Application Of Three Kinds Of Flowable Resins In The Minimal Invasion Treatment Of Pit And Fissure Caries

Objective:The pit and fissure caries occur in enamel and/or dentin around pits and fissures on the surface of the teeth easily. Its treatment develops from early permanent filling by silver amalgam after the extensive prevention to preventive resin restoration now. With the rapid development of oral materials and the bonding technology, the new flowable filling materials had attracted extensive research from scholars at home and abroad. Due to the reduction of inorganic filler proportion, the new flowable filling materials has good permeability and mobility, enhanced adhesion between the resin and tooth tissue. It is considered one of the ideal filling materials in currently minimal intervention treatment for pit and fissure caries on permanent teeth.This study is consisted of two parts. Part one: The purpose of this part is to evaluate the clinical effect of constic、Beautifil Flow Plus F00 and 3M? ESPE? Filtek? Z350 XT in the treatment of pit and fissure caries and to record the resin filling operation time. Part two:The purpose is to provide theoretical supports for selecting suitable resins by observing their microleakage and gaps between fillings and teeth in vitro study.Methods: 1 Experiment One: A total of 120 permanent premolars or molars with pit and fissure caries in 41 patients(20 males,21 females) aged from 15 to 23 years, were collected from The Department of Oral Medicine, Dental Hospital of Hebei Medical University. Inclusive Criteria:pit and fissure caries which could stuck probes; deep pits and fissures where were the tendency of caries; early-stage caries in fissures, namely, enamel is nontransparent or chalk white; teeth without enamel hypoplasia, dental fluorosis, tetracycline pigmentation teeth, any other caries or fillings.The 120 teeth were divided into three groups on average and named Group A, B and C. Group A is filled by constic, group B is filled by Beautifil Flow Plus F00, group C is filled by 3M? ESPE? Filtek? Z350 XT.1.1 Diagnosing, processing and colorimetry: Firstly, rots was removed by slow speed half ball type drill and an slightly open shape was prepared by using tinny high speed silicon carbide burs, to guarantee the color in cavity as same as normal tooth tissue. Secondly, teeth surfaces and fissures were cleaned by a tiny conical-shape brush with a little of dentifrice. Lastly, the teeth were rinsed off and dried by distilled water. 1.2 Group A was filled with constic: Firstly, a layer of resin was smeared on walls and bottoms of cavity, less than 0.5mm. A dedicated brush scrub the resin for 25 seconds, then lighted for 20 s. Secondly, another layer of resin was smeared less than 2mm, then lighted for 20 s. Lastly, the remaining teeth were acid-etched for 30 s then rinsed for 15 s.Confirm that etching acid was removed completely. Prime & Bond NT bonder was brushed on surfaces of cavity after dried, wait for 20 s. Next, the bonder was lighted for 20 s. Group B was filled with Beautifil Flow Plus F00: Cavity was filled by directly compressive injection. Injected resin was less than 2mm each time, avoided bubbling before lighted for 20 s. Group C was filled with 3M? ESPE? Filtek? Z350 XT: The resin was directly injected into the cavity. Injected resin was less than 2mm each time and avoided bubbling before lighted for 40 s.Checked if there were eminences on occlusion surfaces. If there it is, involved occlusion surfaces should be modified. Then polished by slow speed rubber wheel dipped in toothpaste. Record every filling time. 1.3 All prostheses were reviewed after one, three and six months, regularly. 2 Experiment Two: The 60 extracted premolars and molars without lesion, enamel hypoplasia, dental fluorosis or tetracycline pigmentation teeth were collected from The Department of Oral & Maxillofacial Surgery, Dental Hospital of Hebei Medical University, and preserved in 4℃normal saline after cleaning. All teeth were divided into Group A, B and C, 20 teeth in each group. Group A is filled by constic, group B is filled by Beautifil Flow Plus F00, group C is filled by 3M? ESPE? Filtek? Z350 XT. 2.1 The cavity was produced along the teeth fissure by using high speed silicon carbide burs and slow speed half ball type drill, the depth is about 1.5 to 2mm. Group A, B and C were filled with Constic, Beautifil Flow Plus F00 and Filtek? Z350 XT respectively. 2.2 Preparate artificial saliva, all filled extracted teeth were immersed in artificial saliva at 37℃ as constant temperature for 30 day. 2.3 Thennocycling test: the teeth stayed in cold water(5℃) for 30 s, warm water(55℃) for 30 s in a cycle and repeated 500 times.2.4 10 teeth were pick out from each group for microleakage test and the remaining teeth were measured gaps between fillings and teeth tissue by SEM. 2.5 Recorded and graded microleakage on each tooth and gaps at the edge of the 0.2mm from the hole between fillings and teeth then analyzed statistically.Result:1 Each group of filling time accord with the Normal Distribution. Via Chi square test there are statistical differences among the groups(P<0.05), group A is the shortest, group B is shorter, group C was short.2 There were no difference in the effect of three kinds of resin, involving in prosthesis breakage, marginal seal, marginal discoloration, color coordination and secondary caries after one month, two months and three months(P>0.05), referring to Chen Dong’s criterion.3 The grades of 3 groups gained by using stereomicroscope were significantly different by Wilcoxon Mann-Whitney test. There were less microleakage in group B and group C compared with group A(P<0.05). No difference was observed between group B and group C(P>0.05).4 By SEM scanning from the tooth surface 0.2mm, lager gaps were observed in group A compared with group B and group C. There is significant difference(P<0.05). Smaller gaps were observed in group B compared and group C. There is no significant difference(P>0.05).Conclusion:1 Operating time: group constic cost less time than group Beautifil Flow Plus F00 and group Filtek? Z350 XT. Therefore, constic is more efficient than the others.2 The three resins can get good clinical reparative effects in pit and fissure caries treatment. There is no significant difference.3 Underwented stereomicroscope there were less microleakage in group Beautifil Flow Plus F00 and group Filtek? Z350 XT compared than group constic.4 By using SEM, lager gaps were observed in group constic compared with others. The marginal seal property of group Beautifil Flow Plus F00 and group Filtek? Z350 XT was better. We advise using constic dedicated brush should contact teeth adequately and cost more time in the step.