Faculty Bibliography

Teaching student doctors innovative CAD/CAM technology allows them to develop critical thinking skills to integrate clinical restorative procedures with the precision of graphic design. One way to master this technological advancement is to give student doctors an opportunity to challenge themselves by doing multiple procedures in a single visit. This presentation describes the method in which students use technology and self-assessment criteria to challenge themselves through multiple procedures

OBJECTIVE: This paper presents the results of a clinical study assessing the in vivo effects on plaque metabolism of a new dentifrice containing 1.5% arginine, an insoluble calcium compound, and 1450 ppm fluoride compared to a commercially available dentifrice containing 1450 ppm fluoride alone. METHODS: A four-week, parallel, randomized, double-blind clinical study using 54 subjects was conducted at the New York University College of Dentistry Bluestone Center for Clinical Research. Two study groups used the following products for two weeks: 1) a dentifrice containing 1.5% arginine, an insoluble calcium compound, and 1450 ppm fluoride as sodium monofluorophosphate (MFP; test); and 2) a commercial silica dentifrice with 1450 ppm fluoride as sodium fluoride (NaF; control). In the following two-week period, all subjects used the control product. The effects of product use on plaque metabolism in vivo were assessed by conducting ex vivo analyses at baseline, after two weeks of assigned product use, and after two weeks of control product use. These plaque analyses comprised pH measurements before and after an in vivo sucrose rinse, and measurements of ammonia production and lactate production. RESULTS: The study showed that subjects using the test dentifrice, containing 1.5% arginine, an insoluble calcium compound, and 1450 ppm fluoride, had significantly higher plaque pH values before the sucrose challenge than those using the commercially available control dentifrice (p < or = 0.01). Plaque samples from subjects using the arginine-containing dentifrice also produced significantly higher levels of ammonia (p < or = 0.01). Subjects using the arginine-containing dentifrice also had a directionally higher plaque pH after the sucrose challenge, and their plaque samples produced a directionally lower level of lactate during the two-week treatment period compared to subjects using the control dentifrice. Following two weeks of subsequent use of the control product, there were no significant differences in plaque metabolism measures between groups. CONCLUSION: A new dentifrice containing 1.5% arginine, an insoluble calcium compound, and 1450 ppm fluoride has been shown in this study to modulate plaque metabolism, increasing ammonia production and decreasing lactate production, thereby increasing plaque pH to help restore a pH-neutral environment.

New York University College of Dentistry utilizes a protocol for caries management by risk assessment. It includes guidelines for determining several indicators and factors that are used to identify whether a patient is at high, moderate or low risk for dental caries. This case report presents an assessment of a patient with high caries risk and the system used to treat the disease process and lower the patient's risk for future lesions.

OBJECTIVES: Compressive stress has been intentionally introduced into the overlay porcelain of zirconia-ceramic prostheses to prevent veneer fracture. However, recent theoretical analysis has predicted that the residual stresses in the porcelain may be also tensile in nature. This study aims to determine the type and magnitude of the residual stresses in the porcelain veneers of full-contour fixed-dental prostheses (FDPs) with an anatomic zirconia coping design and in control porcelain with the zirconia removed using a well-established Vickers indentation method. METHODS: Six 3-unit zirconia FDPs were manufactured (NobelBiocare, Gothenburg, Sweden). Porcelain was hand-veneered using a slow cooling rate. Each FDP was sectioned parallel to the occlusal plane for Vickers indentations (n=143; load=9.8N; dwell time=5s). Tests were performed in the veneer of porcelain-zirconia specimens (bilayers, n=4) and porcelain specimens without zirconia cores (monolayers, n=2). RESULTS: The average crack lengths and standard deviation, in the transverse and radial directions (i.e. parallel and perpendicular to the veneer/core interface, respectively), were 67+/-12mum and 52+/-8mum for the bilayers and 64+/-8mum and 64+/-7mum for the monolayers. These results indicated a major hoop compressive stress ( approximately 40-50MPa) and a moderate radial tensile stress ( approximately 10MPa) in the bulk of the porcelain veneer. SIGNIFICANCE: Vickers indentation is a powerful method to determine the residual stresses in veneered zirconia systems. Our findings revealed the presence of a radial tensile stress in the overlay porcelain, which may contribute to the large clinical chip fractures observed in these prostheses.

OBJECTIVE: The objective of this study was to determine the effect of an 8.0% arginine and calcium carbonate desensitizing toothpaste (Colgate Sensitive Pro-Relief) on shear bond strength of composites to bovine incisor dentin. METHODS: Bovine incisors were sectioned and prepared into 27 dentin specimens. The experimental group had 13 specimens treated for 10 sessions of two-minute brushing with an 8.0% arginine and calcium carbonate desensitizing toothpaste, followed by a 30-second agitated water wash. The control group had 14 specimens treated with flour of pumice only. Each specimen was dried, etched with 35% phosphoric acid for 15 seconds, and washed clean. A bonding agent was applied and polymerized. A 2.38 mm diameter column of Filtek Supreme A2 was bonded to the surface and polymerized as per manufacturer's instructions. Specimens were stored in water for at least 48 hours, subjected to a shear force at a crosshead speed of 0.5 mm/minute on an Instron mechanical testing device, and force at failure was recorded. A one-sided t-test was used to evaluate significant differences among the groups as measured by mean shear strength. RESULTS: Mean shear force was 19.6 +/- 9.4 (SD) for the experimental group and 15.4 +/- 6.0 for the control group with p = 0.0291. CONCLUSION: No significant differences were found for bond strength to dentin treated with an 8.0% arginine and calcium carbonate desensitizing toothpaste or pumice. Dentists can still achieve optimal dentin bonding results if a patient is using Colgate Sensitive Pro-Relief to manage dentin hypersensitivity.

In an era of evidence-based care, the question of how much evidence is needed to implement changes into practice becomes central to dentistry's recognition that dental caries management must change to a focus on risk-based, patient-centered disease management rather than just restorative care. This article reviews some of the opportunities, needs, and challenges involved in the adoption and implementation of caries management strategies into everyday clinical practice.