Feasibility Study On Immediate Implantations Of The Maxillary First Molar By Using CBCT

[Objective]: In this study,the image data is obtained through the maxillary oral cone-beam CT(CBCT)measurement and three-dimensional reconstruction,and the distance between the maxillary first molars and the surrounding anatomic structures and alveolar bone is measured.By analyzing the three-dimensional measurements of the maxillary first molar CBCT images,and comparing the bone mass that the initial stability of the maxillary dental implantation is needed;this study could provide anatomical basis for the maxillary first molar implant promotion,and provide a reference for clinical maxillary first molar immediate implants,and the feasibility of maxillary first molar immediate implantations was analyzed.[Method]: From the CBCT images taken at Hefei Dental Hospital between January 2013 to January 2015,200 cases are randomly selected and analyzed in this work.In these cases,there are 102 males and 98 females,aged 25 ~ 45(31.6 ± 5.6)years,a total of 400 cases of maxillary first molar and the area around image data.The image data of these cases are measured and analyzed in CBCT system software.The distance of alveolar ridge to the floor of maxillary sinus,the distance of the molar root bifurcation to the floor of maxillary sinus,the distance of palatal root tip to the floor of maxillary sinus,and the distance of the molar root bifurcation to the surface of the alveolar bone buccal and palatal side,root interval width of root neck、root middle、root tip area are measured.All measurements are performed by a same dentist,and each measurement was repeated 3 times and the data averaged.[Results]: The average distance of alveolar ridge to the floor of maxillary sinus is(12.80 ± 2.59)mm for male and(11.29 ± 2.18)mm for female;the average distance of the molar root bifurcation to the floor of maxillary sinus is(9.15 ± 0.49)mm for male and(9.07 ± 0.46)mm for female;the distance of the molar root bifurcation to the buccal alveolar surface is(6.89±0.21)mm for male and(6.63±0.30)mm for female;the distance of the molar root bifurcation to the palatal alveolar surface is(7.52±0.35)mm for male and(7.15±0.32)mm for female;And the average distance of palatal root tip to the floor of maxillary sinus is(2.38 ± 0.69)mm for male,(2.10 ± 0.51)mm for female.[Conclusion]: The results show that the average distance of alveolar ridge to the floor of maxillary sinus is larger than 11 mm,and the measured value for male is larger than female.Thus,the immediate implantation for the maxillary first molar is feasible,and male patients may have a greater initial stability.The average distance of the molar root bifurcation of maxillary first molar to the floor of maxillary sinus is larger than 9mm for both male and female;this meets the available bone height requirements for initial stability of the implant.And the root gap width can also achieve the available bone width requirements for the initial stability of immediate implant;therefore,the root interval alveolar bone could be selected as the preferred implant site for the operation of maxillary first molar immediate implantation.The average distance of the apical palatal root of maxillary first molar to the maxillary sinus is less than 3mm,so it is not recommended to put the implant from the extraction socket of palatal root directly.