Effect of finish line location and saliva contamination on the accuracy of crown finish line scanning

PURPOSE

Intraoral scanners are used widely as an alternative to conventional impressions, but studies on the influence of finish line location and saliva contamination on scanning trueness are lacking. The purpose of this in vitro study was to evaluate the influence of finish line location and saliva contamination on the scanning trueness of crown finish lines.

MATERIALS AND METHODS

Three ivorine teeth were prepared for all-ceramic crowns with finish lines placed equigingivally, 0.5 mm subgingivally, and 1.0 mm subgingivally. A single-cord technique was used for gingival retraction, and a total of 180 intraoral scans were made using two intraoral scanners (Emerald; Planmeca USA Inc., Hoffman Estates, IL, USA & Trios 3; 3Shape A/S, Copenhagen, Denmark). The prepared teeth were separated from the dentoform and scanned using the same intraoral scanners to create reference scans. All scans were imported to the design software (Dental System 2019; 3Shape A/S, Copenhagen, Denmark). After marking the finish lines of prepared teeth, intraoral scans were aligned to the reference scans for comparisons. Vertical and horizontal marginal discrepancies were measured at four different measuring points (buccal, lingual, mesial, and distal) and analyzed. Two-way ANOVA and Tukey HSD tests were used for statistical analysis (α = 0.05).

RESULTS

The average vertical and horizontal discrepancies from various groups ranged from -33 to 440 µm. For both intraoral scanners, subgingival finish line groups showed greater vertical and horizontal discrepancies compared with equigingival finish line groups. Saliva contamination significantly increased both vertical and horizontal discrepancies for all finish line locations. The discrepancy increases due to saliva contamination were greater for the subgingival groups.

CONCLUSIONS

Subgingival finish lines were not accurately captured using the intraoral scanners. The presence of saliva significantly reduced scanning trueness, and this was amplified when the finish lines were located subgingivally.

Optimizing Dental Bond Strength: Insights from Comprehensive Literature Review and Future Implications for Clinical Practice

This review examines the modifying factors affecting bond strength in various bonding scenarios, particularly their relevance to the longevity of dental restorations. Understanding these factors is crucial for improving clinical outcomes in dentistry. Data were gathered from the PubMed database, ResearchGate, and Google Scholar resources, covering studies from 1992 to 2022. The findings suggest that for dentin-resin bonds, minimizing smear layers and utilizing MMP inhibitors to prevent hybrid layer degradation are essential. In the case of resin-resin bonds, reversing blood contamination is possible, but preventing saliva contamination is more challenging, underscoring its critical importance during clinical procedures. Additionally, while pretreatment on ceramics has minimal impact on bond strength, the influence of specific colorings should be carefully considered in treatment planning. This comprehensive review highlights that although established practices recognize significant bond strength factors, ongoing research provides valuable insights to enhance the clinical experience for patients. Once confirmed through rigorous experimentation, these emerging findings should be swiftly integrated into dental practice to improve patient outcomes.

Identification of Mycoplasma pneumoniae-associated pneumonia cases among hospitalized patients using CLART® microarray technology

Objectives

Community-acquired pneumonia (CAP) is a global health condition that affects populations from all age groups. The laboratory identification of Mycoplasma pneumoniae as a causative agent of CAP is challenging because of its atypical and fastidious nature. Therefore, this study assessed the diagnostic potential of PneumoCLART bacteria® in identifying M. pneumoniae as a causative agent of pneumonia in hospitalized adults.

Methods

This prospective study used a cross-sectional approach to assess the diagnostic potential of PneumoCLART bacteria® for detecting M. pneumoniae in sputum samples procured from 27 patients with pneumonia who required hospitalization.

Results

The PneumoCLART bacteria® results illustrated that 7 of 27 patients with pneumonia were positive for M. pneumoniae (26%). However, the quality of sputum varied among the M. pneumoniae-positive and M. pneumoniae-negative samples. Fifty percent of the specimens obtained from patients positive for M. pneumoniae were saliva-contaminated and unsuitable for analysis.

Conclusions

Because the leukocyte count was low and sputum specimens were saliva-contaminated, these findings require further validation to prove the utility of CLART® microarray technology for the identification of M. pneumoniae in pneumonia-positive patients. Conclusively, this prospective study included a small number of clinical samples, which likely affected its outcomes.

Which Zirconia Surface-cleaning Strategy Improves Adhesion of Resin Composite Cement after Saliva Contamination? A Systematic Review and Meta-Analysis

PURPOSE

To identify the most effective cleaning method for saliva-contaminated zirconia surface before adhesive cementation through a systematic review and meta-analysis.

MATERIALS AND METHODS

PubMed, Scopus, and Web of Science databases were searched to select in vitro studies published through October 2021. Studies that did not perform aging methods, had a sample size less than 5 per group, or did not present a group with zirconia contaminated only with saliva were excluded. Data were extracted and risk of bias was assessed. Statistical analysis comparing the cleaning methods was conducted, and the standardized mean difference was assessed using the R software program.

RESULTS

Among 804 potentially eligible studies, 36 were selected for full-text reading, of which 13 were included in qualitative analysis, and 11 of these were subsequently included in the quantitative analysis. A meta-analysis revealed a significant difference in the bond strength between the cleaning methods. Sandblasting with Al2O3  showed a higher bond strength than cleaning solution (Ivoclean, Ivoclar Vivadent) (p < 0.01, I2 = 65%), and both methods promoted higher resin-bond strength to zirconia than water cleaning. In addition, there was no significant difference in the bond strength between alcohol (p = 0.35, I2 = 79%), phosphoric acid (p < 0.23, I2 = 90%), and water cleaning.

CONCLUSION

Sandblasting with Al2O3 seems to be the best method for zirconia surface cleaning before adhesive luting, promoting better resin-bond strength to zirconia.

Immediate bond performance of resin composite luting systems to saliva-contaminated enamel and dentin in different curing modes

The purpose of this study was to evaluate the immediate shear bond strength of resin composite luting systems to tooth with or without saliva contamination in different curing modes. The Knoop hardness number of the resin composite luting agents was measured. Four combinations of resin composite luting systems were used. The shear bond strength to bovine teeth was measured with and without saliva contamination in different curing modes at different storage periods. The Knoop hardness number of the resin composite luting agents was also evaluated. Significantly lower enamel and dentin shear bond strengths and Knoop hardness number values were observed in all resin composite luting systems at 5 min versus 24 h, regardless of the curing mode or saliva contamination. The influence of the curing mode of the resin composite luting systems on shear bond strengths and Knoop hardness number was dependent on material. For the saliva contamination conditions, only G-CEM ONE EM did not show any significant difference in shear bond strength among the groups with and without saliva contamination, regardless of curing mode, storage period, or tooth substrate. All the resin composite luting systems showed lower shear bond strengths and Knoop hardness number values immediately after setting.

Retention Forces of Monolithic CAD/CAM Crowns Adhesively Cemented to Titanium Base Abutments-Effect of Saliva Contamination Followed by Cleaning of the Titanium Bond Surface

The aim of this study was to investigate the effects of saliva contamination and the cleaning of the bond surface of titanium base (ti-base) abutments on the bonding stability and retention force values. The bond surface of the ti-base abutments was treated with airborne-particle abrasion. After contamination, the ti-base abutments underwent different cleaning protocols: water spray (H2O); alcohol (ALC); suspension of zirconium particles (SZP); reapplied airborne-particle abrasion (APA); and a control condition without contamination and cleaning (CTR). All lithium disilicate crowns were bonded to the ti-base abutments using a primer and a self-curing composite. Bonded specimens underwent thermo-mechanical aging. Bond failure analysis and pull-off testing were performed. Bond failure occurred more frequently in groups H2O, ALC, SZP, and APA (p < 0.05). Significant differences in retention force values were only found between CTR and ALC (p < 0.05). Specimens which did not show bond failure after ageing had higher retention force values than the specimens that showed bond failure (p < 0.05). Saliva contamination with cleaning can degrade the bonding properties to titanium. For the retention force values, only the protocol with alcohol after contamination could not restore the values.

Does Rubbing of Universal Adhesive Reduce the Negative Effect of Saliva on Adhesion?

PURPOSE

To evaluate in vitro the effect of saliva contamination on bond strength of a universal adhesive applied with actively (with rubbing motion) and passively (without rubbing motion).

MATERIALS AND METHODS

A total of 144 bovine dentin samples were used, and the universal adhesive, Clearfil Universal Bond Quick, was either applied in accordance with the manufacturer's instructions (passive application) or applied with rubbing motion for 10 s (active application). These 2 groups were divided into 6 subgroups according to saliva contamination (n = 12): 1. control: etch-and-rinse (no saliva); 2. control: self-etch (no saliva); 3. etching/saliva/bonding; 4. etching/bonding/saliva; 5. saliva/bonding; 6. bonding/saliva. A resin composite, Filtek Ultimate, was filled into a polyethylene mold (0.9 mm diameter, 1.2 mm height) on the surfaces. Samples were subjected to microshear bond strength testing, and five specimens from each group were examined using SEM. Resin-dentin interfaces were also observed using transmission electron microscopy (TEM). All failure modes were determined using light microscopy. Statistical analyses were performed with two-way ANOVA, the Kruskall-Wallis test, and the Mann-Whitney U-test (p < 0.05).

RESULTS

Active-application groups showed statistically significantly higher bond strengths than did passive groups, regardless of adhesive strategy and saliva contamination (p < 0.05). Application of Clearfil Universal Bond Quick in self-etch mode with rubbing motion improved the µSBS among control groups (p < 0.05). The active application did not make a significant difference among the active groups (p > 0.05), except in group 2. Groups 2 and 5 showed significantly higher µSBS than group 3 among the passive groups (p < 0.05).

CONCLUSION

Rubbing the universal adhesives without any prior etching may increase the dentin bond strength. Following etching, passive application of the universal adhesive (without any additional rubbing motion) could affect the bonding to dentin in the presence of saliva.

In Vitro Evaluation of Different Protocols for Preventing Microleakage of Fissure Sealants Placed Following Saliva Contamination

PURPOSE

To evaluate the effect of different enamel conditioning protocols and their re-application on the microleakage of fissure sealants placed following saliva contamination.

STUDY DESIGN

The study included 156 human third molars in 16 subgroups (2×4×2) under two main groups (sealant type): Group A- hydrophobic resin sealant, 3M Clinpro™ Sealant; Group B- hydrophilic resin sealant, Ultraseal XT Hydro. Each group was then divided according to the type of surface conditioning; 1- Er,Cr:YSSG laser etching, 2- acid-etching, 3- acid-etching+etch-and-rinse adhesive (Prime&Bond® One Select) and 4- self-etching adhesive (Clearfil™ SE Bond). After contaminating the conditioned occlusal enamel surfaces with artificial saliva, fissure sealant was applied in half of the specimens (a), whereas in the other half, (b) the respective surface conditioning was repeated and then fissure sealant was placed. Following thermocycling, the samples were immersed in basic fuchsin, sectioned, and dye penetration was quantitatively assessed with ImageJ. Two-way ANOVA and Bonferroni post-hoc tests were used for statistical analyses (p<0.05).

RESULTS

The least microleakage was observed in A3b and A3a, whereas B4b and B4a were the subgroups with the highest microleakage. Following saliva contamination, when surface conditioning was not re-applied, the effects of fissure sealant types and surface conditioning were significant (p=0.005 and p<0.001, respectively). However, their interaction was insignificant (p=0.173). When surface conditioning was re-applied after saliva contamination, the effects of type of fissure sealant and surface conditioning (p=0.000, for both) and their interaction (p=0.004) were significant.

CONCLUSIONS

3M Clinpro™ Sealant was superior to Ultraseal XT Hydro. Re-application of Er,Cr:YSSG laser and the self-etching adhesive did not affect the microleakage of both fissure sealants. Without re-application, acid-etching+etch-and-rinse adhesive was superior to acid-etching only. However, both of them were similarly successful when they were re-applied following saliva contamination.

Technical note: Evaluation of the ororuminal FLORA sampling device for rumen fluid sampling in intact cattle

The objectives of this study were to evaluate the actual intraruminal sampling site of the ororuminal FLORA sampling device (Profs Products, Wittibreut, Germany), and to compare pH and volatile fatty acid (VFA) data obtained using FLORA and those obtained using a suction strainer introduced to the ventral ruminal sac via a rumen cannula. Five lactating multiparous Danish Holstein cows fitted with ruminal cannulas were used. All cows were fed the same diet once daily, and the diet was allowed ad libitum. Samples of rumen fluid and recordings were obtained 6 h after feeding at 3 occasions. Rumen fluid samples were taken using 2 devices: (1) the ororuminal FLORA sampling device and (2) a suction strainer inserted through the rumen cannula to the ventral ruminal sac and a 60-mL syringe for suction. Both sampling devices were inserted concomitantly, and samples of rumen fluid were obtained simultaneously with both devices. After sampling rumen fluid, the actual intraruminal placement of the FLORA sampling cup was manually assessed as being in either the cranial sac, the dorsal sac, the medial layer, or the ventral sac. Only VFA proportions, and not pH and VFA concentrations, were similar between rumen fluid samples obtained using FLORA and those obtained directly through the rumen cannula. The observed intraruminal sampling site of the FLORA sampling cup indicates that firm rumen digesta hampers the ability of the FLORA device to reach the ventral sac and impedes filling of the sampling cup and, consequently, increases the risk of saliva contamination of samples.

Effect of Surface Cleaning Regimen on Glass Ceramic Bond Strength

This study investigated the effect of saliva contamination on chemical changes of ceramic surface as well as the influence of saliva cleaning methods on ceramic-resin bond strength. Saliva was used to contaminate leucite (LGC) and lithium disilicate (LDGC) glass ceramic surfaces. The following cleaning methods were tested: water spray, cleaning with orthophosphoric acid, universal cleaning paste, ultrasonic cleaning with water, re-etching with hydrofluoric acid. Non-contaminated ceramic sample served as control. Chemical analysis of ceramic surfaces was performed using time-of-flight secondary ion mass spectrometry (TOF-SIMS). Shear bond strength (SBS) of ceramics to resin material was tested after 24-hour water storage and after thermocycling. The most effective cleaning method of saliva-contaminated ceramic surface was cleaning LGC surface with orthophosphoric acid or re-etching the LDGC surface with hydrofluoric acid. The application of the following methods resulted in obtaining reliable bond strength.

Immediate Repair Bond Strength of Fiber-reinforced Composite after Saliva or Water Contamination

PURPOSE

This in vitro study aimed to evaluate the shear bond strength (SBS) of particulate filler composite (PFC) to saliva- or water-contaminated fiber-reinforced composite (FRC).

MATERIALS AND METHODS

One type of FRC substrate with semi-interpenetrating polymer matrix (semi-IPN) (everStick C&B) was used in this investigation. A microhybrid PFC (Filtek Z250) substrate served as control. Freshly cured PFC and FRC substrates were first subjected to different contamination and surface cleaning treatments, then the microhybrid PFC restorative material (Filtek Z250) was built up on the substrates in 2-mm increments and light cured. Uncontaminated and saliva- or water-contaminated substrate surfaces were either left untreated or were cleaned via phosphoric acid etching or water spray accompanied with or without adhesive composite application prior applying the adherent PFC material. SBS was evaluated after thermocycling the specimens (6000 cycles, 5°C and 55°C).

RESULTS

Three-way ANOVA showed that both the surface contamination and the surface treatment signficantly affected the bond strength (p < 0.05). Saliva contamination reduced the SBS more than did the water contamination. SBS loss after saliva contamination was 73.7% and 31.3% for PFC and FRC, respectively. After water contamination, SBS loss was 17.2% and 13.3% for PFC and FRC, respectively. The type of surface treatment was significant for PFC (p < 0.05), but not for FRC (p = 0.572).

CONCLUSION

Upon contamination of freshly cured PFC or semi-IPN FRC, surfaces should be re-prepared via phosphoric acid etching, water cleaning, drying, and application of adhesive composite in order to recover optimal bond strength.

Effect of Decontamination and Cleaning on the Shear Bond Strength of High Translucency Zirconia

(1) Background: This study evaluated the bonding performance of high translucency zirconia after diverse surficial decontamination and cleaning procedures. (2) Methods: High translucency zirconia (Lava^TM Esthetic) specimens (2.0 mm × 20 mm × 10 mm) were exposed to different surface treatments prior to bonding to CoCr cylinders (d = 5 mm, height = 3 mm). All surfaces were sandblasted (40 µm aluminum oxide, 2 bar) and treated with alcohol (al), saliva (s), saliva + water (sw), or saliva + NaOCl + water (sn) before bonding was performed with the following adhesive luting systems: RelyX^TM Unicem 2 (RX), Scotchbond^TM Universal (SBU) + RelyX^TM Ultimate (RU) or Monobond Plus (MP) + Multilink^® Automix (ML). After 24 h, thermocycling (TC:12,000 × 5 °C/55 °C) and 90 days of storage at 37 °C in distilled water, the shear bond strength (SBS) was evaluated according to ISO/TS 11,405:2015. Failure modes along bonding areas were characterized. Means and standard deviations (n = 10 per group) were determined and statistically analyzed with one-way ANOVA/Bonferroni (α = 0.05). (3) Results: The SBS after 24 h varied between 3.5 (sRX) and 69.4 MPa (snMP + ML). Values from 0 (sRX) to 70.3 MPa (swRX) were found after TC. Data after 90 days of storage showed the lowest values for sRX (0 MPa) and the highest values for alSBU + RU (75.5 MPa). Adhesive failure was noted at all aging conditions. (4) Conclusions: SBU + RU or RX and MP + ML including saliva decontamination of the ceramic surface with water or NaOCl + water allow efficient bonding to Lava^TM Esthetic.

Cleaning Methods for Zirconia Following Salivary Contamination

PURPOSE

To determine the best method of cleaning saliva-contaminated zirconia in preparation for resin bonding.

MATERIAL AND METHODS

Flat blocks of zirconia were particle abraded with aluminum oxide and divided into eight groups (n = 10). Groups 1 to 4 were first treated with one coat of an MDP primer (Z-prime Plus) and groups 5 to 8 were left untreated. A thin coat of fresh whole saliva was painted on all specimens (except the control, group 1) and left in contact for 3 minutes. The specimens were then cleaned by rinsing with water for 20 seconds (groups 2 and 5), or cleaned with 35% phosphoric acid for 20 seconds and rinsed (groups 3 and 6), or cleaned with a zirconia cleaning solution (Ivoclean) for 20 seconds and rinsed (groups 4 and 7), or abraded with aluminum oxide particles and rinsed (group 5). Following the cleaning procedure, groups 5 to 8 were treated with one coat of Z-prime Plus. A 2.5 mm diameter tube was filled with composite (Z100), affixed to the zirconia surface, and light-cured. Specimens were stored in water (37°C for 24 hours) followed by thermocycling (5°C to 55°C for 10,000 cycles). Shear bond strength testing was performed at a crosshead speed of 1 mm/min. Bond strength values were compared to the control using a Dunnett's test (alpha = 0.05). Contact angles of the zirconia specimens with and without Z-prime Plus were measured with water using a goniometer.

RESULTS

Groups 2, 5, and 8 were not significantly different from the control. Application of Z-prime made the zirconia surface more hydrophobic.

CONCLUSIONS

If salivary contamination occurs after MDP application, rinsing off the saliva with water will preserve bond strength. If salivary contamination occurs prior to MDP application, particle abrasion or cleaning with Ivoclean will preserve bond strength.

Effect of different decontamination procedures from a saliva-contaminated cured bonding system (Single Bond)

BACKGROUND

A few studies have investigated the effect of saliva contamination of cured or uncured adhesive systems. The aim of this study was to compare the effect of different decontamination methods on the shear bond strength of composite to enamel and dentin using an adhesive contaminated after light activation.

MATERIALS AND METHODS

In this in vitro experimental study, 80 extracted sound human teeth, 40 premolars and 40 central incisors were selected for dentin and enamel specimen preparation. Within each of the two test groups, the teeth were randomly subdivided into five groups. The materials used consisted of single bond (3M) and Z250 (3M). Except group 1 (Control), in Groups 2-5, cured adhesive was contaminated with saliva (20 s). Decontaminating procedures were rinsing, blot-drying, rebonding (Group 2), rinsing, air-drying, rebonding (Group 3), etching, rinsing, blot-drying, rebonding (Group 4) and etching, rinsing, blot-drying (Group 5). Then, composite resin was inserted on the treated surfaces and cured. The results were subjected to one-way ANOVA and Tukey honestly significant difference (HSD) tests.

RESULTS

Group 5 (etching, rinsing, blot drying) resulted in significantly lower bond strength to both enamel and dentin surfaces in comparison with the other groups (P < 0.05).

CONCLUSION

When the adhesive was re-applied, all decontamination methods in this study seemed sufficient to decrease the adverse effect of saliva.