Background: A number of systematic reviews provide the basis for decision-making in treatment planning of the reconstruction of mutilated dentitions. This includes identifying teeth difficult to treat/save and decisions on replacement such teeth if extracted. Aims: 1) To assess attitudes of general dental practitioners (GDPs) in a community where provision of dental implants is a widely practiced treatment; and to determine variations in attitudes with respect to dentists’ factors, training factors and implant-provision factors (Study 1): and 2) To determine treatment decision making with respect to maintaining periodontally compromised teeth among dentists with and without postgraduate qualifications in implant dentistry (Study 2). Methods: Study 1:A cross-sectional survey was conducted on a random sample of registered dentists in Hong Kong regarding their attitudes towards implant dentistry with respect to (1) perceived superiority, (2) perceived outcomes, (3) perceived complications and maintenance issues and (4) placement issues. In addition, information was collected on dentists’ factors, training factors and implant provision factors. Variations in attitudes towards implant dentistry were explored. Study 2: A series ofpatient scenarios with varying degrees of periodontal disease levels was presented to selected dentists. Information on their decision-making outcomes, and their intention to retain compromised teeth was analysed in bivariate and regression analyses; accounting for postgraduate implant training, gender, years in dental practice and implant placement experience. Results: Study 1: Among eligible practitioners (n=246), the response rate was 46.3%. Most dentists’perceived implants to be superior to conventional prostheses for the replacement of a single missing posterior tooth (80%) and likewise, for the replacement of a single missing anterior tooth (67%). Variations in attitudes existed with respect to dentists’ factors: years in practice (p<0.05), place of graduation (p<0.05); implant training factors (p<0.05), number of days of training (p<0.05) and implant experience factors (p<0.05). Study 2:This study involved 30 dentists with postgraduate implant qualifications (GDPP), 33 dentists without postgraduate implant qualifications (GDP) and 27 dentists undergoing postgraduate training for implant qualifications (GDPT). Variations in treatment decision-making were evident between the three groups (p<0.05). Differences in treatment approaches to retaining compromised teeth were apparent(p<0.05). Furthermore, variations in rehabilitation of extracted scenarios existed in terms of use of implants and number of implants needed for rehabilitation. Accounting for dentist and practice factors in regression analyses, compared to GDP, GDPP/GDPT were three times as likely to retain periodontally compromised upper molars with painwith pain (OR 3.08, 95%CI 1.09, 8.14 p=0.03), or without pain (OR 3.10, 95%CI 1.04, 10.62 p=0.04). Conclusions: Study 1:In a community where provision of dental implants is widespread the attitudes of GDPs are not wholly in line with evidence-based knowledge. Variations in their attitudes exist with respect to dentist factors, training and experience issues. Study 2: Variations in treatment decision making with respect to retaining periodontally compromised teeth exist between dentists with and dentists without postgraduate training in implant dentistry. Furthermore, there are differences in their management approaches. / published_or_final_version / Dentistry / Master / Master of Philosophy