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Dose-Response Effect of Fluoride Dentifrices on De-/Remineralization of Root Dentine in situ

Caries Research
Published online: October 19, 2020

Abstract

The present study aimed to evaluate the effect of fluoride (F) dentifrice with different F concentrations on root dentine de-/remineralization. Ten healthy volunteers took part in this randomized, double-blinded, cross-over, and split-mouth in situ experimental study. During 4 phases of 7 days, they wore a palatal appliance containing 4 bovine dentine blocks (2 sound and 2 with caries) of 4 × 4 × 2 mm. Treatments were performed with silica-based dentifrices containing 0, 700, 1,300, and 5,000 µg F/g (F as NaF). To provide a cariogenic challenge, a 20% sucrose solution was dripped 3 and 8 times daily on the carious-like and sound blocks, respectively. After each experimental phase, the percentage of surface hardness loss (%SHL) or recovery (%SHR) was calculated and the fluoride concentration in the biofilm was determined. The statistical analysis was performed using ANOVA and the Tukey post hoc test with p at 5%. The relationship between variables was analyzed by linear regression. The results showed a lower %SHL when 5,000 µg F/g dentifrice was used but without a statistically significant difference from the conventional one (1,300 µg F/g). Regarding remineralization and F in biofilms, the high-fluoride dentifrice was expressively superior in mineral replacement on the surface and in the F concentration in the biofilms, respectively, compared to the other 3 products (p < 0.05). Also, a significant linear fit between mineral loss/gain, F in biofilms, and fluoride concentration in the dentifrices could be observed. In conclusion, a dose-response F effect was observed, and the high-fluoride dentifrice was effective in enhancing root dentine remineralization in this short-term in situ study.

 

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Mechanism linking gum disease to heart disease, other inflammatory conditions discovered

Researchers at the University of Toronto have found first evidence that neutrophil immune cell activity is the missing link connecting periodontal disease with heart disease, cancer, and other inflammatory conditions

University of Toronto – Faculty of Dentistry

Research News

IMAGE

IMAGE: Neutrophil activation is now believed to be at the root of overactive inflammatory responses, and links conditions such as periodontal disease and heart disease view more 

Credit: Noah Fine

(TORONTO, ON) Oct. 20, 2020 — The link between periodontal (gum) disease and other inflammatory conditions such as heart disease and diabetes has long been established, but the mechanism behind that association has, until now, remained a mystery. This month, a team of scientists and clinicians led by the University of Toronto’s Faculty of Dentistry say they’ve found the reason why — and it’s related to the body’s own hyperactive immune response. The findings were published in October in the Journal of Dental Research.

HYPERACTIVE STATE

Science has already established that state of your oral health is an important indicator of overall health. "There are statistically significant correlations between periodontitis (oral inflammatory disease) and systemic diseases ranging from diabetes to cardiovascular diseases," says Howard Tenenbaum, professor at the University of Toronto’s Faculty of Dentistry, and chief dentist at Sinai Health Systems in Toronto, who is one of the authors of the study.

To find what links those conditions, the researchers focused on the behaviours of cells primarily activated by gum disease — neutrophils, which are cells of the innate immune system. Through in vivo models, the researchers found that the immune system releases an abundance of these neutrophils to tackle the bacterial infections responsible for periodontitis, more commonly known as gum disease.

Activated to fight an oral infection, a systemic effect was noted: once periodontal inflammation was present, an overabundance of neutrophils circulated, ‘primed’ for attack. The hyper-vigilant immune system then responds with an excess of force to any secondary infection.

"It’s almost as if these white blood cells are in second gear when should be in first," says Michael Glogauer, professor at the University of Toronto’s Faculty of Dentistry and the study’s senior author.

That’s when the body becomes susceptible to damage from secondary inflammatory conditions. With the immune system already primed by the neutrophils for attack, a secondary event causes those immune cells to destroy affected tissues and organs.

"The [neutrophils] are much more likely to release cytokines much more quickly, leading to negative outcomes," adds Glogauer, who is also dentist-in-chief at the University Health Network and head of dental oncology at Toronto’s Princess Margaret Cancer Centre.

Produced initially in in vivo models, the findings were confirmed through a controlled clinical experiment.

ORAL HEALTH KEY TO OVERALL HEALTH

The study’s findings underscore the importance of oral health as a vital indicator of potential complications for other inflammatory conditions, as well as disease model outcomes.

"We believe this is the mechanism by which oral hygiene can impact vulnerability to unrelated secondary health challenges," says lead author Noah Fine, a postdoctoral fellow at the University of Toronto’s Faculty of Dentistry. "Neutrophil (immune) priming throughout the body can connect these seemingly distinct conditions," he says.

The study also may have important ramifications for an inflammatory disease at the top of everyone’s mind these days: COVID-19.

"There is evidence out there that patients with periodontal disease may be much more likely to have negative outcomes with COVID-19," explains Glogauer. The current study could provide some clues as to why: "Neutrophils are the cells that are at prime risk of causing cytokine storms. That’s the exact cell we show is primed with people with periodontal disease," he explains.

Research into the relationship between neutrophils and inflammation is ongoing.

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Impact of irrigation solutions on the apical sealing potential of different endodontic sealers used with the continuous-wave obturation technique: An In vitro study

El Sayed MA. Impact of irrigation solutions on the apical sealing potential of different endodontic sealers used with the continuous-wave obturation technique: An In vitro study. Eur J Gen Dent 2020;9:134-40

 Aim: This study is aimed to evaluate the impact of three irrigating solutions on the apical sealing ability of three endodontic sealers.  

 

Materials and Methods: One hundred maxillary central incisors were decoronated, and their roots were assigned into three experimental groups (n = 30 each) according to the nature of the irrigating solution and two control groups (n = 5 each). Each experimental group was divided equally into three subgroups (n = 10 each) according to the type of root canal sealer. All root canals were instrumented using ProTaper Universal rotary system and irrigated with 3% sodium hypochlorite (NaOCl/Group 1), 3% hydrogen peroxide (H2O2/Group 2), and 2% chlorhexidine gluconate (CHX/Group 3). The final irrigating solutions for all groups were 17% ethylenediaminetetraacetic acid (EDTA) and distilled water. The continuous-wave technique was used to fill the prepared canals with the following materials: MTA-Fillapex/Gutta-percha (Subgroup A), AH Plus/Gutta-percha (Subgroup B), and Realseal SE/Realseal (Subgroup C). The microleakage was assessed after 72 hours using the linear dye penetration method. The results were statistically analyzed with one-way analysis of variance. 

 

Results: Significant differences were found only between the experimental groups (P < 0.05). All root canal sealers after irrigation with 3% H2O2 showed the lowest amount of leakage. The highest apical leakage was observed when 3% NaOCl and 2% CHX were used.  

 

Conclusions: The type of irrigating solution could affect the apical sealing ability of experimental sealers used with the continuous-wave obturation technique. Root canal irrigation with 3% H2O2+17% EDTA increased the apical sealing ability of all root canal sealers. Root canal irrigation with 3% NaOCl or 2% CHX +17% EDTA decreased the apical sealing ability of all root canal sealers.

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10.9-year survival of pressed acid etched monolithic e.max lithium disilicate glass-ceramic partial coverage restorations: Performance and outcomes as a function of tooth position, age, sex, and the type of partial coverage restoration (inlay or onlay)

The Journal of Prosthetic Dentistry

Available online 2 October 2020

The Journal of Prosthetic Dentistry

Abstract

Statement of problem

Long-term clinical data on the survival of pressed lithium disilicate glass ceramic when used with partial coverage restorations and the effect that different technical and clinical variables have on survival are sparse.

Purpose

The purpose of this clinical study was to determine the 10.9-year survival of pressed lithium disilicate glass ceramic partial coverage restorations and associated clinical parameters on outcomes.

Material and Methods

Individuals requiring single unit defect-specific partial coverage restorations in any area of the mouth were recruited in a clinical private practice. Participants were offered the options of partial coverage cast gold or glass-ceramic (lithium disilicate) restorations. Only participants that chose glass-ceramic partial coverage restorations were included in the study. The overall survival of the glass-ceramic restorations was assessed by the clinical factors (participant’s age, sex, dental arch, tooth position in dental arch, type of partial coverage restoration, and ceramic thickness) determined at recall. The effect of this clinical parameters was evaluated by using Kaplan-Meier survival curves accounting for attrition bias and other reasons for failure. The statistical significance of differences between parameters was determined by using the log rank test (α=.05).

Results

A total of 304 participants requiring 556 lithium disilicate restorations were evaluated. The mean age for the participant at the time of restoration placement was 62 with a range of 20 to 99 years, 120 were men and 184 were women. A total of 6 failures (bulk fracture or large chip) requiring replacement were recorded with the average time to failure of 2.4 (0.8-9.2) years. The total time at risk computed for these units was 1978.9 years providing an estimated failure risk of 0.3% per year. The 10-year estimated cumulative survival was 95.6%.

The estimated cumulative survival of inlays (n=246) and onlays (n=305) were 93.9% and 98.3%, at 9.9 and 9.8 years, respectively (P<.05). Of the 6, there were 3 failures recorded for the partial coverage inlay restorations. The total time at risk for these inlays was 786.79 years providing an estimated risk of 0.38% per year. The other 3 failures recorded occurred for the partial coverage onlay restorations. The total time at risk for the onlays was 1032.17 years providing an estimated risk of 0.29% per year. The failures occurred in the molar region only. There were no failures recorded for the anterior partial coverage inlays (n=5). The total time at risk computed for the anterior units was 21.55 years providing an estimated risk of 0% per year.

There was no statistically significant difference in the survival of partial coverage restorations among men and women, different age groups, or position in the dental arch. The thickness of the restoration had no influence on the survival of glass ceramic partial coverage restorations.

Conclusions

Pressed lithium disilicate defect-specific partial coverage restorations reported high survival rate over the 10.9-year period with an overall failure rate of 0.3% per year and limited to the molar teeth. Risk of failure at any age was minimal for both men and women.

 

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Carestream Dental Announces New Integration with exocad Smile Creator

 

 

                          


 

ATLANTA—Carestream Dental is empowering practitioners to plan an ideal smile from a digital impression thanks to a preferred partnership with exocad Smile Creator, a state-of-the-art smile solution that’s now integrated into the Carestream Dental’s product portfolio.

 

Once a patient’s teeth have been scanned with either a CS 3600 or CS 3700 intraoral scanner, the Smile Creator can be directly accessed from Carestream Dental’s CS Imaging and CS ScanFlow software, streamlining and simplifying the smile design process. Users can also upload patient photos that can be aligned with their digital impressions.

 

Then, the smile can be designed using realistic 2D tooth shapes from exocad’s extensive tooth library. Facial analysis with help lines and proportional guides help the user design the ideal smile for the patient’s individual anatomy. Aesthetic relationships between the patient’s teeth, smile and face can be easily evaluated, offering practitioners a realistic perspective for a restorative treatment plan.

 

“Doctors must consider all angles of a case, from whether it’s prosthetically possible to how natural-looking the final restoration is,” Ed Shellard, D.M.D., chief dental officer, Carestream Dental said. “This new integration with exocad Smile Creator gives doctors complete control over design and serves as the perfect foundation for future prosthetic work while impressing and exciting patients with what their new smile could look like.”    

 

The 2D designs can then be viewed in 3D in real time from different angles, providing maximum predictability and letting patients approve their new smiles before agreeing to treatment. The advantage is clear: Highly predictable esthetic and functional results.

 

“The future of dentistry lies in technology and partnerships like this,” Shellard said. “Data is captured, assessed and interpreted in ways that give doctors more confidence and gets patients excited about digital dentistry.”

 

“This product sets the new benchmark for future communication between dental technicians, dentists and patients – particularly when it comes to designing esthetic anterior restorations,” Tillmann Steinbrecher, CEO, exocad, said. “The collaboration with Carestream Dental supports our goal of providing technology that helps clinicians take maximum advantage of digital processes”.

 

Smile Creator is fully integrated into exocad’s CAD software platform.

 

This new integration with exocad Smile Creator enhances Carestream Dental’s CS Solutions portfolio, its CAD/CAM line, to give practices more options for their restorative workflow. To learn more about CS Solutions, visit carestreamdental.com. To learn more about exocad, visit exocad.com

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About exocad

exocad GmbH is a dynamic and innovative software company committed to expanding the possibilities of digital dentistry and providing OEMs (Original Equipment Manufacturers) with flexible, reliable, and easy-to-use CAD/CAM software for dental labs and dental practices. exocad software has been chosen by leading OEMs worldwide for integration into their dental CAD/CAM offerings, and thousands of exocad DentalCAD licenses are sold each year. For more information and a list of exocad reseller partners, please visit exocad.com.

 

About Carestream Dental

Carestream Dental is committed to transforming dentistry, simplifying technology and changing lives. In this pursuit, we focus on providing the latest in high-quality scanning technology, the smartest chairside systems, the most intuitive practice management software, incredibly accurate imaging software and the data intelligence that helps continually refine patient outcomes. And we offer these solutions for the full range of dental and oral health professionals. For more information please visit carestreamdental.com.

 

 

 

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An alternative method for immediate implant-supported restoration of anterior teeth assisted by fully guided templates: A clinical study

The Journal of Prosthetic Dentistry

Available online 30 September 2020

The Journal of Prosthetic Dentistry

Abstract

Statement of problem

Immediate implant-supported restorations have become a common treatment strategy in the esthetic zone; however, improvements are necessary in the techniques used to fabricate interim prostheses.

Purpose

This clinical study evaluated an alternative method for the immediate restoration of anterior teeth by using a fully guided template.

Material and methods

Twenty-five participants were enrolled, and 30 implants were inserted by using fully guided templates. Eleven participants and 14 implant sites were treated with immediate implant placement. Fourteen participants and 16 implant sites were treated with delayed implant placement. The same method was used for immediate restoration in all the participants. A postoperative cone beam computed tomography (CBCT) scan was compared with the preoperative planning to measure the deviation between the placed and the planned implants. The independent t test was used for the comparison of immediate and delayed implant placement (α=.05). Any complications occurring in the following 3 months were also recorded.

Results

None of the interim prostheses needed significant adjustments and were successfully installed on implants after the surgery. The overall mean deviations in 3D coronal, buccolingual coronal, mesiodistal coronal, 3D apical, buccolingual apical, mesiodistal apical, depth, and angle were 0.6 ±0.3 mm, 0.4 ±0.2 mm, 0.2 ±0.1 mm, 1.0 ±0.4 mm, 0.7 ±0.4 mm, 0.3 ±0.2 mm, 0.4 ±0.3 mm, and 1.9 ±1.1 degrees, respectively. The linear and angular deviations exhibited no significant differences (P>.05) between immediate and delayed implant placement. No complications developed in the follow-up period.

Conclusions

In the anterior esthetic zone, this alternative method appears to be suitable for immediate restoration. The accuracy of fully guided surgery was clinically acceptable for the prefabricated interim prostheses and helped reduce postoperative chairside time.

 

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