Wireless, intraoral hybrid electronics for real-time quantification of sodium intake toward hypertension management.

Recent wearable devices offer portable monitoring of biopotentials, heart rate, or physical activity, allowing for active management of human health and wellness. Such systems can be inserted in the oral cavity for measuring food intake in regard to controlling eating behavior, directly related to diseases such as hypertension, diabetes, and obesity. However, existing devices using plastic circuit boards and rigid sensors are not ideal for oral insertion. A user-comfortable system for the oral cavity requires an ultrathin, low-profile, and soft electronic platform along with miniaturized sensors. Here, we introduce a stretchable hybrid electronic system that has an exceptionally small form factor, enabling a long-range wireless monitoring of sodium intake. Computational study of flexible mechanics and soft materials provides fundamental aspects of key design factors for a tissue-friendly configuration, incorporating a stretchable circuit and sensor. Analytical calculation and experimental study enables reliable wireless circuitry that accommodates dynamic mechanical stress. Systematic in vitro modeling characterizes the functionality of a sodium sensor in the electronics. In vivo demonstration with human subjects captures the device feasibility for real-time quantification of sodium intake, which can be used to manage hypertension.

Randomized, prospective, clinical evaluation of prosthodontic modalities for mandibular implant overdenture treatment.

STATEMENT OF PROBLEM: Mandibular implant overdentures provide improved treatment outcome than conventional denture therapy, but there is controversy as to which overdenture treatment is the best choice. PURPOSE: This study evaluated 3 different mandibular implant overdenture treatments with respect to prosthesis retention and stability, tissue response, patient satisfaction and preference, and complications to determine treatment outcomes. MATERIAL AND METHODS: In a prospective, randomized clinical trial, using a crossover design, 30 subjects (mean age, 58.9; 63% male) received 4 implants in the anterior mandible. For each subject, 3 different overdenture attachment types were fabricated and/or fitted to the implants. These included a 4-implant bar attachment fitted to all 4 implants, a 2-implant bar attachment, and 2 independent ball attachments. Subjects were randomly assigned to 1 of 6 possible treatment sequences and received all 3 attachment types each for approximately 1 year. Data were collected at baseline, and at 6 and 12 months for treatment types. Denture retention and stability and parameters of soft tissue response were recorded. Complications were documented and questionnaires were used to identify subject masticatory ability, denture complaints, and preferences. Data were analyzed to determine statistical equivalence among the 3 different treatments using the Schuirmann's two one-sided test (TOST) procedure, and the Wilcoxon-Mann-Whitney TOST procedure (α=.05). RESULTS: Force gauge prosthesis retention measurements showed that the 3 treatment types were not statistically equivalent, with the 4-implant bar demonstrating the greatest retention. Criterion-based retention scores were statistically equivalent for all treatments. Both the force gauge and criterion-based prosthesis stability measurements were statistically equivalent among all 3 treatment types. Analysis of all other multiple criterion-based scoring systems indicated the majority of these variables demonstrated equivalence. Where equivalence was not identified, the most favorable responses were typically found with the O-ring treatment, and the least favorable with the 4-implant bar treatment. From the small percentage of treatment visits demonstrating minor complications, no single treatment presented with greater complications than the others. For the treatment preference among subjects, 52% selected the independent ball attachment, 32% the 4-implant bar, and 16% the 2-implant bar (P=.10). CONCLUSIONS: The 2-implant independent treatment used in this study provided equivalent or more favorable treatment outcomes for most measured parameters relative to the more complex and costly 2- and 4-implant bar attachments. The 4-implant bar treatment provided greater prosthesis retention than the other treatment types in this study, but after experience with all systems, subjects were more satisfied with and preferred the independent implant treatment.

Influence of a 3-step tooth disinfection procedure on dentin bond strength.

STATEMENT OF PROBLEM: Clinicians have used disinfection materials to remove surface contaminants during cavity preparation. It has been postulated that disinfection materials may negatively affect shear bond strength of restorative materials. If so, large numbers of restorations may be predestined for early failure with the use of a disinfection protocol. PURPOSE: The purpose of this study was to determine whether there is a difference in the bond strength between dentin and resin composite with a 3-step disinfection technique compared to a conventional bonding technique without the additional disinfection protocol. MATERIAL AND METHODS: Sixty human molar teeth were sectioned parallel to the occlusal surface to expose mid-coronal dentin and mounted parallel to a bond shearing device on a universal testing machine and divided into 2 groups. In the 3-step disinfection group (n = 30), specimens were treated with chlorhexidine, Tubulicid red, and sodium hypochlorite before dentin bonding, following the manufacturer's instructions for All Bond 2. In the control group (n = 30), specimens were treated only with the bonding protocol of All Bond 2. To ensure a uniform bond surface area, core paste was syringed into a cylindrical mold (2.38-mm diameter and 2.00-mm height) that was in contact with the dentin bonding surface of each specimen and allowed to polymerize under constant force. All specimens were subjected to fracture by shear loading in a universal testing machine at a uniform crosshead speed of 0.05 mm per minute and expressed as MPa. Statistical analysis was performed using the Student t test (alpha = .05). The mode of failure was noted after a visual examination using a light microscope under x30 magnification. Failures were recorded as adhesive, cohesive or mixed, and statistical analysis was performed using a chi-square of homogeneity (alpha = .05). RESULTS: A significantly higher shear bond strength was found for the 3-step disinfection group (mean shear bond strength, 25.3 +/- 4.6 MPa) compared to the control group (mean shear bond strength, 20.5 +/- 3.4 MPa) (P < .0001). Most failures were adhesive for the control group, but the fracture modes were evenly divided for the 3-step disinfection protocol group. A chi-square test of homogeneity showed a value of 12.3, df = 2, P = .0012. CONCLUSIONS: The 3-step disinfection technique group showed a significantly stronger dentin shear bond strength compared to the conventional bonding technique without disinfection.