Frontiers in Dentistry
Volume:20 Issue: 1, Mar 2023

The focused question of this systematic review was “does hyaluronic acid (HA) injection in areas of interdental papillary deficiency reduce black triangles?”

A systematic literature search was performed to find clinical studies on human patients with a minimum of 6-month follow-up, published in English from 2005 to May 2020. There were two outcome variables: black triangle area (BTA) change after treatment at different measurement time points compared with baseline, and patient reported outcome measures (PROMs), when available.

Of eight eligible articles (2 randomized clinical trials (RCTs) and 6 non-randomized, non-placebo controlled clinical studies), seven reported that HA injections had a positive impact on reduction of BTA and subsequent papillary augmentation. Six studies were included in meta-analysis and showed that the intervention led to a pooled reduction percentage of 57.7% in BTA after 6 months. Although there were clinical diversities between the studies, all the studies applied the same concentration of HA (approximately 2%), 2-3 mm apical to the papilla tip in several intervals. Some degrees of relapse were reported in some studies.

Within the limits of this study, this systematic review and meta-analysis showed that HA injection can serve as an efficient minimally-invasive treatment for small interdental papillary deficiencies. It is essential to conduct further randomized clinical studies with prolonged follow-ups in order to support this conclusion.

This paper presents a systematic review and meta-analysis of the effect of different finishing and polishing (F/P) systems on surface roughness (SR) and microbial adhesion to bulk fill (BF) composites.

An electronic search of 3 databases (the National Library of Medicine [MEDLINE/PubMed], Scopus, and ScienceDirect) was conducted. Only in vitro studies that evaluated SR and microbial adhesion to BF composites were included. The included studies were individually evaluated for the risk of bias following predetermined criteria. A meta-analysis of the reviewed studies was conducted to compare the SR values of both Filtek Bulk Fill and Tetric EvoCeram Bulk Fill with and without F/P using the Comprehensive Meta-Analysis software.

A total of 12 studies fulfilled the inclusion criteria. The meta-analysis showed no significant difference between Filtek Bulk Fill and Tetric EvoCeram Bulk Fill without F/P or after F/P using multi-step systems. Different F/P systems affected the SR values, on the other hand, did not affect microbial adhesion values.

Both Filtek Bulk Fill and Tetric EvoCeram Bulk Fill had comparable roughness results. Multi-step systems may be preferable for F/P of BF composites.

The combination of mineral trioxide aggregate (MTA) and 2% chlorhexidine (CHX) has been recently introduced as an intracanal medicament. The aim of this study was to evaluate the potential cytotoxic effects of MTA mixed with 2% chlorhexidine gel on human periodontal ligament stem cells (PDLSCs) and compare it with other common endodontic regeneration medicaments.

Minimum inhibitory concentration and minimum bactericidal concentration of six experimental groups against Enterococcus faecalis was determined. The study groups consisted of RetoMTA mixed with 2% chlorhexidine gel (MTA+CHX), calcium hydroxide (CH), CH mixed with CHX gel, two concentrations of double antibiotic paste, and 2% CHX. The direct cytotoxic effect of minimum bactericidal concentration was evaluated by MTT on PDLSCs on days 1, 3, and 7. One-way ANOVA and post hoc tests were used for data analysis (P<0.05).

The viability of cells treated with MTA+CHX decreased significantly over time (P<0.05) making this group the most cytotoxic intracanal medicament on the 3rd and 7th days of treatment. On day one, the highest viability percentage was detected in the CH+CHX group followed by the CHX group. On day 3, CH+CHX and CHX groups displayed the highest viability percentage. On day 7, the highest viability was observed in the CHX group, which showed no significant difference with the control group (P=0.12).

Regarding the antimicrobial potency of intracanal medicaments at minimum bactericidal concentration levels, CHX gel appears to be the least cytotoxic drug, while MTA+CHX shows the highest reduction in viability percentage

This study assessed the fracture resistance of zirconia crowns with four framework designs, fabricated by computer-aided design/computer-aided manufacturing (CAD/CAM) technology.

In this experimental study, a maxillary central incisor was prepared and scanned with a CAD/CAM scanner, and 40 frameworks with 4 designs (N=10) were fabricated as follows: simple core, dentine core with a design similar to dentine, 3mm trestle design collar in the lingual aspect with proximal buttresses, and monolithic or full-contour. After porcelain applying and 20h immersion in distilled water (37°C), crowns were cemented on metal dies using zinc phosphate cement. Fracture resistance was measured by a universal testing machine. Data were analyzed with one-way ANOVA (alpha=0.05).

Fracture resistance was maximum in the monolithic group, followed by the dentine core, trestle design, and simple core groups, respectively. The mean fracture resistance of the monolithic group was significantly higher than that of the simple core group (P<0.005).

Zirconia restorations with frameworks that provided higher and more support for porcelain, showed increased fracture resistance

The present study aimed to evaluate the efficacy of ginger essential oil spray for elimination of Candida albicans (C. albicans) adhering to self-cure acrylic plates.

In this experimental study, 120 self-cure acrylic discs were contaminated with C. albicans and randomly divided into four main groups: exposure to ginger essential oil, nystatin (positive control), distilled water (negative control), and no exposure. The minimum inhibitory concentration (MIC) of ginger oil and nystatin was determined by the microdilution test. The stability of C. albicans was determined by culturing the samples of treated acrylic plates and comparing the mean number of remaining colonies. Data were analyzed using the Kruskal-Wallis test followed by Dunn test with Bonferroni correction.  P<0.05 was considered significant

The MIC of ginger essential oil and nystatin was found to be 1560µg/mL and 4µg/mL, respectively. The differences between the mean count of C. albicans colonies before (10175±10730.25) and after the exposure to ginger essential oil (542.86±464.81) and nystatin (257.14±247.67) was statistically significant (P<0.001). The mean number of C. albicans colonies after spraying with nystatin was not significantly different compared with ginger essential oil (P=0.204). The efficacy of nystatin and ginger essential oil at each time was significantly more than distilled water (P<0.001). At 10 and 15min, there was no significant difference between nystatin and ginger essential oil groups (P=0.05).

Ginger essential oil spray was found to be a simple and effective method for elimination of C. albicans adhering to acrylic discs.

The purpose of this randomized parallel clinical trial was to assess and compare the efficacy of 97% Aloe Vera (AV) gel and 94.7% AV juice against an active control (0.05% Clobetasol Propionate) in the treatment of oral lichen planus (OLP).

Age and sex matched patients with histologically proven OLP were divided into two groups. One group received 97% AV gel for topical application and 10ml 94.7% AV juice to consume twice daily. The active control group received topical 0.05% Clobetasol Propionate ointment twice daily. Treatment lasted two months followed by four months of observation. Monthly evaluation of various clinical features of OLP was done using the OLP disease scoring criteria. Burning sensation was evaluated using Visual Analog Scale (VAS). Mann Whitney–U (followed by Bonferroni adjustment) and Wilcoxon’s signed-rank tests were used for intergroup and intragroup comparisons, respectively. Interclass correlation-coefficient test was applied to assess the intra-observer variation (P<0.05).

In total, 41 females and 19 males participated in this study. The most common site was the buccal mucosa followed by the gingivobuccal vestibule. The reticular variant was most frequently encountered. Wilcoxon’s signed-rank test showed significant differences in both groups between baseline and end-of-treatment for VAS, site-score, reticular/plaque/papular score, erosive/atrophic score and OLP disease score (P<0.05). Mann–Whitney revealed significant difference between both groups in the 2nd, 3rd and 4th months (P<0.0071).

Clobetasol Propionate is more effective for OLP management but in our study AV proved to be a safe treatment alternative for OLP management.

This study was performed to find the most common types of maxillofacial fractures and their management in 3 to 18-year-old individuals referred to the Department of Oral and Maxillofacial Surgery at Shariati Hospital in Tehran, during a 9-year period.

This retrospective study evaluated the records of 319 patients with maxillofacial fractures between 2012-2020, ranging in age from 3 to 18 years. Data regarding the etiology and location of the fracture, age, gender, and treatment approach were retrieved from the archival records and analyzed.

A total of 319 patients were included in the study, out of which, 255 (79.9%) were males and 64 (20.1%) were females. Motor-vehicle accidents were the most common cause of trauma (N=124, 38.9%). We recorded 605 fractures and among them, the parasymphysis (N=131, 21.6%) was the most common site of isolated fractures. Type of treatment varied depending on the fracture type and degree of displacement of the broken segments. It consisted of open reduction and internal fixation, and closed reduction procedures, which included the use of arch bars, ivy loops, lingual splints, and circummandibular wirings.

Analysis of the results revealed that the severity of injury increased with age. Older individuals had higher a number of fracture sites and experienced greater displacement of the broken segments.

Age estimation is a crucial aspect of forensic odontology, and the Tooth Coronal Index (TCI) has been widely used for forensic purposes in determining age. The aim of this research was to evaluate the effectiveness of TCI in age estimation.

A retrospective study was conducted, and TCI was calculated for the mandibular first premolar in 700 digital panoramic radiographs. Age was divided into five groups: 20-30 years, 31-40 years, 41-50 years, 51-60 years, and >61 years. Bivariate correlation was used to establish the relationship between TCI and age. Linear regression was calculated for the different age groups and genders. Inter-observer reliability and agreement were assessed using one-way ANOVA. P-values less than 0.05 were considered statistically significant.

Comparison of the mean difference from actual age showed underestimation in males aged 20-30 years and overestimation in males over 60 years of age. The least difference between actual and calculated age was found in females aged 31-40 years. Inter-age comparison using ANOVA for females demonstrated a statistically highly significant difference from actual age in all age groups (P<0.01), with the highest mean in females aged 51-60 years and the lowest in females aged 31-40 years. Inter-group comparison of mean TCI revealed statistically non-significant differences in males and statistically highly significant differences in females (P<0.01).

Age estimation using TCI on mandibular first premolars can be recommended as an easy, non-invasive, and less time-consuming method. This study suggests that regression formulas were more accurate for males aged 31-40 years

Vitamin D deficiency appears to have a major effect on periodontal tissue health. The present study aimed to assess the association of the serum level of 25-hydroxyvitamin D and chronic periodontitis in postmenopausal women.

This research was done on 30 postmenopausal women with chronic periodontitis who all had at least 20 natural teeth. Intravenous blood samples were taken from the study population at baseline and after completion of non-surgical periodontal treatment. This was followed by assessment of serum levels of 25-hydroxyvitamin D. Next, clinical parameters of all teeth except for third molars were measured, which included pocket depth (PD), gingival index (GI), and plaque index (PI). Data were analyzed by paired t-test and its non-parametric equivalent, the Wilcoxon test. P<0.05 was considered significant.

The mean PD, PI and GI before and after the intervention were significantly different (P<0.05). There was, however, no significant difference between the mean vitamin D concentrations before and after treatment (P>0.05).

According to the results obtained in the present study, there is no association between serum vitamin D concentrations and chronic periodontitis in postmenopausal women.

This study aimed to assess the microtensile bond strength (µTBS) of etch-and-rinse (E&R), self-etch (SE), and universal adhesives to superficial and deep dentin.

In this in vitro study, 40 sound third molars were randomly divided into two main groups of superficial and deep dentin. Based on our classification, superficial dentin was right beneath the deepest occlusal groove, and deep dentin was 2mm beneath the deepest occlusal groove. Each group was divided into 4 subgroups (n=20) for application of Adper Single Bond 2 (ASB), Clearfil SE Bond (CSE), and Scotchbond Universal (SBU) in E&R and SE modes along with Charisma Smart composite resin on dentin. The specimens were incubated in distilled water at 37°C for 24 hours and their µTBS was then measured. The mode of failure was determined under a stereomicroscope at ×40 magnification. Data were analyzed by one-way ANOVA (alpha=0.05).

The highest µTBS belonged to the superficial dentin/SBU/E&R group. The µTBS was significantly higher in superficial dentin than deep dentin for all adhesives (P=0.005). There was no significant difference in mode of failure among the groups.

Based on the results obtained in the present study, type of bonding agent and application mode affected µTBS. In use of universal adhesive, E&R mode can improve µTBS.

The durability of composite restorations is directly affected by the mechanical properties of the composite. The aim of this study was to evaluate the hardness and wear resistance of self-adhesive flowable composite (SAF) in comparison with conventional flowable composites.

In this in vitro study, 50 composite specimens were prepared in brass molds with 10mm ×10mm ×2mm and divided into five groups (n=10). Specimens included three conventional flowable composites (Grandio flow, Filtek flow and Admira fusion flow), one self-adhering flowable composite (SAF, Vertise flow) and a microhybrid composite (filtek z250). After polishing, the micro-hardness of the specimens was measured in a Vickers hardness device, and the specimens were then subjected to 5000, 10000, 20000, 40000, 80000 and 120000 wear cycles in a wear tester. One-way ANOVA/Games-Howell, Kruskal Wallis, and Friedman tests were used for statistical analysis. The significance level was set at P<0.05.

The surface micro-hardness of the SAF was significantly lower than that of the microhybrid composite (P=0.01). There was no significant difference between the surface hardness of the different tested flowable composites (P>0.05). Also, the wear resistance of the studied composites was not significantly different in various cycles (P>0.05).

Based on our results, SAF would not be an ideal substitute for conventional flowable composites in high-stress areas.

Temporomandibular disorders (TMDs) include a series of signs and symptoms in the temporomandibular joints (TMJ) and muscles of mastication, which are associated with or caused by parafunctional habits. Many of these patients also suffer from lumbar pains. This study aimed to evaluate the effectiveness of treating parafunctional habits in alleviating symptoms of TMD and lower back pain.

This phase II clinical trial was conducted on 136 patients suffering from TMDs and lumbar pain, who consented to participate in this study. They were provided with instructions on how to discontinue their parafunctional habits including clenching and bruxism. The Helkimo and Rolland Morris questionnaires were used to assess TMD and lower back pain, respectively. Data were statistically analyzed using paired Student's t-test, Wilcoxon, Mann-Whitney, and Spearman correlation tests, with the significance level set at P<0.05.

The mean severity score of TMD significantly decreased after the intervention. Following treatment of TMD, the mean severity score of lumbar pain decreased from 8 to 2 (P=0.0001).

Based on our findings, it appears that the elimination of parafunctional habits improves TMD and lumbar pain.

Injuries to the maxillofacial region during contact sports is a well-known issue. Protective measures have been advised to prevent and reduce these problems. Awareness regarding the role of mouthguards in preventing temporomandibular joint (TMJ) injuries during contact sports, is limited. The aim of the present study was to assess awareness regarding the use of mouthguards during contact sports and incidence of TMJ injuries in sportspersons.

Eighty-six individuals training in contact sports were enrolled in the present study based on our inclusion and exclusion criteria. A questionnaire and clinical examination were used to assess TMJ pain, clicking, deviation, mouth opening, and locking.

The percentage of sportspersons aware of various protective gears was 23.8%. The awareness of TMJ injuries following contact sports was 6.9%, and 70.3% of the sportspersons were estimated to wear mouthguards. Clinical assessment of sportspersons using mouthguards revealed pain in 18.6% and clicking in 17.4% of the study subjects. The incidence of TMJ pain and clicking in individuals who did not use mouthguards were 81.4% and 82.6%, respectively.

Application of mouthguards can reduce the incidence of TMJ injuries in contact sports. They also contribute significantly to the overall dental health of the athletes, as well as improving their overall athletic performance and decreasing the likelihood of other types of oral and facial injuries.

This study aimed to assess the effect of different forms of fluoride application on surface roughness of rhodium-coated nickel-titanium (NiTi) orthodontic wires.

This randomized clinical trial was conducted on 15 patients randomly divided into three groups: toothbrush with Oral-B toothpaste only, Oral-B toothpaste, and daily mouthwash, Oral-B toothpaste, and sodium fluoride gel. The surface roughness indices of orthodontic wires including arithmetic mean height (Sa), root mean square height, root mean square gradient, developed interfacial area ratio (Sdr) and maximum surface height were measured by atomic force microscopy at baseline and after 6 weeks of application in the patients’ mouths. Data were analyzed by paired t-test, ANOVA, Games-Howell, and Tukey-HSD tests (P<0.05).

All surface roughness parameters in all three groups showed a significant increase after intervention, except for Sa in the toothpaste-only group (P=0.057) and Sdr in the sodium fluoride gel group (P=0.064).

The surface roughness of rhodium-coated NiTi orthodontic wires increases following the use of different forms of fluoride.

This study aimed to evaluate the pH changes and penetration of hydrogen peroxide into radicular dentin when different protective bases were used with and without a bonding agent.

In this in-vitro experimental study, 70 single-rooted bovine teeth were instrumented and obturated with gutta-percha. The gutta-percha was removed 3mm below the cementoenamel junction (CEJ) and the teeth were divided into seven groups (n=10). In each group, 2mm base (1mm apical to the CEJ) was applied as follows:  TheraCal LC, TheraCal LC plus SE Bond, Lime-Lite, Lime-Lite plus SE Bond, Ionoseal, Ionoseal plus SE Bond, and resin-modified glass ionomer (RMGI). The teeth were placed in vials containing distilled water, and pH values and molar concentration of the medium surrounding the teeth were recorded immediately after internal bleaching with 35% hydrogen peroxide. The pH values were also recorded at 1, 7, and 14 days following renewal of the medium. Data were analyzed with t-test, one-way ANOVA, and Kruskal-Wallis test. 

After bleaching, the medium pH became acidic in all groups. There were no significant differences among groups in the mean pH of the medium after bleaching (P=0.189). Moreover, there were no significant differences among the study groups with respect to hydrogen peroxide concentration (P=0.895).

Intra-orifice barriers such as light-cure resin-modified calcium hydroxide, light-cure resin-reinforced glass ionomer, and light-cure calcium silicate can be as effective as RMGI in providing coronal seal during intracoronal bleaching.

One of the most common methods used for the reconstruction of endodontically treated teeth is post and core and crown. Various factors such as the remaining tissue above the cutting margin (ferrule) affect the fracture resistance of teeth restored with post and core and crown. This study aimed to investigate the effect of ferrule/crown ratio (FCR) on the strength of maxillary anterior central teeth using finite element analysis.

A 3D scan of a central incisor was obtained, and the data were transferred to Mimics software. Then, a 3D model of the tooth was designed. Next, 300N load was applied at a 135° angle to the tooth model. Force was applied to the model both horizontally and vertically. Ferrule height was considered to be 5%, 10%, 15%, 20%, and 25% in the palatal surface and 50% in the buccal surface. The length of post in the model was 11, 13, and 15mm.

By increasing the FCR, stress and strain distribution increased in the dental model and decreased in the post itself. As the horizontal angle of load application increased, the level of stress and strain created in the dental model increased as well. The closer the force application site to the incisal area, the higher the stress and strain would be.

Maximum stress was inversely correlated with FCR and post length. In ratios of 20% and higher, insignificant changes occurred in stress and strain patterns in the dental model.

The current study aimed to assess the cyclic fatigue resistance of two nickel-titanium (NiTi) rotary files after immersion in 5% sodium hypochlorite (NaOCl) and Deconex.

In this in vitro study, 90 new M3 Pro Gold size 25.06 and size F2 SP1 files were tested. Forty-five files of the same brand were randomly distributed into three groups (n=15) and submitted to the following immersion protocol for 5 minutes at room temperature: no immersion (control group), immersion in 5% NaOCl, and immersion in Deconex. The cyclic fatigue resistance of the files was then measured in a custom-made tester. Two-way ANOVA was applied to compare the cyclic fatigue resistance of SP1 and M3 NiTi rotary files based on the type of disinfectant solution. Post-hoc LSD test was used for pairwise comparisons and P<0.05 was considered significant.

Two-way ANOVA indicated a significant difference in the mean cyclic fatigue resistance of M3 and SP1 NiTi rotary files. The M3 files immersed in NaOCL displayed the lowest and the SP1 files immersed in Deconex showed the maximum cyclic fatigue resistance. The effect of type of disinfectant solution (P<0.001) and type of NiTi file (P<0.001) on cyclic fatigue resistance was statistically significant.  

The cyclic fatigue resistance of NiTi rotary instruments can be affected by immersion in disinfectants, and the specific type of file and disinfectant used will ultimately determine the extent of this impact.

Nickel-titanium (NiTi) rotary files were introduced to optimize root canal instrumentation in endodontic treatment. However, despite the numerous advantages of NiTi instruments, they may unexpectedly break during clinical use, resulting in obstruction of the root canal system. This investigation aimed to assess the effect of cryotherapy on fracture resistance of Neoniti rotary files.

This in vitro, study was conducted on 20 Neoniti rotary files with #35 tip size and 6% taper in two groups with and without cryogenic treatment (N=10). For cryogenic treatment, the files were immersed in liquid nitrogen at -196°C for 24 hours. Next, the Neoniti files in both groups were subjected to cyclic fatigue testing in a hand-piece operating at 500 rpm with 20 N/cm torque. The files were rotated until fracture and the fracture time as well as the number of cycles to fracture were recorded for each file. The two groups were compared by independent t-test at 0.05 level of significance.

The number of cycles to fracture was 235700±50649.22 in the control and 280600±22979.21 in the cryotherapy group. The mean fracture time was 471.40±101.29 and 561.20±45.958 seconds in the control and cryotherapy groups, respectively. Significant differences in both variables were noted between the two groups (P<0.05).

Based on our findings, utilizing cryogenic treatment may enhance the fracture resistance of rotary instruments, making it a beneficial practice for dental clinicians to adopt. By using cryogenically treated rotary instruments, clinicians can potentially reduce the risk of file fracture during dental procedures.

Dental caries is a common chronic disease amongst children and are typically evaluated using the DMFT/deft index (decayed, missing, and filled teeth for permanent dentition/decayed, extracted, and filled teeth for primary dentition). To address the limitations associated with these indices, alternative assessment tools such as the Caries Assessment Spectrum and Treatment (CAST) index and Ora test have been developed. These methods aim to estimate caries activity within the oral cavity more accurately. The objective of our study was to evaluate and correlate caries activity in 5-to-8-year-old children using Ora test and CAST index.

Thirty schoolchildren between the ages of 5 and 8 years were selected and allocated into two groups (n=15) with DMFT/deft scores of <5 (group A) and >5 (group B). Two separate blinded examiners administered the assessments by first determining CAST scoring, which was followed by Ora test. Statistical analysis was performed using Pearson correlation test and significance was set at P≤0.05.

The mean time for color change of Ora test, was 118.53±23.28 minutes in group A and 53.33±15.07 minutes in group B. CAST severity scores were 3.67±2.08 and 15.7±9.70 for groups A and B, respectively. Time taken for color change in Ora test and CAST scores showed a significant negative linear relationship (P=0.039).

Based on the negative correlation between CAST scores and Ora test, it may be postulated that microbial activity is directly related to caries activity in 5-to-8-year-old children.

This study aimed to assess the efficacy of oral mucoadhesive N-acetylcysteine (NAC) tablets for treatment of recurrent aphthous stomatitis (RAS).

Forty-nine patients with RAS were randomized to receive mucoadhesive NAC tablets (n=25) or placebo (n=24). Tablets were prescribed three times a day for 7 days in each group. Pain intensity was evaluated with visual analog scale (VAS) three times a day from day 1 to day 7. Also, patients were clinically examined on days 0 (before entering the study), 3, 5, and 7 using a metal caliper to measure the diameter of the lesions. The data were statistically analyzed and P<0.05 was considered statistically significant.

Regarding the VAS score, all participants in the treatment group showed complete recovery on day 7 (P<0.01). Also, the diameter of the lesions was significantly smaller in the treatment group than the placebo group at the end of the study (P<0.001).

The results of this clinical trial showed for the first time that mucoadhesive NAC tablets can significantly decrease pain and the diameter of RAS lesions without any systemic complications.

Hardness is relevant to the degree of conversion (DC) and depth of cure (DoC). The aim of this study was to determine the micro-hardness and DoC of conventional and bulk-fill composite resins in class II restorations using metal and clear matrix bands.

Twelve specimens of each of the two composite resins, i.e., Filtek Z350 XT bulk-fill and Gradia posterior conventional composite, were prepared in the form of a class II cavity in a tooth mold, using a clear or metal matrix band. All specimens were cured and stored at 37°C for 24 hours. Vickers hardness was measured as a function of DoC at 2mm intervals. Data were analyzed by two-way ANOVA (alpha=0.05).

The bulk-fill composite exhibited significantly higher hardness levels than the conventional composite in all tested surfaces (P<0.001). However, while the metal matrix band had a significant impact on the bottom surface (P=0.059) and also on the furthest surface from the matrix and light source (P=0.04), it did not have a consistent effect across all tested surfaces. The simultaneous interaction of the composites and matrix band types in all surfaces, did not show significant differences in hardness values. The highest bottom-to-top surface hardness ratio (73%) was observed in the conventional composite near the metal matrix band.

In deep class II cavities, the bottom-to-top surface hardness ratio did not reach the maximum of 80%, neither for bulk-fill nor conventional posterior composites. Therefore, in such cavities extended light-curing and more incremental composite placement is needed.

Professionalism is essential to a strong trusted patient-doctor relationship, which is believed, could lead to more patient compliance and treatment outcomes. The purpose of our study was the development and psychometric analysis of an assessment tool for the professional behavior of dental students.

The study was done in the School of Dentistry, Tehran University of Medical Sciences. After providing a pool of various criteria to assess professionalism, an expert panel prepared the primary version of the tool. The tool was set in a questionnaire frame to explore the significance level and evaluation feasibility of each criterion. The questionnaire was completed by tutors of the “Medical Ethics” course (N=6). After necessary revisions, in order to evaluate face and content validity, the checklist was given to eight experienced dental educators to determine the relevance, clarity and simplicity of the questions. At the second stage, the final checklist with 37 items was given to dental educators to evaluate twenty students. To assess the reliability of this checklist, at least two professors evaluated each student and the weighted-  was calculated. Minor revisions were done according to feedbacks.

According to the obtained data, the total validity of the tool (S-CVI) was 100%. In all items, except just for one item, the weighted-  was greater than or equal to 0.5, showing sufficient reliability of these items.

The designed tool to evaluate the professionalism among dental students in different clinical departments seems to be both valid and reliable.

Registries are powerful tools for the collection and distribution of valid and reliable data. The initial step in health information management is to design a minimum data set that can improve the collection of high-quality data from the registry. The present pilot study aimed to determine the optimal minimum data set for dental implants to effectively utilize at Tehran University of Medical Sciences, Tehran, Iran.

This descriptive cross-sectional study was conducted in 2019 at Tehran University of Medical Sciences. A minimum data set checklist was developed based on our previous systematic review. The content validity of the minimum data set was approved by the recruited experts and the final minimum data set was established using the Delphi technique.

The minimum data set for dental implants consists of two separate sections - administrative and clinical data. The administrative portion includes two main segments: patient demographic data and clinic data, consisting of 12 data elements. The clinical part includes five main segments (patient clinical data, implant data, implant complications, implant loss, and implant follow-up), and contains 96 data elements.

This study suggests a minimum set of data for dental implants that can aid in efficient management of information, facilitate evidence-based decision-making, and enable high-quality clinical research, evaluation of treatment results, monitoring, and benchmarking of care.

To compare the effectiveness of fluoride varnish and two calcium-based fluoride products on the remineralization of primary teeth enamel.

Surface-microhardness (SMH) of 36 extracted anterior primary teeth was measured by Vickers test (50gr/5 seconds) to provide a baseline for later comparisons. All teeth were immersed in demineralizing solution for 96 hours to create caries-like lesions and SMH was determined for the artificially-induced caries. The teeth were randomly assigned to three groups consisting of 5% fluoride varnish once daily/10 seconds, Clinpro™ 5000 toothpaste once daily/2 minutes, and Remin Pro cream once daily/3 minutes for 28 days. All specimens were kept in artificial saliva with pH cycling during the study period. After remineralization, SMH was evaluated for the last time. Data were analyzed by one-way ANOVA, Mauchly's sphericity, and RM-ANOVA with Bonferroni correction for inter-and- intra-group comparisons at the three stages of the study.

Neither the baseline SMH nor the SMH of the artificially created caries showed significant differences among the samples (P>0.05). The post-treatment SMH was highest in the Clinpro group (296.4±73.1kgf/mm2), followed by Remin Pro (283.8±119.3kgf/mm2), and varnish (270.9±78.3 kgf/mm2). There was no significant difference among the groups after treatment (P>0.05). We also did not observe a significant difference among the three different study stages (P>0.05).

Within the limitations of this in-vitro study, daily application of low fluoride-calcium compound seems to be as effective as the professional use of fluoride varnish or high-content fluoride toothpaste in remineralizing initial caries of primary teeth.

Enlarged adenoids can lead to obstruction of the nasopharyngeal airway and subsequent oral respiration. Oral breathing can cause dry mouth, dehydration in gingival tissue, and resistance to plaque accumulation. This study aimed to evaluate the impact of tonsillectomy on oral health status, salivary pH and flow rate, and common complications caused by tonsillar hypertrophy in children.

An analytical before-and-after study was conducted on 60 children aged 5-12 years who required tonsillectomy. We gathered data through a questionnaire and collected unstimulated saliva using the spitting method for five minutes. Salivary pH was measured by a pH meter and its volume was determined with a calibrated test tube. The plaque index, bleeding index and modified gingival index were determined using a disclosing tablet, Williams’ probe and observational examination, respectively. All measurements were repeated one month after tonsillectomy. Paired t-test was used for data analysis.

We found a significant increase in mean pH and salivary flow rate after tonsillectomy and observed a decrease in oral health indices among the children one month after surgery. Over half of the children who reported complications such as dry mouth, itchy nose and throat, snoring, night sweats, and sleep disturbances experienced complete recovery after tonsillectomy.

Based on the results obtained in the present study, children with enlarged adenoids showed significant improvements in salivary pH, salivary flow rate, and oral health indices, one month after tonsillectomy.

This study aimed to investigate the impact of three different bleaching protocols on tooth discoloration caused by tea.

Forty extracted sound premolars were cleaned, disinfected, and their initial color parameters were measured (T1). The teeth were then immersed in boiled tea solution for 24 hours, and their color was measured again (T2). The samples were divided into four groups of 10 teeth each. Group A was treated with an in-office bleaching gel followed by 30 seconds of light curing. Groups B, C, and D were respectively treated with 0.24M oxalic acid followed by bleaching gel, 5.25% sodium hypochlorite followed by bleaching gel, and a combination of 0.24M oxalic acid, 5.25% sodium hypochlorite, and bleaching gel. The color was measured once more after the interventions (T3). Data were analyzed using two-way repeated measures ANOVA, paired sample t-test, and Tukey's test.

The mean color change (∆E2) between T2 and T3 was significantly higher in group D compared to group A (P<0.05). However, there was no significant difference in color change between groups A, B, and C. Additionally, there was no significant difference in color change between groups B, C, and D. The groups also showed significant differences in ∆L (P=0.007), with the only significant difference found between groups B and C (P=0.001).

The combined use of sodium hypochlorite and oxalic acid followed by in-office bleaching gel is more effective than bleaching alone in correcting tooth discoloration caused by tea. This protocol can further reduce yellow coloration.

Oral health literacy (OHL) is an interplay of cultural, social and individual factors and plays an effective role in public health promotion. This study aimed to assess OHL and its socioeconomic and demographic determinants among young couples.

This analytical cross-sectional study was conducted on 828 adults between 15 to 35 years in 2018 in Zanjan city. Data regarding their OHL were collected by using a 17-item Oral Health Literacy-Adult Questionnaire (OHL-AQ) that was filled out by a combination of self-report and interview. OHL was categorized as adequate, marginal, and inadequate. The effects of age and gender as demographic variables, and floor area per person as a proxy of financial status on OHL were also assessed. Data were analyzed using the linear and multinomial logistic regression models.

The mean OHL score was 7.86±3.83 out of 17 in equal number of males and females. Only 21% of the couples had adequate OHL. The socioeconomic, but not demographic variables had significant correlations with the qualitative and quantitative variables of OHL even after controlling for the effect of confounders. A correlation was particularly found between inadequate OHL and years of education [odds ratio:6.00; 95% CI: 3.86-9.28); P<0.001].

Socioeconomic factors had independent correlations with inadequate OHL. Participants with higher levels of education, those living in urban areas, and individuals with better financial status had higher levels of OHL and lower odds of inadequate OHL.

The aim of this study was to assess how different soft drinks affect the deterioration of conventional and memory orthodontic elastomeric chains.

We used 500 five-loop segments of elastomeric chains, which were divided into two equal groups of conventional and memory chains. The samples were kept in artificial saliva during the study period. Each group was further divided into 5 subgroups consisting of artificial saliva (controls), Coca-Cola®, non-alcoholic beer (ISTAK®), and carbonated and non-carbonated yoghurt-based drinks (Alis®). Treatment with the soft drinks consisted of immersion in the test liquids twice a day for 3 minutes each time. Force measurements were taken on days 1, 7, 14, 21, and 28. Data were analyzed using One- and three-way ANOVA tests, and independent t-test, with a significance level of 5%.

The mean initial force for the conventional and memory elastomeric chains was 3.34±0.112N and 2.49±0.209N, respectively. Conventional chains showed significantly greater degradation than memory chains (P<0.01). Soft drinks had a significant impact on force degradation for both types of chains at all time points (P<0.01). Coca-Cola® had the highest level of force degradation, while non-carbonated yoghurt-based drinks had the lowest (P<0.01).

Based on the findings of this study, it is recommended that orthodontic patients choose non-carbonated yoghurt-based drinks during their treatment. Memory elastomeric chains may be more suitable for patients who consume large amounts of carbonated soft drinks, due to their lower amount of force degradation compared to conventional chains.

Due to their aesthetic appeal and translucent properties, clear thermoplastic retainers have become increasingly popular. However, ensuring their proper maintenance and cleaning is a significant challenge. It is essential to prevent any negative impact of cleaning solutions on the translucency and color consistency of retainers. Therefore, this study aimed to assess the effect of different cleaning solutions on the light transmission (translucency) rate of two distinct types of clear thermoplastic sheets.

Two different clear thermoplastic sheets (Erkodent, Shodental), and five disinfectant solutions including chlorhexidine, Listerine, hydrogen peroxide, GUM whitening, and acid acetic served as the study materials and distilled water was used as control. The samples in each group (N=12) were immersed in the respective solutions for 15 minutes, twice a week and their light transmittance was measured using spectrophotometry after one and three months. Statistical analysis was conducted using two-way analysis of variance, with the significance level set at P<0.05.

Light transmittance decreased from baseline to 3 months for all study groups. After three months, the lowest translucency was related to retainers manufactured with Erkodent sheets, cleaned with GUM whitening (74.11±10.72%). The highest translucency after this period was found in retainers prepared with Shodental sheets immersed in Listerine mouthwash (88±1.55%). Only retainers treated with hydrogen peroxide showed significant difference between the thermoplastic sheets, which was higher in Erkodent (P<0.05).

Our findings indicated that among the studied solutions, cleaning translucent retainers with Listerine mouthwash twice a week has the least effect on light transmission.

This in-vitro study aimed to evaluate the physical properties of three resin-based root canal sealers, including BETA-RCS, AH26, and Adseal.

Flowability, film-thickness, solubility, and radiopacity of BETA-RCS, AH26, and Adseal sealers were evaluated according to ISO 6876/2012 specifications. Three samples of each sealer were used to test each of the properties.

The results revealed that the flow rate (mm) of BETA-RCS, Adseal, and AH26 were 23.06±1.58, 22.5±4.23, and 21.85±1.71, respectively. Film-thickness values (µm) for BETA-RCS, Adseal, and AH26 sealers were 52.33±2.51, 18.66±0.57, and 52±2, respectively. No significant difference was observed regarding filmthickness between AH26 and BETA-RCS (P>0.05), while Adseal showed significantly lower film-thickness (P˂0.05). The highest and lowest solubility were related to BETA-RCS and Adseal, respectively. However, all sealers had acceptable solubility and radiopacity.

The findings of the current study suggested that all three root canal sealers including BETA-RCS, AH26, and Adseal had similar properties based on ISO 6876 standard criteria. As such, they could be viable choices for facilitating effective root canal procedures. Further long-term clinical studies are warranted to assess their performance and success rates in actual endodontic cases.

The adenomatoid odontogenic tumor (AOT) is a rare benign neoplasm that is typically treated through surgical enucleation and curettage. Any impacted tooth associated with the tumor are also extracted during the procedure. We present a case of AOT encompassing an impacted left maxillary central incisor in a 13-year-old male. The patient underwent routine treatment, but the tooth was orthodontically extruded using traction. Within two years, the incisor successfully attained its functional position in the arch, without any signs of recurrence. Preserving an impacted tooth associated with AOT is not common, and only a few cases have been reported in the literature. It is important to manage AOT conservatively and to save the associated tooth for both functional and aesthetic purposes. Long-term follow-up is crucial to monitor any potential recurrence. In summary, our case highlights the successful orthodontic management and preservation of an impacted tooth in a teenager with AOT.

 The aim of this in vitro study was to assess the quantity of nickel and chromium ions released from orthodontic wires when subjected to various beverage solutions and distilled water.

 Orthodontic appliances composed of five brackets, one band and 0.016-inch stainless steel and nickel titanium wires were immersed in Coke, tea, coffee and distilled water. The samples were incubated at 37℃ for 1 hour, 6 hours, 24 hours, and one week. There was a total of 120 appliances divided into 24 groups (n=5 in each group). Atomic absorption spectroscopy was used to examine the amount of released ions. Two-way and one-way ANOVA followed by Tukey test were used for statistical analysis and P<0.05 was considered significant.

 The release of nickel ions from both wires was highest in Coke and lowest in distilled water at all time points. Coffee and tea demonstrated values in-between these two limits. Similarly, chromium ion release from both wires was highest in Coke at all time-points compared to all other solutions (P<0.05). None of the other tested drinks showed significant differences in chromium ion release compared to distilled water.

 Restricting the intake of acidic drinks, particularly carbonated beverages like Coke, plays a critical role in safeguarding orthodontic wire components. Educating patients and providing dietary guidelines are essential for maximizing treatment effectiveness. Further research is required to investigate additional factors impacting ion release and devising methods to mitigate potential harm.

 Dental anxiety is a common phenomenon experienced by children in the dental setting. However, there is limited research on the effectiveness of cognitive-behavioral interventions in managing this anxiety. Therefore, the aim of this study was to evaluate the impact of a cognitive-behavioral psychologic intervention on dental anxiety in children.

 A total of thirty children, aged 7-10 years, underwent prophylaxis and fluoride therapy. The baseline anxiety levels of the children were determined using the Modified Child Dental Anxiety Scale (MCDAS). The intervention group (N=15) received two 30-minute sessions of cognitive-behavioral exercises. Additionally, a short film demonstrating a cooperative child undergoing pulpotomy was created and parents were instructed to show it to their children at home. During the treatment session, the exercises were reinforced at each step, and the MCDAS questionnaire was administered again. The children’s behavior was also assessed using the Venham Clinical Cooperation Scale. Independent t-test, Mann-Whitney, chi-square, and Pearson’s correlation coefficient were used for statistical analysis and P<0.05 was considered statistically significant.

 Postoperatively, the MCDAS score in the intervention group was significantly lower compared to the control group. Notably, the intervention group demonstrated a downward trend in anxiety scores, while the control group showed an increase (P<0.001).

 Cognitive-behavioral interventions were found to be successful in decreasing dental anxiety in children undergoing pulpotomy. These interventions can be successfully implemented in clinical settings.

This study aimed to investigate the effect of common mouthwashes on the color change of a nanohybrid composite and its further stain susceptibility to Coke and coffee.

One hundred and fifty composite discs were prepared and initial color values were measured using a spectrophotometer. The specimens were grouped based on the 24h exposure to common mouthwashes including Listerine, chlorhexidine, two types of fluoride mouthwashes (alcohol free and alcohol containing) as well as distilled water as control (N=30). The color change (ΔE1) values were calculated to show the amount of color change caused by mouthwashes. Subsequently, the specimens in each group were subdivided and immersed in the secondary colorant solution (coffee, Coke and, distilled water) for seven days. The total color change (ΔE total) values were obtained to show the stain susceptibility. Statistical analysis was conducted using ANOVA and Tukey’s post hoc test. A P-value less than 0.05 was considered statistically significant.

The calculated ΔE1 of resin composite was significantly higher for all mouthwash groups than that of the control group; however, all were in the clinically acceptable range. Exposure to Listerine and distilled water caused more staining effects compared to other mouthwashes after immersion in secondary colorant solutions. Regardless of primary mouthwash type, coffee and distilled water caused the highest and the least total discolorations, respectively (P<0.001).

All mouthwashes caused a clinically acceptable color change in resin composite; however, further stain susceptibility depended on the mouthwashes but was not higher than distilled water

This report details the successful prosthetic rehabilitation of a 25-year-old male patient with Papillon Lefèvre Syndrome (PLS) using an implant-supported hybrid prosthesis. Six implants were placed in the maxilla, and four were placed in the mandibular arch. All implants were inserted axially (non-tilted) and were planned to be loaded after a healing period of 6 months. One implant failed due to graft loss during the healing phase, which was removed and the remaining implants were restored with a hybrid prosthesis after 6 months, using the delayed loading protocol. The patient was followed-up for four years and all the remaining implants successfully integrated and remained fully functional during this period. The prosthesis significantly improved the functional, aesthetic, and psychological well-being of the patient. This case report is the first of its kind to use only four axially placed implants for rehabilitation of a PLS patient with a successful four-year follow-up.

Oral schwannomas (OSs) are uncommon benign nerve sheath tumors accounting for 1% of all schwannomas and may arise from either soft tissue or bone. Cellular schwannoma is a rare histological variant of schwannoma which is characterized by increased cellularity. The most common intraoral site of occurrence is the tongue followed by the floor of the mouth and palate. Here, we are reporting a rare case of intraoral cellular schwannoma involving both facial and palatal gingiva of the right maxilla in a young Indian male patient.

 This in vitro study aimed to compare the effect of external staining agents (black tea and grape juice) on the color change of three hybrid ceramics including a new material in comparison to zirconia-reinforced lithium silicate.

 Ten samples of two hybrid dental ceramics including Vita Enamic (Vita Zahnfabrik) and Crystal Ultra (Digital Dental) in addition to a resin nanoceramic, Lava Ultimate (3M ESPE); and a zirconia-reinforced lithium silicate glass ceramic, Vita Suprinity (Vita Zahnfabrik) were prepared and immersed in black tea or grape juice for 30 days. A spectrophotometer was used to evaluate color change. All samples were carefully chosen in A3 shades or their equivalent. Two-way ANOVA and Bonferroni tests were used to analyze the color differences (ΔE00) among the materials and the staining solutions at a significant level of 0.05.

 Significant color changes were observed in Vita Enamic and Lava Ultimate groups after immersion in both solutions (P<0.001). The least color changes (ΔE00) belonged to the Vita Suprinity (1.34) and Crystal Ultra (1.92) groups, respectively.

 The color changes of Vita Enamic and Lava Ultimate materials were beyond clinical acceptability. However, the mean color changes of Vita Suprinity and Crystal Ultra groups were clinically acceptable.

 The objective of this study was to investigate the impact of an educational intervention, guided by the Health Belief Model (HBM), on promoting preventive behaviors among mothers to combat early childhood caries (ECC) in toddlers aged 12 to 18 months.

 This single-blind interventional study evaluated 92 toddlers between 12 to 18 months and their mothers, who were selected by stratified random sampling. Data regarding demographic and nutritional factors were collected using a questionnaire. The dental status of children was evaluated by clinical examination and measuring the plaque index (PI) of maxillary central incisors and the dmfs index. A pamphlet designed according to the HBM was used for oral hygiene instruction in both the intervention and control groups. All of the mothers in the intervention group received a music file to listen to when brushing their children’s teeth. Data were analyzed using chi-square, Fisher exact, Mann-Whitney, and Wilcoxson tests. P<0.05 was considered significant.

 No significant correlation was noted between the daily frequency of sugary substance intake and primary PI in the intervention or control group with/without dental plaque (P>0.05). In the intervention group, PI significantly decreased after the intervention compared to baseline (P<0.001). However, there was no significant change in PI after the intervention in the control group compared with baseline (P=0.1).

 The findings indicate that a combination of educational intervention and incentives, such as using age-appropriate music for toddlers, can significantly enhance mothers' effectiveness in removing dental plaque.

There is limited knowledge on the efficacy of universal adhesives when used in different etching modes. The aim of this study was to evaluate the microtensile bond strength (µTBS) to dentin using universal adhesives with light-cure and dual-cure composites.

In this in vitro experimental study, the occlusal third of 60 caries-free human molars were removed and the exposed surfaces were treated and allocated to 10 groups (N=6). Two different bonding agents (Single Bond Universal, G-Premio) were used to bond 2 different composite resins (Z250 light-cure and CoreFlo DC dual-cure) to dentin, using etch-and-rinse (E&R) and self-etch (SE) modes. Single Bond 2 was applied in E&R mode on wet dentin to serve as control. The specimens were sectioned into 1×1 mm2 sticks with a precision saw. A microtensile testing machine was used to measure the µTBS of the specimens with a crosshead speed of 0.5 mm/min. Data were analyzed using three-way ANOVA and Bonferroni post-hoc test (α=0.05).

The Single Bond Universal group in SE mode with light-cure composite yielded the highest (39.24MPa), and the G-Premio SE group with dual-cure composite produced the lowest (13.65MPa) mean µTBS (P<0.05). The dominant failure mode was adhesive, in all groups.

The bonding agent had a significant effect on µTBS of composite to dentin, but different composites and different etching modes were not significantly different in this respect.

 This study aimed to assess the effect of extent of white spot lesions (WSLs) on the esthetic outcome (masking effect and durability) for 6 months after treatment by the resin infiltration technique.

 In this clinical trial, 79 teeth with WSLs in 18 patients were selected. The lesions were assigned to localized and generalized groups, and were all treated by resin infiltration. The color of WSLs was assessed at baseline, immediately after treatment, and 1, 3, and 6 months after treatment by using Easy Shade spectrophotometer and taking standard digital photographs. The surface area of WSLs was calculated on the photographs using MIP4Student software. Repeated Measures ANOVA was used to compare color change (∆E), and the Pearson’s correlation test was applied to analyze the association between the extent of lesions and ∆E (alpha=0.05).

 A significant difference was found between the two groups in ∆E at different time points (P<0.05). Also, in both localized and generalized lesions, the pretreatment ∆E was significantly different from the ∆E values at different time points after treatment (P<0.001). However, the post-treatment ∆E values were not significantly different (P>0.05). The Pearson test showed an inverse correlation between the extent of lesions and ∆E (P<0.05).

 The resin infiltration technique is successful in masking the WSLs, with a durability of at least 6 months. Color correction by this technique is more favorable in localized lesions.

 The aim of this study was to investigate barriers to the accessibility of emergency pediatric dental care services during the coronavirus disease 2019 (COVID-19) pandemic from the viewpoint of parents in Mashhad, Iran.

 A qualitative study was conducted on a purposive sample of parents seeking emergency dental care for their children during the COVID-19 pandemic. Data were collected through semi-structured face-to-face interviews. The participants were asked, “Were there any barriers encountered when seeking emergency dental care for your child during the COVID-19 pandemic?”. If any barrier was faced, the parents were asked to explain about it. All interviews were recorded and transcribed verbatim. The thematic content analysis of the transcripts began after the first interview, and the interviews and analysis process continued until data saturation was achieved.

 In total, 26 parents were interviewed. The thematic content analysis of the transcripts led to the recognition of three main categories of barriers: “fear of COVID-19”, “financial constraints”, and “dentists’ less occupational activity”. “fear of COVID-19” had two subcategories: “fear of contracting COVID-19” and “fear of transmitting COVID-19 to others”. “financial constraints” also had two subcategories: “increased costs” and “decreased income”.

 From the viewpoint of parents seeking emergency dental care for their children in Mashhad, Iran, there were various barriers to the accessibility of emergency pediatric dental care services during the COVID-19 pandemic. The barriers were not limited to the fear of COVID-19 and were partly outside the control of dentists and parents.

This study aimed to assess the impact of recommended mouthwashes (chlorhexidine, hydrogen peroxide, and povidone-iodine) used during the COVID-19 pandemic on the shear bond strength (SBS) of orthodontic brackets.

A total of 52 human premolar teeth were divided into 4 groups (N=13) consisting of no intervention (control group), 0.2% chlorhexidine, 1.5% hydrogen peroxide, and 0.2% povidone-iodine. Following immersion in the mouthwashes, orthodontic brackets were bonded to enamel surfaces. Then, the brackets were debonded using a universal testing machine. The specimens were evaluated with a scanning electron microscope (SEM) and adhesive remnant index (ARI) score was assessed. One-way ANOVA and Tukey test were used for statistical analysis and P<0.05 was considered significant.

The SBS of the experimental groups decreased compared to the control group. The highest SBS mean value was observed in the controls and the lowest was found in the 0.2% povidone-iodine group. Significant differences in SBS values were found between the 0.2% povidone-iodine group and the 1.5% hydrogen peroxide group when compared to the control group (P=0.023, P=0.028, respectively). SEM analysis revealed similar characteristics among the groups, with a closer resemblance between the chlorhexidine and control groups. Additionally, these groups exhibited greater etching depth compared to the other groups.

Our findings highlight the importance of careful selection and application of mouthwashes in orthodontic procedures. While 1.5% hydrogen peroxide and 0.2% povidone-iodine may have some impact on bond strength, their use can still be considered acceptable within defined limits.

The purpose of this study was to compare the effect of plasma irradiation and other surface preparation methods on the microtensile bond strength of repaired resin composites.

Twenty molds of a universal nanohybrid composite were prepared, aged and subjected to thermocycling. The specimens were divided into 5 groups for surface preparations including, C (Control): application of GC G-Premio Bond (GP) only; SB: sandblasting with alumina and GP; SI: application of phosphoric acid etching, silane, and unfilled resin; RB: roughening by diamond bur, phosphoric acid etching and GP; PL: application of argon and atmosphere plasma and then GP. The specimens were repaired with the new resin composite, cut to 1mm2 beam, and then subjected to thermocycling. The microtensile bond strengths were measured using a universal testing machine. The failure modes were assessed with a stereomicroscope. Data were analyzed using two-way ANOVA and Tukey's test. The level of significance was α=0.05.

The highest mean bond strength was found for the application of universal bonding GC GP in controls (26.62MPa) and the lowest average bond strength belonged to the SI groups (9.06MPa). The difference in the mean bond strength between the SI group and other groups was significant (P<0.05). The failure mode of specimens in all groups was predominantly adhesive.

The application of GP as an intermediate universal adhesive established a proper bond between the old and new resin composite. In addition, the plasma application and other surface preparation methods did not significantly improve the bond strength.

This study aimed to evaluate the shear bond strength (SBS) of two repair composites (Crea.lign vs. PermaFlo) to a base metal alloy and zirconia ceramic.

Sixty-four discs (12mm diameter, 1mm thickness) were fabricated using Wirobond base metal alloy and zirconia. They were then bonded with their respective composite resins (N=16) in each of the two porcelain chipping repair kit subgroups consisting of PermaFlo and Crea.lign. All specimens were stored in 37°C distilled water for 24 hours. Half of them were subjected to 10,000 thermal cycles (5-55°C, 30s). All specimens were tested for SBS with a universal testing machine. Failure types were analyzed using a digital camera. Analysis of the data was done by two-way ANOVA and Bonferroni post-hoc tests.

SBS was significantly affected by the type of composite resin. PermaFlo had a significantly higher SBS than Crea.lign to base metal alloy (P<0.001) and zirconia ceramic (P<0.001). Thermocycling decreased the SBS of both composites to base metal alloy (P<0.001) and zirconia (P<0.001).

A universal adhesive could provide higher shear bond strength of zirconia and base metal alloy to composite resin than Crea.lign composite and the MKZ primer supplied by its manufacturer.