A Technique for Retrofitting a Metal Ceramic Crown to an Attachment‐Retained Removable Partial Denture: A Clinical Report

In dental applications, precision attachments have been used to retain removable partial dentures (RPDs) for several decades. Various types of extracoronal attachments are commonly used in combination with fixed partial dentures and RPDs to achieve retention and stability. Fracture of the framework, fracture of the roots or teeth, and irretrievable decrease of retention are common reasons for a failed attachment‐retained RPD. Another complication of metal ceramic crowns with precision attachment is decementation of the crowns. When fixed components of the attachment‐retained RPD fail, the traditional treatment approach requires remaking both the fixed and removable components of the attachment‐retained RPD. This technique describes retrofitting of a metal ceramic crown to a resilient attachment‐retained RPD.     

In vitro investigation of various attachments for overdentures on osseointegrated implants

summary Primary splinting of fixtures with bar attachments has proved to be clinically effective for overdentures on osseointegrated implants in the edentulous mandible. However, in vitro investigations indicate that a more favourable force transfer to the individual fixtures can be attained by secondary splinting of four implants with conical double crowns. This observation could be confirmed in the present study by measurement of implant deflection in a model of the mandible by means of interferometric optical holography. Telescope crowns with conical interface brought about functionally more even movement characteristics of the implants compared to rigid or jointed bar attachments. Moreover, the conical double crowns always ensured a stable position of the denture in contrast to jointed attachments. These results underscore the need to test conical double crowns clinically as anchors for overdentures on osseointegrated implants.     

Combined prosthodontic and orthodontic treatment of a patient with a Class III skeletal malocclusion: a clinical report

This clinical report describes a multidisciplinary approach for the treatment of a patient with Angle Class III skeletal malocclusion and decreased occlusal vertical dimension. An overlay removable partial denture (ORPD) was used to reestablish the occlusal vertical dimension (OVD). After the trial and adjustment period, the reduced lower anterior dentofacial height was orthodontically increased and the negative horizontal overlap was corrected. A maxillary precision attachment RPD and a mandibular fixed partial denture and metal ceramic crowns were fabricated to satisfy esthetic and functional requirements.     

Implant-supported mandibular overdentures retained with ball or telescopic crown attachments: a 3-year prospective study

PURPOSE: The aim of the present study was to evaluate implant survival, peri-implant conditions, and prosthodontic maintenance requirements for implant-supported mandibular overdentures in atrophic mandibles retained with ball or resilient telescopic crown attachments during a 3-year period. MATERIALS AND METHODS: Twenty-five patients with edentulous mandibles each received 2 Camlog root-form dental implants in the mandibular interforaminal (canine) region. The denture attachment system was chosen randomly; 13 patients received ball attachments and 12 patients received resilient telescopic crowns. Implant survival, implant mobility (Periotest values), and peri-implant conditions such as bone resorption, pocket depth, Plaque Index, Gingiva Index, Bleeding Index, and Calculus Index values were assessed for each implant. In addition, detailed prosthodontic maintenance was evaluated during the follow-up period and the 2 retention modalities were compared. RESULTS: There were no differences in implant survival, implant mobility (Periotest values), and peri-implant conditions between the 2 retention modalities. During the 3-year period significantly more complications/interventions for maintenance purposes were registered in the ball group (62 interventions) than in the telescopic crown group (26 interventions; P < .01). CONCLUSION: The results indicate that both ball attachments and resilient telescopic crowns used on isolated implants in the edentulous mandible are viable treatment options. Implant success and peri-implant conditions did not differ between ball attachments and telescopic crowns used as retention modalities for implant overdentures, but the frequency of technical complications was significantly higher with ball attachments than with resilient telescopic crowns.     

插销式附着体的临床应用

目的 探讨插销式附着体在双侧远中游离端局部活动义齿中的固位和稳定性。方法 制作带有插销式附着体底座的基底冠,并通过平行研磨仪确定附着体的工仙就位道。结果 以插销式附着体为固位体的双侧远中游离端局部活动义齿的固定和稳定性高于普通三臂卡环为固位体的义齿。结论 插销式附着体是一种结构简单,固位和稳定性较好的固位体。值得临床推广应用。     

Telescopic crowns as attachments for implant supported restorations: a case series

The use of dental implants to support mandibular or maxillary overdentures is a widely used treatment modality. Advantages are an increase in retention, an increase in chewing ability, and easy access for oral hygiene procedures. While telescopic and conical crowns have been used for decades to connect natural teeth to overdentures, not many cases have been reported in the literature of telescopic crowns placed on implants to support overdentures. This article describes 7 patients with overdentures supported by telescopic crowns who received 65 implants (ITI Straumann). The cases presented in this report have been in function for up to 4.5 years. During that time no adverse events were reported. The use of telescopic crowns as attachments for implant-supported overdentures may be a viable treatment option.     

Retention force changes in implant-supported titanium telescope crowns over long-term use in vitro

summary Titanium is used to fabricate spherical and bar attachments for overdentures on osseointegrated implants. This in vitro study investigated the long term effects of commercially pure titanium on the retention force of telescope crowns with conical interface. Combinations of various materials for the inner and outer crowns were tested. Telescope crowns of pure titanium showed retention force charac teristics comparable to telescope crowns fabricated conventionally in a precious alloy.     

Prosthodontic rehabilitation of dental implants with exposed threads: a clinical report

An unconventional technique was used to address the challenge of exposed dental implant threads. Titanium dental implants were prepared with rotary instruments to eliminate the exposed threads and to receive a fixed cementable prosthesis. The technique required fabrication of a gold casting of 2 copings connected by a round bar to fit the prepared implants and an implant-retained overdenture. This technique may be applied to other situations when multiple implants present with thread exposure and bone resorption. These include single crowns, partial fixed dental prostheses, and attachments for overdentures.     

Maxillary Rehabilitation Using Fixed and Removable Partial Dentures with Attachments: A Clinical Report

Despite requiring dental crown preparation and possible root canal treatment, besides the difficulty of clinical and laboratory repairs, and financial burden, the association between fixed (FPD) and removable partial dentures (RPD) by means of attachments is an important alternative for oral rehabilitation, particularly when the use of dental implants and FPDs is limited or not indicated. Among the advantages of attachment‐retained RPDs are the improvements in esthetics and biomechanics, as well as correction of the buccal arrangement of anterior teeth in Kennedy Class III partially edentulous arches. This article describes the treatment sequence and technique for the use of attachments in therapy combining FPD/RPD.     

(Semi-)precision attachments for cast metal frame removable partial dentures

When compared to a conventional attachment, a (semi)precision attachment for a cast metal frame removable partial denture can perform a number of functions better. Proper assessment of the condition of the abutment teeth is needed for an adequate indication. Selecting the type of (semi-)precision attachment is primarily determined by the available maxillomandibular space, the crown length as well as the possibility of adequate oral self-care. With regard to technical characteristics, (semi-)precision attachments are classified according to measures of freedom. The distinct types are cast intra- and extra-coronal, adhesive and overdenture (semi-)precision attachments. With the lapse of time, some wear of the different parts of an attachment may occur, requiring specific subsequent care. Whether or not in combination with oral implants, (semi-)precision attachments often offer patients improved self-confidence and self-image. However, the relatively high cost is a barrier to apply (semi-)precision attachments widely.     

Technical failure rates of double crown-retained removable partial dentures

Removable partial dentures (RPD) can be retained using conical crowns or parallel-sided telescopic double crowns. The purpose of this study was to evaluate and compare the technical failure rate of the two retainer systems. One hundred seventeen dentures made by dentists of the medical school were included. Seventy-four RPD were retained with parallel-sided crowns (n=251) and 43 with conical crowns (n=160). Following the medical report follow-ups from January 1992 to December 1998, technical RPD failures were noted and analyzed. Technical problems occurred during the observation time in 48.8% of the conical retained dentures and 34.2% of the parallel-sided retained dentures. In both cases, loss of cementation was most frequently noted, while loss of the facings occurred only with conical crowns. Other technical failures did not depend on the type of retainer system used. These were most frequently problems with the denture base, e.g., fracture of artificial teeth or the metal framework. We conclude that there were different technical failures of both double crown retainer systems. These problems were not insignificant in number but treatable. Received: 14 December 1999 / Accepted: 19 January 2000     

All-ceramic surveyed crowns for removable partial denture abutments

All-ceramic restorations may have limitations when used in combinations with other treatment modalities. Removable partial denture (RPD) abutment crowns are typically shaped to provide guide planes, rest seats, and retentive areas. Porcelain-to-metal crowns are routinely fabricated with retentive contours in the veneering porcelain, but until recently, the contours of the other portions of the restoration were developed in metal. This article describes the fabrication of all-ceramic crowns for RPDs with rest seats and guide planes in densely sintered aluminum oxide and retentive areas in veneering porcelain. Within the limitations outlined, this procedure allows the practitioner to use all-ceramic crowns in situations previously reserved for metal or metal-ceramic restorations.     

Effect of implant support on distal extension removable partial dentures: in vitro assessment

The implants in implant-supported removable partial dentures (RPDs) are placed in the edentulous ridge to stabilize the RPD and minimize the resultant rotational movement. This study investigated the effect of implant placement on RPD stability. A model simulating a mandibular bilateral distal extension missing was fabricated using epoxy resin and silicone impression material as thin (1 mm) and thick (2 mm) soft tissues. Five pressure sensors (PS-10K, Kyowa, Tokyo, Japan) were attached near the left and right first molars (#36 and #46), first premolars (#34 and #44) and medio-lingual alveolar crest. Five bilateral distal extension RPDs with Co-Cr frameworks were conventionally fabricated. After the implants were placed at the bilateral second molar areas, healing caps (4.5 mm high) were connected to the denture base with autopolymerized resin to support the RPD. As in a conventional RPD, sealing screws were placed without connecting them. Loads up to 5 kg were applied, and the pressure and displacement of the RPDs (n = 5) were simultaneously measured and analysed using the Wilcoxen test (alpha = 0.05). There was less pressure on both thin and thick soft tissues, the #36, #46 and the medio-lingual alveolar crest from the implant-supported RPD than from the conventional RPD (P < 0.05). There were no significant differences in pressure on #34 and #44 between the two RPDs (P > 0.05). There was significantly less denture displacement of the implant-supported RPD than of the conventional denture (P < 0.05). Implant support helped prevent the displacement of distal extension RPDs and decreased the pressure on soft tissues.     

Oral mucosa pressure caused by mandibular implant overdenture with different types of attachments

PurposeTo determine the appropriate attachment and design of a denture base for mandibular implant overdenture (IOD), the oral mucosa pressure caused by mandibular implant overdentures was measured using edentulous jaw models with various attachments.MethodsAn experimental edentulous mandibular model with a 1.5-mm thick artificial oral mucosa was used. Two implants were placed at the area equivalent to the bilateral canines of an experimental jaw model. Locator attachments (LA), ball attachments (BA), magnetic attachments (MA), and round-bar attachments (R-BA) were fabricated. Six miniature pressure sensors were placed at the bilateral buccal premolar regions, bilateral buccal shelves, and bilateral lingual molar regions. A precision universal testing machine was used to apply dynamic repetitive loads of 50 N. The load points were the center of the model, which should represent bilateral mastication on both sides (bilateral load), and were equivalent to the left first molar, which should represent unilateral mastication (unilateral load). Statistical analysis was performed using one-way analysis of variance. Multiple comparisons were then performed using the Bonferroni post hoc test. P < 0.05 was considered statistically significant.ResultsUnder the bilateral load condition, the lower oral mucosa pressure value with BA was measured, compared to other attachments at all measurement sites. Under the unilateral load condition, the oral mucosa pressure value of BA was smaller than the other attachments at the measurement site on the loading side.ConclusionsBA has exerted the greatest effects on support and bracing, suggesting that, BA is suitable for reducing oral mucosa pressure during mastication.     

键槽缓压式与按扣式附着体义齿的临床应用

目的：评价2种冠外精密附着体义齿修复牙列缺损的临床效果。方法：采用键槽缓压式（ACS－52）附着体13副，按扣式Revax system附着体10副，分别修复14例牙列缺损患。其中肯氏I类缺损3例，肯氏Ⅱ类缺损6例，肯氏Ⅲ类缺损5例。对临床修复效果进行分析，并与同期进行的，同类别缺损的RPD对照。结果：经6个月－5年观察，85％以上患认为附着体义齿美观，舒适，稳固，易适应，咀嚼有力。对74颗基牙复查结果显示，基牙无叩痛，松动，无根尖周病变及牙槽骨吸收，其中16颗基牙有龄缘充血水肿现象，附着体上少量牙石沉积；对照组56颗基牙中24颗（42．86％）有龋缘充血水肿，其中12颗（21．42％）甚至有颈部继发龋发生。所有修复患嚼效能测定：PAD组6个月后的咀嚼效能可达同龄正常牙列的82．40％，5年后达正常牙列的93．30％；RPD组6个月后达53．90％，5年后达71．90％，P＜0．05。结论：冠外精密附着体义齿能达到良好的修复效果。     

球帽式与套筒冠式下颌种植覆盖义齿的三维有限元分析

目的:应用三维有限元分析,比较球帽式和套筒冠式附着体对下颌种植覆盖义齿的应力分布的影响。方法:本实验应用三维有限元法分析,模拟下颌覆盖义齿在正中咬合状态下的受力情形。结果:两种模型中,骨组织界面应力主要都集中在种植体颈部周围的皮质骨中。球帽式附着体模型中牙槽嵴表面上的最大压应力峰值为-1.601Mpa,而套筒冠式附着体模型的压应力峰值为-0.296Mpa。套筒冠式附着体模型的中央种植体、侧方种植体上的应力峰值均小于球帽式附着体的种植体。结论:套筒冠式覆盖义齿较球帽式可降低种植体及剩余牙槽骨表面的应力,更有助于保存牙槽骨组织和种植体。     

Maxillary removable prostheses retained by telescopic crowns on two implants or two canines

Precision telescopic attachments allow for rigid connection between removable prostheses and abutments. However, it is still unknown whether implants can bear similar long-term loading forces as teeth when telescopic crowns are used as retention devices. It was the aim of this prospective clinical study to observe maxillary removable partial dentures that were retained by telescopic crowns on two endosseous implants in the canine regions. In a control group, identical dentures were fabricated that were retained by telescopic crowns on the maxillary canines. The implant group consisted of 14 patients, and the control group included 8 patients. Mean observation time of the prostheses was 25.6 months. Radiographic bone levels and periodontal parameters did not reveal specific differences between the two groups. However, five implants failed, and there were no failures in the control group. Survival rates were 48.9% for the implant group and 100% for the control group, with a significant difference between the two groups. Within the limits of this study, it is concluded that the telescopic connection might be too rigid (thus delivering overloading) for two single implants in the canine region of the maxilla supporting a removable denture.     

An evaluation of crowns and bridges in a general dental practice

In this article the results are presented of an evaluation of crowns and bridges in a general practice. The study includes 601 solitary crowns, 213 crowns on bridge abutments and 103 crowns on RPD abutments. In total eighty-four bridges were examined. All these restorations were constructed during a period of 11.5 years. By means of the Kaplan-Meier method a prognosis is given of the life span of the different solitary crown-types over periods between 1 and 11 years. The total amount of failures and follow-up treatments on bridge and RPD abutments was very small. The authors also examined whether the bridges were constructed according Ante's law. A follow-up of this study in other Dutch general practices in combination with experimental clinical trials is under way.     

Maxillary Rehabilitation Using a Removable Partial Denture with Attachments in a Cleft Lip and Palate Patient: A Clinical Report

Clefts of the lip and/or palate (CLP) are oral‐facial defects that affect health and overall quality of life. CLP patients often need multidisciplinary treatment to restore oral function and esthetics. This paper describes the oral rehabilitation of a CLP adult patient who had maxillary bone and tooth loss, resulting in decreased occlusal vertical dimension. Functional and cosmetic rehabilitation was achieved using a maxillary removable partial denture (RPD) attached to telescopic crowns. Attachment‐retained RPDs may be a cost‐effective alternative for oral rehabilitation in challenging cases with substantial loss of oral tissues, especially when treatment with fixed dental prostheses and/or dental implants is not possible.     

Precision attachment-retained removable partial dentures. Part 3. General practitioner results up to 2 years

PURPOSE: The aim of this study was to analyze the techniques, production problems, and 2-year results of attachment-retained removable partial denture (RPD) treatment provided by general practitioners in Sweden. MATERIALS AND METHODS: At a major dental laboratory, consecutive cases involving new production of crowns, or of fixed partial dentures (FPDs) and RPDs retained with precision attachments, were studied. Parameters of the dentition, crown or FPD, type and brand of attachment, etc, as well as early satisfaction by dentist and patient, were recorded using specially designed forms at the dental laboratory and questionnaires for the dentists. After 2 years, questionnaires were again sent out to the dentists to record complications and patients' and dentists' opinions of the results. The sample gathered totaled 83 constructions. After 2 years, responses for 57 patients, all of whom had distal-extension RPDs, were received. Most drop-outs in the study were explicable. RESULTS: The most frequently cited reasons for using attachments were esthetics and need for crowning the teeth abutting the RPD. McCollum rigid slide attachment was the predominant brand used (43% of constructions). Dentists and patients were dissatisfied with 6% of the constructions. During the first 2 years, 22 of 57 constructions were complication-free. Seventeen had attachment complications and 9 had serious complications related to the abutment teeth or RPDs. A comparison between these 2 groups revealed that those with complications had every second abutment root-canal treated and a root post, while the group without complications had every fifth abutment root-canal treated. CONCLUSION: There were many technical and biotechnical complications and failures; the exact ratio, however, depended on the definition of "complications" and "failure." The 2-year results also deviated considerably from the dentists' opinions of the early results.