Objective

To evaluate the adhesion of Streptococcus mutans to preformed zirconia and stainless steel crowns and compare plaque accumulation and gingival inflammation over a period of 1 year.

Materials and methods

Thirty children between 6 to 9 years with pulpectomised bilateral mandibular primary second molars were randomly divided into zirconia/stainless steel groups. Plaque was collected from the crowns using swabs at 3, 6, 9, and 12 months. Gingival and plaque index were recorded at all follow-ups. S. mutans was cultured on tryptone-yeast-cysteine-sucrose-bacitracin agar, and organisms were expressed as colony-forming units. Within-group analysis was performed using repeated measures ANOVA and between-groups using the independent T test.

Results

S. mutans were found in significantly higher numbers on the stainless steel crowns as compared with zirconia crowns at all the follow-ups. Gingival inflammation and plaque index scores were also significantly higher around the stainless steel crowns as compared with zirconia at the end of 12 months follow-up.

Conclusion

Adhesion of S. mutans to stainless steel crowns was significantly greater when compared with zirconia, and minimal gingival inflammation and plaque accumulation was found in the tooth restored with zirconia crowns as compared with stainless steel crowns.

Clinical relevance

Preformed zirconia crowns prevents adhesion of S. mutans onto its surface, and reduces plaque accumulation around the crown, inflammation of surrounding gingiva compared to conventional stainless-steel crowns. Pediatric zirconia crowns could help in reducing the overall microbial density and prevalence in the oral cavity, thus reducing the caries risk in the long term.

中文翻译：

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评估变形链球菌的粘附力，氧化锆和不锈钢冠上的斑块堆积以及原发磨牙的周围牙龈发炎：随机对照试验。

目的

为了评估变形链球菌对预先形成的氧化锆和不锈钢牙冠的粘附力，并比较牙菌斑积聚和牙龈炎症在1年的时间。

材料和方法

年龄在6至9岁之间的30名儿童，其双侧下颌切牙切除术被随机分为氧化锆/不锈钢组。在3、6、9和12个月时，用棉签从牙冠上收集牙菌斑。在所有随访中均记录了牙龈和牙菌斑指数。在胰蛋白-酵母-半胱氨酸-蔗糖-杆菌素琼脂上培养变形链球菌，并将生物体表示为菌落形成单位。使用重复测量方差分析进行组内分析，使用独立的T检验进行组间分析。

结果

在所有后续随访中，发现不锈钢冠上的变形链球菌均明显高于氧化锆冠。在术后12个月末，与氧化锆相比，不锈钢冠周围的牙龈炎症和菌斑指数得分也明显更高。

结论

与氧化锆相比，变形链球菌对不锈钢牙冠的粘附力明显更高，与不锈钢牙冠相比，氧化锆牙冠修复的牙齿中牙龈发炎和牙菌斑积聚最小。

临床相关性

与传统的不锈钢牙冠相比，预制的氧化锆牙冠可防止变形链球菌粘附在其表面上，并减少牙冠周围的斑块积聚和周围牙龈的炎症。小儿氧化锆冠可以帮助降低口腔中的总体微生物密度和患病率，从而从长远来看降低龋齿风险。