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

Implant healing abutment cleaning, reuse

A preliminary study regarding reusing implant healing abutments (HAs) confirmed the ineffectiveness of conventional decontamination and found that a compared procedure, using a device, efficiently and vastly cleaned HAs’ surfaces. However, the researchers called for further studies to investigate the chemical composition and clinical influence of biological remnants before considering reuse of HAs. They reported these findings in March/April issue of The International Journal of Prosthodontics. Economic considerations often lead dentists to questionably reuse implant HAs, although they are indicated for single use. Reuse involves a sterilization procedure. Despite sterilization strictness, this step in the titanium clinical management protocol appears to be incomplete, researchers say.

Researchers worked from the null hypothesis that no difference in cleaning efficacy exists between conventional cleaning and decontamination and a recently proposed 3-step approach to automatically clean and decontaminate HAs.

The novel 3-step approach involves automatically cleaning and decontaminating HAs using ultrasonic soaking, tumbling by rotating metal pins, and ion pasteurization.

To test their hypothesis, researchers retrieved 66 HAs from 33 participants for quantitative analysis. They used 9 HAs—3 from each of 2 groups (control and test) and 3 brand new ones. They collected 2 HAs from each participant after at least 1 month of clinical use to obtain identical HAs with similar oral environmental conditions.

Their methodology entailed mechanically wiping the HAs in the control group with disinfectant sponges and then putting them in an ultrasonic bath for 30 minutes. They treated the HAs in the test group using an automatic cleaning system. Finally, they separately packaged the HAs and sterilized them for 20 minutes at 134°C.

The researchers divided each HA into 15 predefined areas and applied a protein-specific stain (phloxine B 1.5% weight by weight). They applied quantitative analyses using a light stereomicroscope at X10 magnification and 2 calibrated examiners. They placed the HAs in a 24-well plate with 1 milliliter of fibroblast 3T3 cell suspension.

After 48 hours, they fixed and dehydrated the specimens and then sputtered them with gold for scanning electron microscope analysis. For analysis, researchers applied the Kolmogorov-Smirnov test to assess data normality and χ2 and Mann-Whitney tests for descriptive analysis. They performed post hoc analysis to evaluate statistical power. Level of statistical significance was preset at α = .05.

The researchers’ results showed proteic contamination in 11 of the 30 test group HAs and in all 30 of the control HAs, reflecting a significant difference statistically between the 2 groups. “Contaminated areas were observed with different frequencies in the 2 groups (3.6% test; 78.2% control; P < .001),” the researchers wrote. “In vitro assay showed a uniform cell distribution in test HAs, while areas of debris without adhering cells were a common finding in the control HAs.”

The researchers found that, while their growth was regular and their distribution uniform on clean surfaces of both new and used components, fibroblasts failed to colonize contaminated areas of HAs. “The analyses performed in this study confirmed previously published data on the ineffectiveness of conventional procedures in decontaminating used HAs, while the tested device resulted in efficiently cleaning more than 95% of the evaluated surfaces,” researchers wrote.

However, they described limitations in their preliminary study, including use of a convenience sample size, examination of only 1 type of HA, and lack of precise identification of the proteic contaminants or evaluation of their role in tissue healing.

Read the original article here.

 

Consulting Editor:
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Screw-retrievable, cement-retained implant guideline

An article in the November/December 2017 issue of The International Journal of Prosthodontics examines possible advantages achievable when combining the primary benefits of cement-retained implant-supported fixed partial dentures (ISFPDs) with those of screw-retained ISFPDs.

The research team comprised Saudi Arabian and American dental investigators. They noted in their study that, separately, cement-retained and screw-retained ISFPDs have different advantages and drawbacks. Cement-retained ISFPDs grew in popularity over the last 2 decades on reports of favorable stress distribution, but the cementation process is inherently risky. Screw-retained ISFPD designs offer easy prosthesis retrievability but more mechanical strains.

Regardless of whether retention is attained via screws or cement, ISFPD longevity may be associated with clinical complications, the researchers wrote.

In their study, they discuss the desirable attributes of these traditional approaches to ISFPD retention and proffer a prosthetic guideline discussing the parameters of design and fabrication principles of combined advantages in the form of screw-retrievable, cement-retained (SRCR) ISFPD.

“The SRCR ISFPD is defined as an ISFPD that includes a cement-retained fixed partial denture (FPD) superstructure with screw access channels designed to correspond to the screw access channels of the custom abutments to which it is cemented,” the researchers wrote.

Before divulging fabrication steps and their guideline, the researchers provided diagnosis and decision-making advice for determining the type of ISFPD to be used. This advice covers an impression making stage, custom abutments trial placement stage, and a definitive cast stage. “Proper diagnosis of ISFPD type based on the diagnostic and prosthetic classifications for ISFPD is critical,” they wrote.

They report using tactile resistance as an objective diagnostic assessment to decide the type of ISFPD indicated.

Researchers concluded that, when clinically applicable, SRCR ISFPDs uniquely offer the combined advantages of traditional retention approaches—easy retrievability and less stress or strain supporting implants or prosthetic components and a superior long-term seal to the cement retention mechanism in partially edentulous patients.

Read the original article here.

 
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Shortened dental arch outcomes

In a 10-year randomized controlled clinical trial of the shortened dental arch (SDA), German researchers compared the outcome of replacing molars with a partial removable dental prosthesis (PRDP) to that of not replacing the molars according to the SDA concept. They published their study results in the January/February issue of The International Journal of Prosthodontics.

The researchers hypothesized that the 2 different nonimplant treatments in the bilateral SDA would lead to different outcomes. They noted the existence of previously published similar studies on 3-, 5-, and 8-year results in which, basically, there were no relevant differences between the treatments. They declared that their analysis is the first to present 10-year results for the primary outcome tooth loss.

In the ongoing multicenter trial, eligible patients were older than 35 years and missing all molars in 1 arch—the study arch—and had at least the canine and 1 premolar present on each side. Of 215 enrolled patients, 152 received study treatment, and 82 reached the 10-year examination.

Researchers kept all patients who received the study treatment and examined them further regardless of the occurrence of primary outcome—tooth loss. “The rationale behind this approach was the intended analysis of the secondary outcomes that might occur after the primary outcome; furthermore, it allowed for additionally analyzing multiple tooth loss,” the researchers wrote.

To analyze data, researchers applied the statistical methods of the Kaplan-Meier survival analysis, intention-to-treat analysis, per-protocol analysis, per-protocol/as-treated analysis, and Cox regression analyses. They observed 189 tooth losses, including 61 first tooth losses after treatment. The number of teeth lost was similar in both groups, and researchers could not detect particular patterns or differences relative to underlying causes.

Researchers concluded that the study results lend support to the SDA concept and that the influence of the prosthetic management of the bilateral SDA relative to tooth loss, judging from the absence of outcome differences between the 2 prosthetic treatments, has been overestimated. “Both PRDPs retained with precision attachments and SDAs are viable management options,” they wrote.

In addition, in light of their conclusions, they advised making treatment decisions that appropriately weigh patient preferences.

Read the original article here.

 

Planmeca Calm

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Planmeca CALM (Correction Algorithm for Latent Movement) is a proprietary algorithm that addresses a doctor’s concerns over patient movement during a 3D scan. With Planmeca CALM, Planmeca cone beam computed tomography can analyze and compensate for the slight movement that can occur during a scan to provide improved diagnostic quality images. The addition of this feature (available for Planmeca ProMax 3D systems; check system requirements with your Planmeca representative) streamlines the imaging process, minimizing retakes while improving diagnosis. The important benefit to patients—less retakes equals less radiation while achieving better diagnostic images.

Learn more at Planmeca.com.

Digital Dentistry Symposium set for Feb. 20-21, 2018 in Chicago

All dental professionals are invited to attend the American College of Prosthodontists Digital Dentistry Symposium, Feb. 20-21 in Chicago. Featuring breakout sessions for novice, intermediate, and advanced users of digital technology, this symposium is designed for dental professionals who are interested in state-of-the-art digital solutions for the treatment of restorative patients. Topics include 3D diagnosis and treatment planning, clinical workflows, and design materials, with a focus on application in dental practice. Register at Prosthodontics.org or call 312-573-1260.

 
 
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JADA+ Specialty Scans and JADA+ Scans

JADA+ Specialty Scans and JADA+ Scans are quarterly newsletters updating dentists on the latest research in selected specialties and disciplines in dentistry. ADA Publishing and the consulting editors from the represented specialties and disciplines aggregate and summarize research from previously published materials, each item attributed to its publication of origin. JADA+ Scan specialties and disciplines include endodontics, oral pathology, orthodontics, pediatric dentistry, periodontics, prosthodontics, radiology, cosmetic/esthetic and osseointegration. 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. View past issues here.

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