Performance measures to benchmark the grasping, manipulation, and assembly of deformable objects typical to manufacturing applications.

The National Institute of Standards and Technology is developing performance tests and associated artifacts to benchmark research in the area of robotic assembly. Sets of components consistent with mechanical assemblies including screws, gears, electrical connectors, wires, and belts are configured for assembly or disassembly using a task board concept. Test protocols accompany the task boards and are designed to mimic low-volume, high-mixture assembly challenges typical to small and medium sized manufacturers. In addition to the typical rigid components found in assembled products, the task boards include many non-rigid component operations representative of wire harness and belt drive assemblies to support research in the area of grasping and manipulation of deformable objects, an area still considered to be an emerging research problem in robotics. A set of four primary task boards as well as competition task boards are presented as benchmarks along with scoring metrics and a method to compare robot system assembly times with human performance. Competitions are used to raise awareness to these benchmarks. Tools to progress and compare research are described along with emphasis placed on system competition-based solutions to grasp and manipulate deformable task board components.

Benchmarking Protocols for Evaluating Small Parts Robotic Assembly Systems.

This paper presents a set of performance metrics, test methods, and associated artifacts to help progress the development and deployment of robotic assembly systems. The designs for three task board artifacts that replicate small part insertion and fastening operations such as threading, snap fitting, and meshing with standard screws, nuts, washers, gears, electrical connectors, belt drives, and wiring are presented. To support the evaluation of robotic assembly and disassembly operations, benchmarking protocols and performance metrics are presented that leverage these task boards. Finally, robot competitions are discussed as use cases for these task boards.

Treatment of gingival recession using a collagen membrane with or without the use of demineralized freeze-dried bone allograft for space maintenance.

BACKGROUND: Studies utilizing collagen membranes for guided tissue regeneration (GTR)-based root coverage procedures have reported promising results. However, creating and maintaining space underneath the membrane remains a challenge. Therefore, the purpose of this clinical trial was to determine whether the addition of bone graft (i.e., demineralized freeze-dried bone allograft [DFDBA]) significantly affects the outcome of collagen membrane GTR-based root coverage procedures. METHODS: Twenty patients participated. One Miller's Class I or II recession defect per patient was treated with a collagen membrane covered by a coronally positioned flap. Half of the patients also had DFDBA placed under the membrane. Clinical parameters recorded included: recession depth, recession width, width of keratinized tissue, clinical attachment level, and probing depth, measured to the nearest 0.5 mm. Presurgery and postsurgery (6-month) data were compared using Student's paired t test for parametric data and the Wilcoxon matched pairs test for non-parametric data. RESULTS: Guided tissue regeneration with collagen (COLL) and collagen + DFDBA (COBA) both resulted in statistically significant (P <0.05) reductions in recession depth (2.1 +/- 0.9 mm and 2.5 +/- 0.5 mm), recession width (1.5 +/- 1.7 mm and 2.2 +/- 1.6 mm), increase in keratinized tissue (0.7 +/- 0.8 mm and 1.2 +/- 1.0 mm), and gain of clinical attachment level (2.1 +/- 1.0 mm and 3.0 +/- 1.0 mm), when comparing 6-month data to baseline. Mean root coverage was 68.4 +/- 15.2% with COLL and 74.3 +/- 11.7% with COBA. However, there were no statistically significant differences between groups for recession depth, recession width, width of keratinized tissue, clinical attachment level, and probing depth. CONCLUSIONS: Both techniques are effective in attaining root coverage. Although root coverage tended to be better with the addition of DFDBA, the difference was not statistically significant. Further studies with a larger sample size are needed to determine whether adding DFDBA to GTR-based procedures using collagen membranes is of any benefit.

Use of bone grafts for the enhancement of a GTR-based root coverage procedure: a pilot case study.

The use of guided tissue regeneration (GTR) procedures for the treatment of gingival recession has shown encouraging results and is gaining clinical acceptance. However, attaining space maintenance beneath the membrane remains a problem for clinicians. Hence, the purpose of this pilot case study was to evaluate the effect of adjunctive demineralized freeze-dried bone allograft (DFDBA) placement during collagen membrane GTR-based root coverage procedures. Five patients with Miller Class I or II defects were treated with a combination of DFDBA and collagen membrane. Clinical parameters monitored include recession depth, probing attachment level, probing depth, width of keratinized gingiva, and recession width. Measurements were taken at baseline and 6 months. A statistically significant reduction in recession depth (3.1 +/- 0.7 mm) was observed at 6 months, representing 93.4% total attainable root coverage. A significant reduction of recession width (3.5 +/- 1.2 mm) after 6 months was also noted. Clinically, a statistically significant mean gain of 3.3 +/- 0.6 mm in clinical attachment and 0.8 +/- 0.9 mm in keratinized gingiva were obtained at 6 months. No statistically significant difference was found in probing depth between baseline and 6 months postoperative. Plaque and gingival indices remained low and showed no statistically significant change throughout the study period. Results from this pilot case study indicate that use of DFDBA during collagen membrane GTR-based root coverage could be beneficial.