Korean larch(Larix olgensis)is one of the main tree species for aff orestation and timber production in northeast China.However,its timber quality and growth ability are largely infl uenced by crown size,structure and...Korean larch(Larix olgensis)is one of the main tree species for aff orestation and timber production in northeast China.However,its timber quality and growth ability are largely infl uenced by crown size,structure and shape.The majority of crown models are static models based on tree size and stand characteristics from temporary sample plots,but crown dynamic models has seldom been constructed.Therefore,this study aimed to develop height to crown base(HCB)and crown length(CL)dynamic models using the branch mortality technique for a Korean larch plantation.The nonlinear mixed-eff ects model with random eff ects,variance functions and correlation structures,was used to build HCB and CL dynamic models.The data were obtained from 95 sample trees of 19 plots in Meng JiaGang forest farm in Northeast China.The results showed that HCB progressively increases as tree age,tree height growth(HT growth)and diameter at breast height growth(DBH growth).The CL was increased with tree age in 20 years ago,and subsequently stabilized.HT growth,DBH growth stand basal area(BAS)and crown competition factor(CCF)signifi cantly infl uenced HCB and CL.The HCB was positively correlated with BAS,HT growth and DBH growth,but negatively correlated with CCF.The CL was positively correlated with BAS and CCF,but negatively correlated with DBH growth.Model fi tting and validation confi rmed that the mixed-eff ects model considering the stand and tree level random eff ects was accurate and reliable for predicting the HCB and CL dynamics.However,the models involving adding variance functions and time series correlation structure could not completely remove heterogeneity and autocorrelation,and the fi tting precision of the models was reduced.Therefore,from the point of view of application,we should take care to avoid setting up over-complex models.The HCB and CL dynamic models in our study may also be incorporated into stand growth and yield model systems in China.展开更多
目的:对比高嵌体与全冠在修复牙体缺损中的美学效果及预后。方法:选取2020年6月-2022年1月笔者医院收治的牙体缺损患者120例(共229颗患牙),采用随机数字法分为对照组(60例,113颗患牙)和观察组(60例,116颗患牙),对照组采用常规全瓷冠修...目的:对比高嵌体与全冠在修复牙体缺损中的美学效果及预后。方法:选取2020年6月-2022年1月笔者医院收治的牙体缺损患者120例(共229颗患牙),采用随机数字法分为对照组(60例,113颗患牙)和观察组(60例,116颗患牙),对照组采用常规全瓷冠修复治疗,观察组采用CAD/CAM全瓷高嵌体修复治疗,观察两组的修复时间(备牙时间、取模时间和总体操作时间),治疗后第6个月、12个月及18个月的修复效果,以及治疗前、治疗后第3个月牙周指标及龈沟液生化指标[C反应蛋白(C-reactive protein,CRP)、人CXC趋化因子配体16(CXC chemokine ligand 16,CXCL16)、白细胞介素1β(Interleukin-1β,IL-1β)]变化,对比两组牙齿美观满意度。结果:观察组备牙时间、取模时间和总体操作时间均显著低于对照组(P<0.05);观察组、对照组治疗后第6个月、12个月、18个月修复优良率分别为100% vs 100%、97.41% vs 85.84%、96.55% vs 83.19%,两组治疗后12、18个月比较差异有统计学意义(P<0.05);治疗后第3个月,两组出血指数(Bleeding index,BI)、菌斑指数(Plaque index,PLI)、牙龈指数(Gingival index,GI)及龈沟液CRP、CXCL16、IL-1β水平均显著降低(P<0.05),且观察组显著低于对照组(P<0.05),两组咀嚼能力显著升高,且观察组显著高于对照组(均P<0.05);观察组患者对修复体满意度(98.34%)显著高于对照组(81.67%)(P<0.05)。结论:CAD/CAM全瓷高嵌体技术应用于修复牙体缺损临床效果显著,可明显改善牙周情况及炎症反应,远期修复效果好,美观度高,患者满意度高,值得临床推广应用。展开更多
基金supported by the National Key Research and Development Program of China(2017YFD0600401)the Fundamental Research Funds for the Central Universities(2572019CP08)
文摘Korean larch(Larix olgensis)is one of the main tree species for aff orestation and timber production in northeast China.However,its timber quality and growth ability are largely infl uenced by crown size,structure and shape.The majority of crown models are static models based on tree size and stand characteristics from temporary sample plots,but crown dynamic models has seldom been constructed.Therefore,this study aimed to develop height to crown base(HCB)and crown length(CL)dynamic models using the branch mortality technique for a Korean larch plantation.The nonlinear mixed-eff ects model with random eff ects,variance functions and correlation structures,was used to build HCB and CL dynamic models.The data were obtained from 95 sample trees of 19 plots in Meng JiaGang forest farm in Northeast China.The results showed that HCB progressively increases as tree age,tree height growth(HT growth)and diameter at breast height growth(DBH growth).The CL was increased with tree age in 20 years ago,and subsequently stabilized.HT growth,DBH growth stand basal area(BAS)and crown competition factor(CCF)signifi cantly infl uenced HCB and CL.The HCB was positively correlated with BAS,HT growth and DBH growth,but negatively correlated with CCF.The CL was positively correlated with BAS and CCF,but negatively correlated with DBH growth.Model fi tting and validation confi rmed that the mixed-eff ects model considering the stand and tree level random eff ects was accurate and reliable for predicting the HCB and CL dynamics.However,the models involving adding variance functions and time series correlation structure could not completely remove heterogeneity and autocorrelation,and the fi tting precision of the models was reduced.Therefore,from the point of view of application,we should take care to avoid setting up over-complex models.The HCB and CL dynamic models in our study may also be incorporated into stand growth and yield model systems in China.
文摘目的:对比高嵌体与全冠在修复牙体缺损中的美学效果及预后。方法:选取2020年6月-2022年1月笔者医院收治的牙体缺损患者120例(共229颗患牙),采用随机数字法分为对照组(60例,113颗患牙)和观察组(60例,116颗患牙),对照组采用常规全瓷冠修复治疗,观察组采用CAD/CAM全瓷高嵌体修复治疗,观察两组的修复时间(备牙时间、取模时间和总体操作时间),治疗后第6个月、12个月及18个月的修复效果,以及治疗前、治疗后第3个月牙周指标及龈沟液生化指标[C反应蛋白(C-reactive protein,CRP)、人CXC趋化因子配体16(CXC chemokine ligand 16,CXCL16)、白细胞介素1β(Interleukin-1β,IL-1β)]变化,对比两组牙齿美观满意度。结果:观察组备牙时间、取模时间和总体操作时间均显著低于对照组(P<0.05);观察组、对照组治疗后第6个月、12个月、18个月修复优良率分别为100% vs 100%、97.41% vs 85.84%、96.55% vs 83.19%,两组治疗后12、18个月比较差异有统计学意义(P<0.05);治疗后第3个月,两组出血指数(Bleeding index,BI)、菌斑指数(Plaque index,PLI)、牙龈指数(Gingival index,GI)及龈沟液CRP、CXCL16、IL-1β水平均显著降低(P<0.05),且观察组显著低于对照组(P<0.05),两组咀嚼能力显著升高,且观察组显著高于对照组(均P<0.05);观察组患者对修复体满意度(98.34%)显著高于对照组(81.67%)(P<0.05)。结论:CAD/CAM全瓷高嵌体技术应用于修复牙体缺损临床效果显著,可明显改善牙周情况及炎症反应,远期修复效果好,美观度高,患者满意度高,值得临床推广应用。
