Udod А.А., Chelyach Е.N.

Donetsk national medical university named M. Gorky, Ukraine

The Researching of Surface Roughness of New Resin-based Nanocomposite

In modern stomatology practice for the clinical estimation of quality of surface of restorations widely apply by-instrumental methods which do not contain quantitative information and depend on a number of factors. There are also laboratory methods of superficial profilometrii and profilografii for measuring of roughness of surface of resin-based composite (RBC), which it is impossible to apply in a clinic [1,2]. From other side, it is known that high-quality implementation of final treatment of restoration work is rendered by direct influence on aesthetic parameters, duration of functioning of restoration in the cavity of mouth, dental plaque, development of the second caries and diseases of parodontitis [3,4]. In this connection, the clinical estimation of quality of roughness of surface of RBC was developed by the computer analysis of digital representation of restorations, which, from our point of view, and is perspective direction in qualitylogy the grounded restoration treatment in stomatology (Udod А.А., Chelyach Е.N., 2007).

The aim of this study was to evaluate the effects differences in surface roughness of polishing system on a resin-based nanocomposite specimens on all stages of the study using computer analysis of digital view.

Materials and Methods.

We tested a new resin-based light-cured nanocomposite – Premise, 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	0,261±0,001	0,255±0,005
After finishing using diamond bur	0,204±0,001	0,203±0,001
After polishing PoGo, Dentsply	0,182±0,001	0,183±0,001

After polymerization the baseline surface roughening determining by profilography method of specimens Premise, Kerr, had a baseline surface roughness Ra=0,261±0,001 µm, using diamond bur provided a significantly smoother surface Ra=0,204±0,001 µm, than the baseline surface roughness of specimens and the statistically significantly smoothest surface has been provided by PoGo, Dentsply, Ra=0,182±0,001 µm. There was a statistically significant difference between data on all stages of first part of our study (р<0,05).

Using computer analysis we got the data of surface roughness after polymerization RBC’s specimens Ra=0,255±0,005 µm, then after finishing specimens surface with diamond bur we got a significantly smoother surface Ra=0,203±0,001 µm, but the statistically significantly smoothest surface has been got after polishing by PoGo, Dentsply, Ra=0,183±0,001 µm. There was a statistically significant difference between data on all stages of second part of our study (р<0,05).

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. Thus, the computer method of estimation of surface of RBC’s, based on the analysis of digital representation, allows to get these microroughness, comparable with the results of profilography, and allows in a clinic to estimate the degree of roughness of surface of RBC’s after polishing of restoration unlike profilography method.

Reference.

1. Başeren M. Surface roughness of nanofill and nanohybrid composite resin and ormocer-based tooth-colored restorative materials after several finishing and polishing procedures // Journal of biomaterials applications. – 2004. – Vol. 19, № 2. – P. 121-134.

2. Beun S., Glorieux T., Devaux J. et al. Characterization of nanofilled compared to universal and microfilled composites // Dental Materials. – 2007. – Vol. 23, Issue 1. – P. 51-59.

3. Mitra S.B., Wu D., Holmes B.N. An application of nanotechnology in advanced dental materials // Journal of American Dental Association. – 2003. – Vol. 134, № 10. – P. 1382-1390.

4. Koh R., Neiva G., Dennison J. et al. Finishing systems on the final surface roughness of composites // The Journal of Contemporary Dental Practice. – 2008. – Vol. 9, № 2. – Р. 138-145.