The International Journal of Oral & Maxillofacial Implants, 04/1988

Dental implants vary markedly in the topography of the surfaces that contact cells. Four principles of cell behavior first observed in cell culture explain to some extent the interactions of cells and implants. (1) Contact guidance aligns cells and collagen fibers with fine grooves, such as those produced by machining. (2) Rugophilia describes the tendency of macrophages to prefer rough surfaces. (3) The two-center effect can explain the orientation of soft connective tissue cells and fibers attached to porous surfaces. (4) Haptotaxis may be involved in the formation of capsules around implants with low-energy surfaces. Keywords: cell behavior, dental implants, percutaneous devices, surface topography

When a biological system encounters an implant, reactions are induced at the implant-tissue interface. This article deals with various surface properties that are expected to influence tissue-implant reactions and methods available for implant surface characterization. Surface properties of interest are chemical composition, contamination and cleanliness, microarchitecture and structure, etc. Surface science offers a range of methods for surface characterization, eg, x-ray photoemission spectroscopy (XPS or ESCA) and Auger electron spectroscopy (AES), and preparation, which may be used to optimize implant fabrication with molecular level control. Examples are given from analytical and preparative work by XPS, AES, and electron microscopy on pure and alloyed titanium, with focus on surface oxides on these materials. Results of this type are valuable for basic research concerning implant-tissue reactions as well as production control and implant standardization. Keywords: biomaterial surfaces, implant surfaces, surface analysis, surface preparation, titanium surface

Corticocancellous iliac bone grafts are used to restore mandibular continuity following trauma or tumor ablative surgery. Secondary placement of titanium osseointegrated implants in these bone grafts allows for precise and predictable prosthodontic rehabilitation with a bone-supported prosthesis. This two-stage surgical-prosthetic reconstruction has been accomplished for five patients at the Mayo Clinic. A general review of this series and a detailed presentation of three patients, with follow-up, is provided. Keywords: dental implants, mandibular discontinuity, mandibular reconstruction, oral prosthetic reconstruction

In a study conducted under standardized conditions, 20 ITI hollow basket implants (Type F) were inserted into 10 dog mandibles. The plasma flame-sprayed coatings of the titanium implants that remained in situ or were exfoliated within 32 months were analyzed metallographically and compared with nonplaced implants. Eighty-two percent of the exfoliated retrieved and nonexfoliated implants showed a significantly decreased coating thickness. Fifteen percent of the ITI hollow-basket implants (Type F) fractured. This is in contrast to the behavior of TPS screw implants also examined in this study, none of which fractured. Keywords: animal study, decrease of coating thickness, implant fracture, plasma flame-sprayed coating, titanium implants

Investigations were reviewed to show whether currently available systems (intramobile elements or specially designed suprastructures) had adequate deformability to provide osseointegrated implants with an elasticity imitating the mobility of natural teeth. While the systems tested showed variable deformability, none of them fully met the requirements. This may well explain the funnel-shaped bone resorptions seen in peri implant cortical bone. Keywords: osseointegrated implants, stress-breaking systems, tooth mobility

Ten commercially pure titanium implants were inserted in the mastoid region of the human temporal bone in ten human volunteers and removed by using a torque gauge instrument 3 to 4 months thereafter. The average removal torque of nine implants was 42.7 Ncm with a range of 26 to 60 Ncm. One implant used for histology revealed evidence of bony as well as soft tissue in the interfacial region. Keywords: clinical, osseointegration, removal torque, titanium implant

On June 13-15, 1988, the National Institute of Dental Research (NIDR), in conjunction with the US National Institutes of Health (NIH) Office of Medical Applications of Research and the Food and Drug Administration, held a Consensus Development Conference on Dental Implants. More than 1,000 clinicians, educators, researchers, and administrators attended the conference. A 12-member Consensus Development Panel formed the organization and administrative support for the conference and prepared a consensus statement that responds to five questions addressed by conference participants. The statement is printed here in its entirety for the edification of our readers. - W.R. Laney