Multi-center clinical comparison of combination anorganic bovine-derived hydroxyapatite matrix (ABM)/cell binding peptide (P-15) and ABM in human periodontal osseous defects. 6-month results.

BACKGROUND: Intraosseous periodontal defects present a particular treatment problem. New bone replacement grafts offer promise for improved results. METHODS: The role of a synthetic cell-binding peptide (P-15), combined with anorganic [corrected] bovine-derived hydroxyapatite bone matrix (ABM), was compared to ABM alone in human periodontal osseous defects in a controlled, monitored, multi-center trial. Following appropriate initial preparation procedures, flap surgery with defect and root debridement was performed. Two osseous defects per patient were treated randomly with each procedure after surgical preparation. Appropriate periodontal maintenance schedules were followed, and at 6 to 7 months, re-entry flap surgery was performed for documentation and finalization of treatment. RESULTS: T test and Mann-Whitney U analyses of patient mean values from 33 patients revealed that the combination ABM/P-15 grafts demonstrated significantly better mean defect fill of 2.9 +/- 1.2 mm (72.9%) versus a mean defect fill of 2.2 +/- 1.4 mm (50.67%) for defects treated with ABM (P<0.05). Other hard tissue findings showed similar clinically superior results with the use of ABM/P-15. Relative defect fill results showed 81% positive (50% to 100% defect fill) responses with ABM/P-15 and 67% positive responses with ABM. There were 3.5 times as many optimal results (> or = 90% defect fill) with ABM/P-15 and twice as many failures (minimal response) with ABM. Soft tissue findings showed no significant differences between treatments. CONCLUSIONS: These results suggest that the use of the P-15 synthetic cell-binding peptide combined with ABM yields better clinical results than the ABM alone in intrabony periodontal defects.

Fatigue properties of hydroxyapatite-coated dental implants after exposure to a periodontal pathogen.

We studied the fatigue properties of rods (4 mm diameter) of hydroxyapatite-coated, titanium alloy implant material after it was exposed to a periodontal pathogen, Actinobacillus actinomycetemcomitans (Aa). We varied the crystallinity of the hydroxyapatite (HA) coating in these rods to the levels of, 60.5%, 52.8%, and 47.8%. Each rod was first inoculated with Aa in the log phase of its growth cycle. After 48 h, we counted the adhered cells. We measured the dissolution of HA coating due to bacterial exposure alone by determining the calcium and phosphate concentrations in the bacterial growth media. Once the adherent bacteria were removed from these rods, we subjected them to 5 million cycles of fatigue testing after immersion in Lactated Ringer's solution. We then determined the calcium and phosphate concentrations in the fatigue media. We found additional coating loss after fatiguing of the samples. This coating loss was a cumulative effect of bacterial exposure and fatigue loading of the hydroxyapatite-coated dental implant alloy. The lower crystallinity sample showed a higher loss of coating within the range of crystallinity studied here. The HA coating in implants during clinical use may undergo such changes, because they are exposed to the same bacteria.

Human histologic and histomorphometric analysis comparing OsteoGraf/N with PepGen P-15 in the maxillary sinus elevation procedure: a case report.

The use of the anorganic bovine bone mineral OsteoGraf/N combined with demineralized freeze-dried bone allograft has received widespread use in sinus elevations. This composite graft material has proven to be suitable, predictable, and successful for the placement and integration of endosseous implants in the edentulous, atrophic maxilla. In this case study, the current materials and accepted methodology were compared with the latest tissue-engineered bone replacement graft material, PepGen P-15. PepGen P-15 is a combination of OsteoGraf/N and a synthetic peptide (P-15) that mimics the cell-binding domain of Type-I collagen responsible for cell migration, differentiation, and proliferation. The radiographic, histologic, and histomorphometric evaluations of the sinus grafted with PepGen P-15 showed enhanced bone formation within a shorter time interval compared with the composite graft material of OsteoGraf/N and demineralized freeze-dried bone allograft.

Multi-center clinical evaluation of combination anorganic bovine-derived hydroxyapatite matrix (ABM)/cell binding peptide (P-15) as a bone replacement graft material in human periodontal osseous defects. 6-month results.

A synthetic cell-binding peptide (P-15) combined with anorganic bovine-derived hydroxyapatite bone matrix (ABM) was compared to demineralized freeze-dried bone allograft (DFDBA) and open flap debridement (DEBR) in human periodontal osseous defects in a controlled, monitored, multi-center trial. Following appropriate initial preparation procedures, flap surgery with defect and root debridement was performed. Three osseous defects per patient were treated randomly with one of three procedures after surgical preparation. Appropriate periodontal maintenance schedules were followed, and at 6 to 7 months re-entry flap surgery was performed for documentation and finalization of treatment. Analysis of variation (ANOVA) and t test analyses of patient mean values from 31 patients revealed that the combination ABM/P-15 grafts demonstrated significantly better mean defect fill of 2.8 +/- 1.2 mm (72.3%) versus a mean defect fill of 2.0 +/- 1.4 mm (51.4%) for defects treated with DFDBA (P <0.05) and a mean defect fill of 1.5 +/- 1.3 mm (40.3%) (P <0.05) for defects treated with DEBR. Other hard tissue findings showed similar clinically superior results with the use of ABM/P-15. Relative defect fill results showed 87% positive (50% to 100% defect fill) responses with ABM/P-15, 58% positive responses with DFDBA, and 41% positive responses with DEBR. There were 8 to 9 times more failures (minimal response) with DFDBA and DEBR (26% to 29% frequency) than with ABM/P-15. Soft tissue findings showed no significant differences among treatments except for greater clinical attachment level gain with ABM/P-15 compared to DEBR. These results suggest that the use of the P-15 synthetic cell-binding peptide combined with ABM yields better clinical results than either DFDBA or DEBR. Further studies are needed to determine the relative roles of the ABM and/or the P-15 in these improved results.

Long-term retrospective studies on hydroxyapatite coated endosteal and subperiosteal implants.

This article reports a long-term retrospective study on hydroxyapatite-coated implants, which covers more than 6 years of clinical use. The authors discuss not only cylinder implants, but blade and subperiosteal implants as well. This study reveals that, for the time covered, a definite clinical advantage exists to coating implants with hydroxyapatite.

[Hydroxyapatite coated dental implants. Biological criteria and prosthetic possibilities]. / Implants dentaires recouverts d'une couche d'hydroxyapatite. Critères biologiques et possibilites prothétiques.

Incorporating contemporary implant research and the most advanced principals of biomaterials and bioengineering puts HA-coated implant system into clinical practice. This system utilizes a streamline precision two-stage procedure similar to the swedish method and other osseointegrated systems to ensure complete fixation and an unloaded healing phase prior to the functional use of implants. The surgical concept has been theoretically improved upon by enhancing the titanium cylinders with a HA coating of 50 to 65 microns to the body. The advantages of HA have been extensively discussed. Research has shown that a biochemical reaction occurs between HA and bone and the interface between bone and ceramic is stronger than either the ceramic or bone alone. Bone adapts well to all biocompatible metals and bone will "chemically" bond to HA. An activated sintering process has been developed that enables HA to be chemically bound to the titanium cylinder using a modification of the plasma flame spray technology. This HA coating has been developed to meet the most rigorous biomechanical requirements for bonding in high stress applications of orthopedics as well as intraoral use. Biointegration is defined as "mechanochemical" clinically significant interface that predictably develops between vital load bearing bone and a bioactive calcium-phosphate ceramic metal such as HA. The design and planning of the HA-coated metal system also provides a variety of restorative choices and have been extensively discussed in this article. Clinical reports appear excellent, and the current implant system is into its fifth year of clinical use. The use of HA-coated implants has very well satisfied restorative needs as well as following sound biologic principle.

Hydroxylapatite-coated dental implants. Biologic rationale and surgical technique.

Implant prosthodontics now offers our patients more benefits than conventional prosthetics. Considerations of bone biology, occlusal principles, occlusal materials, implant design, implant biomaterials, patient health profile, patient bone density and quality, site classification, manufacture quality and ethics, and operator efficiency all go into the prognosis and affect our final product. Emerging biomaterials help the clinician, in certain areas, to achieve a more predictable result. The time-tested principle--such as unloaded healing, atraumatic gentle surgical placement, and machined components--are carried along into the new systems that are being developed for clinical use. The use of the HA-coated cylinder has proved to be of extreme value in these past 5 years. It is another step closer to the ideal implant system.