Editorial. The seventies and beyond.
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Dentistry↗
Biomedical subjects
F T Lake
Publications and source records attributed to F T Lake.
Bioelectric potentials associated with the growing deer antler.
Bioelectric potentials associated with the developing deer antler throughout its growth cycle can be correlated with the rate of longitudinal bone growth. Electrodes were connected to a high input impediance microvoltmeter, and potentials on the surface of antlers of mature deer were measured during the antler growth cycle. The reference electrode was placed at the base of the antler, while the recording electrode was placed at the antler tip or along the antler shaft. Antler length measurements were made during the growth cycle and longitudinal growth rates were determined. Growth rates and bioelectric potentials were compared for three specified periods during the antler growth cycle. The most negative potential was recorded from the antler tip. Furthermore, electronegativity increased as the rate of growth in length increased and decreased as the rate of growth in length decreased. The potentials reached isopolarity at the end of antler growth.
Action Potentials↗
A comparative investigation in dogs: 2-year morphometric results of the dental implant--bone interface.
One hundred twenty titanium and ceramic root-form and titanium blade implants were placed into 30 dog mandibles. Twenty-four implants in six control dogs (in situ for 5 months) did not receive prostheses. Ninety-six implants in 24 dogs supported prostheses for 6, 12, 18, or 24 months. Computerized morphometry data presented the percent of the implant surface apposed directly by bone. A three-way factorial analysis of variance was used to assess significance. Individual implant means ranged from 0% (mobile implant) to 71% bone adaptation. From these data, two-stage titanium root-form implants were shown to be apposed by more bone than the other five systems, and overall, titanium implant systems were apposed by more bone than ceramic systems. Between 41% and 50% of the surface of integrated ceramic implants were apposed by bone, whereas between 50% and 65% of the surfaces of titanium implants were apposed by bone. Also, two-stage surgery for blade implants appears important for implant success. Furthermore, the use of Nomarski differential illumination appears to be useful for examining the quality of interfacial bone to correlate with the amount of bone quantified by morphometric protocols.
Analysis of Variance↗
Composite morphology of the bone and associated support-tissue interfaces to osseointegrated dental implants: TEM and HVEM analyses.
Correlated transmission electron and high-voltage electron microscopic analyses examined the undecalcified bone and associated support tissues of 60 endosseous titanium blade and titanium and ceramic root-form implants in dogs. The implants supported fixed partial dentures for up to 2 years. Data obtained from this investigation suggest that a range of tissues, both mineralized and unmineralized, support osseointegrated dental implants. This study examined the tissues apposing not just isolated aspects of the implant surface, but the entire length of the implant, and found that mineralized and unmineralized tissues existed concurrently. Much of the implant surface was apposed by mandibular bone, and both root-form and blade implants osseointegrated. The densely mineralized collagen fibril matrix was often separated from the implant by only a 20-nm to 50-nm electron-dense, ruthenium-positive deposit. High-voltage electron microscope stereology demonstrated that cellular processes extended directly to the implant from underlying osteocytes. In the same implants, areas containing an unmineralized collagen matrix interposed between the bone and implant surface were observed. In this region osteoblasts interacted with this matrix, and Howship's lacunae, containing vascular elements and osteoclasts, were also observed. The remodeling activities appear to be a homeostasis of catabolic activity (osteoclasts) and metabolic activity (osteoblasts). The apex of the implant was often apposed by a fibrofatty stroma. The support tissue response appears to be the result of the interrelations of osteoblasts, osteocytes, and osteoclasts in association with vascular elements. Therefore, the support tissue response to osseointegrated implants is a dynamic activity that involves the healthy interaction of these cells and tissues along the entire length of the implant.
Adipose Tissue↗