Aluminum Oxide Sandblasting of Hexagonal Coping and Abutment: Influence on Retention and Marginal Leakage Using Temporary Cements

Impact of cement type and abutment height on pull-off force of zirconia reinforced lithium silicate crowns on titanium implant stock abutments: an in vitro study

Background

Pull-off forces of cement-retained zirconia reinforced lithium silicate (ZLS) in implant-supported single crowns on stock titanium abutments with respect to abutment height and implant cement were evaluated and compared.

Methods

Pull-off force of ZLS crowns on stock titanium abutments was evaluated concerning dental cement and abutment height. A total sample size of 64 stock abutments with heights of 3 mm (n = 32) and 5 mm (n = 32) was used. The ZLS crowns were cemented with four different types of cement (one temporary, two semi-permanent, and one permanent). After cementation, water storage, and thermocycling each sample was subjected to a pull-off test using a universal testing machine.

Results

The temporary cement showed the least pull-off force regardless of abutment height (3/5 mm: means 6 N/23 N), followed by the semi-permanent methacrylate-infiltrated zinc oxide cement (28 N/55 N), the semi-permanent methacrylate-based cement (103 N/163 N), and the permanent resin composite cement (238 N/820 N). Results of all types of cement differed statistically significantly from each other (p ≤ .012). The type of implant cement has an impact on the pull-off force of ZLS crowns and titanium abutments.

Conclusions

Permanent cements present higher retention than semi-permanent ones, and temporary cements present the lowest values. The abutment height had a subordinate impact.

Retrospective comparison of posterior fixed dental prostheses supported by two different titanium abutments on tissue level implants

STATEMENT OF PROBLEM

Clinical studies comparing compatible computer-aided design and computer-aided manufacturing (CAD-CAM) titanium abutments (CAs) and original prefabricated 1-piece titanium abutments (PAs) for posterior fixed dental prostheses (FDPs) on Straumann Tissue Level (STL) implants are sparse.

PURPOSE

The purpose of this retrospective clinical study was to compare the performance of posterior FDPs supported by CAs and PAs on STL implants after a mean observation period of 7.2 years.

MATERIAL AND METHODS

Patients who received STL implants and posterior FDPs by using CAs or PAs between January 2002 and December 2012 and returned for follow-up between January 2017 and September 2018 were included in this study. Technical and biological complications of FDPs were examined and recorded. Radiographs were used for the measurement of marginal bone loss (MBL) of each implant. Variables, complication rates, and MBL of the 2 groups were analyzed by using a generalized estimating equation and multivariable linear mixed model.

RESULTS

Ninety-nine patients with 195 implants in the CA group and 75 patients with 143 implants in the PA group were included. The mean functional time of FDPs was 6.5 ±1.1 years for the CA group and 8.1 ±2.6 years for the PA group. No implant failure was noted in either group. The technical complication rate was 20.8% in the CA group and 26.3% in the PA group. Abutment screw loosening (ASL) was noted in the CA group (8.5%). The decementation rate was significantly higher in the PA group (14.1%) than that in the CA group (3.1%) (adjusted odds ratio=4.40, confidence interval=1.41 to 13.69, P=.011). No significant differences were found between the 2 groups in terms of the rates of ceramic chipping, peri-implantitis, peri-implant mucositis, or mean MBL.

CONCLUSIONS

Using CAs or PAs to support posterior FDPs on STL implants has no significant effect on the incidence rate of biological complications. However, a higher ASL rate and a lower decementation rate were noted with CAs than with PAs.

Effect of porcelain firing and cementation on the marginal fit of implant-supported metal-ceramic restorations fabricated by additive or subtractive manufacturing methods

STATEMENT OF PROBLEM

Adaptation between abutment and suprastructure plays a crucial role in the long-term success of implant-supported metal-ceramic crowns. Fabrication methods, the porcelain firing stage, and cementation techniques may affect the marginal adaptation between the crown and abutment. However, the information regarding this issue is sparse.

PURPOSE

The purpose of this in vitro study was to compare marginal fit after the fabrication of cobalt-chromium alloy copings, porcelain firing, and cementation of metal-ceramic restorations that were fabricated with computer-aided design and computer-aided manufacturing (CAD-CAM) milling and direct metal laser sintering techniques.

MATERIAL AND METHODS

Thirty straight tissue-level titanium abutments were screwed onto implant analogs. All specimens were embedded in acrylic resin and divided into 2 groups according to CAD-CAM milling and direct metal laser sintering fabrication of the metal coping. Fifteen cobalt-chromium implant-supported metal copings were fabricated by using the CAD-CAM milling technique and 15 by using the direct metal laser sintering technique. In both groups, marginal gap measurements between the cobalt-chromium copings and abutments were obtained before (T0) and after the placement of the ceramic veneer (T1) and after cementation (T2) by using a stereomicroscope with a magnification of ×40. The data were statistically evaluated by using 2-way ANOVA and the Tukey post hoc test (α=.05). A t test was used to determine whether there were significant differences between the fabrication techniques (α=.05).

RESULTS

A significant difference in the fabrication stages was found in the direct metal laser sintering group. The direct metal laser sintering coping group and porcelain applied direct metal laser sintering group had a statistically lower marginal gap value than the cemented direct metal laser sintering group (P=.021, P=.038). The direct metal laser sintering coping group had a lower marginal gap value than the CAD-CAM milling coping group, although the difference was not statistically significant (P=.216).

CONCLUSIONS

Porcelain firing and cementation increased the marginal gap between the crown and abutment. No statistically significant differences were found between the direct metal laser sintering and CAD-CAM milling techniques in terms of marginal fit.

Comparing the marginal leakage and retention of implant-supported restorations cemented by four different dental cements

BACKGROUND

Despite the wide use of implants in dentistry, there is insufficient information about the ideal cement for retention.

PURPOSE

To determine the cement bond strength and marginal leakage of crown and partial denture cemented to implant abutments by four different types of cement.

MATERIALS AND METHODS

Eighty-four direct abutments were divided into eight groups (n = 7). Fifty-six crown and bridge restorations were cemented using zinc phosphate (ZM), temporary cement (TM), resin-modified glass-ionomer cement (GM), and self-adhesive resin cement (RM). After cementation, thermal cycling and incubation in basic fuchsin dye was applied. The maximum load to failure, marginal leakage, and fracture modes were evaluated.

RESULTS

The mean of retention strength for the bridges (874 N) was higher than the crown samples (705 N) (P = .005). The mean of retention strength for each cement group was ZM = 1298, RM = 1027, GM = 646, and TM = 187 N (P ≤ .0001). Marginal leakage was recorded in majority of the samples; the highest incidence was detected for ZM samples. The cement fracture was mostly adhesive in nature.

CONCLUSION

Self-adhesive resin and resin-modified glass ionomer cement had better mechanical properties to retain implant supported restorations.

What is the Best Available Luting Agent for Implant Prosthesis?

Cement-retention is a viable option in restoring dental implants. A wide range of dental cements with different properties are commercially available for use in the cementation of implant prostheses. The selection of a dental cement for proper clinical application can be challenging. This article overviews the commercially available dental cements used in cement-retained implant-supported prostheses. Guidelines for cement selection are presented according to abutment and prosthetic material. Cementation techniques to reduce excess cement in peri-implant tissues are also mentioned.