The purpose of the researchis comparative laboratory estimation of marginal bonding of nanomicro-hybrid material to the dental hard tissues in restoration of teeth with wedge-shaped defects under different curing time of acid etching. Object and methods of research. 30 patients, aged from 55 to 75, whose 30 teeth with wedge-shaped defects had to be extracted, have been examined. Before exodontia, enamel of all patients had been tested as for structur-al-functional acid resistance. After extraction, all teeth were divided into 3 groups. Group I included 10 teeth, which hard tissues of wedge-shaped defects were not etched before restoration, but were applied by the Xeno V, Dentsply self- etching dental adhesive; Group II included 10 teeth, which were etched during 30 seconds before application by the Prime & Bond, Dentsply self-priming dental adhesive; Group III included 10 teeth , which were etched during 60 seconds before application by dental adhesive. The EsthetX, Dentsply nanomicrohybrid material was applied for defects’ restora-tion. For artificial ageing of sealed teeth they were subjected to thermal cycling. To estimate the marginal bonding of photocomposite material to dental hard tissues a digital image of the zone, the material bonds to dental hard tissues, was performed on the perimeter of restoration, using the method of com-puter analysis of digital imaging in the condition of macro shooting by means of digital intraoral camcorder. Image analysis has been carried out by means of the «Dental Quality» software of house design. Then the samples of teeth were sawed lengthwise to be estimated as for micro permeability using the four-score system. The results were statistically processed by the Statistika 6,0 Windows 98 OS. Results of the research and their discussion. The study of tested structural-functional enamel acid resistance found that the average degree of acid resistance scored 2,97±0,17 in patients with teeth affected by wedge-shaped defects. The assessment of marginal bonding of photocomposite material to dental hard tissues on the perimeter of restoration by the method of computer analysis of digital imaging showed 20,00±12,65% of perfect bonding in samples from the Group I, bonding disorder up to 20% of the restoration perimeter was observed in 50,00±15,81% of cases, and bonding disorder not more than 50% of the restoration perimeter was observed in 30,00±14,49% of cases. In the samples of Group II perfect bonding was observed in 40,00±15,49% of cases, bonding disorder up to 20% of the restoration perimeter was observed in 40,00±15,49% of cases; and bonding disorder not more than 50% of the restoration perimeter was observed in 20,00±12,65% of cases (р>0,05). In the samples of Group III the indices were 60,00±15,49% and 40,00±15,49%, respectively (р>0,05). The difference between indices of the Group I and Group III is statistically significant (р<0,05). The study of marginal bonding of the restorative material to dental hard tissues on micro permeability found that the score of permeability disorder in samples of Group I constituted 2,40±0,17, in samples of Group II the score was 1,90±0,23 (р>0,05), and in samples of Group III the score was 1,20±0,13. The latter index statistically differs from the rest ones (р<0,05). Conclusions. Thereby, the studies found that tested acid resistance of enamel in patients with wedge-shaped defects is rather high. Study of marginal bonding of the EsthetX, Dentsply nanomicrohybrid material in restoration of teeth with wedge-shaped defects on the perimeter of restoration by the method of computer analysis of digital imaging and on micro permeability prove that application of dental adhesive with etching, made in advance, dur-ing 60 seconds provides with better results in comparison with etching during 30 seconds or self- etching dental adhesive application.
