Why some dental implants work and others don't

Each year, about 500,000 North Americans get dental implants. If you are one of them, and are preparing to have an implant, it might be a good idea to start taking beta blockers, medication that controls high blood pressure, for a while. And to stop taking heartburn pills.

A body of research from McGill led-teams indicates that in order to raise the odds that dental implants will attach properly, there are clear benefits to taking certain common medications and avoiding others.

Bone cell growth, healing and death

"The success of procedures like dental implants depends mainly on how the existing bone accepts the implants to create a connection between the living bone and the surface of the implant," says Prof. Faleh Tamimi, who teaches in the McGill Faculty of Dentistry, and is the senior author on a number of papers published on the subject in recent weeks. "Because some medications affect bone metabolism and the way that bone cells heal and multiply or die, they can have an important effect on the success of implants."

The McGill research team reviewed data about the integration of dental implants gathered from over 700 patients who were operated on at the East Coast Oral Surgery Clinic in Moncton, New Brunswick between 2007-2015. They then confirmed the results they saw in human patients through studies in rats.

Implications for hip and knee replacements

"We believe that this research may have implications for orthopedic interventions such as hip and knee replacements, because the same mechanisms of bone cell growth break down, and healing take place in all the bones in the body," says Tamimi. "Our work with implants in rats suggest that this is indeed the case, but further research will be needed to confirm it."

Drugs that aid integration of implants - Beta blockers

Conclusions are based on 1499 dental implants in 728 patients between Jan. 2007 -- Sept. 2013 at the East Coast Oral Surgery in Moncton, New Brunswick

• 327 implants were in 142 people who took beta blockers for hypertension
• 1172 implants were in 586 people who didn't take beta blockers
• Failure rates of implants for people using beta blockers was 0.6%
• Failure rates of implants in people who don't take beta blockers was 4.1%
• More than 640 million patients around the world take beta blockers to control hypertension.

"We carried out this study because we knew that beta blockers have been reported to increase bone formation," says Prof. Tamimi from McGill's Faculty of Dentistry. "So we thought it was possible that they would also decrease the risk of failure of dental implants. However we didn't expect that there would be such a clear difference in the failure rates for implants between users and non-users of beta blockers. Randomized clinical trials will need to be carried out as well as other studies of large numbers of patients to investigate this phenomenon in more depth."

Drugs that impede integration of dental implants - Heartburn treatment

Conclusions are based on 1773 dental implants in 799 patients between Jan. 2007 -- Sept. 2015 at the East Coast Oral Surgery in Moncton, New Brunswick

• 133 implants were in 58 people who took heartburn medication
• 1640 implants were in 741 people who don't take heartburn medication
• Failure rates of implants for people using heartburn medication were 6.8%
• Failure rates of implants for people not taking heartburn medication were 3.2%
• More than 20 million Americans, about one in 14 people, take heartburn medication.
• Heartburn medication is rapidly becoming the third most prescribed pharmaceutical product worldwide, especially for elderly people, who take it either on an occasional or long-term basis.

"Scientists already knew that drugs for heartburn reduce calcium absorption in bones and generally increase the risk of bone fractures," says Faleh Tamimi, of McGill's Faculty of Dentistry. "That is why we wanted to look at how it affects the integration of implants and bone healing after this type of surgery. But we didn't expect to find that the negative effects of these type of drugs would be as great as they are. Further work will need to be done to find the appropriate dosages and time periods that people should take or avoid these medications."

To read the full articles on effects of Beta blockers

In humans: "Antihypertensive medications and the survival rate of osseointegrated dental implants: A cohort study" by X. Wu et al in Clinical Implant Dentistry and Related Research: http://onlinelibrary.wiley.com/doi/10.1111/cid.12414/full

Regular dental visits may help prevent pneumonia

That twice-yearly trip to the dentist could do more than keep teeth and gums healthy: It may decrease the risk of pneumonia by reducing bacteria in the mouth, suggests research being presented at IDWeek 2016™.

Nearly one million Americans become ill with the infection every year and 50,000 die. While it is more common among older people and those with conditions such as AIDS or lung disease, anyone can get pneumonia. Based on an analysis of a national database of more than 26,000 people, the new research found that people who never get dental checkups had an 86 percent greater risk of pneumonia than to those who visit the dentist twice a year.

"There is a well-documented connection between oral health and pneumonia, and dental visits are important in maintaining good oral health," said Michelle Doll, MD, lead author of the study and assistant professor of internal medicine in the Division of Infectious Disease at Virginia Commonwealth University, Richmond. "We can never rid the mouth of bacteria altogether, but good oral hygiene can limit the quanitities of bacteria present."

Researchers analyzed data obtained from the 2013 Medical Expediture Panel Survey, which asks about healthcare utilization (including dental care), costs and patient satisfaction. They found 441 of 26,246 people in the database had bacterial pneumonia (1.68 percent) and that those who never had dental checkups had an 86 percent increased risk of pneumonia compared to those who had twice-yearly appointments.

The body contains 10 times as many microbes (bacteria, fungi and viruses) as human cells on or in the body, from the skin to the gastrontestinal system (including the mouth). Some microbes are good and some are bad, but even bad microbes only cause disease under certain circumstances. In some cases, bacteria can be accidentally inhaled or aspirated into the lungs and cause pneumonia. Bacteria that commonly cause pneumonia include streptococcus, haemophilus, staphylococcus, and anaerobic bacteria. Routine dental visits may reduce the amount of bacteria that can be aspirated, said Dr. Doll.

"Our study provides further evidence that oral health is linked to overall health, and suggests that it's important to incorporate dental care into routine preventive healthcare," said Dr. Doll.

Benefits of laser treatments for dental problems

Researchers have developed computer simulations showing how lasers attack oral bacterial colonies, suggesting that benefits of using lasers in oral debridement include killing bacteria and promoting better dental health.

In a study published in the journal Lasers in Surgery and Medicine, the researchers show the results of simulations depicting various laser wavelengths aimed at virtual bacterial colonies buried in gum tissue. In humans, actual bacterial colonies can cause gingivitis, or gum inflammation. Gingivitis can develop into periodontal disease, which involves a more serious infection that breaks down the bones and tissues that support teeth.

"The paper verifies or validates the use of lasers to kill bacteria and contribute to better health following periodontal treatments," said co-author Lou Reinisch, Ph.D., associate provost for academic affairs at New York Institute of Technology.

Drawing on his background in physics, optics, and calculus, Reinisch, an expert in laser surgery and an associate editor with the journal, created mathematical models based on optical characteristics of gum tissues and bacteria. He then produced simulations of three different types of lasers commonly used in dentistry and their effects on two types of bacterial colonies of various sizes and depths within the gum models.

"One of the questions we asked is how deep could the bacteria be and still be affected by the laser light," said Reinisch. The simulations indicate that 810 nm diode lasers, when set to short pulses and moderate energy levels, can kill bacteria buried 3 mm deep in the soft tissue of the gums. The 1064 nm Nd:YAG laser is also effective with similar penetration depth. Both lasers spare the healthy tissue with the simulations showing minimal heating of the surrounding tissue. Minimizing the thermal damage leads to faster healing, says Reinisch.

"The findings are important because it opens up the possibility of tweaking the wavelength, power, and pulse duration to be the most effective for killing bacteria," Reinisch says. "The doctors will look at this and say, 'I see there is a possible benefit for my patients in using the laser.'"

"The study reveals what's going on in the tissue, so I hope that we're educating the medical professionals by demonstrating that you can do a good job of killing bacteria with certain lasers," says co-author David Harris, Ph.D., director of Bio-Medical Consultants, Inc., which specializes in medical laser product development. "When you do this treatment, you remove an infection and allow tissue to regenerate. Getting rid of the infection means the tissue can heal without interference."

The cost of dental lasers can range from $5,000 to over $100,000, according to Reinisch, and health care professionals require extra training to use them. These costs are passed on to the patient so Reinisch notes there must be a definite benefit for the patient to justify these costs.

Harris noted that the Academy of Laser Dentistry estimates that at least 25% of US dental offices have dental laser capability for periodontal treatment as outlined in the paper, along with a host of other soft tissue surgical procedures and hard tissue procedures like removal of dental decay.

Harris said the video simulations demonstrate what happens when lasers hit buried bacterial colonies.

"This is a great way to present to the doctor esoteric scientific findings in a clinically meaningful format," he said. "The model is a great tool for making predictions of what can happen in the tissue. Our study confirms its use as a way to determine the most effective laser parameters to use clinically."

In a first for the journal, the published results include video depictions of the computer simulations. The journal readers can actually see the soft tissue of the virtual gums and bacteria heat up and cool down as the simulated laser is scanned over the tissue.

The study's methodology of simulating how laser light interacts with tissue has implications beyond dentistry; physicians and surgeons use lasers in various treatments, including vocal cord procedures and dermatological treatments, including those for toenail fungus.

Guided by the results presented in this study, both Reinisch and Harris expect that clinical trials will be designed to validate the findings.

The study, entitled "Selective Photoantisepsis," is published in the October issue of Lasers in Surgery and Medicine.

Dental Sealant Use and Untreated Tooth Decay Among U.S. School-Aged Children

Key Points

• Tooth decay is one of the most common chronic diseases of childhood. If left untreated, tooth decay can have serious consequences including problems with eating, speaking, and learning.

• Two years after placement, dental sealants prevent >80% of cavities in the permanent molars, in which nine in 10 cavities occur. Most children, however, do not have dental sealants, especially children from low-income families. These children are twice as likely as higher-income children to have untreated tooth decay.

• Providing sealants through school-based programs is an effective way to increase sealant use. The benefits of school-based dental sealant programs exceed their cost when they serve children at high risk for tooth decay. The programs become cost-saving after 2 years and save $11.70 per sealed tooth over 4 years.

• In this study, approximately 60% of children aged 6–11 years from low-income families (approximately 6.5 million children), did not have dental sealants. Although sealant prevalence during the last decade increased by 72% among low-income children, these children were still 20% less likely than children from higher-income families to have dental sealants. Children without sealants had almost three times more cavities in permanent first molars compared with children with sealants.

• Providing sealants to the approximately 6.5 million low-income children who currently do not have them would prevent 3.4 million cavities over 4 years.

• Additional information is available at http://www.cdc.gov/vitalsigns.


Abstract

Background: Tooth decay is one of the greatest unmet treatment needs among children. Pain and suffering associated with untreated dental disease can lead to problems with eating, speaking, and learning. School-based dental sealant programs (SBSP) deliver a highly effective intervention to prevent tooth decay in children who might not receive regular dental care. SBSPs benefits exceed their costs when they target children at high risk for tooth decay.

Methods: CDC used data from the National Health and Nutrition Examination Survey (NHANES) 2011–2014 to estimate current prevalences of sealant use and untreated tooth decay among low-income (≤185% of federal poverty level) and higher-income children aged 6–11 years and compared these estimates with 1999–2004 NHANES data. The mean number of decayed and filled first molars (DFFM) was estimated for children with and without sealants. Averted tooth decay resulting from increasing sealant use prevalence was also estimated. All reported differences are significant at p<0 .05.="" br="">
Results: From 1999–2004 to 2011–2014, among low- and higher-income children, sealant use prevalence increased by 16.2 and 8.8 percentage points to 38.7% and 47.8%, respectively. Among low-income children aged 7–11 years, the mean DFFM was almost three times higher among children without sealants (0.82) than among children with sealants. Approximately 6.5 million low-income children could potentially benefit from the delivery of sealants through SBSP.

Conclusions and Implications for Public Health Practice: The prevalence of dental sealant use has increased; however, most children have not received sealants. Increasing sealant use prevalence could substantially reduce untreated decay, associated problems, and dental treatment costs.


Introduction

National data from 1999–2004 indicate that by age 19 years, approximately one in five children have untreated tooth decay (1). Children living in poverty are more than twice as likely to have untreated decay (27%) than are children in families whose income exceeds 200% of the federal poverty level (FPL) (13%). Untreated tooth decay can lead to pain and infection, resulting in problems with eating, speaking, and learning (2). Approximately 16% of children living in poverty were reported by a parent to have had a toothache within the last 6 months (3). A recent multivariate analysis also found that children with poor oral health miss more school days and receive lower grades than children with good oral health (4).

Approximately 90% of tooth decay in permanent teeth occurs in the chewing surfaces of the back teeth (5). Much of this decay could be prevented with the application of dental sealants. Sealants are plastic coatings applied to the pits and fissures in tooth surfaces to prevent decay-causing bacteria and food particles from collecting in these hard-to-clean surfaces. Studies on sealant effectiveness indicate that sealants delivered in clinical or school settings prevent about 81% of decay at 2 years after placement, 50% at 4 years and can continue to be effective for up to 9 years through adolescence (6); no clinically significant adverse effects have been associated with receipt of sealants (6). Sealants are underused, especially among low-income children who have the highest risk for decay. National data from 1999–2004 indicated the prevalence of sealant use among children aged 6–11 years living in poverty was 21% compared with 40% among children from families with incomes >200% of the FPL (1). Increasing sealant use prevalence is a national health goal (7) and the National Quality Forum* has endorsed dental care performance measures aimed at increasing sealant use prevalence in children at elevated risk for tooth decay (8).

School-based sealant programs (SBSP) typically deliver sealants in schools attended by a large number of children participating in the free/reduced-price meal program (i.e., family income ≤185% of the FPL) (6). The Community Preventive Services Task Force† (Task Force) recommends SBSP, on the basis of strong evidence that these programs prevent tooth decay and increase the number of children receiving sealants at schools (6). A second, systematic review of economic evaluations of SBSP conducted for the Task Force found that the benefits of SBSP exceed their cost when they serve children at high risk for tooth decay, becoming cost-saving after 2 years (6) and saving $11.70 per tooth sealed over 4 years (9).

In this report, CDC estimated prevalence of sealant use and untreated tooth decay among low-income (≤185% of FPL, the qualification point for free/reduced-price meal program) and higher-income children aged 6–11 years using data from the recently released 2011–2014 NHANES and compared these data with data from the 1999–2004 NHANES. Estimates of tooth decay averted by providing sealants to children were also calculated.

Methods

To estimate current prevalences of sealant use and untreated decay for U.S. children aged 6–11 years, CDC combined the two most recent cycles of NHANES data (2011–2012 and 2013–2014). NHANES is a multistage probability sample of the noninstitutionalized U.S. population.§ A child was classified as having sealants if at least one permanent tooth was assessed by a dentist to have a sealant present and as having untreated tooth decay if at least one permanent tooth had untreated decay.

Sealant use prevalence is presented for all children aged 6–11 years as well as for the following characteristics: sex; race/ ethnicity; family income ≤185% of FPL versus >185% of FPL; and highest level of education achieved by the head of household. Sealant use and untreated decay prevalence stratified by family income from NHANES 2011–2014 were compared with prevalences from NHANES 1999–2004. Sealant use and untreated decay status were assessed in the same way for both periods (1). Among children aged 7–11 years,¶ the mean number of decayed and filled first molars (DFFM) was estimated for children with and without sealants, by family income status. For each income group, CDC used a published methodology to estimate the number of DFFM that would have occurred over 4 years if a child had not received sealants soon after eruption of the first molars (10). This value was multiplied by the prevented fraction (50%) (6) to estimate averted DFFM per child attributable to sealants over 4 years. Estimates were standardized by year of age to the distribution in the 2000 U.S. Census (1).

Analyses were conducted using statistical software that accounts for the complex sample design of NHANES. Estimates from NHANES were obtained using the examination sample weights. All statistical tests were conducted at a 95% significance level (p<0 .05="" errors="" estimates="" relative="" standard="" with="">0.3 were classified as unstable. To test whether sealant use prevalence varied with the characteristic of the child during 2011–2014, CDC used a chi-square test of independence. A t-test was used to determine whether changes in sealant use and decay prevalences between surveys or mean DFFM by sealant status and income were significant.

Results

Approximately 43% of children aged 6–11 years received at least one dental sealant (Table 1), and sealant use prevalence among low-income children (38.7%) was approximately 9.1 percentage points lower than among higher-income children (47.8%). Sealant use prevalence was highest among non-Hispanic white children (46.0%) and children from households where the head of household had more than a high school education (45.2%) and lowest among non-Hispanic black children (32.2%) and children from households where the head of household had a high school education (37.7%).

From 1999–2004 to 2011–2014, overall prevalence of dental sealant use increased from 31.1%–43.6% (Table 2); increased by 16.2 percentage points to 38.7% (relative increase of 72.0%) among low-income children; and increased by 8.8 percentage points (relative increase of 22.6%) among higher-income children. Untreated decay decreased by 4.9 percentage points to 7.5% among low-income children and remained at about 4% among higher-income children.

Among children aged 7–11 years, the mean DFFM was significantly lower for both higher-income and low-income children with at least one sealant (0.19 and 0.29, respectively) compared with children with no sealants (0.52 and 0.82, respectively) (Table 3). The difference in mean DFFM between children with and without sealants was 0.33 and 0.52 for higher- and low-income children, respectively.

The estimated average annual probability of a permanent first molar developing decay, calculated with DFFM data by year of age for children aged 7–11 years, was 0.07 for low-income children (data not shown). Because of unstable estimates, this probability was not estimated for higher-income children. Over 4 years, sealing all four permanent first molars of low-income children is estimated to prevent 0.52 DFFM per child (Table 4). The NHANES 2011–2014 data set had sealant and income information for 1,371 low-income children aged 6–11 years, representing 10.5 million children nationally. Based on the proportion of low-income children without sealants in the NHANES data set, it is estimated that approximately 6.5 million low-income children currently are not receiving the preventive benefits of dental sealants. Providing sealants to these low-income children would prevent 3.4 million DFFM over 4 years.


Conclusions and Comments

Increasing sealant use prevalence among low-income children could substantially reduce tooth decay. Because the benefits of sealants can last up to 9 years, and untreated decay prevalence is about twice as high for adolescents and young adults aged 12–19 years compared with younger children, it is likely that much of the pain and limitations in eating and learning associated with untreated decay could be prevented by timely application of sealants. In addition, providing sealants to these children could save societal resources. The systematic review of economic evaluations of SBSP conducted for the Task Force found that SBSP became cost-saving within 2 years of placing sealants (6). That review further found that delivering sealants to children at high risk for tooth decay could be cost-saving to Medicaid (9).

Data from the Agency for Healthcare Research and Quality indicate that less than half of children aged 6–11 years from families with incomes <125 2013="" 60="" a="" accessing="" among="" an="" application="" applying="" be="" but="" by="" care="" children="" dental="" effective="" equipment="" few="" found="" fpl="" had="" have="" health="" high-need="" i.e.="" important="" in="" increase="" is="" lack="" licensed="" low-income="" majority="" might="" must="" not="" of="" offer="" one="" oral="" past-year="" placed="" prevalence="" professional="" programs.="" programs="" reason="" regular="" sbsp="" schools="" sealant="" sealants.="" sealants="" state="" states="" strategy="" survey="" that="" the="" their="" therefore="" these="" timely="" to="" visit="" visits="" with="">50% of students participating in free/reduced meal program) (12). Financing is a major barrier to implementing and maintaining SBSP (13). Federal funding of state oral health programs is largely competitive and varies widely by state (13). Many state and local SBSP cover part of their expenses by Medicaid billing (13). Because labor accounts for about two thirds of SBSP costs (6), revenues from Medicaid billing are more likely to cover costs if state policies allow dental hygienists or therapists to assess a child’s need for and to place sealants without a dentist being present. For example, in South Carolina, SBSPs managed and staffed by dental hygienists deliver sealants in approximately 40% of high-need schools (12). These SBSP are primarily financed by Medicaid billing (13).

Another barrier to children receiving sealants in clinical and school settings is low health literacy. A study of California third graders found that their parent’s health literacy and speaking English at home were strong predictors of the child having sealants (14). An Institute of Medicine report on increasing access to dental care among vulnerable and underserved populations also found that low oral health literacy was a major barrier to receiving preventive dental services (15).

The findings in this report are subject to at least one limitation. Because NHANES is not designed to provide estimates by year of age, a large number of estimates of DFFM by year of age and sealant status were unstable. However, among low-income children, all estimates of DFFM used to estimate the annual probability that an unsealed first molar developed decay were stable.

Children with sealants can still be at risk for tooth decay. Whereas fluoride can prevent decay in all teeth, sealants are primarily used to protect the back teeth from decay. Healthy behaviors documented to prevent decay include brushing with fluoride toothpaste and drinking fluoridated water or taking fluoride supplements if drinking water is not optimally fluoridated (2). Many of the studies included in the evidence informing the Task Force’s recommendation for SBSP were conducted among children using fluoride toothpaste in communities with fluoridated water (6), suggesting that sealants provide additional benefit even among children receiving fluoride. Regularly scheduled dental visits are important to deliver preventive services (e.g., topical fluoride) and to monitor and control tooth decay and other oral conditions (2). SBSP can help caregivers of eligible children enroll in public insurance programs (5,6) and can increase utilization of dental care by identifying tooth decay in children who are not regularly seen by a dentist and referring them for needed dental treatment.

New imaging method could enable dentists to detect and heal tooth cavities much earlier

Dental caries-- tooth decay -- is the most prevalent dental disease among children and adults around the world. Left too long before treatment, the disease results in difficulty eating, infection, and even tooth loss. New research published by SPIE, the international society for optics and photonics, in the Journal of Biomedical Optics describes a method enabling much earlier detection using inexpensive long-wavelength infrared imaging.

A cavity begins with a minute amount of mineral loss from the tooth enamel surface, resulting from the acidic environment of dental plaques. If caries can be detected early enough, the progression can be stopped or even reversed.

Dentists currently rely on two methods to detect early caries: x-ray imaging and visual inspection of the tooth surface. But both of these diagnostics have limitations: dentists can't see caries until it is relatively advanced, and x-rays can't detect occlusal early caries -- those on the biting surface of the tooth.

In "First step toward translation of thermophotonic lock-in imaging to dentistry as an early caries detection technology," Ashkan Ojaghi, Artur Parkhimchyk, and Nima Tabatabaei of York University in Toronto describe a low-cost thermophotonic lock-in imaging (TPLI) imaging tool that would allow dentists to detect developing caries much earlier than x-rays or visual analysis.

The TPLI tool uses a long-wavelength infrared camera to detect the small amount of thermal infrared radiation emitted from dental caries after stimulation by a light source.

To test the effectiveness of this new imaging tool, the authors artificially induced early demineralization on an extracted human molar by submerging it in an acid solution for 2, 4, 6, 8, and 10 days. The TPLI image taken after just 2 days clearly showed the presence of a lesion, whereas a trained dental practitioner could not visually detect the same lesion even after 10 days of demineralization.

Journal associate editor Andreas Mandelis, professor of mechanical and industrial engineering at the University of Toronto, said, "This paper will have a high impact on the way dentists diagnose incipient caries. The longwave IR thermophotonic imaging technology is at its nascent steps, but this paper brings it closer to actual clinical practice."

The tool has the benefits of being noncontact, noninvasive, and low-cost, and has great potential as a commercially viable diagnostic imaging device for dentistry.

Immediate dental implant placements using osteotome technique

Immediate implant placement using the osteotome technique is a gentle technique and offers several significant advantages over the traditional graded series of drills:

1.    This technique retains the total bone mass which is necessary to preserve the remaining bone and improve its quality, mainly, when the alveolar bone is compromised in quality or quantity.
2.    It is an alternative to block grafting in select cases to increase the ridge width for implant placement.
3.    It allows immediate placement of implants in narrow ridges at the time of expansion.
4.    Osteotomes take advantage of the fact that bone is viscoelastic and can be compressed and manipulated. Compression creates a denser bony interface with increased bone to implant contact and therefore good initial stabilization of the dental implant.
5.    Heat is a major detriment to osseointegration, but the osteotome technique is an essentially heatless and therefore should not destroy the viable bone-forming cells.
6.    This technique also allows for greater tactile sensitivity.
7.    It is minimally invasive and cost effective.
8.    Faster prosthetic restoration is possible.

In spite of this Straumann dental implants with an SLA endosseous surface offer a promising solution for rapid anchoring in the bone and the bone-to-implant contact is found to be higher on rougher surfaces than on smoother interfaces with high percentage contact in descriptive histomorphometric studies and high removal torque values in functional studies. This procedure for a better and faster bone integration of SLA implants in the initial healing period which is optimized mechanically and topographically.


The research has been published in The Open Dentistry Journal, Volume 10, 2016.