| With the development of implant surgery and the continuous innovation of implant design,the indication of implant teeth is expanding.Implant teeth have gradually become a widely used and highly predictable clinical solution.To reconstruct the posterior atrophic jaw with bone insufficiency,scholars have invented and continuously improved various bone augmentation techniques(including maxillary sinus elevation,guided bone regeneration,bone grafting,distraction osteogenesis,etc.)and implant designs(including short implants,titled implants,zygomatic implants,etc.).A large number of comparative studies have been designed to evaluate the clinical effects of various protocols.In this paper,we focus on the following three aspects of implant reconstruction in the posterior atrophic jaws.1)Meta-analysis based on randomized controlled trial(RCT)was used to compare the effect of alveolar ridge augmentation and shorter implant in atrophic jaws.The outcomes included implant survival rate,incidence of complications and peri-implant marginal bone loss.2)Meta-analysis based on randomized controlled trial(RCT)was used to compare the clinical efficacy of maxillary sinus augmentation with bone grafts and without bone grafts.The outcome measures included implant survival rate,new bone formation in maxillary sinus,peri-implant marginal bone loss,and new bone density.3)Retrospective analysis was applied to observe the radiological changes after maxillary sinus elevation combined with short implants and analyze the possible related factors affecting the new bone formation in the maxillary sinus and the marginal bone loss around the implant.Part 1 Alveolar ridge augmentation compared with shorter implants in atrophic jaws:a meta-analysis based on randomized controlled trialsObjective:To compare two therapeutic options-augmentation of the alveolar ridge and shorter implants-in the treatment of atrophic jaws.Methods:To fulfill the preset inclusion criteria,we searched the electronic databases PubMed,EMBASE through OVID and the Cochrane Central Register of Controlled Trials(CENTRAL).Two people were responsible for screening,extraction of data,and assessment of quality.Meanwhile,several dental journals were hand searched.The meta-analysis was made with the aid of Review Manager(RevMan)5.1.The quality of evidence was assessed using the Grades of Recommendation,Assessment,Development,and Evaluation(GRADE).Results:The electronic database and manual search yield 2082 studies.After screening the titles,abstract and the full-text,and cross-matched with the inclusion criteria,only 10 studies were eligible.A total of 1175 implants were investigated,which included 605 implants in the augmentation group and 570 implants in the shorter implants group.There was no significant difference in implant survival between alveolar ridge augmentation group and shorter implants group,with a RR of 0.99(95%confidence interval(CI)0.96 to 1.01,P=0.29).Alveolar ridge augmentation group revealed significantly higher incidence of complications than shorter implants group,the RR was 2.23(95%Cl 1.16 to 4.26,P=0.02).Meta-analysis also revealed statistically more changes in marginal bone level,the RR was 0.19(95%CI 0.11 to 0.27,P<0.00001)in the augmentation group.According to the GRADE,the evidence levels for implant survivals,incidence of complications and marginal bone loss were high.Conclusion:In atrophic jaws with enough residual bone,shorter implants without augmentation might be the first choice as they seem to be associated with the same implant survivals,less complications and peri-implant bone loss.Part 2 Maxillary sinus floor augmentation with grafts versus without grafts in atrophic maxilla:a meta-analysis based on randomized controlled trialsObjective:To systematically compare the effectiveness of sinus floor augmentation with and without grafts in atrophic maxilla.Methods:To fulfill the preset inclusion criteria,we searched the electronic databases PubMed,EMBASE through OVID and CENTRAL.Two people were responsible for screening,extraction of data,and assessment of quality.Meanwhile,several dental journals were hand searched.The meta-analysis was made with the aid of Review Manager(RevMan)5.1.The quality of evidence was assessed using the GRADEprofiler.Results:The electronic database and manual search yield 707 studies.After screening the titles,abstract and the full-text,and cross-matched with the inclusion criteria,only 5 studies were eligible.A total of 336 implants were investigated,which included 214 implants in the sinus augmentation with bone grafting group and 122 implants in the sinus augmentation without bone grafting group.No significant differences were found between the two groups in implant survivals,with a RR of 1.00(95%CI 0.96 to 1.04,P=0.94).There was significantly more endo-sinus bone gain in the sinus augmentation with bone grafting group than no grafting group,with a RR of-0.69(95%CI-1.28 to-0.11,P=0.02).Meta-analysis also revealed there were no significant differences in the marginal bone loss and the new bone density between the two groups(P=0.73 and 0.54).According to the GRADE,the levels of evidence were moderate(implants survivals and marginal bone loss),low(endo-sinus bone gain),and very low(new bone density).Conclusion:Based on the evidence,we could get a preliminary conclusion there were no significant differences between maxillary sinus augmentation with and without grafts in short-term implant survivals.PART 3:Radiological analysis after osteotome sinus floor elevation combined with short implants:an 18-month retrospective studyObjective:The purpose of this study was to evaluate the radiological changes after osteotome sinus floor elevation(OSFE)and to analyze the possible related factors affecting the new bone formation in the maxillary sinus and the marginal bone loss around the implant.Material and Methods:40 patients(including 51 implants)who underwent OSFE combined with short implants and finally reconstructed with single crown 6 months after surgery were analyzed.The panoramic radiographs were taken immediately after,6 months after,12 months after,and 18 months after OSFE.Correlation analysis and partial correlation analysis were used to analyze the factors related to the new bone formation in maxillary sinus and marginal bone loss around implants after maxillary sinus elevation.Results:After 18-month follow-up,the mean endo-sinus bone gain(ESBG)was 2.55±2.24mm(ranged from 0.1 to 8.6mm),the mean marginal bone loss(MBL)was 0.69±0.61mm.There was no significant correlation between residual bone height(RBH)and ESBG,and partial correlation coefficient was-0.143(P=0.328).Partial correlation analysis also showed that there were positive correlations between implant protrusion length in sinus elevation procedure(IPL)/whether to graft and ESBG,and the partial correlation coefficients were 0.560(P=0.000)and 0.596(P=0.000)separately.There was no significant correlation between crown/implant ratio and MBL,the correlation coefficient and partial correlation coefficient were 0.173(P=0.224)and 0.006(P=0.966).Conclusion:IPL and application of simultaneous grafts have positive correlation with new bone formation in sinus after OSFE.Short implants combined with OSFE can be a good solution for reconstruction of atrophic posterior maxillary,and appropriate bone grafts can yield a predicable outcome. |
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