TruNatomy: ¿un nuevo instrumento o un concepto diferente? / TruNatomy: a new instrument or a different concept?

La alta incidencia de fracturas dentarias producidas a distancia del tratamiento endodóntico ha llevado a desarrollar cambios en los procedimientos operatorios, con el objeto de conservar la mayor cantidad de estructura dentaria durante la terapia de conductos radiculares. En relación con esta idea, el sistema TruNatomy trabaja sobre el concepto de endodoncia mínimamente invasiva. Una zona altamente sensible a ser considerada es el área pericervical, delimitada 4 mm por encima y 4 mm por debajo de la cresta ósea. El objetivo del presente informe es analizar las propiedades y las características técnicas del sistema de instrumentación Tru- Natomy y los cambios conceptuales que su utilización implica (AU)

The high incidence of dental fractures in the long-term after endodontic treatment has led to analyzed how to change the endodontic procedures to preserve the dental structure during root canal therapy. The TruNatomy system was developed based on the concept of Minimally Invasive Endodontics. A highly sensitive zone to be considered is the pericervical area, restricted to 4 mm above and 4 mm below the bone crest. The objective of this report is to analyze the properties and technical characteristics of the TruNatomy instrumentation system and the changes in the concepts in the clinical treatment procedures as a result of its use (AU)

Resistencia a la Fractura de Dientes Tratados Endodónticamente Obturados con Selladores Biocerámicos Versus Selladores Resinosos. Revisión Sistemática / Fracture Resistance of Endodontically Treated Teeth Obturated with Bioceramic Sealers and Epoxy Resin-Based Sealers. A Systematic Review

RESUMEN: El objetivo de este estudio fue determinar mediante la revisión de la literatura científica disponible cuál es el tipo de cemento sellador que proporciona mayor resistencia a la fractura en dientes tratados endodónticamente, los cementos a base de biocerámicos o los en base a resina epóxica. Se realizó una revisión sistemática de acuerdo a las bases de los estamentos de PRISMA, en las bases de datos Medline, SciELO, Trip Database, LILACS, Web of Science, Cochrane. Se realizó la búsqueda a 10 años y se incluyeron sólo estudios in vitro. Se encontraron 202 artículos, luego se eliminaron los artículos duplicados y se excluyeron los estudios no atingentes por título y resúmenes, quedando ocho artículos que se revisaron a texto completo. En esta etapa se excluyeron dos estudios. Un total seis estudios fueron incluidos en esta revisión. De estos, ninguno encontró diferencia significativas entre cementos selladores a base de biocerámicos y a base de resina epóxica, en cuanto a resistencia a la fractura de los dientes tratados endodónticamente. Sin embargo, en 4 estudios los valores más altos encontrados de resistencia a la fractura estuvieron dados por los selladores en base a resina epóxica. Los artículos seleccionados, teniendo en consideración las limitaciones propias de los estudios in vitro, concluyen que en cuanto a resistencia a la fractura no hay diferencias significativas entre el uso de cementos selladores a base de biocerámicos y cementos selladores a base de resina epóxica en la obturación radicular de dientes tratados endodónticamente.

ABSTRACT: The objective of this study was to determine through the review of scientific literature, the type of sealer that provides the greatest resistance to fracture in endodontically treated teeth. Bioceramic sealer or epoxy resin based sealers were considered for this analysis. A systematic review was performed according to PRISMA, in the databases Medline, SciELO, Trip Database, LILACS, Web of Science, Cochrane. The search was carried out over the last 10 years, and only in vitro studies were included; 202 articles were found and subsequently, duplicate articles were eliminated, non-inferential studies by title and abstracts were excluded, leaving eight articles that were revised to full text. In this stage, two studies were excluded. In total, six studies were included in this review. Of these, none found significant difference between sealer cements based on bioceramics and based on epoxy resin, in terms of resistance to fracture of endodontically treated teeth. However, in 4 studies the highest found values of fracture resistance were given by sealers based on epoxy resin. Taking into account the limitations inherent to in vitro studies, this review concludes that in terms of fracture resistance, there are no significant differences between the use of sealer based on bioceramics and the based on epoxy resin in the root canal obturation.

Restauración post-endodoncia y condición social como factor de preservación dentaria: parte 2 / Post-endodontic restoration and social condition asa factor of tooth preservation. Part 2

El objetivo de este estudio fue conocer el estado dental de piezas endodonciadas en correlación conlas variables de restauración coronaria, estado periodontal, nivel de estudio, condición laboral y acceso a servicios odontológicos. Para ello, se analizó una población de individuos compuesta por sujetos concurrentes a los cursos de posgrado de Endodoncia, del Círculo Odontológico de Córdoba, y al servicio de la Cátedra “B” de Endodoncia de la Facultad de Odontología, Universidad Nacional de Córdoba. Se hicieron tratamientos controlados durante dieciocho meses. La muestra total la conformaron 144 pacientes y se trataron 174 casos. El estudio mostró 37 casos con restauración coronaria definitiva sin fracturas, 52 dientes sin restauración, 21 con fracturas y 1 se perdió. De los dientes restaurados, el55,6 por ciento mostraron periodonto normal; 22,2 por ciento gingivitis, y 22 por ciento periodontitis leve. De los dientes sin restauración, el 3,9 por ciento mostraron periodonto normal; 7,8 por ciento gingivitis; 31,4 por ciento periodontitis leve; 35,3 por ciento periodontitis grave y 21,6 por ciento periodontitis complicada. De los dientes fracturados, el 16,7 por ciento mostraron periodonto normal o gingivitis; 35,3 por ciento periodontitis leve y grave, y un 72,7 por ciento periodontitis complicada. No se demostró asociación entre nivel de estudios, condición laboral y tipo de atención con fracturas de los pacientes, pero los porcentajes sugieren más probabilidad de sufrir fractura en los pacientes de la asistencia pública. El elevado porcentaje de inasistencia a control motivó un análisis específico, del cual se pudo concluir que cuanto más grave la patología periodontal, mayor el porcentaje de inasistencia. El estudio permitió observar desigualdad en el acceso a los servicios odontológicos, dientes no rehabilitados y con compromiso periodontal.

The aim of this study was to know the dental state of endodontic pieces in correlation with different variables such as coronary restoration, periodontic condition, level of study, employment status and access to dental services. A population composed of patients treated in two different postgraduate courses at the Círculo Odontológico de Córdoba and Chair “B” of Endodontics, Faculty of Dentistry,National University of Córdoba were analyzed. Treatments were clinically and radiographicallycontrolled for eighteen months. The total sample included 144 patients and 174 treatments. The studyshowed 37 cases with definitive coronary restoration without fractures, 52 teeth without restoration,21 with fractures, and 1 was lost. From restored teeth, 55.6% showed normal periodontium, 22.2%gingivitis, and 22% mild periodontitis. From teeth without restoration, 3.9% showed normalperiodontitis, 7.8% gingivitis, 31.4% mild periodontitis, 35.3% severe periodontitis and 21.6%complicated periodontitis. From fractured teeth, 16.7% showed normal periodontitis or gingivitis, 35.3% had mild and severe periodontitis, and 72.7% had complicated periodontitis. There has beenno correlation between level of education, work status, and kind of service on patient with fractures,but the percentage suggest that patients in public assistance are more likely to suffer fracture. The highpercentage of non-attendance to control led to a specific analysis, from which it is possible to concludedthat the more severe the periodontal disease, the greater the percentage of non-attendance. The study showed inequality in access to dental services, un rehabilitated teeth and with periodontal compromise.

Odontología en el deporte: ¿sólo un protector bucal?: [Editorial] / Sports dentistry: just a mouthguard deal?: [Editorial]

Muchas veces se interpreta que entre los odontólogos y los deportistas media sólo un protector bucal. Hoy se considera que la odontología es tan importante como la nutrición y la psicología, las cuales integran el equipo médico de entidades deportivas, sobre todo en los ámbitos de alto rendimiento y profesionalismo. La odontología que se practica a los deportistas no difiere de la que se presta a cualquier otro paciente. Las prácticas odontológicas dependen, en todo caso, de las características propias de esa población, las que determinan una atención diferenciada o adaptada. Nuestra tarea abarca la prevención, el diagnóstico y el tratamiento de las distintas patologías y lesiones. La actuación en el área de la atención primaria de la salud nos conecta con deportistas, lo cual aporta experiencias que guían nuestras acciones. En cuanto a los protectores bucales, necesarios en los deportes de contacto, existen diferentes tipos, espesores y características que se adaptan al deporte en cuestión y a la edad de quien lo practica; y también existen diferentes procedimientos para su confección. Por todo esto, debemos apuntar a que los pacientes acudan a nosotros, en lugar de adquirir directamente en los comercios los dispositivos que pueden no ser apropiados.

Many times, it is believed that a mouthguard is all thatseparates athletes from dentists. Dentistry is nowadays consideredto play an important role in medical support of high performance sport teams as well as nutrition or psychologyand more so in professional practice. Dental care providedto athletes is obviously not different from that performed inregular patients.The difference is given by the distinctive features presentedby them, which will require treatment adapted to their specialneeds. As dentists, we also know that our work includesprevention, diagnosis and subsequent treatment of differentlesions and pathologies. Since our field of action is withinprimary health care, an initial consultation with the athletewill provide the information that will guide our counseling, treatment, and regular controls. Regarding physical contact sports where a mouthguard might be indicated, differenttypes, thicknesses and materials are available as well as different processing techniques. All of these possibilities can beused to motivate athletes for dental consultation leading themto avoid standard devices that are sold in sport stores.

Evaluation of fracture torque resistance of orthodontic mini-implants / Resistência de fratura ao torque de mini-implantes ortodônticos

This study sought to assess the fracture torque resistance of miniimplants used for orthodontic anchorage. Five commercially available brands of miniimplants were used (SIN®, CONEXÃO®, NEODENT®, MORELLI®, and FORESTADENT®). Ten miniimplants of each diameter of each brand were tested, for a total 100 specimens. The miniimplants were subject to a static torsion test as described in ASTM standard F543. Analysis of variance (ANOVA) with the Tukey multiple comparisons procedure was used to assess results. Overall, mean fracture strength ranged from 15.7 to 70.4 N·cm. Miniimplants with larger diameter exhibited higher peak torque values at fracture and higher yield strength, regardless of brand. In addition, significant differences across brands were observed when implants were stratified by diameter. In conclusion, larger miniimplant diameter is associated with increased fracture torque resistance. Additional information on peak torque values at fracture of different commercial brands of miniimplants may increase the success rate of this orthodontic anchorage modality.

O objetivo do presente estudo foi avaliar a resistência de fratura ao torque de miniimplantes ortodônticos. Foram utiliza das cinco marcas comerciais (SIN®, CONEXÃO®, NEODENT®, MORELLI® e FORESTADENT®). Para cada diâmetro, de cada marca comercial, foram testados 10 miniimplantes, totalizando 100 amostras. Os miniimplantes foram submetidos a um Ensaio Estático de Torção, conforme a norma técnica ASTM F543. Os resultados foram submetidos à Análise de Variância (ANOVA) complementado pelo teste de compa rações múltiplas de Tukey. Os valores médios de resistência de fratura ao torque variaram de 15,7 a 70,4 N·cm e miniimplantes de maior diâmetro apresentaram maiores valores de torque máximo de fratura e de limite de escoamento, independente da marca comercial. Além disso, foram obser vadas diferenças significativas entre as marcas comerciais quando agrupadas de acordo com o diâmetro. Concluise que miniimplantes de maior diâmetro apresentaram maiores valores de resistência de fratura ao torque. Informações sobre o torque máximo de fratura das diferentes marcas comerciais podem aumentar o índice de sucesso deste método de ancoragem ortodôntica.

Effects of alpha-tocopherol on fracture resistance after endodontic treatment, bleaching and restoration

Abstract This study evaluated the effects of 10% alphatocopherol on the fracture resistance of endodontically treated teeth subjected to tooth bleaching with hydrogen peroxide and immediately restored with composite resin. Fifty bovine incisors were selected, including 10 sound teeth that constituted the control group (G1 (C)). The remaining 40 teeth, which were endodontically treated, were divided into four groups (n = 10): G2 (CR), consisting of teeth immediately restored with composite resin; G3 (HP + CR), consisting of teeth subjected to tooth bleaching with 38% hydrogen peroxide and immediately restored with composite resin; G4 (HP + SA + CR), which received treatment similar to that used for G3, but with 10% sodium ascorbate gel applied after the bleaching protocol; and G5 (HP + AT + CR), which was similar to G4 but included 10% alphatocopherol gel as an antioxidant. After 24 h, composite restorations were performed, and teeth were subjected to a fracture resistance test at a speed of 0.5 mm/min in an electromechanical testing machine. The axial force was applied with an angle of incidence of 135° relative to the long axis of the root. Data were subjected to ANOVA and Tukey tests (p = 0.05). G1 exhibited the highest fracture resistance (p < 0.05). No significant differences among the other experimental groups were observed. The 10% sodium ascorbate and 10% alphatocopherol gels did not improve the fracture resistance of endodontically treated teeth subjected to bleaching with 38% hydrogen peroxide.

Diagnóstico y tratamiento de las fracturas dentarias asociadas a la parafunción: parte 3 / Diagnosis and management of fractures teeth associated with parafunction: part 3

Presentar un tratamiento preventivo que consiste en la realización de un ajuste oclusal y de una placa neuromiorrelajante, en un paciente con facetas de desgaste debidas a parafunción. Caso clínico: un paciente de 28 años de edad consultó por un control. Se observaron facetas de desgaste patológicas en el esmalte de la pieza dentaria 4.7, con una relación cúspide/fosa profunda, por lo que se decidió realizar una remodelación oclusal y confeccionar una placa de protección neuromiorrelajante, a fin de evitar una posible fractura de la pieza. Conclusión: un diagnóstico correcto y temprano de las facetas dentarias patológicas en el esmalte y su posible tratamiento son fundamentales para evitar opsibles fracturas dentarias asociadas a la parafunción...

Evaluación de la adhesión de postes: ¿son útiles los datos disponibles? / Evaluation of posts bonding: is the available data useful?

La restauración del diente endodónticamente tratado ha sido estudiada desde todos los aspectos posibles, que incluyen consideraciones biológicas, biomecánicas ye stétias. Esto implica un profundo conocimiento de materiales y técnicas. Uno de los aspectos que se han evaluado de múltiples maneras es la adhesión de los sistemas de anclaje intrarradicular. La evaluación de la adhesión incluye ensayos mecánicos, infiriendo que cuanto más elevada sea, mejor va a ser su resistencia al asentamiento, endurecimiento y comportamiento clínico. Estos estudios suelen completarse con evaluaciones cualitativas, como observaciones microscópicas. Sin embargo, el diseño de este tipo de estudios presenta algunos desafíos. Esta editorial intenta presentar el tema desde su utilidad y dificultades

Fracturas coronarias con exposición pulpar: reporte de tres casos clínicos en diferentes edades / Crown fractures with pulp exposure: report of three clinical cases at different ages

Los traumatismos dentarios son la causa más frecuente de daño en los dientes anteriores. Las fracturas coronarias con pulpa expuesta representan entre el 18 al 20 por ciento de las lesiones traumáticas que involucran las piezas dentarias. En esta comunicación clínica, los autores muestran un tratamiento preventivo: técnica de Cvek, que evita que los dientes afectados llegen a un tratamiento endodóntico total

Análisis comparativo de la resistencia a la fatiga en elementos dentarios tratados endodónticamente utilizando pernos de fibra de vidrio / Comparative analysis of fatigue resistance in endodontically treated dental elements using fiberglass posts

El objetivo de este estudio fue establecer entre las diferentes morfologías radiculares, la cantidad de raíces y la forma específica de cada perno de fibra de vidrio en incisivos y premolares. Para ello, se utilizaron 90 dientes recientemente extraídos por razones ortodóncicas o patología periodontal (incisivos y premolarespermanentes), y se conformaron 7 grupos experimentales Coltene Whaledent). grupo 6: primeros premolares superiores birradicularescon pernos cilíndricos-cónicos (glassis, glassix Switzerland). grupo 7: control. a las piezas dentarias experimentalesse les cortó la porción coronaria a 3 mm de la unión amelocementaria, se los trató endodónticamente y se utilizaron pernos de fibra de vidrio para reconstruirlos. en 3 de los grupos fueron utilizados pernos cilíndricos y en los otros 3 grupos, pernos cilíndrico-cónicos. Se reconstruyeron los muñones con resinas y posteriormente, se les realizó una corona metálica. luego, fueron sometidos a pruebas de carga para analizar la resistencia a la fatigadel remanente dentario, manteniendo sin cambios las variables de acondicionamiento, cementado, tipo de cementos, reconstrucción de muñón, cementado de corona y tipo de corona. a los resultados se les realizó el análisis de varianza, con el propósito de valorarla implicancia clínica al momento de seleccionar el perno en relación a la anatomía del conducto de la pieza a rehabilitar. Resultados: en los grupos de ICS mostraron mayor resistencia a lafatiga las muestras restauradas sin pernos. en los ICI y Pm no se observaron diferencias significativas en el uso de PFV cilindrocónicos y cilíndricos. en el grupo control donde las muestras se reconstruyeron perno las fracturas fueron longitudinales y seprodujeron a nivel del cuello. Sin embargo, en los grupos de trabajo,las fracturas fueron en algunos casos longitudinales y en otras, oblicuas.

Effect of different restorative procedures on the fracture resistance of teeth submitted to internal bleaching

The aim of this study was to evaluate the influence of different restorative procedures on the fracture resistance of endodontically treated teeth submitted to intracoronal bleaching. Fifty upper central incisors were distributed into 5 groups: GI - healthy teeth; GII - endodontically treated teeth sealed with Coltosol; GIII - endodontically treated teeth bleached and sealed with Coltosol; GIV - endodontically treated teeth bleached and restored with composite resin; and GV - endodontically treated teeth bleached and restored with a fiberglass post and composite resin. In the bleached specimens, a cervical seal was made prior to bleaching with 38% hydrogen peroxide. The gel was applied on the buccal surface and in the pulp chamber, and was then light-activated for 45 s. This procedure was repeated three times per session for four sessions, and each group was submitted to the restorative procedures described above. The specimens were submitted to fracture resistance testing in a universal testing machine. There were statistically significant differences among the groups (p < 0.05). The mean value found for GIII was the lowest (0.32 kN) and was significantly different from the values found for GI (0.75 kN), GII (0.67 kN), GIV (0.70 kN), and GV (0.72 kN), which were not significantly different from each other (p > 0.05). The restorative procedures using composite resin were found to successfully restore the fracture resistance of endodontically treated and bleached teeth.

Análisis de la resistencia flexural a la fractura de restauraciones coronarias completas anteriores e porcelana pura (AU) / Analysis of the flexural fracture resistance of anterior all-ceramic crowns

Propósito: la influencia del tallado de diferentes diseños de la terminación marginal de la preparación dentaria y distintos espesores incisaless sobre la resistencia a la fractura de los sistemas de cerámica pura estudiados, es actualmente controvertida. Objetivo: el propósito de este estudio fue realizar una investigación in vitro para determinar la resistencia a la fractura de restauraciones coronarias completas de tres sistemas cerámicos estudiados, sobre preparaciones simuladas de incisivos centrales superiores. Materiales y métodos: se evaluaron tres sistemas de cerámica pura, con dos tallados diferentes de la terminación periférica de la preparación dentaria y dos espesores incisales cerámicos distintos. Se realizaron pilares metálicos como modelos de trabajo para evaluar la resistencia a la fractura, que fueron acondicionados para establecer condiciones reproducibles y una efectiva transferencia de fuerzas simulando una unión adhesiva completa entre la corona y las estructuras de los pilares que la soportan.

Ex-vivo evaluation of the intrapulpal temperature variation and fracture strength in teeth subjected to different external bleaching protocols

This study evaluated the influence of bleaching protocols on intrapulpal temperature and fracture strength of the bleached teeth. Ninety maxillary incisors were assigned to 9 groups (n=10): G1: 35 percent carbamide peroxide (35 percent CP), G2: 38 percent hydrogen peroxide (38 percent HP), G3: halogen light, G4: LED-laser, G5: 35 percent CP + halogen light, G6: 38 percent HP + halogen light, G7: 35 percent CP + LED-laser, G8: 38 percent HP + LED-laser, and G9: no treatment (control). Pulp space was widened, a thermocouple was introduced through the apex up to the pulp chamber and the temperature was recorded (°C). The fracture strength (kN) was determined using an Instron machine. Data were analyzed by ANOVA and Tukey's test (p<0.05). The halogen light alone (1.10 ± 0.24) (G3) and associated with 38 percent HP (1.15 ± 0.30) (G6) produced the highest temperature increase, statistically different (p<0.05) from the other groups. G1 (0.15 ± 0.06) and G6 (0.19 ± 0.07) produced the lowest values, statistically different (p<0.05) from G5 (0.65 ± 0.49). The bleaching protocols increased the temperature, but no increment exceeded the critical value of 5.6°C. Neither 35 percent CP nor 38 percent HP or the light sources alone altered the fracture strength of the teeth.

Este estudo avaliou a influência de protocolos de clareamento na temperatura intrapulpar e resistência à fratura de dentes clareados. Noventa incisivos superiores foram divididos em 9 grupos (n=10): G1: peróxido de carbamida a 35 por cento (PC 35 por cento), G2: peróxido de hidrogênio a 38 por cento (PH 38 por cento), G3: luz halógena, G4: LED-laser, G5: PC 35 por cento + luz halógena, G6: PH 38 por cento + luz halógena, G7: PC 35 por cento + LED-laser, G8: PH 38 por cento + LED-laser e G9: sem tratamento (controle). O canal radicular foi alargado, um termopar foi introduzido no ápice até a câmara pulpar e a temperatura foi calculada (°C). A resistência à fratura (kN) foi determinada em máquina Instron. Os dados foram analisados por análise de variância e teste de Tukey (p>0,05). A luz halógena utilizada isoladamente (1,10 ± 0,24) (G3) e associada ao PH 38 por cento (1,15 ± 0,30) (G6) proporcionaram os maiores valores de temperatura, sendo estatisticamente diferentes dos demais grupos (p<0,05). O G1 (0,15 ± 0,06) e o G6 (0,19 ± 0,07) produziram os menores valores de resistência à fratura, sendo estatisticamente diferentes (p<0,05) do G5 (0,65 ± 0,49). Os protocolos de clareamento aumentaram a temperatura, mas nenhum incremento excedeu o valor crítico de 5,6oC. O PC 35 por cento, PH 38 por cento e as fontes de luz utilizadas isoladamente não alteraram a resistência à fratura dos dentes.

Fracture resistance of teeth subjected to internal bleaching and restored with different procedures

This study evaluated the fracture resistance of teeth submitted to internal bleaching and restored with different procedures. Forty maxillary incisors were endodontically treated and assigned to 4 groups (n=10): G1- restored with composite resin (CR), G2- bleached with hydrogen peroxide (HP) and restored with CR, G3- restored with CR and fiberglass posts (CR + posts) and G4- bleached and restored with CR + posts. HP was applied in the buccal surface and pulp chamber 3 times at each one of 2 sessions with an interval of 7 days between them. Additional 10 sound incisors were subjected to fracture strength test (gold standard). The fracture strength (kN) was determined in an Instron machine. Data were analyzed by ANOVA and Tukey-Kramer test (α=0.05). The untreated teeth (gold standard) showed the highest (p<0.05) fracture strength (0.43 ± 0.16). Teeth restored with CR (G1) without internal bleaching had the lowest (p<0.05) fracture strength (0.23 ± 0.11). Teeth bleached and restored with CR (G2) (0.26 ± 0.10), restored with CR + posts ithout internal bleaching (G3) (0.31 ± 0.17) and, bleached and restored with CR + posts (G4) (0.33 ± 0.12) had intermediate values, sometimes similar to the group with the highest value, sometimes similar to the group with the lowest value. In conclusion, as far as the fracture strength is concerned, teeth subjected to internal bleaching can be restored with composite resin alone, as the use of posts in these teeth did not increase their resistance.

Este estudo avaliou a resistência à fratura de dentes submetidos ao clareamento interno restaurados com diferentes procedimentos. Quarenta incisivos superiores foram tratados endodonticamente e divididos em 4 grupos (n = 10): G1- restaurados com resina composta (RC), G2- clareados com peróxido de hidrogênio (PH) e restaurados com o RC, G3- restaurado com RC e pinos de fibra de vidro (RC + pinos) e G4- clareados e restaurados com RC + pinos. O PH foi aplicado na superfície vestibular e câmara pulpar 3 vezes por sessão, por 2 sessões com intervalo de 7 dias entre elas. Dez dentes hígidos adicionais foram submetidos a teste fratura (padrão ouro). A resistência à fratura (kN) foi determinada em máquina Instron. Os dados foram analisados por Análise de Variânica e teste de Tukey-Krammer (α= 0,05). Os dentes não tratados (padrão ouro) apresentaram a maior resistência à fratura (0,43 ± 0,16) (p <0,05). Os dentes restaurados com RC (G1) apresentaram a menor resistência à fratura (0,23 ± 0,11) (p <0,05). Os dentes clareados e restaurados com RC (G2) (0,26 ± 0,10), restaurado com RC + pinos (G3) (0,31 ± 0,17) e os clareados e restaurados com RC + pinos (G4) (0,33 ± 0,12) apresentaram valores intermediários, ora semelhantes ao do grupo com o maior valor, ora similares ao grupo de valores mais baixos. Pode-se concluir que os dentes submetidos ao clareamento interno podem ser restaurados com apenas resina composta.

Fracture resistance of weakened teeth restored with condensable resin with and without cusp coverage

OBJECTIVES: This in vitro study evaluated the fracture resistance of weakened human premolars (MOD cavity preparation and pulp chamber roof removal) restored with condensable resin composite with and without cusp coverage. MATERIAL AND METHODS: Thirty human maxillary premolars were divided into three groups: Group A (control), sound teeth; Group B, wide MOD cavities prepared and the pulp chamber roof removed and restored with resin composite without cusp coverage; Group C, same as Group B with 2.0 mm of buccal and palatal cusps reduced and restored with the same resin. The teeth were included in metal rings with self-curing acrylic resin, stored in water for 24 h and thereafter subjected to a compressive axial load in a universal testing machine at 0.5 mm/min. RESULTS: The mean fracture resistance values ± standart deviation (kgf) were: group A: 151.40 ± 55.32, group B: 60.54 ± 12.61, group C: 141.90 ± 30.82. Statistically significant differences were found only between Group B and the other groups (p<0.05). The condensable resin restoration of weakened human premolars with cusp coverage significantly increased the fracture resistance of the teeth as compared to teeth restored without cusp coverage. CONCLUSION: The results showed that cusp coverage with condensable resin might be a safe option for restoring weakened endodontically treated teeth.

Fracture strength of teeth restored with ceramic inlays and overlays

This study evaluated the fracture strength of teeth restored with bonded ceramic inlays and overlays compared to sound teeth. Thirty sound human maxillary premolars were assigned to 3 groups: 1- sound/unprepared (control); 2- inlays and 3- overlays. The inlay cavity design was Class II MOD preparation with an occlusal width of 1/2 of the intercuspal distance. The overlay cavity design was similar to that of the inlay group, except for buccal and palatal cusp coverage The inlay and overlay groups were restored with feldspathic porcelain bonded with adhesive cement. The specimens were subjected to a compressive load until fracture. Data were analyzed statistically by the Kruskal-Wallis test at 5 percent significance level. The fracture strength means (KN) were: Sound/unprepared group = 1.17, Inlay group= 1.17, and Overlay group = 1.14. There were no statistically significant differences (p>0.05) among the groups. For inlays and overlays, the predominant fracture mode involved fragments of one cusp (70 percent of simple fractures). The fracture strength of teeth restored with inlay and overlay ceramics with cusp coverage was similar to that of intact teeth.

Este estudo avaliou a resistência à fratura de dentes restaurados com inlays e overlays de cerâmicas comparadas a dentes íntegros. Trinta pré-molares humanos íntegros foram divididos em 3 grupos: 1-Dentes sem preparo cavitário (controle), 2-Inlays e 3-Overlays. O preparo para as inlays apresentava uma cavidade de Classe II MOD tendo caixa oclusal com largura de metade da distância intercuspídica. O preparo para as overlays era semelhante ao das inlays; porém com cobertura das cúspides vestibular e palatina. Os grupos 2 e 3 foram restaurados com porcelanas feldspáticas fixadas com cimento resinoso. As amostras foram submetidas à compressão até a fratura. Os valores médios de fratura (KN) foram: grupo 1 = 1,17, grupo 2 = 1,17 e grupo 3 = 1,14. O teste de Kruskal-Wallis não revelou diferença estatisticamente significante entre os 3 grupos (p>0,05). Para as inlays e overlays, a predominância das fraturas envolveu fragmentos de uma das cúspides (70 por cento de fraturas simples). Concluiu-se que os dentes restaurados com inlays e overlays apresentaram resistência da cúspide comparável aos dentes intactos.

Influence of intraradicular post and crown ferrule on the fracture strength of endodontically treated teeth

The aim of this study was to investigate the fracture strength of endodontically treated teeth restored with different posts and variable ferrule heights. Sixty freshly extracted human canines were treated endodontically and randomly assigned to 6 groups (n=10), being restored with custom-made cast post-and-core (CP0 and CP3 groups), prefabricated post and composite resin core (PF0 and PF3 groups), and composite resin (CR0 and CR3 groups). The CP0, PF0 and CR0 groups presented no ferrule and the CP3, PF3 and CR3 presented 3 mm of coronal structure. All teeth were restored with full metal crowns. The fracture strength was measured in a universal testing machine at 45o to the long axis of the tooth until failure. Data were analyzed statistically by 2-way ANOVA and Tukey's test (?=0.05). When the mean fracture strength values were compared (CP0 group - 820.20 N, CP3 group - 1179.12 N; PF0 group - 561.05 N; PF3 group - 906.79 N; CR0 group - 297.84 N; and CR3 group - 1135.15 N) there was statistically significant among the groups (p<0.05), except for the three groups with 3 mm of coronal remaining, which were similar to each other. The results of this study showed that the ferrule in crowns promoted significantly higher fracture strength in the endodontically treated teeth.

O objetivo neste estudo foi avaliar a resistência à fratura de dentes tratados endodonticamente restaurados com diferentes pinos e diferentes alturas de remanescente dentinário da coroa. Sessenta caninos recém-extraídos foram tratados endodonticamente, separados em 6 grupos (n=10) e restaurados com núcleo metálico fundido (CP0 e CP3), pino pré-fabricado e núcleo em resina composta (PF0 e PF3) ou resina composta (CR0 e CR3). Os grupos CP0, PF0 e CR0 não possuíam férula e os grupos CP3, PF3 e CR3 apresentaram 3 mm de remanescente coronário. Todos os dentes foram restaurados com coroas totais metálicas. A resistência à fratura foi medida em máquina universal de ensaios com o longo eixo do dente posicionado a 45 graus em relação ao carregamento axial, até que ocorresse fratura. A análise de variância 2 critérios (?=0,05) mostrou diferença estatisticamente significativa entre os grupos. Quando as médias das forças para fratura foram comparadas (CP0 = 820,0 N; CP3= 1179,12 N; PF0 = 561,05 N; PF3 = 906,79 N; CR0 = 297,84 N; e CR3 = 1135,15 N) não foram observadas diferenças significativas entre os 3 grupos com 3 mm de remanescente coronal. Os resultados mostraram que a presença de férula em coroas aumenta significantemente a resistência à fratura de dentes tratados endodonticamente.

The effect of post-core and ferrule on the fracture resistance of endodontically treated maxillary central incisors.

AIM: To evaluate the effect of post reinforcement, post type and ferrule on the fracture resistance of endodontically treated maxillary central incisors. MATERIALS AND METHODS: Sixty central incisor teeth were selected and grouped into six groups, viz. A, B, C, D, E, and F, each consisting of 10 specimens. Group A specimens were not subjected to any restorative treatment. Group B specimens were endodontically treated and crowned. Specimens of groups C and D were restored with custom cast post and core. Specimens of groups E and F were treated with prefabricated titanium post and composite core. Specimens of groups C and E were restored with porcelain-fused metal (PFM) crown having 2 mm ferrule. Specimens of groups D and F were restored with PFM crown having no ferrule. All the specimens were subjected to load (newton, N) on the lingual surface at a 135 degree angle to the long axis with a universal testing machine until it fractured. The fracture load and mode of fracture of each specimen were noted. One-way analysis of variance with Tukey honestly significant difference procedure was employed to identify the significant difference among the groups at 5% level (P < 0.05). RESULTS: There were significant differences among the six groups studied (P < 0.0001). The highest fracture strength was recorded with specimen of group C (1376.7 N). There were significant differences between groups A and D versus groups B, E, and F. There were no significant differences between groups B, E, and F. Cervical root fracture was the predominant mode of failure in all the groups except group A. CONCLUSION: The results showed that endodontically treated teeth restored with custom cast post core were as strong as the untreated group. Teeth restored with custom cast post core were better resistant to fracture than teeth restored with prefabricated titanium post and composite core. Ferrule is more important in custom cast post core than in prefabricated post and composite core.

Fracture resistance of weakened roots restored with composite resin and glass fiber post

This study evaluated the fracture resistance of weakened roots restored with glass fiber posts, composite resin cores and complete metal crowns. Thirty maxillary canines were randomly divided into 3 groups of 10 teeth each: teeth without weakened roots (control); teeth with partially weakened roots (PWR) and teeth with and largely weakened roots (LWR). The control group was restored with glass fiber posts and a composite resin core. Teeth in the PWR and LWR groups were flared internally to standardized dimensions in order to simulate root weakness. Thereafter, the roots were partially filled with composite resin and restored in the same way as in the control group. The specimens were exposed to 250,000 cycles in a controlled chewing simulator. All intact specimens were subjected to a static load (N) in a universal testing machine at 45 degrees to the long axis of the tooth until failure. Data were analyzed by one-way ANOVA and Dunnett's test for multiple comparisons (p=0.05). There were statistically significant difference differences (p<0.01) among the groups (control group = 566.73 N; PWR = 409.64 N; and LWR = 410.91 N), with significantly higher fracture strength for the control group. There was no statistically significant difference (p>0.05) between the weakened groups. The results of this study showed that thicker root dentin walls significantly increase the fracture resistance of endodontically treated teeth.

Este estudo avaliou a resistência à fratura de raízes fragilizadas restauradas com pinos de fibra de vidro, núcleos de resina composta e coroas totais metálicas. Trinta caninos superiores foram aleatoriamente divididos em 3 grupos. Dentes sem enfraquecimento (grupo controle); grupo de raízes parcialmente enfraquecidas e amplamente enfraquecidas. O grupo controle foi restaurado com pinos de fibra de vidro e núcleo em resina composta. Os dentes dos grupos de raízes parcialmente e amplamente enfraquecidas foram internamente preparadas de maneira padronizada simulando enfraquecimento. Após isto, as raízes foram parcialmente preenchidas com resina composta e restauradas como no grupo controle. Os espécimes foram expostos a 250.000 ciclos em uma máquina de ciclagem mecânica. Todos os dentes intactos foram submetidos à carga estática (N) em uma máquina de ensaio universal a 45 graus ao longo eixo do dente até a sua falha. Os resultados foram analisados através do teste ANOVA a 1 critério e teste de Dunnett para comparações múltiplas (p=0,05). A análise estatística revelou diferenças significantes (p<0,01) entre os três grupos (grupo controle = 566,73 N; RPE = 409,64 N; e ERA = 410,91 N). Quando as três médias de resistência a fratura são ranqueadas as duas menores não se diferem. Os resultados deste estudo mostraram que uma maior espessura de paredes dentinárias aumenta significantemente a resistência à fratura de dentes tratados endodonticamente.

Propriedades flexurais de pinos diretos metálicos e não-metálicos / Flexural properties of direct matallic and metal free posts

Com a evolução dos materiais restauradores, novas técnicas, que buscam preservar ao máximo a estrutura dentária remanescente de dentes tratados endodonticamente, vêm surgindo. O objetivo deste trabalho foi medir e comparar a resistência à flexão entre pinos pré-fabricados diretos metálicos (aço inoxidável) e não-metálicos (quatro marcas comerciais de pinos de fibra de vidro, uma de fibra de carbono e uma marca de fibra de quartzo). Estes pinos foram testados em uma máquina de ensaio universal Pantec 500 (Panambra), de acordo com as especificações da ISO 178 para testes transversais de três pontos. Baseado na análise estatística aplicada aos dados obtidos ao final do estudo conclui-se que: todos os grupos tiveram valores médios do módulo flexural superiores ao módulo da dentina relatado na literatura; os pinos poliméricos reforçados por fibras obtiveram resistência máxima flexural superior à dos pinos metálicos e não houve diferenças significativas entre os grupos, em relação ao módulo flexural.