JOURNAL OF DENTISTRY (SHIRAZ UNIVERSITY OF MEDICAL SCIENCES)
Year:2018 | Volume:19 | Issue:1|Papers Count:12

Statement of the Problem: Orthodontic appliances facilitate microbial plaque accumulation and increase the chance of white spot lesions. There is a need for new plaque control methods independent of patient's cooperation. Purpose: The aim of this study was to determine the effects of incorporating cop-per oxide (CuO) nanoparticles on antimicrobial properties and bond strength of orthodontic adhesive. Materials and Method: CuO nanoparticles were added to the composite trans-bond XT at concentrations of 0. 01, 0. 5 and 1 wt. %. To evaluate the antimicrobial properties of composites containing nanoparticles, the disk agar diffusion test was used. For this purpose, 10 discs from each concentration of nano-composites (total-ly 30 discs) and 10 discs from conventional composite (as the control group) were prepared. Then the diameter of streptococcus mutans growth inhibition around each disc was determined in blood agar medium. To evaluate the shear bond strength, with each concentration of nano-composites as well as the control group (conventional composite), 10 metal brackets were bonded to the human premolars and shear bond strength was determined using a universal testing machine. Results: Nano-composites in all three concentrations showed significant antimi-crobial effect compared to the control group (p< 0. 001). With increasing concen-tration of nanoparticles, antimicrobial effect showed an upward trend, although statistically was not significant. There was no significant difference between the shear bond strength of nano-composites compared to control group (p= 0. 695). Conclusion: Incorporating CuO nanoparticles into adhesive in all three studied concentrations added antimicrobial effects to the adhesive with no adverse effects on shear bond strength.

Statement of the Problem: Regional lymph nodes are the nodes draining lymph from region around the tumor and presence of metastatic tumor in regional lymph nodes is the most important prognostic factor for malignant tumors of epithelial origin. Lymphangiogenesis is associated with an increased incidence of regional lymph nodes metastasis and is possibly an essential step for metastasis. Tumor cells secrete lymphangiogenic cytokines, which results in formation of lymphatic vessels within and around the tumor and act as portals for tumor spread. Purpose: The present study aims to investigate and quantify lymphatic vessel density (LVD) in oral squamous cell carcinoma (OSCC) and determine whether LVD can predict the risk of sentinel lymph node metastasis. Material and Method: 50 specimens of OSCC, without and with lymph node metastasis (25 each) along with 25 specimens of normal oral mucosa were assessed and LVD was quantified by D2-40 immunostaining. Discrete hotspots of intra-tumoral lymphatics were identified in superficial and deep areas in all carcinomas to calculate LVD. Results: When compared to normal mucosa, LVD decreased in the superficial intratumoral areas and decreased further in deep areas. In addition, LVD in the superficial and deep areas of OSCC without nodal metastasis was significantly higher than that in OSCC with nodal metastasis. Conclusion: Our study provides evidence that lymphangiogenesis varies within the tumor. Lymphatic vessels are either compressed, collapsed, destroyed or absent in deep intratumoral region. Decrease in LVD predicts cervical lymph node metas-tasis both in superficial and deep areas. Lymphatics in superficial areas are proba-bly major conduit for nodal metastasis in OSCCs.

Statement of the Problem: It is crucial for clinicians to be certain about the location of mandibular canal and determine any anatomical variants relevant to it. The tem-poral crest canal (TCC) is a rare anatomical variant of mandibular canal that lack of awareness about its presence can complicate surgical procedures. Purpose: This study investigated the anatomical characteristics and prevalence of the TCC using CBCT. Materials and Method: This descriptive cross-section study evaluated 327 CBCTs (654 sides) from all the patients with various problems. TCC on sagittal and axial plans were identified and then classified into two types based on their configuration. The prevalence of TCC was calculated amongst men and women. Results: Six TCC (0. 91%) were observed in 654 sides. We observed all 6 TCCs in females. One case (0. 30%) was bilateral TCC, and the remaining four (1. 22%) cases were unilateral TCC (two on the left and two on the right side). Considering the clas-sification of TCC, five sides had presentation of type I and one case was type II based on Kawai et al. study. Conclusion: Three-dimensional images of CBCT data are useful in confirming the presence of TCC. TCC is considered as a clinically significant structure; therefore, this variation should be carefully investigated using reconstructed CBCT images.

Statement of the Problem: A great challenge in periodontal therapy is the regen-eration enhancement of osseous defects through applying osteoinductive materials. Demineralized freeze-dried bone allograft (DFDBA) has already been introduced as an allograft with osteoconductive and variable osteoinductive properties. Calci-um hydroxide [Ca(OH)2] is an available well-known material in dentistry, which induces hard tissue formation. Purpose: This study evaluated the efficiency of combination of DFDBA and Ca(OH)2 in improving the quality of osteoinduction of DFDBA. Materials and Method: Human bone marrow-derived mesenchymal stem cells were taken from volunteers’ iliac crest. Cell proliferation was determined by MTT test at 18, 24 and 48 hours post-culture in 10 groups. The employed material were 0. 5, 1. 0 mg/ml Ca(OH)2 in two forms of suspension and pH-adjusted solution, 10mg/ml DFDBA per se and in combination with 0. 5 and 1. 0 mg/ml Ca(OH)2. Mineralization was assessed by Alizarin red staining in 10 mg/ml DFDBA, DFDBA+ 0. 5 and 1 mg/ml Ca(OH)2 in solution and suspension forms. The data were statistically analyzed by using one-way ANOVA and Tukey’ s post-hoc test (p< 0. 05). Results: The pH-adjusted solutions exhibited better cell proliferation compared with the suspension groups. The combination of 0. 5mg/ml Ca(OH)2 solution and DFDBA increased the cell proliferation and mineralization compared with DFDBA per se (p= 0. 033). Conclusion: The combination of Ca(OH)2 with DFDBA improved the osteoinduc-tivity of DFDBA.

Statement of the Problem: Researchers always seek a new storage medium for avulsed teeth. Castor oil is a vegetable oil with several advantages such as antimicro-bial and antioxidant properties, low toxicity, and glutathione preservation capability, low cost, and high availability. Purpose: The purpose of this study was to evaluate and compare the capacity of castor oil as a new storage medium in preserving the viability of periodontal ligament (PDL) cells compared to Hank’ s balanced salt solution (HBSS) and milk. Materials and Method: Forty freshly extracted human teeth were divided into 3 experimental and 2 control groups. The experimental teeth were stored dry for 30 min and then immersed for 45 min in one of the following media; castor oil, HBSS, and milk. The positive and negative control groups were exposed to 0 min and 2 h of dry time respectively with no immersion in any storage medium. The teeth were then treated with dispase grade II and collagenase and the number of viable PDL cells were counted. Data were analyzed using Kruskal-Wallis test. Results: The percentage of viable cells treated with castor oil, HBSS and milk count-ed immediately after removal from these media were 46. 93, 51. 02 and 55. 10 % re-spectively. The statistical analysis revealed that the value for castor oil was signifi-cantly lower than HBSS and milk (p> 0. 05). Conclusion: Within the parameters of this study, it appears that castor oil cannot be served as an ideal medium for storage of avulsed tooth. More investigations under in vivo conditions are required to justify the results of this study.

Statement of the Problem: A significant proportion of patients undergoing chemo-therapy or radiotherapy suffer from mucositis. The first symptom of oral mucositis is pain. Severe pain, burning sensation, and discomfort in the oral cavity make it difficult to continue treatment and even continue living in these patients. Purpose: The aim of this study was to evaluate and compare the effect of amitriptyline mouthwash (in two forms of simple and niosomal) as a local anesthetic agent with benzydamine HCl mouthwash in oral mucositis after radiotherapy or chemotherapy. Materials and Method: This double-blind study was performed on 60 patients with oral mucositis caused by radiotherapy and chemotherapy. The severity of mucositis was determined based on patient judgment; then dental examination was performed and recorded in a checklist. Three groups were assigned based on using either benzy-damine HCL, amitriptyline, or niosomal form of amitriptyline. Pain and burning sensa-tion were evaluated with VAS at different time intervals: before use and one, five, ten, and thirty minutes and one hour after using mouthwash. T-test was used to compare the intensity of pain between the two groups. ANOVA and Tukey test were used to compare the intensity of pain between groups. Results: Statistical analyses showed the maximum reduction in pain intensity at two different time intervals (p= 0. 04). Ten minutes after the use of niosomal form of ami-triptyline, a 95% decrease in pain was observed. A 99% reduction in pain occurred after the use of simple form of amitriptyline (p= 0. 04). Conclusion: Use of amitriptyline mouthwash had local anesthetic effects in oral mu-cositis without systemic side effects. Decrease in the severity of pain with the use of amitriptyline mouthwash was more than that of benzydamine HCL mouthwash.

Statement of the Problem: Ignoring anatomic variations may lead to iatrogenic inju-ries by surgeons. Purpose: The aim of this study was to examine the relationship between the course of infraorbital canal and maxillary sinus using cone beam computed tomography scans (CBCT). Materials and Method: One hundred and ninety two CBCT scans were reviewed for 384 infraorbital canals. The anatomic variants of infraorbital canals were classified into three types based on the protrusion degree of the infraorbital nerve from the max-illary roof into the sinus. Measurements were made on infraorbital canal as vertical distance from the infraorbital rim to the infraorbital foramen, the maximum horizontal distance from the infraorbital canal to the canine root, the maximum diagonal length of the nerve protruded in sinus, the maximum vertical distance from the center of the nerve to the sinus roof. Results: 26. 5% of infraorbital canals were entirely contained within the sinus roof. 50. 3% of infraorbital canals were located below the roof but remaining juxtaposed to it. In 23. 2%, the nerve canal descended into the sinus. The prevalence of type3 of infraorbital canal significantly increased from 14. 8% in cases without an ipsilateral Haller cell to 29. 1% when a Haller cell was present. The average distance between the infraorbital foramen and the infraorbital rim were increased proportionally to the de-gree of protrusion of the nerve course into the maxillary sinus (ANOVA p< 0. 001). Conclusion: The infraorbital canal protrusion into the sinus is a common variation that must be considered during surgical procedures to avoid iatrogenic injury.

Statement of the Problem: The clinical success of ceramic depends on the quality of the bond between the zirconia and resin cement. Purpose: In the present study, the effects of universal and conventional MDP-containing primers were evaluated on the shear bond strength of zirconia ceramic and nanofilled composite resin. Materials and Method: Thirty blocks of zirconia ceramic (6mm×2mm) were pre-pared. Then the inner surfaces were air-abraded and divided into three groups (n= 10) as follows: untreated with primer (control group, I); All-Bond Universal (group II) and Z-Prime Plus (group III). The specimens in each group were bonded with Variolink N cement to cylinders of composite resin Z350XT. After 24 hour water storage, the shear bond strength test was performed with a universal testing machine at a crosshead speed of 1mm/ min and bond strength values (MPa) were calculated and analyzed with one-way ANOVA and post hoc Tukey tests (p< 0. 05). The failure mode of each specimen was evaluated under a stereomicroscope and representative specimens were analyzed by scanning electron microscopy (SEM). Results: The mean shear bond strength values (MPa) were 7. 58± 1. 62, 17. 51± 1. 34 and 22. 45± 3. 60 in groups I, II and III, respectively. These results indicated that the shear bond strength were significantly higher in groups II and III compared to the control group (p< 0. 001). Chemical pre-treatment of zirconia with Z-Prime Plus revealed significantly higher bond strength than the All-Bond Universal adhesive (p< 0. 002). All the failure modes were adhesive in the control group (I) and when using primer treatment, mixed failures occurred in 40% and 50% of specimens in groups II and III, respectively. Conclusion: Treatment with both primers resulted in higher bond strength values compared to the control group. The use of Z-Prime Plus treatment in combination with air-abrasion procedure resulted in the highest bond strength.

Statement of the Problem: Dental injection is one of the most fearful procedures in dental setting, especially for children. Many researchers have attempted to find a pain-less method. As computer controlled local anesthesia delivery system devices (CCLADs) allow the speed rate and pressure of injection solution to be controlled, they may cause less pain during injection in comparison to the conventional method. Purpose: The aim of this study was to compare pain perception in dental injection by Smartject with conventional technique. Materials and Method: The present study was a randomized single-blind crossover clinical trial. The participants consisted of 50 healthy volunteer dental students. They received a topical anesthetic agent plus injection in maxillary premolar buccal mucosa via conventional technique on one side (control) and a topical anesthetics agent plus injection in maxillary premolar buccal mucosa by Smartject on the other side (experimental). The first injection method was chosen based on block randomization table. A blind person recorded the subjects’ pain perception of injection based on the visual analogue scale (VAS) in the two groups. Repeated measure test, independent Student t-test and Student paired t-test were used. Statistical significance was defined at p< 0. 05. Results: There was statistically significant difference in VAS score between Smartject and the conventional technique. The mean of VAS scores for Smartject and the con-ventional technique were 14. 5± 7. 4 and 24± 12. 1, respectively. Conclusion: It is suggested, needle penetration is not the main reason of pain during injection. Inconsistent fluid pressure created by injected anesthetic solution on nerve fibers is more impressive in pain development. Hence, Smartject as a CCLAD can be considered as an appropriate device for dental injection.

Statement of the Problem: Histopathology is a gold standard diagnostic tool for oral lesions. Nonspecific and overlapping microscopic features often pose diagnostic chal-lenges in routine practice. In such conditions, deeper sections have utility to enhance the sensitivity and accuracy of the diagnosis. Purpose: To analyze the percentage of deeper sections requested and to evaluate the diagnostic efficacy of these deeper sections in routine oral histopathology practice. Additionally, the utility of deeper sections in specific oral lesions have also been eval-uated. Materials and Method: A total of 850 cases from the archives of Department of Oral Pathology and Microbiology, were analyzed, and 106 cases with deeper sections were selected. Out of 106, 82 cases were accepted for our analysis and 24 were rejected as deeper sections were done due to staining errors or folding of tissue. The present retro-spective study involves comparison of initial histological findings with those seen in deeper sections of same specimen. Results: Deeper sections improved the diagnosis of 48 cases (58. 54%). Remaining 31 cases (38%) showed the same histological features, whereas in 3 cases (3. 66%), initial sections were good as compared to deeper sections. Out of 22 cases of provisional hyperkeratotic/ dysplastic lesion, 16 (72. 72%) showed change in diagnosis, i. e. from mild to severe dysplasia or from dysplasia to carcinoma. A total 12 out of 17 (70. 59%) cases of odontogenic lesions were non-diagnostic or showed minimal characteristic features on initial sections, but their deeper sections revealed clearly identifiable fea-tures and some of them also showed cystic lesion turning into tumor pathology. Conclusion: This study highlights the diagnostic efficacy of deeper sections and their contribution towards providing accurate and more descriptive features.

Adenoid squamous cell carcinoma is a rare variant of squamous cell carcinoma with features of adenoid pattern. It has been reported to originate in the sun-exposed skin of the head and neck region. Although rare, there are cases documented within the oral cavity and nasopharynx. The clinical behaviour and the prognosis are variable. We report a case of adenoid squamous cell carcinoma in a 63-year-old female patient presented with a large mass in the left mandibular alveolar ridge. Histologically, the lesion showed areas of conventional squamous cell carcinoma along with atypical epithelial cells forming a glandular pattern. However, there is no evidence of glandular differentiation, secretory activity or its products. Adenoid squamous cell carcinoma must be differentiated from adenosquamous carcinoma in which adenocarcinoma elements are positive for mucins. There are few cases reported to establish biological behaviour and prognosis.

With the increasing number of young adults seeking orthodontic treatment to im-prove their smile esthetics or oral function, the time spent wearing brackets is one of the biggest challenges for these patients. Various surgical techniques have been developed over the years to accelerate tooth movement and reduce the total treat-ment time. A newly introduced, minimally invasive procedure namely piezopunc-ture, which uses a piezosurgical tool to create multiple cortical punctures through the gingiva, is presented in this report of two extraction cases.