| Objectives To study bovine hydroxyapatite(Bio-oss),synthetic hydroxyapatite(HA),and 10% strontium-dopped brushite(10% Sr-DCPD)osteogenesis and osseointegration of titanium implants after maxillary sinus floor elevation.It also provides experimental basis for the selection of bone substitute materials for clinical maxillary sinus floor elevation with simultaneous dental implantation.Methods A total of 27 female New Zealand white rabbits(54 sinuses)were involved and the maxillary sinus was implanted at the same time.The maxillary sinuses were randomly divided into A,B,and C groups(18 sides in each group),and different materials were implanted on both sides of the maxillary sinus of each rabbit.Animals were sacrificed at 2,4,and 12 w after surgery,each group with 9 maxillary sinuses.Specimens were harvested and gross specimen observation,soft X-ray and Micro-CT were performed to compare the effect on bone regeneration,maxillary sinus elevation space maintenance and osseointegration of implants.Results 1 Gross specimen observation showed that the bone windows were not well healed in group A(Bio-oss)and group B(synthetic HA)at 4w,until at 12 w bone windows were still mixed with bone substitute material particles;while in group C(10% strontiumdopped brushite)4W,the bone windows have formed intact bone plates,suggesting that it can promote bone window healing more than Bio-oss and synthetic HA;2 Soft X-ray observation showed that in all time points,the area of maxillary sinus elevation was larger in group A and B,and the implants were all convex in the sinus cavity.In group C it was smaller tha that of A and B.Group,and the part of the implants in contact with the sinus mucosa is concave.In group A and B decreased over time,but they decreased significantly.Compared with 12 w and 2w,they decreased by 8.30% and 11.53%,respectively;while in group C they decreased significantly.Compared with 2w,the decrease was 74.19%.At 2w,4w and 12 w,the area of group C was only 66.29%,34.89% and 18.65% of that of group A.The above results suggest that group A and group B materials absorb slowly and can effectively maintain the maxillary sinus lifting volume.However,group C absorbs faster and can not effectively maintain maxillary sinus elevation volume;The gray value of the ascending region in group A and group B increased significantly over time,and it increased by 18.82% and 15.38% compared with 2w at 12w(P>0.05).However,the gray value in group C decreased gradually,and at 12 w,compared with 2w,there was a decrease of 42.59%(P<0.05)and 63.74%(P<0.05).The above results suggest that over time both group A and group B are significantly absorbed at the same time with new bone formation,and group B has the best osteogenic effect;and group C although new bone is formed,the material absorbs rapidly and thus the bone gray value decreases;3 Micro-CT examination showed that at 2,4,and 12 w,the three groups of maxillary sinus elevation volume(TV)and bone substitute material percentage(BMT)gradually decreased over time,in which group A decreased the slowest,group B(P>0.05)next,the fastest in group C(P<0.05);in 12 w and 2w,the maxillary sinus elevation volume(TV)in groups A,B,and C decreased respectively by 9.98% ? 17.99%(P>0.05)and79.64%(P<0.05);suggesting that the absorption of group A and group B was slower,and the maxillary sinus elevation volume maintained better;while group C absorbed faster,and the maxillary sinus elevation volume remained poor;At 2w and 4w,the new bone formation was the fastest in the maxillary sinus elevation region in group C,and it was almost completely autologous bone repair at 4w;bone regeneration parameters percentage of new bone(NBT),percentage of mature bone(MBT),trabecular bone The thickness(Tb.Th)and trabecular number(Tb N)in group C were also significantly higher than those in group A and B(P<0.05).At 12 w,except that Tb.Th was highest in group C,NBT,MBTand Tb Nwere highest in group B,followed by group A,and lowest in group C(P>0.05).The above results show that 10% strontiumdopped brushite promotes bone regeneration in the early stage of maxillary sinus elevation(2w,4w),but by 12 w,the effect is not as good as that of Bio-oss and synthetic HA;At the time points of 2w,4w,and 12 w,the IBCR was highest in group B,followed by group A,and lowest in group C(P<0.05),but there was no significant difference between group B and group A(P>0.05).The above results indicate that both B group and A group are more conducive to implant osseointegration than C group during the period of maxillary sinus elevation bone regeneration.,and best effect in group B.Conclusions 1 Bio-oss,synthetic hydroxyapatite(HA),10% strontium-dopped brushite bone substitute materials can promote bone tissue regeneration and bone osseointegration during maxillary sinus elevation;2 The biodegradation rate of Bio-oss and synthetic HA is slower in vivo,and can effectively maintain the volume of the maxillary sinus elevation.It can be used alone.However,the bone formation rate is slower and the bone regeneration time is longer;3 The formation of new bone formation can be rapidly induced by 10% strontium-dopped brushite,but the degradation rate is fast,and the volume of maxillary sinus elevation can not be effectively maintained by single application;4 Bio-oss and synthetic HA can promote implant-bone contact in the maxillary sinus elevation,more effectively than 10% strontium-dopped brushite,and the effect of synthetic HA is better than that of Bio-oss. |
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