Diagnosis for dental implant using computed tomography and precise implantation using modified stent

The diagnosis of jaw bones using X-ray computerized tomography is effective to decide the method of implantation, the position of the implant, and the direction for the insertion of the implant. However, it is difficult to apply anatomical information to the superstructures of implants, as well as to prepare implant sockets at the proper site by using an ordinary surgical stent. This would affect the effectiveness of the X-ray computerized tomography considerably. The X-ray computerized tomography with a diagnostic stent has been used in our clinic. CT multiplaner reconstruction images with radiopaque markers are useful to examine the adaptability of implant and to determine an appropriate site of implantation for an ideal prosthesis. Moreover, the diagnostic stent is modified to the surgical stent by drilling guide holes to reproduce a precise direction for inserting implant. By applying this stent, it is possible to reproduce the optimal site and direction for the placement of implant. In this report, two cases, which were treated with diagnosis and the placement of implants by using this technique, were studied. One was a case of overdenture and the other was that of upper anterior prostheses. In both cases, precise implantation was achieved by using this technique.     

Bone augmentation techniques

BACKGROUND: The advent of osseointegration and advances in biomaterials and techniques have contributed to increased application of dental implants in the restoration of partial and completely edentulous patients. Often, in these patients, soft and hard tissue defects result from a variety of causes, such as infection, trauma, and tooth loss. These create an anatomically less favorable foundation for ideal implant placement. For prosthetic-driven dental implant therapy, reconstruction of the alveolar bone through a variety of regenerative surgical procedures has become predictable; it may be necessary prior to implant placement or simultaneously at the time of implant surgery to provide a restoration with a good long-term prognosis. Regenerative procedures are used for socket preservation, sinus augmentation, and horizontal and vertical ridge augmentation. METHODS: A broad overview of the published findings in the English literature related to various bone augmentation techniques is outlined. A comprehensive computer-based search was performed using various databases that include Medline and PubMed. A total of 267 papers were considered, with non-peer-reviewed articles eliminated as much as possible. RESULTS: The techniques for reconstruction of bony defects that are reviewed in this paper include the use of particulate bone grafts and bone graft substitutes, barrier membranes for guided bone regeneration, autogenous and allogenic block grafts, and the application of distraction osteogenesis. CONCLUSIONS: Many different techniques exist for effective bone augmentation. The approach is largely dependent on the extent of the defect and specific procedures to be performed for the implant reconstruction. It is most appropriate to use an evidenced-based approach when a treatment plan is being developed for bone augmentation cases.     

Trajectory surgical guide stent for implant placement.

This article describes a new implant placement surgical guide that gives both implant location and trajectory to the surgeon. Radiopaque markers are placed on diagnostic dentures and a lateral cephalometric radiograph is made that shows the osseous anatomy at the symphysis and the anterior tooth location. The ideal implant location and trajectory data are transferred to a surgical stent that programs the angle and location of the fixtures at time of surgery. The stent has the additional benefit of acting as an occlusion rim, a mouth prop, and tongue retractor. Use of this stent has resulted in consistently programming the placement of implant fixtures that are prosthodontically ideal.     

Dental implant treatment for patients with psychiatric disorders

The literature with respect to whether or not psychiatric disorders represent a contraindication to dental implant treatment is sparse and contradictory. This paper describes three cases in which patients with psychiatric disorders were provided with dental implant retained prostheses. It is concluded that mental health disorders are not necessarily a contraindication to dental implant treatment and dental implant treatment can provide valuable psychological support. If any doubt exists about the effect of a psychiatric disorder on the prognosis of implant treatment the opinion of a psychiatrist should be obtained. The development of liaison psychiatry for dental hospitals should be seen as an ideal.     

血浆基质在口腔种植水平骨增量中的应用

牙齿缺失伴随着牙槽骨吸收或缺损,导致骨量和软组织量不足。种植治疗除恢复缺失牙的咀嚼功能外,还需恢复牙弓的轮廓和外形,引导骨再生术是骨增量的常用手段。异种颗粒状骨替代材料因其降解时间长、免疫反应低等优点,在临床水平骨增量领域应用广泛,但存在操作不便、成骨活性低等问题。血浆基质能有效提高口腔组织再生效果、减少术后并发症的出现,在口腔组织再生中的应用逐渐增多。本文首先介绍了血浆基质在水平骨增量中的主要应用形式(固态血浆基质膜、血浆基质骨块),并根据临床常用的骨增量决策方案,即是否能够在理想位置植入种植体以及植入后是否存在骨开裂对水平骨缺损进行重新分类,其中Ⅰ类水平骨缺损为缺牙位点骨量可供植入理想尺寸的种植体,且种植体周围无骨开裂,但牙槽骨轮廓比非缺牙区凹陷的情况;Ⅱ类水平骨缺损为缺牙位点骨量根据未来修复体位置确定的种植位点植入理想尺寸种植体后,种植体三侧均有骨,但颊侧骨壁存在骨开裂(骨开裂长度小于种植体长度的50%)的情况;Ⅲ类水平骨缺损为缺牙位点骨量不足以在理想位置植入理想尺寸的种植体,需要先行植骨恢复骨量以利于种植体植入的情况。本文随后对血浆基质在不同水平骨缺损类型中的应用方法进行阐述:...     

Inadequate implant angulation resulting from oroantral fistula: case report.

Successful implant surgery is largely dependent on good treatment planning and careful surgery. A complete treatment plan must encompass both surgical and prosthetic considerations for the implant restoration. Some compromised implants are restorable, and the result can be acceptable if they can be adjusted into a more ideal position. The goals of the segmental osteotomy are the preservation of a healthy dental unit, the creation of a more ideal environment for dental restoration and occlusal reconstruction, the optimization of cost effectiveness, and the minimization of edentulous space. The purpose of this study is to present the segmental maxillary osteotomy to reposition the alveolar segment with its implant that was in a highly compromised situation.     

Horizontal bone augmentation: the decision tree

The emergence of implant dentistry has led to the need for bone augmentation procedures. With the removal of a tooth, there is an inevitable three-dimensional (3D) loss of alveolar bone. More often than not, horizontal bone loss occurs at a faster rate and to a greater extent compared to vertical bone loss. This led to the development of several horizontal bone augmentation techniques, such as guided bone regeneration, ridge expansion, distraction osteogenesis, and block grafts. These proposed augmentation techniques aim to place the implant in an ideal 3D position for successful restorative therapy. The literature has shown that horizontal bone augmentation is fairly predictable if certain criteria are fulfilled. However, with numerous techniques and materials currently available, it is difficult to choose the most suitable treatment modality. A search of the literature available was conducted to validate the decision-making process when planning for a horizontal ridge augmentation procedure. The decision tree proposed in this paper stems from the 3D buccolingual bone width available at the site of implant placement (? 3.5 mm, < 3.5 mm, or 4 to 5 mm). In each dimension, techniques are advised after considering factors such as the tissue thickness, the arch position, and the availability of autogenous bone. The decision tree provides insight on how clinicians can choose the most appropriate and predictable horizontal ridge augmentation procedure to minimize unnecessary complications.     

A restoratively driven ridge categorization, as determined by incorporating ideal restorative positions on radiographic templates utilizing computed tomography scan analysis

Background: The introduction of implants into the field of dentistry has revolutionized the way we evaluate edentulous ridges. In an attempt to evaluate the deficient edentulous ridge, numerous classification systems have been proposed. Each of these classification systems implements a different approach for evaluating and planning treatment for the ridge deficiency.
Purpose: The purpose of the present investigation was to propose a restoratively driven ridge categorization (RDRC) for horizontal ridge deformities based on an ideal implant position as determined through implant simulation, utilizing computed tomography (CT) scan images.
Materials and Methods: Radiographic templates were developed to capture the ideal restorative tooth position. Measurements were performed using CT scan software in a cross-sectional view and by virtual placement of a parallel-sided implant with a 3.25-mm diameter.
Results: Edentulous ridges were divided into five groupings: Group I, simulated implants with at least 2 mm of facial bone, accounted for 19.4% of ridges; Group II, simulated implant completely surrounded by bone, with less than 2 mm of facial plate thickness, accounted for 10.4% of ridges; Group III, wherein dehiscences are detected but no fenestrations are present, accounted for 33.3% of ridges; Group IV, wherein fenestrations are detected but no dehiscence is present, accounted for 6.3% of ridges; and Group V, wherein both dehiscences and fenestrations are present, accounted for 30.6% of ridges.
Conclusion: The use of RDRC indicates that a high number of cases in the maxillary anterior area would require augmentation procedures in order to achieve ideal implant placement and restoration.     

Bone graft sandwich osteotomy to correct a malpositioned dental implant

As a result of inadequate planning, poor judgment, or losing one's orientation during surgery, implants may be placed in positions or at angulations that are less than ideal. The purpose of this report is to describe an alternative technique for the correction of a malpositioned osseointegrated implant by means of a maxillary anterior single implant segmental osteotomy associated with a ‘sandwich’ bone graft technique. The technique described provides an alternative option for the surgeon faced with a malpositioned endosseous implant. It allows for a predictable result with preservation of the cervical gingival architecture, creates a more ideal environment for dental restoration, reduces treatment time compared to other techniques, and does so in a cost-effective manner.     

Managing congenitally missing lateral incisors. Part I: Canine substitution

Dentists often encounter patients with missing or malformed teeth. The maxillary lateral incisor is the second most common congenitally absent tooth. There are three treatment options that exist for replacing missing lateral incisors. They include canine substitution, a tooth-supported restoration, or a single-tooth implant. Selecting the appropriate option depends on the mal-occlusion, specific space requirements, tooth-size relationship, and size and shape of the canine. The ideal treatment is the most conservative option that satisfies individual esthetic and functional requirements. Often the ideal option is canine substitution. Although the orthodontist positions the canine in the most esthetic and functional location, the restorative dentist often needs to place a porcelain veneer or crown to re-create normal lateral incisor shape and color.
This article closely examines patient selection and illustrates the importance of interdisciplinary treatment planning to achieve optimal esthetics. It is the first in a three-part series discussing the three treatment alternatives for replacing missing lateral incisors.     

Managing congenitally missing lateral incisors. Part III: single-tooth implants

Three treatment options exist for the replacement of congenitally missing lateral incisors. They include canine substitution, a tooth-supported restoration, and a single-tooth implant. Selecting the appropriate treatment option depends on the malocclusion, anterior relationship, specific space requirements, and condition of the adjacent teeth. The ideal treatment is the most conservative option that satisfies individual esthetic and functional requirements.
Today, the single-tooth implant has become one of the most common treatment alternatives for the replacement of missing teeth. This article closely examines the many interdisciplinary issues that arise when treatment planning the placement of single-tooth implants in patients with congenitally missing lateral incisors. The specific criteria that must be evaluated illustrate the importance of an interdisciplinary treatment approach to achieve optimal esthetics and long-term predictability. This is the final article of a three-part series discussing the three treatment alternatives for replacing congenitally missing lateral incisors.     

Evaluation of bone ingrowth into porous titanium implant: histomorphometric analysis in rabbits

A porous material for bone ingrowth with adequate pore structure and appropriate mechanical properties has long been sought as the ideal bone-implant interface. This study aimed to assess in vivo the influence of three types of porous titanium implant on the new bone ingrowth. The implants were produced by means of a powder metallurgy technique with different porosities and pore sizes: Group 1 = 30 % and 180 μm; Group 2 = 30% and 300 μm; and Group 3 = 40% and 180 μm;. Six rabbits received one implant of each type in the right and left tibiae and were sacrificed 8 weeks after surgery for histological and histomorphometric analyses. Histological analysis confirmed new bone in contact with the implant, formed in direction of pores. Histomorphometric evaluation demonstrated that the new bone formation was statistically significantly lower in the group G1 than in group G3, (P = 0.023). Based on these results, increased porosity and pore size were concluded to have a positive effect on the amount of bone ingrowth.     

The use of guided tissue regeneration to facilitate ideal prosthetic placement of implants.

Placement of implant fixtures in an ideal position for restoration is not often possible using standard protocol, because most patients lack sufficient bone in the alveolar process. To facilitate ideal restorative placement of implant fixtures, principles of guided tissue regeneration can be used to provide adequate bone and prevent dehiscence and fenestration of the implant. Four cases of such treatment are presented.     

A review of the functional and esthetic requirements for dental implants

BACKGROUND: The esthetic replacement of teeth has become an important standard for implant dentistry. While defining this goal has not been difficult, the ability to restore implants esthetically has been fraught with obstacles and sometimes has not been attainable. The purpose of this review is to summarize essential anatomical and surgical considerations for cosmetic implant dentistry. METHODS: This article provides a summary of the predominant findings from clinical studies and case reports that help develop implant surgical guidelines for better esthetic outcomes. RESULTS: Soft- and hard-tissue requirements for placing an implant in an ideal position are defined. The authors discuss the best treatment approaches as well as the limitations associated with esthetic implant placement. They evaluate the available data specifically for the maxillary anterior sextant, since this anatomical region has higher esthetic demands. CONCLUSIONS: Several parameters and various surgical techniques have been developed to manipulate soft- and hard-tissue contours and to control the esthetic outcome for implant-supported restorations. CLINICAL IMPLICATIONS: It is essential for practitioners to understand the anatomical basis for and limitations of implant dentistry in the esthetic zone.     

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。     

Maxillary implant-supported bar overdenture and mandibular implant-retained fixed denture using CAD/CAM technology and 3-D design software: a clinical report

The implant-supported bar overdenture and the implant-retained fixed complete denture are appropriate treatment choices for patients with inadequate bone volume in the posterior maxilla and mandible, respectively. Computer-aided design/computer-aided manufacturing (CAD/CAM) technology has broadened the scope and application of those treatment options, allowing for prosthodontically-driven implant placement and ideal substructure design for optimal esthetics and biomechanics. This report describes the fabrication of a maxillary implant-supported milled titanium bar with attachments and an overdenture, and a mandibular implant-retained fixed complete denture with milled titanium substructure.     

Influence of the 3-D bone-to-implant relationship on esthetics

There are biologic limits of the soft tissue dimension around implants; therefore, the limiting factor for the esthetic result of implant therapy is the bone level at the implant site. Clinicians must focus on the 3-D bone-to-implant relationship to establish the basis for an ideal and harmonic soft tissue situation that is stable over a long period. In some situations, missing bone is a limiting factor for esthetics; in others, it is possible to regenerate new bone around implants. As a certain amount of bone resorption occurs around implants as soon as the implant is in contact with the oral environment, the distance between an implant and adjacent tooth, as well as the distance between two implants, is as important as the bone volume on the buccal side of the implant head and in the papillary area, especially for the long-term result. This article discusses the 3-D bone-to-implant relationship and its influence on soft tissue esthetics around implants.     

Surgical navigation in oral implantology

The ability to generate 3-dimensional volumetric images of the maxillofacial area has allowed surgeons to evaluate anatomy before surgery and plan for the placement of implants in ideal positions. However, the ability to transfer that information to surgical reality has been the most challenging part of implant dentistry. With the advent of computer-assisted surgery, the surgeon may now navigate through the entire implant procedure with extremely high accuracy. A new portable laptop navigated system for oral implantology is discussed as an adjunct for complex implant cases.     

Implant prosthodontic design as a predisposing or precipitating factor for peri-implant disease: A review

Over the past decade, emerging evidence indicates a strong relationship between prosthetic design and peri-implant tissue health. The objective of this narrative review was to evaluate the evidence for the corresponding implant prosthodontic design factors on the risk to peri-implant tissue health. One of the most important factors to achieve an acceptable implant restorative design is the ideal implant position. Malpositioned implants often result in a restorative emergence profile at the implant-abutment junction that can restrict the access for patients to perform adequate oral hygiene. Inadequate cleansability and poor oral hygiene has been reported as a precipitating factors to induce the peri-implant mucositis and peri-implantitis and are influenced by restorative contours. The implant–abutment connection, restorative material selection and restoration design are also reported in the literature as having the potential to influence peri-implant sort tissue health.     

Immediate placement of osseointegrated dental implants into extraction sockets: advantages and case reports.

Osseointegrated dental implants have proven to be predictably successful when appropriate guidelines are followed. The technique as outlined by br?nemark includes a post-extraction period of up to 12 months in order to allow for bone healing. This delay, combined with ridge resorption following extraction, may contribute to several problems. Insufficient available bone for ideal implant placement and prolonged treatment time are two common difficulties. Recently, several investigators have reported immediate placement of dental implants into extraction sockets achieving excellent results while, at the same time, minimizing or eliminating the above-mentioned difficulties. This paper will discuss the technique of immediate placement of osseointegrated dental implants into extraction sockets and its potential advantages. A future article will detail surgically-related difficulties with this technique.