The Effect of Finishing and Polishing with Proprietary Vs Interchanged Polishing Kits on the Surface Roughness of Different Ceramic Materials.

PURPOSE: To evaluate the surface roughness of glazed and polished monolithic ceramic materials and to use this as a baseline for comparison after adjustment and polishing with both the recommended kit for the specific materials as well as interchanged polishing kits. MATERIAL AND METHODS: Flat ceramic specimens (n = 150) were fabricated from IPS ZirCAD Prime, IPS E.max, and Vitabloc Mark II. The specimens were adjusted and polished using either the proprietary polishing kit for the material or interchanged kits. The surface roughness was objectively assessed using Atomic Force Microscopy (AFM) and profilometer. Subjective assessment of surface finish was performed using a scanning electron microscope (SEM). Gravimetric weight loss of each sample was measured before and after polishing using a digital microscale. The mean surface roughness and standard deviation was calculated for each ceramic- polisher pair. A factorial ANOVA was used to compare the mean surface roughness values in nanometers between multiple groups (α = 0.05). The subjective results from the SEM were reported as descriptive statistics RESULTS: The zirconia polishing system produced surfaces with the lowest surface roughness regardless of the ceramic material. The polisher-ceramic combination was found to have a statistically significant effect on both Ra and RMS values when the AFM was used (p = 0.039 and 0.010, respectively). CONCLUSION: The zirconia polishing system resulted in the lowest surface roughness values regardless of ceramic materials tested. The zirconia polishing system also did not result in significant gravimetric weight loss regardless of the ceramic material used.

Bond Strength of Two Resin Cements with Leucite-reinforced Ceramic Using Different Bonding Agents.

AIM: To compare the bond strength of two resin cements to leucite-reinforced ceramics using three different boding agents and evaluate the compatibility of bonding agents. MATERIALS AND METHODS: Twenty extracted sound human molars were sectioned horizontally 2-3 mm above the cementoenamel junction (CEJ). CAD/CAM ceramic blocks for inLab were also sectioned to create 4 mm thick and bonded to the dentin. The adhesive groups assigned were divided into four adhesive groups: Group I: Variolink II dual-cure resin cement and Scotchbond Multi-Purpose Plus adhesive, group II: Multilink Automix dual-cure resin cement and Multilink primers, group III: Multilink Automix and Clearfil SE bond 2 (CSE2) adhesive, group IV: Multilink Automix and CSE2 with light curing after adhesive application. Five specimens of each group were sectioned perpendicular to obtain six microsticks of 1 × 1 mm width from each sample. Microtensile bond strength data were expressed in MPa. Fracture modes (FrMs) analyzed for the surfaces were divided into six patterns. Microtensile bond strength data were statistically analyzed with one-way ANOVA and Tukey post hoc tests (α = 0.05). T-test was performed at the 5% significance level to analyze groups III and IV with and without light curing. RESULTS: Group I showed the highest µTBS average of 13.67 MPa, group IV showed 12.26 MPa, group III showed 12.15 MPa, and group II showed the lowest average of 10.84 MPa. No significant differences were found between the bonding agents. However, the six types of failure modes, although all observed, were characterized by the adhesive system: Type I: adhesive failure of laminated dentin and ceramic; type II: adhesive failure of laminated ceramic; type III: adhesive failure of laminated dentin; type IV: cohesive failure of luting agent; type V: cohesive failure of dentin, and type VI: mixed failure of adhesion and cohesion. As a result, the FrM most commonly observed was the adhesive failure at the luting cement-ceramic block interface. CONCLUSION: The combination of resin cements and bonding agents did not significantly affect the bond strength of CAD/CAM ceramic restorations and dentin. CLINICAL SIGNIFICANCE: Several universal bonding agents are currently available for direct and indirect bonding, and using the same bonding agent for direct and indirect restorations could simplify inventory and benefit routine clinical practice. How to cite this article: Aida N, Koi K, Amaya-Pajares SP, et al. Bond Strength of Two Resin Cements with Leucite-reinforced Ceramic Using Different Bonding Agents. J Contemp Dent Pract 2023;24(11):859-863.

Development and maintenance of surface gloss of dental composites after polishing and brushing: Review of the literature.

OBJECTIVE: To describe the effect of the composites' composition to produce high surface smoothness/gloss using finishers/polishers, and to assess maintained smoothness/gloss under toothbrush abrasion. MATERIALS AND METHODS: PubMed papers published from January 01, 2000 to September 01, 2021 were included, and keywords used were: filler particle size, shape, amount of dental composites; finishing/polishing, gloss/roughness, and toothbrush abrasion of composites. Seventy-five in-vitro studies were included in this literature review. Forty-six articles assessed filler particle size/composition/shape and distribution to obtain high gloss/smoothness on different formulations; and the finishers/polishers effect on these materials. Twenty-nine papers assessed toothbrush abrasion of composites. RESULTS: Suprananofill/nanofill/microfills typically showed the smoothest and glossiest surfaces compared to nanohybrid, microhybrid and hybrid composites. Microfill (0.04-0.07 µm, 71-88 GU); suprananofill (0.001-0.8 µm, 52-92 GU), microhybrids (0.05-0.35 µm, 35-95 GU) and nanohybrids (0.05-0.21 µm, 66-97 GU). Composites with small, spherical particles tend to show smoother, glossier surfaces and more wear resistant compared to resin composites with larger or irregular particles. Several studies showed higher roughness and reduced gloss after toothbrush abrasion. CONCLUSIONS: Within the limitations of this study, suprananofill/nanofill/microfill composites tended to show the smoothest/glossiest surfaces due to smaller particle size. Composites with small, spherical particles tended to show smoother/glossier surfaces. Overall, toothbrush abrasion showed higher surface roughness and reduced gloss. CLINICAL SIGNIFICANCE: Suprananofills/nanofills/microfills had good polishability and polish retention due to their smaller particle size. The effectiveness of a polishing system is material-dependent. In general, Enhance-PoGo, Sof-Lex discs, and Sof-Lex Spiral wheels showed similar level of smoothness.

Visually acceptable gloss threshold for resin composite and polishing systems.

BACKGROUND: The objective of this study was to compare dentists' perceptions of gloss values of composite specimens with increased levels and to identify the gloss value considered to be clinically acceptable. METHODS: Disk-shaped composite specimens were finished and polished 3 ways: metallurgically using silicon carbide papers and alumina paste, manually using Enhance finisher and PoGo polisher (EP) (Dentsply Sirona), and manually using Sof-Lex (SLex) disks (3M). Specimens were produced with surface gloss ranging from 0 through 100 gloss units (GU) in increments of approximately 10 GU as measured with a glossmeter. A GU of 0 was nonglossy, and a GU of 100 was perfectly glossy. Ten dentists evaluated the specimens, ranking them in order from low to high gloss and in 4 groups: low (dull or rough), medium (moderate gloss, clinically unacceptable), high (glossy, clinically acceptable), and superior gloss. The authors performed Spearman correlation analysis (α = 0.05). RESULTS: For each finish and polish method, there was an excellent correlation between the machine-measured (actual) gloss ranks and the clinician-evaluated gloss ranks (r2 ≥ 0.95). There was no difference in perception of surface gloss of the composite when metallurgically polished (with silicon carbide papers and alumina paste) or polished with EP to the same GU. There was a slight difference in gloss perception when comparing the 2 different commercial polishing systems. CONCLUSIONS: Ten dentists consistently perceived gloss of 40 through 50 GU as clinically acceptable. However, the composite was considered clinically acceptable at a lower gloss (40 GU) when polished with SLex disks than when polished with EP or metallurgically (50 GU). PRACTICAL IMPLICATIONS: Gloss values of 40 through 50 GU are considered to be clinically acceptable for resin composites.

Periodontal phenotype: A review of historical and current classifications evaluating different methods and characteristics.

OBJECTIVE: To review the historical and current periodontal phenotype classifications evaluating methods and characteristics. Moreover, to identify and classify the methods based on periodontal phenotype components. OVERVIEW: Several gingival morphology studies have been frequently associated with different terms used causing confusion among the readers. In 2017, the World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions recommended to adopt the term "periodontal phenotype". This term comprises two terms, gingival phenotype (gingival thickness and keratinized tissue width) and bone morphotype (buccal bone plate thickness). Furthermore, gingival morphology has been categorized on "thin-scalloped", "thick-scalloped" and "thick-flat" considering the periodontal biotype. However, by definition, the term phenotype is preferred over biotype. Periodontal phenotype can be evaluated through clinical or radiographic assessments and may be divided into invasive/non-invasive (for gingival thickness), static/functional (for keratinized tissue width), and bi/tridimensional (for buccal bone plate thickness) methods. CONCLUSIONS: "Thin-scalloped," "thick-scalloped," and "thick-flat" periodontal biotypes were identified. These three periodontal biotypes have been considered in the World Workshop but the term periodontal phenotype is recommended. Periodontal phenotype is the combination of the gingival phenotype and the bone morphotype. There are specific methods for periodontal phenotype evaluation. CLINICAL SIGNIFICANCE: The term periodontal phenotype is currently recommended for future investigations about gingival phenotype and bone morphotype. "Thin-scalloped," "thick-scalloped," and "thick-flat" periodontal phenotypes can be evaluated through specific methods for gingival thickness, keratinized tissue width, and buccal bone plate thickness evaluation.

Vertical Marginal Discrepancy of Retrievable Cement/Screw-retained Design and Cement-retained Implant-supported Single Metal Copings.

AIM: To compare the vertical marginal discrepancy of retrievable cement/screw-retained design (RCSRD) and cement-retained (CR) implant-supported single metal copings cemented on implant abutments. MATERIALS AND METHODS: Single metal copings were fabricated for 20 4.5 × 10 mm titanium dental implants. Two groups of 10 implants each were randomly allocated. One group received RCSRD metal copings and the other group received CR metal copings. Both types of restorations were fabricated on solid abutments with 5.5 mm of diameter. The copings were cemented with resin cement. After the cementation procedure, cement excess was carefully removed in both groups. Inspections of coping-abutment vertical marginal discrepancy were measured using scanning electronic microscopy (SEM) under 800× magnification. The independent sample Student's t test was used to detect differences between groups (p < 0.05). RESULTS: The RCSRD implant-supported metal coping group (57.80 ± 2.34 µm) showed statistically better vertical marginal discrepancy than the CR implant-supported metal coping group (64.40 ± 2.23 µm) (p = 0.001). CONCLUSION: The RCSRD implant-supported metal copings offer less vertical marginal discrepancy than the CR copings group. This new technique would decrease the marginal discrepancy with less bacterial filtration and biomechanical problems. CLINICAL SIGNIFICANCE: Retrievable cement/screw-retained design is another alternative technique for dental implant rehabilitation that combines the advantages of CR and SR prostheses. The hybrid design offers less vertical marginal discrepancy for better control of bacterial filtration and biomechanical problems.

Fracture Resistance of Cement-retained, Screw-retained, and Combined Cement- and Screw-retained Metal-ceramic Implant-supported Molar Restorations.

AIM: To compare fracture resistance between the cement-retained (CR), screw-retained (SR), and combined cement- and screw-retained (CCSR) metal-ceramic (MC) implant-supported molar restorations and the fracture mode after vertical loading simulation. MATERIALS AND METHODS: Thirty MC molar restorations were fabricated on thirty tilted dental implants that were repositioned using prefabricated or universal castable long abutments (UCLA) with 15° of angulation divided into three groups of ten specimens each. Group C: CR, group S: SR, and group CS: cement- and screw-retained. The crowns in group CS were adhesively bonded extraorally, and composite resin was used to fill the screw access holes (SAHs) in groups S and CS. Subsequently, all the specimens were tested for fracture resistance. A scanning electron microscope (SEM) evaluation of the fracture mode was also performed. Mean values of fracture loads were calculated and compared in Newtons (N) using one-way ANOVA and Tukey post hoc test (p < 0.05) for each group. RESULTS: Mean fracture load values were 2718.00 ± 266.25 N for group C, 2125.10 ± 293.82 N for group S, and 2508.00 ± 153.59 N for group CS. Significant differences were found between group S and the other groups on fracture load values. However, no significant differences were found between groups C and CS (p = 0.154). The failures were at MC framework interfaces on mesiolingual cusps. CONCLUSIONS: Cement and CCSR MC molar restorations showed comparable fracture resistance using abutments with 15° of angulation. However, SR design showed significantly the lowest values of resistance. Screw access hole did not significantly affect the fracture resistance of cemented MC molar restorations. All the specimens exhibited mixed adhesive fractures at the mesiolingual cusps. CLINICAL SIGNIFICANCE: Combined cement- and screw-retained restorations (CCSRRs) incorporate the simplicity of the cement method and the retrievability of the screw method, offering good resistance, allowing the removal of the excess of cement before clinical placement of the restoration, and providing another alternative for dental implant rehabilitation.

Techniques for retrievability and for registering screw access holes in cement-retained implant-supported prostheses: A scoping review of the literature.

STATEMENT OF PROBLEM: After implant rehabilitation, clinicians may need to remove a restoration because of technical and biological complications. For cement-retained implant-supported prostheses (ISPs), the retrievability process may damage the components of the prosthesis, the intaglio surface of the implant, or the abutment screw. To avoid that, the screw access hole (SAH) of the dental implant abutment (DIA) should be registered. Although several clinical reports and dental techniques have been proposed, a review of existing techniques is lacking. PURPOSE: The purpose of this scoping review was to evaluate the different techniques described for retrievability and for registering the SAH of cement-retained ISPs. MATERIAL AND METHODS: An electronic search of English language dental literature in the PubMed, Scopus, Google Scholar, and SciELO databases was conducted from 1980 to December 2017 with appropriate keywords and phrases. A hand search of relevant dental journals was also completed, and exclusion criteria were applied after full-text evaluation. RESULTS: The electronic and hand search revealed 325 articles. However, 252 publications were discarded after duplicates were removed. After reading the title and abstracts, 15 studies were excluded, and the full text of 64 publications was screened for inclusion and exclusion criteria. Forty studies were selected and included for final evaluation. The evaluation revealed 6 techniques for retrievability and 9 techniques for registering the position of the SAH, divided into 2-dimensional (2D) and 3-dimensional (3D) techniques. CONCLUSIONS: Cement-retained ISPs can be effectively retrieved by using interim cements and possibly by using a combined cement- and screw-retained design. Vacuum guides with guiding sleeves and computer-aided design and computer-aided manufacturing (CAD-CAM) guide templates are possible effective 3D techniques for registering the screw access channel (SAC) location and angulation.

Implant Rehabilitation Partial Maxillary Edentulism with Onlay Autogenous Chin Bone Grafting and Prosthetic Gingival Restoration: A Case Report.

BACKGROUND: Atrophic anterior maxilla rehabilitation can be a challenging procedure due to multiple factors that influence clinical decision making. After a prolonged loss of teeth, the residual bone often impedes the use of standard implant placement protocols and additional procedures are needed. AIM: The aim of this study is to describe the multidisciplinary approach for the diagnosis and treatment of a 50-year-old woman with prolonged use of a removable maxillary partial denture. CASE DESCRIPTION: This article presents a full-mouth-phased rehabilitation of an atrophic anterior maxilla with three surgical stages. First, onlay autogenous chin bone grafting was used to return the lost tissue. After the consolidation, dental implants were placed in a second stage. A few months later, a connective tissue graft was used to improve the keratinized mucosa width. In the mentioned stages, leukocyte- and platelet-rich fibrin (L-PRF) was used to improve healing and promote tissue regeneration. Finally, prosthetic gingival restoration was used in the anterior region as an alternative to overcome the limitations of hard- and soft-tissue grafting. CONCLUSION: The use of autogenous grafts obtained from the chin in combination with xenograft and then covered with an absorbable collagen membrane represents a predictable procedure for the rehabilitation of the long-term partial maxillary edentulism. Prosthetic gingival restoration is an alternative technique to overcome the limitations of hard- and soft-tissue grafting. CLINICAL SIGNIFICANCE: The treatment of a patient with high and width alveolar bone loss needs a multidisciplinary approach. Autogenous grafts obtained from the chin in combination with xenograft and then covered with an absorbable collagen membrane represent an effective procedure. Also, prosthetic gingival restoration can be used as an alternative technique to overcome the limitations of hard- and soft-tissue grafting.

Effect of Finishing and Polishing on the Surface Roughness of Four Ceramic Materials after Occlusal Adjustment.

PROBLEM: Intraoral occlusal adjustment of ceramic restorations can create a significant increase in surface roughness that can produce wear of the opposing dentition. PURPOSE: To compare the surface roughness of glazed and polished monolithic ceramics with the surface roughness produced by different intraoral polishing systems on adjusted monolithic ceramics. MATERIALS AND METHODS: Milled ceramic discs (10 mm diameter × 2 mm thickness) were manufactured and distributed according to the following groups (n = 10): BruxZir (glazed and polished), Zenostar (glazed and polished), IPS Empress CAD, and IPS e.max CAD. Surface roughness, expressed as arithmetic average height (Ra ), was measured using atomic force microscope and profilometer before and after adjustment and polishing with the following intraoral polishing systems: BruxZir and Dialite ZR (for BruxZir), Zenostar and Dialite ZR (for Zenostar), and OptraFine and Dialite LD for IPS Empress CAD and IPS e.max CAD. Mean and standard error for each material and polishing system were calculated. T-test, one-way ANOVA, and Bonferroni post hoc tests were used to analyze data. RESULTS: BruxZir zirconia presented smoother surfaces with Dialite ZR system compared to BruxZir system, Zenostar zirconia shown smoother surfaces with Zenostar system compared to Dialite ZR system and IPS Empress CAD and IPS e.max CAD presented smoother surfaces with OptraFine system in comparison to Dialite LD system. CONCLUSION: All materials presented smoother surfaces at baseline than after adjustment and polishing. CLINICAL SIGNIFICANCE: This paper reveals the results of an in vitro study that provides information to clinicians regarding which intraoral polishing system will produce a smoother surface after the adjustment and polishing of IPS Empress CAD, IPS e.max CAD, BruxZir and Zenostar ceramic materials. (J Esthet Restor Dent 28:382-396, 2016).