颧种植体支持式赝复体修复单侧上颌骨缺损的临床应用及生物力学评价

The clinical application and biomechanical analysis of zygomatic implant supported prostheses in unilateral maxillary defect restoration

目的探讨颧种植体支持式赝复体(ZIP)在修复单侧上颌骨缺损中的临床应用并分析其生物力学特点,为临床治疗提供理论依据。方法选取2016年1月至2018年6月上海交通大学医学院附属第九人民医院收治的上颌骨缺损患者。纳入标准:单侧上颌骨缺损,年龄18~70岁,无全身慢性系统性疾病,无放疗史,口内余留牙列基本完整,无中、重度牙周炎,牙齿无松动,无明显错[牙合]。于患侧颧骨植入颧种植体2颗,即刻佩戴传统可摘式赝复体(RP),术后6~12个月完成ZIP修复,通过日常生活牙科影响量表(DIDL)对患者佩戴RP和ZIP后的主观感受进行生活质量评价,从外观、疼痛、舒适度、咀嚼效率和一般性能5个方面进行评分,结果采用独立样本t检验进行统计分析。利用1例25岁正常男性志愿者头颅CT数据建立半侧上颌骨缺失的三维有限元模型,并绘制颧种植体和赝复体模型,在该复合模型中对赝复体的义齿咬合面加载150 N垂直力模拟咬合力,并分析颧种植体、赝复体卡环、腭板、基牙等部位的应力分布情况及应力集中点,比较RP修复和ZIP修复后的差异。结果共纳入8例单侧上颌骨缺损患者,男5例,女3例,年龄18~63岁,平均48.9岁。8例患者共植入颧种植体16颗,术后9~10个月全部完成ZIP修复。DIDL量表结果显示,ZIP在外观、舒适度、咀嚼效率和一般性能这4项指标中得分分别为(0.79±0.15)、(0.70±0.15)、(0.63±0.24)、(0.73±0.13)分,均明显高于RP的(-0.41±0.22)、(0.35±0.22)、(-0.09±0.34)、(0.30±0.19)分,而ZIP在疼痛指标中的得分为(0.29±0.15)分,低于RP的(0.48±0.23)分,除疼痛指标外,其余指标差异均具有统计学意义(P<0.05)。生物力学分析证明,ZIP与RP相比,应力主要由颧种植体承担,腭板、卡环、基牙等处的应力明显减小,且分布更加均匀,无明显应力集中点。结论ZIP可改善外观、降低不适感、提高咀嚼效率,是修复单侧上颌骨缺损较好的方法。

Objective To evaluate the clinical application and biomechanical characteristics of zygomatic implant supported prosthesis(ZIP)in restoring unilateral maxillary defect and to provide theoretical support for clinical treatment.Methods A total of 8 patients with unilateral maxillary defect admitted to the Ninth People’s Hospital,Shanghai Jiao Tong University School of Medicine from January 2016 to June 2018 were selected.Inclusion criteria:unilateral maxillary defect,18 to 70 years old,no systemic chronic disease,no radiotherapy history,healthy residual dentition,no moderate to severe periodontitis,no loose teeth,and no obvious malocclusion.Two zygomatic implants were implanted on the affected side,and the defects were restored with removable prostheses(RP)immediately after the operation.ZIP was manufactured and placed 6-12 months after implantation.And then,the quality of life after wearing RP and ZIP was evaluated with Dental Impact on Daily Living scale(DIDL).The subjective feelings of patients were evaluated from five aspects of appearance,pain,oral comfort,eating and chewing and general performance.The results were statistically analyzed by independent sample t test.A three dimension model of skull was established with the CT data of a 25-year-old healthy male and the models of zygomatic implants and prosthesis were constructed at the same time.In this composite model,a 150 N vertical force was loaded on the occlusal surface of the prosthetic prosthesis to simulate the bite force,and the stress distribution and concentration points of the zygomatic implant,prosthetic clasps,palatal plate,abutment and other parts were analyzed.The differences between RP and ZIP restoration were compared.Results A total of 8 patients with unilateral maxillary defect were selected,including 5 males and 3 females,aged from 18 to 63 years,with an average of 48.9 years.A total of 16 zygomatic implants were implanted in 8 patients,and ZIP repair was completed 9-10 months after operation.The result of DIDL scale showed that,in terms of appearance,oral comfort,eating and chewing,general performance,the score of ZIP group was 0.79±0.15,0.70±0.15,0.63±0.24,0.73±0.13 respectively,all of which were significantly higher than those of RP group-0.41±0.22,0.35±0.22,-0.09±0.34,0.30±0.19 respectively.Nevertheless,the score of ZIP group in terms of pain was 0.29±0.15,which was lower than that of RP group(0.48±0.23).Except for pain,the other differences were statistically significant(P<0.05).The biomechanical analysis showed that,compared with RP group,the stress of ZIP was distributed mainly in the zygomatic implants.And the stress of palatal plates,clasps and abutments was reduced significantly and distributed evenly,with no obviously stress concentration point.Conclusions ZIP can improve appearance,reduce discomfort and increase mastication efficiency.It is a better choice for unilateral maxillary defect restoration.