There is something wrong with this statement. You are trying to compare the difference in tuition to the amount of money he would earn in the extra year towards the beginning of his career. That is wrong. No matter whether the OP went to a 3 year or a 4 year school, the first few years the OP will earn about the same. Where you have to compare that year to is the income the OP would make at the end of the OP's career.
Here's why I state that. For example: Let's say the OP is 21 now and will be 24 if graduating from a 3yr program and 25 from a 4 yr program. The OP wants to retire at 55 (30 yrs in practice under the 4 yr program and 31 years under the 3 yr program.) Since the OP would graduate form the 4 yr program only a year later, the difference in earnings potential is negligible when comparing when the OP starts the dental career. So, over the 30 years after graduating from the 4 yr and 3 yr, the earnings should be pretty much exactly the same. Under the 4yr program, the OP retires at 55 after 30 yrs. But, under the 3 yr program, the OP is only 54 after 30 yrs. That leaves the OP an extra year to earn money if the OP choses to retire at 55 as the OP chose to do. In 30 years, the average salary (when considering how much salaries have changed over the last 30 years) then will probably be at least between $400,000 and $500,000 per year. After taxes, that would be a whole lot more than the difference in tuition.
Now, you could claim that the cost is about $150,000 more at UoP than UCSF. Where do you get that? I went to both sites just now and totaled up the total estimated expenses they list on the site. The difference comes to Right about $80,000 when you factor everything in including cost of living. One thign that UCSF doesn't factor in is the cost of living for the summer in between the first and second year that you. Therefore, take away about $5,000 from that total. Now, the comparable difference is $75,000. Even if you wanted to use the way you compared how the OP would ean $90,000 after taxes because of graduating one year earlier, the OP is still amking more after taxes than the $75,000. Plus, the OP only had to suffer through 3 yrs of school instead of 4 years. The amount of time that the OP doesn't have to endure the stress should also count a lot. I know I would easily shell out $50-60,000 alone just to be able to get rid of the 4th year of stress.
For the OP - So, basically, with this taken into consideration, don't worry about the cost difference because in the end you have the opportunity to make the cost difference up by working that extra year at the end of your career to retire at the same time you would had you gone to the 4 yr program, or you can just retire a year earlier and be satisfied with paying an extra $75,000 more for the opportunity to get d-school over in 3 years.