Occlusion in implants: problems in clinical cases

On prosthodontic treatment with dental implants ,we have refered to crown restorations similar to natural teeth and recostructed so far. Therefore differences between implants and teeth have happened many problems. Especially, for we harmonize occlusion for implant restoration with supporting tissue, superstructure of implant prosthesis, muscles surrounding the jaw and temporomandibular joint, how should we compensate for differences between implants and teeth, and observe occlusal shift and symptom in postoperative progress? It seems that there is little evidence on the relation between implant and occulusion. While, it is necessary for examination of the problem on occlusion for implant restoration to consider mechanically risk and character of dentition. It is essential to reveal that the cause of happened problems is whether trouble of implant or risk of dentition. There has not been the consensus between parafunction and practice in prothodontics in natural dentition yet. How do implants harmonize with nonfunctional and nonphysiological force? We cannot overlook problems that the factor of surplus force affects implant restorations. In the symposium, I propounded some problems through clinical cases.     

Occlusal considerations in implant therapy: clinical guidelines with biomechanical rationale

Due to lack of the periodontal ligament, osseointegrated implants, unlike natural teeth, react biomechanically in a different fashion to occlusal force. It is therefore believed that dental implants may be more prone to occlusal overloading, which is often regarded as one of the potential causes for peri-implant bone loss and failure of the implant/implant prosthesis. Overloading factors that may negatively influence on implant longevity include large cantilevers, parafunctions, improper occlusal designs, and premature contacts. Hence, it is important to control implant occlusion within physiologic limit and thus provide optimal implant load to ensure a long-term implant success. The purposes of this paper are to discuss the importance of implant occlusion for implant longevity and to provide clinical guidelines of optimal implant occlusion and possible solutions managing complications related to implant occlusion. It must be emphasized that currently there is no evidence-based, implant-specific concept of occlusion. Future studies in this area are needed to clarify the relationship between occlusion and implant success.     

Does evidence of implant occlusion exist?

This article reviews epidemiologic studies and basic researches concerning the mechanical risk factors that cause overload in implant occlusion. When natural teeth are adjacent to an implant, occlusal contact on the implant prosthesis requires a reduced initial mechanical load on the implant. This is called the implant-protected occlusion concept. However, few studies support this concept, and several researchers are concerned about the influence on the temporomandibular joint and the adjacent teeth when using this occlusal concept. It is thought that the same initial mechanical load on the implant and adjacent teeth does not result in an overload on the implant itself. The influence of a non-axial load, large cantilevers, and offset loading with a large occlusal table is greater than that of the axial load because of the bending moment. However, no epidemiologic study supports the biological influences of overloading. Meta-analysis of the connection of natural teeth and implants shows the biological and prosthetical risks.     

复杂修复的咬合设计理念及关键临床步骤

复杂修复由于涉及牙位多、对咬合关系影响大等一直是口腔修复的疑难之一。对这类修复临床问题的解决首先是建立正确的修复理念，文章对修复治疗中如何客观认识咬合与颞下颌关节紊乱病之间的关系进行了梳理，并对复杂修复中如何基于患者口颌系统的功能特点设计个性化咬合的临床步骤进行了阐述。     

Considerations for fabrication of implant-supported posterior restorations

Implant-supported posterior restorations must be fabricated following established prosthodontic principles. The need for screw-retained abutments and the narrow diameter of root-form implants dictate additional treatment protocols that fall beyond the scope of conventional prosthodontics. Cemented restorations offer simplicity and good control of morphology, but can only be considered if removal or no reservicing of the restoration is anticipated. Screw-retained restorations allow for reservicing or remediation but necessitate centering of the retaining screw within the occlusal anatomy. When the implant is misaligned, axis problems are solved with preangled copings, custom copings, or double frameworks. The diameter of root-form implants is significantly smaller than posterior natural teeth, and the emergence of the restorations must be progressively flared to achieve proper morphology. Limited interocclusal space and implant placement may dictate restoring posterior teeth as premolars, selecting a short abutment or a nonsegmented ("UCLA") abutment, or overlapping the crowns over the soft tissues. The final abutment selection is best assisted with a diagnostic waxing and with provisional restorations anticipating the completed treatment.     

Sensory responses from loading of implants: a pilot study

PURPOSE: Osseointegrated implants lack a periodontal ligament. Nevertheless, masticatory function in subjects with implant-supported restorations appears similar to function in those with natural dentition. It is not clear how the neurophysiologic mechanisms that modulate jaw movement are associated with osseointegrated implants. This study examined the output from the inferior alveolar nerve during implant loading. MATERIALS AND METHODS: In 3 dogs, 3 premolars were extracted in the mandible and 2 endosseous titanium implants were placed, allowed to osseointegrate for 3 months, and loaded with vibration force at the threshold response for tooth vibration, at 2x threshold, and at 3x threshold. Neurophysiologic recordings were made from the inferior alveolar nerve during loading of both implants and the adjacent molar and canine. The response magnitude in action potentials in the 50- ms poststimulus period and latency of inferior alveolar afferents in milliseconds were compared following implant loading. RESULTS: Detectable inferior alveolar nerve responses were recorded following loading from both the implants and the teeth at 2x and 3x threshold. However, the response magnitude of teeth (canine, 2.38 +/- 0.18 at 2x, 2.78 +/- 0.2 at 3x; molar, 2.2 +/- 0.16 at 2x, 2.5 +/- 0.21 at 3x) was twice that of the implants (anterior, 1.3 +/- 0.12 at 2x, 1.68 +/- 0.13 at 3x; posterior, 0.8 +/- 0.1 at 2x, 1.53 +/- 0.15 at 3x). The differences in response magnitude between the teeth and implants were significant (P < .05). The latency of response was similar. DISCUSSION: Management of the occlusion for implant-supported restorations has been empirically developed. An underlying assumption has been that implant-guided jaw function lacks significant proprioception to modulate mastication and related jaw movements. This animal study provides preliminary evidence that force application to implants does elicit a proprioceptive response. CONCLUSION: Loading of implants does elicit a sensory response that can be observed in the inferior alveolar nerve. The implications are that during occlusal function, information from regions associated with the implant can provide knowledge that could potentially modulate jaw activity in a manner similar to natural teeth.     

多数牙缺失重建探讨

多数牙缺失的患者一般都存在的垂直距离降低，余牙面磨损，无对颌牙的余牙伸长，丧失正常的牙尖交错位等问题。目前发达国家多采用固定修复的方法（含种植义齿）进行咬合重建。本文应用学理论，结合我国目前的条件，采用整铸基托及功能印模技术对多数牙缺失后进行咬合重建，目的是总结临床实践经验，探讨多数牙缺失重建的有关问题。     

无牙颌种植义齿的咬合设计

随着种植义齿的不断普及,种植义齿的咬合设计也引起了大家的关注。本文就无牙颌种植义齿咬合设计的一些相关方面,如应力改变与颌骨的关系,咬合设计与种植并发症,髁突的水平关系确定,尖牙引导牙合的设计,种植体与天然牙对牙合力反应的异同等进行探讨和分析。     

Guidelines on occlusion and articulation. Part 1. Overdentures on implants in the edentulous lower jaw

When loading dental implants it is generally accepted that one should minimize horizontal forces. This has its implications for the choice of the occlusal concept that is to be used for overdentures on implants. In this article various occlusal concepts for overdentures on dental implants in the lower jaw opposing different types of dental arch mutilation in the upper jaw are discussed. Apart from number, length and position of the implants, the condition of the opposite dental arch and the intermaxillary relationship play a role when choosing an occlusal concept. This article discusses the type of overdenture and the occlusal concepts for the edentulous lower jaw. A distinction is made between mucosally borne, mucosally-implant borne and implant borne overdentures on dental implants.     

种植修复中的牙合学问题

口腔种植修复技术的出现,为口腔修复提供了新的临床途径。种植修复中的咬合问题不仅对恢复美观及功能有着重要影响,还关乎种植的成败。在种植修复前需考虑天然牙与种植体存在的差异,并根据缺失牙范围、设定的修复体类型等对种植修复进行有针对性的咬合设计。本文旨在对种植义齿修复相关牙合学问题进行探讨。     

Evidence-based considerations for removable prosthodontic and dental implant occlusion: a literature review

The dental literature is filled with discussions of dental occlusion, occlusal schemes, philosophies, and methods to correct and restore the diseased, worn, or damaged occlusion. Traditionally, these discussions have been empirical in nature and not based on scientific evidence. Due to the empirical nature of the literature, the study of occlusion has been extremely complex and troublesome to both pre- and post-doctoral students. The introduction of osseointegrated implants has further complicated the situation. Dentists may apply the principles of occlusion for the natural dentition directly to implant-supported and retained restorations. Although this may be successful, this rationale may result in overly complex or simplified treatment protocols and outcomes. There is an emerging body of scientific literature related to dental implant therapy that may be useful in formulating treatment protocols and prosthesis designs for implant-supported restorations. This review focuses on some of the "classic" removable prosthodontic literature and the currently available scientific literature involving removable prosthodontic occlusion and dental implant occlusion. The authors reviewed the English peer-reviewed literature prior to 1996 in as comprehensive manner as possible, and material after 1996 was reviewed electronically using MEDLINE. Electronic searches of the literature were performed in MEDLINE using key words-animal studies, case series, clinical trials, cohort studies, complete denture occlusion, dental implant function, dental implant occlusion, dental implant occlusion research, dental implant functional loading, dental implants, dental occlusion, dental occlusion research, denture function, denture occlusion, dentures, implant function, implant functional loading, implant occlusion, occlusion, and removable partial denture occlusion-in various combinations to obtain potential references for review. A total of 5447 English language titles were obtained, many of which were duplicates due to multiple searches. Manual hand searching of the MEDLINE reference list was performed to identify any articles missed in the original search.     

Fabrication of a functionally generated, implant-retained fixed partial denture

Partially edentulous patients are frequently restored with implant-supported restorations between and opposing natural teeth. Differences in horizontal and vertical mobility of teeth and dental implants necessitate occlusal contact modification to create prostheses that harmonize with the opposing dentition. This article describes a functionally generated path technique to achieve optimal articulation between an implant-retained fixed partial denture and the patient's dentition.     

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口腔种植修复技术的出现,为口腔修复提供了新的临床途径。种植修复中的咬合问题不仅对恢复美观及功能有着重要影响,还关乎种植的成败。在种植修复前需考虑天然牙与种植体存在的差异,并根据缺失牙范围、设定的修复体类型等对种植修复进行有针对性的咬合设计。本文旨在对种植义齿修复相关学问题进行探讨。     

Orthodontics Using an Occlusal Splint: A Clinical Report

Careful management of the occlusion is necessary for successful prosthodontic treatment. A reorganized occlusal approach requires a more accurate registration of the desired jaw position, and where it is difficult to achieve this, an occlusal splint is indicated. This clinical report documents a 60‐year‐old man with a Prosthodontic Diagnostic Index Class IV dentition, who prior to a full‐mouth reconstruction, underwent occlusal splint therapy with a Michigan‐type splint that incorporated z‐springs to allow concurrent orthodontic tooth movement of two anterior teeth to positions that would allow favorable restorations by correcting occlusal and esthetic form.     

Management of the edentulous patient

Being edentulous is a handicap, and the main objective of implant placement is to provide support of fixed prostheses or to stabilize complete dentures in the edentulous jaw. Clinical experience and clinical studies have demonstrated the broad application of non-submerged ITI implants in prosthetic therapy in standard sites and in situations of advanced atrophy or substantial loss of tissue. The ITI implant was developed for universal use in partially and completely edentulous patients and for replacement of single missing teeth. The abutment system offers the choice of both removable and fixed prostheses with identical secondary parts. The present article describes the use of ITI implants for prosthodontic rehabilitation in the completely edentulous jaw. Indications and various types of fixed or removable prostheses, alternatives and variations of design are discussed. Prosthetic design is dependent on the number and location of implants, and conversely, the number of implants that can be placed will determine the choice of prosthesis. Treatment planning in general and with respect to individual anatomic-morphologic conditions is described for the upper and lower jaw. Details of clinical procedures with ITI implants related to the specific design of prostheses are presented. Biomechanical aspects of fixation and stabilization of prostheses and aspects of occlusion to be built up complete the overview.     

锥体束CT辅助种植义齿导航系统

目的:研发种植义齿导航系统。方法:通过制作缺失牙位模板义齿初步确定植体的定点和方向。再通过CBCT精确测量,利用模板定位仪精确定位,使植体在颌骨内达到理想定位。结果:统计测量70枚术后种植体,经CBCT冠切、矢切检验,达到理想定位标准者占98.6%。讨论:1、种植体在缺隙的定点和在颌骨内的定位应该符合牙合力传导的规律。植体在颌骨内的方向应与相应义齿牙合力传导方向一致。一般情况下,牙合力传导方向与该自然牙的牙体长轴方向一致。2、在部分病例中,植体在颌骨内的定位受到局部骨质条件的限制。植体的理想定位标准是:依据缺失牙位修复体的功能需求,充分利用缺失牙位局部骨质条件,结合种植体的系统、系列特点,依此确定植体的直径、长度以及植体在颌骨内的方向。3、本导航系统首先以自然牙的牙体长轴方向作为参照制作模板义齿,再以锥体束CT摄影技术进行检验,最后再用模板定位仪进行矫正,确保植体在颌骨内达到理想定位。结论:CBCT辅助种植义齿导航系统操作简便,费用低廉,效果良好,可以推广应用。     

Prosthodontic considerations designed to optimize outcomes for single-tooth implants. A review of the literature

Background: The aim of this study was to review the literature on the restoration of single‐tooth implants, and to develop evidence‐based conclusions to optimize aesthetic, biologic and patient‐related outcomes. Methods: An electronic and hand search was conducted using the search terms ‘dental implants, single‐tooth; dental restoration, temporary; dental impression materials; dental impression technique; dental prosthesis, implant‐supported; dental prosthesis design; dental abutments; dental occlusion; maintenance; survival; and survival analysis’. Resultant titles were screened, and full text was obtained where relevant. The authors selected the most appropriate articles, giving preference to systematic reviews and long‐term, patient‐based outcome data. Results: Thirty‐nine articles were selected and critiqued by the authors. Conclusions: There was strong suggestion by several authors that peri‐implant soft tissue aesthetics can be sculpted through provisional restoration contour, but there are no clinical outcome studies to define or support this claim. Laboratory studies demonstrate that pick‐up type impression copings in conjunction with elastomeric impressions are the most accurate means for transferring implant position to a dental cast. Laboratory and finite‐element analysis studies suggest implants with an internal‐type connection show improved stress distribution, but supportive clinical data are lacking. The authors of this review favour a screw‐retained prosthesis for retrievability. Clinical and histological studies show that gold, titanium and zirconia ceramic abutment materials exhibit excellent biological responses, although there is insufficient data on the clinical service provided by zirconia as an implant‐substructure material. The literature does not associate any particular occlusal scheme with superior clinical outcomes. Implant‐borne single crowns offer comparable clinical service to tooth‐borne fixed dental prostheses. However, single‐tooth implant restorations are associated with an increased incidence of biological and technical complications.     

Implant-supported prosthesis misalignment related to the dental arch: a 14-year clinical follow-up

The purpose of this study was to warn the dental community about a possible problem in function with partial implant-supported prostheses used for long periods. The misalignment between natural teeth and the implant-supported prosthesis on teeth 11 and 12, observed in a 14-year clinical follow-up, illustrates the fact. The metal-ceramic crowns were placed in 1995 after a rigorous occlusal adjustment. Evaluations were made at 4, 6, 9, and 14 years, when it was noticed that the restorations were positioned palatally and extruded in comparison with the natural teeth. After 9 years, a greater discrepancy was noticed, with anterior occlusion and esthetic changes. The possible causes have been discussed: occlusal problems, parafunctional habits, and natural movement. The first 2 options were discarded after clinical analysis and diagnosis. Therefore, the natural movement probably deriving from an interaction of mechanical and genetic factors might have been the cause. The implants do not have periodontal ligaments but rather ankylosis, so they do not suffer those movements. This case emphasizes the need to inform patients that implants can last more than 10 years in function, but this is not the case with restorations, which lose function and esthetics and must be replaced.