Truth Telling about Tooth Whitening

Dr. Van Haywood is a nationally known expert on tooth whitening currently on the faculty at the College of Dental Medicine, University of Georgia. With over 20 years of experience both in research and clinically on patients, his opinions with respect to which products and techniques work best should be of interest to those considering tooth whitening. Before beginning any such procedure, he recommends a complete dental exam by a dentist complete with radiographs (x-rays) so a diagnosis of the cause of discoloration can be made and pathology ruled out.

Many over the counter products such as Crest Whitestrips contain hydrogen peroxide (HP) rather than carbamide peroxide (CP) generally utilized by dentists. Both whiten by oxygenating the tooth though sensitivity with the former is about three times greater than with the latter. For patients unable to tolerate such sensitivity, the use of toothpastes with 5% potassium nitrate and NOT containing sodium lauryl sulfate (SLS) for 2 weeks ahead of whitening may be quite effective in reducing discomfort. Additionally, placing such toothpastes (Sensodyne Pronamel for example) in the whitening tray 30 minutes before using the whitening agent will likely reduce sensitivity further. Dr. Haywood favors 10% CP because it has NOT been shown to damage the teeth or the gums even with prolonged use of many months and has been shown to be effective. Avoidance of acidic ( low ph) foods like soda, juices, wine and yogurt before and after whitening also can reduce sensitivity.

The more whitening that needs to be achieved, the longer it will take….many months in some cases. Patients with tetracycline staining for example may require 9 months or longer of nightly whitening effort! In office one time use of higher concentration products does not appreciably change the time factor required to achieve whitening nor has it been shown that adding heat, light or lasers to the process makes much difference.

For patients with recurrent apthous ulcers (canker sores), Dr. Haywood suggests trying SLS free toothpastes (read the label!). Interestingly, 7 nights of 10% CP use is about equivalent to 16 days of Crest Whitestrips (6.5% HP). When comparing the cost of even prolonged home use of CP over many months with veneers or crowns, whitening is considerably more cost effective when successful.

Finally in orthodontic patients, the use of 10% CP can whiten teeth even with the braces remaining since the agent disperses all around the tooth AND under brackets within 10 minutes. Further, CP is an antiseptic (antibacterial) which is useful in orthodontic patients with gum inflammation and is also cariostatic (inhibits cavity formation) to a greater degree than chlorhexidene (Peridex for example). The use of CP in orthodontic patients with less than ideal hygiene appears to be justified according to Dr. Haywood.

 

Update on research comparing self-ligating and conventional braces

 

Conventional braces (CB) require a wire ligature or plastic O-ring to engage and hold the archwires in place while self ligating braces (SLB) have an internal locking mechanism replacing the need to change O’s at each appointment. Much continues to be made in the popular literature and on the Internet about the increased efficiency and speed of SLB therapy as well as the decreased duration as compared to CB therapy.

Most bracket manufacturers have both types of bracket lines to sell . A randomized controlled study appearing in the June 2010 American Journal of Orthodontics by Fleming, DiBiase and Lee appears to set this notion to rest. 66 consecutively treated patients were randomly assigned to one of two such systems (CB or SLB) marketed by 3M Unitek. Results were analyzed for several parameters including speed, accuracy and efficiency of each approach. The conclusion: SLB’s “neither improved the efficiency…nor resulted in fewer treatment visits” as compared to CB’s. Several other recent studies support these findings. We note that the cost of SLB’s is 5-10 times greater per bracket than CB’s and users report trouble finishing cases due to failures or jamming of the locking mechanism for the archwire in the latter stages of therapy.

 

 

Mysteries of Root Resorption during Orthodontic Treatment
 

One unfortunate potential complication of orthodontic treatment is shortening of the roots which results in less future support of the affected tooth (teeth). The process is not pain inducing, cannot be predicted or prevented and despite decades of investigation it remains unclear just why it occurs in some patients but not in others. In 28 years of practice we have never lost a tooth to root resorption but we have seen diminished support for affected teeth. If short roots on the front teeth are detected pretreatment, it may be prudent to followup with additional imaging 6 months later to look for additional changes though one must take into account the additional radiation administered to the patient and the likelihood ( very small ) that a change will be found sufficient to justify a change in the treatment plan. The standard of care in these situations has not been established but in general, we avoid obtaining x-rays to look for problems we’re unlikely to find and even if we did would not often result in a change of treatment. The research article on resorption by Marques, Ramos-Jorge,Armond and Ruellas appears in the American Journal of Orthodontics 2010; 137:384-8

 

 

Effectiveness of Bonded Orthodontic Retainers

Ziman Orthodontics has been a proponent of post-treatment bonded retainers placed behind and individually attached to the upper and lower front six teeth for some 20 years. Our website at www.DrZiman.com has many such examples of our cases. With few exceptions, we believe that they represent the best solution for maintaining long term stability. Additional clear removable retainers are provided to be worn nightly.

In the May 2011 issue of the American Journal of Orthodontics appears a study by Renkema, Renkema, Bronkhorst and Katsaros consisting of 221 consecutively treated patients who had lower bonded retainers placed after completion of their treatments and were then followed to assess relapse for 5 years. Statistical results were highly significant using the “irregularity index” analysis which measures the pre-treatment degree of crowding thereby allowing for post-treatment comparisons years later. Excellent stability in 91% of the cases at 5 years was observed while the rest had slight movements correlated to breakage of the retainer which was subsequently repaired…movement likely occurred in the time interval between the breakage and repair. Other studies have compared breakage rates of bonded retainers attached to just the cuspids (2 teeth) versus the front six teeth (cuspids and incisors) as we do with more breakage observed in the former retainer. The evidence based rationale for using bonded retainers is very convincing in our judgement taken together with our clinical observation that fully half of our adult cases are retreatments (not ours) where bonded retention was not used and the front teeth moved.

There are concerns by some about the increased difficulty of flossing and oral hygiene maintenance associated with the use of bonded retainers. They need to be balanced by the overwhelming benefits of maintaining stable post-orthodontic results which avoid retreatment later in life. We tell our patients that the price of stability is nightly flossing under the bonded retainer(s). Most gladly accept that tradeoff. Lately we have been recommending a product by the GUM brand called “Softpicks” which provide both cleaning of the area under the bonded retainer between the front teeth and stimulation of the gums as well without the need to thread floss under the retainer.

 

 

Tongue Thrusting, Open Bites And Orthodontic Treatment

 In the May 2010 issue of The American Journal of Orthodontics appears a study by Smithpeter and Covell which analyzes the relationship between orthodontic patients who tongue thrust and open bite of the front teeth. In this context , “ open bite “ means the front teeth are apart when the back teeth bite. Vertical overlap of the front teeth is termed “ overbite “ whereas “ open bite “ ( also termed “ reverse overbite “ )  can be related to a growth discrepancy of the jaws and/ or tongue thrusting. When swallowing or at rest, the tongue should NOT be positioned between the front teeth.

We have seen open bites in the front and / or on one or both sides. Relapse or recurrence after orthodontic treatment does happen even when jaw surgery has been undertaken in conjunction with braces. There seems to be a correlation among tongue thrusting, mouth breathing, nasal airway obstruction, narrow upper jaws with crossbite tendencies and open bites though this study speaks only to thrusting and open bites.

In this study, 76 orthodontic patients with open bites 27 of whom ( experimental group) received myofunctional therapy (tongue placement therapy) before, during or after their braces and 49 of whom did not (control group )  were compared with respect to how well their cases stabilized after treatment. The differences were highly statistically significant and as we would predict, those who underwent therapy were more stable.

What does this mean for patients?

1. Tongue placement issues can effect dental development and even the shape of the arches

2. Early intervention is warranted in an effort to prevent serious bite issues later on

3. Intervention with a myofunctional therapist or MFT ( in our experience a speech therapist with specialized training) and/ or the orthodontist ( appliance based therapy or APT) may be indicated
   
   MFT is subjective by nature. Younger patients seem to do better with APT though it provides only for negative reinforcement while MFT holds open the possibility of retraining tongue position . Unfortunately, relapse of the thrusting can unpredictably occur with either approach and should be continually monitored after treatment for years. In our practice, we sometimes design special removable retainers fitted with prongs to “remind” the tongue to stay away from the teeth. They are generally effective if worn as prescribed. Additionally, while we avoid removable retainer wear during the day in favor of bonded retainers ( check out our website for examples and details), in thrusting patients we sometimes design a removable palatal stent to maintain the width of the upper jaw.
   
   When allergy or nasal airway obstruction ( enlarged tonsils, adenoids, turbinates or deviated septums for example) may be contributing factors to thrusting or mouth breathing, referral to an allergist or ENT physician may be indicated. Such interdisciplinary management can be challenging to maintain as not all healthcare providers are familiar with the interrelationships that exist with dental development and may require additional explanation from the orthodontist. Interestingly, some orthodontists also do not recognize these factors and fail to account for them in treatment planning their cases. This study should reorient their thinking.
   
   At Ziman Orthodontics we are always asking ourselves why a patients case looks the way it does and tongue thrusting is always in the backs of our minds when we see open bites. We have routinely referred to myofunctional therapists when indicated for over 20 years along with specialty referral as needed.

 

Self Ligating Braces
 

Self ligating braces as a new technology have previously been reviewed under our “ New Technologies “ category. In the May 2009 American Journal of Orthodontics, authors Fleming, DiBase, Sarri and Lee compared the efficiency of aligning crowded lower front teeth on 66 consecutive patients using either conventional or self ligating braces from the same manufacturer. Results indicated that the efficiency of tooth movement was independent of bracket type. In other words, neither bracket demonstrated a superior ability to speed up treatment in these cases. It should be noted that per bracket cost of self ligating braces are 5-9 times that of conventional braces.

My own experience with self ligating brackets was somewhat frustrating in that over time, the engagement mechanism becomes looser and / or sticky with plaque, calculus and food debris making the insertion of the largest archwires needed to finalize the case problematic. In some cases, selected brackets required replacement near the end of treatment which is exactly what one does NOT want to be doing when attempting to finish up a case and is definitely not a timesaver.