后牙咬合对前牙修复的影响

后牙咬合对前牙修复的影响 The Influence of Posterior Occlusion When Restoring Anterior Teeth 后牙咬合对前牙修复的影响 abstract When any type of esthetic restorative procedure is being considered or performed, a comprehensive diagnosis and treatment plan is required. Attention to the diagnostic signs of the loss of posterior support (LPS) and their influence on the anterior dentition will guarantee a more predictable outcome. Historical solutions and their inadequacies are addressed. Patient presentations are utilized to demonstrate contemporary treatment of patients requiring esthetic rehabilitations who are lacking posterior support. 摘要:当任何一种美容修复计划被制订或是执行的时候，一个全面的诊断和治疗计划是必须的。 在修复过程中，对后牙支持丧失的体征和其对前牙牙列产生的影响加以考虑，将确保产生一个可 以预见的结果。从前治疗方法及其不足在这里被提出。这里我们利用的病例耐心地向大家展示了 对后牙支持丧失但需要美观重建的患者进行治疗的最新的治疗方法。 there is a general consensus that tooth retention amongst the aging population pays credence to preventive dentistry and patient education. Appearance is a common concern for this group of patients. A comprehensive examination allows the clinician to diagnose risk factors that are responsible for the deterioration of oral health and function. These patients often request restorative treatment with indirect restorations to enhance their appearance(figure 1). During the diagnostic phase,critical elements of posterior occlusion are overlooked at the expense of longevity of the proposed treatment (figures 2 and 3). Health, function, and esthetics should be the ultimate aim of any medical or dental comprehensive treatment plan. 在关注预防口腔医学和老年教育的老年人中对保留牙齿的态度是一致的。这些患者中对美观都很 重视。全面的检查将使临床医生能够对会引起口腔健康和功能造成损害的原因作出诊断。这些患 者常会要求用间接修复体进行修复以加强他们的美观。在诊断阶段，后牙咬合关系的因素常会被 忽略将导致修复体不能被长期使用。健康，功能和美观都应是牙科综合治疗计划的最终目的。 figure 1. Maxillary anterior teeth restored with porcelain laminate veneers for patient with adequate posterior support and occlusal stability. 图1.后牙有良好的支撑和咬合稳定的患者通过瓷贴面修复的上颌前牙. figure 2a. Maxillary anterior teeth previously restored but failed due to posterior bite collapse. 图2a,因为后牙咬合崩溃所致上前牙修复失败 figure 2b. Posterior support needs to be established before anterior teeth are restored. 图2b,在前牙修复之前,后牙咬合支持需要被建立. figure 2c. Cardinal signs for LPS are present clinically 图2C,后牙支持丧失的主要临床症状 figure 2d. Cardinal signs for LPS are present radiographically. 在放射检查中显示的后牙支持丧失的主要症状 figure 3a. Patient presented with LPS.后牙支撑丧失的患者 figure 3b. Mucosal-supported RPD failed to provide posterior support.粘膜支持的可摘局部义齿不能提供足够的后牙支持 figure 3c. Cardinal signs of LPS are present.后牙支撑丧失的主要体征 Diagnosis诊断 Diagnosis and treatment planning cannot be based on esthetic desires alone. A number of factors need to be evaluated prior to decision making:诊断和治疗计划不能仅以美观为基础。在 作结论之前，许多因素都应该被考虑。 1.Occlusal stability 咬合的稳定性 2.Status of periodontal and dental disease 牙周和牙齿疾病的情况 3. Anatomical limitations 解剖的限制 4.Space management 空间的管理。 Posterior support is an important factor to consider in order to achieve occlusal stability. The loss of posterior support is defined as the loss of occluding vertical dimension as a result of the loss or drifting of posterior teeth. Secondary occlusal trauma has been defined as the effects induced by occlusal force (normal or abnormal) acting on teeth with decreased periodontal support. Hence, it is possible for a patient with an almost intact dentition, but with a reduced periodontium to present with the signs of LPS (figure 4). 为提高咬合的稳定性，后牙的支持是一个必须要考虑的重要因素。丧失的后牙支持一般定义为因 为后牙缺失或是移位而导致咬合垂直距离的丧失。其次，咬合创伤也被定义为因为咬合力(正常 的或是不正常的)作用于牙周支持丧失的牙上引起的。因此对于拥有完整牙列的患者，但也会因 为不良的牙周情况而出现后牙支持丧失的症状 figure 4. Radiographs of patient with almost intact dentition but with reduced periodontium with the signs of LPS. 牙列较完整但牙周状况较差的并带有后牙支撑丧失的患者的放射影像 Clinically, such a diagnosis is based upon five cardinal signs (figures 2 and 3): 1. PDL widening 2. Fremitus 3. Fractured restorations 4. Drifting 5.Excessive wear 临床上，这种诊断主要是基于五个主要的体征。 1。牙周韧带增宽 2。震颤 3。修复或充填物断裂 4。漂移 5。过度磨耗 Treatment Solutions for the Loss of Posterior Support 对后牙支持丧失的治疗方法 Solutions for the treatment of patients presenting with the clinical signs of the loss of posterior support include: 对伴后后牙支持丧失患者体征的患者进行治疗的方法主要有 1. Removable partial dentures (RPD)可摘局部义齿 2. Cross-arch splinting跨弓夹板疗法 3. Implant-supported restorations种植支持式修复体 Removable Partial Dentures可摘局部义齿 There remains a group of patients that for medical, psychological, and financial reasons are poor candidates for fixed prosthodontics. These patients can be restored to function with the use of RPDs. Patient selection and the correct diagnosis are critical when deciding if treatment with removable prosthesis is appropriate. When treating a patient who exhibits the cardinal signs of LPS, a tooth or implant (supported and/or retained) RPD can provide additional support. With appropriate diagnosis and case selection these types of RPDs can satisfy the patient’s functional needs. 有一些患者因为医疗，心理或是经济的原因不会选择固定义齿修复。这些患者可以通过可摘局部 义齿来恢复其功能。当确定是否使用可摘局部义齿修复时，耐心地选择和正确地诊断很关键。当 治疗一个有后牙支持丧失体征的患者时，基牙或是种植体(支持或是固位)的可摘局部义齿能提 供辅助的支持。经过适当的诊断和病例选择这种类型的可摘局部义齿能够满足患者的功能要求。 However, there remains a group of patients who do not have an adequate number of posterior teeth or implants for a tooth-/implant-supported, or retained RPD. For this group of patients, tooth replacement with a mucosal supported RPD may not have any functional benefits and posterior support will not be re-established, leading to further demise of the dentition. 然而，也有一些患者并不具备足够数目的基牙或是种植体为可摘局部义齿提供基牙或种植支持或 固位。对于这些患者，用粘膜支持的可摘局部义齿来代替天然牙不可能为患者提供满意的功能和 恢复后牙的支持。将导致牙列情况的进一步变坏。 Restoring posterior support with mucosal-supported RPDs is controversial from a mechanical and periodontal view point. Whilst under load, the mucosa moves millimeters while natural teeth only move a mere 25-50 microns. This is based on the concept of differential movement of the mucosal tissues (millimeters) and the teeth (25-50 microns). These biomechanical issues compounded with patient compliance (25 percent of denture wearers never use their dentures) make it harder for a mucosal-supported RPD to provide adequate posterior support5 (figure 3). Prospective controlled studies have also shown that the oral function of subjects with a shortened dental arch (SDA) did not differ compared to subjects who have a SDA and were wearing a RPD.6-8 从机械和牙周的角度考虑，用粘膜支持的可摘局部义齿来恢复后牙的支持是有争议的。当经受咬 合的时候，粘膜会变形几毫米，而天然牙仅会移动25-50微米。这种争议正是基于这种理论。 这种生物力学的原理加之患者的顺应性(有25%的患者不会使用他们的义齿)使这种义齿很难 提供足够的后牙支持。前瞻性的对照研究明短牙弓的受试者和缺牙弓但使用可摘局部义齿的受 试者相比口腔功能没有显著的差异。 Therefore, a distal extension RPD did not appear to provide the patient with any additional posterior support or occlusal stability. Another survey of 77 patients with RPDs, reported social and oral function at levels compared to those with no dentures.9 There appears to be little need to replace lost posterior teeth with dentures until the person has fewer than three posterior functional units. The authors could not detect a lasting benefit from RPD wear. 因此一个远中游离游离缺失的可摘局部义齿不会给患者提供足够的后牙支撑和咬合稳定。另一个 对77个使用可摘局部义齿的患者进行的调查了和不使用义齿的患者相比他们的社交和口腔 功能的水平。结果表明除非患者少于三个后牙功能单位没有必要对其进行修复。这位作者不能从 使用可摘局部义齿的患者中找到使用义齿的好处。 The functional benefits of RPDs remain controversial as definitive controlled clinical trials have yet to be performed. However, based on current data and a logical approach to diagnosis and treatment planning, one should employ more caution when opting to restore a patient who exhibits LPS with a RPD. 在作最终的对照临床实验完成之前，可摘局部义齿使用的好处仍是有争议的。然而，基于目前的 数据和对诊断和治疗计划的理论推理，医生在对后牙支持丧失的患者进行可摘局部义齿修复时应 谨慎一些。 Effect of RPD on Periodontal Status 可摘局部义齿对牙周状况的影响 Many studies have looked at the effect of RPDs on dental and periodontal structures.10,11 Some have concluded that with a high level of periodontal maintenance and oral hygiene RPDs do not result in periodontal disease.10 However, there is evidence to the contrary. In one controlled in-vivo study of 99 patients, it was found that“There was a strong correlation between the presence of local pathological alterations accompanying the use of RPDs and poor oral hygiene.”11 许多研究都关注于可摘局部义齿对牙齿和牙周状况的影响。一些研究表明高水平的牙周维护和保 持口腔卫生状况的情况下，可摘局部义齿的使用不会引起牙周疾病。然而也有相反的证据。一例 对99个患者的体内对照实验表明，在口内病理变化和可摘局部义齿使用及较差的口腔卫生状况 间有很强的相关性。 Eighteen to 25 percent of RPD abutments were “loose” and periodontal inflammation was associated with 68 percent of all abutments. In another 10-year study, survival rates of teeth adjacent to treated and untreated posterior bounded edentulous spaces, it was found that survival of teeth adjacent to a single posterior edentulous space was negatively associated with RPD placement compared with no treatment.12 If the patient with a mucosal-supported RPD is unable to maintain an adequate level of oral hygiene, further tooth loss is more likely. Losing more teeth will worsen the problem associated with LPS.约18%到25%的可摘局部义齿的基牙 会出现松动，并且牙周炎症会见于68%的基牙。在另一个10年的，关于缺牙间隙两侧治疗及未 治疗的基牙的保存率的研究中，实验表明，与不用可摘局部义齿修复的患者相比，经过可摘局部 义齿修复的邻近后牙缺隙的基牙的保存率与可摘局部义齿的使用负相关。如果一个患者使用一个 粘膜支持的可摘局部义齿，且不能保持一个良好的口腔卫生状况，进一步的牙齿缺失是可能的。 缺失更多的牙齿将使与后牙支持丧失相关的问题加重。 RPDs functional benefits remain controversial as definitive-controlled clinical trials have yet to be performed. The ability to draw consensus on the benefits and impacts based on currently available data may be premature. The majority of evidence is from correlational, poorly controlled studies with biased or select samples. However, current data should not be disregarded as it does provide some useful information in relation to clinical outcomes and trends. 在最终的对照临床实验结果作出前，可摘局部义齿的优点目前仍有争议。基于目前的数据得出关 于好处和影响的达成一致是不成熟的。大多数基于对病例对照实验得出的相关性结果都存在偏倚 或是选择样本误差。但目前的数据也不能不考虑，因为他毕竟为临床的工作提供了一些有用的信 息和临床的结果的趋势。 Cross-arch Splinting跨弓夹板 Cross-arch splinting has also been used to treat patients diagnosed with LPS. Adequate oral hygiene, and sufficient number of abutment teeth are essential to the success of such treatment modalities13 (figure 5). The patient in figure 5 received a periodontal prosthesis more than 20 years ago. This should be considered a successful restoration.However, had failure occurred a short period after delivery of the definitive restorations, the consequences may have been catastrophic. As every tooth is joined together in a single prosthesis, a localized problem may deem the restoration or a large part of it nonfunctional, requiring replacement. The risk-to-benefit ratio for these restorations is unfavorable.14 It has been said that “for every advantage splinting has to offer there is at least one disadvantage that must be accepted.” 跨弓夹板也曾被用于治疗诊断为后牙支持丧失的患者。在这种治疗中，充分的口腔卫生控制和足 够数目的基牙是必须的。图5中的患者接受牙周修复超过了20年，这例被认为是一例成功的治 疗。然而如果应用最终修复体后失败发生，那么结局应是灾难性的。因为每个牙齿都被连成一个 整体，一个局部的问题将会引起整个修复体功能丧失，以致于需要替换。这种修复体的风险和好 处的比例也是不利的。据说:每一项夹板的优点都会有一个相应的缺点与之对应。 figure 6 demonstrates how the failed prosthesis in figure 5 was remade with the use of dental implants for support. “New sophisticated techniques are available, but the concept of a correct diagnosis, identifying the etiological factors, formulating a treatment plan and developing a logical sequence of therapy hold true today as they did five decades ago.”16 图6提示了图5中失败的病例如何通过口腔种植来获得支持。“新的成熟的技术可以被获得，然 而和50年以前一样，正确的诊断，准确地判断病因，制定治疗计划，并确定合理的治疗顺序依 然十分重要。 figure 5a. Radiographs of maxillary reconstruction with cross-arch stabilization at 20 years. 利用跨弓夹板进行上颌修复重建20年的患者的放射影像 figure 5b. Occlusal view of maxillary reconstruction with chipped ceramics, dental caries, and fractured connector necessitating replacement of prosthesis at 20 years上颌利用瓷贴面进行的 修复重建咬合面观.经过20年后发生的龋坏及连接体断裂迫使必须重新修复. 6a. Radiographs of patient in Figure 5 after maxillary reconstruction with dental implant supported restorations图5中的患者利用口腔种植体进行重新修复后的放射影像 figure 6b. Right lateral view of maxillary implant-supported restorations.右侧观 figure 6c. Left lateral view of maxillary implantsupported restorations.左侧观 Implant-supported Restorations 种植支持式修复体 The use of osseointegrated dental implants have defied many of the empirical guidelines previously accepted.The survival of cantilevered restorations supported by four to five short dental implants in the symphisis of the mandible is well documented.18,19 These complete mandibular prostheses, which replace 12 to 14 teeth, with up to 10-15 mm posterior cantilevers clearly defy the empirical rules that have been religiously followed in clinical dentistry (figure 7). A new era in clinical dentistry has arrived. Two patients are selected to demonstrate the contemporary treatment of the loss of posterior support. 骨性结合的口腔种植体的使用已经以许多从前的治疗原则提出挑战。用4到5个种植体作为支 撑的悬臂梁式的下颌修复体的存活率很高。这些下颌修复体可以代替12到14个天然牙，长达 10到15mm的后牙悬臂梁对从前口腔临床工作中获得的经验提出挑战。临床牙科的新时期已经 来临。有二例患者已经被选中用现代的治疗方法进行后牙支持丧失的治疗。 The patient in figures 4 and 8 presented with the cardinal signs for LPS. In order to establish posterior support the treatment plan for this patient consisted of: 图4到图8 中的患者带有后牙支持丧失的主要体征。为了使患者恢复后牙支持主要的治疗方法 有: 1. The removal of the teeth with poor or nonmaintainable prognosis14; 2. Bilateral sinus lifts20; and 3. Replacement of missing teeth with implant-supported restorations. 1。去除那些预后不良或没有保留价值的牙齿。 2。双侧上颌窦提升 3。利用种植支持式义齿代替缺失的牙齿。 After removal of the maxillary teeth and prior to dental implant placement, an immediately loaded provisional prosthesis was delivered to restore the dentition and establish posterior support. Three transitional dental implants were used as abutments for the immediately loaded prosthesis in order to establish posterior support (figure 9). The patient was stabilized in terms of disease control, occlusion, function, phonetics, and esthetics. The immediately loaded transitional dental implants were removed once the definitive dental implants were osseointegrated and loaded. The additional step of providing the patient with a transitional implant-supported provisional restoration ensured patient comfort during the osseointegration period while minimizing the risk of uncontrolled loading and micromotion of the definitive dental implants.21在拔除上颌牙齿之后，和进行种植修复之前，一个即刻的义齿被制作以为患 者恢复牙列的功能及获得后牙支撑。三个过渡性的口腔种植体被用来作为这个即刻修复体的基牙 以建立后牙的支撑。患者在口腔疾病，咬合，功能，发音和美观等方面都比较稳定。当最终的口 腔种植体达到骨性愈合和稳定后，即刻的义齿可以被去除。这种种植支持的过渡性义齿的应用使 患者在种植体骨性愈合阶断能够获得足够的舒适，并减少了不可控制的负荷，和最终种植体的微 运动。 figure 7a. Photo of mandibular hybrid prosthesis supported by five short dental implants and cantilevered.五个短的口腔种植体支持的下颌单臂梁式修复体图片 figures 7b. Radiograph of mandibular hybrid prosthesis. 放射影像 figure 8. Preoperative photo of patient. Cardinal signs of LPS are present with an almost intact dentition. Generalized periodontal attachment loss is the cause of LPS.患者的术前照片.虽然没 有牙列缺损,但牙周病变是引起后牙支撑丧失的原因. figure 9a. Three transitional dental implants are used to provide posterior support and function.三个过渡性口腔种植体被使用 figure 9b. Intaglio surface of maxillary immediately loaded provisional restoration. 临时义齿的组织面 figure 9c. Occlusal view showing copings on transitional dental implants indexed to maxillary provisional restoration with acrylic resin. 从咬合面观看临时种植体上的根帽被用树脂粘在了过渡性义齿上 figure 9d. Satisfactory esthetics achieved with the implant-supported and immediately loaded provisional restoration. 过渡义齿的外观较满意 Once osseointegration of definitive dental implants had been established, indirect provisional restorations were fabricated to maintain posterior support. The provisional restorations (figure 10) allowed objective evaluation of occlusal stability, phonetics, and esthetics prior to the fabrication of the definitive restorations22 (figure 11). Comparison of the photos in figures 10 and 11 demonstrates how the treatment objectives that were established and tested with the provisional restorations were duplicated in the definitive restorations. Posterior support had been established with the aid of implant-supported restorations. 一旦最终口腔种植树体的骨性愈合完成，间接的过渡性修复体被制作以保持后牙的支持。这种过 渡性修复体使我们在最终修复体完成之前能够对咬合稳定性，发音，和美观作出评估。比较图 10和图11提示治疗目的是如何实现的，及如何在最终修复体制作中复制过渡性修复体。后牙支 撑通过种植支持式修复体得以恢复。 figure 10a. Right lateral view of definitive implant-supported provisional restorations. 最终修复体的右面观 figure 10b. Left lateral view of definitive implant-supported provisional restorations. 左面观 The patient in figure 12 presented with pathological loss of tooth structure, which resulted in posterior bite collapse and loss of vertical dimension of occlusion.3,23-25 Radiographs clearly show the extent of damage to the dentition (figure 12). Many teeth had also been affected by pathological tooth surface loss associated with attrition and erosion.23 Signs of both diurnal and nocturnal bruxism were clearly visible on presentation. The proximity of the chin to nose distance and the presence of angular folds and angular cheilitis confirmed the diagnosis of the loss of vertical dimension of occlusion (figure 13).图12中的患者是因为病理性地牙体结构丧失， 导致后牙咬合崩溃，以致于垂直距离降低。放射检查提示了牙列的广泛的损坏。许多牙齿也因为 牙齿表面的磨损及腐蚀而病理性缺损。白天或是晚上的磨牙症的症状也可以看到。下颌前点到鼻 的距离降低及口角皱纹及口角炎的发生都提示了垂直距离的降低。 figure 12a. Radiographs of a patient with a severely compromised dentition on presentation. 严重牙列缺损的患者的放射影像 figure 12b. Intraoral photograph of patient in Figure 12a. 图12中患者的口内像 figure 13. Patient presented with persistent angular folds and cheilitis relating to loss of vertical dimension of occlusion. 患者呈现垂直距离降低的症状,口角炎.和口角皱纹加深 figure 14. Provisional restorations. The mandibular arch with immediately loaded prosthesis at two weeks. 临时修复体.种植后2星期用过渡性义齿修复 In order to re-establish posterior support for this patient, it was decided to restore the maxillary teeth with tooth-supported cast restorations, and the mandibular teeth with implantsupported restorations. The provisional restorations allowed objective evaluation of occlusal stability, phonetics, and esthetics prior to the fabrication of the definitive restorations.22 The decision to immediately load the mandibular arch for this patient was based on a combination of factors (figure 14). 为了重建患者后牙的支撑，决定在患者上颌用天然牙支持的铸造修复体来修复。而在下颌采用种 植体支持的修复体。过渡性的修复体使在最终修复体完成之前可以客观地对患者咬合稳定性，发 音和美观等方面进行评估。这种即刻加载的方法是基于对患者多方面因素的考虑。 Firstly, success with immediate loading of the mandible is well documented.26,27Secondly, patients wearing complete mandibular dentures opposing a fixed prosthesis in the maxilla tend to have poor acceptance of treatment.Thirdly, the provision of a fixed prosthesis in the mandible for this patient will immediately overcome the two major diagnostic findings for this patient. Posterior support and vertical dimension were both re-established with immediate effect. The osseointegration period may coincide with the testing of form, function, phonetics, and esthetics with the provisional restorations.22 The patient was stabilized in terms of disease control, occlusion, function, phonetics, and esthetics. 首先对下颌进行即刻加载是有文献依据的。其次患者使用一个下颌全口义齿对应一个上颌的固定 修复体是让患者难以接受的修复方法。再者为患者在下颌提供一个固定的修复体可以立刻解决在 诊断中发现的两个主要的问题。后牙支撑和垂直距离立即被恢复了。在骨结合阶段可以通过对过 渡性义齿的功能，发音，和美观进行检验以发现问题。并使患者逐渐适应。患者在疾病控制及咬 合，功能，发音及美观等方面获得稳定。 After the process of osseointegration definitive restorations were fabricated. Fullmouth radiographs confirmed optimum oral health and anatomic harmony (figure 15). figure 15 demonstrates how occlusal stability and functional harmony were re-established for this patient. Adequate esthetics was achieved in a controlled, objective, and predictable fashion (figure 16). A hard occlusal guard was delivered to protect the restorations from excessive forces created during diurnal and nocturnal bruxism.28 当最终种植体的骨性结合完成以后，全口的放射检查以确定口腔健康及解剖结构的协调。图15 显示了在这个患者建立了咬合的稳定及功能的协调。可以通过可控制的，客观的，可预期的方法 来实现充分的美观。一个坚硬的咬合保护器被子用来保护修复体不受白天或是夜间磨牙习惯的影 响。 figure 15. Full-mouth radiographs and photograph of definitive restorations.最终修复体的全口 放射影像 figure 16. Patient smiling with definitive restorations.[/color][color=blue]患者用最终修复体照 片 Discussion 讨论 LPS is a true disease that is most often overlooked. The diagnosis of such disease is defined with cardinal clinical signs and symptoms. Although there is a new tool in our armamentarium (dental implants), the principles of diagnosis and treatment planning remain the same. The treatment for LPS is still controversial and a comprehensive treatment should include detailed occlusal and periodontal diagnosis in order to ensure the longevity of the restorations. Adequate posterior support should be one of the requirements for long-lasting anterior restorations. Historically, a common misconception has been related to the deleterious effects of the loss of posterior teeth on the remaining dentition and health.29 A common belief was that 80 medical and dental abnormalities would result from the loss of posterior teeth.29 The belief that missing teeth result in arch collapse and the loss of arch integrity is also evident in more recent dental literature.30-32 In fact,it is apparent that missing posterior teethdo not necessarily result in LPS or the loss of occlusal integrity.33 It is unnecessary to replace all missing posterior teeth to avoid problems associated with LPS.34 The efficacy of a shortened dental arch has been confirmed.35 A shortened dental arch has been defined as a dentition with a reduction of occlusal units (pairs of occluding premolars and molars) starting posteriorly. 35 The prevalence of the shortened dental arch has been estimated at 25 percent for 41- to 45-year olds and 70 percent for 61- to 65-year olds.36 The question about the function, occlusal integrity, adaptive capacity, and esthetics in relation to the latter group has been addressed and answered. It appears that functional demands can be met even with some loss of molar support.37 后牙支撑丧失是一种常常被忽视的疾病。这种疾病的诊断主要是依靠临床体征和症状。虽然我们 现在有了新的设备，但是这种疾病的诊断和治疗仍没有太大的变化。对后牙支撑丧失的治疗仍是 有争议的，但是全面的治疗必须包括对咬合及牙周情况的精细地诊断以保证修复体使用的长期 性。充分的后牙支撑是保证前牙修复成功的先决条件。长期以来，人们一直误以为缺失的后牙对 尚存的牙列产生很坏的影响。一种大众的观点是，80%的医疗的和口腔病损是因为后牙缺失引 起的。在最新的牙科文献中，也提出缺失的牙齿会导致牙弓缺损及牙列完整性的破坏。事实上， 很明显缺失的后牙不一定会导致后牙支撑丧失。或咬合稳定性的丧失。不是一定要修复所有缺失 的后牙以预防后牙支撑丧失问题的发生。短牙弓的有效性已经被证实。短牙弓被定义为后牙咬合 单位的减少。对于41到45岁的患者短牙弓的发生率约为25%，而对于61到65岁的患者，其 发生率约为70%。对于后一群人，关于功能，咬合完整性，适应能力和美学的问题已经被提出 和解释。似乎对于一些磨牙支撑丧失的患者功能的要求依然能够满足。 Epidemiological studies show a lack of correlation between the loss of molar support and impaired oral function.38 There is sufficient adaptive capacity to ensure acceptable oral function in the shortened dental arch when premolar teeth are present.38 The SDA can provide long-term occlusal stability.6-8 Esthetics does not seem to be adversely affected by missing posterior teeth either. In a survey of patients with a shortened dental arch it was evident that these patients rate their appearance as acceptable.37流行病学研究表明在磨牙支撑丧失和口腔 功能损害之前缺乏相关性。当前磨牙存在的情况下，有足够的适应能力以保证可接受的口腔功能。 短牙弓可提供较好的咬合稳定性。美观也不会被后牙的缺失所影响。在一项对短牙弓患者的调查 中发现患者认为自己的外观是可以接受的。 The decision to intervene when a patient is missing posterior teeth should be based on a comprehensive diagnosis and treatment plan. The main diagnostic findings of LPS must be established before any intervention and treatment. The combination of existing periodontal involvement and increased occlusal loading, such as in a reduced dentition, appear to be potential risk factors for further loss of teeth.39当决定对缺失后牙的患者进行治疗时，必须进 行全面的诊断，并制订完善的治疗计划。在治疗和干预前要对后牙支撑丧失作出明确诊断。综合 考虑存在的牙周状况和增加的咬合力。例如减少的牙弓。似乎是导致进一步缺牙的潜在因素。 Conclusion and Clinical Significance When any type of esthetic restorative procedure is being considered or performed, a comprehensive diagnosis and treatment plan is required. This should include a close analysis of the total stomatognathic system with particular attention to posterior support. 结论和临床意义。 当任何一种美观修复治疗计划被制定和执行时。一个全面的诊断和治疗计划是必须的。这将包括 对全部口颌系统的全面分析和后牙支撑的特别注意。