Evaluation of the wear characteristics of three different materials used for provisional implant supported restorations

Aswana Jaiprakash,Jayakrishnakumar Sampathkumar,Chitrashankar Krishnan,Hariharan Ramasubramanian,Hariharan Ramakrishnan,Rahmath Shameem,Nagarasampatti Sivaprakasam Azhagarasan 대한치과이식임플란트학회 2021 The Korean Academy of Implant Dentistry Vol.40 No.3

Purpose: This study was conducted to comparatively evaluate the wear resistance of three different materials used for provisional implant supported restorations. Materials and Methods: Thirty natural mandibular first premolar teeth were considered as antagonist teeth specimens. Ten samples each of milled Polymethylmethacrylate (milled PMMA, GROUP I), milled Polyetheretherketone (milled PEEK, GROUP II) and indirect composite resin (SR ADORO, GROUP III) were designated as disc samples. The samples were subjected to wear test in a pin-on- disc machine. Surface roughness wear rate coefficient of friction and volume loss were measured after wear testing. The results were analyzed using paired ‘t test, Analysis of variance, and Post- hoc Tukey s HSD analysis. Scanning electron microscopic analysis was done for one representative tested sample from each test group. Results: Mean surface roughness (Ra) values before and after wear test for GROUPS I, II and III were 0.827 μm, 6.021 μm, 0.473 μm, and 1.194 μm, 0.455μm and 1.407 μm respectively. Mean wear rates (mg/min) of GROUPS I, II & III were 0.000 ,0.010 and 0.011 respectively. Mean coefficients of friction (μ) of Groups I, II & III were 0.979, 0.864 and 0.840 respectively. Mean volume loss (mm3) of GROUPS I, II & III were 6.709, 7.726 and 5.244 respectively. Scanning electron microscopic analysis revealed prominently roughened surface for GROUP I, moderately roughened surface for GROUP III and smoother surface for GROUP II. Milled Polymethylmethacrylate exhibited significantly higher surface roughness both before and after wear test as compared to both milled Polyetheretherketone and composite materials, which was corroborated by surface profilometry and Scanning electron microscopic analysis. Conclusions: Milled Polymethylmethacrylate showed significantly higher wear as compared to other two materials indicative of least wear resistance among the test materials. Milled Polyetheretherketone exhibited a marginally smoother surface compared to composite. Milled Polyetheretherketone and composite showed marginal differences in wear resistance which was statistically insignificant, indicative of similar wear resistance of these two test materials.

Evaluation of the effect of EDTA on the antifungal properties, flexural strength, and colour stability of heat polymerised PMMA resin for implant overdentures

Yasmin Fathima,Jayakrishnakumar Sampathkumar,Hariharan Ramakrishnan,Nagarasampatti Sivaprakasam Azhagarasan 대한치과이식임플란트학회 2022 The Korean Academy of Implant Dentistry Vol.41 No.2

Purpose: To evaluate the effect of ethylenediaminetetraacetic acid (EDTA) on the antifungal properties, flexural strength, and color stability of heat polymerized polymethyl methacrylate (PMMA) denture base resin. Materials and Methods: Eighty PMMA heat cure denture base resin test samples of the following sizes were fabricated: 10×1 mm (disc), 64×10×3.3 mm (strip), and 50×0.5±0.05 mm (disc) with or without EDTA. The PMMA heat cure denture base resin samples formed one group (GROUP I, n=40) and PMMA heat cure denture base resin samples incorporated with 8% EDTA were the second group (GROUP II, n=40). These were further subdivided according to the testing parameters as follows: Qualitative analysis of antifungal properties (GROUP I: 10 and GROUP II: 10), quantitative analysis of antifungal properties (GROUP I: 10, GROUP II: 10), flexural strength, and colour stability, 10 samples each for both groups and properties. The antifungal properties of GROUP I and GROUP II were evaluated qualitatively and quantitatively by measuring the zone of inhibition using the disc diffusion method and colony forming units (CFU), respectively. The flexural strength and color stability were evaluated using the three-point bend test and a spectrophotometer. The color difference (ΔE) was calculated. Results: The mean zone of inhibition for GROUP I and GROUP II samples was 0 mm and 9.2 mm, respectively. The mean CFU of GROUP I and GROUP II was 119.50×106 and 45×, respectively. The mean flexural strength of GROUP I and GROUP II samples was 145.43 MPa and 112.57 MPa. The colour difference between GROUP I and GROUP II samples ΔE was 2.89. Conclusions: PMMA heat polymerized denture base resin incorporated with EDTA exhibited antifungal properties and a minimum reduction in flexural strength, with a perceptible color difference. This modified PMMA resin is recommended for implant overdentures.

Evaluation of machining tolerance and vertical microgaps of biohpp peek and cadcam milled zirconia abutments over titanium implants

Praveen Sundar,Hariharan Ramakrishnan,Jayakrishnakumar Sampathkumar,Nagarasampatti Sivaprakasam Azhagarasan 대한치과이식임플란트학회 2022 The Korean Academy of Implant Dentistry Vol.41 No.2

Purpose: To compare the machining tolerance and vertical microgap at two different implant-abutment interfaces. Materials and Methods: Twenty-four titanium implants (Bioline, Israel) with an internal hex were divided into two groups, A (Bio-HPP PEEK abutment, Norris, Israel) and B (CADCAM milled zirconia abutments, Dentgallop, USA), and embedded in clear auto polymerizing resin and tightened to a torque of 35Ncm. The machining tolerance was then evaluated using a coordinate measuring machine (GMT Grano7-10-6, India) and vertical microgap at the implant abutment interface using a scanning electron microscope (JEOL 6000 PLUS, Japan) at six regions (front right, front centre, front back, back right, back centre, and back left). Data obtained were tabulated and statistically analyzed using an independent t-test. Results: Mean machining tolerances at the implant-abutment interface of the group A and B samples were 126.75 μm and 536.33 μm, respectively, on the x-axis. An independent t-test showed a significant difference in the machining tolerance and vertical microgaps between the two groups in four regions. The microgaps values of four zones of the Group A samples were significantly less than the Group B samples. The front centre zones of the Group A samples had the least vertical microgap compared to the six zones of the Group B samples. The front right zones of the Group A samples had the highest vertical microgaps that were still less than the vertical microgaps of the Group A samples in all six zones (P<0.05). Conclusions: Bio-HPP PEEK abutment-titanium implant interfaces showed a significantly lower machining tolerance and vertical microgaps than the titanium implant-CADCAM Milled zirconia abutment interfaces.

Evaluation of accuracy of different elastomeric materials in open tray implant level technique for single tooth impressions

Sekar Abinaya,Mariappan Saravanakumar,Krishnan Chitra Shankar,Sampathkumar Jayakrishnakumar,Ramakrishnan Hariharan,Mahadevan Vallabh,Sivaprakasam Azhagarasan Nagarasampatti 대한치과이식(임프란트)학회 2022 The Korean Academy of Implant Dentistry Vol.41 No.4

Purpose: This study compared the accuracy of different elastomeric impression materials with open tray implant level impression technique in a single-tooth replacement. Materials and Methods: A reference model representing a single implant with an adjacent simulated natural tooth was fabricated. Open tray implant level impressions were made with vinylpolysiloxane (light body ExpressXT, PentaputtyPentamix2, 3MESPE, Seinfield, Germany) (Group I, n=10) and polyether (medium body Impregnum Penta, Pentamix 2, 3MESPE, Seinfield, Germany), (Group II, n=10) and implant crowns were fabricated on each master cast from their respective impressions by CNC milling and connected to the reference model with 35 Ncm torque. The accuracy of the fit was evaluated by measuring the interface gap between the implant crown and the implant replica at the mesial and distal points and by measuring the proximal gap between the implant crown and the simulated natural tooth at the buccal and the palatal points by scanning electron microscopy for each test sample. The mean values were obtained and statistically analyzed using a Mann-Whitney test. Results: The interface gap observed at the mesial point was significantly higher than the distal point. The proximal gap observed at the palatal point was significantly higher than the buccal point for both Group I and Group II. A comparison of the groups showed that the interface gap at the mesial point and the proximal gap at the buccal and palatal points obtained from polyether impression material were lower than those observed with vinylpolysiloxane group, but the difference was not significant. However, the interface gap observed at the distal point was higher with the polyether group than with the vinylpolysiloxane group, but the difference was not significant. Conclusions: Polyether and vinylpolysiloxane can be used to produce open tray implant impressions for a single missing tooth.

Retention force dynamics of two different soft liners over ball abutments for mandibular implant overdentures

Halder Surabhi,Ramakrishnan Hariharan,Sivaprakasam Azhagarasan Nagarasampatti,Sampathkumar Jayakrishnakumar 대한치과이식(임프란트)학회 2021 The Korean Academy of Implant Dentistry Vol.40 No.1

Purpose: This study was conducted to comparatively evaluate the initial and reduced retention force of two different soft liners over ball abutments for mandibular implant overdentures. Materials and Methods: Two implants corresponding to 33 and 43 (mandibular left and right canine, FDI notation) were placed in a mandibular edentulous heat cure master model with ball abutments of 3 mm diameter and 0.5 mm collar height. Overdentures were processed in heat-activated denture base resin and divided into three groups, group A (n=15), group B (n=15), and group C (n=15). Group A was lined with Ufi-gel P, group B with Molloplast B, and group C was polymerized with plastic caps. Each of the 45 denture bases was subjected to an initial retention force and reduced retention force testing after 3,348 cycles using a servohydraulic testing machine. The dual recess areas and the soft liner bonded to the denture base were observed with a stereomicroscope both before and after the 3,348 cycles. Statistical analysis was performed using the ANOVA Kruskal Wallis test and Wilcoxon signed-rank test. Results: There were insignificant differences (P>0.05) in the mean rank values of all the three groups for reduced retention force after 3,348 cycles and percentage reduction in force. There were significant differences in all the three groups between initial retention force and reduced retention force after 3,348 cycles (P<0.05). Conclusions: Both the liners could be used as attachments for mandibular implant overdentures over the three-year simulation period.

Evaluation of rotational resistance, rotational and vertical discrepancy of three different elastomeric impression materials with open tray implant level impression on a special model

Ambedkar Elumalai,Saravanakumar Mariappan,ChitraShankar Krishnan,Hariharan Ramasubramanian,Jayakrishnakumar Sampathkumar,Hariharan Ramakrishnan,Azhagarasan Nagarasampatti Sivaprakasam,Vallabh Mahadeva 대한치과이식임플란트학회 2021 The Korean Academy of Implant Dentistry Vol.40 No.3

The purpose of this study was to comparatively evaluate the rigidity and accuracy of three different elastomeric impression materials with an open tray implant level impression technique. In Part, I of the study a total of thirty open tray implant level impressions were made with vinylpolysiloxane (n=10), polyether (n=10), and vinylsiloxanether (n=10) impression materials. Implant replicas were connected to the impression coping using a digital screw torque checker. The peak torque values were recorded indicating the maximum rigidity of each group. The mean values were obtained and statistically analyzed using one-way ANOVA and Post-hoc HSD test. In Part II of the study, a total of thirty impressions were made with vinylpolysiloxane (n=10), polyether (n=10), and vinylsiloxanether (n=10) impression materials similarly. Implant replicas were connected to the impression coping with 5 Nㆍcm torque for vinylpolysiloxane and polyether groups. A gentle hand tightening was given to the vinylsiloxanether group. The master casts were poured. Subsequently, linear angle and vertical distance were measured using a coordinate measuring machine. The mean values were obtained and statistically analyzed using one-way ANOVA, posthoc Tukey HSD, and independent t test. Vinylpolysiloxane showed the maximum rotational resistance followed by polyether and the least by vinylsiloxanether and were statistically significant (P<0.05). Polyether showed the least rotational discrepancy than the vinyl polysiloxane and vinylsiloxanether and was statistically significant (P<0.05). Vinylpolysiloxane showed the least vertical discrepancy than the vinylsiloxanether and polyether without any statistical significance (P>0.05). Among the elastomeric impression materials used in this study, vinylpolysiloxane showed the maximum rotational resistance, polyether showed the least rotational discrepancy and the vertical discrepancy of these three materials was not significant.