Application of virtual reality in dental implants: a systematic review.

BACKGROUND AND OBJECTIVE: A treatment approach that is widely used as a permanent and natural replacement for missing or extracted teeth is dental implants .VR is a computer-generated simulation that creates a three-dimensional (3D) image or environment. Advances in VR -based learning allow learners and students to practice and also help professionals plan a wide variety of surgical procedures, including the correct placement of dental implants. Therefore, in this systematic review, our aim was to investigate and evaluate the available virtual reality tools for dental implants and their effectiveness. MATERIALS AND METHODS: Studies published up to 01/30/2023 which report the applications of using virtual reality technology in dental implants, were reviewed in three databases, including PubMed, Web of Science, and Scopus. All studies with evidence reporting the role of virtual reality technology in the field of dental implants were included in our analyses, written in English and published in peer-reviewed form, are included. Theoretical articles, and letters that did not provide original data, as well as studies that reported incomplete information, were excluded. Two reviewers independently assessed search results, extracted data, and assessed the quality of the included studies, and decisive agreement was reached by discussion and consultation with the third researcher. Narrative synthesis was undertaken to summarize and report the findings. RESULTS: Out of 1633 initial search results, nine were included in the present study based on the inclusion criteria. The focus of seven studies was on teaching and learning, and two studies have examined the implant planning procedure. The most commonly used hardware and software were head-mounted display and Unity3D, respectively. In almost all studies, the results showed that the use of virtual reality-based systems improves and enhances the skills of users, including dental students and specialists. CONCLUSIONS: Our findings showed that VR is an effective method for teaching and planning the implant process. Although the use of VR technology is limited for various reasons such as cost, it can increase the skills of dental professionals in performing dental implants.

The Antibacterial Effects of Healing Abutments Coated with Gelatincurcumin Nanocomposite.

INTRODUCTION: For the long-term success of implant treatment, prevention of biological complications, including pre-implant diseases, plays an important role. The use of antimicrobial coatings is one of the prosperous methods in this field. The aim of this study is to evaluate the antimicrobial effects of healing abutments coated with gelatin-curcumin nanocomposite. METHODS: This study included 48 healing abutments in the form of a control group (titanium healing abutments without coating) and an intervention group (titanium healing abutments coated with gelatincurcumin nanocomposite). The disc diffusion method was used to evaluate the antimicrobial effects of coated healing abutments against Escherichia coli, Staphylococcus aureus and Enterococcus faecalis and the results were reported in a non-growth zone area. RESULTS AND DISCUSSION: Gelatin-curcumin nanocomposite caused significant non-growth aura for all three bacteria compared to the control group. For the control group (healing abutments without coating), the antimicrobial effects (non-growth zone) were zero. Besides, gelatin-curcumin nanocomposite had the greatest inhibiting effect on the growth of S. aureus, then E. coli and finally E. faecalis. CONCLUSION: The results of our study showed that the coating used was able to significantly demonstrate a non-growth zone against all three bacteria compared to the control group without coating. Further evaluations in various physicochemical, mechanical, and antimicrobial fields are necessary for the animal model and clinical phase.

Promising Antimicrobial Action of Sustained Released Curcumin-Loaded Silica Nanoparticles against Clinically Isolated Porphyromonas gingivalis.

BACKGROUND: Porphyromonas gingivalis (P. gingivalis) has always been one of the leading causes of periodontal disease, and antibiotics are commonly used to control it. Numerous side effects of synthetic drugs, as well as the spread of drug resistance, have led to a tendency toward using natural antimicrobials, such as curcumin. The present study aimed to prepare and physicochemically characterize curcumin-loaded silica nanoparticles and to detect their antimicrobial effects on P. gingivalis. METHODS: Curcumin-loaded silica nanoparticles were prepared using the chemical precipitation method and then were characterized using conventional methods (properties such as the particle size, drug loading percentage, and release pattern). P. gingivalis was isolated from one patient with chronic periodontal diseases. The patient's gingival crevice fluid was sampled using sterile filter paper and was transferred to the microbiology laboratory in less than 30 min. The disk diffusion method was used to determine the sensitivity of clinically isolated P. gingivalis to curcumin-loaded silica nanoparticles. SPSS software, version 20, was used to compare the data between groups with a p value of <0.05 as the level of significance. Then, one-way ANOVA testing was utilized to compare the groups. RESULTS: The curcumin-loaded silica nanoparticles showed a nanometric size and a drug loading percentage of 68% for curcumin. The nanoparticles had a mesoporous structure and rod-shaped morphology. They showed a relatively rapid release pattern in the first 5 days. The release of the drug from the nanoparticles continued slowly until the 45th day. The results of in vitro antimicrobial tests showed that P. gingivalis was sensitive to the curcumin-loaded silica nanoparticles at concentrations of 50, 25, 12.5, and 6.25 µg/mL. One-way ANOVA showed that there was a significant difference between the mean growth inhibition zone, and the concentration of 50 µg/mL showed the highest inhibition zone (p ≤ 0.05). CONCLUSION: Based on the obtained results, it can be concluded that the local nanocurcumin application for periodontal disease and implant-related infections can be considered a promising method for the near future in dentistry.

Gelatin-Curcumin Nanocomposites as a Coating for Implant Healing Abutment: In Vitro Stability Investigation.

Regarding the importance of preventing peri-implantitis in dental implants, the current study aimed to coat a healing abutment with gelatin−curcumin nanocomposites, and the stability of this coating on the healing abutment was evaluated. A cell viability measuring test was used to determine the cytotoxicity of nanocomposites against dental pulp stem cells. To show the pattern of curcumin release from nanocomposites, drug dissolution apparatus two was applied. Then, 16 healing abutments were examined in vitro. Titanium healing abutments were coated with the gelatin−curcumin nanocomposite. The dip coating method was applied for coating and the consistency of coated cases was evaluated at intervals of one, 30, and 60 days after coating inside the simulated body fluid (SBF) solution. A scanning electron microscope (SEM) was used for investigating the microstructure and morphology of coatings, and an energy dispersive X-ray (EDX) was applied for determining the combination of the coating. Moreover, the healings were weighed before and after coating via an accurate digital scale with an accuracy of 0.0001. Finally, the data were analyzed using SPSS software. The prepared nanocomposite was non-cytotoxic against tested cells. The nanocomposite showed a relatively rapid release pattern in the first 10 days for curcumin. The release of curcumin from the nanoparticles continued slowly until the 30th day. The weight changes were statistically significant (p-value < 0.001) during this time. Based on the post hoc test, the weight between two times immediately after coating and 30 days after coating, and also one day after coating and 30 days after coating, was statistically insignificant. The results revealed that the coating of the gelatin−curcumin nanocomposite on the healing was successful and this consistency was kept for at least one month. It is necessary to investigate more evaluations in different fields of physicochemical, mechanical, and antimicrobial aspects for coated healing abutments.

Effect of Adding Silica Nanoparticles on the Physicochemical Properties, Antimicrobial Action, and the Hardness of Dental Stone Type 4.

This study was conducted to investigate the effect of adding silica nanoparticles on the physicochemical properties, antimicrobial action, and the hardness of dental stone type 4. Dental stone type 4 powder was physically mixed with nanoparticle powder at weight percentages (0, 0.5, 1, and 2 percent). The required amount of powder was added to water according to the manufacturer's instructions. The prepared set materials were subjected to the physicochemical studies; Fourier transmission infrared spectroscopy (FTIR) was taken up to investigate the functional groups and X-ray diffraction (XRD) was used to evaluate the crystallinity. Also, scanning electron microscopy (SEM) was used to examine the morphology of the prepared samples. Agar diffusion test was carried out for the prepared samples against the Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) to test the average growth inhibition zones. Finally, the Vickers surface hardness test was performed for each group using a hardness tester. The adding silica nanoparticles to dental stone type 4 increased the diameter of inhibition zones for the groups in both bacteria significantly (p < 0.05). The results showed that adding silica nanoparticles to dental stone type 4 increased the diameter of inhibition zones for the groups in both bacteria significantly (p < 0.0001). There was a significant difference between all groups and the 0% group in both bacteria (p < 0.0001). Besides, the adding of silica nanoparticles to dental stone type 4 increased the surface hardness significantly (p = 0.0057) without any effect on physicochemical properties. The 0% and the 0.5% groups had significant differences with the 2% group (p = 0.0046 and p = 0.0205 respectively). Then, at least 2% silica nanoparticles are needed for a significant increase. Clinical trials are needed to enlarge for dental stone type 4 containing silica nanoparticles in the future.

Comparison of the accuracy of fixture-level implant impressions using two different materials for splinting.

Background. Various materials are used for splinting impression copings, the most common of which are auto-polymerizing resins. In this study, a new light-curing pattern resin (Jig-Gel) was investigated and compared with auto-polymerizing resins using two different splinting methods. Methods. After taking impressions with two different materials, a digital caliper with an accuracy of 0.01 mm was used for splinting and measuring the distances between the external parts of the analogs inside the plaster cast. The accuracy was also compared in five groups as follows; group 1: splinting of impression copings by auto-polymerizing acrylic resin, group 2: cutting the splinting of impres-sion copings with self-polymerizing acrylic resin, group 3: splinting of impression copings with a light-cured resin pattern (Jig-Gel), group 4: splinting of impression copings cut by a light-cured resin pattern, and group 5: impression with no splint. All statistical analyses were performed with SPSS 17. Statistical significance was set at P<0.05. Results. The highest impression accuracy was obtained in the group without cutting the splint of the impression copings using auto-polymerizing acrylic resin. Compared with the impression methods, impression making of non-splint samples in an impression coping was the least accurate, and the results for the two used methods were similar. Conclusion. The results of this study showed that the combination of the impression coping method and auto-polymerizing acrylic resin had the highest accuracy.

Comparison of the Accuracy of Fixture-Level Implant Impression Making with Different Splinting Techniques.

OBJECTIVES: The impression-taking technique is one of the most critical factors that not only prevents the shrinkage caused by polymerization but also enhances the accuracy of implant impressions. Also, choosing the right time of taking impressions after splinting implants is one of the important criteria that affects the impression-taking technique. Accordingly, the present study aimed to evaluate the accuracy of different splint methods for implant impressions made at different times. METHODS: In this in vitro study, a two-piece metallic index was prepared, and the patient's jaw was simulated by placing self-cured acrylic resin in the lower part of the index. Then, two holes were made in the acrylic resin at a specific distance from each other, and the analogs were placed in these holes. Splinting of impression copings was carried out with autopolymerized acrylic resin (GC Pattern resin LS, GC America Inc., USA), and an open tray impression approach was performed. Thirty-six casts in three groups (n = 12) were fabricated from the acrylic model. After scanning the casts, the impression accuracy was compared between the three study groups by measuring the distance between the outer portions of the scan bodies screw-retained on implant analogs inside the cast using the Exocad software (2015.07 version). Group 1: splinting impression copings with autopolymerized acrylic resin and impression making immediately after the setting time (4 minutes); group 2: splinting and impression procedure after 17 minutes with splint sectioning and reconnection; group 3: splinting and impression procedure after 24 hours with splint sectioning and reconnection. The data were analyzed using SPSS 17 using the Kruskal-Wallis test. RESULTS: The mean distance measured in group 1 was 19.14 ± 0.029 mm, which was significantly lower than the main model. The distances were 19.15 ± 0.039 and 19.159 ± 0.33 mm in groups 2 and 3, respectively. These two groups were not significantly different from the main model. Moreover, the mean distance measured in the three impression techniques was similar. CONCLUSIONS: There was no significant difference in the measurements between group 2, group 3, and the main model. Therefore, dentists can make an impression after 17 minutes to reduce chair time.

Examining the quality of the competency-based evaluation program for dentistry based on the CIPP model: A mixed-method study.

Background. Continuing assessment of the quality of evaluation programs promotes the quality of exams and ensures learners' accurate evaluation. This study aimed to examine the quality of the competency-based evaluation program for dentistry based on the context, input, process, and product (CIPP) model. Methods. In a mixed-methods study (quantitative-qualitative), dentistry students' evaluation program using competency-based assessment methods was examined by dentistry professors based on the CIPP model and via a reliable and valid researcher-made questionnaire. The questionnaire had three sections on demographic information, evaluation questions, and open-ended questions. Descriptive statistics (mean and SD) were used to analyze the questionnaire items. Open-ended questions were analyzed by content analysis, and the quantitative part was analyzed using SPSS. Results. Twenty-five faculty members from the departments of orthodontics and dental prosthesis completed the questionnaires. The overall level of faculty members' satisfaction with the new evaluation program was above average (54±17.02). They had the highest degree of satisfaction with output indices and the lowest degree with input indices. The analysis of the open-ended questions yielded two general categories of "providing the human and physical infrastructure" and "spiritual support and encouragement of educational innovation." Conclusion. The competency-based evaluation program needs the support of managers and planners. The faculty should provide the infrastructure for the implementation of these methods. By meeting the requirements, the professors will be motivated to implement these methods, and the paradigm can shift from traditional to novel evaluation methods.

Effect of different geometric changes in the dental implant abutment body on the amount of residual excess cement and retention in a cemented implant-supported prosthesis.

BACKGROUND: Fixed implant-supported restorations are mainly used in dental implantology. In comparison with screw-retained implants, cement-retained prostheses have the following advantages: the ease of splinting implants; increased passive casting; and procedural similarity to conventional tooth-supported fixed partial dentures. Furthermore, they show reduced fracturing of components with better esthetic outcomes and an improved force direction, along with a reduced cost and less chairside time. OBJECTIVES: The aim of this study was to evaluate the effect of different geometric changes in the dental implant abutment body on the amount of residual excess cement (REC) and the retention of cemented implant-supported prostheses. MATERIAL AND METHODS: Seventy-two straight abutments were categorized into 4 groups: vertical groove; 1 horizontal groove; 2 horizontal grooves; and ccontrol (with no geometric changes in the abutment). The access hole was partially filled and the cast copings were cemented using Temp-Bond™ NE, a non-eugenol cement. The difference in weight before and after removing the excess cement was considered as REC. Furthermore, the retention of the cast coping was measured as the force that was required to separate the cemented cast coping from the abutment. RESULTS: The mean REC values of the groups with 1 and 2 horizontal grooves were significantly different as compared to the control group (p < 0.05). CONCLUSIONS: This study shows that the presence of 1 or 2 horizontal grooves in the abutment body significantly reduces the amount of REC in comparison with control.

Effect of tetracycline on IL-1ß and IL-6 levels of the peri-implant sulcular fluid.

Background: Inflammation in the implant-abutment interface is one of the main factors that can reduce implant stability. Therefore, this study investigated the effect of chlorhexidine, tetracycline, saliva, and a dry environment on the interleukin IL-1ß and interleukin IL-6 levels of the gingival groove fluid at the implant-abutment interface. Methods: Twenty-four (10 men and 14 women) patients referred to the Faculty of Dentistry for implant treatment, who met the inclusion criteria, were examined. Four different materials were used in each implant, including 2% chlorhexidine, 3% tetracycline, saliva, and a dry medium. Each test material was placed inside the implant screw during the anchorage session, and the healing screw was closed. Patients were then sampled in three implantation sessions and one month after prosthesis delivery. Interstitial fluid groove was used for sampling after cleaning the mouth (half an hour after three minutes of thorough brushing). The data were analyzed with SPSS 20 using ANOVA and relevant post hoc tests. Results: There was a significant difference in the mean IL-6 and IL-1ß levels between the four materials (P<0.05). IL-6ß levels were similar in tetracycline and chlorhexidine but significantly higher than in saliva and the dry environment (P<0.05). IL-6 and IL-1ß levels in the saliva were significantly higher than in the dry environment (P<0.05). Conclusion: The use of tetracycline at the junction of implant and abutment reduces the inflammatory cytokines IL-6 and IL-1ß.

Occurrence and severity of spontaneous exposure of cover screw after dental implant placement.

Background: Perforation of the soft tissues overlying the dental implant, resulting in early and spontaneous exposure of cover screws between stages I and II of the two-staged implant placement procedure, is a common problem that can disrupt the primary repair and osseointegration process. The present study aimed to investigate the prevalence of spontaneous exposure of cover screws in dental implants and identify the related risk factors. Methods: The present retrospective, descriptive-analytical study enrolled 40 patients with 182 dental implants in the second stage of the implant placement procedure. Data on patient-related and implant-related classified variables were collected, and all the samples were examined for cover screw exposure based on the classification by Tal. First, the overall prevalence of cover screw exposure was calculated. Then, statistical analysis was performed using SPSS 24 to investigate the effect of different variables on this exposure. The chi-squared test was used at the bivariate level, while the logistic regression was used at the multivariate level. Results: Of 40 participants with 182 implants, 17 implants (9.3%) in 9 patients (22.5%) became exposed to the oral cavity. In terms of severity, Class I exposure was the most common with seven implants. Moreover, Class III was the least common with only one implant. Using the logistic regression analysis, we found significant relationships between the dental implant exposure and the variables of overlying mucosal thickness (OR=24.7, P≤0.001), the duration between tooth extraction and implant placement (OR=9.6, P=0.005), and implant location in the jaw (OR=3.8, P=0.033). Moreover, exposure was more common in the maxillary premolar area (22.5%) than in other locations. Also, there was a significant relationship between implant exposure and lateral augmentation (OR=0.20, P=0.044), indicating the higher risk of exposure in implants with lateral augmentation than those without augmentation. Conclusion: Despite the limitations of this retrospective study, its results showed that three factors, including the overlying mucosal thickness of <2 mm, implant placement in fresh extraction sockets, and maxillary implants, especially at the location of maxillary premolars, were strong predictors of spontaneous implant exposure.

Therapeutic benefits of rutin and its nanoformulations.

BACKGROUND: Rutin as a natural flavonoid compound has revealed an extensive range of therapeutic potentials. PURPOSE: The current paper is focused on the numerous studies on rutin nanoformulations regarding its broad spectrum of therapeutic potentials. STUDY AND METHODS: A review was conducted in electronic databases (PubMed) to identify relevant published literature in English. No restrictions on publication date were imposed. RESULTS: The literature search provided 7,078 results for rutin. Among them, 25 papers were related to the potential biological activities of rutin nanoformulations. Polymeric nanoparticles were the most studied nanoformulations for rutin (14 titles) and lipid nanoparticles (5 titles) were in second place. The reviewed literature showed that rutin has been used as an antimicrobial, antifungal, and anti-allergic agent. Improving the bioavailability of rutin using novel drug-delivery methods will help the investigators to use its useful effects in the treatment of various chronic human diseases. CONCLUSION: It can be concluded that the preparation of rutin nanomaterials for the various therapeutic objects confirmed the enhanced aqueous solubility as well as enhanced efficacy compared to conventional delivery of rutin. However, more investigations should be conducted to confirm the improved bioavailability of the rutin nanoformulations.

Antibacterial effect of nanocurcumin inside the implant fixture: An in vitro study.

OBJECTIVES: Infections after implant placement are the main reasons for the failure of implant treatments. The present study aimed to evaluate the antibacterial effects of nanocurcumin inside the implant fixture against Escherichia coli, Staphylococcus aureus, and Enterococcus faecalis. MATERIALS AND METHODS: Twenty seven implants were classified in three groups for testing the antibacterial effect of nanocurcumin, chlorhexidine (as negative control), and distilled water (as negative control). Each group was then divided into three subgroups to study the effect of the applied torque on the antimicrobial effect of nanocurcumin. All implant abutment assemblies were submerged in bacteria suspension and were incubated at 37°C for 24 hours. The contents of each implant were removed to count the colony of bacteria on the surface of plates containing nutrient agar. RESULTS: Results indicated that the inhibitory rate of bacteria by nanocurcumin was above 99% in all bacteria. Besides, by increasing the amount of applied torque from 10 to 35 N.cm, the CFU of bacteria in exposure to nanocurcumin significantly were decreased (p-value < 0.01). CONCLUSION: The results of this study revealed that nanocurcumin can be used inside the implant fixture in order to use antimicrobial effects and further stabilization and success of the implant.

Anti-microbial activity of curcumin nanoformulations: New trends and future perspectives.

Curcumin has been used in numerous anti-microbial research because of its low side effects and extensive traditional applications. Despite having a wide range of effects, the intrinsic physicochemical characteristics such as low bioavailability, poor water solubility, photodegradation, chemical instability, short half-life and fast metabolism of curcumin derivatives limit their pharmaceutical importance. To overcome these drawbacks and improve the therapeutic ability of curcuminoids, novel approaches have been attempted recently. Nanoparticulate drug delivery systems can increase the efficiency of curcumin in several diseases, especially infectious diseases. These innovative strategies include polymeric nanoparticles, hydrogels, nanoemulsion, nanocomposite, nanofibers, liposome, nanostructured lipid carriers (NLCs), polymeric micelles, quantum dots, polymeric blend films and nanomaterial-based combination of curcumin with other anti-bacterial agents. Integration of curcumin in these delivery systems has displayed to improve their solubility, bioavailability, transmembrane permeability, prolong plasma half-life, long-term stability, target-specific delivery and upgraded the therapeutic effects. In this review paper, a range of in vitro and in vivo studies have been critically discussed to explore the therapeutic viability and pharmaceutical significance of the nano-formulated delivery systems to elevate the anti-bacterial activities of curcumin and its derivatives.

Active tactile sensibility of three-unit implant-supported FPDs versus natural dentition.

BACKGROUND: Splinting of the implants might improve the active tactile sensibility (ATS) of the pontic area due to cumulative effect of Osseo perception of two retainers; on the other hand, due to the lack of any supporting implant in the axis of occlusal force for the pontic area, ATS might be lower for this portion of FPDs. we evaluated the active tactile sensibility of natural teeth and three-unit implant-supported FPDs. MATERIAL AND METHODS: The ATS of posterior 3-unit implant-supported FPD and contralateral teeth was measured in 50 patients, in a random order blinded to patients and assessor, carried out at two sessions. Based on the experimental range of 0 to 70 um, the sigmoid shape of psychometric curve was estimated to locate the 50% values as the ATS thresholds for each tooth or implant. Data were analyzed using unpaired t-tests. RESULTS: The ATS of the teeth and implants differed significantly and compared to teeth, implants exhibited significantly higher ATS thresholds in all the groups. The results of independent t-test showed the highest difference in the means of ATS between the pontic and the first molar tooth. Based on the equivalence testing approach, the 95% CIs indicated that the differences were clinically significant only in the Pontic/First Molar group. CONCLUSIONS: In multi-unit implant-supported prostheses the tactile perception of the prosthesis that are placed on fixtures is similar to the natural teeth. In pontic areas there are significant statistical and clinical differences, with much lower tactile sensibility in pontics compared to the natural teeth. Key words:Active tactile sensibility, dental implants, interdental perception, osseoperception.

Compatibility of Clinical and Histopathological Diagnosis of Oral Lesions in Iranian Patients

Objective: To determine compatibility between clinical diagnosis and the pathological reports of biopsies from oral lesions. Material and Methods: In this descriptive study, 1146 clinical files of patients referring to Tabriz Faculty of Dentistry from 2004 to 2016 were retrieved and evaluated. The kappa coefficient was calculated for each file for compatibility of clinical and pathological diagnosis. Results: In relation to clinical (40.2%) and pathological (39.2%) diagnosis, irritational lesions of soft tissues exhibited the highest frequency. In 72.3% of cases, the clinical and pathological diagnosis were compatible and in 27.7% of cases these diagnosis were not compatible. The highest compatibility rates were detected for irritational lesions of soft tissues (81.5%) and mucocutaneous lesions (76.9%). There was no compatibility for osseous malignant tumors, inflammatory tissues, granulation tissues, metastatic lesions and hematologic disorders. Conclusion: Approximately one-third of clinical and histopathological diagnosis were not compatible. Therefore, to reach a correct diagnosis, the clinical, radiographic and histopathological views should be evaluated simultaneously.

Investigating the effect of abutment-implant connection type on abutment screw loosening in a dental implant system using finite element methods.

Background. The most common problem associated with dental implants is the abutment screw loosening. This research aimed to investigate the effect of the type of connection on screw loosening, using a finite element method (FEM). Methods. Periosave system and different types of the implant-abutment connection were used for modeling. After being measured, CAD files were modeled using CATIA software and imported to the ANSYS analysis software, and the model was loaded. Results. A force of 100 N was applied at 0.1 second, and no force was applied at 0.42 second. The screw head deformation at 0.1 and 0.42 seconds was 8 and 3.8 µm, and 7.6 and 2.8 µm at morse taper and octagon dental implant connections, respectively. The displacement rate of the internal surface of the abutment at 0.1 and 0.42 seconds was 10.7 and 8.4 µm, and 5.7 and 5.6 µm in the octagon and morse taper dental implant connections, respectively. The displacement of the implant suprastructure-abutment interface from the screw head at 0.1 and 0.42 seconds was 9 and 7 µm, and 7 and 6 µm in the morse taper and octagon dental implant connections, respectively. At intervals of 0 to 0.1 seconds and 0.6 to 0.8 seconds, the octagon connection was separated at the maximum screw head displacement and the internal part of the abutment, but the morse taper connection did not exhibit any separation. In the above time intervals, the results were similar to the maximum state in case of the minimum displacement of the screw head and the internal part of the abutment. Conclusion. Screw loosening is less likely to occur in the morse hex connection compared to the octagon connection due to the lack of separation of the screw from the internal surface of the abutment.

Comparison of edema and ecchymosis in rhinoplasty candidates after lateral nasal osteotomy using piezosurgery and external osteotomy.

Rhinoplasty is done with external and endonasal methods. One of the main stages of rhinoplasty in both external and endonasal methods is the lateral nasal osteotomy. Lateral nasal osteotomy is the main cause of edema and ecchymosis after rhinoplasty, which is annoying and unpleasant for patients. Piezosurgery is a new method that uses electronic-ultrasonic waves to perform nasal osteotomies. The aim of this study was to compare of edema and ecchymosis after lateral nasal osteotomy using piezosurgery with external osteotomy in rhinoplasty candidates. In this clinical trial, 66 experimental patients for rhinoplasty surgery were selected from Imam Reza hospital in Tabriz, Iran. After examination, the patients were randomly divided into two groups. One group of patients had lateral nasal osteotomy by using the piezosurgery technique, and the other group had a lateral osteotomy with the conventional method of external subcutaneous. On the third and 7 days after the operation, the level of edema and ecchymosis in the patients were examined as per the Gökalan questionnaire (adopted by Yucel) by two persons who were not aware of the goals of the study, and then, they evaluated and scored the questionnaire. The obtained data were analyzed by the SPSS 19 software. The highest level of edema and ecchymosis was observed 3 days after surgery in both groups. Meanwhile, the findings revealed a significant difference between the two groups in the amount of edema and ecchymosis on day 3 after surgery. Furthermore on day 7, the amount of edema and ecchymosis compared to that of the 3rd day was statistically significant for both groups. In general, in all studied groups, edema, and ecchymosis decreased in 7 days compared to 3 days and also piezosurgery is more promising and effective than osteotomy.

Effect of Consecutive Removal and Placement of Abutments during Prosthetic Procedures on an Increase in Proinflammatory Cytokine Levels around Dental Implants

Objective: To evaluate the effect of repeated removal and placement of abutments during prosthetic stages on increasing proinflammatory cytokine levels around dental implants. Material and Methods: All the patients with dental implants, referring to the prosthodontics private office during a 3-month period, were examined in relation to the health of the implants and included in the present study based on inclusion criteria; the patients had a multi-unit abutment on one side of the jaw and a conventional healing abutment on the implant on the other side of the jaw. Samples of gingival crevicular fluid were taken from all the eligible subjects for immunological analyses. The samples were taken from the sulcus around each implant in each subject. The samples were sent to the immunology laboratory for determination of IL-6 and IL-1ß proinflammatory cytokines with the use of an ELISA kit. Data were analyzed with SPSS 16 and Descriptive statistics and T-test was used. Statistical significance was set at p<0.05. Results: The results showed that the mean concentrations of IL-1ß and IL-6 in the group with multi-unit abutment were less than those in the conventional abutment group. In addition, comparison of the means of IL-6 and IL-1ß concentrations showed that in both groups the concentration of IL-6 was higher than that of IL-1ß. Conclusion: The use of multi-unit abutments resulted in less inflammation compared to the use of conventional two-segment abutments, which require repeated removal and placement during the prosthetic stage.

Comparison of Proinflammatory Cytokine Levels in Gingival Crevicular Fluid around Dental Implants with Ceramic and Titanium Abutments.

BACKGROUND: Considering the high success rate of osseoin-tegration, there is ever-increasing use of dental implants. The mechanisms and biologic response of peri-implant tissues are different depending on the biocompatibility of the implant material. The aim of this study was to compare the proinflammatory cytokine levels in the gingival crevicular fluid (GCF) around dental implants with ceramic and titanium abutments. MATERIALS AND METHODS: All the patients with dental implants referring to two private offices of two prosthodontists from June to August 2016 were examined in relation to implant health, and eligible subjects, based on inclusion criteria, were included in this study with a slit-mouth design. In this context, on one side titanium implants and, on the other side, ceramic implants were used. Samples were collected from the peri-implant sulcus in each patient and sent to the immunology laboratory for determination of interleukin (IL)-6 and IL-1ß proinflammatory cytokine levels using an enzyme-linked immunosorbent assay kit. Data were analyzed with Statistical Package for the Social Sciences version 16. Statistical significance was set at p < 0.05. RESULTS: The results showed lower levels of IL-1ß and IL-6 in the GCF around ceramic abutments compared with titanium implants. In addition, statistical comparison between IL-6 and IL-1ß levels showed higher levels of IL-6 around titanium and ceramic abutments compared with IL-1ß levels. CONCLUSION: Based on the results of this study, the human body immune response to ceramic abutments is much better than that to titanium implants. CLINICAL SIGNIFICANCE: Considering that proinflammatory cytokine levels in GCF around ceramic abutments are lower than titanium ones, ceramic abutments are preferred for clinical usage.