CRIS Guidelines (Checklist for Reporting In-vitro Studies): A concept note on the need for standardized guidelines for improving quality and transparency in reporting in-vitro studies in experimental dental research

Biomechanical comparison of the efficacy of Cfr-PEEK and titanium systems in the fixation following sagittal split advancement osteotomy: a biomechanical study

BACKGROUND

This study evaluates the efficacy of carbon fiber reinforced Polyetheretherketone (Cfr-PEEK) in fixation after sagittal split ramus osteotomy (SSRO) by comparing it with titanium in vitro.

METHODS

Twenty-eight sheep hemimandibles were randomly assigned to four groups for SSRO surgery. Fixation was performed with a 4-hole titanium mini plate for 5 mm advancement in Group 1, with a 4-hole Cfr-PEEK mini plate for 5 mm advancement for Group 2, with a 4-hole titanium mini plate for 10 mm advancement for Group 3, and with a 4-hole Cfr-PEEK mini plate for 10 mm advancement for Group 4. A linear vertical load of 50 N was applied to all models from the molar region. Displacement values were recorded digitally.

RESULTS

There was a significant difference among the displacement values of four groups (p < 0.05). The highest displacement values were observed in group 2 and the lowest in group 3. The Cfr-PEEK plates' fixed groups showed lower displacement values than their titanium counterparts.

CONCLUSIONS

According to this study, Cfr-PEEK provides better stability than titanium by considering the displacement values. However, future experimental and clinical studies that include larger samples and different designs need to be done.

Comparative Evaluation of the Dimensional Accuracy of Silicone-Based Putty Reline Impressions with Different Spacer Acquisition Techniques in Fixed Partial Dentures

BACKGROUND A tooth preparation's clinical requirements and geometric configurations should take precedence over material characteristics when advocating for putty reline impression techniques for permanent restorations, since they require a technically sensitive spacer for light body elastomer. We evaluated the linear dimensional accuracy of vinyl polysiloxane-based putty reline impressions with different spacer acquisition techniques in short-span and long-span fixed partial dentures (FPD). MATERIAL AND METHODS A typodont tooth set simulated a 3-unit (short-span) and a 5-unit (long-span) FPD. Between respective prepared abutments, 31 coordinates were identified and measured based on angles (line/point) and surfaces (curved/flat). Sixty impressions (dual stage 2-step putty reline technique) were divided into 5 groups (n=12/group): group PP (pre-preparation putty), group GP (gouging putty), group PS (polythene spacer), group CT (conventional temporary), and group MT (modified temporary), depending on spacer acquisition method. Coordinates measurements were conducted using a measuring microscope. Descriptive and inferential statistical tests (ANOVA, post hoc Tukey) determined between-group and within-group differences, at P≤0.05 significance level. RESULTS In short-span FPD, compared with control, the number of significantly different coordinates group-wise were GP (4 coordinates), PP (2 coordinates), and PS, CT, and MT (1 each). In long-span FPD, compared with control, the number of significantly different coordinates group-wise were group GP (12 coordinates), group PP (10 coordinates), group PS (5 coordinates), and group CT and group MT (4 each). CONCLUSIONS Different spacer acquisition methods produce varied thickness of spacers for relining of putty. CT and MT, when used as spacers, provided maximum accurate coordinates for angles (line/point) and surfaces (curved/flat).

Changes in optical properties of aesthetic paediatric restorative materials following exposure to beverages: In-vitro study

PURPOSE

Optical properties of recent aesthetic restorative materials must maintain an acceptable appearance throughout their functional lifetime. This study aimed to assess the changes in translucency and colour of recent resin-based restorative materials after exposure to beverages commonly consumed by children.

METHODS

An experimental in-vitro study on 48 discs specimens prepared from; Group I: Filtek Z250 XT (Nanohybrid), Group II: Cention N (Alkasite bulkfill), and Group III: SDR flow Plus (Flowable bulkfill). The prepared disc specimens were randomly assigned into 4 subgroups (n = 12) according to the immersion solution: Subgroup A (control): distilled water, B: Coca-Cola, C: chocolate milk, and D: Orange juice. Translucency and colour measurements were done before immersion (baseline) and on day 30 of exposure. Statistical analysis involved Two Way Repeated Measures ANOVA and Kruskal-Wallis test.

RESULTS

The statistical analysis revealed that the restorative material, immersion time, and immersion solution had a significant effect on the change in translucency (p < 0.0001*, p < 0.0001*, p = 0.001*, respectively). Regarding colour changes, different immersion solutions had a statistically significant effect on Filtek Z250 XT and Cention N (p < 0.0001*). Distilled water and Coca-Cola were found to have a significant effect on colour change for all restorative materials investigated (p < 0.0001*, p = 0.003*).

CONCLUSION

the optical properties of resin-based restorative materials used in paediatric dentistry were notably affected by prolonged exposure to beverages commonly consumed by children.

The evaluation of internal adaptation of glass ionomer restorations applied after the use of different cavity conditioners in primary teeth: an in-vitro study

BACKGROUND

This study aimed to comparatively evaluate the effects of different cavity conditioners on internal adaptation (IA) of glass ionomer-based restorative materials applied to primary teeth.

METHODS

80 extracted primary second molar teeth were randomly assigned to four different cavity conditioner groups [10% polyacrylic acid, 20% polyacrylic acid, 17% ethylene diamine tetraacetic acid (EDTA), 35% phosphoric acid]. Class V cavities were prepared on the buccal surfaces and relevant cavity conditioners were applied, and the samples in each cavity conditioner group were randomly assigned to glass hybrid (GHR) or conventional glass ionomer restoratives (CGIR). Subsequently, restorative materials were applied and all samples were thermocycled (5-55 °C, 5000 cycles) and IA were calculated volumetrically by using a Micro Computed Tomography (Micro-CT) system. IA values was recorded as % and data were analyzed with Mann-Whitney U and Kruskal-Wallis H tests. Statistical significance level was set as 5%.

RESULTS

35% phosphoric acid showed the lowest mean internal voids (between the cavity-restoration interface) for both restorative materials (for GHR = 0.180% and for CGIR = 0.936%). However, the highest mean internal voids for GHR and CGIR were observed after the use of 17% EDTA (2.438%) and 10% polyacrylic acid (8.483%), respectively. For both restorative materials, 20% polyacrylic acid showed the second lowest mean internal voids (for GHR = 0.321% and for CGIR = 3.580%), however, no significant difference was found between 35% phosphoric acid and 20% polyacrylic acid (p = 0.941 for GHR and p = 0.061 for CGIR). In the samples applied the cavity conditioners other than 17% EDTA, glass hybrid restoratives showed significantly higher IA quality than conventional glass ionomer (p = 0.0001 for 10% polyacrylic acid, p = 0.001 for 20% polyacrylic acid and p = 0.002 for 35% phosphoric acid).

CONCLUSIONS

Within the limitations of this study, 35% phosphoric acid and 20% polyacrylic acid were determined to be the most successful cavity conditioners in terms of IA, and glass hybrid restorative system showed superior IA quality than conventional glass ionomer. Further studies are needed to confirm the present results.

Impact of S-PRG/Giomer and Bulk-fill technologies on the hygroscopic profile of resin composites under erosive condition

OBJECTIVE

The emergence of new resin composites (RCs) incorporating bioactive ingredients and/or used as bulk-fill materials aims to enhance restorative potential beyond just the mechanical properties. However, this innovation may affect their performance under clinically simulated conditions, such as erosive challenges (EC). This study evaluated the impact of different technologies on the hygroscopic properties of RCs.

MATERIALS AND METHODS

The evaluated materials were: Gold Label - GL (resin-modified glass-ionomer cement - control); Filtek Z350 - FZ (no bioactive control); Filtek One Bulk - FO (bulk-fill); Beautifil II - BII (bioactive/S-PRG); Beautifil Bulk - BB (bioactive/S-PRG + bulk-fill). Disk-shaped specimens (10 mm x1 mm) were prepared and evaluated by: 1) water sorption - WS and solubility - WSB (n = 10); 2) wettability - W (n = 6); 3) surface microhardness - SM (n = 6); 4) qualitative surface analysis by SEM (n = 3). Except for WS and WSB, tests were performed before and after EC. Data were analyzed by two-factor ANOVA and Tukey tests (p < 0.05).

RESULTS

Positive WS and negative WSB were observed for all materials. In terms of W, GL>BII>FZ>BB>FO. GL and BB exhibited similar/lower SM. EC hampered SM for all materials.

CONCLUSIONS

It may be concluded that the composition and proportion of monomers have a greater influence on the hygroscopic profile of resin composites than the incorporation of bioactive components.

CLINICAL SIGNIFICANCE

While renewed technologies have introduced components to enhance the performance and practicality of resin composites, actual clinical longevity depends on challenges such as erosive conditions. Bioactive ingredients seem to be beneficial without impairing the hygroscopic profile, whereas the monomers can interfere.

In situ evaluation of microbial profile formed on Ti-6Al-4V additive manufacturing disks: 16S rRNA sequencing

STATEMENT OF PROBLEM

Dental implants obtained by additive manufacturing may present changes in the microbiome formed. However, studies profiling the microbial communities formed on Ti-6Al-4V are lacking.

PURPOSE

The purpose of this in situ study was to characterize the profile of the microbial communities formed on Ti-6Al-4V disks produced by additive manufacturing and machining.

MATERIAL AND METHODS

Titanium disks produced by additive manufacturing (AMD) and machining (UD) were housed in the buccal region of removable intraoral devices. These devices containing both disks were used by eight participants for 96 hours. After every 24 hours of intraoral exposure, the biofilm that had formed on the disks was collected. The 16S rRNA genes from each specimen were amplified and sequenced with the Miseq Illumina instrument and analyzed. Total microbial quantification was evaluated by analysis of variance-type statistics using the nparLD package. The Wilcoxon test was used to evaluate alpha diversity (α=.05).

RESULTS

A difference was found in the microbial communities formed on additively manufactured and machined disks, with a reduction in operational taxonomic units (OTUs) for the AMD group compared with the UD group. Firmicutes and Proteobacteria were the most abundant phyla. Of the 1256 genera sequenced, Streptococcus predominated on both disks.

CONCLUSIONS

The microbiome of the biofilm formed on the Ti-6Al-4V disks was significantly influenced by the fabrication method. The AMD disks showed lower total microbial counts than the UD disks.

The evaluation of the accuracy of a wireless electronic apex locator in primary molar teeth

BACKGROUND

The working length determination is necessary before root canal shaping, chemical cleaning, disinfection, and obturation in pulpectomy of primary dentition. This study aimed to evaluate the accuracy of Wirele-X and compare it with DentaPort ZX and Woodpex III in primary molar teeth.

METHODS

The in vitro study was performed by using 30 extracted primary mandibular molar teeth. In distal roots, the actual working length was determined by taking forward a #10 K-type canal file under a dental operating microscope with 10x magnification. Each tooth and lip clip were embedded in alginate before determining the working lengths using electronic apex locators. The average of three electronic working lengths was calculated for each sample, and the actual working length was subtracted from the electronic working length.

RESULTS

There were no significant differences in the accuracy rate of DentaPort ZX, Wirele-X, and Woodpex III in the determination of the working length set at ± 0.5 mm and ± 1 mm, respectively (P > 0.05).

CONCLUSIONS

This study reported that DentaPort ZX, Wirele-X, and Woodpex III can be safely used in the pulpectomy of primary molars. Wirele-X can provide an advantage in working length determination in children because of its wireless feature.

The Influence of the Degree of Dental Implant Insertion Compression on Primary Stability Measured by Resonance Frequency and Progressive Insertion Torque: In Vitro Study

Background: This study aimed to evaluate the primary stability, according to the insertion torque value (ITV) and resonance frequency analysis (RFA), of dental implants placed in standardized blocks of bone quality equivalent to type II-A bone, using three surgical undersized protocols of 0.2 mm, 0.5 mm, and 0.8 mm, considering different dental implant diameters and lengths. Methods: One hundred and twenty dental implants (DIs) of different diameters (3.5, 3.8, 4.5, and 5.0 mm) and lengths (8.5, 10.0, 11.5, 13.0, and 15.0 mm) placed in polyurethane blocks equivalent to type II-A bone, according to the Lekholm and Zarb classification modified by Rosas et al., were examined with three surgical protocols of under-milling of 0.2, 0.5, and 0.8 mm. The ITV and the RFA were the determinants of primary stability, and their respective values were recorded as Ncm and the implant stability quotient (ISQ) immediately after the placement of the DIs. These were evaluated according to each surgical insertion protocol, length, and diameter of the DI under a multivariate analysis model (MANOVA). Statistical significance was set at p < 0.05. Results: It was observed that the average of the ITV was significantly higher when a 0.8 mm under-milling protocol was used (63.2 ± 14.9 Ncm) (p < 0.001). However, the ITV was significantly lower when a 0.2 mm under-milling protocol was used (25.1 ± 8.3 Ncm) (p < 0.001). On the other hand, the ISQ did not present significant differences (p = 0.166) when comparing the 0.2 (67.6 ISQ ± 5.4 ISQ), 0.5 (65.8 ISQ ± 3.4 ISQ), and 0.8 (65.7 ISQ ± 4.0 ISQ) under-milling protocols in the evaluation of the primary stability of the dental implant. The multivariate effect size (ηp2 = 0.639) indicated that the variability detected in the insertion torque and the ISQ, at the same time, was explained by 63.9% (p < 0.001) due only to the compression protocol, while the implant diameter explained this variability by 27.0% (ηp2 = 0.270) (p < 0.001) and the implant length only significantly explained this variability by 12.1% (ηp2 = 0.121) (p = 0.030). Finally, any interaction between the compression protocol, implant diameter, and length did not influence insertion torque variability or the ISQ (p > 0.05). Conclusions: It can be concluded that when the surgical protocol for subpreparation is optimal according to the prepared bone bed, regardless of the diameter or length of the dental implant used, primary stability was assured according to the ITV and the RFA in 63.9%. This finding allows us to recommend carrying out a correct analysis of bone quality in order to subsequently select the most appropriate surgical protocol for the subpreparation of the bone bed to achieve better primary stability of the dental implant.

Microtensile Bond Strength and Failure Mode of Different Universal Adhesives on Human Dentin

AIM

The aim of this study was to compare the microtensile bond strength (µTBS) and failure mode of 4 different universal adhesive systems (UAs) on human dentin.

MATERIALS AND METHODS

The study sectioned the occlusal thirds of 32 human third molars and divided them into 4 groups based on the adhesive system used. Group A: Palfique Universal Bond, Group B: Single Bond Universal, Group C: All-Bond Universal, and Group D: One Coat 7 Universal. The specimens underwent a 10,000-cycle thermocycling ageing process prior to testing (n = 32). Afterwards, 8 beams were obtained per group and subjected to µTBS testing using a digital universal testing machine at a speed of 1 mm/min. The microtensile bond strength values were analysed in Megapascals (MPa), and the failure mode was evaluated using a stereomicroscope. Welch's parametric ANOVA with robust variance and the Games-Howell post hoc test were used for µTBS comparisons, and Fisher's exact test was used to determine the association between adhesive type and failure mode. The significance level was set at P < .05.

RESULTS

Group D showed a significantly higher µTBS than groups A (P < .001) and B (P < .001), but no significant difference was observed with group C (P= .075). Furthermore, groups B and C showed significantly higher µTBS than group A (P< .001 and P < .001, respectively), but there was no significant difference between groups B and C (P = .132). Additionally, group A exhibited a significant association with an adhesive failure mode (P < .05), whereas groups B, C, and D were significantly associated with a mixed failure mode (P < .05).

CONCLUSION

The One Coat 7 Universal adhesive system showed higher microtensile bond strength values and higher chemical interaction with dentin compared to Palfique Universal Bond and Single Bond Universal. However, no significant differences were observed compared to All-Bond Universal.

An in-vitro study on accuracy of modular templates used to fully guide implants in combination with bone reduction for complete arch restorations: Experts versus students

OBJECTIVES

This in-vitro study evaluates the accuracy of modular surgical templates used to fully guide implants in combination with bone reduction, performed by expert and students, for complete arch restorations.

METHODS

All the procedures were performed by dental students of the final year and an expert clinician, on twelve edentulous mandible models. A virtual implant planning, simulating a complete arch restoration on six implants were performed. Three different surgical guides were designed and printed to allow conventional fully guided implant placement (group 1); fully guided implant placement with modular guides (group 2); and fully guided implant placement after bone reduction, with similar, modular guides (group 3). After implant placement, optical scans of the study models were taken. Surface deviation and accuracy were evaluated and compared between groups and subgroups.

RESULTS

A total of 12 surgical templates were used. Of these, Two templates in each group were used by two different students, while, the other six templates were used by an expert clinician as follows: one template with screwed anchor pins and one with pushed anchor pins in each group. A total of 72 implants were placed. Statistically significant difference was found between different template designs, when the implants were placed by an expert clinician. No statistically significant difference was found between expert and students, except the deviation in an angle value (students 2.13±1.46° versus expert 0.90±0.91°; P Value=0.0447) in the group 3. A statistically significant difference was found in favor of screwed anchor pins, in the group 1, in horizontal deviation (screwed pins 0.18±0.13 mm versus pushed pins 0.56±0.28 mm; P Value=0.0124; Table 5). No statistically significant difference was found between different template designs when the fully guided implants were placed by students, in both angle and horizontally (P=0.2787 and P=0.6601, respectively). A statistically significant difference was found between groups when the implants were placed by an expert clinician, with better value using screwed anchor pins, in the horizontal plane (P= 0.0293) but not in angle (P= 0.3380).

CONCLUSIONS

Modular templates provide a similar level of accuracy to conventional, one-piece guides. Screwed pins should be used to fix the base portion of the modular guides. Further clinical studies are needed to confirm these preliminary results.

CLINICAL SIGNIFICANCE

Modular surgical guides provide comparable accuracy to conventional, single-piece guides, however they offer more possibilities, helping in bone reduction and immediate loading procedures. Screwed anchor pins used to fix the base portion of the modular guides provide better final results than pushed pins.

High-Intensity Interval Training Mitigates Sarcopenia and Suppresses the Myoblast Senescence Regulator EEF1E1

BACKGROUND

The optimal exercise regimen for alleviating sarcopenia remains uncertain. This study aimed to investigate the efficacy of high-intensity interval training (HIIT) over moderate-intensity continuous training (MICT) in ameliorating sarcopenia.

METHODS

We conducted a randomized crossover trial to evaluate plasma proteomic reactions to acute HIIT (four 4-min high-intensity intervals at 70% maximal capacity alternating with 4 min at 30%) versus MICT (constant 50% maximal capacity) in inactive adults. We explored the relationship between a HIIT-specific protein relative to MICT, identified via comparative proteomic analysis, eukaryotic translation elongation factor 1 epsilon 1 (EEF1E1) and sarcopenia in a paired case-control study of elderly individuals (aged over 65). Young (3 months old) and aged (20 months old) mice were randomized to sedentary, HIIT and MICT groups (five sessions/week for 4 weeks; n = 8 for each group). Measurements included skeletal muscle index, hand grip strength, expression of atrophic markers Atrogin1 and MuRF1 and differentiation markers MyoD, myogenin and MyHC-II via western blotting. We examined the impact of EEF1E1 siRNA and recombinant protein on D-galactose-induced myoblast senescence, measuring senescence-associated β-galactosidase and markers like p21 and p53.

RESULTS

The crossover trial, including 10 sedentary adults (32 years old, IQR 31-32) demonstrated significant alterations in the abundance of 21 plasma proteins after HIIT compared with MICT. In the paired case-control study of 84 older adults (84 years old, IQR 69-81; 52% female), EEF1E1 was significantly increased in those with sarcopenia compared to those without (14.68 [95%CI, 2.02-27.34] pg/mL, p = 0.03) and was associated with skeletal muscle index (R2 = 0.51, p < 0.001) and hand grip strength (R2 = 0.54, p < 0.001). In the preclinical study, aged mice exhibited higher EEF1E1 mRNA and protein levels in skeletal muscle compared to young mice, accompanied by a lower muscle mass and strength, increased cellular senescence and protein degradation markers and reduced muscle differentiation efficiency (all p < 0.05). HIIT reduced EEF1E1 expression and mitigated age-related muscle decline and atrophy in aged mice more effectively than MICT. Notably, EEF1E1 downregulation via siRNA significantly counteracted D-galactose-induced myoblast senescence as evidenced by reduced markers of muscle protein degradation and improved muscle differentiation efficiency (all p < 0.05). Conversely, treatments that increased EEF1E1 levels accelerated the senescence process (p < 0.05). Further exploration indicated that the decrease in EEF1E1 was associated with increased SIRT1 level and enhanced autophagy.

CONCLUSIONS

This study highlights the potential of HIIT as a promising approach to prevent and treat sarcopenia while also highlighting EEF1E1 as a potential intervention target.

Exploring the Impact of Access Cavity Designs on Canal Orifice Localization and Debris Presence: A Scoping Review

OBJECTIVES

One of the primary objectives in endodontics is to achieve thorough cleaning and disinfection of the root canal system during an endodontic procedure. This aims to reduce microbial contamination and prevent the development of endodontic lesions. To attain this goal, it is imperative to establish access to the endodontic space that allows for the complete removal of pulp tissue and the accurate identification of canal orifices while preserving the anatomical integrity of the root floor and pulp chamber as much as possible. In this scoping review, we aim to explore aspects related to the identification of canal orifices and the presence of pulp debris and residues during endodontic treatment. Specifically, we aim to assess whether and to what extent the design of the access cavity impacts these factors.

MATERIAL AND METHODS

The scoping review was conducted and prepared following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines (PRISMA Extension for Scoping Reviews [PRISMA-ScR]).

RESULTS

The search yielded a total of 3697 bibliographic sources. After eliminating duplicates and applying eligibility criteria, only 10 studies were included.

CONCLUSIONS

In conclusion, our review, conducted following PRISMA guidelines, includes 10 studies and suggests a potential trend: conservative techniques may generate more debris, whereas guided techniques exhibit superior precision in locating canal openings.

Microleakage of luting cements in CAD/CAM pediatric zirconia crowns: an in vitro study

The durability of pediatric zirconia crowns for primary teeth is influenced by the choice of luting cement, with the effectiveness of the cement being directly correlated to its ability to reduce microleakage. This in vitro study aimed to assess and compare the microleakage of custom-made zirconia crowns (CZCs) and prefabricated zirconia crowns (PZCs) on primary maxillary incisors when luted with self-adhesive resin cement, resin-modified glass ionomer cement (RMGIC), and bioactive cement. Sixty primary maxillary incisors were prepared and allocated into two groups, each corresponding to the two types of crowns. These groups were further divided into three subgroups each to test the different luting cements. Following the cementation process and thermocycling, the specimens were immersed in a 2% methylene blue solution for microleakage evaluation. The analysis involved sectioning the teeth and examining them under a stereomicroscope. Statistical analysis, using two-way ANOVA and post hoc Dunnett T3 tests (p < 0.05), revealed significant differences in microleakage among the cements. The study found that PZCs luted with RMGIC showed the highest level of microleakage, whereas those luted with bioactive cement exhibited the lowest, positioning bioactive cement as the preferable choice for minimizing microleakage. This finding illustrates the critical importance of selecting appropriate luting cements to optimize the clinical outcomes of zirconia crown restorations in pediatric dentistry, focusing on reducing microleakage to ensure the restoration's durability and success.

Effect of magnetic resonance imaging protocol on decision-making for positioning of dental implants in edentulous cases

PURPOSE

This study aimed to assess the influence of magnetic resonance imaging (MRI) protocol on the decision-making for the positioning of dental implants in edentulous arches in comparison to planning based on cone beam computed tomography (CBCT).

MATERIALS AND METHODS

One phantom was scanned with CBCT and two MRI protocols (T1- and T2-weighted). Two calibrated examiners performed digital implant planning (coDiagnostiX, Dental Wings), considering a digital prosthetic planning and alveolar ridge surface scan. Four implants were planned for each patient dataset, and the angular deviation between the long axis of the implants and the prosthetic planning occlusal plane was measured.

RESULTS

Each examiner planned 40 implants, 12 implants with CBCT and 28 implants with MRI (16 with T1 and 12 with T2 images). Significant differences in angle deviation were observed between CBCT, T1, and T2 in the anterior region for both examiners (p = 0.009 for examiner 1 and p = 0.042 for examiner 2). Implants planned with CBCT showed significantly lower angular deviation than those based on the T1 and T2 scans for both examiners (p = 0.028 and p = 0.046 for examiner 1 and p = 0.028 and p = 0.027 for examiner 2). No significant difference in angular deviation was found between T1 and T2 for both examiners (examiner 1: p = 0.600, examiner 2: p = 0.916).

CONCLUSION

Compared to CBCT planning, the MRI protocol influenced decision-making for anterior dental implants, with angular deviations within acceptable clinical thresholds, but further studies are needed to validate these findings.

Comparing the Effects of Propofol and Thiopental on Human Renal HEK-293 Cells With a Focus on Reactive Oxygen Species (ROS) Production, Cytotoxicity, and Apoptosis: Insights Into Dose-Dependent Toxicity

OBJECTIVES

Propofol and thiopental are widely used as hypnotic, sedative, antiepileptic, and analgesic agents in general anesthesia and intensive care; however, their side effects remain unknown. They are used for long periods and at high doses for sedation in total intravenous anesthesia (TIVA) and intensive care units. Long-term and high-dose use of these drugs can lead to accumulation in plasma and tissues, resulting in high drug concentrations and increasing the risk of potential toxicity (e.g., nephrotoxicity). In our study, the cytotoxic and apoptotic effects of propofol and thiopental on kidney cells (HEK-293) and their effects on the formation of reactive oxygen species (ROS) when used in high doses were investigated and compared in vitro.

MATERIALS AND METHODS

The half-maximal inhibitory concentration (IC50) of each drug in HEK-293 cells was determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. The apoptotic effects were assessed at two different doses of each drug using the annexin V method. Morphological examinations were conducted using the acridine orange/ethidium bromide method, and intracellular ROS levels were determined by flow cytometry.

RESULTS

The IC50 values of propofol and thiopental for HEK-293 cells were 206.59 μg/ml and 109.68 μg/ml, respectively. Compared to the control group, thiopental at ≥25 μg/ml and propofol at ≥50 μg/ml exhibited cytotoxicity. Additionally, propofol exhibited significantly lower cytotoxic effects than thiopental did.

CONCLUSION

Our study showed that both propofol and thiopental exerted significant cytotoxic effects on HEK-293 cells at concentrations exceeding clinical levels, primarily by increasing intracellular ROS levels and inducing apoptosis. Future research in this area will deepen our understanding of these mechanisms and improve patient safety in clinical anesthesia practice.

Influence of limited mouth opening in children on intraoral scanning accuracy: An in vitro study

BACKGROUND

Although intraoral scanning is highly reliable, little is known about its accuracy in young children with limited mouth-opening ability.

AIM

To determine the accuracy of intraoral scans based on the degree of mouth opening.

DESIGN

To simulate mouth opening in children with primary dentition, three groups (n = 5 per group) were allocated by maximum mouth opening of 30, 37 and 40 mm. After the primary dentition model was connected to a dental phantom, intraoral scanning was performed using iTero and TRIOS4. The scanned files were digitally evaluated. Root mean square values were calculated to assess trueness and precision.

RESULTS

iTero showed deviations of three-dimensional trueness of 0.067 ± 0.008, 0.063 ± 0.001 and 0.065 ± 0.005 mm, and TRIOS4 of 0.07 ± 0.002, 0.064 ± 0.003 and 0.066 ± 0.002 mm in the 30, 37 and 40 mm groups, respectively. There were no significant differences in either mouth opening (p > .017) or the intraoral scanners (p > .05). The same statistical results were obtained for precision, with the exception of the 30 mm of mouth opening.

CONCLUSIONS

Within the limits of this study, limited mouth opening hardly influenced the accuracy of intraoral scanning.

Enhancing scanning accuracy of digital implant scans: A systematic review on application methods of scan bodies

STATEMENT OF PROBLEM

Scan bodies play a crucial role in the accuracy of digital implant scans by serving as implant-positioning transfer devices. Previous literature has demonstrated the effects of scan body characteristics on the accuracy of digital implant scans. However, the optimal application methods of scan bodies to enhance scanning accuracy remain unclear.

PURPOSE

The purpose of this systematic review was to determine the optimal application methods of scan bodies to enhance the accuracy of digital implant scans.

MATERIAL AND METHODS

An electronic search was conducted by using the PubMed (MEDLINE), Web of Science, Cochrane Library, and Embase databases from November 2018 to 2023. Relevant references from the included studies were further screened manually for eligibility. Following the population, intervention, comparison, and outcome (PICO) criteria, a research question focused on identifying the optimal application method for effectively using scan bodies to enhance scanning accuracy was developed. Specific inclusion criteria involved in vitro and in vivo studies. The Checklist for Reporting In Vitro Studies (CRIS) guidelines were followed and the assessment of the risk of bias in the included studies was conducted.

RESULTS

Sixteen articles that met the eligibility criteria were included in this systematic review. Two studies investigated the effect of scan body bevel orientation on the accuracy of digital implant scans, and 3 examined the impact of tightening torque on scan bodies. Among the studies focusing on completely edentulous arches, 5 recommended the use of auxiliary geometric devices on the dental arch to enhance scanning accuracy. However, 2 studies reported no improvements in accuracy after splinting scan bodies with thread.

CONCLUSIONS

Different techniques for applying scan bodies, such as configuring bevel orientation, adjusting tightening torque, and attaching auxiliary geometric devices, influence the accuracy of digital implant scans. For scanning completely edentulous arches, attaching auxiliary devices to scan bodies to cover the edentulous ridge effectively enhances scanning accuracy.

Evolution of the Guided Direct Composite Resin Technique in Restorative Dentistry: A Systematic Review

OBJECTIVE

This systematic review aims to understand the limitations and benefits of the guided direct restorative technique, to optimize the final outcomes, considering the evolution from analog to digital, including planning, the diversification of guides, and the different resins employed.

METHODOLOGY

A search was conducted in the electronic databases PubMed, Cochrane, and through manual searches, initiated in May 2023 and updated in April 2024. The following search strategy was used: ((injectable composite resin) OR (direct pressed composite)) OR (3D-guided), utilizing the PICO framework.

RESULTS

Initially, 739 articles were retrieved. After applying inclusion and exclusion criteria, 33 studies were considered suitable for data extraction, including 12 in vitro studies and 21 case reports or technique descriptions. The articles focused on comparisons of techniques, flowable, heated, and conventional resins, as well as various technique reports with variations in guides, materials, and planning, potentially aiding clinicians in more effective and safer execution of this restorative technique.

CONCLUSION

The utilization of digital workflows presents greater solutions to the challenges of the guided direct restorative technique. Understanding the properties of the resins used is crucial for the results and should be chosen according to the patient's needs.

CLINICAL SIGNIFICANCE

A guided direct restorative procedure can deliver previously planned dental treatment based on individualized planning. This method ensures greater reproducibility in aesthetics and occlusion, resulting in superior quality work for the patient.

In Vitro Efficacy of Domestic Techniques for Disinfection of Toothbrushes Contaminated With Enterococcus faecalis

Introduction: Oral hygiene education for patients is fundamental in preventive-promotional dentistry. The disinfection of toothbrushes (TBs) must be integrated into this context due to their proximity to contaminant sources that make them vulnerable to cross infection in homes. The objective of this study was to compare the efficacy of domestic techniques for disinfection of TBs. Materials and Methods: We performed an in vitro study of 76 TBs contaminated with Enterococcus faecalis (Ef) ATCC 29212 subjected to different disinfection protocols: G1. Distilled water (DW; negative control; n = 8), G2. Dimethylsulfoxide (DMSO)10% (negative control; n = 8), G3. Chlorhexidine (CHX) 0.12% (positive control; n = 15), G4. 100% white vinegar (WV; n = 15), G5. Microwave (MW) at 700 W (n = 15), and G6. 200 mg/mL of certified alcoholic extract of purple garlic (GARLIC) from Arequipa (Allium sativum L; n = 15). Bacterial count was assessed by colony-forming units (CFU/mL) categorized as contamination: low (<30), medium (30-300), and high (>300). The Kruskal-Wallis test with post hoc pairs was used at a significance level of p < 0.05. Results: Efficacy against Ef showed highly significant differences between groups (p < 0.001) with lower median CFU/mL in G3 and G4 (Me = 0 [IQR (interquartile range) = 0]: low) and G5 (Me = 6000 [IQR = 45,000]: low/medium) versus negative controls (Me = 378,500 and 5,020,000 [IQR = 4,605,000 and 6,760,000]: medium/high; p ≤ 0.019). The counts of the G5 were not statistically different than G3, G4, and G6 (p > 0.06). The G6 (Me = 1,510,000 [IQR = 590,000]: medium) was inferior to G3 and G4 (p < 0.001), but similar to both negative control groups (p > 0.999). Conclusions: Disinfection of TBs with CHX, WV, and MWs produces a significant effective reduction in the count of Ef.

Investigating the impact of surface treatments on tensile bond strength between pediatric prefabricated zirconia crowns and primary maxillary incisors with various types of luting cement: an in vitro study

PURPOSE

This study aimed to evaluate the effects of two surface treatments on the tensile bond strength of prefabricated zirconia crowns (PZCs) using bioactive and resin cements.

METHODS

Forty extracted human primary maxillary incisors were prepared and divided into four groups based on surface treatment and cement type: (1) sandblast with bioactive cement, (2) sandblast with resin cement, (3) 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP) with bioactive cement, and (4) 10-MDP with resin cement. After 24 h of cementation, specimens underwent 5000 thermocycling cycles between 5 °C and 55 °C. Tensile bond strengths were measured using a universal testing machine. The data were analyzed using two-way ANOVA and Tukey's post hoc test, with significance set at p < 0.05.

RESULTS

The mean tensile bond strengths observed were 2.25 ± 1.27 MPa for sandblast with bioactive cement, 1.39 ± 0.95 MPa for sandblast with resin cement, 2.45 ± 1.15 MPa for 10-MDP with bioactive cement, and 1.68 ± 1.03 MPa for 10-MDP with resin cement. Significant improvements in bond strength were observed in the bioactive cement group treated with 10-MDP compared to those treated with sandblasting (p < 0.05). The 10-MDP treatment did not enhance bond strength for the resin cement compared to sandblasting.

CONCLUSIONS

Bioactive cement generally provides a higher tensile bond strength than resin cement. While 10-MDP treatment enhances bond strength when used with bioactive cement, it does not show a similar enhancement when used with resin cement compared to sandblasting, indicating its effectiveness is selective based on the type of cement used.

Accuracy of dynamic computer-assisted implant surgery in fully edentulous patients: An in vitro study

OBJECTIVES

To compare miniscrew versus bone tracing registration methods on dental implant placement accuracy and time efficiency in edentulous jaws using a dynamic computer-assisted implant surgery (d-CAIS) system.

METHODS

Twelve fully edentulous maxillary models were allocated into two groups: miniscrew tracing (MST) group, where registration was performed by tracing four miniscrews; and bone tracing (BT) group, where registration was conducted by tracing maxillary bone fiducial landmarks. Six implants were placed on each model using the X-Guide® d-CAIS system. Pre- and postoperative cone-beam computed tomography (CBCT) scans were superimposed to evaluate implant placement accuracy. The time required for registration and the overall surgery time were also recorded.

RESULTS

Thirty-six implants were placed in each group. The MST group showed significantly lower mean angulation deviations (mean difference (MD): -3.33°; 95 % confidence interval (CI): -6.56 to -0.09); p = 0.044), 3D platform deviations (MD: -1.01 mm; 95 % CI: -1.74 to -0.29; p = 0.006), 2D platform deviations (MD: -0.97 mm; 95 % CI: -1.71 to -0.23; p = 0.010), and 3D apex deviations (MD: -1.18 mm; 95 % CI: -1.92 to -0.44; p = 0.002) versus the BT group. The overall surgery time was similar for both groups (MD: 6.10 min.; 95 % CI: -0.31 to 12.51; p = 0.06), though bone tracing required significantly more time compared with miniscrew registration (MD: 4.79 min.; 95 % CI: 2.96 to 6.62; p < 0.05).

CONCLUSIONS

Registration with MST increases the accuracy of implant placement with a d-CAIS system in edentulous jaws compared with the BT method, and slightly reduces the overall surgery time.

CLINICAL SIGNIFICANCE

Miniscrew tracing registration improves implant placement accuracy in comparison with bone tracing registration.

Fluoride release and flexural strength of four ion-releasing restorative materials: An in vitro comparative study

Background

This study aimed to determine the fluoride release and flexural strength of four ion-releasing restorative materials.

Material and Methods

A total of 80 samples of four different materials were prepared in standardized molds: Ketac Universal, Beautifil II, Cention N, and Equia Forte Fil. The fluoride release was quantified at 1, 3, 7, 14, and 28 days post-immersion using an ion-selective electrode. The flexural strength was measured with a universal testing machine after 7 days of immersion in deionized water. A one-factor intergroup ANOVA with Welch's robust variance and Games-Howell's post hoc was employed. To compare related measures, a Friedman test with Bonferroni's adjusted post hoc was employed. The p-value was set at 0.05.

Results

At 7 days, significant differences were observed in the flexural strength of the four ion-releasing restorative materials (p<0.001). The flexural strength values from highest to lowest were as follows: Cention N (97.10 ± 4.99 MPa), Beautifil (82.77 ± 5.30 MPa), Equia Forte Fil (31.38 ± 7.68 MPa), and Ketac Universal (19.23 ± 2.94 MPa). In addition, at 3 and 7 days, the highest amount of fluoride released was observed for Cention N compared to the other ion-releasing restorative materials (p<0.05). Conversely, Beautifil II released the lowest amount of fluoride at 3, 7, 14, and 28 days (p<0.05) compared to the other ion-releasing restorative materials.

Conclusions

The immersion of all ion-releasing restorative materials in deionized water for seven days resulted in significant differences in flexural strength. Cention N had the highest value, while Ketac Universal had the lowest. All ion-releasing restorative materials released fluoride at all test times, with Ketac Universal releasing the most at 1, 14, and 28 days, and Cention N releasing it at 3 and 7 days. Beautifil II showed the lowest fluoride release at all evaluated times, exhibiting a nearly constant release over time compared to the other materials. Key words:Fluoride release, flexural strength, glass ionomer.

Does the incorporation of zinc into TiO2 on titanium surfaces increase bactericidal activity? A systematic review and meta-analysis

STATEMENT OF PROBLEM

Infections associated with bacterial biofilm formation are an important cause of early implant failure. With the growing number of antibiotic-resistant bacteria, the incorporation of zinc into TiO2 coatings of titanium implants has emerged to promote osseointegration and inhibit bacterial proliferation. However, a systematic assessment of its efficacy is lacking.

PURPOSE

The purpose of this systematic review and meta-analysis was to assess the bactericidal effect of zinc-modified TiO2 coatings on titanium or Ti-6Al-4V alloy.

MATERIAL AND METHODS

The review was structured based on the preferred reporting items for systematic reviews and meta-analyses (PRISMA) checklist and the peer review of electronic search strategies (PRESS) guidelines. The search was performed in Science Direct, SCOPUS, Web of Science, and PubMed databases, including experimental in vitro studies that used titanium or Ti-6Al-4V as a control group and performed bacterial assays. Meta-analysis was performed by using the standardized mean differences of antibacterial effects.

RESULTS

A total of 2519 articles were collected after duplicate removal. Then, eligibility criteria and a manual search were applied to select 20 studies for qualitative analysis and 16 studies for statistical analysis. The risk of bias revealed low-quality evidence. The meta-analysis showed that zinc positively affected the bactericidal activity of TiO2 coatings (-8.79, CI95%=-11.01 to -6.57, P<.001), with a high degree of heterogeneity (I2=78%). Subgroup analysis with TiO2 nanotubes produced by anodization and ZnO nanoparticles by hydrothermal synthesis reduced heterogeneity to 43%, with the removal of outliers (I2=46%), with a favorable antibacterial effect for zinc incorporation into TiO2.

CONCLUSIONS

Bactericidal activity was identified for zinc incorporated into TiO2 coatings, making it an interesting option for titanium dental implants.

Effectiveness of Papain-Based Organic Dentifrices Versus Commercial Whitening Dentifrice on Tea-Induced Tooth Stains: An In Vitro Study

INTRODUCTION

Tooth discoloration is a common issue for oral health practitioners. Whitening treatments remove surface and deep stains using either chemicals or over-the-counter products. Due to harmful chemical effects, organic whitening products are increasingly preferred. This study compared the effectiveness of organic papain-based dentifrices (Perfora Magic Teeth Whitening Serum, Gurugram, India) on tea stains to commercially available Colgate whitening dentifrices (Colgate-Palmolive, New York, NY).

METHODS

Sixty maxillary central incisors for periodontal reasons were used and divided into two groups. Each sample was soaked in freshly brewed tea for 10 minutes daily and stored in artificial saliva (Nanochemazone, Kurukshetra, India) for 24 hours. After four weeks, group 1 was treated with papain-based dentifrices, and group 2 with Colgate Visible White teeth whitening paste (CVWP) daily for four weeks. Spectrophotometric analysis (VITA Easyshade V, VITA Zahnfabrik, Bad Säckingen, Germany) was performed pre-treatment and at four weeks post-treatment. Data were compiled and statistically analyzed.

RESULTS

Compared with group 1, group 2 exhibited an optimal color change (ΔE). Statistically significant differences were observed between the mean ΔL (lightness) and Δb (blueness -b or yellowness +b) values.

CONCLUSION

CVWP showed better color achievement and stain reduction due to abrasive and peroxide components. Although Perfora Teeth Whitening Serum has low efficacy in upgrading the color of the enamel surface, it is safe for long-term use.

Comparison of the Adhesive Remnant Index and Shear Bond Strength of Different Metal Bracket Bases on Artificially Aged Human Teeth: An In vitro Study

Aim

Bond failure can compromise the clinical efficacy and duration of orthodontic treatment. A decemented bracket can lengthen the course of treatment by about 0.6 months. This study aimed to compare the adhesive remnant index (ARI) and shear bond strength of different metal bracket bases on artificially aged human teeth.

Materials and Methods

In this experimental in vitro, prospective, cross-sectional study, thirty-six human premolars were cemented with three types of metal bracket base designs: Group 1 had a laser-structured base, Group 2 had a mesh base, and Group 3 had a base with retention grooves. All groups were bonded with Transbond XT light-curing resin. Shear strength testing was performed, and the ARI was evaluated. The parametric one-factor analysis of variance test and Tukey's post hoc test were used for the comparison of shear bond strength, and the effect size was also evaluated with eta squared. In addition, the Kruskal-Wallis test was used to compare the ARI of the three groups on an ordinal scale. All statistics were set at a significance of P < 0.05.

Results

The ARI scores did not exhibit any statistically significant differences (P = 0.163). Nevertheless, the three groups exhibited statistically significant differences in shear bond strength, with an effect size of 69% (P < 0.001). The mesh base bracket had the lowest average (9.9 ± 2.6 MPa) (P < 0.001), while the laser-structured base bracket had the greatest average (19.1 ± 3.0 MPa) (P = 0.006).

Conclusion

The variation in shear bond strength was influenced by 69% due to the type of the metal bracket base used. Laser-structured and mesh-based brackets had the highest and lowest shear strength, respectively. All bases left a similar ARI on the tooth enamel.

Evaluating various properties of nanohydroxyapatite synthesized from eggshells and dual-doped with Si4+ and Zn2+: An in vitro study

Background

This study aimed to evaluate morphological, chemical and biocompatible properties of nanohydroxyapatite (N-HA) synthesized from eggshells and dual-doped with Si4+ and Zn2+.

Methods

In the current study, N-HA was synthesized from chicken eggshells using the wet chemical precipitation method and doped with Si4+ and Zn2+. The physical assessment was carried out using field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray (EDX) analysis, and X-ray diffraction (XRD) analysis. Crystal size was calculated using the Scherrer equation. Cytotoxicity was studied in vitro using the MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide) cytotoxicity assay. The optical density (OD) of each well was obtained and recorded at 570 nm for 24 h (t1), 48 h (t2), 72 h (t3), and 5 days (t4) using a microplate reader.

Results

The results of Si-Zn-doped HA showed a high specific surface area with an irregular nano-sized spherical particle structure. The atomic percentage provided the ratio of calcium to phosphate; for non-doped HA, the atomic Ca/P ratio was 1.6, but for Si-Zn-doped HA, where Zn+2 Ca and Si + replaced 4 substituted P, the atomic ratio (Ca + Zn)/(P + Si) was 1.76. The average crystal size of Si-Zn-doped HA was 46 nm, while for non-doped HA it was 61 nm. both samples were non-toxic and statistically significantly less viable than the control group After 5 days, the mean cell viability of Si-Zn-doped HA (79.17 ± 2.18) was higher than that of non-doped HA (76.26 ± 1.71) (P = 0.091).

Conclusions

The MTT assay results showed that Si-Zn-doped HA is biocompatible. In addition, it showed characteristic physiochemical properties of a large surface area with interconnected porosity.

Dentine surface modification and remineralization induced by bioactive toothpastes

OBJECTIVE

In this study, dentine surface was analysed through Environmental-scanning-electron-microscopy (ESEM) with energy-dispersive-X-ray-spectrometry (EDX) and Fourier-transform-infrared-spectroscopy (FTIR) with attenuated total-reflectance (ATR) to assess the morpho-chemical changes and variations in mineralization degree after demineralizing treatment, after five toothpastes application (HA & Citrate toothpaste, Zinc-HA toothpaste, Calcium Sodium Phosphosilicate toothpaste, Arginine & Calcium carbonate toothpaste, Colgate-Triple-Action, and Control toothpaste), after soaking in artificial saliva and after citric acid attack.

METHODS

Ca/P, Ca/N and P/N ratios were calculated from EDX atomic data to evaluate the mineralization degree of dentine surface. The IR calcium phosphate (CaP)/collagen and carbonate/collagen ratios has been evaluated to assess the remineralization changes in dentine; the carbonate/collagen IR ratio was calculated to identify the nucleation of B-type-carbonated apatite and calcium carbonate.

RESULTS

ESEM-EDX and ATR-FTIR showed residuals of toothpastes after the treatments in all cases, with a general increase in the mineralization degree after soaking in artificial saliva and a decrease after acid attack. Treatment with Arginine & Calcium carbonate toothpaste showed the highest Ca/P value after treatment (Ca/P 1.62) and acid attack (Ca/P 1.5) in confirmation, IR showed the highest amount of carbonate after treatment and soaking in artificial saliva. Arginine and calcium carbonate toothpaste and HA and citrate toothpaste remained to a higher extent on the dentine surface and revealed a higher remineralization activity. These formulations showed higher resistance to demineralization attack, as demonstrated by a higher ICaP/IAmide II intensity ratio than those obtained after EDTA treatment.

CONCLUSIONS

Toothpastes that remained to a higher extent on dentine surface (arginine and calcium carbonate toothpaste in particular) were more able to promote remineralization. The formed calcium phosphate (CaPs) phase was intimately bound to dentine rather than a simple deposit.

Assessment of colour modifications in two different composite resins induced by the influence of chlorhexidine mouthwashes and gels, with and without anti-staining properties: An in vitro study

OBJECTIVES

Chlorhexidine (CHX)-based products are the most effective chemical agents used in plaque control and oral disinfection. One of their side effects is tooth and restoration staining. For this reason, CHX products with anti-discolouration systems (ADS) have been developed. The aim of this in vitro study was to compare different CHX-based products (gel and mouthwash) with or without ADS in composite colour modification.

METHODS

Two hundred specimens were created, 100 of which were made of packable composite and 100 of flowable composite. After 24 h, colour coordinates (L*, a*, b*, C*, h°) were recorded using a spectrophotometer (T0). Then, all samples were subjected to a CHX/tea staining model and immersed in human saliva for 2 min. Composite specimens were divided in 10 groups (N = 20). Control groups (PC, FC) were soaked in distilled water and test groups (PG, PGads, FG, FGads, PM, PMads, FM and FMads) were immersed in CHX-based solutions or brushed with CHX gel. Then the cycle was repeated 6 times, and colour differences (ΔEab and ΔE00) were finally calculated.

RESULTS

Through flowable composites, FC and FG showed the highest colour differences, respectively ΔEab = 3.48 ± 1.0, ΔE00 = 2.24 ± 0.6 and ΔEab = 2.95 ± 1.3, ΔE00 = 1.53 ± 0.6. In the composite groups instead, PM and PMads showed the highest colour differences, respectively ΔEab = 2.78 ± 1.3, ΔE00 = 1.94 ± 0.8 and ΔEab = 2.71 ± 1.4, ΔE00 = 1.84 ± 0.9.

CONCLUSIONS

CHX-containing products are able to cause stains on restorative composite materials. Discolouration is more likely to occur in flowable composites than packable composites, and ADS-containing products cause fewer pigmentations than CHX products without ADS. Packable composites showed more staining after mouthwash treatment, whereas flowable composites underwent higher discolouration after treatment with gels.

Tensile bond strength between paediatric prefabricated zirconia crowns and primary maxillary incisors when using various types of luting cements: an in vitro study

PURPOSE

There is limited evidence regarding the most appropriate type of luting cement for paediatric prefabricated zirconia crowns (PZCs) in primary maxillary incisors. The retention of PZCs is dependent on the bond strength of luting cement between PZCs and primary maxillary incisors. The aim of this study was to evaluate the tensile bond strengths between PZCs and primary maxillary incisors with different types of luting cements.

METHODS

Thirty freshly extracted human primary maxillary incisors were prepared and randomly divided into three groups corresponding to three luting cements: bioactive cement, resin cement, and resin-modified glass ionomer cement (RMGIC), and then restored with PZCs. Tensile bond strengths were evaluated by a universal testing machine. The results were analysed using one-way ANOVA with Tukey's post-hoc test (p < 0.05).

RESULTS

The means of the tensile bond strengths were 1.43 ± 0.85 MPa, 0.91 ± 0.63 MPa, and 0.56 ± 0.39 MPa for the bioactive cement, resin cement, and RMGIC groups, respectively. A significant difference in tensile bond strength was observed between the bioactive cement and the RMGIC group (p < 0.05) but there was no significant difference in tensile bond strength between the resin cement group and the others.

CONCLUSION

Types of luting cement influenced the tensile bond strength between PZCs and primary maxillary incisors. The bioactive cement showed higher tensile bond strength than the resin cement and RMGIC.

Material of choice for non-invasive treatment of dentin caries: An in vitro study using natural carious lesions

INTRODUCTION

In community settings with limited dental personnel and equipment, and in an era when the aerosol transmission of infectious agents is on the rise, a non-invasive approach to caries management is critical. To provide information on non-invasive material selection, the aim of this study was to compare the remineralization effect of commonly used fluoride-containing materials, adjunctive to the everyday use of fluoride toothpaste (F-toothpaste), on primary tooth natural dentin caries.

METHODS

Fifty-five specimens were randomly divided into five groups: 38% silver diamine fluoride (SDF), 5% fluoride varnish (F-varnish), glass-ionomer cement (GIC), deionized water (DW) with F-toothpaste slurry, and DW as a control group (n = 11). The lesion depth and mineral density were measured before and after bacterial pH-cycling using micro-computed tomography. The percentage of mineral density change (%MDchange) was quantified. The dependent t-test, Wilcoxon-Signed-Rank Test, and one way ANOVA with Bonferroni correction were used to analyse the data.

RESULTS

SDF application reduced lesion depth from 844.6 to 759.1 μm (p < 0.045) while increasing mineral density from 551.4 to 763.0 mgHA/cm3 (p < 0.003). Only mineral density rose from 600.2 to 678.4 mgHA/cm3 (p < 0.013) when GIC was used. The other groups showed no difference. The highest %MDchange was also found after SDF treatment (49.7%, p < 0.05), whereas GIC (17.2%, p < 0.05) presented a higher percentage than the F-varnish (2.0%), F-toothpaste (-1.1%) and no-treatment groups (-1.4%).

CONCLUSION

In this in vitro study, where the pH of cycling was almost neutral, using SDF as an adjunct to F-toothpaste resulted in the highest remineralization compared with other remineralizing materials.

Comparative evaluation of shear bond strength and penetration of self-etch sealant with and without enamel deproteinization: an in vitro study

AIM

To compare the shear bond strength and penetration ability of self-etch sealant with and without enamel deproteinization.

MATERIALS AND METHODS

A total of 37 sound extracted teeth were selected and 31 teeth were used for testing shear bond strength of self-etch sealant. For this, crowns portions of selected teeth were cut longitudinally with a diamond disc into a mesial and distal half, thereby yielding 62 samples. They were further divided into two groups; in Group 1, samples were deproteinised with 5.25% sodium hypochlorite and a sealant cylinder was built on the proximal surface. In Group 2, sealant cylinders were built without deproteinising the surface. Shear bond strength was tested using Universal Testing Machine. The remaining six teeth were used for penetration evaluation of self-etch sealant. In Group 1, the occlusal surface was deproteinised with 5.25% sodium hypochlorite and self-etch sealant was directly applied. In Group 2, sealant was applied without deproteinisation. The samples obtained after sectioning were observed under scanning electron microscope for sealant penetration. Mann-Whitney test and Chi-square analysis were utilised for statistical analysis.

RESULTS

The results showed that the shear bond strength of the two groups was statistically not significant (p = 0.23). However, the comparison of % penetration revealed a statistically significant difference between the groups (p = 0.016).

CONCLUSION

Deproteinising the enamel surface prior to application of self-etch sealant enhanced the penetration ability of the sealant but did not show any effect on shear bond strength.

Optical properties of monolithic zirconia fabricated with nanoparticle jetting

STATEMENT OF PROBLEM

Excellent optical properties are essential for esthetic dental materials. However, the translucency and color masking ability of zirconia fabricated with nanoparticle jetting (NPJ), a type of printed zirconia, are unknown.

PURPOSE

The purpose of this in vitro study was to evaluate the translucency and color masking ability of zirconia fabricated using NPJ.

MATERIAL AND METHODS

A total of 90 specimens with thicknesses of 1.5, 1.0, and 0.5 mm were fabricated using high translucent milled zirconia (HT), low translucent milled zirconia (LT), and NPJ. CIELab values (L*, a*, and b*) of the specimens over 7 backgrounds, black, white, VitaB1, VitaA2, VitaA4, gold alloy (Au), and titanium (Ti), were obtained using a spectral radiometer. The relative translucency parameter (RTP) and color difference (∆E) of specimens over VitaB1, VitaA4, Au, and Ti were determined using VitaA2 as the control with the CIEDE2000 color difference equation. The normality of the data distribution was determined using the Shapiro-Wilk test. Differences among groups were analyzed using 2-way analysis of variance and the Student-Newman-Keuls (SNK) post hoc test (α=.05). The ∆E of specimens was analyzed according to perceptibility (∆E=0.8) and acceptability (∆E=1.8) thresholds using the 1 sample t test. The correlation between RTP and ∆E and RTP/∆E and thickness was examined using the Pearson correlation analysis.

RESULTS

Statistically significant differences were observed in translucency and color masking ability among HT, LT, and NPJ (P<.05). The RTP value was the lowest for zirconia fabricated with NPJ (P<.001) and highest for HT (P<.001). Monolithic zirconia fabricated with NPJ had lower ∆E values than those of HT and LT for the same thickness and background (P<.05). A positive correlation was found in RTP and ∆E (P<.001). A negative correlation was observed in RTP and thickness (P<.001) and ∆E and thickness across a constant background (P<.001).

CONCLUSIONS

Zirconia fabricated with NPJ was less translucent and had a greater color masking ability for discolored backgrounds than HT and LT.

Restoration-repair potential of resin-modified glass ionomer cement

This in vitro study aimed to evaluate the repair bond strength of resin-modified glass ionomer cement using either the same material or a universal adhesive in the etch-and-rinse and self-etch modes plus resin composite. Twenty-four resin-modified glass ionomer cement blocks were stored in distilled water for 14 d and thermocycled. Sandpaper ground specimens were randomly assigned to three experimental groups according to the repair protocol: resin-modified glass ionomer cement (Riva Light Cure, SDI) and universal adhesive (Scotchbond Universal Adhesive, 3M Oral Care) in etch-and-rinse or self-etch modes and nanohybrid resin composite (Z350 XT, 3M Oral Care). After 24 h of water storage, the blocks were sectioned, and bonded sticks were subjected to the microtensile bond strength (μTBS) test. One-way ANOVA and Tukey's test were used to analyze the data. The failure mode was descriptively analyzed. The highest μTBS values were obtained when the resin-modified glass ionomer cement was repaired using the same material (p < 0.01). In addition, the mode of application of the universal adhesive system did not influence the repair bond strength of the resin-modified glass ionomer cement. Adhesive/mixed failures prevailed in all groups. Repair of resin-modified glass ionomers with the same material appears to be the preferred option to improve bond strength.

Unjustified use of amber necklaces for teething symptoms alleviation: Succinic acid release underperforms compared with natural skin bacteria production

BACKGROUND

There is limited evidence of succinic acid release from amber necklace that justifies its biological plausibility.

AIM

This study aimed to evaluate the release of succinic acid from Baltic amber beads in the presence of Staphylococcus epidermidis.

DESIGN

The Baltic amber beads from the necklace were stratified according to their weight (average 0.05 g ± 0.067). Subsequently, the beads (n = 8) were submerged in 0.9% buffered saline (Control) or brain-heart infusion culture medium in the presence of a commercial strain of S. epidermidis, a resident skin bacterium incubated at 37°C for 24 h or 7 days. The samples were centrifuged, and the supernatants were analyzed by 1H Nuclear Magnetic Resonance. Multivariate analyses were adopted using the sparse partial least squares discriminant analysis method (p < .05).

RESULTS

The group incubated with saline solution showed small release of succinic acid only after 7 days. In the groups with S. epidermidis, the release of succinic acid was observed in the both presence and absence of amber beads, indicating that succinic acid is a product released by bacteria.

CONCLUSIONS

It was found that amber beads do not exhibit the ability to release expressive succinic acid, especially in a short period of time, which does not justify their use in infants. The most production of succinic acid is tributed to S. epidermidis.

Influence of bottled salad dressings on the development of enamel erosion in the presence or absence of salivary pellicle - An in vitro study

Background

Acidic beverages are believed to elevate the risk of enamel surface erosion. In addition to the intake of soft drinks, the increased consumption of salad dressings has been linked to a higher prevalence of dental erosion. Therefore, the current study aimed to investigate the influence of bottled salad dressings on the development of enamel erosion in the presence or absence of pellicle through in vitro experiment.

Methods

Preliminary pH and calcium analyses of solutions were performed. Highest pH and calcium content was found for sandwich spread i.e., 4.69 and 55.4 mg/100 g grams, respectively. Eighty tooth specimens (measuring 4 × 4 × 3 mm) were prepared from extracted human premolars and randomly assigned to four groups (group 1: orange juice; group 2: eggless plain mayonnaise; group 3: sandwich spread; and group 4: thousand island dressing) with 20 samples in each group. Ten tooth specimens from each group were immersed in 20 ml of the respective solutions for 5 min (control group). The remaining ten tooth specimens from each group were submerged in 5 mL saliva vials for 3 min to facilitate salivary pellicle formation before being immersed in their respective solutions for 5 min (saliva-covered group). Pre and post-experimental assessments of enamel roughness and hardness were conducted using a surface roughness tester and Knoop Hardness indenter, respectively.

Results

Overall, enamel roughness was notably elevated in the control group, with the eggless plain mayonnaise (0.52 ± 0.38) and thousand island dressing groups (0.57 ± 0.29) showing a significant increase in surface roughness post-test (p = 0.05). Nevertheless, there was no significant difference in the enamel roughness between the groups. On the other hand, regardless of the presence/absence of the salivary pellicle, a marked decrease in enamel hardness was observed among all groups except for group 3 (sandwich spread) with a mean score of 311.5 ± 82.6 (p < 0.05).

Conclusion

A significant increase in surface roughness and reduction in enamel hardness was observed with salad dressings. However, in vitro formed salivary pellicle showed a protective effect against tooth erosion.

Evaluation of Antimicrobial Efficiency, Shear Bond Strength, and Adhesive Remnant Index of TiO2 Infiltrated Orthodontic Adhesive - An In Vitro Study

Background

Enamel demineralization is an unavoidable adverse effect encountered with bonding brackets in orthodontic therapy. Introducing nanoparticles into the composite adhesive paste can prevent enamel demineralization. Titanium dioxide (TiO2) is known to exhibit direct antimicrobial efficiency. This study aimed to assess the antibacterial efficiency and shear bond strength (SBS) of an orthodontic bonding composite infiltrated with TiO2 nanoparticles.

Materials and Methods

This in vitro study evaluated the efficiency of TiO2 nanoparticle-incorporated light-curing orthodontic composite paste (ENLIGHT, ORMCO). Twenty extracted premolars were randomly and equally allocated to the two study groups, N = 10. While a conventional composite was utilized for the bonding brackets in Group I, a TiO2-incorporated composite was used in Group 2. The adhesive remnant index (ARI) scores given by Artun and Bergland et al. and SBS were determined. Furthermore, the antimicrobial efficiency was estimated using the minimum inhibitory concentration (MIC)/minimum bactericidal concentration (MBC) and agar well diffusion assay for six composite disc specimens. The results were statistically analyzed using the chi-square test and Student's t test, at P < 0.05.

Results

After 24 h of curing, no statistical mean difference was observed between the two groups in terms of ARI or SBS scores (P > 0.05). However, there was a significant increase in the antimicrobial efficiency of Group II when compared with Group I (P < 0.05).

Conclusion

TiO2 nanoparticle-incorporated orthodontic composites improve the antimicrobial efficiency with no significant change in the SBS. The ARI scores indicate the presence of 50% remnant orthodontic composite on the tooth enamel surface post debonding.

Accuracy in osteotomy drilling using a new universal and disposable drill-stop device for dental implant drills: an in vitro study using a bovine rib model

BACKGROUND

This study aimed to evaluate the surgical accuracy of a new universal disposable stop system for implant drills (FCA Universal Drill Stop).

MATERIAL AND METHODS

A total of 60 bovine ribs were included in this in vitro study. The ribs were randomized into three study groups (n=20 ribs per group). In each study group (Group1: drills without stop or control group, Group 2: prefabricated drills with stop or gold standard group, and Group 3: drills with FCA Universal Drill Stop) a total of 100 osteotomies were performed with implant drills in each group, following the drilling sequence for the placement of a dental implant of 10 mm length and 4 mm diameter. The accuracy of the depth of the osteotomies was quantified clinically (with periodontal probe) and radiologically, using ImageJ version 1.48v software.

RESULTS

The order of highest to lowest accuracy (clinical and radiological) in the depth of osteotomies was: FCA Universal Drill Stop> prefabricated drills with a stop>drills without stop, with statistically significant differences being observed between both systems with stop with respect to the control group, although not between them.

CONCLUSIONS

The new universal disposable stop system for implant drills, offers similar accuracy to prefabricated drills with stop, with both systems being much more accurate than implant drills without stop. Although this experimental evaluation showed favourable results, further clinical studies are necessary.

Effectiveness of KTP lasers in tooth bleaching, by comparing tooth color change after bleaching with KTP, Nd:YAG, Er:YAG, and diode laser system: A systematic review

This systematic review evaluated the role of Potassium-titanyl-phosphate (KTP) lasers in dental bleaching by comparing tooth color change and rise in intrapulpal temperature after bleaching with KTP, Neodymium-doped yttrium aluminum garnet (Nd:YAG), Er:YAG, and diode laser system. Following were the inclusion criteria: in vitro studies in English available in full text. Articles published between 2000 and 2021 were selected. The search for was conducted on PubMed, Cochrane library/CENTRAL, Wiley online library, ProQuest, Science Direct, and Hand searching/specialized registers. Keywords were used: "Lasers" [Mesh] and "Tooth bleaching" [Mesh] using Boolean operators. A total of four articles fulfilled the inclusion criteria. The quality assessment of studies included was undertaken independently as part of data extraction process. KTP lasers demonstrated more effectiveness in attaining color change in stained teeth and showed the lowest rise in intrapulpal temperature. Based on the data obtained in the present review, the choice of bleaching treatment is directly related to the type of discoloration, activation of the bleaching agent, and esthetic requirement. Although all bleaching procedures were effective in color change, the KTP laser showed better results when compared to other laser activation. The bleaching treatment protocol is directly related to the type of discoloration, activation of the bleaching agent, and esthetic requirement. It has been demonstrated that a faster change in color can be obtained when bleaching is performed in combination with a light source, i.e., power bleaching aiming for a more in-depth change of color.

Effect of temperature on rehydration and fracture resistance of reattached tooth fragments after crown fracture: An in vitro study

BACKGROUND

Uncomplicated crown fractures of maxillary anterior teeth are common dental injuries, and the bonding of fractured fragments is recommended for management. Rehydration of fragments improves bonding and fracture resistance. Therefore, the aim of this study was to compare the fracture resistance of the reattached tooth fragment of the incisor crown after rehydration using either a steamer or a humidifier.

MATERIALS AND METHODS

Bovine teeth were used as a model. Fractured fragments were divided into three groups: Group I (no rehydration), Group II (rehydration by humidifier), and Group III (rehydration by steamer). Fragments were reattached using a standard bonding protocol. Fracture resistance was tested using a universal testing machine. Statistical analysis was performed using analysis of variance and Chi-square tests.

RESULTS

The force required to fracture the reattached fragments was significantly higher in Group II (humidifier) compared to Group I (no rehydration) (P = 0.005). Group III (steamer) had a force value similar to Group I, indicating no significant improvement in fracture resistance with steamer rehydration. The temperature inside the steam-based chamber reached an average of 95.7°C with 95% humidity, whereas the conventional humidification chamber had an average temperature of 39.2°C and 84% humidity.

CONCLUSION

Within the limitations of the present study, the rehydration protocol using a steam-based chamber was found to have a significantly lower force required to fracture the reattached fragments as compared to humidifier-based chamber. This was not significantly different from the fragments which were reattached without rehydration.

Effect of Ultraviolet-C Light Exposure Time on the Dimensional Stability of Addition Silicone Dental Impressions: An In Vitro Study

AIM

To compare the effect of different ultraviolet-C (UV-C) light exposure times on the dimensional stability of addition silicone dental impressions.

MATERIALS AND METHODS

The dimensional stability of the addition silicone dental impressions was assessed by measuring specific dimensions on dental casts that were recovered from an upper acrylic resin model of dental implants. The impressions were reproduced using a customized tray adapted in a three-point simplex dental articulator permitting only opening and closing movements. Addition silicone dental impressions were divided into five groups (N = 12) according to the UV-C light exposure time. Group A was untreated; group B received 10 minutes; group C, 20 minutes; group D, 30 minutes; and group E, 40 minutes. All the impressions were poured with type IV dental stone and the internal edges of the upper silicone retainers of impression copings were used as five reference points (E, D, C, B, and A) to determine six linear measurements between ED, CB, EA, AD, EB, and CD points using a traveling microscope of 0.001 mm accuracy. One-way analysis of variance (ANOVA) was used for the statistical analysis (p < 0.05).

RESULTS

Expansion and contraction were noted among ED, CB, EA, and EB measurements, whereas only expansion was noted among AD and CD measurements. The ANOVA analysis showed there was no significant difference in the arithmetic means for the measurements between and within group A and the other groups (p > 0.05).

CONCLUSION

The UV-C light exposure time of 10, 20, 30, and 40 minutes did not have any negative effect on the dimensional stability of the addition silicone dental impressions evaluated.

CLINICAL SIGNIFICANCE

In the daily routine dental practice, dental impressions need to be washed and disinfected immediately after making to prevent cross-infections. The UV-C light has been proposed as a promising method for disinfection, but only a few studies have been published about its effect on the dimensional stability of dental silicones. How to cite this article: Bravo-Cueto AG, Tinedo-López PL, Malpartida-Carrillo V. Effect of Ultraviolet-C Light Exposure Time on the Dimensional Stability of Addition Silicone Dental Impressions: An In Vitro Study. J Contemp Dent Pract 2024;25(6):507-513.

Effect of mutanase and dextranase on biofilms of cariogenic bacteria: A systematic review of in vitro studies

Matrix-degrading enzymes are promising non-biocidal adjuncts to dental biofilm control and caries prevention. By disrupting the biofilm matrix structure, enzymes may prevent biofilm formation or disperse established biofilms without compromising the microbial homeostasis in the mouth. This study reviewed whether treatment with mutanase and/or dextranase inhibits cariogenic biofilm growth and/or removes cariogenic biofilms in vitro. An electronic search was conducted in PubMed, EMBASE, Scopus, Web of Science, Cochrane, and LIVIVO databases. Manual searches were performed to identify additional records. Studies that quantitatively measured the effect of mutanase and/or dextranase on the inhibition/removal of in vitro cariogenic biofilms were considered eligible for inclusion. Out of 809 screened records, 34 articles investigating the effect of dextranase (n = 23), mutanase (n = 10), and/or combined enzyme treatment (n = 7) were included in the review. The overall risk of bias of the included studies was moderate. Most investigations used simple biofilm models based on one or few bacterial species and employed treatment times ≥30 min. The current evidence suggests that mutanase and dextranase, applied as single or combined treatment, are able to both inhibit and remove in vitro cariogenic biofilms. The pooled data indicate that enzymes are more effective for biofilm inhibition than removal, and an overall higher effect of mutanase compared to dextranase was observed.

Development and validation of a risk-of-bias tool for assessing in vitro studies conducted in dentistry: The QUIN

STATEMENT OF PROBLEM

Systematic reviews and meta-analyses have emerged as forerunners of evidence-based dentistry, but assessing the quality of the available research is essential so that it can be applied to clinical practice. While a wide variety of risk-of-bias tools are available, each specifically developed for different study designs, a comprehensive tool exclusively framed to assess the quality of in vitro dental studies is lacking.

PURPOSE

The purpose of this study was to develop and validate a tool to evaluate the quality and risk of bias of in vitro dental studies.

MATERIAL AND METHODS

A Delphi panel was established to conceptualize and develop the Quality Assessment Tool For In Vitro Studies (QUIN Tool). The tool was evaluated by using content validity and reliability testing methods.

RESULTS

The QUIN Tool includes 12 points along with scoring and grading options to allow clinicians to evaluate the quality of in vitro studies. This tool shows good content validity and reliability.

CONCLUSIONS

The QUIN Tool is user-friendly, efficient, and effective for evaluating the risk of bias of in vitro studies.

Medicinal plants with promising antileishmanial activity in Ethiopia: A systematic review and meta-analysis

INTRODUCTION

Toxicity and resistance to chemotherapy used to treat leishmaniasis are increasing. Research on natural plant compounds has revealed their antileishmanial effects on certain Leishmania organisms. This review aimed to estimate the pooled IC50 values of medicinal plants with promising antileishmanial activity in Ethiopia.

METHODS

A systematic literature search was conducted using Science Direct, PubMed, Cochrane Library, and Google Scholar to locate potential studies. Studies published in peer-reviewed journals and gray literature in university repositories before April 1, 2022, which included a full-length study reporting the half-maximal inhibitory concentration (IC50) of Ethiopian medicinal plants that were written in English were included. Conference proceedings, review articles, letters to the editor, and correspondence were excluded. The quality of the included studies was assessed using the GIVIMP critical appraisal tools. Heterogeneity between studies was verified using Cochrane Q test statistics and I2 test statistics, and the effects were checked using Egger statistical test at a level of significance. A random-effects model was used to estimate the pooled IC50 of the medicinal plants.

RESULTS

Six articles that were conducted in Ethiopia that fulfilled the inclusion criteria, with a total of 62 in vitro experiments, were reviewed. The aggregated mean IC50 for medicinal plants in Ethiopia was 16.80 (95% CI: 12.44, 21.16) and 13.81 (95% CI: 13.12, 14.50) µg/mL for antipromastigote and antiamastigote activity, respectively. Aqueous was the significant preparation with IC50 of 0.53 (0.34, 0.73) µg/mL against promastigote and 0.98 (0.20, 1.76) µg/mL against the amastigote stage.

DISCUSSION

This review indicated that the pooled mean of IC50 for Ethiopian medicinal plants against promastigotes and amastigotes was relatively low and showed better efficacy. This strongly suggests the need to focus on antipromastigote and antiamastigote medicinal plants in Ethiopia for the development of antileishmanial drugs. It is necessary to identify their active components, and their potential toxic effects can lead to the production of well-tolerated and safe drugs for leishmaniasis. The high heterogeneity is the limitation of this study.

REGISTRATION

The review has been registered at Prospero with identification number CRD42022343543.

Equivalence study of the resin-dentine interface of internal tunnel restorations when using an enamel infiltrant resin with ethanol-wet dentine bonding

This preregistered ex vivo investigation examined the dentinal hybrid layer formation of a resinous infiltrant (Icon), with reference to both thickness (HLT) and homogeneity when combined with modified tunnel preparation (occlusal cavity only) and internal/external caries infiltration. The adhesives Syntac and Scotchbond MP were used as controls (Groups 1 and 3) or in combination with Icon (Groups 2 and 4). A split-tooth design using healthy third molars from 20 donors resulted in 20 prepared dentine cavities per experimental group. The cavity surfaces (n = 80) were etched (37% H3PO4), rinsed, and air-dried. Rewetting with ethanol was followed by application of the respective primers. After labeling with fluorescent dyes, either Syntac Adhesive/Heliobond or Scotchbond MP Adhesive was used alone or supplemented with Icon. HLT, as evaluated by scanning electron microscopy, did not significantly differ (P > 0.05), and confocal laser scanning microscopy revealed homogeneously mixed/polymerized resin-dentine interdiffusion zones in all groups. Icon can be successfully integrated into an ethanol-wet dentine bonding strategy, and will result in compact and homogeneous hybrid layers of comparable thickness considered equivalent to the non-Icon controls, thus allowing for preservation of the tooth's marginal ridge and interdental space in the case of internal/external infiltration of proximal caries.

Effect of Polywave and Monowave Light Curing Units on the Microtensile Bond Strength and Failure Types of Different Bulk-Fill Resin Composites: An in vitro Study

Aim

This study aimed to evaluate the effects of polywave and monowave light-emitting diode curing units on the microtensile bond strength and failure types of three bulk-fill resin composites.

Materials and Methods

This in vitro experimental study was performed on 180 microbars obtained from human third molars and were distributed into 12 groups according to the type of bulk-fill resin composite and the light-curing unit. Third molars were restored using Filtek One Bulk Fill Restorative, Tetric® N-Ceram Bulk Fill, and Opus Bulk Fill resin composites was light-cured with Elipar Deep Cure L and Valo in three modes: standard, high power, and extra power. Subsequently, microtensile analysis was carried out with a universal testing machine and the type of failure with an optical stereomicroscope. For statistical analysis, the Kruskal-Wallis H-test was used, with the Bonferroni post hoc test and Fisher's exact test, considering a significance of p<0.05.

Results

There were significant differences in the microtensile bond strength between the Filtek One Bulk Fill restorative and Opus Bulk-Fill (p = 0.042) when light was cured with the polywave unit at standard power. On the other hand, the Filtek One Bulk Fill Restorative and Opus Bulk Fill resins showed significant differences in microtensile bond strength when light was cured with the monowave unit compared with the polywave unit (p<0.05).

Conclusion

The presence of alternative photoinitiator systems that are more reactive than camphorquinone produced higher microtensile bond strength in Tetric N-Ceram Bulk Fill and Opus Bulk Fill resins when light-cured with a high and standard polywave unit, respectively, compared to Filtek One Bulk Fill resins. Finally, Tetric N-Ceram Bulk Fill and Opus Bulk Fill resins had the highest percentage of mixed failures, while Filtek One Bulk Fill resin had adhesive failures, which was related to its lower microtensile bond strength.

Insertion torque, flexural strength and surface alterations of stainless steel and titanium alloy orthodontic mini-implants: an in vitro study

OBJECTIVE

This study aimed to compare the insertion torque (IT), flexural strength (FS) and surface alterations between stainless steel (SS-MIs) and titanium alloy (Ti-MIs) orthodontic mini-implants.

METHODS

Twenty-four MIs (2 x 10 mm; SS-MIs, n = 12; Ti-MIs, n = 12) were inserted on artificial bone blocks of 20 lb/ft3 (20 PCF) and 40 lb/ft3 (40 PCF) density. The maximum IT was recorded using a digital torque meter. FS was evaluated at 2, 3 and 4 mm-deflection. Surface topography and chemical composition of MIs were assessed by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). General linear and mixed models were used to assess the effect of the MI type, bone density and deflection on the evaluated outcomes.

RESULTS

The IT of Ti-MIs was 1.1 Ncm greater than that obtained for the SS-MIs (p= 0.018). The IT for MIs inserted in 40 PCF test blocks was 5.4 Ncm greater than that for those inserted in 20 PCF test blocks (p < 0.001). SS-MIs inserted in higher density bone (40 PCF) had significantly higher flexural strength than the other groups, at 2 mm (98.7 ± 5.1 Ncm), 3 mm (112.0 ± 3.9 Ncm) and 4 mm (120.0 ± 3.4 Ncm) of deflection (p< 0.001). SEM evidenced fractures in the Ti-MIs. EDS revealed incorporation of 18% of C and 2.06% of O in the loaded SS-MIs, and 3.91% of C in the loaded Ti-MIs.

CONCLUSIONS

Based on the findings of this in vitro study, it seems that SS-MIs offer sufficient stability and exhibit greater mechanical strength, compared to Ti-MIs when inserted into higher density bone.

Antifungal Activity of Morinda citrifolia Methanolic Extract against Candida albicans: An In Vitro Study

Aim

Natural medicine used as an alternative and/or complementary treatment to counteract diseases is of great importance in public health. Therefore, the purpose of the present study was to assess the in vitro antifungal activity of Morinda citrifolia methanolic extract of peel, pulp, and seed against Candida albicans.

Materials and Methods

The present study was experimental in vitro and cross-sectional. Eight replicates were prepared in Sabouraud dextrose agar with five wells each, where 0.12% chlorhexidine, distilled water, and methanolic extract of seed, peel, and pulp of Morinda citrifolia fruit were placed at concentrations of 10,690, 8,270, and 6,430 mg/mL, respectively, to evaluate sensitivity according to Duraffourd's scale. In addition, the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) were determined by dilution and agar seeding method. Statistical analysis was performed by analysis of variance (ANOVA) and Tukey's post hoc test, considering a significance level of P < 0.05.

Results

The inhibition halos of Morinda citrifolia methanolic extract of seed, peel, and pulp against Candida albicans measured on average 15.94, 11.94, and 11.56 mm, respectively. The MIC of seed, peel, and pulp extract were 1366.25, 2067.5, and 1607.5 mg/mL respectively, whereas the MFC for seed, peel, and pulp extract were 2672.50, 2067.5, and 3215 mg/mL, respectively. Moreover, seed extract presented significantly higher antifungal activity than peel and pulp (P < 0.001).

Conclusions

Morinda citrifolia methanolic extract of peel, pulp, and seed showed fungistatic and fungicidal effect against Candida albicans, being this very sensitive to seed extract with a MIC of 1366.25 mg/mL and a MFC of 2672.5 mg/mL, which allows recommending the development of effective pharmacological formulations for the control of candidiasis.

Comparative evaluation of the accuracy of two electronic apex locators in detecting simulated incomplete vertical root fractures: An in vitro stereomicroscopic study

Aim

The aim of this study was to compare the accuracy of two different electronic apex locators (EALs) in detecting simulated incomplete vertical root fractures (VRFs).

Materials and Methods

Thirty freshly extracted single-rooted teeth were randomly divided into three groups of 10 teeth each labeled as Groups A, B, and C. Incomplete VRFs were simulated in the coronal, middle, and apical one-third of the roots for Groups A, B, and C, respectively. The teeth were embedded in alginate mold and fracture location was determined with Root ZX and Propex EALs for each sample and each group. To calculate the actual length (AL), each sample was sectioned at the upper level of the vertical fracture, and the length was measured by setting the stopper of the #10 K file under a stereomicroscope at ×30 magnification. The electronic lengths and ALs were compared using computer software, and the results were analyzed using SPSS 28.0 at a 95% confidence level.

Results

No significant differences were seen in the accuracy of the two EALs when compared with ALs. Root ZX showed significantly longer measurements than ALs in groups B and C.

Conclusion

The tested EALs showed low accuracy (20%) in detecting simulated incomplete VRFs with a tendency for longer measurements compared to ALs.

Effect of different brushing parameters on erosive tooth wear in primary bovine enamel and dentin

This in-vitro study aimed to analyse the effect of brushing and different brushing parameters (kind of toothpaste, kind of toothbrush, brushing force) on erosive tooth wear of primary bovine enamel and dentin. Specimens were prepared from primary bovine enamel or dentin (each group n = 12) and cyclically eroded (6 × 60 s/d, citric acid, pH 2.4) and brushed with children's toothbrushes (2 × 15 s/d) over 5 days. The brushing parameters under investigation were: toothpaste (fluoridated, fluoride-free), toothbrush (manual; rotating-oscillating and sonic, each at two different activation modes) and brushing force (1 N, 2 N). Specimens that were only eroded and not brushed served as controls. Enamel and dentin wear was quantified using widefield confocal microscopy. Statistical analysis was performed using three- and one-way ANOVAs followed by Scheffe's (enamel) or Tamhane's (dentin) post-hoc tests (p < 0.05). Brushing with the fluoridated toothpaste was able to significantly reduce erosive wear in enamel (by 15 to 37%, 6 of 10 groups) and in dentin (by 58 to 72%, all groups), while brushing with the fluoride-free toothpaste was not different from the controls. Considering the kind of toothpaste and brushing force, slight differences between the toothbrushes were observed in enamel, but not in dentin. Within the same toothbrush and activation mode, almost no differences between 1 and 2 N brushing force were detected. In conclusion, erosive tooth wear on primary bovine dental hard tissue mainly depends on the kind of toothpaste, rather than on the kind of toothbrush and the brushing force.

Effect of a novel mesh design and the sandblasting technique on the bond strength of computer-designed and three-dimension laser printed resin bonded bridges: an in vitro study

Resin-bonded bridges (RBBs) are a minimally invasive and aesthetically pleasing treatment modality. However, their frequent failure has posed challenges for both dental professionals and patients. This necessitates the exploration of innovative strategies to enhance the longevity of RBBs. This study aimed to assess the bond strength of a mesh bridge fabricated using computer-aided design and three-dimensional (3D) printing technology in comparison to the traditional aluminum oxide sandblasting method. A total of 48 lower incisors were embedded in acrylic bases according to a standardized computer-generated model to receive 24 metal RBBs. The two groups underwent distinct metal surface treatments: the 3D mesh novel design and sandblasting with aluminum oxide particles sized at 250.00 µm. The bond strength of the bridges was evaluated, and statistical analysis was performed using the independent samples t-test with a significance level set at α = 0.05. The findings revealed a significant difference between the two methods (p < 0.001). The 3D mesh design exhibited a mean bond strength of 387.89 ± 24.15 N, while the sandblasting technique yielded a mean value of 161.46 ± 31.25 N. In summary, the 3D mesh design substantially enhanced the bond strength of RBBs compared to the traditional sandblasting technique.