فهرست مطالب alimohammad salari

Implant-supported overdentures are a treatment option for edentulous patients. One of the important factors in determining the prognosis of overdenture treatment is to control the distribution of stress in the implant-bone and attachment complex. This study assessed the effect of implant abutment height difference on stress distribution in mandibular overdentures.

In this study, three models of mandibular overdentures were designed independently using finite element analysis (FEA). The implants were placed at different height levels relative to the adjacent implant (1 mm, 2 mm and 3 mm). A 100 N load was applied to the overdenture, and the software was programmed for stress analysis in the models. The load was applied bilaterally, unilaterally, vertically, and obliquely. Finally, the von Misses stresses were produced numerically, color-coded, and compared among the models.

The models in which the implants had up to 2 mm height difference with each other showed better stress distribution than the model with 3 mm height difference between the implants. In all conditions, the implant neck showed the high-est concentration of stress among all areas of the implant. Lower stress levels were found in the cancellous bone than the cortical bone in different loading conditions.

Lower Von Mises stress values were found in the models with up to 2 mm difference in implant height, and higher stress values were noted in the cortical bone and the implant neck compared with trabecular bone.

With increasing age and inability to maintain good oral hygiene, the chances of tooth loss increase and the need for dental implants will increase in the future. It also increases the risk of developing peripheral implants, especially at older ages in the failure of implant treatments. Recently, the high prevalence of cardiovascular disease and peri-implantitis in the elderly has been reported. The aim of this study was to investigate the effect of cardiovascular disease on the peri-implantitis in people with failed dental implants.

In this retrospective study, the files of patients referred to Shahid Montazeri Dental Clinic from 2009 to 2018 whose their failed implants were extracted, were collected. There were a total of 793 people with failed dental implants. The variables of this study were demographic information including age and sex, health status in terms of cardiovascular disease and peri-implantitis, which were identified and then statistically analyzed by examining the files of patients with these two variables. Data were statistically analyzed by SPSS25 statistical software and Chi-square was used to determine the effective variables.

A total of 793 patients had failed dental implants, including 368 women (46.4%) and 425 men (53.6%) with an average age of 50.79 years. 42 patients (5.3%) had heart disease and 44 (5.5%) had peri-implantitis. According to the Chi-squared test, the significance level was less than 0.05 (P=0.011).

The results of this study showed that the cardiovascular disease and peri-implantitis were significantly related.

Special attention to the human resources at all stages of work, especiallyduring the end of work, will cause calm and confidence andgrowth and excellence in different dimensions, which can improve the processof work and better service of the organization. Therefore, the purpose of thisstudy is to formulate a retirement document in NAJA in order to provide welfare,support and relief services to retirees of the organization in an inclusiveand coordinated manner. The current research is practical and developmentthat is done in a mixed method. The method and volume of sampling used inthis research, in the documentary sector, is the total number method, and in theexpert and expert section, the method is a judgment and purposeful methodof 30 people. In this research, the researcher utilizes both methods of collectinginformation - field techniques and scientific and libraries. In order tocollect data, in the field method, the interviewing tool and the library methodalso used to scan all scientific and specialized books in the field of research,scientific articles and research papers, and organizational documents. In orderto analyze the collected data, the method of establishing expert meetings washeld with the participation of the honorary staff of the NAJA Center of RetirementAffairs and experts. According to the findings of this research, retirementissues can be considered in three phases as follows: 1. Pre-retirement withthree issues and three operational strategies. 2. Retirement phase with fourissues and six operational strategies. 3. After-retirement with six issues andfifteen operational strategies.

The manager experiences documentation is an undeniable necessity, Therefore, the purpose of this study is to present a model for developing managers' experiences with emphasis on the methods of documenting experiences. The statistical population of this study is 113 managers Which is at the strategic level and in the area of ​​government policy and national and military apparatus that work in the system of the Islamic Republic of Iran, in this study, a sample of 87 people was tested. The main tool of this study was first study documents, then free interview and finally a researcher-made questionnaire that Confirmed by verified experts, and then validated by Cronbach's alpha, its reliability (with a total reliability of 0.978) was confirmed and implemented. The results of this research have shown that documenting experiences involves expert selection approaches, forum, case-based arguments, storytelling and suggestion systems. Which is presented as five desirable methods for documenting managerial strategic experiences. In applying the above methods, the level of managers at the macro and organizational levels, identification of types of experiences, incorporating the rules and regulations governing the use of the discourse of the velayat-e fagih as the general policies of the Islamic system should be devoted to the methods of documenting the experiences of managers.

Surface roughness can increase the retention of castings by sandblast that are micro retentive. This study compared the retention of implant-supported crowns when used with 3 different surface roughness abutments and one temporary cement.

Thirty abutments (DIO implant- Cemented abutment،SAC 4814N(II)) were divided in three groups، first group was standard machine surface، second group sandblasted with 25 micron aluminum oxide particles and third group was sandblasted with 50 micron than ten regular diameter implant analogs were embedded in resin acrylic block and provisional cement kerr Temp bond NE was used for cementation. 90 metal coping were fabricated and after cementation the aging processing was done than the retentive strength was tested with universal testing machine at cross head speed of 0. 5 mm/min، results were analyzed using One way ANOVA and Tukey test.

Retentive strength of temp bond kerr with 50 micro sanbblasted abutment was statistically different than two other groups (P<0. 001). and between all the group standard abutment was weakest.

Surface modification of implant abutment by sandblast may be an effective method to increase retention of crown when provisional luting cement is used.

Using 2 implants in edentulous lower jaw is a standard protocol treatment for improvement of prosthesis retention. Different attachments have been produced in factories. One of these attachments is locator that is now a famous clinical option. In this in vitro study، the effect of inter implant distance on retention in simulated function condition and on 2 brands including Dio and 3i is analyzed. In this study، 24 nylon inserts pairs were provided from dio and 3i system attachment. Then، 2 hollow blocks with parallel walls were constructed. Attachments splinted to analogue and assembly inserted in block with GC reline materials in 2 inter implant distances of 19 and 23 mm and parallelism has confirmed with jelenko surveyor. The samples were assembled in zwick jaws and every sample was loaded at 1440 cyclic loading from vertical. Data is measured at cycles of zero، 120، 360، 720، and 1440 with 34560 cyclic loading exerted. Data were analyzed with proper statistical tests. Results and The results were analyzed with one-way analysis of variance (ANOVA). It was found out that retention value in 23 mm distance was greater than 19 mm until 720 cycles and difference was significant but at 1440 cycles، there was no significant difference.

The purpose of this investigation was to assess the prevalence of edentulous patients in Iran during 1998-1999. Edentulouness is a good indication of evaluating oro-dental health status inapulation. The aim of this cross-sectional study was to evaluate the prevalence of edentulous cases in people above 35 years in threecities of Iran. (Torbat-e-heidarieh in the west, Yazd in the center and Hamadan in the east).Methods & Materials: The study was carried out by means of a question aire as well as clinical examination with random sampling out at 1191 participants. The percentages of edentuluseness were 52.4% in Hamadan, 32.8% in Torbat-e-heidarieh and 40.7% in Yazd, while 5.78% in Hamadan, 3.4% in Torbate heidarieh and 6% in Yazd had all their 28-32 teech. Results of this study showed that edeutulousness had significant relation with the following factors: Age, education, Oral health status. There was no significant relationship between gender and edentulousness.