Questions & Answers

Questions & Answers

Disappearing enamel QUESTIONS & ANSWERS ness of cavity M oisture protection lining as a protective covering of the newly placed silicate is quest...

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Disappearing enamel


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.



petroleum jelly,


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

has set.


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

moisture.— Gerald

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

k J:'





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 .

(H um ­

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,

since the

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




described.— -

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


sufficiently— Richard

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

been studying

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




is based








principally on the


to allow



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

ing reduction

the locking action of the distal enamel



of the

have not as yet been corroborated by



second deciduous molar. is described



textbooks (for example, Graber, T. M. Orthodontics:

principles and


in recurrent caries oc-,

In other words, laboratory data>

in vivo tests. W e have tried this mechanism with zinc




so far,.

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






for example,



which might tie up the fluoride. W e have not found any composition, cluding the few




that are available that have fluoride added,





any In


our hands,

in the

mechanism is effective in silicate and has some


in certain


but it has not given the desired results in



cement.— R.


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

enchymal origin

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.

Periapical cyst

to place an antiseptic dressing in the cham ber?— W. R., d d s , San F ra n ­ cisco.


defects are



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

curet the

intensification and spread of the acute

involved area.

If histologic

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