动态载荷下种植体位置和直径对悬臂梁种植固定义齿应力影响的三维有限元研究

目的 应用三维有限元法分析动态加载下种植体植入位置和直径对悬臂梁种植固定义齿应力的影响。方法 建立左下颌第二前磨牙、第一磨牙、第二磨牙缺失种植固定义齿的三维有限元模型,远中种植体的位置和直径保持不变;近中种植体依次向远中移动形成中轴与第一前磨牙远中面距离D分别为5.5、8.0、10.5、13.0 mm的悬臂梁种植固定义齿,分别采用4.1和4.8 mm两种直径的种植体;以250 N 牙合力模拟咀嚼周期0.875 s的动态载荷加载于颊尖和舌尖上,应用有限元分析软件MSC.Marc和Partran分析种植体-骨组织界面的Von Mises应力情况。结果 随着近中种植体逐渐向远中移动,近远中种植体Von Mises应力均有不同程度增高,近中种植体中轴与第一前磨牙远中面距离D≤8.0 mm范围内种植体最大Von Mises应力增幅缓和,D>8.0 mm时应力急剧加大;近中种植体直径增大,则近远中种植体的应力减小;各加载阶段最大Von Mises应力均处于近远中种植体颈部与皮质骨交界处;斜向加载种植体应力显著大于垂直加载。结论 种植体植入位置是影响悬臂梁种植固定义齿应力的重要因素,悬臂梁长度不超过前磨牙宽度时行种植固定义齿设计是可行的,直径的选择要考虑骨量和悬臂梁长度双重因素。     

The influence of medial implant location in three-unit posterior cantilever fixed partial dentures on stress distribution in surrounding mandibular bone

This study examined the influence of medial implant location in three-unit posterior cantilever fixed partial dentures (FPDs) on stress distribution in mandibular bone surrounding two implants. A three-dimensional finite element model that included three-unit FPD and two cylindrical-type implants (4 mm in diameter and 10 mm in length) osseointegrated in the posterior mandible, was digitized. Five different models were created according to the medial implant location between the missing second premolar and the first molar location. The distal implant was fixed at the missing second molar location. Oblique bite force of 100 N at 30 degrees buccal to the vertical direction was directed on each of three artificial teeth, respectively and simultaneously, while the lower surface of the mandible was fixed. The maximum equivalent stress in the cortical and the trabecular bone generally increased as the medial implant shifted to a distal position. Under the simultaneous bite force, relatively low maximum stresses within the cortical bone: between 55 MPa and 57 MPa, were shown in the models with the medial implant placed within the range of one implant diameter from the most medial position, while higher maximum stresses: between 64 MPa and 73 MPa, were demonstrated with more distally placed medial implants. The results suggest that reasonably low mechanical stress in the surrounding bone may be assured when the medial implant is placed in the range between the missing second premolar position and one implant diameter distal from that location.     

Finite element analysis of fixed partial denture replacement

The purpose of this study was to investigate, by means of the finite element method the mechanical behaviour of three designs of fixed partial denture (FPD) for the replacement of the maxillary first premolar in shortened dental arch therapy. Two-dimensional, linear, static finite element analyses were carried out to investigate the biomechanics of the FPDs and their supporting structures under different scenarios of occlusal loading. Displacement and stress distribution for each design of FPD were examined, with particular attention being paid to the stress variations along the retainer-abutment--and the periodontal ligament-bone interfaces. The results indicated that displacement and maximum principal stresses in the fixed-fixed, three-unit FPD were substantially less than those in the two-unit cantilever FPDs. Of the two cantilever FPDs investigated, the distal cantilever design was found to suffer less displacement and stresses than the mesial cantilever design under similar conditions of loading. The highest values for maximum principal stress in the cantilever FPDs were found within the connector between the pontic and the retainer, and within the periodontal ligament and adjacent bone on the aspect of the retainer away from the pontic.     

Role of implant configurations supporting three‐unit fixed partial denture on mandibular bone response: biological‐data‐based finite element study

Implant‐supported fixed partial denture with cantilever extension can transfer the excessive load to the bone around implants and stress/strain concentration potentially leading to bone resorption. This study investigated the effects of implant configurations supporting three‐unit fixed partial denture (FPD) on the stress and strain distribution in the peri‐implant bone by combining clinically measured time‐dependent loading data and finite element (FE) analysis. A 3‐dimensional mandibular model was constructed based on computed tomography (CT) images. Four different configurations of implants supporting 3‐unit FPDs, namely three implant‐supported FPD, conventional three‐unit bridge FPD, distal cantilever FPD and mesial cantilever FPD, were modelled. The FPDs were virtually inserted to the molar area in the mandibular FE models. The FPDs were loaded according to time‐dependent in vivo‐measured 3‐dimensional loading data during chewing. The von Mises stress (VMS) and equivalent strain (EQS) in peri‐implant bone regions were evaluated as mechanical stimuli. During the chewing cycles, the regions near implant necks and bottom apexes experienced high VMS and EQS than the middle regions in all implant‐supported FPD configurations. Higher VMS and EQS values were also observed at the implant neck region adjacent to the cantilever extension in the cantilevered configurations. The patient‐specific dynamic loading data and CT‐based reconstruction of full 3D mandibular allowed us to model the biomechanical responses more realistically. The results provided data for clinical assessment of implant configuration to improve longevity and reliability of the implant‐supported FPD restoration.     

Three-dimensional finite-element analysis of functional stresses in different bone locations produced by implants placed in the maxillary posterior region of the sinus floor

STATEMENT OF PROBLEM: Implants placed in the posterior maxilla have lower success rates compared to implants placed in other oral regions. Inadequate bone levels have been suggested as a reason for this differential success rate. PURPOSE: The purpose of this study was to determine the amount and localization of functional stresses in implants and adjacent bone locations when the implants were placed in the posterior maxilla in proximity to the sinus using finite element analysis (FEA). MATERIAL AND METHODS: A 3-dimensional finite element model of a maxillary posterior section of bone (Type 3) was used in this study. Different bony dimensions were generated to perform nonlinear calculations. A single-piece 4.1x10-mm screw-shaped dental implant system (ITI solid implant) was modeled and inserted into atrophic maxillary models with crestal bone heights of 4, 5, 7, 10, or 13 mm. In some models the implant penetrated the sinus floor. Cobalt-Chromium (Wiron 99) was used as the crown framework material placed onto the implant, and porcelain was used for occlusal surface of the crown. A total average occlusal force (vertical load) of 300 N was applied at the palatal cusp (150 N) and mesial fossa (150 N) of the crown. The implant and superstructure were simulated in finite element software (Pro/Engineer 2000i program). RESULTS: For the porcelain superstructure for bone levels, maximum von Mises stress values were observed on the mesial fossae and palatal cusp. For the bone structure, the maximum von Mises stress values were observed in the palatal cortical bone adjacent to the implant neck. There was no stress within the spongy bone. High stresses occurred within the implants for all bone levels. CONCLUSION: The maximum von Mises stresses in the implants were localized in the neck of implants for 4- and 5-mm bone levels, but for 7-, 10-, and 13-mm bone levels more even stresses occurred within the implants.     

The influence of occlusal loading location on stresses transferred to implant-supported prostheses and supporting bone: A three-dimensional finite element study

STATEMENT OF PROBLEM: Information about the influence of occlusal loading by location on the stress distribution in an implant-supported fixed partial denture and supporting bone tissue is limited. PURPOSE: The purpose of this study was to investigate the effect of loading at 1 to 3 different locations on the occlusal surface of a tooth on the stress distributions in an implant-supported mandibular fixed partial denture (FPD) and surrounding bone, using 3-dimensional finite element analysis. MATERIAL AND METHODS: A 3-dimensional finite element model of a mandibular section of bone (Type 2) with missing second premolar and its superstructures were used in this study. A 1-piece 4.1 x 10-mm screw-shape ITI dental implant system (solid implant) was modeled for this study. Cobalt-Chromium (Wiron 99) was used as the crown framework material and porcelain was used for occlusal surface.The implant and its superstructure were simulated in a Pro/Engineer 2000i program. Total loads at 300 N were applied at the following locations: 1) tip of buccal cusp (300 N); 2) tip of buccal cusp (150 N) and distal fossa (150 N); or 3) tip of buccal cusp (100 N), distal fossa (100 N), and mesial fossa (100 N). RESULTS: The results demonstrated that vertical loading at 1 location resulted in high stress values within the bone and implant. Close stress levels were observed within the bone for loading at 2 locations and 3 locations; the former created the most extreme stresses and the latter the most even stresses within the bone. With loading at 2 or 3 locations, stresses were concentrated on the framework and occlusal surface of the FPD, and low stresses were distributed to the bone. CONCLUSION: For the loading conditions investigated, the optimal combination of vertical loading was found to be loading at 2 or 3 locations which decreased the stresses within the bone. In this situation, von Mises stresses were concentrated on the framework and occlusal surface of the FPD.     

Biomechanical rationale for intentionally inclined implants in the posterior mandible using 3D finite element analysis

PURPOSE: Since natural dental arches usually form Monson or Spee occlusal curvatures among the posterior teeth, they tend to incline in mesial and lingual directions. The purpose of this study was to examine the biomechanical rationale for placing implants according to these curvatures in the mandibular posterior region. MATERIALS AND METHODS: A 3-dimensional finite element model was created in which 2 implants were placed in the mandibular molar area. Stress distribution in the bone around the implants was analyzed under different distal implant inclinations. RESULTS: Stress in the cervical area of the mesial and distal implants and the surrounding bone was higher when the implants were placed parallel to each other compared to when the distal implant was placed with a mesial or mesiolingual inclination. DISCUSSION: The slightly smaller effect of a mesiolingual inclination compared to a mesial inclination can be explained by the large cantilever on the buccal side of the superstructure. CONCLUSION: Within the limitations of this study, it was suggested that there is a biomechanical rationale for placing implants in the posterior mandible area with a mesial inclination similar to that of natural teeth. It was also suggested that too much lingual inclination can put the implant at risk of overload.     

Evaluation of stress patterns produced by implant-retained overdentures and implant-retained fixed partial denture

The purposes of this study were to photoelastically measure the biomechanical behavior of 4 implants retaining different cantilevered bar mandibular overdenture designs and to compare a fixed partial denture (FPD). A photoelastic model of a human edentulous mandible was fabricated, which contained 4 screw-type implants (3.75 × 10 mm) embedded in the parasymphyseal area. An FPD and 3 overdenture designs with the following attachments were evaluated: 3 plastic Hader clips, 1 Hader clip with 2 posterior resilient cap attachments, and 3 ball/O-ring attachments. Vertical occlusal forces of 100 N were applied between the central incisor and unilaterally to the right and left second premolars and second molars. Stresses that developed in the supporting structure were monitored photoelastically and recorded photographically. The results showed that the anterior loading, the overdenture with 3 plastic Hader clips, displayed the largest stress concentration at the medium implant. With premolar loading, the FPD and overdenture with 3 plastic Hader clips displayed the highest stresses to the ipsilateral terminal implant. With molar loading, the overdenture with 3 ball/O-ring attachments displayed the most uniform stress distribution in the posterior edentulous ridge, with less overloading in the terminal implant. It was concluded that vertical forces applied to the bar-clip overdenture and FPD created immediate stress patterns of greater magnitude and concentration on the ipsilateral implants, whereas the ball/O-ring attachments transferred minimal stress to the implants. The increased cantilever in the FPD caused the highest stresses to the terminal implant.     

6颗种植体支持的上颌无牙颌固定义齿应力分布研究

目的:分析种植体位置变化时,6颗种植体支持的上颌无牙颌固定义齿的应力分布.方法:选择一名牙列缺失、牙槽骨中度吸收的志愿者,对其头颅部进行CBCT扫描,并利用一系列计算机软件进行数据转换,完成上颌骨三维实体模型的重建.设计8种不同位置种植体支持的固定义齿,建立8个三维有限元模型,分析种植体、上颌骨和固定义齿的应力分布情况.结果:远中没有悬臂的模型比有悬臂的模型的应力差值小;8种位点设计的模型都是应力集中在磨牙区种植体,种植体的应力集中点都是种植体颈部,且是偏向于颊侧.种植体的应力都是磨牙＞前磨牙＞前牙;在8种位点设计的模型中,种植固定义齿和颌骨位移都是集中在前牙区,种植固定义齿的位移是从前牙区向后牙区逐渐变小;8种模型的种植体应力都表现为以压应力为主.模型Ⅰ种植体(位点13、15、17、23、25、27)分散型排列,避免了远中悬臂的设计,6颗种植体的应力分布最均匀.结论:种植体植入位点于13、15、17、23、25、27,是8种方案中最佳的植入位点方案.     

Bone level change at implant-supported fixed partial dentures with and without cantilever extension after 5 years in function

OBJECTIVE: The aim of this study was to retrospectively analyze whether the inclusion of cantilever extensions increased the amount of marginal bone loss at free-standing, implant-supported, fixed partial dentures (FPDs) over a 5-year period of functional loading. MATERIAL AND METHODS: The patient material comprised 45 periodontally treated, partially dentate patients with a total of 50 free-standing FPDs supported by implants of the Astra Tech System. Following FPD placement (baseline) the patients were enrolled in an individually designed supportive care program. A set of criteria was collected at baseline to characterize the FPDs. The primary outcome variable was change in peri-implant bone level from the time of FPD placement to the 5-year follow-up examination. The comparison between FPDs with and without cantilevers was performed at three levels: FPD level, implant level, and surface level. Bivariate analysis was performed by the use of the Mann-Whitney U-test and stepwise regression analysis was utilized to evaluate the potential influence of confounding factors on the change in peri-implant bone level. RESULTS: The overall mean marginal bone loss for the implant-supported FPDs after 5 years in function was 0.4 mm (SD, 0.76). The bone level change at FPDs placed in the maxilla was significantly greater than that for FPDs in the mandible (0.6 versus 0.2 mm; p<0.05). No statistically significant differences were found with regard to peri-implant bone level change over the 5 years between FPDs with and without cantilevers at any of the levels of comparisons. The multivariate analysis revealed that the variables jaw of treatment and smoking had a significant influence on peri-implant bone level change on the FPD level, but not on the implant or surface levels. The model explained only 10% of the observed variance in the bone level change. CONCLUSION: The study failed to demonstrate that the presence of cantilever extensions in an FPD had an effect on peri-implant bone loss.     

Effects of mesiodistal inclination of implants on stress distribution in implant-supported fixed prostheses

PURPOSE: Patterns of von Mises stress values surrounding implants supporting fixed prostheses in the posterior edentulous maxilla were evaluated using 3-dimensional finite element analysis. MATERIALS AND METHODS: Implants were placed in maxillary bone in 2 different configurations. In the first configuration, implants were placed in the first premolar, second premolar, and second molar regions; in the second configuration, implants were placed in the second premolar and second molar regions, and a mesial cantilever was extended to the space of the first premolar tooth on the superstructure. On the implant placed in the socket of the second molar, 3 different inclinations were used (0, 15, and 30 degrees). Loading was applied in the vertical, oblique, and horizontal axes. RESULTS: Inclination of the implant in the molar region was found to result in increased stress. Significant increase in stress on the implant embedded in the premolar region was also seen in the design with the cantilever as compared to the conventional prosthesis design. Discussion: The stress concentrations observed at the neck of the implant were similar to results reported in the literature. CONCLUSION: The highest stress value obtained in the study was 194.2 MPa with oblique loading. This value did not exceed the endurance limit of pure titanium, which is 259.9 MPa.     

Stress analysis of effects of nonrigid connectors on fixed partial dentures with pier abutments

STATEMENT OF PROBLEM: In some patients, the pattern of missing teeth may require the use of a fixed partial denture (FPD) with an intermediate pier abutment. Information is needed regarding the biomechanical behavior and the position of a nonrigid connector for this treatment option. PURPOSE: The purpose of this study was to evaluate, by means of finite element method (FEM), the effects of rigid and nonrigid design types on stress distribution for 5-unit FPDs with pier abutments. MATERIAL AND METHODS: A 3-dimensional cross-section FEM model (SAP 2000) simulating a 5-unit metal ceramic FPD with a pier abutment with rigid or nonrigid designs (connector location at the mesial region of the second molar, at the distal region of the second premolar, at the mesial region of the second premolar, and at the distal region of the canine) was developed. In the model, the canine, second premolar, and second molar served as abutments. A supporting periodontal ligament and alveolar bone (cortical and trabecular) were modeled. A 50-N static vertical occlusal load was applied on the cusp of each abutment to calculate the stress distributions. Three different types of load were evaluated: loading of all cusps to simulate maximum centric occlusion contacts, loading of the canine to simulate a single anterior contact, and loading of the second molar to simulate a posterior contact. RESULTS: The analysis of the von Mises stress values revealed that maximum stress concentrations were located at the load areas for all models. Also, for all models, the highest stress values were located at connectors and cervical regions of abutment teeth, especially at the pier abutment. CONCLUSIONS: The area of maximum stress concentration at the pier abutment was decreased by the use of a nonrigid connector at the distal region of the second premolar.     

The cantilever fixed partial denture--a literature review.

The cantilever fixed partial denture (FPD) is a restoration with one or more abutments at one end and unsupported at the other end. Forces transmitted through the cantilevered pontics can cause tilting and rotational movements of the abutments. In a cross-arch unilateral cantilever FPD, the distal cantilevered unit is subjected to comparatively less force than the contralateral posterior abutment. The unilateral lack of terminal abutments causes lateral bending forces activate peripheral inhibitory feedback reactions from the periodontal and/or temporomandibular mechanoreceptors. The greatest strain in distal cantilevered FPDs is recorded mesial to the most distal retainer because most fractures occur in this location. To improve the prognosis of the FPD cantilever, the number of abutments should be increased and the number of pontics decreased. The abutment teeth need long roots and acceptable alveolar support. Prepared abutments require adequate length and parallel axial walls. An equilibrated and harmonious occlusion is necessary, as well as exemplary oral hygiene. A cantilevered FPD with adequate periodontal support can replace any tooth in the dental arch, but is especially useful as an alternative to a removable partial denture. The cantilevered FPD requires at least two abutment teeth. The only documented exception permitting a single abutment is the replacement of a maxillary lateral incisor with the canine as an abutment. An alternative to the cantilevered FPD is the osseointegrated implant. As osseointegrated implants become more popular, the need for the tooth-supported cantilevered FPD may decline, but it will remain an alternative treatment modality.     

无牙下颌固定种植义齿带末端悬臂的应力分析

目的:比较不同悬臂设计下颌种植支持全口义齿的骨及种植体应力分布特点,为临床种植修复提供生物力学分析依据。方法:建立3组下颌6个种植支持全口义齿的三维有限元模型,悬臂分别为3、6、9 mm。在悬臂末端垂直加载100 N的力。结果:种植全口义齿悬臂末端垂直加载时,末端种植体骨应力集中,易发生松动失败;末端种植体及中间种植体颈部应力集中,易发生植入体与基桩连接失败;连梁应力集中在与末端种植体连接处,此处易发生折断。悬臂长度增加骨应力、种植体应力及连梁应力明显增加。结论:悬臂越短越有利于力的均匀分布。6个种植体支持短悬臂修复设计较符合生物力学分布原理。     

Cantilever fixed prostheses utilizing dental implants: a 10-year retrospective analysis.

OBJECTIVE: The dental literature has been unclear about long-term success of fixed cantilever prostheses supported by dental implants. The disappointing results reported when cantilever fixed partial dentures (FPDs) are supported with natural teeth are not directly applicable to implant cantilever FPDs. This article reports on 10 years of implant-retained fixed prostheses primarily in the maxillary arch using the ITI dental implant system. METHOD AND MATERIALS: Sixty cantilever prostheses using 115 ITI dental implants on 36 patients were placed and monitored over a 10-year period. RESULTS: No implant fractures, abutment fractures, porcelain fractures, prosthesis fractures, soft tissue recession, or radiographic bone loss were recorded. All 60 cantilevered prostheses remain in satisfactory function. CONCLUSION: Positive, long-term results, using implant-retained cantilever FPDs can be achieved by: (1) using a rough surface implant of 4.1 mm or greater; (2) using an implant/abutment design that reduces stacked moving parts and reduces the implant-to-crowns ratio; and (3) using a cementable prosthesis design that eliminates the need for occlusal screw retention.     

Bone level alterations at implants placed in the posterior segments of the dentition: outcome of submerged/non-submerged healing. A 5-year multicenter, randomized, controlled clinical trial

Objective: To determine if longitudinal bone level change at Astra Tech^? implants placed in the posterior part of the dentition was influenced by the healing conditions provided following implant placement, i.e., submerged or non‐submerged healing. Material and methods: Eighty‐four patients and 115 fixed partial dentures (FPDs or cases) entered the study. The cases were randomized into two implant installation groups: initially non‐submerged (group A) or initially submerged (group B) implants. Three hundred and twenty‐four implants were installed (group A=153; group B=171): 145 in the maxilla and 179 in the mandible. Radiographs from the implant sites were obtained at FPD insertion (baseline) and subsequently every 12 months. In the radiographs, the position of the marginal bone at the mesial and distal aspects of the implants was determined and the radiographic (Rx) bone level change over time was calculated. Results: Seven implants failed to integrate (four in group A and three in group B). During the 5 years of monitoring, three implants had to be removed and 35 implants were lost to follow‐up. The Rx bone level alteration that occurred during year 1 was 0.02±0.38 mm in group A and 0.17±0.51 mm in group B. During the subsequent 4 years there was some further Rx bone loss in group B (0.02±0.62 mm), while in group A there was some gain of bone (0.07±0.5 mm). Conclusion: The peri‐implant bone level change and number of biological complications that took place during the 5 years was small and unrelated to the surgical protocol used for implant placement.     

A five-year life-table analysis on wide neck ITI implants with prosthetic evaluation and radiographic analysis: results from a private practice

This paper reports a 5-year life-table analysis on wide neck (WN) ITI implants placed in a private practice. In 212 patients, 263 implants were placed in the posterior region; 97% rehabilitated the molar area. Implants in the mandible and in the maxilla were 61.2% and 38.8%, respectively; the mean implant length was 9.7 and 8.9 mm, respectively. Eighty-nine percent sites had both vestibular and buccal bone lamellae > or =1 mm, 9.1% had one of them <1 mm and 1.9% had both lamellae <1 mm. Sinus perforation during surgery occurred in 52% of the maxillary implants. Prosthetic information was available for 249 implants; implants were involved in 157 single crowns (SC) and 80 fixed partial dentures (FPD). Radiographic analysis was performed on 102 implants that reached the 2-year control, and crestal bone loss (CBL) was measured. Results showed that five implants failed; the 5-year cumulative survival rate was 97.89%. The 1-year survival rate based on 259 implants was 98.8% and the 2-year survival rate based on 174 implants was 97.7%. In this 5-year timeframe, 94.3% of the SCs and 96.2% of the FPDs were free of complication. The mean CBL at the mesial and distal sides was 0.71 and 0.60 mm, respectively; bone losses >1 and >2 mm were recorded for 29.7% and 2.5% of the sides, respectively. This mid-term study showed that the WN ITI implants were highly predictable in private practice and that prosthetic complication in the molar area was an infrequent event.     

Peri-implant bone loss: management of a patient

This clinical report presents the prosthodontic management of early peri-implant bone loss in a partially edentulous patient. Two narrow Br?nemark implants (3.3 mm in diameter) were placed to retain a mandibular implant prosthesis in the area of the mandibular left second premolar and first molar. Two weeks after the prosthesis was put into function, the distal implant exhibited soft tissue reactions. Radiographically, bone corresponding to 4 threads and 7 threads was lost at the mesial and distal sites, respectively. After occlusal load reduction was made to the existing prosthesis, bone was observed to have regenerated sufficiently to restore the defect radiographically, though not to the original level. The bone remained at a similar level at 36 months after treatment.     

Analysis of stress on a fixed partial denture with a blade-vent implant abutment.

Using a two-dimensional finite element method, a study was made that compared the behavior of a model mandibular posterior fixed partial denture constructed on the second premolar abutment and a blade-vent implant imbedded at the site of the second molar with the behavior of a fixed partial denture constructed on the second premolar and second molar abutments. The following were the results: 1. Deflections of the implant fixed partial denture were less than those of the natural tooth fixed partial denture in vertical and inclined loads. 2. Stress concentration was markedly found in the pontic and the mesial and distal parts of the premolar retainer in both restorations and the implant neck in the implant fixed partial denture. 3. In the implant fixed partial denture, stresses induced in the surrounding bone became higher around the posterior abutment and became lower around the premolar retainer than the stresses produced with the natural tooth fixed partial denture. 4. Therefore it was suggested that, to relieve stress to the surrounding bone around the implant abutment, occlusal forces loaded to the implant fixed partial denture have to be more concentrated on the premolar abutment than do forces loaded to the natural tooth fixed partial denture.     

末端种植体倾斜状况的应力研究——向舌侧倾斜

目的：研究下颌种植体舌倾斜时末端种植体应力分布情况。方法：下颌５个种植体，除左侧末端种植体舌倾斜１５°外余为垂直状态。以１００Ｎ分别垂直加载于距末端种植体０、１０、２０ｍｍ的悬臂梁上，在微机上用ＳＡＰ８４软件分析种植体周围应力分布。结果：加载于距末端种植体２０ｍｍ时其种植周围应力均比加载于悬臂梁０、１０ｍｍ时为大。种植体舌侧倾斜时，在近中和舌侧骨界面应力亦较远中和颊侧骨界面的应力大。结论：种植义齿设计时应考虑种植体舌侧倾斜时骨界面舌侧和近中应力状况