Failures in implant dentistry

This article describes the many failures and complications that can occur when using implants to support restorations. Most of these failures can be prevented with proper patient selection and treatment planning. Implant failures can be largely classified into four main categories: 1) loss of integration, 2) positional failures 3) soft tissue defects, and 4) biomechanical failures. Each of these will be discussed with examples to illustrate the problem.     

Fabrication of a cement- and screw-retained multiunit implant restoration

Retrieval of cemented implant restorations can be difficult for both the patient and the dentist. The method described in this article combines the advantages of cement- and screw-retained restorations. Abutment screws can be easily reached by the screw access channel prepared in the waxing phase; the restoration can be retrieved without destroying the implants and prosthesis. This article describes a simple and reliable method to fabricate a retrievable cemented prosthesis.     

An Alternative to Splinting Multiple Implants: Use of the ITI System

The restoration of patients with dental implants presents many challenges. Some of the common concerns and problems are difficulty in achieving a passive-fitting cast framework and loosening of prosthesis-retaining screws or abutment screws when using external hex prosthesis connection systems. The ITI system uses a unique connection of the abutment to the prosthesis-anchoring component. Because of this unique connection, many problems encountered with external hex designs have been greatly reduced or eliminated by the ability to more easily restore individual teeth with individual implants. This article will present the rationale for restoration of a patient with implants using individual implant-supported restorations.     

A clinical study of the efficacy of gold-tite square abutment screws in cement-retained implant restorations

PURPOSE: The purpose of this study was to record the effectiveness of Gold-Tite square abutment screws, tightened to 35 Ncm with a torque indicator, in maintaining a clinically stable implant/abutment connection. MATERIALS AND METHODS: The study consisted of 73 patients who were treated with 110 Osseotite implants. All patients were restored with either pre-machined titanium or customized UCLA hexed abutments. All abutments were fabricated per the Gold Standard ZR abutment design of Implant Innovations. All of the abutment screws were Gold-Tite square abutment screws. They were torqued to 35 Ncm with a torque indicator at the time of abutment connection. All crown restorations were cemented to the abutments. Patients were followed for at least 1 year post-occlusal loading. RESULTS: Four patients with 6 implants were lost between the 6- and 12-month recall appointments. Clinical assessments of implant/restoration mobility were made by the author. One abutment screw was found to be loose at the 12-month recall appointment, representing a 99% survival rate. DISCUSSION: These results add to the growing evidence that abutment screws with enhanced surfaces may provide increased screw/implant contact, higher rotational values, and calculated preload values. CONCLUSION: The use of the Gold-Tite square abutment screws, torqued to 35 Ncm, maintained a stable implant/abutment connection that was successful in clinical practice for this minimal evaluation period.     

Advanced alveolar crest atrophy: an alternative treatment technique for maxilla and mandible

A concept of oral implantology for the treatment of advanced crest atrophy is presented: The lateral insertion technique with disk-design implants is less invasive than bone grafting. An implant case demonstrates the simultaneous surgery of an edentulous maxilla and a mandible. Implant loading zones in the anterior and posterior areas of the arch are created with disk-design implants. Their support is tricortical or multicortical. Seven to eight days after surgery, the implants are immediately loaded with fixed esthetic temporaries. After another 40 days, the definitive restorations on the implants can be fabricated. The procedure is safe and shortens chairtime.     

The importance of dental implants

Implant dentistry has evolved into the mainstream of restorative practices all over the world. Maintenance of bone after tooth loss to improve or maintain facial esthetics and improved retention, function, and performance of removable restorations are only some of the advantages for the edentulous patient. No longer are implants considered only when traditional restorations cannot be fabricated. Evidence-based reports indicate implant restorations last longer than those on teeth and the abutment teeth are at less risk of loss or complication.     

A comparison between screw- and cement-retained implant prostheses. A literature review

Implant-supported restorations can be secured to implants with screws (screw-retained), or they can be cemented to abutments which are attached to implants with screws (cement-retained). This literature review discusses the advantages and disadvantages of each method of retention from different aspects. These aspects include: ease of fabrication and cost, esthetics, access, occlusion, retention, incidence of loss of retention, retrievability, clinical prosthesis fit, restriction of implant position, effect on peri-implant tissue health, provisionalization, immediate loading, impression procedures, porcelain fracture, and clinical performance. Peer-reviewed literature published in the English language between 1955 and 2010 was reviewed using PubMed and hand searches. Since the choice of using either method of retention is still controversial, this review article offers some clinical situations that prefer one method of retention over the other. The review demonstrated that each method of retention has certain advantages and disadvantages; however, there are some clinical situations in which it is better to select one method of retention rather than the other.     

What you don't know can hurt you (and your patients)

The goal of modern dentistry is to return patients to oral health in a predictable fashion. The partial and complete edentulous patient may be unable to recover normal function, aesthetics, comfort, or speech with a traditional removable prosthesis. The aesthetics of the edentulous patient are affected as a result of bone atrophy. Continued resorption leads to irreversible facial changes. An implant stimulates the bone and maintains its dimension in a manner similar to healthy natural teeth. As a result, the facial features are not compromised by lack of support. Implant prostheses often offer a more predictable treatment course than traditional restorations. Thus, the profession and the public are becoming increasingly aware of this dental discipline. Between 1983 and 1987 there was a tenfold increase in the number of dentists placing implants and a fourfold increase in the number of implants inserted. Manufacturers' sales have increased from a few million dollars to more than $200 million. Almost every professional journal and lay publication now carries advertisements for implants. Implant dentistry has finally been accepted by organized dentistry. All US dental schools now teach some awareness of implant dentistry. The current trend to expand the use of implant dentistry will continue until every restorative practice uses this modality for abutment support of both fixed and removable prostheses. Do not be the straggler and ignore the advantages of dental implants, because what your patients don't know can hurt them.     

后牙区种植义齿修复完成一年后并发症的临床分析

目的:总结分析后牙区种植义齿修复完成一年后并发症的发生,为提高临床种植义齿长期修复成功率提供参考。方法:统计分析山东大学口腔医院种植中心自2001年至今完成永久修复一年后出现并发症的后牙区种植体共68颗。结果:出现的并发症有:种植体松动脱落7颗,发生率10.3%;慢性种植体周围炎18颗,发生率26.5%;冠、基台、固位螺丝等部件松动19颗,发生率28.0%;种植体、基台、中央螺丝折断7颗,发生率10.3%;食物嵌塞22颗,发生率32.3%。结论:后牙区种植义齿修复完成后一年出现的并发症主要是食物嵌塞、慢性种植体周围炎、上部修复结构松动。这主要与不同种植系统的选择、种植外科操作、上部修复结构的设计制作及患者的使用维护情况有关。采用规范的外科操作、制作精良的上部修复体,以及注重种植修复体的长期随访维护,就会尽可能地避免种植修复并发症的发生,有效地提高种植义齿修复的长期成功率。     

The biocompatibility (cell culture and histologic study) of hydroxy‐apatite‐coated implants created by ion beam dynamic mixing

Titanium implants were coated with hydroxyapatite by using a method of ion beam dynamic mixing. Coated and noncoated plates of titanium were placed in a growth medium with fibroblast cells. Implant screws, coated and noncoated, were inserted in rabbit bones and the animals were euthanized after 7, 27 and 122 days, respectively. The results from the cell culture test showed no visible difference between the specimens. Histologic examination of implant specimens indicated more new bone activity against coated screws at 27 days, and that was more pronounced at 127 days. Although the amount of new bone formation was not significantly different, certain signs of favourable new bone formation could be seen in contact with coated implants compared to the noncoated controls.     

Osseointegrated implants for single tooth replacement: a 1-year report from a multicenter prospective study.

One hundred seven dental implants were inserted to support single tooth restorations in 92 patients participating in a prospective multicenter investigation. Only three implants (2.8%) were lost after 1 year of clinical function. Most of the remaining restorations were esthetically successful by using modified components. The gingival condition was healthy around the single crowns and coincided well with the clinical situation around the permanent teeth. The most obvious problem experienced during the first year was related to loose abutment screws. Twenty-six percent of the screws retaining crowns were retightened during the observation period, but the frequency of loose screws had a tendency to decrease as the study progressed.     

Implant screw mechanics and the settling effect: overview

One of the most serious and prevalent problems associated with the restorative aspect of dental implants is loosening and fracturing of screws. Implant screws should be retightened 10 minutes after the initial torque application as a routine clinical procedure to help compensate for the settling effect. Mechanical torque gauges should be used instead of hand drivers to ensure consistent tightening of implant components to torque values recommended by implant manufacturers.     

Strain development of screw-retained implant-supported fixed restorations: procera implant bridge versus conventionally cast restorations

The aim of this study was to quantify the strain development of screw-retained three-unit implant-supported Procera Implant Bridge restorations. Two groups of screw-retained implant-supported restorations (n = 10) were fabricated by means of casting or computer-aided design/computer-assisted manufacture (CAD/CAM) to fit an in vitro cast situation with two implants. During fixation of the restorations, the emerging strains were recorded using strain gauges attached to the cast material mesially and distally adjacent to the implants. Absolute mean strain development ranged from 29.35 Μm/m to 2,665.80 Μm/m at the different strain gauge locations. Fabrication method had a significant effect on strain development (multivariate analysis of variance, P = .000), with the cast restorations showing significantly higher strain levels compared to the CAD/CAM-fabricated superstructures. CAD/CAM fabrication of screw-retained implant-supported restorations provides greater passivity of fit compared to conventional fabrication methods such as casting.     

Complication rates for various retention types in anterior implant-supported prostheses: A retrospective clinical study

Statement of problemImplant-supported prostheses have typically been retained by cement or screws, each of which has advantages and disadvantages. Two new types of prosthesis with complementary advantages and disadvantages have been proposed: the screw- and cement-retained prosthesis, which combines cement and screw retention, and the antiloosening inner-post screw (ALIPS) type, which uses lateral screws. Both esthetic and functional factors should be considered for anterior prostheses; however, clinical studies of the complication rates of these designs are lacking.PurposeThe purpose of this retrospective clinical study was to evaluate the complications of dental implant-supported restorations with various prosthetic types in the anterior region and to analyze other factors that affect complications.Material and methodsThis study included 51 patients who had 83 implants placed in the anterior region by a single clinician between August 2009 and December 2016. Surgical and prosthetic features were recorded, and implant complications were analyzed.ResultsThere were 45 (55.4%) cement-retained implants, 5 (6.0%) screw- and cement-retained prosthesis implants, and 32 (38.6%) ALIPS-retained implants. Peri-implant mucositis was observed most frequently in the ALIPS type (21.9%), but the biological complications did not differ significantly with the prosthetic type. The most common mechanical complication was loss of retention in the cement type of prosthesis (30.4%) and screw loosening in the ALIPS type (43.8%). Implant complications varied with position (maxilla or mandible) and implantation timing (period from tooth extraction to implant placement).ConclusionsThe complications of implants placed in the anterior region were affected by different factors but did not differ significantly with the type of the retention.     

��ͬ�ڸ�����ֲ�����޸�������ٴ���Ч����

目的 评价不同冠根比的种植单冠修复体短期临床效果。方法 选择2006年1月至2010年12月在中国医科大学附属口腔医院种植中心接受种植单冠修复的152例患者,共172枚螺纹状种植体。计算种植体冠根比（crown-root ratio,CRR）,将所有种植牙按照CRR≤1和1＜CRR＜2分为两组。统计两组种植牙5年累计存留率,并测量两组种植牙在修复后3个月、1年、2年种植体周围骨吸收的数值。结果 共有5例患者5枚种植体脱落,CRR≤1组和1＜CRR＜2组种植牙5年累计存留率分别为96.52%和93.27%,差异无统计学意义（P＞0.05）;两组种植牙在修复后3个月、1年、2年种植体周围骨吸收量差异均无统计学意义（均P＞0.05）。结论 不同冠根比的种植单冠修复体5年累计存留率、周围骨吸收量均无明显差异,冠根比CRR≤1和1＜CRR＜2种植单冠修复体的短期临床效果均较好。     

不同冠根比种植单冠修复体短期临床疗效评价

目的 评价不同冠根比的种植单冠修复体短期临床效果。方法 选择2006年1月至2010年12月在中国医科大学附属口腔医院种植中心接受种植单冠修复的152例患者,共172枚螺纹状种植体。计算种植体冠根比（crown-root ratio,CRR）,将所有种植牙按照CRR≤1和1＜CRR＜2分为两组。统计两组种植牙5年累计存留率,并测量两组种植牙在修复后3个月、1年、2年种植体周围骨吸收的数值。结果 共有5例患者5枚种植体脱落,CRR≤1组和1＜CRR＜2组种植牙5年累计存留率分别为96.52%和93.27%,差异无统计学意义（P＞0.05）;两组种植牙在修复后3个月、1年、2年种植体周围骨吸收量差异均无统计学意义（均P＞0.05）。结论 不同冠根比的种植单冠修复体5年累计存留率、周围骨吸收量均无明显差异,冠根比CRR≤1和1＜CRR＜2种植单冠修复体的短期临床效果均较好。     

Analysis of incidence and associated factors with fractured implants: a retrospective study

Osseointegrated threaded titanium screw-type implants rarely lose integration after the first year of clinical function. Implant failure can occur for other reasons, with implant fracture being one of the major reasons for late failure. The purpose of the present study was to determine the incidence of implant fracture in completely edentulous and partially edentulous arches and to determine what factors may predispose an implant to a higher fracture risk. A retrospective evaluation of 4,937 implants was performed to determine the incidence of and factors common to fractured implants from a sample of implants placed and restored in one institutional setting. Based on the results of this study, the following observations were made: implants fracture at similar rates in the maxilla as in the mandible (0.6%), implant fractures occur more frequently in partially edentulous restorations (1.5%) than in restorations of completely edentulous arches (0.2%), all observed fractures occurred with commercially pure 3.75-mm-diameter threaded implants, and prosthetic or abutment screw loosening preceded implant fracture for the majority of the implants. More studies would be helpful to further explore the relationship and progression of factors associated with implant fracture.     

Xive Implant System的临床应用评价

目的:评价XiveImplantSystem的临床效果。方法:应用XiveImplantSystem对失牙区进行即刻或延期种植,部分采用埋入或二次手术方式,部分采用一次手术直接安装愈合基台,对62例患者植入100枚种植体,金属烤瓷冠及8例后牙区因颌龈距过低而采用铸造冠修复。临床随访观察三年六个月。结果:种植体成功率100%,种植体周牙槽骨吸收<0.2mm/年,种植体周围炎2枚,固定螺丝松动2枚。结论:XiveImplantSystem适用于牙列缺损及缺失的延期或即刻修复。     

The ZiReal Post: A new ceramic implant abutment

Restorations in the anterior esthetic zone present significant challenges in both the surgical and prosthetic phases of implant dentistry. Titanium has been established as the material of choice for endosseous implants, resulting in a high degree of predictability. Many types of implants require transmucosal abutments to retain implant restorations. Ceramics may be the ideal material to replace natural teeth, but most transmucosal abutments are made of titanium. However, ceramics may also be used as abutments in implant restorations. This combination of ceramics for abutment and crown provides better translucency for the implant restoration than is available with metal abutments and porcelain-fused-to-metal crowns. Ceramic abutments and implant restorations also minimize the gray color associated with metal components that is transmitted through the peri-implant tissues. Customized emergence profiles also may be obtained with ceramic abutments; this generally improves the predictability and consistency of the esthetics obtainable in implant restorations. Zirconia as a ceramic material offers not only outstanding material properties but also a well-documented biocompatibility.
CLINICAL SIGNIFICANCE
This article discusses the clinical and laboratory features of a new ceramic abutment, ZiReal™ Post (Implant Innovations, Inc., Palm Beach Gardens, Florida).     

The impact of osseointegrated implants as an adjunct and alternative to conventional periodontal prosthesis

In the last 4 decades, the developments of osseointegrated titanium implants have led to the success of contemporary dentistry. Endosseous implant-supported restorations delivered in accordance with the traditional Branemark protocol have proven to be highly predictable. Today, implants are becoming increasingly common in dental care and provide more therapeutic options, but treatment planning and the sequencing of therapy are critical in implant-assisted and implant-supported cases. Implant prostheses give patients and dentists more options in treatment planning, but also present challenging decisions regarding implant surgery. In this article, the author explains how to apply the periodontal prosthesis philosophy, concepts, principles, and techniques to the implant-supported prosthesis.