Fig. 1.1 • Maya mandible discovered by Wilson Popenoe (1938).
And nothing more would have been known of it had it not been for Italian, Amedeo Bobbio (born in Genoa but living in Brazil where he lectured in implantology at the University of Santos), who “rediscovered” it, and provided scientific evidence that the three pieces of shell had actually been inserted before death and thus constituted the most ancient evidence of alloplastic implants performed in man. Here is Bobbio’s description:
“In the course of my research, conducted in all the sections of the museum, I suddenly came across something as important as it was unexpected: a large and compact piece of jawbone, almost the whole mandibular body, more damaged on the right, where it lacks the supporting processes. This is the sequence of the teeth present: lateral incisors and canines on the right; canine, premolars, first and second molars on the left.
But the extraordinary thing is that the three missing incisors have been replaced by the same number of artificial teeth, which have been crafted from shell valves and implanted.
The imitation of natural teeth is truly extraordinary, in spite of their being flattened antero-posteriorly.
Overall, the shape, including the endosseous radicular part, is reminiscent of an elongated wedge-shaped triangle.” (…) “The natural teeth present in the segment show no sign of caries, although the natural teeth in the left hemi-arch have small fracture lines in the enamel; these are mainly horizontal and located on the vestibular side, although there also vertical ones on the canine.
In the implanted “teeth”, especially the one on the left, a short transverse groove has carefully been made under the incisal margin.
The left central incisor is implanted in an abnormal position, being rotated on itself through an angle of around 80° in such a way that its anterior side, which has the larger horizontal diameter, is sideways on, perpendicular to the other teeth. This, at least, is how it clearly appears in my photograph; instead, in the picture belonging to the museum, taken in 1935, which is slightly out of focus, this anomaly is much less evident. It is probable that the tooth fell out at some point and was reattached by force in this clearly incorrect position. There is no or little literature on this mandible and until now, little or nothing was known of it.
However, once again going through the correspondence of the Peabody Museum, I have been able to find some information in a letter dated 2nd May 1956 and written by the then director J.O. Brew to the British implantologist Boris Trainin, who had requested details of a ‘cranium with implanted teeth.’ In his letter, Brew replied that, according to the members of the expedition itself, the mandible which had three implanted incisors dated back to the eighth century a.C.; he specified that the teeth were implanted ‘post-mortem’, perhaps as part of a funeral rite. (…) My opinion is quite different. I was fortunate enough to be able to take, on 25th June 1970, at Harvard Medical School, the very first radiograph of all the teeth in the mandible. From this, we were able to document, beyond doubt the presence of osteogenesis, even compact osteogenesis around the extremely firmly implanted teeth, which were quite probably inserted using a method very similar to the ones currently used by Linkow and Muratori. From the radiographic image of the natural teeth, which shows that the apices are still incomplete, and from the relatively small size of the mandibular body, the fragment seems to be from a female of around 20 years of age.
In conclusion, we had before us the earliest authentic endosseous alloplastic implants yet discovered, which were applied in a living subject and were without doubt functional for some years.”
It would be interesting to know the surgical technique that was used to insert these three implants that, coming to light after so many years, were held in situ by the compact bone that had formed around them, found to be “radiographically similar to that which would surround an osseous implant today”. What is certain is that they were fixed into bleeding sockets, given that Bobbio provided radiographic evidence of the bone reaction that secured them in the living subject. Furthermore, the implants would have to have been prepared in a short space of time (if there did not exist ready-made inserts), because otherwise the sockets would have healed. Anaesthesia should not have been a problem, given that the peoples of Central America were certainly familiar with the hallucinogenic and anaesthetic properties of coca leaves and of certain mushrooms; the sockets would have been prepared using manual bow drills, probably using the same “burs” they used to make aesthetic engravings on the anterior surfaces of front teeth.
The answer to the question of how these first – and, for now, only – alloplastic implants were secured during the process of reparative osteogenesis probably lies in the presence of the horizontal grooves, which probably served to hold some sort of temporary binding.
It is clearly highly likely that masticatory force was applied immediately after the placement of the shell “teeth”.
Leaving aside the various attempts at dental implantation and reimplantation made over the centuries by different authors, it is worth recalling what was done by Pierre Fauchard (1678-1761), who is considered the founder of modern odontostomatology. In his seminal work “Le Chirurgien Dentiste, ou traitè des dents” he described five cases of reimplantation and one of transplantation, all followed by immediate loading.
Particularly interesting is the following description. Fauchard claimed that “a colleague from the provinces whose name he could not remember” had suggested to him a particular transplant technique that consisted of making a few notches in the root of the extracted tooth as this would allow it, once transplanted, to become consolidated in the new socket “which, surrounding the root on all sides, would be able to feed its excrescences into the grooves”; thus “encased it would last for a considerable time”. According to the author, the patient was able to masticate very soon after this procedure.
These transplants, from “donor” to “recipient” were very widespread in Paris in the century in which Fauchard lived, a period that saw “rich patients buying teeth from the poor”. In this regard, it is worth reading another description provided by Fauchard:
“On 10th April, 1725, I received the daughter of Mr Tribuot, supplier to the King. She was greatly distressed by a violent pain caused by a caries of the first small upper molar on the right. The girl wanted the tooth extracted to rid herself of the pain, but was undecided, fearing that she would be disfigured. She therefore wondered whether it might not be possible for me to reimplant the tooth, as I had already done for her younger sister. I replied that this could easily be done, providing the tooth did not break during the extraction, the socket was not splintered and there were no lacerations of the gums. In the end she decided to go ahead.
I extracted the tooth with great care. It was not damaged, and neither were the socket or gums; therefore, I was able to replace the carious tooth in its socket and secure it, using ordinary thread, to the adjacent teeth. I left it thus bound for several days, until it had definitively stabilised (…) To conserve the tooth better I filled the carious cavity with lead.”
Driven by the scientific innovation begun by Fauchard, others in Europe began dealing with these same problems.
Louis Fleury Lecluse (1754), who invented and gave his name to the still extremely useful elevator for lower third molar dislocation, reported carrying out, with excellent results, around three hundred reimplantations, often of pulpitic teeth. He would remove and restore these teeth, filling them with lead, and then replace them. He maintained that normal function was regained only after an interval eight days.
In the nineteenth century in the United States, implants, including immediately loaded ones, were attempted and experimented by the forerunners of scientific dentistry.
It was around the 1840s when Harris and Hayden, founders of the Baltimore dental school, attempted endosseous implantations using artificial teeth that they had made from iron.
Harris, in particular, was the first to place, in an artificial socket, a platinum post that had been coated with cast iron “so that it resembled the root of a natural tooth”. Harris had then roughened the iron to increase its ability to retain the “new” tissue that was expected to form in the artificial socket. Once he had removed the binding that had been used to secure it temporarily to the adjacent teeth, the implant was covered with a porcelain crown which, according to Harris, was successful.
Nowadays, we know that iron is not biocompatible. Therefore, around Harris’s implant there must have formed hypertrophic, reactive and inflammatory tissue, capable of creating, temporarily, the impression of stability.
Three similar procedures (implants inserted in surgically prepared sockets) were performed by Perry and by Edward (1888 and 1889), and were, likewise, reported to be successful.
Slightly different implants, although still lead-coated, were used by Edmunds in New York. He reported that, on 21st October, 1886, he had inserted a platinum “capsule”, which had been coated in lead and then roughened using a drill.
Four years later, on 12th March, 1889, he carried out a similar procedure during the annual congress of the First District Dental Society of New York. It is interesting to recall that the same year he had used another of these implants in a colleague, Juan Josef Ross of Guatemala, implanting it an artificial socket in the area of an upper incisor that had been lost some time previously. He reported that four years afterwards, Dr V.H. Jackson, who had been present at the original operation, was able to confirm that the artificial tooth “was still in place and remarkably firm, without the surrounding tissue showing any sign of irritation”.
In the same year that Edmunds used his first lead-coated platinum “capsule” (1896), Lewis implanted a porcelain tooth with a gold support, which he, too, reported to be successful!
Two years later, Znamensky, a German, described some of the experiments that he had conducted with endosseous implants made of “engraved porcelain”, rubber, and gutta percha.
In March 1895, Bonwill, before the First District Dental Society of New York, described his successful implantation, in artificial sockets, of perforated tubes and solid posts in gold or iridium, used “both to replace single teeth and to restore entire dental arches”.
It was, however, the early 20th century that saw the laying of the foundations for the future development of scientific implantology.
Greenfield, between 1905 and 1913, invented and refined his “latticed cage” design, i.e. basket-shaped structures designed to be inserted into artificial sockets where they would trap, internally, a portion of bone tissue; despite their defects, these structures heralded one of the developments subsequently seen in the field of modern implant prosthetics.
Casto and Kauffer, in 1914 and 1915, respectively, used “spiral-shaped” implants in iridioplatinum, declaring themselves satisfied with the results obtained.
In the wake of the First World War, Frenchman Leger-Dorez (1920) created an “extendable root” implant; being based on the concept of forced tightening of the implant in the bone, it was much like today’s expansion bolts. Leger-Dorez considered the mechanical compression induced in this way an important innovation; he believed that his implants would immediately be stable, thus eliminating the need to wait for them to be incorporated “biologically” by the process of reparative osteogenesis.
Leger-Dorez’s four-piece “tubular extension” implant was made from 24 K gold (the “body) and platinum (the internal expansion screw).
In the same year, Weigele placed truncated cones, in ivory, in artificially prepared sockets; the cones were then protected by suturing the mucosa over them; the idea was that the ivory would stimulate a gradual process of resorption by osteoankylosis, sufficient to allow temporary loading of a subsequently inserted implanted tooth. Years later, Weigele reported that he had used his ivory cones in the temporary anchoring of complete lower dentures, as they provided endosseous support for the superstructures used.
In 1939 the Strock brothers in Boston started to test, in humans, their vitallium screw implants – vitallium is a cobalt, chrome and molybdenum alloy –, which they had previously tested in dogs. Despite being another milestone in the progress of implant prosthetics, the scientific reports they produced on this topic, modest, cautious and elegant, remained little known and were associated with the failures of other methods.
In 1941, Irwing proposed another rapid-expansion post-extraction implant that, like the earlier one devised by Leger-Dorez, had little success.
In 1946 Goldberg and Gerschoff proposed juxta-osseous implants in vitallium; these rested on the mandibular crest and were held in place by screws; they were mainly indicated for use in the lower jaw.
1947 was a historical year as it saw the birth of the modern concept of implantology: on February 27th of that year, during a conference held at A.M.D.I. (the Italian Dentists’ Association) in Milan, Italian Manlio Formiggini proposed his spiral implant with hollow core made from stainless steel wire or tantalum, a silvery-white coloured material. This technique, referred to by its inventor as direct “intramaxillary infibulations”, marked the definitive transition to the phase of endosseous implants (Fig.s 1.2, 1.3)