Digital Analysis Of The Correlation Between Root Piece Length And Jumping Gap Around Socket Shield Technique In The Aesthetic Zone

Objective:In this research,the distance between the root tips of the root fragments and the implants was measured in the medio-sagittal view of each tooth position in the aesthetic zone by applying the digital method to virtual the socket shield technology,with the purpose of investigating the effect of tooth positions and root fragment lengths on the jumping gap in the aesthetic zone.The purpose of this study was to provide a guideline for the prognosis assessment and to prevent complications of the socket shield technology in the aesthetic zone.Methods:Based on the inclusion and exclusion criteria,200 cone beam computerized tomography(CBCT)images were retrospectively collected from January 2020 to September 2021 at the Shanxi Medical University School and Hospital of Stomatology,of which 70 were male and 130 were female,aged 39.9±11.1 years old.CBCT was obtained from Asians aged 18 years or older who met the following inclusion criteria:CBCT images of the aesthetic region were complete with normal tooth morphology and position;CBCT images included both the upper and lower jaws;CBCT images of the aesthetic region were free of distortion;the anterior region had normal occlusion and healthy dentition and periodontium;the root relationship was Kan Classification I;CBCT images were obtained using the same equipment and parameters.All data collected in this study were obtained using the same cone beam CT machine(Ka Vo 3D e Xam,Germany)and by the same photographer.The acquired CBCT data were imported in DICOM file format into SIMPLANT Pro Lab 17.01 software(Materialise Clinical Service Inc.,Leuven,Belgium)and the implants were placed in the desired 3D position in a restorative and biologically oriented virtual manner.After selecting the tooth to be measured in the panoramic view,the distance from the root tips of the root fragments to the implants at 4 mm,6 mm and 8 mm below the top of the alveolar crest on the labial side of the central incisors,lateral incisors and cuspids was measured and recorded at 400 times magnification.All measurements were taken by a highly trained postgraduate student at the School of Stomatology,Shanxi Medical University,and repeated by the same postgraduate student after an interval of 2 weeks,with the mean value taken as the final study data for analysis.Results:In this study,a total of 200 CBCT images were collected based on inclusion criteria as well as exclusion criteria,including 70 males and 130 females,aged 39.9±11.1 years old.The distance from the root tips of the root fragments to the implants at 4 mm,6mm and 8 mm below the top of the labial alveolar ridge after socket shield technology of the central incisors,lateral incisors and cuspids was measured by image reconstruction analysis using SIMPLANT Pro Lab 17.01 software(Materialise Clinical Service Inc.,Leuven,Belgium).The results are shown as follows.1.The differences between the various measurement locations for the jumping gap after socket shield technology for maxillary central incisors and cuspids were not statistically significant(P > 0.05),while the differences between the various measurement locations for the jumping gap after socket shield technology for maxillary lateral incisors were statistically significant(P < 0.05).A two-by-two comparison showed that the jumping gap was significantly smaller when the 8 mm root fragment was preserved than when 4 mm was preserved(P < 0.05).2.The difference in jump gaps between maxillary central and lateral incisors compared to cuspids was statistically significant(P < 0.05).A two-by-two comparison showed that maxillary cuspids had significantly greater jump gaps than maxillary central and lateral incisors at any measurement site(P < 0.05),while the difference in jump gaps between maxillary central and lateral incisors was not statistically significant(P > 0.05).3.There was no statistically significant difference between the genders of the maxillary anterior teeth with different root piece lengths preserved by socket shield technology for jumping gaps(P > 0.05).4.There was no statistically significant difference between the genders of the mandibular anterior teeth with different root piece lengths preserved by\ socket shield technology for jumping gaps(P > 0.05).5.The difference in jump gaps between the various measurement locations after socket shield technology for mandibular central incisors was not statistically significant,while the difference in jump gaps between the various measurement locations after socket shield technology for mandibular lateral incisors and cuspids was statistically significant(P < 0.05).A two-by-two comparison showed that the jumping gap was significantly smaller for mandibular lateral incisors with 6mm and 8mm preserved root fragments than for 4mm retained(P < 0.05)and for mandibular cuspids with 8mm preserved root fragments than for 4mm and 6mm retained(P < 0.05).6.There was no statistically significant difference between the genders of the mandibular anterior teeth with different root piece lengths preserved by socket shield technology for jumping gaps(P > 0.05).Conclusion:1.When performing socket shield technology in the maxillary anterior region,the central incisors and cuspids can be preserved in 4mm,6mm and 8mm lengths of root fragments,respectively.In contrast,when an 8 mm length of root fragment is preserved in the lateral incisor,there is a greater risk of contact between the root fragment and the implant.All maxillary cuspids have greater jumping gaps than the central and lateral incisors when socket shield technology is performed.2.When performing socket shield technology in the mandibular anterior region,there is a risk of insufficient space for implant placement in case of preserved 6 mm and 8mm root fragments in the central incisors.The possibility of contact between the implant and the root fragment is greater when the 6mm root fragment is preserved in the lateral incisor,and preserving the 8mm root fragment would interfere with implant placement.The jump gap is significantly reduced when the cuspids are preserved with an 8 mm length of root piece,but a jump gap of 1.0.-1.5 mm is still present.The jumping gap in the mandibular cuspids is greater than in both the central and lateral incisors when the socket shield technology is performed.3.Gender has no effect on jumping gaps when socket shield technology is performed in both the maxillary and mandibular anterior region.