Consistency of gingival thickness measurement based on cone-beam CT imaging and cone-beam CT superimposed intraoral scan imaging / 中国组织工程研究

ABSTRACT

BACKGROUND:Gingival thickness is an important indicator to determine gingival phenotype.The correct evaluation of gingival phenotype is helpful for the smooth going of periodontal surgery,implant implantation and orthodontic treatment.The search for a comfortable,accurate and convenient method of measuring gingival thickness has always been a research hotspot in this field. OBJECTIVE:To analyze the gingival thickness in different dental positions and to study the consistency of cone-beam computed tomography(CBCT)image and digital intraoral scanners and cone-beam computed tomography(DIS-CBCT)superimposition image for measuring gingival thickness and determining whether the gingiva is thick or thin. METHODS:Twenty volunteers(10 males and 10 females)with complete maxillary dentition were recruited.The thickness of the gingiva 2 mm below the buccal gingival margin of 160 teeth was measured by CBCT image and DIS-CBCT digital superimposition image.Gingival thickness was used to determine whether the gingiva was thick or thin.Paired t-test was used to analyze the differences in gingival thickness measured by the two methods.Pearson correlation analysis was used to evaluate the correlation between the gingival thickness results of the two methods.The intraclass correlation coefficient(ICC)and Bland-AItman chart were used to analyze the repeatability and consistency in measuring gingival thickness using the two methods.Kappa value was used to analyze the consistency in determining whether the gingiva was thick or thin using the two methods. RESULTS AND CONCLUSION:The gingival thickness measured by CBCT image and DIS-CBCT digital superimposition image was(1.47±0.39)and(1.42±0.36)mm,respectively(t=5.673,P＜0.05).Pearson correlation analysis showed that the gingival thickness measured by the two methods was positively correlated(r=0.968,P＜0.001).In the CBCT group,the values of intraobserver and interobserver ICC were 0.980-0.982 and 0.984,respectively;in the DIS-CBCT group,the values of intraobserver and interobserver ICC were 0.941-0.984 and 0.964,respectively(P＜0.001).The intergroup ICC value of gingival thickness measured by the two methods was 0.967(P＜0.001).Bland-AItman analysis showed that 4.37%(7/160)of the points measured by both methods for gingival thickness was outside the 95%limits of agreement.There were 71 cases of thick-gingiva and 89 cases of thin-gingiva measured by CBCT imaging,and 59 cases of thick-gingiva and 101 cases of thin-gingiva measured by DIS-CBCT digital superimposition image.The Kappa value of the two groups was 0.845(P＜0.001).These findings indicate that there is a significant difference in the thickness measurement of the gingiva 2 mm below the gingival margin between the CBCT group and the DIS-CBCT group,but the correlation is very strong.The repeatability and consistency of gingival thickness measurement are both high,and there is a good consistency between the two methods when used to determine whether the gingiva is thick or thin.