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Assessing Implant Torque Device Reliability

Does Steam Sterilization affect Accuracy of Spring- style Implant Torque Devices?

When accounting for complications over a 5 year span, Mashid et al reported that “screw loosening has been stated as the most common complication in implant” dentistry. One leading cause could be torque driver reliability.

Torque drivers include “toggle-type or friction-style,” and “beam-type or spring-style.” Many believe spring-style offer more accuracy even though accuracy becomes suspect after steam sterilization. To test the effects of steam sterilization, Mashid’s team tested 5 each from Nobel Biocare, Straumann [ITI, photo at top], and Biomet 3i [3i]). The “peak torque” of each was measured before and after steam sterilization.

Materials and Methods

All devices were tested ten times at 35 Ncm prior to steam sterilization. Sterilization of each was managed according to manufacturer directions: “Nobel Biocare devices should be dismantled for disinfection, cleaning and drying and then the parts should be assembled before sterilization. In the ITI group, dismantling of devices is proposed. Each component should be disinfected, cleaned, and dried, but sterilized separately. For 3i samples, dismantling of the device is not proposed and disinfection of the outer surface is the only protocol to be considered.” The recommended protocols and sterilizations were repeated 100 times at 134°C for 18 min, and then measured 10 times for torque accuracy.

Results

Before steam sterilization, all the tested devices stayed within 10% of their targeted torque values. After 100 sterilization cycles, there were no significant difference in the Nobel Biocare and ITI devices. There was, however, an increase of error values in the 3i group, which showed more than a 10% difference with a maximum difference of 14% in 17% of torque measurements. The authors also reported that 3i torque devices had developed “corrosion of the spring in the handle” that may have contributed to its inaccuracy.

Different research by Santos et al, tested Biomet 3i, Nobel Biocare, Straumann, and Conexao at 20 Ncm and reported 62.5% were within 10% of the tested value. However, when tested at a 32 Ncm target, “only 33.3% of all values from each manufacturer were considered accurate,” with ITI being the most consistent in accuracy for both values. During the Santos testing, each torque device had been in clinical use for less than 2 years. With the amount of use and “sterilization protocols” unknown, their findings might better reflect the real world of clinical dentistry than would a highly controlled, laboratory testing protocol. The reports reinforce the need for manufacturer recalibration with frequency matched to use.

implant screws

Preventing Implant Screw Loosening

Screw Loosening, a Frequent Problem?

Implant screw loosening is a major concern for both dentists and dental technicians. Unfortunately, the literature indicates it is a frequent problem, with loosening rates as high as 12.5%. Today, there are new ways to decrease its frequency.

Forces keeping screws tight include the “friction between the threads, between the head of the screw and the abutment, and between the implant and the abutment. The force that clamps two screw-tightened components together is called the preload and it depends on the composition of the materials, the texture of their surface and their degree of lubrication.”

Some screws have special surface treatments that “reduce the friction coefficient” and increase the preload to keep screws tighter, longer. One example is TorqTite® (Nobel Biocare Holding AG, Balsberg, Kloten, Switzerland), which uses a “diamond-like, carbon” lubricant.

Using the two types of screws described above, Saliba et al, tested the amount of torque required for screw removal that would simulate how and why an entire implant system would loosen, clinically.

Materials and Methods

Testing was performed on 20 Neodent titanium implants (Osteointegráveis, Curitiba, Paraná, Brazil), with 4.1 platforms, similar to the original Branemark design. Their hexagon bases were removed so abutments could be “rotated on the implant platform during the loosening of the fixation screw.”

Ten relied on an abutment held to the implant with non treated M2.0 titanium screws (Neodent). A different set of ten screws were covered with TorqTite® (Nobel Biocare). “The abutment was attached with a screw, first using a hexagonal 1.2 mm digital wrench (Neodent), followed by tightening with a prosthetic ratchet torque wrench (Neodent) to a torque of 32 Ncm.” Then, the screws were unthreaded to record the highest torque values “required to completely loosen the abutment.”

Results

Titanium screws covered with solid lubricants performed better than plain titanium screws in maintaining the prosthetic implant-abutment junction. The results showed that their unscrewing torque value was higher than the torque applied during seating.

Implant screw chart

Which Screw to Use

Which type of screw, titanium or gold, is another variable worth exploring. In trying to better address loosening, Farina, et al compared gold and titanium screws. Testing for loosening values after simulated mastication included 20 dentures with eight different groups representing passive and vertical misfits with gold or titanium screws. Their results were based on “(1) 6 months of use, torque loosening, re tightening, another 6 months of use, and loosening torque; and (2) 1 year of use followed by loosening torque.”

Their research findings concluded, “After 6 months and another 6 months of clinical use simulation, titanium screws showed higher loosening torque values than did gold screws for the same fit level (P <.05). After 1 year of clinical use simulation, titanium and gold screws in passively fit dentures showed higher loosening torque values than they did in misfit dentures (P <.05). The titanium screws presented a decrease in the loosening torque after 1 year in misfit dentures.”

Above chart and image at top of page:

Biomechanical considerations for the screw of implant prosthesis: A literature review; J Korean Acad Prosthodont. 2010 Jan;48(1):61-68. Korean; Authors, So-Min Im, et al

hand in dominoes

Private Practitioners Raising the Competitive Bar, Changing the Trends

National Public Relations Campaign Underway

Thousands of consumers are selecting a new dentist each day. Because they can’t measure quality, their decisions are based on hopeful trust. Because consumers are often drawn to brands, private practices with weak brand presence are losing patients to large regional brands, representing more than $100,000 in lost revenues, annual . In response, a public relations campaign is being launched to help private practices compete more effectively.

Developing the Consumer Message

The first ever, Private Practice, national public relations strategy session took place on November 12, at the corporate headquarters of Braithwaite Communications. The three hour meeting, sponsored by OPT-In Dental Advantage, identified consumer concerns, why they exist, dental industry strengths and weaknesses, and storylines to be used. At the start, efforts were made to keep all messages positive. However, after sharing their own negative dental experiences, the Braithwaite team decided that too many bad things are happening too often, and that consumers need to be made aware of not just what to look for, but also, what to avoid. The discussion topics included potential advantages and disadvantages of different practice models and philosophies, insurance transgressions and competitive opportunities, and new structures to promote OPT-In member labs’ and dentists’ strengths over competitors’ weaknesses.

An Industry-wide Challenge

By the end of the meeting, enough storylines had been identified to keep the public relations campaign rolling for several months. In the meantime, OPT-In Dental Advantage members have received financial support from manufacturers, distributors. OPT-In dental laboratory members are playing a key role,  and are also earning manufacturer support, with many seeking ways to address the same problems. Dental laboratory owners are essentially in the same boat, in that, what happens to private practitioners happens to dental labs. Currently, OPT-In laboratory members, listed here, are the only dental laboratories investing in their private practice customers.

Storytelling, an Important Advantage

Braithwaite will be weaving stories for release through major news outlets that will help consumers understand the importance of seeking dental care in trustworthy settings. The importance of storytelling was highlighted in an article published in the Harvard Business Review, online. In the article, Keith Quesenberry, a researcher at Johns Hopkins, states, “People are attracted to stories because we’re social creatures and we relate to other people.” The article also points out, stories can open doors to emotional decisions that are closed to cold facts. We can use “data” to influence thought, “but it doesn’t inspire them to act; to do that, you need to wrap your vision in a story that fires the imagination and stirs the soul,” states author, Harrison Monarth. The team at Braithwaite will be providing this expertise through national outlets such as, The Wall Street Journal, New York Times, Washington Post, etc.

An Industry Working Together

Time is of the essence. With the number of non Medicaid dental patients remaining flat, revenues lost to competitors, and patient loyalty, are difficult, even impossible to regain. Additionally, patients need to be educated about the real cost of insurance company tactics to deny care and benefits. Addressing these issues, the OPT-In national public relations campaign is being launched because enough dentists and lab owners made it possible. Through broader cooperation, manufacturers, distributors, dental technicians, and dentists could accomplish even more, faster.

For more information, visit our website, OPT-In Companies, or call, 855-321-OPTN (6786).