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.
Key points
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A wide variety of dental cements are commercially available to retain an implant-supported prosthesis. Each cement material has certain characteristics and properties.
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Retention of dental cements for implant-supported prosthesis varies from tooth-supported prosthesis. Retention and esthetics are the main factors in cement selection guideline.
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Peri-implant mucositis and peri-implantitis are major concerns when considering cement-retained implant prosthesis. It is customary to use different cementation techniques to minimize excess cement.
Introduction
Cement-retained implant-supported prostheses (CRISP) have been commonly used because of simplicity and cost effectiveness. Peri-implant health parameters were reported to be similar around screw-retained and cement-retained prosthesis, provided that excess cement is removed. Although the fabrication of cement-retained prostheses is simple and similar to tooth-borne prostheses, the retention of dental cements varies between CRISP and tooth-supported prostheses. A survey by Tarica and colleagues (2010) showed that resin-modified glass ionomer (GI) is the most preferred cement for CRISP in United States dental schools. The second most popular cement is zinc oxide eugenol (ZOE), followed closely by GI. Polycarboxylate (PCB) and acrylic urethane were the least used materials. This article will shed light on the characteristics of dental cements used in implant dentistry. It also provides selection criteria according to the material of the abutment and prosthesis.
Characteristics of an ideal cement
An ideal cement should have the following characteristics:
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Biocompatibility
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Adequate mechanical characteristics
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Promotion of tissue health
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Adequate marginal seal
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Dissolution resistance
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Radiopacity
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Excellent esthetics
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Cost effectiveness
An ideal cement is yet to be developed. The clinicians’ preference and clinical situation are the currently used selection criteria.
Dental cement materials
Several classification systems categorize cements based on characteristics such as composition and chemical bonding properties. The classification of dental cements for cementing prostheses to natural abutments does not necessarily apply to implant-supported prostheses. For instance, whereas (ZOE) is used for short-term cementation during provisionalization on teeth, ZOE provides sufficient retention for CRISP. Because this article focuses on clinical applications, it is appropriate to classify dental cements as either provisional, semipermanent, or permanent ( Table 1 ).
| Provisional | Semipermanent | Permanent |
|---|---|---|
| Zinc oxide eugenol Eugenol-free zinc oxide |
Zinc phosphate Glass ionomer |
Resin-modified glass ionomer Zinc polycarboxylate Resin cement |
Provisional cements
Provisional cements are highly soluble and show weak tensile strength. This may be advantageous when completing a provisional CRISP or recementing a prosthesis that is associated with peri-implantitis. Provisional cements allow for the retrievability of CRISP. However, CRISP may lose retention when provisional cement is used. Both ZOE and eugenol-free ZnO (EF-ZnO) are considered provisional cements. According to Ma and Fenton’s systematic review, 17.6% loss of retention of CRISP occurred when provisional cements were used. The characteristics of ZOE and EF-ZnO are addressed in Table 2 .
| Cement Type | Characteristics | Advantages | Disadvantages |
|---|---|---|---|
| ZOE |
|
|
|
| Eugenol-free zinc oxide |
|
|
|
Semipermanent cements
Semipermanent cements provide sufficient retention to resist frequent decementation and allow retrievability. Zinc phosphate (ZnP) and GI are considered semipermanent cements when used with CRISP. Semipermanent cements reduce the incidence of decementation when compared with provisional cements. When a cement’s tensile strength is between provisional and permanent cements, it is classified as a semipermanent cement. A permanent cement, such as resin cement, can be made semipermanent by mixing it with petroleum jelly. ZnP and GI offer a degree of retrievability when used with titanium or zirconia abutments. Wittneben and Bragger’s systematic review demonstrated a decementation rate of 0% for CRISP cemented with ZnP. Table 3 provides an overview of ZnP and GI characteristics.
| Cement Type | Characteristics | Advantages | Disadvantages |
|---|---|---|---|
| ZnP |
|
|
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| GI |
|
|
|
Permanent cements
After careful evaluation of peri-implant tissue health, clinicians may wish to cement the prosthesis indefinitely. Permanent cements should have characteristics that prohibit the occurrence of any prosthetic complication. It must allow for long-term retention, peri-implant health and a desirable esthetic outcome. Resin-modified GI (RMGI), zinc PCB, and resin cements share properties of permanent cements. RMGI, PCB, and resin are used to retain permanent CRISPs. A systematic review by Chaar and colleagues revealed a decementation rate up to 4% for CRISP retained with permanent cements ( Table 4 ).
| Cement Type | Characteristics | Advantages | Disadvantages |
|---|---|---|---|
| RMGI |
|
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| Zinc PCB |
|
|
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| Resin |
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