Vital tooth whitening with a novel hydrogen peroxide strip system: design, kinetics, and clinical response.

For many years, at-home whitening has been used with great success and produces some of the most satisfying results of all dental procedures. Historically, the most common procedure used was a custom-fabricated tray loaded with a 10% carbamide peroxide gel that was worn overnight. Today, many manufacturers offer higher concentrations (15% and 20% carbamide peroxide) for faster results. Regardless of the peroxide concentration used, the custom tray delivery system has remained essentially the same. Recently, a trayless whitening system was developed that does not require any prefabrication or gel loading. The new delivery system is a thin, conformable strip precoated with an adhesive hydrogen peroxide gel. Each preloaded strip is presented on a backing liner. To use the strip, it is peeled off of the backing liner and applied to the facial surfaces of the anterior teeth. Each strip is worn for 30 minutes, removed, and discarded. The strip holds the gel in place for sufficient time to allow the peroxide to intrinsically and extrinsically whiten the teeth. The highly flexible strips conform intimately to the tooth surface and provide a uniform, controlled application of the peroxide gel.

Impact of demographic, behavioral, and dental care utilization parameters on tooth color and personal satisfaction.

A cross-sectional survey across broad age ranges was conducted to evaluate demographic, behavioral, and treatment parameters that impact tooth color and its perception. The sample included 180 US adults and teenagers, with a comparable representation of males and females in 6 different age strata, ranging from 13 to 64 years. Tooth color (L*a*b*) was measured on the maxillary central incisors using a spectrophotometer, and first-person satisfaction with tooth color was assessed using a five-point qualitative scale. Demographic, behavioral, and oral care parameters were modeled using multiple regression analysis. After adjusting for other explanatory variables, age, gender, coffee/tea consumption, and dental care all significantly affected yellowing (b*) and brightness (L*). Dental-visit frequency was the only factor that significantly predicted self-satisfaction with tooth color, explaining just 3% of the overall variability. First-person dissatisfaction with tooth color was common and found in most demographic and behavioral cohorts. Although age contributed to objectively measured tooth discoloration, personal satisfaction with tooth color was age-independent. These results suggest that the need or demand for esthetic dentistry may be broad-based and transcend stereotypical perceptions.

Development and characterization of an in vitro gingival epithelial model.

A 3-dimensional gingival epithelial model has been developed and characterized. Oral epithelial cells and connective tissue fibroblasts were isolated from human gingival tissue and used to create an in vitro oral mucosa co-culture model. Fibroblasts were seeded on a scaffold of nylon mesh, allowed to proliferate and secrete collagen and extracellular matrix proteins to form a stroma capable of supporting the growth of epithelial cells. Epithelial cells were seeded on top of a confluent stromal layer, proliferated and differentiated to form a stratified squamous epithelium. Resident epithelial cells were stimulated, by manipulation of growth medium and culture conditions, to form a multi-layered oral mucosa-like tissue. Histologic analyses revealed cellular architecture exhibiting stromal-epithelial interaction which supports the growth and differentiation of an epithelial layer. Immunohistochemical analyses confirmed production of types I and III collagen. Immunofluorescence of the stromal layer identified type IV collagen and fibronectin. Fibronectin was also detected on surface epithelium. Differentiation of basal, spinous and granular cells was observed, and the presence of differentiation markers, acidic (K10, 14-16, 19) and basic (K1-8) cytokeratins were confirmed using broad spectrum cytokeratin antibodies, AE1 and AE3. Development of a discontinuous basal lamina zone, with hemidesmosomes, was observed by electron microscopy. The co-culture was metabolically active, as measured by the thiazoyl blue (MTT) assay for mitchondrial function and [3H] thymidine incorporation into DNA. The human gingival epithelial co-culture model was viable up to 35 days post-epithelial seed. This model may offer opportunities for limited study of periodontal tissue responsiveness.