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Latest Dental World

January-February 2018

Giuseppangelo Fonzi

By Bernard Kurdvk - The use of porcelain in dental art dates back to the middle of the 18th century. An apothecary at Saint Germain-en-Laye by the name of Duchateau is the first to have been known to manufacture prostheses neither in bone nor in wood, but in imputrefiable materials. Then, Nicolas Dubois de Chémant, Parisian dentist and surgeon, modified the paste composition in porcelain and more useable results were obtained. A 15-year apprenticeship would follow before "dental fabrication and denture paste from incorruptible minerals without putrefaction" was made on September 16,1791. However these prostheses were manufactured from a single large piece, which, according to critics, hindered the denture's adjustment at the base of the mouth...


Giuseppangelo Fonzi: Industrial Fabrication Promoter of Porcelain Prosthetics

Fonzi-p79-f1
Fig. 1. Giuseppangelo Fonzi at age 40. (In Giuseppangelo Fonzi. Bartieri, Antonio Pavia, Rassegna Trimestriale di Odontiatria, 1958, 2:134-179)

The use of porcelain in dental art dates back to the middle of the 18th century. An apothecary at Saint Germain-en-Laye by the name of Duchateau is the first to have been known to manufacture prostheses neither in bone nor in wood, but in imputrefiable materials. Then, Nicolas Dubois de Chémant, Parisian dentist and surgeon, modified the paste composition in porcelain and more useable results were obtained. A 15-year apprenticeship would follow before "dental fabrication and denture paste from incorruptible minerals without putrefaction" was made on September 16,1791. However these prostheses were manufactured from a single large piece, which, according to critics, hindered the denture's adjustment at the base of the mouth.

Then came Giuseppangelo Fonzi, a few years later, who would advance the technique by making prostheses in porcelain.

When he arrived at Paris, Giuseppangelo Fonzi (Fig. 1) was already a well-travelled Italian, with abilities in many trades, and exerting various job metiers. Born July 13, 1768 at Spoltore, in the province of Teramo, Fonzi left his parents' home after accelerating secondary studies at Naples. He was to take part in the Spanish War. There he learned Spanish, astronomy, and navigation. Weary of maritime life, he set out for Spain and worked at various jobs to survive. This was how he became a travelling dentist, working in the open. At once passionate about the field, he decided to go to France to perfect and deepen his knowledge of dentistry. And so in 1795, Giuseppangelo Fonzi settled in Paris to practice his profession of dentistry He sought to expand the theoretical and technical aspects of his profession, and to improve the quality of his art by studying imputrefiable dentures.

He returned to Italy; then undertook a series of travels throughout Europe: Munich (1815), London (1816), Saint Petersburg (1823), Moscow (1825), Naples, then Paris (1826) with his nephew who was to learn the profession and would one day take over his work in the French capital, Madrid (1831), and finally Barcelona (1836) where he died in 1840. These trips enabled him to enrich his body of knowledge. His reputation as a specialist in the esthetic aspects of prosthetics was to be enhanced at each step of his travel (Bartieri, 1958 and Guerini, 1925). In fact, it was in Paris that his research in incorruptible dentures was carried out, achieving new ways and methods of practicing dentistry.

The gist of Fonzi's research lies in dissociating mineral teeth from their support during the prosthetic elaboration process. This represents a fundamental advance in the construction of prosthetic denture elements. Dubois de Chémant and those after him followed and copied his way of manufacturing dentures that entailed the construction of a large artificial bloc with respect to the form of the edentulous arch for each patient (Dubois de Chémant, 1788 and 1824). Such construction brought with it all the risks of failure due to the shrinkage inherent in the paste cushion.

In contrast, Fonzi's method eliminates this difficulty by preparing and manufacturing independently the teeth and their anatomic supports. This resolved, the ease and speed in regard to the manufacture of the denture are increased irrespective of the type of edentulous arch or the prosthesis.

To develop this technique, Fonzi developed a procedure that binds together the teeth and the denture base. His idea was to include a clamp (stud) in each tooth (Fig. 2, 3, and 4). The stud was first made of gold, but its low fusion temperature and very high malleability hindered it from forming a stable and rigid bond. Gold was then replaced by platinum. Being newly discovered, platinum's properties were not known until 1748. It is a metal that is strong, adhesive, ductile, and flexible, but, with the same dilatation co-efficient as that of glass. The bond with the ceramic teeth, is therefore, readily made and remains stable in the denture base. In 1807, Fonzi demonstrated his discovery to the Academy of Sciences. A commission comprised of Tenon, Gay-Lussac and Sabatier was formed and it presented its findings to a meeting on June 8,1807. The commission demonstrated Fonzi's procedure which touts (1) speed of manufacture, (2) esthetic appeals, and (3) ingenuity, all combined in one. The advantage of Fonzi's teeth lies in the fact that:

(1) The denture can be used for the complete set of teeth, incisor, canine, molar in both the upper and lower jaws.

(2) His denture has the color, corresponding to the natural teeth which they are meant to replace.

(3) The particular advantage of the Fonzi denture, before being baked and the platinum studs either per pendicular or horizontal, can be adjusted and incorporated and not hinder the required ease of movement.

Paradoxically, the commission's conclusion was very cautiously worded, even negative. In their eyes, Fonzi's invention was "a success too shaky and whose importance being too light to warrant approval." Such conclusions and observations did not discourage Fonzi. On February 4, 1808, he turned the Athénée des Arts (High School of Arts) where a commission was charged with examining his mineral teeth, the fabrication procedure, and the application of his prosthesis. The resulting report was presented on the 14th of March and published the 16th of May 1808 in the journal des Arts, des Sciences, de la Littérature et de la Politique. At the outset, Fonzi was congratulated for having brought together in his work not only the artistic talents, but also those of a biologist, physician, and chemist. It is this different approach that permitted him to arrive at the invention of terro-metallic teeth —while eliminating the inconvenience of other materials. A few supplementary modifications followed.

Fonzi-p80-81a-f2
Fig. 2. Placket of Fonzi's teeth. (Musée P. Fauchard, Paris).

In 1808 Fonzi made "elastic" clasps in the area of partial prosthetics, which did away with the encompassing bands around the residual teeth: the circumferential, or so-called "modern," clasp still in use today was thus developed. Further, he interspersed the crochets for esthetic appeal, a subject of current discussion!

The preparation procedure of the metallic bases is also described. The earlier process consists of affixing the porcelain teeth on the bases made of hippopotamus bone. This solution was, however, only a palliative, for the base would collapse from the effects of saliva and chewing.

Fonzi's teeth were reusable. In fact, this allowed Fonzi to bypass the porcelain base causing frequent errors and bleeding. Another type of base would be used. It was then the metal bases (gold then platinum). In order to make the bases, Fonzi took an initial wax impression of the mouth from which he made a plaster model of the edentulous jaw. After a clay impression of this model was made, Fonzi then cast it in bronze. On this bronze duplicate, he applied a plaque in gold (later in platinum) which produced an exact form of the edentulous arch.

 

Fonzi-p81b-f3w
Anterior teeth showing metallic retention studs. (Musee P. Fauchard, Paris).

Afterward, he only had to mount the teeth in relation to those missing, in the patient, and solder them to the metal base.

This method of bonding overwhelmingly satisfied the commissioners since "they could not in any way shake the [studded] teeth, regardless of the efforts made, even with the aid of a lever." By varying the position of the studs, Fonzi could utilize the same teeth for those at the tenon (horizontal stud) or for the adjoined prosthesis (perpendicular stud).

Not satisfied with having invented this technique, Fonzi worked on the paste composition. He achieved a composition of the following elements:

—Limoges or Kaolin argillaceous clay,
—Vanvres clay,
—Limoges silica,
—Titanium oxide,
—Zinc oxide,
—Uranium oxide,
—Magnesium oxide,
—Gold oxide,
—Platinum aluminum-chloride,
—Platinum filings,
—Gold filings.


By using these different metallic oxides (which are same as those utilized today) and adjusting their respective proportions, Fonzi was able to obtain 26 different tones, notably the transparent tint that allowed him to make the appearance similar to that of the natural tooth (the first time ever).

In fact, like the natural teeth, these mineral teeth were made in two parts:

—First, the internal, opaque part of the mineral teeth was made of Limoges or Kaolin argillaceous clay, which is the optic equivalent of the dentin;

—second, the transparent part deposited on the surface was made of Limoges silica, ensuring the prosthetic teeth their brightness and similarity to the studs.

The commission's conclusion was more favorable since they judged that this invention should be welcomed positively and that Fonzi deserved "the maxi mum recompense possible under the rules." Fonzi was thus awarded a gold medal and a crown. His artistic reputation was secure, and it spread with him wherever he traveled.

The article in the journal des Arts, des Sciences, de la Littérature et de la Politique concludes with a note explaining that given the abundance of reports from the Athénée des Arts (High School of Arts), the sequel to the reports on prosthetic teeth would be published in the following issue. It was not to be, however, and it was not until the issue dated June 14, 1808 that the editors published the terro metallic tooth article. The reason for the delay can be traced to the protest surrounding the awards and honors given to Fonzi.

Fonzi-fig4
Fig. 4. Boc of posterior teeth (Musee P. Fauchard, Paris).

We find this again involved Dubois-Foucou, a dentist enjoying a vast reputation at Paris, member of several scientific research groups, dentist to the King and the royal family, then surgeon-dentist of the Emperor and Empress. Initially, during the first tests bv Dubois de Chémant, he was opposed to the usage of porcelain in prosthesis; later Dubois-Foucou became a staunch supporter of this material. He went to war against this "foreign dentist, to whom one must teach French," a means for him to side against the terro-metallic teeth in favor of his own composition (Dubois-Foucou, 1808). Fonzi had two advantages over his jealous rival: first, his profound scientific knowledge, notably in chemistry, and second, his warm and creative spirit.

The most virulent of all adversaries was Ricci, a Parisian dentist. He contested feverishly the quality of Fonzi's procedure and the esthetic appeal of the latter's fabrication. Ricci tried all means to discredit Fonzi. He addressed a letter to the journal des Arts, des Sciences, de la Littérature et de la Politique in which he explained his intent to summon a jury to judge each of the two procedures. In response to Ricci's wish for a jury, Fonzi accepted the challenge on the condition that the jury consist of not only surgeon-dentists, but also surgeons, physicians, and chemists - a way to avoid any conflict of interest.

It took some time to form this jury, all being hesitant to enter into the polemics. Ricci was impatient; it took until the end of 1808 to get the jury together. The archives in the School of Medicine have records of the polemics which show the following events and their conclusion:

On December, 23 at the request of Ricci, the Interior Minister wrote to the Director of the School of Medicine, a certain Thoures, to name a professor to examine the question.

It did not take long for the School of Medicine to respond: on January 5, 1809, a preliminary report labelled "not sent" sowed the virulent reaction against the minister's intervention. In effect, since neither Ricci nor Fonzi brought up an issue of public safety, why did the Interior Minister intervene in the matter? The report also shows the School of Medicine giving a piece of mind in this matter vis-a-vis the dental prosthesis and the dentists involved. For physicians, the best prosthetic teeth were the natural human teeth taken from the patient or a corpse. In physicians' eyes, artificial teeth appear only as esthetic artifices capable at best of correcting the deformity due to a lost tooth or perhaps by facilitating speech. As far as mastication is concerned, they were impossible. In fact, for the physicians, prosthetic teeth were an imperfect and painful solution incurring enormous expenses.

On February 16, 1809, a new report insisted on the mode of tooth fabrication and the porcelain denture which was far from achieving- the satisfactory degree required. Despite the various modes of fabrication employed by different dentists, no one was able to imitate nature. That was why in the eyes of the physicians it was illusionary to remedy a lost tooth. Consequently, the polemic surrounding Ricci's challenge to Fonzi's procedure did not take place; the School of Medicine had yet to pronounce judgement on the matter. Finally on February 26,1809, in a response to the Interior Minister, it said that "the School of Medicine has no reason to take up the discussion." Following which, Fonzi published a work in 1809 titled Response to Mr. Dubois-Foucou, Surgeon-Dentist, on the Brochure He Published in 1808 under the title 'Expose on the New, Procedures for the Conception of the Said Teeth' and on the Letter Addressed to the Physicians. In this work, Fonzi developed his riposte; point by point he responded to Dubois-Foucou's attacks. First, Fonzi explained that his attacker's ability resided in the latter's capacity to extract the teeth rather than the manufacture of prostheses appropriate to the patients' needs, perpetuating thus the "Ancient" tradition. Then, from Dubois-Foucou's demonstration of his own composition Fonzi pointed out the ignorance of his rival, in particular the latter's weakness in chemistry. Fonzi went on to justify the necessity of separating the teeth from the base during the prosthesis preparation process. "If it is about," wrote Fonzi, "constructing a piece that has an equal superficies, it is undoubtedly easy to enlarge it by calculating the shrinkage so that it can, after being baked, coincide with the model. But, if it is a piece of irregular superficies, with many variations of small protrusions and intrusions, such as those found in an edentulous jaw, or one with solid stumps that is rather firm which are needed to make the pressure evener, or one which has teeth with the stumps and these protrusions and intrusions, how is it possible to calculate the shrink age, and be able to make it coincide with the jaw whose parts are irregular? This is an essential condition for otherwise the pressure would not be equal on all the superficies. It cannot be in just some points, and it must continue to work in spite of irritation, inflammation, pain, all of which would stop the most important function ordained by nature: mastication. Such a piece would not be any good, save for parade; it would have no use. I challenge Mr. Dubois-Foucou to make, following his procedures, a denture that would coincide with all the irregularities of a jaw."

In his conclusion, Fonzi did not hesitate to make the offer of providing to all dentists, including Dubois Foucou, his terro-metallic teeth so that they could avoid the recourse of using corpse teeth. In the end, he explained his reasoning, which contrary to that the other practitioners, purely philanthropic, seeking only to bring the benefits of his discovery to society.

"I will judge myself," Fonzi concluded, "to be more happy by simplifying the step of those coming after me and stopping, in their favor, all the ruses of the enemy, their jealousy, their rivalries in an art whose theoretical and practical uniformity will finally be fixated and permanent."

From Fonzi's conclusion we draw two conclusions:

First, is that Fonzi tried to respond to the criticisms made by the School of Medicine at Paris by separating himself from the financial aspect.

Second, and here is the major part, he sought to distribute his fabricated teeth "through a chain" of his colleagues. The idea of industrial fabrication of prosthetic teeth was developed. This idea did not take off until much later; tradition and scorn prevailed over technological novelty.

References

  1. Bartieri, Antonio. Giliseppangclo Fonzi. Pavia, Rassegna Trimestriale di Odontiatria, 1958, 2:134-179.
  2. Dubois de Chémant, Nicolas. Dissertation sur les avantages des dents incorruptibles de pâte minérale, suivie d'un jugement qui a condamné M. Dubois-Foucou et consorts, dans leur demande en nullite de brevet d'invention, qui avait été accord é a l'inventeur. Paris, I'auteur, 1824.
  3. Dubois de Chémant, Nicolas. Dissertation sur les advantages des nouvelles dents et râteliers artificiels incorruptibles et sans odeur, inventés par M. Dubois de Chémant, suivie d'une réfutation sommaire des assertions avancées par M. Dubois-Foucou dans la lettre aux auteurs du journal de Paris, le 18 mai 1788. Paris, I'auteur, 1788.
  4. Dubois-Foucou,Jean-Joseph. Expose de nouveaux procédés pour la conception des dents dites de composition. Paris, I'auteur, 1808.
  5. Fonzi, Giuseppangelo. Réponse a Monsieur Dubois-Foucou, chirurgien-dentiste, sur la brochure publiée par lui en 1808 sous le titre: Exposé de nouveaux procédés pour la conception de dents dites de composition et sur la lettre adressée a Monsieurs les dentistes. Paris, I'auteur, 1809.
  6. Guerini, Vincenzo. The Life and Works of Giuseppangelo Fonzi. Philadelphia and New York, Lea and Febiger, 1925.

Member of research group in ancient odontological texts and Frenciz research team in Dental Art History.
DR. KURDYK is an assistant at the Faculty of Dental Surgery, Paris V and at the Parisian Hospitals.
Correspondence: 2, rue de Monttessuy, 75007, Paris, France.

Article orginally published in the Journal of the History of Dentistry
Vol. 47, No. 2/July 1999 pp 79-82 copyright ©1999, all rights reserved

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