To evaluate the mechanical properties and bacterial adhesion of the glass fiber-reinforced composite resin space maintainer.

The mechanical properties of the composite resin high-strength fiber (experimental group) and the band and loop type (control group) space maintainer were tested by universal material testing machine. The two types of space maintainer were placed on a plate with a strain of Streptococcus mutans. Scanning electron microscopy and viable cell counts were used to observe bacterial attachment.

There was no significant difference in the maximum shear resistance between the experimental group (32.02 ± 4.315) N and the control group (33.35 ± 5.154) N space maintainer (P>0.05). Scanning electron microscope showed that streptococcal bacteria were attached to the surface of the two groups. The colony count quantity of the experimental group (10.02 ± 2.315)×10⁴ CFU/mL was decreased compared with that of the control group (14.35 ± 2.154)×10⁴ CFU/mL. The difference was statistically significant (P < 0.05).

The composite resin high-strength fiber and the band and loop type space maintainer have comparable mechanical strength; however, the composite resin high-strength fiber bacteria adheres less than the band and loop type, and the self-cleaning function is relatively good.

To evaluate the fatigue resistances of glass fiber reinforced composite resin (GFRCR) space maintainers and to compare the fatigue resistance of GFRCR space maintainers made of two different kinds of composite resins.

40 extracted human molars were selected. Samples were randomly divided into two groups (n = 20). Space maintainers in group A were made of Z350 composite resin, while space maintainers in group B were made of Grengloo composite resin. All the specimens were exposed to temperature alternating between 5~55 ℃. Then they were placed on the cyclic loading machine to bear cyclic loading and the number of loading times were recorded. The results were compared with standard fatigue strength.

The fatigue resistances of two groups were higher than standard fatigue resistances (P＜0.001). The fatigue resistances of two kinds of space maintainers showed no difference (P = 0.886).

According to the fatigue resistances, GFRCR space maintainers can be clinically used. There were on differences between two kinds of materials in making GFRCR maintainers.