Polywave And Monowave Light-Curing Units Effects On Polymerization Efficiency Of Different Photoinitiators / Efeito Da Unidade De Cura Por Luz Polywave E Monowave Na Eficiência De Polimerização De Diferentes Fotoiniciadores

Objective: The objective of this study was to characterize and correlate the absorption spectra of three photoinitiators [camphorquinone (CQ), diphenyl(2,4,6-trimethylbenzoyl) phosphine oxide (TPO) and phenylbis (2,4,6-trimethylbenzoyl)-phosphine oxide (BAPO)], using second or third-generation light curing units (LCU), and to evaluate the degree of conversion and the physical properties of an experimental resin adhesive. Material and methods: Second-generation (Radii-cal® and Emitter D®) and third-generation (Valo® Cordless and Bluephase N®) LCU were assessed regarding spectrum and irradiance rate of emitted light. Also, the photoinitiators (CQ, TPO and BAPO) were characterized by a light absorption spectrum assessed by UV-Vis spectroscopy, degree of conversion and yellowing effect. Statistical analyzes considered two-way ANOVA and post-hoc Tukey test. Results: BAPO presented higher reactivity compared to TPO. Regarding degree of conversion of the photoinitiators activated by different light-curing units, the Emitter D® device promoted a high degree of conversion. BAPO presented the highest yellowing effect values. Conclusions: The emission and absorption characteristics of the photoinitiators were different. The polymerization reaction activated by the second-generation light-curing unit was reduced when using an experimental resin with photoinitiator TPO, and the third-generation light-curing unit showed a higher polymerization potential regardless of the photoinitiator. (AU)

Objetivo: Caracterizar e correlacionar os espectros de absorção de três fotoiniciadores [canforoquinona (CQ), difenil 2,4,6-trimetilbenzil óxido de fosfina (TPO) e óxido de di (2,4,6-trimetilbenzil) difenil fosfina (BAPO)], com unidades de fotoativação (LCU) de segunda ou terceira geração, e avaliar o grau de conversão e as propriedades físicas de um adesivo experimental. Material e métodos: LCU de segunda geração (Radii-cal® e Emitter D®) e terceira geração (Valo® Cordless e Bluephase N®) foram avaliadas quanto ao espectro e taxa de irradiância da luz emitida. Além disso, os fotoiniciadores (CQ, TPO e BAPO) foram caracterizados por um espectro de absorção de luz avaliado por espectroscopia UV-Vis, avaliado o grau de conversão dos adesivos e efeito de amarelamento. A análise estatística empregada foi ANOVA duas vias e teste post-hoc de Tukey. Resultados: BAPO apresentou maior reatividade comparado ao TPO. Em relação ao grau de conversão dos fotoiniciadores ativados por diferentes aparelhos fotopolimerizadores, o dispositivo Emitter D® promoveu um alto grau de conversão. BAPO apresentou os maiores valores de efeito de amarelamento. Conclusões: As características de emissão e absorção dos fotoiniciadores foram diferentes. A reação de polimerização ativada pelas unidades de fotopolimerização de segunda geração foi reduzida com o uso de uma resina experimental com fotoiniciador TPO. As unidades de fotopolimerização de terceira geração apresentaram maior potencial de polimerização independentemente do fotoiniciador. (AU)

Avaliação do efeito da termociclagem na estabilidade de cor e rugosidade superficial de duas resinas compostas comerciais / Evaluation of thermocycling effect on color stability and surface roughness of two commercial resin composite

Objetivo: Avaliar o efeito do envelhecimento térmico por termociclagem na estabilidade de cor e rugosidade superficial de duas resinas compostas, avaliar grau de conversão (GC), sorção (SO), solubilidade (SL) e microdureza. Material e método: Foram confeccionados 10 espécimes (6 mm x 1 mm) para cada resina: Filtek Z350 XT (Z350XT) e Estelite Sigma Quick (ES). Foram avaliados: GC, utilizando um espectrofotômetro no infravermelho, SO e SL. A avaliação da microdureza Vickers (MV) e densidade de ligações cruzadas foi realizada antes e após a imersão em etanol por 24 h. A rugosidade superficial e a estabilidade de cor (CIEDE2000) foram avaliadas antes e após envelhecimento térmico por 2000 ciclos, alternando 30 s a 5°, 37° e 55° C. A estabilidade de cor e translucidez foram avaliadas com um espectrofotômetro. Os dados foram submetidos ao teste t (α=0,05). Resultados: ES apresentou resultados de GC maiores (62,5% ± 3,7) que Z350XT (48,7% ± 6,9) (p=0,004). Ambas resinas apresentaram resultados de SO e SL similares. A MV final da ES diminuiu 13% com relação a inicial (p=0,115). Z350XT apresentou diminuição de 17% (p=0,004). ES apresentou aumento de 115% na rugosidade superficial após a termociclagem (p=0,001), enquanto a Z350XT apresentou diminuição de 35% (p=0,299). ES apresentou menor alteração de cor (0,280 ± 0,093), quando comparada a Z350XT (0,549 ± 0,183). A translucidez foi similar para ambos materiais (ES=30,80; Z350XT=30,35). Conclusão: A termociclagem influenciou na alteração de cor e rugosidade superficial das resinas compostas, demonstrando que podem ser alteradas pela degradação na matriz polimérica.

Objective: To evaluate the thermocycling effect on color stability and surface roughness of two resin composites and also evaluate the degree of conversion (GC), sorption (SO), solubility (SL) and microhardness. Material and method: 10 specimens (6 mm x 1 mm) were made for each resin: Filtek Z350 XT (Z350XT) and Estelite Sigma Quick (ES). The following were evaluated: GC, using an infrared spectroscopy, SO and SL. Vickers microhardness (MV) and cross-link density evaluation was performed before and after immersion in ethanol for 24 hours. Surface roughness and color stability (CIEDE2000) were evaluated before and after thermal aging for 2000 cycles, alternating between 30 s at 5°, 37° and 55° C. Color stability and translucency were assessed with a spectrophotometer. Data were submitted to t test (α= 0.05). Results: ES presented higher GC results (62.5% ± 3.7) than Z350XT (48.7% ± 6.9) (p= 0.004). Both resins showed similar SO and SL results. The final MV of ES decreased 13% in relation to the initial (p= 0.115). Z350XT decreased by 17% (p= 0.004). ES showed a 115% increase in surface roughness after thermocycling (p= 0.001), while the Z350XT showed a 35% decrease (p= 0.299). ES showed less color change (0.280 ± 0.093) when compared to Z350XT (0.549 ± 0.183). The translucency was similar for both materials (ES= 30.80; Z350XT= 30.35). Conclusion: Thermocycling influenced the change in color stability and surface roughness of composite resins, demonstrating that they may be altered by degradation in the polymer matrix.

A Bibliometric analysis of articles published in Brazilian Dental Journal over 30 years

Abstract This study assessed bibliometric characteristics of all articles published in Brazilian Dental Journal (BDJ) in its 30 years of existence (1990-2019) and factors associated with citation rates. A document search was carried out in Scopus in December, 2019 and information about the articles were exported, including citations. Type of study and main subject in each article were categorized. Number of citations was categorized in tertiles. Logistic regression models were used to assess the association between variables related to articles' characteristics and number of citations. In 30 years, 1705 articles were published and 18507 citations received, with average 57 articles and 334 pages published yearly and 10.9 cites/doc. The most frequent types of study were laboratorial (63%), clinical (18.5%), and case reports (11%); the main subjects were dental materials (21.6%), endodontics (19.3%), and oral pathology/stomatology (13.1%). Most articles had origin in Brazil (90%), followed by USA (4.6%) and UK (1.5%). Aside from BDJ, Journal of Endodontics (3.5%) and International Endodontic Journal (2.2%) were journals that most often cited BDJ. Main origins of citations were Brazil (36.7%), USA (10.6%), and India (9%). Older articles had higher odds to be highly cited (12% increase/year), longer articles had lower odds (9% decrease/page). Narrative reviews and epidemiological studies were associated with more citations and systematic reviews with less citations. In conclusion, BDJ covered many subjects and study types in 30 years, showing increased growth in international audience. The journal may be regarded as one of the leading Brazilian journals in dentistry published in English.

Resumo Este estudo avaliou as características bibliométricas de todos os artigos publicados no Brazilian Dental Journal (BDJ) em seus 30 anos de existência (1990-2019) e fatores associados com taxas de citação. Uma busca pelos documentos foi realizada no Scopus em Dezembro de 2019 e informações acerca dos artigos foram exportadas, incluindo citações. Tipo de estudo e principal assunto em cada artigo foram categorizados. Número de citações foi categorizado em tercis. Modelos de regressão logística foram usados para avaliar a associação entre as variáveis relacionadas às características dos artigos e o número de citações. Em 30 anos, 1705 artigos foram publicados e 18507 citações recebidas, com média de 57 artigos e 334 páginas publicadas ao ano e 10,9 citações/documento. Os tipos de estudo mais frequentes foram laboratorial (63%), clínico (18,5%) e relato de caso (11%); os principais assuntos foram materiais dentários (21,6%), endodontia (19,3%) e patologia oral/estomatologia (13,1%). A maioria doas artigos teve origem do Brasil (90%), seguido dos EUA (4,6%) e Reino Unido (1,5%). Além do BDJ, Journal of Endodontics (3,5%) e International Endodontic Journal (2,2%) foram os periódicos que mais citaram o BDJ. As principais origem das citações foram Brasil (36,7%), EUA (10,6%) e Índia (9%). Artigos mais antigos tiveram maiores chances de serem altamente citados (aumento de 12% ao ano), artigos mais longos tiveram menores chances (redução de 9% por página). Revisões narrativas e estudos epidemiológicos foram associados com mais citações e revisões sistemáticas com menos citações. Em conclusão, o BDJ cobriu diversos assuntos e tipos de estudo em 30 anos, mostrando contínuo crescimento na audiência internacional. O periódico pode ser considerado um dos líderes entre as revistas brasileiras de odontologia publicadas em inglês.

Long-term bonding efficacy of adhesives containing benzodioxioles as alternative co-initiators

Abstract This study evaluated the three-year lifespan of the bond to dentin of experimental self-etch adhesives containing benzodioxole derivatives - 1,3-benzodioxole (BDO) and piperonyl alcohol (PA) - as co-initiator alternative to amines. Adhesive resins were formulated using Bis-GMA, TEGDMA, HEMA, camphorquinone and different co-initiators: BDO, PA or ethyl 4-dimethylamino benzoate (EDAB - amine). An experimental self-etch primer was used to complete the two-step, self-etch adhesive system. Clearfil SE Bond (CSE) was used as commercial reference. Bond strength to human dentin was assessed by microtensile bond strength (µTBS) test, and failure mode was classified. Morphology of the dentin bonding interface was assessed via scanning electron microscopy (SEM). Irrespective of the dental adhesives evaluated, µTBS was higher after 24 hours compared with that after 1.5 and 3 years (p ≤ 0.001). However, adhesives with BDO and PA as co-initiators showed significantly higher bond strength than the bonding resin with EDAB (p ≤ 0.002), independent of the time evaluated. The commercial adhesive CSE showed similar bond strength compared with the other groups (p ≥ 0.05). Mixed failures were mainly observed after 24 hours, while adhesive failures were more frequently observed after 1.5 and 3 years. No notable differences in homogeneity and continuity along the bonded interfaces were detected among the materials in the SEM analysis. In conclusion, benzodioxole derivatives are feasible alternative co-initiators to tertiary amine in camphorquinone-based self-etching dental adhesive formulations.

Fifty years of Brazilian Dental Materials Group: scientific contributions of dental materials field evaluated by systematic review

ABSTRACT Objective A systematic review was conducted to analyze Brazilian scientific and technological production related to the dental materials field over the past 50 years. Material and Methods This study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (Prisma) statement. Searches were performed until December 2014 in six databases: MedLine (PubMed), Scopus, LILACS, IBECS, BBO, and the Cochrane Library. Additionally, the Brazilian patent database (INPI - Instituto Nacional de Propriedade Industrial) was screened in order to get an overview of Brazilian technological development in the dental materials field. Two reviewers independently analyzed the documents. Only studies and patents related to dental materials were included in this review. Data regarding the material category, dental specialty, number of documents and patents, filiation countries, and the number of citations were tabulated and analyzed in Microsoft Office Excel (Microsoft Corporation, Redmond, Washington, United States). Results A total of 115,806 studies and 53 patents were related to dental materials and were included in this review. Brazil had 8% affiliation in studies related to dental materials, and the majority of the papers published were related to dental implants (1,137 papers), synthetic resins (681 papers), dental cements (440 papers), dental alloys (392 papers) and dental adhesives (361 papers). The Brazilian technological development with patented dental materials was smaller than the scientific production. The most patented type of material was dental alloys (11 patents), followed by dental implants (8 patents) and composite resins (7 patents). Conclusions Dental materials science has had a substantial number of records, demonstrating an important presence in scientific and technological development of dentistry. In addition, it is important to approximate the relationship between academia and industry to expand the technological development in countries such as Brazil.

Diclofenac in hyaluronic acid gel: an alternative treatment for actinic cheilitis

OBJECTIVE: Actinic cheilitis (AC) is a precancerous lesion of the lip vermillion caused by prolonged exposure to ultraviolet light. The aim of this study was to evaluate the effect of 3 percent diclofenac in 2.5 percent hyaluronic acid gel in the treatment of AC. METHODS: Thirty-four patients with chronic AC were treated twice a day with topical diclofenac during a period of 30 to 180 days. The individuals were followed up every 15 days by means of clinical examination and digital photographic documentation. RESULTS: Of the 27 patients that completed the study, 12 (44 percent) showed complete remission of the whitish plaques and exfoliative areas, and 15 (56 percent) had partial remission of the clinical picture of cheilitis. The latter group was submitted to excision of the leukoplakic areas which diagnosis varied from mild to moderate epithelial dysplasia. CONCLUSIONS: The results suggest a promising role for diclofenac in hyaluronic acid gel in the treatment of AC. This treatment has the advantages of not being invasive and showing few side effects.

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.