Orthodontists have the ability to straighten teeth that are severely crowded, rotated and tipped. Excellent orthodontic mechanics can turn a severe malocclusion (bad bite) into a well-functioning, esthetic and long-lasting occlusion.
There are tooth movements, however, that are extremely difficult, if not impossible, for orthodontists to perform without adverse consequences
to other teeth,
a patient's smile and, possibly, a patient's lower facial features. Intruding teeth (pushing them straight into bone) and distalizing teeth (pushing them back in the mouth) are traditionally the two toughest tooth movements to perform. Orthodontists are often left with needing to pursue other treatments to avoid these difficult tooth movements.
Mini-Pins (aka: temporary orthodontic implants, temporary anchorage devices or TADs, miniscrews or microscrews) were introduced in eastern Asia in 1997; they have been used in the United States since ~2001. These titanium pins are placed through the gums into the outer layer of bone, which provides the stability for the pin, so that it can be used to anchor the movement of teeth. These pins are quite easy for the orthodontist or periodontist to place and are nearly painless for the patient, requiring less local anesthesia than required for a simple restoration (filling)! Bone has few, if any, nerves, hence the minimal pain associated with mini-pin placement and subsequent use.
The first set of clinical pictures, above and to the right, show a 16 year-old patient who wanted her teeth straightened, and, specifically,
she wanted her upper left canine tooth moved into its proper position within the dental arch.
She was congenitally missing her upper left lateral incisor and, therefore,
the canine erupted into the lateral incisor position,
leaving the baby tooth in the position where the permanent canine should have ended up. Oftentimes, an orthodontist will leave the canine tooth in the position of the lateral incisor and have a general dentist reduce its size and place a veneer or cosmetic bonding on the tooth to make it look like a lateral incisor. The baby tooth can be left in place until it either exfoliates (falls out) on its own or can be extracted and a fixed partial denture (bridge) or implant placed to fill the space. Due to the difficulty moving canines back in the mouth with traditional orthodontic mechanics, keeping the canine "as is" is probably the easiest and fasted option for all parties involved.
With the advent of mini-pins, the permanent canine tooth can be moved to its proper position, giving what most dentists would agree is the best functional bite and esthetic smile for this patient. A mini-pin is placed just to the upper left of the first premolar and an elastic chain is placed from the pin to a lever arm on the canine. The baby tooth has been extracted and left on the wire, but reduced in width to allow for space to pull the canine to the right (or back in the mouth). Over the course of 7 months, you can see that the canine tooth is being pulled to the right as you look at the teeth(notice the gap between it and the tooth to its left). This is being done without any adverse consequences on the other teeth in the mouth. Normally, an orthodontist would attempt to pull the canine tooth back in the mouth by using other teeth to attach elastics to. These other teeth would also move in response to the forces being placed upon them, and we cannot afford to have this happen in the above patient's mouth. She has a very nice smile to begin with, and we aim to preserve that during her treatment. The last picture shows the completion of canine's movement, at which time a denture tooth was placed to to fill the gap created.
The second set of pictures to the left show a 22 year-old who was congenitally missing a permanent lower second premolar,
and the baby tooth that failed to exfoliate was
seven years following her orthodontic treatment. As a result, her first and second molars tipped forward into the empty space, leaving few restorative options to replace the second premolar. Placing braces on all lower teeth was a treatment option, but the patient declined due to work commitments; she did not want visible braces on her lower front teeth. As a much more conservative and esthetic option, mini-pin placement with only three brackets was used to upright the molar. Treatment was completed in three months, and the patient was extremely happy.
MINI-PINS ARE ONE OF THE MOST SIGNIFICANT CONTRIBUTIONS TO ORTHODONTICS IN THE RECENT PAST. THEY ALLOW ORTHODONTISTS TO COMPLETE TREATMENT ON CERTAIN PATIENTS WITH LESS COMPROMISE AND, THEREFORE, BETTER FINAL RESULTS. THEY ARE NOT INDICATED FOR ALL PATIENTS, BUT, WHEN PROPERLY TREATMENT PLANNED AND USED, THEY ARE A WONDERFUL ADJUNCT TO ORTHODONTIC TREATMENT.