In vitro and in silico evaluations of resin-based dental restorative material toxicity.

OBJECTIVES: This study aims to evaluate the cytocompatibility of three provisional restoration materials and predict neurotoxic potential of their monomers. These materials are Tab 2000® (methyl methacrylate based), ProTemp 4™ (bis-acrylic based) and Structur 3® (urethane dimethacrylate based). MATERIALS AND METHODS: Resin samples were incubated in a cell culture medium and the cytotoxic effects of these extracts were studied in 3T3 fibroblast cells through MTT and crystal violet assays as well as ROS assessment. The presence of relevant leached monomers was determined by HPLC. Additionally, the blood-brain barrier (BBB) permeability to these resin-based monomers was predicted using ACD/Labs algorithms model. RESULTS: Cell survival rates were compared with the resin extracts, and Structur 3® was statistically significant different from the others (p < 0.001) at all-time incubation periods. All materials induced a dose-dependent loss of cell viability; however, only Structur 3 extracts were cytotoxic against 3T3 fibroblasts. The highest cytotoxic effect (77%, p < 0.001) was observed at 24 h incubation period, which may be associated with the presence of urethane dimethacrylate (UDMA) leached monomers. Furthermore, the computational model showed that most monomers under study are expectedly capable of crossing the BBB. CONCLUSIONS: Our results showed that Structur 3® is not cytocompatible with our cell model and UDMA is a potential neurotoxic compound. CLINICAL RELEVANCE: These results indicate that only ProTemp 4™ and Tab 2000® are safe for provisional restorations.

In situ Multispecies Colonization of An Acrylic Resin: Comparison to Oral Microbiome and Potential for Inflammatory Response.

BACKGROUND: Conventional acrylic resin is prone to microbial colonization and may cause inflammatory and allergic response. AIMS: This study aims to research the initial microbial adhesion in situ and tissue response to an acrylic resin used in prosthodontics. MATERIALS AND METHODS: Disks of a commercial acrylic resin were prepared and included on the surface of individual intraoral splints fabricated for 50 participants. The splints were used for 4 h, under clinical conditions. Beforehand, each participant was swabbed to provide a control for microbiological comparison. A cytological control sample was also taken from the palate. After the time elapsed, each splint was removed and growth of anaerobes, aerobes, Pseudomonas, oral streptococci, staphylococci, yeasts, and Streptococcus mutans was determined by plate counts and compared to the oral microbiome. A cytological sample was taken from the contact zone, stained using the Papanicolaou technique, analyzed in light microscopy, and classified accordingly. Means and standard deviations were calculated, and a nonparametric Wilcoxon test was employed to compare experimental groups. The significance level was set at 0.05 (95% confidence interval, and statistical analysis was performed using Statistical Package for the Social Sciences (SPSS) version 20.0. RESULTS: Nuclear-cytoplasm ratio increase was found in 84% of the smears retrieved from the contact zone. Over 60% showed nuclear alterations. With exception to yeasts and Pseudomonas, all microbial groups colonized the resin. No statistically significant differences were found between the oral microbiome and the acrylic resin's colonization except regarding yeasts (P > 0.05). CONCLUSIONS: Cellular alterations were found but a diagnosis of inflammation is inconclusive. Microbial adhesion to the acrylic resin was substantial, with multiple species adhering.

Relationship between menopause and periodontal disease: a cross-sectional study in a Portuguese population.

BACKGROUND: Menopause is associated with important systemic and oral changes. Many researchers have tried to evaluate the influence of hormonal changes associated with menopause in the periodontium, however results are contradictory. OBJECTIVE: Evaluate the possible effects of menopause on the severity of periodontal disease and tooth loss, by considering several general, oral and periodontal parameters. METHODS: 102 women with chronic periodontitis, and at least six teeth, were divided into two groups: a study group (SG) consisting of 68 menopausal women and a control group (CG) consisting of 34 premenopausal women. The participants had extensive anamnesis, made by a single senior periodontologist, which collected demographic data, medical and gynaecological history and habits. Additionally, oral and periodontal parameters including: number of teeth, plaque index, presence of calculi, probing depth, bleeding on probing, gingival recession and attachment loss were recorded. The following statistical tests were used: Chi-square, Fisher's t-test for independent samples, non-parametric Wilcoxon-Mann-Whitney, and linear multiple regression. RESULTS: The number of teeth was significantly lower in postmenopausal women (SG 10.8 ± 5.9, CG 6.8 ± 4.6), however, after adjusting for age, smoking and plaque index, the difference was no longer statistically significant (P=0.169). The attachment loss was slightly higher in the study group, although the difference is not significant (SG 4.31 ± 1.08, CG 4.05 ± 1.28). CONCLUSIONS: Menopause does not appear to significantly influence the severity of periodontal disease and tooth loss. Other factors may exert a greater influence on the progression of periodontal disease rather than menopause itself.

Revisiting peri-implant soft tissue - histopathological study of the peri-implant soft tissue.

Peri-implant soft tissues are essential for osseointegration. The peri-implant mucosa may lack vascular supply, and histological observation, even without plaque, shows the presence of inflammatory cells. The objectives of this study were to assess the histopathological changes of the epithelium and connective tissue around the implant. Twenty patients of both genders were studied. Twelve weeks after implant placement, fragments of peri-implant gingival sulcus were harvested and processed for light microscopy. Group I (10): without clinical inflammatory signs (control); Group II (10): with clinical inflammatory signs. Histopathological parameters were analyzed and classified in 3 grades: mild, moderate or severe (grade 1, 2 or 3). Control group showed only slight changes, grade 1. In group II we found edema with moderate to severe cellular and nuclear changes. There are more women than men with all grades of inflammation. All patients with moderate edema are male and all patients with severe edema are female. A significant association (p=0.007) exists between these two variables. Significant differences were found when comparing the degree of inflammation with nuclear alterations (p=0.001) and the same results when comparing the degree of edema and nuclear changes (p<0.001). This study demonstrates that clinical examination can be used, with a small margin of error, to monitor and control the state of the peri-implant mucosa. In clinics the predisposition of female patients to greater degree of edema and inflammation should be accounted for.

Prevalence of yeast other than Candida albicans in denture wearers.

PURPOSE: The isolation of yeast species other than Candida albicans from the oral mucosa has been increasing in frequency, suggesting that those may constitute emerging potential oral colonizers. The purpose of this work was to determine whether yeast species other than C. albicans are associated with factors related to wearing of dental prostheses. MATERIALS AND METHODS: tRNA-PCR fingerprinting and sequencing of the 26S rDNA D1/D2 domain were used to identify all yeasts isolated from CHROMagar™ Candida cultures of oral swabs collected from 178 patients. RESULTS: Besides C. albicans, 13 other species were identified, corresponding to 34% of the yeast isolates. The majority of the non-C. albicans species were not detected as single colonizers but rather in co-colonization with one or two other yeasts, often with C. albicans. No significant associations were found with non-C. albicans species. On the contrary, the best-fitted logistic regression model predicts that either wearing a denture (adjusted odds = 4.6) or insufficient oral hygiene (adjusted odds = 2.3) are risks for colonization by yeast, in general. CONCLUSIONS: The colonization with non-C. albicans species and co-colonization were not independently associated with any of the analyzed host-related factors. In particular, neither wearing a removable denture nor being elderly were significant predictors.

Hepatotoxicity from ingestion of wild mushrooms of the genus Amanita section Phalloideae collected in Mexico City: two case reports.

We present two cases of acute liver injury resulting from consumption of wild mushrooms. The first case was a male who developed acute hepatitis after ingestion of diverse mushrooms including Amanita species. His clinical course was favorable with complete recovery of liver function. The second case was a male who developed acute liver failure (ALF) after ingestion of Amanita bisporigera. He required MARS therapy as a bridge to liver transplantation but transplantation was not performed because he succumbed to multiorgan failure. There are few trials demonstrating the efficacy of the different treatments for mushroom poisoning. These cases demonstrate that the consumption of wild mushrooms without proper knowledge of toxic species represents a serious and under recognized health problem.

Regional bond strength to lateral walls in class I and II ceramic inlays luted with four resin cements and glass-ionomer luting agent.

PURPOSE: To investigate regional shear bond strength to lateral walls of ceramic inlays in occlusal and occlusoproximal cavities using etch-and-rinse and self-adhesive resin cements and a glass-ionomer luting agent. MATERIALS AND METHODS: IPS e.max Press ceramic inlays were made in 50 Class I and 50 Class II standardized cavities in intact extracted human molars and divided into 5 luting agent subgroups (n = 10): Variolink II (VL); Multilink Sprint (MLS); Multilink Automix (MLA); RelyX Unicem (RLX), and Ketac Cem Aplicap (KC). Inlays were pre-etched with IPS Ceramic etching gel for 60s. After 48 h, two disks of ca 1.0 mm thickness, one of superficial and the other of deep dentin, were push-out tested in a universal testing machine at a crosshead speed of 1.0 mm/min. The mode of failure was determined under a stereomicroscope at 20X. Data were analyzed with one way ANOVA, and Scheffé's test was used for post-hoc comparisons (α = 0.05). RESULTS: There were no significant differences in shear bond strength between Class I and Class II cavities for the dual-curing system in light-curing mode (VL=MLS=RLX), except that RLX demonstrated greater bond strength to deep dentin in Class II cavities. Bond strength values were significantly higher on deep than on superficial dentin. KC showed the worst result. Failures were mixed (adhesive/cohesive) for the resin luting cements and solely adhesive (cement/ceramic) for the glass-ionomer luting agent. CONCLUSION: Dual-curing etch-and-rinse or self-etching self-adhesive resin luting cements achieved greater bond strength when light curing was applied, with no differences between Class I and Class II cavities but higher values for deep vs superficial dentin. The weakest adhesion was obtained with glass-ionomer luting agent in both cavity types.

Effects of filling techniques on the regional bond strength to lateral walls in Class I cavities.

OBJECTIVES: Using the push-out technique, this study compared the influence of different composite insertion techniques in Class I cavities on the regional shear bond strength to lateral walls. MATERIALS AND METHOD: Standardized Class I cavities were prepared on the occlusal surface of 60 freshly extracted third molars, which were randomly assigned to one of five groups (n = 10). The cavities were bonded with the self-etch adhesive AdheSE and restored with Tetric Ceram resin composite by one of five techniques: G1, incremental technique (four oblique layers); G2, flowable composite as liner and bulk technique; G3, bulk technique and G4, light cone technique. The total-etch adhesive (Single Bond) and incremental technique were used as the control procedure. Each specimen was sectioned perpendicular to the long axis of the tooth in 1 mm-thick dentin slices. A push-out test was performed to measure regional bond strengths and identify the type of failure. Two additional teeth per group were prepared for the morphological interface study using scanning electron microscopy. RESULTS: Differences between the groups were tested by one-way ANOVA and Scheffé post hoc test (F = 29.635, p < 0.001). The highest shear bond strength values were obtained with the incremental technique, regardless of the adhesive used. Significant differences in bond strength to superficial and deep dentin were only found when a total-etch adhesive was used (Single Bond). CONCLUSIONS: Use of the incremental technique with total-etch or self-etch adhesives is the most effective method of inserting resin-based composites in large Class I cavities.

Comparison of regional bond strength in root thirds among fiber-reinforced posts luted with different cements.

AIM: To compare regional bond strength in different thirds of the root canal, among glass fiber-reinforced (FRC) endodontic posts luted with different cements, using the push-out test. MATERIAL AND METHODS: Sixty extracted human anterior teeth were endodontically treated with gutta-percha and AH Plus sealer. The crown portion was removed, and a dowel space was prepared. Prepared teeth were randomly assigned to one of six groups (n = 10) for luting glass FRC Postec posts, with one of the six cement systems (Ketac Cem Aplicap, Relyx Unicem Aplicap, Variolink II/Excite DCS, Panavia F/ED Primer, C&B cement/All-Bond 2, and Multilink/Multilink Primer A/B), using an alignment technique. Specimens were embedded in resin, and each root was sectioned into six 1-mm thick serial slices. A push-out test was performed to measure regional bond strengths and to identify the type of failure. RESULTS: The highest bond strength values were found in the cervical third and the lowest in the apical third. Highest values were obtained using Variolink II, Panavia F, and Multilink resin cements followed by C&B resin cement and Relyx Unicem ionomer resin cement; Ketac-cem ionomer cement showed the lowest value. CONCLUSION: Highest bond strength values were obtained in the cervical third and with resin cements.

Lombociatalgia decorrente de hidrocefalia: relato de caso / Low back and sciatic pain caused by hydrocephalus

Relata-se o caso de um paciente com quadro de lombocialtalgia decorrente de uma causa atípica: hidrocefalia comunicante. Foi, inicialmente, submetido a exame complementar de imagem da região lombar que não demonstrou anormalidades. Submetido ao tratamento conservador, houve persistência da dor. Na reavaliação, relatou episódios de cefaléia, razão pela qual foi realizada tomografia cerebral que revelou dilatação ventriculoperitoneal. Esse relato sugere a hidrocefalia comunicante como possível etiologia de lombociatalgia.