Clinical Effect Of Different Gingival Biotypes On Surgical Crown Lengthening

Objective:(1)The relationship between gingival thickness,keratinized gingival width,periodontal probing depth and biologic width were investigated by clinical examination or indirect measurement,and the relationship between gingival thickness and gingival biotype was studied.(2)The effects of gingival biotype on the stability of gingival margin were studied by observing the position of gingival margin after crown lengthening.Methods:This study selected 11 patients(2 men,9 women)a total of 56 teeth,all of which were maxillary anterior teeth,were preoperatively treated with periodontal basic treatment.The gingival thickness(GT)was measured by puncture measurement before operation,and the average probing depth(PD)and the keratinized gingival width(KGW)were recorded.The distance between the crest of the alveolar ridge and cemento-enamel junction(CEJ)was measured in the process of surgery,and the biological width(BW)was recorded.The position of gingival margin was recorded at 1 week,1 month,2months and 3 months postoperatively.The thin gingival biotype was group A,and the thick gingival biotype was group B.The data were analyzed by Spss21.0,and the independent sample t test was used to test the difference hypothesis.The change of gingival margin was using the nonparametric test,.The statistics show that p<0.05 is asignificant difference.Results:The average detection depth(PD): group A(2.29 + 0.35)mm,B group(2.49 + 0.45)mm,P = 0.061 > 0.05,the difference was not statistically significant.Keratinized gingival width(KGW): group A(5.60 + 2.74)mm,group B(7.92 + 3.07)mm,group A < B,P =0.004** < 0.01,the difference was statistically significant.Biological width(BW): group A(2.12 + 0.58)mm,group B(2.62 + 0.86)mm,group A < B,P = 0.017* < 0.05,the difference was statistically significant.Within 1 weeks to 1 months,the change of gingival margin was A group-0.95 +1.00 mm,B group-0.90 + 1.10 mm,p=0.639>0.05,the difference was not statistically significant.Within 1 months to 2 months,the marginal changes of gingival margin were0.10 + 0.50 mm in group A and 0.30 + 0.90 mm in group B,and the difference was not statistically significant?Within 2 months to 3 months,the marginal change of gingival margin was 0.40 + 0.30 mm in group A,and 0.95 + 0.90 mm in group B,p=0.006<0.05,the difference was statistically significant.Conclusion:The thicker gingival biotype has wider keratinized gingival width(KGW)and wider biological width(BW)than the thin gingival biotype.There is no significant difference in the periodontal probing depth(PD)between the two gingival biotypes.In the 1 months after the crown lengthening,gingival recession will occur in the two gingival biotypes,and there is no significant difference between them;After 2 months of crown lengthening surgery,two gingival biotype's gingival margin tended to grow towards the crown.Thick biotype increased more than the thin biological type,suggesting that thick gingival biotype needs longer postoperative recovery time than thin gingival biotype.