Mechanical properties of the bond interface associated with ND: YAG laser / Propriedades mecanicas da interface adesiva associada ao laser de ND: YAG

This study evaluated the hardness and modulus of elasticity of the dentin bond interface using total-etch(Single Bond /SB) and self-etch (Clearfil SE Bond/CSEB) adhesives associated with Nd:YAG Laser irradiation through the unpolymerized adhesives. Material and Methods: The occlusal surfaces of 12 human third molars were ground until superficial dentin was exposed. A standardized circular cavity was performed on the occlusal surface. Specimens were sectioned in the mesio-distal direction, and the 24 hemi-crowns were divided into four groups: Group SB/Control - SB + polymerization; GroupSB/Laser - SB + Nd:YAG laser (174.16J/cm2/60s/noncontact)+ polymerization; Group CSEB/Control – CSEB +polymerization; Group CSEB/Laser - CSEB + Nd:YAG laser(174.16J/cm2/cm2/60s/non-contact) + polymerization. Composite were placed in the cavities and polymerized. The specimens were immersed in distilled water and stored in an oven at 37ºC for 24h and then submitted to nanoindentation in a Nano Indenter® XP appliance. Results: The results were submitted to ANOVA, Tukey’stest and Student’s-t test (p < 0.05). Conclusion: It was concluded that the application of the Nd:YAG laser inboth adhesive systems did not changed the hybrid layer hardness; however, it increases the modulus of elasticityin the hybrid layer for both adhesives tested and it may bepreserves the integrity of the adhesive interface and its durability. Clinical relevance: The application of Nd:YA Glaser prior to photopolymerization of adhesive systems can increase the modulus of elasticity in the hybrid layerand may contribute to stress distribution in the adhesive interface during the polymerization preserving the integrity of the adhesive interface and its durability...

este estudo avaliou a dureza e o módulo de elasticidade da interface adesiva a dentina usando adesivo convencional (Sinngle Bond /SB) e adesivo autocondicionante (Clearfil SE Bond/CSEB) associados com irradiação do Laser Nd:YAH sobre os adesivos não polimerizados. Material e Métodos: As superfícies oclusais de 12 terceiros molares humanos foram desgastadas ate exposição de dentina superficial plana. Cavidades circulares padronizadas foram realizadas na superficie oclusal. Os espécimes foram seccionados no sentido mesio-distal, e as 24 hemicoroas foram divididas em quatro grupos: Grupo SB/Controle - SB + fotopolimerização; Grupo SB/Laser- SB + Laser Nd:YAG (174,16J/cm2/60s/não-contato)+ fotopolimerização; Grupo CSEB/Controle – CSEB +fotopolimerização; Grupo CSEB/Laser - CSEB + LaserNd:YAG (174.16J/cm2/cm2/60s/ não-contato) +fotopolimerização. Restaurações de resina composta foram realizadas nas cavidades e fotopolimerizadas. Os espécimes foram armazenados em água destilada a 37 ºC por 24 h e submetidas a nanoindentação no aparelho Nano Indenter® XP. Resultados: Os resultados foram submetidos ao ANOVA, seguidos dos testes de Tukey e T-Student (p < 0,05). Conclusão:Foi concluído que a aplicação do Laser de Nd:YAG nos adesivos não alterou a dureza da camada híbrida;entretanto, aumentou o módulo de elasticidade de ambos os adesivos testados e talvez preserve a integridade da interface adesiva e sua durabilidade...

New trends in dentin bonding: treatment with Chlorhexidine, Hyaluronic acid, vitamin C and green tea / Novas tendências em adesão dentinária: tratamento com clorexidina, ácido hialurônico, vitamina C e chá verde

Objetivo: O objetivo deste estudo foi avaliar a resistência de união dentinária tratada com clorexidina, ácido hialurônico, vitamina C e chá verde. Material e Métodos: As raízes de 50 dentes bovinos foram removidas e a superfície de dentina vestibular exposta. Após o condicionamento ácido, os espécimes foram divididos em 5 grupos (n = 10), de acordo com as estratégias adesivas na dentina: CO - dentina não tratada; CHX – tratamento com clorexidina 2% por 30 s; HA - tratamento com ácido hialurônico 1% por 30 s; VC - tratamento com vitamina C 10% por 30 s; GT – tratamento com extrato de chá verde 1% por 30 s. Sistema adesivo Adper Single Bond II foi aplicado segundo recomendações do fabricante. Os espécimes foram restaurados com uma camada de 4 mm de espessura de resina composta, que foi polimerizada por 40 s. As amostras foram armazenadas em água destilada a 37 ° C durante 24 h, e seccionada em palitos de 1 x 1 mm2 contendo a interface adesiva. Teste de microtração foi realizado com uma máquina de ensaios universal a uma velocidade de 0,5 mm/min. Resultados: Os resultados foram analisados com teste de variância ANOVA um-fator e testes de múltipla comparação de Tukey (p < 0,05). Grupo GT apresentou os maiores valores de resistência de união (29,4 ± 3,1) a, mas sem diferença significativa em relação aos demais grupos experimentais HA (26,7 ± 3,1) ab, CHX (25,4 ± 2,6) ab e VC (22,4 ± 6,0) b. Resistência de união dos grupos experimentais não foi significativamente diferente do grupo CO. Conclusão: a resistência de união imediata foi mantida mesmo após os diferentes tratamentos dentinários.

Objective: The aim of this study was to evaluate the bond strength of dentin treated with chlorhexidine, hyaluronic acid, vitamin C and green tea. Material and Methods: The roots of 50 bovine teeth were removed and buccal coronal dentin was exposed. After acidetching, the specimens were divided into 5 groups (n= 10), according to the dentin treatment strategy: CO -untreated dentin; CHX - treated with 2 wt% chlorhexidine for 30 s; HA - treated with 1 wt% hyaluronic acid for 30s; VC - treated with 10 wt% vitamin C for 30 s; GT - treated a 1% green tea extract for 30 s. Adper Single Bond was then applied to the treated according to the manufacturer’s recommendations. The specimens were restored with a 4 mm thick layer of the resin composite, which was polymerized for 40 s. The specimens were stored in distilled water at 37°C for 24 h and sectioned into 1 x 1 mm2 sticks containing the adhesive interface. Microtensile bond strength testing was performed with a universal testing machine at a cross-head speed of 1.0 mm/min. Results: The results were analyzed with onefactor ANOVA and Tukey’s multiple comparison tests. GT group presented the highest values bond strength (29.4 ± 3.1) a, but no significant difference compared to the other experimental groups HA (26.7 ± 3.1) ab, CHX (25.4 ±2.6) ab and VC (22.4 ± 6.0) b. Bond strengths of experimental groups were not significantly different from the CO. Conclusion: Immediate bond strength was preserved after acid-etched dentin was treated.

Surface roughness of indirect composites using different polishing systems / Rugosidade superficial de resinas compostas indiretas utilizando diferentes sistemas de polimento

Objective: The aim of this study was to evaluate the surface roughness of indirect composites after polishing with aluminum oxide (Al2O3) discs. Material and Methods: One-hundred and eighty specimens were confectioned with 6 indirect composites using a prefabricated matrix, resulting in six groups (n-30): Group SO - Solidex, Group SI - Signum, Group SF - Sinfony, Group OP - Opallis; Group RE - Resilab, Group EP - Epricord, Group AD - Adoro. Each group was divided into three subgroups according to the polishing (n-10): Subgroup C (Control) – without polishing (polyester strip); Subgroup S – polishing with Sof-Lex discs; Subgroup T - polishing with TDV discs. The surface roughness was measured with a profilometer. Results: The results were analyzed by ANOVA and Tukey tests (5%), resulting in p = 0.00. The mean values (±standard-deviation) measured in Ra (µm) for each Group/Subgroup were: RE/C - 0.14 (± 0.14) a; EP/C - 0.18 (± 0.46) ab; SO/C - 0.24 (± 0.22) abc; SF/S - 0.24 (± 0.17) abc; SF/C - 0.26 (± 2.54)abc; SI/C - 0.30 (± 0.34)abcd; SO/T - 0.33(± 0.42) abcd; AD/S - 0.34(± 0.88)abcd; AD/C - 0.37(± 0.60)ab; SI/S - 0.37(± 1.39)bcd; SO/S - 0.43(± 0.26) cd; EP/S – 0.44 (± 1.02) cd; RE/S - 0.54(±2.02) de; SI/T - 0.65(± 0.88)ef; RE/T - 0.83 (± 0.54) fg; SF/T - 0.85 (± 0.21) fg; AD/T - 0.88 (± 1.74) fg; EP/T - 0.91(± 0.89) g. Conclusion: It is concluded that polyester strip resulted in significantly lowest surface roughness; polishing with TDV discs resulted in significantly higher surface roughness compared to Sof-Lex discs and that the surface roughness results depend on the composite tested

Objetivo: O objetivo este estudo foi avaliar a rugosidade superficial de resinas compostas indiretas após polimento com discos de óxido de alumínio (Al2O3). Material e Métodos: Foram confeccionados 180 espécimes de 6 resinas compostas indiretas utilizando uma matriz pré-fabricada, resultando em 6 grupos (n - 30): Grupo SO - Solidex, Grupo SI - Signum, Grupo SF - Sinfony, Grupo OP - Opallis; Grupo RE - Resilab, Grupo EP - Epricord, Grupo AD - Adoro. Cada grupo foi dividido em três subgrupos, de acordo com a técnica de polimento: Subgrupo C - não foi realizado polimento (tira de poliéster); Subgrupo S: polimento com discos Sof-Lex; Subgrupo T: polimento com discos TDV. A rugosidade superficial foi mensurada com um rugosímetro. Resultados: Os resultados foram analisados pelos testes estatísticos de ANOVA e Tukey (5%), obtendo-se p = 0,00. Os valores de média (± desvio-padrão) medidos em Ra (μm) para cada Grupo/ Subgrupo foram: RE/C – 0,14 (± 0,14) a; EP/C – 0,18(± 0,46) ab; SO/C – 0,24 (± 0,22)abc; SF/S – 0,24 (± 0,17) abc; SF/C – 0,26 (± 2,54) abc; SI/C – 0,30 (± 0,34) abcd; SO/T – 0,33 (± 0,42) abcd; AD/S – 0,34 (± 0,88) abcd; AD/C – 0,37 (± 0,60) ab; SI/S – 0,37(± 1,39) bcd; SO/S – 0,43 (± 0,26) cd; EP/S – 0,44 (± 1,02) cd; RE/S – 0,54 (±2,02)de; SI/T – 0,65 (± 0,88) ef; RE/T – 0,83 (± 0,54) fg; SF/T – 0,85 (± 0,21) fg; AD/T - 0,88 (± 1,74 ) fg; EP/T - 0,91(± 0,89) g. Conclusão: Pode-se concluir que a tira de poliéster resultou na menor rugosidade superficial; o polimento com discos TDV apresentou média significantemente maior de rugosidade em relação ao polimento com discos Sof-Lex e que o resultado de lisura superficial depende da resina composta testada.

A comparison of methods used to determine chewing side preference in deciduous, mixed and permanent dentitions / Comparação dos métodos usados para determinar o lado preferencial mastigatório nas dentições decídua, mista e permanente

Objective: This study determined whether ‘chewing side preference’ (CSP) is correlated to ‘chewing side preference during the first chewing cycle’ (CSP1ºC) in the deciduous, mixed and permanent dentitions. Methods: Three-hundred subjects were divided in 3 groups: Group 1 – 100 children 3-5 years old, primary dentition; Group 2 – 100 children 6-12 years old, mixed dentition; Group 3 – 100 subjects 18-47 years old, permanent dentition. CSP was determined using a method developed by McDonnell et al. Subjects were given a piece of gum and the position of the chewing gum was recorded 7 times as right or left. Subjects were classified as ‘observed preferred chewing side’ (OPCS) when they performed 5/7, 6/7 or 7/7 strokes on the same side. OPCS corresponded to the CSP. CSP1ºC was determined using a method developed by Hoogmartens and Caubergh (1987). Subjects were given five pieces of gum and five pieces of bread and the position of the chewing gum at first chewing cycle was recorded as right or left. For each subject, an index (I) was performed. Chi-square (X2) and phi correlation (r) tests were used to investigate significant correlations between CSP and CSP1ºC. Results: There was a strong positive and significant correlation between CSP and CSP1ºC for primary dentition (p= 0.000; r = 0.82), for mixed dentition (p = 0.000; r = 0.81) and a very strong positive and significant correlation for permanent dentition (p = 0.000; r = 0.90). Conclusion: CSP can be significantly correlated to CSP1ºC for primary dentition, mixed dentition and permanent dentition, and these are strong positive relationships for primary and mixed dentitions and very strong positive relationship for permanent dentition.

Objetivo: Este estudo determinou se o ‘lado preferencial mastigatório’ (LPM) é correlacionado com o ‘lado preferencial no primeiro ciclo mastigatório’ (LP1ºCM) nas dentições decídua, mista e permanente. Métodos: Trezentos indivíduos foram divididos em 3 grupos: Grupo 1 – 100 crianças de 3-5 anos, dentição primária; Grupo 2 – 100 crianças de 6-12 anos, dentição mista; Grupo 3 – 100 indivíduos de 18-47 anos, dentição permanente. O LPM foi determinado usando o método desenvolvido por McDonnell et al. Indivíduos recebiam um pedaço de goma de mascar e, durante a mastigação, foi anotado o lado (esquerdo ou direito) por 7 vezes. Os indivíduos foram classificados como ‘lado preferencial mastigatório observacional’ (LPMO) quando realizavam 5/7, 6/7 ou 7/7 mordidas do mesmo lado, correspondendo, portando, ao LPM. O LP1ºCM foi determinado usando o método desenvolvido por Hoogmartens e Caubergh. Os indivíduos recebiam 5 pedaços de goma de mascar e 5 pedaços de torrada, e a posição da primeira mordida foi anotada (esquerdo ou direito). Cada indivíduo recebeu um index (I). Os testes Qui-quadrado (X2) e Correlação de Phi (r) foram utilizados para avaliar as correlações significantes entre LPM e LP1ºCM. Resultados: Houve forte e positiva correlação significante entre LPM e LP1ºCM para as dentições decíduas (p = 0,000; r = 0,82), para dentição mista (p = 0,000; r = 0,81) e muito forte e positiva para dentição permanente (p = 0,000; r = 0,90). Conclusão: LPM pode ser significantemente correlacionado com LP1ºCM para todas as dentições, e essas correlações são fortes e positivas para as dentições decídua e mista e muito forte e positiva para a dentição permanente.

Absence or weak correlation between chewing side preference and lateralities in primary, mixed and permanent dentition.

OBJECTIVES: To determine whether chewing side preference (CSP) is correlated to lateralities (handedness, footedness, eyedness and earedness) in primary, mixed and permanent dentitions. DESIGN: Three-hundred subjects were divided into 3 groups: Group 1--100 children 3-5 years old, primary dentition; Group 2--100 children 6-12 years old, mixed dentition; Group 3--100 subjects 18-47 years old, permanent dentition. CSP was determined using a method developed by Mc Donnell et al. Subjects were given a piece of gum and the position of the chewing gum was recorded 7 times as right or left. Subjects were classified as 'observed preferred chewing side' (OPCS) when they performed 5/7, 6/7 or 7/7 strokes on the same side. OPCS corresponded to the CSP. Laterality tests were performed for handedness, footedness, eyedness and earedness tasks. The Chi-square (χ(2)) and phi correlation (r) tests were used to investigate significant correlations between CSP and sidedness. RESULTS: There was a significant correlation between chewing and earedness (p=0.00), although there was weak positive correlation (r=0.30) for primary dentition. There were significant correlations between chewing and handedness (p=0.02; r=0.25) and chewing and footedness (p=0.02; r=0.26), however, there were weak positive correlations for mixed dentition; there were significant correlations between chewing and handedness (p=0.02; r=0.26); chewing and footedness (p=0.00; r=0.33) and chewing and earedness (p=0.01; r=0.29); however, there were weak positive correlations for permanent dentition. CONCLUSION: It may be concluded that CSP can be significantly correlated with: earedness for primary dentition; handedness and footedness for mixed dentition; handedness, footedness and earedness for permanent dentition, but these are weak positive relationships. Future work on larger samples of left- and right-sided individuals is required to validate the findings.

The effectiveness of low-intensity red laser for activating a bleaching gel and its effect in temperature of the bleaching gel and the dental pulp.

STATEMENT OF THE PROBLEM: The effectiveness of low-intensity red laser for activating a bleaching gel and its effect in pulp temperature was not investigated in dental literature. PURPOSE: The objective of this study was to assess the effectiveness of low-intensity red laser for activating a bleaching gel, as well as its effect in temperature of the bleaching gel and the dental pulp. MATERIALS AND METHODS: Forty extracted bovine teeth were immersed in a solution of coffee 14 days for darkening. The initial colors were recorded by spectrophotometric analysis. The specimens were randomly distributed into two groups (N = 20): the control, which did not receive light and the experimental group that received light from an appliance fitted with three red light-emitting laser diodes (λ = 660 nm). A green-colored, 35% H(2) O(2) -based bleaching gel was applied for 30 minutes, and changed three times. After bleaching, the colors were again measured to obtain the L*a*b* values. Color variation was calculated (ΔE) and the data submitted to the non-paired t-test (5%). To assess temperature, 10 human incisors were prepared, in which one thermocouple was placed on the bleaching gel applied on the surface of the teeth and another inside the pulp chamber. RESULTS: There was a significant difference between the groups (p = 0.016), and the experimental group presented a significantly higher mean variation (7.21 ± 2.76) in comparison with the control group (5.37 ± 1.76). There was an increase in pulp temperature, but it was not sufficient to cause damage to the pulp. CONCLUSION: Bleaching gel activation with low-intensity red laser was capable of increasing the effectiveness of bleaching treatment and did not increase pulp temperature to levels deleterious to the pulp.

Influence of application methods of self-etching adhesive systems on adhesive bond strength to dentin.

PURPOSE: To assess the influence of variations in the application technique of self-etching adhesive systems on the shear bond strength to dentin. MATERIALS AND METHODS: The buccal surface of 255 extracted bovine teeth was ground to expose a flat dentin surface; the teeth were divided into four experimental groups. The self-etching adhesive systems One Up Bond F Plus, Clearfil SE Bond, Xeno III, and FuturaBond NR were used, and the etch-and-rinse adhesive Adper Single Bond 2 was used as the control group. One or two layers of the self-etching systems were actively or passively applied. Cylinders of composite resin were bonded to dentin, and after 24 h, specimens were shear tested in a universal testing machine at a crosshead speed of 1 mm/min. The data were submitted to two-way ANOVA, Dunnett's and Tukey's test (5%). RESULTS: There were significant differences for the factors adhesive type, application method, and their interaction. All adhesive systems showed significant differences. The active application of two layers of self-etching bonding systems resulted in a significantly higher mean than the passive application method. CONCLUSION: The active application of self-etching adhesive systems tends to increase the dentin shear bond strength, and the influence of the application method depends on the tested adhesive.

Prevalence of chewing side preference in the deciduous, mixed and permanent dentitions.

AIM: This study evaluated the prevalence of the chewing side preference (CSP) in the deciduous, mixed and permanent dentitions. MATERIALS AND METHODS: Three-hundred subjects were divided in three groups (n = 100): Group 1 - children with deciduous dentition; group 2-children with mixed dentition; group 3 - subjects with permanent dentition. The CSP was determined using a direct method (visual observation) developed by McDonnell et al. (2004). Descriptive statistic was used to observe the prevalence of CSP. The Pearson's Chi-square was used to investigate signicant associations between gender, presence of CSP and preferred side (right/left). RESULTS AND CONCLUSION: Eighty-seven percent of group 1 had a CSP. Eighty-two percent of group 2 had a CSP. Seventy-six percent of group 3 had a CSP. There was no statistically significant association between presence of CSP and gender in all groups. There was no statistically significant association between preferred side (right/left) and gender in all groups. CLINICAL SIGNIFICANCE: There is a higher prevalence of subjects in deciduous, mixed and permanent dentition that presented chewing side preference. The early diagnosis of the presence of chewing side preference can prevent the unilateral chewing pattern with prophylactic therapy applied to the first teeth (deciduous).

A comparative study of the physical properties of conventional and Grander-modified adhesive systems / Estudo comparativo das propriedades físicas de sistemas adesivos convencional e Grander-modificado

PURPOSE: The objective of this study was to evaluate the influence of the Grander technology in reducing the surface tension and contact angle of a self-etch adhesive system. METHODS: Distilled water and Xeno III self-etch adhesive system (Dentsply) were modified by physical contact with the Flexible unit Grander system to revitalize water, for 48 hours, resulting in four groups: Group 1 - Xeno III under normal conditions; Group 2 - Xeno III modified by Grander; Group 3 - distilled water under normal conditions; Group 4 - distilled water system modified by the Grander system;. Surface tension and contact angle (dentin substrate and titanium plate) of the adhesive system and water in normal and Grander-modified conditions was measured with a goniometer. Data were analyzed by ANOVA and Tukey test (5%). RESULTS: Grander technology reduced the surface tension of water but not of the adhesive system Xeno III. The contact angle property of the adhesive ystem was not affected. CONCLUSION: Grander technology did not interfere with the surface tension and contact angle physical properties of the Xeno III self-etch adhesive system.

OBJETIVO: Esta pesquisa verificou os efeitos da tecnologia Grander na alteração da tensão superficial e ângulo de contato de um sistema adesivo autocondicionante. METODOLOGIA: O sistema adesivo autocondicionante Xeno III (Dentsply) e a água destilada foram modificados pelo contato físico com a unidade flexible do sistema Grander para revitalização de águas por 48 horas, resultando em 4 grupos: Grupo 1 - sistema adesivo Xeno III em condições de normalidade; Grupo 2 - sistema adesivo Xeno III modificado pelo sistema Grander; Grupo 3 - água destilada em condições de normalidade; Grupo 4 - água destilada modificada pelo sistema Grander. A tensão superficial dos líquidos foi verificada em goniômetro utilizando cinco medidas para cada gota de líquido. O ângulo de contato foi medido com o goniômetro sobre os substratos placa de titânio e dentes bovinos. Os dados foram submetidos aos testes ANOVA e Tukey (5%). RESULTADOS: Houve redução significativa da tensão superficial da água com a modificação pelo sistema Grander. Não houve redução da tensão superficial e ângulo de contato para o sistema adesivo Xeno III. CONCLUSÃO: A tecnologia Grander não interferiu com a tensão superficial e o ângulo de contato para o sistema adesivo Xeno III.