JOURNAL OF DENTISTRY (SHIRAZ UNIVERSITY OF MEDICAL SCIENCES)
Year:2018 | Volume:19 | Issue:2|Papers Count:12

Statement of the Problem: Accurate measurement of the available bone height is an essential step in the pre-surgical phase of dental implantation. Panoramic radiography is a unique technique in the pre-surgical phase of dental implantations because of its low cost, relatively low-dose, and availability. Purpose: This article aimed to assess the reliability of dental panoramic radiographs in the accurate measurement of the vertical bone height with respect to the horizontal location of the alveolar crest. Materials and Method: 132 cone-beam computed tomography (CBCT) of the edentulous mandibular molar area and dental panoramic radiograph of 508 patients were selected. Exclusion criteria were bone abnormalities and detectable ideal information on each modality. The alveolar ridge morphology was categorized into 7 types according to the relative horizontal location of the alveolar crest to the mandibular canal based on CBCT findings. The available bone height (ABH) was defined as the distance between the upper border of the mandibular canal and alveolar crest. One oral radiologist and one oral surgeon measured the available bone height twice on each modality with a 7-dayinterval. Results: We found a significant correlation between dental panoramic radiographs and cone-beam computed tomography values (ICC=0. 992, p< 0. 001). A positive correlation between the horizontal distance of the alveolar crest to the mandibular canal and measured differences between two radiographic modalities had been found (r=0. 755, p< 0. 001). For each single unit of increase in the horizontal distance of the alveolar crest to the mandibular canal, dental panoramic radiographs showed 0. 87 unit of overestimation (p< 0. 001). Conclusion: Dental panoramic radiographs can be employed safely in the pre-surgical phase of dental implantation in posterior alveolus of mandible, especially in routine and simple cases.

Statement of the Problem: Pit and fissure sealant placement is considered as an effective modality for prevention of caries on occlusal surfaces. Penetration, retention and lateral wall adaptation are the key factors in success of pit and fissure sealant restorations. Purpose: The purpose of this paper was to compare penetration ability and lateral wall adaptation of three commercially available pit and fissure sealants. Materials and Method: The present in-vitro study was done on 45 extracted sound human molars to evaluate the fissure pattern and assess the penetration ability of three commercially available sealants [Delton® FS Sealant (Dentsply DeTrey GmbH, Konstanz, Germany), Clinpro™ Sealant (3M™ ESPE™ , Minnesota, USA) and GC Fuji VII Glass Ionomer Cement (GC Asia Dental Pte Ltd, Singapore)] on molars divided into 3 equal groups of 15 each, with further sectioning of each sample into 2 parts giving 30 samples per group. Following thermocycling and embedding of teeth in clear auto-polymerizing acrylic resin, sections were evaluated for fissure morphology, sealant penetration, unfilled space, lateral wall adaptation, and for presence of voids. Results: Penetrability of all the sealants studied was found to be significantly more in U-type fissure pattern (93. 89%) followed by V-type (78. 62%), IK-type (74. 34%) and then in I-type (65. 91). The depth of penetration of the GC Fuji VII Glass Ionomer sealant (85. 82%) was found to be superior followed by unfilled resin sealant (Clinpro™ Sealant-78. 26%) and then by filled resin sealant (Delton® FS Sealant-74. 89%). Conclusion: U-type fissure pattern was more common than other fissure patterns and showed significantly higher penetrability of different type of sealants evaluated in the present study. GIC based sealant, due to significantly higher penetration depth than unfilled and filled sealants used in the present study, can be preferred over filled or unfilled resin sealants.

Statement of the Problem: Dental caries, the most common infectious disease, can lead to several consequences, including inflammation and bleeding of the gum, abscess formation, tooth loss, and subsequently loss of available space in the arch. Purpose: This study was designed to determine dental caries status of Shiraz preschool children and its related factors. Materials and Method: This cross-sectional study was conducted on the children registered in Shiraz kindergartens in 2014. The study recruited 453 children by randomized cluster sampling. We evaluated the children’ s demographic and oral hygiene factors, and their dental caries status using decayed, missed, and filled tooth (dmft) index and prevalence of the children with untreated dental caries. Relationship between the children’ s characteristics and their dental caries status was evaluated. Results: Only 119 children (30. 1%) were caries-free. The children’ s mean dmft index was 3. 88(± 3. 9). After controlling the effect of confounding factors, the children’ s dental caries status was significantly associated with variables indicating their socioeconomic status such as fathers’ job, mothers’ education, and number of children in the family. Furthermore, there was a significant association between the children’ s dental caries status and their oral hygiene habits such as frequency of tooth brushing. Conclusion: The dental caries status of the studied preschool children was not desirable which could be indicative of the inadequacy of the current preventive programs. To improve this issue, interventional preventive programs such as tooth brushing are recommended. The programs are more necessary for the children of low socioeconomic families and those with poor oral hygiene habits.

Statement of the Problem: Genetic polymorphisms can alter immunity response against pathogens, which in turn influence individuals’ susceptibility to certain infec-tions. Purpose: Our aim was to determine the association of Arg753Gln (rs5743708) and Arg677Trp (rs12191786) polymorphisms of toll like receptor-2 gene with the two clinical forms of apical periodontitis: acute apical abscess (AAA) and asymptomatic apical periodontitis (AAP). Materials and Method: There were 50 patients with AAA as case group and 50 with AAP as control group. Genotyping was done using Tetra-ARMS (amplification re-fractory mutation system) PCR. Results: Heterozygous genotype of Arg677Trp polymorphism was associated with risk of AAA (OR=1. 9, 95% CI: 0. 7-5. 5, p= 0. 05). Although statistically insignificant, Arg677Trp polymorphism promoted the risk of AAA in dominant model (OR=2. 1, 95% CI: 0. 7-5. 9, p> 0. 05). The frequency of mutant allele (T) of Arg677Trp poly-morphism was higher in AAA (14%) than AAP (7%) subjects (OR=1. 7, 95% CI: 0. 6-4. 7). For Arg753Gln polymorphism, wild homozygous (GG) represented the domi-nant genotype in both cases (96%) and controls (100%). Variant allele (A) of Arg753Gln polymorphism was identified in 2% of AAA, while no individual repre-sented with this allele in AAP subjects. Individuals with Arg753Gln; Arg677Trp (GG; TC) combination showed an elevated risk of AAA (OR=1. 6, 95% CI: 0. 5-4. 2, p> 0. 05). Conclusion: Arg677Trp polymorphism of TLR-2 rendered a higher risk for the de-velopment of abscesses in apical periodontitis. It is recommended to explore role of this polymorphism in other populations.

Statement of the Problem: Oral lichen planus is a common mucocutaneous lesion with a chronic inflammatory process mediated by immune factors while a few cases of the disease become malignant. Purpose: This study aimed to determine the frequency of p53 marker as a tumor suppressor in patients with erosive and non-erosive oral lichen planus (OLP) by using immunohistochemical methods. Materials and Method: This descriptive cross-sectional study investigated the p53 expression in 16 erosive OLP, 16 non-erosive OLP samples, and 8 samples of normal oral mucosa through immunohistochemistry. The percentage of stained cells in basal and suprabasal layers, and inflammatory infiltrate were graded according to the degree of staining; if 0%, <10%, 10-25%, and >50% of the cells were stained, they were considered as (-), (+), (++), (+++) and (++++), respectively. The obtained data was statistically analyzed and compared by using Chi square and Fisher’ s exact test. Results: The mean percentage of p53 positive cells in erosive OLP (34. 5± 14. 2) was considerably higher than that in non-erosive OLP (23. 8± 10. 4) and normal mucosa (17. 5± 17). There was a significant difference among the three groups of erosive, nonerosive and control in terms of staining intensity. No significant difference existed between the patients’ age and sex in the two OLP groups. Conclusion: The increased incidence of p53 from normal mucosa to erosive OLP indicated the difference between biological behavior of erosive and non-erosive OLP. It can be claimed that the erosive OLP has great premalignant potential compared with the non-erosive one.

Statement of the Problem: One major goal of tissue engineering and regenerative medicine is to find an appropriate source of mesenchymal stem cells (MSCs) with higher differentiation ability. Purpose: In this experimental study, the osteogenic and chondrogenic differentiation ability of buccal fat pad derived MSCs (BFP-MSCs) with gingival derived cells (GDCs) were compared. Materials and Method: BFP-MSCs and GDCs were cultured enzymatically and expanded. The expanded cells were analyzed for membrane-associated markers, using flow cytometry. Then the ability of these cells to differentiate into osteocyte and chondrocyte was assessed morphologically and by mRNA expression of collagen I (COLL), BGLA and bone morphogenetic protein 2 (BMP2) using qRT-PCR. Results: Flow cytometry analysis showed that both BFP-MSCs and GDCs expressed the characteristic stem cell markers such as CD73, CD44, and CD90, whereas they did not express hematopoietic markers. Mineralized calcium deposition was observed apparently in BFP-MSCs cultured in osteogenic medium but GDCs showed fewer mineralized nodules. The mRNA expression levels of BGLA and BMP2 showed 7×105 and 733-fold more mRNA expression in BFP-MSCs treated with differentiation media compared to the control group. In chondrogenic differentiation, BFP-MSCs transformed from a spindle to a cuboidal shape while GDCs showed only a slight transformation. In addition, mRNA expression of COLL showed 282-fold higher expression in BFP-MSCs in comparison to the control group. Such significant difference in mRNA expression of BGLA, BMP2, and COLL was not observed in GDCs compared to their corresponding controls. Conclusion: Based on the present results, BFP yields a greater proportion of stem cells compared to gingiva. Therefore, this tissue can be introduced as an easily available source for the treatment of periodontal defects and other maxillofacial injuries.

Statement of the Problem: Pemphigus vulgaris is characterized by intraepithelial vesicles, but pathogenesis of vesicle formation in this disease has not been substantiated yet. Purpose: The present study investigate extrinsic apoptotic pathway in oral pemphigus vulgaris using TUNEL and important immunohistochemical markers of extrinsic pathway, TNFR1 and FasL. Materials and Method: In the present cross sectional study, 25 oral pemphigus vulgaris samples and 6 normal oral mucosa were analyzed for the presence of apoptosis by TUNEL and the staining of TNFR1 and FasL in basal and parabasal layers around vesicle, vesicle floor, vesicle roof and acantholytic cells. The staining expression and intensity were measured and the obtained data were analyzed by Wilcoxon and Mann-Whitney tests. Results: There was no or faint staining of TUNEL, FasL and TNFR1 in normal oral mucosa. In addition, there was no significant difference between the staining of TUNEL technique in different layers. The staining of TNFR1 marker was very high in all regions. FasL marker was not positive in the basal and parabasal layers around vesicle in 92% of samples but showed a varied and different staining in vesicle region. There was a significant difference between the each two markers in all layers ( p <0. 001). Conclusion: Apoptosis is probably is a preceding phenomenon to acantholysis in pemphigus vulgaris. It appears that the apoptosis occurs mostly by extrinsic pathway using proapototic mediators TNFR1 and FasL.

Statement of the Problem: Temporomandibular joint disorders (TMD) may show a poor correlation between their clinical findings and radiological characteristics. Purpose: The aim of this study was to assess the osseous alterations of temporoman-dibular joint (TMJ) in symptomatic and asymptomatic subjects by employing cone beam computed tomography (CBCT) images. Materials and Method: In this study, CBCT images of 120 temporomandibular joints in 30 patients with TMJ disorder and 30 age-and sex-matched individuals without TMJ complaints were evaluated. Osteoarticular derangements of the joint were as-sessed by two experienced examiners. Data was statistically analyzed with SPSS soft-ware using chi-square test (p <0. 05). Results: Out of 120 CBCT images (60 in each group), at least one osseous change was observed in 90% and 86. 7% joints in symptomatic and asymptomatic subjects, respec-tively. There were no significant differences between symptomatic and asymptomatic subjects regarding frequency of osteoarticular changes including flattening (73. 3% vs. 75%), irregularity (36. 7% vs. 48. 3%), sclerosis (20% vs. 8. 3%), cyst (3. 3% vs. 3. 3%), erosion (13. 3% vs. 21. 7%), hypoplasia (3. 3% vs. 5%), ankylosis (1. 7% vs. Zero), oste-ophyte (43. 3% vs. 40%), decrease joint space (3. 3% vs. 3. 3%), and increase joint space (5% vs. 5%). (p> 0. 05) Conclusion: By employing CBCT as a modern diagnostic imaging tool, findings of this study revealed that the frequency of various temporomandibular joint alterations on CBCT images is comparable in patients with and without TMD complaints, sug-gesting that some people with TMJ structural damage may not display clinical manifes-tations. Moreover, CBCT imaging might not be necessary for TMD patients and more attention should be given to clinical examination.

Statement of the Problem: Macrophages are the target of attention in numerous diseases. Many studies reported them as the regulators of the growth, dissemination, and clinical behavior of various lesions. There are relatively scarce data regarding the role of macrophages in oral lesions, particularly odontogenic lesions. Purpose: This study investigated the macrophage density in odontogenic lesions of diverse biologic performance. Materials and Method: In this comparative analytical study, 60 cases of odontogenic lesions including ameloblastoma, keratocystic odontogenic tumor, dentigerous cyst, and radicular cyst were immunohistochemically stained with anti-CD68 antibody. Oneway ANOVA and Tukey's HSD test were used for statistical analysis. Results: The results showed that the macrophage density in keratocystic odontogenic tumor (35. 72± 7. 74) and ameloblastoma (46. 12± 9. 84) was not significantly different from that in dentigerous cyst (43. 87± 8. 13). Interestingly, the macrophage density in keratocystic odontogenic tumor was lower than that in dentigerous cyst. No significant difference was observed in macrophage density between the ameloblastoma and much less aggressive lesions like dentigerous cyst (p= 0. 59). Macrophage density in radicular cyst (81. 53± 11. 04) was significantly higher than other odontogenic lesions (p< 0. 001). Conclusion: The lack of significant differences in macrophage density between the known aggressive odontogenic tumors and much less aggressive lesions implied that macrophages might not contribute to the biological behavior of the odontogenic lesions. Therefore, it could support the notion that targeted therapy would not have prominent clinical potential to decrease the extent of mutilating surgeries in odontogenic lesions.

Statement of the Problem: In dentistry, incorrect working posture is the most important cause of musculoskeletal disorders. Purpose: The aim of this research was to evaluate the work postures of general dentists and specialists using rapid entire body assessment (REBA) method. Materials and Method: In this cross-sectional study, work postures were assessed in 90 dentists by employing REBA method. Stratified sampling method was used. Data were analyzed by analysis of variance (ANOVA), Independent t-test and Pearson’ s correlation test in SPSS 19. Results: The results showed that work postures of 90% of dentists were at moderate-to high-risk levels. Among the specialists, periodontists, pedodontists and oral and maxillofacial surgeons had the worst body postures. Conclusion: In general, dentists’ working postures need improvement and consequently, a more comprehensive ergonomic training and promotion is required in dentistry curriculum at Universities.

Immune thrombocytopenic purpura (ITP) is an immune-mediated acquired disease found in both adults and children. It is characterized by transient or persistent decreases in the platelet count. We report a case of ITP detected based on oral hemorrhagic symptoms. The patient was a 79-year-old female with no significant past medical history. She presented with sudden onset of gingival bleeding and hemorrhagic bullae on the buccal mucosa. Gingival bleeding was difficult to control. Laboratory tests revealed severe thrombocytopenia with a platelet count as low as 2000/μ L. Under a provisional diagnosis of a hematological disorder, she was referred to a hematologist. A peripheral smear showed normal-sized platelets. A bone marrow examination revealed increased numbers of megakaryocytes without morphologic abnormalities. The patient was diagnosed with ITP and treated with a combination of pulsed steroid therapy and high-dose immunoglobulin therapy. However, her severe thrombocytopenia was refractory to these treatments. Then, a thrombopoietin receptor agonist was begun as a second-line treatment. Her platelets rapidly increased, and no bleeding complications were reported. Because oral symptoms can be one of the initial manifestations of ITP, dentists should be familiar with the clinical appearance of ITP, and attention must be paid to detect and diagnose unidentified cases.

Solitary myofibroma is an uncommon benign soft tissue neoplasm of myofibroblastic origin exhibiting head and neck region predilection but its presence in the jaws is rare. Myofibroma presents as painless mass and may demonstrate rapid enlargement and growth that clinically mimic malignancies. This report presents a 4-year-old male pa-tient with a rapidly growing mandibular gingival mass with some evidence of underly-ing alveolar bone destruction. Incisional biopsy was performed and the specimen was stained with hematoxylin and eosin and immunohistochemical antibodies for α SMA, CD34, S100 and desmin. The diagnosis of myofibroma was made and the lesion was completely excised. The knowledge about microscopic features of this rare neoplasm helps to have a proper diagnosis and avoid unnecessary treatment.