Study On The Relationship Between Bone Cortex Thickness And Dental Implant Accuracy Based On Linear Measurement Of Cone-Beam CT

PurposeIn stomatology,the continuous development of dental implant technology is obvious to all.Meanwhile,Cone-Beam Computed Tomography（CBCT）has been widely used in dental implant for preoperative evaluation.Based on "fixing oriented" concept,clinical doctors are chasing for the higher precision of the dental implants,thus establish an effective bridge between CBCT and dental implant accuracy,implementation of preoperative CBCT on the area,effective measurements to a preliminary assessment of bone parameter prediction precision dental implants,will provide great convenience for clinical work.In this study,we compared the cortical bone thickness（CBT）of the alveolar ridge in the missing tooth region between CBCT images and pathological sections to explore the feasibility of CBCT in evaluating CBT in the posterior tooth region of the jaw.Then,based on linear measurement of CBCT,the effect of CBT on implant accuracy in mandibular posterior region was studied.MethodsThis study included two experiments.In experiment one,60 patients with posterior tooth loss admitted to stomatology center of our hospital from June to December 2019 were selected,23 males and 37 females are included,at an average age of（43.8±1.7）years old.A total of 63 bone fragments were removed from the area of tooth-missing.Preoperative cone-beam CT images of patients were imported into the oral implant navigation system,and CBT（cone-beam CT image group）of alveolar crest in the proposed planting area was measured on the measurement interface after the design was completed.During the operation,the target bone block was sectioning with a thickness of 0.4μm,and CBT（pathological image group）in the sectioning was measured by Case Viewer software.In experiment two,totally 30patients（6 males and 24 females,at an average age of（43.1±14.1）years old）with 37 implants in the mandibular posterior dental implant area who visited the stomatology center of our hospital from June to December 2020 were included.CBT was measured in the buccal and lingual sides of implants’ neck and the mean value was calculated.The mean value was separated into two groups（Group A was CBT ≥1.5mm;Group B was CBT < 1.5mm）,and the differences between the vertex,apex and angle of implant were analyzed.SPSS 26.0 software was used for data analysis,normality test and analysis of variance were performed.In this study,independent sample T test was used to compare the accuracy of implantation vertex between two groups of different CBT,and rank sum test was used to compare the accuracy of implantation terminal point and implantation angle between two groups of different CBT.P < 0.05 was considered statistically significant.ResultsExperiment 1: The thickness of bone cortex in the posterior teeth,maxillary posterior teeth and mandibular posterior teeth were（1.20±0.75）mm,（0.68± 0.46）mm and（1.48±0.77）mm,respectively,in the pathological image group.Values were（1.14±0.77）mm,（0.64±0.24）mm and（1.41±0.83）mm,respectively,in the cone-beam CT group.There was no statistical significance between the statistics of the two groups in the same position（P>0.05）.Experiment 2: CBT ≥ 1.5mm group and CBT < 1.5mm group had significant differences in implant vertex,terminal point and angle deviation（P < 0.05）,and CBT≥ 1.5mm group had small deviation.ConclusionCBCT can be used for linear measurement analysis of CBT with high accuracy.In clinical practice,when dynamic navigation is used to guide dental implantation,the local bone status of patients should be fully considered before surgery and sufficient safe distance should be maintained,which is more conducive to progressing the success rate of precision dental implantation.