Tetrahydrofuran as solvent in dental adhesives: cytotoxicity and dentin bond stability.

OBJECTIVES: The aim of this study was to investigate the cytotoxicity and 1-year dentin bond stability of solvated etch-and-rinse dental adhesives based on tetrahydrofuran (THF), acetone, or ethanol, containing water or not. MATERIALS AND METHODS: Seven primers were prepared using the following solvents: THF, acetone, ethanol, water, THF/water, acetone/water, and ethanol/water. Bovine dentin was used, and specimens for microtensile bond strength (µTBS) test were prepared. Specimens were tested after storage in distilled water for 24 h or 1 year. Cytotoxicity of the solvents was evaluated in 3T3/NIH mouse fibroblasts using a colorimetric 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay after exposure for 24 h. RESULTS: No significant differences were detected among solvents after storage for 24 h, except for the water-based group, which showed the lowest µTBS values. After storage for 1 year, the THF-based adhesive system resulted in more stable bonds. Yet, THF showed an intermediate cytotoxicity when compared with the other solvents, being less toxic than phosphate monomer and similar to 2-hydroxyethyl methacrylate. CONCLUSION: THF seems to be a suitable solvent for adhesive systems. CLINICAL RELEVANCE: THF is a promising solvent that can be used to improve dentin bond stability.

The effect of repeated firings on the color of feldspathic ceramics.

The aim of this study was to determine the extent to which repeated firings would change the color of feldspathic ceramics. Specimens were fabricated from five commercially available feldspathic ceramics using a circular stainless steel matrix 11 mm in diameter and 1.0 mm thick (n = 10, shade = A3). Repeated firings were performed and color analysis was completed with a colorimeter using the CIELA B color coordinates. Two-way ANOVA was used to analyze the data, followed by Tukey's post-hoc test (a = 0.05). Three factors were used as determinants: a, a measure of the chroma along the red-green axis; b, a measure of the chroma along the yellow-blue axis; and L, a measure of the lightness-darkness of the specimen on a scale from 0 (black) to 100 (white). The results indicated that a and b values increased and L values decreased after repeated firings, resulting in reddish, yellowish, and darker specimens, respectively (P = 0.001). As the number of firings increased, significant color alterations occurred in the color parameters of the specimens. These alterations resulted in color changes (delta E) that could be considered unacceptable in clinical practice.

Effects of cervical restorations on the periodontal tissues: 5-year follow-up results of a randomized clinical trial.

OBJECTIVE: This study evaluated the effect of resin composite restorations of non-carious cervical lesions (NCCLs) on the occurrence/progression of gingival recession (GR), considering different tooth isolation techniques. METHODS: A randomized controlled split-mouth and blinded trial was carried out. Patients (n = 38) with at least two NCCLs were included. Before the cervical restoration placement, the NCCLs (181 teeth) were randomly allocated into two treatment groups according to the tooth isolation techniques: cotton roll or rubber dam. Experienced, trained, blinded, and calibrated examiners performed periodontal evaluations at baseline and 5-year follow-up, using a periodontal probe. Restorations were assessed with the FDI criteria. Thirty-two patients (154 teeth) were evaluated at 5 years. The occurrence/progression of GR between baseline and follow-up was considered the primary outcome. The relative risk (RR) and 95 % confidence interval (95 %CI) were calculated by Poisson regression (α < 0.05). RESULTS: After 5 year, 31 teeth (13.6 %) presented occurrence/progression of GR. In the multivariate analyses, the occurrence/progression of GR was associated with the use of rubber dam isolation (RR; 95 %CI: 2.65; 1.01-7.00) and a lack of marginal adaptation of the restoration (RR; 95 %CI: 10.98; 2.31-52.30). Toothbrush stiffness, use of abrasive dentifrice, tooth type, and the presence of biofilm or gingivitis did not present a statistically significant higher risk for occurrence/progression of GR. CONCLUSION: The use of rubber dam isolation associated with retraction clamp and the lack of a proper marginal adaptation of the composite restorations are risk indicators for the occurrence/progression of GR in individuals who received a restoration for an NCCL. CLINICAL SIGNIFICANCE: Isolation with a rubber dam and dental clamps may promote GR in sites with restored NCCLs. Moreover, clinical examinations for lack of marginal adaptations of the restorations may be included in a clinical setting.

Resin-dentin bond strength of 10 contemporary etch-and-rinse adhesive systems after one year of water storage.

To compare the resin-dentin bond degradation of 10 contemporary etch-and-rinse adhesive systems after one year of water storage, 100 bovine incisors were randomly separated into 10 groups and their superficial coronal dentin was exposed. According to manufacturers' instructions, dentin surfaces were bonded with one of seven two-step etch-and-rinse adhesives or one of three three-step etch-and-rinse adhesives. Composite buildups were constructed incrementally. Restored teeth were sectioned to obtain sticks (0.5 mm²). The specimens were subjected to a microtensile bond strength test after storage in distilled water (at 37°C) for one year. Data (MPa) were analyzed using Kruskal-Wallis and Tukey's tests at α = 0.05. Of the adhesives tested, One Step, All Bond 2, and Optibond FL attained the highest bond strength to dentin after one year in water storage, while Magic Bond DE and Master Bond presented a high number of premature debonded flaws.

Effectiveness of different carbamide peroxide concentrations used for tooth bleaching: an in vitro study.

OBJECTIVES: This in vitro study evaluated the effectiveness of three carbamide peroxide concentrations used for tooth bleaching treatments. MATERIAL AND METHODS: Sixty bovine dental slabs (6x6x3 mm) were obtained, sequentially polished, submitted to artificial staining (baseline) and randomized into four groups (n=15), according to the bleaching agent concentration: distilled water (control), 10% (CP10), 16% (CP16) or 37% (CP37) carbamide peroxide. CP10 and CP16 were covered with 0.2 mL of the respective bleaching gels, which were applied on enamel surface for 4 h/day during two weeks. Samples of CP37 were covered with 0.2 mL of the bleaching gel for 20 min. The gel was light activated by two 40-s applications spaced by 10-min intervals. The gel was renewed and applied 3 times per clinical session. This cycle was repeated at 3 sessions with 5 days of interval between them. Tooth shade evaluations were done with a digital spectrophotometer at T0 (baseline), T1 (after 1-week of treatment) and T2 (1-week post-bleaching). Tooth shade means were statistically analyzed by Kruskal-Wallis and Friedman's tests and color parameters were analyzed by two-way ANOVA and Tukey's test (p<0.05). RESULTS: At T1 and T2 evaluations, tooth shade was significantly lighter than at baseline for all treatment groups, considering the color parameters ΔL*, Δa*, Δb*, ΔE* (p<0.001) or tooth shade means (p<0.001). CP37 group showed lower shade mean change than CP10 and CP16 at T1 (p<0.01), but this difference was not statistically significant at T2 (p>0.05). CONCLUSIONS: One week after the end of the treatment, all carbamide peroxide concentrations tested produced similar tooth color improvement.

Color stability of a nanofill composite: effect of different immersion media.

OBJECTIVE: The aim of this in vitro study was to evaluate the color stability of a nanofill composite resin (Filtek Z350) in different immersion media. MATERIALS AND METHODS: Twelve resin-based composite specimens were prepared using a silicon cylindrical mold measuring congruent with 1mm of thickness and congruent with 10mm of diameter. Specimens were light-cured for 40 s from both sides using a LED Radii at 1400 mW/cm(2) and were randomized into 4 groups (n= 3) according to immersion media: coffee, yerba mate, grape juice or water (control solution). A digital spectrophotometer was used to evaluate the color changes at baseline and at 1-week after immersion in each solution. Specimens were stored in the different staining media for 4 h/day during 1 week. The color differences (DE) were analyzed by paired t-test and one-way ANOVA with complementary Tukey test (p<0.05). RESULTS: After 1-week of immersion, a perceptive color change for the group stored in the grape juice compared to baseline (p=0.008) was observed. Coffee and yerba mate did not show any color changes visible for the human eyes or significantly different from the control group (p>0.05) CONCLUSIONS: The findings of the present study suggest that the tested nanofill resin-based composite was susceptible to staining by substances present in the grape juice.

A survey of oral and maxillofacial biopsies in children: a single-center retrospective study of 20 years in Pelotas-Brazil.

Despite the large number of published cases about oral and maxillofacial pediatric lesions, the literature is scarce on epidemiological studies regarding the prevalence of these entities. This study retrieved oral and maxillofacial pediatric lesions from the Center of Diagnosis of Oral Diseases (CDDB) at the Dental School of the Federal University of Pelotas (UFPEL), comprising a 20-year period (1983-2002). From the total of 9,465 biopsies received in this period, 625 (6.6%) were from children aged 0 to 14 years. Regardless of the histopathological diagnosis, patient data referring to lesion location, sex and age were collected. Diagnoses were grouped in 13 categories. As much as 89% of the cases occurred in patients aged 7 to 14 years (53% in females and 47% in males). Mucocele (17.2%) was the most common type of lesion, followed by dentigerous cyst (8.6%). In the category of odontogenic tumors, odontoma was the most frequent lesion (64.2%). Malignant lesions were observed in a small section of the sample (1.2%). Generally, the results of the present study are in line with those reported in the literature concerning the most prevalent lesions in the pediatric population. Most lesions were benign, and malignant lesions were diagnosed in a very small part of the sample.

Effectiveness of different carbamide peroxide concentrations used for tooth bleaching: an in vitro study

OBJECTIVES: This in vitro study evaluated the effectiveness of three carbamide peroxide concentrations used for tooth bleaching treatments. MATERIAL AND METHODS: Sixty bovine dental slabs (6x6x3 mm) were obtained, sequentially polished, submitted to artificial staining (baseline) and randomized into four groups (n=15), according to the bleaching agent concentration: distilled water (control), 10% (CP10), 16% (CP16) or 37% (CP37) carbamide peroxide. CP10 and CP16 were covered with 0.2 mL of the respective bleaching gels, which were applied on enamel surface for 4 h/day during two weeks. Samples of CP37 were covered with 0.2 mL of the bleaching gel for 20 min. The gel was light activated by two 40-s applications spaced by 10-min intervals. The gel was renewed and applied 3 times per clinical session. This cycle was repeated at 3 sessions with 5 days of interval between them. Tooth shade evaluations were done with a digital spectrophotometer at T0 (baseline), T1 (after 1-week of treatment) and T2 (1-week post-bleaching). Tooth shade means were statistically analyzed by Kruskal-Wallis and Friedman's tests and color parameters were analyzed by two-way ANOVA and Tukey's test (p<0.05). RESULTS: At T1 and T2 evaluations, tooth shade was significantly lighter than at baseline for all treatment groups, considering the color parameters ΔL*, Δa*, Δb*, ΔE* (p<0.001) or tooth shade means (p<0.001). CP37 group showed lower shade mean change than CP10 and CP16 at T1 (p<0.01), but this difference was not statistically significant at T2 (p>0.05). CONCLUSIONS: One week after the end of the treatment, all carbamide peroxide concentrations tested produced similar tooth color improvement.

Restauración semidirecta de resina compuesta: una alternativa para dientes posteriores: reporte de caso clínico / Semi-direct composite resin restoration: an alternative for posterior teeth: case report

Las restauraciones semidirectas de resina compuesta para el tratamiento de dientes posteriores con extensa pérdida de tejido dentario surgieron hace algunos años como una alternativa de tratamiento frente a las restauraciones directas en resina, amalgama y restauraciones cerámicas. Utilizando una técnica que permita la confección extraoral de la restauración, es posible optimizar las condiciones clínicas de trabajo y mejorar las propiedades finales del material restaurador. El presente trabajo tiene por objetivo reportar un caso clínico donde se utilizó una restauración semidirecta de resina compuesta para substituir una restauración defectuosa de amalgama. En este trabajo se describen los procedimientos clínicos realizados y se discuten las ventajas y desventajas asociadas a la técnica utilizada

Semi-direct composite restorations to treat teeth with large tooth loss appeared recently as an alternative to the direct restorations (amalgam and composite) and the ceramic restorations. Using an extraoral technique to produce the restoration will improve the clinical conditions and the mechanical properties. Here, we reported a case where a semi-direct composite restorations was employed to replace a defective large amalgam restoration. The report describes the clinical procedures and discuss the advantages and disadvantages associated to the technique

Color stability of a nanofill composite: effect of different immersion media

OBJECTIVE: The aim of this in vitro study was to evaluate the color stability of a nanofill composite resin (Filtek Z350) in different immersion media. MATERIALS AND METHODS: Twelve resin-based composite specimens were prepared using a silicon cylindrical mold measuring ≅1mm of thickness and ≅ 10mm of diameter. Specimens were light-cured for 40 s from both sides using a LED Radii at 1400 mW/cm² and were randomized into 4 groups (n= 3) according to immersion media: coffee, yerba mate, grape juice or water (control solution). A digital spectrophotometer was used to evaluate the color changes at baseline and at 1-week after immersion in each solution. Specimens were stored in the different staining media for 4 h/day during 1 week. The color differences (DE) were analyzed by paired t-test and one-way ANOVA with complementary Tukey test (p<0.05). RESULTS: After 1-week of immersion, a perceptive color change for the group stored in the grape juice compared to baseline (p=0.008) was observed. Coffee and yerba mate did not show any color changes visible for the human eyes or significantly different from the control group (p>0.05) CONCLUSIONS: The findings of the present study suggest that the tested nanofill resin-based composite was susceptible to staining by substances present in the grape juice.

Frequencia de pinos intrarradiculares utilizados em procedimentos de reconstrução dentária na Faculdade de Odontologia da Universidade Federal de Pelotas / Frequence of posts used in dental reconstruction procedures in the patients assisted at Dentistry School of Federal University of Pelotas

Objetivo: Realizar um levantamento dos pinos intracanais utilizados nos procedimentos de reconstrução dentária, na Faculdade de Odontologia da Universidade Federal de Pelotas, e verificar sua relação com a técnica restauradora e localização no arco dentário. Metodologia: Os prontuários arquivados no Serviço de Triagem, no período entre 2005 e 2008, foram analisados quanto ao tipo de pino intracanal, técnica restauradora e localização no arco dentário. Os dados foram analisados estatisticamente (teste Qui-quadrado), considerando p < 0,05. Resultados: De um total de 5.566 registros, 192 (4,7%) procedimentos restauradores utilizaram os seguintes tipos de retontores: 107 (55.7%) metálicos fundidos, 38 (19,7%) fibra de vidro, 27 (14,1%) metálicos, 14 (7,2%) fibra de carbono e 6 (3,1%) fio de aço. Restaurações indiretas e diretas foram realizadas em 51% e 49% dos casos, respectivamente. Pinos metálicos fundidos foram mais associados a restaurações indiretas (p < 0,001). Considerando a sua localização na arcada, não houve diferença significativa entre os pinos utilizados na região anterior e posterior (p = 0,457).Conclusões: Durante o período de estudo, a maioria dos procedimentos de reconstrução dentária em dentes tratados endodonticamente foram realizados sem utilização de retentores intracanais. Porém, pinos metálicos fundidos foram mais frequentemente associados a coroas unitárias protéticas.

Purpose: To accomplish a rising of posts used in dental reconstruction procedures, at the School of Dentistry of Federal University of Pelotas, and verify it relationship with the restoring technique and location in the dental arch.Methods: The handbooks filed in the Service of Patient Selection, in the period understood between 2005 and 2008, it were appreised as for the post type, recovering technique and location in the dental arch. The data were submitted to the statistical analysis (test Qui-square), considering p<0,05. Results: From the total of 5.566 handbooks filed, 192 (4,7%) recovering procedures were accomplished using the following types of posts: 107 (55,7%) melted metallic, 38 (19,7%) glass fiber, 27 (14,1%) metallic, 14 (7,2%) carbon fiber and 6 (3,1%) posts of steel. Prosthetic crowns (indirects) and direct recovering were accomplished in 51% and 36,9% of the cases, respectively. Melted metallic posts were more associated to indirect restorations (p<0,001) . Considering the position of the tooth in the arcade, there was not statistic significant differences among the types of posts used in the anterior and posterior area (p=0,457). Conclusions: During the period of this study, the majority of recovering procedures of endodontically treated teeth was accomplished without the use of posts. However, melted metallic posts were more associated to indirect restorations.

A survey of oral and maxillofacial biopsies in children: a single-center retrospective study of 20 years in Pelotas-Brazil

Despite the large number of published cases about oral and maxillofacial pediatric lesions, the literature is scarce on epidemiological studies regarding the prevalence of these entities. This study retrieved oral and maxillofacial pediatric lesions from the Center of Diagnosis of Oral Diseases (CDDB) at the Dental School of the Federal University of Pelotas (UFPEL), comprising a 20-year period (1983-2002). From the total of 9,465 biopsies received in this period, 625 (6.6%) were from children aged 0 to 14 years. Regardless of the histopathological diagnosis, patient data referring to lesion location, sex and age were collected. Diagnoses were grouped in 13 categories. As much as 89 percent of the cases occurred in patients aged 7 to 14 years (53% in females and 47 percent in males). Mucocele (17.2%) was the most common type of lesion, followed by dentigerous cyst (8.6%). In the category of odontogenic tumors, odontoma was the most frequent lesion (64.2%). Malignant lesions were observed in a small section of the sample (1.2%). Generally, the results of the present study are in line with those reported in the literature concerning the most prevalent lesions in the pediatric population. Most lesions were benign, and malignant lesions were diagnosed in a very small part of the sample.

Restabelecendo a estética dos dentes anteriores com clareamento e restaurações em resina composta: relato de caso clínico / Recovering esthetics in anterior teeth with bleaching and composite restorations: case report

A crescente demanda por procedimentos estéticos e tratamentos dentários não-invasivos favoreceu o surgimento de diferentes abordagens para solução de problemas de alteração de cor dentária. Com o desenvolvimento das técnicas de clareamento dental e da odontologia adesiva, é possível oferecer tratamentos conservadores para recuperação de dentes anteriores comprometidos. O presente caso clínico relata a associação de duas técnicas de clareamento para dentes vitais escurecidos e de um compósito restaurador nanoparticulado para restauração de incisivos centrais superiores. Resultados estéticos satisfatórios foram obtidos com a combinação de opções de tratamento minimamente invasivas para restabelecimento da cor e forma dos dentes...

The increasing demand for esthetic, non-invasive dental procedures led to the introduction of a number of approaches to resolve problems from tooth discolorations. The development of tooth bleaching and adhesive techniques made possible to provide conservative treatments to restore compromised anterior teeth. This case report presents the association of two bleaching techniques for vital discolored teeth and the use of a nanofilled composite resin to restore the maxillary central incisors. It was concluded that satisfactory results can be achieved through the association of minimally invasive approaches to reestablish tooth color and shape...