What is a Prosthodontist
Prosthodontics, also known as dental prosthetics or prosthetic dentistry, is a branch of dentistry which specializes in the use of oral prosthesis to replace missing teeth, solve jaw problems, and other related problems. Their expertise extends beyond that, as they are also involved in cosmetic procedures involving a person’s smile. Specifically, the American Dental Association defined prosthodontics as “the dental specialty pertaining to the diagnosis, treatment planning, rehabilitation and maintenance of the oral function, comfort, appearance and health of patients with clinical conditions associated with missing or deficient teeth and/or oral and tissues of the jaw and the face using substitutes that are safe to use around living tissue”. Prosthodontics comes from the new Latin word “prosthesis” and the Greek work “odont”, meaning teeth.
Similar to other medical fields, prosthodontics requires a completion of a bachelor’s degree. No specific bachelor’s degree is required to study prosthodontics, but some courses are required. Specifically, these courses are Biology, Organic and Inorganic Chemistry, and Physics. Other recommended courses include Anatomy, Psychology, Biochemistry and Mathematics. While a strong scientific background is necessary, some dentistry schools in America are known to have a preference for degrees in Business, Foreign Language, and the Humanities.
Following the completion of a bachelor’s degree is an admission exam for dental schools. In America, this is called the Dental Admission Test (DAT), provided by the American Dentistry Association(ADA). The exam is composed of 280 questions on a variety of subjects and skills. The exam is divided into Biology, General Chemistry, Organic Chemistry, Reading Comprehension, Perceptual Ability, and Quantitative Reasoning. The DAT exam guide published on the ADA website has a specific breakdown of what is covered in each part. It also affirms that the Reading Comprehension examination will cover scientific articles, knowledge of the articles is not required to answer the test. The ADA’s Department of Testing Services offers a purchasable practice exam based on previous iterations of the exam. A variety of websites also offer free DAT practice exams. The exam can be retaken any number of times, with a required 90-day period in between test attempts. A retest after the third attempt will require evidence of an attempt to apply to a dental school.
Once the admissions test has been passed, the aspiring prosthodontist must apply to a dental school, in which the student will spend about 4 years. Similar to medical school, the first 2 years of dental school is used for coursework on a variety of topics in anatomy, epidemiology, diagnostic techniques, treatment methods, and so on. The last 2 years of dental school is spent on the practical application of the skills and knowledge gained over the first 2 years on real patients. This is done under the supervision and guidance of experienced dentists.
Following dental school is a licensure exam. In America, these are the 2-part National Board Dental Examinations and the National Board Dental Hygiene Examination. These examinations establish the standards of knowledge, skills, and readiness of dentistry practitioners. The examinations generally require a prerequisite graduation from a dental school, and is composed of a written exam and a clinical exam.
Upon completion of the licensure exam, aspiring prosthodontists must complete a prosthodontics residency program. This program builds upon the knowledge established in dental school to establish the skills and knowledge required to practice prosthodontics. This will generally involve extensive hands-on experience under a practicing prosthodontist, as well as laboratory work, research, and lectures.
While the completion of a residency program is sufficient, many prosthodontists opt to take a certification exam from a board of prosthodontics. This certification requires a prosthodontist to constantly continue their professional development, as maintaining a certificate requires a prosthodontist to take a certification exam every 8 years. This makes a board certified prosthodontist more appealing to employers.
Roles and Responsibilities
A prosthodontist is a dentist who specializes in the use of oral prosthesis. Their roles revolve around replacing or restoring teeth. They use a wide variety of techniques and tools to respond to different oral conditions, be it for a single tooth or the entire line of teeth. They can even respond to oral birth defects like cleft pallets.
Tooth decay is a natural phenomenon that destroys teeth, specifically the harder parts of teeth. This occurs when sugary food reacts with plaque, a sticky film of bacteria that surrounds the teeth. Sugary food causes plaque to release acids that destroy the teeth. This can cause tooth pain, making eating difficult. For most cases, tooth decay can be cured with by cleaning out the decayed area and filling it up with other material, such as gold, silver, or plastic composites. Any dentist is trained to carry out such a procedure. However, when tooth decay is not managed early, it can begin to decay tooth roots. Tooth roots are much more susceptible to decay and are sensitive to temperature and touch, so the area becomes extremely uncomfortable, especially when eating. When this happens, a prosthodontist is required to respond to the condition. One of the options that a prosthodontist may opt for is a dental implant.
There are three types of dental implant. The root implant is the most commonly used type of the three. These implants are metal or ceramic cylinders placed into the jawbone that replace the missing tooth roots. These are as strong as regular tooth roots and mimics its regular size and shape, making it blend in with the rest of the teeth. Local anesthesia is first applied in the area required, then the implant is placed into the jawbone. The affected area is then left to heal, while the implant integrates with the bone. When the wounded area is completely healed, a new tooth is placed on the dental implant. This entire process can take between three to eight months. When the jawbone is not wide enough to support a root implant, a plate implant is used instead. It is long and thin, as opposed to the root implant’s wide design. The plate implant is attached using the same procedures as the root implant. When the jawbone cannot support either implant, a subperiosteal implant is used. This is a long metal structure that is lined around the jawbone. This carries a significant risk, as failure will result in significant bone loss. The implant will also be eventually rejected by the jaw, requiring constant monitoring and adjusting.
Another option that a prosthodontist may use when restoring missing teeth is a denture. These are specially crafted to match the specific appearance of the patient’s teeth to look and feel as natural as possible. There are two types of dentures, a removable partial denture and a complete denture. Removable partial dentures are used when a patient still has some teeth. These dentures fit into the missing teeth and cover the gums and bone where the teeth are missing, making them appear natural. When all of the teeth are broken, a complete denture is required. Complete dentures replace all of the teeth with artificial ones and may rest on dental implants to improve stability. Both implant types may take some time to get used to, but speaking and eating should eventually feel natural. These dentures are made out of pink plastic around a metal frame. The denture teeth are made of plastic or resin.
Crowns and Bridges
When teeth are intact but become disfigured due to decay, chipping, or many other sources of damage, a prosthodontist may use a crown to restore tooth function and appearance. A crown, otherwise known as a cap, can be made out of porcelain to mimic a tooth’s color, or metals like gold for durability. Porcelain-fused-to-metal crowns are also available for use. These are crowns with metal cores for durability and porcelain exteriors for appearance. The tooth would first digitally or manually measured to use as basis for the construction of the crown. Then, the tooth to be covered would be drilled to allow the crown to fit on it. If there is not enough tooth material left, a filling may be necessary. Then, the crown is applied on the tooth sealed permanently. This operation is generally done over two or three appointments. If the permanent crown is not yet applied, a temporary crown is used to protect the tooth from potential harm.
When a single tooth is completely destroyed, bridging techniques can be used to replace it. Instead of one crown tooth, a bridge is at least three crown teeth attached adjacent to each other, with the crown for the missing tooth in the middle. This involves the drilling down of the two adjacent healthy teeth to support the bridge. The same techniques can be used for multiple teeth, dependent upon the number of remaining healthy teeth, the support available from the bone, and the location of the missing teeth. For three missing teeth, four healthy teeth are required to become supports for the bridge, and so on.
A veneer is commonly used for aesthetic purposes, but may also be used to correct damaged teeth. Compared to a crown that surrounds a tooth, a veneer is a shell that rests in front of a tooth. The operation is mostly painless, and would therefore not require anesthesia. To start, the damaged tooth is cut to fit the shape of the veneer. This keeps the tooth from looking too bulky. The veneer is then crafted from the required shape and color of the rest of the teeth. On a second appointment, the veneer is applied on the tooth and hardened. These can be used instead of crowns, especially when sufficient support is available.
Cleft Palate Treatment
A cleft palate is a birth defect that looks like an opening in the roof of the mouth. This occurs when the mouth does not seal completely while development is occurring in the womb. This makes speaking and eating difficult. Many cases of this birth defect can be treated with surgery. Some cases require a prosthetic before or instead of a surgery, especially for cases where the cleft is too wide to operate on. A prosthesis in this case is meant to facilitate speech, allow for an easier chewing action, maintain aesthetic image, and to help the patient cope with the defect psychologically. Since some teeth may not grow in a patient who has recovered from a cleft palate, a prosthodontist may also be called upon to create and attach new teeth to the patient.
Temporomandibular Joint Dysfunction (TMD)
The temporomandibular joint is a joint that connects the lower jaw to the rest of the head. These joints are responsible for the movement of the jaw, which facilitates speech and eating. Behind this joint are many tissues that are lined with nerves. TMD is a painful disease that occurs when the temporomandibular joint does not function correctly. TMD will cause these tissues to become inflamed, causing significant pain from any amount of pressure. A common treatment for TMD is a bite guard, also called a stabilization or occlusal splint. The bite guard is made of plastic and is used to correct and maintain the position of the joint. It is applied on the upper or lower teeth. Aside from that, painkillers may be given to provide temporary relief. In some cases, anti-inflammatory medication may also be given
Jaw pain alone does not signify that a person has TMD. One specific symptom of TMD is a clicking, grating, or popping sound that can be heard around the joint when one talks or chews. While a blow to the jaw is a significant cause of TMD, its causes are still unknown. Some believe that stress may be a factor in getting TMD. In most cases, the pain from TMD subsides and goes away without treatment in time.
Sleep apnea is described as the lungs’ inability to provide the oxygen that the body needs. This occurs due to a temporary pause in breathing while sleeping. This pause lasts between seconds and minutes. As a result, a person with sleep apnea may experience restlessness during sleep, as well as tiredness while awake. Snoring may also occur in a person with sleep apnea. Generally, a person with sleep apnea is unaware that they suffer from sleep apnea.
The generally accepted treatment method is a continuous positive airflow pressure (CPAP) machine. This machine is a mask that goes over the nose and mouth while sleeping. It provides a constant flow of oxygen into the lungs, even when the pause in breathing occurs. Many people find this treatment unappealing due to the bulkiness of the machine and its associated discomfort while sleeping. Instead, a prosthodontist might offer an oral appliance that moves the lower jaw or the tongue forward. This allows an easier flow of air while sleeping. The oral appliance is only applicable to milder cases of sleep apnea. Severe sleep apnea should be treated with a CPAP machine.
The history of prosthodontics can be traced back to Egypt around 2500 B.C.E, although historians are still in debate regarding the specific details regarding their methods and practices. A tomb in El Gizeh was discovered by Herman Junker in 1927 containing a skull with gold wire woven around the molars. Aside from being aesthetically pleasing, gold is a good candidate for tooth restoration projects due to the fact that it is extremely durable, a fact that makes gold still applicable in dental prosthetics today. Gold does not react to food, water, or air. It also does not rust. Artificial teeth were also found in the mouths of mummies. These teeth were made from a variety of materials, including wood, gold, ivory, and brass.
Gold wire was also used by the early Phonecians to restore teeth. Gold wire was found in the jaw of a woman going through six teeth, two of which did not belong to her. This represented one of the very first steps in modern prosthodontics. Similar findings were discovered in Ancient Roman archaeological sites. Gold crowns were also found there, the first known use of its kind.
Beyond those finds, very little progress was found in dental prosthetics until the 18th century. Pierre Fauchard, a French dentist, made significant progress in the field of dental prosthetics through his research and application of restoration techniques. He had done one tooth restorations and almost complete mouth restorations ahead of his peers. He was the first to use what he called a “tenon”, a structure inserted into the roots of teeth to secure fixed partial dentures, not unlike the structures used in dental implants today.
At the time, replacement teeth were gathered from a variety of sources. These included teeth from other humans, animal teeth, ivory, and porcelain teeth. Obtaining replacement teeth was difficult at the time. Known sources included the poor who were willing to sell their teeth, grave robbed teeth from the dead, and teeth extracted from soldiers who died in war. These teeth were used as crowns, much like the way crowns are applied today. Animal teeth was vulnerable to decay due to its reaction to saliva and took significantly more effort and time to sculpt and shape to fit a human mouth, so it was not very popular. Hippopotamus ivory was used more widely for its strength. Elephant ivory and bone taking second place due to its porous nature, making the replacement teeth weak to strain. The first successful manufacturing of porcelain dentures is credited to Duchateau, an apothecary. In 1774, he got help from porcelain manufacturers to build the dentures. In 1787, Dubois de Chemant was the first to use the same technology to apply porcelain teeth to a human mouth. However, most of his restoration work ended in failure. Geuseppangelo Fonzi improved upon the design. His design looks similar to what is being used today, single teeth with platinum hooks soldered to a metal base.
The next advances in dental prosthetics occurs in America, where porcelain teeth were introduced in 1817. A few years after, porcelain manufacturers began competing in the manufacturing of porcelain teeth, all of them attempting to mimic the color and strength of human teeth. It was around this time that the Dentists’ Supply Company was created, featuring a unique process that created porcelain teeth that had the necessary qualities to mimic human teeth.
At the time, a suitable material to create the base of dentures had yet to be found. Throughout history, wood, ivory, porcelain, silver, gold, and a variety of metals were used to form denture bases, but none could fit well with the human jaw. Silver and gold had the best fit, but were too expensive for most people. In the middle of the 19th century, the process of creating rubber was discovered and then improved by Charles Goodyear and Nelson Goodyear, who together formed the Goodyear Company. In 1855, they established a patent for the use of vulcanite, a kind of hard rubber, to form the base of dentures. While it was not a good choice aesthetically, vulcanite fit well around the mouth, and could therefore be worn in relative comfort. Vulcanite was also extremely cheap, which meant dentures became more accessible to people. This made vulcanite the preferred denture base for over 75 years. The Goodyear company’s patent was licensed out to many dentists, who had to pay a fee to use vulcanite dentures in their practice. This patent would eventually be owned by Josiah Bacon, who increased the licensing price of the method. This brought upon him the anger of the dentistry community, as well as the general public. He was eventually shot and killed by a dentist that he was prosecuting for the use of his method.
Methyl methacrylate became the denture base of choice around 1937, and still remains in some use today alongside acrylic denture bases. It had a similar color to the gums, which was further improved by adding nylon threads to its construction to break its solid pink color. At its inception, there were significant problems regarding its manufacturing and storage methods. A significant amount of research efforts were poured into the material, which resulted in the dentures that can be regularly seen today.
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