DDS, PhD, Lithuanian University of Health Sciences, Medical Academy, Department of Orthodontics, Kaunas, Lithuania.
DDS, Lithuanian University of Health Sciences, Medical Academy, Department of Orthodontics, Kaunas, Lithuania.
Sci Rep. 2019 Apr 11;9(1):5957. doi: 10.1038/s41598-019-42325-4.
The objective of this in vitro study was to determine the effects of dental fluorosis on the tensile bond strength of metal brackets bonded to human teeth and to evaluate the changes in the tooth enamel surface after debonding. The study sample consisted of 68 recently extracted human upper premolars, which were divided into 2 groups: the fluorosis group (34 fluorosed teeth) and the control group (34 healthy teeth). Identical premolar metal brackets were bonded on the buccal surfaces of the teeth. Both groups were submitted to a tension test using a universal testing machine. The number and length of the enamel microcracks in the buccal surface of each tooth were determined before bracket bonding and after debonding using a stereomicroscope. The percentage adhesive remnant index (PARI) was calculated after debonding. The results showed that the tensile bond strength (TBS) of brackets bonded to fluorosed teeth was 21.08% lower than that of brackets bonded to healthy teeth (p < 0.0001). The length of the enamel microcracks on fluorosed teeth increased by 47.4% after debonding, whereas the control group showed an increase of only 12.6%. The PARI showed lower values for fluorosed teeth in comparison to the control group (p = 0.047). In conclusion, dental fluorosis has a negative impact on tensile bond strength and the length of microcracks formed after bracket debonding.
本体外研究旨在确定氟斑牙对人牙金属托槽粘结拉伸粘结强度的影响，并评估脱落后牙釉质表面的变化。研究样本包括 68 颗最近从上颌前磨牙中提取的牙齿，分为两组：氟斑牙组（34 颗氟斑牙）和对照组（34 颗健康牙）。在牙齿的颊面粘结相同的前磨牙金属托槽。两组均使用万能试验机进行拉伸试验。使用立体显微镜在粘结前和脱落后确定每个牙齿颊面釉质微裂纹的数量和长度。脱落后计算粘结残留指数（PARI）。结果表明，粘结到氟斑牙上的托槽的拉伸粘结强度（TBS）比粘结到健康牙上的托槽低 21.08%（p<0.0001）。脱落后氟斑牙上釉质微裂纹的长度增加了 47.4%，而对照组仅增加了 12.6%。与对照组相比，氟斑牙的 PARI 值较低（p=0.047）。总之，氟斑牙对托槽脱落后形成的拉伸粘结强度和微裂纹长度有负面影响。
