Impression Tray Research Articles

An in vitro Study to Assess the Positional Accuracy in Multiple Implants using Different Splinting Materials in Open-Tray Impression Technique

Context: Numerous implant techniques have been suggested in the literature to obtain an accurate master cast. One of those is to splint the impression copings; however, many controversies exist in type of splinting materials used. Aim: The aim of this study is to evaluate and compare the positional accuracy in multiple implants using different splinting materials in open-tray impression technique. Settings and Design: The study design involves an in vitro study. Materials and Methods: An acrylic resin model of a mandibular edentulous arch was used as a reference model in which four 3.75 mm × 10 mm implant analogs were placed and sequentially numbered as 1, 2, 3, and 4 from left to right. Open tray impression copings were attached to each of them and were then splinted by three different materials and divided into three Groups as Group I, Group II, and Group III splinted with pattern resin, composite resin, and titanium wire, respectively. Five implant level impressions were made from each group and poured in Type IV dental stone. The implant analogs were transferred to the casts and inter-implant distances were compared to the reference model using the Coordinate Measuring Machine. Statistical Analysis Used: One-way ANOVA test was used as a test of significance. Results: The present study revealed that all the three splinting materials can be used for the accurate reproduction of spatial relationship. There was no significant difference between the centroids of implant analogs 1 and 2, 1 and 3, 1 and 4, 2 and 3, 3 and 4, and 2 and 4 of reference model with the master models. Conclusion: Clinically acceptable accuracy in transferring the position of implants to the master cast could be obtained from all the three splinting materials used. However, splinting of impression copings with titanium wire showed greatest accuracy.

Infection control in impression making procedures in the dental clinics

Aim: This study aims at investigating the behavior, orientation, attitude and knowledge of dental practitioners towards the infection control in the impression making procedure. Materials and Methods: A questionnaire consisting of 10 questions was designed to assess the details of impression material used and its disinfection. The questionnaire was sent to the dental practitioners of 70 clinics. Results: Out of 110 participants 91.81% sterilized their impression trays before making impressions. 94.54% Practitioners poured their impressions in their clinic.93.63% practitioners believed in rinsing the impressions before dispatching them to laboratory.52.27% practitioners disinfected their impressions prior to sending the impressions to the laboratory.79.09% participants were sure that their laboratory person is disinfecting the impressions before proceeding. 71.81% practitioners believed that immersion of impressions in the disinfectant solution impairs the dimensional stability of impression material.89.09% believed that cross infection can lead to the life threatening diseases. 93.63% participants used Alginate as the primary impression material. 48.18% practitioners believed in disinfecting the impressions under tap water, 16.36% believed in disinfection using the spray and 9.09% disinfected by immersing impressions in the disinfectant. Only 20.90% participants used the autoclavable special impression material for at risk patients. Conclusion: Still there is lack of knowledge regarding disinfection of the impression and maintaining infection control during the impression making procedure. So an effort should be made to impart thorough knowledge about proper disinfection in the undergraduate and postgraduate curriculum. Keywords: Disinfection, Dental practitioners, Impressions, Survey.

Dental Impression Tray Selection From Maxillary Arch Images Using Multi-Feature Fusion and Ensemble Classifier

Dental impression tray is frequently used in dentistry to record the patient’s oral structure for clinical oral diagnosis and treatment planning. Manual procedure of taking impressions is costly, time-consuming, and additionally, no research has been done on selecting dental impression tray from dental arch images using computer vision in real-life scenarios. In this spirit, an intelligent model is proposed based on computer vision and machine learning to select appropriate dental impression trays from maxillary arch images. A dataset of 52 patients’ maxillary arch images have been acquired and various sets of features such as colors, textures, and shapes of the images were extracted to better characterize the maxillary arch images. Considering the importance of the features in describing the maxillary arch object and to improve the classification performance, a method based on multi-feature fusion with ensemble classifier is proposed. Besides, the performance of a deep learning based multilayer perceptron neural network is also investigated. The proposed multi-feature fusion with ensemble classifier attained 92.31% precision, 91.75% recall, 91.75% accuracy, respectively, on the dataset, which clearly establishes the feasibility of the proposed model. An illustration of a real-life application of the proposed model is also provided.

Effect of digital workflow on the marginal fit of long-span implant-supported bars for kennedy ii class removable prostheses in vitro

Introduction The production procedures, including impressions, introduce errors affecting the passivity of fit. A completely digital workflow is possible nowadays because of the intraoral scanners (IOS). This study aimed to evaluate the effect of the impression technique (conventional versus digital) and the screw tightening sequence on the marginal discrepancy (MD) of implant-supported bars. Methodology This laboratory study was conducted on a simulated Kennedy class II edentulous maxilla with three parallel implants in the edentulous quartile. The closed tray technique with a-silicon (CTM) and the intraoral scanning with the I-Tero™ system (IOS) were compared and three bars were manufactured from each technique. Depending on the screw tightening sequence (A11 and A17) 4 groups were created with 6 samples each. The MD was examined implementing 24 negative replicas, which were sectioned and studied under a stereomicroscope. The Horizontal Discrepancy (BHD), Vertical Discrepancy (BVD) and Conical Discrepancy (BCD) of the bar were calculated on the means of the measurements of the horizontal, the vertical and the conical MD respectively. The descriptive statistics, normality tests, one-way ANOVA (a=.05) and post-hoc Tukey’s tests were run and the graphs were draw with SPSS. Results There was a significant effect (P<.05) of the impression technique combined with the screw tightening sequence on all variables. The post-hoc Tukey’s tests revealed significant differences between all groups except from those of the same impression technique only for the BHD (P<.05). Conclusion In this study all groups resulted in marginal discrepancies. The closed tray impression technique gave better results.

Comparison of the accuracy of intraoral digital impression system and conventional impression techniques for multiple implants in the full-arch edentulous mandible

BackgroundSeveral impression techniques, especially in combination with computer-aided design and computer-aided manufacturing (CAD/CAM), are used in increasing the accuracy of dental implantology and decreasing patient discomfort. The study was designed to examine the accuracy of the digital impression (DI) of multiple implants with an intraoral scanner (IOS) and compared with that of a conventional impression (CI). Material and MethodsFour dental implants were placed in teeth area #33, #36, #43 and 46# of the mandibular full-arch model. The implanted model was replicated by IOS and CI after fitting of scannable abutments over the implant screws. Then, a small hole was made on the scan region (as a reference point). Two types of CI techniques were used; dual-phase (DP) and monophase (MP). Stone casts were produced through a conventional close tray impression technique using die stone. The casts were scanned with a laboratory scanner. DI was attained by scanning the implanted model with the IOS. The control sample was accomplished by scanning the implanted model directly with a laboratory scanner. Dimensional accuracy was calculated by measuring the distances between the reference points of four measuring parameters as follows; A-B, B-C, C-D, and A-D using CAD software. ResultsThe mean values and standard deviation between the four parameters of different impression techniques (CI and DI) and the control group showed convergent value. One-way ANOVA test showed all CI techniques, except IOS, showed a significant differences from the control group. ConclusionsCompared with CI, the IOS was more accurate because no differences were observed between its measurements and those of the control model. CI is simple and reduces patient discomfort when used in fabricating multiple implants and allowing communication with dental technicians. Key words:Dimension accuracy, conventional impressions, digital impressions, multiple implants.

Study the Effects of Bilateral Balanced Occlusion and Canine Guidance on Masseter and Temporalis Muscle Activity in Implant-Retained Overdentures Constructed with Open and Closed Tray Impression

The aim of the study was to investigate the effects of balanced occlusion and canine guidance on masseter muscle activity in implant- retained overdentures constructed with open and closed tray impression. Material and methods: For the current study Twelve completely edentulous patients were selected from the Outpatient Clinic of Removable Prosthodontic Department, Faculty of Dental Medicine, Al Azhar University (Assiut branch) according to special inclusion and exclusion criteria. All procedures were explained to all the patients and informed consent was assigned by each patient before the commencement of the investigation. All patients were divided into two groups; with the first group open tray impression techniques was used. While the second group used close tray impression techniques.For each group two dentures were constructed; the first denture was constructed with bilateral balanced occlusion, while the second denture was constructed with canine guidance.Conclusion: Successful implant overdenture has a positive effect on the masticatory efficiency regardless of the type of impression used. Masticatory efficiency improved with closed tray impression method together with bilateral balance occlusion had the best masticatory efficiency during chewing soft food or hard food than any other impression method (close-open tray impression) with any other occlusion (bilateral balance-canine guided occlusion) during chewing soft or hard food.

The Effect of Adhesive Material and Surface Roughness on the Tensile Bond Strength between Some Elastomeric Impression Materials and Cold Cure Acrylic

: The detachment of impression materials from impression tray is considered as an important problem which is difficult to be detected clinically. Several attempts were used to handle this problem, as roughening the surface of the tray, perforating it, or by the use of adhesive solutions which are recommended to be used by manufacturers. Objectives: To determine the tensile bond strength of two elastomeric impression materials; polysulphide and polyether to cold-cure acrylic resin disks with or without tray adhesive application at different drying and surface treatment. Material and Methods: Eighty specimens prepared consisted of two disks with impression material sandwiched between, then divided into two groups; 40 specimens for each type of impression. The “PD” hold adhesive material was applied on the acrylic surfaces which were smooth and rough. The adhesive was allowed to dry for 2, 5, and 10 minutes before the application of impression materials. To determine tensile bond strength at the interface between the adhesive-acrylic, and the adhesive-impression materials, a universal Instron testing machine was used. Results: Polyether impression material showed higher tensile bond strength to cold-cure acrylic than polysulphide impression material, without adhesive application. However, after adhesive application, the bond strength to polyether decreased, while for polysulphide increased significantly. Roughening the acrylic surface significantly increased the bond strength for both impression materials with or without adhesive application. Also, increasing the drying time from 2 up to 10 minutes significantly increased the bond strength for both impression materials, and smooth and rough acrylic surfaces. Conclusions: Polyether impression showed higher bond strength to cold-cure acrylic than polysulphide impression, without adhesive application.

Cast metal sprue as an alternative to dental floss for splinting open tray impression copings for complete-arch implant impressions

Conventional implant impressions can be made with an open tray (pick-up) or closed tray (transfer) technique,1,2 with the open tray technique recommended for complete-arch implant impression because of its greater accuracy.3 However, stabilization of the impression copings is essential to prevent micromovement when it is detached from the implant fixture or during placement of the implant laboratory analog.4 Rigid impression copings are essential for the accurate transfer of their 3D position to the definitive cast.

Three-Dimensional Accuracy of Conventional Versus Digital Complete Arch Implant Impressions.

The accuracy of digital impressions is still controversial for complete arch implant cases. The aim of this study is to compare the accuracy of different intraoral scanners with the conventional technique in terms of trueness and precision in a complete arch implant model. Eight implants were inserted asymmetrically in a polyurethane edentulous mandibular model with different angulations. A 3-dimensional (3D) reference model was obtained by scanning this polyurethane model with an optical scanner. First, digital impressions were made by using 3 different intraoral scanners: Carestream 3500 (DC), Cerec Omnicam (DO) and 3Shape Trios 3 (DT). Subsequently, a nonsplinted open tray impression technique was used for conventional impression group (C) and then the master casts were digitalized with a lab scanner. Each 10 STL files belonging to 4 different impression groups were imported to a reverse engineering program, to measure distance and angle deviations from the reference model. All statistical analyses were performed after taking absolute values of the data. After comparing the impression groups with one-way ANOVA, the trueness and precision values were analyzed by Tukey post hoc test and 0.05 was used as the level of significance. The mean trueness of distance was 123.06 ± 89.83 µm for DC, 229.72 ± 121.34 µm for DO, 209.75± 47.07 µm for DT, and 345.32 ± 75.12 µm for C group (p < 0.0001). While DC showed significantly lower deviation compared to DO and C, no significant difference was found between DC and DT. C showed the highest distance deviation significantly in all groups; and no significant difference was found between DO and DT groups. In angle measurements; the trueness was 0.26° ± 0.07° for DC, 0.53° ± 0.42° for DO, 0.33° ± 0.30° for DT, and 0.74° ± 0.65° for C group. There was no significant difference between the groups in terms of angular trueness (p = 0.074). In terms of the precision for distance, the results of DC 80.43 ± 29.69µm, DO 94.06 ± 69.96 µm, DT 35.55 ± 28.46 µm and C 66.97 ± 36.69 µm were determined (p = 0.036). The significant difference was found only between DT and DO among all groups. Finally, angular precision was determined to be 0.19° ± 0.11° for DC, 0.30° ± 0.28° for DO, 0.22° ± 0.19° for DT, and 0.50° ± 0.38° for Group C. No significant difference was found between the groups, in terms of angular precision (p = 0.053). All digital impression groups yielded superior data compared to conventional technique in terms of trueness. DC formed the impression group with the highest trueness in both distance and angular measurements. The results of this in vitro study suggest the use of intraoral scanners compared to the conventional impression techniques in complete arch implant cases with high angulations.

Tensile bond strength of polyvinyl siloxane impression material to auto-polymerizing custom tray using different tray adhesives: A comparative study

Aim: In clinical practice, a material called adhesive is frequently applied over the impression tray to adhere impression materials to it. This prevents dislodgement of material which causes distortion of the impression made. This study aimed to compare the tensile bond strengths of polyvinyl siloxane impression material to auto-polymerizing custom tray using different tray adhesives. Materials and Methods: A total of sixty uniform blocks of auto-polymerizing custom tray specimens were built using a mould made of stainless steel. They were coated with one of the four adhesives (manufactured by 3M ESPE, Coltene-Whaledent, Ivoclar Vivadent, GC) and the force at which separation failure occurred was measured using Universal testing machine. Result: The results found that any of the commonly used adhesives (manufactured by 3M ESPE, Coltene-Whaledent, Ivoclar Vivadent, GC) can be used for application on auto-polymerizing custom trays before polyvinyl siloxane is added to the tray, however, tray adhesive by Coltene-Whaledent (Adhesive) was found to have the best bond strength followed by tray adhesive from GC (Vps Universal Tray Adhesive). Conclusion: Tray adhesive by Coltene-Whaledent (Adhesive) has the best bond strength followed by tray adhesive from GC (Vps Universal Tray Adhesive). Keywords: Adhesives, Dental Bonding, Dental Impression Materials, Silicone Elastomers, Stress, Mechanical.

Types of Impression Trays and its Effect on Impression Materials Choosing.

A dental impression is a negative print of teeth and soft tissues in the mouth which can produce a positive copy model. It can be made by putting a suitable material in a stock or custom dental impression tray which is designed to fit as possible over the dental arches. Figure 1 shows a dental impression made using alginate impression material [1].

Disposable plastic trays and their effect on polyether and vinyl polysiloxane impression accuracy\u2014an in vitro study

ObjectivesTo evaluate the dimensional accuracy of impressions taken by use of disposable stock plastic trays and to compare performance with that of metal trays.Materials and methodsFrom a metallic model incorporating three precision balls and three abutment teeth, one-step dual-phase polyether (PE) and vinyl polysiloxane (VPS) impressions were taken using either metal or disposable plastic trays (n = 10 for each of the resulting four test groups). Respective plaster cast scans were aligned with the reference dataset to evaluate global (distance and angle deviations) and local (trueness and precision) accuracy. Analyses of variance (ANOVA) were conducted to determine group differences.ResultsFor all impression tray and material combinations, global accuracy was good (mean distance changes < 100 μm) with greatest deviations being observed for distances exceeding one quadrant of the dental arch. In general, distances measured in the plaster casts were too short. Only VPS impressions with plastic trays showed a different behavior with a large percentage of cross-arch distances exceeding the reference value. Mean local accuracy ranged between 6 and 14 μm (trueness), and 6 and 16 μm (precision). On abutment tooth level, metal trays were associated with a significantly better precision (p = 0.015).ConclusionsThe observed distortions of the studied impression trays and materials are small and should enable satisfying clinical impression-taking.Clinical relevanceCleaning and processing of metal trays before re-use are time-consuming. Especially for patients’ management with single crowns and small fixed dental prostheses, disposable plastic trays can be a viable and cost-effective alternative.

Day to Day Use of Disinfectant Methods for Different Impression Materials among Dental Practitioners

One of the major problems which most dental professionals face is cross contamination and cross infection. During the fabrication of dental prosthesis, special care should be taken for every step, especially impressions as they are one of the main concern. This is because impressions are one of the most known to be the main source of infection for any potentially infectious material . To check the practice of disinfection level among the dental practitioners, a questionnaire containing 15 questions was prepared. This survey was carried between the month of June 2019 to March 2020 among the dental practitioners living in Chennai, Tamil Nadu, India. This survey was carried under an online platform where the participants responded to their answers. Based on their responses, the result was tabulated. We got a result of about 64% practitioners practicing protocol to disinfect impressions 65% use alginate to take impressions. 44% use 2% glutaraldehyde to disinfect impressions. 46% prefer spraying disinfectant over impression tray. Based on much research, it was reported that dental technicians were suffering from infections in hand restoratory systems, so on humanitarian basis we dentists can take better measures ourselves in avoiding cross contamination to fellow dental technicians by following proper and simple methods for disinfection of impressions before sending them to dental laboratories. To conclude awareness workshops, programs must be organised to create awareness among dentists to present cross infections.

Effect of impression holding time and tray removal speed on the dimensional accuracy of impressions for artificial abutment tooth inclined.

Oral scanners allow dental impressions to be taken in a short time without the use of an impression material. However, it has been noted that high impression accuracy cannot be obtained in cases where the abutment is inclined or in cases where the span is long. Consequently, in daily clinical practice, impressions are often created using silicone impression material. When taking an impression using silicone impression material, the curing time or the removal time of the impression material are often based on the intuition of the dental staff. This study investigated the effects of impression holding time and impression tray removal speed on the dimensional accuracy of impressions. A specimen with an abutment inclined 30° to the removal direction of an impression was prepared. Four types of silicone rubber impression materials were used. Impressions were taken with two levels of holding time and two levels of removal speed using an autograph. The diameter of stone models was measured at 3, 6, and 9mm from the baseline of each. The height of the inclined and opposite sides was also measured. Two-way analysis of variance was used to analyze data regarding the assessment of the effects of holding time and tray removal speed. The reproducibility of the impressions was affected by the volume of undercut caused by the inclined abutment. For a large undercut, longer holding times and faster tray removal speeds are recommended to reduce the deformation of silicone rubber impressions.

EVALUATION OF ACCURACY OF TWO DIFFERENT IMPRESSION MATERIALS AND THREE DIFFERENT IMPRESSION TECHNIQUES ON THE VERTICAL MISFIT OF A THREE UNIT IMPLANT SUPPORTED FIXED DENTURE PROSTHESES

&#x0D; &#x0D; &#x0D; AIM: The aim of the study is to evaluate the accuracy of two different impression materials and three different impression techniques on the vertical misfit of a three-unit implant supported fixed denture prostheses.Materials and Methods: A total of 60 casts were fabricated for the present study with a closed tray, open tray and open tray splinted abutment impression technique. Two different commercially available impression materials were used - polyether and addition silicone. Both the materials were used for all the above impression techniques.Results: Accordingtotheresultderivedfromthisstudypolyethershowedleastmarginalgap.On the other hand on the basis of impression techniques open tray impression with splinted transfer coping also exhibited a minimum marginal gap.Conclusion: 1. Higher marginal accuracy was found in impressions made by polyether compared to polyvinyl siloxane. 2. Open tray splinted technique exhibited a minimum marginal gap when used with polyether as impression material compared to open tray non splinted technique and closed tray technique.&#x0D; &#x0D; &#x0D;

COMPARATIVE CHARACTERISTICS OF TRANSFERS SPLINTING TECHNIQUES IN THE PROCESS OF TAKING ONE-STAGE DOUBLE-LAYERED DENTAL IMPRESSIONS BY MEANS OF OPEN TRAY IMPRESSION TECHNIQUE

Abstract. According to conclusions of ITI World Congress (2018), the accuracy of the dental impression determines the quality of the working model and, consequently, the fixation of the prosthetic restorations at the final stage. Inaccurate dental impression will inevitably lead to technical and biological complications (Wolfart S., 2016). According to Lee and co-authors (2019), the accuracy of the dental impression is influenced by the chosen method, namely closed or open tray, the presence or absence of transfers splinting and the choice of impression material type.&#x0D; The most accurate impression has been proved to be an impression taken with the use of an open tray impression technique, by means of polyether impression material with preliminary transfers splinting using internally interfaced implant system.&#x0D; The objective of the research was to evaluate the quality of implants placement transferring to the model by comparative analysis of different methods of clinical transfers splinting in order to take impressions using an open tray impression technique.&#x0D; Twelve clinical situations were studied. Four groups were formed according to the method of transfer splinting. Each group included 3 clinical cases. Impressions were taken with the use of an open tray impression technique in all clinical cases with preliminary custom-made trays with holes in the implants projections.&#x0D; A grading scale was created when assessing the quality of transfer splinting as a key factor in the accuracy of implant placement transferring.&#x0D; Each of the groups received from 1 to 4 points where 1 point was the worst result according to this criterion and 4 points meant the best one. Among the criteria for splinting quality evaluation, 1-3 criteria were considered to be subjective, criterion 4 was considered to be objective. Therefore, criterion 4 received coefficient ×2 in order to increase the objectivity of the results evaluation.&#x0D; There were 4 criteria:&#x0D; &#x0D; The simplicity of the technique and the time spent splinting.&#x0D; The cost of the technique.&#x0D; Passivity when fixing the bridge prosthetic restoration after manufacturing.&#x0D; Radiologically measured distance between the centers of implant analogues on the model relative to each other after an impression taking by means of different splinting techniques and deviation of the value from the position of the centers of implants heads tops after osseointegration according to CT scan.&#x0D; &#x0D; Analyzing the results of the research, splinting techniques were ranked according to the obtained points.&#x0D; Research group 1 scored 6 points using dental floss and flowable compomer. A considerable amount of time was spent splinting with relatively inexpensive technology. The passivity of the fixation was the worst in comparison with other methods and the largest error was determined radiographically.&#x0D; Group 4 scoring 17 points was determined as the best of the chosen techniques. Despite the high cost of the chosen technique, prosthetic restorations made after transfers splinting by means of this technique had the highest fixation accuracy and the lowest deviation of the implants analogues on the model radiographically in comparison with the position of the implants in the upper alveolar ridge and lower alveolar ridge due to the cost of the material based on poly-vinyl siloxane.

Assessment of accuracy of open tray and closed tray dental implant impression techniques: A comparative study

Background: A dental impression is a negative imprint of an oral structure utilized to produce a positive replica of the structure that can be used as a permanent record or in the production process of a dental restoration. Hence; the present study was undertaken for assessing the accuracy of two different dental implant impression techniques. Materials & methods: For reference model, an edentulous mandibular cast with four implant analogues in the anterior region was used. For the present study, two different types of impression trays were used as follows: Closed custom tray, and Open custom tray. The impressions were allowed to set for 10 minutes under a standard load of 500 gm. All the impressions were poured using the same quantity of Type IV dental stone. The casts were subjected to measurement after 24 hours to simulate clinical situation. All the results were recorded in Microsoft excel sheet and were analysed by SPSS software.Results: Mean error obtained in closed custom tray technique was 0.028 while mean error obtained in open custom tray technique was 0.23. While analysing statistically, significant results were obtained. Conclusion: Better results are obtained when open custom trays were used.

An Alternative Impression Technique for Fabrication of Feeding Appliance for an Infant with Cleft Palate: A Clinical Report

Cleft lip and palate is the most common congenital defect of the orofacial region, which results in difficulty in feeding, deglutition, and speech. Before the surgical intervention, a feeding appliance is used to restore the palatal cleft and aid in feeding an infant. The impression procedure during the fabrication of a feeding appliance is a crucial step and selection of impression tray and impression material is a challenging task. This article attempts to briefly describe an alternative technique for making impressions in infants with cleft palate.

Accuracy of different impression techniques for multiple implants angulated to each other: An in vitro study

Aim and objective: To evaluate the accuracy of different impression techniques - namely the closed tray impression technique, the open tray non-splinted impression technique, the open tray splinted technique and an experimental technique for multiple implants placed at an angulation with each other. Materials and Methods: A master model was made of die stone which incorporated four implants having an internal hexagonal connection. The two terminal implants were placed at an angle of 20 degrees (lingually) whereas the two central implants were placed perpendicular to the cast. The samples were divided into four groups (Group I: Closed tray impression technique, Group II: Open tray impression technique non-splinted, Group III: Open tray impression technique splinted and Group IV: Experimental technique) based on the impression technique used. P-values were obtained using one-way analysis of variance (ANOVA) with Tukey’s correction for multiple group comparisons.Results: The P-value was greater than 0.05 (0.869) for Group III. Therefore, open tray splinted technique (Group III) was the most accurate impression technique when compared to the other techniques. On Inter - group comparisons it was noted that the values obtained by experimental technique were within close range of the values obtained by open tray splinted impression technique. Whereas, a comparison of Group I with Group III revealed 2 points of statistical significance (2 points of inaccuracy). Comparison of the Group II with Group III showed that all the points were statistically significant (all points were inaccurate). Conclusion: The open tray splinted impression technique provides best results for multiple implants placed at varying angulations. The experimental technique can be beneficial in areas of limited access, reduced mouth opening and exaggerated gag reflex.

DOES PRESTERILIZATION HAS ANY INFLUENCE ON CONSERVATIVE AND ENDODONTIC MATERIAL STERILITY, IMMEDIATELY AFTER UNPACKING AND POST EXPOSURE TO CLINICAL ENVIRONMENT FOR 15 DAYS - AN EX VIVO STUDY.

Background: Instruments used in the operative area are colonised by various microbial organisms during usage. Sterilization is an important prerequisite to avoid cross contamination.&#x0D; Purpose of the study: The purpose of this study was to evaluate whether presterilization has any influence on conservative and endodontic material sterility, immediately after unpacking and post exposure to clinical environment for 15 days.&#x0D; Methods: Gutta percha cones, Rubber dam clamps, Impression trays, Dental burs (#245 bur, Access opening bur) were tested.Materials were randomly sampled at 2 time points (t0, at package opening; t1, at 15days) during their clinical usage. Vortexing, centrifuging, streak and inoculation was done. Colony formation under aerobic conditions was observed on media before and after presterilization.&#x0D; Statistical analysis: Wilcoxon matched pairs test was done for comparison of data before and after pre sterilization with status of aerobic organisms at to (immediately after opening) and t1 (during clinical usage).&#x0D; Conclusion: Presterilization effectively eliminates cross contamination of various aerobic microorganisms in conservative and endodontic material immediately unpacked and post exposure to clinical environment for 15 days.