Can people soon grow new teeth?
Stem cell research has produced tangible results for repairing damaged tooth tissue, such as in children treated with stem cells from baby teeth. Growing a completely new tooth in people has not yet been achieved.
Enamel cannot repair itself, and a lost tooth does not normally grow back. Yet researchers have managed to produce enamel-forming cells from stem cells in the laboratory. That is a remarkable step, but it is not yet a treatment: everything happens in the lab, not in a patient's mouth.
There are also promising results in animal studies using stem cells taken from dental pulp, the soft layer on the inside of a tooth, and from the periodontal ligament, the tissue that anchors a tooth in the jaw. Scientists are also gaining a much better understanding of the processes that cause a tooth to form before birth, and are trying to use that knowledge to develop biologically grown replacement teeth. A complete, fully functioning replacement tooth has not yet been achieved in people.
There is one positive result in real patients, but it involves a very specific situation. Children with a damaged permanent tooth received stem cells implanted from their own baby teeth. After twelve months, the dental pulp, including blood vessels and nerves, had measurably grown back, and the root had continued to develop. After two years there were no side effects, but the study included only twenty patients. Moreover, this concerns the repair of a damaged tooth in children with roots that had not yet fully formed, not the growth of a completely new tooth.
Biomaterials used as a scaffold for tooth tissue play a supporting role in this research. Researchers consider root regeneration a somewhat more achievable short-term goal than regenerating an entire tooth, but here too, real-world use is not yet in sight. For anyone who loses a tooth today, an implant remains the best option, or, if the natural tooth can just about be saved, targeted dental treatment.
This answer draws on a study of 26 children on stem cell implantation in damaged teeth, several overview articles on stem cell technology and tissue engineering for tooth regeneration, and one overview article on intentional tooth replantation. The only human study with a positive result is small and limited to a specific situation. For complete tooth regeneration, only laboratory and animal research exists. None of the overview articles combined results statistically; they describe the current state of the field.
Can adults still build bone mass, or only maintain it?
As an adult you can still build bone mass, although the gains are more modest than in earlier life. Strength training, at least three times per week at high intensity, has the best evidence base for this.
Can eating disorders such as anorexia cause lasting bone damage?
Anorexia can cause lasting bone damage, especially when the illness begins during puberty. Early recovery is crucial; speak with your doctor about this if you or someone you know is affected.
Stronger bones and strength training: does it help?
Strength training measurably improves bone density, although the effect remains modest. For the strongest results, high-intensity training under supervision is recommended, even if you already have low bone mass.
Do you really need calcium supplements for strong bones?
Whether you need calcium supplements depends strongly on your age and situation: for healthy women before the menopause there is no evidence of benefit, while women over 50 may benefit from calcium plus vitamin D, provided you weigh the increased risk of kidney stones and the uncertain cardiac risk with your doctor.
Which supplements are proven to help strengthen bones?
For bone strengthening, the combination of calcium and vitamin D is the best supported by evidence, especially in cases of deficiency or elevated fracture risk. Vitamin K2 shows encouraging results in postmenopausal women, but discuss the right dose and combination with your doctor, as too much of any supplement also has downsides.
Can zinc contribute to stronger bones?
Getting enough zinc appears to be good for your bones: people with a low zinc intake are more likely to experience bone loss, and supplementation improves bone density, particularly at the hip. Make sure you get enough zinc every day through your diet or, if that is not possible, a supplement.