UCSF

This dissertation uses a flight of analytical approaches to assess the (1) influence of various surgical instruments on post-operative neurosensory deficits (pair-matched double randomized controlled trial); (2) diagnostic determination of osteoporosis using routine dental X-rays (cross-sectional); and (3) association of early life education with lifetime smoking habits across multiple generations from late twentieth century to early twenty-first century (secular trends). Each approach demonstrated its own advantages and challenges, resulting in a range of findings from purely associative to causal. In these three studies, we find that (1) compared to reciprocating saws, ultrasonic surgical instruments result in less inferior alveolar nerve paresthesia in bilateral sagittal split osteotomies, and also that right mandibles are less likely than left mandibles to experience paresthesia in after this surgery; (2) bone mineral density calculated from dental bite-wing X-rays do not determine femoral neck osteoporosis, and are not of clinical or diagnostic use in screening for osteoporosis; and (3) as expected, education has a protective effect on smoking behaviors, however, this effect has been decreasing in magnitude over recent generations, and also, paradoxically, increasing education up to 11 years of education increases the odds of smoking behaviors.