Dentin Bonding: SEM Comparison of the Resin-Dentin Interface in Primary and Permanent Teeth

Previous studies have suggested minor differences between primary and permanent teeth in terms of dentin composition and morphology. Other reports indicated lower bond strengths of resin composites to dentin of primary teeth compared with dentin of permanent teeth; however, no information is available regarding differences in the micromorphology of the resin-dentin interface that may explain these lower bond strengths. Therefore, the purpose of the present study was to compare primary and permanent teeth in terms of the thickness of the hybrid layer developed with two bonding systems. Our hypothesis was that bonding differences previously reported between primary and permanent dentin would be reflected in hybrid layer differences observable in SEM analyses. Twenty human extracted and non-carious teeth were divided into 4 groups: 5 primary and 5 permanent teeth restored with All-Bond 2/Bisfil P system; and 5 primary and 5 permanent teeth restored with Scotchbond Multi-Purpose/ZlOO. The sample area available on each tooth was divided for the two dentin conditioning times (7 and 15 sec). Measurements of hybrid layer thickness were performed by means of SEM at xl3,000. The results of this study indicated that the hybrid layer produced is significantly thicker in primary than in permanent teeth (p = 0.0001), suggesting that primary tooth dentin is more reactive to acid conditioning. No difference was observed in the hybrid layers produced by the two adhesive systems (p = 0.7920). The increased thickness of the hybrid layer in primary teeth (25 to 30%) and the subsequent lack of complete penetration of adhesive resin into previously demineralized dentin may contribute to the lower bond strengths to primary dentin reported in the literature. If a narrower hybrid layer more uniformly infused with resin is the goal of dentin bonding, it is concluded that a differentiated protocol for bonding to primary dentin (with shorter time for dentin conditioning) can be used as a means to reproduce the hybrid layer thickness seen in permanent teeth.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67017/2/10.1177_00220345960750061101.pd

Evaluation of the permeability of the furcation area of deciduous molars conditioned with Er:YAG laser and cyanoacrylate Avaliação da permeabilidade da região da furca de molares decíduos condicionada com laser de Er:YAG e cianoacrilatos

The purpose of this study was to evaluate in vitro the dentin permeability of the deciduous pulp chamber floor after employing 2-octyl cyanoacrylate and Er:YAG laser. Twenty four deciduous molars were used, divided into four groups. After chemical-surgical preparation each group received a different treatment: Group 1 - control, without treatment; Group 2 - the floor of the pulp chamber was covered with a fine layer of 2-octyl cyanoacrylate; Group 3 - the floor of the pulp chamber was irradiated with Er:YAG laser (250 mJ, 10 Hz for 30 seconds, 80 J of energy and 320 pulses), and covered with a fine layer of 2-octyl cyanoacrylate; and Group 4 - the floor of the pulp chamber was irradiated with Er:YAG laser set at the parameters already described. After that the specimens received application of 0.5% methylene blue, for 15 minutes. The teeth were cut, photographed, and the digitalized images were analyzed using the ImageLab program. The results obtained were submitted to statistical analysis. Group 4 (Er:YAG) presented the largest averages in percentage of dye penetration area (19.5%), followed by Group 1 (11.1%), Group 3 (1.4%) and Group 2 (0.2%). The experimental model allowed to conclude that the specimens conditioned with 2-octyl cyanoacrylate (Group 2) and Er:YAG laser associated to 2-octyl cyanoacrylate (Group 3) presented a decrease in permeability, and the specimens treated with Er:YAG laser (Group 4) presented an increase in permeability of the analyzed area.<br>A proposta do presente experimento foi avaliar in vitro a permeabilidade da dentina no assoalho da câmara pulpar de dentes decíduos com o emprego do 2-octil cianoacrilato e laser de Er:YAG. Foram empregados 24 molares decíduos, divididos em quatro grupos. Após preparo químico-cirúrgico, cada grupo recebeu um tratamento diferente: Grupo 1 - controle, sem tratamento; Grupo 2 - o assoalho da câmara pulpar foi coberto com uma fina camada de 2-octil cianoacrilato; Grupo 3 - o assoalho da câmara pulpar foi irradiado com laser de Er:YAG (250 mJ, 10 Hz por 30 segundos, energia total de 80 J e 320 pulsos), e coberto com uma fina camada de 2-octil cianoacrilato; e Grupo 4 - o assoalho da câmara pulpar foi irradiado com laser de Er:YAG, nos parâmetros já descritos. Em seguida, os espécimes receberam aplicação do corante azul de metileno a 0,5%, por 15 minutos. Todos os espécimes foram cortados no sentido mésio-distal, foi realizada a leitura das imagens digitalizadas no programa ImageLab e os resultados obtidos foram submetidos à análise estatística. As amostras do Grupo 4 (Er:YAG) apresentaram as maiores médias em porcentagem de área corada (19,5%), seguidas das do Grupo 1 (11,1%), Grupo 3 (1,4%) e Grupo 2 (0,2%), respectivamente. O modelo experimental empregado permitiu concluir que os espécimes condicionados com 2-octil cianoacrilato (Grupo 2) e laser de Er:YAG associado ao 2-octil cianoacrilato (Grupo 3) apresentaram redução da permeabilidade, e os espécimes tratados com laser de Er:YAG (Grupo 4) apresentaram aumento da permeabilidade da área analisada

Prognostic implication of the absolute lymphocyte to absolute monocyte count ratio in patients with classical hodgkin lymphoma treated with doxorubicin, bleomycin, vinblastine, and dacarbazine or equivalent regimens

Low absolute lymphocyte count (ALC) to absolute monocyte count (AMC) ratio (ALC/AMC) is an independent prognostic factor in Hodgkin lymphoma (HL), but different cutoffs (1.1, 1.5, and 2.9) have been applied. We aimed to validate the prognostic significance of ALC/AMC in 537 homogenously treated (doxorubicin, bleomycin, vinblastine, and dacarbazine or equivalents 6 radiotherapy) classical HL patients at various cutoffs. The median ALC/AMC was 2.24 (0.44-20.50). The median AMC was 0.653 X 109/L (0.050-2.070). Lower ALC/ AMC was associated with established markers of adverse prognosis. In total, 477 (89%), 418 (78%), and 189 (35%) patients had an ALC/AMC ratio of $1.1,$1.5, and $2.9; respectively; 20$0.9 X 109/L).Ten-year time to progression (TTP) was 77% versus 55% for patients with ALC/AMC 1.1 and &lt;1.1 (p =.0002), 76% versus 68% for ALC/AMC 1.5 and &amp;lt;1.5 (p =.049), 77% versus 73% for ALC/AMC 2.9 and &lt;2.9 (p =.35), and 79% versus 70% for ALC/AMC 2.24 and &amp;lt;2.24 (p =.08), respectively. In stages IA/IIA and in patients $60 years old, ALC/AMC had no significant effect on TTP. In advanced stages, ALC/AMC was significant only at the cutoff of 1.1 (10-year TTP 67% vs. 48%; p =.016). In younger, advanced-stage patients, the differences were more pronounced. In multivariate analysis of TTP, ALC/AMC &amp;lt; 1.1 (p =.007) and stage IV (p &amp;lt;.001) were independent prognostic factors; ALC/AMC was independent of International Prognostic Score in another model. ALC/AMC was more predictive of overall survival than TTP. At the cutoff of 1.1, ALC/AMC had independent prognostic value in multivariate analysis. However, the prognostically inferior group comprised only 11% of patients. Further research is needed prior to the widespread use of this promising marker. © AlphaMed Press 2016