The efficiency of mesh structures for the attachment of soft tissues to implants was demonstrated. A mesh spacing of approximately 200 microm was observed to be favorable for the anchorage of fibrous tissues.

Soft tissue attachment is a major concern for the improved design of dental and maxillofacial implants. This study evaluated the efficacy of mesh structures for soft tissue attachment in a rat percutaneous model. Four kinds of implant specimens were prepared - TI implants made of titanium cylinders, HA implants of hydroxyapatite-coated titanium, TI-Mesh implants with a titanium mesh covering a groove machined around a titanium cylinder, and similar HA-Mesh implants with a hydroxyapatite-coated mesh. These specimens were implanted percutaneously into the skin tissue of rats. The detachments of the implants were examined during the experimental period of 4 weeks. Survived implants were subjected to mechanical tests for the attachment strength and histological examinations. TI and HA implants demonstrated 0% of survival rates, while TI-Mesh and HA-Mesh showed significantly higher rates of 93.3% and 100% respectively. The attachment strengths were 159 ± 47 kPa in the TI-Mesh and 135 ± 16 kPa in the HA-Mesh. Histological observations revealed that collagen fibers originating from surrounding subcutaneous tissues were anchored to the mesh structures of the TI- and HA-Mesh implants. The results demonstrated the efficacy of the mesh structures for the attachment of soft connective tissues to implants.

In this study, we investigated the use of perforated sheet platforms to improve the attachment of percutaneous devices to surrounding tissues. The model platform was created by a poly(methyl methacrylate) (PMMA) sheet with a matrix of 200-microm diameter perforations covering the groove (width, 3 mm; depth, 0.5 mm) prepared on the PMMA cylinder (diameter, 10 mm; length, 6 mm). Velour cuffs from peritoneal dialysis catheters were used as controls. Specimens were implanted percutaneously in rats, harvested with the surrounding tissues at 4 weeks after surgery, and subjected to mechanical tests and histological observations. The attachment strength of the experimental specimens to tissue was 138.4 +/- 123.6 kPa (n = 5, mean SD); although it was greater than the 67.23 +/- 45.78 kPa (n = 5) of the controls, no statistical significance was found. Histological observations of the experimental specimens revealed the collagen fibers originating from the surrounding tissues, passing through the perforations of the sheet, merging into the collagen fibers running behind the sheet, and thus anchoring the tissues to the device. In contrast, such anchoring of collagen fibers was not evident in the controls. These results suggest that the proposed perforated sheet structures are effective for soft tissue attachment.

Effectiveness of mesh-like interface for percutenous devices was studied with a rat model. The purpose of this study was mechanical and histological evaluation of a percutaneous device model on which a sheet with many small holes was adhered as a mesh-like interface to tissues. The model was prepared by adhering a 0.2-mm thick PMMA sheet with 10 rows × 100 columns of 200-µm laser-processed holes to a machined PMMA cylinder of 10-mm diameter and 6-mm height with a circumference groove. The sheet was placed over the groove and thus provided a mesh-like interface for mechanical attachment. Similar specimens without laser-processed holes were also prepared and used as controls. The specimens were implanted into dorsal skin of rats for 4 weeks. The attachment strength test and histological observation was carried out for the retrieved specimens. The attachment strength of the devices with mesh-like interface was measured as 3.59 ± 3.93 N (n = 10), that was statistically greater than that of controls. Histological observations revealed that collageneous fibers coming from surrounding tissues entered through the holes of the mesh-like interface of the model. This finding confirmed that the mechanical attachment of tissues was realized. Thus the effectiveness of the mesh-like interface for percutenous devices was demonstrated.

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