Gallium Alloy Restorations in Primary Teeth: A 12 Month Study

Author(s): Kaga M, Nakajima H, Sakai T, and Oguchi H.
Journal: JADA
Volume (number): 127(1195-1200)
Month, Year: Aug 1996

Major topic: Gallium restorations marginal integrity and surface roughness
Minor topic(s: None

Type of Article: Research article

Main Purpose: This study evaluated the clinical performance and in-vivo corrosion resistance of a commercially available gallium alloy, Gallium Alloy GF)
Overview of method of research: 60 cavity preparations, 32 Class I and 28 Class V were restored. Three days after the restoration was polished. In patients with greater than 1 carious lesion, a gallium alloy was placed in 1 or 2 primary molars and the remaining carious lesions were restored with composite. In 6 patients with 2 or more carious lesions, amalgam was placed in mandibular second primary molars and gallium in mandibular first primary molars. Restorations were evaluated for surface appearance and marginal integrity, post operative sensibtivity, secondary caries and tooth fracture at 4, 8, and 12 months. After exfoliation some of these teeth were evaluated using a scanning electron microscopy for tooth structure and component elements.

Findings: At 4 months, 81% of Class 1 rstorations were rated B or C for surface appearance and deteriorated until about 8 months. Between 8 and 12 months there was no statistical change. The Class V restorations had significantly better surface appearance then the Class 1 restorations. When compared to amalgam the gallium restorations had much more corrosion and surface roughness. The authors suggested that this deterioration in the Class 1 restorations was related to the wear related to occlusal forces. Also palladium from gallium restorations has greater corrosion properties then the metals in amalgam.
Marginal integrity fared better for gallium. 69% of Class 1 restorations were rated A and decreased gradually to 59% at 12 months. Class V restoration had better marginal integrity throughout the study.

Key points/Summary : Surface corrosion must be improved before it can be accepted as an acceptable alternative to amalgam. The surface appearance which includes corrosion deteriorated significantly in chemical settings. The benefits include elimination of exposure of mercury to children and staff, and ease of placement over composites.

Assessment of article: Well presented article that shows that gallium alloy is inferior to current treatment modalities.