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JADA Specialty Scan - Prosthodontics
Prosthodontics - A Quarterly Newsletter on Dental SpecialtiesJADA Specialty Scan

Improving obstructive sleep apnea treatment

A 2-stage technique for fabricating a custom face mask for patients needing continuous positive airway pressure therapy (CPAP) was presented in the May issue of Journal of Prosthetic Dentistry.

According to the authors, the method eliminates frequent problems that single-stage impressions create, including voids, compressed tissue, inadequate borders, and rushed setting times. “On the basis of our extensive experience, irreversible hydrocolloid and [polyvinyl siloxane] face impressions account for about 20% of remakes,” the authors said in the discussion. “These issues are eliminated with this 2-stage technique. Syringing the first stage directly to the face provides control of all these issues.”

Also in the discussion, the authors said an additional strength of the technique outlined in the article is that it allows more time to create the impression so that patients’ facial muscles remain more relaxed. It is a critical factor authors said, as the seal of the mask is dependent on its accuracy and a relaxed state best represents the face during sleep.

Authors reported that the technique not only reduces the time required for the impression and the delivery of the mask but also provides a superior CPAP interface. Evidence shows that most patients discontinue CPAP therapy because of mask leakage.

Read the original article.

Photo courtesy of The Journal of Prosthetic Dentistry.


Consulting Editor: Donald A. Curtis, DMD, FACP
Diplomate, American Board of Prosthodontics
Professor, University of California San Francisco

Guidance on tooth- and implant-borne restorations

In clinical practice guidelines (CPGs) published in two distinct tables for tooth- and implant-borne restorations—categorized according to type of restoration and by patient recall, professional maintenance, and at-home maintenance—were published in the January issues of The Journal of the American Dental Association and the Journal of Prosthodontics.

The document is the result of a systematic review conducted by a team of scientists to address a need for direction for general dentists, prosthodontists, other dental specialists, dental hygienists, allied health personnel, nurses, social workers, students, patients, medical and dental insurance carriers, and public health departments.  The goal was improved clinical outcomes for patients.

Although empirically used CPGs have long been used in medicine, scientists conducting the research said that modern CPGs involve a systematic and transparent process for scrutinizing scientific evidence, and recommendations are made with the intent that they will be updated and modified as scientific evidence becomes available. The authors found guidelines for both tooth-borne and implant-borne restorations lacking. For example, they found limited guidance on the options and relative merits for professional and at-home maintenance protocols to predictably achieve stable results in tooth-borne restorations. Guidelines for the maintenance of implant-borne restorations were poorly defined and often based on empiricism or traditional protocols for patients with natural dentition rather than on maintenance of implant-borne restorations and supporting tissues.

To develop the guidelines, scientists conducted two separate systematic reviews of the literature to evaluate the recall and maintenance regimens for tooth- and implant-borne restorations. For tooth-borne restorations, 16 studies, 9 of which were randomized controlled clinical trials (RCTs), were identified in the systematic review that reported data regarding a combined 3,569 patients. For implant-borne restorations, 20 studies, 11 of which were RCTs, were identified that reported on 1,088 patients. The team of scientists, made up of a panel of experts appointed by the American College of Prosthodontists, American Dental Association, Academy of General Dentistry, and American Dental Hygienists Association scrutinized, tabulated, and analyzed the data to formulate conclusions and create the CPGs. The major outcomes and consequences considered during formulation of the CPGs was risk for failure.

Potential benefits that authors considered regarding these guidelines included improved oral health and longevity of natural teeth, tooth-borne and implant-borne restorations and improved oral health-related quality of life. “This baseline document is intended to improve patient care protocols, but is not intended as a standard of care,” the authors reported. “The outlined CPGs should be supplemented with professional judgment and consideration of the unique needs and preferences of each patient.”

In the article summary, they said, “The various guidelines were made using the best level of evidence whenever available. Guidelines made using expert opinion and consensus included the best possible analysis of best clinical practices, clinical feasibility, and risk-benefit ratio for patients.”

Read the original article.


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3M Oral Care has updated its Impression Troubleshooting 
Guide, an interactive digital tool allowing dentists to quickly find answers to 12 of the most common issues in the impression taking procedure. With the newly optimized online guide, dentists can feel confident throughout the impression taking process, helping to ensure accurate outcomes each and every time.


Implant replacement in failed sites

Increasing the predictability of second and third implant replacements was the aim of a team of scientists who conducted a review of the literature and published their findings in the May issue of The International Journal of Oral & Maxillofacial Implants.

Determining factors causing implant failures at second and third attempts was central to the research, which sought to answer the question “Do patients undergoing implant replacement (second and third attempts) in previous failed sites have comparable clinical outcomes by means of implant survival/failure rate to implants placed at the first attempt?”

To explore, the team conducted an electronic search of the English-language literature to November 2014 for studies investigating dental implants placed in previously failed sites of at least 10 patients who were followed for 12 or more months. All studies included clinical outcomes at first, second, or third attempts and used root form or cylindrical titanium implants with machined or modified surfaces.

Of 7 studies ultimately accepted for inclusion, 5 were retrospective studies, and 2 were case series. Study design, number of patients, number of implants, removal time, survival rate at second and third replacement, interval between retrieval and replacement, and follow-up were among the data extracted and analyzed by scientists.

From a total of 396 patients, 470 implants were inserted to replace previously failed ones, in which 31 implants were placed in sites where previous implants had failed twice. Survival rate of the second implantation attempts showed an overall mean survival rate of 88.84 % with a follow-up period (standard deviation) of 41.59 (16.77) months. Studies mentioning third implantation attempts showed a large deviation in survival rate. In total, 8 of 31 implants failed, resulting in an overall mean survival rate of 74.2% at the follow-up (standard deviation) of 29.66 (14.71) months.

Most of first implantation failures were due to biological reasons, such as peri-implantitis, manifesting mobility, failure of osseointegration, inflammation and suppuration, infection, prolonged acute pain, and overload.

Five studies provided comparative data about the time interval between failed implant retrieval and the placement of implants at the second attempt. The time interval was expressed in months and ranged from 0 to 49 months. No significant differences in outcomes were observed between the immediate and delayed implantation groups. 

A total of 159 of 350 sites/implants with inadequate bone volume underwent additional bone augmentation procedures during the second implantation for a mean bone augmentation rate of 45.43%. Two of the studies indicated that after site augmentation, implant survival was not associated with greater failure compared with implants that were placed in healthy bone.

There was no difference in the failure rate between implant replacement in the maxilla and mandible or in failure rates between anterior or posterior sites.

In the discussion, the authors noted that recent studies showed no significant difference in the failure rate of the second reimplantation attempt between immediate and delayed replacement groups. They said that several studies reported immediate implant replacement with a wider diameter in the same socket, and that these studies suggested that a 1-year healing period might not be necessary.

Also in the discussion, the authors noted that immediate replacement has several advantages, including minimizing future bone resorption.

“Furthermore, the immediate implantation in these cases represents an immediate solution to a clinical complication and noticeably reduces the length of treatment and the number of surgical procedures,” the authors noted from previous research. They surmised that there was still a lack of literature showing the 3-dimensional changes for immediate versus delayed implant replacement.

Also in the discussion, the authors said the major reported predictors for implant success are generally divided into 3 areas: patient-related factors, prosthesis characteristics, and site characteristics. Among patient-related factors, although a multitude of studies reported a significantly lower initial survival rate and further loss of implants if the patients were smokers, in the studies on reimplantation, smokers were reported to exhibit a similar survival rate in a second or third attempt as did nonsmokers.

Among results regarding implant and prosthesis characteristics, a better implant surface meant faster bone apposition. That characteristic may offer a better prognosis when failed implants have to be replaced at the same site, and it coincides with other research showing that implants with smooth surfaces failed at earlier stages than did implants with roughened surfaces.
Among site characteristics, the scientists’ analysis of risk factors indicated that the survival rates of replaced dental implants might be increased by retrieving the initial failed implants by means of meticulous removal of granulation tissue of the failure site together with the use of wider implants with improved (treated) surfaces. In an attempt to maintain the integrity of bone walls, implant extraction should be performed as gently as possible, the authors said. In addition, the success of reimplantation might be increased by using various bone-grafting techniques or additional implants when necessary.

Overall, the authors said there was still a lack of sufficient evidence-based data regarding implantation in previously failed sites and called for further clinical studies with more extensive clinical cases and longer follow-up periods. However, they concluded that implant replacement is a reasonably feasible option for early and late implant failure if modifiable risk factors are controlled for before proceeding.

Read the original article.

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ADA brochure helps patients close the gap

Patients with a missing tooth are aware of how it looks, but they may be less aware about the dental effects. The ADA’s brochure Your Single Tooth Implant reviews the reasons to replace a missing tooth, describes the benefits of implants, and reviews who is a good candidate.

The brochure reinforces the message that nothing comes closer to replacing a natural tooth than a dental implant. An illustration shows the structure of a single-tooth implant, so patients can picture the process. The 6-panel brochure is sold in packs of 50; a personalized version is also available. To order, call 1-800-947-4746 or go to Readers who use the code 16403E before July 8 can save 15 percent on all ADA Catalog products.


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What is Specialty Scan?

This is one in a series of quarterly newsletters updating dentists on selected specialties in dentistry. Information presented is aggregated and summarized from previously published materials, each item attributed to its publication of origin. This issue of JADA Specialty Scan focuses on prosthodontics, the second in the series on this topic for 2016. Other Specialty Scan issues are devoted to endodontics, orthodontics, oral pathology, oral and maxillofacial radiology and periodontics. The ADA has engaged the specialty organizations in these areas as well as its own Science Institute and Division of Legal Affairs to assist with these newsletters. We welcome your feedback on this and all Specialty Scan issues.

Editorial and Advertising Policies

Any statements of opinion or fact are those of the authors and do not necessarily reflect the views of the American Dental Association. Neither the ADA nor any of its subsidiaries have any financial interest in any products mentioned in this publication. Any reference to a product or service, whether in advertisements or otherwise, is not intended as an endorsement or as approval by the ADA or any of its affiliated organizations unless accompanied by an authorized statement that such approval or endorsement has been granted.

All matters pertaining to advertising should be addressed to the advertising sales manager, Sales and Marketing Department, American Dental Association, Publishing Division, 211 E. Chicago Ave., Chicago, IL, 60611, 1-312-440-2740, fax 1-312-440-2550. All advertising appearing in ADA publications must comply with official published standards of the American Dental Association, a copy of which is available on request.