Abstract This study analyzed the prevalence of lectures involving esthetics in the scientific program of Brazilian dental conferences and the gender distribution of speakers. All lectures presented in three dental conferences (Bahia, São Paulo, and Goiás states) held from 2016 to 2020 were evaluated. Three investigators individually divided the lectures according to the specialties recognized by the Brazilian Federal Council of Dentistry (FCD) based on their titles. The lectures were also classified as involving or not esthetics, and the speaker`s gender was recorded. Descriptive statistical analyses were performed, and Chi-square tests assessed possible associations between factors. The words most cited in the titles of the lectures were “esthetic” (13.6%), “dentistry” (9.9%), and “treatment” (8.1%). Oral diseases were barely mentioned in the titles (up to 1.3%). The highest number of lectures was observed for the specialty of Restorative Dentistry (22.3%), followed by Prosthodontics (18.5%). Approximately one-third of lectures involved some aesthetic aspect, but this percentage ranged from 71.9 to 78.6% for the two specialties with more lectures. Regarding the speaker`s gender, the inequity was higher for lectures involving esthetics (81.6% of males) than for topics unrelated to esthetics (66.7%). More male speakers than females were observed for all specialties. The highest gender gap was observed for Pediatric Dentistry with 62.4% male speakers, although only 10.6% of FCD registered specialists were men. In conclusion, the Brazilian dental conferences analyzed seemed to favor offering lectures dealing with esthetic topics and male speakers.

Resumo Este estudo analisou a prevalência de palestras envolvendo estética na programação científica de congressos de Odontologia brasileiros, e a distribuição do gênero dos palestrantes. Todas as palestras apresentadas em três congressos de Odontologia (CIOBA, CIOGO, and CIOSP) entre 2016 e 2020 foram avaliadas. Três avaliadores utilizaram os títulos das palestras para dividi-las entre as especialidades reconhecidas pelo Conselho Federal de Odontologia (CFO) do Brasil. As palestras foram também classificadas como envolvendo ou não estética, e o gênero do palestrante foi registrado. Análises estatísticas descritivas foram realizadas, e testes de Qui-quadrado avaliaram possíveis interações entre fatores. A palavra mais citada nos títulos das palestras foi “estética” (13,6%), seguido por “odontologia” (9,9%) e “tratamento” (8,1%). Doenças orais foram raramente mencionadas nos títulos (até 1,3%). O maior número de palestras foi observado para a especialidade de Dentística (22,3%), seguido por Prótese Dental (18,3%). Aproximadamente um terço das palestras envolviam algum aspecto estético, com porcentagens entre 71,9 a 78,6% para as duas especialidades com mais palestras. Em relação ao gênero do palestrante, a inequidade foi maior para palestras envolvendo estética (81,6% de homens) que para tópicos não relacionadas à estética (66,7%). Mais palestrantes do sexo masculino que feminino foram observados para todas as especialidades. A maior discrepância entre os gêneros foi observada para Odontopediatria, uma especialidade com 62,4% dos palestrantes do sexo masculino, embora apenas 10,6% dos especialistas registrados no CFO eram homens. Como conclusão, os congressos de Odontologia Brasileiros parecem preferir palestras abordando tópicos de estética e palestrantes do sexo masculino.

Abstract This study evaluated the background and effect of surrounding colors on the color blending of a single-shade composite used in a thin layer. Disc-shaped specimens (1.0 mm thickness) were built with the Vittra APS Unique composite surrounded (dual specimens) or not surrounded (simple specimens) by a control composite (shade A1, A2, or A3). Simple specimens were also built with only control composites. The specimen color was measured against white and black backgrounds with a spectrophotometer (CIELAB system). The whiteness index for dentistry (WID) was calculated for simple specimens. Differences (ΔE00) in color and translucency parameters (ΔTP00) between the simple/dual specimens and the controls were calculated. The translucency adjustment potential (TAP) and color adjustment potential (CAP) were estimated based on the ratios between data from simple and dual specimens. The Vittra APS Unique composite showed higher WID values than the controls. No differences between ΔTP00_SIMPLE and ΔTP00_DUAL were observed for any of the shades. The composite shade did not affect TAP values. The lowest values of ΔE00_SIMPLE and ΔE00_DUAL were observed for shade A1 regardless of the background color. For the white background, ΔE00_SIMPLE values did not differ from those of ΔE00_DUAL for all shades. Only A1 showed ΔE00_DUAL values lower than ΔE00_SIMPLE when the black background was used. The highest modulus of CAP (negative values for the white background) was observed when shade A1 surrounded the Vittra APS Unique composite. The color blending ability of the single-shade resin composite used in a thin layer was affected by both the surrounding shade and background color.

Resumo Este estudo avaliou o efeito da cor circundante e da espessura da amostra no potencial de ajuste de cor (PAC) de uma resina monocromática. O compósito Vittra APS Unique foi circundado (amostras duplas) ou não (amostras simples) com um compósito controle (cor A1, A2 ou A3). Amostras simples do compósito controle também foram confeccionadas. A opacidade e o índice de brancura para odontologia (IBO) foram calculados para as amostras simples. As diferenças de cor entre amostras simples (ΔE*SIMPLE) / duplas (ΔE*DUAL) e os controles foram calculados. PAC foi calculado baseado na razão entre ΔE* SIMPLE e ΔE* DUAL. O compósito testado apresentou menor opacidade (53 a 62% vs. 80 a 93%) e maior IBO (≈ 42 vs. 18 a 32) que os controles. Independente da espessura da amostra (1,0/ 1,5 mm), os valores mais baixos de ΔE* SIMPLE (11,1/ 10,8) e ΔE*DUAL (7,2/ 6,1) foram observadas quando a resina circundante era A1. A cor A3 resultou em maior ΔE*SIMPLE (16,4/ 17,1) e ΔE* DUAL (11,3/ 12,3) do que A2 (ΔE*SIMPLE = 13,4/ 14,6; e ΔE* DUAL = 9,7/ 10,3). A espessura das amostras afetou significativamente o PAC (0,35 e 0,44 para 1,0 e 1,5 mm, respectivamente) apenas para a cor A1, que teve os maiores valores de PAC. A cor A3 resultou nos maiores valores de PAC (0,31) que A2 (0,27) quando amostras de 1,0 mm de espessura foram usadas, mas valores similares foram observados para amostras de 1,5 mm (≈ 0,29). Como conclusão, tanto a cor circundante como a espessura das amostras podem afetar o PAC de um compósito resinoso monocromático.

Abstract This study evaluated the effect of surrounded shade and specimens` thickness on the color adjustment potential (CAP) of a single-shade composite. The composite Vittra APS Unique was surrounded (dual specimens) or not (simple specimens) by a control composite (shade A1, A2, or A3). Simple specimens of the control composite were also confectioned. Opacity and whiteness index for dentistry (WID) were calculated for simple specimens. Color differences between the simple (ΔE*SIMPLE)/ dual specimens (ΔE*DUAL) and the controls were calculated. CAP was calculated based on the ratio between ΔE* SIMPLE and ΔE* DUAL. The tested composite presented lower opacity (53 to 62% vs. 80 to 93%) and higher WID (≈ 42 vs. 18 to 32) than controls. Irrespective of the specimens’ thickness (1.0/ 1.5 mm), the lowest values of ΔE* SIMPLE (11.1/ 10.8) and ΔE*DUAL (7.2/ 6.1) were observed using the surrounding shade A1. The shade A3 yielded higher ΔE*SIMPLE (16.4/ 17.1) and ΔE* DUAL (11.3/ 12.3) than the A2 (ΔE*SIMPLE = 13.4/ 14.6; and ΔE* DUAL = 9.7/ 10.3). The specimen`s thickness significantly affected the CAP (0.35 and 0.44 for 1.0 and 1.5 mm, respectively) only for shade A1, which had the highest CAP values. The shade A3 resulted in higher CAP values (0.31) than A2 (0.27) when 1.0-mm thick specimens were used, but similar values were observed for 1.5 thick specimens (≈ 0.29). In conclusion, both surrounding shade and specimen thickness can affect the CAP of a single-shade resin composite.

Abstract Objective To evaluate the effect of the association between external and internal tooth bleaching on color changes in dentin and enamel, individually or recombined, previously stained with triple antibiotic paste (TAP). Methodology Forty enamel-dentin specimens from bovine incisors were separated into ten blocks according to similarity in their whiteness index (WID). Three specimens within each block were stained by dentin exposure to TAP, and the remaining specimen was used as control to estimate color changes. Specimens were sectioned to separate tissues, and dentin and enamel colors were measured individually and after being recombined. Alterations in color (CIEDE2000 - ΔE00) and translucency parameter (TP) resulting from staining were estimated by color difference between stained and control specimens. The contribution of each tissue to the color change (CTCC) was also calculated. Non-sectioned stained specimens were bleached by applying sodium perborate on dentin, associated or not with 35% hydrogen peroxide on enamel. Color changes caused by bleaching procedures were estimated and data were analyzed using the paired t-test or Two-way repeated measures ANOVA. Results TAP caused more pronounced changes in dentin, but enamel color was also affected. Both protocols presented a similar ΔE00, and dentin showed the greater color change. After exposure to TAP, we observed a reduction in WID; WID values were the same for bleached and control specimens regardless of protocol. We found no significant effect of substrate and bleaching technique on TP. Enamel played a more critical role in color changes caused by either staining or bleaching procedures. Conclusion Enamel color played a greater role on tooth color changes than dentin. External and internal bleaching association did not improve bleaching effect on specimens stained with TAP.

Resumo Este ensaio clínico avaliou o efeito do uso preemptivo do anti-inflamatório não-esteroidal piroxicam em dose única 30 minutos antes do clareamento de consultório na prevenção de sensibilidade dentária (SD) relatada pelos pacientes. Cinquenta pacientes foram submetidos a duas sessões de clareamento dental em consultório com peróxido de hidrogênio a 35% por 2 sessões, consistindo de aplicação única de 45 minutos, com um intervalo de 7 dias entres as sessões. Trinta minutos antes do procedimento, o paciente recebia aleatoriamente dose única de piroxicam (200 mg) ou do placebo em um desenho duplo-cego, randomizado e cruzado. A SD foi avaliada usando a escalas de gradação verbal (EGV) e visual analógica (EVA) durante o procedimento clareador e 24h após o procedimento. As mudanças de cor foram avaliadas usando a escala Vita Bleachedguide uma semana após cada sessão de clareamento. O risco de SD foi calculado a partir de EGV a analisado pelo teste de McNemar, enquanto o nível de SD foi analisada pelo teste de Mann-Whitney. Para EVA, testes T foram usados para comparar dados dos tratamentos em cada tempo de avaliação. Dados de mudança de cor foram submetidos aos testes de Wilcoxon e Mann-Whitney (α=0.05). A administração preemptiva de piroxicam não afetou o risco e nível de SD quando comparado ao placebo, independentemente do tempo de avaliação. A sequencia de tratamento não afetou a efetividade do clareamento. Como conclusão, a administração de dose única de piroxicam previamente ao clareamento dental de consultório não foi efetiva em reduzir significantemente o risco e nível de SD.

Abstract This clinical trial evaluated the effect of preemptive use of the non-steroidal anti-inflammatory drug piroxicam in a single dose 30 min prior to in-office bleaching on the prevention of tooth sensitivity (TS) reported by patients. Fifty patients were submitted to two sessions of in-office tooth bleaching with 35% hydrogen peroxide used for 2 sessions, each consisting of a single 45-min application, with an interval of 7 days between session. Thirty minutes prior to the procedure, the patient randomly received a single dose of piroxicam (200 mg) or placebo in a double-blind, randomized, crossover design. The TS was evaluated using verbal rate (VRS) and visual analog (VAS) scales during the bleaching procedure and at 24 h after each session. The color changes were assessed by the Vita Bleachedguide scale 1 week after each bleaching session. Risk of TS was calculated from the VRS and analyzed by the McNemar test, while the level of TS was analyzed by the Mann-Whitney test. For the VAS, t-tests were used to compare data from the treatments at each assessment time. Data regarding color changes were subjected to Wilcoxon and Mann-Whitney tests (α=0.05). The preemptive administration of piroxicam did not affect the risk and level of TS compared to placebo, irrespective of the assessment time. The treatment sequence did not affect bleaching effectiveness. In conclusion, the administration of a single dose of piroxicam prior to in-office tooth bleaching was unable to significantly reduce the risk and level of TS.

Abstract Objective: To evaluate the sealing capacity and retention of apical barriers made with mineral trioxide aggregate (MTA) and Portland cement (PC). Material and Methods: Fifty-six bovine incisors were sectioned 8 mm above and 12 mm below the cement-enamel junction. The root canal was enlarged with a diamond drill to create a standard 2.5 mm diameter opening. Apical sheets of 5 mm thickness were placed using white MTA-Angelus or white PC. Fifteen samples of each material were exposed to human saliva in a dual chamber apparatus and casting was evaluated at 30 days. Samples without apical barriers and fully sealed samples were used as positive and negative controls (n = 3), respectively. Data were analyzed by Fisher's exact test (p<0.05) after 3 periods: 1 to 10 days (P1); days 11 to 20 (P2); and days 21 to 30 (P3). Then, three 1 mm thick sections were obtained at the apical level of other root samples of each material (n = 10) and the push-out test was performed Results: The leakage rates in P1, P2 and P3 were 60%, 73.3% and 100% for the MTA; and 73.3%, 86.7% and 100% for CP, with no significant difference between materials, regardless of the period analyzed. There were no significant differences between the bond strengths for both cements (p>0.05) Conclusion: Mineral trioxide aggregate and Portland cement apical barriers presented similar sealing ability and bond strength values.

Resumo Este estudo objetivou determinar o limiar de redução na espessura do compósito de cor da dentina necessário para resultar em mudanças de cor perceptíveis e aceitáveis em restaurações simuladas. Três sistemas de compósitos (Charisma Diamond, IPS Empress Direct e Filtek Z350 XT) foram avaliados utilizando corpos-de-prova cilíndricos construídos com cores de dentina e esmalte. A opacidade dos compósitos foi avaliada usando cilindros de 1,0 mm de espessura sobre fundo preto e branco. Uma cor inicial padrão foi estabelecida para cada sistema pela combinação de esmalte de 1,0 mm de espessura com 3,0 mm de cilindros de resina na cor de dentina sobre um fundo escuro (n = 9). Em seguida, foram calculadas as alterações de cor (∆E00) causadas por reduções sequenciais de 0,1 mm nos cilindros de resina na cor de dentina. Mudanças de opacidade em cilindros na cor de dentina e cilindros combinados de esmalte e dentina foram também avaliadas após cada redução de espessura. Regressão polinomial foi realizada com médias de ∆E00 em função da espessura dos cilindros na cor de dentina; e os limiares de aceitabilidade (∆E00 = 1,77) e perceptibilidade (∆E00 = 0,81) foram calculados. Regressões lineares também foram realizadas para ∆E00 em função da opacidade dos cilindros na cor de dentina e do par combinado de cilindros de esmalte-dentina. Com exceção da Charisma, os compósitos de esmalte apresentaram menor opacidade do que os de dentina. Alterações de cor perceptíveis e aceitáveis foram observadas quando os cilindros na cor de dentina foram mais finos que 2,0-2,4 mm e 1,1-1,4 mm, respectivamente. Nenhuma diferença entre os sistemas compostos foi observada. Em conclusão, reduções no compósito de dentina menor que 0,6 mm não produziu mudanças de cor perceptíveis, e mudanças de cor clinicamente significantes apenas foram observadas com reduções maiores que 1,6 mm.

Abstract This study determined the reduction threshold in thickness of the dentin shade composite necessary to result in perceptible and acceptable color changes on simulated restorations. Three composite systems (Charisma Diamond, IPS Empress Direct, and Filtek Z350 XT) were evaluated using cylinder-shaped specimens built-up with dentin and enamel shades. The opacity of the composites was assessed using 1.0 mm thick specimens over black and white backgrounds. A baseline color was established for each system by combining 1.0 mm thick enamel shade with 3.0 mm of dentin shade cylinders over a dark background (n = 9). Then, the color changes (∆E00) caused by sequential 0.1 mm reductions on dentin shade cylinders were calculated. Opacity changes on dentin shade cylinders and combined enamel-dentin pair cylinders were also assessed after each thickness reduction. Polynomial regression was performed with averages of ∆E00 as a function of thickness of dentin shade cylinders; and acceptability (∆E = 1.77) and perceptibility (∆E = 0.81) thresholds were calculated. Linear regressions were also performed for ∆E00 as function of opacity of dentin shade cylinders and combined enamel-dentin pair of cylinders. Except for Charisma, enamel shades presented the lowest opacity than dentin one. Perceptible and acceptable color changes were observed for dentin shade cylinders thinner than 2.0-2.4 mm and 1.1-1.4 mm, respectively, were used. No difference among the composite systems was observed. In conclusion, reductions on dentin shade composite lower than 0.6-mm did not yield perceptible color changes, and clinically significant color changes only were observed within reductions higher than 1.6-mm.

Resumo Este ensaio clínico controlado e randomizado avaliou o efeito da associação de procedimentos de clareamento caseiro e de consultório na sensibilidade dental (SD) e efetividade clareadora. Quarenta pacientes receberam uma sessão de clareamento de consultório com peróxido de hidrogênio a 38%. Em seguida, os pacientes foram aleatoriamente alocados para receberem uma segunda sessão de clareamento de consultório ou para usar uma moldeira com peróxido de carbamida a 10% por 7 dias consecutivos. O pior score de SD relatada durante ou após cada procedimento clareador foi mensurado usando uma escala verbal, e o risco a SD (escore diferente de 0) foi calculado. Mudança de cor foi mensurada 7 dias após cada sessão de clareamento de consultório (para paciente submetidos a apenas procedimentos de consultório) ou após o fim do clareamento de caseiro (para o protocolo combinado) e 6 meses após o último procedimento clareador para os dois protocolos de clareamento. A cor foi mensurada através de um espectrofotômetro e pelo uso das escalas Vita Clássica e Bleach guide. As análises estatísticas foram realizadas para verificar possíveis diferenças em relação aos desfechos e para analisar o efeito do momento da mensuração nas mudanças de cor. O protocolo clareador não afetou o risco e o nível máximo de SD relatado, independentemente do tempo de avaliação. Na avaliação de cor, o protocolo clareador também não afetou a cor final dos dentes. Como conclusão, após uma sessão de clareamento de consultório, não há diferença na efetividade clareadora e na SD em realizar uma segunda sessão de consultório ou associá-la com uma semana de clareamento caseiro.

Abstract This controlled randomized clinical trial evaluated the effect of associating at-home and in-office bleaching procedures on tooth sensitivity (TS) and bleaching effectiveness. Forty patients subjected to on session of in-office bleaching with 38% peroxide hydrogen. Subsequently, the patients were randomly allocated to receive a second session of in-office bleaching or to use a tray containing 10% carbamide peroxide delivered during 7 consecutive days. The worst TS score reported during or after each bleaching procedure was recorded using a verbal rating scale and TS risk (score different from 0) was calculated. Color changes were measured 7 days after each in-office session (for patients receiving in-office procedures only) or after the end of at-home bleaching (for the combined protocol), and 6 months after the last procedure for both bleaching protocols. Color was assessed by a spectrophotometer and by color match with the Vita Classical and Bleach guide scales. Statistical analyses were carried out to assess possible differences between the protocols regarding the outcomes and to analyze the effect of time of assessment on color changes. The bleaching protocol did not affect the risk for and the maximum level of TS reported, irrespective of the time of assessment. In the color evaluation, the bleaching protocol also did not affect the ultimate tooth color. In conclusion, after one in-office bleaching session, there was no difference in bleaching effectiveness and TS between performing a second in-office session and associating it with 1-week at-home bleaching.

Resumo Este estudo avaliou os efeitos do clareamento dental com peróxido de hidrogênio em alta concentração nas alterações do parâmetro de translucidez (PT) e cor da dentina e esmalte. A coroa de cinco molares humanos foi seccionada em quatro fatias paralelas à superfície vestibular. A dentina das fatias externas contendo esmalte vestibular/ lingual foi totalmente removida com ponta diamantada, sendo estas fatias usadas para verificar as alterações no esmalte. Alterações na dentina foram verificadas no centro das fatias internas. A cor das amostras foi mensurada sobre fundos preto e branco usando um espectrofotômetro (CieL*a*b) no início, permitindo calcular o PT pela diferença de cor medida sobre cada fundo. As amostras foram submetidas a três aplicações de 15 minutos de peróxido de hidrogênio a 35% seguido pelo seu armazenamento em água por uma semana. Após isto, as mensurações de cor foram repetidas em ambos os fundos. Mudanças de cor (∆L, ∆a, ∆b e ∆E) e translucidez (∆PT) foram calculadas e os dados analisados pelo Teste T (α = 0,05). A influência do tecido duro e do momento de avaliação em cada parâmetro de cor foi também analisado através de ANOVA de duas vias para medidas repetidas (α = 0,05). O clareamento dental resultou em maior luminosidade (∆L) para o esmalte, enquanto que nenhuma alteração neste parâmetro ocorreu para a dentina. Nenhuma diferença entre os tecidos duros dentais foi observada em relação aos outros parâmetros de cor e ∆E. Uma leve redução na PT foi observada apenas para o esmalte. Como conclusão, peróxido de hidrogênio a 35% causou similar alteração de cor e translucidez no esmalte e na dentina.

Abstract This study evaluated the effects of tooth bleaching with high-concentration of hydrogen peroxide on alterations of translucency parameter (TP) and color of dentin and enamel. The crown of five human molars was sectioned into four slices parallel to buccal surface. The dentin of external slices containing buccal/ lingual enamel was fully removed with diamond bur; while these slices were used to assess alterations on enamel. Alterations on dentin were assessed into the center of internal slices. The color of specimens was measured over white and black backgrounds using a spectrophotometer (CieL*a*b) at baseline, allowing to calculate the TP by difference between the color measured over each background. Specimens were submitted to three 15-min applications of 35% hydrogen peroxide followed by their storage in water for one-week. Afterwards, the color measurements were repeated at both backgrounds. Color (∆L, ∆a, ∆b and ∆E) and translucency (∆TP) changes were calculated and data individually analyzed by T-test (α = 0.05). Influence of hard tissue and assessment time on each color parameter was also analyzed by 2-way repeated measure ANOVA (α = 0.05). Tooth bleaching resulted in increased lightness for the enamel, whereas no alteration on this parameter occurred for dentin. No difference between the tooth hard tissues was observed regards the other color parameters and ∆E. A slightly reduction on TP was observed only for the enamel. In conclusion, 35% hydrogen peroxide caused similar color and translucency changes on dentin and enamel.

Abstract Objectives A single-blinded, randomized, parallel clinical trial evaluated the use of 37% carbamide peroxide (CP) on bleaching effectiveness and tooth sensitivity reported by patients undergoing in-office tooth bleaching, in comparison with the results of using 35% hydrogen peroxide. Material and Methods Forty patients were allocated to receive two sessions of in-office tooth bleaching using either 35% hydrogen peroxide (HP) or 37% CP. Each patient’s sensitivity level was evaluated during and up to 24 h after bleaching. The effectiveness of the bleaching procedures was evaluated with a spectrophotometer one week after each session and 30 days after the last session. The impact of tooth bleaching on the patients’ perceptions regarding smile changes, in addition to the bleaching procedures and their results, were also recorded. Absolute and relative sensitivity risks were calculated. Data on sensitivity level were analyzed using the Mann-Whitney or T-test, and data from the color evaluation were subjected to 2-way repeated measures ANOVA. Results The use of CP reduced the risk and level of tooth sensitivity to values close to zero, whereas the difference between the bleaching agents disappeared after 24 h. An increased bleaching effect was observed for HP, mainly due to an improved reduction of redness and yellowness. Participants perceived improved tooth bleaching for HP and reduced sensitivity for CP, but no differences regarding the comfort of the techniques were noted. Conclusions In our study, 37% CP resulted in reduced tooth sensitivity but decreased the tooth bleaching effectiveness. However, both bleaching agents resulted in high levels of patient satisfaction.

Abstract: Endodontic treatment is a common dental procedure used for treating teeth which the pulp tissue has become irreversibly inflamed or necrotic as a result of the carious process or dental trauma. This procedure which involves mechanical and chemical preparation of root canal may affect several mechanical and physical properties of the tooth structure. The endodontic treatment can also influence the longevity of the rehabilitation of endodontically treated teeth and biomechanics during the oral function. For restoring endodontically treated teeth several factor and clinical decisions should be observed. The decision of the fiberglass post usage and the restorative materials are related to several factors such as the quantity and quality of remaining dental structure, presence of ferrule, post cementation length and final coronal restoration. In this review, the authors will address the effect of the endodontic treatment procedures on canal shape and mechanical properties of a tooth, and also discuss the parameters and the biomechanical principles of root canal treated teeth.

Resumo O objetivo deste estudo foi avaliar o efeito da microabrasão prévia na alteração de cor dos dentes e na efetividade do clareamento dental. Oito molares hígidos foram mesio-distalmente seccionados e as metades foram aleatoriamente alocadas para receberem microabrasão do esmalte ou nenhuma abrasão (controle) em uma das faces (vestibular ou lingual), enquanto que a face remanescente recebeu o outro tratamento. A cor inicial dos dentes foi avaliada com um espectrofotômetro (sistema CieL*a*b). Após o procedimento de microabrasão, a cor do dente foi reavaliada. Em seguida, as amostras foram clareadas com peróxido de hidrogênio a 35% por duas sessões com uma semana de intervalo. A cor foi reavaliada 7 dias após cada sessão e 30 dias após a segunda sessão. O efeito da microabrasão do esmalte na mudança de cor foi avaliado pelo teste T pareado. Deltas L*, a*, b* e E foram calculados e os dados submetidos a ANOVA de duas vias para medidas repetidas e teste de Tukey. Teste T pareado também foi usado para verificar possíveis diferenças na cor final alcançada com o clareamento dental. A microabrasão do esmalte reduziu a luminosidade e aumentou a tonalidade vermelha nas amostras. Amostras submetidas a microabrasão apresentaram maiores valores de ∆L* que o controle após cada procedimento clareador, e maior ∆a* após a 2ª sessão de clareamento. Entretanto, a microabrasão prévia do esmalte não afetou os valores finais dos parâmetros de cor. Apesar da microabraão do esmalte ter alterado a cor dental, este procedimento não afetou os resultados finais alcançados com o clareamento dental usando alta concentração de peróxido de hidrogênio.

Abstract The aim of the present study was to evaluate the effect of prior microabrasion on the teeth color change and tooth bleaching effectiveness. Eight sound molars were mesio-distally sectioned and the halves were randomly allocated to receive enamel microabrasion or non-abrasion (control) in one of surfaces (buccal or lingual), while the remaining surface received the other treatment. The tooth color on baseline was evaluated by spectrophotometer (CieL*a*b system). After the microabrasion procedure, the tooth color was measured again. Following, the specimens were bleached with 35% hydrogen peroxide for two sessions with one-week interval. The color was re-evaluated 7 days after each section and 30 days after the second session. The effect of enamel microabrasion on color changes was evaluated by paired T-test. Deltas L*, a*, b*, and E were calculated and data submitted to 2-way repeated measure ANOVA followed by Tukey`s test. Paired T-test was also used to assess possible differences on the ultimate color achieved after tooth bleaching. Enamel microabrasion reduced the lightness and increased the redness of specimens. Specimens that received microabrasion presented higher values of ∆L* than control after each bleaching procedure; and higher ∆a* after the 2nd bleaching session. However, the prior enamel microabrasion did not affect the ultimate values of color parameters. Despite enamel microabrasion have modified the tooth color, this procedure did not affect the ultimate results achieved with tooth bleaching using a high-concentrated hydrogen peroxide.

Abstract Polymerization shrinkage stress of resin-based materials have been related to several unwanted clinical consequences, such as enamel crack propagation, cusp deflection, marginal and internal gaps, and decreased bond strength. Despite the absence of strong evidence relating polymerization shrinkage to secondary caries or fracture of posterior teeth, shrinkage stress has been associated with post-operative sensitivity and marginal stain. The latter is often erroneously used as a criterion for replacement of composite restorations. Therefore, an indirect correlation can emerge between shrinkage stress and the longevity of composite restorations or resin-bonded ceramic restorations. The relationship between shrinkage and stress can be best studied in laboratory experiments and a combination of various methodologies. The objective of this review article is to discuss the concept and consequences of polymerization shrinkage and shrinkage stress of composite resins and resin cements. Literature relating to polymerization shrinkage and shrinkage stress generation, research methodologies, and contributing factors are selected and reviewed. Clinical techniques that could reduce shrinkage stress and new developments on low-shrink dental materials are also discussed.

Resumo A relação entre o uso de aparelhos ortodônticos fixos e desmineralização do esmalte é bem estabelecida. Diferentes abordagens preventivas têm sido sugeridas para este problema, mas ainda permanece controverso qual é o melhor. O objetivo deste estudo foi realizar uma revisão sistemática de ensaios clínicos que investigaram a efetividade de materiais contendo fluoretos para cimentação de bráquetes ou cobrindo a interface de união buscando inibir o desenvolvimento e progressão de lesões de mancha branca. A hipótese nula foi que materiais fluoretados não afetam a incidência de lesões de mancha branca em volta de bráquetes. Uma busca no MEDLINE foi conduzida para ensaios clínicos controlados avaliando o desenvolvimento de lesões de mancha branca em pacientes usando aparelhos ortodônticos fixos, seguido por meta-análise comparando os resultados de pacientes em que materiais usando fluoretos foram utilizados (grupo experimental) com aqueles em que tais materiais não foram usados. O risco relativo agrupado de desenvolvimento de lesões de mancha branca para o grupo experimental foi 0,42 (95% de intervalo de confiança: 0,25 a 0,72); enquanto que, quando materiais liberando fluoretos foram utilizados, o paciente teve 58% menos risco de desenvolver lesões de mancha branca. Em relação à extensão das lesões de mancha branca, a diferença média agrupada entre os grupos experimental e controle não foi estatisticamente significante (-0,12; 95% de intervalo de confiança: -0,29 a 0,04). Em conclusão, os resultados da presente revisão sistemática sugerem que materiais que liberam fluoretos podem reduzir o risco de lesões de mancha branca em volta de bráquetes. Entretanto, quando lesões de mancha branca já ocorreram, não há evidência que materiais que liberam fluoretos reduzem a extensão da lesão.

Abstract The relation between orthodontic fixed appliances use and enamel demineralization is well established. Different preventive approaches have been suggested to this problem, but controversy remains about which is the best. The aim of this study was to perform a systematic review of clinical trials that investigated the effectiveness of materials containing fluorides to lute brackets or cover the bonding interface in order to inhibit the development and progression of white spot lesions. The null hypothesis was that fluoride materials do not affect the incidence of white spot lesions around brackets. A MEDLINE search was conducted for randomized clinical trials evaluating the development of white spot lesions in patients using fixed orthodontic appliances, followed by meta-analysis comparing the results for patients for whom dental materials containing fluorides were used (experimental group) to those for whom these materials were not used (control group). The pooled relative risk of developing white spot lesions for the experimental group was 0.42 (95% confidence interval: 0.25 to 0.72); hence, when fluoride-releasing materials are used, the patient has 58% less risk of white spot lesion development. Regarding white spot lesion extent, the pooled mean difference between the experimental and control groups was not statistically significant (-0.12; 95% confidence interval: -0.29 to 0.04). In conclusion, the results of the present systematic review suggest that fluoride-releasing materials can reduce the risk of white spot lesions around brackets. However, when white spot lesions had already occurred, there is no evidence that fluoride-releasing materials reduce the extent of these lesions.

Abstract This study evaluated the effect of mineral trioxide aggregate (MTA) on the retention of fiber posts in repaired root canal perforations. Ten-millimeter post spaces were prepared in 60 endodontically treated bovine incisors. Root perforations were created in half of the root canals in the cervical area prior to being filled with white MTA-Angelus. Fiber posts were luted into the root canals with two self-adhesive (RelyX Unicem or Set) or self-etching (Panavia F) resin cements. The posts were submitted to a pull-out test, and the data were submitted to two-way ANOVA and Tukey’s post hoc tests (α = 0.05). The fiber posts exhibited reduced retention in MTA-repaired root canal perforations, regardless of the type of resin cement that was used (p < 0.001). Self-adhesive resin cements provided higher bond strength values than Panavia F, while no difference was observed between RelyX Unicem and Set (p > 0.05). The presence of MTA in repaired root perforations negatively affected post retention. In addition, self-adhesive cements seemed to be the best option to lute fiber posts within a root canal in these cases.