Space requirement of a prefabricated bar on two interforaminal implants: a prospective clinical study

Influence of the loading protocol and platform switching in two-implant bar-retained overdentures: 3-year results from a randomized controlled equivalence clinical trial

OBJECTIVES

To test the null hypothesis that vertical peri-implant bone level alterations (ΔIBL) are equivalent in immediately (IL) and 3-month post-placement (DL) loaded implants in mandibular implant overdentures (IODs) on two implants.

MATERIALS AND METHODS

Thirty-two patients receiving two interforaminal implants, one with a platform-switched and one with a platform-matching abutment were randomly assigned to the IL or DL group (allocation ratio 1:1). All implants were primarily splinted with chairside-customized bars, converting the existing removable complete dentures to IODs. Standardized radiographs were recorded. The influence of the loading protocol (IL vs. DL), implant platform (platform switched vs. platform matching), implant site (43 vs. 33), participant age (≤65 vs. >65 years), and definition of baseline (implant placement vs. implant loading) were analyzed, applying linear regression analyses (α = 0.05). The equivalence range was [-0.4; 0.4].

RESULTS

Three participants of the IL group were lost during follow-up. The overall mean ΔIBL was -0.96 ± 0.89 mm. The ΔIBL was equivalent in terms of the implant platform and implant site but not in terms of participant age (in favor of more elderly participants) and the loading protocol. A significantly smaller ΔIBL was observed in the IL when the baseline was considered to be implant placement (p = .017), but not when it was considered to be implant loading (p = .084).

CONCLUSION

Immediate loading of primary-splinted implants in two-implant bar-retained overdentures, seems beneficial relative to loading 3 months post-placement, with respect to ΔIBL. The ΔIBL were equivalent in terms of platform switching.

Use of an attachment system with angulated abutments and polyetheretherketone inserts to retain a maxillary overdenture: A clinical report

This clinical report describes the rehabilitation of a maxillary edentulous arch with a current overdenture attachment system with angulated prefabricated abutments and polyetheretherketone (PEEK) inserts. Prefabricated angulated abutments were used on previously and recently placed diverging implants, which enabled a common path of insertion for the overdenture to be established during fabrication.

[Clinical application of mandibular overdenture supported by a two-implant and interforaminal bar in an edentulous atrophic mandible]

Implant-overdenture supported by an interforaminal bar provides stability and is effective in an edentulous atrophic mandible. However, using this attachment requires precise planning from the restorative and surgical aspects to ensure a satisfying outcome. Consdering the feature and space requirements for bar attachment, this article establishes a clinical protocol for a two-implant-retained overdenture on the mandible. In this study, a case of mandibular edentulism was considered to illustrate this protocol and provide a reference for clinical practice.

Wear, microleakage and plastic deformation of an implant-supported chair-side bar system

PURPOSE

This in-vitro study was designed to evaluate retention forces, microleakage and plastic deformation of a prefabricated 2-implant bar attachment system (SFI-Bar, Cendres+Métaux, Switzerland).

MATERIALS AND METHODS

Two SFI implant-adapters were torqued with 35 Ncm into two implant analogues. Before the tube bars were finally sealed, the inner cavity of the tube bar was filled with liquid red dye to evaluate microleakage. As tube bar sealing agents three different materials were used (AGC Cem (AGC, resin based), Cervitec Plus (CP; varnish) and Gapseal (GS; silicone based). Four groups with eight specimens each were tested (GS, GS+AGC, AGC, CP). For cyclic loading, the attachment system was assembled parallel to the female counterparts in a chewing simulator. The mean retention forces of the initial and final ten cycles were statistically evaluated (ANOVA, α≤.05).

RESULTS

All groups showed a significant loss of retention forces. Their means differed between 30-39 N initially and 22-28 N after 50,000 loading cycles. No significant statistical differences could be found between the groups at the beginning (P=.224), at the end (P=.257) or between the loss of retention forces (P=.288). Microleakage occurred initially only in some groups but after 10,000 loading cycles all groups exhibited microleakage.

CONCLUSION

Long-term retention forces of the SFI-Bar remained above 20 N which can be considered clinically sufficient. The sealing agents in this study are not suitable to prevent microleakage.