Udod А.А., Chelyach Е.N.

Donetsk national medical university named M. Gorky, Ukraine

The effect of Finishing on the Surface Roughness

of Universal Microhybrid Composite

The effectiveness of finishing and polishing procedures on composite surfaces is an important consideration in the restorative process. High quality finishing and polishing improves both esthetics and longevity of composite restorations; whereas rough, poorly polished surfaces contribute to staining, plaque accumulation, gingival inflammation, recurrent caries, and discoloration of the restoration. A highly polished surface of composite resin restorations is somewhat difficult to achieve. In adhesive restorations it is important to determine the best finishing/polishing technique to get the best results.

In modern dentistry is well-known visual and instrumental method of clinical estimation of restoration’s surface roughness, which doesn’t contain any quantity data and depends from different factors. There are laboratory methods of measurement of resin-based composite (RBC) surface roughness, these are profilography and profilometery, which are can’t made in clinic.

The aim of this study was to evaluate the effects differences in surface roughness of polishing system on an universal microhybrid composite specimens on all stages of the study using computer analysis of digital view.

Materials and Methods.

We tested an universal microhybrid resin-based light-cured composite – Point 4, Kerr (shade A2), and PoGo Polishing System, Dentsply. All specimen preparation, finishing and polishing procedures were done by the same investigator to reduce variability. It was prepared disk specimens 6 mm in diameter, 1,5 mm deep. Ten disks were fabricated. These specimens were polymerized for 20 seconds from the top and bottom surfaces using a Degulux, Degussa, light-curing unit. The samples were finished using diamond burs (size of diamond particulars is 30 µm, according to ISO) and polished using PoGo, Dentsply, according to the manufacturer’s instructions.

The average surface roughness in micrometers (Ra, µm) was measured on each specimen immediately after light curing, finishing by diamond burs and post-polishing using profilogphy method and presented computer analysis of digital view.

The surface roughness measurements were made for all the disks using a profilograph-profilometer, type AI, model 252. The record of microroughness was made on diagram tape with magnifications in horizontal line was 50, in vertical line was 2000. The average surface roughness on all stages of our study was calculated by taking the arithmetic mean roughness from the giving profilogrammes.

It was made a digital survey of each specimen investigating area by digital camera Canon Ixus 65 in «macro» regime. Digital views were saved keeping in JPEG. Using presented program product «Dental Quality» (Udod A.A., Shamaev V.V., 2007) we carried out an analysis of saving digital views. As a result of computer analysis we got data of surface microroughness of RBC’s specimen investigating area in micrometers.

Mean average surface roughness (Ra) was recorded in three stages: I stage – after polymerization, II stage – after finishing using diamond bur and III stage – after polishing PoGo, Dentsply.

Results. As a result of our researching had been got data of specimen’s surface roughening by profilography and computer analysis methods (table 1).

Table 1

The data of Point 4, Kerr, specimen’s surface roughening on all study stages

Study stages	Specimen’s surface roughening, µm
	Profilography method	Computer analysis method
After polymerization	0,411±0,002	0,409±0,003
After finishing using diamond bur	0,386±0,002	0,381±0,006
After polishing PoGo, Dentsply	0,360±0,005	0,357±0,006

After polymerization the baseline surface roughening determining by profilography method of specimens Point 4, Kerr, had a baseline surface roughness Ra=0,411±0,002 µm, using diamond bur provided a significantly smoother surface Ra=0,386±0,002 µm, than the baseline surface roughness of specimens and the statistically significantly smoothest surface has been provided by PoGo, Dentsply, Ra=0,360±0,005 µm. There was a statistically significant difference between data on all stages of first part of our study.

Using computer analysis we got the data of surface roughness after polymerization RBC’s specimens Ra=0,409±0,003 µm, then after finishing specimens surface with diamond bur we got a significantly smoother surface Ra=0,381±0,006 µm, but the statistically significantly smoothest surface has been got after polishing by PoGo, Dentsply, Ra=0,357±0,006 µm. There was a statistically significant difference between data on all stages of second part of our study.

There was no significant difference in data of all stages of our study between two different methods of surface roughness RBC’s specimens measuring (p>0,05).

Conclusion. In conclusion we can say that using computer analysis of digital view is allowed to take the data of surface roughness RBC’s specimens, which are compared with the results getting by profilography method, and carrying out an quantity estimation surface roughness of RBC after polishing procedures of restoration in clinic.