Comparative study of abutment screw loosening with or without adhesive material

Clinical and Radiographic Status and PISF Levels of PGE2 Around Cement and Screw Retained Implants

BACKGROUND

The aim was to assess the peri-implant clinicoradiographic status and prostaglandin E2 (PGE2) levels in peri-implant sulcular fluid (PISF) samples collected from individuals with cement-retained and crew-retained implants.

METHODS

In this observational study, participants with cement-retained and screw-retained implants were enrolled. A questionnaire was utilized to gather demographic information and assess the educational background of the participants. Peri-implant modified plaque and bleeding indices, probing depth, and crestal bone loss were measured. Subsequently, PISF samples were collected, and corresponding volumes were recorded. Commercial kits employing enzyme-linked immunosorbent assay were employed to quantify PGE2 levels. The sample size was determined, and group comparisons were conducted using the Student t test and the Mann-Whitney U-test. Logistic regression models were constructed to evaluate the correlation between PGE2 levels and clinicoradiographic and demographics. The predefined level of significance was established at P < .05.

RESULTS

Sixty-seven participants, consisting of 33 with cement-retained implants and 34 with screw-retained implants, were included in the study. The mean ages for individuals with cement and screw-retained implants were 54.2 ± 8.7 and 58.7 ± 7.4 years, respectively. The majority of participants had completed university-level education. Reportedly, 87.9% and 82.4% of individuals with cement and screw-retained implants, respectively brushed teeth twice daily. No significant differences were observed in clinicoradiographic parameters, PGE2 volume, and levels between cement-retained and screw-retained implants. There was no correlation between PGE2 levels and peri-implant clinicoradiographic parameters among individuals with either cement-retained or screw-retained implants.

CONCLUSIONS

Cement-retained and screw-retained implants exhibit a consistent peri-implant clinicoradiographic status, accompanied by stable levels of PGE2 in PISF provided oral hygiene maintenance regimens are stringently followed.

Anaerobic adhesives effect on counter-torque of abutment screws on implants with external hexagon and conical connections: An in vitro study

BACKGROUND

Abutment screw loosening is a common complication of implant supported prostheses, especially for single crowns. In engineering, anaerobic adhesives (AA) are used to provide chemical locking between screw surfaces, but their application in implantology remains unclear.

PURPOSE

The purpose of this article is to evaluate, in vitro, the effect of AA on counter-torque of abutment screws for cemented prosthesis on dental implants with external hexagon connection (EHC) and conical connection (CC).

MATERIALS AND METHODS

Sample was composed by 60 specimens, 30 dental implants with EHC and 30 with CC. Abutments (transmucosal 3 mm straight universal abutment) were installed without AA (control group) or with application of AA with two different adhesive strength: medium strength (LOCTITE® 242) and high strength (LOCTITE® 277). The specimens were subjected to mechanical cycling at 37°C, with a load setting of 133 N, a 1.3 Hz frequency, and 1 200 000 cycles. The abutments were removed, and the counter-torque values were registered. Screws and implants were inspected using a stereomicroscope to verify the presence of residual adhesive and damage the internal structures. The data were analyzed using descriptive statistics and comparison tests (p < 0.05).

RESULTS

Comparing to the torque of installation, the medium strength AA kept the counter-torque values for CC implants and the high strength AA kept the counter-torque for EHC implants and increased for CC implants. In the intergroup comparisons, control group presented significantly lower counter-torque values than other groups, both for EHC and CC implants. High strength AA presented similar results to medium strength AA in the EHC implants, but in the CC implants presented higher counter-torque values. Damage in threads was more frequent in the groups that received high strength AA.

CONCLUSION

The use of AA increased the counter-torque of abutment screws, both in implants with EHC and CC.

Effect of Application of a Bio-Adhesive on the Removal Torque Value and Rotational Misfit at the Implant-Abutment Junction: An In Vitro Study

The aim of this study was to assess the effect of application of a recently developed bio-adhesive (Impladhesive) to abutment screw threads on the removal torque value and rotational misfit at the implant–abutment junction. This in vitro study evaluated 20 implant fixtures and 20 straight abutments. Specimens were randomly divided into two groups (n = 10) with/without adhesive application. In the adhesive group, the abutment was dipped in Impladhesive before torquing. In the control group, the abutment was torqued conventionally without adhesive application. The removal torque value was recorded after completion of the cyclic loading of 500,000 cycles with 2 Hz frequency and 75 N load. Rotational misfit was recorded using a video measuring machine. After applying the torque, the change in the bisector angle on the abutment hex was recorded for each implant. The biocompatibility of Impladhesive was evaluated using a MTT cell vitality assay. Normal distribution of data was assessed using the Kolmogorov–Smirnov test. Data were analyzed using a t-test and Pearson’s correlation coefficient The application of Impladhesive at the implant–abutment interface resulted in significantly greater mean removal torque value compared to the control group (p = 0.008). In addition, the mean rotational misfit at the implant–abutment interface was significantly lower in the use of Impladhesive compared to the control group (p = 0.001). In addition, the cell vitality was found to be greater than 80% at all evaluated time points. It can be concluded that the application of Impladhesive on the abutment screw significantly decreased rotational misfit and increased the removal torque value. Future studies are needed to evaluate the efficacy of this bio-adhesive an in vivo setting.

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).

The Impact of Implant-Abutment Connection on Clinical Outcomes and Microbial Colonization: A Narrative Review

INTRODUCTION

Osseointegration are often suffering from oral conditions, especially, the micro gap at the implant-abutment connection represents a site for bacterial plaque aggregation, leading to increased inflammatory cells and causing peri-implantitis.

AIM

The aim of this narrative review was to describe the different kinds of implant-abutment connections and their ability to reduce bacterial leakage and thus prevent peri-implantitis.

MATERIALS AND METHODS

The following databases were consulted: Pubmed, Scopus, Cochrane Library, and Research gate and a total of 528 articles were found. After reading the abstract and titles, 473 items were excluded. The remaining articles (n = 55) were assessed for full-text eligibility. Thirty-three studies were included in the review.

RESULTS AND CONCLUSIONS

We selected 22 clinical trials and 11 reviews, examining a total sample of 2110 implants. From the review, it was clear that there exists a relationship between the implant-abutment interface and bacterial leakage. All the connections presented an amount of micro-gap and bacterial micro-leakage, though conical and mixed connection systems seemed to behave better. Moreover, both connections seemed to have a better load distribution and the mixed system also had anti-rotational properties which are very useful during the positioning of the prosthesis.