Effect of intracanal diode laser irradiation on fracture resistance of roots restored with CAD/CAM posts

Aim: To evaluate the fracture resistance of roots restored with CAD/CAM-fabricated posts, receiving or not intracanal laser treatment, compared with glass fiber posts under mechanical cycling. Methods: Twenty-seven endodontically treated, single-rooted teeth were divided into 3 groups: group 1 (control), prefabricated glass fiber posts relined with resin composite; group 2, CAD/CAM-fabricated intraradicular posts using Resin Nano Ceramic (RNC) blocks; and group 3, CAD/CAM-fabricated intraradicular posts using RNC blocks in canals irradiated with a 940-nm diode laser (100 mJ, 300-um optic fiber, coronal-apical and apical-coronal helical movements, speed of 2 mm/second, 4 times each canal). After cementation of the coping, cyclic loading was applied at an angle of 135° to the long axis of the root, with a pulse load of 130 N, frequency of 2.2 Hz, and 150,000 pulses on the crown at a point located 2 mm below the incisal edge on the lingual aspect of the specimen. Every 50,000 cycles, the specimens were evaluated for root fracture occurring below or above the simulated bone crest. Results were analyzed by one-way ANOVA followed by Tukey's test (p<0.05). Results: Group 1 was the least resistant, while groups 2 and 3 were the most resistant. Group 1 differed significantly from groups 2 and 3 (p<0.01), but there was no difference between groups 2 and 3 (p<0.01). Conclusion: Treatment of the intracanal surface with diode laser had no influence on fracture resistance of roots restored with CAD/CAM-fabricated posts, but a longer cycling time is required to evaluate the real benefits of diode laser irradiation

Abordagem multidisciplinar no tratamento de incisivo lateral com fratura oblíqua e lesão periapical: relato de caso clínico / Multidisciplinary approach in the treatment of lateral incisor with oblique fracture and periapical injury: clinical case report

Casos de fraturas dentárias oblíquas muitas vezes possuem um prognóstico desfavorável, geralmente com indicação da extração do elemento dental. O presente artigo visou relatar o tratamento do caso clínico de um paciente do sexo masculino, 12 anos, que compareceu à Unidade de Saúde Bucal do Hospital Universitário de Brasília com encaminhamento de extração do dente 12, apresentando fratura oblíqua que se estendia subgengivalmente na face vestibular. O trauma havia ocorrido há três anos e o paciente havia sido submetido a diversas intervenções endodônticas, apresentando no momento da consulta inicial por nossa equipe uma lesão periapical extensa. Após a realização da anamnese, exame clínico e radiográfico, foi adotada uma abordagem multidisciplinar conservadora com a manutenção do dente e a realização da enucleação da lesão periapical por meio de intervenção cirúrgica e posterior reabilitação. Em uma mesma sessão, foi realizada a obturação do conduto com cone de guta percha e cimento sealer 26 e a cirurgia parendodôntica juntamente com a apicoplastia. Uma semana após a intervenção cirúrgica foi realizada restauração classe IV com resina composta baseada no enceramento dos modelos de diagnóstico montados em articulador. Com base em uma avaliação criteriosa e multidisciplinar, foi possível adotar uma abordagem conservadora no caso em questão, com a manutenção e reabilitação de um dente permanente em um paciente jovem, evitando a indicação de exodontia(AU)

Cases of oblique dental fractures often have an unfavorable prognosis, usually with the indication of extraction of the dental element. The present article aimed to report the treatment of the clinical case of a 12-year-old male patient, who attended the Oral Health Unit of the Hospital Universitário de Brasília with a referral for extraction of tooth 7, presenting an oblique fracture that extended subgingivally on the labial surface. The trauma had occurred three years ago and the patient had undergone several endodontic interventions, presenting an extensive periapical lesion at the time of the initial consultation by our team. After anamnesis, clinical and radiographic examination, a conservative multidisciplinar approach was adopted with the maintenance of the tooth and the enucleation of the periapical lesion through surgical intervention and subsequente rehabilitation. In the same session, the conduit was filled with gutta-percha cone and sealer cement 26 and parendodontic surgery was performed together with apicoplasty. One week after the surgical intervention, class IV restoration was performed with composite resin based on the waxing of the diagnostic models mounted on an articulator. Based on a careful and multidisciplinary evaluation, it was possible to adopt a conservative approach in the case in question, with the maintenance and rehabilitation of a permanent tooth in a young patient, avoiding the indication of extraction(AU)

Age-Related Pattern of Dental Trauma in a Nigerian Tertiary Health Institution

Abstract Objective: To evaluate the pattern of traumatic dental injuries among children, adolescents, and adults. Material and Methods: This was a cross-sectional analytic study of children and adults who presented with dental trauma. Data utilized for this study were sociodemographic characteristics, history of the traumatic incident, presenting complaints, traumatized teeth and classification of the traumatized tissues using Ellis and Davey's classification. Results: A total of 163 participants with 307 traumatized teeth were included in the study. The participants' age ranged from 2 years to 75 years, with a mean age of 25.36 ±15.4 years. Children <10 years were the least represented (14.7%), adolescents 10-19 years accounted for 23.9%., young adults 20 to 40 years were the most represented (44.8%) and older adults >40 years (16.6%). A higher proportion of the study participants were female 83 (50.9%) and the most prevalent complaint was broken teeth (57.1%) The most prevalent aetiology of the trauma documented was fall (36.2%). The most prevalent injury type was extended crown fracture with noticeable dentinal involvement without pulp exposure. There was a statistically significant association between injury type, aetiology and age group. Conclusion: Traumatic dental injuries affect children, adolescents and adults alike. The central incisors were the most vulnerable teeth across all age groups. Age was significantly associated with the etiology of dental trauma and injury type (AU).

Fatores relacionados à fratura de dentes tratados endodonticamente / Factors related to fracture of treated teeth endodonticly

A longevidade de dentes tratados endodonticamente é um assunto amplamente discutido no campo de atuação da odontologia restauradora e envolve questões que vão além do alcance da endodontia. Não são raras as situações em que um dente reabilitado após a terapia endodôntica apresenta fratura corono- radicular, podendo comprometer sua viabilidade. Considerando o custo biológico envolvido na perda dentária, ou o custo material empregado para que os tratamentos sejam refeitos, é importante que os cirurgiões dentistas estejam capacitados a traçar o adequado plano de tratamento. O planejamento restaurador representa divergências de opinião, tanto na prática clínica quanto em âmbito científico, considerando-se as variáveis envolvidas como perda estrutural, ausências dentárias, posicionamento do dente no arco, número e localização das cúspides perdidas, presença ou não de retentor intra-radicular, representam papel importante na longevidade do tratamento restaurador e devem ser individualmente analisadas. Diante do cenário descrito, o objetivo deste estudo foi avaliar os fatores relacionados à fratura de dentes tratados endodonticamente. Através dessa revisão da literatura, conclui-se que a variável estrutural, relacionada à sua função mastigatória é a principal responsável no prognóstico dos dentes tratados endodonticamente. Por este motivo deve ser prioritariamente considerada ao se eleger o procedimento restaurador. É de extrema importância que a comunidade de cirurgiões dentistas disponha de conhecimento técnico e científico atual para pautar suas escolhas na prática clínica, embasando a análise individual do planejamento restaurador dos dentes tratados endodonticamente.

The longevity of endodontically treated teeth is a widely discussed subject in the field of restorative dentistry and it has issues that go beyond the scope of endodontics. It is not uncommon for a tooth rehabilitated to present a crown-root fracture, which may compromise its viability, after endodontic therapy. Considering the biological cost involved in tooth loss, or the material cost used for treatments to be redone, it is important that dental surgeons are able to draw up the appropriate treatment plan. Restorative planning still represents differences of opinion, both in clinical practice and in the scientific field, considering the variables involved such as structural loss, dental absences, tooth positioning in the arch, number and location of lost cusps, presence or not of intraretainer. -radicular, among countless other clinical variables, play an important role in the longevity of the restorative treatment and must be individually analyzed. The aim of this study was to evaluate the factors related to the fracture of endodontically treated teeth. Through this literature review, we concluded that the structural variable, related to its masticatory function, is the main responsible for the prognosis of endodontically treated teeth. For this reason, it should be considered as a priority when choosing the restorative procedure. It is extremely important that the community of dental surgeons have current technical/scientific knowledge to guide their choices in clinical practice, basing the individual analysis of the restorative planning of endodontically treated teeth.

Fracture resistance of simulated immature teeth reinforced with different mineral aggregate-based materials

Abstract This study assessed the fracture resistance of simulated immature teeth reinforced with calcium aluminate cement (CAC) or mineral trioxide aggregate (MTA) containing calcium carbonate nanoparticles (nano-CaCO3). The microstructural arrangement of the cements and their chemical constitution were also evaluated. Forty-eight canines simulating immature teeth were distributed into 6 groups (n=8): Negative control - no apical plug or root canal filling; CAC - apical plug with CAC; CAC/nano-CaCO3 - apical plug with CAC+5% nano-CaCO3; MTA - apical plug with MTA; MTA/nano-CaCO3 - apical plug with MTA+5% nano-CaCO3; and Positive control - root canal filling with MTA. The fracture resistance was evaluated in a universal testing machine. Samples of the cements were analyzed under Scanning Electron Microscope (SEM) to determine their microstructural arrangement. Chemical analysis of the cements was performed by Energy Dispersive X-ray Spectroscopy (EDS). The fracture resistance of CAC/nano-CaCO3 was significantly higher than the negative control (p<0.05). There was no significant difference among the other groups (p>0.05). Both cements had a more regular microstructure with the addition of nano-CaCO3. MTA samples had more calcium available in soluble forms than CAC. The addition of nano-CaCO3 to CAC increased the fracture resistance of teeth in comparison with the non-reinforced teeth. The microstructure of both cements containing nano-CaCO3 was similar, with a more homogeneous distribution of lamellar- and prismatic-shaped crystals. MTA had more calcium available in soluble forms than CAC.

Resumo Este estudo avaliou a resistência à fratura de dentes imaturos simulados reforçados com cimento de aluminato de cálcio (CAC) ou trióxido agregado mineral (MTA) contendo nanopartículas de carbonato de cálcio (nano-CaCO3). O arranjo microestrutural dos cimentos e sua constituição química também foram avaliados. Quarenta e oito caninos simulando dentes imaturos foram distribuídos em 6 grupos (n=8): Controle negativo - sem plug apical ou obturação do canal radicular; CAC - plug apical com CAC; CAC/nano-CaCO3 - plug apical com CAC + 5% nano-CaCO3; MTA - plug apical com MTA; MTA/nano-CaCO3 - plug apical com MTA + 5% nano-CaCO3; e Controle positivo - obturação dos canais radiculares com MTA. A resistência à fratura foi avaliada em máquina universal de ensaios. Amostras dos cimentos foram analisadas em Microscópio Eletrônico de Varredura (MEV) para determinar seu arranjo microestrutural. A análise química dos cimentos foi realizada por Espectroscopia de Energia Dispersiva de Raio-X (EDS). A resistência à fratura de CAC/nano-CaCO3 foi significativamente maior do que o controle negativo (p<0,05). Não houve diferença significativa entre os outros grupos (p>0,05). Ambos os cimentos apresentaram microestrutura mais regular com a adição de nano-CaCO3. As amostras de MTA apresentaram mais cálcio disponível em formas solúveis do que CAC. A adição de nano-CaCO3 ao CAC aumentou a resistência à fratura dos dentes em comparação aos dentes não reforçados. A microestrutura de ambos os cimentos contendo nano-CaCO3 foi semelhante, com uma distribuição mais homogênea de cristais de formato lamelar e prismático. MTA apresentou mais cálcio disponível nas formas solúveis do que CAC.

Awareness and Preferred Mode of Getting Information on First Aid Management of Avulsed Permanent Teeth: Survey of Nigerian Mothers

ABSTRACT Objective: To determine the awareness and sources of information on first aid management of avulsed permanent teeth in a group of South-western Nigerian mothers. Material and Methods: An 18-item interviewer-administered questionnaire was used to survey 385 mothers attending the antenatal and immunization clinics on their perception towards dental avulsion, its management, sources, and preferred mode of receiving information on first aid. The effect of all significant factors was inferred at p<0.05. Results: Mothers who had previous information on the first aid management of dental avulsion had significantly higher knowledge (p=0.000). Majority (80.8%) of the mothers did not know that an avulsed permanent tooth could be replanted, though mothers whose children had not experienced dental trauma had significantly higher knowledge (p=0.003). The knowledge of first aid management of avulsed permanent tooth was low, regardless of age, education and employment status of the respondents. Conclusion: There was low knowledge among mothers regarding the first aid measures in the management of avulsed permanent teeth. Their main preference for receiving information was through social media and television. There is a need to increase oral health educational campaigns targeted towards mothers.

Multidisciplinary conservative management of dental fracture in young patient: case report

The management of fractured permanent teeth due to dental trauma in young patients is a challenge that requires an efficient approach. Objective: Describe a conservative and multidisciplinary treatment of a case of dental trauma in a 13 years-old boy. Case report: At clinical examination was verified enamel and dentin fracture in the left upper central incisor and a fracture with pulp exposure in the right upper lateral incisor, with subgingival extension of its margin at lingual surface, and no swelling or tooth displacement was observed. At radiographic evaluation, no pulp or periradicular disturbances were verified. It was proposed the surgical lengthening of the clinical crown of the right upper lateral incisor for later performing endodontic treatment. It was decided to make direct composite resin restorations in both fractured teeth, instead of doing a prosthetic treatment in the affected lateral incisor, such as the placement of a full ceramic crown, in an attempt to perform a less invasive treatment, mainly due to the age of the patient. At a two years follow-up visit was observed the maintenance of the health of periapical tissues and the absence of clinical alterations. Conclusion: The restorations were kept in good conditions and aesthetics was considered satisfactory by professionals, patient and parents.

Introdução: O manejo de dentes permanentes fraturados por traumatismo dentário em pacientes jovens é desafiador e requer uma abordagem eficiente. Objetivo: Descrever o tratamento conservador e multidisciplinar em um caso de traumatismo dentário de um menino de 13 anos de idade. Relato do caso: Ao exame clínico foi verificada uma fratura de esmalte e dentina no incisivo central superior esquerdo e uma fratura complicada no incisivo lateral superior direito, com extensão subgengival da margem na face palatina, e não foram observados edema ou deslocamento dentário. Ao exame radiográfico, não foram verificadas alterações pulpares ou perirradiculares. Foi proposta realização de aumento da coroa clínica do incisivo lateral superior direito para posterior realização do tratamento endodôntico. Para os dois dentes traumatizados foi proposta a realização de restauração direta com resina composta, proporcionando um tratamento menos invasivo ao incisivo lateral superior direito, ao invés de submetê-lo a um tratamento protético, como a colocação de uma coroa total cerâmica, principalmente devido à pouca idade do paciente. Na visita de dois anos de acompanhamento, observou-se a manutenção da saúde dos tecidos periapicais e ausência de alterações clínicas. Conclusão: As restaurações se mantiveram em boas condições e a estética foi considerada satisfatória pelos profissionais, paciente e pais.

Influence of Vestibular Bevel on the Success of Traumatized Teeth Restorations: Single-Blind Randomized Controlled Trial - Preliminary Results with 6-Months Follow-Up

Abstract Objective: To evaluate the influence of cavosurface vestibular bevel (CSVB) application on the clinical success (CS) of class IV restorations of traumatized permanent teeth, the influence of the number of fracture angles and dental trauma recurrence (DTR) on the restorations retention rate (RRR) and incidence of pulp necrosis (PN). Material and Methods: Fifty-seven children and adolescents with enamel and dentin fractures requiring C-IV restorations were randomly allocated in groups with CSVB and without CSVB. The primary outcomes were the CS of restorations, evaluated using modified USPHS criteria, and the incidence of PN after a 6-months follow-up. As secondary outcomes, the influence of the number of fractured angles and the DTR on the RRR and on the incidence of PN were evaluated (p>0.05). Results: Of 57 children and adolescents, 74 teeth were restored, and 71 completed the six-month follow-up analysis. Teeth restored with and without CSVB displayed similar CS as well as the same incidence of PN (p>0.05). The number of fractured angles did not influence the RRR and DTR was not associated with PN (p>0.05). DTR was associated with a lower RRR (p<0.001). Conclusion: Cavosurface vestibular bevel did not influence the clinical success of Class IV restorations or incidence of PN after 6-months follow-up. DTR did not influence the incidence of pulp necrosis, but did negatively influence the restorations retention rate. The number of fracture angles did not influenced in the restorations retention rate.

Aesthetic recovery of the smile using a simple and effective application of prepolymerized composite veneers

Introduction: The prefabricated composite resin veneers are prepolymerized laminates of composite that appeared in the market to simplify the restorative procedure, reducing working time. They are extremely thin veneers fabricated in several sizes, which allows performing restorations with high aesthetic standard in anterior teeth using a minimally invasive technique. Objectives: This study aimed to show the use of prefabricated resin veneers in the re-anatomization and recovery of dental aesthetics of a young patient with history of fracture and darkening of anterior teeth after aesthetic periodontal surgery. Case report: The patient attended the clinic with a smile complaint and the clinical examination showed tooth 11 with cervical fracture, tooth 21 with color change and caries infiltration, and tooth 22 with inclination of the distal surface toward the palatal region. As treatment, was opted for the use of prefabricated composite resin veneers. Conclusion: The aesthetic results of this case were highly satisfactory, especially when compared with clinical time, cost, and the laboratory work of ceramic veneers, showing the quality and advantages of this material.

Introdução: As facetas pré-fabricadas de resina composta são laminados prépolimerizados de compósito que surgiram no mercado para simplificar o procedimento restaurador, reduzindo o tempo de trabalho. São facetas extremamente finas, fabricadas em diversos tamanhos, com as quais é possível realizar restaurações com alto padrão estético em dentes anteriores através de uma técnica minimamente invasiva. Objetivo: Esse trabalho teve como objetivo demonstrar o uso de facetas pré-fabricadas de resina na reanatomização e recuperação da estética dentária de um paciente jovem com histórico de fratura e escurecimento dos dentes anteriores, após cirurgia estética periodontal. Relato de caso: Paciente compareceu à clínica com queixa do sorriso e ao exame clínico, observou-se dente 11 com fratura cervical, dente 21 com alteração de cor e infiltração por cárie e dente 22 com inclinação da face distal para palatina. Como tratamento, foi optado pela utilização das facetas pré-fabricadas de resina composta. Conclusão: Os resultados estéticos deste caso foram altamente satisfatórios, principalmente quando comparados ao tempo clínico, custo e trabalho laboratorial de facetas de cerâmica, mostrando a qualidade e as vantagens desse material.

Resistência à fratura de dentes tratados endodonticamente reforçados com pinos customizados de fibra de vidro e carbono / Fracture resistance of endodontically treated teeth reinforced with customized glass and carbon fiber posts

Objetivo: o objetivo do presente estudo foi comparar a resistência à fratura de quatro tipos de pinos intrarradiculares pré-fabricados: fibra de vidro, fibra de vidro customizado com resina composta, fibra de carbono e fibra de carbono customizado com resina, em dentes bovinos. Métodos: foram utilizados 60 dentes bovinos unirradiculares, que receberam tratamento endodôntico e foram divididos nos seguintes grupos: FV = pino de fibra de vidro; FVP = pino de fibra de vidro customizado; FC = pino de fibra de carbono; FCP = pino de fibra de carbono customizado; e Controle = restauração coronária com resina composta. Os dentes foram inseridos em blocos de resina acrílica, a 2 mm da junção amelocementária, simulando a interface dente-osso. Os espécimes foram submetidos ao teste de resistência à fratura em máquina de ensaio universal, sob uma carga de 0,5mm/min, até a fratura do corpo de prova. Os valores obtidos foram submetidos ao teste ANOVA, com pós-teste de Tukey. Foi realizada, também, uma análise dos padrões de fratura, por meio do teste Kruskal- -Wallis. Resultados: o grupo FCP mostrou os maiores valores de resistência à fratura, seguido pelos grupos FV, FVP e FC. O grupo controle mostrou menor resistência do que os demais, que receberam pinos intrarradiculares. Os pinos de FVP apresentaram o maior número de fraturas reparáveis, em contraste ao controle, no qual houve o maior número de fraturas desfavoráveis. Conclusão: o uso de pinos customizados reduziu a incidência de fraturas catastróficas. A ausência de pino intrarradicular ocasionou a maior incidência de fraturas irreparáveis. (AU)

Objective: The aim of this study was to compare the fracture resistance of four types of prefabricated intraradicular posts - glass fiber, glass fiber customized by composite resin, carbon fiber, and customized carbon fiber - on bovine teeth. Methods: Sixty bovine teeth were submitted to endodontic treatment and divided into the following groups: GF - glass fiber post; CGF - customized glass fiber post; CF - carbon fiber post; CCF - customized carbon fiber post; control - composite resin restoration. The teeth were embedded in acrylic resin blocks at 2 mm from the cement-enamel junction, simulating the teeth-bone interface. The specimens were submitted to a fracture resistance test in a universal test machine under a 0.5 mm/min load until the fracture of the specimen. The values obtained were submitted to ANOVA and Tukey tests. The analysis of the fracture patterns was performed by the Kruskal-Wallis test. Results: The CCF group presented the highest values of fracture resistance, followed by GF, CGF, and CF posts. The control group offered less resistance than the other groups that received intraradicular posts. The CGF presented the highest number of favorable fractures, in contrast to the control group, which presented the highest number of unfavorable fractures. Conclusion: The use of customized posts reduced the incidence of catastrophic fractures. The lack of intracanal posts led to a higher incidence of irreparable fractures (AU).

Efeito do hipoclorito de sódio e do hidróxido de cálcio na resistência da dentina radicular à fratura / Effect of sodium hypochlorite and calcium hydroxide on fracture resistance of root dentin

Objetivo: o objetivo desse estudo foi avaliar a influência de diferentes concentrações da solução de hipoclorito de sódio (NaOCl) e da pasta de hidróxido de cálcio [Ca(OH)2] sobre a resistência da dentina radicular durante o tratamento endodôntico. Métodos: oitenta raízes de incisivos inferiores bovinos foram distribuídas aleatoriamente em oito grupos: C = Controle (sem intervenção); SSF = solução salina fisiológica; NaOCl 1%; NaOCl 5%; SSF/EDTA; SSF/EDTA/Ca(OH)2; NaOCl 1%/EDTA/Ca(OH)2; e NaOCl 5%/EDTA/Ca(OH)2. Em todos os grupos, os canais radiculares foram preparados com limas tipo K manuais usando a técnica coroa-ápice, exceto no grupo controle. A solução irrigadora de cada grupo foi mantida no canal por 2 h, sendo substituída a cada 15 min. O EDTA foi aplicado durante 3 min nos grupos correspondentes. O Ca(OH)2 foi mantido nos canais radiculares durante 30 dias. Os espécimes foram submetidos a teste de resistência à compressão até a fratura, em uma máquina de ensaios universal EMIC. Os dados foram submetidos à análise de variância. O nível de significância foi estabelecido em alfa = 0,05. Resultados: não foi encontrada diferença estatisticamente significativa entre os grupos experimentais (p > 0,05). Conclusões: o uso de NaOCl por 2h e Ca(OH)2 por 30 dias não influenciou a resistência da dentina radicular. (AU)

Objective: The aim of this study was to assess the influence of different concentrations of sodium hypochlorite (NaOCl) solution and of calcium hydroxide [Ca(OH)2] paste on the strength of root dentin during endodontic treatment. Methods: Eighty roots of bovine mandibular incisors were randomly assigned to eight groups: C- Control (no intervention); PS- Physiological saline; 1% NaOCl; 5% NaOCl; PS/EDTA; PS/EDTA/Ca(OH)2; 1% NaOCl/EDTA/Ca(OH)2; and 5% NaOCl/EDTA/ Ca(OH)2. All groups were prepared with hand K files using the crown-down technique, except for the control group. The irrigating solution in each group was kept in the canal for 2 h, being replaced every 15 min. EDTA was applied for 3 min in the corresponding groups. Ca(OH)2 was kept in the root canals for 30 days. The specimens were subjected to compressive strength testing until fracture in an EMIC universal testing machine. The data were subjected to analysis of variance. The significance level was set as alpha = 0.05. Results: No statistically significant difference was found across the experimental groups (P>0.05). Conclusions: The use of NaOCl for 2h and Ca(OH)2 for 30days did not influence the strength of root dentin (AU).

Fracture strength of teeth with access cavity preparation with operating microscope or on buccal surfaces / Resistência à fratura de dentes submetidos a cavidade de acesso endodôntico com microscópio operatório ou nas faces vestibulares

Objective: The present study assessed the fracture strength of teeth subjected to endodontic access cavity preparation on buccal surfaces, or with the aid of operating microscopy when compared to the conventional technique. Material and methods: Sixty mandibular incisors were split into four groups (n=15): conventional access cavity preparation (CCP); conservative (C); buccal surface (BS); and control. The canals were prepared and filled and the cavities were restored. A static compressive strength test was conducted until crown fracture. The force data were compiled and assessed statistically. Kolmogorov-Smirnov and ShapiroWilk tests were performed to assess normality, Levene's test to assess variance homogeneity, the one-way ANOVA to compare fracture strength in the assessed groups. Tukey's HSD test was used to determine whether the differences in the means were significant between the groups. Results: The experimental groups did not show any statistically significant differences in mean fracture strength (CCP = 585.65 N±107.64 N)(BS = 530.52 N±129.35 N) (C = 517.83 N±114.68 N). Conclusion: Therefore, the selection of surface or size of access cavity proposed did not influence the fracture strength of mandibular incisors when compared to conventional cavity preparation (AU)

Objetivo: O presente estudo avaliou a resistência à fratura compressiva de dentes submetidos as cavidades de acesso endodôntico nas faces vestibulares, ou com o auxílio de microscópio operatório quando comparados à técnica convencional. Material e métodos: Sessenta incisivos inferiores foram divididos em quarto grupos (n=15): cavidade de acesso convencional (CAC); conservadora (C); na face vestibular (FV); e controle. Os canais foram preparados e obturados, e as cavidades restauradas. O teste estático de resistência compressiva foi procedido até a fratura coronária. Os dados de força foram compilados e analisados estatisticamente. Os testes de KolmogorovSmirnov e Shapiro-Wilk foram realizados com o intuito de avaliar a normalidade. O teste de Levene para verificar a homogeneidade de variâncias. O teste de análise de variância a um critério (ANOVA) para comparar a resistência à fratura entre os grupos. O teste de Tukey HSD foi realizado para determinar se as diferenças entre as médias dos grupos apresentava significância. Resultados: Os grupos experimentais não apresentaram diferenças estatisticamente significantes com relação a média de resistência à fratura. (CAC = 585.65 N±107.64 N)(FV = 530.52 N±129.35 N) (C = 517.83 N±114.68 N). Conclusão: Portanto, a variação da face ou do tamanho da cavidade de acesso endodôntico não exerceram influência na resistência à fratura de incisivos inferiores quando comparados a tradicional cavidade de acesso endodôntico. (AU)

Assessment of a conservative approach for restoration of extensively destroyed posterior teeth

Abstract Extensive restorations in posterior teeth always bring doubts to the clinicians regarding the best protocol, mainly when structures of reinforcement were lost. Objective This study aimed to evaluate the effect of beveling on the fracture resistance and pattern of class II (MOD) restored teeth. Methodology Ninety human premolars were randomly assigned into 9 groups: CTR (control/sound); NC (cavity preparation, non-restored); RU (restored, unbeveled); RTB (restored, entire angle beveling); RPB (restored, partial/occlusal beveling); EC (endodontic access/EA, non-restored); EU (EA, unbeveled); ETB (EA, entire angle beveling); EPB (EA, partial/occlusal beveling). Teeth were restored with Esthet X resin composite and stored in distilled water for 24 h before the inclusion in PVC cylinders. The axial loading tests were performed with 500 kgF at 0.5 mm/min crosshead speed until fracture of the specimens. Fracture resistance and pattern were accessed and data were analyzed using one-way ANOVA and Tukey's HSD test (α=0.05). Results Mean (±SD) failure loads ranged from 136.56 (11.62) to 174.04 (43.5) kgF in the groups tested without endodontic access. For endodontically accessed teeth, fracture resistance ranged from 95.54 (13.05) to 126.51 (19.88) kgF. Beveling of the cavosurface angle promoted the highest fracture resistance values (p<0.05) and prevented catastrophic fractures. Conclusions Cavosurface angle beveling is capable of improving fracture resistance and pattern for both endodonticaly accessed and non-accessed teeth.

Reabilitação em dentes anteriores com pinos de fibra de vidro e coroas metal free: relato de caso / Rehabilitation on previous teeth with glass fiber pins and metal free crowns: case report

Objetivo: descrever uma reabilitação em incisivos superiores por meio da associação de coroas totais de cerâmica e retentor intrarradicular de fibra de vidro. Caso clínico: paciente P. C. G., gênero masculino, de 49 anos de idade, leucoderma, insatisfeito com a estética dos dentes anteriores devido a traumatismo dentário e fraturas recorrentes das restaurações. Após a realização de anamnese, exames clínico e radiográfico, contataram-se restaurações de resina composta insatisfatórias nos dentes anteriores, grandes diastemas entre os dentes e leve inflamação gengival. Para o plano de tratamento, optou-se por realização do tratamento endodôntico dos elementos 12 e 22, pino de fibra de vidro no dente 21, e coroas totais de dissilicato de lítio em todos os incisivos superiores. Considerações finais: com a finalização do tratamento e o retorno do paciente à clínica após seis meses, pode-se observar um tecido gengival sadio e o paciente muito satisfeito com os resultados obtidos. (AU)

Objective: to describe a rehabilitation in upper incisors through the association of total ceramic crowns and intra-radicular fiberglass retainer. Clinical case: patient P. C. G. male sex, 49 years old, leucoderma, dissatisfied with the aesthetics of the anterior teeth due to dental traumatism and recurrent fractures of the restorations. After anamnesis, clinical and radiographic examination, unsatisfactory composite resin restorations on anterior teeth, large diastema between teeth and mild gingival inflammation were contacted. For the treatment plan, we chose to perform endodontic treatment of elements 12 and 22, glass fiber pin on tooth 21, and total crowns of lithium disilicate on all upper incisors. Final considerations: with the completion of the treatment and return of the patient to the clinic after six months, a healthy gingival tissue can be observed and the patient very satisfied with the results obtained. (AU)

Efeito do hipoclorito de cálcio na resistência de adesão do cimento obturador AH Plus à dentina / Effect of calcium hypochlorite on the bond strength of the AH Plus sealer to dentin

Objetivo: avaliar o efeito do uso de hipoclorito de cálcio (Ca(OCl)2) como irrigante na resistência de adesão do cimento AH Plus (De Trey-Dentsply, Konstanz, Alemanha) à dentina pelo teste de micro push-out. Materiais e método: trinta e três dentes humanos monorradiculares foram seccionados transversalmente na junção amelocementária e divididos em três grupos: hipoclorito de sódio (NaOCl) 2,5%, hipoclorito de cálcio 2,5% e soro fisiológico. Os canais foram preparados, irrigados ao final com EDTA 17% e obturados com cones de guta percha e cimento AH Plus. Após armazenagem por 7 dias, em 100% de umidade e a 37°C, os dentes foram seccionados transversalmente ao longo do eixo da raiz. Foram obtidas três fatias de cada dente (n=33), que foram submetidas ao ensaio de push-out. O tipo de falha foi analisado por fractografia e classificado em falha adesiva, coesiva ou mista. Os valores de resistência de união foram analisados pelo teste de Kruskal-Wallis, com nível de significância de 95%. Resultados: o grupo Ca(OCl)2 2,5% apresentou a menor média de resistência de adesão, diferindo estatisticamente do NaOCl e do soro fisiológico (p<0,05). Não houve diferença estatística entre os grupos irrigados com soro e NaOCl (p>0,05). Conclusões: a falha predominante em todos os grupos foi a do tipo adesiva. O Ca(OCl)2 2,5% teve um efeito negativo sobre a força de adesão do AH Plus à dentina radicular quando comparado ao NaOCl 2,5%. (AU)

Objective: to evaluate the effect of calcium hypochlorite (Ca(OCl)2) as an irrigant on the bond strength of the AH Plus sealer (De Trey-Dentsply, Konstanz, Germany) to dentin, using the micro push-out test. Materials and method: thirty-three single-rooted human teeth were cross-sectioned on the cementoenamel junction and divided into three groups: 2.5% sodium hypochlorite (Na- OCl), 2.5% calcium hypochlorite, and saline solution. The canals were prepared, irrigated with 17% EDTA at the end, and filled with gutta-percha cones and AH Plus sealer. After being stored for seven days at 100% humidity and 37ºC, the teeth were cross-sectioned along the root axis. Three slices of each tooth (n=33) were obtained and subjected to the push-out test. Failure mode was analyzed by fractography and classified as adhesive, cohesive, or mixed. Bond strength values were analyzed by the Kruskall-Wallis test at 95% significance level. Results: the 2.5% Ca(OCl)2 group showed the lowest bond strength mean, differing statistically from 2.5% NaOCl and saline solution (p<0.05). There was no statistical difference between the groups irrigated with saline solution and NaOCl (p>0.05). Conclusion: the adhesive failure was predominant in all groups. The 2.5% Ca(OCl)2 had a negative effect on the bond strength of AH Plus to the root dentin when compared to 2.5% NaOCl. (AU)

Reconstrução alveolar imediata às exodontias de molares sem uso de barreiras: apresentação de um protocolo / Immediate alveolar reconstruction for molar extraction sites without guided-bone regeneration barrier membranes: a proposed protocol

Este artigo apresenta uma metodologia para tratamento de defeitos alveolares com ausência de uma ou duas paredes ósseas, em regiões de molares, sem o uso de barreiras de Regeneração Óssea Guiada (ROG). A metodologia e seus fundamentos são discutidos e um caso clínico é detalhado para melhor elucidação.

This article presents a special protocol for treatment of alveolar defects in molar regions where one ore two bone walls are absent without using Guided Bone Regeneration (GBR). Its methodological aspects and basic tenets are discussed in addition to a detailed clinica case for better comprehension of this interesting protocol.

Comparison of Digital Diagnostic Value and Cone Beam Computed Tomography (CBCT) in Determining Vertical Root Fracture in Single- Root Teeth

Objective: To compare the accuracy of digital radiography and CBCT for the diagnosis of vertical root fractures in single root teeth. Material and Methods: For this descriptive-analytic study, 50 non-fractured, single-root teeth were selected. The teeth were randomly divided into a control and an experimental group (25 teeth in each group). The teeth in the control group did not have vertical root fractures. In the test group, after preparing the access cavity, the root canal was cleared and loosened up to No. 80 file, then a vertical root fracture was created by one of the K-Reamers Nos. 90- 130.The images were prepared by CBCT radiography in axial and cross-sectional slices and in digital radiography with PSP sensors at mesial, distal, and parallel angles. The Chi-square test was used to express the correlation of variables. Results: In the diagnosis of vertical root fractures, the sensitivity of CBCT in the axial section was 32% and in the cross-sectional slice it was 20%, whereas the specificity in both the sections was 100%. The sensitivity of the digital radiography in detecting vertical root fractures for parallel, mesial, and distal angles was 38%, 16%, and 24%, respectively. Conclusion: According to this study, the sensitivity, specificity, and accuracy of digital radiography and CBCT were not significantly different.

Effects of intracanal medicaments and the remaining cavity wall on fracture strength of endodontically treated molars / Efeitos dos medicamentos intracanais e do muro de cavidade remanescente na força de fratura dos molares endodonticamente tratados

Objective: The aim of this study was to investigate the effects of the short-term intracanal application of two medicaments on the fracture strength of root-filled molar teeth with different levels of tooth structure loss. Material and Methods: Standard access cavities of totally 84 intact maxillary molar teeth were prepared in 72 teeth and were divided into 3 main groups. Standard access cavities were kept in the first group, while mesio-occlusal-distal cavities (MOD) were prepared in the second and third groups. One-half of the palatinal walls were removed in the third group. Twelve sound teeth were used in the fourth group as control. Each group was then assigned into two subgroups according to the medicament used (n=12): 2% chlorhexidine gel and calcium hydroxide. Samples were stored at 37°C and 100% humidity for 1 week. Then the teeth were inserted into a universal testing machine and vertically loaded (5 mm/min) from the occlusal surface. The data was recorded in Newtons and statistically evaluated using a Univariate ANOVA and a Tukey as post hoc test. Results: A significant difference was found among the test groups (p <0.01). No significant difference was found according to the medicament used (p>0.05), however the number of remaining walls significantly affected the fracture strength (p <0.01). The first group with access cavity showed mostly repairable fractures (60%­80%) whereas the others showed mostly nonrepairable fracture patterns s (60%­90%). Conclusion: In conclusion, the fracture strength of endodontically treated teeth is related to the structure loss rather than the intracanal medicament used. (AU)

Objetivo: O objetivo deste estudo foi investigar os efeitos da aplicação intracanal de curto prazo de dois medicamentos sobre a resistência à fratura de dentes molares preenchidos com raízes com diferentes níveis de perda de estrutura dentária. Material e Métodos: cavidades de acesso padrão de totalmente 84 dentes molar maxilares intactos foram preparadas em 72, dentes e foram divididas em 3 grupos principais. As cavidades de acesso padrão foram mantidas no primeiro grupo, enquanto as cavidades mesooclusais-distal (MOD) foram preparadas no segundo e terceiro grupos. A metade das paredes palatinas foi removida no terceiro grupo. Doze dentes de som foram utilizados no quarto grupo como controle. Cada grupo foi então atribuído em dois subgrupos de acordo com o medicamento utilizado (n = 12): 2% de gel de clorhexidina e hidróxido de cálcio. As amostras foram armazenadas a 37 ° C e 100% de umidade por 1 semana. Em seguida, os dentes foram inseridos em uma máquina de teste universal e carregados verticalmente (5 mm / min) da superfície oclusal. Os dados foram registrados em Newtons e avaliados estatisticamente usando uma ANOVA Univariada e um Tukey como teste post hoc. Resultados: uma diferença significativa foi encontrada entre os grupos de teste (p <0,01), no entanto, o número de paredes restantes afetou significativamente a resistência à fratura (p <0,01). O primeiro grupo com cavidade de acesso apresentou fracturas principalmente reparáveis (60% -80%), enquanto as demais apresentaram padrões de fratura não reparáveis (60% -90%). Conclusão: Em conclusão, a resistência à fratura dos dentes tratados endodonticamente está relacionada à perda da estrutura em vez do medicamento intracanal utilizado.(AU)

Influence of remaining coronal thickness and height on biomechanical behavior of endodontically treated teeth: survival rates, load to fracture and finite element analysis

Abstract Objective To evaluate the effect of restorative strategy (fiber post vs cast post and core), coronal height (0 mm vs 2 mm) and thickness (higher than 1 mm vs lower than 1 mm) on survival rate, fracture resistance and stress distribution. Material and Methods Seventy-two bovine teeth were cleaned and allocated in six groups (n = 12). Twenty-four teeth were sectioned at 13 mm length (no remaining coronal structure) and forty-eight were sectioned at 15 mm (2 mm remaining coronal structure). Half of the forty-eight had remaining coronal thickness lower than 1 mm and the other half had thickness higher than 1 mm. All root canals were prepared at 10 mm (luting length), fiber posts were cemented in thirty-six specimens and cast post and core in other thirty-six. All teeth were restored with metallic crowns. Specimens were submitted to 1.5 million cycles (100 N, 45°, 10 Hz at 2 mm below incisal edge) and evaluated at each 500,000 cycles to detect failures. Specimens that survived were submitted to load to fracture test. Bidimensional (Rhinoceros® 4.0) models were obteined survival data submitted to Kaplan-Meier (α=0.05) analysis and load to fracture values submitted to ANOVA and Tukey tests (α=0.05). Results Groups without remaining coronal structure showed survival rates lower than other groups (p=0.001). ANOVA showed higher values of load to fracture for groups with coronal thickness higher than 1 mm (p=0.0043). Finite element analysis showed better stress distribution in groups with remaining coronal structure and restored with fiber post. Conclusion Specimens without remaining coronal structure have lower survival rates. Specimens with remaining structure lower than 1 mm and without coronal structure support the same load to fracture value independently of the restorative strategy.

Effect of cavity preparation design and ceramic type on the stress distribution, strain and fracture resistance of CAD/CAM onlays in molars

Abstract Objective This study aimed to evaluate the effect of the cavity preparation and ceramic type on the stress distribution, tooth strain, fracture resistance and fracture mode of human molar teeth restored with onlays. Material and Methods Forty-eight molars were divided into four groups (n=12) with assorted combinations of two study factors: BL- conventional onlay preparation with boxes made from leucite ceramic (IPS-Empress CAD, Ivoclar Vivadent); NBL- conservative onlay preparation without boxes made from leucite ceramic; BD- conventional onlay preparation with boxes made from lithium disilicate glass ceramic (IPS e.max CAD, Ivoclar Vivadent); NBL- conservative onlay preparation with boxes made from lithium disilicate glass ceramic cuspal deformation (µS) was measured at 100 N and at maximum fracture load using strain gauge. Fracture resistance (N) was measured using a compression test, and the fracture mode was recorded. Finite element analysis was used to evaluate the stress distribution by modified von Mises stress criteria. The tooth strain and fracture resistance data were analyzed using the Tukey test and two-way ANOVA, and the fracture mode was analyzed by the chi-square test (α=0.05). Results The leucite ceramic resulted in higher tooth deformation at 100 N and lower tooth deformation at the maximum fracture load than the lithium disilicate ceramic (P<0.001). The lithium disilicate ceramic exhibited higher fracture resistance than the leucite ceramic (P<0.001). The conservative onlay resulted in higher fracture strength for lithium disilicate ceramic. Finite element analysis results showed the conventional cavity preparation resulted in higher stress concentration in the ceramic restoration and remaining tooth than the conservative onlay preparation. The conservative onlays exhibited increased fracture resistance, reduced stress concentration and more favorable fracture modes. Conclusion Molars restored with lithium disilicate CAD-CAM ceramic onlays exhibited higher fracture resistance than molars restored with leucite CAD-CAM ceramic onlays.