação mecânica foi realizada através do ensaio de push-out para determinação da resistência adesiva nos terços cervical, médio e apical seguido pela análise da fratura em estereomicroscópio. Os retentores intrarradiculares foram também submetidos ao teste de flexão de 3 pontos para análise do material preenchedor do pino de fibra (n=10). As análises físico - químicas foram realizadas através da determinação do grau de conversão dos cimentos (RAMAN) e análise em espectroscopia de energia dispersiva (EDS) dos monômeros presentes. A adesão foi analisada pela interface de cimentação pelo MEV e reconstrução 3D do novo sistema através do Micro-CT. Os dados obtidos foram analisados estatisticamente pelo ANOVA (um e dois fatores) e comparação múltipla de Tukey, (p<0,05). Os resultados de resistência adesiva evidenciaram que o terço apical obteve o maior valor de resistência adesiva em comparação ao terço médio (p<0,001), o grupo POD do terço apical foi estatisticamente significante em relação ao grupo CD do terço médio (p<0,001). Na analise individual de cada terço, não houve diferença entre os grupos experimentais e o controle (p>0,05). A falha adesiva entre cimento e dentina foi a mais predominante entre todos os grupos e terços. O pino de fibra de vidro (controle) obteve o maior valor de resistência à flexão (p<0,001), seguido do pino de fibra de vidro perfurado preenchido com cimento resinoso (p<0,001). Os maiores valores de GC foram alcançados pelo grupo POD com 82,3% (cervical) 69,9 % (médio) e 76,21% (apical) e o EDS comprovou a presença de componentes químicos adequados. A análise da adesão do novo pino de fibra de vidro comprova uma excelente adaptação no interior do canal radicular nas regiões cervical, médio e apical. Portanto o novo dispositivo com fibra óptica e pino de fibra de vidro experimental aumentaram as propriedades mecânicas, físico-químicas e adesão do cimento resinoso (AU)

The aim of this study was to evaluate in vitro the influence of a new light curing device with optical fiber and experimental glass fiber post on the physicochemical, mechanical, and adhesion properties of resin cements. Eighty bovine teeth were used, submitted to an endodontic treatment, distributed in 5 groups (n=16): CD (Glass fiber post and dual cement); PF (Perforated post and light-cured cement); PD (Perforated post and dual cement); POF (Fiber optic illuminating with a perforated post and lightcured cement); POD (Fiber optic illuminating with a perforated post and dual cement). The teeth were prepared for placement of a glass fiber post prototype, which has an internal canal of regular diameter and progressive taper. The internal perforation extension allows the insertion of the optical fiber along the entire length of the post in order to allow the action of light along the entire length of the root canal.The specimens were sectioned perpendicularly for the tests, and 1 slice approximately 2 mm thick was obtained from the apical, middle and cervical thirds. The mechanical evaluation was carried out through the push-out test to determine the adhesive bond strength, in the cervical, middle and apical thirds, followed by the fracture analysis under a stereomicroscope, the intraradicular post were also submitted to the 3-point bending test for material analys of the fiber post filler (n=10). The physicochemical analyzes were performed by determining the degree of conversion of the cements (RAMAN) of each sample and the analysis of energy dispersive spectroscopy (EDS) of the monomers present. Adhesion was analyzed by the cementation interface and 3D reconstruction of the new system through micro-CT, and finally, SEM analysis of the adhesive interface. The data obtained were analyzed for normality and statistically by ANOVA (one and two ways) and Tukey's multiple comparison (p<0.05). The adhesive bond strength results showed that the apical third had the highest value of adhesive strength compared to the middle third (p<0.001), and the POD group of the apical third was statistically significant in relation to the CD group of the middle third (p<0.001). In the individual analysis of each third, there was no difference between the experimental and control groups (p>0.05). Adhesive failure between cement and dentin was the most prevalent among all groups and thirds. The conventional post (control) had the highest flexural strength value (p<0.001), followed by the perforated fiberglass post filled with resin cement (p<0.001). The POD group achieved the highest GC values with 82.3% (cervical), 69.9% (medium), and 76.21% (apical) and EDS confirmed the presence of adequate chemical components. The analysis of the adhesion of the new fiberglass post proves an excellent adaptation inside the root canal in the cervical, middle and apical regions. Therefore, the new light curing device with optical fiber and experimental glass fiber post improved the resin cement's mechanical, phycochemical, and adhesion. (AU)

¿Cómo mejorar la función eréctil post-prostatectomía radical? / How to improve erectile function after radical prostatectomy?

La prostatectomía radical (PR) es uno de los pilares en el manejo del cáncer próstata. Esta cirugía constituye un reto para el urólogo, quien debe encontrar un balance entre el riesgo de extensión extraprostática y el grado de preservación del tejido neural. A pesar del avance en técnicas quirúrgicas, la incontinencia urinaria y disfunción eréctil (DE) post-prostatectomía continúan impactando considerablemente la calidad de vida de los pacientes. Por lo anterior, un abordaje transdisciplinario desde el momento del diagnóstico es esencial para mejorar los desenlaces funcionales y oncológicos.

Radical prostatectomy (RP) is one of the mainstays in the management of prostate cancer. This surgery constitutes a challenge for the urologist, who must find a balance between the risk of extraprostatic extension and the degree of preservation of neural tissue. Despite advances in surgical techniques, post-prostatectomy urinary incontinence and erectile dysfunction (ED) continue to significantly impact the quality of life of patients. Therefore, a transdisciplinary approach from the time of diagnosis is essential to improve functional and oncologic outcomes.

Estudio microtomográfico de la porosidad en la cementación de postes de fibra / Microtomographic study of the porosity in the cementation of fiber posts

El objetivo de este estudio fue evaluar con microto-mografía los poros existentes entre el cemento de resina, poste de fibra y paredes del conducto en los distintos tercios radiculares en premolares inferio-res. Se utilizaron 15 premolares inferiores unirra-diculares humanos recientemente extraídos. Se les realizó el tratamiento endodóntico, y se obturó con conos de gutapercha y cemento endodóntico a base de resina. Una vez desobturados se procedió a la ce-mentación de los postes. Cada muestra se posicionó en un accesorio personalizado y se escaneó utilizan-do un Microtomógrafo. Con el software CTAn v.1.12 (Bruker-microCT) se analizaron las microtomografías para obtener el volumen de interés (VOI) que permi-tió calcular el área de superficie (mm2) y volumen de cada poro (mm3) entre la dentina y el poste a nivel co-ronal, medio y apical. Los datos fueron analizados me-diante las pruebas estadísticas de Friedman o ANOVA de medidas repetidas. El volumen de los poros entre los tres tercios radiculares mediante la prueba de Friedman, encontró una diferencia global significativa (F = 30,00; p < 0,05). El tercio en donde los poros presentaron un mayor volumen (mm3) fue el tercio coronal (mediana: 0,29250), seguido por los tercios medio (mediana: 0,03200), y apical (mediana: 0,00140). La comparación de la superficie de los poros entre los 3 tercios brindó un resultado análogo al de la comparación del volumen. La mayor superficie (mm2) correspondió al tercio coronal (media ± DE = 1,66377 ± 0,27175), seguido por los tercios medio (media ± DE = 1,16210 ± 0,20343) y apical (media ± DE = 0,41074 ± 0,12641). La microtomografía permitió realizar un análisis cuantitativo y cualitativo de los poros en toda la muestra, sin deterioro de la misma. Se puede concluir que el tercio coronal presenta más poros que el tercio apical con la técnica de cementación utilizada. En cuanto a la superficie y volumen de los poros, los resultados encontrados son similares a los reporta-dos por diversos autores (AU)

The aim of this study was to evaluate with microtomography the existing pores between the resin cement, fiber post and canal walls in the different in thirds of the canal, in single-root lower premolars. Fifteen recently extracted human single root lower premolars were used, endodontically treated, and filled with gutta-percha cones and resin-based endodontic cement. Once unfilled, the posts were cemented. Each sample was positioned on a custom fixture and scanned using a Microtomograph. Each sample was evaluated using CTAn v.1.12 software (Bruker-microCT) to obtain the surface area (mm2), volume of interest (mm3) of each pore between dentin and post at the coronal, middle and apical levels. Data were analyzed using Friedman's tests or repeated measures ANOVA. The volume of the pores between the three root thirds using the Friedman test, a significant global difference was found (F = 30.00; p < 0.05). The third in which the pores presented a greater volume (mm3) was the coronal third (means: 0.29250), followed by the middle (means: 0.03200) and apical (means: 0.00140) thirds. The comparison of the pore surface between the 3 thirds gave an analogous result to that of the volume comparison. The largest surface area (mm2) corresponded to the coronal third (mean ± SD 1.66377 ± 0.27175), followed by the middle (mean ± 1.16210 ± 0.20343) and apical (mean ± 0.41074 ± 0.12641) thirds.Microtomography allowed a quantitative and qualitative analysis of the pores in the entire sample without deterioration. It can be concluded that the coronal third has more pores than the apical third with the cementation technique used. Regarding the surface and volume of the pores, the results found are similar to those reported by various authors (AU)

Influence of customization and light-curing device on the bond strength of glass fiber posts - in vitro study / Influência da reanatomização e do aparelho fotopolimerizador na resistência de união de pinos de fibra de vidro - estudo in vitro

Introduction: Endodontically treated teeth are usually affected by extensive structure loss requiring the use of intraradicular posts to provide retention and restoration. Objective: An in vitro assessment was performed on the bonding of glass fiber posts to the root dentin. Material and method: Ninety (n = 10) single bovine roots were used in a 3 x 3 x 3 factorial study with subdivided plots: post customization varying the presence and type of resin (without customization, conventional resin, and Bulk Fill resin), light-curing device (Valo, Radii-Cal, Rainbow), and root third (cervical, middle, and apical). Result: For the customization factor, Tukey's test (5%) showed the superiority of the Bulk Fill (8.16 MPa) and Z350 (7.40 MPa) groups compared to the control group (4.92 MPa), without differing from each other. All light-curing devices differed, showing the superiority of Valo (9.36 MPa), Radii (6.96 MPa) as an intermediate, and the inferiority of Rainbow (4.17 MPa). The cervical root third (7.81 MPa) was superior, the apical third was inferior (5.80 MPa), and the middle third (6.88 MPa) was an intermediate without differing from the others. Conclusion: The customization of glass fiber posts increases the bond strength to the root dentin, regardless of the resin used. There was a compromise in the apical third and when using light-curing devices with lower light intensity.

Introdução: Dentes com extensa perda de estrutura podem comprometer a retenção das restaurações ao remanescente dental, onde pinos intraradiculares são indicados. Objetivo: Avaliou-se in vitro a união de pinos de fibra de vidro à dentina radicular em função de diferentes modos de reanatomização, fotopolimerizadores e regionalização radicular. Material e método: Noventa (n=10) raízes bovinas uniradiculares foram usadas num estudo fatorial 3 x 3 x 3 com parcelas subdivididas: Reanatomização do pino, variando a presença e tipo de resina (Sem reanatomização, Resina Convencional e Resina Bulkfill); Fotopolimerizador (Valo, Radii-cal, Rainbow); e Terço radicular (cervical, médio e apical). Resultado: O teste de Tukey (5%) evidenciou para o Fator Reanatomização superioridade dos grupos BulkFill (8.16MPa) e Z350 (7.40MPa) ao grupo Controle (4.92MPa), sem diferirem entre si. Todos os fotopolimerizadores diferiram entre si, com superioridade de Valo (9.36MPa), Radii (6.96MPa) intermediário, e inferioridade de Raiwbow (4.17MPa). O terço radicular cervical (7.81MPa) foi superior e o apical inferior (5.80MPa), com o terço médio (6.88MPa) intermediário e sem diferir dos demais. Conclusão: Conclui-se que a reanatomização de pinos de fibra de vidro aumenta a resistência de união à dentina radicular, independentemente da resina utilizada, havendo prejuízo no terço apical e quando são empregados fotopolimerizadores com menor intensidade luminosa.

Cast metal posts versus glass fibre posts: which treatment of choice based on cost-minimisation analysis?

Aim The aim of this randomised clinical trial based on cost-minimisation analysis was to assess and compare four post-retained restorative strategies for endodontically treated teeth.Methods A total of 225 endodontically treated teeth in 141 patients were evaluated annually between 2009 and 2018. In this sense, the teeth were divided into four groups according to the treatment strategy, where three groups were treated with glass fibre posts in combination with composite resin restorations or single metal-ceramic crown with or without ferrules, and one group was treated with cast metal posts with metal-ceramic crowns. According to the outcome of the treatment during follow-up, the teeth received additional treatments, which ranged from restoration repair, re-cementation, endodontic retreatment, apical surgery, post/crown replacement to tooth extraction and replacement through metal-ceramic implant-supported crown. Thus, cost-minimisation analysis was based on November 2018 values from the Brazilian Public Health System, considering the primary costs related to the post, restoration or crown, and incremental costs related to the outcomes during follow-up.Results Primary treatment costs were lower for the group using glass fibre posts in combination with composite resin restorations (US$27.11), while the highest costs were for the group using cast metal post with metal-ceramic crown (US$153,14). In turn, the incremental costs due to tooth removal, implant placement and metal-ceramic crown (US$363.92) were the highest, while the lowest costs were related to procedures for crown re-cementation (US$6.11) followed by repair of the resin restoration (US$16.47). In this regard, the highest percentage of failures was related to restoration fractures in the glass fibre posts in combination with the composite resin restorations group. However, the average annual cost was significantly lower in the group that used glass fibre posts in combination with composite resin restorations (p <0.001) when compared to the other groups, with or without ferrules.Conclusions The treatment of endodontically treated teeth using glass fibre posts in combination with composite resin restorations presented a significantly lower average annual cost when compared to treatments that consider the use of cast metal posts, metal-ceramic crowns, with or without ferrules.

Techniques for removing root canal posts: an vitro study / Técnicas para remoção de pinos intrarradiculares: um estudo in vitro

Objetivo: O objetivo deste estudo foi responder qual é a melhor técnica para remoção de pinos de fibra de vidro e pinos metálicos fundidos considerando tempo, preservação da estrutura dentária e custos. Métodos: Foi realizado um estudo in vitro, randomizado e cego. Sessenta dentes tratados endodonticamente foram randomizados em dois grupos de acordo com o tipo de pino. Uma segunda randomização foi realizada para cada tipo de técnica de remoção (ultrassom, broca ou combinada; n=10). One-way ANOVA foi usado para comparar o tempo de remoção do pino, teste t pareado comparou a quantidade de estrutura dentária removida e Kruskal Wallis seguido pelo teste post hoc de Mann-Whitney foram usados para análise de custo (P = 0,05). Resultados: Não houve diferença no tempo de remoção do pino considerando o tipo ou técnica do pino (P=0,630). A perda média de estrutura dentária na região cervical foi superior a 30% quando apenas uma ponta diamantada foi usada para remover pino de fibra de vidro (P<0,00001) e pino metálico fundido (P=0,008). Conclusão: De acordo com os resultados deste estudo, podemos concluir que a seleção da técnica de remoção dependerá da habilidade do operador, e sempre ocorrerá alguma perda de estrutura dentária, embora seja esperada uma perda maior quando apenas pontas diamantadas são usadas para este fim.(AU)

Objective: The aim of this study was to answer which is the best technique to removing glass fiber post and cast metal post considering time, preservation of tooth structure, and costs. Methods: An in vitro, randomized, blinded study was conducted. Sixty endodontically treated teeth were randomized into two groups according to post type. A second randomization was performed for each type of removal technique (ultrasound, drill, or combined; n=10). One-way ANOVA was used to compare the time to post removal, paired t-test compared the amount of tooth structure removed and Kruskal Wallis followed by post hoc Mann-Whitney test were used for cost analysis (P=0.05). Results: There was no difference in post removal time considering post type or technique (P=0.630). The average loss of tooth structure in the cervical region was greater than 30% when only a diamond bur was used to remove fiber glass post (P<0.00001) and cast metal post (P=0.008). Conclusion: According to the results of this study, we can conclude that the selection of the removal technique will depend on the skill of the operator, and some loss of tooth structure will always occur, although greater loss is expected when only diamond burs are used for this purpose.(AU)

Single-Tooth Rehabilitation Combining Root Displacement and Crown Lengthening Two-Year Follow-Up: A Case Report.

Rehabilitation of an extensively compromised single anterior tooth represents an intriguing challenge for dentists, particularly when the rehabilitation involves esthetic, psychosocial, and functional requirements. The success in rehabilitating a patient with a conservative approach depends on a critical evaluation of the remaining structures, precise treatment plan, systematic treatment strategies, and patient compliance. In this case, the patient's chief complaint was the undesirable appearance of the maxillary right lateral, caused by the displacement of the post and crown. Clinical examination revealed a remaining tooth with coronal fracture, severe loss of tissue due to caries, and absence of ferrule effect. Radiographic examination revealed that the fracture margin was located subgingival. This case report describes a single-tooth rehabilitation involving a combination of root displacement via orthodontic extrusion and crown lengthening. The rehabilitation was followed by post-and-core restoration using a prefabricated glass fiber post associated with a disilicate lithium crown. The clinical decision making and combined effect of both treatment strategies are explained in this report. The treatment required three months, including recovery times after surgery and the placement of the provisional crown. The patient was esthetically and functionally satisfied with the restoration. Patient follow-up examination was performed 24 months after the treatment. This clinical report contributes to the clinical practice and exemplifies the possibility of rehabilitating the natural tooth using combined techniques, which may offer particular advantages regarding prognosis and invested efforts.