This thesis relates to the feasibility of monitoring dental implants using the transmission of Acoustic Emission (AE) from an intra-oral source to a sensor mounted on the patient’s face. A number of in vitro and in vivo experiments have been carried using different AE sources on teeth and dental implants with the ultimate aim of defining the characteristics of the AE signatures in the time- and frequency-domains that are affected by the implant-bone interface. An initial feasibility study was carried out to assess the transmission of simulated AE signals through human teeth and hard and soft tissues by biting on different types of hard food. The tests demonstrated that the transmission of AE signals through human tissues was feasible. However, the source was not reproducible. Further preliminary experiments were carried out to assess the transmission of AE in various dental materials as well as in bone and bone-implant combinations in various states of hydration. The main systematic body of work centred around establishing whether AE signals could discriminate between implants with different amounts of contact with bone. AE signals were generated by applying a standard impulse source through a specially-designed abutment onto dental implants of various sizes (large and small) inserted in bovine ribs under tight and loose fitting conditions. The findings suggested that this simple transmission test was able to assess the quality of the contact between the implant and the bone in the in vitro situation and that it might be possible to extend this to the clinical environment. The (standard) pencil lead break method was not suitable for use intra-orally, so a more suitable source for in vivo testing needed to be developed. After considering various options a continuous source (based on an air jet) was developed and this was applied to dental implants in the same set of systematic tests as for the pencil lead source. The analysis revealed that the air jet source was a little better at discriminating between the various implant contact conditions. Finally, an in vivo study was conducted to assess the characteristics of the transmitted AE form air jet source applied to the dental implants of a number of volunteers. The findings demonstrated that the AE transmission through the implants, soft and hard tissues using an air jet source was feasible, with the degree of transmission depending on a number of variables, some related to the patients themselves and some related to other, tractable engineering factors. The overall conclusion of the work is that the technique is very likely to be successful for monitoring implant stability, and is feasible to apply with minimum invasion to patients whose implants have been newly installed. An in vivo study in which the test is applied to patients during the stages of stabilisation of their implants is required in order to validate the technique.

published_or_final_version / Dentistry / Doctoral / Doctor of Philosophy

No description available.

In this thesis, four experimental studies are reported. Two concern the surface structure of commercially relevant dental implant materials. Characterisation of four treated substrates supplied by Straumann AG was carried out. These include substrates equivalent to the commercially available SLA, SLActive and Roxolid implants. The materials vary in substrate alloy, commercially pure (grade 2) Ti and a TiZr alloy, and surface preparation treatments. All substrates are sandblasted and acid etched however post-etching one set are stored in air whilst the others are stored in saline. Within the work both substrate composition and surface treatment is shown to impact on the respective surface oxide thickness, crystallinity and morphology. The other two experimental studies concern calcium phosphate deposition from solution onto substrates. The first investigation is the deposition of calcium phosphate from a simulated body fluid onto implant-like substrates, shown to be structurally equivalent to the SLA and SLActive implant surfaces. The effect of surface modifications on calcium phosphate deposition is investigated; over the period investigated calcium phosphate did not deposit onto the SLA substrate, whilst deposition occurred within 3 days on the SLActive substrate. The role of Mg2+ ions in the simulated body fluid is also investigated, with increased [Mg2+] resulting in a longer induction period and modified crystallinity of the hydroxyapatite film formed. The final study is a model study of the initial calcium phosphate deposition on to substrates. TiO2 rutile (110) and Al2O3 corundum (0001) were prepared to be atomically flat and then exposed to a simple calcium phosphate solution. Changes in surface structure and surface chemistry over the first three hours of exposure were investigated. Deposition occurred rapidly on both substrates with a complete surface coverage after 3 hours.

Thesis (M.D.S.)--University of Adelaide, 1987. / Typescript. Includes bibliographical references (leaves 131-167).

Diss. (sammanfattning) Göteborg : Göteborgs universitet, 2007. / Härtill 4 uppsatser.

Thesis (doctoral)--Göteborg Universitet, 1993. / Added t.p. with thesis statement inserted. Includes bibliographical references.

Thesis (doctoral)--University of Göteborg, 1993. / Added t.p. with thesis statement inserted. Includes bibliographical references.

Thesis (doctoral)--Göteborg Universitet, 1993. / Added t.p. with thesis statement inserted. Includes bibliographical references.

Thesis (M.D.S.)--University of Hong Kong, 2005.