Objective: To evaluate the feasibility of full-mouth debridement ( subgingival scaling and root planning , SRP) by 2 times within 1 week and compare the clinical effects of different sequences of debridement-antibiotic usage in patients with severe chronic periodontitis ( CP ) .Methods: A double-blinded, placebo-controlled, randomized clinical trial was conducted in 30 severe CP patients (14 males and 16 females, 40.5 ±8.4 years old on average from 35 to 60 ) receiving 3 different sequences of debridement-antibiotictherapy:Group A, antibiotic usage (metronidazole, MTZ, 0.2 g, tid, 7 d;amo-xicillin, AMX 0.5 g, tid, 7 d) was started together with SRP ( completed by 2 times in 7 d);Group B, antibiotic usage (MTZ 0.2 g, tid, 7 d;AMX 0.5 g, tid, 7 d) was started 1 d after SRP(completed by 2 times in 7 d);Group C, SRP alone[probing depth (PD), bleeding index (BI) and tooth mobility] was examined .The average full-mouth probing depth , the average full-mouth proximal probing depth ( pPD) , the percentage of sites with PD >5 mm ( PD>5 mm%) , the percentage of sites with proximal PD>5 mm ( pPD>5 mm%) , the average bleeding index ( BI) and the percentage of sites with bleeding on probing ( BOP%) were calculated .Clinical examinations were performed at baseline and 2 months post therapy .Results:(1) Compared with baseline conditions , all the subjects showed clinical improve-ments in all the parameters evaluated 2 months post therapy , P<0 .05 .( 2 ) Significant difference were observed in the average PD changes between Group A [(2.15 ±0.42) mm], Group B [(1.76 ±0.29) mm] and Group C [(1.57 ±0.33) mm], P<0.05.No significant difference was observed in the aver-age PD changes between Group B and Group C , P=0.354.Significant differences were observed in the average pPD changes between Group A [(2.45 ±0.43)mm] and Group C[(1.90 ±0.48) mm], P<0.05.No significant difference was observed in BI and BOP% changes between Group A ,Group B and Group C.Conclusion: For patients with severe chronic periodontitis , it is safe and feasible to receive full-mouth SRP by 2 times within 1 week.The short-term ( 2 months ) advantages in PD changes are observed in patients receiving SRP and antibiotic usage at the same time comparing with patients using antibiotics after SRP or SRP alone .

Objective:To investigate the potential association between FADS1 rs1 74537 polymorphism and serum proteins in patients with aggressive periodontitis,which may provide benefits for diagnosis and treatment of aggressive periodontitis.Methods:A total of 353 patients with aggressive periodontitis (group AgP)and 1 25 matched controls (group HP)were recruited in the study.Genotyping of FADS1 rs1 74537 and serum biochemical indexes were tested at the study’s start.The relationships between the levels of TP,GLB,ALB,A/G and genotyping were analyzed.Results:(1 )The detection rate of allele G in group AgP was higher than that in group HP(68.1% vs.61 .2%,P=0.046,OR=1 .35,95% CI 1 .00-1 .83 );the detection rate of genotype GG in group AgP was higher than in group HP(45 .5%vs. 34.4%,P=0.029,OR=1 .60,95%CI 1 .05 -2.44).(2)In group AgP,the patients with GG geno-type exhibited significantly lower TP,GLB than the patients with GT+TT genotype [(77.08 ±7.88)g/L vs.(79.00 ±4.66)g/L,P=0.007;(28.1 7 ±7.63)g/L vs.(29.88 ±3.49)g/L,P=0.007)and the higher A/G(1 .72 ±0.22 vs.1 .67 ±0.22,P=0.040),but there was no significant difference in ALB between the patients with GG genotype and the patients with GT+TT genotype.In group HP,there were no significant differences in TP,GLB,A/G and ALB between individuals with genotype GT+TT and with genotype GG.(3 )Compared with individuals with genotype GT+TT in group HP,the AgP pa-tients with genotype GT +TT exhibited significantly higher TP,GLB [(79.00 ±4.66 ) g/L vs. (75.20 ±4.53)g/L,P<0.01;(29.88 ±3.49)g/L vs.(26.55 ±2.94)g/L,P<0.01 )and the lo-wer A/G(1 .67 ±0.22 vs.1 .88 ±0.30,P<0.01 ),but there was no significant difference in ALB. There were no significant differences in TP,GLB,A/G and ALB the between the AgP patients with ge-notype GG and the healthy subjects with the same genotype either.Conclusion:FADS1 rs1 74537 poly-morphism is associated with aggressive periodontitis.The patients with genotype GG in group AgP had relatively lower TP,GLB and higher A/G.Genotype GG might be a risk indicator for aggressive periodon-titis by reducing host defense capability and contributing to inflammatory response in the occurrence and development of aggressive periodontitis.