[SunilNagpal]

I always suggest specializations rather than general diplomas/degrees. So, Diploma in Biomedical Science would be a better option than doing a diploma in Biotechnology. In Biomedical you might have to study about Human Anatomy and Physiology, Biomedical Instruments, Nanotechnology, Biosensors, Neurobiology, Pharmaco-Toxicology, Microbiology and Molecular Biology, Physical & Organic Chemistry and some mid-high level mathematics generally.

While Biotechnology being a very broad domain can have anything ranging from Anatomy, Physiology, Microbiology, Molecular Biology, Immunology, Genetic Engineering, Plant and Animal Cell Culture, Bioprocess Engineering, Biomedical Engineering, Pharmaceutical Biotechnology to Bioinformatics, Biochemistry etc

Though general biology would be beneficial at school level for a future dentist career. Biotechnology will also be helpful in understanding the microbial aspects, which are quite closely associated with dental problems.

Biotechnology is "putting Biology into Application" for the welfare of living organisms and the nature!

Bio-engineering is a sub-domain of biotechnology which aims at doing the welfare by developing and launching some tangible biological products (like biofuels, biosensors, biomedical devices, drugs, vaccines). It requires process information, design knowledge, mass/heat transfers etc (the actualization know-how). Researching various sources of biofuels cannot be called Bio-engineering (but it's indeed Biotechnology!), but zeroing on a particular source and developing a process to extract the biofuel is bio-engineering!

Bacteria--> Curd/Yoghurt (you eat it)
Plant-----> Latex Rubber (ancestor of today's forms of rubbers), Taxol (Cancer drug)
Animals---> Antibodies (as medicines against immune disorders, cancers etc), proteins (as drugs) etc

Following should help you:
http://www.amgen.com/pdfs/misc/An_Introd...nology.pdf