Sempre più partecipanti !!!
venerdì 3 dicembre 2010
giovedì 4 novembre 2010
La stabilità ...
JCO INTERVIEWS
Dr. Robert M. Little on
the University of Washington
Post-Retention Studies
DR. SINCLAIR Would you describe for our
readers the source of the unique University of
Washington post-retention sample?
DR. LITTLE My teacher, mentor, and good
friend Dick Riedel had the idea of recalling his
own ABO cases to see how they fared years later.
He learned so much that he decided to expand the
search to as many of his former patients as he
could locate. While chair of the UW Department
of Orthodontics, Dick broadened the search to
cases treated by our graduate students. Faculty,
alumni, and other orthodontic colleagues contrib-
Dr. Sinclair Dr. Little
Dr. Little retired as a Professor Emeritus, Department of Orthodontics,
University of Washington, Seattle, and continues to teach and lecture.
E-mail him at bobvallittle@msn.com. Dr. Sinclair is an Associate
Editor of the Journal of Clinical Orthodontics and a Professor,
Department of Craniofacial Science and Therapeutics, School of
Dentistry, University of Southern California, Los Angeles; e-mail:
sinclair@usc.edu. A related article on the University of Washington
studies appeared in the October 2009 issue of JCO.
uted cases from their own practices. The result is
about 900 sets of long-term post-retention records,
about one-fourth of the cases having been treated
by UW graduate students.
DR. SINCLAIR Are there clinical procedures
that can improve stability?
DR. LITTLE As I mentioned in last month’s
article, space maintenance during the mixed dentition
for cases with enough leeway space to counter
the degree of anterior crowding is an excellent
way to improve stability for cases that qualify. It
is necessary to do an arch-length assessment by
measuring erupted and unerupted canines and
premolars, using accurate radiographs and casts.
If leeway space is favorable, space maintenance
can shift a potential extraction case to a nonextraction
plan in the permanent dentition without arch
development. The success rate is much higher,
upwards of 70% success post-retention. For cases
with inadequate leeway space for this approach,
either extraction or arch enlargement would be
considered.
Unfortunately, both extraction and nonextraction
enlargement strategies yield poor success
post-retention, with extraction cases faring better
than arch-development cases. For improved stability,
routine mandibular arch treatment should focus
on not enlarging and not changing the arch shape.
Maintaining the original upper and lower incisor
angulations or adjusting them to standard norms
would be additional goals.
In almost all cases with generalized spacing,
VOLUME XLIII NUMBER 11 © 2009 JCO, Inc.
JCO INTERVIEWS
discontinuing fixed retention after a few years
would be fine. For crowded and extracted cases,
we can’t predict which cases will fail, so lifetime
retention seems prudent. For nonextraction treatment
of crowded cases, lifetime retention is mandatory,
since anything less will predictably fail.
Serial extraction of premolars typically improves
alignment during the observation phase,
with a simpler full-treatment phase to follow.
Unfortunately, long-term alignment success is no
better than the 30% success rate of premolar
extraction cases treated in one phase.
Supracrestal fiberotomy (sulcus slice) is useful
to reduce the percentage of rotational relapse,
but does not eliminate all rotational relapse. Interproximal
stripping to flatten contacts does not
seem to aid stability, nor does reducing incisor
width to meet Peck and Peck labiolingual vs.
mesiodistal dimension standards.1 Stripping either
or both arches to meet Bolton tooth-size norms
can be warranted to meet overbite/overjet/occlusion
goals, but this will not necessarily improve
the stability of alignment.
Finally, fixed mandibular retention is much
preferred over removable retainers to ensure that
the retainer is faithfully utilized. Patients need to
understand that they are at risk if the fixed retainer
becomes disconnected. The patient should be
advised to have it reattached as soon as possible.
DR. SINCLAIR What other retention rules do
you suggest clinicians should follow?
DR. LITTLE Always obtain and maintain pretreatment
and end-of-active-treatment records for
future review. These will be quite helpful in guiding
the retention and post-retention phase. Pretreatment,
perform a Bolton tooth-size analysis for
every case and record this information in the chart.
A patient with significant discrepancy requires a
lab wax setup in order to visualize the problems
and treatment needed. Obtain cephalometric and
panoramic radiographs during treatment to assess
progress, growth, and the need for treatment
alteration toward the intended goal. Cephalometric
superimposition is critical to fully understand
treatment progress.
Employ supracrestal fiberotomy for incisor
rotations noted before treatment.
Continue to see your patients following treatment.
This may mean every three to six months
for several years, and then yearly thereafter. The
retainer status needs to be checked, as do signs of
relapse. Be available to counsel your patients.
Facilitate interaction with the patient’s general
dentist, so that the generalist and hygienist do
not remove the fixed retainer. Encourage them to
send the patient back for repairs. Dialogue with the
patient’s dental team of professionals so that all
are aware of your goals and concerns.
Advise the use of lower-arch fixed retention
rather than removable retention to eliminate compliance
as an issue. Utilize upper removable retainers
full-time for a number of months after treatment—
usually a year in my cases—followed by
continued use on a declining scale until some
minimum is established, such as once a week for
an extended time.
Only proceed from active treatment to retention
when the very highest treatment standard
attainable has been met. Assume that every case
is a future ABO case, and treat to that standard.
DR. SINCLAIR How do you advise retaining
deep-bite and open-bite cases?
DR. LITTLE Retention of the deep-overbite case
can be a challenge, particularly for the growing
patient. I overtreat to about 10% overbite and follow
with a flat-biteplate removable upper retainer
with a circumferential labial/buccal wire. The
biteplate is trimmed so that canines and posteriors
are in full occlusion, while the lower incisors just
make even contact with the biteplate and lingual
surfaces of the upper incisors. Six to 12 months of
full-time upper retainer wear is recommended,
followed by nightly wear.
Retention of open-bite cases in growing
individuals is even more of a challenge. Certainly,
overtreating to about a 30% or greater overbite is
the goal, if it can be attained. Many practitioners,
including myself, follow that plan with all sorts of
gadgets or spurs added to resist tongue interference.
I recall a number of growing open-bite
JCO/NOVEMBER 2009
Dr. Robert M. Little
patients with a vertical growth direction who benefitted
from posterior high-pull headgear during
treatment and retention.
DR. SINCLAIR Should retention be different for
adults vs. children?
DR. LITTLE In my view, the retention strategy
should be the same. I am humbled by my inability
to predict post-retention changes. I can’t reliably
predict the post-retention successful cases or the
ones that will fail, whether treated as an adult or
a child. My best defense is the highest-quality
treatment that I can achieve, followed by lifetime
retention.
Adults seem to have a few unique problems,
such as slight space reopening in extraction sites.
This may be due to non-parallel roots of teeth
adjacent to the extraction sites; it can also be due
to excessively rapid space closure. Cases with
inflamed gingivae seem to also have this problem.
Improved oral hygiene, such as the use of a waterirrigation
device during treatment, and other periodontal
strategies should be considered. In some
cases, the reason for space reopening may be
unclear. My strategy for the case with parallel
roots, but space tending to reopen during retention,
is to reclose the space and bond a buccal wire to
the teeth adjacent to the space, with that wire
removed six months later.
DR. SINCLAIR Is there a relapse risk profile that
might help us identify patients at the highest and
lowest risk of relapse?
DR. LITTLE A patient who has adequate or excess
arch length in the mixed or permanent dentition is
in the low-risk category. Those with inadequate
arch length and crowding before treatment are in
the high-risk category, no matter what the treatment.
Those crowded cases treated with arch
enlargement in the mixed or permanent dentition
are in the very high-risk category. Mixed dentition
arch development routinely fails if the lower retainer
is removed. Permanent dentition arch development
is also a very high-risk strategy. Lifetime
fixed retention is mandatory for such cases.
When comparing our best and worst UW
post-retention cases treated in the permanent dentition,
several items stood out as risk factors: pretreatment
high PAR score, pretreatment crowding,
active post-treatment growth, males, and Class II
malocclusion.
DR. SINCLAIR When is extraction treatment a
more stable choice than nonextraction therapy?
DR. LITTLE Nonextraction arch development in
crowded cases almost guarantees instability. Extraction
of first premolars in crowded cases gives
variable results, about 30% having success 10
years post-retention. Second premolar extraction
yields similar results. Serial extraction can make
the case easier to treat, but stability is no better
than in cases that are extracted and treated in the
full permanent dentition.
For the unique, very crowded case where
tooth size permits extraction of either one or two
lower incisors rather than premolars, the postretention
scores are much improved (Figs. 1,2). In
fact, incisor extraction cases as a group were far
better than crowded and premolar-extracted cases
and approached the long-term quality level of
spaced or adequate-arch-length cases.
DR. SINCLAIR What about the Damon approach
to treatment?
DR. LITTLE Dwight Damon and I were classmates
in the University of Washington orthodontic
class of 1970. Nonextraction enlargement of arches
for crowded cases was as far from the philosophy
of that time as one could imagine, our school
being a Tweed-influenced faculty. If a case was
crowded, extraction of premolars was the standard
plan. Enlargement of the crowded arch was reluctantly
used for the occasional case where there was
a concern about facial profile.
We have looked at the degree of arch-width
and arch-length enlargement shown on plaster
casts in Damon-philosophy-treated crowded cases,
as well as cephalometric changes during treatment,
such as flaring of anteriors to achieve alignment.
The amount of arch-width and -length enlargement
and flaring of anteriors was impressive in many
cases, but what about stability? All of the cases
VOLUME XLIII NUMBER 11
JCO INTERVIEWS
A B C
Fig. 1 A. 29-year-old patient before treatment. B. After 28 months of active treatment, with one incisor
extracted. C. Good alignment 10 years after retention (age 42).
had permanent retention in both arches, so we were
unable to test for stability vs. relapse. Hopefully,
we can eventually accumulate cases with postretention
records. My prediction would be severe
relapse if the lower retainer is removed or lost.
I’d also like to study long-term records for
those Damon cases with long retention times,
searching for iatrogenic effects. I noted a few
Damon cases anecdotally over the years that had
labial and/or buccal gingival dehiscence of some
anterior and posterior teeth, a particular concern
that needs more study. We have not seen nearly as
many problems of this type in cases where there
was not arch enlargement.
DR. SINCLAIR Some say, “Little shows that all
orthodontic treatment fails.” So why bother trying
to achieve high-quality results?
DR. LITTLE Our work shows how cases postretention
are susceptible to the ravages of normal
physiology and aging. My message is that we
should strive for the highest-quality result for every
patient in order to achieve the best in health, function,
and esthetics. And once achieved, we need to
freeze the correction with lifetime retention. What
could be better than that?
One of our studies pointed out that the highest-
quality treated cases, as measured by ABO
standards, showed varying degrees of deterioration
once retainers were removed. To me, this does not
justify a lesser-quality result. Rather, it shows that
even the best treatment needs the crutch of fixed
retention to preserve the superior result. I advise
to aim high and maintain that correction. Our
patients expect and deserve our best efforts not just
for a few years, but for their lifetime.
In addition to our studies, I’ve gained much
from my orthodontic colleagues during casual
conversations at meetings and conferences on the
topic of stability and relapse. We need to be constant
students of this topic. I’d recommend that we
all maintain pretreatment and end-of-treatment
records of every patient and then strive to get every
JCO/NOVEMBER 2009
Dr. Robert M. Little
A B C
Fig. 2 A. 14-year-old patient with one missing incisor before treatment. B. After 23 months of active treatment,
with second incisor extracted. C. Good alignment 10 years after retention (age 30).
one of them back for their benefit and our continued
learning.
DR. SINCLAIR Now that you are “retired”, are
you still busy in professional orthodontics?
DR. LITTLE I continue to enjoy the occasional
orthodontic lecture trip. Particularly noteworthy
were invitations to New Zealand, Switzerland,
Germany, and Sweden, each an outstanding adventure
inside and outside the lecture hall. I’ve gained
much from interactions with colleagues while presenting
at about 130 lecture trips all over the world.
Combined with vacations to explore the local areas,
these trips have been truly wonderful.
I continue to enjoy developing teaching modules.
My friend and colleague Mike Fey and I did
a CD on cephalometric superimposition for ABO
applicants. This module has also been incorporated
into several graduate orthodontic programs.
I’ve also done a series of modules on cephalometrics
for Rebecca Poling’s outstanding educational
program, the International Training Institute.*
One recent offbeat teaching book plus CD
plus web format was quite a challenge, but fun. For
a local firm called American Tug that made my
own pleasure boat, I spent a year developing 12
chapters called “Tug Training and Tactics”. New
boat owners get a copy before their first voyage
from the dock. I must say that teaching has always
been and continues to be my hobby.
DR. SINCLAIR Thank you for sharing your
insights on the stability of orthodontic treatment
with our readers.
REFERENCES
1. Peck, S.
and Peck, H.: An index for assessing tooth shape
deviations as applied to the mandibular incisors, Am. J.
Orthod. 61:384-401, 1972.
*International Training Institute, 1000 O’Malley Road, Suite 104,
Anchorage, AK 99515; www.intltraining.com.
VOLUME XLIII NUMBER 11
martedì 2 novembre 2010
Editoriale n° 3/10 Ortodonzia Clinica e Interdisciplinare - Quintessenza Ediz.
Titolo: Schizofrenia
Oggi noi Ortodontisti conviviamo con una singolare dicotomia : da un lato la domanda di ortodonzia non è mai stata così alta, dall’altro la collaborazione che i pazienti sono disposti a fornirci non è mai stata così bassa!
Credo che a tutti noi capiti quotidianamente di affannarci sempre di più nel cercare “cure” che siano altamente efficaci ed efficienti, cercando di mantenere i nostri “consumatori” soddisfatti. E’ un bell’esercizio di equilibrio.
Anche perché dobbiamo, in ogni caso, fare i conti con la evidenza scientifica e con quanto sappiamo ( o dovremmo…) sapere.
Ackerman1-2 ci avverte correttamente sul fatto che la nostra sfida per il futuro sarà la necessità assoluta di integrare le prove scientifiche nella pratica clinica ortodontica.
Ismail e Bader 3 ci hanno raccomandato che dovremmo sempre unire insieme i bisogni di trattamento dei pazienti e le loro preferenze, con i migliori dati scientifici disponibili, infine con la competenza clinica dell’ortodontista.
Se vogliamo ancor più addentrarci nella “schizofrenia” di messaggi, richieste e affermazioni che coinvolgono i questi tempi la nostra professione potremmo fare nostre delle bellissime parole di un saggio di Jay Bowman4 : “ Patients often ask orthodontists, “Can you just fix this one tooth that is crooked?” Or they may pose the question, “Do you have to put braces on all of my teeth?” Would you not assume, despite these innocent inquiries, that they’d truly like all teeth to be properly aligned? But what is the “proper alignment” and can we all agree on a definition? By the way, what really are “straight” teeth and can we all agree on a definition? 5
How often have we been subjected to case reports with the end results justified with the inane and seemingly harmless statement, “But the patient was happy?” Is that enough? Is it sufficient justification for questionable treatment methods? If so, then why would we ever bother with removing teeth, dispensing headgear or elastics, driving tiny screws in bone, or “breaking jaws” to fit the teeth together? If patients are only focused on esthetics and not function,6 why bother? More importantly, why would we need an “orthodontic specialty” to deal with just lining-up the social six teeth? “
Non male, vero, come questioni da mettere sul tavolo?
Siamo veramente tutti d’accordo sulla definizione di “ denti dritti” ?
Perché preoccuparci tanto se il paziente infine guarda solo all’estetica?
Tutto comincia a traballare se cominciamo a percorrere queste strade…
L’unica possibilità che abbiamo per tenere fermo il pavimento è in fondo sempre la solita.
Non deviare da un metodo preciso e collaudato per formulare una corretta diagnosi, non cercare facili scappatoie già dalla primissima fase del trattamento, che è quella della accurata raccolta dei dati diagnostici.
Non a caso quindi “ The need to register clinical trials in orthodontics” è il bellissimo Editoriale con cui David Turpin apre il numero di Ottobre dell ‘ AJODO 7
L’ altra e definitiva “zeppa” per non fare più ballare il tavolo è il ricorrere sempre e con attenzione alla Evidenza scientifica.
Leggere, studiare, valutare, comparare sarà sempre il modo più serio e ragionevole di affrontare un percorso terapeutico.
Leggere, studiare, valutare, comparare sarà sempre la nostra polizza che ci assicurerà dal pericolo ( oggi così diffuso) di accumulare una notevole base di conoscenze senza imparare a distinguere correttamente tra scienza e pseudoscienza ".
References
1. Ackerman MB. Enhancement orthodontics: Theory and practice. Blackwell Munksgaard, Berlin, 2007.
2. Ackerman JL, Kean MR, Ackerman MB. Orthodontics in the age of enhancement. Aust Orthod J 2004; 20: 3A-5A.
3. Ismail AI, Bader JD. Evidence-based dentistry in clinical practice. J Am Dent Assoc 2004; 135: 78-83.
4. Bowman S. J. The social-six redux : is that really all there is ?Australian Orthodontic Journal, Volume 31(1), May, 2005.
5. Pinskaya YB, Hsieh T, Roberts WE, Hartsfield JK Jr. Comprehensive clinical evaluation as an outcome assessment for a graduate orthodontics program. Am J Orthod Dentofacial Orthop 2004; 126: 533-43.
7. Turpin D.L. The need to register clinical trials in Orhodontics A J Orthod Dentofacial Orthop 2006;130:429-430
Iscriviti a:
Post (Atom)