This study evaluated differences in dental implant outcomes in patients with osteoporosis and their matched controls. Twenty-four patients, who received dental implants at the University of Toronto, were 60+ yrs and had osteoporosis at the time of implant placement, and their controls matched for age, sex and implant related features were examined clinically and radiographically. Clinical and demographic variables recorded at implant placement and follow-up examination, were analyzed. Implant survival rates of 95.1% and 100%, and success rates of 91.4% and 100% were noted in the osteoporosis and control samples respectively. All failures in the osteoporosis sample occurred in the maxilla of a single subject, raising suspicion that these were related to individual problems specific to this subject. Due to the paucity of adverse outcomes and with all the implant failures having occurred in one subject, no relationship of adverse outcomes with clinical and demographic variables could be analyzed.

published_or_final_version / Dentistry / Master / Master of Dental Surgery

Objectives: The present work was under taken to compare osseointegration of immediately and delayed restored implants in a sheep model, and to compare methods of assessing osseointegration. Methods: Twenty wide-platform implants were placed in the posterior mandibles of 10 sheep, 3 months after premolar extractions. Ten were control implants placed and restored after 3 months of submerged healing. Ten were test implants placed contralaterally and immediately restored. Animals were sacrificed after a further 3 months of healing. At each experimental stage implant stability was measured with resonance frequency analysis (RFA) and standardized radiographs were taken. Tissue blocks with the implants were embedded in acrylic resin. The specimens were analysed by three-dimensional micro tomogram (micro-CT) images. Ground sections of the tissue blocks were then prepared for light microscopy and quantitative morphometry. Morphometric parameters computed by both methods were mean percent bone-to-implant contact (BIC) and mean percent bone density (BD). Radiographic, stability and morphometric measurements were compared statistically. Results: The survival rate was 60% (controls) versus 40% (test) (p=0.28). Mean crestal bone levels after three months restoration did not differ significantly between control (5.54 � 0.92) and test groups (4.35 � 1.61) (p=0.56). All surviving implants were stable at stage three and RFA values in implant stability quotient (ISQ) did not differ significantly between the two groups (test 82.3 � 3.9 versus control 78.8 � 4.3, p=0.36). No correlation was found between crestal bone loss and RFA (Spearman�s rho =-0.27, p=0.46). Histomorphometric analysis found no statistical difference (%BIC test 65.65 � 12.7%, control 53.36 � 6.41%, p=0.18; and %BD test 54.84 � 8.45%, control 64.69 � 13.57%, p=0.11). A similar trend was observed for mean micro-CT (%BIC test 65.72 � 72, control 50.84 � 4.19, p=0.11). Histology revealed high density inflammatory infiltrates beneath the sulcular and pocket epithelium. No significant difference was found between histomorphometric (HMA) and microCT analysis (%BIC p=0.08, %BD p=0.08). A statistically significant correlation was observed between HMA and microCT for %BIC (Spearman�s rho = 0.89, p=0.02) but not %BD (Spearman�s rho = 0.51, p=0.30). Conclusions: The results suggest that the sheep mandibular model has limited potential for evaluation of implants designed for poor quality bone and for the assessment of implant loading protocols. This thesis does highlight the potential for the use of this model in peri-implantitis studies. The results suggest that morphometric variables determined by HMA and microCT analysis are comparable, however further studies are required to standardize the microCT protocol to reduce metal artifacts and enhance bone-implant contrast.

Master of Dental Surgery / This work was digitised and made available on open access by the University of Sydney, Faculty of Dentistry and Sydney eScholarship . It may only be used for the purposes of research and study. Where possible, the Faculty will try to notify the author of this work. If you have any inquiries or issues regarding this work being made available please contact the Sydney eScholarship Repository Coordinator - ses@library.usyd.edu.au

Thesis (M.S.)--University of Tennessee Health Science Center, 2008. / Title from title page screen (viewed on June 10, 2008). Research advisor: Joo Leng Ong, Ph.D. Document formatted into pages (vi, 34 p. : ill.). Vita. Abstract. Includes bibliographical references (p. 31-34).

Thesis (M.S.)--University of Michigan, 1999. / Includes bibliographical references.

Thesis (M.S.)--University of Michigan, 2002. / Includes bibliographical references.

Thesis (M.S.)--University of Michigan, 2002. / Includes bibliographical references.

Thesis (M. Sc.)--McGill University, 1998. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.)--University of Michigan, 1997. / Includes bibliographical references.