Journal of Research in Dental and Maxillofacial Sciences
Volume:8 Issue: 1, Winter 2023

Different MTA brands may have different push-out bond strength (PBS) values in 10 minutes and 4 hours. Thus, this study aimed to compare the PBS of RetroMTA, OrthoMTA, and ProRoot MTA.  

In this in vitro, experimental study, 54 dentin discs with 2 mm diameter and a central lumen with 1.3 mm radius were used in each of the RetroMTA, OrthoMTA, and ProRoot MTA groups (18 discs for each group). The samples were wrapped in a moist gauze and incubated at 37°C and 100% humidity. The PBS was measured by a universal testing machine at a crosshead speed of 1 mm/minute after 10 minutes and 4 hours. The mode of failure was also categorized by using a stereomicroscope. The mean PBS of the three groups was compared using two-way ANOVA. The mode of failure was analyzed by the Chi-square test.

The interaction effect of time and material on PBS was not significant (P=0.227). At both time points, the PBS of the three groups was significantly different (P=0.001), and RetroMTA showed significantly higher PBS (P<0.014). However, the PBS of OrthoMTA and ProRoot MTA was not significantly different (P=0.695). The PBS of all materials at 4 hours was significantly higher than that at 10 minutes (P=0.001).

RetroMTA was superior to ProRoot MTA and OrthoMTA regarding the PBS after 4 hours.

Discoloration is an unfavorable side effect of regenerative endodontic procedures using mineral trioxide aggregate (MTA). The efficacy of home bleaching of discolored teeth with carbamide peroxide has not been well investigated, and the minimum required duration of home bleaching is still unclear. This study aimed to compare the effects of different durations of home bleaching on tooth discoloration caused by MTA.  

This in vitro, experimental study used 16 tooth blocks of bovine central incisors. To cause discoloration, white MTA was applied for 40 days in cavities drilled in blocks. The color parameters were measured at baseline and at 14, 28, and 42 days after the application of 20% carbamide peroxide using a spectrophotometer. Data were analyzed by repeated measures ANOVA and Tukey’s post-hoc test.

The color change (∆E) value was 22.9±10, 26.3±10.9, and 27.03±11 at 14, 28, and 42 days after bleaching, respectively.Significant color change occurred at 2, 4, and 6 weeks after the application of carbamide peroxide (P<0.001). The color change increased at 42 days (∆E of 3.1, or 13% compared with baseline), which was the highest amount among all time points. However, pairwise comparisons showed that it was not statistically significant (P=0.4).

It appears that 14 days is the required time for bleaching of teeth discolored by MTA. Longer bleaching times showed insignificantly higher efficacy for tooth whitening.

Considering the search for an effective antimicrobial agent comparable to chlorhexidine (CHX), this study aimed to assess the antimicrobial effect of Punica granatum (P. granatum) hydroalcoholic extract on Streptococcus sobrinus (S. sobrinus), Streptococcus sanguinis (S. sanguinis) and Candida albicans (C. albicans), in comparison with CHX.

In this in vitro study, the disc diffusion test was used to assess the antimicrobial activity of the extract by measuring the growth inhibition zones; while, the microdilution and macrodilution broth tests were applied to find the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the extract against the tested microorganisms. The MBC was measured using the blood agar or Mueller Hinton agar culture medium. The Sabouraud dextrose agar culture medium was used for C. albicans. Each test was repeated in triplicate, and data were analyzed by independent samples t-test and Mann-Whitney U test.

None of the tested microorganisms showed any resistance to the extract. CHX had the highest antimicrobial effect against all tested microorganisms. The MIC of the hydroalcoholic extract of P. granatum was 2.5 mg/mL for S. sobrinus and S. sanguinis, and 5 mg/mL for C. albicans. Its MBC was 5 mg/mL for S. sobrinus and S. sanguinis, and 10 mg/mL for C. albicans. The mean diameter of the growth inhibition zone for S. sobrinus caused by CHX was significantly greater than that caused by P. granatum extract (Mann-Whitney U test, P=0.043). The same result was obtained for S. sanguinis (Student sample t-test, P=0.002), and C. albicans (Mann-Whitney U test, P=0.046).

The hydroalcoholic extract of P. granatum has bacteriostatic and bactericidal effects on S. sanguinis and S. sobrinus and antifungal effect on C. albicans comparable to CHX.

The present study compared the retreatment efficacy of D-RaCe, SP1, and R-Endo rotary files in gutta-percha removal from the mesiobuccal canal of mandibular molars by micro-computed tomography (micro-CT).   

In this experimental in vitro study, 30 mandibular molars were prepared with Denco-D-Super files and filled using gutta-percha and AH Plus sealer by the lateral compaction technique. Root canals then underwent micro-CT, and the amount of root filling material was measured on images using LOTUS InVivo-REC software. The teeth were randomly assigned to three groups (n=10) for retreatment with D-RaCe, SP1, and R-Endo systems. They underwent micro-CT again after retreatment, and the volume of residual root filling material in the root canals was calculated. The percentage of cleaning efficiency of each system in removal of gutta-percha from the mesiobuccal canal was calculated and compared among the three groups by two-way ANOVA and Tukey’s test (alpha=0.05).

File type (P=0.05) and root canal region (apical, middle, or coronal third) (P<0.001) had significant effects on the percentage of cleaning efficiency. SP1 was significantly superior to R-Endo regarding cleaning efficiency (P=0.04). D-RaCe had the highest cleaning efficiency in the apical third (85.12%) while SP1 had the highest cleaning efficiency in the middle (91.57%) and coronal (68.22%) thirds. R-Endo had the lowest cleaning efficiency in the entire root canal system.

Although none of the systems had 100% cleaning efficiency, the cleaning efficiency of D-RaCe and SP1 was superior to R-Endo for retreatment of mesiobuccal canal of mandibular molars.

Maintaining the original shape and path of the canal is among the most important criteria for optimal root canal preparation. The aim of this study was to compare the centering ability of F6 SkyTaper and RaCe rotary files in mesiobuccal canals of mandibular molars.  

In this experimental study, 30 mesiobuccal canals of extracted human mandibular molars with 25-30-degree curvature were randomly divided into two experimental groups (n=15) of RaCe and F6 SkyTaper. After mounting of the teeth in a putty mold, the distance between the canal walls and the outer surface of the roots in mesial and distal aspects was measured. The measurements were made at 1, 3 and 7 mm from the apex. Initial glide path in the canals was achieved using a # 15 K-file. Then, the canals in group A were prepared by RaCe rotary file #25/6% while the canals in group B were prepared by F6 Sky Taper rotary file #25/6%. Measurements were repeated and the difference between the two measurements was calculated and compared with the Mann-Whitney U test.

The mean centering ability was 0.72 ± 0.62 in the RaCe group and 0.95 ± 1.39 in F6 SkyTaper group. the centrality was better in F6 SkyTaper group (it was closer to 1) but the difference was not statistically significant (P=0.4).

Both RaCe and F6 SkyTaper rotary systems partially offset the centrality of the root canal system.

This study aimed to compare the effects of emotional self-regulation strategies and systematic desensitization on stress level of adult dental patients.  

The study population included 40 adult dental patients that were selected by purposeful sampling and were classified into two experimental groups of emotional self-regulation strategy (n=20) and systematic desensitization (n=20). Data were collected using a stress questionnaire. The experimental groupsreceived 8 sessions of 90-minute emotional self-regulation strategy and desensitization instructions. Data were analyzed by t-test and paired t-test.

Emotional self-regulation and systematic desensitization affected the stress level of adult dental patients. However, there was no significant difference between the effects of emotional self-regulation and systematic desensitization on stress levels of adult dental patients (P>0.05).

Emotional self-regulation and systematic desensitization instructions equally affected the stress level of adult dental patients in this study.

This study aimed to assess the efficacy of Pistacia lentiscus (P. lentiscus) extract for dentin remineralization.

This in vitro experimental study evaluated 45 extracted sound human premolars; pH cycling was performed to assess the effect of 10% P. lentiscus extract on dentin remineralization. The samples were randomly assigned to three groups of 1000 ppm sodium fluoride (NaF) solution, 10% P. lentiscus extract, and deionized water. To induce dentinal lesions, the teeth were immersed in a demineralizing solution at 37°C for 96 hours.The demineralized samples were then subjected to pH cycling for 14 days, and then underwent the Vickers microhardness test and scanning electron microscopic (SEM) assessment. Data were analyzed by repeated-measures ANOVA.

The mean microhardness in the NaF group was significantly higher than that in the extract and control groups after 14 days (P<0.05). SEM assessment after demineralization indicated tubular obstruction in the extract and NaF groups. However, after 14 days, the sealing of dentinal tubules in the extract group was greater than that in the NaF group.

P. lentiscus extract can serve as a suitable organic compound for dentinal tubule occlusion as well as non-invasive and conservative treatment of dentin hypersensitivity (DH).

A developing odontogenic cyst known as odontogenic keratocyst (OKC) originates from the remains of dental lamina. Its aggressive pattern of expansion and high recurrence rate differentiate it from other odontogenic cysts. Herein, we describe a large OKC in the mandibular ramus, close to the condyle, in a juvenile patient with a third molar crypt.  Age and sex of patient, and size, location, and fast development of this lesion were different compared with previously reported OKCs. Our management strategy aimed to maintain the mandible's natural dentition, form, function, and continuity.   

The conservative strategy of marsupialization and decompression, which results in final total clearance of the cystic lesion, is one of the treatment strategies for OKC. Segmental resection, en bloc, and complex procedures are other treatment options. Surgical enucleation of the lesion and subsequent marsupialization were conducted effectively in this case. After a lengthy follow-up, there was no recurrence.

A detailed comprehension of the nature of the lesion supported by a strong clinical history and cutting-edge radiography may greatly aid the physician in making the appropriate treatment decision for patient's long-term interests.

Periodontitis, as the most prevalent cause of tooth loss, affects 20-50% of individuals throughout the world. One factor involved in the severity and incidence of periodontitis is aging, which is a substantial risk factor for mortality and morbidity. It is stated that some disorders are common in older population, like cardiovascular diseases, osteoporosis, chronic kidney disease, and Alzheimer’s disease. Understanding the changes related to aging may provide a better insight into age-related diseases. Hence, this study aimed to review and summarize evidence regarding periodontitis and aging-related disorders with a mechanistic insight.   

Data were obtained from the scientific databases, including PubMed, Google Scholar, and Scopus in English between 1993 and 2021.

Cardiovascular diseases, osteoporosis, chronic kidney disease, and Alzheimer’s disease are associated with periodontitis directly or indirectly, and pro-inflammatory cytokines are the key mediators in such relationships. For instance, interleukin (IL)-1β, tumor necrosis factor-α (TNF-α), and IL-6 have a substantial role in pathogenesis of periodontitis in the majority of such diseases. These agents, particularly IL-1β and TNF-α, can also lead to leukocyte migration and subsequently form reactive oxygen species (ROS), reactive nitrogen species, and matrix metalloproteinases (MMPs).

 It seems that periodontitis is linked to aging-related diseases, namely cardiovascular diseases, osteoporosis, chronic kidney disease, and Alzheimer’s disease by the mediation of pro-inflammatory agents such as IL-1β, TNF-α, and IL-6.

The purpose of this review was to provide an overview of the use of electromyography (EMG) in dentistry over the past several years, as well as related research. EMG is a sophisticated technique used to detect and analyze muscle activity. EMG was primarily utilized in medical sciences in the past, but it is now widely utilized in both the medical and dental fields.  

Electronic search was conducted in EMBASE, PubMed, Scopus, Web of Science, and Google Scholar to find all clinical studies regarding applications of EMG in dentistry.

This review included 31 papers in all. According to the results, neuromuscular activity may be recorded using EMG for both diagnostic and therapeutic purposes. It could be used in dentistry to evaluate parafunctional habits such as clenching and bruxism as well as muscle activation during actions like chewing and biting. In recent years, the use of EMG in treatment of temporomandibular joint (TMJ) and myofascial pain disorders has significantly increased.

EMG has a variety of applications in dentistry for monitoring, diagnostic, and therapeutic purposes.