Resin composite thickness' influence on L*a*b* coordinates and translucency.

OBJECTIVES: To evaluate if material thickness can influence the L*a*b* coordinates and translucency of different composite shades. MATERIALS AND METHODS: Twelve composite disc specimens made of three different resin composite materials (dentin A2, Essentia, GC; body shade A2, Brillant Everglow, Coltene-Whaledent; enamel skin neutral, Inspiro, Edelweiss DR) and of three different thicknesses 0.5, 1.0, and 1.5 mm were readied. L*a*b* coordinates of the 118 specimens were assessed by a calibrated reflectance spectrophotometer over a black as well as a white background. RESULTS: Over the black background, median ΔE00 values varied from 0.7 (Brilliant Everglow) to 1.5 (Inspiro SN) for 0.5-mm composite thickness (intrinsic color variation) and from 3.2 (Essentia) to 7.5 (Inspiro SN) for 1.0 mm, respectively 6.1 (Essentia) to 11.1 (Inspiro SN) for 1.5-mm composite thickness (color variation related to thickness). Over the white background, median ΔE00 values varied from 0.6 (Essentia) to 1.6 (Inspiro SN) for 0.5-mm composite thickness and from 2.9 (Inspiro SN) to 4.3 (Essentia) for 1.0 mm, respectively 4.9 (Inspiro SN) to 7.0 (Essentia) for 1.5-mm composite thickness. Transparency varied from 25.2% (Essentia) to 34.6% (Inspiro SN) for 0.5-mm composite thickness, from 20.3% (Essentia) to 27.5% (Inspiro SN) for 1.0-mm thickness and from 14.8% (Essentia) to 22.9% (Inspiro SN) for 1.5-mm thickness. CONCLUSIONS: Material thickness can influence the L*a*b* coordinates and translucency of different composite shades. CLINICAL RELEVANCE: L* a* b* coordinates are influenced by composite thickness.

Color stability of recent composite resins.

The objective of the study was to evaluate the color stability of 8 recently developed resin composites when exposed to various staining agents. Six disc-shaped specimens made out of 8 resin composite materials were immersed in artificial saliva, coffee, coke, tea, orange juice and red wine. The initial color (T0) of the 288 specimens was assessed by a calibrated reflectance spectrophotometer (SpectroShade, MHT) over a black as well as a white background. All specimens were kept in an incubator (INP-500, Memmert GmbH) at 37 °C for 4 weeks. Colorant solutions were changed every 7 days to avoid bacteria or yeast contamination. After 4 weeks of storage in the colorants (T1), spectrophotometric measurements were repeated and ΔE00 was calculated. When analyzed over a white background, the mean ΔE00 values varied from 1.5 (Venus Diamond) to 52.4 (Miris 2). When analyzed over a black background, the mean ΔE00 values varied from 0.8 (Venus Diamond) to 40.0 (ELS). Significant differences were detected when comparing values at T0 and T1 (ΔE00) for both backgrounds (Anova and Fisher's LSD post hoc test). Resin composite materials do behave in a significantly different way (p value < 0.01) when exposed to various staining solutions.

Caries diagnosis using light fluorescence devices: VistaProof and DIAGNOdent.

The modern concept of minimally invasive dentistry encompasses early detection of incipient carious lesions and their treatment. Due to the low sensitivity of visual inspection and radiography in the detection of occlusal hidden carious lesions under a macroscopically sound surface, several devices have been developed to increase detection accuracy. DIAGNOdent is one of the tools used for that purpose and VistaProof is a new device recently introduced into the market. They both use light fluorescence to detect incipient carious lesions. DIAGNOdent is based on the fact that carious lesions show higher level of fluorescence than sound tissues when excited by light at specific wavelength. Vistaproof is based on the same principle, but it uses a different wavelength of excitation than DIAGNOdent and a video camera for the detection of fluorescence. The aim of this article was to compare these two devices and present their clinical use.

Local anesthetics induce autophagy in young permanent tooth pulp cells.

Pulp cells are essential for tooth development, and dentin repair and regeneration. In addition these cells have been identified as an important stem cell source. Local anesthetics are widely used in dental clinics, as well as the other clinical disciplines and have been suggested to interfere with human permanent tooth development and induce tooth agenesis through unknown mechanisms. Using pig model and human young permanent tooth pulp cells, our research has identified that the local anesthetics commonly used in clinics can affect cell proliferation. Molecular pathway profiling suggested that LC3II is one of the earliest molecules induced by the agents and p62 is the only common downstream target identified for all the drugs tested. The effect of the drugs could be partially recovered by V-ATPase inhibitor only if early intervention is performed. Our results provide novel evidence that local anesthetics could affect tooth cell growth that potentially can have impacts on tooth development.

Amelogenesis imperfecta: a conservative and progressive adhesive treatment concept.

OBJECTIVE: The aim of this study was to present a case report of a patient affected by amelogenesis imperfecta showing a possible minimal and conservative adhesive treatment approach. CLINICAL PROCEDURE: A treatment philosophy of amelogenesis imperfecta is illustrated by means of a case report of a 14-year-old boy who consulted us for a full mouth rehabilitation. DISCUSSION: This clinical report describes step by step how to manage a case of amelogenesis imperfecta from childhood over time. SIGNIFICANCE: This kind of minimally invasive, progressive approach allows the conservation of maximum tooth substance together with an acceptable esthetic outcome.

Response to psychotherapy in borderline personality disorder and methylation status of the BDNF gene.

Downregulation of brain-derived neurotrophic factor (BDNF) gene expression with corresponding increased methylation at specific promoters has been associated with stressful experiences in early life and may explain later adulthood psychopathology. We measured the percentage of methylation at BDNF CpG exons I and IV as well as plasma BDNF protein levels in 115 subjects with borderline personality disorder (BPD) and 52 controls. BPD subjects then underwent a 4-week course of intensive dialectical behavior therapy (I-DBT). BDNF methylation status and protein levels were re-assessed at the end of treatment. BPD subjects had significantly higher methylation status in both CpG regions than controls. In addition, the higher the number of childhood trauma, the higher was the methylation status. In BPD subjects, BDNF methylation significantly increased after I-DBT. Nonresponders accounted for the majority of this increase, whereas responders showed a decrease in methylation status over time. Accordingly, the changes in methylation status over time were significantly associated with changes in depression scores, hopelessness scores and impulsivity. No association was found between protein levels and BDNF methylation status. We here found a relationship between child maltreatment and higher DNA methylation of BDNF. These results moreover support the idea that these epigenetic marks may be changed through psychotherapeutic approaches and that these changes underline changes in cognitive functions.

A novel evaluation method for optical integration of class IV composite restorations.

BACKGROUND: This aim of this study was to compare traditional visual appreciation with spectrophotometry to evaluate the optical integration of anterior composite restorations. METHODS: Eleven restorations were evaluated in eight patients receiving dental treatment at fourth and fifth year student clinics at the dental school of the University of Geneva, Switzerland. Colour integration of completed restorations was assessed by visual observation according to USPHS criteria and spectrophotometric analysis; both methods were then compared. RESULTS: A mean ΔE of 1.1 (range 0.7 to 1.7) corresponded to an optimal visual integration between natural tooth and restoration (alpha score) while a mean ΔE of 3.3 (range 2.6 to 3.8) corresponded to clinically 'non-acceptable' visual integration (charlie score). Restorations scored as 'bravo', corresponded to a suboptimal but not disturbing visual integration, had a mean ΔE of 2. L* and b* values present at the bevel area and into the composite bulk tended to be lower than that of the natural tooth while a* composite values were slightly higher. CONCLUSIONS: The spectrophotometric method employed in this pilot study has confirmed the published range of ΔE (global difference of L*a*b* values) corresponding to clinically 'optimal', 'acceptable' and 'unacceptable' colour integration.

A combined chemo-mechanical approach for aesthetic management of superficial enamel defects.

OBJECTIVE: The aim of this article is to describe an easy technique for managing small superficial defects in light to medium fluorosis. METHOD AND MATERIALS: The proposed technique is based on a selective abrasion of the superficial enamel and a recreation of the superficial macro and micro morphology. The aesthetic appearance can be enhanced by power or home bleaching. RESULTS: The presented technique can manage enamel defects which are confined in the most external enamel surface with satisfying aesthetic results. CONCLUSIONS: This conservative approach may be considered an interesting alternative to more invasive prosthetic techniques based on composite reconstructions or ceramic veneers, minimising invasivity, chairside time and costs for patients.