Application Of Vertical Bone Augmentation In Posterior Maxilla Supported By Bone Level Implants And Healing Abutments

Objective:The aim of this study is to observe the effect of bone augmentation in the case of vertical bone defects in posterior maxilla supported by bone level implants and healing abutments.The feasibility of vertical bone augmentation in posterior maxilla supported by bone level implants and healing abutments was investigated to provide some clinical reference evidence for the implementation of bone augmentation and simultaneous implant placement for mild vertical bone defects in posterior maxilla.Method:The study design was a prospective study which included 13 patients,5 males and8 females,aged 27 ～ 69 years,with a mean of 49.82 ± 12.16 years,all of which diagnosed with maxillary dentition defect and needed implant restoration in the Department of Stomatology of the Third Affiliated Hospital of Guangzhou Medical University from October 2021 ～ March 2022.A total of 18 implant sites were obtained.The inclusion criteria were: no systemic or local contraindications to implant surgery;a residual bone heigh(RBH)of 5.50 mm ～ 9.00 mm from the floor of the maxillary sinus to the top of the alveolar ridge measured by cone beam computed tomography(CBCT);alveolar bone width ≥ 6.00 mm;and a crown height space(CHS)≥ 8.00 mm.In this study,bone level implants were placed in the implant sites and healing abutments were placed to support the vertical osteogenic space.A small amount of vertical bone augmentation was performed by GBR at the same time,and the implant crowns were restored 6 months after the surgery.CBCT were taken preoperatively,immediately postoperatively,6 months postoperatively,and 12 months postoperatively to measure the vertical bone height at the implant sites at each point of time.The primary observation in this study was the height of vertical bone gain.Secondary observations included: the success rate of the implant;implant stability quotient(ISQ);peri-implant soft tissue condition;and restorative complications.SPSS 26 and Graph Pad Prism 9.4.1software were used for statistical and analytical analysis of the observed indices.Kolmogorov-Smirnov test was performed to evaluate the distribution of the data normality.If the data conformed to a normal distribution,the t-test would be performed;if they did not follow a normal distribution,the Mann-Whitney U test would be chosen.(P < 0.05 was set as statistically significant;"ns" indicates no statistical significance).Results:1.A total of 18 implants were implanted in the 13 patients included in this study,of which one implant was removed(failed due to infection),with an implant success rate of 94.44% at 12 months postoperatively.2.(1)Among the 17 remaining implants,successful bone augmentation was achieved in 14 cases 12 months after surgery,with bone height stabilized at or above the implant level;good bone augmentation was achieved in 3 cases,with the presence of 0.30 ～ 1.10 mm implant threads exposed in the soft tissue but not in the oral cavity,and solid implants.(2)The bone gain was 2.14± 0.32 mm for 6 months,and 2.05 ± 0.35 mm for 12 months,respectively after surgery.The two-sample t-test was performed and a P value of 0.478 was obtained.There was no statistical difference between the two groups(P > 0.05),indicating that there was no significant change in the height of bone gain at 6 months postoperatively and 12 months postoperatively,and the bone gain effect was stable.3.The modified plaque index(m PLI)for peri-implant soft tissue health evaluation was 1.35 ± 0.70.The modified sulcus bleeding index(m SBI)was 0.76 ± 0.75.The probing depth(PD)was 2.65 ± 0.70 mm for the proximal mid PD,2.76 ± 0.66 mm for the distal mid PD,2.29 ± 0.47 mm for the buccal PD,and 2.41 ± 0.51 mm for the palatal PD.No sites showed probing of pus overflow abscesses.4.At 12-month postoperative follow-up,no loosening or fracture of the screws and restorative abutments in the implant superstructure was observed in the 17 implant prostheses studied;there were no complications of crown loosening or chipping.Six months after the superstructure was restored and functionally loaded,there was no statistically significant difference in bone gain(P > 0.05)compared to the immediate superstructure restoration(6 months postoperatively),indicating that there was no significant change in bone height after the superstructure restoration and that the restoration was effective.Conclusion:The implant connection to the healing abutment is used as a "support pole" to obtain a certain amount of bone height,so that implant placement can achieve good results in posterior maxilla where the vertical bone height is mildly insufficient,without the need for more complex bone augmentation.This procedure is simple,minimally invasive,and easy to implement in clinical practice.