Study On The Related Factors Of Buccal Bone Plate Fracture In The Application Of Ridge-split

Objective:At present,the ridge-split technique is often used to solve the problem of insufficient horizontal bone volume in the implant area,and its curative effect has been confirmed by the literature.However,there is a risk of fracturing the buccal lamella in the augmentation region during the the application of this technique,it will effect the buccal bone level around the implant,which concerns its long-term stability and aesthetic problems,however the risk factors of buccal plate fracture in the process of ridge-split are not clear till now.In this study,an experimental model of ridge-split was established with porcine ribs to analyze the related factors of buccal plate fracture in the operation of ridge-split,to provide references for clinical decision-making.Materials and methods: The conditions of the selected bone segment are as follows:the width of the bone crest is about 4mm,and the vertical height is not less than 15 mm,which is chosen as the experimental model.The bone splitting was performed with the Dentium RS Kit.The length of the horizontal osteotomy line of the crest was 7mm and the vertical osteotomy lines were 6mm.A Dentium implant with a diameter of 4.0mm and a length of 10 mm was inserted.According to the condition of the buccal bone plate after the implantation of the implant,the experimental models were divided into fracture group and non-fracture group.The variables that may be related to buccal plate fracture were measured,and the data were recorded and calculated.The datas can be directly measured include:the thickness of the buccal bone plate at the crest(pre-implantation),the thickness of the buccal bone plate at the crest(post-implantation),the thickness of the lingual bone plate at the crest(pre-implantation),the thickness of the lingual bone plate at the crest(post-implantation),the thickness of bone plate at the midpoint of the buccal side,the thickness of cortical bone at the midpoint of the buccal side,the thickness of bone plate at the buccal base,the thickness of cortical bone at the buccal base,the buccal plate offset angle,the implant deviationangle;The relevant factors to be calculated include: the compression thickness of the buccal bone plate at the crest,the compression thickness of the lingual bone plate at the crest,the total compression thickness of buccal and lingual bone plates,the thickness of cancellous bone at the midpoint of buccal side,the ratio of the buccal cancellous bone to the cortical bone thickness(CC ratio),the thickness of cancellous bone at the buccal base,the horizontal displacement distance of the buccal bone plate.SPSS23.0 statistical software and suitable statistical methods were used for statistical analysis.Results: A total of 55 implants were inserted,of which 20 cases had buccal plate fractures and 35 cases had no fractures,accounting for 36% and 64% of the total,respectively.The ratio of the buccal cancellous bone to the cortical bone thickness,the horizontal displacement distance of buccal bone plate,the buccal plate offset angle and the thickness of cancellous bone at the buccal base between the two groups were statistically significant(P <0.05).The results of correlation analysis showed that the horizontal displacement of the buccal plate was the risk factor of buccal plate fracture.When the horizontal displacement of buccal plate was more than 3.5mm,the risk of buccal plate fracture would be increased by 13.57 times.In addition,the deviation angle of implant was positively correlated with the displacement angle of buccal bone plate.Further analysis shows that the thickness of cancellous bone at the midpoint of the buccal side and the ratio of the buccal cancellous bone to the cortical bone thickness(CC ratio)were negatively correlated with the buccal plate offset angle.The horizontal displacement of buccal bone plate was positively correlated with the buccal plate offset angle.The greater the thickness and proportion of cancellous bone of the buccal bone plate,the lower the buccal offset of buccal bone plate,the corresponding degree of implant deviation showed a small trend.Conclusion: There is a limit to the capacity of bone augmentation through ridge-split technique,and controlling the bone augmentation within a safe range will reduce the risk of buccal plate fracture.If the planned augmentation width exceeds the safe range,preventive measures and countermeasures can be taken in time.Besides,the displacement angle of buccal bone plate reflects the deviation of implant,and the offset angle of buccal bone plate after bone split is negatively correlated with the value representing the thickness and content of cancellous bone,It is known that the higher the cancellous bone content,the smaller the buccal offset of buccal bone plate after bone splitting,which is meaningful for the later denture restoration design.