Treatment of a severely compromised endodontically treated tooth with a 2-piece premanufactured glass-fiber post: A clinical report.

A 2-piece premanufactured glass-fiber post-and-core for a child with a severely compromised endodontically treated tooth to restore dental form, function, and esthetics, is described. A shorter chair time than for the conventional options was needed, and the post provided an adequate biomechanical response with a reduced intracanal cement thickness.

Optimization of Results for Cracked Teeth Using CAD-CAM System: A Case Series.

Different restorative techniques have been proposed for the treatment of posterior teeth affected by cracked tooth syndrome (CTS). However, the literature is scarce in protocols of how to solve CTS using ceramic restorations made by computer aided design-computer aided manufacturing (CAD-CAM) system. CAD-CAM provides a fast and efficient restorative treatment usually in a single visit, reducing the risk of contamination and micro-infiltration of the cracked line. The objective of this work was to describe 3 clinical cases of cracked teeth, which presented vertical fracture lines in different directions and extension through the pulp, restored by CAD-CAM system, with 5-year follow-up. Patients with short-term spontaneous masticatory pain, cold sensibility and restored teeth without cuspal coverage were selected. Digital radiographs (DR) were taken to confirm the pulp and periapical status. Periodontal probing depth, sensitivity, percussion, and occlusion tests were performed. The fracture lines with their direction and extension were identified under dental optical microscope (DOM). The treatment plan was performed in two stages: immediate treatment to stabilize the tooth and minimize pain, and final restorative treatment by CAD-CAM system to stabilize the crack. Patients were between the ages of 37 and 45 years. Most of the studied teeth presented extensive restorations without cuspal coverage. The presence of occlusal interference, in lateral movement, was a constant finding. Endodontic treatment was performed in cases of irreversible pulpitis or pulpal necrosis. In all three cases, cavity preparation was performed for full coverage restorations, as the fracture lines extended in several directions, requiring a re-enforcement of the cervical region of the teeth in question. The survival rate of the reported cases was 100% with 5-year clinical and radiographic follow-up, suggesting that CAD-CAM system may be a promising alternative treatment in the management of CTS, improving tooth longevity.

Case Reports in Maxillary Posterior Teeth by Guided Endodontic Access.

The localization of partial or completed root canal obliteration is a challenging task in endodontic practice. Recently, guided endodontics has become an alternative solution for those cases. Although this technique has already been used clinically in managing anterior teeth, in this report, we describe 3 complex clinical scenarios of calcified root canals of 1 molar and 2 premolars using guided endodontics. The clinical cases reported here show that technological evolutions should make guided endodontic procedures more widespread because their execution is relatively fast and safe even in the case of the upper molar. Additionally, 12-month clinical follow-up visits showed the effectiveness of the guided endodontic procedures.

Three-dimensional endodontic guide for adhesive fiber post removal: A dental technique.

This dental technique describes a protocol for adhesive fiber post removal using a prototyped endodontic guide. The removal of an adhesive fiber post is an important step for endodontic retreatment and the resolution of prosthetic problems. Computer-aided design and computer-aided manufacturing (CAD-CAM) technology was used to generate guides with prototyping and is a useful tool for fiber post removal.

Mini fiberglass post for composite resin restorations: A clinical report.

Threaded metal pins have been used to create additional retention for large composite resin restorations. However, their dark appearance may compromise esthetic outcome. The use of small fiberglass posts has been advocated as an alternative. This clinical report describes a mini fiberglass post (MFP) used to provide additional retention in a fractured anterior tooth that received a composite resin restoration. The MFP represents a promising option for creating additional retention for large composite resin restorations.

Retention strength of cobalt-chromium vs nickel-chromium titanium vs CP titanium in a cast framework association of removable partial overdenture.

AIM: There is little information considering the framework association between cast clasps and attachments. The aim of this study was to evaluate the retention strength of frameworks match circumferential clasps and extra resilient attachment cast in three different alloys (cobalt-chromium, nickel-chromium titanium and commercially pure titanium), using two undercut (0.25 and 0.75 mm) and considering different period of time (0, 1/2, 1, 2, 3, 4 and 5 years). METHODS: Using two metallic matrices, representing a partially edentulous mandibular right hemiarch with the first molar crown, canine root and without premolars, 60 frameworks were fabricated. Three groups (n = 20) of each metal were cast and each group was divided into two subgroups (n = 10), corresponding the molar undercut of 0.25 mm and 0.75 mm. The nylon male was positioned at the matrix and attached to the acrylic resin of the prosthetic base. The samples were subjected to an insertion and removal test under artificial saliva environment. RESULTS: The data were analyzed and compared with ANOVAs and Tukey's test at 95% of probability. The groups cast in cobaltchromium and nickel-chromium-titanium had the highest mean retention strength (5.58 N and 6.36 N respectively) without significant difference between them, but statistically different from the group cast in commercially pure titanium, which had the lowest mean retention strength in all the periods (3.46 N). The association frameworks using nickel-chromium- titanium and cobalt-chromium could be used with 0.25 mm and 0.75 mm of undercut, but the titanium samples seems to decrease the retention strength, mainly in the 0.75 mm undercut. The circumferential clasps cast in commercially pure titanium used in 0.75 mm undercuts have a potential risk of fractures, especially after the 2nd year of use. CONCLUSION: This in vitro study showed that the framework association between cast clasp and an extra resilient attachment are suitable to the three metals evaluated, but strongly suggest extra care with commercially pure titanium in undercut of 0.75 mm. CLINICAL SIGNIFICANCE: Frameworks fabricated in Cp Ti tend to decrease in retentive strength over time and have a potential risk of fracture in less than 0.75 mm of undercut.

Bond strength of resin cements to Co-Cr and Ni-Cr metal alloys using adhesive primers.

PURPOSE: The aim of this study was to evaluate the effectiveness of adhesive primers (APs) applied to Co-Cr and Ni-Cr metal alloys on the bond strength of resin cements to alloys. MATERIALS AND METHODS: Eight cementing systems were evaluated, consisting of four resin cements (Bistite II DC, LinkMax, Panavia F 2.0, RelyX Unicem) with or without their respective APs (Metaltite, Metal Primer II, Alloy Primer, Ceramic Primer). The two types of dental alloys (Co-Cr, Ni-Cr) were cast in plate specimens (10 x 5 x 1 mm(3)) from resin patterns. After casting, the plates were sandblasted with aluminum oxide (100 microm) and randomly divided into eight groups (n = 6). Each surface to be bonded was treated with one of eight cementing systems. Three resin cement cylinders (0.5 mm high, 0.75 mm diameter) were built on each bonded metal alloy surface, using a Tygon tubing mold. After water storage for 24 hours, specimens were subjected to micro-shear testing. Data were statistically analyzed by two-way ANOVA and Tukey's studentized range test. RESULTS: The application of Metal Primer II resulted in a significantly higher bond strength for LinkMax resin cement when applied in both metal alloys. In general, the cementing systems had higher bond strengths in Co-Cr alloy than in Ni-Cr. CONCLUSIONS: The use of AP between alloy metal surfaces and resin cements did not increase the bond strength for most cementing systems evaluated.

Influência da modificação do desenho de infraestruturas cerâmicas e metálicas na vida útil à fadiga e no modo de falha / Influence of modified framework design in all-ceramic and metal-ceramic crowns fatigue life and failure mode

Avaliar a influência da modificação do desenho da infraestrutura na vida útil à fadiga e no modo de falha em coroas metalo-cerâmicas e alumina infiltrada por vidro. Quarenta réplicas de um primeiro molar superior foram produzidas para receber coroas com infraestrutura padrão ou modificada. A infraestrutura modificada consistiu do desenho padrão (0,5 mm de espessura) aumentada por uma cinta lingual, unindo dois postes proximais. A carga (30-300 N) foi aplicada por um endentador metálico (3,18 mm raio) na superfície oclusal, durante 106 ciclos ou até a falha. A cada 125.000 ciclos o teste era interrompido para avaliar os danos. Fraturas catastróficas ou da porcelana de revestimento e a presença da trinca cone interno estendendo-se a infraestrutura foram os critérios utilizados para definir falha. As superfícies fraturadas e as polidas foram analisadas com estereomicroscópio e por microscopia eletrônica de varredura. A distribuição de Weibull foi utilizada para a análise estatística. A vida útil à fadiga da metalo-cerâmica foi significativamente maior que da alumina; contudo, a modificação não alterou este parâmetro nos grupos metálico ou cerâmico. Os grupos metalo-cerâmico apresentaram trincas cone interno sem fraturas da porcelana de revestimento. O grupo alumina com infraestrutura padrão apresentou principalmente fratura da porcelana de revestimento, enquanto que no grupo alumina com infraestrutura modificada se observou cone interno. A vida útil à fadiga não melhorou com a modificação no desenho das infraestruturas. O modo de falha variou de acordo com o material da infraestrutura.

To evaluate the effect of framework design on the fatigue life and failure modes of metal-ceramic and glass-infiltrated alumina. Forty composite resin tooth-replica of a prepared maxillary first molar were produced to receive crowns of a standard or modified framework design. Core design modification consisted of a standard, connecting to proximal struts. R-ratio fatigue loading was delivered with a spherical steel indenter (3.18 mm radius) on the center of the occlusal surface at a 30-300 N load range, until completion of 106 cycles or failure. Fatigue was interrupted every 125.000 cycles for damage evaluation. Catastrophic fracture, chipping within veneering porcelain, or inner cone crack reaching the core-veneer interface were the criteria for failure. Fractured and polished surfaces were characterized under light polarized microscopy followed by scanning electron microscopy. Weibull distribution fit was used for examining differences between groups. The highest fatigue life was observed for metal-ceramic crowns, but no significant differences were observed for groups with or without framework design modification. Failure modes of metal-ceramic comprised inner cone cracks without porcelain fracture. Glass-infiltrated alumina standard crowns presented bulk fracture whereas glass-infiltrated alumina modified crowns failed mainly through veneer. Fatigue life was not improved with framework design modification. Failure modes varied according to core material.

Hertzian contact response of dentin with loading rate and orientation.

OBJECTIVE: To test the hypothesis that dentin Hertzian contact response varies with loading rate and tubule orientation. DESIGN: Sound teeth (n=12) were cut either parallel or perpendicular to the axial direction to expose dentin (n=6 each). The cut specimens were embedded (poly-methyl-methacrylate (PMMA) and divided into two groups: (GL) load applied parallel to dentin tubule direction and (GP) load applied perpendicular to tubule direction. A 1.5mm diameter tungsten-carbide ball was used for Hertzian contact testing with a maximum load of 150 N load and loading rates of 0.1, 1, 100, and 1000 N/s on each specimen. Indented specimens were observed microscopically and photomicrographs acquired. Hertzian contact diameter and modulus were analysed (p<0.05) by one-way ANOVA and Tukey test. RESULTS: There were significant differences (p<0.05) in Hertzian response with respect to loading rate for GL (0.1N/s versus 1000 N/s, 0.1N/s versus 100 N/s, 1N/s versus 1000 N/s, and 1N/s versus 100 N/s), and GP (0.1N/s versus 1000 N/s, 0.1N/s versus 100 N/s, and 1N/s versus 1000 N/s). Contact modulus was higher for GL compared to GP at all loading rates (p<0.05). CONCLUSION: The results suggest that dentin contact modulus is loading rate dependent. Tubule orientation of dentin did not influence contact modulus values (p>0.05).

Effect of 2 percent iodine disinfecting solution on bond strength to dentin

INTRODUCTION: Disinfection of dentin surfaces is desirable so long as it does not interfere with subsequent bonding of adhesive resins. OBJECTIVE: To test the null hypothesis that bond strengths to dentin are not affected by previous application of an iodine disinfecting solution. MATERIALS AND METHODS: Twenty-four extracted non-carious molars were selected. Occlusal enamel was removed producing a flat dentin substrate. Test teeth were all treated with 2 percent Iodine disclosing/disinfecting solution (I2DDS) for 20 sec and rinsed for 20 sec followed by the application of self- or total- etching bonding systems, generating five adhesive groups (n=3): Single Bond; ; Prime & Bond NT; Clearfil SE Bond; Opti-Bond Plus. The control groups (n=3 per adhesive) had no disclosing/disinfectant application prior to adhesive application. A 4-mm thick resin restoration was built up on each tooth for microtensile testing. Statistical analyses between experimental and control groups were performed by student's t-test (alpha= 0.05). RESULTS: In general, experimental groups (previously treated with I2DDS) showed significantly lower bond strength values when compared with their respective controls (p<0.05), except for group Prime &Bond I2 that did not significantly differ from its control (p>0.05). CONCLUSION: Acetone-base adhesive systems seem not to be affected by the application of I2DDS prior to etching and bonding procedures.

INTRODUÇÃO: A desinfecção das superfícies de dentina é desejada desde que não haja interferência na adesão dos agentes adesivos. OBJETIVO: Testar a hipótese nula de que a resistência adesiva não é afetada pela aplicação prévia de uma solução desinfetante de iodo. MATERIAL AND MÉTODO: Vinte e quatro molares hígidos foram selecionados. O esmalte oclusal destes dentes foi removido, e sobre as superfícies planas de dentina expostas foi aplicada da solução desinfetante de Iodo a 2 por cento (I2DDS), que permaneceu sobre a superfície por 20 s e foi lavada por 20 s com água deionizada. Sobre as superfícies desinfetadas foram aplicados um dos seguintes sistemas adesivos (n=3): Single Bond; Prime & Bond NT; Clearfil SE Bond; Opti-Bond Plus. Os grupos controle (n=3) não tiveram a supeficie de dentina tratada com I2DDS antes dos precedimentos adesivos. Em todos os grupos, após hibridização da dentina, foi construída uma "restauração" de resina composta com cerca de 4 mm de espessura. Após 7 dias de armazenagem em água destilada, os dentes foram secionados de modo a originarem espécimes a serem submetidos ao teste de microtração (palitos). Análise estatística para comparação dos dados foi realizada pelo teste t de student (alfa=0,05). RESULTADOS: De forma geral, os grupos experimentais (tratados com I2DDS) apresentraram resistência adesiva significativamente menor do que os respectivos grupos controle (p<0.05), exceção se fez apenas para o grupo P&BI2, que não diferiu significativamente de seu grupo controle P&BC (p>0.05). Assim, a hipótese nula deve ser rejeitada para os adesivos a base de etanol e/ou a base de água, mas aceita para o adesivo a base de acetona. CONCLUSÃO: O uso da solução experimental de iodo previamente à realização dos procedimentos adesivos afetou a efetividade da união à dentina apenas quando do emprego de sistemas adesivos a base de etanol e/ou água.

Effect of 2% iodine disinfecting solution on bond strength to dentin.

INTRODUCTION: Disinfection of dentin surfaces is desirable so long as it does not interfere with subsequent bonding of adhesive resins. OBJECTIVE: To test the null hypothesis that bond strengths to dentin are not affected by previous application of an iodine disinfecting solution. MATERIALS AND METHODS: Twenty-four extracted non-carious molars were selected. Occlusal enamel was removed producing a flat dentin substrate. Test teeth were all treated with 2% Iodine disclosing/disinfecting solution (I(2)DDS) for 20 sec and rinsed for 20 sec followed by the application of self- or total- etching bonding systems, generating five adhesive groups (n=3): Single Bond; Prime & Bond NT; Clearfil SE Bond; Opti-Bond Plus. The control groups (n=3 per adhesive) had no disclosing/disinfectant application prior to adhesive application. A 4-mm thick resin restoration was built up on each tooth for microtensile testing. Statistical analyses between experimental and control groups were performed by student's t-test (alpha= 0.05). RESULTS: In general, experimental groups (previously treated with I(2)DDS) showed significantly lower bond strength values when compared with their respective controls (p<0.05), except for group Prime & Bond I(2) that did not significantly differ from its control (p>0.05). CONCLUSION: Acetone-base adhesive systems seem not to be affected by the application of I(2)DDS prior to etching and bonding procedures.

Avaliação da resistência adesiva da interface de união em diferentes angulações empregando testes de microtração e análise dos elementos finitos / Evaluation of the microtensile bond strenght interface in different angles, testing the null hypothesis

Este estudo avaliou a resistência de união da interface adesiva, utilizando dois sistemas adesivos ("total-etching e self-etching"), testando diferentes ângulos da junção adesiva, com o teste de microtração e análise dos elementos finitos (AEF). Vinte e quatro molares hígidos recém extraídos foram selecionados e tiveram o esmalte oclusal removido perpendicularmente ao longo eixo dos dentes e foram divididos em dois grupos com 12 dentes, empregado-se no grupo 1 o adesivo Single Bond (3M-Espe Co.) e no grupo 2 o adesivo Clearfil SE Bond (Kuraray Co.). Restaurações de resina Z 100 com 4mm de espessura foram confeccionadas após a aplicação dos adesivos. Para realização dos testes de microtração foram obtidos espécimes com ângulos de 0o (controle), 10o, 20o e 30o na interface adesiva. O teste estatístico empregado foi ANOVA a dois critérios e teste de TUKEY. Foi realizada também análise dos elementos finitos, simulando as mesmas condições do teste de microtração. Os resultados mostraram uma diminuição dos valores da resistência adesiva à medida que a inclinação da interface adesiva aumentava sendo estatisticamente significante (p < 0.05) entre 0 e 30 graus de inclinação para o Clearfil SE Bond e entre 0 (controle) e 10, 20 e 30 graus de inclinação para o Single Bond, aceitado parcialmente a hipótese nula. Os resultados obtidos com AEF com a interface de 50 m e 100 m de espessura da camada adesiva mostraram uma tendência semelhante aos resultados obtidos com o teste de microtração