مجله دندانپزشکی دانشگاه علوم پزشکی تهران
سال بیست و ششم شماره 4 (پیاپی 77، زمستان 1392)

One of the important aspects for evaluating an organization is assessing the level of satisfaction of the clients. This study was conducted to compare the level of satisfaction between traditional and new methods of delivering dental care in the clinic of Tehran University of Medical Sciences. A cross-sectional study was conducted on 308 patients received dental care at the dental clinics of Tehran University of Medical Sciences in spring 2010. Data were collected from Comprehensive Care Unit (CCU) in addition to 7 isolated clinics including restorative، periodontics، endodontics، radiology، and prosthodontics (fix and removable) using translated version of the Dental Satisfaction Questionnaire (DSQ)، consisted of 19 questions in three main domains in addition to demographic questions. Descriptive statistics was used as percentage of answers. In order to compare the mean score between domains ANOVA test was used. The standardized mean scores in each domain were: pain control 58±17، access 59±12، quality 68±11 and total Dental Satisfaction Index (DSI) score of 62±10. 92. 5% of the respondents reported that students were very careful when examining their patients. 96. 8% reported that they treat their patients with respect. The most common reasons for dissatisfaction apart from waiting time and getting appointments were not providing preventive care and pain control. The results of this study shows acceptable level of satisfaction with dental care in teaching clinics of this dental school، however efforts on implementing preventive care and pain control strategies are suggested.

Making accurate impressions of prepared teeth when they are adjacent to dental implants is of great importance. In these situations، disregarding the selection of appropriate impression material and technique، not only can affect accuracy of transferring of the 3-dimentional spatial status of implant، but also can jeopardize the accurate recording of tooth. In the present study، the accuracy of two impression materials with taper impression copings for recording implant position and surface details was evaluated. One metal reference model with 2 implants (Implantium) and a preparation of three grooves on a tooth according to ADA no. 19 standard was fabricated. 10 medium- consistency polyEther (PE) impressions using custom trays and 10 polyVinyl Siloxane (PVS) putty wash impressions using prefabricated trays with conical impression coping were made. Impressions were poured with ADA type IV stone. A Coordinate Measuring Machine (CMM) evaluated x، y and angular displacement of the implant analog heads and also accuracy of groove reproduction were measured using a Video Measuring Machine (VMM). These measurements were compared to the ones from reference model. Data were analyzed using one-way ANOVA and T-test. Putty wash PVS had less linear discrepancy compared with reference model (P > 0. 001). There was no significant difference in the surface detail reproduction (P = 0. 15). Putty wash PVS had better results for linear displacement compared with medium consistency PE. There was no significant difference in surface detail reproduction between the two impression materials.

Retention and stability of the post and core system is the key factor for success of final restoration. The aim of this study was to evaluate the microtensile bond strength of the different composite core materials and bonding systems to a fiber post. To evaluate the bond strength of the composite resins to a fiber post (DT light post) 60 posts were divided into six groups: group A: Heliomolar Flow + Seal Bond، group B: Heliomolar Flow + SE Bond، group C: Valux Plus + Seal Bond، group D: Valux Plus + SE Bond، group E: Corecem + Seal Bond، group F: Corecem + SE Bond. All samples were thermocycled for 5000 cycles (5-55 0C) and cut into four bars for the microtensile bond strength test. Failure modes were identified using a stereomicroscope. Data were analysed using One-way ANOVA and Tukey HSD post hoc test (P<0. 05). The interaction between composite resin materials and bonding systems were positive. The conventional hybrid composite (Valux Plus) had significantly higher bond strength compared with the core specific flowable composite (Corecem) when Seal Bond was applied as bonding agent (P<0. 05). However، when SE Bond was utilized hybrid composite demonstrated significantly lower bond strength than that of other two groups (P<0. 05). The performance of a particular composite is affected by the bonding system that is applied. A single composite resin may have different bond strength when combined with different bonding system.

According to the common application of non-metal prefabricated posts in dentistry and lack of enough information about the stress distribution in the root canal walls by these posts، this study was performed to compare the effect of two simple taper and double taper posts on the stress distribution on root canal walls by photo elastic method. The design of this study was experimental in photoelastic system. The posts، used in this investigation، were double taper and simple taper fiber posts with 0. 9 mm diameter and 20 mm length and epoxy resin. First two photo elastic models with tooth dimensions were fabricated and the posts were placed inside the model. Then the core of the each post was fabricated on the model. Each models were loaded in polariscope and the formed fringe order colored ring were photographed. In 100 N، 90 degree angle loading in cervical and apical fringe order showed 2. 50 and 1. 39 in simple taper posts and 1. 39 and 2. 35 in double taper post. In 150 N، 30 degree angle loading in cervical and apical fringe order showed 4 and 2. 65 in simple taper posts، and 4 and 2. 5 in double taper post. In the vertical and oblique loads، double taper fiber post showed better stress distribution than that of simple tapered posts.

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. 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. 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. 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.

Thermal changes in the oral cavity can be transferred to the implants placed in bone and affect the prognosis of the treatments. Furthermore، some investigators proposed improvement of habitual consumption of hot or cold beverages. The aim of the present study was to measure the effect of temperature changes in the oral cavity following consumption of hot and cold drinks on the temperature of implant. In this clinical trial، 3 eligible patients were selected. Two months after implant insertion، temperature of the implants was measured following the drinking of hot and cold beverages using a sensor connected to a thermometer. The thermal changes of the implants through the different time intervals were analyzed using Friedman non-parametric test. The implant temperatures were significantly increased in the time following drinking of the hot beverages (P=0. 009). Furthermore، the implant temperature were statistically decreased in the time after drinking cold beverage (P=0. 004). When drinking hot beverages، the maximum and minimum temperatures were 41. 57 0 C and 36. 77 0 C، respectively. The maximum and minimum temperatures of the implants were also 34. 13 0 C and 26. 83 0 C، respectively، when drinking cold beverages. It seems that the temperatures noted in the implants in the current study cannot weaken the prognosis of implant restorations; however، habitual consumption of hot and cold beverages can lead to debilitating implant prognosis and therefore، should be given the necessary warnings to patients.

Impacted third molar reduces the bone level in the distal aspect of second molar، and sometimes it can lead to root resorption of the adjacent tooth. The purpose of this study was to determine this resorption using panoramic and periapical radiographs. In this cross-sectional descriptive study 54 patient (28 men، 26 women) above 15 years old with the average of 22 years in Oral and Maxillofacial Department of Tehran University were studied. A periapical radiography from the third molar and a panoramic radiograph were taken from each patient (Because of their routine use and evaluation of accuracy of panoramic compared with periapical)، and the magnitude of the root resorption for the second molar was determined by 2 observers and written in a questionnaire. Data were analyzed using Fisher test. The prevalence of the root resorption of the second molar adjacent to the impacted third molar in the panoramic and the periapical radiographies، with respect to the limitation of the sample size were 46. 3% and 31. 5%، respectively، with 95% confidence (P>0. 05). Most of these resorptions were in the cervical third of the second molar roots and in cases in which the third molars were mesially oriented or horizontal. There was also no significant difference between panoramic and periapical radiographs. Due to the increased risk of the resorption of the second molar adjacent to the third molar، extraction of the impacted third molars، especiall y mesially oriented or horizontal ones are recommended.

Application of fluoride products is known as one of the most successful interventions to prevent dental caries. This study aimed to compare the costs of in-office fluoride therapy versus salt fluoridation in Iranian population. In this study، the costs relating to the use of in-office fluoride therapy were analyzed using Activity Based Costing during 2011 from two perspectives. From the perspective of service provider، direct medical costs and indirect costs and from the view of service recipient، three parts: direct medical and non-medical costs and indirect costs، were considered. Costing for public consumption of salt fluoridation was estimated based on salt processing costs، including purchase، installation، monitoring، maintenance and repair of machinery، equipment، personnel expenses and cost of raw materials، used in this study. Costs relating to performing a single in-office fluoride therapy was estimated to be 245،032 Rials from the perspective of service providers، and 239،600 Rials from the patient view. Estimated total cost to produce fluoridated salt for a unit of 10 million populations، was calculated to be 35 billion and 940 million Rials or 3، 594 Rials per person per year. It was concluded that per-capita costs of community based salt fluoridation was far less than in-office fluoride therapy. Salt fluoridation could be advised to be an affordable way to prevent dental caries in Iranian population.

As midwives are in frequent contact with pregnant mothers، they may play a key role in their oral health care (OHC). In this study، we aimed to evaluate the effect of an educational program on Tehran University of Medical Sciences midwifery students’ knowledge and preparedness on OHC in pregnant mothers. The midwifery third year students of central campus (n=29) were randomly selected as intervention group and their counterparts in Hemmat campus (n=33) as control. Students in both groups were asked to fill in a questionnaire included 8 demographic question and 18 OHC knowledge and one question on their preparedness to implement OHC. Then the educational intervention was implemented using lecture، demonstration of the correct methods of brushing and flossing on the models and role play method. The follow- up questionnaire was delivered 3 months later. Data were analyzed using Mann-Whitney test، T-test، Chi-Square test، ANOVA and Regression by SPSS software. The mean OHC in pregnancy knowledge score in intervention and control group were 26. 7 and 24. 8 at baseline which were changed into 48. 5 and 29. 1، respectively (P<0. 001). Among the students 52. 6% in the intervention group and 36. 4% in the control group reported very high preparedness to implement OHC in pregnancy. These figures were 68. 2% and 41. 7% in the post-test. The promising findings of this educational intervention comprising of both student and teacher-centered methods speak for possibility of improving these students knowledge and preparedness and implies on the necessity to incorporate the related course in midwifery education.

Occurrence of medical emergencies in dental offices is not uncommon. The most important and the first step in controlling the medical emergencies is the ability to provide basic life support which needs knowledge، experience and equipments. The aim of this study was to investigate the knowledge of dentists relating to the management of medical emergencies in dental office and their willingness towards holding related educational workshops.

This analytic cross-sectional research was accomplished in Babol among 132 general and specialist dentists in 2010. A validated questionnaire (Knowledge and attitudes of reliability: Cronbach''s α value 79% and 84% respectively) consisting of 17 questions about knowledge (score of 14-17: excellent، 11-14: good، 8-11 moderate and less than 8: poor)، three questions about attitude and demographic characteristics was distributed. Data were analyzed using t-test، X2 and Pearson correlation statistics using SPSS.

119 dentists (91. 9%) filled out the questionnaire. The average age was 38. 6 (± 7. 5) years with 84 (70. 6%) male and 35 (29. 4%) female individuals. The average score of knowledge was 9. 31 (± 2. 31) out of 17 points which was negatively correlated to the graduation year (r=-0. 43) and age of dentists (r=-0. 3). 94% were agreed with workshops and 75% were agreed with equipment of office and emergency kit and 84. 9% were not satisfied with the academic education in that field.

Knowledge of dentists in Babol was not sufficient in the field of medical emergencies which needs intervention for improving and updating by means of holding workshops and continuing education program.

The aim of this study was to evaluate the effect of chlorhexidin 2%، sodium hypochlorite 2. 5% and hydrogen peroxide 3% as three effective and regular disinfectants on the microleakage of 7th generation bonding agents in vitro. 45 extracted molar teeth without carries were collected and disinfected. On buccal and lingual aspects of these teeth conventional class V cavity preparation were done (90 cavities)، then randomly divided to 4 groups، three of them had 10 teeth (20 cavities) and one of them had 5 teeth (10 cavities) as control group. Cavities in each experimental group prepared with one of the disinfectants and then 7th generation bonding (Optibond all in one، kerr) was used as noted by manufacturer، then cavities filled with composite and polished. Bonding agent was used without our previous disinfectants manipulation in control group. Specimens were thermocycled with 1000 thermal cycles between 5 and 55 0 C each for 30 seconds and then immersed in the methylene blue 5%، then sectioned mesiodistally and investigated for microleakage under stereomicroscope (Olympus، Japan). Data were analyzed using Kruskal-Wallis and Wilcoxon mean rank tests. Despite the lower mean rank values for the untreated group at both occlusal and gingival aspects، the Kruskal-Wallis procedure (α=0. 05) showed that the treatment factor did not significantly affect the mean rank values neither in occlusal (P=0. 12) nor in gingival (P=0. 39) part of cavities. According to the results of this study، antimicrobial agents such as chlorhexidine 2%، sodium hypochloride 2. 5% and hydrogen peroxide 3% can be used perior to 7th generation dentin bonding agent (Optibond all in one، kerr) without much concern.