Journal of Dental Medicine
Year:2019 | Volume:32 | Issue:1 |Papers Count:14

Background and Aims: The aim of this study was to assess the outcome of short implants (<8 mm length) as an alternative to sinus lift surgery and placement of standard-length implants (10-12 mm length) for rehabilitation of atrophic posterior maxilla. Materials and Methods: In this prospective clinical trial, 26 patients with 6-7 mm of residual alveolar bone height in their atrophic posterior maxilla were randomly divided into two groups (n=13). The test group received short implants without sinus lift surgery while the control group received standard-length implants after maxillary sinus floor augmentation. The bone loss was evaluated at 1 to 2 years after loading of implants on radiographies and the comparison between the two groups was done using chi-square test. Results: At 1 year, two patients (15. 4%) in the short implant and one patient (7. 7%) in the standard implant group experienced bone loss (P=0. 5). At 2 years, four patients (30. 8%) in the short implant and two patients (15. 4%) in the standard implant group showed bone loss (P=0. 4). Conclusion: At 2 years after loading, the bone loss was not significantly different around short and standard-length implants. Short implants appeared to be a suitable alternative to sinus lift surgery and placement of standard-length implants for rehabilitation of atrophic posterior maxilla. However, further studies with longer follow ups are still required to cast a final judgment in this respect.

Background and Aims: Candida is an opportunistic pathogen that causes illness in people with a defective or weakened condition. Infectious diseases (periodontal diseases) are inflammatory and malignant inflammation of the dental-gum complex, in which the growth of biofilms caused by Candida glabrata, Parapseilosis and Tropikalis is less than Candida albicans. Brown algae Sargasum is more compatible with human medicines due to having a natural origin than chemical drugs and has less side effects. The aim of the present study was to investigate the molecular characteristics of Candida species isolated from periodontal infections and the effect of Sargassum glaucescens extract on biofilm gene expression using Real-Time-PCR. Materials and Methods: Oral samples of periodontal infection were collected from the referred patients. To isolate the candidate species, the specimens were cultured on a Sabouraud dextrose agar containing chloramphenicol (SDAc). The extracted DNA was extracted from colonies grown from Kit and Glass pearl. Grown chickens were identified by specific primers by PCR-RFLP method. In order to detect the expression of ALS genes in Candida isolates, RNA extraction was performed using Phenol-Chloroform and Pearl glass, and the CLSI-M27-A2 method was used to evaluate the effect of Sargasum glaucescens extract of algae. Results: The results showed that the expression of ALS gene in periodontal infection is higher than other genes. Another role is ALS in the formation of Candida albicans biofilm. The minimum inhibitory concentration of fungal growth was 256 μ g/ml by algae extract. Sargasum glaucescens reduced the expression of ALS gene expression by about 62% in the sample. Conclusion: Sargasum glaucescens algae possesses specific pharmacological properties and antimicrobial and antimicrobial effects. The results of the study using Real Time PCR showed that expression of ALS gene in isolated studied with Sargasum algae extract was lower than untreated isolates. Thus, this indicated the positive role of treatment by sargasum glaucescens extract in reducing the expression of biofilm gene in isolates.

Background and Aims: Passive fitness of implant frameworks are important factors for long-term success of dental implant restorations. The aim of this in vitro study was to evaluate the dimensional changes of implant supported zirconia frameworks fabricated by Zirkonzahn CAD/CAM system during fabrication stages. Materials and Methods: The master model of 3-unit FDP was made of two implant abutments. The master model was scanned 12 times and data were saved as STL files (scanning groups). Using semi-sintered zirconia, 12 real-size frameworks (milling groups) and 12 enlarged frameworks which were then sintered (sintering group) were made in this system. Dimensions of master model and specimens of each stage were measured. The dimensional changes in respect to master model were calculated. Data were analyzed using Repeated measures ANOVA, independent t-test, and paired sample t-test at α =0. 05 of significance. Results: The milling stage showed greater dimensional changes comparing to the other stages (P<0. 05). At all stages, the dimensional changes of premolar abutment height were greater than canine (P<0. 001). Conclusion: Within the limitations of this study, the results suggested that the fabrication stages and size of abutments had significant effects on the dimensional changes of zirconia frameworks.

Background and Aims: Today, resin composites are one of the most commonly used materials in restorative dentistry. However, failure in resin treatments is also common due to its chemical nature and its high talent for decay recurrence. According to conservative approaches, "conservative" treatments are more likely to be considered than "Replacement" of damaged remedies. The purpose of this study was to compare different surface preparation methods on composite surfaces to achieve the highest bond strength between the old and new composites after accelerated aging. Materials and Methods: First, composite cylinders with a diameter of 6 and a height of 5 mm were prepared using an incremental technique and a microhybrid resin composite. The specimens were stored in distilled water for 6 months at 37° C and then the surfaces of all aged compsites were roughened using diamond milling followed by phosphoric acid etching. The specimens were randomly subjected into five groups. Group 1: GC Composite Primer. Group 2: Universal bonding containing silane (Kuraray). Group 3: Self etching adhesive (SE bond; Kuraray) Group 4: silane (Ivoclar Vivadent) + Second bottle of SE bond bonding system (Kuraray). Group 5: control group with no treatment. Then, 5 mm incremental of new composite (similar to the aged composite with different color) were placed on the surfaces of specimens, sectioned, and thermocycled for 3000 cycles for the microtensile bond strength evaluation. The specimens were evaluated using a stereomicroscope after failure. Data were analyzed by one-way ANOVA and Post Hoc Tukey test. Results: The specimens in which silane and SE bond were used showed the highest mean microtensile bond strength and those treated by universal bond showed the least bond strength which were significantly different (P=0. 02). All samples had cohesive failure patterns in all groups and the percentage of failures in old and new composites did not differ significantly (P=0. 69). Conclusion: : Based on the results, all surface preparations used in this study could provide an appropriate bond strength for repair of old composite restorations. Also, the microtensile bond strength between the old and new composites was higher than the cohesive strength of resin composite itself. However, the mean microtensile bond strength value for the group treated by universal bond was significantly lower than those treated by silane and hydrophobic containing bonding system.

Background and Aims: Despite patient’ s demand increased for tooth color restorations, the stable bond between dentin and composite is a challenge in dentistry. Dentin protease activation is responsible for dentin-resin bond failure. The aim of this study was to determine the best pretreatment agent to inhibit matrix metalloproteinase and increase resin-dentin bond durability. Materials and Methods: After collecting 24 intact third molars, the dentin surfaces were exposed immediately under DEJ. After acid etching of dentin rewetting was done with CHX 2%, EDC 0. 3 M for 60 and water (control group). Then the adhesive (Single bond, 3M ESPE, USA) and composite (Filtek Z250 XT, 3M ESPE, USA) were applied. 48 sectioned dentinal specimens were prepared. The specimens were divided into 3 groups. Each group was divided into 2 sub groups (n=8). In half of each group, the micro tensile bond strength test was done immediately and another part half 6 months. Then, the specimens were evaluated by stereomicroscope and SEM. Statistical analysis was performed using SPSS23 software, twoway ANOVA and multiple Tukey and T-test comparisons. P<0. 05 was considered as a significant level. Results: There were not significant differences between immediate micro tensile bond strength of CHX, EDC and control groups (P=0. 97). However, there was significant differences between CHX, EDC compared with the control group (P≤ 0. 0001). Comparison between the immediate and 6-month bond strengths in each group, only in EDC group, there was no significant after 6 months’ difference (P=0. 64). Conclusion: EDC and CHX t did not have any effect on the immediate microtensile bond strength. After 6 months, EDC prevented bond strength deterioration, but the bond strength was decreased after CHX usage.

Background and Aims: Removable partial denture (RPDs) is a common therapy for rehabilitation of partialy edentulous patients while RPD causes a lot of periodontal problems. The purpose of this study was to investigate the effect of RPDs made in Babol dental school on the periodontal health of abutment and non-abutment teeth. Materials and Methods: In this cross sectional study, 70 patients who were candidates for RPDs divided into four groups according to Kennedy classification. The following periodontal parameters were evaluated for abutment and non-abutment teeth, plaque index (PI), calculus index (CI), width of keratinized gingiva, bleeding on probing (BOP), periodontal pocket depth (PPD), tooth mobility (TM) and gingival recession. This clinical measurement was taken immediately before insertion of the RPD, then one, three, and six months later. These parameters were then analyzed using Mann-Whitney, Independent sample ttest, Covariance, Chi-square statistical tests. Results: In Class I; the mean score for the width of keratnized gingiva (P<0. 001), PPD (P=0. 002), and BOP (P<0. 001) of the abutment and non-abutment teeth were significantly different after 1 month. After 3 months there were significant differences with regard to the PI (P=0. 01), width of keratnized gingiva (P<0. 001), BOP (P<0. 001) and PPD (P<0. 001). After 6 months, only the PI, CI, and TM parameters were not statistically significant. In Class II; the mean score for width of keratnized gingiva (P<0. 001) and PI (P=0. 002) after 1 month, width of keratnized gingiva (P<0. 001), BOP (P=0. 02), PPD (P=0. 05) and TM (P=0. 03) after 3 months and width of keratnized gingiva (P<0. 001), PI (P=0. 04), BOP (P<0. 001) and TM (P=0. 03) after six months were statistically significant. In Class III; only gingival recession did not show any significant difference at 1 and 3 months later. The width of keratnized gingiva (P<0. 001), PI (P=0. 001), BOP (P<0. 001) and TM (P=0. 03) after 6 months were statistically significant. Conclusion: This study showed that RPDs affect the periodontal condition of both abutment and non-abutment teeth, which can be reduced by more precise design of the prosthesis, periodontal follow ups and good oral hygiene.

Background and Aims: The emergence of social web and impact on the communication of the individuals and the scientific activities of various communities has created serious research links among researchers. This issue that how Iranian researchers keep up to date themselves with new technologies and use them to engage in scientific issues has been a challenge that is constantly being addressed in the digital world. Therefore, the purpose of this study was to evaluate the scientific production of dentistry in Tehran University of Medical Sciences in the networks of ResearchGate and Mendeley using the Scopus citation database between 2015 and 2016. Materials and Methods: The study population included all scientific articles in the field of dentistry of Tehran University of Medical Sciences which were indexed in Scopus database between 2013-2016. The results were presented using descriptive statistics in the form of charts and tables. Results: In this study, it was determined that the scientific outputs of the researchers from Tehran University of Medical Sciences increased in 2015 and 2016. It was also found that the coverage of articles in the field of dentistry published by researchers at Tehran Medical Sciences Universities in the Scopus citation database in the mentioned years, were in a good position in both the Mendeley and ResearchGate networks. In addition, the number of references to the articles by researchers at Tehran University of Medical Sciences on the ResearchGate network in the field of dentistry was more than the Mendeley network. Conclusion: Based on the results of this study, it can be concluded that the performance of the researchers of the Tehran University of Medical Sciences in the field of oral and dental care and the extent of their coverage in the social networks of ResearchGate and Mendeley was high and desirable.

Background and Aims: Use of computer and internet in our modern and digitalized society is an efficient tool to be up to date and fulfil the information gaps. The aim of this study was to evaluate the extent of computer and internet usage among dental students of Islamic Azad University, Tehran, in 2016. Materials and Methods: This descriptive study for evaluating access and usage of computer and internet by dental students was done using a researcher-made questionnaire on 401 dental students. Validity and reliability (Kappa: 0. 82) of the questionnaire was confirmed. Statistical analysis was done by SPSS22 using descriptive and Logistic regression analyses. Results: More than 95% of the students had access to the computer and Internet. 45. 6% of students reported their skills were in the basic level. The major use of computer among the students was internet but only 13. 2% of students used Microsoft Office program. The students used the internet for dental subjects even monthly (34. 9%) or weekly (29. 4%). Only 9. 7% of the students had participated in educational workshop for learning methods of research. The most limitation was internet velocity. Positive correlation was found among prospering ownership status (P<0. 001), economic status (P=0. 05), level of education semester (P=0. 038) and the computer & internet usage (what’ s more in terms of access and also in terms of improve information and knowledge). Conclusion: Based on the results, a higher economic level, higher level of education, and property ownership made better access to the computer and Internet. However, computer skills should be more concerned in educational program.