DENTAL IMPLANTS....
Part One....
A dental implant is an artificail tooth root used in dentistry to support restorations that resemble a tooth or group of teeth.
Virtually all dental implants placed today are root-form endosseous implants. In other words, virtually all dental implants placed in the 21st century appear similar to an actual tooth root (and thus possess a "root form") and are placed within the bone (end - being the Grek prefix for "in" and osseous referring to "bone").
Dental implants can be used to support a number of dental prostheses, including crowns, implant-supported bridges or dentures.
HISTORY...
The Mayan civilization has been shown to have used the earliest known examples of endosseous implants (implants embedded into bone), dating back over 1,350 years before Per-Ingvar Branemark started working with titanium. While excavating Mayan burial sites in Honduras in 1931, archaeologists found a fragment of mandible of Mayan origin. dating from about 600AD. This mandible, which is considered to be that of a woman in her twenties, had three tooth -shaped pieces of shell place into the sockets of three missing lower incisor teeth. For forty years the archaeological world considered that these shells were placed after death in a manner also observed in the ancient Egyptians. However, in 1970, a Brazilian dental academic, Professor Amadeo Bobbio studied the mandibular specimen and took a series of radiographs. He noted compact bone formation around two of the implants which led him to conclude that the implants were placed during life.
In the 1950's research was being conducted at Cambridge University in England to study blood flow in vivo. These workers devised a method of constructing a chamber of titanium which was then embedded into the soft tissue of the ears of rabbits. In 1952 the Swedish orthopaedic surgeon, P.I. Branemark, was interested in studying bone healing and regeneration, and adopted the Cambridge designed "rabbit ear chamber" for use in the rabbit femur. Following several months of study he attempted to retrieve these expensive chambers from the rabbits and found that he was unable to remove them. Per Branemark observed that bone had grown into such close proximity with the titanium that it effectively adhered to the metal. Branemark carried out many further studies into this phenomenon, using both animal and human subjects, which all confirmed this unique property of titanium.
Meanwhile an Italian medical doctor called Stefano Melchiade Tramonte, undersood that titanium could be used for dental restorations and after designing a titanium screw to support his own dental prothesis, started to use it on many patients in his clinic in 1959. The good results of his clinical studies on humans were published in 1966.
Although Branemark had originally considered that the first work should center on knee and hip surgery, he finally decided that the mouth was more accessible for continued clinical observations and the high rate of edentulism in the general population offered mor subjects for widespread study. He termed the clinically observed adherence of bone with titanium as "osseointegration". In 1965 Branemark, who was by then Proffessor of Anatomy at Gothenburg University in Sweden, placed his first titanium dental implant into a human volunteer, a Swede named Gosta Larsson.
Contemporaneous independent research in the United States by Stevens and Alexander led to a 1969 US patent filing for titanium implants.
Over the next fourteen years Branemark published many studies on the use of titanium in dental implantology until in 1978 he entered into a commercial partnership with the Swedish defense company, Bofors AB for the developement and marketing of his dental implants. With Bofors (later to become Nobel industries) as the parent company, Noblepharma AB (later to be renamed Novel Biocare) was founded in 1981 to focus on dental implantology. To the present day over 7 million Branemark System implants have now been placed and hundreds of other companies produce dental implants. The majority of dental implants currently available are shaped like small screws, with either tapered or parallel sides. They can be placed at the same time as a tooth is removed by engaging with the bone of the socket wall and sometimes also with the bone beyond the tip of the socket. Current evidence suggests that implants placed straight into an extraction socket have comparable success rates to those places into healed bone. The success rate and radiographic results of immediate restorations of dental implants placed in fresh extraction sockets (the temporary crowns placed at the same time) have been shown to be comparable to those obtained with delayed loading (the crowns placed weeks or months later) in carefully selected cases.
Some current research in dental implantology is focusing on the use of ceramic materials such as zirconia (ZrO2) in the manufacture of dental implants. Zirconia is the dioxide of zirconium, a metal close to titanium in the periodoc table and with similar biocompatibility properties. Although generally the same shape as titanium implants. Ziroconia, which has been used successfully for orthopaedic surgery for a number of years, has the advantage of being more cosmetically aesthetic owing to its bright tooth -like colour. However, long-term clinical data is necessary before one-piece ZrO2 implants can be recommended for daily practise.
COMPOSITION:...
A typical implant consists of a titanium screw (resembling a tooth root) with a roughened or smooth surface. The majority of dental implants are made out of commercially pure titanium, which is available in 4 grades depending upon the amount of carbon and iron contained. More recently grade 5 titanium has increase in use. Grade 5 titanium, Titanium 6Al-4V, (signifyin the Titanium alloy containing 6% Aluminium and 4% Vanadium alloy) is believed to offer similar osseointegration levels as commercially pure titanium. Ti-6AL-4V alloy offers better tensile strength and fracture resostance. Today most implants are still made out of commercially pure titanium (grades 1-4) but some implant systems (Endopore and Nano Tite) are fabricated out of the Ti-6Al-4V alloy. Implant surfaces may be modified by plasma spraying, anodizing, etching or sandblasting to increase the surface area and the integration potential of the implant.
TRAINING:.....
There is no speciality recognized by the ADA for dental implants. Implant surgery may be performed as an outpatient under general anesthesia, oral conscious sedation, nitrous oxide sedation, intravenous sedation or under local anesthesia by trained and certified clinicians including general dentists, oral surgeons, periodontists and prosthodontists.
The legal training requirements for dentists who carry out implant treatment differ from country to country. In the UK implant dentistry is considered by the General Dental Council to be a postgraduate sphere of dentistry. In other words it is not sufficiently convered during the teaching of the university dental degree course and dentists wishing to practice in dental implantology legally need to undergo additional formal prostgraduate training. The General Dental Council has published strict guidelines on the training required for a dentist to be able to place dental implants in general dental practise. UK dentists need to complete a competency assessed postgraduate extended learning program before providing implant dentistry to patients.
The degree to which both graduate and post-graduate dentists receive training in the surgical placement of implants varies from country to country, but it seems likely that lack of formal training will lead to higher complication rates.
NEXT WEEK......PART TWO.......SURGICAL PROCEDURE
A dental implant is an artificail tooth root used in dentistry to support restorations that resemble a tooth or group of teeth.
Virtually all dental implants placed today are root-form endosseous implants. In other words, virtually all dental implants placed in the 21st century appear similar to an actual tooth root (and thus possess a "root form") and are placed within the bone (end - being the Grek prefix for "in" and osseous referring to "bone").
Dental implants can be used to support a number of dental prostheses, including crowns, implant-supported bridges or dentures.
HISTORY...
The Mayan civilization has been shown to have used the earliest known examples of endosseous implants (implants embedded into bone), dating back over 1,350 years before Per-Ingvar Branemark started working with titanium. While excavating Mayan burial sites in Honduras in 1931, archaeologists found a fragment of mandible of Mayan origin. dating from about 600AD. This mandible, which is considered to be that of a woman in her twenties, had three tooth -shaped pieces of shell place into the sockets of three missing lower incisor teeth. For forty years the archaeological world considered that these shells were placed after death in a manner also observed in the ancient Egyptians. However, in 1970, a Brazilian dental academic, Professor Amadeo Bobbio studied the mandibular specimen and took a series of radiographs. He noted compact bone formation around two of the implants which led him to conclude that the implants were placed during life.
In the 1950's research was being conducted at Cambridge University in England to study blood flow in vivo. These workers devised a method of constructing a chamber of titanium which was then embedded into the soft tissue of the ears of rabbits. In 1952 the Swedish orthopaedic surgeon, P.I. Branemark, was interested in studying bone healing and regeneration, and adopted the Cambridge designed "rabbit ear chamber" for use in the rabbit femur. Following several months of study he attempted to retrieve these expensive chambers from the rabbits and found that he was unable to remove them. Per Branemark observed that bone had grown into such close proximity with the titanium that it effectively adhered to the metal. Branemark carried out many further studies into this phenomenon, using both animal and human subjects, which all confirmed this unique property of titanium.
Meanwhile an Italian medical doctor called Stefano Melchiade Tramonte, undersood that titanium could be used for dental restorations and after designing a titanium screw to support his own dental prothesis, started to use it on many patients in his clinic in 1959. The good results of his clinical studies on humans were published in 1966.
Although Branemark had originally considered that the first work should center on knee and hip surgery, he finally decided that the mouth was more accessible for continued clinical observations and the high rate of edentulism in the general population offered mor subjects for widespread study. He termed the clinically observed adherence of bone with titanium as "osseointegration". In 1965 Branemark, who was by then Proffessor of Anatomy at Gothenburg University in Sweden, placed his first titanium dental implant into a human volunteer, a Swede named Gosta Larsson.
Contemporaneous independent research in the United States by Stevens and Alexander led to a 1969 US patent filing for titanium implants.
Over the next fourteen years Branemark published many studies on the use of titanium in dental implantology until in 1978 he entered into a commercial partnership with the Swedish defense company, Bofors AB for the developement and marketing of his dental implants. With Bofors (later to become Nobel industries) as the parent company, Noblepharma AB (later to be renamed Novel Biocare) was founded in 1981 to focus on dental implantology. To the present day over 7 million Branemark System implants have now been placed and hundreds of other companies produce dental implants. The majority of dental implants currently available are shaped like small screws, with either tapered or parallel sides. They can be placed at the same time as a tooth is removed by engaging with the bone of the socket wall and sometimes also with the bone beyond the tip of the socket. Current evidence suggests that implants placed straight into an extraction socket have comparable success rates to those places into healed bone. The success rate and radiographic results of immediate restorations of dental implants placed in fresh extraction sockets (the temporary crowns placed at the same time) have been shown to be comparable to those obtained with delayed loading (the crowns placed weeks or months later) in carefully selected cases.
Some current research in dental implantology is focusing on the use of ceramic materials such as zirconia (ZrO2) in the manufacture of dental implants. Zirconia is the dioxide of zirconium, a metal close to titanium in the periodoc table and with similar biocompatibility properties. Although generally the same shape as titanium implants. Ziroconia, which has been used successfully for orthopaedic surgery for a number of years, has the advantage of being more cosmetically aesthetic owing to its bright tooth -like colour. However, long-term clinical data is necessary before one-piece ZrO2 implants can be recommended for daily practise.
COMPOSITION:...
A typical implant consists of a titanium screw (resembling a tooth root) with a roughened or smooth surface. The majority of dental implants are made out of commercially pure titanium, which is available in 4 grades depending upon the amount of carbon and iron contained. More recently grade 5 titanium has increase in use. Grade 5 titanium, Titanium 6Al-4V, (signifyin the Titanium alloy containing 6% Aluminium and 4% Vanadium alloy) is believed to offer similar osseointegration levels as commercially pure titanium. Ti-6AL-4V alloy offers better tensile strength and fracture resostance. Today most implants are still made out of commercially pure titanium (grades 1-4) but some implant systems (Endopore and Nano Tite) are fabricated out of the Ti-6Al-4V alloy. Implant surfaces may be modified by plasma spraying, anodizing, etching or sandblasting to increase the surface area and the integration potential of the implant.
TRAINING:.....
There is no speciality recognized by the ADA for dental implants. Implant surgery may be performed as an outpatient under general anesthesia, oral conscious sedation, nitrous oxide sedation, intravenous sedation or under local anesthesia by trained and certified clinicians including general dentists, oral surgeons, periodontists and prosthodontists.
The legal training requirements for dentists who carry out implant treatment differ from country to country. In the UK implant dentistry is considered by the General Dental Council to be a postgraduate sphere of dentistry. In other words it is not sufficiently convered during the teaching of the university dental degree course and dentists wishing to practice in dental implantology legally need to undergo additional formal prostgraduate training. The General Dental Council has published strict guidelines on the training required for a dentist to be able to place dental implants in general dental practise. UK dentists need to complete a competency assessed postgraduate extended learning program before providing implant dentistry to patients.
The degree to which both graduate and post-graduate dentists receive training in the surgical placement of implants varies from country to country, but it seems likely that lack of formal training will lead to higher complication rates.
NEXT WEEK......PART TWO.......SURGICAL PROCEDURE
