Showing papers in "Journal of Esthetic and Restorative Dentistry in 2018"

Depth of cure of bulk fill resin composites: A systematic review.

Abstract: OBJECTIVE To evaluate scientific evidence regarding depth of cure of bulk-fill resin composites (BFRCs) and related factors. MATERIAL AND METHODS PubMed/Medline, Embase, Scopus, and ISI Web of Science databases were accessed from October 2016 to May 2017. Investigations published in English language, assessing depth of cure of BFRCs by microhardness test and/or degree of conversion (DC) were included. Studies using exclusively ISO 4049, employing specimens deepness less than 4 mm, as well as those not reporting exposure time and/or irradiance from light curing units (LCUs) were excluded. RESULTS In total, 742 studies were found from which 33 were included. From 21 studies evaluating BFRCs microhardness, 10 showed acceptable bottom/top ratios (≥0.8) for all tested materials. However, material-dependent results and non-satisfactory bottom/top microhardness ratios (<0.8) were reported in 9 and 2 investigations, respectively. From 19 studies that assessed DC, 11 showed acceptable results (≥50%) for all tested BFRCs, while 8 studies reported material-dependent outcomes. Overall, irradiance from LCUs ranged from 650 to 1330 mW/cm2 and exposure time from 5 to 60 seconds. Favorable depth of cure results were observed with the use of LCUs emitting irradiance ≥1000 mW/cm2 and exposure times ≥20 seconds. CONCLUSIONS High depth of cure rates by BFRCs, depends on some factors as material, irradiance and exposure time. Polywave LCUs were useful but not essential on polymerizing alternative photoinitiator-containing BFRC. CLINICAL SIGNIFICANCE LED curing devices (polywave or monowave) displaying an irradiance ≥1000 mW/cm2 and 20 seconds of exposure time are imperative to accomplish successful polymerization of most BFRCs.

A literature review on the new polymer-infiltrated ceramic-network material (PICN).

Abstract: Objectives Ceramics and composites are the most used materials for dental application. Recently, the characteristics of both were combined on the called "polymer-infiltrated ceramic-network" (PICN). The aim of this review is to report the behavior of PICN, comparing the findings that may support the correct clinical application. Overview The PICN material is a structure with a sintered ceramic matrix infiltrated with a polymer matrix. Studies evaluated this material microstructure and composition, mechanical properties and adhesive behavior. The most cited mechanical properties are flexural strength, compressive strength, elastic modulus, Weibull modulus, hardness, fracture toughness and fatigue resistance. Most studies compared PICN with feldspathic porcelain, lithium disilicate glass-ceramic, lithium silicate, zirconia-reinforced glass-ceramic, leucite reinforced glass-ceramic, polycrystalline alumina and zirconia. Other studies evaluated a similar material (a nanoceramic resin). Clinical significance The mechanical properties of the PICN are equivalent to the properties of nanoceramic resins, lower to lithium disilicate glass ceramic and superior to feldspathic porcelain. Yet, the findings suggest a highly resistant material to degradation at low loads (close to physiological situation) when cemented on a substrate.

Assessment of marginal adaptation and fracture resistance of endocrown restorations utilizing different machinable blocks subjected to thermomechanical aging.

Abstract: Objective This in vitro study was conducted to assess the marginal adaptation and fracture resistance of computer aided design/computer aided manufacturer (CAD-CAM) fabricated endocrowns restoring endodontically treated molars using different machinable blocks with thermomechanical loading protocols. Materials and methods Devitalized mandibular molars were prepared in a standardized way and divided into 4 groups (n = 10) to receive CAD/CAM fabricated endocrowns using four materials (Lithium disilicate ceramics, polymer infiltrated ceramics, zirconia-reinforced lithium silicate ceramics and resin nanoceramics. Marginal gaps (µm) were measured using stereomicroscope before cementation and after cementation. After thermomechanical aging, marginal gap measurements were repeated, and then fracture resistance test was performed. Two-way analysis of variance (ANOVA) and Tukey HSD multiple comparisons were used to assess the effect of material on the marginal gap before, after cementation, and after thermomechanical aging. One Way ANOVA was used to assess the effect of material on the fracture resistance. Results The difference between marginal gaps values of the tested materials was statistically insignificant but with significant increase after cementation and after thermomechanical aging. Cerasmart endocrowns showed the highest mean fracture load value (1508.5 ± 421.7N) with statistically significant difference than Vita Enamic endocrowns and Celtra Duo. Conclusion The tested materials showed marginal vertical gap readings within the limits of clinically acceptable standards. Resin nanoceramics and lithium disilicate showed the highest values of fracture resistance followed by polymer infiltrated ceramics favoring their use for endocrown restorations. Clinical significance The mechanical behavior of ceramic materials varies with the variation of their structure and mechanical properties. Accordingly, further investigation is always needed to explore the biomechanical behavior of recent materials when used as endocrowns before clinical trials.

Evaluation of the effect scan pattern has on the trueness and precision of six intraoral digital impression systems.

Abstract: Objective Clinicians have been slow to adopt digital impression technologies due possibly to perceived technique sensitivities involved in data acquisition. This research has two aims: determine whether scan pattern and sequence affects the accuracy of the three-dimensional (3D) model created from this digital impression and to compare the 5 imaging systems with regards to their scanning accuracy for sextant impressions. Materials and methods Six digital intraoral impression systems were used to scan a typodont sextant with optical properties similar to natural teeth. The impressions were taken using five different scan patterns and the resulting digital models were overlayed on a master digital model to determine the accuracy of each scanner performing each scan pattern. Furthermore, regardless of scan pattern, each digital impression system was evaluated for accuracy to the other systems in this same manner. Results No differences of significance were noted in the accuracy of 3D models created using six distinct scan patterns with one exception involving the CEREC Omnicam. Planmeca Planscan was determined to be the truest scanner while 3Shape Trios was determined to be the most precise for sextant impression making. Conclusions Scan pattern does not significantly affect the accuracy of the resulting digital model for sextant scanning. Clinical significance Companies who make digital impression systems often recommend a scan pattern specific for their system. However, every clinical scanning scenario is different and may require a different approach. Knowing how important scan pattern is with regards to accuracy would be helpful for guiding a growing number of practitioners who are utilizing this technology.

Effect of tooth brushing on gloss retention and surface roughness of five bulk-fill resin composites.

Abstract: Objectives To determine the effects of tooth brushing on five bulk-fill resin based composites (RBCs). Method Ten samples of Filtek Supreme Enamel (control), Filtek One Bulk Fill, Tetric EvoCeram Bulk Fill, SonicFill 2, SDR flow+, and Admira Fusion X-tra were light cured for 20 seconds using the Valo Grand curing light. After 24 hours storage in air at 37°C, specimens were brushed in a random order using Colgate OpticWhite dentifrice and a soft toothbrush. Surface gloss was measured prior to brushing, after 5,000, 10,000 and 15,000 back and forth brushing cycles. Surface roughness was measured after 15,000 brushing cycles using atomic force microscopy (AFM) and selected scanning electron microscope (SEM) images were taken. The data was examined using ANOVA and pair-wise comparisons using Scheffe's post-hoc multiple comparison tests (α = 0.05). Results Surface gloss decreased and the surface roughness increased after brushing. Two-way ANOVA showed that both the RBC and the number of brushing cycles had a significant negative effect on the gloss. One-way ANOVA showed that the RBC had a significant effect on the roughness after 15,000 brushing cycles. For both gloss and roughness, brushing had the least effect on the nano-filled control and nano-filled bulk-fill RBC, and the greatest negative effect on Admira Fusion X-tra. The SEM images provided visual agreement. There was an excellent linear correlation (R2 = 0.98) between the logarithm of the gloss and roughness. Conclusion After brushing, the bulk-fill RBCs were all rougher than the control nano-filled RBC. The nano-filled bulk-fill RBC was the least affected by brushing. Clinical significance Bulk-fill RBCs lose their gloss faster and become rougher than the nanofilled conventional RBC, Filtek Supreme Ultra. The nanofilled bulk-fill RBC was the least affected by tooth brushing.

Longevity of ceramic onlays: A systematic review.

Abstract: OBJECTIVE: This systematic review aimed to evaluate the longevity of ceramic onlays and identify the factors that influence their survival. MATERIALS AND METHODS: An electronic search was conducted through PubMed (MEDLINE), Google Scholar and Cochrane Library, up to August 2017. The literature search aimed to retrieve all the clinical studies on the longevity of ceramic onlays. Ceramic onlay was defined as any partial ceramic restoration that covers at least one cusp. RESULTS: A total of 21 studies met the selection criteria and were deemed suitable for this review. The medium‐term studies (2–5 years) indicated a survival rate of 91‐100%, and the long term studies (more than 5 years) showed a survival rate of 71–98.5%. The most common reason of failure was fracture, followed by debonding and caries. The most common patterns of deterioration were loss of margin integrity and discoloration. Onlay longevity can be enhanced if the preparation allows for at least 2 mm occlusal ceramic thickness and incorporates additional retentive features. Restoring teeth that are nonvital, teeth in a more posterior region, or teeth for patients with parafunctional habits appears to be associated with greater ceramic failure. Fabrication materials and methods, and adhesive bonding system did not seem to influence onlay longevity. CONCLUSIONS: The clinical performance of the ceramic onlay appears acceptable regardless of the follow‐up duration. Fracture of the ceramic onlay is the predominant cause of failure, and the most observed form of deterioration was associated with the restoration margin. CLINICAL SIGNIFICANCE: Ceramic onlay appears to be a reliable option to restore posterior teeth. The most common pattern of failure is fracture of the ceramic material. The risk of ceramic onlay failure seems to increase if the restored tooth is nonvital and the patient demonstrates parafunctional habits.

Effect of staining beverages on color and translucency of CAD/CAM composites.

Abstract: This study investigated the color (ΔE) and translucency changes (ΔTP) of CAD/CAM composites after exposure to staining solutions using both spectrophotometer and shade-matching device. Direct (Filtek Z350XT [ZT]), indirect (Shofu Ceramage [CE]) and CAD/CAM (Shofu HC Block [HC], Lava Ultimate [LU], Vita Enamic [EN]) composite specimens measuring 12 × 14 × 1.5 mm were fabricated, divided into five groups (n = 8), and immersed in cola, tea, coffee, red wine, distilled water (control) at 37°C for 7 days. Color parameters were determined with both spectrophotometer and shade-taking device at baseline and 1 week. Delta E (ΔE) with white and black backgrounds, and Delta TP (ΔTP) were computed. Statistical testing was performed with ANOVA and Tukey post hoc test (P 3.3) were observed for almost all materials when exposed to wine, coffee and tea. Direct, indirect, and CAD/CAM composites are all susceptible to various degrees of discoloration and translucency changes after exposure to staining beverages. Red wine caused the most discoloration and translucency changes. Limitations of these materials must be considered when placing an aesthetic restoration. Clinical significance Direct, indirect, and CAD/CAM composites are all susceptible to various degrees of discoloration and translucency changes after exposure to staining beverages. Red wine generally caused the most discoloration and translucency changes. Although CAD/CAM composites were more color stable than direct and indirect materials when exposed to red wine, color changes were still clinically perceptible.

Optical properties of contemporary monolithic CAD-CAM restorative materials at different thicknesses.

Abstract: Objective This study evaluated the optical properties of contemporary monolithic CAD-CAM materials with different chemical compositions. Materials and methods Totally, 210 rectangular-shaped, A2 shade specimens (12 × 14 mm) were fabricated from VITA Suprinity T, VITA Enamic T, VITA Mark II, GC Cerasmart LT, Lava Ultimate LT, IPS e.max CAD LT and Prettau Anterior blocks and polished to thicknesses of 0.5 ± 0.01 and 1.0 ± 0.01 mm (n = 15 each material). A dental spectrophotometer (VITA Easyshade Compact) was used to calculate the translucency parameter (TP) and opalescence parameter (OP) values of all tested materials. Statistical analysis was performed using one-way analysis of variance, multiple comparison Tukey's test and independent samples t-test (P = .05). Results In the 0.5-mm thickness group, GC Cerasmart and Prettau Anterior had the highest and lowest translucency values, respectively. VITA Suprinity had the highest OP value, whereas VITA Mark II and Prettau Anterior had the lowest OP values. In the 1.0-mm thickness group, GC Cerasmart and Lava Ultimate had the highest translucency, whereas Prettau Anterior had the lowest translucency. VITA Suprinity and Prettau Anterior had the highest and lowest OP values, respectively. Conclusions The optical properties of monolithic restorative materials were influenced by the type and thickness of the material used. Clinical significance According to the results of this study, monolithic materials with different chemical compositions have revealed different optical properties. To obtain esthetic restorations and provide shade matching with natural dentition especially for anterior teeth, monolithic materials should be carefully chosen.

Color of bulk-fill composite resin restorative materials.

Abstract: Objective To evaluate the color stability of novel bulk-fill composite resins. Materials and Methods Color measurements of a nanohybrid composite resin (Z550) and 3 bulk-fill composite resins (BLK, AFX, XTF; n = 45) were performed before polymerization. After polymerization, color measurements were repeated and specimens were immersed in distilled water or red wine, or coffee. Color change [CIEDE2000 (ΔE00)] was calculated after 24 h, 1 and 3 weeks. Data were analyzed with Kruskal-Wallis, Mann-Whitney U and Wilcoxon tests (α = 0.05). Results Color changes observed after polymerization were significant for all groups. Color changes observed in distilled water for Z550 and AFX were significant. Color changes after stored in red wine and coffee were significant for all groups. Bulk-fill composite resin color change increased over time for all groups in red wine and coffee (P < .05). Conclusion Polymerization significantly changed the color of nanohybrid composite resin and bulk-fill composite resins. AFX had the highest color change in distilled water. The color of tested bulk-fill composite resins significantly changed after immersion in beverages and over time. Color change observed with the nanohybrid composite resin after 1 week was stable. CLINICAL SIGNIFICANCE Clinicians should keep in mind that tested composite resins may change color when exposed to water and significantly change color immediately after they are polymerized. In addition, the color change continues over time should the patient is a coffee and/or red wine consumer.

Interventions for dental fluorosis: A systematic review.

Abstract: OBJECTIVE Dental fluorosis has considerable implications on the patients' quality of life The present study assesses the comparative effectiveness of the various interventions for the treatment of fluorosed enamel MATERIALS AND METHODS Nine databases were searched from inception to December 2016 for randomized trials After duplicate study selection, data extraction, and risk of bias assessment, mean differences (MD) or Relative Risks and the corresponding 95% confidence intervals (CIs) were calculated and assessed with the GRADE approach RESULTS Six trials with a total of 348 patients (at least 40% male/60% female) with a mean age of 177 years treated with bleaching, microabrasion, or resin infiltration were included Evidence of low quality indicated that microabrasion resulted in smaller esthetic improvement compared to bleaching (MD = -29; 95% CI = -34 to -25) Evidence of moderate quality indicated that compared to bleaching a greater esthetic improvement was seen with resin infiltration (MD = 36; 95% CI = 27-46) or a combination of bleaching with resin infiltration (MD = 35; 28-37) However, all comparisons were supported from single trials and therefore caution is warranted CONCLUSIONS Based on the existing limited evidence, resin infiltration seems to be the most promising treatment for dental fluorosis, followed by bleaching and microabrasion CLINICAL SIGNIFICANCE For this systematic review, which was registered beforehand in PROSPERO (CRD42016053492), we synthesized evidence from existing randomized clinical trals on humans to see which treatment is most effective for the esthetic rehabilitation of dental fluorosis, the prevalence of which is seeing a worldwide steady increase We found that resin infiltration seems to be the most effective treatment approach for lesions of mild to moderate severity, followed by bleaching, and finally microabrasion Our study's strengths are its a priori registration, wide search, quality check according to Cochrane guidelines, and the use of a new robust analytic method to provide valid clinical recommendations according to the principles of evidence-based medicine

Lip repositioning for the treatment of excess gingival display: A systematic review.

Abstract: Background Lip repositioning is a conservative surgical technique used to treat excess gingival display. An array of modifications has been introduced to the technique over time and as studies show the technique and its modifications to be successful, there is little standardized information for clinicians to make informed decisions when choosing this technique for the treatment of patients with excessive gingival display (EGD). Objectives To review the current literature on the topic of lip repositioning for the treatment of excessive EGD, exploring outcome, and result longevity. Methods A structured systematic search was carried out using the Ovid database and Web of Science to identify published studies on lip repositioning technique. Search was restricted to studies in the English language, describing a surgical intervention. Case reports were included as the number of published studies was limited. Results The electronic search identified 93 articles, hand search identified 1 article, and reference search identified 1 article. After excluding duplicates and screening articles, a total of 22 articles met the inclusion criteria. An estimated mean improvement of 3.4 mm (95% confidence interval, 3.0-3.8 mm) was found possible with lip repositioning. Data analysis was performed using only 4 studies, amounting to a total of 33 patients. Potential risk of bias was identified in some of the studies included. Conclusions Despite the limited available studies on lip repositioning, an estimated mean improvement of 3.4 mm was found to be possible with surgical lip repositioning, suggesting that the technique could be used successfully to treat EGD. However, more studies are necessary to properly evaluate the treatment approach and stability of the technique. Clinical significance Recently, the demand for esthetics has significantly increased, driven by increased patient awareness and the search for an ideal smile. Creating the perfect smile is an intricate process that requires a multidisciplinary approach, with careful consideration of the lips and the gingival outline. Excess gingival display results in an unaesthetic smile, lip repositioning offers a comparatively simple solution for this problem. While the quality literature on this topic is limited statistical analysis of collected studies show that an estimated mean improvement of 3.4 mm can be achieved with surgical lip repositioning.

Perception of facial, dental, and smile esthetics by dental students

Abstract: OBJECTIVE To comprehensively assess dental students' perception of facial, dental and smile esthetics and to assess whether such a perception varies by gender, clinical training, and Grade Point Average (GPA). MATERIALS AND METHODS Series of photographs were digitally manipulated involving three facial, two smile, four dental, and one gingival components. Students in preclinical and clinical levels evaluated the original and manipulated images using a visual analogue scale scored from 1 to 5 where 5 is the standard image and 1 is the least pleasant one. The responses were then analyzed using Mann-Whitney test. A P value of < .05 was considered significant. RESULTS Four hundred and eight dental students participated in this study. With regard to the overall esthetics, males and clinical students scored higher than females and preclinical students, respectively, did. With regard to the individual esthetic components, males had significantly higher scores in buccal corridors, midline shift, clinical crown width, and gingival marginal height, while females had significantly higher score in median diastema (P < .05). Clinical students had a better perception of facial asymmetry, gingival display, buccal corridors, and clinical crown width compared to the preclinical students. Effect of GPA was minimal and even contradictory; students with lower GPA had a better perception of midline deviation and occlusal canting than those with higher GPA scores. CONCLUSIONS Male dental students, and unexpectedly unlike females, have a better perception of facial and dental esthetics. Unlike GPA, whose effect was minimal, clinical training has a substantial positive effect on the assessment of beauty. CLINICAL SIGNIFICANCE Appropriate perception of facial, dental and smile esthetics by dental students is of paramount importance for providing adequate dental services and for improving and polishing their professionalism.© 2018 Wiley Periodicals, Inc.

Influence of composite type and light irradiance on color stability after immersion in different beverages.

Abstract: Objective The aim of this study was to evaluate the color stability of two resin-based composites photo-activated by two light curing units (LCU) with different irradiances. Materials and methods Hundred disc-shaped specimens (2-mm thick) of a nanofilled (FZ- FiltekTM Z350 XT, 3M ESPE) and a microhybrid (ED-Empress® Direct, Ivoclar Vivadent) composites were photo-activated with two LCU: Valo® Cordless, Ultradent (VA-1800 mW/cm2 ) or Radii-cal, SDI (RA-900 mW/cm2 ). Samples (n = 5) were immersed during 12 days in distilled water (WT), orange juice (OJ), red wine (RW), coffee (CF), or Brazilian tea (BT). CIELAB coordinates were obtained using a spectrophotometer (Easyshade 4.0, Vita Zahnfabrik) before (T0 ) and after (T1 ) immersion. CIEDE2000 color difference (ΔE00 ) and whiteness index for dentistry (WID ) were calculated. Data was analyzed by two-way ANOVA and Tukey's test (α = 0.05%). Results FZ light-activated by VA showed higher L* and WID values (T0 ) and lower ΔE00 values after immersion in WT, OJ, and RW. However, there was no effect of both factors on ΔE00 when samples were immersed in BT and CF. ED light-activated by RA showed significant higher C* values (p ≤ .05). Conclusions The nanofilled composite photo-activated with higher irradiance showed greater L* and WID values and better color stability. However, all samples immersed in colored beverages showed ΔE00 values above the acceptability threshold. Clinical significance Initial color of resin-based composites can change after immersion in staining beverages. However, the best color stability was obtained by the nanocomposite photo-activated by a light-curing unit of higher irradiance.

Influence of cleaning methods on resin bonding to saliva-contaminated zirconia.

Abstract: Objective The aim of this study was to investigate the influence of different cleaning methods on the shear bond strengths of 2 resin cements to saliva-contaminated zirconia. Methods After saliva contamination, alumina-blasted zirconia specimens were cleaned with 1 of 5 methods of water-rinsing (SA), K-etchant GEL phosphoric acid (PA), Ivoclean (IC), AD Gel (ADG), or additional alumina-blasting (AB). Alumina-blasted zirconia without saliva contamination was used as control group (Cont). Composite cylinders were bonded to the zirconia with 1 of 2 dual-cured resin cements. The bond strengths were measured by shear testing after 24 hours (TC0) and after thermal cycling at 4°C-60°C (TC10 000) and specimen surfaces were evaluated using X-ray photoelectron spectroscopy (XPS). Data were statistically analyzed using 3-way analysis of variance and Tukey test (α = 0.05). Results There were no significant differences in the bond strengths of 2 resin cements between the Cont ADG, and AB groups before and after TCs (P > .05). SA, PA, and IC groups did not exhibit durable resin bonding to zirconia. XPS showed that carbon and nitrogen increased in the SA group in comparison to the Cont group. The concentration of carbon in other 4 groups returned to the concentration range of the Cont group; however, nitrogen was not detected in the only AB group. Conclusions Saliva contamination significantly reduced the bond strength of 2 resin cements to zirconia. Additional AB or cleaning with ADG resulted in effective cleaning of saliva contamination and preserved resin cement bond strength to zirconia. Clinical significance Saliva contamination occurs during clinical procedures for adjustment of zirconia ceramic restorations in the oral environment. AD Gel application is effective for removing saliva contaminants on the alumina-blasted zirconia surface beforehand by the dental laboratory instead of additional AB since AD Gel application and AB had a similar effect on the removal of organic components of saliva.

Effects of different etching modes on the nanoleakage of universal adhesives: A systematic review and meta-analysis.

Abstract: Purpose The aim of this systematic review was to evaluate how etching modes affect the nanoleakage of universal adhesive from in vitro studies. Materials and methods PubMed/MEDLINE, Web of Science, Scopus and Science Direct electronic databases were searched for in vitro studies that evaluated the nanoleakage of universal adhesives. A total of 511 (after duplicate removal) potentially relevant records were identified in the literature search. The titles and abstracts of the retrieved studies were screened by two independent researchers according to the main concept. Subsequently, the full text of potentially relevant studies was screened using the exclusion criteria. Thirteen studies were subjected to qualitative analysis, and 5 of them were selected for a detailed meta-analysis. Results Seven universal adhesives were evaluated in this review. The meta-analysis demonstrated that the etch-and-rinse technique significantly reduced the nanoleakage of the Peak Universal and G-Bond Plus adhesives, whereas the self-etch mode reduced the nanoleakage of All-Bond Universal. In comparison, the etching technique did not significantly alter the nanoleakage of either Prime&Bond Elect or Scotchbond Universal which was characterized by the smallest nanoleakage. Conclusions Etching modes significantly, in various ways, influence the nanoleakage of universal adhesives. Clinical significance Contrary to the drive to simplify bonding technologies, an appreciation of their adhesive components and how these perform according to bonding technique could yield a knowledge-based practical approach that ultimately improves the longevity of direct composite restorations.

Modification of glass ionomer cements on their physical-mechanical and antimicrobial properties.

Abstract: Objective The aim of this review was to provide an insight about the factors affecting the properties of glass ionomer cements and provides a review regarding studies that are related to modification of glass ionomer cements to improve their properties, particularly on physical-mechanical and antimicrobial activity. Methods PubMed and Science Direct were searched for papers published between the years 1974 and 2018. The search was restricted to articles written in English related to modification of glass ionomer cements. Only articles published in peer-reviewed journals were included. The search included literature reviews, in vitro, and in vivo studies. Articles written in other languages, without available abstracts and those related to other field were excluded. About 198 peer-review articles in the English language were reviewed. Conclusion Based on the finding, most of the modification has improved physical-mechanical properties of glass ionomer cements. Recently, researchers have attempted to improve their antimicrobial properties. However, the attempts were reported to compromise the physical-mechanical properties of modified glass ionomer cements. Clinical significance As the modification of glass ionomer cement with different material improved the physical-mechanical and antimicrobial properties, it could be used as restorative material for wider application in dentistry.

Surface changes of various bulk-fill resin-based composites after exposure to different food-simulating liquid and beverages.

Abstract: OBJECTIVE To evaluate surface roughness, hardness, and morphology changes of various bulk-fill resin composites eroded by different food-simulating liquids and beverages. MATERIALS AND METHODS One hundred and thirteen specimens were fabricated in polytetrafluoroethylene cylindrical mold (10 mm in diameter and 4 mm in thickness). Before immersion, baseline data of roughness, Vicker's microhardness were recorded and surface characteristics were examined using scanning electron microscopy (SEM). Each product of specimens (SDR, Dentsply; SonicFill, Kerr; Tetric N-Ceram Bulk Fill, Ivoclar Vivadent AG; and Filtek Bulk Fill, 3M ESPE) were divided into 5 groups for spicy and sour soup, spicy soup (Tom Yum), pineapple juice, passionfruit juice, and deionized water (served as a control). Specimens were then alternately immersed in storage agents for 5 seconds and artificial saliva for 5 seconds over 10 cycles. Specimens were stored in artificial saliva for 22 hours. This process was repeated for 28 days. After immersion, surface hardness and roughness of specimens were evaluated at 7, 14, 21, and 28 days and data were analyzed by two-way repeated ANOVA and Tukey's HSD (α = 0.05). Surface morphology of specimens was also examined on day 28. RESULTS The SDR group had the most statistically significant decrement in hardness (25.65 ± 1.74 kg/mm2 in mean difference) and increment in roughness (0.26 ± 0.10 μm in mean difference; P < .05). Passionfruit juice caused the most surface changes in bulk-fill resin composites. SEM photomicrographs showed surface changes of all resin composites in varying degrees. CONCLUSION Acidic food-simulating liquids and beverages significantly increased the surface roughness and decreased surface microhardness of bulk-fill resin composites after evaluation at the end of the 28-day immersion period. CLINICAL SIGNIFICANCE For restoration of the affected teeth in patients who consume acidic food and beverages, roughness and erosion of resin composites should be considered. All of bulk-fill resin-based composites except SDR may be suitable for restorations in these patients.

Protocol for a new concept of no-prep ultrathin ceramic veneers.

Abstract: Objectives No-prep veneers, although ideally considered the best option because of tooth structure maximum preservation, have been frequently criticized for some potential limitations including esthetic outcomes and periodontal complications. Clinical considerations A new protocol to optimize no-prep veneers restorations is presented. A key point of the proposed technique is to identify optimal margins’ positions: margin is positioned in the point of maximum convexity of teeth, avoiding the over contouring of traditional no-prep veneers. Conclusion The procedure can be appreciated for the marginal accuracy and the resulting aesthetic stability. The case reports show that properly managed no-prep veneers can have biologically healthy and aesthetically pleasant tooth-restoration transitions and emergence profiles. Clinical Significance High-quality no-prep veneers can be more challenging to realize than conventional veneers and the success seems to depend on a combination of good case selection, margins’ position, sound adhesive principles, clinical, and laboratory experience.

Fluorescence of natural teeth and restorative materials, methods for analysis and quantification: A literature review.

Abstract: Objective This review integrates published scientific information about the fluorescence of natural teeth, dental resins and ceramics, and the main methods of analysis and quantification presented in the literature. Overview Fluorescence is an emission of light (photons) by a substance that has absorbed light of higher energy. In natural teeth, it is more intense in the dentin than in the enamel and presents a bluish-white color. In dental resins and ceramics, fluorescence is obtained by the incorporation of materials that contain rare-earth luminescence centers (more precisely lanthanide luminescence centers), which allows these artificial materials to simulate natural teeth in a more beautiful and vital-looking way. However, the lack of knowledge about this optical phenomenon on the part of professionals indicates the need for more scientific studies and dissemination on this topic. Conclusions Aesthetic materials have variable spectral compositions and fluorescence intensities, which are not always compatible with natural teeth. The fluorescence of teeth and restorative materials can be influenced by several factors, such as aging, temperature, and bleaching. Several devices for fluorescence evaluation and quantification are used in studies under different methodologies, but the small number of studies on the subject make it difficult to compare their results. Clinical significance Fluorescence is a fundamental optical property for aesthetic rehabilitations since its presence and intensity in the restorative materials allows achieving an aesthetic result much closer to reality. However, the fluorescent behavior of natural teeth and aesthetic restorative materials is not yet fully understood by researchers and clinicians. Greater understanding of this phenomenon will contribute to the selection, indication, and clinical use of these materials.

Color difference thresholds for computer‐simulated human Gingiva

Abstract: OBJECTIVE To determine 50:50% perceptibility threshold (PT) and 50:50% acceptability threshold (AT) for computer-simulated samples of human gingiva using CIEDE2000 and CIELAB color difference formulas. MATERIALS AND METHODS Each of the 60 pairs of simulated human gingiva was displayed on a calibrated monitor, together with three pairs of upper central incisors of different lightness. The color of gingiva left and right from the midline was compared. A total of 30 observers (15 dentists, 15 laypersons) participated in the study. CIEDE2000 and CIELAB formulas were used to calculate the thresholds and a Takagi-Sugeno-Kang Fuzzy Approximation model was used as fitting procedure. Paired t-test (α = 0.05) was used in evaluation of statistical significance of differences. RESULTS The PT and AT for CIEDE2000 and 95% confidence intervals were 1.1 [0.4, 1.7] and 2.8 [1.8, 4.0], respectively. Corresponding CIELAB values were 1.7 [0.2, 2.6] and 3.7 [2.1, 5.7]. Significant differences (P < .01) were recorded between PT and AT, between the corresponding threshold values in CIEDE2000 and CIELAB formulas as well as between dentists and laypersons. CONCLUSIONS The difference between the perceptibility and acceptability threshold for gingiva was statistically significant in both CIEDE2000 and CIELAB. The same was true for differences between the corresponding thresholds using two color difference formulas, and between dentists and laypersons. Visual thresholds of human gingiva were not dependent upon lightness of adjacent teeth. Overall, CIEDE2000 color difference formula provided better fit than CIELAB formula in the evaluation of color difference thresholds of human gingiva. CLINICAL SIGNIFICANCE The data on visual thresholds for healthy human gingiva can be used as quality control tool/guide for selection and evaluation of dental materials, interpretation of color-related findings in clinical dentistry and research, and for standardization in dentistry. It is of particular value that this study was designed based on in-vivo color evaluation of healthy keratinized gingiva of subjects of different ethnicities, age groups, and gender.

In-office bleaching efficacy on stain removal from CAD/CAM and direct resin composite materials.

Abstract: Objective To evaluate the efficacy of in-office bleaching on stain removal from stained resin composite and ceramic computer-assisted design/computer-assisted manufacturing (CAD/CAM) blocks and direct resin composites. Methods Forty disk-shaped samples were fabricated from each of nine materials: six CAD/CAM (VITABLOCS Mark II, Paradigm MZ100, Exp Vita Hybrid Ceramic, VITA ENAMIC, Exp Kerr, and LAVA Ultimate) and three direct resin composites (Filtek Supreme, Venus Diamond, and Filtek Silorane). Samples were randomly divided into five groups (n = 8), each stained with a particular staining solution. Using a calibrated spectrophotometer and a black background, L*a*b* values were assessed before and after 120 days of staining. Samples were subjected to in-office bleaching using 40% hydrogen peroxide gel for one hour. At subsequent assessment, color change (ΔE) was calculated as the difference between L*a*b* values. Both ANOVA and the Duncan test were used to identify differences between groups (α = 0.05). Results Bleaching resulted in significant differences in ΔE values for all materials (P < .001). Bleaching efficacy was highly influenced by material composition and staining solution. Residual color values after bleaching for ceramic and hybrid ceramics ranged from −0.49 to 2.35, within the clinically acceptable maximum of 3.3. Values after bleaching for resin-based CAD/CAM ranged from −0.7 to 7.08 while direct resin composites values ranged from −1.47 to 25.13. Coffee left the greatest residual color on all materials. Conclusions Based on material nature, 40% hydrogen peroxide bleaching can remove staining. The new resin-based CAD/CAM blocks showed promising results in terms of color stability. Clinical Significance Bleaching using 40% hydrogen peroxide can be an effective method to remove stains from dental restorations. In this way, restoration replacement as a result of discoloration may no longer be necessary.

Esthetics and smile‐related characteristics assessed by laypersons

Abstract: Purpose This study aimed to identify the characteristics of full-smile images assessed by laypersons using visual analog scale measurement. Materials and methods A total of 176 young Chinese subjects (88 males and 88 females; 20-35 years of age) with healthy dentogingival tissue were recruited to have their dynamic smiles captured using digital technology. A full-smile frame image of each subject was selected and evaluated by 22 laypersons (11 males and 11 females; 20-35 years of age) using visual analog scale measurement. Unattractive and attractive groups were designated according to the 25th percentile and 75th percentile of average visual analog scale score for the subjects, respectively. Eight smile variables were used to measure the characteristics of the full-smile images. Pearson's Chi-square test and unpaired t tests were used to analyze the data with significance level α = 0.05. Results The visual analog scale measurement scores of unattractive and attractive subgroups, respectively, were 37.89 ± 2.12 and 50.67 ± 2.75 (male subjects), and 37.14 ± 2.80 and 51.92 ± 1.99 (female subjects). VAS scores were significantly different between subgroups for both male and female subjects (P .05). Conclusions Attractive full-smiles in young Chinese subjects demonstrated higher frequencies of average or low anterior smile line, average or low posterior smile line, upward upper lip curvature, and "broad and short" smile with high smile index. Clinical significance The smile variables of anterior smile line, posterior smile line, upper lip curvature, and smile index are predominant factors of smile attractiveness, which should be given priority to consider and manage in the anterior esthetic treatment plan.

Laser‐assisted removal of all ceramic fixed dental prostheses: A comprehensive review

Abstract: Objective The aim of this comprehensive review was to assess the effectiveness of erbium lasers in the removal of all ceramic fixed dental prostheses (FDPs). Overview Indexed databases were searched without language or time restriction up to and including December 2017 using different combinations of the following keywords: "lasers"; "phototherapy"; "crowns"; "prostheses and implants"; "inlays"; "ceramics"; "dental porcelain"; "zirconium"; "removal"; "debonding"; "fixed dental prostheses"; "veneers"; "laminates"; and "fixed bridge." All levels of available evidence including experimental studies, case reports and case series were included. Six clinical studies reporting a total of 13 cases and 6 experimental studies were included. Results from all studies showed that erbium lasers are effective reducing the shear bond strengths of all ceramic FDPs, in terms of easy removal of the restorations with none or minimal damage to teeth or ceramic surfaces. Conclusion Laser-assisted removal of all ceramic FDPs is a promising treatment protocol. Further well-designed controlled clinical trials and longitudinal prospective studies are needed to determine the precise laser parameters and duration of irradiation that could be used for removal of ceramic restorations with varying thicknesses. Clinical significance Benefits of lasers over mechanical instrumentation for crown removal encompass efficient restoration retrievability without restoration or teeth surfaces damages; and relatively easier and time effective procedure with no prerequisite for anesthetic agents. It is however imperative for clinicians to be well-trained and exhibit adequate knowledge regarding recommended power settings and laser-safety parameters with reference to interactions between light and different tissues and ceramics.

Digital workflow in full-arch implant rehabilitation with segmented minimally veneered monolithic zirconia fixed dental prostheses: 2-year clinical follow-up.

Abstract: Objective To illustrate a digital workflow in full-arch implant rehabilitation with minimally veneered monolithic zirconia and to report the outcomes including technical complications. Clinical considerations Three patients (5 edentulous arches) received full-arch fixed implant rehabilitation with monolithic zirconia and mild facial porcelain veneering involving a digital workflow. The incisal edges and occluding surface areas were milled out of monolithic zirconia to reduce the possibility of chipping. Porcelain veneering was applied on the facial aspect to improve the esthetic result. Outcomes and technical complications are reported after 2 years of clinical and radiographic follow-up. Conclusion Implant and prosthesis survival rates were 100% after a short-term follow-up of 2 years. Technical complications were encountered in one patient. They did not adversely affect prosthesis survival or patient satisfaction and were easily addressed. A digital workflow for the design and fabrication of full-arch monolithic zirconia implant fixed implant prostheses has benefits, but caution is necessary during CAD planning of the prosthesis to ensure a successful outcome. Long-term clinical studies are needed to corroborate the findings discussed in this report. Clinical significance This article presents an integrated digital workflow that was implemented for the implant-prosthodontic rehabilitation of three edentulous patients with monolithic zirconia prostheses. Monolithic zirconia has been successfully incorporated in implant prosthodontics in an effort to reduce the technical complications associated with bilayered ceramics. This workflow simplifies design and fabrication of the zirconia prostheses. However, caution should be taken during CAD planning of the prosthesis to make sure the zirconia cylinder is sufficiently thick at the interface with the titanium insert. Additionally, when cutback is planned for facial porcelain veneering, the functional occluding cusps and incisal edges should be fabricated in monolithic zirconia to avoid chipping.

A comparison between modified and conventional surgical techniques for surgical lip repositioning in the management of the gummy smile.

Abstract: Aim The aim of this study was to evaluate and compare conventional and modified lip repositioning surgical techniques used for management of gummy smile involving hyperactive lip elevator muscles. Methods and materials A prospective study was conducted between April 2016 and May 2017. Twenty two adult patients aged 18-38 years with gummy smile ranging from 4 to 6 mm because of soft tissue disorders were included in the study. All patients were treated in the oral and maxillofacial department at Damascus University. The sample was divided into two groups of 11 patients. The first group was treated by the conventional standard technique, and the second group treated by a modified study technique. The amount of gingival display in full smile was evaluated in both groups following each intervention. Results Both groups exhibited a statistically significant reduction in the measurement of gummy smile at month 1 and 6 postoperatively (P .05). The recent study showed a significant difference in gingival display between 3 and 6 months postoperatively in group 1, but no significant difference in group 2. Conclusion This study showed that the modified technique utilized in treating gummy smile has less relapse after surgery, shows excellent cosmesis and compared to the conventional technique, greater sustainability. Clinical significance The recent increase in demand for an esthetic smile has led to the development a modification of conventional lip repositioning for correcting gummy smile by myotomy of lip elevator muscles. This modified technique offers less relapse and greater stability post-operatively than the conventional technique.

The digitally replicated denture technique: A case report.

Abstract: Objective Conventional complete denture protocols require several patient appointments with multiple laboratory procedures. There are multiple workflows incorporating digital technology that can expedite the process, whereas increasing predictability. The proposed digitally replicated denture technique (DRDT) demonstrates a predictable workflow for fabricating complete dentures for patients with existing dentures. Clinical procedure A patient's existing maxillary and mandibular complete dentures were scanned with an intraoral scanner. The generated STL was then printed using a desktop 3D printer. This served as a custom tray and record base to decrease patient chair time and associated laboratory procedures. Conclusion The DRDT workflow incorporates digital technology into a complete denture protocol to minimize laboratory steps and chair time when fabricating complete dentures for patients with existing prostheses. Clinical significance The use of a digitally replicated denture using rapid prototyping can streamline the process of complete denture fabrication for patients with existing dentures.

Treatment of multiple maxillary adjacent class I and II gingival recessions with modified coronally advanced tunnel and a new xenogeneic acellular dermal matrix.

Abstract: Objective To evaluate the treatment of maxillary Miller Class I and II multiple adjacent gingival recessions using the modified coronally advanced tunnel technique (MCAT) combined with a new porcine acellular dermal matrix (PADM). Materials and Methods Twelve patients exhibiting at least six adjacent maxillary Miller Class I and II gingival recessions were consecutively treated by means of MCAT and a PADM. Recession depth (RD), recession width (RW), probing pocket depth (PD), keratinized tissue height (KT), clinical attachment level (CAL), mean root coverage (RC), and complete root coverage (CRC) were recorded. Results At 12 months, CRC was obtained in 43% of the 100 gingival recessions, while the mean RC measured 84.35%. Mean RD reduction was 3.16 ± 0.75 mm (P < 0.001), mean RW reduction was 1.73 ± 0.65 mm (P < 0.001), while the gain of CAL was 3.26 ± 1.33 mm (P < 0.001). All patients were satisfied with the esthetic appearance and would undergo the same surgery again. Conclusion Within their limits, the present results indicate that treatment of Miller Class I and II multiple gingival recessions using PADM in conjunction with the MCAT could be successfully used as an alternative to connective tissue grafts, with the advantage of avoiding the discomfort and morbidity of connective tissue harvesting. CLINICAL SIGNIFICANCE The modified coronally advanced tunnel technique using the new porcine acellular dermal matrix represents a clinically and esthetically satisfactory treatment of multiple Miller Class 1 and 2 recession defects.

Efficiency of Er:YAG laser in debonding of porcelain laminate veneers by contact and non-contact laser application modes (in vitro study).

Abstract: Objective To determine the efficiency of debonding porcelain laminate veneers (PLV) by using several laser parameters and two different application modes of Er:YAG laser [contact (CM) and non-contact (NCM)], by verification of the consumed PLV debonding time and the changes in dental pulp temperature. Materials and methods Forty extracted non-carious human maxillary premolars were prepared for receiving PLV. Sixteen of them were divided into two groups, each of them comprised eight samples based on the application mode; group A with NCM, and group B with CM. Veneers of both groups were debonded by the same laser parameters (360 mJ, 15 Hz) during loading of a 15 N force on specially fabricated veneer cervical margins. The primary results showed that the NCM was more efficient, thus, additional groups (C, D, and E) of the same mode and number of samples were tested with different laser parameters of energy and frequency; group C (400 mJ, 10 Hz), group D (270 mJ, 15 Hz), group E (300 mJ, 10 Hz). The failure mode was determined and classified for the debonded samples of all groups. Results All veneers were debonded and samples of the NCM group had considerably lower debonding time (12.6 seconds) than the CM samples (96.3 seconds), however, higher changes of temperature in NCM (4.2°C) than in CM were observed (2.9°C). The failure mode of samples was either type 1 or 3. Conclusion Er:YAG laser is an effective tool in debonding PLVs. The NCM application mode was more efficient in reducing debonding time than CM application mode but with a higher change in pulp temperature. Clinical Significance Investigating the efficacy of Er:YAG laser as a non-invasive particle technique for debonding of failed or malpositioned of porcelain laminated veneers

A novel soft tissue thickness measuring method using cone beam computed tomography.

Abstract: OBJECTIVE The aim of this study was to introduce a novel soft tissue thickness measurement method using cone beam computed tomography (CBCT) and to compare the new method with ultrasonic device applications and transgingival probing measurements. METHODS Twenty-five participants (12 female, 13 male, age range, 25-51 years) were included the study. Soft tissue thickness in lateral incisor, canine, premolar, and molar regions were measured using transgingival probing (group T), ultrasonic device (group U), and CBCT scan measurements (group C). Differences and correlations between groups and agreement between measurement methods were evaluated. RESULTS Soft tissue thickness was significantly lower in group U in premolar region, but was significantly higher in molar region compared with group C and group T (P < .05). There were significant positive correlations in lateral incisor and canine region, between group U and group C, in premolar region between group T and group C, and in molar region between group U and group C, and between group C and group T (P < .05). The highest agreement between measurement methods was evident between group T and group C. CONCLUSION Soft tissue thickness values in maxilla may differ depending on the measurement method and location of the measurement. Ultrasonic device, transgingival probing, and CBCT measures may not necessarily correlate in all locations. The high agreement between CBCT measurements and transgingival probing may suggest the newly introduced method as a promising technique for soft tissue thickness evaluation. CLINICAL SIGNIFICANCE This study evaluated the relation between different soft tissue thickness measurement methods and demonstrated a novel method which can be used in any part of the mouth. The outcome also suggested that the measurement method and the location might affect the soft tissue thickness value obtained, and therefore might be important in clinical decision making.

Effects of adhesive used as modeling liquid on the stability of the color and opacity of composites.

Abstract: Objective This study evaluated the effects of adhesive type used as modeling liquid on the stability of the color and opacity of composites submitted to thermal cycling in staining solutions followed by a bleaching procedure. Methods Thirty cylinder-shaped composite specimens (10 mm diameter × 1.5 mm thickness) were built using or not using (control) an adhesive (Adper Universal or Scotchbond Multipurpose) as the modeling liquid. After polishing procedures, the color and opacity were measured, and the specimens were submitted to 200 thermal cycles with 10 s of dwell time in baths of grape juice at 5°C, water at 37°C, and coffee at 55°C. Changes in opacity and color caused by the staining solutions were measured. Then, the specimens were bleached with 35% hydrogen peroxide for 45 minutes followed by color/opacity measurements. Data were analyzed by ANOVA and Tukey's test (α = 0.05). Results The use of modeling liquids did not affect the initial color and opacity of composite. Reduced changes to color (E00 = 3.44) and opacity (+2.67%) were observed for specimens modeled using Adper Universal. Bleaching procedures reduced the color (E00 = 1.9-3.8) and opacity (-2.3 to 3.1%) alterations caused by staining solutions but were unable to restore the values observed at baseline. Conclusion The use of universal adhesive as modeling liquid significantly reduced the color and opacity changes caused by staining solutions, and the bleaching procedure partially re-established the opacity and color of the composites. Clinical significance This study evaluates whether using adhesive systems for modeling a composite affects the color and opacity changes caused by staining solutions followed by a bleaching procedure. The findings suggest that the use of a universal adhesive as modeling liquid can reduce the alterations in optical properties caused by staining solutions, and the application of high-concentrated hydrogen peroxide over the composite reduce the color changes without fully recover the initial color.