Journal of Dentistry, Shiraz University of Medical Sciences
Volume:24 Issue: 2, Jun 2023

Statement of the Problem: 

Dentin hypersensitivity (DH) is a common irritating condition. A precise sensitive test for its assessment can greatly aid in appropriate treatment planning.

This meta-analysis aims to compare the air blast and tactile tests for assessment of the efficacy Nd:YAG laser therapy versus non-laser treatments for DH in short-term and long-term follow-ups.

for this review, an electronic search of the literature was carried out in three databases by two researchers for English articles published until March 10, 2021. Pooling of the data extracted from the selected articles was performed according to the PRISMA statement by the random-effect model. The mean difference (MD) and 95% confidence interval (CI) of pain score before the treatment onset and during the follow-up period according to the visual analog scale (VAS) were calculated. The level of heterogeneity was assessed by the I2 test, and a funnel plot was drawn to assess the publication bias of the reviewed studies.

Of 152 articles primarily retrieved, 9 randomized clinical trials (RCTs) using the air blast test and 4 RCTs using the tactile test were subjected to quantitative synthesis. In the short-term follow-up and immediately after treatment, the air blast test showed superiority of laser therapy compared with non-laser treatments (SMD: 0.55, 95% CI: 0.05-1.04, p= 0.03). However, this difference was not significant according to the tactile test (SMD: 0.48. 95% CI: 0.01-0.96, p= 0.06). In the long-term follow-up, the difference between laser therapy and non-laser modalities was not significant according to both air blast (SMD= -0.38, 95% CI: -1.43-0.67, p= 0.48) and tactile (SMD=0.0, 95% CI: -0.38-0.38, p= 0.99) tests.

Comparison of laser therapy and non-laser modalities in the short-term revealed higher sensitivity of the air blast test due to its mechanism of action compared with the tactile test. Further studies are required to interpret the results in the long-term follow-up.

Statement of the Problem: 

the first molar root location plays a pivotal role in neutralization of forces applied to the teeth to prevent injury.

This study aimed to assess the effect of maxillary and mandibular first molar root location on biomechanical behavior of the periodontium under vertical and oblique loadings.

In this three-dimensional (3D) finite element analysis (FEA), the maxillary and mandibular first molars and their periodontium were modeled. The Young’s modulus and the Poisson’s ratio for the enamel, dentin, dental pulp, periodontal ligament (PDL), and cortical and cancellous bones were adopted from previous studies. The changes in maximum von Misses stress (MVMS) values of each component were analyzed.

The MVMS values were the highest in the enamel followed by dentin, cortical bone, cancellous bone, and PDL. The maxillary and mandibular first molars with different root locations and their periodontium showed different biomechanical behaviors under the applied loads.

An interesting finding was that the stress concentration point in the path of load degeneration changed from the cervical third in dentin to the apical third in the cancellous bone, which can greatly help in detection of susceptible areas over time.

Statement of the Problem: 

Enterococcus faecalis (E. faecalis) is one of the most important microorganisms in the evaluation of the antibacterial effects of intra-canal medications due to its ability to penetrate dentinal tubules and form biofilms. Calcium hydroxide, as the most common intra-canal medication, has little effect on this bacterial species. In contrast, it is hypothesized that nano scale hydroxide particles are more effective due to their smaller size and higher surface-to-volume ratio.

This study aimed to investigate the antimicrobial effect of nano-calcium hydroxide on the four- and six-week-old intra-canal E. faecalis biofilms.

In this in vitro study, seventy maxillary single-canal premolar teeth were used. After cleaning and preparing the root canals, the samples were placed in vials containing E. faecalis solution in which the culture medium was changed daily. Each group was divided into three subgroups (n=20) in terms of the antimicrobial material used as the intra-canal medication including subgroup 1: nano-calcium hydroxide, subgroup 2: calcium hydroxide, and subgroup 3: phosphate-buffered saline solution (control group). The antimicrobial property was measured by counting colony-forming units (CFU). The data were analyzed with Mann-Whitney U and Kruskal–Wallis tests. Statistical significance was set at p< 0.05.

The mean CFU in the six-week-old biofilm group was significantly higher than that in the four-week-old biofilm (p= 0.003). A comparison between the subgroups showed a significant decrease in CFU in the six-week-old biofilm in the nano-calcium hydroxide subgroup compared to that in the calcium hydroxide subgroup (p= 0.002). However, the decrease was not significant in the four-week-old biofilm group (p= 0.06).

Under the limitations of the present study, the antimicrobial properties of nano-calcium hydroxide were higher than conventional calcium hydroxide on mature biofilm, whereas the antimicrobial properties were not clinically and significantly different on immature biofilm.

Statement of the Problem:

 Alveolar ridge resorption after tooth extraction may interfere with optimal dental implant placement.

This study aimed to compare the marginal bone loss (MBL) and thickness of the buccal aspect of the augmented site in simultaneous versus delayed implant placement following lateral ramus horizontal ridge augmentation in the posterior mandible.

This prospective cohort study was conducted on patients who required horizontal bone augmentation of the posterior mandible using lateral ramus autogenous bone graft. Patients were divided into two groups of simultaneous implant placement (group 1) and delayed implant placement (group 2). Cone-beam computed tomography (CBCT) images were obtained before augmentation, at the time of implant placement, and 10 months later (6 months after implant loading). MBL and thickness of the buccal aspect were evaluated over time.

There were 18 patients in the group 1 and 16 patients in the group 2. Analysis of the CBCT scans demonstrated that the mean MBL was 1.21±0.35mm in the group 1 and 1.08±0.19mm in the group 2, with no significant difference between the two groups (p= 0.19). Thickness of the buccal aspect of the augmented site at the time of implant placement was 1.85±0.20mm in the group 1 and 2.16±0.29 mm in the group 2, with a significant difference (p< 0.001). However, data analysis regarding changes in the buccal plate thickness showed no significant difference between the two groups (p= 0.36).

According to the results of this study, there was no significant difference in M-BL and post-operative changes in the thickness of the buccal aspect of the augmented sites with onlay lateral ramus bone blocks between simultaneous and delayed implant placement.

Statement of the Problem:

 Although sumac extract (SE) is reported as a collagen cross linker, the available data regarding its effect on the dentine micro-hardness is quite sparse.

Therefore, the aim of this study includes evaluating the effect of different concentrations of SE on dentine micro-hardness comparing to grape seed extract (GSE).

In this experimental study, the GSE was purchased from available market and convert to 5% solution. Meanwhile the 5, 10, and 20% of SE solutions were prepared experimentally. The base line micro-hardness of 60 samples (30 premolars divided to buccal and lingual segments) was recorded triplicate for each specimen and they were randomly divided into 5 groups (four abovementioned experimental solutions and de-ionized water as negative control). For 35 consecutive days, each sample was twice pH cycled and treated by solutions. Ultimately, the final micro-hardness was recorded triplicate again for each sample and the numerical data was compared with each other using one-way ANOVA and Tukey HSD Post Hoc tests (α=0.05).     

The mean±SD values of micro-hardness for the groups was recorded as 54.45± 13.4, 65.65±18.5, 39.57±2.26, 41.13±1.66 and 43.79±4.96 at base line and 10.4±0.99, 11.85± 0.75, 10.16±1.84, 8.48±1.16 and 6.31±1.01 at final stage for control, GSE 5%, SE 5%, SE 10% and SE 20% respectively. There was no significant difference among the micro-hardness of the groups before treatment (p= 0.369). However, after experimental treatment, there was significant difference between the groups (p= 0.024) while in pairwise comparison just two groups (GSE 5% and SE 20%) had significant difference with each other (p= 0.017).

The efficacy of SE was reversely related to its concentration. Moreover, neither GSE nor SE had significant effect on dentine micro-hardness after 35 day pH cycling.

Statement of the Problem: 

Determining the prevalence of respiratory viruses' coinfection with coronavirus disease 2019 (COVID-19) is essential to defining its true clinical influence.

This study aimed to evaluate co-infection rates between severe acute respiratory syndrome–related coronavirus 2 (SARS-CoV-2) and respiratory syncytial virus (RSV) in infected patients in Shiraz, south of Iran.

In a cross-sectional descriptive study, oropharyngeal, nasopharyngeal aspirate (NPA), and saliva samples of 50 COVID-19 patients who were referred to Ali-Asghar hospital (Shiraz, Iran) from March to August 2020, were collected. A control group consisted of age and sex-matched healthy participants. The nasopharyngeal and oropharyngeal aspirates were collected by sterile swabs. All cases were hospitalized, and all SARS-CoV-2 patients had a fever and respiratory symptoms. The samples were packed in a vial with 1 mL of transport medium and transported to the Valfagre specialty laboratory, where they were tested for RSV using a real-time polymerase chain reaction (PCR).

100 nasopharyngeal/oropharyngeal aspirates and saliva samples including 50 healthy controls (24 females, 26 males) and 50 COVID-19 patients' samples (27 males and 23 females) were studied. There was no significant difference regarding age as well as gender between both groups (P>0.05). None of the healthy subjects was infected with RSV; however, 5(10%) patients from COVID-19 group were infected with the RSV virus. Chi-square test did not show a significant difference between RSV infection in COVID-19 patients and healthy subjects.

The outcome of present research showed that concurrent RSV with COVID 19 infection might be seen in hospitalized patients in Shiraz Southwest of Iran. For more reliable findings, further research on bigger populations, including more pathogens in several places around the country, and considering the severity of symptoms is required.

Statement of the Problem: 

The bone particles collected during osteotomy could be used as autogenous bone graft materials for dental implant surgery. Different factors such as drill design may influence its clinical viability.

This study examined the effect of drill design on the osteoblast viability and histopathology parameters of bone collected during the preparation of dental implant site.

In this experimental study, 90 samples were obtained from three different bone drilling systems including Bego, Implantium, and Dio during fixture installation in patients requiring treatment at the Department of Periodontology, Dentistry University Hamedan. The MTT (3-4,5-Dimethylthiazol2,5-diphenyltetrazolium bromide) was used to determine percentage of cell viability. Samples were fixed in 10% formaldehyde for histological evaluation. Then, they were kept in 10% EDTA solution for 4 weeks for decalcification. The provided slides were evaluated regarding bone structure and osteocytes counts for assessment of viability. Tukey test and SPPS 21 software were used for statistical analysis.

The result showed the viability of osteoblast obtained by Dio (0.45±0.04) was significantly better than Bego (0.37±0.05) and Implantium (0.37±0.04) systems. In histopathological evaluation, the grafting material obtained by Dio presented the best osteoblast morphology.

It might be concluded that drill geometry has significantly influenced the viability of bone particles collected during the preparation of implant sites .Moreover, characteristic geometry alone cannot represent the performance of a particular drill, and several geometric features should be concerned. The results of this study showed that the geometry of the Dio drill was the best considering the viability and histopathological evaluations.

stement of the Problem: 

Due to the unfavorable properties of eugenol, the eugenol content can be reduced to improve the properties of zinc oxide eugenol (ZOE) by making a new combination of nanocurcumin called curcumin pulpal paste (CPP).

The aim of this in vitro study was to evaluate the solubility and tooth discoloration of three concentrations of CPP compared to ZOE, and Metapex.

In this in vitro study for evaluating of the solubility, five groups including ZOE, Metapex, and three concentrations of CPP (5%, 10%, and 20%) were tested. For evaluating the solubility, the changes in of the weight of samples were measured at 1, 3, 7 and 30 days after initial setting. In order to evaluate the tooth discoloration, 75 bovine maxillary anterior teeth were filled with one of five pulpal pastes. The changes in tooth color were evaluated at 1 hour, 1 week, 1 and 3 months after material placement.

The solubility increased by increasing the nano-curcumin percentage in CPPs. After 30 days, the solubility of the 5%CPP, and ZOE was not significantly different (p= 1.000). According to the colorimetric test, after 3 months, the highest discoloration was recorded for 20%CPP (8.45), and the smallest discoloration was registered for Metapex (4.06). The discoloration of 5%CPP, and 10% CPP was similar to ZOE’s color change (p> 0.05).

The results of the present study showed that the solubility of pulpal paste has increased with increasing curcumin concentrations. Therefore, pulpal paste with different nanocurcumin concentrations can be used considering the patient's age and the desired time of deciduous tooth loss, and dissolution of pulpal paste. Concerning the discoloration after 3 months, Metapex was the best material and the most discoloration rate was related to 20%CPP, and there was no difference between the 5% CPP, and 10% CPP with ZOE.

Statement of the Problem:

 Currently, the reconstruction of bone defects with new platelet concentrates is considered a significant challenge in periodontics.

This study aimed to evaluate advanced- platelet rich fibrin (A-PRF) and leukocyte- and platelet rich fibrin’s (L-PRF) effects on the proliferation and differentiation of MG-63 cells.

In this in vitro study, blood samples of five healthy non-smoking volunteers were collected and immediately centrifuged according to the two protocols of Choukroun and Ghanaati, without adding any anticoagulants, to prepare L-PRF and A-PRF. After freezing the clots for one hour, they were crushed and centrifuged once more. After culturing MG-63 cells, the effects of 20%, 10%, 1%, and 0.5% concentrations of A-PRF and L-PRF extracts on cell proliferation and mineralization were evaluated by methyl thiazolyl tetrazolium (MTT) assay and Alizarin Red staining, respectively.

Generally, survival and proliferation in the L-PRF group at both time intervals were higher than the A-PRF group and increased with increasing the extract concentration. However, in the A-PRF group, there were no significant differences between the different concentrations, and only the number of cells increased over time. After three days, in the study on mineralization, nodule formation was observed only in the positive control group (osteogenic). In seven days, mineralized nodules were formed in all groups with different concentrations of A-PRF, but not in any of the L-PRF groups.

According to the results, L-PRF increased proliferation, and A-PRF exerted a positive effect on the differentiation of MG-63 cells.

Statement of the Problem: 

Mast cells are round to elliptical cells that originate from bone marrow stem cells and enter the peripheral blood. By releasing inflammatory mediators, these cells are involved in type I hypersensitivity, wound healing, defense against pathogens, increased blood vessel formation, and destruction of the extracellular matrix. There are contradictory results regarding the role of mast cells in tumor lesions.

Considering the contradictory results and few studies on the density of mast cells in salivary tumors, the present study investigated and compared the density of mast cells in two common salivary gland tumors.

In the cross-sectional study after reviewing the records of patients referred to the Pathology Department of the School of Dentistry and Shahid Sadoughi Hospital in Yazd, 15 blocks of each of the mucoepidermoid carcinoma and pleomorphic adenoma tumors were taken. After Giemsa staining of the samples, the average of stained cells in 10 random fields under 400× magnification was counted. The results were analyzed using statistical tests of t-test, ANOVA, Chi-square, and Mann-Whitney in SPSS ver. 22.

The average mast cell counts in pleomorphic adenoma (4.2) was higher than muco-epidermoid carcinoma (1.7) but there was no significant relationship (p= 0.305). In mucoepidermoid carcinoma, the numbers of mast cells increased with increasing tumor grade (low: 0/467 moderate: 1/567 high: 2/983) and there was a significant relationship (p= 0.009).

According to the results of the present study, it seems that the mast cells accumulation may be secondarily associated with inflammatory responses due to cell accumulation and tissue destruction by tumor cells.

Massive cystic lesions involving a mandible always present a diagnostic and treatment challenge. Unicystic ameloblastoma (UA) is a variant of ameloblastoma encompassing about 6% of ameloblastomas. They represent cystic lesions that reveal clinical and radiographic features of a cyst, but the histopathological features demonstrate a typical ameloblastomatous epithelium lining the cyst. It is a variant of ameloblastoma, usually having clinical and radiographic similarities with dentigerous cysts, hence posing preoperative diagnostic difficulties. Adult treatment protocol cannot be applied to the pediatric population since resection may cause an alteration in craniofacial development leading to functional and esthetical damage, which can directly affect their quality of life. A more conservative approach of enucleating the lesion seems to be a promising treatment modality of UA in the pediatric age group. We present a case of mural variant of UA arising from dentigerous cyst in an 8-year-old male patient.

Rosai Dorfman disease is generally defined as a massive bilateral painless cervical lymphadenopathy accompanied with both fever and leukocytosis with neutrophilia. Additionally, it may possibly be associated with polyclonal hypergammaglobulinemia, reversal of CD4/CD8 ratio, the elevated erythrocyte sedimentation rate (ESR), microcytic anemia, and thrombocytosis. Rosai-Dorfman disease is known as a benign self-limiting disease, so no treatment is required in many cases, although it causes death in some cases by involving vital organs like kidney. The treatment is required when there is a life-threatening situation such as airway obstruction or involvement of vital organs such as kidney, liver, and lower respiratory tract. The required treatment choices include steroid therapy, chemotherapy, radiotherapy, and surgery. Surgical treatment is performed for bulk removal to resolve the obstruction caused by the mass as well as taking biopsy for the definite histopathologic diagnosis of disease. A 26-year-old man was referred to oral and maxillofacial surgery (OMFS) clinic of Taleghani hospital with chief complaints of pain and swelling of left submandibular space. According to the patient himself, the swelling had been started three months earlier. After rejecting dental source of the lesion, we decided to remove the mass by excisional biopsy concerning the patient’s discomfort. Histopathology report verified Rosai Dorfman disease as definite diagnosis of the mass.