Showing 8 results for Dental Implants
V. Mortazavi , Mh. fathi ,
Volume 13, Issue 1 (4-2000)
Abstract
Characterization of bioceramics coating and evaluation of the influence of kind of coating on the implantation has been developed in recent years.Different bioceramics coating like calcium phosphate, hydroxyapatite, fluorapatite and bioglass were coated on dental and orthopedic implants. In-vitro and in-vivo experiments were done for evolution of implant success and reliability and study of factors, which may influence the results.Researches indicate that different bioceramic coating may affect the bone bonding mechanism.Biodegredable calcium phosphate coating can be resorbed and be replaced with bone tissues.Hydroxyapatite cause earlier stabilization of dental implant in surrounding bone (biological fixation) and reduce healing time. Bioglass can protect substrate and provide interfacial attachment to bone.
M. Paknegad , A. Miremadi , M. Tabatabaei-E-Yazdi , M. Khodadad-E- Motarjemi ,
Volume 16, Issue 2 (5-2003)
Abstract
Statement of Problem: The correlation between the activity of aspartate aminotransferase (AST) and alkaline phosphatase (ALP) enzymes in gingival sulcular fluid (GCF) with inflammation and periodontal attachment loss has been proved, however there are not adequate studies about dental implants.
Purpose: The aim of present study was to investigate the presence and activity level of AST & ALP and their correlation with pocket depth (PD) and bleeding of peri-implant slcular fluid (PISF), and to evaluate the possibility of using these assessments as a diagnostic index in oral implantology.
Material and Methods: In this study, 41 implants as test group and 41 contralateral teeth as control group, in 21 patients were evaluated. At first visit, the general information about implants and the values of pocket probing depth (PPD), modified sulcus bleeding index (mSBl) and modified plaque index (mPI) were recorded. At the second visit, samples of GCF/PISF were collected. AST & ALP activity was determined spectrophotometrically and data were analyzed by "t", "Mann-Whitney" tests and Pearson Spearman correlation coefficient.
Results: The results showed that there was a significant difference in the activity of AST between two study groups (P<0.0001). The average activity of ALP in test group was more than control group but the difference was not significant. After elimination of the confounding variables, the average AST in test group was 54.6 (S£=2.3) and in control groups was 44.8 (SE=2.3) (P=0.004). The average ALP in test group (SE=2.2) and in control (SE=2.2) were 36.6 and 35.4, respectively. Values of AST and ALP were positively correlated with other clinical parameters such as PD and mSBI which was significant in test group.
Conclusion: The present study suggests that PISF analysis could be considered as a proper diagnostic strategy in the evaluation of dental implant success.
M. Panjnosh, H. Siadat, M. Alikhasi, M. Alihoseini,
Volume 22, Issue 2 (11-2009)
Abstract
Background and Aim: It is well recognized that implant treatment is common worldwide, but the approach to success is not predictable because of bone loss that occurs around the implants. Also there are many factors affecting crestal bone loss around the implants that one of them is the surgical protocol of implant installation. The purpose of this investigation was to evaluate the amount of crestal bone loss around the Replace implants installed according to submerged and non- submerged treatment protocol.
Materials and Methods: In this study, 11 patients received 34 implants. In each patient (unilateral or bilateral mandible), one of the implants was placed with submerged procedure and in the other one non- submerged procedure was used. In a period of 3 months a temporary partial denture that covered the implants was used. After 3 months the submerged fixture was exposed, impression was performed and fixed prosthesis was fabricated. Loss of crestal bone at each implant was measured. These measurements have been done at surgical times, over a period of 3 months after implant installation and 6 months after the delivery of the fixed prosthesis. The measurement was done with digital subtraction radiography. Data was analyzed by Wilcoxon Signed Ranks test.
Results: Three months after implant placement, submerged groups showed statistically more crestal bone loss (0.65±0.71) than non-submerged (0.41±0.53) group (p=0.02). After 6 months the mean value of crestal bone loss in submerged group was 0.21±0.40 mm and in non submerged group was 0.29±0.49 mm. This data indicated no statistically significant difference between the two groups of implants (p>0.05).
Conclusion: Our results are in accordance with previously published studies and confirm that the value of crestal bone loss in submerged and non-submerged groups after 3 and 6 months were similar and in acceptable limit.
Mohamad Reza Khalili, Babak Ziaie, Mahmoud Kazemi,
Volume 26, Issue 4 (1-2014)
Abstract
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.
Mahmod Kazemi, Saeed Nokar, Ahmad Rohanian, Adel Pazhohan,
Volume 26, Issue 4 (1-2014)
Abstract
Background and Aims: 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.
Materials and Methods: 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.
Results: 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.
Conclusion: 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.
Somayeh Zeighami, Hakimeh Siadat, Marzieh Alikhasi, Zeinab Saeidi,
Volume 30, Issue 1 (6-2017)
Abstract
Background and Aims: Taking impression from angulated implants has always been a great challenge in clinic. In this regard, studies on sectional trays are very few. The aim of this study was to evaluate and compare the dimensional and angular accuracy of impressions using full arch and sectional trays.
Materials and Methods: Four implants (4.3 × 12 mm) (Implantium, Dentium) were placed in the first premolar and molar regions of a Kennedy class I mandibular acrylic model with 30° lingual angulation. Twenty open special trays (Full arch & Sectional) were made on the primary cast. The impressions were taken using vinyl polysiloxane (VPS) and were poured with type IV dental stone. The coordinate measuring machine (CMM) was used to measure the dimensional (Z, Y, X) and angular (θ) coordinates of implants. The data were analyzed using and t-test and SPSS 22. Software.
Results: The type of tray had no significant effect on the dimensional accuracy in X, Y and Z axes (P>0.05) and total linear displacement (r); However, it significantly affected the angular accuracy (∆q) (P<0.05).
Conclusion: Sectional tray yields less rotational displacement in impressions made of angulated implants.
Somayeh Zeighami, Marzieh Alikhasi, Maryam Memarian, Moeen Hosseini Shirazi,
Volume 30, Issue 4 (1-2018)
Abstract
Background and Aims: For the clinical success of implant-retained prostheses, fitness of matching components and stability of the applied torque to the implant-abutment assembly under dynamic occlusal loading is essential. The aim of this study was to evaluate the torque loss in Co-Cr castable abutments after cyclic loading.
Materials and Methods: 10 castable abutments were cast in Co-Cr alloy with similar size and height. Each specimen was mounted vertically on a separated implant using a 30 Ncm tightening torque. The detorque values of the abutments were evaluated after 10 min. The same tightening torque was applied to the abutments on their corresponding implants and cyclic loading was applied for 500,000 cycles to the implant-abutment assembly. The torque values after cyclic loading were recorded for each specimen. T-test analysis was conducted on scores from the groups.
Resultes: The results of this study showed that the percentage of torque loss in castable abutments was significantly increased after cyclic loading (P<0.001).
Conclusion: Misfit between the castable implant components can cause torque loss before and after cyclic loading. However, it is more appropriate to relate the results of this study to the screw loosening of the above mentioned abutments than judging their clinical performance.
Hosnie Yusefi Fakhr, Yadollah Soleimani Shayesteh, Afshin Khorsand, Mehrdad Panjnoush, Mohammad Javad Kharazi Fard, Mohadeseh Heidari,
Volume 35, Issue 0 (5-2022)
Abstract
Background and Aims: According to the importance of primary stability on dental implant success and osseointegration, we intend to check and compare the stability and crestal bone loss rate between osteotomy technique and conventional implant insertion techniques.
Materials and Methods: In this study, 26 implants in anterior segment of maxilla in 13 patients were evaluated. The implants were TBR system (Toulouse, France) with 3.5 diameter and 10.5-12 mm length. The implant stability level was recorded immediately after surgery and 3 months later with Ostell mentor. The periapical radiography was taken immediately after surgery, 3 and 6 months to assess crestal bone resorption. Paired t-test and Wilcoxon signed Rank test used for data analysis.
Results: There were no statistically differences between the two treatments techniques in terms of stability (P>0.05). The mean crestal resorption was higher for the osteotomy technique 3 months after implant insertion (P<0.001) but there were no significant differences after 6 months (P=0.678).
Conclusion: Within the limitations of the current study, it can be concluded that the osteotomy it can be considered as a treatment technique in insufficient bone width.
