Susana Morimoto

Effect of denture surface glazing on denture plaque formation

This study evaluated, in vivo, the efficacy of a denture glazing material (Palaseal) in modifying plaque colonization of dentures. Ten subjects were selected and received maxillary temporary partial removable dentures, with complete acrylic palatal coverage. The right half of the fitting surface of the denture bases were glazed with Palaseal, whereas the other half was not glazed. One month after insertion, two fragments of the resin base of all dentures were removed (one from the glazed side and another from the non-glazed side). These samples were prepared and examined by scanning electron microscopy. Three months after insertion, other fragments were obtained and analyzed. Microscopic observation at 1 month revealed that, for all patients, the plaque film was thinner on the treated side in comparison to the non-treated side. However, at the 3-month evaluation, some areas of the glaze showed cracking, and both glazed and non-glazed sides were covered by a dense bacterial plaque film. In conclusion, the findings of this clinical experiment showed that glazing dentures fitting surface did not prevent bacterial colonization, but favored plaque removal while the glaze layer remained intact. After three months, glaze cracks created microretentive areas that increased plaque accumulation.

Fracture strength of teeth restored with ceramic inlays and overlays

This study evaluated the fracture strength of teeth restored with bonded ceramic inlays and overlays compared to sound teeth. Thirty sound human maxillary premolars were assigned to 3 groups: 1- sound/unprepared (control); 2- inlays and 3- overlays. The inlay cavity design was Class II MOD preparation with an occlusal width of 1/2 of the intercuspal distance. The overlay cavity design was similar to that of the inlay group, except for buccal and palatal cusp coverage The inlay and overlay groups were restored with feldspathic porcelain bonded with adhesive cement. The specimens were subjected to a compressive load until fracture. Data were analyzed statistically by the Kruskal-Wallis test at 5% significance level. The fracture strength means (KN) were: Sound/unprepared group = 1.17, Inlay group= 1.17, and Overlay group = 1.14. There were no statistically significant differences (p>0.05) among the groups. For inlays and overlays, the predominant fracture mode involved fragments of one cusp (70% of simple fractures). The fracture strength of teeth restored with inlay and overlay ceramics with cusp coverage was similar to that of intact teeth.

Effectiveness of Denture Cleanser Associated With Microwave Disinfection and Brushing of Complete Dentures: In Vivo Study

Complete dentures acts as a reservoir for microbial colonization, which may lead to systemic infections. Microwave irradiation has been used as an efficient method of denture disinfection. Even though current methods eliminate denture-base microorganisms, a recurrence rate of denture stomatitis (DS) is still observed among denture-wearing patients. It was hypothesized that microwave disinfection kills microorganisms but do not remove dead bacteria from the denture surface. To test this hypothesis, the biofilm found in the dentures of 10 patients with DS was evaluated. In addition, the effects of microwave irradiation plus brushing (MW+B) on the denture biofilm and the combination of denture cleanser with microwave irradiation and brushing (MW+DC+B) for the removal of denture-accumulating microorganisms were investigated. Microbiological data were analyzed statistically by nonparametric analysis (Friedman/Wilcoxon, α=0.05). MW+B and MW+DC+B were effective in reducing the rate of microorganisms (99.2% and 99.5% respectively), but without significant difference between them (p=0.553). However, it was observed that the complete removal of microorganisms from denture surface was only possible when all regimens were combined (MW+DC+B). Microwave irradiation in combination with soaking in denture cleanser and brushing effectively disinfected the dentures and removed denture biofilm.

Incisal coverage or not in ceramic laminate veneers: A systematic review and meta-analysis

BACKGROUND There is no consensus on whether incisal coverage is a risk or a protective factor in preparations for ceramic veneers. OBJECTIVE The aim of this systematic review and meta-analysis was to evaluate the survival rates of preparation designs for ceramic veneers with and without incisal coverage. METHODS Primary clinical studies with the following characteristics were included: 1) studies related to ceramic laminate veneers and 2) prospective or retrospective studies conducted in humans. From the selected studies, the survival rates and failures rates for ceramic veneers were extracted according to preparation design, with or without incisal coverage. The Cochran Q test and the I(2) statistic were used to evaluate heterogeneity. Metaregression, meta-analysis were performed. Two reviewers searched in the MEDLINE (Pubmed) and Cochrane Central Register of Controlled Trials (Central) electronic databases, from 1977 to June 5, 2016, without language restrictions. RESULTS Eight studies out of 1145 articles initially identified were included for risk of bias and systematic assessment. No study was identified for crystalline ceramic veneers. The estimated survival rate for laminate veneers with incisal coverage was 88% and 91% for those without incisal coverage. Incisal coverage presented an OR of 1.25. CONCLUSIONS Irrespective of the preparation designs, with or without incisal coverage, ceramic veneers showed high survival rates. As regard implications for future clinical research studies, randomized clinical studies are necessary to compare preparation designs with and without incisal coverage, and to provide clear descriptions of these preparation designs.

The influence of tooth color on preparation design for laminate veneers from a minimally invasive perspective: case report.

Various types of dental preparations for laminate veneers have been proposed,depending on factors such as the properties of the ceramic material, remaining dental structure color, need for altering the dental contour, laboratory fabrication technique, and occlusal relationships. Clinical observations of successes and failures associated with the development of techniques and materials have allowed some safe parameters to be delineated for effectively performing dental preparations for ceramic veneers or even placing veneers without any preparation. This article describes the use of an additive diagnostic wax-up that is transferred to the mouth by means of an intraoral mock-up (aesthetic pre-evaluative temporary) with associated mathematic parameters to guide dental preparations. This technique, called Do the Math and presented here in the form of a clinical case report, aims to avoid excessive or incorrect tooth preparation by indicating the exact amount and location of the tooth reduction necessary to attain the desired color and shape.

Efeito de agentes clareadores na pigmentação extrínseca causada por bactérias cromogênicas: 10 anos de acompanhamento de caso

Some microorganisms are associated with the formation and deposition of pigmentation on dental surfaces, and its localization, intensity and recurrence persistence can introduce aesthetic disorders. Carbamide peroxide is a bleaching agent that also presents antimicrobial properties. This case report addresses a ten-year clinical follow-up, showing a possible influence of a bleaching procedure protocol on alterations of oral microbiota. Although a bleaching treatment does not have the purpose to alter the oral microbiota, a drastic reduction and recurrence of black tooth stains was observed in this case. Indexing terms: Bacteria. Esthetics, dental. Tooth bleaching.