Prosthodontics - A Quarterly Newsletter on Dental SpecialtiesJADA Specialty Scan

Reducing bone loss after extractions

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Socket grafting not only limited the amount of bone resorption, but appeared to compensate for alveolar contraction independent of buccal bone thickness, scientists publishing in the March/April issue of The International Journal of Periodontics & Restorative Dentistry found.

An extensive body of evidence points to rapid alveolar bone loss during the first three to six months following tooth extraction and gradual reduction in dimensions thereafter. Such shrinkage of the hard and soft tissues complicates implant positioning and leads to unpredictable esthetic outcomes.

Researchers in Italy found that the dental literature didn’t explain the reasons for a wide range of variability in horizontal bone width healing,  nor did it consider the effects of buccal plate thickness. Thus, they undertook their own research. 
        
Their goals were twofold:

To investigate, scientists used a flapless procedure to extract 48 teeth from 41 patients – 16 premolars and 32 molars. The alveoli of the test group patients were filled with a bovine bone mineral blended with collagen and covered with a porcine collagen membrane. Bovine bone mineral is the material most frequently reported in the literature for post-extractive socket grafts. The sutures were removed after 14 days. The control group received no additional treatment after extraction, and no sutures were placed.

Researchers followed the patients postoperatively at two and four weeks and at two and four months, when patients were scheduled for dental implants at the extraction sites. The horizontal width of the alveolar ridge and the vertical ridge height were measured at baseline and four months. They measured the thickness of the buccal bone after teeth were extracted.

Four months after tooth extraction, the test group (grafted sockets), showed a minimal loss of horizontal bone width (7.23 percent) compared with the loss displayed by the control group (spontaneous healing) (40.15 peercent). The vertical ridge change was also minimal in the test group (0.56 millimeters) and more pronounced in the control group (1.58 mm), a statistically significant difference, “suggesting that soft tissue contour changes are related to alveolar bone ridge remodeling,” authors reported.

Results also showed no correlation between the initial thickness of the buccal bone and the alveolar bone at four months in the test group, while a strong negative correlation was found between the initial thickness of the buccal bone and alveolar bone loss in the control group at four months.
Researchers deduced that leaving the extraction socket to heal naturally may result in alveolar bone loss.

“In the ridge preservation sites, no correlation was found between the initial buccal bone plate dimension and the alveolar bone loss, which suggests that socket grafting appears to compensate for alveolar contraction independently from buccal bone thickness,” authors reported. “In the control group, a thinner buccal bone plate was correlated with greater alveolar bone loss.”

http://www.ncbi.nlm.nih.gov/pubmed/24600657

 

Consulting Editor: Lars O. Bouma, DDS
Diplomate,
American Board of Prosthodontics


Beauty and the creation of prosthetic teeth

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What is important when creating materials that mimic natural objects, such as prosthetic teeth? Researchers investigating shape and esthetics published a report in the June 2014 issue of the Journal of Prosthetic Dentistry. It describes the nature of compound complex curves, their historical context and their importance in creating natural-looking prostheses.

“Complex suggests an unavoidable and necessary lack of simplicity but does not imply a fault or failure in design or arrangement,” authors advised. They cited examples of natural compound complex curves, such as the spiral of a nautilus shell, the edge of a tree leaf, ripples in sand on a seashore, mamelons on an incisor tooth and the fine texture of perikymata on surface enamel.

Reproduced in early cave art and rock carvings by people with sophisticated mathematical knowledge, compound complex curves have long been used in art as a means of creating interesting surfaces.

Authors said that although natural form may appear simple, it rarely is, and an understanding of the compound complex curves found everywhere in nature is necessary for authenticity. “An artificial dental prosthesis must appear authentic to the observer,” they noted.

The research delves deeply into the history of the mathematical description of beauty, its use by current artists and architects, as well as in prosthodontics as a guideline for setting anterior teeth.

 Authors said the two classic approaches to defining an attractive object or shape – qualitative and quantitative – have merged with the advent of modern computers, graphic interfaces and design, and computer-aided design and computer aided manufacturing (CAD/CAM).

“Accuracy and detail demand high computational power,” authors said, pointing to previous research. “Generic forms are stretched to fit the prosthetic tooth being created, but if they are simply stretched in a linear manner, the compound complex curves will lose their authenticity. This may not have much functional impact but will diminish their intrinsic beauty.”

http://www.ncbi.nlm.nih.gov/pubmed/24589121

 
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BioTemps Provisionals
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Medications for dental surgeries

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Critical summaries published in the September and October 2014 issues of The Journal of the American Dental Association assess the evidence of drug safety and efficacy for major clinical challenges: post-operative pain and dental implant failure due to bacterial infection.

The September article http://jada.highwire.org/content/145/9.toc  evaluates research on the therapeutic superiority of combining acetaminophen and a nonsteroidal anti-inflammatory (NSAID) for post-operative pain.

The authors observed that a review of many double-blinded, controlled clinical trials noted the value of combining ibuprofen with acetaminophen compared to pain relief with either acetaminophen or an NSAID alone.

The October article http://jada.highwire.org/content/145/10.toc explores research questioning the value of prophylactic antibiotics in reducing implant and prosthetic failure.

“There is growing evidence suggesting that, in general, starting systemic antibiotic administration at the time of implant placement significantly reduces the rate of osseointegration failure in the short term,” authors observed.

AAOMS publishes 2014 position paper on MRONJ

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The 2014 update to the American Association of Oral and Maxillofacial Surgeons’ (AAOMS) position paper on medication-related osteonecrosis of the jaw was published in the October 2014 issue of the Journal of Oral and Maxillofacial Surgery.

“The knowledge base and experience in addressing MRONJ has expanded, necessitating modifications and refinements to the previous position paper,” authors reported. The update contains revisions to diagnosis, staging and management strategies and highlights current research. It begins with a suggestion to change the terminology from bisphosphonate-related osteonecrosis of the jaw (BRONJ) to medication-related osteonecrosis of the jaw (MRONJ).

“The change is justified to accommodate the growing number of osteonecrosis cases involving the maxilla and mandible associated with other antiresorptive (denosumab) and antiangiogenic therapies,” authors explained.

The updated position paper was created to provide:

The research recognizes data from studies published since 2009, when the AAOMS published its previous position paper on the subject. It includes sections on risk factors, management, staging and treatment strategies for patients in various groups. For example, since the publication of the 2009 guidelines, successful treatment outcomes for all stages of MRONJ after operative and nonoperative therapy have been reported.

“Except for the more advanced cases of stage 3 disease or in those cases with a well-defined sequestrum, it appears that a more prudent approach would be to consider operative therapies when nonoperative strategies have failed.”

A stage 0 category was added in 2009 to include patients with nonspecific symptoms or clinical and radiographic abnormalities that might be due to exposure to an antiresorptive agent.

“At that time, the risk of a patient with stage 0 disease advancing to a higher disease stage was unknown,” the paper states. “Since then, several case studies have reported that up to 50 percent of patients with stage 0 have progressed to stage 1, 2 or 3. Therefore, stage 0 seems to be a valid disease category that captures patients with prodromal disease (unexposed variant).”

The paper reported that the AAOMS considers it vitally important that the information in the update be disseminated to other relevant health care professionals and organizations.

http://www.joms.org/issue/S0278-2391(14)X0009-1

 

ADA offers discount on mini-implant brochure

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Now through Nov. 30, the ADA is offering members free shipping on all patient education brochures with a minimum order of $75.

Members can order “Mini Dental Implants” (W419) through the ADA Catalog and receive free shipping with a minimum $75 order using promo code 14369E.  The six-panel brochure is available in packets of 50 for $26; retail price $39. Discounts also are available in higher quantities.
Written for the dental patient, the brochure conveys essential facts about when mini-implants are a viable option for your patient. It also highlights the restorative benefits of implants, explains placement steps and says who is a candidate. The brochure includes photos of mini-implant posts and overdentures.

 Members can preview this and other ADA brochures online at adacatalog.org. Orders can be placed online or by calling the ADA Member Service Center at 1-800-947-4746. Remember to use the promo code 14369E to get free shipping with a minimum $75 order.  

 
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Inclusive Tooth Replacement System
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Clinical tip: Implant placement in the esthetic zone

By Siamak Abai, DDS, MMedSc

A surgical approach combining restorative-driven treatment planning with evaluation of anatomical characteristics can be used confidently to address the challenge of implant placement in the esthetic zone. Advancements in diagnostic tools, implant site preparation, and the CAD/CAM technology used to produce custom restorative components offer clinicians a predictable path to success.

Determining the correct labio-lingual orientation requires working within the available bone and accommodating the planned restoration to the maximum degree possible. Mesial-distal positioning of an anterior implant involves careful evaluation of the underlying anatomy and the soft tissue surrounding the implant site as well as a variety of measurements.

By fully considering the position of the final prosthesis prior to and during implant placement, a restoration can be achieved that is reasonably supported by the implant and the surrounding bone, mimicking the appearance of a natural tooth. Custom healing components help to maintain a restorative-driven approach by contouring the soft tissue in order to preserve the gingival architecture and interdental papillae surrounding the implant site.

Where indicated, immediate provisionalization of anterior implant cases can help facilitate patient acceptance of the final restoration. Provided that there is adequate primary stability, a custom temporary abutment and provisional can help optimize the peri-implant soft tissue and margins to achieve an esthetic emergence profile.

Figures 1, 2: The patient presented with an edentulous site in the area of tooth #9. A treatment plan employing a screw-retained temporary crown was selected in order to contour the soft tissue during healing.

Figures 3, 4: Implant placement and delivery of screw-retained temporary crown.

Figures 5, 6: The final restoration exhibited an esthetic emergence profile resulting from restorative-driven implant placement and months of tissue contouring provided by the screw-retained temporary crown.

While anterior implant cases are among the most difficult to restore, clinicians can achieve a predictable result by thoroughly evaluating patient anatomy and following a clear set of clinical guidelines. Utilizing the available diagnostic tools and restorative-driven treatment planning, implants can be placed in a manner that optimizes the final prosthetic outcome and meets the esthetic demands of our patients.

To read the full article, visit www.inclusivemagazine.com

 

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 fourth in the series on this topic for 2014. Other Specialty Scan issues are devoted to endodontics, orthodontics, oral and maxillofacial radiology and periodontics. The ADA has engaged the specialty organizations in these areas as well as its own divisions of Science and Legal to assist with these newsletters. We welcome your feedback on this and all Specialty Scan issues.

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