Influence of an iodonium salt on the properties of dual-polymerizing self-adhesive resin cements.

STATEMENT OF PROBLEM: Dual-polymerizing self-adhesive resin cements present mechanical properties that may adversely affect the clinical performance of luted fiber-reinforced posts. PURPOSE: The purpose of this in vitro study was to evaluate the properties of dual-polymerizing self-adhesive resin cements after the addition of an onium salt. MATERIAL AND METHODS: The experimental groups were set according to the molar concentration of diphenyliodonium hexafluorphosphate (DPIHFP) (0.5, 1, and 2 mol%). The resin cements were submitted to a push-out bond strength test and assessed for flexural strength (ISO 4049/2009), degree of conversion (Fourier-transformed infrared spectroscopy), depth of polymerization, swelling coefficient, and degradation in solvent. The data were statistically analyzed by ANOVA, Tukey test, Kruskal-Wallis test, Dunn multiple comparison, and paired Student t test (α=.05). RESULTS: All the RelyX U100 groups with onium salt showed the highest degree of conversion after 24 hours and 7 days (P<.001). However, no statistical difference was found among the BisCem groups (P=.054). The addition of 0.5 mol% DPIHFP increased the push-out bond strength and microhardness of RelyX U100 and promoted less degradation after immersion in solvent. The BisCem control group did not present a statistical difference from the experimental groups in terms of bond strength; the control group and the 0.5 mol% group showed no degradation in solvent. For swelling coefficient and flexural strength, no difference was found between the BisCem groups (P=.067 and P=.173), and the RelyX U100 2 mol% group presented the lower value (P<.001 and P=.048). Depth of polymerization was not statistically different in the experimental groups for either resin cement (P=.999). CONCLUSIONS: The addition of 0.5 mol% DPIHFP improved the physical properties of dual-polymerizing self-adhesive resin cements.

Abordagem periodontal e protética para o fechamento de diastemas ­ relato de caso / Periodontal and prosthetic approach to diastema closure - case report

O diastema é uma das queixas estéticas mais comuns em clínicas odontológicas e caracteriza-se por espaços distintos entre dois dentes, geralmente entre incisivos centrais. Sua solução é variada, o planejamento pode incluir ortodontia, cirurgias periodontais e restaurações diretas ou indiretas. O objetivo do presente trabalho é relatar um caso clínico de cirurgia periodontal prévia ao fechamento de diastemas com facetas de cerâmica. Paciente compareceu à clínica odontológica da Universidade Nilton Lins com queixa de insatisfação com seu sorriso. No exame intraoral, observou-se presença de diastemas entre os dentes anteriores em ambos os arcos. Inicialmente foram realizadas moldagem e montagem em articulador para correta avaliação e planejamento. Após análises de proporcionalidade e harmonia estética dos dentes anteriores foi proposta a realização de cirurgia de aumento de coroa clínica e reanatomização com facetas de cerâmica. Executou-se o procedimento cirúrgico nos dentes 11, 12, 13, 21, 22 e 23 e, após a cicatrização, nova moldagem dupla. Os modelos resultantes foram reproduzidos digitalmente, seguidos da confecção de enceramento de diagnóstico e impressão de modelos em 3D. Realizou-se o teste estético prévio com resina bisacrílica, com a aprovação da paciente, partiu-se para os preparos e nova moldagem do arco superior. A partir do enceramento, as facetas de cerâmica foram confeccionadas e, a seguir, instaladas com cimento resinoso dual. As técnicas empregadas proporcionaram uma harmonização satisfatória do sorriso, devolvendo a autoestima da paciente (AU).

Diastema is one of the most common aesthetic complaints in dental clinics, characterized by distinct spaces between two teeth, usually between central incisors. Its solution is varied and may include orthodontics, periodontal surgeries, and direct or indirect restorations. The aim of this study is to report a case report of periodontal surgery prior to the closure of diastemas with ceramic veneers. Patient attended the dental clinic of Nilton Lins University complaining of dissatisfaction with her smile. In the intraoral examination, diastema was observed between the anterior teeth in both arches. Initially were made molding and assembly in articulator for correct evaluation and planning. After analysis of proportionality and aesthetic harmony of the anterior teeth, it was proposed to perform the periodontal surgery and reanatomization with ceramic veneers. The surgical procedure was performed on teeth 11, 12, 13, 21, 22 and 23 and, after healing, a new double impression. The resulting models were digitally reproduced for diagnostic waxing followed by 3D model printing. The previous aesthetic test was performed with bisacrylic resin, with the patient's approval, the preparation was performed and the upper arch was re-molded. With the diagnostic waxing, the porcelain veneers were made and then installed with dual resin cement. The techniques employed provided a satisfactory harmonization of the smile, restoring the patient's self-esteem (AU).

Influence of delayed pouring on irreversible hydrocolloid properties.

The aim of this study was to evaluate the physical properties of irreversible hydrocolloid materials poured immediately and after different storage periods. Four alginates were tested: Color Change (Cavex); Hydrogum (Zhermack); Hydrogum 5 (Zhermack); and Hydro Print Premium (Coltene). Their physical properties, including the recovery from deformation (n = 3), compressive strength (n = 3), and detail reproduction and gypsum compatibility (n = 3), were analyzed according to ANSI/ADA specification no. 18. Specimens were stored at 23ºC and humidity and were then poured with gypsum immediately and after 1, 2, 3, 4, and 5 days. The data were analyzed by two-way analysis of variance (ANOVA) and Tukey's test at p < 0.05. All of the alginate impression materials tested exhibited detail reproduction and gypsum compatibility at all times. Hydro Print Premium and Hydrogum 5 showed recovery from deformation, as established by ANSI/ADA specification no. 18, after 5 days of storage. As the storage time increased, the compressive strength values also increased. Considering the properties of compounds' recovery from deformation, compressive strength, and detail reproduction and gypsum compatibility, irreversible hydrocolloids should be poured immediately.

Reabilitação bucal com próteses conjugadas ­ relato de caso / Oral rehabilitation with conjugated prosthesis ­ case report

A conjugação entre próteses fixa e removível representa hoje um universo de possibilidades para reabilitações. Nas próteses conjugadas, os encaixes merecem um destaque especial, pois fornecem vantagens nos aspectos biológicos, mecânicos e estéticos. O objetivo do presente trabalho é apresentar, por meio de relato de caso clínico, a associação entre prótese parcial removível (PPR) e prótese parcial fixa (PPF) com o uso de encaixes extracoronários. Paciente Classe III de Kennedy superior procurou atendimento odontológico para confecção de PPR superior sem uso de grampo. No exame clínico e radiográfico verificou-se a necessidade de restauração indireta nos elementos 13 e 23. A partir dos modelos de estudo montados em articulador semiajustável (ASA), o planejamento do caso baseou-se na confecção de PPR superior associada a coroas metalocerâmicas nos caninos superiores utilizando o sistema de encaixe do tipo attachment e PPR inferior convencional. A utilização de próteses fixa e removível conjugadas com encaixes tipo attachment demonstrou ser uma solução viável estética e funcionalmente, proporcionando conforto para a paciente, com prognóstico favorável à manutenção das estruturas (AU).

The combination between fixed and removable dentures opens a range of new possibilities for rehabilitation. The combined prosthesis fittings deserve special attention because they provide advantages in biological, mechanical and aesthetics. The aim of this paper is to present, through a case report, the association between removable partial denture (RPD) and fixed partial denture (FPD) with the use of extra-coronal fittings. Patient with upper Kennedy Class III sought for dental care for making an upper RPD without staple use. Clinical and radiographic exams indicated the need for indirect restoration of elements #13 and #23. From the study models mounted on the semi-adjustable articulator (SAA), the case planning was based on the manufacture of upper RPD associated with metal-ceramic crowns on the maxillary canines using the system plug the attachment type and conventional lower RPD. The use of fixed and removable dentures combined with attachment fittings proved to be a viable solution esthetically and functionally providing comfort to the patient, with a prognosis in favor of maintaining the structures (AU).

Swelling of self-adhesive resin cement increases long-term push-out bond strength of fiber post to dentin

Abstract Aim: To evaluate the long-term post push-out bond strength to dentin, water sorption, solubility and swelling of conventional and self-adhesive dual-cure resin cements. Methods: Forty-eight bovine roots were prepared for fiber post cementation with RelyX ARC and RelyX U100. According to resin cement and storage time (24 h and 6 months), 4 groups were assessed using the push-out test. Water sorption and solubility were performed according to ISO 4049:2009. The swelling coefficient was obtained using cement disks of each material immersed in distilled water until the swelling equilibrium was reached. The mass of dry and swelled polymer and solvent density were used to calculate the coefficient. Statistical data analysis was performed using Student's t-test for water sorption, solubility and swelling coefficient and the Kruskal-Wallis and Dunn multiple comparison tests for push-out analysis with a significance level of 0.05. Results: The immediate bond strength was not significantly different between RelyX ARC (3.09 MPa) and RelyX U100 (3.78 MPa) (p>0.05). RelyX U100 showed higher (p<0.05) bond strength after six months of storage (9.60 MPa) than RelyX ARC (6.65 MPa). The water sorption and solubility values were not significantly different (p>0.05) between groups. The swelling coefficient of the RelyX U100 group was significantly higher than that of the RelyX ARC group (p<0.05). Conclusions: RelyX U100 resin cement showed a higher swelling coefficient than RelyX ARC, and the longitudinal push-out bond strength increased after six months. Clinical significance: The clinical longevity of restorative treatment in root-filled teeth is dependent on the long-term properties and behavior of the cement used for post luting. Results of this study suggest that the selfadhesive resin cement may be a reliable alternative.

Influence of delayed pouring on irreversible hydrocolloid properties

The aim of this study was to evaluate the physical properties of irreversible hydrocolloid materials poured immediately and after different storage periods. Four alginates were tested: Color Change (Cavex); Hydrogum (Zhermack); Hydrogum 5 (Zhermack); and Hydro Print Premium (Coltene). Their physical properties, including the recovery from deformation (n = 3), compressive strength (n = 3), and detail reproduction and gypsum compatibility (n = 3), were analyzed according to ANSI/ADA specification no. 18. Specimens were stored at 23ºC and humidity and were then poured with gypsum immediately and after 1, 2, 3, 4, and 5 days. The data were analyzed by two-way analysis of variance (ANOVA) and Tukey's test at p < 0.05. All of the alginate impression materials tested exhibited detail reproduction and gypsum compatibility at all times. Hydro Print Premium and Hydrogum 5 showed recovery from deformation, as established by ANSI/ADA specification no. 18, after 5 days of storage. As the storage time increased, the compressive strength values also increased. Considering the properties of compounds' recovery from deformation, compressive strength, and detail reproduction and gypsum compatibility, irreversible hydrocolloids should be poured immediately.