Dental Research Journal
Volume:20 Issue: 2, Feb 2023

During the orthodontic bonding process, the need for repositioning or rebonding of orthodontic brackets on the enamel surface occurs frequently. The aim of this study is to compare the shear bond strength (SBS) in rebonding orthodontic stainless steel brackets with three different methods of enamel surface conditioning methods.

In this in vitro study, 80 human premolars that were extracted for orthodontic purposes were randomly divided into four groups and underwent orthodontic bonding procedure (N = 20). Except for the control group, three other groups underwent debonding and rebonding process in which after removing the remaining adhesive with tungsten‑carbide bur, enamel surface conditioned by three different methods including re‑etching with phosphoric acid, sandblasting + acid etching, and Erbium‑doped Yttrium–Aluminum–Garnet laser. Then, the SBS of the bracket to the enamel surface was compared between different groups. Scanning Electron microscopy images were also obtained from a number of samples. Statistical analysis was performed by Kruskal–Wallis and Mann–Whitney tests.

The highest SBS was observed in the primary bond (control group) with an average of 29,440 MPa. There was a significant difference between the studied groups (P < 0.001) and only the group that was re‑etched with phosphoric acid had no significant difference with the control group (P = 0.708) ∝ =0.05.

Rebonding of brackets using phosphoric acid for reconditioning of the enamel surface creates bond strength comparable to the primary bond. Other groups had significantly lower SBS than the control group

Dentistry practice has become more complex and challenging in the recent years. The clinical decision‑making process has experienced many problems due to changing socioeconomic patterns, knowledgeable patients, rapid technological advances, and information explosion. The present study reviewed the status of the attitude toward evidence‑based dentistry (EBD) among dental students of Iran Universities. The effect of the educational intervention was also assessed.

This systematic review was conducted according to the Preferred Reporting Items for Systematic review and Meta‑Analysis checklist. Search strategy was developed by Medical Subject Headings terms and keywords surfing electronic available databases including Medline/PubMed and Google Scholar and local databases such as Scientific Information Database (SID) and Magiran. Two reviewers read the abstracts of all eligible papers and excluded the duplicates. They extracted the information of the full‑text of the studies included in the review and assessed the quality by Joanna Briggs Institute critical appraisal checklist.

Ten studies including 8 cross‑sectional and 2 interventional studies met the criteria. The assessment of the attitude of 937 dental students from a different region of the country toward EBD showed moderate to acceptable status using 3 different tools. In regard to educational interventions, 2 studies were successful to improve their attitude.

Although the researchers presented good scores on the attitude questionnaires, the quality of the study tools, the eligible criteria for recruiting the participants and the method of evaluating the construct of attitude should be investigated in future studies.

Bonded composites may increase bacterial accumulation and caries formation risk. Therefore, assessment of methods to decrease bacterial activity around them would be valuable. The literature on the efficacy of adding silver nanoparticles to fiber‑reinforced composite (FRC) or adding them to bonding agents in terms of their antibacterial activity and/or shear bond strength (SBS) is scarce. Thus, we aimed to assess the antibacterial activity of flowable composites and bonding agents containing various percentages of experimental silver nanoparticles(nanosilver) against S. mutans and to evaluate the SBS of FRC and bonding agents containing different amounts of nanosilver to enamel.

In this preliminary study, 0% (control), 0.5%, 1%, 2.5%, and 5% nanosilver were added to flowable composite and bonding agent. Syntheses of nanosilver and nanosilver‑incorporated composite specimens were approved using X‑ray diffraction spectroscopy and scanning electron microscopy. Antibacterial effects of the produced materials on S. mutans were evaluated by colony count with serial dilution method (n = 7 groups × 10 [n = 70] specimens) and agar disc diffusion test (n = 6 groups × 5 [n = 30] composite specimens + n = 6 groups × 5 [n = 30] light‑cured bonding + n = 6 groups × 5 [n = 30] uncured bonding) against negative control and cefotaxime antibiotic. Moreover, SBS values of various FRC blocks bonded to enamel using various bonding agents were measured (n = 9 groups × 6 [n = 54] human premolars). Data were analyzed using Kruskal–Wallis, Dunn, two‑way analysis of variance, and Tukey’s tests (α = 0.05).

Composite discs containing all concentrations of nanosilver reduced S. mutans colony counts (P < 0.05); bacterial growth was ceased at samples containing 2.5% and 5% of nanosilver. The reduction in the SBS of FRCs was significant only for 5% nanosilver (P < 0.05).

Adding 0.5%, 1%, and 2.5% nanosilver to composite and 0.5% or 1% nanosilver to bonding agent led to a significant antibacterial behavior against S. mutans while not significantly affecting the SBS of FRC.

Pain following surgical removal of impacted molars has remained a principal concern among practitioners. Since green tea has anti‑inflammatory and anti‑bacterial properties, the current study aimed to evaluate the efficacy of green tea extract local application in controlling postoperative pain following surgical extraction of the impacted mandibular third molar teeth.

In a double‑blinded randomized controlled trial study with a split‑mouth design, 32 patients underwent bilateral removal of impacted third molars in a 2‑month time interval; afterward, the sterile gauzes impregnated with green tea extract and saline were applied randomly to the surgical sites. Postoperative pain was evaluated 6, 12, 24, and 48 h after surgery using a questionnaire based on the Visual Analog Scale (VAS) and the number of analgesics used after surgery. Data were subjected to exact and Chi‑square tests with the significance level set at 0.05.

There was a decrease in the mean scores of the VAS and the mean number of analgesic consumptions in the first 2 days after surgery. Chi‑square test results showed a significant reduction in the VAS scores after applying the green tea extract only 6 and 12 h after surgery (P < 0.05). Moreover, the number of analgesic consumptions was significantly lower in the green tea group compared to the control group.

Green tea extract may be an appropriate and safe choice for postoperative pain control after surgical extraction of the impacted mandibular third molar teeth.

Minimally invasive techniques should be employed to maintain pulp vitality without affecting physiological tooth resorption for pediatric patients. This study aims to evaluate clinical and radiographic success of light cure calcium silicate and resin‑modified glass ionomer (RMGI) as indirect pulp‑capping agent in primary molars in children between 5 and 9 years.

In this randomized clinical trial study, 40 primary molars with the International Caries Detection and Assessment System criteria 4–6 score were divided randomly into two groups after computerized randomization method. After caries excavation by minimally invasive dentistry principle, affected dentin was lined by either light cure calcium silicate (Group I) or RMGI (Group II) liner followed by composite restoration. Clinical success was determined with the absence of symptoms and bitewing radiographs were taken at baseline, 3, and 6 months’ interval to measure increase in dentin increment using ImageJ software. Statistical analysis for intergroup comparison was done using Paired t‑test, and Independent t‑test was used for intragroup comparison. The level of statistical significance was set at P < 0.05.

Change in dentin increment seen from baseline to 6 months in Group I was 0.19 mm and in Group II was 0.20 mm (P = 0.924). Intragroup increment was statistically significant during all follow‑up intervals for both the groups (Group I – P ≤ 0.001, Group II – P = 0.009). For baseline remaining dentin thickness >1.5 mm, statistically significant increase was observed in the dentin increment at 3 months’ interval between both the groups.

Both TheraCal LC and Vitrebond show acceptable clinical and radiographic results when used in primary molars as indirect pulp treatment agents. Both the liners are equivalent to each other in terms of feasibility and cost‑effectiveness but TheraCal LC can be preferred due to better handling and avoiding the manipulation step thereby reducing treatment time.

The present study was conducted to develop a standard questionnaire to assess the knowledge and practice of prosthodontists regarding the diagnosis and treatment of obstructive sleep apnea syndrome (OSA).

This study had questionnaire designing and cross‑sectional‑descriptive phases. Questionnaire domains were identified by a panel of eight experts. The face and content validity of the questionnaire was assessed by experts and four laypeople. The internal consistency reliability of the questionnaire was checked using Cronbach’s alpha coefficient. Moreover, its stability was tested using the test–retest method. The questionnaire was completed online by 282 Iranian prosthodontists and the relationship between different variables and scores of knowledge and practice of them with simple and multiple linear regression tests was were analyzed.

A 32‑item questionnaire was designed. The Scale Content Validity Index was >0.8 for clarity, simplicity, and necessity in all domains and the content validity of all questions was above 0.8. As for reliability, Cronbach’s alpha coefficient was above 0.7 on average. Faculty members had more knowledge (P = 0.04) and better practice (P = 0.001) compared to others. Prosthodontists who participated in sleep disorders training courses had higher scores in knowledge (P = 0.001) and practice (P = 0.001). Prosthodontists who referred patients to sleep disorders clinics had higher knowledge (P = 0.001) and practice (P = 0.001) than those who did not.

The questionnaire developed in this study can be considered a comprehensive and executable scale with appropriate reliability and validity. There is a positive relationship between being exposed to information and the level of knowledge and practice of prosthodontists about OSA.

The demand for an ideal root canal filling material in primary teeth with maximum antibacterial properties keeps escalating to improve the success rate of root canal treatment in primary teeth. Hence, the present study was conducted to determine the antimicrobial efficacy of the different concentrations of a novel root canal filling material.

An in vitro study was designed to compare the antimicrobial efficacy of different concentrations of the novel obturating material for primary teeth. Different concentrations of the novel obturating material were prepared using calcium hydroxide, zinc oxide cement, and metronidazole and were tested for its antimicrobial efficacy against Streptococcus mutans and Enterococcus faecalis using Mueller–Hinton Agar for 24 h at 37°C. The zone of inhibition was measured in millimeters after 24 h. The values were entered into a Microsoft Excel spreadsheet and subjected to statistical analysis. Descriptive statistics were used for data summarization and presentation. Friedman test and Kruskal–Wallis test were used to compare the different concentrations of the novel obturating materials against S.mutans and E.faecalis. P < 0.05 was considered to be significant.

Against S. mutans at 1% concentration, the zone of inhibition was statistically greater at 50 μl and at 2% and 3%, the zone of inhibition was greater at 100 μl. Similarly, against E. faecalis, the zone of inhibition was statistically greater at 100 μl at 2% and no significant difference was noted at 1% and 3%. Comparison between the groups at 25, 50, and 100 μl shows no significant difference against S. mutans between 1%, 2%, and 3% of 60–40 concentration. However, 3% 60–40 concentration at 50 μl shows significantly increased zone of inhibition against E. faecalis.

Two percentage metronidazole at 60–40 (calcium hydroxide–zinc oxide) concentration of the novel obturating material at 100 μl has better antibacterial properties against both S.mutans and E. faecalis.

The use of a rubber dam is more important than ever in today’s COVID‑19 era to limit cross infections. In children, the placement of the metal clamp to retain the rubber dam is perceived to be painful and often requiring a local anesthetic injection. This dissuades many clinicians from placing the rubber dam. Hence, this study evaluated the pain response of children to a SoftClamp™ compared to the conventional metal clamp.

This was a randomized controlled, equal allocation ratio, split‑mouth clinical trial. Forty‑two children aged between 8 and 12 years, having two permanent mandibular molars in need of sealants, were divided into Groups A and B (metal clamp and SoftClamp™, respectively). The pain response was recorded using both an objective and a subjective scale i.e.,the Faces Legs Activity Cry Consolability (FLACC) scale and the Wong Baker Faces Pain Rating Scale (WBFPRS).The level of significance was set at 5% (P < 0.05).The pain response recorded from the WBFPRS and the FLACC scale for the metal and the SoftClamp™ were analyzed using the Wilcoxon signed rank test. The difference in pain response between genders and between two age groups (below and above 10 years of age) was analyzed using the Mann–Whitney U‑test.

The children reported mild discomfort to clamp placement in both the scales. The P values for the FLACC and WBFPRS scores comparing the pain response to the metal and SoftClamp™ were 0.311 and 0.149, respectively.

There was no significant difference in the pain response of children to both the clamps.Good rubber dam application practices in children through the use of behavior guidance and a proper topical anesthesia technique may play a far more important role regardless of the clamp used. But the SoftClamp™, with its more child friendly appearance could be a viable alternative to the metal clamp in children.

The temporary cement remaining inside the dental prosthesis can act as a source of microbial colonization and contamination and decrease the final cement retention. Consequently, complete removal of temporary cement before permanent cementation is suggested. This study aimed to assess the effect of different cleaning methods for removing temporary cement on the tensile bond force (TBF) of permanently cemented implant‑supported zirconia copings.

In this in vitro study fifty titanium abutments were screwed onto 50 analogs with 30 Ncm torque into in acrylic resin blocks. Each abutment was scanned separately, and 50 zirconia copings were designed and milled. Permanent resin cement was used to cement copings of control group (N = 10). Copings were divided into two temporary cementation types that in each group, two cleansing methods were used: Temp‑S (temporary cement with eugenol and sandblasted after debonding), Samples of the control group were placed in the universal testing machine, and the TBF values were recorded. Samples of the test groups after debonding and cleaning the abutments were subjected to cement with permanent resin cement, aging, and removing. Levene test, two-way analysis of variance (ANOVA), and Tamhane post hoc tests were applied. α = 0.05.

The highest and lowest TBF values were found for the TempNE‑SU (554.7 ± 31.5 N) and Temp‑S (492.2 ± 48 N) groups, respectively. The two groups of isopropyl alcohol baths in ultrasonics in combination with sandblasting showed statistically higher TBF values than the other two groups that used only sandblasting (P < 0.001) and had similar values compared to the control group.

Sandblasting combined with immersion in an ultrasonic bath containing isopropyl alcohol resulted in statistically similar values to the values of cementation with resin cement from the beginning. However, cleaning the inside of the copings only by sandblasting method reduced the values of the final retention force in comparison to cement with permanent resin cement from the beginning.

The aim of this study was to compare the clinical, histological, and histomorphometrical outcomes of CenoBone® allograft with and without plasma rich in growth factor (PRGF) for the preservation of edentulous ridge in the dental sockets.

This study is experimental clinical trial that 14 dental sockets were included the sockets required ridge preservation followed by implant placement in the premolar and molar of the mandible. After extraction of the teeth, the CenoBone® allograft and PRGF were used in the test group and CenoBone® allograft was used alone in the control group. During the first stage of surgery and 5 months later, in the second stage of surgery (implant placement), the vertical changes of the ridge were measured. Furthermore, using Core‑Biopsy in the second stage of surgery, criteria of histologic and histomorphometric were determined. Data were analyzed with t‑test, Mann–Whitney U‑test, and Fisher’s exact test at the level of significance of P < 0.05.

The mean trabecular thickness in the test group (52.18 ± 5.53) was significantly higher than that in the control group (41.53 ± 10.40) (P = 0.344). However, there were no significant differences in the mean values of vertical bone absorption, bone percentage, remaining biomaterials, inflammation, and blood vessels between the two groups. There was no case of foreign body reaction and the bone was vital in all the cases and in direct contact with the biomaterial.

Although CenoBone® allograft with PRGF was effective in some histomorphometric factors such as trabecular thickness, it did not lead to significant clinical changes.

Panoramic radiography is a standard diagnostic imaging method for dentists. However, it is challenging to detect mandibular trauma and fractures in panoramic radiographs due to the superimposed facial skeleton structures. The objective of this study was to develop a deep learning algorithm that is capable of detecting mandibular fractures and trauma automatically and compare its performance with general dentists.

This is a retrospective diagnostic test accuracy study. This study used a two‑stage deep learning framework. To train the model, 190 panoramic images were collected from four different sources. The mandible was first segmented using a U‑net model. Then, to detect fractures, a model named Faster region‑based convolutional neural network was applied. In the end, a comparison was made between the accuracy, specificity, and sensitivity of artificial intelligence and general dentists in trauma diagnosis.

The mAP50 and mAP75 for object detection were 98.66% and 57.90%, respectively. The classification accuracy of the model was 91.67%. The sensitivity and specificity of the model were 100% and 83.33%, respectively. On the other hand, human‑level diagnostic accuracy, sensitivity, and specificity were 87.22 ± 8.91, 82.22 ± 16.39, and 92.22 ± 6.33, respectively.

Our framework can provide a level of performance better than general dentists when it comes to diagnosing trauma or fractures.

This study aimed to assess the effect of laser irradiation and Tooth Mousse on tooth hypersensitivity (TH) after office bleaching (OB).

This clinical trial, parallel‑design split‑mouth nonrandomized was conducted on 30 patients requiring OB.After scaling and fabrication of a custom tray,35% hydrogen peroxide was applied on all teeth, and 940 nm diode laser (10W,Class IV,110–240V) was irradiated to the upper and lower right quadrants.Laser in off mode was used for the left quadrants.Bleaching agent was then reapplied.After completion of bleaching,a custom tray containing tooth Mousse was placed on the maxillary arch while the tray was used without the paste for the mandibular arch. A visual analog scale was used to assess the degree ofTH at 15 min and 24 h after OB. Data were compared using t‑test, paired t‑test, and analysis of variance. Significance level was set at α = 0.05.

Comparison of TH at 15 min and 24 h after OB showed a significantly lower TH score in the left upper quadrant (tooth Mousse alone) than right upper quadrant (both laser and Tooth Mousse) (P < 0.05).The TH score in the right upper quadrant was significantly lower than that in the right lower quadrant (laser only) (P < 0.05).The meanTH score in the left upper quadrant was insignificantly lower than that in the left lower quadrant (no intervention) (P > 0.05).

The use of 940 nm diode laser for OB increases the postoperativeTH.The application of Tooth Mousse can effectively decrease TH after OB with/without laser irradiation.

The aim of this study was to investigate the effect of bleaching agent, sodium ascorbate as an antioxidant, and delay time on the shear bond strength (SBS) of orthodontic brackets to enamel using Transbond XT and universal adhesive.

In this in vitro experimental study, 80 extracted maxillary premolars without any defect or decay were randomly divided into eight groups of 1: no bleaching +Transbond XT (NB/TX) bonding agent, 2: no bleaching + All‑Bond Universal (NB/AB), 3: bleaching +Transbond XT (B/TX), 4: bleaching +All‑Bond Universal (B/AB), 5: bleaching + sodium ascorbate + Transbond XT (B/SA/TX), 6: bleaching + sodium ascorbate + All‑Bond Universal (B/SA/AB), 7: bleaching +Transbond XT after a 3‑week delay (B/3W/TX), and 8: bleaching +All‑Bond Universal after a 3‑week delay (B/3W/AB). After thermocycling (1000 cycles, 5–55°C), the SBS was measured, and the adhesive remnant index scores were determined to assess the failure mode. Data were analyzed by one‑way analysis of variance, Tamhane’s post hoc test, Kruskal–Wallis, and Mann–Whitney U‑test at the significance level of P < 0.05.

The mean SBS range was 5.5–29.78 MPa. The highest SBS values were related to Group 2 (NB/AB) which were significantly higher than all groups (P < 0.05) and the lowest values were observed in Group 5 (B/SA/TX) which were significantly lower than all groups except Group 3 (B/TX) (P < 0.05).

Bleaching with 40% hydrogen peroxide significantly decreased the SBS of orthodontic brackets, and 10% sodium ascorbate could not reverse the adverse effect of bleaching on SBS. Delaying the bonding procedure by 3 weeks using Universal adhesive considerably decreased the adverse effect of bleaching on SBS and increased the SBS to a clinically acceptable level for orthodontic treatment.

This in vitro study aimed to compare the fracture resistance of fiber post and reversed‑oriented metal post in the restoration of severely decayed primary incisors.

In this in vitro study, forty extracted human primary incisors were sectioned horizontally 1 mm above the CEJ and randomly divided into four groups – Group 1: Central incisors restored with reverse‑oriented metal post, Group 2: Lateral incisors restored with reverse‑oriented metal post, Group 3: Central incisors restored with fiber post, and Group 4: Lateral incisors restored with fiber post. The coronary portion of the teeth was then restored with nanohybrid universal composite. The fracture resistance was measured using universal testing machine. The type of fracture was determined by employing a stereomicroscope. Data were analyzed using two‑way ANOVA test. The level of significance was considered at P < 0.05.

The mean fracture resistance of glass fiber posts (208.00 ± 73.19) was higher than the reverse‑oriented metal posts (190.37 ± 56.36); however, there was no significant difference between any of the groups (P = 0.353).

Within the limitations of this study, it can be concluded that both types of posts studied in the present research can be successfully used in the restoration of severely damaged primary incisors.

Xenogeneic grafts have gained attention due to advantages in compare of autografts. This study aimed to compare Xeno (ostrich) Acellular Dermal Matrix (XADM) with the free gingival graft (FGG) to increase the width of Keratinized gingiva (KGW) in dogs.

This split mouth animal study was performed on 10 mixed breed dogs. The upper second premolar sites were randomly selected for grafting by XADM (test) or FGG (control). Measurements of KGW were recorded before surgery, 1, 3, and 6 months after surgery. Biopsies from grafted sites for histologic and histomorphometric evaluations were harvested 6 months after surgery. Data were analyzed by repeated measured, paired samples t‑test, and Wilcoxon Signed rank test. P < 0.05 was considered statistically significant.

KGW increased in the two study groups after surgery with no significant statistical difference between them at any time intervals (P > 0.05). The graft shrinkage was 23% and 21% for the test and control groups, respectively, without statistically significant difference (P > 0.05). Histomorphometric evaluation showed no significant difference between the two study groups. Foreign body reaction was not seen in any of the study groups.

Increased KWG was similar between the two study groups. With regard to FGG limitations, XADM may be assumed as a suitable alternative for FGG. It should be noted that this research was an animal study and clinical trials on human should be performed to approve the efficacy and safety of this material.