Impact of excessive occlusal load on successfully‐osseointegrated dental implants: a literature review

The aim of the present study was to review the available evidence on the response of the peri‐implant bone when subjected to excessive occlusal forces. The search strategy included papers published in English in the Medline database and the Wiley Online Library from January 1991 to December 2011. Experimental or review papers reporting the conditions of the peri‐implant bone of dental implants submitted to excessive occlusal loading in the presence of a controlled oral hygiene regime were eligible for inclusion. The knowledge regarding the response of the peri‐implant bone when the dental implant is excessively loaded is limited, and the level of evidence is poor. With animal experimental studies showing conflicting results, it is unclear whether occlusal overload might cause marginal bone loss or total loss of osseointegration to already osseointegrated dental implants when the applied load exceeds the biologically‐acceptable limit. This biological limit is also unknown. Furthermore, higher remodeling activity of the peri‐implant bone is found around implants subjected to high loading forces.     

Masticatory performance in older subjects with varying degrees of tooth loss

Objectives

The purpose of this study was to establish the factors influencing the masticatory performance of older subjects with varying degrees of tooth loss and associated numbers of posterior occlusal contacts.

Methods

The subjects consisted of 1274 independently living people aged 60 years and over. Individuals with partially or fully edentulous arches without a denture replacement or those having any symptoms related to an oral problem were excluded from the study participants. Masticatory performance, maximal occlusal force and stimulated whole saliva were measured. Subjects were grouped into three categories by posterior occlusal contact, according to the Eichner Index. Group A had contacts in four support zones; group B had one to three zones of contact or contact in the anterior region only; and group C had no support zones at all, although a few teeth could still remain.

Results

The masticatory performance in groups B and C was found to be 81% and 50% of that of group A, respectively. The multiple linear regression analysis showed that in all the groups, occlusal force was significantly associated with masticatory performance. In groups A and B, the number of residual teeth was significantly associated with masticatory performance, whereas in group C, it had no significant relationship with masticatory performance. Salivary flow rate had a significant correlation with masticatory performance only in group C.

Conclusions

Declines in occlusal contact, occlusal force and salivary flow appear to be associated with reduction of masticatory performance in older adults. However, the crucial factors for masticatory performance varied, depending on the phase of occlusal collapse.     

脊柱骨盆矢状面平衡参数对老年单节段骨质疏松压缩性骨折行PKP术后继发椎体骨折的影响

目的探讨脊柱骨盆矢状面平衡参数对老年单节段骨质疏松压缩性骨折(OVCF)行经皮球囊扩张椎体后凸成形术(PKP)术后继发椎体骨折的影响。方法回顾性分析2016年12月-2018年12月在四川省第二中医医院骨伤科确诊并行PKP治疗的128例单节段OVCF患者的临床资料,根据PKP术后是否继发椎体骨折将其分为继发组(n=60)和未继发组(n=68),在站立位全脊柱侧位X线片上测量脊柱骨盆矢状面平衡参数,比较两组手术相关资料、VAS评分、ODI评分、脊柱骨盆矢状面平衡参数。结果两组骨水泥用量差异无统计学意义(t=1.446,P=0.151);两组手术节段、手术入路差异无统计学意义(χ^2=0.187、0.008,P=0.911、0.929)。继发组VAS评分、ODI评分明显高于未继发组(t=5.717、9.935,P=0.000、0.000)。两组胸腰椎后凸角(TLK)、骨盆倾斜角(PT)差异无统计学意义(t=0.953、1.086,P=0.342、0.279)。继发组矢状面偏移(SVA)明显高于未继发组(Z=-9.142,P=0.000),胸椎后凸角(TK)明显高于未继发组(t=3.827,P=0.000),腰椎前凸角(LL)、骶骨倾斜角(SS)、骨盆入射角(PI)明显低于未继发组(t=4.002、4.794、4.078,P=0.000、0.000、0.000)。结论较小SVA、TK及较大LL、SS、PI可减小老年单节段骨质疏松压缩性骨折患者PKP术后继发椎体骨折的概率。     

超声引导下腹横平面阻滞联合氯胺酮麻醉与单纯氯胺酮麻醉用于小儿腹股沟疝手术的临床效果

目的探讨超声引导下腹横平面阻滞联合氯胺酮麻醉与单纯氯胺酮麻醉用于小儿腹股沟疝手术的效果及安全性。 方法选择2018年9月至2020年3月川北医学院附属医院收治的80例腹股沟疝患儿作为研究对象,并按照麻醉方案的不同将患者分为观察组与试验组,每组患儿40例。观察组的麻醉方案为单纯氯胺酮静脉麻醉;试验组的麻醉方案为超声引导下腹横平面阻滞联合氯胺酮麻醉。对比2组患儿不同时间点[切皮前（T0）、切皮后10 min（T1）、切皮后15 min（T2）、探查疝囊（T3）]的生命体征、麻醉质量以及进入麻醉恢复室后不同时间点[进入即刻（T4）、进入后20 min（T5）、进入后40 min（T6）]的疼痛情况和镇静情况,及2组患儿的不良反应情况。 结果试验组患儿T1、T2、T3时心率、平均动脉压均显著低于观察组患儿（P<0.05）;2组患儿麻醉诱导时间对比,差异无统计学意义（P>0.05）;试验组苏醒时间均显著低于观察组患儿（P<0.05）;试验组患儿T4、T5、T6时东安大略儿童医院疼痛量表评分、Watcha镇静评分均显著低于观察组患儿（P<0.05）;试验组患儿的不良反应发生率显著低于观察组患儿（P<0.05）。 结论超声引导下腹横平面阻滞联合氯胺酮麻醉对小儿腹股沟疝手术的麻醉效果显著,其麻醉方案不仅能获得更稳定的需流动力学特征,缩短患儿的麻醉苏醒时间,还能改善患儿术后的疼痛及镇静情况。     

平板探测器-实质血容量检测评价颈动脉内膜剥脱术围术期脑组织血流灌注

目的 总结分析平板探测器(FPD)-实质血容量(PBV)检测技术在颈动脉内膜剥脱术(CEA)患者围术期脑组织灌注评价中应用的可行性及临床价值.方法 连续收治的40例明确诊断为单侧症状性颈内动脉重度狭窄(70％～99％)患者均经复合手术室头颈部经颅多普勒超声和(或)全脑DSA评估并接受CEA手术,术前、术后即刻作FPD-PBV检测,评估脑组织血流灌注变化.结果 FPD-PBV技术可很好地检测CEA围术期患者脑组织血流灌注.40例患者均为单侧症状性颈内动脉起始段重度狭窄(左侧18例,右侧22例),术前患侧脑血流灌注明显低于健侧(P＜0.05).顺利完成CEA术后DSA显示颈内动脉再通良好,颅内分支血流恢复,患侧脑血流灌注较术前增加(P＜0.05),其中22例术后脑灌注改善,但仍低于健侧(＜10％);15例高于健侧(＜5％);3例与健侧相等.术后患侧和健侧脑灌注间差异无统计学意义(P＞0.05).结论 FPD-PBV检测是一种可行的、有较高临床应用价值的成像技术,可用于半定量分析脑灌注变化,为围术期治疗决策和疗效评价提供更多有价值信息.     

腹横肌平面阻滞复合静脉自控镇痛与硬膜外镇痛用于开腹结直肠手术的比较

目的 观察和比较腹横肌平面(transversus abdominis plane,TAP)阻滞复合静脉自控镇痛与连续硬膜外镇痛对开腹结直肠手术患者镇痛和康复的影响. 方法 入选84例开腹结直肠手术患者,采用随机数字表法将患者分为两组:超声引导下TAP阻滞复合静脉自控镇痛组(T组)和连续硬膜外镇痛组(E组),每组42例.主要监测指标为术后48 h VAS评分,同时比较术后补救镇痛药使用率、舒芬太尼消耗量、胃肠道功能恢复时间、早期活动时间、低血压发生率、恶心呕吐发生率、下肢感觉及运动异常、医学康复时间和实际住院时间等. 结果 最终80例患者完成本研究.两组患者术后48 h VAS评分、术后补救镇痛药使用率、胃肠道功能恢复时间、恶心呕吐发生率、医学康复时间和实际住院时间差异均无统计学意义(P＞0.05).与E组比较,T组术后低血压发生率(15％比40％)、早期活动时间[(64±13)h比(91±12)h]、下肢感觉及运动异常(0比10％)、术中及术后舒芬太尼消耗量[(49±11)μg比(43±7)μg及(88±12) μg比(45±5)μg]差异有统计学意义(P＜0.05). 结论 与连续硬膜外术后镇痛比较,TAP阻滞复合静脉自控镇痛能为开腹结直肠手术患者提供相似的镇痛与康复效果,且低血压等并发症发生率更低.     

超声引导腹横肌平面阻滞对剖宫产术后镇痛的影响

目的探讨超声引导腹横肌平面(TAP)阻滞对剖宫产术产妇术后镇痛效果的影响。方法择期于腰-硬联合麻醉下行剖宫产术的产妇80例,ASAⅠ或Ⅱ级,随机均分为两组:腹横肌平面阻滞组(T组)和对照组(C组)。T组于术毕行超声引导双侧TAP阻滞,每侧注射0.5%罗哌卡因20ml,C组不阻滞;两组均行PCIA,于术后2、4、6、8、24h时行静息、运动时VAS评分、Ramsay镇静评分及BCS舒适度评分。记录术后24h内PCIA中舒芬太尼用量;记录产妇满意度及不良反应的发生情况;计算术后24h内PCIA有效按压次数与实际按压次数比(D1/D2)。结果与C组比较,术后2、4、6hT组静息及运动时VAS评分明显降低,BCS舒适度评分明显升高(P0.05)。T组术后24h内PCIA中舒芬太尼用量明显少于C组(P0.05),D1/D2及产妇满意度明显高于C组(P0.05)。两组均未发生恶心、呕吐、皮肤瘙痒、胸闷等不良反应。结论超声引导TAP阻滞减少了产妇在剖宫产术后阿片类镇痛药的使用量,增强了术后镇痛效果,提高了产妇的舒适度和满意度。     

Dynamics of quadrupedal locomotion of monkeys: implications for central control

We characterized the three-dimensional kinematics and dynamics of quadrupedal gait of young adult rhesus and cynomolgus monkeys while they walked with diagonal and lateral gaits at 0.4–1.0 m/s on a treadmill. Rigid bodies on the wrist, ankle, and back were monitored by an optical motion detection system (Optotrak). Kinematic data could be normalized using characteristic stride length, reducing variance due to different gait styles, to emphasize common characteristics of swing and stance parameters among animals. Mean swing phase durations fell as walking speed increased, but the swing phase durations increased at each walking velocity as a linear function of increases in amplitude, thereby following a main sequence relationship. The phase plane trajectories of the swing phases, i.e., plots of the relation of the rising and falling limb velocity to limb position in the sagittal (X–Z) plane, had unique dynamic characteristics. Trajectories were separable at each walking velocity and increases in swing amplitude were linearly related to peak swing velocities, thus comprising main sequences. We infer that the swing phase dynamics are set by central neural mechanisms at the onset of the swing phases according to the intended amplitude, which in turn is based on the walking velocity in the stance phases. From the many dynamic similarities between swing phases and rapid eye movements, we further suggest that the swing phases may be generated by neural mechanisms similar to those that produce saccades and quick phases of nystagmus from a signal related to sensed or desired walking velocity. Grants: This work was supported by National Institute of Health Grants EY11812, EY04148, DC05204, and EY01867.     

An investigation of overeruption of posterior teeth with partial occlusal contact

The need and demand for replacement of missing posterior teeth may increase as the UK population is predicted to be at least partially dentate for life. Replacement with either fixed or removable prostheses may be indicated, and the tooth positional changes of adjacent or opposing teeth may require consideration. The objectives of this study are to: (1) Investigate the extent of overeruption associated with partially opposed posterior teeth; (2) Determine if overeruption is associated with tipping of the partially opposed tooth and examine the extent of tip. Ninety-one patients with either partially or completely unopposed posterior teeth were included in the study. For each group the extent of overeruption of the tooth was measured. Differences in the extent of overeruption and tipping were analysed. Correlations between the presence of partial tooth contact and the extent of overeruption and degree of tipping of the unopposed tooth were analysed. There was no significant difference in the extent of overeruption between the unopposed and partially opposed groups. The partially opposed teeth displayed a greater degree of tipping than the unopposed group. There was no significant correlation between the extent of overeruption and the degree of tipping, nor between the extent of overeruption and the presence of partial tooth contact. There was, a significant correlation between the degree of tooth tip and the presence of partial tooth contact. (1) Partial tooth contact does not appear to prevent or reduce overeruption; (2) Partially opposed teeth show an increased degree of tip relative to teeth with complete lack of occlusal contact. The findings suggest that partial tooth contact should not be relied on clinically to maintain vertical tooth position.