Journal of Dental School
Volume:30 Issue: 3, 2012

Regeneration of large bone defects is a major challenge in maxillofacial reconstruction. The present study evaluated the efficacy of simultaneous use of demineralized bone matrix (DBM)، mesenchymal stem cells (MSCs) and platelet rich in growth factors (PRGF).

Stem cells were isolated from the femoral bone marrow of rabbits and their stem cell nature was confirmed. PRGF was prepared by drawing 5 cc of blood from the heart of rabbits and its centrifugation. A total of four 8mm defects were surgically created in rabbits calvaria using a trephine bur. Third passage cells were loaded on DBM and stored in an incubator for 24 hours. DBM، DBM+PRGF، DBM+MSCs and DBM+PRGF+MSCs were used in groups 1، 2، 3، and 4، respectively. At 6 and 12 weeks rabbits were sacrificed using vital perfusion. Histomorphometric analysis was performed on 5 µm sections stained with Hematoxylin and Eosin (H &E). Data were analyzed using SPSS version 14 software and ANOVA test.

Histomorphometric analysis of the sections at 6 and 12 weeks post-operation demonstrated 74. 6% and 20. 31% osteogenesis in group 1، 14. 35% and 28. 44% in group 2، 17. 75% and 31. 33% in group 3 and 18. 94% and 37. 21% in group 4، respectively. Percentage of new bone formation was higher in group 4. However، this difference was not statistically significant (P>0. 05).

It seems that simultaneous use of DBM، PRGF and MSCs results in increased bone regeneration in 8 mm rabbit calvarial bone defects when compared to the application of MSCs or PRGF alone.

By the advancements in root canal filling systems، a new sealer namely Epiphany self-etch sealer (Pentron Clinical Technologies، LLC، Wallingford، CT، USA) was recently introduced to the market that does not require self-etching primer application prior to the use of sealer. On the other hand، dentin surface conditioning with various irrigation solutions can cause chemical and structural dentinal changes. The present study sought to assess the effect of EDTA (final irrigation with distilled water or chlorhexidine) and MTAD on coronal microleakage in root canals filled with Resilon/Epiphany self-etch or AH Plus/Gutta Percha obturation materials.

In this ex-vivo study، a total of 140 extracted single rooted human teeth were selected and irrigated with 1. 3% sodium hypochlorite during preparation. Samples were divided into 6 test groups and 2 positive and negative control groups. Smear layer was removed by EDTA and final irrigation with distilled water in groups 1 and 4، by EDTA and final irrigation with 2% chlorhexidine in groups 2 and 5 and by MTAD in groups 3 and 6. In groups 1، 2 and 3 canals were filled with AH Plus sealer and Gutta Percha while in groups 4، 5 and 6 canals were filled with Resilon and Epiphany self-etch sealer using lateral condensation method. After placing samples in a split-chamber and sterilizing them، the coronal part of teeth was contaminated with human saliva. Samples were controlled daily for 60 days. Chi square test، survival analysis and log-rank test were used for data analysis.

Nine samples (45%) in group 1، 14 samples (70%) in group 2، 18 samples (90%) in group 3، 13 samples (65%) in group 4، 7 samples (35%) in group 5 and 13 samples (65%) in group 6 had microleakage after 60 days. Difference in resistance against microleakage between groups 1 and 3 and also 3 and 5 was statistically significant.

MTAD does not have a negative impact on sealing properties of Resilon/Epiphany self-etch sealer but EDTA can be an appropriate dentin conditioner before using AH Plus sealer and Gutta Percha. Also، Chlorhexidine can be a good final irrigant in root canals that are going to be filled with Epiphany self-etch sealer/Resilon.

Microbial plaque is the main cause of periodontal disease. Production of free oxygen radicals is an immune system mechanism to destroy invading microorganisms which per se results in further destruction of periodontal tissues. The present study sought to assess the efficacy of anti-oxidant application (vitamin E) as an adjuvant treatment following scaling and root planning in periodontal patients. For this randomized clinical trial 10 patients aged 30 to 50 years suffering from moderate to severe periodontitis with no systemic disease were selected. After scaling and root planning، 5% vitamin E for one side and placebo for the opposite side were poured in a maxillary custom tray and placed inside the mouth. Type of treatment did not have a significant effect on the understudy factors. However، time had a significant effect on the majority of indices. Healing was significantly better at week 4 following initiation of treatment compared to week 2. The values in proximal and radicular sites were -0. 151، p=0. 002 and -0. 31، p=0. 001 for pocket depth، -0. 217، p=0. 002 and -0. 401، p=0. 001 for CAL، -4. 188، p=0. 001 and -0. 391، p=0. 272 for BOP and -0. 219، p=0. 05 for GI، respectively. The present study showed that the effect of time was greater than the type of treatment on improvement of indices.

Local bone augmentation in the posterior maxilla (sinus lift) before the placement of dental implants has become an acceptable treatment technique in implant dentistry. However، limited documented data are available on the results of this technique and relevant issues in Iran. The present study aimed at evaluating the surgical outcome of sinus lift and implant placement in warfare victims presenting to Ghazi Tabatabai Clinic during 2001-2008. In this retrospective study، 50 patients that had undergone sinus lift surgery were evaluated. All warfare victims presenting to the clinic who had a medical record and undergone sinus lift treatment were enrolled. Those with incomplete medical files were excluded from the study. The required data were extracted from patients’ medical records and entered into a questionnaire. The mean duration of follow up was 53. 32±23. 05 months. The surgical success criterion was presence of osseointegrated implants in the oral cavity during the follow up period. Statistical analysis was performed using t-test and Fisher’s exact test. failed out of which 5 were in the sinus-lift area. Thus، the total success rate، the success rate of implants placed in the sinus lift area and the success rate of those out of the sinus lift area were 96. 6%، 93. 9% and 98%، respectively. The study results demonstrated high success rates for implants placed in sinus lift and non-sinus lift areas in warfare victims.

Considering the growing trend of information at the current era and development of educational patterns، transforming traditional education into e-learning is becoming increasingly popular. The present study was conducted to compare dental public health course offered through traditional training and e-learning. In this semi-experimental study، 70 senior (11thand 12thterms) dental students in Shahid Beheshti Dental School who took dental public health course in the first semester of 2010-2011 educational year were selected by census sampling method and assigned to the intervention or control group based on their term. Data were collected using the standard translated version of Distance Learning Attitude Survey (DLAS) questionnaire that was used after determining its validity and reliability. This questionnaire measured the success criteria of e-learning in students. The course was offered online to the intervention and as traditional classroom teaching to the control group for one semester. At the end of the course، a written examination was held for the students in both groups to evaluate their educational progress. Also، students’ satisfaction about the educational method was assessed using the translated version of Individual Development and Educational Assessment (IDEA) questionnaire after determination of its validity and reliability. SPSS software was used for data analysis. 36 students، were assigned to the e-learning instruction group13 (36. 1%) were males and 23 (63. 9%) were females. Thirty four subjects were assigned to the traditional classroom instruction group out of which 10 (29. 4%) were males and 24 (70. 6%) were females. In terms of demographic characteristics، the only difference between the two groups was in the daily computer usage. The mean± SD of the final examination score was similar in the two groups of e-learning and traditional classroom teaching and no significant difference was detected in this respect. Students’ satisfaction in the two groups was compared in five domains. The first 4 domains were the instructor’s teaching، the educational content، attitude towards the educational course، and difficulty of the course and no significant difference was detected between the two groups in the mentioned domains. The only significant difference between the two groups was observed in the fifth domain namely the final perception and judgment of students (P<0. 0001، 2. 93 versus 3. 85). All students successfully passed the course. No statistically significant difference was found between the two groups in terms of the knowledge gained about dental public health. E-learning method successfully achieved its objectives which were the development of positive attitude in students towards online education and obtaining their satisfaction. Given the necessary equipment and under certain conditions، e-learning can be successfully used as a substitute for traditional education in national dental universities.

The main reason for failure in application of fissure sealant is its loss of bond to tooth and development of secondary decays. Nanoparticles of hydroxyapatite have convenient biologic properties and we can try to benefit from these characteristics by adding them to repair materials. The present study was performed with the aim to assess the effect of addition of various amount nanoparticles of hydroxyapatite on mechanical properties such as microshear bond strength and physical properties like curing depth and degree of conversion as well as evaluation of teeth enamel remineralization.

In the present laboratory experimental studydifferent weight percentages comprising 0% (control)، 1%، 3%، 5%، 10% and 15% of nanoparticles of hydroxyapatite with 50 nm dimensions were separately added to fissure sealant. Then degree ofconversiontest by Fourier Transform Infrared Spectroscopy (FTIR) and curing depth according to ISO 4049 standard were performed on prepared samples. For the microshearbond strength test 35 premolar teeth without caries were used. The substance properties measurement device (Zwick) was used to do the test. Remineralization of permanent teeth enamel was assessed by Scanning Electron Microscopy (SEM). Raw data obtained were statistically analyzed by normal distribution test (Kolmogorov-Smirnov)، one way ANOVA and Tukey Post Hoc.

Results showed that microshear bond strength and degree of conversion had no significant difference in various concentrations of fissure sealant containing hydroxyapatite nanoparticles (P>0/05). Between microshear bond strength and degree of conversion means of 3M commercial fissure sealant and usual fissure sealant there was no significant difference (P>0/05). Curing depth in concentrations of 10% (P=0) and 15% (P=0) statistically significantly decreased compared to previous groups (P<0/05). Curing depth of 3M commercial fissure sealant group was lower compared to conventional fissure sealant group (P=0) and the difference was statistically significant (P<0/05). A remineralized region on the surface between the fissure sealant and tooth enamel was observed by SEM. This region was more remarkable in higher concentrations.

Fissure sealant containing hydroxyapatite nanoparticles with effect on remineralization on the surface of tooth enamel can lead to reduction of micro-leakages and prevention of development of secondary caries while mechanical properties do not decline.

The ancient Iranian medicine، before and after Islam، has a long and prolific history which has been emphasized by many famous historians like Andalosi (11th century AD). Dentistry was among the important fields related to medicine and ancient physicians were interested in it. This study aimed at reviewing the viewpoints of famous pioneer practitioners in Persia regarding various fields of dentistry. Accredited text books of the Persian Empire especially the Al-Hawiby Rhazes (865-925 AD)، Kamel al-Sana by Ali Ibn Abbas Ahwazi (930- 994)، and Avicenna’s Al-Qanun (980-1037) all authored in Arabic which was the scientific language of the time were thoroughly evaluated and topics related to dentistry were extracted from them and compared with contemporary dental science. Also، several dictionaries، encyclopedias and reference books were used for correct understanding of the meaning of ancient medical terms and idioms. The findings demonstrated that many of the topics mentioned in the ancient Iranian textbooks had a scientific foundation and are compatible and comparable with the contemporary dental science. Based on the results of the present study and similar previous researches، we can state that the ancient Iranian medicine is not at all distant from the contemporary science. It is the foundation of the contemporary medicine and further researches on the medical history of ancient Persia can reveal many valuable findings that can be used for educational، therapeutic and research purposes.

Various prosthodontic techniques are used for treatment of implant patients. Fabrication of a cement-retained prosthesis on a screw-retained framework is among these techniques. This type of prosthesis is usually indicated for implants that have been insertedobliquely or in an improper position. Easy retrieval، repair and maintenance are the main advantages of this type of prosthesis. The present articledescribes a method for fabrication of implant supported prosthesis. In this prosthesis، separate crowns are cemented on a screw-retained framework. The metal framework is coated with gingival-colored porcelain in order to support soft tissue. Case: Our patient was a completely edentulous 56 year-old female suffering from severe bone loss as the result of long term use of dentures. The bone resorption was so severe that the normal ridge contour could not be restored even after extensive ridge augmentationusing iliac crest bone graft. Thus، a combination of cement-retained and screw-retained prostheses was selected as the treatment of choice for this patient. This technique combines the advantages of both screw-retained and cement-retained prostheses in terms of function and esthetics. Also، despite the hardly-accessible location of the screw access channel in the framework، assessment of implants is always feasible by unscrewing the metal framework. Additionally، the fabricated crowns can be easily repaired or replaced without the need for unscrewing the framework.