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Immediate loading of single-tooth implants appears favorable.
Since their reintroduction into dentistry 20 years ago, titanium implants have traditionally required a 4–6-month period of osseointegration prior to restoration and loading of the implant. However, in recent years, surgeons and restorative dentists have been gradually reducing the time between implant placement and occlusal loading. Now, a recent study published in the International Journal of Oral and Maxillofacial Implants (16:182–192, 2001) suggests almost immediate loading of single-tooth implants after insertion into the alveolus. The sample for this investigation consisted of 53 single-tooth implants placed in 47 subjects. All implants were placed in the maxillary anterior region: 19 central incisors, 25 lateral incisors, and 9 canines. Three weeks after implant placement, provisional crowns were placed on the implants, and they were allowed to undergo normal function. After 7–9 weeks, a permanent crown was placed on the implant. Radiographic evaluations were made at baseline (provisional restoration placement) and at 6, 12, 24, and 36 months after baseline. The authors evaluated the distance between the implant and the marginal bone level over time to determine if immediate loading caused any adverse effects on the surrounding bone. The results showed that the mean change in marginal bone level was 0.4 mm at 12 months. Two implants failed before final crown cementation. Therefore, the survival rate at 36 months was 96.2%. This study strongly suggests that loading of anterior maxillary single-tooth implants 3 weeks after placement does not jeopardize the long-term success rate of the implant restoration.
Narrow-diameter implants are successful in the anterior maxilla. When titanium implants were introduced to the United States in the early 1980s, their application was primarily designed for totally edentulous patients. Usually, 6 implants would be placed in an edentulous mandible and a denture would be permanently fixed to the top of the implants. The diameter of these implants was 3.75 mm, and their strength and ability to resist fracture were tested extensively. However, these implants are often too large to be used as single-tooth replacements for maxillary lateral incisors. Narrower implants (3.25 mm) are easier to place and provide more room for interproximal bone and tissue in the maxillary lateral incisor region. However, there has been some concern about the strength of these narrower implants. A study published in the International Journal of Oral and Maxillofacial Implants (16:217–224, 2001) compared the survival rates of 3.75 mm and 3.25 mm when used to replace maxillary anterior teeth. The sample consisted of 55 patients. In 27 subjects, 3.75-mm-diameter implants were placed, and in the remaining 28 subjects, 3.25-mm-diameter implants were inserted. The survival of the implants was evaluated 6 months and 1, 2, and 3 years after loading. Two of the narrow-diameter implants were lost after 6 months, but no other failures were subsequently observed in either group after that time. Marginal bone loss around the implants was recorded radiographically for both groups and was similar at a mean of 0.4 mm from the first to the last evaluation. In conclusion, it seems that the narrow-diameter implants are strong enough to be used successfully to replace missing maxillary lateral incisors.
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Experts link dental amalgam
fillings with atopic ...
MINAMATA, Japan, Oct 18, 2001 (Kyodo via COMTEX) -- A pair of researchers said
Friday that amalgam, a mercury compound metal used for filling dental cavities,
causes the chronic skin disease atopic dermatitis and other allergic dermatitis
and called for the government to prohibit its use or at least inform patients of
the compound's potential side effects.
Tsunetoshi Shimazu, a Kyoto-based doctor specializing in allergic diseases made the announcement at the Sixth International Conference on Mercury as a Global Pollutant (ICMGP) being held in Minamata, Kumamoto Prefecture, southwestern Japan.
Shimazu conducted a survey with Nagakazu Ko, an Osaka-based dentist, from 1991 to 1998 on 300 allergic dermatitis patients in western Japan who had amalgam in their teeth.
According to Shimazu, after replacing the amalgam in their teeth with other metals or plastic materials, roughly 70% of the patients saw improvements in their dermatitis conditions a year later and about 58% of patients completely recovered from the illness, which is marked by dry, itchy and irritated skin.
Using test tubes, Shimazu and Ko also conducted a survey on the same 300 patients on their lymphocytes' allergic reaction to heavy metals such as mercury which found about 98% of the patients tested positive for a mercury allergy.
In a separate study, Shimazu conducted a survey on about 250 elementary students in Kyoto in 1997 and found about 38% of them had amalgam in their teeth.
While about 48% of those who had amalgam in their teeth suffered from dermatitis only 8% of students who had no amalgam suffered from dermatitis, Shimazu said.
Considering the results of their research, Shimazu concluded that the mercury in amalgam plays a major role in triggering allergic dermatitis.
A tiny amount of mercury dissolved from amalgam is believed to stimulate the skin through sweat or blood, the doctor said.
About 1 ton of mercury for amalgam is used each year in Japan while some nations such as Sweden ban the use of amalgam for pregnant women and small children.
"The reality is that patients receive medical treatment with amalgam believing it is silver," Shimazu said. "Measures to counter allergies should first focus on removing the causes, not just relying on steroids. The government should seriously consider whether to ban the use of amalgam."
DENTAL PROBLEMS LINKED TO OTHER
AILMENTS
Oral bacteria, in some studies, have been associated with heart disease,
stroke, diabetes and the birth of pre-term underweight babies, said Connie
Hastings Drisko, assistant dean for research at the University of Louisville
(Ky.) School of Dentistry, in a presentation at the American Dental
Association's Annual Session on Oct. 15. For example, mothers with periodontal
disease may be six to seven times more likely to have a premature, underweight
baby. There is also evidence to support an association between gum disease,
heart disease, and stroke. Diabetics are at significantly higher risk for severe
gum disease. When exposed to the same type of bacteria as non-diabetics, the gum
tissue of diabetics becomes much more inflamed. What's more, treating the
diabetes will slow down the progression of gum disease, and diabetes is more
easily controlled if the periodontal disease is treated. "Dentists are
well-versed in handling oral health conditions, and currently help screen
patients with diabetes," Drisko states. "In the future, dentists may
have an even more important role in screening for other conditions such as heart
disease and stroke as the link is strengthened between oral and overall
health." A Future Without Drills and
Fillings? Not Far ... According to Dr. Slavkin, dentistry will rapidly evolve from dependency on
mechanical and surgical solutions for treating disease, to "bio"
solutions in which conditions are treated at a molecular level. For example,
instead of using fillings to repair cavities, a dentist will someday modify
the specific bacteria in a person that cause dental disease in the first
place. A simple swab from inside the mouth will provide enough DNA to develop
individualized dental treatments in the future.
"The mouth is a portal to the body," Dr. Slavkin says. "Many
systemic diseases and disorders manifest themselves in the mouth."
Several thousand structural and/or regulatory genes are required for the
development and maintenance of oral, dental and craniofacial cells, tissues
and structure, Dr. Slavkin says. Variances within these multiple genes can
lead to disease or disorders.
Future DNA-based oral diagnoses will certainly aid children who are born
with genetic mutations that are not apparent at birth but show up during later
stages of development, according to Dr. Slavkin.
For instance, a gene mutation responsible for a rare disease called
Papillon-Levere syndrome (PLS) often causes children to lose all of their baby
teeth by the age of four and all of their adult teeth by the age of 14 due to
an abnormal inflammatory response to oral infections. In the future, using the
child's DNA sample to provide early identification of this syndrome, dentists
would be able to intervene with bio solutions before the teeth are lost.
"The interface between the human genome, information technology, and
biotechnology will direct the future treatment of oral health in this new
century," Dr. Slavkin concludes. Researchers look for owners
of baby teeth The teeth were found in a dark, musty ammunition bunker at the Tyson
Research Center on the university campus.
Scientists now want to know whether fallout from the Cold War tests led to
cancer and other health problems.
The teeth were part of the St. Louis Baby Tooth Survey, in which thousands
of children opted to stiff the Tooth Fairy and instead donated their teeth to
science. The study eventually helped persuade government officials to ban
atmospheric testing.
The teeth were collected between 1959 and 1970 by the Greater St. Louis
Citizens Committee for Nuclear Information. They were accompanied by a card
with name, address, birth date and other information.
In return, the children received a thank you note and a button reading,
"I gave my tooth to science." Some 300,000 teeth were collected,
most from the St. Louis area.
In studying the teeth, biochemist Harold Rosenthal at Washington
University's School of Dentistry determined the level of strontium 90 rose and
fell in coordination with the bomb tests. The study ended when President
Richard Nixon cut funding in 1970.
Joseph Mangano, national coordinator of the Radiation and Public Health
Project, said the group is now trying to match up the teeth with their owners
to determine the long-term health effects.
Copyright 2001 by United Press International.
KANSAS CITY, Mo., Oct 16, 2001 (ASCRIBE NEWS via COMTEX) -- Imagine a visit to
the dentist where cavities and gum disease can be prevented by using gene
therapy. Imagine your dentist being able to repair or regenerate your teeth
using your own DNA. Such a future is not far away, predicts Harold C. Slavkin,
D.D.S., dean at the University of Southern California School of Dentistry, in
a presentation at the American Dental Association's Annual Session on October
16.
ST. LOUIS, Mo., Nov 09, 2001 (United Press International via COMTEX) --
Researchers at Washington University are looking for the owners of 85,000 baby
teeth collected as part of a study to determine whether children were affected
by radioactive fallout from nuclear bomb tests.