Mayan Esthetic Dentistry: Using Modern Technologies to Link the Past to the Present

Also, reading this article and its description of how the use of current digital imaging technologies helped recreate a Mayan skull and then a dental arch reminded me of discussions I had with Dr. A. John Gwinnett, a pioneer of dental adhesion who trained with Dr. Michael Buonocore at the Eastman Dental Center in Rochester, New York. Dr. Gwinnett related to me his using in the late 1970s some of the earliest scanning electron microscopy (SEM) devices used in dentistry to characterize the surfaces of etched enamel and dentin to gain insights when investigating tool marks on stone reliefs dating from the late Chalcolithic period to the early Iron Age (c. 3000-400 B.C.). These marks portrayed the use of drills and the drilling techniques employed. Not only did Dr. Gwinnett publish extensively in the dental literature, but he also wrote archeological research articles on the stone age.

While this article is certainly atypical for Compendium, readers may appreciate how the techniques and digital imaging technologies used were able to link the past to the present. It also may trigger thought-provoking and creative ideas for the treatment of present-day patients. I invite you to read this article and enjoy a break from traditional dental readings.

- Howard E. Strassler, DMD, Editorial Advisory Board Member, Compendium

Esthetic dentistry is evolving rapidly with the aid of technological advances. This swift progression overshadows the beginning of dental esthetics, which astonishingly began about 1,500 years ago. Indeed, pre-Columbian civilizations, especially the Mayas, performed craniofacial orthopedics and dental treatments for esthetic purposes. The final results were astounding, both visually and longevity-wise. Unfortunately, the remaining artifacts are heavily damaged, and this leads researchers to establish only hypotheses on the means used at that time. This article explores how Mayan esthetic dentistry can be resuscitated with the use of modern tools that are readily accessible to today's practitioners. Through different workflows, the author has reconstructed a Mayan skull and Mayan smiles using 3D imaging, intraoral scanning, and 3D printing as well as a manual artistic touch. The utilization of modern technological equipment makes it possible to meet virtually any esthetic demand, whether current or ancestral.

Mexico is a lush country with touristic places, gastronomy, and culture. It has a rich history dating back to the dawn of humanity with pre-Columbian civilizations. Many people have heard of the Aztecs and Mayas but may not realize that these people performed dental treatments.¹ Books and films primarily depict only the spectacular or violent aspects of these civilizations, including human sacrifices, but do not commonly show that the Mayas, for example, performed esthetic dentistry in their day.²

The Mayan civilization is best known for the remains of the past, which are preserved as archaeological sites found on the Yucatan peninsula. For example, more than just a pile of stones, the Mayan pyramids represent a true astronomical alignment. In Chichen Itza, the structure of the Kukulcan temple consists of 365 steps, one for each day of the year, and the orientation of the building is such that during the solstice, the shadow of the steps draws the shape of a snake that descends from the top of the pyramid. This optical effect prefigures the descent to earth of the god Kukulcan, the feathered serpent.

In addition to mastering the sciences, the Mayas were highly sophisticated in art. Their sculptures and paintings are in the form of statues, vases, mortuary masks, and jewelry. Many artifacts have been able to cross the time and reach today's society to reveal the peoples' mastery of shapes and materials. One can easily imagine that if a civilization mastered the sciences and the arts, medicine was within reach. Surrounded by flora and fauna, the Mayas were able to draw all the quintessence of plants and animals to build an elaborate pharmacopoeia useful not only to heal human beings but also perform sacred rites.³ Dentistry has not been overshadowed, and their mastery of the craniofacial sphere is simply impressive.

By observing the human representations of Mayan remains, one can notice recurrent characteristics in the craniofacial profile (Figure 1). The face is pulled up giving the skull an ovoid shape. The nose is elongated, and the forehead is flat with a nasofrontal angle so open that the nose seems to be continuous with the top of the skull. These criteria are found in representations of adult men and women as well as children. The reason is simple: The Mayas gave their children, from a very young age, rigid plates to direct cranial growth and provide the head a specific shape.⁴ This secular tradition is similar to craniofacial orthopedics for purely esthetic purposes. The voluntary deformation of the skull aspect was done for the purpose of ethnicity and individual identity.⁵ Among the Mayas, beauty consisted of having a furrowing forehead and an ovoid skull.⁶

Beyond the esthetic aspect, the Mayas amaze with their anatomical knowledge, including the existence of fontanelles, soft tissue between the bones of the skulls, allowing growth of the skull of the child after delivery. This medical knowledge is explained by their funerary practices. The Mayas manipulated the bodies of their dead to make post-mortem modifications such as decorative trepanning on the skull.⁷ These manipulations probably allowed for analysis and close study of the human anatomy, which helps explain their mastery in medicine as well as in cardiectomy.

If mastering craniofacial growth was part of the therapeutic and artistic arsenal of the Mayas, one can easily imagine that dentistry was fairly routine for them. For proof, remains on the Mayan human include multiple and varied dental modifications that extend beyond simple therapeutic ones (Figure 2). Different types of dental modification classifications have been described, ranging from simple reduction of the incisal edge, to the complex combination of ameloplasty, and the insertion of a precious stone inlay.⁸ It leads one to wonder why and how these alterations were made.

The modifications made to the teeth concern almost exclusively anterior teeth, from canine to canine, and mainly maxillary teeth.² In addition, these changes are visible, ie, they appear on the buccal surface of the tooth. Obviously, the driving motivation was esthetics. As with craniofacial orthopedics, dental modifications often have an ornamental purpose, as one's teeth are integral to the social and professional life of the individual, and such modifications follow a cultural tradition.⁹ In modern-day dentistry, esthetics are enhanced with the placement of veneers to improve an individual's smile and even quality of life. In Mayan times, dental artists made cranial and dental modifications to follow ancestral rites¹⁰ and make their mark on history. The Mayan armamentarium included many materials available in the Yucatan peninsula or carried by travelers of that time. Abrasive materials such as quartz or flint were used, but so were precious stones such as jade and hematite.² These dental jewels have crossed time and space, so that 1,500 years later they are still in the mouth, or rather what is left of it.

The Mayas knowledge was extensive, as was their desire to share their knowledge. All of their culture was written in encyclopedias. These books were in a form that was folded like an accordion. These pictographic manuscripts bore a name that was both mystical and mysterious: the Codex. Mayan writing is a combination of glyphs and symbols that relate their customs.¹¹ Unfortunately, with the arrival of the conquistadors in the 16th century, the priests who accompanied them considered these writings to be sacrilegious artifacts, and gigantic bonfires were set, destroying much of the recorded Mayan knowledge. Today, only three Maya codices are left.¹² Two of them are in a state of disrepair such that they are non-manipulable. The third one is considered the most beautiful, and it reports the rites associated with the Mayan calendar. Regrettably, no mention is made about medicine, pharmacology, or Mayan dentistry.

Today's modern dentistry helps restore patients' smiles and self-esteem. But, moreover, unbeknownst to most people is that today's technological tools are capable of restoring artifacts and reviving ancestral knowledge. In the absence of a Maya codex detailing the Mayan dental works, the author presents four different workflows to resuscitate Mayan esthetic dentistry.

In this first workflow, a Mayan skull inspired by their craniofacial plastic criteria will be recreated. First, the acquisition of a skull is made by means of a CBCT (iCat^™ FLX V10, Kavo Dental, kavo.com). The result is a DICOM file that contains all the necessary information in the form of pixels in gradual gradation in Hounsfield units. The less luminous pixels correspond to empty spaces like air, while the luminous pixels correspond to hard tissues like bone and teeth. The reconstruction software makes it possible to visualize the result in the form of a 3D object. By choosing the appropriate window, it is possible to hide the soft tissues and let only the mineralized tissues appear. A massive face with a fine resolution is obtained (Figure 3). The result obtained is exported in STL format for easy manipulation with software programs.

In a second step, modifications are made virtually. With a mouse click, the frontal bone may be flattened to lengthen the occipital bone and pull the parietal bones upward, while the cranial volume is maintained equally (Figure 4). All of these changes are made by computer, and the operator is able to view the final result immediately. The third step is to print the object in 3D. The computer project is exported in STL format (Figure 5) to be sent to a 3D printer (Solflex 650, Voco, voco.dental/us). A transparent resin (V-Print ortho, Voco) was used to produce a luminous artifact resembling a crystal skull: a Mayan skull printed in 3D (Figure 6).

In today's contemporary clinical practice, this technology is well suited to craniofacial orthopedics. Orthodontists and maxillofacial surgeons can work finely on their clinical cases and perform simulations ranging from simple 3D visualization on a computer to a 3D-printed object. Whether in the case of Angle Class III malocclusion or facial asymmetry, patients can now see and even touch what their face will look like after treatment.¹³

A second workflow will be used to reconstruct a dental arch following the esthetic canons of Mayan dentistry. As in the first workflow, the initial step requires an acquisition. An intraoral scanner (CEREC^®, Dentsply Sirona, dentsplysirona.com) is used to record the maxillary arch in all its details. Since a recent update, the software (CEREC SW 4.5) associated with the intraoral scanner makes it easy to export the scan in STL format to be printed in 3D (Figure 7). After a base for the dental model is created with a 3D modeling software, the STL file is sent to the 3D printer (Solflex 170, Voco). The model is printed (V-Print model, Voco) in a shade close to A2 (VITA North America, vitanorthamerica.com) (Figure 8).

To achieve a wax-up that is as natural looking as possible, a digital smile design (DSD)¹⁴ is performed beforehand. The incisors are modified according to a Mayan pattern: The lateral incisors undergo a horizontal incisal reduction, while the central incisors are altered to create a mesial step. The incisors and canines receive a spherical inlay in the buccal aspect (Figure 9). The inlays may either be completely flat in the continuity of the buccal surface, form a spherical outgrowth while remaining within the confines of the cavity, or form a spherical outgrowth that exceeds the limits of the cavity.²

Following the DSD, characterization is created with fluid composite (Admira Fusion, Voco), with more chromatic shades used for the posterior teeth (A3.5 for the molars, A3 for the premolars) and less chromatic shades for the anterior teeth (A2 for the canines, A1 for the incisors). Composite tints (FinalTouch, Voco) are used in the grooves and embrasures. The gingiva is reproduced with a pink composite (Amaris Gingiva, Voco). Finally, the gemstone inlays are made of colored composite (Twinky Star, Voco) in green to imitate jade and blue to imitate turquoise. The final result is a dental arch that gives the realistic impression of a Mayan dentition with natural flaws and uncanny beauty (Figure 10).

Today's composites may be used to effectively recreate quite realistic results, giving clinicians the means to design smiles that patients often strongly desire. These effectual results can be achieved in a predictable and esthetic way.

In the third workflow, a mock-up will be designed to try the Mayan smile. The initial stage remains the same, ie, acquisition of the dental arch by means of an intraoral scanner (TRIOS^®, 3Shape, 3shape.com). The STL file is exported from the acquisition software to be imported into a design software (Figure 11).

The next step is to digitally create the Mayan smile. In the previous workflow, the Mayan smile was designed manually based on a simulation of the smile. In this specific case, after a DSD is prepared, the STL file and the simulation are sent to a digital prosthesis laboratory. The dental technician can then virtually create a dental model of the Mayan arch (Figure 12), which includes all necessary features: the incisal edge reduction of the laterals, the mesial step of the centrals, and the buccal inlays. The project is sent by email in STL format to be printed in 3D (Solflex 170) (Figure 13).

Next, the 3D-printed wax-up is transferred to the mouth. A silicone key (V-Posil, Voco) is used to record all the details (Figure 14). The silicone key is filled with a self-curing composite (Structur A1, Voco) and placed in the mouth. The result is simply fascinating: a natural Mayan smile (Figure 15). All of these steps allow for the revival of an esthetic style that was thought to be forgotten.

From a clinical standpoint, the mock-up is a daily tool in esthetic dentistry.¹⁵ It offers the patient the opportunity to try his or her smile before engaging in the therapeutic process. Whether the demand is conventional or unusual, current technological tools enable clinicians to meet or even exceed patient expectations when the workflow is properly mastered.

In this last workflow, the mock-up is directly printed in 3D. Indeed, in the previous workflow, the mock-up had two major drawbacks: the implementation can be long and tedious, and the mock-up must be destroyed to be removed. Once again, technology offers healthcare professionals a solution that overcomes these barriers. From an intraoral scan and based on the DSD of the expected smile, the dental technician can design a mock-up directly printable in 3D (Figure 16). Depending on the type of resin and printer used, the thickness of the 3D printing may be reduced to obtain a thin, comfortable mock-up. In the case of the Mayan smile, the mock-up was printed first (Figure 17), and then the dental jewel was made (Twinky Star) (Figure 18). The mock-up is then inserted in the mouth easily in just a few seconds (Figure 19). It can be removed easily after the photograph session and reused later.

Trying a mock-up is good; printing a mock-up is better. Again, the full potential of technology is displayed, as patients are able to try the smile they desire. The finesse of the resin printed in 3D combined with the precision of the computer design led to a real dental jewel, the quintessence of esthetic dentistry.

The Mayas showed their supremacy in dentistry by performing dental procedures that have remained through the ages. Even if the esthetic canons are not applicable to today's modern society, it is clear that the technical and biological mastery of these people has yielded a fascinating result. Esthetic dentistry has its source in central America more than 1,500 years ago. Rather than falling into oblivion, Mayan dentistry has been resurrected thanks to current technological tools. By following four simple steps-scan, design, print, perform-it is possible to create lifelike artifacts. This workflow that is applicable to modern dentistry demonstrates that it is possible to perform natural and accurate dental restorations. Perhaps the smiles of today's dental patients will endure time like those of the Mayas.

The author thanks Jonathan Pellerin, CDT, Laboratoire Dentaire de la Mauricie, in Trois-Riviéres, Quebec, Canada, for his talented laboratory work in this article; Dr. Silvia Jarchow and her team at Voco GmbH for their intellectual and material support; and Dr. James Robson for his support proofreading this article.

Yassine Harichane, DDS, MSc, PhD
Private Practice, Les Sables Olonne, France