Comparison of the Effect of Four Different Abutment Screw Torques on Screw Loosening in Single Implant-Supported Prosthesis after the Application of Mechanical Loading

Background. The complications of implant-supported prostheses can be classified into mechanical and biological ones, one part of which is associated with screw loosening. This study was aimed to compare the effect of four different abutment screw torque techniques on screw loosening in single implant-supported prostheses following the application of mechanical loading. Materials and Methods. In this experimental study, a total of 40 implants in acrylic blocks (6 × 10 × 20 mm) were mounted perpendicular to the surface. They were then randomly divided into four groups: (1) torquing once with 30 Ncm, (2) torquing three times with 30 Ncm and 5-minute intervals, (3) torquing once with 30 Ncm, opening the screw, and retorquing with 30 Ncm, and (4) torquing once with 35 Ncm. The torque values were confirmed by using a digital torque meter. Then, the samples underwent a force (2 cps, 0.453–11.793 kg) for three hours before the measurement of detorque values. The screw loosening force (torque) was then measured and recorded. The obtained data were analyzed by SPSS (version 22) software using one-way ANOVA and Tukey post hoc test at a 5% error level. Results. The maximum mean detorque values of the abutment screws in single implant-supported prostheses were reported for groups 4 (27.8 ± 1.3), 1 (26.8 ± 1.3), and 3 (25.1 ± 1.3), and the minimum mean detorque value was found in group 2 (24.9 ± 1.2). Moreover, no significant difference was observed between groups 2 and 3 ( p > 0.05 ), but a significant difference was found between groups 1 and 3 and other groups ( p < 0.05 ). Conclusion. The increase in the torque value increased the torque loss. However, the detorque value in group 4 showed the least difference with the value recommended by the manufacturer (30 Ncm).

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Comparing Torque Loss in Standard Implants and Short Implants with Increased Vertical Cantilever Abutments: an In Vitro Study

Brazilian Dental Science ◽

10.14295/bds.2021.v24i1.1985 ◽

2020 ◽

Vol 24 (1) ◽

Author(s):

Ezzatollah Jalalian ◽

Zahra Yousofi

Keyword(s):

In Vitro Study ◽

Longitudinal Axis ◽

Screw Loosening ◽

Reverse Torque ◽

Short Implants ◽

Significant Difference ◽

Torque Loss ◽

Student’S T ◽

Abutment Screw

Objectives: With regard to the prevalence of abutment screw loosening (SL) and bone height reduction, particularly in the posterior regions of the jaws, as well as the contradictory issue of applying short implants instead of surgeries, along with all preparations associated with longer implants, the present study aimed to compare the amount of torque loss in short implants with increased vertical cantilever abutments and standard ones. Material and Methods: In this experimental study, a total number of 20 implants (MegaGen Implant Co., Ltd, South Korea) with 4.5 mm diameter including 10 short implants (7 mm) and 10 standard ones (10 mm) were utilized. Using a surveyor, fixtures were perpendicularly mounted in 13×34 mm resin for short implants and 19×34 mm resin for standard ones. The abutments of the same height but different cuff heights (2.5 mm for the standard implants and 5.5 mm for the short ones) were then tightened with 30 N.cm, via a digital torque meter. To compensate the settling effect, the abutment screw was re-tightened with 30 N.cm after 10 min. Upon applying 500,000 cycles at 75 N.cm and 1 Hz along the longitudinal axis on each sample, blind reverse torque value (RTV) was measured with a digital torque meter. The data were finally analyzed using Student’s t-test. Results: Both groups experienced torque loss, but there was no statistically significant difference between the case and control groups in terms of abutment SL (p = 0451). Conclusion: Short implants seem to be a good mechanical alternative in emergencies with respect to torque loss and abutment SL. KEYWORDS Reverse torque value; Cyclic loading, Short implant; Screw loosening; Crown-implant ratio; Torque loss.

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Effect of Wet Field on the DE Torque Values of Abutment Screws

International Journal of Research in Pharmaceutical Sciences ◽

10.26452/ijrps.v11ispl3.3034 ◽

2020 ◽

Vol 11 (SPL3) ◽

pp. 843-846

Author(s):

Pravinya Sam ◽

Suresh Venugopalan ◽

Dhanraj Ganapathy

Keyword(s):

Artificial Saliva ◽

Blood Clot ◽

Screw Loosening ◽

Screw Hole ◽

Significant Difference ◽

Implant Abutment ◽

Torque Values ◽

Soft Tissue Inflammation ◽

Plaster Models ◽

Abutment Screw

Screw loosening is amongst the most prevalent mechanical problems in dental implant prosthetics. Clinicians will know if the reverse Detorque values are compromised by contamination of the implant abutment screw hole either by blood , saliva or saline. Research have shown that the drying of the implant cavity may decrease the preload value when the abutment screw is closed and thereafter increase the likelihood of abutment screw loosening. Mobility of the prosthesis, or screw fracture and increase the risk of peri-implant soft-tissue inflammation. This study aims to assess and compare the effect of wet and dry fields while torqueing the abutment screws on the DE torque values. 40 Nobel bio care implant analogues mounted in plaster models were used in this study. The samples were divided into four groups dry abutment screws, artificial saliva, blood and normal saline. All the abutment screws were tightened till 20 Ncm and left aside for 15 minutes. After 15 minutes the abutment screw were DE torqued, and the DE torque values were noted for tall the groups. When analysed using paired sample t-test there was no significant difference with artificial saliva (p=0.269). There was statistical difference with blood (p=0.00) and with saline (p=0.00). Based on this study, the presence of saliva decreases the DE torque values of the abutment screws, whereas Blood and saline increase the DE torque values of the abutment screws. The presence of blood clot might be the reason for the increase in DE torque values which might decrease once the clot disintegrates. Clinicians should prevent contamination of the screw hole by blood and saliva; if contamination arises, sanitation of the infected screw and also the screw hole until final tightening is advised.

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Evaluation of the Sealing Capability of the Internal Conical Connections of Implants with Titanium and Zirconia Abutments

The Journal of Contemporary Dental Practice ◽

10.5005/jp-journals-10024-2149 ◽

2017 ◽

Vol 18 (10) ◽

pp. 915-922 ◽

Cited By ~ 2

Author(s):

Ilser Turkyilmaz ◽

Damian L Black ◽

Chol H Chong

Keyword(s):

P Value ◽

Colony Forming Units ◽

Significant Difference ◽

Implant Abutment ◽

Level Of Significance ◽

Torque Values ◽

Post Hoc ◽

Positive Controls ◽

Abutment Screw

ABSTRACT Aim The purpose of this in vitro investigation was to evaluate the sealing capability of the conical implant–abutment interfaces under different abutment screw torque values using titanium and zirconia abutments with Morse taper designs. Materials and methods A total of 42 dental implants (n = 21 for titanium abutments and n = 21 for zirconia abutments) were inoculated internally with three bacteria. These assemblies were divided into four test groups (n = 10) based on screw fixation torques of 35 or 20 Ncm and placed in sterile broth; the remaining abutments were used as positive controls and torqued to 10 Ncm. Microleakage was quantified by enumerating the bacteria from the colony-forming units. An analysis of variance for the estimates of bacteria enumerated and microgaps was used with a post hoc analysis as indicated. A p-value of 0.05 was used as the level of significance. Results There was no statistically significant difference in microleakage among the four test groups; there were no significant effects of screw torque or abutment type on the bacteria enumerated. There was a significantly smaller mean microgap with the zirconia abutments. Conclusion The results of this study indicated no statistically significant difference in the sealing capabilities between titanium and zirconia abutments, having internal conical connections, after increasing the abutment screw torque. Clinical significance It is important for clinicians to follow the guidelines suggested by the implant companies to avoid biomechanical complications over time. How to cite this article Black DL, Turkyilmaz I, Lien W, Chong CH. Evaluation of the Sealing Capability of the Internal Conical Connections of Implants with Titanium and Zirconia Abutments. J Contemp Dent Pract 2017;18(10):915-922.

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In-vivo evaluation of the effect of cyanoacrylate on prosthetic vascular graft infection – does cyanoacrylate increase the severity of infection?

VASA ◽

10.1024/0301-1526/a000867 ◽

2020 ◽

Vol 49 (4) ◽

pp. 281-284

Author(s):

Atıf Yolgosteren ◽

Gencehan Kumtepe ◽

Melda Payaslioglu ◽

Cuneyt Ozakin

Keyword(s):

Vascular Graft ◽

Graft Infection ◽

Vascular Graft Infection ◽

Group 4 ◽

Significant Difference ◽

Group 3 ◽

Group 2 ◽

Prosthetic Vascular Graft Infection ◽

Group 1

Summary. Background: Prosthetic vascular graft infection (PVGI) is a complication with high mortality. Cyanoacrylate (CA) is an adhesive which has been used in a number of surgical procedures. In this in-vivo study, we aimed to evaluate the relationship between PVGI and CA. Materials and methods: Thirty-two rats were equally divided into four groups. Pouch was formed on back of rats until deep fascia. In group 1, vascular graft with polyethyleneterephthalate (PET) was placed into pouch. In group 2, MRSA strain with a density of 1 ml 0.5 MacFarland was injected into pouch. In group 3, 1 cm 2 vascular graft with PET piece was placed into pouch and MRSA strain with a density of 1 ml 0.5 MacFarland was injected. In group 4, 1 cm 2 vascular graft with PET piece impregnated with N-butyl cyanoacrylate-based adhesive was placed and MRSA strain with a density of 1 ml 0.5 MacFarland was injected. All rats were scarified in 96th hour, culture samples were taken where intervention was performed and were evaluated microbiologically. Bacteria reproducing in each group were numerically evaluated based on colony-forming unit (CFU/ml) and compared by taking their average. Results: MRSA reproduction of 0 CFU/ml in group 1, of 1410 CFU/ml in group 2, of 180 200 CFU/ml in group 3 and of 625 300 CFU/ml in group 4 was present. A statistically significant difference was present between group 1 and group 4 (p < 0.01), between group 2 and group 4 (p < 0.01), between group 3 and group 4 (p < 0.05). In terms of reproduction, no statistically significant difference was found in group 1, group 2, group 3 in themselves. Conclusions: We observed that the rate of infection increased in the cyanoacyrylate group where cyanoacrylate was used. We think that surgeon should be more careful in using CA in vascular surgery.

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Biomechanical properties of the bone during implant placement

BMC Oral Health ◽

10.1186/s12903-021-01442-1 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Ádám László Nagy ◽

Zsolt Tóth ◽

Tamás Tarjányi ◽

Nándor Tamás Práger ◽

Zoltán Lajos Baráth

Keyword(s):

Bone Structure ◽

Biomechanical Properties ◽

Control Group ◽

Dynamic Tests ◽

Bone Model ◽

Implant Placement ◽

Significant Difference ◽

Before And After ◽

Group 2 ◽

Post Hoc

Abstract Background In this research the biomechanical properties of a bone model was examined. Porcine ribs are used as experimental model. The objective of this research was to investigate and compare the biomechanical properties of the bone model before and after implant placement. Methods The bone samples were divided in three groups, Group 1 where ALL-ON-FOUR protocol was used during pre-drilling and placing the implants, Group 2 where ALL-ON-FOUR protocol was used during pre-drilling, and implants were not placed, and Group 3 consisting of intact bones served as a control group. Static and dynamic loading was applied for examining the model samples. Kruskal–Wallis statistical test and as a post-hoc test Mann–Whitney U test was performed to analyze experimental results. Results According to the results of the static loading, there was no significant difference between the implanted and original ribs, however, the toughness values of the bones decreased largely on account of predrilling the bones. The analysis of dynamic fatigue measurements by Kruskal–Wallis test showed significant differences between the intact and predrilled bones. Conclusion The pre-drilled bone was much weaker in both static and dynamic tests than the natural or implanted specimens. According to the results of the dynamic tests and after a certain loading cycle the implanted samples behaved the same way as the control samples, which suggests that implantation have stabilized the skeletal bone structure.

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The Association of Pre-Existing Left Atrial Fibrosis with Clinical Variables in Patients Referred for Catheter Ablation of Atrial Fibrillation

Clinical Medicine Insights Cardiology ◽

10.4137/cmc.s15036 ◽

2014 ◽

Vol 8s1 ◽

pp. CMC.S15036 ◽

Cited By ~ 7

Author(s):

Jane Dewire ◽

Irfan M. Khurram ◽

Farhad Pashakhanloo ◽

David Spragg ◽

Joseph E. Marine ◽

...

Keyword(s):

Atrial Fibrillation ◽

Catheter Ablation ◽

Left Atrial ◽

Af Ablation ◽

Group 4 ◽

Significant Difference ◽

History Of ◽

Group 2 ◽

Magnetic Resonance Imaging Mri ◽

Left Atrial Fibrosis

Introduction Atrial fibrillation (AF) recurrence after ablation is associated with left atrial (LA) fibrosis on late gadolinium enhanced (LGE) magnetic resonance imaging (MRI). We sought to determine pre-ablation, clinical characteristics that associate with the extent of LA fibrosis in patients undergoing catheter ablation for AF. Methods and Results Consecutive patients presenting for catheter ablation of AF were enrolled and underwent LGE-MRI prior to initial AF ablation. The extent of fibrosis as a percentage of total LA myocardium was calculated in all patients prior to ablation. The cohort was divided into quartiles based on the percentage of fibrosis. Of 60 patients enrolled in the cohort, 13 had <5% fibrosis (Group 1), 15 had 5-7% fibrosis (Group 2), 17 had 8-13% fibrosis (Group 3), and 15 had 14-36% fibrosis (Group 4). The extent of LA fibrosis was positively associated with time in continuous AF, and the presence of persistent or longstanding persistent AF. However, no statistically significant difference was observed in the presence of comorbid conditions, age, BMI, LA volume, or family history of AF among the four groups. After adjusting for diabetes and hypertension in a multivariable linear regression model, paroxysmal AF remained independently and negatively associated with the extent of fibrosis (-4.0 ± 1.8, P = 0.034). Conclusion The extent of LA fibrosis in patients undergoing AF ablation is associated with AF type and time in continuous AF. Our results suggest that the presence and duration of AF are primary determinants of increased atrial LGE.

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Microleakage beneath Ceramic and Metal Brackets Bonded with a Conventional and an Antibacterial Adhesive System

The Angle Orthodontist ◽

10.2319/101805-368 ◽

2006 ◽

Vol 76 (6) ◽

pp. 1028-1034 ◽

Cited By ~ 32

Author(s):

Neslihan Arhun ◽

Ayca Arman ◽

Sevi Burçak Çehreli ◽

Serdar Arıkan ◽

Erdem Karabulut ◽

...

Keyword(s):

Adhesive System ◽

White Spot Lesions ◽

Adhesive Interface ◽

Group 4 ◽

Significant Difference ◽

Ceramic Brackets ◽

Group 3 ◽

Group 2 ◽

Ceramic Bracket ◽

Nail Varnish

Abstract Objective: To assess microleakage of a tooth-adhesive-bracket complex when metal or ceramic brackets were bonded with a conventional and an antibacterial self-etching adhesive. Materials and Methods: Forty freshly extracted human premolars were randomly assigned to four equal groups and received the following treatments: group 1 = Transbond XT + metal bracket, group 2 = Transbond XT + ceramic bracket, group 3 = Clearfil Protect Bond + ceramic bracket, and group 4 = Clearfil Protect Bond + metal bracket. After photopolymerization, the teeth were kept in distilled water for 1 month and thereafter subjected to thermal cycling (500 cycles). Specimens were further sealed with nail varnish, stained with 0.5% basic fuchsin for 24 hours, sectioned and examined under a stereomicroscope, and scored for marginal microleakage for the adhesive-tooth and bracket-adhesive interfaces from incisal and gingival margins. Statistical analysis was accomplished by Kruskal-Wallis test and Mann-Whitney U-test with Bonferroni correction. Results: All groups demonstrated microleakage between the adhesive-enamel and bracket-adhesive interfaces. A significant difference was observed among all groups (P < .05) for the microleakage between the bracket-adhesive interface. Metal brackets exhibited significantly more microleakage than did ceramic brackets between the bracket-adhesive interface with either of the adhesives. Clearfil Protect Bond exhibited results similar to Transbond XT. Clearfil Protect Bond may be a choice of adhesive in bracket bonding because of its antibacterial activity and similar microleakage results with the orthodontic adhesive. Conclusions: Metal brackets cause more leakage between an adhesive-bracket interface, which may lead to lower clinical shear bond strength and white-spot lesions.

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Fracture resistance of immature teeth filled with mineral trioxide aggregate, bioaggregate, and biodentine

European Journal of Dentistry ◽

10.4103/1305-7456.178310 ◽

2016 ◽

Vol 10 (02) ◽

pp. 220-224 ◽

Cited By ~ 6

Author(s):

Emre Bayram ◽

Huda Melike Bayram

Keyword(s):

Fracture Resistance ◽

Mineral Trioxide Aggregate ◽

Mean Values ◽

Root Canals ◽

Immature Teeth ◽

Significant Difference ◽

Group 3 ◽

Group 2 ◽

Post Hoc ◽

Group 1

ABSTRACT Objective: The purpose of this study was to evaluate fracture resistance of teeth with immature apices treated with coronal placement of mineral trioxide aggregate (MTA), bioaggregate (BA), and Biodentine. Materials and Methods: Forty-one freshly extracted, single-rooted human premolar teeth were used for the study. At first, the root length was standardized to 9 mm. The crown-down technique was used for the preparation of the root canals using the rotary ProTaper system (Dentsply Maillefer, Ballaigues, Switzerland) of F3 (30). Peeso reamer no. 6 was stepped out from the apex to simulate an incompletely formed root. The prepared roots were randomly assigned to one control (n = 5) and three experimental (n = 12) groups, as described below. Group 1: White MTA (Angelus, Londrina, Brazil) was prepared as per the manufacturer's instructions and compacted into the root canal using MAP system (Dentsply Maillefer, Ballaigues, Switzerland) and condensed by pluggers (Angelus, Londrina, Brazil). Group 2: The canals were filled with DiaRoot-BA (DiaDent Group International, Canada). Group 3: Biodentine (Septodont, Saint Maur des Fosses, France) solution was mixed with the capsule powder and condensed using pluggers. Instron was used to determine the maximum horizontal load to fracture the tooth, placing the tip 3 mm incisal to the cementoenamel junction. Mean values of the fracture strength were compared by ANOVA followed by a post hoc test. P < 0.05 was considered statistically significant. Results: No significant difference was observed among the MTA, BA, and biodentine experimental groups. Conclusion: All the three materials tested, may be used as effective strengthening agents for immature teeth.

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Biaxial flexural strength of different types of monolithic zirconia

Brazilian Dental Science ◽

10.14295/bds.2019.v22i1.1696 ◽

2019 ◽

Vol 22 (1) ◽

pp. Process

Author(s):

Shereen Ahmed Nossair ◽

Tarek Salah ◽

Kamal Khaled Ebeid

Keyword(s):

Flexural Strength ◽

Zirconia Ceramic ◽

Group 4 ◽

Dental Esthetics ◽

Biaxial Flexural Strength ◽

Different Types ◽

Monolithic Zirconia ◽

Group 5 ◽

Group 2 ◽

Post Hoc

Objective: This study was designed to evaluate the biaxial flexural strength (BFS) of different types of unshaded and shaded monolithic zirconia. Material and Methods: 120 monolithic zirconia ceramic discs were fabricated. They were divided into twelve groups (n=10), Group 1; Bruxzir unshaded, Group 2; Bruxzir shaded A2, Group 3; Bruxzir anterior white, Group 4; Bruxzir anterior shade A2, Group 5; Prettau unshaded, Group 6; Prettau shaded with A2 coloring liquid, Group 7; Prettau anterior white, Group 8; Prettau anterior shaded with A2 coloring liquid, Group 9; Katana HT white, Group 10; Katana HT shade A2, Group 11; Katana ST white, Group 12; Katana ST shade A2. All discs were milled using a dental milling machine, and had final dimensions after sintering of 15 mm diameter and 1 mm thickness. BFS was tested using piston on three ball technique. Results: One-way ANOVA revealed significant differences among the 12 groups. Tukey post-hoc tests revealed no significant differences between the groups 3, 4, ,7 ,8 11, and 12. However, they all had BFS values that are significantly lower than all other groups. Group 2 showed statistically significant higher BFS values when compared to group 3,4, 7, 8, 11, and 12 while it showed statistically significant lower values when compared to groups 1, 5, 6, 9, and 10. Conclusion: Increase in the yttria content in zirconia led to a decrease in its BFS. Shading of zirconia did not have a significant effect on the final strength of zirconia. KeywordsDental ceramics; Dental esthetics; Flexural strength; Shaded zirconia.

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Comparative evaluation of postoperative pain intensity after single-visit and multiple-visit retreatment cases: a prospective randomized clinical trial

Brazilian Dental Science ◽

10.14295/bds.2018.v21i1.1515 ◽

2018 ◽

Vol 21 (1) ◽

pp. 26 ◽

Cited By ~ 3

Author(s):

Hatice Miray Uyan ◽

Keziban Olcay ◽

Mutlu Özcan

Keyword(s):

Postoperative Pain ◽

Repeated Measures ◽

Control Group ◽

Periapical Lesions ◽

Single Visit ◽

Group 4 ◽

Multiple Visit ◽

Significant Difference ◽

Group 3 ◽

Group 2

Objective: This study was designed to evaluate postoperative pain after endodontic retreatment. Material and Methods: Asymptomatic, multi-rooted molar & premolar teeth requiring retreatment with 2–5 mm periapical lesions were included. Seventy-eight teeth were randomly placed in four groups (n=20): single-visit (control, group 1), Ledermix (group 2), metronidazole, ciprofloxacin, minocycline mixture (group 3), calcium hydroxide (group 4). The postoperative pain was recorded using a VAS at 6, 12, 24, and 48 h after retreatment. Statistical evaluation was performed using Two-Way Repeated Measures ANOVA and Tukey test. Results: Mild pain occurred in 67.5%, moderate in 30%, and flare-ups in 2.5%, and there was a significant difference between the groups (p<0.01). Significantly lower postoperative pain was observed in TAP and CaOH2 groups(p<0.05). In the 6, 12, and 24 h intervals, there was a significant difference in the pain levels (p<0.05). Conclusion: TAP and CaOH2 are effective for reducing postoperative pain after retreatment.KeywordsIntracanal medicaments; Multiple-visit; Postoperative pain; Retreatment; Single-visit.

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