Opinions On Tin Foil And Reasons For Using





At the World's Columbian Dental Congress, held in Chicago, August, 1893,

the author presented an essay on "Tin Foil for Filling Teeth."



During the discussion of the subject, the following opinions were

elicited:



Dr. E. T. Darby: "I have always said that tin was one of the best

filling-materials we have, and believe more teeth could be saved with it

than with gold. I have restored a whole crown with tin, in order to show

its cohesive properties; the essayist has paid a very high and worthy

tribute to tin."



Dr. R. R. Freeman: "I have used tin foil for twenty-five years, and know

that it has therapeutic properties, and is one of the best

filling-materials, not excepting gold."



Madam Tiburtius-Hirschfield: "I heartily indorse the use of tin, and

have tested its cohesive properties by building up crowns."



Dr. A. H. Brockway: "I am a strong believer in the use of tin, on

account of its adaptability, and the facility with which saving fillings

can be made with it."



Dr. Gordon White: "After having used tin for nine years, I claim that

it is the best filling-material that has been given to our profession."



Dr. C. S. Stockton: "Tin is one of the best materials for saving teeth,

and we should use it more than we do."



Dr. James Truman: "I use tin strictly upon the cohesive principle, and

would place it in all teeth except the anterior ones, but would not

hesitate to fill these when of a chalky character."



Dr. Corydon Palmer: "For fifty-four years I have been a firm advocate of

the use of tin, and I have a filling in one of my teeth which is forty

years old."



Dr. William Jarvie: "I rarely fill a cavity with gold for children under

twelve years of age that I want to keep permanently, but use tin, and in

five or ten years, more or less, it wears out. Still, it can easily be

renewed, or if all the tin is removed we find the dentin hard and firm.

The dentist is not always doing the best for his patients if he does not

practice in this way."



Dr. C. E. Francis: "I have proved positively that tin foil in good

condition is cohesive, and my views have been corroborated by dentists

and chemists."



Dr. James E. Garretson: "Tin foil is cohesive, and can be used the same

as gold foil, and to an extent answers the same purpose."



Dr. C. R. Butler: "Tin is cohesive and makes a first-class saving

filling."



Dr. W. C. Barrett: "Tin is as cohesive as gold, and if everything was

blotted out of existence with which teeth could be filled, except tin,

more teeth would be saved."



Dr. L. D. Shepard: "Tin possesses some antiseptic properties for the

preservation of teeth that gold does not."



Dr. W. D. Miller: "I use tin foil in cylinders, strips, and ropes, on

the non-cohesive plan, but admit that it possesses a slight degree of

cohesiveness, and when necessary can be built up like cohesive gold by

using deeply serrated pluggers."



Dr. Benjamin Lord says, "It is said that we know the world, or learn the

world, by comparison. If we compare tin foil with gold foil, we find

that the tin, being softer, works more kindly, and can be more readily

and with more certainty adapted to the walls, the inequalities, and the

corners of the cavities.



"We find also that tin welds--mechanically, of course--more surely than

soft gold, owing to its greater softness; the folds can be interlaced or

forced into each other, and united with more certainty, and with so

much security that, after the packing and condensing are finished, the

mass may be cut like molten metal.



"I contend moreover that for contouring the filling or restoring the

natural shape of the teeth, where there are three walls remaining to the

cavity, tin is fully equal to gold, and in some respects even superior;

as tin can be secured, where there is very little to hold or retain the

filling, better than gold, owing to the ease and greater certainty of

its adaptation to the retaining points or edges of the cavity.



"It will be said, however, that tin fillings will wear away. The

surfaces that are exposed to mastication undoubtedly will wear in time;

but the filling does not become leaky if it has been properly packed and

condensed, nor will the margins of the cavity be attacked by further

decay on that account.



"Altogether, I believe that we can make more perfect fillings with tin

than we can with gold, taking all classes of cavities; but it must not

be understood that it is proposed that tin should ever take the place of

gold where the circumstances and conditions indicate that the latter

should be used. Of course, the virtue is not in the gold or the tin, but

in the mechanical perfection of the operation, and tin having more

plasticity than gold, that perfection can be secured with more ease and

certainty.



"If we compare tin with amalgam, we must certainly decide in favor of

the former and give it preference; as if it is packed and condensed as

perfectly as may be, we know just what such fillings will do every time.

We know that there will be no changes or leakage of the fillings at the

margins; whereas, with amalgam, the rule is shrinkage of the mass, and

consequently the admission of moisture around the filling, the result

being further decay. It is not contended that this is always the result

with amalgam, but it is the general rule; yet we must use amalgam, as

there are not a few cases where it is the best that we can do; but it is

to be hoped, and I think it may be said, that as manipulative skill

advances, amalgam will be less and less used. For so-called temporary

work, very often I prefer tin to gutta-percha, as it makes a much more

reliable edge and lasts longer, even when placed and packed without

great care."--N. Y. Odon. Society Proceedings, page 51, 1894.



One of the main reasons which induced the writer to begin the use of tin

foil (Stannum Foliatum) for filling teeth, in 1867, was the fact that

amalgam filling failures were being presented daily. Believing that tin

could do no worse, but probably would do better, we banished amalgam

from the office for the succeeding seven years, using in the place of

it tin, oxychlorid, and gutta-percha. Since that time we have seen no

good reason for abandoning the use of tin, as time has proved it worthy

of great confidence. There is no better dental litmus to distinguish the

conservative from the progressive dentist.



If we take a retrospective view and consider what tin foil was thirty

years ago, we do not wonder that so many operators failed to make tight,

good-wearing fillings. As it came from the manufacturer it looked fairly

bright, but after being exposed to the air for a short time it assumed a

light brassy color, and lost what small amount of integrity it

originally possessed. This tin was not properly refined before beating,

or something was put on the foil while beating, so that it did not have

the clean, bright surface and cohesive quality which our best foil now

has. No. 4 was commonly used, but it would cut and crumble in the most

provoking manner. Fillings were made by using mats, cylinders, tapes,

and ropes, with hand-pressure, on the plan for manipulating non-cohesive

gold foil, but it was difficult to insert a respectable approximal

filling.



From the best information obtainable, the writer believes that Marcus

Bull (the predecessor of Abbey) was the first to manufacture and sell

tin foil in the United States, as he began the manufacture of gold foil

at Hartford in 1812.



Several years ago a radical change came about in the preparation of tin

foil, for which the manufacturer should have his share of the credit,

even if the dentist did ask for something better, for the quality

depends largely upon the kind and condition of the tin used and on the

method of manufacture.



For making tin foil for filling teeth, the purest Banca tin that can be

obtained is used. The tin is melted in a crucible under a cover of

powdered charcoal. It is then cast into a bar and rolled to the desired

thickness, so that if No. 6 foil is to be made, a piece one and one-half

(1-1/2) inches square would weigh nine grains. This ribbon is then cut

into lengths of about four feet, and spread on a smooth board slanted,

so that the end rests in a vat of clean water.



Then apply to the exposed surface of the ribbon diluted muriatic acid,

and immediately wash with a strong solution of ammonia. Turn the ribbon

and treat the other side in the same way. It is then washed and rubbed

dry. The object of using the acid is to remove stains and whiten the

tin, and the ammonia is used to neutralize the effect of the acid.



The strips are then cut into pieces one and a half inch square, filled

into a cutch and beaten to about three inches square. It is then removed

from the cutch and filled into a mold, and further beaten to the desired

size. When the ragged edges are trimmed off, the foil is ready for

booking.



It takes skill and experience to beat tin foil, for it is not nearly as

malleable as gold; up to No. 20 it is usually beaten, but higher numbers

are prepared by rolling. In each case the process is similar to that

employed in preparing gold foil. The number on the book is supposed to

indicate the weight or thickness of the leaf. On the lower numbers the

paper of the book leaves its impression.



On weighing sheets of tin foil from different manufacturers a remarkable

discrepancy was found between the number on the book and the number of

grains in a sheet, viz: Nos. 3, 4, 5, weighed 7 gr. each; No. 6, 9 gr.;

No. 8, from 9 to 18 gr.; No. 10, from 14 to 15 gr.; No. 20, 18 gr. In

some instances the sheets in the same book varied three grains. We

submit that it would be largely to the advantage of both manufacturer

and dentist to have the number and the grains correspond. No dentist

wishes to purchase No. 8 and find that he has No. 18; no one could sell

gold foil under like circumstances. Of the different makes tested,

White's came the nearest to being correct. The extra tough foil which

can now be obtained is chemically pure, and with it we can begin at the

base of any cavity, and with mallet or hand force produce a filling

which will be one compact mass, so that it can be cut and filed; yet in

finishing, it will not bear so severe treatment as cohesive gold. Always

handle tin foil with clean pliers, never with the fingers; and prepare

only what is needed for each case, keeping the remainder in the book

placed in the envelope in which it is sold, otherwise extraneous matter

collects upon it, and it will oxidize slightly when exposed to the air

for a great length of time.



Before using tin foil, a few prefer to thoroughly crumple it in the

hands or napkin, under the impression that they thus make it more

pliable and easier to manipulate.



A piece of blue litmus paper moistened and moved over a sheet of tin

foil will occasionally give an acid reaction, probably owing to the acid

with which it is cleaned before beating not having been thoroughly

removed. Foil held under the surface of distilled water and boiled for

five minutes, then left until the water is cold, removed and dried,

shows it has been annealed, which makes it work easily, but not as hard

a filling can be made from it as before boiling.



In selecting and using this material for filling, we are able fully to

protect the cavity; and if we understand the material, and how to

manipulate it, we will surely succeed. This statement demands serious

attention, and appeals to every one who is anxious to practice for the

best interests of his patients; then let us make a thorough study of the

merits of the method and material.



Until recently, the term cohesion had but one special meaning to

dentists, and that as applied to gold for filling teeth; being

understood as the property by which layers of this metal could be united

without force so as to be inseparable. The writer claims that good tin

foil in proper condition is cohesive when force is applied, and can be

used for filling teeth in the same manner in which cohesive gold foil is

used. This claim has been confirmed by several dentists, as noted in

another part of this volume.



Cohesion is the power to resist separation, and it acts at insensible

distances. The integral particles of a body are held together by

cohesion, the constituent parts are united by affinity.



The attraction between atoms of pure tin represents cohesion. Marble is

composed of lime and carbonic acid, which are united and held together

by affinity.



The condition which obtains in the tin may be called cohesion, adhesion,

welding, or interdigitation, but the fact remains that layers of tin

foil can be driven together into a solid mass, making a tight filling

with less malleting than is required for gold; if it is overmalleted,

the receiving surface is injured.



On account of its pliability it is easily adapted to the walls and

margins, and a perfect fit is made, thus preventing capillary action and

preventing further caries. Of all the metals used for filling it is the

best tooth-preserver and the most compatible with tooth-substance, and

the facility with which a saving filling can be made largely commends

it.



Tin has great possibilities, and has already gained a high position as a

filling-material. Upon the knowledge we possess of the possibilities and

limitations of tin as a filling-material, and our ability to apply that

knowledge, will largely depend our success in preserving teeth.



It is a good material for filling many cavities in the temporary teeth,

and children will bear having it used, because it can be placed quickly,

and but little force is required to condense one or two layers of No. 10

foil. The dentin in young teeth has a large proportion of organic

material, for which reason, if caries takes place, many believe it is

hastened by thermal changes. Gold fillings in such teeth might prevent

complete calcification, on account of the gold being so good a

conductor; but if tin is used, there is much more probability of

calcification taking place, because of its low conductivity and its

therapeutic influence. It does not change its shape after being packed

into a cavity. Under tin, teeth are calcified and saved by the deposit

of lime-salts from the contents of the dentinal tubuli. This is termed

progressive calcification.



Like other organs of the human body, the teeth are more or less subject

to constitutional change. The condition in which we find tooth-structure

which needs repairing or restoring should be a sure indicator to us in

choosing a filling-material. Up to the age of fourteen, and sometimes

later, we find many teeth which are quite chalky. In some mouths also,

at this period, the fluids are in such a condition that oxychlorid and

oxyphosphate do not last long; for some reason amalgam soon fails, while

gutta-percha is quickly worn out on an occlusal surface. In all such

cases we recommend tin, even in the anterior teeth, for as the patient

advances in years the tooth-structure usually becomes more dense, so

that, if desirable, the fillings can be removed, and good saving

operations can be made with gold. By treating cases in this manner very

little, if any, tooth-structure is lost.



The teeth of the inhabitants of Mexico and Guatemala are characteristic

of their nervous and nervo-lymphatic temperaments; children ten years of

age often have twenty-eight permanent teeth, and they are generally soft

or chalky, but our dentists there report good success in saving them

with tin.



In filling this class of teeth, we should be very careful not to use

force enough to injure the cavity-margin, for if this occurs, a leaky

filling will probably be the result. Still, we have seen some cases

where slight imperfections at the margin, which occurred at the time

of the filling or afterward, did no harm, because the deposit of tin

oxid filled up the ends of the tubuli, thus preventing caries. We

believe that this bar to the progress of caries is set up more

frequently when tin is used than with any other metal under like

conditions.





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