Electromyographic analysis of masticatory and neck muscles in subjects with natural dentition, teeth-supported and implant-supported prostheses

Objectives: To compare the electromyographic (EMG) characteristics of masticatory and neck muscles in patients with natural dentition, teeth‐supported prostheses and implant‐supported prostheses. Materials and methods: Twenty‐five subjects aged 40–80 years were examined. Five patients had maxillary and mandibular implant‐supported fixed prostheses; five patients had mandibular implant‐supported fixed prosthesis and maxillary removable complete denture; seven patients had implant‐supported fixed prosthesis (one arch) and natural dentition or full‐arch tooth‐fixed prosthesis (one arch); and eight control subjects had natural dentition or single tooth‐fixed prostheses. Surface EMG of masseter, temporal and sternocleidomastoid muscles was performed during maximum teeth clenching and unilateral gum chewing. Interarch dental contacts were assessed with shim stocks. Results: All groups had similar interarch dental contacts (P>0.05). During clenching, patients with maxillary and mandibular implant‐supported fixed prostheses had unbalanced standardized masseter and temporalis anterior activities (74%), with significantly larger values found in the other patients and control subjects (all mean values larger than 86%, P=0.017). All patients chewed with significantly larger muscular potentials than control subjects (on average, 1434–2100 μV s vs. 980 μV s, P=0.04), and had altered muscular patterns (left side, P=0.021). The patients with one arch with natural dentition/tooth fixed prostheses had chewing muscular patterns similar to the control subjects. Conclusions: Clenching with the analyzed prostheses was performed with a relative increment of temporalis activity. Neuromuscular coordination during chewing was larger in patients who maintained their teeth or dental roots, independently from the number of dental contacts.     

Transition from Failing Dentition to Full‐Arch Fixed Implant‐Supported Prosthesis with a Staged Approach Using Removable Partial Dentures: A Case Series

The present retrospective case series is aimed at evaluating a staged approach using a removable partial denture (RPD) as an interim prosthesis in treatment to correct a failing dentition until such time as a full‐arch fixed implant‐supported prosthesis may be inserted. Eight patients, who had undergone maxillary full‐arch rehabilitation with dental implants due to poor prognosis of their dentitions, were analyzed. All treatment included initial periodontal therapy and a strategic order of extraction of hopeless teeth. An RPD supported by selected teeth rehabilitated the compromised arch during implant osseointegration. These remaining teeth were extracted prior to definitive prosthesis delivery. Advantages and drawbacks of this technique were also recorded for the cases presented. Among the advantages provided by the staged approach are simplicity of fabrication, low cost, and ease of insertion. Additionally, RPD tooth support prevented contact between the interim prosthesis and healing abutments, promoting implant osseointegration. The main drawbacks were interference with speech and limited esthetic results. Implant survival rate was 100% within a follow‐up of at least 1 year. The use of RPDs as interim prostheses allowed for the accomplishment of the analyzed rehabilitation treatments. It is a simple treatment alternative for patients with a low smile line.     

Individual Lithium Disilicate Crowns in a Full‐Arch,Implant‐Supported Rehabilitation: A Clinical Report

This clinical report presents the clinical outcome of a maxillary full‐arch implant‐supported fixed rehabilitation with lithium disilicate reinforced glass ceramic monolithic crowns opposing a mandibular metal‐acrylic implant‐supported fixed rehabilitation in a 62‐year‐old woman. Eight implants were successfully placed (four maxillary, four mandibular), and no complications occurred in the postoperative or maintenance periods. Six months after delivery, the maxillary and mandibular prostheses were found to be clinically, biologically, and mechanically stable, and the patient was satisfied with the esthetics and her ability to function. Although the present indications for the use of lithium disilicate are still restricted to tooth‐borne restorations, it is possible to successfully rehabilitate edentulous patients through implant‐supported fixed prostheses using lithium disilicate reinforced glass ceramic monolithic crowns.     

Full‐Arch Implant‐Supported Fixed Dental Prosthesis Retained by a Combination of Galvano‐Telescopic Copings and Screws: A Clinical Report

Full‐arch screw‐retained implant‐supported fixed dental prostheses have a high long‐term success rate and are considered the gold standard by many clinicians. However, accurate fabrication of a passive fit long‐span prosthesis can be challenging. A novel intraoral adhesion method using galvano‐telescopic copings was proposed as a way of improving prosthetic fit for edentulous patients. This report describes the treatment of a 74‐year‐old female with a full‐arch implant‐supported dental prosthesis, supported by a combination of galvano‐telescopic copings and screws to prevent retention loss. Four years have passed since this superstructure was placed, during this time she exhibited a good clinical course with no inflammation noted in surrounding tissues. Treatment with an implant‐supported fixed dental prosthesis, retained by a combination of galvano‐telescopic copings and screws, can be a useful alternative treatment for edentulous patients.     

A Prosthesis Retention System for Full‐Arch,Fixed, Implant‐Supported Prosthesis

Full‐arch, fixed, implant‐supported prostheses can be designed to be cement‐ or screw‐retained. Both retention mechanisms have a few inherent disadvantages. A fixed attachment system has been introduced to circumvent the disadvantages of both screw and cement retention. This system eliminates the screw access holes and the use of cement. The number of intraoral procedures required is also reduced. The purpose of this article is to report a case using the Locator F‐Tx Attachment System to facilitate fabrication of an esthetic, clinician‐retrievable, full‐arch implant‐supported fixed dental prosthesis.     

Patient Evaluation of Treatment with Fixed Prostheses Supported by Implants or a Combination of Teeth and Implants

PURPOSE: The objective of this study was to compare treatment outcomes among subjects with complete arch fixed prostheses in the maxilla, supported by implants or a combination of natural teeth and dental implants. MATERIALS AND METHODS: Twenty-one subjects with maxillary tooth- and implant-supported fixed prostheses and 21 subjects with maxillary implant-supported fixed prostheses were identified and included in the study. All abutment teeth in the group with tooth- and implant-supported prostheses were provided with cemented copings that incorporated threads for vertical locking screws. Frameworks were fabricated with a gold alloy that was veneered with acrylic resin or ceramic materials. All frameworks were screw-retained to implants and copings. Frameworks in the group with implant-supported prostheses were fabricated with milled titanium or gold alloy to which denture teeth and resin base material were applied. All prostheses had a minimum of 8 units, at least 4 of which were in one quadrant. Subjects in both groups were mailed a questionnaire consisting of 15 questions focused on various factors related to treatment outcome, such as oral function and patient satisfaction. RESULTS: The response rate was 86%. Both groups reported a high satisfaction rate for most items with few regretting their choice of treatment. Most individuals in both groups reported great improvement in chewing ability and few reported phonetic disturbances. No statistically significant differences were found between the groups. CONCLUSION: The results of the present study showed similarity in questionnaire responses between the 2 groups of participants. High satisfaction was reported both among subjects who received a complete arch fixed prosthesis in the maxilla supported by dental implants only, as well as among those whose prostheses were supported by a combination of natural teeth and dental implants.     

Management of a Fractured Multiunit Maxillary Implant‐Supported Fixed Prosthesis with Stripped Abutment Screws Using a Hybrid Cement‐Retained and Screw‐Retained Design: A 5‐Year Follow‐Up Clinical Report

Fracture and loosening of implant‐supported prostheses (ISPs) are complications encountered in routine dental practice. In the present report, management of a fractured maxillary full‐arch cement‐retained (CR) fixed dental prosthesis supported by six implants is presented. Due to stripped screws, complications were encountered that prevented the retrieval of two of the six abutment screws, which was managed by using a hybrid retention approach, whereby a single full‐arch CR and screw‐retained (SR) ISP was used. The techniques used to successfully retrieve four of the abutment screws are described. The final retention design involved a combination of three CR and three SR restorations, which offers the advantages of both retention designs.     

联合支持早期种植修复前牙缺失临床观察

目的:观察应用非埋植型种植体与天然牙联合式支持早期修复前牙缺失的临床效果。方法:对73例前牙缺失患者植入95枚种植体并早期加载完成义齿修复,临床观察6～48个月。结果:成功率96.8%,修复体各项指标正常。结论:应用CDIC非埋植锥状种植体修复前牙缺失,采用种植牙——天然牙联合支持早期加载,可缩短修复周期,满足患者的美观要求。     

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.     

Use of Vacuum‐Formed Templates to Guide Tooth Preparation and Insertion of Interim Restorations

Ideal tooth preparation and interim prostheses are critical to a predictable esthetic and functional outcome in the treatment of full‐mouth‐fixed restorations. During the treatment stages, multiple procedures need to be considered for a successful and predictable outcome. These include the parallel preparation of multiple abutment teeth followed by the relining of the interim prostheses. The purpose of this article is to describe a technique to simplify tooth preparation and facilitate subsequent insertion of a complete‐arch‐fixed interim prosthesis using vacuum‐formed templates.     

天然牙-种植体联合支持式义齿的应力分析

目的:比较以常规固定桥、固定式套筒冠和CEKA冠外精密附着体为上部结构的天然牙-种植体联合支持义齿的应力分布情况,寻求联合支持义齿上部结构的优化设计方案。方法:利用ANSYS三维有限元法,建立下颌右侧第一磨牙缺失、以下颌第二前磨牙和种植体(位于下颌第二磨牙)联合支持局部固定义齿的三维有限元模型,采用分散垂直和分散斜向(45°)两种加载方式(总加载力200N)。结果:2种加载条件下,固定式套筒冠和CEKA附着体都明显降低了种植体和天然牙周围骨组织的应力,垂直加载时,前者应力值低于后者;斜向加载时,后者低于前者,但后者会使天然牙局部应力有所增加。斜向加载时,种植体及其周围骨组织和天然牙及其周围骨组织的应力值均大于垂直加载条件下的应力值。结论:固定式套筒冠和CEKA附着体均能改善联合支持义齿的应力分布,CEKA附着体对侧向力的缓冲作用较优。     

Biomechanical Evaluation of Tooth‐ and Implant‐Supported Fixed Dental Prostheses with Various Nonrigid Connector Positions: A Finite Element Analysis

Purpose: In the tooth‐ and implant‐supported fixed dental prosthesis (FDP), rigid and nonrigid connector (NRC) designs have been preferred by clinicians for many years. The aim of this study was to analyze the stress distribution on the connecting areas of the superstructure and supporting structure of the tooth‐ and implant‐supported FDP designs under both static vertical and oblique occlusal loads. Materials and Methods: Four 2D finite element analysis (FEA) models were prepared presuming that the first and second molars were missing, and that the implant (3.80‐mm diameter × 13‐mm length) was placed in the second molar NRC design and patrix‐matrix position supported by teeth/implants. Nonlinear contact elements were used to simulate a realistic interface fixation within the implant system and the sliding function of the NRC. Supporting periodontal ligament and alveolar bone (cortical and trabecular) were also modeled. Linear static analysis was performed on the prepared 2D solid models with a total masticatory force of 250 N (50 N for premolar, 100 N for first molar, 100 N for second molar), 0° (at a right angle) and 30° to the long axis of the supports. The maximum equivalent Von Mises (VM_Max) was analyzed around the supporting teeth/implant and connector areas on tooth‐ and implant‐supported FDP. Results: The simulated results indicated that the highest level of VM_Max (400.377 MPa) was observed on the NRC with the matrix positioned on the implant site of tooth‐ and implant‐supported FDP under vertical occlusal load. The highest level of VM_Max (392.8 MPa) under oblique occlusal load was also observed on the same model; however, the lowest VM_Max value around implants was observed with the NRC when the patrix was positioned on the implant site of the FDP. Under vertical occlusal loads, in designs where the NRC was placed on the implant site, the stress formed around the implant decreased when compared to the designs where the NRCs were positioned on the tooth site. Conclusions: The efficiency of the NRC exhibited varying behavior depending on the direction of the load applied. The use of the patrix part of the NRC on the implant site may be more efficient in reducing the stress formation around the implant.     

Telescopic Overdenture Supported by a Combination of Tooth and an Implant: A Clinical Report

The conventional modality of treatment of partial edentulousness with reduced number of teeth was to render them complete edentulous and provide them complete denture or an overdenture with support of few remaining teeth. The goal of maintenance of roots are to prevent alveolar bone resorption, provide better load transmission, maintain sensory feedback and achieve better stability of denture with emphasis on psychological aspect of not being completely edentulous. Over the recent past titanium dental implants have been successfully used as tooth replacement with predictable results. A combination of tooth and implant support is well documented for fixed partial dentures but rarely for overdentures. This clinical report aims at evaluation of tooth root and implant supported mandibular overdenture treatment with telescopic coping.     

Attachment‐Retained Gingival Prosthesis for Implant‐Supported Fixed Dental Prosthesis in the Maxilla: A Clinical Report

The rehabilitation of edentulous maxillae is a complex procedure due to the involvement of esthetic and functional requirements. A trial maxillary denture can be used to identify the need for adequate upper lip support when replacing removable complete dentures by implant‐fixed dental prostheses. This clinical report describes the outcome of the rehabilitation of an edentulous atrophic maxilla with unfavorable maxillomandibular relationship and deficient upper lip support. A trial denture was fabricated and used to diagnose the need for a prosthesis capable of restoring the upper lip support. The reduced upper lip support was also confirmed by a lateral cephalogram. The patient was rehabilitated by an implant‐fixed dental prosthesis associated with an attachment‐retained gingival prosthesis. The case presented shows that when loss of upper lip support is detected and the patient does not wish to undergo further surgical reconstruction procedure, the retention of a gingival prosthesis using a ball attachment is a satisfactory treatment option.     

Retrospective evaluation of complete-arch fixed partial dentures connecting teeth and implant abutments in patients with normal and reduced periodontal support

STATEMENT OF PROBLEM: The clinical outcome of complete-arch fixed prostheses supported by implants and natural tooth abutments in patients with normal or reduced periodontal support has been reported by few studies, with controversial results. PURPOSE: The purpose of this study was to report on the implant success rate, prosthetic complications, and the occurrence of tooth intrusion, when complete-arch fixed prostheses, supported by a combination of implants and teeth, were fabricated for patients with normal and reduced periodontal support. MATERIAL AND METHODS: Nineteen patients with residual teeth that served as abutments were consecutively treated with combined tooth- and implant-supported complete-arch fixed prostheses and were retrospectively evaluated after a period varying from 24 to 94 months. Nine patients showed reduced periodontal support as a result of periodontal disease and treatment (RPS group), and 10 patients had normal periodontal support of the abutment teeth (more than 2/3 of periodontal support [NPS group]). Ninety implants and 72 tooth abutments were used to support 19 fixed partial dentures. Screw- and cement-retained metal-ceramic and metal-resin prostheses were fabricated with rigid and nonrigid connectors. Implant survival and success rates, occurrence of caries and tooth intrusion, and prosthetic complications were recorded. The number of teeth, implants, prosthetic units, fixed partial dentures, and nonrigid connectors were compared with a t test to assess differences between the 2 groups, while data for the occurrence of intrusions and prosthetic complications were compared with the Fisher exact test (alpha=.05). RESULTS: One of the 90 implants was lost (99% survival rate) over 24 to 94 months, while 3 implants showed more than 2 mm of crestal bone loss (96% success rate) over the same period. No caries were detected, but 5.6% (4/72) of the abutment teeth exhibited intrusion. Intrusion of abutment teeth was noted in 3 patients who had normal periodontal support (13% of teeth in NPS group) of the abutment teeth and was associated with nonrigid connectors. No intrusion of teeth was noted in the patients exhibiting reduced periodontal support regardless of the type of connector or when a rigid connector was used for either group. The number of intruded teeth was significantly greater in patients with intact periodontal support (P=.03). CONCLUSIONS: Complete-arch fixed prosthesis supported by implant and tooth abutments may be associated with intrusion of teeth with intact periodontal support when nonrigid connectors are used to join the implant- and tooth-supported sections of the prostheses. However, fixed partial dentures supported by implants and teeth with reduced periodontal support were not associated with tooth intrusion, regardless of the type of connectors used.     

Combination of natural teeth and osseointegrated implants as prosthesis abutments: a 2-year longitudinal study.

Twenty-three patients with Kennedy Class I mandibular dentition were supplied with prostheses in the posterior parts of the mandible. On one side they were given a prosthesis supported by two implants (prosthesis Type I) and on the other side they received a prosthesis supported by one implant and one natural tooth (prosthesis Type II). Sixty-nine fixtures were inserted and 46 prostheses constructed. Eight of the fixtures were lost during the observation period. The failure rate of the implants was about the same in the two types of prostheses; five fixtures belonged to prostheses Type I (10.9%) and two fixtures belonged to prostheses Type II (8.7%), while one fixture was lost prior to loading. From a theoretical point of view, the combination of a tooth and an osseointegrated implant should encounter problems with regard to the difference in bone anchorage and there should be a risk of biomechanical complications. However, the results of this study did not indicate any disadvantages in connecting teeth and implants in the same restoration.     

A 30‐Year Follow‐Up of a Patient with Mandibular Complete‐Arch Fixed Implant‐Supported Prosthesis on 4 Implants: A Clinical Report

Mandibular complete‐arch fixed implant‐supported prostheses are recognized as one of the earliest and most popular prostheses in implant dentistry. This prosthesis was the main focus in the early era of osseointegration. Despite its widespread popularity, few clinical reports have described long‐term follow‐up greater than 10 years for this type of prosthesis. This report describes a 30‐year follow‐up of a patient who underwent treatment for a mandibular complete‐arch fixed implant‐supported prosthesis with 4 machined surfaced implants, opposing a maxillary complete denture. This report documents a variety of photographs and radiographs taken over a period of 30 years to compare bone levels at various stages of care and maintenance, including de novo bone formation underneath the distal cantilevers due to functional loading. The biologic and biomechanical response to this treatment protocol and long‐term clinical observations and prosthodontic outcome and maintenance needs are also addressed.     

Within-subject comparison between connected and nonconnected tooth-to-implant fixed partial prostheses: up to 14-year follow-up study

PURPOSE: This long-term follow-up study aimed to compare the outcome of fixed prostheses supported by teeth and implants and by freestanding implants only. MATERIALS AND METHODS: From prosthesis insertion up to 14 years (mean 6.5 y), 18 patients were followed. Implant-supported prostheses with and without tooth connection were compared within the same jaw. The tooth-implant prostheses were supported by 30 implants and 30 teeth, and the freestanding prostheses were supported by 48 implants. Implant outcome, marginal bone stability, and mechanical complications were recorded. RESULTS: Neither implant mobility nor fractures of any component of the implants were observed. No prosthesis complications were observed, and the same applied for crown cement failure and intrusion of teeth. Only one periapical lesion was detected at the first follow up. The annual change of the marginal bone level around connected and freestanding implants did not differ significantly. The mean marginal bone loss (over the 2 groups) for the first 6 months amounted to 1.08 mm. After the first 6 months, an annual marginal bone loss of 0.015 mm was observed. There was no difference between the 3 connection types (single implant connected to single tooth, multiple implants and/or multiple teeth connected with single connector, and multiple connectors) for the first 6 months or thereafter. The marginal bone loss (over the 3 groups) for the first 6 months was 1.15 mm. After the first 6 months, the annual bone loss (over the 3 groups) amounted to 0.015 mm. CONCLUSION: Based on the results of this study, splinting teeth with implants for implant-supported fixed prostheses did not affect the long-term outcome in comparison to freestanding implants.     

An Alternative Technique for the Fabrication of a Metal‐Reinforced Interim Implant‐Supported Fixed Prosthesis: A Clinical Report

Despite advancements in restorative materials and techniques, complications with implant‐supported fixed prostheses such as veneer fracture and material wear are very common and present with varying frequencies. Following these complications, repair of this type of prosthesis can be time‐consuming and costly even in the hand of experience clinicians. Several techniques have proposed using the existing framework to minimize the cost of the repair for the patient; however, while the repairs are being performed, the patient will have to either wear an interim complete denture or no prosthesis, which might cause some inconvenience to the patient. This article will present a technique for the fabrication of a metal‐reinforced interim implant‐supported fixed prosthesis for patients to wear while the existing prosthesis is being repaired.     

种植固定义齿修复下颌磨牙游离端缺失的临床观察

目的:临床观察研究单纯种植体支持和天然牙与种植体联合支持修复下颌游离端缺失的效果。方法:20例患者采用种植体支持修复,共植入86枚种植体,和20例患者采用天然牙与种植体联合支持修复,共植入42枚种植体,完成对下颌游离端缺失的修复。结果:通过12—42个月的临床观察和X线检查。表现两种修复效果都好,种植体周围骨吸收均值为0.71mm/0.72mm。结论:种植体与天然牙可通过合理设计共同支持修复缺失牙。