Journal of Dental Medicine

Normal 0 false false false EN-US X-NONE AR-SA In order to evaluate the effect of chlorhexidine mouthwash in controlling oral complications of chemotherapy, 146 patients were recruited among the patients referred to heamatology department of Shariati hospital who were under treatment by routine chemotherapic drugs like EBDV, CMF or FU-Lucoverin5 for first, second or third time. The patients were  allocated into two groups to receive either chlorhexidine or Placebo  for a week after careful examination and evaluation. Finally, It was concluded that Chlorhexidine is effective to reduce oral complications of chemotherapy (P-value≤0.002).

Background and Aim: Oral lichen planus is a chronic mucocutaneous disease with various clinical expressions. The histopathologic features are not characteristic and may be seen in other diseases. The aim of this study was to determine the clinical and pathologic features of oral lichen planus in oral pathology department of dental school, Tehran university of medical sciences.

Materials and Methods: In this case series study, archive of oral pathology department from 1968 to 2002 was reviewed and cases diagnosed as lichen planus and related lesions selected. The diagnosis of oral lichen planus was confirmed by evaluation of microscopic slides. Clinical informations such as age, sex, site and duration of lesions and differential diagnosis as well as microscopic findings were recorded. Data were analyzed with SPSS software using t student, ANOVA, Chi-square and Post Hoc Tukey tests with p<0.05 as the limit of significance.

Results: From a total of 402 cases recorded as lichen planus and related lesions, 251 cases were confirmed for final analysis. The mean age of patients was 42 years (5 to 83 years). 50.4% of cases were men and 49.6% women. The most prevalent clinical type was the ulcerative form and the mean duration of disease was 18.4 months. Buccal mucosa was most frequently involved followed by the tongue and gingiva. A white patch, Wickham’s striae and mucosal erythema were the most prevalent clinical appearance and parakeratosis , orthokeratosis and eosinophilic band the most frequent microscopic features.

Conclusion: Based on the results of this study, the correlation of clinical and pathological findings in the proper diagnosis of oral lichen planus is emphasized.

Background and Aim: The cell cycle is an important event in tumor growth and differentiation and several molecules are involved in this process. The aim of this study was to evaluate the expression of cyclin D1 (a cell cycle inducer) and p21 (a cell cycle inhibitor) in ameloblastoma of the jaws.

Materials and Methods: In this cross-sectional study, 40 cases of ameloblastoma were selected from the archive of oral pathology department. 3 micron sections were cut from paraffin blocks and immunohistochemically stained with antibody against cyclin D1 and p21waf. Stained cells were counted using an eyepiece graticule and labeling index was calculated. Data were analyzed by SPSS version 11.5 for windows using Mann-Whitney and Wilcoxon signed ranked tests with p<0.05 as the level of significance.

Results: Expression of cyclin D1 protein was detected in nuclei of many tumoral cells. The expression of cyclin D1 in solid and unicystic ameloblastoma and also between its follicular and plexiform variants was not statistically different (P>0.05). There was no statistically significant difference in expression of cyclin D1 between peripheral and central cells (P>0.05). Expression of p21 protein was detected in nuclei of some tumoral cells. There were no statistically significant differences between p21 expression in unicystic and solid ameloblastoma (P>0.05). P21 expression was statistically different between plexiform and follicular variants of ameloblastoma (P=0.049). The difference between p21 expression in peripheral cells of plexiform and follicular variants was statistically significant (P=0.009). This was not observed in central cells. There was no statistically significant relation between p21 and cyclin D1 expression in ameloblastoma (P>0.05).

Conclusion: Based on the results of this study, cyclin D1 expression in ameloblastoma is in high level and it could have an important role in the process of tumorigenesis. P21 expression in ameloblastoma is very faint and its possible effects need further investigation.

Background and Aim: Among different treatments of patients with Class III malocclusion , orthopedic protraction of maxilla has been known as an effective method in mixed dentition period. The aim of this study was to evaluate the cephalometric changes of Cl III patients in mixed dentition period following face mask therapy and slow maxillary expansion.

Materials and Methods: This was a before-after study which was conducted on 10 children in mixed dentition period, who had class III malocclusion and maxillary deficiency according to the Stiener and Mc Namara's analysis. The patients were all treated by protraction face mask and slow maxillary expansion. The cephalometric changes of maxilla , mandible and dental relations during the treatment were analyzed by Paired sample T Test. P<0.05 was considered as the level of significant.

Results: The overjet increasement was 1.7mm. Co. ANS distance improvement was 5.6mm, Ptm.ANS distance increasing was 3mm, and ultimately improvement of Gf.s distance was 1.5mm which were all statistically significant (p<0.05).

Conclusion: Based on the results of this study, face mask therapy with slow maxillary expansion is able to improve the horizotal position of maxilla, in patients with Cl III malocclusion , in mixed dentition period.

Background and Aim: The aim of this investigation was to evaluate the osteopromotion property of homogenous demineralized dentin matrix (HDDM) on experimental surgical bone defects in parietal bone of rabbits using the guided bone regeneration (G.B.R.) technique incorporating Paroguide collagen membrane.

Materials and Methods: Surgical bone defects were created in 6 Newzland white rabbits (2 defects in each rabbit). The defects were protected by Paroguide membrane alone (control group) or filled with HDDM and protected by Paroguide membrane (experimental group). The HDDM had been obtained from the central incisors of rabbits. The rabbits were sacrificed after 15, 30, 45, 60, 75 and 90 days and the defects examined histologically. Data were analyzed using pair-t test. The level of significance was set at p=0.03.

Results: Histologically, the volume of newly formed bone matrix was significantly greater in the experimental group. No inflammatory reaction was seen in either experimental or control groups.

Conclusion: Bone regeneration was accelerated in the bone defects filled with HDDM in comparison to the control group.

Background and Aims: One of the common human evolutionary anomalies is dental Missing. Evolution of dental system is toward deduction of teeth number. The Missing of third molar is interesting subject for dentists and genetic researches because of its variety in different races. Consideration of bilateral effect of third molar Missing with jaw relation is an important subject. The aim of this study was to evaluate the third molar missing in Cl I and Cl II skeletal (without rotation) and comparison of them together.

Materials and Methods: The patients of the orthodontic department of school of Dentistry (Tehran University of Medical Sciences) were analyzed. About 121 patients had Cl I and 60 patients had ClI jaw relation. This relation identified based on cephalometric lateral radiographic ANB corner angle. Patient who had rotation in maxilla or mandible based on SN-Go Gn angle were excluded. The incidence of third molars agenesis in individual dentition quadrants, upper and lower jaw and right and left side of dentition was examined from panoramic radiography. AChi-square test was used for statistical analysis of data.

Results: Missing of one or more third molar in skeletal Cl I and Cl II was 43% and 33.3%, respectively. Missing of one or more third molar in Cl II was fewer than Cl I, but no statistically significant differences were seen between them.

Conclusion: There was not a direct relationship between jaw relation and third molar Missing.

Background and Aims: The main purpose of orthodontic treatment is normal positioning of teeth in three dimensional plans, including the mesiodistal inclination. In this study, mesiodistal axial inclination of posterior teeth in skeletal class II was evaluated and compared with that of posterior teeth in skeletal class I.

Materials and Methods: Seventy-eight panoramic radiographs for subjects between 12 to 24 years old with skeletal class I and 78 panoramic radiographs for subjects between 12 to 19 years old with skeletal class II were selected. All of the subjects were in permanent dentition with no tooth missing, no tooth extraction, no impacted tooth, and no crowding in posterior teeth. Two reference lines were established over each radiograph: the upper one passing through the most inferior point of right and left orbits lower one passing through the right and left mental foramina. After that, the long axis of teeth was traced (the image of root canal in single-rooted teeth, mean image of buccal and palatal canals in upper premolars, mean image of mesial and distal canals in lower molars, and the image of palatal canal in upper molars.). The mean values for two skelotodental classes were analyzed using T-test.

Results: The results showed that there was significant difference between (P<0.05) mesiodistal axial inclination of teeth 15, 16, 17, 25, 26, and 27 in upper jaw in skeletal class II compared with that of the same teeth in skeletal class I, which was more mesially in skeletal class II. Mesiodistal axial inclination of teeth 36, 46, and 47 in lower jaw was more mesially in class II compared with that of the same teeth in class I. For other teeth there were no significant differences between two skeletodental classes (P>0.05).

Conclusion: The mesiodistal axial inclination of upper molars and second premolars and lower molars in class II was more mesially compared with that of the same teeth in class I.

Background and Aims: Nowadays, calcium hydroxide is used as a dressing for canal sterilization and repair progression of apical lesions. The aim of this study was to investigate the effect of calcium hydroxide as an intracanal medicament on the apical microleakage of root filling.
Materials and Methods: In this experimental study, 46 extracted single-rooted human teeth were instrumented with step-back technique to master apical file (MAF) size 35. Specimens were randomly divided into 2 groups (n = 20). In group 1, the specimens were treated with calcium hydroxide intracanal medication and in group 2, the samples did not receive any medication. The teeth were incubated in 100% humidity at 37°C for one week. After that, calcium hydroxide was removed using irrigation with normal saline and reaming with MAF. The root canals were obturated with gutta- percha and AH26 sealer using lateral compaction technique. Specimens were incubated in 100% humility at 37°C for 72 hours and then immersed in India ink for 1 week. Finally, the teeth were cleared and the maximum linear dye penetration was measured under a stereomicroscope at 4X magnification. The data were analyzed by T-test and Chi-square.
Results: There was no significant difference between the two experimental groups (P=0.068).
Conclusion: The findings of this study indicated that using calcium hydroxide as an intracanal medicament did not influence the apical microleakage after final obturation of the root canal system.

Background and Aims: Reliable bonding between tooth substrate and zirconia-based ceramic restorations is always of great importance. The laser might be useful for treatment of ceramic surfaces. The aim of the present study was to investigate the effect of laser irradiation on the shear bond strength of zirconia ceramic surface to dentin.

Materials and Methods: In this experimental in vitro study, 40 Cercon zirconia ceramic blocks were fabricated. The surface treatment was performed using sandblasting with 50-micrometer Al2O3, CO₂ laser, or Nd:YAG laser in each test groups. After that, the specimens were cemented to human dentin with resin cement. The shear bond strength of ceramics to dentin was determined and failure mode of each specimen was analyzed by stereo-microscope and SEM investigations. The data were statistically analyzed by one-way analysis of variance and Tukey multiple comparisons. The surface morphology of one specimen from each group was investigated under SEM.

Results: The mean shear bond strength of zirconia ceramic to dentin was 7.79±3.03, 9.85±4.69, 14.92±4.48 MPa for CO₂ irradiated, Nd:YAG irradiated, and sandblasted specimens, respectively. Significant differences were noted between CO₂ (P=0.001) and Nd:YAG laser (P=0.017) irradiated specimens with sandblasted specimens. No significant differences were observed between two laser methods (P=0.47). The mode of bond failure was predominantly adhesive in test groups (CO₂ irradiated specimens: 75%, Nd:YAG irradiated: 66.7%, and sandblasting: 41.7%).

Conclusion: Under the limitations of the present study, surface treatment of zirconia ceramics using CO₂ and Nd:YAG lasers was not able to produce adequate bond strength with dentin surfaces in comparison to sandblasting technique. Therefore, the use of lasers with the mentioned parameters may not be recommended for the surface treatment of Cercon ceramics.

Background and Aims: The aim of this study was to measure the degree of conversion (DC) of three types of composite resins (micro-hybrid, nano-hybrid and Ormocer) with different light curing units (LED LCU and QTH LCU) in two depths.

Materials and Methods: Three commercially available dental resin composites were used in this study: (Tetric Ceram, Ivoclar Vivadent, Liechtenstein-A2 shade), (Tetric Evoceram, Ivoclar Vivadent, Liechtenstein-A2 shade), (Ceram X, Dentsply, Germany-M₂ shade). Specimens were divided into two groups, 5 specimens were photo-activated by QTH unit (Coltolux 75-Colten) and the other five specimens were cured by LED (Demi-Kerr). Then each specimen was sectioned at the top surface and at 2-mm depth. The DC was measured by FT-IR
(Bruker-tensor 27). The data were analyzed by 3-way ANOVA test.

Results: There was significant difference between tested composite resins (P<0.001). The results of top surfaces were significantly different from those observed at 2-mm depth (P<0.001). The type of curing unit affected the polymerization of Ceram X resin composite.

Conclusion: This study showed a significant difference in the degree of conversion in different thicknesses within three groups of resin composites.

Background and Aims: The vitality pulp tests are necessary for diagnosis of pulpal disease and differentiation between endodontic and non-endodontic diseases. Thermal and electrical tests are conventional methods for evaluation of pulp vitality. The purpose of this study was to evaluate the effect of thermal changes on the tooth response to the electric pulp tester.

Materials and Methods: In this study, 160 intact maxillary central incisors of 40 voluntaries were evaluated. After isolation, electric pulpal response threshold in patients were recorded. After heat and cold tests, the electrical pulp test was repeated. The degree of response was recorded. The data were analyzed using pair T-test and independent T-test.

Results: The result of this study demonstrated that the average of teeth response to the electric pulp tester before and after cold test was 1.3 and 1.7, respectively. The average was 1.4 and 1.7 before and after heat test, respectively. There was no significant difference (P<0.001) between the pulpal response before and after thermal tests (heat and cold tests). In addition, no significant difference was found between pulpal response after heat and cold tests (P=0.25).

Conclusion: The response of tooth to the electric pulp tester was influenced by heat and cold tests.

  Background and Aims: Dental implants have been studied for replacement of missing teeth for many years. Productivity of implants is extremely related to the stability and resistance under applied loads and the minimum stress in jaw bone. The purpose of this study was to study numerically the 3D model of implant under thermal loads.

  Materials and Methods: Bone and the ITI implant were modeled in “Solidworks” software. To obtain the exact model, the bone was assumed as a linear orthotropic material. The implant system, including implant, abutment, framework and crown were modeled and located in the bone. After importing the model in Abaqus software, the material properties and boundary conditions and loads were applied and after meshing, the model was analyzed. In this analysis, the loads were applied in two steps. In the first step, the mechanical load was applied as tightening torque to the abutment and the abutment was tightened in the implant with 35 N.cm torque. In the second step, the thermal load originated from drinking cold and hot water was applied as thermal flux on the ceramic crown surface in this model.

  Results: Thermal analysis results showed that the thermal gradient in the bone was about 5.5 and 4.9 degrees of centigrade in the case of drinking cold and hot water respectively , although the maximum gradient of the whole system was reduced to 14 degrees, which occurred, in the crown by drinking cold water.

  Conclusion Thermal stresses were so small and it was because of the low thermal gradient. Maximum stresses occurred in the abutment were due to the tension preloads which were originated from the tightening torque.

Background and Aims: Type 1 diabetes mellitus, is the most common metabolic disorders in children and adolescents. The aim of this study was to assess the state of oral health in children with type 1 diabetes compared with healthy children in 2013-2014 in Hamadan province, Iran.

Materials and Methods: The specimens were selected through convenience sampling in two groups. Group one consisted of 80 individuals (5-18 years old; case group), suffering from type 1 diabetes mellitus referred to the Pediatric endocrine clinic. Control group consisted of 80 non-diabetic healthy children who were out- patients of pediatric and orthodontic department of Hamadan dental school. Two groups were similar in age and sex. The data were collected through a questionnaire, medical records and clinical examination. DMFT, dmft, GI and PI indices were assessed in each patient. Data were analyzed using ANOVA and T-test.

Results: In spite of similarity in oral hygiene habits in both group, there was no significant difference in mean DMFT and permanent decayed teeth in both groups (P>0.05), but the mean dmft (P<0.008) and primary decayed teeth (P<0.011) in the control group was significantly higher than that of the case group. Also, diabetic patients had significantly more gingival inflammation (P<0.05). The mean PI in the two groups did not differ significantly. Oral hygiene habits were similar in both groups but diabetic patients were significantly referred to dentists with lower frequency then that of control group (P=0.00).

Conclusion: The devastating effects of diabetes on the oral health, along with other side effects can be effective in promoting tooth decay and gingivitis in diabetic patients. Unfortunately, oral health care and programmed dental visit were not the priority for the diabetic patient (and parents) involved in our study. Therefore, programs to increase awareness and encourage patients for a better control of their oral health in order to diminish diabetes' devastating effects is recommended.