What is the reason and timing of deciduous tooth extractions?  An early panoramic radiograph is important to uncover developmental dental problems.  Determining if there are missing teeth allows us to direct them down the proper path for either future restoration or complete space closure.  This gives the child's parent relief that the prognosis for an excellent dental environment is great.  Parents never like to be surprised by the report of missing permanent teeth when their child is expecting eruption of those teeth.  Finding deviant eruption of permanent teeth early allows us to guide these tooth into the proper position thus lessening the amount of future orthodontic movement.  Impacting canines is what we probably see the most. 

Missing Permanent Teeth (Hypodontia/Oligodontia).  Third molars are the teeth found to be most commonly missing (about 23% of the population).  Second premolars are next followed by maxillary lateral incisors.  Keeping mandibular second deciduous molars presents an interesting situation since they tend to be much wider mesio-distally than the underlying premolars (average 1.7mm wider).

Orthodontic intrusion of worn anterior teeth.  I recently had a study club discussion regarding proper positioning of worn anterior teeth in preparation for restorations (crowns, veneers or composite build ups).  Orthodontics is many times necessary for these patients due to the supereruption that occurs as attrition takes place.  We can orthodontically intrude either the upper, lower or all anterior teeth.  I base a lot of this decision on the upper lip to incisor relationship both during rest and smiling.  We also need to take into account the clinical crown length of the worn teeth.  If I can place the teeth in the correct position with proper overjet, a fantastic functional and esthetic result can be had.  These patients refer others to your office since they are walking billboards for your practice.  By the way, we always get before and after photos that you are welcome to use.

 

 

                                     

Quicker turnaround with Invisalign cases.  Now that we utilize digital imaging models for Invisalign cases the time it takes from imaging and records to insertion of the first trays is shortened. Federal Express is quick but the internet transfer is even quicker! The patients appreciate getting started on their treatment sooner since they are excited to see change in their malpositioned teeth. Two weeks from imaging to insertion is very possible!

We all hate impressions!  Our adult and young patients would all tell you that impressions might be what they fear the most at the orthodontist.  We have utilized an I-Cat cone beam scan to gain not only our radiographs but digital models for quite some time.  Recently we have added the new iTero Element visual scanner. We can utilize this for study models, Invisalign treatment, and appliance construction without the need for impressions.  It is much faster than previous models and the images are more universally accepted.  Now we see smiles not only after orthodontics but before as well when they can use the iTero without impressions!

Fluoride Treatment Prior to Orthodontic Bracket Placement.  If you are providing a prophylaxis immediately prior to placement of orthodontic brackets, we suggest not utilizing fluoride at that appointment.  It can weaken the bond strength of the composite leading to brackets dislodging easier.  We always supply the patient with their first bottle of acidulated fluoride rinse at their bonding and ask them to use it nightly throughout treatment.

Lower incisor position and profile changes in extraction treatment.  I am often asked about the effect of upper premolar extraction treatment on the facial profile and many believe that this will significantly retract the upper and lower lip positions.  In most orthodontic cases we must treat the occlusion to the labiolingual position of the lower incisors.  This is because the bone surrounding them is thin both on the facial and lingual aspect of their roots.  If the maxillary anterior teeth are more crowded than the lowers and a class II molar relationship is present, there is usually not a significant overjet.  When upper premolars are removed in these cases the maxillary canines are retracted into the missing premolars' positions and the incisors are uncrowded.  The lower incisors are held in their most stable and healthy location while the overbite and overjet is coordinated to them.  Thus, the profile won't change much and proper canine and incisal guidances are obtained.  Next we'll talk about how the anterior-posterior relationship of the maxilla and mandible relate to profile and incisor angulation. 

Facial profile relationship to extraction treatment.  Facial profile and lip fullness go hand in hand with skeletal and dental positions.  When a thin or retracted lip appearance is present we try our best to treat the patient on a non-extraction basis.  Likewise, when there is a very protrusive lip pattern we consider premolar extractions a bit more often.  If severe crowding is present, extractions will not change the lip pattern much because most of the extraction space is utilized to uncrowd the dentition.  This can be both a blessing and a curse.  In thin lip patterns you will not lose lip support by pursuing extraction orthodontic treatment.  Likewise, with very protrusive lips you will not get as much softening as you might desire.  Another item to consider is the nasolabial angle (angle between the bottom of the nose and upper lip.)  An obtuse nasolabial angle (with upturned nose) requires careful consideration before removing premolars for treatment.  Next week we'll consider the relationship of the lower incisor to facial profile changes.

Indicated extractions in treatment of class II and III malocclusions.  Extraction of premolars may be indicated in order to orthodontically correct malocclusions where growth has ceased and the maxilla and mandible are not matching.  In order to mask a prognathic mandible it is sometimes necessary to remove a lower premolar bilaterally in order to incline the lower incisors lingually and distalize the canines. If we are treating a class II malocclusion without significant lower crowding we can extract two upper premolars in order to gain a tight overjet and class I canines.  With these or any extractions it is wise to take the facial profile into account as we treat the malocclusion.