Matrix metalloproteinases are enzymes that degrade the extracellular matrix. They have different substrates but similar structural organization. Matrix metalloproteinases are involved in many physiological and pathological processes and there is a need to develop inhibitors for these enzymes in order to modulate the degradation of the extracellular matrix (ECM). There exist two classes of inhibitors: endogenous and synthetics. The development of synthetic inhibitors remains a great challenge due to the low selectivity and specificity, side effects in clinical trials, and instability. An extensive review of currently reported synthetic inhibitors and description of their properties is presented.

Aim To summarize and report laboratory studies of adhesion in eroded substrates, which used bond strength as an outcome measure. To determine the strategies available to overcome bonding difficulties, the quality and consistency of the methodology and to find evidence gaps. Materials and Methods The present review followed PRISMA-ScR guidelines. A search was conducted on PubMed/Medline, Scopus and EMBASE (Ovid) databases to identify published peer-reviewed papers (2010–2020). For final qualitative synthesis, 29 articles were selected which respected the inclusion criteria. Data charting was carried out, independently, by two reviewers and quality assessment of the articles was performed. Results The primary studies included fall into four major categories: comparison of restorative materials and application modes, enzymatic inhibitors, surface pretreatments or remineralization strategies. Most studies found evaluated dentin (76%), while 17% evaluated enamel, and 7% evaluated both substrates. The majority of the studies reported an effective intervention (83%). Bond strength to eroded dentin is significantly reduced, while in enamel erosion is beneficial. The bond strength to eroded dentin is material-dependent and favored in systems containing 10-MDP. Great disparities among the erosion models used were found, with citric acid in different concentrations being the preferred method, although standardization is lacking. Conclusions Adhesives containing 10-MDP show beneficial results in eroded dentin, and surface preparation methods should be considered. Studies which evaluated adhesion to eroded enamel/dentin show high heterogeneity in what concerns aims and methodology. Strategies that focus on remineralizing dentin and strategies to protect bond longevity in this substrate require further research.

Surface properties of composites such as roughness and color impact periodontal health and aesthetic outcomes. Novel bulk-fill composites with improved functionality are being introduced and, in light of the existing variety of finishing/polishing procedures, research of their surface properties is warranted. Sixty discs were prepared from bulk-fill composites (Filtek™ Bulk Fill Posterior Restorative and Fill-Up™) and incremental-fill Filtek™ Z250. They were further divided according to different polishing procedures (n = 5): three multi-step polishing procedures or finishing with a bur (control). Surface roughness (Ra) was measured using an atomic force microscope (The AFM Workshop TT-AFM). A spectrophotometer (Spectroshade Micro Optic) was used to determine color stability, after exposure to a coffee solution. Data were analyzed using two-way MANOVA (significance level of 5%). Resin composite type, polishing procedure, and their interaction had a statistically significant effect on surface roughness (p < 0.001) and color change (p < 0.001). Fill-Up™ exhibited the highest surface roughness and greatest color change. Differences in color change were statistically significant (p < 0.001). Filtek™ Bulk Fill registered the lowest surface roughness and color change, after the three-step polishing procedure. Both parameters were significantly correlated (ρ = 0.754, p < 0.001) and found to be material dependent and polishing-procedure dependent. Higher surface roughness relates to greater color changes.

The aim was to evaluate the effect of different antioxidant agents on the improvement of bond strength to enamel subjected to a whitening procedure. Samples were divided into six groups (n = 10): control; whitening immediately followed by restorative treatment (WHT); whitening and restoration after a 7-day period (WHT_7D); whitening and application of 10% sodium ascorbate (WHT_SA); application of 5% grape seed extract (WHT_GS); and application of 5% green tea (WHT_GT). All groups except for control fwere whitened (Opalescence PF Regular 16%) for 7 days (4 h/day). All samples were restored (Optibond™ FL, Kerr and Filtek™ Z250 composite, 3M ESPE). In antioxidant groups these were applied for 15 min and immediately restored. Specimens were sectioned in microspecimens (1.0 ± 0.2 mm2 area) for microtensile bond strength (μTBS) testing (0.5 mm/min) on a universal testing machine. ANOVA test with Brown-Forsythe correction and Games-Howell post-hoc test was used (significance level of 5%). Antioxidant groups presented significant higher mean μTBS values than group WHT (p < 0.001). The non-whitened control group was not significantly different to antioxidant experimental groups. Group WHT_7D exhibited a significantly higher mean μTBS value when compared to group WHT (p = 0.022). The different antioxidants significantly influenced microtensile bond strength of restored teeth after whitening.

Collagen cleavage by matrix metalloproteinase (MMP) is considered a major cause of dental resins long term failure. Most MMP inhibitors display significant toxicity and are unsuitable for dental resins’ applications. Here we report a study of a new class of inhibitors that display the unique property of being co-polymerizable with other vinyl compounds present in commercial dental resins, limiting their release and potential toxicity. Computational affinity towards the active site of different MMP-1; -2; -8; -9 and -13 of several compounds showed interesting properties and were synthesized. These free compounds were tested concerning their toxicity upon contact with two different cell types, with no substantial decrease in cell viability at high concentrations. Even so, compound’s safety can be further improved upon copolymerization with commercial dental resins, limiting their release.

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View related articlesView Crossmark data radiolucent. They grow slowly and asymptomatic, unless there is a secondary infection, in this case they are associated with swelling and pain [2]. The dentigerous cyst of inflammatory origin is related with the inflammation present at the root apex of a non-vital primary tooth which spreads to involve the follicle of the unerupted immature permanent successor [3], as is in this case. Therapeutic modalities range from marsupialization and decompression to enucleation [2]. Materials and methods: Male, 8 years old, appeared in the emergency appointment with pain and continuous abscess in the region of the second lower left deciduous molar. Extraoral examination revealed facial asymmetry. Intraoral examination revealed mixed dentition and in the lower left vestibule a hard, non-fluctuant swelling extending laterally from mesial surface of the mandibular first deciduous molar to the distal surface of the mandibular second deciduous molar, both with carious lesions and grade II mobility. Orthopantomography, revealed a well-circumscribed unilocular radiolucent lesion in the body of the jaw on the left side, which was associated with the crown of a vertically impacted second premolar with its subsequent displacement. Based on clinical and radiological findings, a provisional diagnosis of dentigerous cyst was made. We obtained the informed consent authorised by the ethics committee signed by the minor parents and let me reinforce that all the clinical case was made accordingly with the Helsinki Declaration of Ethical Principals. Firstly we did the extraction of the first and second lower left deciduous molar under local anaesthesia (2% Lidocaine with 1:1,000,000 Epinephrine), along with cyst enucleation through the extraction socket, preserving the impacted second premolar. The surgical piece was sent to histopathological examination in a tube with formaldehyde 37%. Results: Inflammatory dentigerous cysts was histopathological confirmed. Follow up period was 15 days, 1 month, 5 months and 10 months. After 15 days the patient referred substantial improvements on pain and the disappearing of the facial asymmetry as well as improvement on function, comfort and quality of life. It was then sent to Orthodontic treatment. At the 10 months follow up, it was removed the lingual arch due the eruption of definitive teeth. Discussion and conclusions: The dentigerous cysts are mostly found on routine radiographic examinations or by enlargement of affected region in the jaw with pain [3]. The pathogenesis of dentigerous cyst is still controversial but, one of the feasible proposed mechanisms is that the follicle of permanent successor might get secondarily infected from either periapical inflammation of a non-vital predecessor or other source leading to a dentigerous cyst formation [3]. Patient age, cyst size, site, involved dentition, and affected vital structures, are criteria which must be considered in the treatment modality, in this case we have a young patient and we opted for enucleatio...