^{October 2017Abstracts}

 

 

 

 

 

Efficacy of an anti-discoloration system (ADS) in a 0.12% chlorhexidine mouthwash: A triple blind, randomized clinical trial

 

Elena Maria Varoni, phd, dmd, Marco Gargano, mphys, Nicola Ludwig, phd, mphys, Giovanni Lodi, phd, dmd, Andrea Sardella, md  &  Antonio Carrassi, md

 

Abstract: Purpose: To determine the efficacy of an anti-discoloration system (ADS) in a 0.12% chlorhexidine (CHX) mouthwash to reduce dental discoloration. Methods: A triple-blind, cross-over, randomized clinical trial was carried out in 22 healthy volunteers asked to perform oral rinses, twice a day for 21 days, using 0.12% CHX mouthwashes containing or not ADS (wash-out= 21 days). Dental discolorations were compared via spectroscopy (ΔE), and direct visual examination performed by the dentist and volunteers themselves. At 6 months, a further visual analysis on clinical images was carried out by the same volunteers and ad hoc recruited dental practitioners. Results: A slight discoloration was the most frequent finding, independent of the presence of ADS, while the few severe cases of staining were associated with CHX alone. ΔE values comparing dental color before and after treatments were similar for CHX (8.4±0.1) and CHX+ADS (8.6±0.9) rinses. Direct visual analysis showed no staining difference between the two mouthwashes. Six months later, volunteers’ self-evaluation of clinical pictures again did not detect any significant difference between treatments, while dental practitioners identified CHX+ADS as less discoloring (P< 0.05). Slight dental discoloration represents the most common side-effect of 0.12% CHX mouthwash, independent of the presence of ADS. Severe cases are possible, but very rare and mainly associated with CHX alone. (Am J Dent 2017;30:235-242).

 

 

 

 

Mail: Dr. Elena Maria Varoni, Department of Biomedical Science, Surgery and Dentistry, University of Milan, Milan, Italy.  E-mail: elena.varoni@unimi.it

 

 

 

 

 

 

Shear bond strength of different materials used as core build-up to ceramic

 

Bledar Lilaj, dmd, Alexander Franz, phd, Viktoria Dangl, dmd, Rinet Dauti dmd, Andreas Moritz, md, dmd & Barbara Cvikl, md, dmd

 

Abstract: Purpose: To determine the performance of a resin composite material specially developed for core build-ups in comparison with conventional restorative materials. Methods: 90 roughened ceramic blocs were divided into three groups; one group (n=30) was used for the core build-up material (Gradia Core) and the other two groups (n=30, each) were used for two conventional restorative materials (Tetric EvoCeram, Compoglass F). After adhesive fixation, specimens of each material were subdivided in accordance with the storage conditions (thermocycling or water storage). Shear bond strength was measured and fracture behavior was analyzed. Results: Gradia Core presented significantly higher shear bond strength values than the conventional restorative material Tetric EvoCeram, both after 24 hours water storage as well as after thermocycling. Compoglass F did not show any statistically significant differences compared to the other materials, independent of the storage condition. However, Compoglass F resulted in numerically higher shear bond values than Tetric EvoCeram, but lower shear bond values than Gradia Core. Within the same materials, no statistically significant differences occurred regarding the storage conditions. (Am J Dent 2017;30:243-247).

 

 

Mail: Dr. Barbara Cvikl, Department of Conservative Dentistry & Periodontology, Medical University of Vienna, Sensengasse 2a, A-1090 Vienna, Austria. E-mail: Barbara.cvikl@meduniwien.ac.at

 

 

 

 

Performance of CAD/CAM fabricated fiber posts in oval-shaped root canals: An in vitro study

 

Nino Tsintsadze, dds, Jelena Juloski, dds, phd, Michele Carrabba, dds, phd, Marella Tricarico, dds, phd, Cecilia Goracci, dds, phd, Alessandro Vichi, dds, msc, phd, Marco Ferrari, md, dds, phd  &  Simone Grandini, dds, phd

 

Abstract: Purpose: To assess the push-out strength, the cement layer thickness and the interfacial nanoleakage of prefabricated fiber posts, CAD/CAM fiber posts and metal cast posts cemented into oval-shaped root canals. Methods: Oval-shaped post spaces were prepared in 30 single-rooted premolars. Roots were randomly assigned to three groups (n=10), according to the post type to be inserted: Group 1: Prefabricated fiber post (D.T. Light-Post X-RO Illusion); Group 2: Cast metal post; Group 3: CAD/CAM-fabricated fiber post (experimental fiber blocks). In Group 3, post spaces were sprayed with scan powder (VITA), scanned with an inEos 4.2 scanner, and fiber posts were milled using an inLab MC XL CAD/CAM milling unit. All posts were cemented using Gradia Core dual-cure resin cement in combination with Gradia core self-etching bond (GC). After 24 hours, the specimens were sectioned perpendicular to the long axis into six 1 mm-thick sections, which were differentiated by the root level. Sections from six roots per group were used to measure the cement thickness and subsequently for the thin-slice push-out test, whereas the sections from the remaining four teeth were assigned to interfacial nanoleakage test. The cement thickness around the posts was measured in micrometers (µm) on the digital images acquired with a digital microscope using the Digimizer software. Thin-slice push-out test was conducted using a universal testing machine at the crosshead speed of 0.5 mm/minute and the bond strength was expressed in megaPascals (MPa). The interfacial nanoleakage was observed under light microscope and quantified by scoring the depth of silver nitrate penetration along the post-cement-dentin interfaces. The obtained results were statistically analyzed by Kruskal-Wallis ANOVA, followed by the Dunn’s Multiple Range test for post hoc comparisons. The level of significance was set at P< 0.05. Results: Statistically significant differences were found among the groups in push-out bond strength, cement thickness and interfacial nanoleakage (P< 0.05). CAD/CAM-fabricated fiber posts achieved retention that was comparable to that of cast metal posts and significantly higher than that of prefabricated fiber posts. The cement layer thickness around CAD/CAM-fabricated fiber posts was significantly lower than around prefabricated fiber posts, but higher than that around cast metal posts. Root level was not a significant factor for push-out strength in any of the groups, whereas it significantly affected cement layer thickness only in the prefabricated fiber post group. No differences were observed in interfacial nanoleakage between CAD-CAM fabricated and prefabricated fiber posts, while nanoleakage recorded in cast metal posts was significantly lower. (Am J Dent 2017;30:248-254).

 

 

Mail: Prof. Marco Ferrari, Department of Medical Biotechnologies, Division of Fixed Prosthodontics, Policlinico Le Scotte, University of Siena, viale Bracci, Siena 53100, Italy. E-mail: ferrarm@gmail.com

 

 

 

A randomized clinical study to evaluate the effect of an ultra-low abrasivity dentifrice on extrinsic dental stain

 

Sarah Young, bsc,  Stephen Mason, phd,  Jeffery L. Milleman, dds, mpa  &  Kimberly R. Milleman, bsed, ms

 

Abstract: Purpose: To investigate the stain-removal efficacy of an experimental ultra-low abrasivity anti-sensitivity dentifrice containing sodium tripolyphosphate (STP) and a cocamidopropyl betaine/sodium methyl cocoyl taurate deter-gent system. Methods: This was a single-center, examiner-blind, randomized, parallel-group study. Extrinsic dental stain was assessed on the facial surfaces of the six maxillary and six mandibular anterior teeth and the lingual surfaces of the six mandibular anterior teeth using the Macpherson modification of the Lobene Stain Index (MLSI). Treatments were: ultra-low abrasivity dentifrice [5% w/w KNO₃, 5% w/w STP, 1,100 ppm fluoride as sodium fluoride; relative dentin abrasivity (RDA) ~10; n=54]; moderate abrasivity fluoride dentifrice (1,100 ppm fluoride as sodium monofluorophosphate; RDA ~68; n= 57); higher abrasivity daily-use whitening dentifrice (1,100 ppm fluoride as sodium fluoride; RDA ~137; n= 57). Subjects brushed for 1 minute, twice daily, for 8 weeks. Results: Mean total MLSI [Area × Intensity (A×I)] change from baseline score at Weeks 4 and 8 was significant (P< 0.0001) for all groups. At Week 8, for the ultra-low abrasivity dentifrice versus the moderate and higher abrasivity dentifrices, mean total MLSI (A×I) scores (P< 0.0001), along with MLSI endpoints in facial, lingual, and interproximal regions (P= 0.0035 to P< 0.0001), favored the ultra-low abrasivity dentifrice. Dentifrices were generally well-tolerated. The ultra-low abrasivity dentifrice containing 5% STP reduced extrinsic dental stain more effectively than moderate or higher abrasivity dentifrices. (Am J Dent 2017;30:255-261).

 

 

 

Mail: Sarah Young, Oral Care Clinical Research, Research & Development, GSK Consumer Healthcare, St George’s Avenue, Weybridge, Surrey, KT13 0DE, United Kingdom.  E-mail:  sarah.l.young@gsk.com

 

 

 

Surface properties and color stability of incrementally-filled and bulk-fill composites after in vitro toothbrushing

 

Guangyun Lai, dds, phd, Liya Zhao, dds, Jun Wang, dds, phd  &  Karl-Heinz Kunzelmann, dds, phd

 

Abstract: Purpose: To evaluate the effect of simulated toothbrush abrasion on the surface gloss, the surface roughness and the color stability of incrementally-filled and bulk-fill composites. Methods: 48 dimensionally standardized composite specimens (n= 8/group) were made from four incrementally-filled composites (Tetric EvoCeram, IPS Empress Direct Enamel, Ceram X mono and Arabesk) and two bulk-fill composites (Quix fil and Tetric EvoCeram Bulk). Before and after toothbrushing simulation the surface gloss was measured by a glossmeter, the surface roughness was evaluated with a profilometer, and the color was measured using a spectrophotometer. Results: Before and after the toothbrush abrasion, IPS Empress Direct Enamel yielded the highest gloss value, while Ceram X mono exhibited the lowest gloss value. Quix fil showed the highest Ra value before the toothbrushing simulation, however, it showed similar Ra value with Ceram X mono and Arabesk after the toothbrushing simulation. IPS Empress Direct Enamel showed the lowest ∆E after the simulated toothbrushing. Tetric EvoCeram Bulk showed similar gloss value, Ra value, and ∆E to Tetric EvoCeram after the toothbrushing simulation. Simple regression analysis showed no correlation between the roughness and the gloss, but it showed a positive linear relationship between ΔE and ΔRa. (R²= 0.863, P= 0.027). (Am J Dent 2017;30:262-266).

 

 

Mail: Dr. Jun Wang, Department of Pediatric Dentistry, Shanghai Key Laboratory of Stomatology, Shanghai Research Institute of Stomatology, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, 639 Zhizaoju Road, Shanghai 200011, P.R. China. E-mail: junwang0203@126.com

 

 

 

 

A clinical, randomized, double-blind study on the use of toothpastes immediately after at-home tooth bleaching

 

Cristiane de Melo Alencar, dds, Ranna Castro da Silva, dds, Jesuína Lamartine Nogueira Araújo, dds, msc. phd,

Ana Daniela Silva da Silveira, dds, msc, phd  &  Cecy Martins Silva, dds, msc, phd

 

Abstract: Purpose: To evaluate the effect of 5% potassium nitrate containing 2% sodium fluoride and 10% strontium chloride on tooth sensitivity and color change after at-home bleaching treatment across 3 months of follow-up. Methods: 60 subjects were randomly allocated by numerical draw into three groups (n= 20): (1) Control, treated with 22% carbamide peroxide (CP) followed by application of a toothpaste without active ingredient: (2) Nitrate, treated with 22% CP followed by application of a toothpaste containing 5% potassium nitrate and 2% sodium fluoride: (3) Strontium, treated with 22% CP followed by application of a toothpaste containing 10% strontium chloride. An air jet was used to evaluate post-bleaching sensitivity associated with a modified visual analogue scale (VAS). A spectrophotometer was used to measure the color of the maxillary incisors. Results: The Friedman vs Kruskal-Wallis tests showed that the tooth sensitivity associated with the experimental groups during 10 days of bleaching treatment was lower than that reported with the Control (P= 0.043). ANOVA showed that variation in ΔE revealed no significant difference in tooth color among the groups for the different evaluation times (P= 0.923). (Am J Dent 2017;30:267-271).

 

 

 

 

 

 

 

Mail: Dr. Cecy Martins Silva, School of Dentistry, Federal University of Para, Augusto Correa Street No. 1, Guamá, Belém, PA, Brazil, 66075-110.  E-mail:  cecymsilva@gmail.com

 

 

 

 

 

 

Clinical effect of a manual toothbrush with tapered filaments on dental plaque and gingivitis reduction

 

LONGXING NI, DDS, PHD, RONGYING TANG, DDS, TAO HE, DDS, PHD, JINLAN CHANG, BS, JIAHUI LI, BS, SARAH LI, BS, RENZO ALBERTO CCAHUANA-VASQUEZ, DDS, PHD, RICHARD CHENG, PHD & JULIE GRENDER, PHD

 

ABSTRACT: Purpose: To evaluate the anti-plaque efficacy (Study 1) and the anti-gingivitis efficacy (Study 2) of a manual toothbrush with tapered bristles compared to marketed control manual toothbrushes. Methods: Studies 1 and 2 were independent, randomized and controlled, single-center, examiner-blind clinical trials in generally healthy adults. Study 1 included a 2-day acclimation period, followed by a 5-day twice daily toothbrushing test phase with the assigned brush. Baseline and Day 5 pre- and post-brushing plaque levels were assessed via Turesky Modified Quigley-Hein Plaque Index (TMQHPI). In Study 2, subjects with existing gingivitis brushed with their assigned toothbrush twice daily for 4 weeks. Gingivitis was measured using the Mazza Modification of the Papillary Bleeding Index at Baseline and Weeks 2 and 4. In both trials, subjects were randomly assigned to either the manual toothbrush with tapered bristles (Oral-B Super Thin Indicator toothbrush, OM159) or the marketed control (Study 1: Oral-B Complete Clean & Sensitive toothbrush; Study 2 Crest Pro-Health Complete 7 Brush 35 toothbrush) for use with a regular fluoridated dentifrice. Results: 40 (Study 1) and 63 (Study 2) subjects were randomized in each trial. In Study 1, both the tapered bristle and marketed control brushes provided significant (P< 0.0001) mean whole mouth plaque reductions at Day 1 and Day 5 post-brushing relative to pre-brushing as measured via TMQPHI, with no between-brush significant differences. Both groups showed a significant reduction in Day 5 post-brushing mean plaque scores versus Day 1 pre- brushing mean plaque scores (P< 0.0001), but the reductions were not significantly different between groups (P= 0.4274). In Study 2, both the tapered bristle brush and the marketed control brush produced significant (P< 0.0001) reductions in both gingivitis and number of gingival bleeding sites at both Weeks 2 and 4 versus baseline. At Week 4, the tapered filament toothbrush group showed 8.6% less gingivitis (P= 0.0017) and 33.4% fewer bleeding sites (P= 0.0030) versus the control brush. All toothbrushes were well-tolerated. (Am J Dent 2017;30:272-278).

 

 

 

 

Mail: Dr. Tao He, Procter & Gamble, 8700 Mason-Montgomery Road, Mason, OH 45040, USA. E-mail: he.t@pg.com

 

 

 

Comparison of enamel bond fatigue durability of universal adhesives and two-step self-etch adhesives in self-etch mode

 

Akimasa Tsujimoto, dds, phd,  Wayne W. Barkmeier, dds, ms,  Yumiko Hosoya, dds, phd,  Kie Nojiri, dds, phd, Yuko Nagura, dds,  Toshiki Takamizawa, dds, phd,  Mark A. Latta, dmd, ms  &  Masashi Miyazaki, dds, phd

 

Abstract: Purpose: To comparatively evaluate universal adhesives and two-step self-etch adhesives for enamel bond fatigue durability in self-etch mode. Methods: Three universal adhesives (Clearfil Universal Bond; G-Premio Bond; Scotchbond Universal Adhesive) and three two-step self-etch adhesives (Clearfil SE Bond; Clearfil SE Bond 2; OptiBond XTR) were used. The initial shear bond strength and shear fatigue strength of the adhesive to enamel in self-etch mode were determined. Results: The initial shear bond strengths of the universal adhesives to enamel in self-etch mode was significantly lower than those of two-step self-etch adhesives and initial shear bond strengths were not influenced by type of adhesive in each adhesive category. The shear fatigue strengths of universal adhesives to enamel in self-etch mode were significantly lower than that of Clearfil SE Bond and Clearfil SE Bond 2, but similar to that OptiBond XTR. Unlike two-step self-etch adhesives, the initial shear bond strength and shear fatigue strength of universal adhesives to enamel in self-etch mode was not influenced by the type of adhesive. (Am J Dent 2017;30:279-284).

 

 

Mail: Dr. A. Tsujimoto, 1-8-13 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan. E-mail: tsujimoto.akimasa @nihon-u.ac.jp

 

 

 

Review Article

The role of adhesive materials and oral biofilm in the failure of adhesive resin restorations

 

Roberto Pinna, dds, phd. Paolo Usai, dds, Enrica Filigheddu, dds, phd, Franklin García-Godoy, dds, ms, phd, phd &  Egle Milia, md, dds

 

Abstract: Purpose: To critically discuss adhesive materials and oral cariogenic biofilm in terms of their potential relevance to the failures of adhesive restorations in the oral environment. Methods: The literature regarding adhesive restoration failures was reviewed with particular emphasis on the chemistry of adhesive resins, weakness in dentin bonding, water fluids, cariogenic oral biofilm and the relations that influence failures. Particular attention was paid to evidence derived from clinical studies. Results: There was much evidence that polymerization shrinkage is one of the main drawbacks of composite formulations. Stress results in debonding and marginal leakage into gaps with deleterious effects in bond strength, mechanical properties and the whole stability of restorations. Changes in resins permit passage of fluids and salivary proteins with a biological breakdown of the restorations. Esterases enzymes in human saliva catalyze exposed ester groups in composite producing monomer by-products, which can favor biofilm accumulation and secondary caries. Adhesive systems may not produce a dense hybrid layer in dentin. Very often this is related to the high viscous solubility and low wettability in dentin of the hydrophobic BisGMA monomer. Thus, dentin hybrid layer may suffer from hydrolysis using both the Etch&Rinse and Self-Etching adhesive systems. In addition, exposed and non-resin enveloped collagen fibers may be degraded by activation of the host-derived matrix metalloproteinase. Plaque accumulation is significantly influenced by the surface properties of the restorations. Biofilm at the contraction gap has demonstrated increased growth of Streptococcus mutans motivated by the chemical hydrolysis of the adhesive monomers at the margins. Streptococcus mutans is able to utilize some polysaccharides from the biofilm to increase the amount of acid in dental plaque with an increase in virulence and destruction of restorations. Stability of resin restorations in the oral environment is highly dependent on the structure of the monomers used in composite and adhesive systems. Still, the issues related to microleakage of fluids into the gap and bacteria leaching from the surface of composites represent the main causes of failure of adhesive restorations. (Am J Dent 2017;30:285-292).

 

 

 

 

Mail: Prof. Egle Milia, Department of Biomedical Science, University of Sassari, Sassari, Italy. E-mail: emilia@uniss.it