Journal of Dentistry, Shiraz University of Medical Sciences
Volume:26 Issue: 1, Mar 2025

Statement of the Problem: 

Temporomandibular joint disorder (TMD) will appear if there is a problem with the temporomandibular joint, bones, related muscles, or ligaments. This complication causes severe joint pain near the ears, head, neck, and jaws. TMD has been reported to affect 40 to 70% of adults.

Based on previous studies, the present review aimed to determine the prevalence of TMD among the Iranian population.

This review and meta-analysis was performed according to the PRISMA guidelines. All relevant studies published during 2000-2023 were retrieved by a systematic search in available international databases, including Web of Science, Science Direct, Scopus, PubMed, and Google Scholar, and domestic Persian databases, including SID, Magiran, and Iran Medex. Finally, 22 completely related studies were selected to investigate the main objective. The Comprehensive Meta-analysis (CMA) software was used for data analysis in this systematic review.

Initially, 212 articles were retrieved, of which 116 were duplicate studies. Further, 39 studies were excluded after evaluation of the title and abstract, and 35 studies were excluded after considering the inclusion and exclusion criteria. Finally, 22 articles were included in the meta-analysis. The pooled prevalence of TMD in Iran was 0.56 (0.44-0.68).

In general, the prevalence of TMD in the Iranian population is relatively high. Therefore, it is necessary to develop strategies to educate people, especially those at risk. Furthermore, due to the presence of TMD in children and students in some parts of the country, it is necessary to perform essential examinations in preschools to prevent the development of this disorder in later life.

Stainless steel crowns (SSCs) are the preferred choice for restoring primary molars with extensive caries. However, they may be indicated for permanent molars in certain cases as well. While limited research assessed different aspects of this treatment separately, this review aims to consolidate the existing literature and provide a multi-dimensional analysis of preformed metal crown restoration for permanent molars. A comprehensive search of electronic databases including Pubmed, Scopus, Web of Science, Embase, and Cochrane was conducted, and relevant studies were categorized based on specific aspects of this treatment including indications, survival rates, periodontal and radiographic findings, utilization frequency, and alternative options. The review highlights the wide range of indications for SSCs on permanent molars of children, adolescents, and even adults, along with their remarkable success rates. However, noticeable underutilization, despite their proven efficacy, was observed. Periodontal defects and marginal discrepancies were found to be the most common causes of failures.

Statement of the Problem:

 Opportunistic infections such as Pseudomonas aeruginosa, colonized from the oral cavity, are common in candidates of bone marrow transplantation. Therefore, it is important to prescribe appropriate antibiotics for this group of debilitated patients.

In this study, we aimed to investigate the antibiotic resistance to Pseudomonas aeruginosa encountered in candidates of bone marrow transplantation referred to Imam Reza Clinic, Namazi Hospital, and Amir Hospital, Shiraz, Iran.  

This cross-sectional study was performed on 30 patients with leukemia and lymphoma. To identify Pseudomonas species, saliva samples were collected and cultured in a blood agar medium. Considering the present therapies, we examined the antibiotic sensitivity of Penicillin, Oxacillin, Gentamicin, Tetracycline, Cefepime, Ciprofloxacin, Imipenem, Ceftazidime, Cefotaxime, Erythromycin, Trimethoprim, Sulfamethoxazole, and Vancomycin. Statistical analysis was performed using chi-square test (χ2) and SPSS software. P value < 0.05 was considered significant.

In 10 patients out of 30 for whom Pseudomonas aeruginosa was found positive (33.33%), all cultures were resistant to Penicillin and Oxacillin (100%), followed by Trimethoprim and Sulfamethoxazole (80%). The best performance was seen by Vancomycin (20%). No correlation was found in terms of age, gender, and type of disease (lymphoma or leukemia) for antibiotic resistance (p> 0.05).

It seems that Penicillin, Oxacillin, Tetracycline, Sulfamethoxazole have significant resistance to Pseudomonas aeruginosa. Further research on Gentamicin, Ceftazidime, Ciprofloxacin, and especially Vancomycin is recommended for effective antibiotic prescriptions against Pseudomonas aeruginosa.

Statement of the Problem: 

Oral squamous cell carcinoma (OSCC) is the eighth leading cause of cancer-related death worldwide. JAK2 and STAT3 primarily influence intrinsic tumor cell behavior, and CTLA4 impacts the interplay between the tumor and the host immune system in the context of cancers. There is scarce information regarding the involvement and roles of JAK2, STAT3, and CTLA4 genes in OSCC; however, the molecular mechanisms are still unclear.

This study examined the relationship between JAK2, STAT3, and CTLA4 gene expression levels and OSCC in a group of patients in the southeast of Iran.

This cross-sectional study was conducted in which the relative gene expression levels of JAK2, STAT3, and CTLA4 were compared between 23 oral paraffin tissue blocks collected from OSCC patients and 20 fresh gingival tissues collected from healthy individuals. The Real-Time quantitative PCR (RT-qPCR) assay was employed to assess relative gene expression levels. SPSS 27 was employed to perform statistical analyses.

Significant differences were found between OSCC patients and healthy individuals concerning gene expression levels of JAK2 (2.4-fold, p< 0.0001), STAT3 (2.32-fold, p< 0.0001), and CTLA4 (4.09-fold, p< 0.0001). Additionally, there were significant positive correlations among JAK2-STAT3 (0.667, p< 0.001), JAK2-CTLA4 (0.771, p< 0.001), and STAT3-CTLA4 (0.635, p= 0.001) co-expressions. Moreover, gender, age groups, and tumor locations did not significantly correlate with the expression levels of these genes (p> 0.05). Nevertheless, significant differences occurred between histopathological grades and the gene expression levels of JAK2 (p< 0.001), STAT3 (p= 0.001), and CTLA4 (p< 0.001).

The overexpression of JAK2, STAT3, and CTLA4 can be considered triggers for OSCC development. It may be beneficial to conduct future research on OSCC by considering downstream genes involved in the JAK2/STAT3/CTLA4 axis.

Statement of the Problem: 

Despite the prevalence of CL.II malocclusion, still the best mechanotherapy for non-extraction treatment is not verified.

The aim of the present study was to evaluate the stress distribution and tooth displacement during maxillary molar distalization with the aid of two different constructions of jigs in three different lever arm heights.

In this finite element study, models were meticulously constructed to represent the maxillary arch teeth (excluding the third molar), periodontal ligament, alveolar bone, maxillary brackets, main archwire, molar bands, jigs, and mini screws. These models were imported into Ansys software for simulation and analysis. Two different jig configurations with three different lever arm height were created. A 150-gram force was applied to simulate tooth movement, facilitate observation, and analyze its effects on oral components.

In various experimental configurations involving tow jigs with differing lever arm heights, the central incisor exhibited displacement characterized by lingual and distal crown tipping, along with evidence of intrusion. Concurrently, the first molar displayed lingual and distal tipping, as well as extrusion, across six distinct modalities.

In the main, posterior teeth showed distal and lingual tipping and extrusion and anterior teeth demonstrated intrusion mesial and lingual tipping in all models. It seems the differences were due to different lever arm heights. Two types of jig had no significant effect on stress distribution and tooth movement.

Statement of the Problem: 

One of the most important stages of root canal treatment is obturation for the root canal, an obturation with less voids will have fewer treatment complications in the future.

This study was conducted to compare the quality of obturation of single-canal maxillary second premolars by the cold lateral compaction (CLC) versus continuous warm vertical condensation (CWVC) techniques using micro-CT.

In this experimental study, 36 extracted single-canal maxillary premolars were selected. The root canals were instrumented by Denco Blue rotary files. The teeth were randomly assigned to three groups (n=12) of control (no root filling), root canal obturation with CLC technique, and root canal obturation with CWVC technique. Next, they underwent micro-CT, and the mean volume and volume percentage (VP) of voids were calculated in the apical, middle, and coronal thirds of the root canals. Data were analyzed using one-way ANOVA, the Kruskal-Wallis, Mann-Whitney U, Bonferroni, Dunnett, Tukey, and independent t-tests (p Value<0.05)

In the coronal third, no significant difference was found between the CLC and CWVC groups in the mean volume of voids (p= 0.273), the mean volume of filled space (p= 0.419), or the VP of voids (p= 0.605). The highest mean volume and VP of voids were recorded in the coronal part of the group CWVC (p> 0.05). The lowest mean volume and VP of voids was recorded in the apical third in CWVC group (p< 0.05).

None of the obturation techniques could provide a void-free root filling. Two techniques showed no significant difference regarding the mean volume and VP of voids in obturation of single-canal maxillary second premolars.

Statement of the Problem: 

Tooth development is initiated by localized thickenings of the primary epithelial bands. Dentin sialophosphoprotein (DSPP) is the most abundant non-collagenous protein in the dentin matrix. DSPP's expression extends to multiple tissues, including dentin, cementum, and bone. However, the role of DSPP is not yet clear in the development of human tooth.

The current study aimed to examine the DSPP expression profile during the development of human primary tooth structures with a sufficiently large sample size.

In this experimental study, a total of 33 samples of aborted human fetuses were divided into three age groups: <16 weeks, <19 weeks and ≥19 weeks. Immunohistochemistry (IHC) was performed with Anti-DSPP rabbit polyclonal antibody. A two-way ANOVA analysis was conducted to examine the differences between the groups (p< 0.05).

An increase in DSPP expression was observed with the progression of gestational weeks in different histological structures of developing human primary teeth.

An increase in the expression level of DSPP with the progression of gestational weeks may confirm that reciprocal interactions between the enamel organ (EO) and dental pulp cells contribute to tooth formation.

Statement of the Problem: 

The retention of dental crowns plays a pivotal role in their long-term success and maintenance. According to the ongoing controversy about the effect of GLUMA desensitizer and diode laser on the retention of full metal crowns, this study seeks to investigate the effectiveness of two different methods in enhancing the bond strength of full-metal crowns.

This study was developed to compare the effect of 940nm diode laser and GLUMA desensitizer on the bond strength of full-metal crowns cemented by self-adhesive resin cement (RelyX U200).

In this experimental study, 30 sound permanent maxillary first premolars were prepared; a 0.5-0.7 mm chamfer finish line was prepared above the cementoenamel junction. The teeth were randomly divided into three groups: 1. control group (n=10, no treatment) 2. 940nm diode laser (N=10) 3. GLUMA desensitizer (N=10). All crowns were cemented with self-adhesive resin cement (RelyX U200), and the bond strength was measured by universal testing machine. Data were analyzed by ANOVA and Post HOC Tukey test in SPSS Ver:20.

Crown retention in the 940 nm diode laser group (166.86±34.25 N) was significantly lower than the GLUMA desensitizer group (318.59±56.31 N) (p< 0.05), but there was no significant difference with the control group (138.17±40.81). Crown retention in the GLUMA desensitizer group was significantly higher than the other groups (p< 0.05).

Results of this study showed that GLUMA desensitizer had a positive effect, and 940 nm diode laser had no effect on the retention of crowns cemented by self-adhesive resin cement.

Statement of the Problem:

 In the literature, the relationship between sleep quality and periodontal diseases has been mentioned, but still there is a lack of consensus and a valid conclusion in the results obtained.

This study aimed to compare the sleep quality of patients with periodontitis and their healthy counterparts. The correlation between sleep quality score and age, gender, occupation, brushing pattern, and the severity of periodontal disease was also investigated.

This case-control study was conducted on 106 patients with periodontitis and 106 controls with healthy periodontium referring to the Periodontology Department of Yazd Dental School from December 2021 to April 2022. The sleep quality of the two groups was assessed by the Pittsburgh Sleep Quality Index (PSQI). Data were analyzed by ANOVA, t-test, and linear regression to assess possible correlations between the sleep quality score and demographic variables, tooth brushing pattern, and presence of periodontitis and its severity (alpha=0.05).

Totally, 149 females (70.3%) and 63 males (29.7%) with the mean age of 34.17±8.29 years, participated in this study. The sleep quality score had no significant correlation with age, gender, occupation, or tooth brushing pattern (p> 0.05). However, the sleep quality had a significant correlation with periodontitis (OR= 1.15, CI 95%: 1.02-1.29, p= 0.01). The sleep quality score had no significant correlation with the severity of periodontal disease (p= 0.225).

Sleep quality of patients with periodontitis was significantly lower than that of healthy controls.

Statement of the Problem: 

Employing different instruments may have different impact on the outcome of root canal treatments. Deviation from the original canal path and defective root canal obturation may lead to pulpectomy treatment failure.

This study compared the primary molar canal transportation, centering ability, and obturation quality of hand files, Mtwo, Reciproc, and Gentlefile rotating machines in root canal treatments.

In this in vitro experimental study, eighty primary molar roots were randomly assigned to four groups. Cone-beam computed tomography (CBCT) scans were provided for the samples, and hand files (group 1), Mtwo (group 2), Reciproc (group 3), and Gentlefile (group 4) were used to instrument the root canals. Once more, CBCT scans were acquired, and at 1, 2, and 3mm from the apex as well as 1 mm from the orifice, the canal transportation and centering ability were evaluated in buccolingual and mesiodistal directions. Zeolite (ZOE) cement was used to obturate every root canal. To evaluate the obturation density, number of voids, and underfilling in each group, new CBCT scans were obtained. For every tooth, the maximum, minimum, and average Hounsfield units (HU) were noted. One-way ANOVA, the Kruskal-Wallis test, and Tukey's HSD test were used to analyze the data.

Mtwo exhibited considerably superior centering ability than Gentlefile at 2mm from the apex in the mesiodistal direction (p Value< 0.05). Gentlefile had significantly higher buccolingual canal transportation than Reciproc at 3 mm from the apex (P0.05). Minimum HU, underfilling, and void numbers did not differ amongst the four groups (p= 0.791, p= 0.1, and p= 0.548). Reciproc had substantially higher maximum and average HU, followed by Mtwo, Gentlefile, and hand files (p< 0.05).

When compared to other systems, Gentlefile showed higher transportation and less centering ability. Reciproc had the highest obturation density, followed by Mtwo, Gentlefile, and hand files.

In the present study, we reported a 66-year-old woman with an uncommonly painful calcifying odontogenic cyst (COC) in the posterior region of the left side of the maxilla. The cyst was evaluated radiographically and histopathologically. The present case showed a multilocular cyst with a mixed internal structure. The most noticeable effects on the peripheral structures were elevated maxillary sinus floor, osteomeatal complex, and nasal obstruction. To better understand the impact of COC on the trabecular pattern of the surrounding bone, we performed fractal analysis on the panoramic images pre- and post-operatively. The expansion of COC can change the trabecular pattern, which subsequently can change the fractal dimension of the area. After histopathological confirmation of the diagnosis, the cyst was surgically removed.

Retrievability of cement-retained implant-supported prosthesis in the event of abutment screw loosening is a challenging task, and the most common arbitrary drilling technique to retrieve the prosthesis can cause extensive irreversible damage. A 37-year-old male patient reported a chief complaint of a mobile implant-supported prosthesis in the left upper back tooth region. Past dental history revealed that the patient had underwent replacement of missing 27 using cement-retained implant-supported prosthesis 4 years ago using digital impression technique and Computer Aided Designing-Computer Aided Manufacturing (CAD-CAM) milling. This case report describes a novel technique to locate the screw access channel and fabrication of three-dimensional (3D) printed guide template that retrieved the cement-retained prosthesis utilizing the stored digital imaging data. The technique involves designing of the virtual model, screw access channel locator, and prosthesis using CAD technology with the digital impression made during prosthesis fabrication.

Dear Editor “Odontogenic Tumors: A Challenge for Clinical Diagnosis and an Opportunity for AI Innovation. [1]” is informative and we would like to comment on this article.  In this article, the authors discussed the challenges associated with clinical diagnosis of odontogenic tumors and highlighted the potential for artificial intelligence (AI) innovation in this field. While the authors did well in emphasizing the complexities of diagnosing these tumors and the need for advanced technology, they could have provided more details on the specific types of odontogenic tumors that pose the greatest challenges for diagnosis. Additionally, a more thorough exploration of the current limitations in diagnosing these tumors would have provided a more comprehensive understanding of the issue. Moving forward, future research should focus on developing AI algorithms that can accurately differentiate between different types of odontogenic tumors based on their unique characteristics. By incorporating advanced imaging techniques and machine learning algorithms, researchers can improve the accuracy and efficiency of diagnostic processes. Moreover, studies should also investigate the potential benefits of using AI in treatment planning and monitoring of odontogenic tumors to enhance patient outcomes. In terms of recommendations, it is essential for healthcare professionals to receive adequate training and education on the latest advancements in AI technology for diagnosing odontogenic tumors. Collaboration between dental professionals and AI experts is crucial in developing innovative solutions that can streamline the diagnostic process and improve patient care. Additionally, further research should be conducted to evaluate the cost-effectiveness and feasibility of implementing AI- based diagnostic tools in clinical practice. Combining AI with other cutting-edge technologies, such as genomics and proteomics, could be a different and possibly more successful method of examining odo-ntogenic malignancies. By integrating these several fields of study, scientists can develop more accurate dia-gnostic and therapeutic approaches by gaining a deeper comprehension of the molecular pathways driving odontogenic malignancies. In the future, this multidisciplinary approach has the potential to drastically enhance patient outcomes and transform the dental industry.

Dear Editor We appreciate the insightful feedback on our article discussing the complexities and potential innovations in diagnosing odontogenic tumors through artificial intelligence (AI). The commenter rightly points out the need for a more detailed exploration of specific types of odontogenic tumors that present significant diagnostic challenges. While our article aimed to provide a broad overview of the diagnostic complexities across various tumor types, we acknowledge that a deeper dive into individual tumor characteristics and diagnostic hurdles would have enriched the discussion. Moving forward, we recognize the importance of focusing research efforts on developing AI algorithms that can effectively differentiate between different types of odontogenic tumors based on their unique clinical and radiographic features. By integrating advanced imaging modalities and machine learning algorithms, researchers can indeed enhance diagnostic accuracy and efficiency, thereby improving patient outcomes. Additionally, we agree with the commenter’s recommendation regarding the necessity for healthcare professionals to receive adequate training in AI technology. Collaboration between dental practitioners and AI specialists is essential for harnessing the full potential of AI in improving diagnostic precision and streamlining treatment planning for odontogenic tumors. Moreover, we appreciate the suggestion to explore interdisciplinary approaches by integrating AI with genomics and proteomics. This holistic approach holds promise for advancing our understanding of the molecular mechanisms underlying odontogenic malignancies, which could lead to more targeted and effective therapeutic strategies in the future. In conclusion, we thank the commenter for their constructive critique and valuable recommendations. Moving forward, we are committed to addressing these points in future research endeavors to further advance AI-driven innovations in the diagnosis and management of odontogenic tumors.