The Restoration Of Different Prosthetic Materials In Subgingival Wedge-shaped Defect And Its Effects On Local Periodontal Tissues

Objective Wedge-shaped defect is an abrasion that caused by long-time abrasion in tooth cervical. It is well-known to be prevalent in oral noncarious disease.While wedge shaped defect is be close to or be lower to gingiva, the unfavorable influences could be serious. If the harmful effect of fillings was going on, it could bring about local gingivitis. And so, the healthy periodontium is a important standard that evaluating the restorative effect of wedge-shaped defects. In our test, We selected the teeth with wedge-shaped defects of approaching-gingiva or subgingiva and chose two restorative materials which are used in common newly were used filling defects.At the same time, we can evaluate the periodontal conditions when restored by different filling materials.Methods A total of 80 maxillary premolars with buccofacialy wedge-shaped defects at subgingival depth of 0~1mm were selected. These cervical defects were divided to approaching gingival groups and subgingival groups and cured randomly by the resin-modified glass ionomer(FujiⅡLC RMGI, Fuji, Japan) and the nanometer composite resin(Filtek TM Z350, 3M, USA). These teeth were divided to4 groups and every a group is 20 cases. According to position of defects and fillings,the cases were divided:( Ⅰ :RMGI + appaching-gingiva; Ⅱ :Z350 +appaching-gingiva;Ⅲ:RMGI+ subgingiva;Ⅳ:Z350+ subgingiva). The periodontal conditions were followed by pre-cured, 6 months, 12 months after restoring defects.Then we collected and weighed the volume of gingival crevicular fluid(GCF)samples of teeth. In additional, we analyzed aspartase aminotransferase(AST) 、alkaline phosphatase(ALP) and interleukin-1β(IL-1β) level of GCF in laboratory. All data in study were analyzed statistically by SPSS 17.0 and were utilized by paired t-test(pre-cured and 6 months; pre-cured and 12 months). All fillings were followed up, the clinical results were evaluated by USPHS standard.Results1 GCF volumeThe GCF volume was universally increasing after filled in all 4 groups. And GCF volume was gradually raising as time goes on. The GCF volume was gone up after 12 months more than it before teeth were cured. The data(Ⅲ group and Ⅳgroup)existed difference in statistics(P<0.05). In additional, GCF volume of subgingival teeth cured by two materials were increasing after 12 months, and GCF existed difference in statistics after operation(P <0.001).2 GCF-AST levelGCF-AST was universally increasing after 6 months in all 4 groups. In the Ⅱgroup(Z350 + appaching-gingiva), the GCF-AST was no significant difference.However, in the other three groups, the data were significant difference in statistics after 6 months(P<0.05). Especially inⅠgroup and Ⅲgroup it is observed that be filled by RMGI, the GCF-AST was analyzed statistically difference after 12months(P<0.001). Z350(Ⅱgroup 和Ⅳgroup)were difference in statistics(P<0.05).3 GCF-ALP levelIn 4 groups, GCF-ALP wasn’t varied significantly after 6 months and wasn’t different in statistics(P>0.05). During 12 months after filled, local periodontium was injured by fillings and plaque.In 4 groups they were difference in statistics(P <0.05).4 IL-1β level in GCFIn RMGI cases( Ⅰ group and Ⅲ group) the IL-1β was increasing significantly after 12 months, and was observed different significantly in statistics(P<0.001).Especially, the IL-1β in subgingival cases existed different in statistics(P<0.05) in 6months. Besides, the IL-1β level of Z350 after filled wasn’t varied apparently(P<0.05). However, the IL-1β added and existed difference in statistics(P <0.05).5 USPHS clinical evaluationIn RMGI groups most of USPHS index presented fine and didn’t occur recurrent caries and postoperative sensitivity during 6 months or 12 months after filled. After12 months individual teeth showed marginal discoloration、Color match and surface texture roughly,even those teeth could bring about slight crackles. It is because that RMGI mechanical strength were reducing apparently in long-term. At the same time,these fillings were carried by plaque obviously and were occurred marginal sealing.In groups of nanometer resin, most of USPHS index presented very good, such as color match harmonize, power strength, anti-wear, anatomical form normal. And these teeth weren’t occur recurrent caries and postoperative sensitivity. So thenanometer resin brought about more excellently in clinic than RMGI. Only a few teeth occurred marginal sealing badly. In additional, it is more common that the marginal sealing was presented badly in subgingival wedge-shaped defects teeth.It is because that looking and operation difficultly.6 Periodontal condition indexIn approaching-gingival cases, Z350 resins hardly injured periodontal tissues after or 12 months. The majority of PLI(plaque index) and PD(probing depth) could vary little than preoccrred and wasn’t different in statistics(P>0.05). In subgingival cases,the periodontal conditions were varied little than pre-filled after 6 months. With plaque accumulation, the index of SBI(sulcus bleeding index)、PLI and PD added and existed difference in statistics(P <0.05).In approaching-gingival cases of RMGI, the periodontal conditions present good in 6 months and PLI、PD and SBI were varied little and wasn’t different(P>0.05).After 12 months, PLI and PD added too much and existed difference in statistics(P<0.05). In subgingival cases, the PD index increasing obviously(P<0.05) in 6months.PLI, SBI,PD of teeth were added too much in 12 months(P<0.05).Conclusions1 Nanometer composite resin has good mechanival strength, anti-wear and colormatch. And USPHS index and clinical effect are superior to RMGI.2 The periodontal effect of wedge-shaped defect is related to the position of defectsby same materials. If it was deep into GCF, the periodontal conditions could bepoor and the effect of prosthetic materials on periodontal tissues could be curious.3 The level of IL-1β、ALP and AST in GCF could express degree of periodontaldisease, and these indexes may be used in studying periodontal effect afterrestored defects.