| TestⅠClinical follow up for the technique of penetrating the maxillary sinus floorwhen placing implant in atrophic posterior maxillaObjective To observe the clinical prognosis of penetrating the maxillarysinus floor with simultaneous implant placement without grafting material in atrophicposterior maxilla. Methods From October,2002to March,2012,512implants wereplaced in369consecutive patients who need implant treatment in the posterior maxilla.They were classified into two groups: the penetrating maxillary sinus floor group (groupA) and the conventional implant placement group (group B). Totally169implantsbelong to the group Aand343implants belong to the group B. The average follow-upperiod was2.09+1.84years, the longest was8.05years. Then, the successful rates ofthe2groups were calculated respectively. Results No complications occur in group A.The success rate of the group Aand the group B were98.22%and97.79%respectively.The difference was not statistically significant (p>0.05). Conclusion The technique oflimited penetrating the maxillary sinus floor with simultaneous implant placement inatrophic posterior maxilla can be used in the case of the thickness of maxillary sinusfloor over5mm, and this treatment can be used in clinic because of its easier operation,less invasion, lower cost, shorter period of healing and easily accepted by the patients.TestⅡCohort study of the clinical result of the implant penetration the maxillarysinus floorSectioneⅠAnalysis of bone resorption and formation with MS Excel software after implants loadingObjective To discuss the possibility by using the table cell pixel andcalculation function of MS Excel software to measure the different dimensions of theimplant during evidence-based medicine research. Methods Using Excel andradiovisiongraph (RVG) methods respectively to measure the distance of sinusbase-ridge and the protrusion length of implant in the maxillary sinus in68implants,and get the average value. Results The difference of the values of sinus base-ridge andaverage value of the protrusion length of the implant in maxillary sinus which wasgained by Excel and RVG methods respectively does not show statistical signification.Conclusion Utilize the calculation function of Excel software by install thecomputational formula to the table cell previously, and then get the final resultsimmediately by just input the original data. It is an easy and effective method to dealwith the original data, and it can be used in evidence-based medicine research of largesample analysis.SectionⅡCohort study of the clinical result of the implant penetration themaxillary sinus floorObjective To observe prospectively the clinical result of the implantpenetration the maxillary sinus floor by cohort study. Methods From Nov.2002to Feb.2011,241patients with posterior region implant treatment in upper jaw were calculated,375implants were placed,110patients had the experience of penetration the maxillarysinus floor,133implants were placed totally. According to the plan of the Cohort study,after clinical follow-up, X-ray examination, measure the pixel of the bone gaining orloosing which surround the implant by Excel method, variance analysis by SPSS17.0software and calculation of the penetration distance of the sinus floor&endo-sinusbone gain (ESBG)&crestal bone loss (CBL), then evaluate the implant survival andsuccessful rate by life tables method. Results The follow-up rate was98.7%of the133implants, and the average follow-up period was46.7months (4-77months). Thesurvival rate table showed that the accumulative survival rate was98.48%. There are86implants born2years loading,84of them are Straumann implants (Institut Straumann AG, Switzerland), the other2are Anthogyr implants (Anthogyr, France).2implantswere lost before loading. In one case, the distance of sinus base-ridge was3mm, theother was9.4mm. There were no syndrome occurs except one blooding from the noseafter operation in a patient. There were58implants with sufficient X-ray documents,and divided them to3groups according to the distance of sinus base-ridge Group A:<5mm (5implants), Group B:5-8mm (27implants) and Group C:>8mm (26implants).The penetration distance of the sinus floor of these3groups are3.23±1.33mm，2.36±1.36mm and1.48±1.00mm respectively (F=6.152, p <0.05), the value of Group A isgreater than Group C obviously. Mesio ESBG is0.88±1.30mm,0.86±1.35mm and0.20±0.73mm respectively; Distal ESBG is0.81±0.21mm,0.89±1.22mm and0.22±0.88mm respectively; Mesio CBL is-0.96±0.25mm,-1.10±0.97mm and-1.64±0.97mm respectively; Distal CBL is-0.43±0.52mm,-0.62±0.86mm and-0.99±0.94mm respectively. The total bone gaining surround implant at the mesio part is-0.29±1.30mm,0.03±1.59mm and-1.71±1.33mm respectively (F=9.742, p<0.05), GroupC is lower than Group A&B; and at the distal part, the value is-0.44±1.10mm,0.01±1.48mm and-0.14±1.30mm respectively. There is no significant difference of otheritems. Conclusion1) through accurate measurement, precise operation, if the length ofpenetration of the sinus floor is below3mm, the ideal survival and successful rate of theimplant can be expected.2) after loading, the distance of sinus base-ridge has a decreasetrend, the bone quantity of the sinus floor is stable, the average ESBG is0.57±1.09mm,bone absorption mainly occurred at the crest of the implant, average value is1.05±0.96mm mm.3) according to this study, it can be realized that useing the full length ofthe sinus floor and penetration of the sinus floor in a limitation is very safe. It isrecommended that if the length of the sinus floor is over5mm and has good quality, thesinus lift operation can be avoided.TestⅢThe three dimensional finite element analysis for stress distribution ofmaxilla with different implant model under functional loadsObjective: To explore the stress distribution and displacement around different dental implant of the maxilla. Methods: Two three-dimensional finite elementmodel of maxilla were built, one with normal vertical height of bone in the maxillasinus floor and the other with poor vertical height of bone in the same area. Four dentalimplant models were built either, the size of the dental implants are4.1×8.0mm,4.8×8.0mm,4.1×10.0mm and4.8×10.0mm. The4.1×8.0mm and4.8×8.0mm implantswere used in the model with poor vertical height of bone and the tip of that oversteppedthe maxilla sinus floor2.5mm.200N (Newton) force was applied vertically and100Nforce was applied obliquely (45degree) on the dental implants to simulate thefunctional status. Results: No difference was observed between the two models ofmaxilla under vertical loads and little difference was observed between the two modelsof maxilla under oblique loads. Conclusion: Dental implants with relatively shorterlength and larger diameter are qualified for maxilla with poor vertical height of bone inmaxilla sinus areas. |
PDF Full Text Request