Thursday, June 29, 2017

The Effect of Temporary Cement Cleaning Methods on the Retention of Crowns


Abstract

Purpose

To evaluate the effect of temporary cement cleaning methods on the retention of cemented crowns using zinc phosphate cement and resin-modified glass ionomer cement.

Materials and Methods

Forty titanium specimens were fabricated to simulate prepared molars with minimally retentive taper. The Ni-Cr cast crowns were fabricated, temporarily cemented, and separated. The specimens were divided into four groups according to the temporary cement cleaning method (n = 10) as follows: control group (no temporary cementation), orange solvent group, ultrasonic cleaning group, and air-abrasion group. After the cleaning procedures, the specimens were cemented with definitive cements (zinc phosphate cement and resin-modified glass ionomer, RMGI, cement) and subjected to thermocycling (5000 cycles, 5-55°C, dwell time, 10 seconds). The tensile bond strength of each specimen was measured using a universal testing machine, and the results were analyzed using the Kruskal-Wallis and Mann-Whitney U test (α = 0.05).

Results

When cemented with zinc phosphate cement, the statistical analysis showed that the value of the air-abrasion group was significantly higher than those of the other groups (p < 0.01). There was no statistically significant difference among the other groups. When cemented with RMGI cement, the air-abrasion group showed the lowest value, and the control group showed the highest value (p < 0.01). The difference between the ultrasonic cleaning group and the orange solvent group was not statistically significant.

Conclusion

The use of temporary cement did not have a significant influence on retention of permanently cemented crowns when zinc phosphate cement was used for permanent cementation. Airborne-particle abrasion after provisional cementation improved retention of crowns cemented with zinc phosphate cement; however, the use of temporary cement significantly decreased retention of permanently cemented crowns when RMGI cement was used regardless of the temporary cement cleaning method.

Wednesday, June 28, 2017

Effect of Split-File Digital Workflow on Crown Margin Adaptation


Abstract

Purpose

Computer-aided design/computer-aided manufacturing (CAD/CAM) is becoming increasingly integrated into dental practice workflow at a pace that exceeds scientific validation. The aim of this study is to evaluate a complete digital split-file protocol relative to segmental digital and analog techniques for restoring a single maxillary anterior edentulous space with custom abutment and crown.

Materials and Methods

Four treatment workflows were assessed: complete digital (CD), segmental digital (SD), milled wax (AM), and heat pressed and hand waxed (AH) and heat pressed. The CD workflow “split” an abutment and crown into separate files to fabricate a zirconia abutment and both zirconia/lithium disilicate crown restorations. The SD workflow scanned the existing abutment for design of segmental restorations in zirconia, lithium disilicate, and milled wax (AM). The AH specimens were conventionally hand waxed. Both the AM and AH specimens were heat pressed with lithium disilicate. All restorations were evaluated with standardized measurements using scanning electron microscopy (SEM) as manufactured without internal adjustments and after manual adjustment. The number of adjustments, adjustment time, and location of adjustments were recorded. One-way ANOVA with repeated measures was used to report geometric means with 95% confidence intervals.

Results

The mean marginal gap after adjustment of the CD group was 69 μm, with an upper bound (UB) of 79 μm and a lower bound (LB) of 60 μm. SD group mean was 26 μm with an UB of 31 μm and LB of 22 μm. The AM group mean was 32 μm, with an UB of 49 μm and a LB of 20 μm; AH group mean of 26 μm with an UB of 34 μm and a LB of 20 μm. The SD, AM, and AH workflows were statistically similar (p = 1.000), and the CD workflow was statistically greater than the other three (p < 0.001).

Conclusions

The split-file (CD) protocol results in marginal gap size within clinical standards after adjustment; however, 52 of the 60 digitally produced restorations showed a horizontal marginal offset that required adjustment for proper contours.

Tuesday, June 27, 2017

V-Posil Time-Optimized VPS Impression System



Maximum Precision in Up to 30% Less Chair Time

VOCO presents V-Posil, the maximum precision VPS impression system with optimized timing for reduced headaches and chair time.

V-Posil is flavorless and offers up to 2-minutes of adjustable working time, giving the practitioner control over the pace of the procedure while the abbreviated 2-minute thermo-activated set time improves patient comfort and limits procedural time.  Likewise, V-Posil’s rapid snap-set benefits both the practitioner and the patient by reducing the time spent in the critical zone by up to 50%, minimizing potential distortion due to human error, which results in less costly retakes. Through V-Posil’s optimized timing VOCO has been able to combine the working time of a regular-set with the short setting time of a fast-set in one single material.

With a low polyether-like contact angle of less than TEN degrees (<10 span="">°), V-Posil’s superior hydrophilicity displaces fluids (saliva, blood, etc.) to create an enhanced contact to the dental anatomy, yielding more precise impressions.  Additionally, V-Posil provides exceptional tear strength and elastic recovery (99.6%) to ensure dimensional accuracy of the impression after its removal.  Lab Technicians will appreciate V-Posil’s unique post-set contact angle of less than SIX degrees (<6 a="" accurate="" better="" ensures="" fitting="" for="" hydrophilicity="" models="" more="" post-set="" providing="" restorations.="" span="" stone="" that="">

Featuring four different viscosities including two tray materials in V-Posil Putty Fast and Heavy Soft Fast and two wash materials in V-Posil Light Fast and X-Light Fast, V-Posil’s indications include the full range of impression techniques as well as reline/rebase impressions and impressions for removable dental prostheses. All four viscosities are available in 50ml cartridge refills while the V-Posil Heavy Soft Fast, formulated for both easy loading and removal after it is set, is also available in the 380ml automix Dynamic Dispenser cartridge. 

Manufacturer:                         VOCO America Inc.
Contact Number:         1-888-658-2584
Contact Email:            infousa@voco.com

Monday, June 26, 2017

Taub Products Announces Release of New Eyewash station



Jersey City, NJ: June 22, 2017 - TAUB Products, a long-time manufacturer of dental laboratory and restorative products, has introduced a low-profile emergency eyewash station that adapts to a wide range of office and laboratory faucets. The new station provides instant access to a single aerated water jet, flushing the eyes and washing the face of chemical or particulate contamination.

Jordan Taub, Vice President of TAUB, stated, “The unique design allows water to flow normally downward for washing hands, and during an emergency, the user can quickly rotate it upwards, providing a soft stream of water that will wash the face. The user places the water stream on the brow of the nose and both eyes receive an effective rinse.”

Setting this apart from dual-jet designs, the key features of the product include a single rotating nozzle to wash eyes and face, a low-profile modern design that fits most standard faucets, a flow rate of 1.2 gallons per minute, which exceeds ANSI standards, and a design that prevents standing water, thus reducing the chance for mold development.

TAUB Products is celebrating its 65th year in business. TAUB provides innovative, high-quality solutions for dental professionals. For more information on TAUB and its products, call 800-828-2634, or go to www.taubdental.com.

Friday, June 23, 2017

A Novel Evidence-Based Periodontal Prognosis Model

,

Abstract

Objective

Patients with periodontal disease and the dental professionals responsible for their care want to know which teeth are expected to respond favorably to periodontal treatment and which teeth are likely to be lost in the short and long term. A number of different periodontal prognosis systems have been previously proposed but do not consider important patient-level factors, such as smoking and diabetic control, in the calculation of the expected outcome and often use subjective measures that introduce potential inaccuracies. The aim of this report is to translate the best available evidence on periodontal prognosis into a clinical model to facilitate decision-making and improve patient outcomes.

Methods

Criteria for an ideal prognostic system were proposed and used to assess the previously reported models. With an emphasis on the inclusion of patient-level modifiers (PLMs) and the exclusive use of objective parameters, a new evidence-based model was developed.

Results

This report proposes a new tooth-level prognosis model that uses 9 evidence-based quantifiable parameters to provide a prognosis of secure, doubtful, poor, or irrational to treat. Six tooth-level risk predictors (bone loss:age, pocket depth, furcation involvement, infrabony defects, anatomical factors, and mobility) and 3 PLMs (smoking, diabetes, and bleeding on probing) are used to determine the expected course of disease with specific reference to the suitability of the tooth for future dental treatment.

Conclusions

PLMs must be considered when determining the prognosis of a tooth with periodontal disease. The model proposed in this report is based on the best available evidence for factors affecting tooth survival and has been designed to be as simple and objective as possible to facilitate its adoption in clinical practice. It will be retrospectively and prospectively validated to determine its ability to accurately predict the course of disease.

Thursday, June 22, 2017

Erbium Laser Technology vs Traditional Drilling for Caries Removal: A Systematic Review with Meta-Analysis



Abstract

Objective

The study aimed to assess the efficacy of erbium laser technology compared with traditional drilling for caries removal.

Methods

A systematic search was conducted through Medline via PubMed, Embase, Cochrane databases, CNKI till December 2016. Randomised controlled trials, quasi-randomized controlled trials, or controlled clinical trials with data comparing the efficacy of erbium laser technology versus traditional drilling for caries removal were included.

Results

Fourteen studies were selected in our meta-analysis. Erbium laser technology showed an increased time when removing caries compared with drilling (mean difference: 3.48, 95% confidence interval: 1.90-5.06, P < .0001). However, erbium laser technology reduced the requirement for local anesthesia (risk ratio: 0.28, 95% confidence interval: 0.13-0.62, P = .002). Erbium laser technology was also not significantly different to traditional drilling with regard to restoration loss, pulpal vitality, and postoperative sensitivity.

Conclusions

Erbium laser technology showed an increased time for cavity preparation compared with traditional drilling. However, erbium laser technology reduced the requirement for local anesthesia. There was no significant difference between erbium laser technology and traditional drilling regarding restoration loss, pulpal vitality, and postoperative sensitivity.

Wednesday, June 21, 2017

CAD/CAM-fabricated ceramic implant-supported single crowns made from lithium disilicate: Final results of a 5-year prospective cohort study


Abstract

Background

All-ceramic bilayer systems suffer from technique-sensitivity, resulting in increased technical complication rates. This might be overcome by monolithic reconstructions, facilitating digital workflows.

Purpose

To evaluate the clinical and patient-reported outcome of CAD/CAM-fabricated implant-supported single crowns (ISCs) made of lithium disilicate (LS2) cemented on ceramic implants 5 years after implant installation.

Materials and methods

Twenty-four patients were included in the study. All participants received a one-piece ceramic implant in anterior (4 incisors) and posterior regions (10 premolars, 10 molars). LS2 crowns were computer-aided designed (CAD), manufactured (CAM) and adhesively luted onto the implants. Follow-ups were performed yearly up to 60 months after implant installation. The survival/success rates of the restorations were calculated according to modified US Public Health Service criteria as follows: Clinically relevant defects that could be repaired intraorally were accepted for survival, whereas small-area chippings, roughness (ø < 2 mm), slightly soundable marginal gaps, minimal undercontours/overcontours, and tolerable color deviations were accepted for success. Kaplan-Meier plots were used for the success/survival analyses. Furthermore, patient-reported outcome measures (PROMs) were assessed by applying visual analog scales (VAS). Linear (PROMs) and logistic (USPHS criteria) mixed models were fitted to evaluate time effects on response variables.

Results

Twenty-two ISCs could be evaluated 55.2 ± 4.2 months after prosthetic delivery. Two patients were reported as drop-outs (1 died, 1 moved abroad). No failures were observed, resulting in 100% survival. At two ISCs, a major-roughness had to be treated. This resulted in a Kaplan-Meier success estimate of 91.7% (95%CI: 70.6%-97.9%). Compared with pretreatment, all surveys at prosthetic delivery except for self-esteem (P = .375) showed significantly improved VAS scores. No decrease in satisfaction could be observed over time until the end of follow-up (P ≥ .056).

Conclusion

Concerning survival/success rates and PROMs, the evaluated crown-implant system showed favorable mid-term results. To date, there are no comparable data available for implant-supported ISCs made of LS2.