The International Journal of Oral & Maxillofacial Implants, 01/1989

A new endosseous titanium implant has been designed to replace skin adhesives as a method of retention of maxillofacial prostheses. The effects of various methods of preimplantation preparation on surface characteristics of the implant were analyzed with electron spectroscopy for chemical analysis. Having undergone one of several pretreatment protocols, fixtures were implanted in the crania of Yucatan miniature hairless swine. Both argon radiofrequency glow discharge and ultraviolet chamber treated implants were associated with the rapid ingrowth and maturation of new bone around the fixture. Conventional steam sterilization was associated with a paucity of neo-osteogenesis accompanied by the production of thick collagen slings at the interface. Apparently, the bulk material, fixture design, and method of surface preparation all contribute to the ultimate clinical fate of an implant. Keywords: endosseous titanium implant, radiofrequency glow discharge, ultraviolet

Insufficient bone volume may be a significant problem in connection with dental implants. In this study, a technique based on the principle of guided tissue regeneration was tested for its ability to generate bone tissue around titanium implants. Implants were inserted in tibiae of rabbits. To create a secluded space for osteogenesis and to prevent soft tissue ingrowth, a porous Teflon membrane was placed around exposed parts of the implant. Where a membrane had been used, the threads of the implant were completely covered with significant amounts of new bone. This study indicates that the membrane technique is a reconstructive surgical method that may be applicable to create new bone around exposed parts of titanium implants in a clinical setting. Keywords: bone regeneration, osteogenesis, Teflon membrane, titanium implant

This study examined the initial attachment of Streptococcus sanguis G9-B and Actinomyces viscosus T14V to saliva-treated powdered enamel and titanium surfaces. Using an in vitro adherence model, significantly lower numbers of Actinomyces viscosus T14V bound to the saliva-treated titanium surface when compared to that of the similarly treated enamel. The binding of Streptococcus sanguis G9-B to titanium or enamel did not vary significantly. A comparison of the percentage of cells bound to the titanium surface revealed that S sanguis cells attached in significantly higher numbers when compared to the A viscosus cells. Keywords: Actinomyces, adherence, Streptococcus, titanium

Creating a predictably passive fit of long-span castings supported by osseointegrated implants can be a difficult technical accomplishment. A preliminary report of short-term experience using a modified casting technique that incorporates several new modifications to ensure fit and accuracy is presented. This technique ensures strength in areas where stress concentrations are greatest while maintaining the philosophy of stress distribution through splinting across the length of the span. Keywords: cantilever strength, passive fit, single-piece casting

Ridge mapping is a measurement procedure to ensure that the diameter of an endosseous screw implant does not exceed the dimensions of available bone. The long-term success of implants is a prime aim. To achieve this, it is essential for the initial evaluation of the dimensions of the resorbing alveolar process to be absolutely accurate. Ideally, an implant should be covered by at least 1 mm of bone on all sides. The major problem is estimating the thickness of bone, since the mucosal contour can mask the actual dimension of the alveolar ridge. Use of ridge mapping with the Wilson Bone Caliper makes possible a reliable evaluation procedure at the initial stage of treatment planning. Keywords: bone dimension, implants, ridge mapping

The vital microscopic chamber is an experimental implant of commercially pure titanium that admits in vivo and in situ observations of bone vascularity and bone remodeling. The bone growth chamber and the bone harvest chamber, in particular, are useful tools for quantifying bone regeneration under the most variable experimental conditions. Keywords: bone regeneration, bone vascularization, microradiography, titanium implant, vital microscopy

Naturally occurring axially directed closing and chewing forces were measured in ten patients with mandibular fixture-supported cross arch prostheses occluding with maxillary complete dentures. The design of the mandibular constructions was characterized by bilateral posterior two-unit cantilevers. The forces were measured using eight miniature strain gauge transducers mounted in the maxillary denture and evenly distributed over the tooth arch. Forces were thus measured at four occlusal contact points over the fixture segment and over each of the four posterior cantilever units simultaneously, giving a detailed picture of the force distribution. The total forces developed during maximal closing in habitual occlusion and chewing were of the same magnitude as previously reported for patients with tooth-supported cross-arch fixed partial dentures occluding with natural teeth using the same method. Contradictory to previous findings, in dentitions with comparable tooth supported cantilever constructions occluding with natural teeth, local closing and chewing forces increased bilaterally in the distal direction. On average, 70% of the forces were borne by the cantilevers and 30% by the fixture-supported segment of the prostheses. Keywords: complete dentures, implant supported prostheses, occlusal forces

A retrieval study of a hydroxyapatite-coated subperiosteal implant after 1 year of function, demonstrates a direct connection with the underlying bone. Keywords: fluorescent activity, hydroxyapatite (HA), subperiosteal implant