Prevalence And Risk Factors Of Interproximal Contact Loss Between Implant-supported Prostheses And Adjacent Teeth

ObjectiveICL,which was first defined in 2008 by Wei et al.,means the interproximal contact loss between implant-supported prostheses and its adjacent natural tooth.ICL may cause food impaction,peri-implantitis(PI)and caries in adjacent teeth.It is widely understood that ICL is caused by tooth migration,occlusion,crown related factors and retention type.However,it is still lack of sufficient evidence to draw a definite conclusion regarding the factors associated with ICL.To further explore the prevalence and risk factors for ICL after implant restoration,we conducted this study by collecting and examining the records of patients who had been treated implant-supported prostheses at the SATH Stomatological Hospital over the past decade.MethodsAccording to the criteria of inclusion and exclusion.Participants who had been treated with implant-supported prostheses between January 2011 and December 2020 were included in this study.We reviewed the medical record of participants.Participants independently completed a questionnaire before clinical examination.ICL was measured using aluminum strips.In the same time,periodontal condition,occlusion,and additional factors were examined.Data analysis was performed with SPSS 24.0 software(New York,NY,USA).The prevalence of ICL was calculated at three levels(patient,mesial and distal).For each implant-supported prostheses,the ICL at the mesial and the distal sides were examined separately.Chi-square tests and U tests were used to analyze any factors associated with ICL.The level of significance was set at 0.05.Furthermore,Logistic regression analysis was used to investigate independent factors influencing ICL and multiple linear regression analysis was performed to investigate the association between independent factors and interspace thickness.Results(1)The prevalence of ICL grew with the function time.A total of 204 participants were enrolled in the study,including 93 females and 111 males.Among all the examined participants,122(59.8%)had more than one site judged as mesial or distal ICL.Of the 565 contact sites between implant-supported prostheses,138(40%)were judged as ICL at mesial sites,while 53(24.1%)were judged as ICL at distal sites.The prevalence of ICL in the mesial site was significantly higher than that in the distal site(p<0.05).(2)Chi-square tests was used to analyze associate factors of ICL at the participant level.The results showed that age,gender,diabetes history,smoking history,regular periodontal scaling,bruxism and unilateral chew were not significantly associated with ICL.But the participants who were unilateral mastication or not regular periodontal scaling would have more opportunity to occur ICL.(3)Chi-square tests and U tests were used to analyze any factors between ICL at the mesial site.The results showed that food impaction,implant location,connection type,status of adjacent teeth,endodontic conditions and function time were significantly associated with ICL at the mesial side.There were no significant differences among the following factors: implant site,prostheses retained and bone loss.Logistic regression was used to reveal the independent factors of ICL as multivariate analysis methods.Food impaction and status of adjacent teeth were risk factors for ICL at the mesial site.There was a strong correlation between food impaction(OR=3.084,P=0.000)and ICL.Status of adjacent teeth was significantly associated with ICL;moreover,crown(OR=1.516,P=0.238)had a higher risk than natural tooth and implant(OR=0.308,P=0.005).In the multiple regression model,interspace thickness was associated with food impaction(B=17.152,P=0.041),function time(B =6.870,P=0.000),status of adjacent teeth(implant/implant)(B=-34.241,P=0.000),retraction of gingival papilla(B=26.532,P=0.001)and connection type(B=34.927,P=0.003).(4)Chi-square tests and U tests were used to analyze any factors associated with ICL at the distal site.The results showed that food impaction,mechanical complications,occlusion,opposite-tooth wear,full-mouth wear and retraction of gingival papilla were significantly associated with ICL at the distal side.There were no significant differences among the following factors: restoration material,probing for depth,and probing for bleeding.Logistic regression was used to reveal the independent factors of ICL as multivariate analysis methods.Mechanical complications,occlusion and PI were risk factors for ICL in the distal site.There was a strong correlation between mechanical complications(OR=10.657,P=0.000)and ICL.Occlusion(OR=3.610,P=0.012)was significantly associated with ICL;moreover,group function had a higher risk than canine guidance.In addition,PI(OR=3.634,P=0.024)was positively correlated with ICL.In the multiple regression model,interspace thickness was associated with mechanical complications(B=39.434,P=0.006),retraction of gingival papilla(B=38.150,P=0.000).Conclusion(1)In conclusion,the prevalence of ICL at the participant level was 59.8%.The prevalence of ICL at the proximal contact site level was 40% at the mesial and 24.1% at the distal.(2)Food impaction,implant location,connection type,status of adjacent teeth,endodontic conditions and function time were significantly associated with ICL at the mesial side.Food impaction,function time and status of adjacent teeth were independent factors for ICL.Interspace thickness was associated with food impaction,function time,status of adjacent teeth(implant/implant),retraction of gingival papilla and connection type.(3)Food impaction,mechanical complications,occlusion,opposite-tooth wear,full-mouth wear and retraction of gingival papilla were significantly associated with ICL at the distal side.Mechanical complications,occlusion and PI were risk factors for ICL in the distal site.Interspace thickness was associated with mechanical complications and retraction of gingival papilla.