^{February 2024 Abstracts}

Coffee-stained tooth enamel color restoration and surface abrasion with whitening and regular toothpaste

 

Soyeon Kim, ba,  Yeon-Jee Yoo, dds, phd,  Franklin Garcia-Godoy, dds, ms, phd, phd &  Young-Seok Park, dds, msd, phd

 

Abstract: Purpose: To evaluate the effectiveness of whitening toothpaste in restoring tooth color after coffee staining and its potential impact on enamel surfaces compared with regular toothpaste. Methods: Bovine tooth enamel specimens were prepared and stained with coffee solutions before undergoing brushing simulation with different toothpaste slurries (whitening, regular, reference). For precise evaluation, spectrophotometric measurements were taken at intervals to assess color changes using the CIELAB (Commission Internationale de l'Éclairage Lab*) color space. Additionally, profilometric measurements were taken to determine the impact of toothpaste type on the roughness and abraded depth of the enamel surface. To understand the effects of toothpaste and brushing on color change, surface roughness, and abraded depth, while also considering correlations between these factors, the findings were analyzed using mixed-effects models. Results: The whitening toothpaste group demonstrated the highest recovery rate (71%) after 10,000 brushstrokes, followed by the regular toothpaste group (48%) and the reference slurry group (43%). The mixed-effects model analysis revealed that the reference group had a smaller change in lightness (ΔL) than those in the regular toothpaste group. The whitening toothpaste group showed a greater change in lightness on average than those in the regular toothpaste group, with an increase in lightness as the number of brushstrokes increased. According to the roughness and abraded depth data, the whitening toothpaste group was least affected by brushing, while the reference and regular toothpaste groups showed higher levels of roughness and abraded depth at all intervals. (Am J Dent 2024;37:3-8).

 

 

 

 

 

 

Mail: Prof. Dr. Young-Seok Park, School of Dentistry, Seoul National University, 101 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea. E-mail: ayoayo7@snu.ac.kr

 

 

 

Effect of group and individual education on shade matching competency of dental students

 

Ivan S. Ristić, dds, ms, phd, Maria Gonzalez, dds, ms, Franklin Garcia-Godoy, dds, ms, phd, phd &  Rade D. Paravina, dds, ms, phd

 

Abstract: Purpose: To evaluate the influence of group and individual education on shade matching quality using a visual color competency test to match shade tab pairs from two Vita classical A1-D4 shade guides. Methods: 60 dental students, 21-25 years old (39 females, 21 males) participated in the study. All participants passed a color deficiency test before the experiment. The examination was voluntary and approved by the corresponding Ethics Committee. Students were randomly divided into three groups (n=20): one control group, NE (no education) and two experimental groups – GE (group education) and IE (individual education). The study was performed in three phases. In the “before” (B - Phase 1) and “after” (A - Phase 3) phase, all groups had to match 16 pairs of tabs from two Vita classical A1-D4 shade guides, with the shade designations hidden by custom letter markings. All tabs were mixed on a gray surface illuminated by color-correcting light. In Phase 2 (between B and A), GE had only group education, while IE received additional individual education and training. The control group did not participate in Phase 2. Means and standard deviations were calculated, and differences were compared using the one-way ANOVA, ANCOVA test, and Student t-test for dependent samples (α= 0.05). Results: The NE group matched 10.3 (3.2) and 10.4 (2.9) tab pairs in the before and after phases, respectively. Corresponding results for GE were 11.1 (2.2) and 14.4 (1.9) and 9.5 (3.6) and 15.0 (1.5) for IE, respectively. In Phase 1 (B), no statistically significant difference was recorded among the groups (P= 0.260). The experimental groups achieved a statistically significant improvement compared with the control group in Phase 3 (A) (P< 0.001). Both experimental groups achieved statistically significant improvement within the group after education, GE (P< 0.001) and IE (P< 0.001). Within the limitations of this study, it was concluded that both experimental groups had statistically significant progress in shade matching. The group that received individual education (IE) made statistically significant progress compared with the group that received group education (GE). No statistically significant difference was found in the results of the control group between Phase 1 and Phase 3 of the study. (Am J Dent 2024;37:9-12).

 

 

 

 

 

Mail: Dr. Rade D. Paravina, The University of Texas School of Dentistry at Houston, 7500 Cambridge St., Suite 5350, Houston, TX 77054, USA. E-mail: Rade.Paravina@uth.tmc.edu

 

 

 

Mechanical properties of ion-releasing restorative materials

 

Marija Lalovic, dmd, msc, Veljko Kolak, dmd, phd, Irena Melih, dmd, phd, Ana Nikitovic, dmd, phd,  Isaak Trajkovic, mscengtech, Milos Milosevic, mscMecheng, PhD, Djordje Pejanovic, dmd, phd  &  Dragana Pesic, dmd, phd  

 

Abstract: Purpose: To evaluate and compare the laboratory compressive strength (CS), flexural strength (FS), and diametral tensile strength (DTS) of Cention Forte and three bulk fill restorative materials. Methods: A total of 168 specimens were prepared following the manufacturers’ instructions and standards for testing CS, FS, and DTS. Mechanical properties of Cention Forte (LC-Cent) were compared to three commercial bulk-fill materials for posterior restorations: Fuji IX Extra (Fuji), Tetric PowerFill (TPF), and Equia Forte HT (Equia). The tests were performed 24 hours after storage in distilled water on a universal testing machine at a crosshead speed of 0.75 mm/minute. Strength values (MPa) were calculated and statistically analyzed by one-way ANOVA and Tukey’s post hoc test (P< 0.05). Results: Analysis showed significant differences between tested materials for CS, FS, and DTS (P= 0.0001). LC-Cent showed the highest mean value for FS (112.8 MPa) with a significant difference compared to Fuji and Equia. DTS (49.2 MPa) of LC-Cent was significantly higher than all tested materials. TPF showed the highest mean value (180 MPa) for CS but without significant difference compared to LC-Cent. (Am J Dent 2024;37:13-18).

 

 

Mail: Dr. Marija Lalovic, Faculty of Stomatology in Pancevo, University Business Academy in Novi Sad, Zarka Zrenjanina 179, Pancevo 26000, Serbia. E-mail:  marija.lalovic@sfp.rs

 

 

Effects of frequently consumed beverages by children on the surface roughness of compomers

 

Melek Belevcikli, dds  &  Ebru Hazar Bodrumlu, dds, phd

 

 

 

Abstract: Purpose: To evaluate and compare changes on the surface roughness of conventional and colored compomers used in pediatric dentistry caused by beverages frequently consumed by children. Methods: 176 conventional and colored compomer discs were prepared. The discs were divided into four equal subgroups and incubated in different beverages: distilled water, milk, fruit juice, and cola. The surface roughness of the samples was measured and recorded on Days 1, 7, 14, 21, and 28. The data obtained were statistically analyzed. Results: In distilled water and milk, the surface roughness of the conventional compomer was higher than the colored compomer after Day 7 (P< 0.05). In fruit juice and cola, the surface roughness of conventional and colored compomers was similar at all timepoints (P> 0.05). There was a significant difference between discs incubated in distilled water and milk, on Days 21 and 28 (P< 0.05). The colored compomer showed the highest roughness in cola on Day 1, whereas the conventional compomer showed the highest roughness in milk on Day 21. (Am J Dent 2024;37:19-23).

 

 

 

 

 

 

 

 

                Mail: Dr. Melek Belevcikli, Department of Pediatric Dentistry, Faculty of Dentistry, Zonguldak Bulent Ecevit University, Zonguldak, Turkey.  E-mail: mbelevcikli@hotmail.com

 

 

 

 

Effect of ultrasonic and sonic instrumentation on shear bond strength of resin composite to enamel: An in vitro study

 

Ruhsan Müdüroğlu Adıgüzel, dds, phd, Abdelrahman Mustafa, dds, phd, Bahar Füsun Oduncuoğlu, dds, phd, Merİç Yavuz Çolak, msc, phd, Ayşe Gülşahı, dds, phd  &  Neslİhan Arhun, dds, phd

 

Abstract: Purpose: To assess and compare the effects of sonic and ultrasonic instrumentation on shear bond strength (SBS) and investigate the influence of adhesive system application modes (etch&rinse/self-etch) on SBS. Methods: In this experimental study, 45 extracted sound human molars were selected. Mesial and distal surfaces of the teeth were abraded until 90 smooth enamel surfaces were obtained. Specimens were divided into two groups, with half (N= 45) conditioned in etch&rinse mode and the remaining (N= 45) in self-etch mode using Tetric N Bond Universal. Composite resin discs were produced on these surfaces by filling Teflon molds. All specimens were aged via thermocycling. Each group was further divided into three more groups (n= 15) according to the type of periodontal instrumentation (ultrasonic, sonic or none). SBS values were recorded and analyzed using two-way ANOVA. Fracture sites were examined under a stereomicroscope. Results: The type of periodontal instrumentation had no significant effect on SBS values, whether sonic, ultrasonic or their absence (P= 0.945). The type of adhesive system mode had a significant influence on the shear bond strength values. Etch&rinse groups had significantly higher shear bond strength values than self-etch groups (P< 0.001). (Am J Dent 2024;37:24-28).

 

 

Mail: Dr. Abdelrahman Mustafa, Department of Dentistry and Dental Surgery, College of Medicine and Health Sciences, An-Najah National University, Nablus, Palestine.  E-mail: a.mustafa@najah.edu

 

 

Marginal adaptation of two-step self-etch versus universal adhesives for Class V restorations: Effect of Er:YAG laser vs. bur prepared cavities

 

Putri Noerpuspita, dr med dent, Ivo Krejci, Emer Prof, dr med dent, pd  &  Tissiana Bortolotto, dr med dent, pd

 

Abstract: Purpose: To compare the in vitro effect of laser and bur preparation on marginal adaptation of Class V cavities restored with a 2-step self-etch and distinct universal one-component universal adhesives used in self-etching mode. Methods: 96 Class V cavities were prepared with conventional burs or with an Er:YAG laser. Four universal self-etch (Unibond Extra Low Shrinkage, All Bond Universal, SKB-100 and Prime&Bond active) and a 2-step self-etch adhesive (Clearfil SE Bond) that served as control were used to restore the cavities with direct composite. The percentages of continuous margins were evaluated by quantitative SEM analysis before and after a fatigue test consisting of 240,000 occlusal loads and 600 warm/cold thermal cycles. Results: The marginal adaptation of bur prepared restorations was statistically superior to laser-prepared ones. Class V cavities restored with Clearfil SE Bond and the one-component self-etching universal adhesives All Bond Universal and Prime&Bond active presented the highest and statistically similar percentages of continuous margins before and after loading under both bur and laser cavity preparation. The lowest percentages of continuous margins were observed in the groups restored with the low shrinking adhesive (Unibond ELS), with medians of 49 and 21 for bur and laser prepared cavities after loading. (Am J Dent 2023;37:29-34).

 

 

 

 

Mail: Dr. Tissiana Bortolotto, Division of Cariology and Endodontology, University Clinic of Dental Medicine, University of Geneva, Rue Michel-Servet 1, 1211, Geneva 4, Geneva, Switzerland. E-mail: Tissiana.Bortolotto@unige.ch

 

 

 

Effect of gutta-percha solvents on the push-out bond strength to root dentin of a syringe-mixed resin sealer and premixed bioceramic sealer

 

Zeti Adura Che Ab Aziz, bds, mclindent, Eshana Banerjee Nair, bds, Myrna Nurlatifah Zakaria, bds, mclindent, phd, Nora Sakina Mohd Noor, bds, mclindent  &  Noor Hayati Azami, bds, mclindent

 

Abstract: Purpose: To assess the push out bond strength (POBS) of a syringe-mixed resin sealer and a premixed bioceramic sealer to root dentin exposed to different gutta-percha (GP) solvents and to determine the mode of failure. Methods: A total of 200 horizontal root slices (1 mm thickness) were prepared up to size 40, 0.04 taper and randomly divided into four main groups based on solvent (Endosolv, orange oil, chloroform) and control (saline), then subdivided into two subgroups based on sealer type (AH Plus Jet and iRoot SP). Samples were exposed to respective solvents for 5 minutes and after the final rinsing, canal spaces were filled with either AH Plus Jet or iRoot SP. POBS test was performed 2 weeks after incubation and mode of failure following POBS test was evaluated. Data were analyzed using two-way ANOVA and Dunnett post hoc analysis (P< 0.05). Failure mode patterns were categorized as adhesive, cohesive and mixed failures. Results: There was no significant difference (P> 0.05) in POBS between all solvent groups against the control in both AH Plus Jet and iRoot SP groups. Regardless of the use of solvents, AH Plus Jet group had significantly higher bond strength (P< 0.001) compared to iRoot SP group. The predominant mode of failure was mixed failure in all groups irrespective of type of sealer and exposure to solvents. (Am J Dent 2024;37:35-38).

 

 

Mail: Dr. Noor Hayati Azami, Department of Restorative Dentistry, Faculty of Dentistry, University of Malaya, 50603 Kuala Lumpur, Malaysia.  E-mail:  nhayatiazami@um.edu.my

 

 

 

Activation of endodontic irrigants using a 9.3 µm CO₂ and diode lasers: A laboratory proof of concept model

 

Clara Isabel Anton y Otero,  dmd, Laurine Marger, phd,  Enrico Di Bella, phd, Marwa Abdelaziz, dmd, phd, Albert Feilzer, dmd, phd  &   Ivo Krejci, dmd, phd

 

Abstract: Purpose: To investigate the differences between irrigant propagation and temperature changes using laser-activated irrigation (LAI) at different settings in an artificial root canal model. Methods: Using an artificial resin root canal model, irrigant activation was achieved in 19 experimental groups with eight samples each. A 9,300 nm CO₂ laser, two diode lasers with different settings (wavelengths 455, 808, 970, and 980 nm) were compared to 2,940 nm Er:YAG laser and traditional needle irrigation. Er:YAG and CO₂ laser were activated in the pulpal chamber only, while diode lasers and needles were inserted into the main root canal. Lasers were activated for 5x 20 seconds resulting in 100 seconds of activation or rinsing for each sample. After each activation of 20 seconds, a photo was taken of the side canals and the propagation of the dye was measured with a digital measuring tool after calibration. Further, the temperature of the irrigant was reported after activation of 20 seconds and repeated 5 times. Data were checked for normality and statistically compared. Results: All lasers increased the irrigant propagation compared to conventional irrigation. Significant differences were found between groups regarding propagation and temperature (P< 0.0027). Er:YAG and CO₂ laser had similar effects on irrigant propagation in middle and apical located side-canals with specific power parameters and were superior to diode lasers and syringe irrigation. The irrigant’s temperature increased significantly with the diode and CO₂ lasers. (Am J Dent 2024;37:39-46).

 

 

 

 

 

 

 

 

Mail: Dr. Clara Isabel Anton y Otero, Division of Cariology and Endodontology, CUMD - University Clinics of Dental Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland. E-mail: clara.antonyotero@unige.ch

 

 

 

 

Microbial shift of oral biofilm associated with remineralization of root dentin lesions

 

Yuna Koura, dds,  Kiyoshi Tomiyama, dds, phd,  Yuichi Kunimatsu, dds, phd,  Nobushiro Hamada, dds, phd &  Yoshiharu Mukai, dds, phd

 

Abstract: Purpose: To examine the relationship between remineralization of incipient root dentin lesions and the presence of polymicrobial biofilms, as well as examine changes in microbial composition. Methods: Bovine root dentin disks used as specimens for biofilm formation, were cultured using saliva from a single donor. Amsterdam Active Attachment biofilm model was used to grow biofilms. The culture medium was McBain 2005 with 0.2% sucrose and 0.4 ppm F as sodium fluoride. After cultivation for 48 hours to achieve demineralization, a control group (n=10) was obtained and the other specimens were further cultured for 336 hours in two types of remineralization culture medium, with sucrose (S+) and without sucrose (S-), through continuous anaerobic incubation (10% CO₂,10% H₂, 80% N₂). Then half of the specimens cultured in the S- medium were transferred to the S+ medium for an additional 48 hours resulting in three experimental groups S(+) (n=10), S(-) (n=10), and S(-)de (n=10), respectively. Experiment 1: Transverse microradiography (TMR) analysis - Immediately after respective culture treatments, integrated mineral loss (IML) and lesion depth (LD) in the dentin specimens were analyzed by TMR. Experiment 2: Microbiome analysis - Sequence data of the 16S rRNA gene of each sample was obtained using MiSeq, and partial base sequences were determined. Next-generation sequencing was performed to determine the taxonomic groups of fungi present in the biofilm samples. Results: Experiment 1: In the control group, formation of dentin demineralization lesions by polymicrobial species biofilms was confirmed. The S(-) group showed significantly decreased IML and shallower LD compared to the control group. The S(-)de group showed a significant increase in IML and LD compared to the S(-) group. Experiment 2: There were statistically significant differences in microbiome between the control group and each of the three experimental groups, both at the genus and species levels. A significant difference in genus was observed between the S(-) group and the S(-)de group. (Am J Dent 2024;37:47-52).

 

 

Mail: Prof. Dr. Yoshiharu Mukai, Department of Restorative Dentistry, Kanagawa Dental University, 82 Inaokachō, Yokosuka, Kanagawa 238-8580, Japan. E-mail: mukai@kdu.ac.jp

 

 

Working viscosity and non-Newtonian behavior of silicone denture liners

 

Audrey M. Selecman, dds, mds,  Brian R. Morrow, ms,  Jane Moore, dmd, ms, phd &  Franklin Garcia-Godoy, dds, ms, phd, phd

 

Abstract: Purpose: To evaluate flow profile and non-Newtonian behavior of 10 different silicone lining materials. Methods: Ten commercially available silicone lining materials were selected for evaluation. The flow profile and non-Newtonian behavior of each material was measured using a shark fin testing method. Fin height and resultant base thickness were measured with a digital caliper and compared with one-way ANOVA and Student-Newman-Keuls post hoc test and fin base by Kruskal-Wallis one-way ANOVA on ranks with Dunn post hoc test with significance at P< 0.05 for both. Results: Shark fin heights ranged from 9.62 ± 0.86 mm [Reline II (Soft)] to 25.54 ± 0.43 mm [Sofreliner (Medium)]. Shark fin bases ranged from 2.57 ± 0.51 mm [Sofreliner (Medium)] to 10.31 ± 0.57 mm [Reline II (Soft)]. Statistically significant differences were found between certain samples’ shark fin heights as well as resultant bases (P< 0.05) indicating different rheological properties. (Am J Dent 2024;37:53-56).

 

 

 

 

Mail: Dr. Audrey M. Selecman, Department of Prosthodontics, College of Dentistry, University of Tennessee Health Science Center, 875 Union Avenue, Memphis, TN 38163, USA.  E-mail: aselecma@uthsc.edu