Cement Selection for Cement-Retained Implant-Supported Prostheses: A Literature Review

Prediction of excess cement residues using a regression model to avoid peri-implant diseases: An in vitro study

Dental implant restorations attached to cement can potentially result in peri-implant mucositis and peri-implantitis if cement residues are present. Effectively predicting and eliminating such dental cement residues is crucial for preventing complications. This study focuses on creating a regression model using the pixel values to predict the Excess Cement Residues (ECR) by employing an octagonal surface imaging approach. A model featuring gingival imitation, ten abutments, and ten crowns was created, and the cemented implants underwent thorough photographic and analytical assessment. The ECR was determined through two distinct approaches: the Computerized Planimetric Method (CPM) and the weighing method. Across ten implants in this in vitro study, ECR varied from 0.3 to 21 mg, with an average of 5.69 mg. The findings reveal a higher amount of ECR on the distal, mesiobuccal, and mesial sides. Utilizing Pearson's correlation, a coefficient value of r = 0.786 signifies a strong correlation between CPM and the weighing method. The regression model further aids in predicting ECR based on pixel values. The octagonal surface imaging approach not only vividly captures information about ECR in the implant cementation region but also emphasizes the feasibility of ImageJ as an effective tool for detecting ECR. The congruence between CPM and the weighing method results supports the application of the regression model for precise ECR prediction.

Clinical effect of Nobel Biocare angulated screw channel crown compared with cement crown in the aesthetic area: A retrospective cohort study with a mean 32 months follow-up (range 12 to 70 months)

OBJECTIVE

The objective of this study is to compare the clinical efficacy of angulated screw channel abutment applied in the anterior area with regular cemented crowns.

MATERIALS AND METHODS

Forty-eight patients were included and divided into two groups: the angulated screw channel group (ASC) and regular cemented group (RC) in this retrospective cohort study. The evaluation criteria included implant/restoration survival rate, keratinized mucosa width (KMW), bleeding on probing rate (BOP%), probing depth (PD), pink aesthetic score (PES), mechanical/biological complications, emergence angle (EA), the site of implant axis penetrate (SA), marginal bone loss (MBL), and buccal bone thickness (BBT) at 0 mm, 1 mm, 3 mm, 5 mm below the implant shoulder were evaluated in immediate postoperative (T0) and follow-up period (T1).

RESULTS

This retrospective cohort study included a total of 48 patients, with a mean 32 months follow-up period range from 12 months to 70 months. The study did not find any cases of implant failure or restoration failure. EA was significantly wider in the RC group than ASC group (RC: 33.53° ± 8.36° vs ASC: 27.43° ± 8.08°, p = 0.016*). While the BOP% was statistically significant higher in the RC group than ASC group (RC: 28.35% ± 22.92% vs ASC: 13.18% ± 20.00%, p = 0.027*). No significant differences were observed in the other measurements of comparison.

CONCLUSION

Within the limitations of the study, angulated screw channel (Nobel Biocare) crowns might allow the implant axis aim at incisal edge to reduce the emergence angle in the anterior area and benefit the soft-tissue during the 12-70 months follow-up period.

Effect of Restoration Design on the Removal Torque Loss of Implant-supported Crowns after Cyclic Loading

AIM

To compare the removal torque loss (RTL) percentage of screw-retained, cement-retained, and combined screw- and cement-retained implant-supported crowns after cyclic loading and measure the impact of cyclic loading on removal torque.

MATERIALS AND METHODS

Thirty-two dental implants (4.0 × 10 mm) in resin blocks and abutments were divided into four groups (n = 8) based on restoration design: combined screw- and cement-retained group (SC), two cement-retained groups: cemented with adhesive resin cement (AR) (Panavia V5) or provisional cement (PR) (RelyX Temp NE), and screw-retained one-piece titanium group (TI). Removal torques were measured in Newton-centimeter (Ncm) before and after 500,000-cycle cyclic loading with forces ranging from 20 to 200 N at 15 Hz. The RTL percentage in each group was calculated. The paired t-test was used to detect the difference between pre-loading (RT1) and post-loading removal torque (RT2) in each group and 1-way ANOVA was used to detect the difference of RTL percentage between groups.

RESULTS

The post-loading removal torques in all groups were significantly lower than their pre-loading removal torques (p < 0.001). The 1-way ANOVA test found no significant difference in the RTL% between the study groups. The PR group exhibited the lower RTL% (30.74 ± 7.3%), followed by the TI (30.78 ± 5.6%), AR (32.12 ± 2.5%), and SC (35.71 ± 5.1%) groups.

CONCLUSION

Combined screw- and cement-retained restorations exhibited similar RTL compared with other restoration designs, and cyclic loading significantly affected the removal torque.

CLINICAL SIGNIFICANCE

Combined screw- and cement-retained restorations can be utilized in single-tooth situations, offering a comparable impact on screw joint stability while providing benefit of retrievability. Cyclic loading significantly influences joint stability, periodic checkup for screw loosening is recommended. How to cite this article: Jongsiri S, Arksornnukit M, Homsiang W, et al. Effect of Restoration Design on the Removal Torque Loss of Implant-supported Crowns after Cyclic Loading. J Contemp Dent Pract 2023;24(12):951-956.

How can excess residual cement be reduced in implant-supported restorations?: An in vitro study

OBJECTIVE

The aim of this study was to investigate the effect of different cements and cementation techniques used in implant-supported restorations and the application of various vent modifications and extraoral replica techniques on the amount of overflowing cement in cemented systems.

MATERIALS AND METHODS

In this study, three different abutment designs were used as fully closed, occlusal vented, and occlusal + proximal vented. An extraoral replica was produced by milling the CAD/CAM ceramic block. The number of groups with and without replicas was determined as six (n = 10). For the cementation procedures, three different cements were tested: dual-cure resin, eugenol-free zinc oxide, and polycarboxylate cements. Cobalt-chromium superstructures to be cemented to the implant analog-abutment complex were produced by direct metal laser sintering method. Twenty-four hours after the cementation process, residual cement were measered with Micro-CT. In comparisons between groups, ANOVA test was used for normally distributed variables and Kruskall-Wallis H test was used for non-normally distributed variables at a significance level of p < 0.05.

RESULTS

The difference in residual cement volumes between the groups in terms of both cementation techniques (whether or not to use an extraoral replica and different vent desings) and cement types was found to be statistically significant (p < 0.05). There was significantly less residual cement in all groups that used extraoral replicas than those that did not. As for the cement types, the most residual cement occurred in the resin cement.

CONCLUSION

The use of extraoral replicas and vent designs on the abutment significantly reduces the amount of residual cement. Regardless of the cementation technique, the type of cement used affects the amount of excess cement.

CLINICAL RELEVANCE

To reduce residual cement, both the type of cement and the cementation technique used must be considered.

Effect of hemispherical dimples at titanium implant abutments for the retention of cemented crowns

PURPOSE

The aim of this study was to assess the effect of hemispherical dimple structures on the retention of cobalt-chromium (Co-Cr) crowns cemented to titanium abutments, with different heights and numbers of dimples on the axial walls.

MATERIALS AND METHODS

3.0-mm and 6.0-mm abutments (N = 180) and Co-Cr crowns were prepared. The experimental groups were divided into two and four dimple groups. The crowns were cemented by TempBond and PANAVIA F 2.0 cements. The retention forces were measured after thermal treatments. A two-way Analysis of Variance (ANOVA) and post-hoc Tukey HSD test were conducted to analyze change in retention forces by use of dimples between groups, as well as t test for the effect of abutment height change (α = .05).

RESULTS

Results of the two-way ANOVA showed a statistically significant difference in retention force due to the use of dimples, regardless of the types of cements used (P < .001). A significantly higher mean retention forces were observed in the groups with dimples than in the control group, using the post hoc Tukey HSD test (P < .001). Results of t test displayed a statistically significant increase in the retention force with 6.0-mm abutments compared with 3.0-mm abutments (P < .001). The groups without dimples revealed adhesive failure of cements, while the groups with dimples showed mixed failure of cements.

CONCLUSION

Use of hemispherical dimples was effective for increasing retention forces of cemented crowns.

A Systematic Review of Cementation Techniques to Minimize Cement Excess in Cement-Retained Implant Restorations

Background: The most used types of retention of implant-supported prostheses are screw-retained or cement-retained restorations. The advantages and disadvantages of both have been identified by various authors over the years. However, cement-retained implant crowns and fixed partial dentures are among the most used types of restorations in implant prostheses, due to their aesthetic and clinical advantages. When cemented prostheses are made on implants, the problem of cement residues is important and often associated with biological implant pathologies. The objective of this research was to establish to what extent the techniques to reduce excess cement really affect the volume of cement residues. Materials and Methods: This review was written following the PRISMA statement; a detailed search was carried out in three different electronic databases—PubMed, Scopus, and Cochrane Library. The inclusion criteria were prospective clinical studies, with at least 10 participants per group, and with at least 6 months of the follow-up period. Results: There have been many proposals for techniques supposed to reduce the amount of excess cement in the peri-implant sulcus and on the prosthetic components, but of these, which are exceptional in their in vitro capabilities, very few have been clinically validated, and this represents the real limitation and a great lack of knowledge regarding this topic. Three articles met the inclusion criteria, which were analyzed and compared, to obtain the information necessary for the purposes of the systematic review. Discussion: Extraoral cementation can reduce the excess cement, which, after a normal excess removal procedure, is, nevertheless, of such size that it does not affect the possibility of peri-implant pathologies developing. All these studies concluded that a small amount of cement residue is found in the gingival sulcus, and using eugenol-free oxide cements, the residues were only deposited on the metal surfaces, with a better peri-implant tissues health. Conclusion: Despite the limitations of this study, it was possible to carefully analyze these characteristics and obtain valuable suggestions for daily clinical practice. Resinous cements are considered, due to the free monomers present in them, toxic for the soft tissues. The provisional zinc-oxide cements, also eugenol-free, represent the ideal choice. The different grades of retentive forces provided by these cements do not seem to have clinical effects on the decementation of restorations.

Comparing effectiveness of rubber dam and gingival displacement cord with copy abutment in reducing residual cement in cement-retained implant crowns: A crossover RCT

OBJECTIVE

To evaluate the amount of residual cement after cementation of implant crown abutments with rubber dam and retraction cord with copy abutments techniques.

MATERIAL AND METHODS

Thirty single posterior metal-ceramic implant-supported restorations were delivered to 20 patients. The crowns were fabricated with occlusal openings obturated with composite, and then luted with resin-reinforced glass-ionomer cement on customised standard abutments. The cementation procedure was performed twice in the same specimens using rubber dam (group 1) and retraction cord with copy abutment (group 2). If no cement remnants were seen on periapical radiographs after cleaning, the crown-abutment unit was dismounted. All quadrants of the specimens were photographed to calculate the percentage proportions of residual cement area. Mann-Whitney and Kruskal-Wallis tests were used for statistical analysis.

RESULTS

In each group, 120 measurements were performed (30 implants, 4 surfaces each). The median percentage ratio with interquartile range (IQR) between the cement remnant area and total specimen area was 1.39% (IQR 0.77%-2.29%) and 0.58% (IQR 0.31%-1.33%) in groups 1 and 2, respectively. Lesser cement remnants were found in group 2 with a statistically significant difference (p < .001). The comparison of the mesial, distal, buccal, and lingual surfaces in each group showed no statistically significant differences between them (group 1, p = .482; group 2, p = .330).

CONCLUSIONS

The retraction cord and copy abutment reduced the excess cement more efficiently than the rubber dam did. Notwithstanding, undetected cement remnants were observed with both methods, and neither should be considered reliable in clinical applications.

The influence of two different cements on remaining cement excess in cement-retained implant-supported zirconia crowns. An in vitro study

Aim

To compare the amount of remaining cement excess after cementation of implant-supported zirconia crowns with zinc phosphate or calcium aluminate glass ionomer cement.

MATERIALS AND METHODS

Twenty zirconia crowns were cemented on dental implant abutments using a calcium aluminate glass ionomer cement (n = 10) and zinc phosphate cement (n = 10). After removal of cement excess, remaining cement excess were measured with pixel area calculation method and by weighing. Differences in amount of remaining cement excess were analyzed using Independent Samples t-Test. Level of significance was set at p = 0.05.

Results

Zinc phosphate cement had a significantly greater amount of remaining cement excess than calcium aluminate glass ionomer cement in terms of total number of pixels (p = 0.002) and amount in grams (p = 0.005).

Conclusion

The study suggests that the amount of remaining cement excess can be affected by the type of cement. Calcium aluminate glass ionomer cement may be a more suitable choice for cement-retained dental implant restorations, and possibly reduce the risk of complications related to cement excess such as peri-implant disease. Further studies are needed to verify the results from the present study.

Management of unfavorable implant positions and angulations in edentulous maxillae with different complete-arch fixed prosthetic designs: A case series and clinical guidelines

Implant-supported fixed prostheses in the edentulous maxilla can be difficult because of anatomic limitations and high esthetic demand. The choice between cement and screw retention depends on factors such as esthetics, occlusion, retrievability, and passivity. The choice is also often governed by the ability to manage technical or biologic complications. In the edentulous maxilla, because of the bone trajectory and resorption pattern, unfavorable implant angulations may be encountered. In such situations, a conventional screw-retained prosthesis is difficult to design. This article describes the restoration of edentulous maxillae for a series of patients with different complete-arch fixed prosthesis designs. The clinical guidelines, including indications, advantages, and limitations of each design, were discussed.

A Modified Technique for Fabricating Customized Angled Dual Abutments for Implants with Severe Angulations

Ideally, dental implants should be placed parallel to each other and perpendicular to the occlusal forces. However, they might be implanted with undesirable angulations due to anatomic limitations such as proximity to infra alveolar nerve or maxillary sinus or dentist incompetency. Improper angulation is often addressed at the prosthetic stage of the treatment via using angled abutments. However, severely angled implants could be more challenging regarding the restoration of both esthetics and function. This article presents a cost effective, simple and practical method for fabricating customized angled abutments for restoring severely angled abutments.

Effect of different surface treatments on the shear bond strength of luting cements used with implant-supported prosthesis: An in vitro study

PURPOSE

The aim of this study was to investigate the shear bond strength of luting cements used with implant retained restorations on to titanium specimens after different surface treatments.

MATERIALS AND METHODS

One hundred twenty disc shaped specimens were used. They were divided into three groups considering the surface treatments (no treatment, sandblasting, and oxygen plasma treatment). Water contact angle of specimens were determined. The specimens were further divided into four subgroups (n=10) according to applied cement types: polycarboxylate cement (Adhesor Carbofine-AC), temporary zinc oxide free cement (Temporary Cement-ZOC), non eugenol provisional cement for implant retained prosthesis (Premier Implant Cement-PI), and non eugenol acrylic-urethane polymer based provisional cement for implant luting (Cem Implant Cement-CI). Shear bond strength values were evaluated. Two-way ANOVA test and Regression analysis were used to statistical analyze the results.

RESULTS

Overall shear bond strength values of luting cements defined in sandblasting groups were considerably higher than other surfaces (P<.05). The cements can be ranked as AC > CI > PI > ZOC according to shear bond strength values for all surface treatment groups (P<.05). Water contact angles of surface treatments (control, sandblasting, and plasma treatment group) were 76.17° ± 3.99, 110.45° ± 1.41, and 73.80° ± 4.79, respectively. Regression analysis revealed that correlation between the contact angle of different surfaces and shear bond strength was not strong (P>.05).

CONCLUSION

The retentive strength findings of all luting cements were higher in sandblasting and oxygen plasma groups than in control groups. Oxygen plasma treatment can improve the adhesion ability of titanium surfaces without any mechanical damage to titanium structure.

Reconstruction of a Mandibular Defect with Toronto Bridge Following Tumor Resection and Bone Graft: A Case Report

Dental implants are highly recommended to improve the retention, stability, and support of prostheses in edentulous patients with large surgical defects. Depending on the size of the defect, a bone graft procedure might be necessary. However, due to limitations of bone grafts, some complications might negatively affect the prosthetic rehabilitation of the patient. This case report presents some of these prosthetic problems following surgical resection and autogenous bone graft procedures.

Cement shield membrane technique to minimize residual cement on implant crowns: A dental technique

Residual cement around implant crowns can cause peri-implant disease, which can be minimized by precementing on a copy abutment. This article describes the use of polytetrafluoroethylene (PTFE) tape to allow an intraorally delivered custom or stock abutment to act similar to a copy abutment. It requires minimal change to the restorative dentist's routine and helps minimize the risk of cement-induced peri-implant disease.

Influence of Luting Materials and Methods and the Restoration Surface on the Amount of Cement Remnants in Implant Restorations

This study aimed to investigate the effects of the luting methods on the amount of cement remnants in implant restorations and to determine the restoration surface with the maximum amount of residual cement. Forty abutments and crowns were divided into 4 groups as follows: TB group, luting with zinc oxide-eugenol cement; TBV group, luting with zinc oxide-eugenol cement after application of a separating agent over the transmucosal area of the abutment; PI group, luting with methacrylate cement; and PIV group, luting with methacrylate cement after application of a separating agent. After cementation, all the quadrants of the specimens were photographed, and the amount and location of the cement remnants were statistically analyzed (P ≤ .05). The amount of cement remnants was significantly smaller in the groups with a separating agent. The type of luting material did not significantly affect the results. Cement remnants were more abundant on the mesial and distal sides than on the buccal and lingual sides of the restoration.

Detection of Residual Excess Zinc Oxide–Based Cement With Laser Fluorescence (DIAGNOdent): In Vitro Evaluation

Because of its importance in the development of peri-implant mucositis and peri-implantitis, detection of residual excess cement (REC) is often the focus of studies addressing cement-retained implant-supported restorations. The purpose of this study was to evaluate the sensitivity and specificity of laser fluorescence (DIAGNOdent) for detecting residual excess zinc oxidebased cement around dental implants. In this in vitro study, 15 tissue-level implants were embedded in acrylic resin. To simulate gingiva around the implants, the transgingival part of each implant was covered with a gingival mask silicon material. Cement (Tempobond; 1 × 1 × 1 mm) was applied to 30 areas, 4 mm below the gingival-mimicking line using a custom-made template. A DIAGNOdent laser device was used by 2 independent examiners to evaluate the presence or absence of cement in a selected area. The examiners were allowed to probe the gingival sulcus (2-mm depth) 2 times with a 5-minute interval between tests. The residual cement was recognized by gently walking the device tip around the implant. A detection score less than 16 indicated an absence of cement, and scores of 16 or greater indicated the presence of excess luting agent in the implant sulcus. The sensitivity and specificity of DIAGNOdent to detect REC in the sulcus were 100% and 96.67%, respectively. Based on our findings, we propose that DIAGNOdent could be used to detect REC in the sulcus of cement-retained implant supported restorations.

Influence of Luting Materials on the Retention of Cemented Implant-Supported Crowns: An In Vitro Study

The retention force of cemented crowns on implant abutments with various luting materials was evaluated. Cobalt⁻chromium crowns were cemented onto tapered titanium abutments (Camlog) with eugenol-free temporary cement (RelyX TempBond NE), composite-based temporary cement (Bifix Temp), zinc phosphate cement (Harvard Cement), glass-ionomer cements (Meron, Fuji I), and resin-modified glass-ionomer cements (Fuji II, Fuji Plus, Ketac Cem Plus). Specimen aging via hydrostress was performed in artificial saliva at 37 °C for 14 days (S1), followed by hydrothermal stress with thermocycling (S2). The crowns were removed, and the force was recorded (T1). Subsequently, the crowns were recemented, aged, and removed, and the force was recorded (T2, T3). The retention forces differences were statistically significant according to the storage conditions at T1 (p = 0.002) and T3 (p = 0.0002). After aging (S1), Ketac Cem Plus had the highest retention force median value difference (T3 versus T1) (-773 N), whereas RelyX TempBond NE had the lowest (-146 N). After aging (S2), Meron had the highest retention force median value difference (-783 N), whereas RelyX TempBond NE had the lowest (-168 N). Recementation decreased the retention force of the implant-supported cobalt⁻chromium crowns cemented and recemented with the same luting materials. Luting materials (at T1) and aging conditions significantly impacted the retention force.

The Effect of Milling Metal Versus Milling Wax on Implant Framework Retention and Adaptation

PURPOSE

The metal framework of implant-supported restorations can be made using different methods. For a successful outcome, the acceptability of each method depends on the retention and fit of the restoration. The aim of this study was to evaluate and compare the retention and adaptation of copings fabricated using two methods: casting wax patterns made by computer-aided design/computer-aided manufacturing (CAD/CAM) technology, and milling sintered chromium-cobalt (Cr-Co) blocks.

MATERIALS AND METHODS

Twenty-four abutment analogs (height, 5.5 mm) were divided into two groups according to the framework fabrication method. In one group, wax patterns were prepared using a CAM milling machine, and they were cast with a Ni-Cr-Ti metal alloy. In the second group, the copings were milled from Cr-Co blocks using a CAD/CAM milling machine. All copings were equal in contour, thickness, and internal relief and were seated on the abutment analogs after the necessary adjustments. The vertical marginal discrepancy was investigated using a silicone replica method and stereomicroscope with 75× magnification. After copings were cemented onto the abutment analogs using zinc phosphate, a tensile resistance test was performed using a universal testing machine. Mann-Whitney U and Student's t-test were used for statistical analyses at a significance level of 0.05.

RESULTS

An independent sample t-test revealed a significant difference between the two groups for retention (p = 0.010), and the milled wax group showed higher tensile resistance compared with the milled metal group. There was also a significant difference between the two groups in marginal discrepancy (p < 0.001), with a larger marginal gap in the milled metal group compared with the milled wax group. The milled metal copings required more adjustments to fit on the abutment analogs compared with the wax milled copings (p < 0.001).

CONCLUSIONS

The CAD/CAM technique for wax milling resulted in more retentive copings with better marginal and internal adaptations compared with milling the metal blocks.

Influence of cement type and ceramic primer on retention of polymer-infiltrated ceramic crowns to a one-piece zirconia implant

STATEMENT OF PROBLEM

The best procedure for cementing a restoration to zirconia implants has not yet been established.

PURPOSE

The purpose of this in vitro study was to measure the retention of polymer-infiltrated ceramic crowns to zirconia 1-piece implants using a wide range of cements. The effect of ceramic primer treatment on the retention force was also recorded. The retention results were correlated with the shear bond strength of the cement to zirconia and the indirect tensile strength of the cements to better understand the retention mechanism.

MATERIAL AND METHODS

The retention test was performed using 100 polymer-infiltrated ceramic crowns (Vita Enamic) and zirconia implants (ceramic.implant CI) The crowns were cemented with either interim cement (Harvard Implant semipermanent, Temp Bond), glass-ionomer cement (Ketac Cem), self-adhesive cement (Perma Cem 2.0, RelyX Unicem Automix 2, Panavia SA), or adhesive cement (Multilink Implant, Multilink Automix, Vita Adiva F-Cem, RelyX Ultimate, Panavia F 2.0, Panavia V5 or Panavia 21) (n=5). Additionally ceramic primer was applied on the intaglio crown surface and implant abutment before cementation for all adhesive cements (Multilink Implant, Multilink Automix: Monobond plus; RelyX Ultimate Scotchbond Universal; Vita Adiva F-Cem: Vita Adiva Zr-Prime; Panavia F2.0, Panavia V5: Clearfil Ceramic Primer) and 1 self-adhesive cement containing 10-methacryloyloxydecyl dihydrogen phosphate (MDP) (Panavia SA: Clearfil Ceramic Primer). Crown debond fracture patterns were recorded. Shear bond strength was determined for the respective cement groups to polished zirconia (n=6). The diametral tensile strength of the cements was measured (n=10). Statistical analysis was performed using 1-way or 2-way analysis of variance followed by the Fisher LSD test (α=.05) within each test parameter.

RESULTS

Adhesive and self-adhesive resin cements had shear bond strength values of 0.0 to 5.3 MPa and revealed similar retention forces. Cements containing MDP demonstrated shear bond strength values above 5.3 MPa and displayed increased retention. The highest retention values were recorded for Panavia F 2.0 (318 ±28 N) and Panavia 21 (605 ±82 N). All other adhesive and self-adhesive resin cements attained retention values between 222 ±16 N (Multilink Automix) and 270 ±26 N (Panavia SA), which were significantly higher (P<.05) than glass-ionomer (Ketac Cem: 196 ±34 N) or interim cement (Harvard Implant semipermanent: 43 ±6 N, Temp Bond: 127 ±13 N). Application of manufacturer-specific ceramic primer increased crown retention significantly only for Panavia SA.

CONCLUSIONS

Products containing MDP provided a high chemical bond to zirconia. Self-adhesive and adhesive resin cements with low chemical bonding capabilities to zirconia provided retention force values within a small range (220 to 290 N).