Gonadotrophin-inhibitory hormone and its mammalian orthologue RFamide-related peptide-3: Discovery and functional implications for reproduction and stress.

At the turn of the millennium, a neuropeptide with pronounced inhibitory actions on avian pituitary gonadotrophin secretion was identified and named gonadotrophin-inhibitory hormone (GnIH). Across bird species, GnIH acts at the level of the pituitary and the gonadotrophin-releasing hormone (GnRH) neuronal system to inhibit reproduction. Subsequent to this initial discovery, orthologues of GnIH have been identified and characterised across a broad range of species. In many vertebrates, the actions of GnIH and its orthologues serve functional roles analogous to those seen in birds. In other cases, GnIH and its orthologues exhibit more diverse actions dependent on sex, species, season and reproductive condition. The present review highlights the discovery and functional implications of GnIH across species, focusing on research domains in which the significance of this neuropeptide has been explored most.

Experience with ITI osseointegrated implants at five centres in the UK.

Experience with the two-part ITI titanium implant system at five centres in the UK is reported. A total of 461 implants were inserted in 176 patients, who received 189 prostheses. Criteria for the assessment of success following implantation are listed. Results over a 3-year period showed a success rate of 94% when implants were used for mandibular overdentures and crown and bridge prosthetics. A lower success rate in the edentulous maxilla was recorded.

Bar-retained overdentures for implants--technical aspects.

The principles of the laboratory procedures for making overdentures retained by bar abutments on ITI implant fixtures are described, and details of producing the master casts, making a soldered bar, and processing a prosthesis incorporating a cobalt-chromium alloy strengthener are given.

Rat palatal histology related to denture-like appliances.

Two designs of palatal denture-like appliance were fitted to rats. Tooth- and tissue-borne appliances caused changes in epithelial thickness and keratin thickness, but these varied with anatomical site and type of appliance. A single inoculation of Candida albicans at the time of insertion of the appliance failed to establish infection consistently. Debris accumulation under the appliances was a problem which will restrict long-term studies with this model.

The clinical use of ITI transmucosal implants.

The ITI implant system has a background of research and development of over 15 years. It is distinctive in that the implant fixtures are transmucosal from the time of placement, requiring only a single stage in surgical treatment. In a relatively simplified approach to prosthetic management, standard overdenture components and conventional fixed partial denture techniques are used. In this report the assessment, surgical treatment and post-operative management of patients using ITI Bonefit implants are described and early results from 168 consecutive fixtures placed over a period of 3 years indicated.

The persistence of microorganisms on impression materials following disinfection.

Following in vitro inoculation with C albicans or P aeruginosa, three impression materials--polysulfide rubber, irreversible hydrocolloid, and poly(vinyl siloxane)--were disinfected with either 0.1% or 0.02% chlorhexidine gluconate and a quantitative assessment of the microorganisms was made. Very few microorganisms were retained on the poly(vinyl siloxane) material immediately after microbial inoculation. The numbers of microorganisms on polysulfide impression materials diminished rapidly with time even without disinfection, and a 30-minute disinfection procedure resulted in total microbe elimination. With irreversible hydrocolloid, microorganisms persisted and disinfection procedures were considerably less effective. When the disinfection efficacy of three commercially available agents was compared using irreversible hydrocolloid impression material, chlorhexidine gluconate (0.2%) was found to be less effective than either glutaraldehyde (2%) or sodium hypochlorite (0.0125%); the latter two agents were comparable in their antimicrobial effect. Thus, a simple disinfection regime of 30 minutes with commonly available disinfectants may be effective in eliminating cross-contamination from impression materials.

Carriage of oral flora on irreversible hydrocolloid and elastomeric impression materials.

This study assessed the carriage and persistence of oral flora on irreversible hydrocolloid and elastomeric impression materials. In the first part of the study, a single isolate each of Streptococcus mutans, Escherichia coli, Staphylococcus aureus, and Candida albicans were inoculated onto each of two elastomeric and two irreversible hydrocolloid impression surfaces artificially created in vitro. Then the inoculum was discarded, samples of impression material (13 mm in diameter) were removed over a 5-hour period, and the remainder of viable organisms were estimated. In the second part of the study, impressions were made from 21 dentate and eight edentulous patients, and bacterial counts were estimated as described. The results showed twofold to fivefold retention of bacteria on the irreversible hydrocolloids compared with the elastomeric impression surfaces. With all impression materials, the number of viable bacteria retained within 5 hours decreased 65% to 98% except for the "disinfectant" irreversible hydrocolloid Blueprint Asept, which totally destroyed the organisms in less than 3 minutes. It is concluded that the total bacterial "load" on impression surfaces is relatively low and decreases rapidly after impression making. However, disinfection of impression surfaces should be mandatory to prevent cross-infection.

ITI hollow-cylinder and hollow-screw implants: prosthodontic management of edentulous patients using overdentures.

ITI implants, which are transmucosal from the time of placement, require relatively few components or instruments for the procedures involved in prosthetic restoration. The salient features of postsurgical care and management are discussed with respect to treatment of edentulous patients using overdentures retained by retentive anchors and bar attachments.

Histological, microbiological and haematological investigations in denture-induced stomatitis.

Biopsy specimens of palatal mucosa from 10 edentulous female subjects exhibiting the signs of chronic atrophic denture-induced stomatitis were fixed and processed to produce sections which were quantitatively analysed by light microscopy. The type and degree of surface keratinization, the epithelial thickness and basement membrane morphology were assessed. Microbiological and haematological evaluations were related to the histological findings. It was found that within this clinical entity of palatal inflammation there was considerable variation in tissue response at a cellular level, and that the numbers of organisms associated with the inflammatory reaction appeared to be fewer in patients with abnormal haematological status.