Friday, October 26, 2012

Failure of Permanent Teeth to Grow Into the Mouth Part I

There are two reasons why permanent teeth do not grow in.  Either they are impacted (meaning they cannot grow in because there is insufficient room, or they are growing in a wrong direction), or they are missing.

The presence of only three lower permanent incisors, and no visable lump in the fourth one, might cause you to suspect that one is missing.  X-rays and careful counting will answer this.  An Orthodontist should be consulted immediately because either the impacted tooth will need to be brought in with braces or else the effect of the missing tooth will need to be planned for in the bite.

Similarly, the presence of only two permanent lower incisors while two permanent cuspids are already erupted probably implies the absence of the other two incisors (since there are normally four incisors).  A decision must be made early by an Orthodontist whether to open the space for later replacement of the missing teeth with implants, or to close the space if that would be better.  Space closure might involve substituting the cuspids as lateral incisors, and substituting the first bicuspids as cuspids by partially reshaping them.

If this decision is delayed, or improperly made, excessive protrusion of the upper incisors or excessive vertical overlap of the upper incisors over the lower incisors may result, leading to long orthodontic treatment, and contributing to an unpleasing lip profile.

Thursday, September 13, 2012

Gap Between the Upper and Lower Back Teeth Because the Baby Teeth Stop Erupting While the Face Grows

When a single baby molar appears submerged relative to its neighbors, or when the baby back teeth do not chew against the opposing teeth but are in openbite, you might suspect either that the baby tooth root has frozen to the bone, or else there may be an absent bicuspid underneath.  An x-ray will ascertain if it is a missing permanent tooth,

If a missing permanent tooth is overlooked in the absence of an x-ray, it might be a big mistake to extract the submerged baby tooth, because the resulting space might require a bridge or an implant, or braces to close the space.

On the other hand, if the submerged baby molar is saved into adulthood, and has not submerged too severely, it may recieve a restoration to raise it up to the level of the chewing plane, and be useful for many years.  However, a baby molar that "submerges" early may be too deeply sunken by the relative eruption of the adjacent permanent teeth, to be restorable, and may create such an uncleanable gumline environment for its neighbors that extraction is its eventual best fate.

Since early discovery of a submerged baby molar sometimes means a poor future for that tooth, it is best to involve an orthodontist early in that situation, so that extraction and space closure can be considered.  Another occasional cause of a posterior openbite is a later tongue thrust, where the tongue bulges out sideways and creates a gap between the upper and lower back teeth.  This can be treated with a screen appliance by an orthodontist, and speech therapy to retrain the tongue.

Saturday, June 23, 2012

Premature Loss of a Baby Second Molar

The baby second molar is the most important tooth in the back part of the mouth during the time the permanent teeth are growing in.  These teeth must be preserved until they are pushed out by their replacement teeth (the second bicuspids), because if the baby second molar is lost early, the first permanent molar will drift forward into its space and block eruption of the second bucuspid, and the teeth in front of that site will drift backward, creating an asymmetry in the dental arch.  A space maintainer or a lingual arch retainer wire attached to the permanent molar will prevent this drifting.

If space has already been lost, it should be referred to an orthodontist immediately.  Braces and space opening coils will be placed to re-open the lost space so the second bicuspid can grow in.

Babysecondmolar

Wednesday, April 18, 2012

Premature Loss of a Baby First Molar

If a baby first molar is lost early due to advanced decay, chances are that its replacement permanent tooth (the first bicuspid or premolar) may not be ready to grow in yet.  Some thought must be given to the space resulting from the lost tooth.  If the first permanent molar has already grown in, the missing-baby-tooth space can be left alone because the second baby molar will not usually drift forward.  However, if the first permanent molar has not yet grown in, it may, as it erupts, push the second baby molar into the space of the missing baby first molar, thereby blocking the eruption path and creating crowding of the first bicuspid (the permanent tooth that should replace the missing baby first molar.)

In such a case, a space maintainer attached to the baby second molar is excellent until the first permanent molar erupts.

Babymolarloss

Wednesday, March 14, 2012

Early Loss of a Baby Cuspid on Only One Side

This problem usually happens because of decay of the baby cuspid (not too common) or because of crowding of the permanent incisors (more common), in which the crowded incisors push out a baby cuspid on one side.  This is damaging to the symmetrical development of the dental arch because the incisors then drift into the space of the missing baby cuspid, which blocks the path for the permanent cuspid to erupt, and also shifts the dental midline.  This asymmetry of the dental arch is difficult to correct and requires braces and rubber bands in the front of the mouth.

The proper thing to do when one baby cuspid is lost early is either to regain the lost space immediately with partial braces, or to remove the baby cuspid on the other side of the mouth and then place a lingual arch retainer wire to prevent the incisors from tipping backward from the pressure of the lip.

If a midline shift has already occured, take the child immediately to an orthodontist

Monday, February 6, 2012

Too early loss of both baby cuspids (canines)- this is an often overlooked orthodontic problem.

Frequently, early loss of the lower baby cuspids is a diagnostic sign of (and is caused by) crowded lower permanent incisors (front teeth),  The permanent cuspids will not be able to grow in if their space has already been used by the permanent incisors, which grow in first. If not corrected by an orthodontist, this early crowding may lead to severe permanent teeth crowding, impacted cuspids (unable to grow in), gum recession (lowering), and increase in overbite (vertical overlap of the upper front teeth over the lower front teeth0 and increase in overjet (protrusion of the upper front teeth beyond the lower front teeth), and may cause the need for extraction of permanent teeth later on.

This type of crowding should be reviewed by an orthodontist once the four lower permanent incisors have erupted.  Unless the lip profile (fullness) or gum recession require that teeth be extracted (which is somewhat unusual), early jaw expansion with braces will salvage this crowded condition and avoid later extractions.

Expansion is usually done by widening the dental arch laterally and pushing the incisors forward and the molars backward using braces.  After the treatment, retention is important to prevent collapse of the expansion from cheeck and lip pressure, and it is best done with a semi-permanent wire behind the teeth.

The benefits of early expansion treatment are that extractions of permanent teeth are avoided and more growing time occurs after the expansion, to help stabilize it.  The dental arch and smile have more lateral width, which looks better.

Crowding involving significant loss of the lower baby cuspid space is a condition that worsens with time.  It is not advisable to "wait and see."  This space needs to be regained early with active therapy.

Earlylossofcuspids

Monday, January 23, 2012

Do your upper gums display too much? An Orthodontist can advise you how to improve it.

This is very displeasing to the eye and is due to over eruption of the upper front teeth and jaw.  To make it look better, the upper teeth need to be intruded (pushed upward into their sockets), or the upper jaw may need to be pushed upward.  As the teeth move upward, the bone and gums remodel and the smile looks much nicer