QUESTIONS & ANSWERS
ness of cavity
M oisture protection
lining as a protective
covering of the newly placed silicate is questionable.
Q. Since Squibb’s Orabase has con siderable adhesive properties, would it be superior to cocoa butter for protecting newly placed silicates from moisture. I know cavity lining is used to protect silicates. Is this as good or better than cocoa butter? Also, it is not routine to cover ce ment as in crown and bridge work witb a moisture barrier. Why not? Would it be helpful?— t h o m a s p . f r e e m a n , d d s , Lieutenant Colonel, DC, U.S. Army, San Francisco.
silicone grease all have been used to maintain water balance of the silicate during
rather prolonged chemical
reaction. The basis for selection of one of the materials would seem to be (1 ) its availability and ease of application, (2 )
its water repellency, and (3 ) the
its activity. The
grease (Dow Corning, Stop Cock Grease — Silicone Lubricant) excels at least in the last two areas. Someday, perhaps some specific silicone grease might be more readily available to the profession in a slightly altered form. Cementation
procedures for inlays,
Squibb's Orábase derives its clin
crowns and bridges must be done in
ical adhesive characteristics by contact
a dry field. Premature moisture contact,
with moisture. To be adhesive to the
before set, will destroy the properties
newly inserted silicate, the restoration
of the cement.
and surrounding tooth tissue would re
zinc phosphate cement will vary be
setting time of
quire wetting. Thus, the intended pur
tween 4 and 10 minutes (according to
pose of protection from moisture would
the A D A Specification no. 8 ).
be negated. Orabase actually picks up
tion from the oral fluids would need to
water from the oral environment and
be maintained only until the cement
should not be considered a moisture re
the burnishing action on the casting
C avity lining or varnish is composed
Immediately on cementation,
margins should, theoretically, exclude
Q. Can you explain why the enamel on teeth, especially the posterior teeth, should disappear through the years? I have two adults in my practice whose dental needs I have been at tending to for the past 10 to 15 years. One is a woman, 72, and the other, a man, aged 33. They are not related. I first noticed the condition occur ring in the woman about 8 or 9 years ago. With each recall, I could see the enamel on her posterior teeth was slowly being lost. I could see my alloy fillings were slowly appearing “high” on the tooth’s surface. The fillings were inserted flush with the tooth surfaces and definitely are not expanded or “lifting.” The enamel on the lingual surfaces of the upper cuspids also is “washing” aw£y. Re maining tooth surfaces are clean and smooth. In discussing the problem with the patient and questioning her diet and medications, I learned she was re quired (and still is) to take mild hy drochloric acid medication (liquid, orally) since her stomach does not produce it sufficiently. She neither uses lemons or other citrus to excess, nor does she regurgitate her food. The man’s loss of enamel is rela tively recent! I noticed this happen ing about 2 years ago. He takes no medication, eats no excess citrus, and has no regurgitation. His posterior restorations are now higher than the tooth surfaces. Both patients have many alloy re storations, and both wear removable prosthetic appliances—all cast chrome alloy (Nobilium). Is it possible that a chemical reaction between the chrome alloy and the amalgam restorations, resulting in the formation of an acid ic salivary medium, is causing the erosion?— a l b e r t j . s a s s o , d d s , Waterbury, Conn.
of gums or resins in an organic solvent.
cement from possible contact with oral
On evaporation of the solvent, a fine
fluids. The time involved and nature
film of the resinous material remains
of the procedures seem to indicate little
that acts as a semipermeable mem
need for this type of protection from
brane, permitting, to some extent, the
acid medication, no doubt, was a strong
penetration of moisture. The effective
Ann Arbor, Mich.
contributing factor to the decalcifica-
tion of the teeth. The medication was
exposed most readily to the tooth sur
1962, p. 3 2 4 ).
faces that demonstrated enamel loss. In
cause exists, one might find that fre
If this ligature method is impractical, a band and repositioning wire technic could be considered. This method has
quent exposure to many of the soft
been described by Humphrey
drinks could result in a décalcification
phrey, W .
P. Simple technic for cor
similar to that produced by hot lemon
recting an ectopic erupting first per
ade, citrus sucking, and frequent re
manent molar. J . Den. Children 29:176
gurgitations. The pH of 2.5 to 3.0 of
3rd quart., 1962).
many of these drinks helps them com
As a lost resort, the second decidu
pete with the well-known acid drinks
ous molar could be removed and the
first permanent molar repositioned dis
stom ia), the effects of these low pH fluids
is more pronounced,
clearance capacity and buffering po tential is reduced or absent. Reactions amalgam
Their use together, in the mouth, has been common for many years without resulting
Robert B. W olcott, DDS, Los Angeles.
D elayed eruption Q. Radiographs of a 6 Vi-year-old girl show the halted eruption of the upper right first perm anent m olar. It is locked behind the upper right second deciduous m olar. A pparently,
(with a removable appliance)
rect position, a space maintainer would
m olar. This treatm ent has the pos sible disadvantage of causing the first perm anent m olar to erupt mesial to its correct position. 3. Rem ove the distal third o f the second deciduous m olar, and provide a restoration that will protect the exposed pulp but still allow enough room for the first perm anent m olar to erupt. This m ethod might hasten the pulpal death and prem ature ex foliation of the deciduous tooth. It should be added that this p a tient will probably have to undergo orthodontic treatm ent fo r the cor rection of an anterior cross-bite, probably due to the traum atic loss of the 2 deciduous m axillary cen tral incisors w hen she was about a year old.— t h o m a s p . f r e e m a n ' DDS, and MARSHALL M . SWAIN, DDS, San Francisco.
be necessary until the second bicuspid had
F luoridated cem ent Q. A card that a local orthodontist gives to his patients includes the fol lowing statem ent: “The areas under these bands are protected by fluori dated cem ent and are relatively safe while the band is cem ented on the tooth.” Such a fluoridated cem ent sounds as though it would be an ex cellent m aterial to place beneath fill ings and inlays. C an you tell me w here I can buy some?— h o r t o n d . k i m b a l l , d d s , Detroit.
A t the Indiana University School
of Dentistry, we have A . Notwithstanding the fact that major orthodontic therapy may be needed in the future and that often an impacted first permanent molar portends a future
804 ■ JA D A , Vol. 72, April 1966
fluoride uptake by enamel and dentin from
phenomenon that occurs with silicate cement. Probably, the excellent resist
lack of sufficient space for the perma
nent teeth, treated
Jennings, DDS, Houston, Texas.
the distal root of this deciduous m olar has been resorbed, perhaps even to the coronal portion of the pulp. Clinically, neither tooth is displaced either to the labial or lingual side. W hat treatm ent, if any, do you suggest for this girl? W e see three possibilities: 1. T reat at this tim e. This course has the possible disadvantage of causing the first perm anent m olar to lose its “eruptive pow er” during the 4-year interim that the second de ciduous m olar m ay remain. 2. E xtract the second deciduous
it erupts. Once this tooth is in its cor
principally on the
appreciable fluoride uptake by the ad joining enamel and the corresponding
proceed as normally as possible, preferred treatment would be
reduction in enamel solubility. Selected
to pass a piece of 0.020-inch brass
fluorides can be added to certain resin
systems, and a corresponding fluoride
area, twist the ends to form a loop, and
uptake occurs; however, as yet there is
allow this device to wedge the first per
no clinical evidence that a correspond
manent molar distally and free it from
the locking action of the distal enamel
have not as yet been corroborated by
second deciduous molar. is described
textbooks (for example, Graber, T. M. Orthodontics:
in recurrent caries oc-,
In other words, laboratory data>
in vivo tests. W e have tried this mechanism with zinc
have never been able to add fluoride to this type of cement and get any.m eas urable fluoride uptake. W e have tried numerous
which might tie up the fluoride. W e have not found any composition, cluding the few
that are available that have fluoride added,
mechanism is effective in silicate and has some
but it has not given the desired results in
A . Let me first list the abnormalities present and from this make some a t tempt at diagnosis: 1.
The lateral incisor is nonvital.
2. There is displacement of the in volved tooth. 3. There is incomplete development of the lateral incisor root. apex. 4. There
is suppuration through a
5. The area of radiolucency appar ently involves only the lateral incisor with the greatest destruction of bone above the apex. The
A boy, age 13, in good health except fo r occasional attacks of asthm a, cam e for his first visit to the dentist. R adiographs show a large radiolucent area above the right lateral incisor. N o tum efaction can be felt on the labial or palatal side.
fairly well circumscribed.
from an invasion of the apical perio dontium by pathogenic microorganisms this interpretation is correct, the sooner that drainage is established, the faster and more favorable will be the ultimate resolution of the infective process. In abscess has spread and localized, an
These facts lead me to conclude that.
opening should be made into the pulp
this is a large periapical cyst that has
chamber to establish drainage, if pos
been slow in developing. It is probably
sible via the root canal. This technic is
the result of trauma that occurred many
helpful in relieving periapical pressure,
years earlier, since root end develop ment of the lateral incisor is incomplete.
providing an avenue of escape for the inflammatory exudate. In many in
A n osteolytic tumor is unlikely but
stances, especially when instituted early,
not impossible. Ameloblastoma is rare
this procedure alone gives the patient
in the anterior region and is seldom
relief and prevents further involvement
unilocular. Odontogenic tumors of mes
of periapical tissues and surrounding
bone. The pulp chamber should be loosely
(in other words, fi
broma or myxoma)
usually occur in
packed with cotton to prevent blockage
young adults and may have nothing
of the opening by the packing of food
characteristic to distinguish them from
and the tooth left unsealed. Drainage
cysts. The central giant cell tumor of bone may displace teeth and resemble
can be encouraged by having the pa tient rinse often during the next few
a cyst but there are usually an asso
days with warm water or saline solu
ciated loss of lamina dura, root resorp
tion. The patient should also be in
tion, and multiple areas of involvement,
structed to draw (suck) on the tooth during rinsing to further encourage
and the large.
T h e lateral incisor appears to be in the process of displacem ent; it is being pushed away from the cuspid and behind the central incisor. Aside from vitality test results being nega tive, the only objective sym ptom s are redness and an apparently suppurat ing pocket on the labial side. The boy, who seems to be highly intel ligent, does not rem em ber any traum a. Is this just an extra large periapical granulom a and, if so, w hat m ight be the cause? Is there any evidence apparent in the radio graph of a possible osteolytic tum or? W hat are your suggestions for treat m ent?— h u g o D o m i n g u e z , d d s , Mis sion, Texas.
I presume that this inquiry refers
to an acute apical abscess, which results
the early phases, preferably before the
residing in an infected necrotic pulp. If
pocket on the labial side.
Phillips, DSc, Indianapolis.
to place an antiseptic dressing in the cham ber?— W. R., d d s , San F ra n cisco.
Since the area of destruction around
No attempt should be made to seal
the lateral incisor is so extensive and
the tooth with an antiseptic dressing as
since some form of osteolytic tumor is
long as the symptoms of acute infection
possible, my treatment of choice would
remain. Sealing of the tooth in such
be to remove the lateral incisor and
instances blocks drainage and results in
intensification and spread of the acute
examination disclosed tissue other than
inflammatory process. A fter the acute
cystic, subsequent wider excision, if in
symptoms have subsided, and the tooth
is neither painful nor excessively mobile
could be performed.— Myron
Kaufman, DDS, Detroit.
and tender, an antiseptic dressing may be sealed in the pulp chamber and root canal treatment commenced. If endo dontic treatment is not contemplated,
Pulp cham ber drainage
the tooth may be extracted at this time without incurring undue risk of unfa vorable postoperative sequelae.— Charles
Q. W hen treating an acute infection (with swelling) of the pulp on the first visit, after effecting some type o f drainage, how can one decide w hether to leave the pulp cham ber open until the next visit or w hether
Maurice, DDS, M S, Chicago.
Q U EST IO N S & A N S W E R S ■ 805