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Objective: The aim of the present in vitro study was to evaluate the resistance on quasi-static forces and in the fatigue mechanical cycling of a new implant design compared to two other conventional implant designs., Materials and Methods: Eighty-eight implants with their respective abutments were tested and distributed into four groups (n = 22 per group): Morse taper connection implant (MT group), conventional external hexagon implant (EH con group), new Collo implant of external hexagon with the smooth portion out of the bone insertion (EH out group), and new Collo implant of external hexagon with the implant platform inserted to the bone level (EH bl group). All the sets were subjected to quasi-static loading in a universal testing machine, and we measured the maximum resistance force supported by each sample. Another 12 samples from each group were submitted to the cyclic fatigue test at 4 intensities of forces (n = 3 per force): 80%, 60%, 40%, and 20%. The number of cycles supported by each sample at each force intensity was evaluated., Results: The three groups of implants with external hexagon connection had similar maximum strength values of the sets (p > 0.05). Meanwhile, samples from the MT group showed the highest resistance values in comparison to the other three groups (p < 0.05). In the fatigue test, the Collo out group supported a smaller number of cycles that led to the fracture than the other 3 groups proposed at loads of 80%, 60%, and 40%, and only at the load value of 20% all groups had the same performance., Conclusions: Within the limitations of the present in vitro study, the results showed that the new Collo implant performs better when installed at bone level., Competing Interests: The author NBJr is a Director at Implacil De Bortoli Co., but in thepresent study he acted as an advisor (Professor) and provided the materials for this study. The other authors have declared that no competing interests exist. This does not alter ouradherence to PLOS ONE policies on sharing data and materials., (Copyright: © 2023 Bianchini et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Statement of Problem: The use of reduced platform sets (implants and abutments) can help to control crestal bone loss around implants, which is essential for optimizing esthetics and biomechanical behavior. However, the information available on the fracture resistance of implants with a reduced platform is sparse., Purpose: The purpose of this in vitro study was to analyze the maximum fracture strength value of implants with different platform designs during quasistatic fatigue, followed by a simulation of different bone levels of cervical insertion., Material and Methods: One hundred and twenty sets of dental implants and abutments with different diameters and platform designs were tested. All implants had an internal hexagon connection and conical macrogeometry. Four groups (n=30) were studied: Ø4.0-mm implants with a regular matched platform (rMatch group), Ø4.0-mm implants with a regular switched platform (PSwitch group), Ø5.0-mm implants with a wide matched platform (wMatch group), and Ø5.0-mm implants with a wide switched platform (wSwitch group). Three conditions simulating different levels of bone position around the cervical portion of the implants were proposed: insertion at the implant shoulder level=0 mm (L0), level=3 mm of insertion loss (L3), and level=5 mm of insertion loss (L5). All sets of all groups and proposed insertion level were subjected to a fracture strength test at 30 degrees in relation to the axis of the sets in a universal testing machine., Results: Regardless of the insertion levels tested, the switched platform implants (rSwitch and wSwitch groups) showed similar mean fracture strength values (P>.05), while the implants of matched platforms (rMatch and wMatch groups) showed different fracture strength values for all insertion levels tested (P<.001)., Conclusions: The fracture strength values of the switched platform implants were lower at all insertion levels tested. However, for all insertion levels tested, the implants with a switched platform presented less deformation, whereas, in the matched platform implants, there was significant deformation of the implant structure., (Copyright © 2020 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

The aim of the present in vivo study was to analyze and compare the effects on the crestal bone healing of two different implant macrogeometries installed in fresh socket areas and in normal bone areas with different insertion torque values. Two implant macrogeometries were used in the present study, DuoCone implant (DC) and Maestro implant (MAE), forming four groups: group DCws, in which the implants were installed in healing bone (without a socket); group DCfs, in which the implants were installed in post-extraction areas (fresh sockets); group MAEws, in which the implants were installed in healing bone (without a socket); group MAEfs, in which the implants were installed in post-extraction areas (fresh sockets). After 30 and 90 days of implantations in the bilateral mandibles of 10 sheep, eighty implants were evaluated through digital X-ray images and histologic slices. The crestal bone position in relation to the implant platform shoulder was measured and compared. The measured insertion torque was 47.2 ± 4.69 Ncm for the DCws group, 43.4 ± 4.87 Ncm for the DCfs group, 29.3 ± 3.16 Ncm for the MAEws group, and 27.7 ± 4.41 Ncm for the MAEfs group. The radiographic mesio-distal and histological bucco-lingual analyses showed significantly greater vertical bone loss in the implants installed with high torque (DC groups) in comparison to the implants installed with a low torque (MAE groups) (p < 0.05), at both evaluation times. In general, low insertion torque values (Maestro implants) showed better results of MBL when compared to implants installed with higher torque values (Duo Cone implants). Moreover, our results showed that the implants installed in the sites without sockets showed a less MBL in comparison with the implants installed in sites of fresh sockets., (© 2022. The Author(s).)

Background: During the masticatory cycle, loads of different intensities and directions are received by the dental structures and/or implants, which can cause micromovements at the junction between the abutment and implant., Objective: The objective of this in vitro study was to evaluate the behavior of three different implant connections subjected to different load values using a digital radiography system. Additionally, the torque values for removing the abutment screws were also measured and compared., Methods: Ninety sets of implant and abutment (IA) were used, divided into three groups according to the type of connection (n = 30 per group): EH group, external hexagon type connection; IH group, internal hexagon connection; and, MT group, Morse taper connection., Results: MT group showed the better vertical misfit behavior at the three intensity of load applied, in comparison with EH and IH groups. In the analysis of torque maintenance (detorque test), MT group showed higher values of detorque when compared with the measured values of EH and IH groups (p < 0.001)., Conclusions: The IA sets of EH and IH groups showed a microgap in all levels of applied loads, unlike the MT group this event was not observed. In the detorque test, MT group increase in the torque values when compared to the initial torque applied, unlike EH and IH groups showed a decrease in the initially torque applied in all conditions tested. A positive correlation was detected between the misfit and detorque values.

A large number of materials with different compositions and shapes have been proposed and studied for the purpose of bone tissue regeneration. Collagen-based materials have shown promising results for this application, with improved physicochemical properties. The aim of the present in vivo animal study was to evaluate and compare two commercially available collagen-based biomaterials for bone regeneration, with these being implanted in circumferential bone defects created in the calvarium of rabbits. Twenty rabbits received bilateral parietal osteotomies, performed with the aid of a 6.5 mm diameter trephine. Two groups were created: the BC group, where the defect was filled with a scaffold composed of 90% bovine bone particles and 10% porcine collagen, and the EG group, where the defect was filled with a scaffold composed of 75% hydroxyapatite particles of bovine origin and 25% bovine collagen. Ten animals were sacrificed at 30 days and another 10 at 45 days after implantation, and the samples were processed and histologically analyzed. In the evaluations of the samples at 30 days, no important differences were found in the results. However, in the samples at 45 days after surgery, the EG group showed better results than the BC group samples, mainly in terms of the amount of bone matrix formation ( P < 0.0001) and the volume in area measured in each sample, where the EG group had a value 65% higher than that in the BC group samples. Based on the results obtained, we conclude that the amount of collagen and the particle characteristics present in the composition of the scaffolds can directly influence the amount of neoformation and/or bone regeneration.

This study aims to evaluate the effects of implant macrogeometry on the early period of the osseointegration process, comparing four different implant models through biomechanical and histological analysis after implantation in rabbit tibiae. Twenty New Zealand rabbits were used, evaluated at two different times (21 and 28 days) after installation of the implant. Eighty implants with different macrogeometries were used, forming four groups (n = 20 per group): cylindrical implants Ø4.1 mm and 8 mm in length (STRc group); cylindrical-conical implants Ø4.1 mm and 8 mm in length (STRt group); tapered implants Ø4.3 mm and 8 mm in length (NOBt group); and tapered implants with healing chambers Ø4.0 mm and 8 mm in length (MAEt group). Ten samples from each group were analyzed at each proposed time. The initial implant stability quotient (ISQ) was measured by resonance frequency analysis, both at the time of installation and at the time of sacrifice. In the histological sections, the percentage of bone-implant contact (BIC%), newly formed bone, osteoid matrix, and medullary spaces were measured in the pre-determined cortical and medullary bone portion for each sample. The three tapered implant groups (STRt, NOBt, and MAEt) showed higher values for the analyzed parameters in the early osseointegration period, in comparison with the cylindrical implant group (STRc). In all parameters, the three tapered groups showed no difference (p > 0.05); however, all three tapered groups presented significant differences, when compared to the cylindrical group (p < 0.05). No correlation was detected between the parameters analyzed. Within the limitations of the present study, in all parameters analyzed, the tapered implants demonstrated greater results when compared to the cylindrical implants., (Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Various ceramic materials have been used for esthetic rehabilitation with implants, but the issues regarding the dissipation of masticatory loads are not well understood., Objectives: This in vitro quasi-static study aimed to evaluate with the photoelasticity test the dissipation of stress around dental implants with regard to different rehabilitation materials., Material and Methods: A photoelastic model was elaborated in resin, where a conical Morse-tapered implant was inserted. On the abutments (1 per crown), 6 single crowns were prepared using different materials to form 6 groups: feldspathic ceramic (G1); chrome-cobalt alloy covered with ceramic (G2); hybrid ceramic (G3); zirconia covered with ceramic (G4); zirconia (G5); and lithium disilicate (G6). Axial loads of 100 N (load 1) and 300 N (load 2) were applied in the center of the crowns, and photoelastic images were captured and analyzed. The total area of stress dissipation was measured for each group. Then, a computational program was developed to measure the number of pixels of the colors generated in each group. Two image sizes were analyzed - total image and crestal image., Results: Counting the numbers of pixels of the colors in the total images showed that G6 > G4 > G5 > G1 > G2 > G3 when load 1 was applied. When load 2 was applied, the sequence was G6 > G4 > G1 > G3 > G2 > G5. In the evaluation of the crestal area, the obtained results were G4 > G5 > G1 > G3 > G2 > G6 with load 1 and G5 > G1 > G2 > G6 > G4 > G3 with load 2., Conclusions: Within the limitations of this in vitro quasi-static study, the findings indicate that the zirconia crown (G5) presented higher stress in the crestal images, while the lithium disilicate crown (G6) presented higher stress in the total images.

Background: The ideal installation technique or implant macrogeometry for obtaining an adequate osseointegration in low-density bone tissue follows a challenge in the implantology., Aims and Objective: The aim of the present study was to evaluate the behavior of three osteotomy techniques and two implant macrogeometries in two low-density polyurethane blocks. The insertion torque (IT), initial stability, pullout resistance, and weight of the residual bone material deposited on the implants were assessed., Materials and Methods: A total of 120 implants with two different macrogeometries were used. They were divided into six groups according to the implant macrogeometry and the drilling technique performed ( n = 20 implants per group). The implants were installed in polyurethane blocks with pounds per cubic foot (PCF) 10 and PCF 20 densities. The IT, initial stability, pullout resistance, and weight residual bone were measured., Results: Differences were found in the values referring to the macrogeometry of the implants and the type of osteotomy performed. In all groups, the initial stability of the PCF 10 blocks was quite low. The undersized osteotomies significantly increased the values measured in all tests in the PCF 20 density blocks., Conclusions: In conclusion, even when a modified (undersized) osteotomy technique is used, implants inserted in low-quality bone (type IV) can present problems for osseointegration due their low initial stability and bone resistance. However, the modification in the implant macrogeometry (with healing chambers) presented more quantity of bone on the surface after the pullout test., Competing Interests: There are no conflicts of interest., (Copyright: © 2021 Journal of International Society of Preventive and Community Dentistry.)

Objective: To compare the mechanical strength of joints made by conventional soldering with those made by alternative, more biocompatible, methods (spot, tungsten inert gas [TIG] and laser welding), and to compare the microstructural morphology of wires welded with these techniques., Design: In vitro, laboratory study., Methods: Forty stainless-steel wire segments with 0.8-mm diameter were joined by silver soldering, spot, laser and TIG welding. Ten specimens were produced for each one. Tensile strength test was performed 24 h after welding on the Emic DL2000™ universal testing machine, using a load cell of 1000 N with a crosshead speed of 10 mm/min., Results: The highest tensile strength mean values were obtained with silver soldering (532 N), next were laser (420 N), spot (301 N) and TIG (296 N) welding. Statistically significant differences were observed between the groups; the Dunn post-hoc test revealed differences between laser and spot welding ( p =0.046), laser and TIG ( p = 0.016), spot and silver ( p <0.001), and silver and TIG ( p <0.001)., Conclusion: Laser welding strength is high, and comparable to silver welding. Spot and TIG techniques present comparable and significantly lower strengths. The four methods presented resistance values compatible with orthodontic use. The microstructural morphology is different for each technique. The association between the mechanical performance and the microstructure evaluation shows that laser presented the highest quality joint.

Dental implants are not routinely used for rehabilitation in veterinary dentistry. For some veterinarians, further studies are necessary to be considered for clinical use in animals. The objective of the present in vitro study was to evaluate static fatigue of dental implants and to correlate that with the bite strength of dogs described in the literature. Sixty implants and abutments were used with the smallest diameter of each brand of implant utilized in the study. Three groups ( n   =  20) were created on the basis of the implant diameter, all with external hex connector: 3.30 mm (group 1), 4.0 mm (group 2) and 5.0 mm (group 3). All groups were subjected to quasi-static loading at 30° to the implant's long axis in a universal machine (model AME-5 kN). The mean fracture strength for group 1 was 964 ± 187 N, for group 2 was 1618 ± 149 N and for group 3 was 2595 ± 161 N. Significant differences between the groups with respect to resistance after the load applications were observed ( P  < .05). The diameter of implants affects the resistance to external forces during the application of non-axial strength (off-axis loading) and must be considered during the planning of rehabilitation to avoid problems.

Objective: During the insertion of dental implants in the bone tissue, different torque values can be applied. However, the high applied torque can cause damage to the implant connection. Our study sought to evaluate, by measuring the angle of rotation of the insertion drive and, later microscopic observation, possible changes in the structure of implants of different diameters with 3 different types of connections after the application of 4 different torque intensities., Materials and Methods: Three hundred tapered dental implants and three hundred insertion drivers were used in the present study. Implants of 3.5 and 4 mm in diameter with 3 connection models were tested: external hexagon (EH), internal hexagon (IH) and Morse taper (MT). Then, sis groups were performed: EH3 group, EH4 group, IH3 group, IH4 group, MT3 group and MT4 group. The samples were submitted to the torque/torsion force at 4 intensities (n = 10 samples per group and intensity): 60, 80, 100 and 120 Ncm. The turning angle of the insertion driver was measured in each test. In addition, in 10 samples from each group, the maximum torque value supported by each implant model was measured. After the tests, all samples were inspected microscopically to describe the observed changes., Results: The maximum torque supported by the different implant models showed statistically significant difference (p < 0.0001). The values of the measured angles showed statistically significant differences between the torque values applied within each group (p < 0.001) and between groups with the same torque value (p < 0.001)., Conclusions: Within the limitations of the present study in vitro, the results showed that high torque values cause mechanical damage to the implants., Competing Interests: The authors have read the journal’s policy and have the following potential competing interests: SAG is a paid employee of Biotecnos and NBJr is a Director of Implacil De Bortoli. This does not alter our adherence to PLOS ONE policies on sharing data and materials. There are no patents, products in development or marketed products associated with this research to declare.

The objective of this study was to evaluate a new design of multifunctional abutment for Morse taper implant connections, relative to the retentive stability after the application of cyclic loads in cemented and screwed crowns. Multifunctional abutments with two different angulations in the seating portion of the crown were tested, forming 2 groups (n = 30 samples per group): Group Abut11, where Smart abutments with an angle of 11.42° were used; Group Abut5, where Ideale abutments with an angle of 5° were used. Fifteen samples from each group received cemented crowns (CC) and another fifteen screwed crowns (SC). All crown samples were subjected to the mechanical cycling test at 360,000 cycles at a frequency of 4 Hz and 150 N of the load. The samples with CC were subjected to the tensile test to remove the crowns, while in the samples with SC, the detorque value of the fastening crown screws was measured. The mean tensile strength value of CC in the Abut11 group was 131.9 ± 13.5 N and, in the Abut5 group was 230.9 ± 11.3 N; while the detorque mean value in samples with SC 5.8 ± 1.8 N for the Abut11 group and, 7.6 ± 1.1 N for Abut5 group. Significant statistical differences were found between the two groups in both situations tested (p < 0.05). The multifunctional abutments, presenting a lesser angulation of the crown-seating portion, showed higher values of retention of the CC and a lesser screw loosening of torque of the fixing screws in the SC after the application of cyclic loads when compared to the abutments with more angulation in the crown-seating portion., (Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The present in vitro study evaluated a new drill design to improve the temperature control during the osteotomies for dental implant installation, comparing with two drill designs that use conventional external irrigation. Three blocks of synthetic cortical bone were used for osteotomy procedures. Three groups were created: control group 1 (Con1), where a conical multiple drill system with a conventional external irrigation system was used; control group 2 (Con2), where a single bur with a conventional external irrigation system was used; and, test group (Test), where the new single bur (turbo drill) with a new irrigation system was used. Twenty osteotomies were made without irrigation and with intense irrigation, for each group. A thermocouple was used to measure the temperature produced during the osteotomies. The measured temperature were: 28.9 ± 1.68 °C for group Con1; 27.5 ± 1.32 °C for group Con2; 26.3 ± 1.28 °C for group Test. Whereas, the measured temperatures with irrigation were: 23.1 ± 1.27 °C for group Con1; 21.7 ± 1.36 °C for group Con2; 19.4 ± 1.29 °C for group Test. The single drill with a new design for improving the irrigation and temperature control, in comparison with the drill designs with conventional external irrigation.

Objectives: The propose was to compare this new implant macrogeometry with a control implant with a conventional macrogeometry., Materials and Methods: Eighty-six conical implants were divided in two groups (n = 43 per group): group control (group CON) that were used conical implants with a conventional macrogeometry and, group test (group TEST) that were used implants with the new macrogeometry. The new implant macrogeometry show several circular healing cambers between the threads, distributed in the implant body. Three implants of each group were used to scanning electronic microscopy (SEM) analysis and, other eighty samples (n = 40 per group) were inserted the tibia of ten rabbit (n = 2 per tibia), determined by randomization. The animals were sacrificed (n = 5 per time) at 3-weeks (Time 1) and at 4-weeks after the implantations (Time 2). The biomechanical evaluation proposed was the measurement of the implant stability quotient (ISQ) and the removal torque values (RTv). The microscopical analysis was a histomorphometric measurement of the bone to implant contact (%BIC) and the SEM evaluation of the bone adhered on the removed implants., Results: The results showed that the implants of the group TEST produced a significant enhancement in the osseointegration in comparison with the group CON. The ISQ and RTv tests showed superior values for the group TEST in the both measured times (3- and 4-weeks), with significant differences (p < 0.05). More residual bone in quantity and quality was observed in the samples of the group TEST on the surface of the removed implants. Moreover, the %BIC demonstrated an important increasing for the group TEST in both times, with statistical differences (in Time 1 p = 0.0103 and in Time 2 p < 0.0003)., Conclusions: Then, we can conclude that the alterations in the implant macrogeometry promote several benefits on the osseointegration process., Competing Interests: The authors have read the journal’s policy and have the following potential competing interests: SAG is a paid employee of Biotecnos. This does not alter our adherence to PLOS ONE policies on sharing data and materials. There are no patents, products in development or marketed products associated with this research to declare.

Purpose: This study investigated the effect of fracture strength and fracture mode characteristics related to reduced interocclusal space on computer-aided design/computer-aided manufacturing (CAD/CAM). ZrO 2 fixed partial denture (FPD) frameworks subjected to quasi-static loads., Materials and Methods: First, two dental implants (4 × 10 mm) were positioned simulating a three-unit FPD (second premolar and second molar abutments). The implants were distributed into two groups: control group (n = 10), positioned at the same level; and the test group (n = 10), where the interocclusal space corresponding to the second molar was reduced by 3 mm in relation to the second premolar to simulate a clinical situation. After FPD wax-up (25-mm long; connector height = 5 mm; connector width = 3 mm, proximal and lingual collar reinforcement), casting was made in a Co-Cr alloy to serve as a prototype. Upon scanning, screw-retained CAD/CAM ZrO 2 FPDs were fabricated for each group. Then, FPDs were subjected to quasi-static axial loading until fracture in the mid-occlusal pontic area using a universal testing machine at the crosshead speed of 0.5 mm/min. Next, the samples were analyzed by scanning electronic microscopy (SEM) to describe the fracture characteristics., Results: The mean fracture strength values for the control group (1,747.4 ± 122.3 N) and test group (1,817.7 ± 158.9 N) showed no significant difference (Student t test, P < .124). The SEM images of the fracture sites revealed two cleavage areas in the test group, providing representative sites with increased fracture energy storage in this group compared with the control group., Conclusion: Within the limitations of this study, the results showed that reduced interocclusal space and reduced length did not decrease the fracture strength of the ZrO 2 FPD frameworks.

Background: The objective of the present histologic animal study was to analyze whether roughness of the titanium surface can influence and/or stimulate the bone growth in defects filled with the blood using a rabbit tibia model., Materials and Methods: Forty sets (implant and abutment), dental implant (3.5 mm in diameter and 7 mm in length) plus healing abutment (2.5 mm in diameter), were inserted in the tibiae of 10 rabbits. Moreover, twenty titanium discs were prepared. The abutment and discs were treated by 4 different methods and divided into 4 groups: (group A) machined abutments (smooth); (group B) double acid etching treatment; (group C) treatment with blasting with particles of aluminum oxide blasted plus acid conditioning; (group D) treatment with thorough blasting with particles of titanium oxide plus acid conditioning. The discs were used to characterize the surfaces by a profilometer and scanning electronic microscopy., Results: After 8 weeks, the new bone formation around the sets of the samples was analyzed qualitatively and quantitatively in relation to bone height from the base of the implant and presence of osteocytes. Group C (1.50±0.20 mm) and group D (1.62±0.18 mm) showed bone growth on the abutment with higher values compared to group A (0.94±0.30 mm) and group B (1.19±0.23 mm), with significant difference between the groups (P < 0.05). In addition, osteocyte presence was higher in groups with surface treatment related to machined (P < 0.05)., Conclusions: Within the limitations of the present study, it was possible to observe that there is a direct relationship between the roughness present on the titanium surface and the stimulus for bone formation, since the presence of larger amounts of osteocytes on SLA surfaces evidenced this fact. Furthermore, the increased formation of bone tissue in height demonstrates that there is an important difference between the physical and chemical methods used for surface treatment.

Background: New manufacturing methods was developed to improve the tissues integration with the titanium alloy pieces., Objective: The present in vitro study was to assess the resistance and fracture mode after applied a quasi-static compressive force on the two dental implants manufactured by direct metal laser sintering., Materials and Methods: Twenty dental implants manufactured by direct metal laser sintering, using titanium alloy (Ti-6Al-4V) granules in two designs (n = 10 per group): Conventional dental implant (group Imp1) two-piece implant design, where the surgical implant and prosthetic abutment are two separate components and, the one-piece implant (group Imp2), where the surgical implant and prosthetic abutment are one integral piece. All samples were subjected to quasi-static loading at a 30° angle to the implant axis in a universal testing machine., Results: The mean fracture strengths were 1269.2 ± 128.8 N for the group Imp1 and, 1259.5 ± 115.1 N for the group Imp2, without statistical differences (P = .8722). In both groups, the fracture surface does not present crack between the compact core and the superficial (less dense and porous) part of the implants., Conclusions: Based on the measured resistance data for the two implant models manufactured by direct metal laser sintering tested in the present study, we can suggest that they have adequate capacity to withstand the masticatory loads., (© 2018 Wiley Periodicals, Inc.)

Background: The topographical surficial characteristics and properties of materials can induce different cell reactions regarding the viability and adhesion according to the recent patents. The aim of this in vitro experimental study was to evaluate the viability and adhesion of fibroblastic cells seeded on titanium disks with different surface topography. In addition, we revised all patents related to surface treatment of dental implants., Methods: Fibroblast cells were cultured on 6 surface models: mA disks corresponding to titanium surfaces without additional treatment (machined surface) were compared with mB disks, where surfaces were sandblasting etching using aluminum oxide; mC disks where titanium oxide was used for sandblasting etching; mD disks where triple acid conditioning was used; mE disks with laser treated surface; and mF disks which were made of titanium powder by a sintering process. Different surfaces were analyzed using an optical laser profilometer and SEM analysis. To evaluate cell viability on different disc surfaces, a fibroblast cell line derived from monkey kidney (VERO) was in vitro cultured on treated disks surface and cell viability assays were performed to compare growth of fibroblastic cells. Then, the adhesion of the cells was tested by washing procedure., Results: The disks mA, mB, mC and mD less pronounced rugosities were observed and, disc in the mE and mF disks displayed a deeper pronounced surface. The cell viability and adhesion analysis showed significant higher levels on titanium disks surface obtained by the mF method., Conclusion: Our analysis showed that the surface morphology of titanium disc, independent of the roughness parameters, affects cell viability and adhesion differentially, since a higher percentage of viable and attached cells were observed on the mF disks in comparison with the other evaluated surfaces., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.)

Purpose: This study aimed to evaluate the misfit of three different implant-abutment connections before and after cycling load., Materials and Methods: One hundred twenty dental implants and correspondent prefabricated titanium abutments were used. Three different implant-abutment connections were evaluated: Morse taper (MT group), external hexagon (EH group), and internal hexagon (IH group). Forty implants and 40 abutments were used per group. The parameters for the mechanical evaluation were set as: 360,000 cycles, load of 150 N, and frequency of 4 Hz. Samples were sectioned in their longitudinal and transversal axes, and the misfit of the implant-abutment connection was evaluated by scanning electron microscopy analysis. One-way analyses of variance, Tukey post hoc analyses (α = .05), and t test (P < .05) were used to determine differences between groups., Results: At the longitudinal direction, all the groups showed the presence of microgaps before cycling load; after cycling load, microgaps were reduced in all groups (P > .05). Transversally, only the MT group showed full fitting after cycling load compared with the other groups (EH and IH) (P < .0001)., Conclusion: The application of cycling load produces an accommodation of the implant-abutment connection in internal, external, and Morse taper connections. In the longitudinal direction, the accommodation decreases and/or eliminates the gap observed initially (before load). In the horizontal direction, Morse cone implant-abutment connections experience a complete accommodation with the elimination of the gap.

Statement of Problem: Esthetic factors influence the decision to use titanium or zirconia abutments in anterior regions. Clinicians may have concerns about the durability and behavior of these zirconia abutments., Purpose: The purpose of this in vitro study was to evaluate the longitudinal and transverse long axes of the implant-abutment interface before and after the cyclic loading of titanium and zirconia abutments with an external hexagon., Material and Methods: Forty dental implants with an external hexagon and 40 corresponding abutments made of titanium (Ti) and zirconia (Zr) were subjected to cyclic load (c1) versus no load (c2). The longitudinal and transverse axes of 4 experimental groups (Tic1, Tic2, Zrc1, and Zrc2) were analyzed (vertical/horizontal adjustment) using a scanning electron microscope at ×1000 magnification. The differences among the groups were determined by 1-way analysis of variance (ANOVA) and post hoc Tukey tests (α=.05). T tests were used to identify the statistically significant differences between each group and each condition (α=.05)., Results: Significant differences were found among the groups with respect to the misfits analyzed in the 2 sections (longitudinal and transverse) before and after load application (P<.05). The behaviors of the groups differed particularly with regard to the accommodation of sets (abutment/implant) after the application of cyclic loads (P<.05)., Conclusion: The use of zirconia abutments in titanium implants can cause changes to and/or permanent deformation of the implant hexagon., (Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Purpose: The aim of this in vitro study was to assess the resistance to static fatigue of implants with different connections before and after implantoplasty., Materials and Methods: Sixty conical implants and 60 abutments were used; 4-mm-diameter versions were available for each model. Three groups (n = 20) were established based on the following implant connections: external hexagon (group 1), internal hexagon (group 2), and Morse taper (group 3). The implants of each group were submitted to a compressive load before (n = 10) and after the implantoplasty (n = 10). The wear was performed in a mechanical lathe machine using a carbide bur, and the final dimensions of each sample were measured. All groups were subjected to quasi-static loading at a 30-degree angle to the implant axis in a universal testing machine and 5 mm out of the implant support., Results: After the implantoplasty, the mean final diameter was 3.13 ± 0.033 mm for group 1, 3.23 ± 0.023 mm for group 2, and 3.25 ± 0.03 mm for group 3. The mean fracture strengths for the groups before and after the implantoplasty were, respectively, 773.1 ± 13.16 N and 487.1 ± 93.72 N in group 1; 829.4 ± 14.12 N and 495.7 ± 85.24 N in group 2; and 898.1 ± 19.25 N and 717.6 ± 77.25 N in group 3., Conclusion: Resistance to loading decreased significantly after implantoplasty, and varied among the three implant connection designs.

The fit of the implant-abutment interface was assessed by the metallographic technique and by scanning electron microscopy (SEM), using solid abutment types at different torque levels. Forty Morse taper connections and forty solid abutments were used at different torque levels (repeated after 10 minutes) in the following groups (n = 10): 25 Ncm (group g1), 30 Ncm (group g2), 35 Ncm (group g3), and 40 Ncm (group g4). The samples were embedded in a metallographic resin, sectioned lengthwise, and polished. SEM images were used to measure the linear contacts and the fits between abutments and the internal walls of the implant. The overall mean gap and standard deviation were as follows: 9.0 ± 1.36 µm for group g1, 7.9 ± 2.81 µm for group g2, 2.0 ± 0.76 µm for group g3, and 0.3 ± 0.40 µm for group g4. A significant difference was observed in the average fit values between the groups (p < 0.05). The linear area of contact between the abutment and the implant increased as torque augmented. This study demonstrated that higher insertion torque values in a conical internal connection increase the fit (contact) of the implant-abutment interface.

Objective: The aim of the present in vitro study was to assess resistance to static fatigue of implants with different connections at various insertion levels., Materials and Methods: Sixty implants and abutments were used with the smallest diameter of each model. Four groups (n = 15) were created on the basis of the implant design and connection: cylindrical external hexagon Ø3.30 mm (group 1), cylindrical internal hexagon Ø3.30 mm (group 2), conical internal hexagon Ø3.50 mm (group 3), and conical Morse taper Ø3.50 mm (group 4). Three insertion levels in resin were tested, 0 mm at the platform level (l1), 3 mm (l2), and 5 mm (l3) above the platform of the resin. All groups were subjected to quasi-static loading at 30° to the implant axis in a universal machine., Results: The mean fracture strengths for group 1 were 1,991 N (l1), 1,020 N (l2), and 767 N (l3); for group 2: 2,119 N (l1), 1,034 N (l2), and 903 N (l3); for group 3: 2,373 N (l1), 1,407 N (l2), and 929 N (l3); and for group 4: 1,710 N (l1), 1,680 N (l2), and 1,182 N (l3)., Conclusions: Resistance to loading decreases significantly with the loss of insertion, and the connection design between the implants and abutments can change the performance and resistance of the system., Clinical Relevance: When implants are used in areas where there is a possibility of bone loss, the selection of a connection type is an important consideration for the longevity of the system.

Aim: Periradicular surgery is a procedure that includes surgical exposure of the diseased apex, root-end cavity preparation, and retrofilling of the root canal. The aim of this study was to compare the outcomes of periradicular surgery in vitro using different dental materials and storage methods for human teeth specimens., Methods: The sample comprised 60 human single-rooted teeth, divided into two groups according to mode of storage (hydrated or non-hydrated); each group was then subdivided by retrofilling material (mineral trioxide aggregate or resin-modified glass ionomer cement). Each specimen was analyzed by digital radiography and scanning electron microscopy (SEM). Quantitative assessment of the gap between the retrofilling material and dentin surface was conducted by observation of apical views (2000x magnification) of four areas of each specimen., Results: The gap between retrofilling material and the internal dentin surface of the root was found to be significantly wider in hydrated teeth (P=0.002). Comparison of the two retrofilling materials showed that, regardless of tooth storage method, use of glass ionomer cement was associated with significantly wider gaps between the filling material and dentin surface (P=0.001). Comparisons of tooth storage mode versus retrofilling material showed a statistical interaction (P=0.009) between these factors., Conclusion: Mineral trioxide aggregate (MTA®) provided the best apical sealing, regardless of storage medium. Resin-modified glass ionomer cement (Vitremer®) was associated with substantially larger mean gap values when used in hydrated teeth.