published_or_final_version / Dentistry / Doctoral / Doctor of Philosophy

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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.

Introduction: The survival of dental implants depends on osseointegration. Modifications to the implant surface are attractive for promoting the success of the implant. Abrading the surface of the implant with bioactive glass is an attractive option for improving the speed of osseointegration. Aims: To develop a bioactive glass that has the ability to enhance the surface roughness of the implant by embedding particles into the surface and to investigate the effect of grit blast parameters on the removal of the titanium from the surface. Methods: Three glasses based on SiO2-CaO-Na2O-P2O5-CaF2 were synthesized by a melt quench technique. The glasses were characterised and investigated for their bioactivity. Titanium discs were abraded with coarse glass particles by using a grit blast technique with different parameters, such as, distance, air pressure and speed. The depth, width of the abraded line and surface roughness (Ra) were measured by light profilometer. The distribution of the glasses on the titanium surface was measured by SEM-EDX. The biocompatibility of the abraded discs was tested in vitro using MC3T3-E1 cell line. Results: All glasses exhibited an amorphous structure with varied bioactivity. Changing the abrasion parameters influenced the amount of titanium removed and the surface coverage. The harder the glass the lower the amount of titanium removed and the wider the width of the abraded area. The Ra was significantly increased from 0.1μm to 1.6μm. The SEM-EDX analysis confirmed that the glasses were widely distributed and a higher coverage was seen with the harder glass. The abraded discs showed good biocompatibility in vitro. Conclusions: The designed compositions were successfully modifying the surface of the titanium. They are abrasive enough to significantly embed into the titanium surface by using the grit blast technique and increase their surface roughness. TheIntroduction: The survival of dental implants depends on osseointegration. Modifications to the implant surface are attractive for promoting the success of the implant. Abrading the surface of the implant with bioactive glass is an attractive option for improving the speed of osseointegration. Aims: To develop a bioactive glass that has the ability to enhance the surface roughness of the implant by embedding particles into the surface and to investigate the effect of grit blast parameters on the removal of the titanium from the surface. Methods: Three glasses based on SiO2-CaO-Na2O-P2O5-CaF2 were synthesized by a melt quench technique. The glasses were characterised and investigated for their bioactivity. Titanium discs were abraded with coarse glass particles by using a grit blast technique with different parameters, such as, distance, air pressure and speed. The depth, width of the abraded line and surface roughness (Ra) were measured by light profilometer. The distribution of the glasses on the titanium surface was measured by SEM-EDX. The biocompatibility of the abraded discs was tested in vitro using MC3T3-E1 cell line. Results: All glasses exhibited an amorphous structure with varied bioactivity. Changing the abrasion parameters influenced the amount of titanium removed and the surface coverage. The harder the glass the lower the amount of titanium removed and the wider the width of the abraded area. The Ra was significantly increased from 0.1μm to 1.6μm. The SEM-EDX analysis confirmed that the glasses were widely distributed and a higher coverage was seen with the harder glass. The abraded discs showed good biocompatibility in vitro. Conclusions: The designed compositions were successfully modifying the surface of the titanium. They are abrasive enough to significantly embed into the titanium surface by using the grit blast technique and increase their surface roughness. The glass abraded discs show both good bioactivity and biocompatibility in vitro.

The use of antibiotics as prophylaxis against postsurgical infection has been propagated. However, in the field of oral implant dentistry, the use of systemic antibiotics remains a controversial issue, with various antibiotic regimens being advocated. The aims of this multi-center randomized clinical trial were to determine the effect of various systemic antibiotic prophylaxis regimens on patient-centered outcomes and perceptions, postsurgical complications in patients undergoing standard oral implant therapy. In this preliminary study, 107 medically healthy adults who were consecutively admitted to 5 study centers for standard oral implant therapy were randomly assigned to one of the 4 groups (3 test and 1 control groups). Pre-operative antibiotics of 2 g amoxicillin 1 hour prior to standard implant placement were prescribed to test group 1 (positive control), post-operative antibiotics of 2g amoxicillin following implant placement for test group 2, and pre-operative antibiotics of 2g amoxicillin 1 hour prior to standard implant placement and 500mg three times daily on days 2 through 3 after standard implant placement for test group 3. The control group was given a placebo tablet of 2g 1 hour prior to standard implant placement without any antibiotics. Subjects were examined clinically by blinded examiners at 1 week, 2 weeks, 4 weeks and 8 weeks from implant installation for post-operative complications. In addition, Visual Analogue Scales (VAS) on pain, swelling, bruising and bleeding were obtained from the patients from Day 1 through Day 7 and 14. From the results of this preliminary study, in standard single implant placement with non-submerged healing, the postoperative complications (Flap closure, Swelling, Pain, Suppuration and Implant stability) and patient-centered outcomes (VAS of bleeding, pain, swelling and bruising) will neither be affected by using antibiotics prophylaxis in different regimens nor not using antibiotics prophylaxis. It should be reiterated that dental practitioners should be cautious when using antibiotics as a prevention of postoperative infection in dental implant therapy. The indiscriminate use of antibiotics will eventually lead to more serious consequences including allergy and the development of resistance strains. / published_or_final_version / Dental Surgery / Master / Master of Dental Surgery

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 supervisor: Tae-Hong Lim. Includes bibliographic references (p. 47-51).

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