Effect of CPP-ACP on remineralization of artificial caries-like lesion: an in situ study

Abstract The purpose of this double-blind, randomized, crossover in situ study is to compare remineralization of preformed enamel lesions by casein phosphopeptide-stabilized amorphous calcium phosphate (CPP-ACP) and fluoride dentifrice products. During each of four 10-day experimental legs, 10 participants wore intraoral removable palatal acrylic appliances with four human enamel slabs with preformed lesions. A 0.03-mL treatment paste was dripped extraorally onto the enamel blocks once a day for 3 min. The four randomly allocated treatments were as follows: CO- Control: silica dentifrice without fluoride; MP: MI Paste; MPP: MI Paste Plus and FD: Fluoride dentifrice - 1100 ppm F as NaF). Knoop surface hardness (SH) test was performed in three stages (T0 - sound enamel, T1 - after preformed lesion, and T2 - after treatment) and the cross-sectional hardness (CSH) test was performed after treatment using a 50-gram Knoop load for 15 s. Knoop hardness number (KHN) was similar between treatments. %SHr was significantly higher in the MP, FD, and MPP when compared to CO group (Kruskal-Wallis and Mann-Whitney tests, p < 0.05). Harder enamel was found in MP (75 μm) and FD groups at 75 to 175 μm. Treatment with DF, MP, and MPP promoted an increase of 20.27%, 19.24%, and 14.71%, respectively, in Integral Hardness Change (ΔIHC) when compared to CO (p<0.05). Remineralizing agents (MP, MPP, and DF) were able to inhibit demineralization of human enamel subjected to high cariogenic challenge in situ. DF had the greatest preventive potential against the progression of carious lesions.

EFEITO DOS AGENTES DE CROSS-LINKING NA DURABILIDADE DA INTERFACE ADESIVA / EFFECT OF CROSS-LINKING AGENTS ON THE DURABILITY OF THE ADHESIVE INTERFACE

As metaloproteinases (MMPs) são enzimas colagenolítcas endó- genas, capazes de degradar as fibrilas de colágeno presentes na dentina, gerando falhas da interface adesiva. Foram propostos agentes de cross-linking para diminuir essa degradação. O objetivo desta revisão de literatura foi analisar a ação de diferentes agentes de cross-linking sobre as MMPs. A seleção dos artigos foi realizada por meio de uma busca na base de dados PubMed/MEDLINE. A amostra final foi composta por 40 estudos publicados entre 2018 e 2010. Os estudos atuais apresentaram os agentes de cros-s-linking (cabordiimida, glutaraldeído, proantocianidina, riboflavina/ UV-A e quitosana) com vantagens como inespecificidade em relação aos tipos de MMPs, aumento da resistência da fibra colágena e possibilidade de bloquear o sítio de clivagem da enzima. Ob- servou-se que a cabordiimida, riboflavina/UV-A, o glutaraldeído, a proantocianidina e a quitosana apresentaram resultados positivos na diminuição da degradação da interface adesiva. A carbodiimida e riboflavina/UV-A não são citotóxicas, diferentemente do glutaraldeído. A proantocianidina, quando incorporada no adesivo, apesar de interferir na polimerização dos monômeros adesivos, pode ser efetiva quando utilizada incorporada ao condicionamen- to ácido. A quitosana é capaz de reforçar as fibrilas de colágeno. Assim, foi possível conhecer mais sobre a ação dos agentes de cross-linking disponíveis. No entanto, há necessidade de mais pesquisas sobre esses agentes.

Metalloproteases are endogenous collagenolytic enzymes, capable of degrading the collagen fibrils present in the dentin, producing adhesive interface failures. Cross-linking agents has been proposed to reduce this degradation. The aim of this literature review was to analyze the action of different cross-linking agents on MMPs. The search was conducted in the PubMed database. The final sample consisted of 40 studies published between 2018 and 2010. Current studies have shown cross-linking agents (cabordiimide, glutaraldehyde, proanthocyanidin, riboflavin / UV-A and chitosan) present some advantages as non- specificity to type of MMPs, collagen fiber's toughness development and prevent bonding to the cleavage site of the enzyme. For this reason, it is necessary to know the action of the available cross-linking agents. It was observed that Cabordiimide, riboflavin / UV-A, glutaraldehyde, proanthocyanidin and chitosan presented positive results in reducing degradation of the adhesive interface. Carbodiimide and riboflavin / UV-A are non-cytotoxic, unlike glutaraldehyde. Proanthocyanidin incorporated into the adhesive interferes with the polymerization of the adhesive monomers. Chitosan is able to reinforce collagen fibrils. Thus, it was possible to know more about the action of the available cross-linking agents. However, there is a need for more research on these agents.