Dental implants as strategic supplementary abutments for implant-tooth-supported telescopic crown-retained maxillary dentures: a retrospective follow-up study for up to 9 years

PURPOSE: The aim of this retrospective study was to present the results of implants and natural teeth used as combined abutments to support maxillary telescopic prostheses. MATERIALS AND METHODS: Between 1997 and 2004, 22 patients with residual maxillary teeth underwent prosthodontic rehabilitation with supplementary implant placement of implant-tooth-supported telescopic prostheses. A total of 60 supplementary implants (mean: 2.9 implants; SD: 1.6; range: 1 to 5 per patient) were placed in strategic position and connected with 48 natural abutment teeth (mean: 2.2 teeth; SD: 0.9; range: 1 to 4 per patient) using telescopic crowns. The follow-up registration included implant and natural tooth survival rates and peri-implant and periodontal parameters, along with prosthodontic maintenance. Natural tooth abutments were additionally followed to compare their periodontal parameters at baseline to the follow-up examination. RESULTS: After a mean of 38 months (12 to 108 months) no implants or natural tooth abutments were lost (survival rate: 100%). There was no fracture, endodontic treatment, loss, or intrusion of natural teeth used for telescopic abutments. Implant abutments showed high stability and excellent periimplant soft tissue conditions. Natural tooth abutments used for double crowns also showed uneventful progress. A low rate of prosthodontic maintenance was seen, with implant screw abutment loosening as the most severe complication (3 of 60 implants; 5%). CONCLUSIONS: On the basis of this retrospective clinical review, the following conclusions were drawn: (1) successful function over a prolonged period and a minor complication rate of implant-tooth-supported telescopic maxillary dentures may be anticipated, and (2) the great variety of treatment modalities offered by tooth-implant support for telescopic prostheses appears to be useful as a treatment option for the maxilla in elderly patients.     

Comparing bar and double-crown attachments in implant-retained prosthetic reconstruction: a follow-up investigation

Objectives: A removable implant‐retained dental prosthesis in an edentulous mandible can use telescopic crowns or a bar superstructure as anchorage elements for an overdenture. The aim of this study was to compare the clinical results for bar‐anchored and telescopic crown‐retained overdentures in implant prosthetic treatment of the toothless lower jaw with two or more implants placed in the intraforaminal region. Material and methods: A clinical and radiographical comparison was made of the telescope vs. the bar method for removable prosthetic rehabilitation treatments in patients with an edentulous mandible. For evaluation of the clinical data, the sulcus fluid flow rate, Periotest values, and the peri‐implant bone loss were recorded. Results: In the follow‐up examinations, 19 implant losses were reported between insertion and review of 328 implants. The frequency distribution of the observed loss rates showed no treatment‐specific trend. In the group with bar‐treated implants, failure led to ‘group loss’ of the whole prosthetic superstructure. Failure of one of the double‐crown‐stabilized full dental prosthesis could usually be adapted so that the overdenture remained usable even without re‐implantation. Conclusions: After comparing all the clinical parameters evaluated, no significant difference between the stabilization of full dentures via conus and telescopic crowns and bar‐anchored dentures could be found. The choice of one particular method remains the decision of the professional treating the patient.     

利用阻生智齿预备钛金属冠改善下颌义齿固位的应用观察

目的:利用阻生智齿增加下颌单颌总义齿固位力。方法:通过手术暴露下颌阻生智齿,在智齿冠上预备牙体,制作钛金属套冠将阻生齿牙冠形态转移至口腔中,从而把固位力不足的下颌单颌总义齿修复,转变成有正常基牙固位的可摘局部义齿修复。结果:通过3例利用埋伏阻生智齿接钛金属套冠,对下颌牙槽嵴严重吸患者的可摘局部义齿修复,经2～3年的临床观察,钛套冠固定良好,无松动,牙龈正常。可摘局部义齿固位良好。结论:利用埋伏阻生智齿接钛金属套冠,加强下颌牙槽嵴严重吸收可摘局部义齿固位力的效果明显。     

Implant‐Retained Removable Partial Dentures: An 8‐Year Retrospective Study

Purpose: To evaluate the long‐term outcomes of removable partial dentures (RPDs) retained (but not supported) by dental implants. Materials and Methods: We retrospectively evaluated 32 consecutive patients who received implant‐retained RPDs. Each patient received one to four endosseus implants; the sample included a total of 64 implants. Follow‐up was conducted for a minimum of 8 years, during which satisfaction, implant survival, and prosthetic success were evaluated. Results: Patient satisfaction systematically increased. The implant success rate was 93.75%, and 100% of the prostheses were successful. Conclusion: Implant‐retained RPDs are a reliable intermediate solution that can reduce biological and economic costs while maintaining implant treatment benefits and the ease of RPD procedures.     

Survival and complication rates of combined tooth-implant-supported fixed and removable partial dentures

PURPOSE: The aim of this study was to assess and compare clinical outcome results of tooth-implant-supported fixed and removable partial dentures in a selected population group of partially edentulous patients. Biological and technical complications were recorded and reviewed. MATERIALS AND METHODS: A retrospective analysis of the dental charts of 224 patients (174 men, 50 women) with a mean age of 51.3 years was carried out. The evaluation included details regarding the survival and technical complications of the prescribed prostheses, as well as the biological and technical complications associated with both types of abutments used, ie, teeth and implants. RESULTS: A total of 229 prostheses were supported by 459 implants and 449 teeth. They were monitored for a period of 2 to 10 years (median follow-up time: 6.7 years). At the end of the different observation periods, 14% of the tooth-implant-supported prostheses had undergone technical modifications, with no statistical difference in the occurrence of technical complications between the 2 types of prosthesis. Three of the functionally loaded implants were removed, while 23 abutment teeth were lost (15 had undergone endodontic treatment). Abutment teeth with a reduced attachment level after prosthesis insertion were significantly affected by biological complications (P = .04). CONCLUSIONS: The survival data for both types of prosthesis were comparable to prostheses supported solely by implants. There was no difference in the complication rate between primary splinting (fixed) and secondary splinting with telescopic systems (removable). A greater risk of biological complications was recorded for endodontically treated abutments or teeth with a reduced attachment level.     

Removable four implant-supported mandibular overdentures rigidly retained with telescopic crowns or milled bars: a 3-year prospective study

Purpose: The present study evaluated implant survival/success rate, peri‐implant parameters and prosthodontic maintenance efforts for four implant‐supported mandibular overdentures (IOD) rigidly retained on either milled bar or double crowns (telescopic) attachments. Material and methods: In a randomized prospective trial, 51 patients with edentulism received four mandibular interforaminal implants and complete maxillary dentures. For IOD, rigid denture stabilization was chosen randomly selecting 26 patients for milled bars (group I) and 25 patients for double (telescopic) crowns (group II). During a 3‐year follow‐up period, implant survival/success, peri‐implant parameters (marginal bone resorption, pocket depth, plaque‐, bleeding‐, gingival index [BI and GI], calculus) and prosthodontic maintenance efforts were evaluated and compared between both retention modalities used. Results: Forty‐five patients (23 group I, 22 group II) were available for a 3‐year follow‐up (dropout rate: 11.8%) presenting a high implant survival/success rate (100%). Peri‐implant marginal bone resorption, pocket depth as well as BI and GI did not differ for both rigid retention modalities. However, annually higher values for plaque‐ (NS) and calculus index (P<0.035) were noticed for the bar (group I) than for the telescopic crown (group II) attachments. Prevalence of prosthodontic maintenance did not differ between both retention modalities (group I: 0.41/maintenance efforts/year/patients vs. group II; 0.45 maintenance/efforts/year/patients). However, prosthodontic adaption for handling mechanism showed benefits for the bar retention. Conclusion: Rigid anchoring of IOD retained either by bar or telescopic attachments showed high implant success rates and minor prosthodontic maintenance efforts regardless of retention modalities used. Stable denture retention presented healthy peri‐implant structure for implants in bar and telescopic anchoring systems. Drawbacks such as higher plaque/calculus for bar retention and less favorable handling properties (output) for telescopic crown attachment leave the decision on the selection at the discretion of the clinician. To cite this article:
Krennmair G, Sütö D, Seemann R, Piehslinger E. Removable four implant‐supported mandibular overdentures rigidly retained with telescopic crowns or milled bars: a 3‐year prospective study.
Clin. Oral Impl. Res. 23 , 2012 481–488.
doi: 10.1111/j.1600‐0501.2011.02169.x     

Frictional telescopic crowns in severely reduced dentitions: a 5-year clinical outcome study

Clinical outcomes for frictional telescopic crowns supporting removable prostheses in patients with severely reduced dentitions with one to three remaining teeth per arch have been inadequately documented. Seventy-four patients with severely reduced dentitions received 82 telescopic removable partial dentures that were supported by 173 frictional telescopic crowns. The recorded individual telescopic abutment survival rate over a 60-month period was 80.6%. This observation was significantly influenced by sex and tooth vitality and mobility (Kaplan-Meier). The risk of loss of telescopic crowns was significantly influenced by sex, arch, vitality, and abutment tooth distribution (Cox regression). Telescopic removable partial dentures were proven to be a favorable treatment concept for severely reduced dentitions in the selected group of patients.     

Five‐year multicenter study of magnetic attachments used for natural overdenture abutments

The purpose of this study was to examine a longitudinal clinical performance of magnetic attachments used for natural overdenture abutments. The study included 131 patients who had used removable prostheses (complete overdentures 31%, partial dentures 69%) more than 5 years (40–90 years old) with 211 magnetic attachments on natural abutments (Magfit 400 or 600; Aichi Steel co., Aichi, Japan) treated in 15 clinics using a standardized protocol. Analyses were performed on the degree of patient satisfaction regarding retention, complications of magnets (corrosion, detachment from denture base), abutments (pain during mastication, periodontal pocket formation, inflammation, mobility), and dentures (fracture etc.). Ninety‐seven percent of patients were satisfied with the retention and stability of their dentures. No corrosion of magnet was observed, and 19 magnets were detached. Most frequent complication of abutments was periodontal pocket formation (52%), followed by the inflammation (29%), increase in mobility (27%) and pain (4%). Magnetic attachment on natural tooth abutments provided a viable and long‐term treatment option.     

Long-term analysis of telescopic crown retained removable partial dentures: survival and need for maintenance

OBJECTIVES: The aim of this retrospective longitudinal study was to evaluate the clinical long-term survival of telescopic crown retained removable partial dentures (TRPDs), the influencing factors on survival as well as the type and number of necessary treatments during the observation time. METHODS: The study is based on the data of 463 patients who had received a total of 554 TRPDs with a total of 1758 telescopic crowns between 1995 and 2004 in our Dental School. The influence of the patient's gender, location of the denture, number of abutment teeth per telescopic denture, their distribution (Kennedy-class) and the impact of a routinely follow-up programme on the survival probability were analysed. RESULTS: During the observation period (mean 5.3+/-2.9 years) 4.7% of the TRPDs ceased functioning and 3.8% of the abutment teeth were extracted. The survival probability after 5 years was 95.1% for the TRPDs and 95.3% for the abutment teeth. No denture with more than four abutments required replacement. Only the covariates number of abutment teeth and patient in-follow-up showed a significant (p<0.01) influence on the survival probability. 26.9% of the TRPDs needed facing repairs, 34.8% relines, 20.6% loss of cementation of a primary crown and 1% abutment tooth treatment. CONCLUSIONS: Within the limits of a retrospective study it can be concluded that the number of attachments and thorough aftercare have a considerable impact on the long-term success of TRPDs. Though loss of cementation and defects of the facings were significant in number, they did not endanger the long-term success of a TRPD at all.     

Complication and failure rates of fixed dental prostheses in patients treated for periodontal disease

Objectives: To evaluate the biological and technical complication rates of fixed dental prostheses (FDP) with end abutments or cantilever extensions on teeth (FDP‐tt/cFDP‐tt) on implants (FDP‐ii/cFDP‐ii) and tooth‐implant‐supported (FDP‐ti/cFDP‐ti) in patients treated for chronic periodontitis. Material and methods: From a cohort of 392 patients treated between 1978 and 2002 by graduate students, 199 were re‐examined in 2005. Of these, 84 patients had received ceramo‐metal FDPs (six groups). Results: At the re‐evaluation, the mean age of the patients was 62 years (36.2–83.4). One hundred and seventy‐five FDPs were seated (82 FDP‐tt, 9 FDP‐ii, 20 FDP‐ti, 39 cFDP‐tt, 15 cFDP‐ii, 10 cFDP‐ti). The mean observation time was 11.3 years; 21 FDPs were lost, and 46 technical and 50 biological complications occurred. Chances for the survival of the three groups of FDPs with end abutments were very high (risk for failure 2.8%, 0%, 5.6%). The probability to remain without complications and/or failure was 70.3%, 88.9% and 74.7% in FDPs with end abutments, but 49.8–25% only in FDPs with extensions at 10 years. Conclusions: In patients treated for chronic periodontitis and provided with ceramo‐metal FDPs, high survival rates, especially for FDPs with end abutments, can be expected. The incidence rates of any negative events were increased drastically in the three groups with extension cFDPs (tt, ii, ti). Strategic decisions in the choice of a particular FDP design and the choice of teeth/implants as abutments appear to influence the risks for complications to be expected with fixed reconstruction. If possible, extensions on tooth abutments should be avoided or used only after a cautious clinical evaluation of all options. To cite this article:
Brägger U, Hirt‐Steiner S, Schnell N, Schmidlin K, Salvi GE, Pjetursson B, Matuliene G, Zwahlen M, Lang NP. Complication and failure rates of fixed dental prostheses in patients treated for periodontal disease.
Clin. Oral Impl. Res. 22 , 2011; 70–77.
doi: 10.1111/j.1600‐0501.2010.02095.x     

套筒冠可摘活动义齿修复后出现的问题及处理

目的:探讨套筒冠可摘活动义齿修复后出现的问题与对策。方法:对7例套筒冠可摘活动义齿修复后出现的问题进行分析,并根据不同原因采取相应措施。结果:出现的问题包括内冠脱落、基牙折断、基牙牙龈炎或牙周炎复发、义齿固位力不够。内冠脱落是修复后出现的最常见问题。结论:为了减少套筒冠可摘活动义齿修复后的并发症,应严格遵循套筒冠可摘活动义齿的设计原则,临床操作要点和制作要求。     

Stress distribution of abutments and base displacement with precision attachment- and telescopic crown-retained removable partial dentures

Five types of removable partial dentures (two attachment dentures, two telescopic dentures and one clasp denture) were designed. The two attachment dentures were retained by the rigid-precision attachments with or without a stabilizing arm, and the two telescope dentures were retained with cone telescope crowns with or without cross-arch stabilization. The stresses acting on abutment teeth and denture bases and the movements of denture bases were investigated, and the influences of denture design were clarified. The stress acting on a terminal abutment tooth retained by a rigid-precision attachment or cone telescopic crown was larger than that acting on a terminal abutment tooth retained by a clasp. The attachment dentures tended to concentrate more stress at the terminal abutment tooth than did the telescopic dentures. The stress of denture base of an attachment denture and a telescopic denture was less than that of a clasp denture. There was no difference between the stresses of attachment and telescopic dentures. The displacement of the denture base tended to be less when the denture was designed with a rigid connection for the retainer and with cross-arch stabilization.     

联合卡环、延长卡环与套筒冠固位体的基牙位移实验研究

目的　探讨单侧游离端可摘局部义齿的不同固位装置对基牙的影响。方法　在上下牙列间放置食物片 ,应用单侧游离端缺失病例中使用最多的联合卡环、延长卡环和套筒冠作为固位装置。当咬合时 ,用高精度激光位移测量仪测得其基牙各自的位移量 ,进行分析比较。结果　 3种不同固位装置义齿的基牙 45都有牙体移动、倾斜、扭转及垂直向的位移。其位移量在水平扭转时 ,套筒冠为最小 (P <0 0 1 ) ;而垂直向的位移 ,套筒冠则大于联合卡环和延长卡环 (P <0 0 1 )。结论　与联合卡环和延长卡环相比较 ,套筒冠所承受的咬合压力接近牙轴方向并能使基牙力分散 ,受力均匀 ,有利于基牙的健康。     

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.     

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.     

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.     

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.     

Zirconia in fixed implant prosthodontics

Background: CAD/CAM technology in combination with zirconia ceramic has increasingly gained popularity in implant dentistry. Purpose: This narrative review presents the current knowledge on zirconia utilized as framework material for implant‐borne restorations and implant abutments, laboratory tests and developments, clinical performance, and possible future trends for implant dentistry are addressed. Material and Methods: A review of available literature from 1990 through 2010 was conducted with search terms zirconia,”“implants,”“abutment,”“crown,” and “fixed dental prosthesis” using electronic databases (PubMed) and manual searching. Results: Latest applications of zirconia in implant dentistry include implant abutments, multiple unit and full‐arch frameworks as well as custom‐made bars to support fixed and removable prostheses. High biocompatibility, low bacterial surface adhesion as well as favorable chemical properties of zirconia ceramics are reported. Zirconia stabilized with yttrium oxide exhibits high flexural strength and fracture toughness due to a transformation toughening mechanism. Preliminary clinical data confirmed the high stability of zirconia for abutments and as a framework material for implant borne crowns and fixed dental prostheses. Zirconia abutment or framework damage has rarely been encountered. However, veneering porcelain fractures are the most common technical complication in implant‐supported zirconia restorations. These porcelain veneer failures have led to concerns regarding differences in coefficient of thermal expansions between core and veneering porcelain and their respective processing techniques. Conclusion: As presently evidence of clinical long‐term data is missing, caution with regard to especially extensive implant‐borne zirconia frameworks is recommended.     

Replacement of missing teeth in a southern region of Vietnam — a descriptive dental laboratory study

Aim : To explore whether tooth replacement in a southern region of Vietnam is in line with the primary health care approach, aiming at health services for all people at affordable costs. Methods : Tooth replacement was investigated by means of prostheses as delivered by four dental laboratories of which the output was considered representative. Information was based on dental casts related to the prostheses. Results : Prostheses replaced almost all missing teeth, irrespective of the types (interrupted or shortened dental arches) and numbers of missing teeth in the dental arch they were made for. Acrylic removable partial dentures were the most common prostheses delivered (65% of removable partial dentures). Conclusion : It cannot be stated that dental arch conditions in this study were representative for the southern Vietnamese population. However, it is concluded that dental practitioners tend to provide complete dental arches by tooth replacements. This morphologically based approach might introduce over treatment. In line with primary oral health care, a functionally oriented treatment management, including the shortened dental arch concept, should be implemented.     

Failures and complications in patients with birth defects restored with fixed dental prostheses and single crowns on teeth and/or implants

Objectives: To assess retrospectively, over at least 5 years, the incidences of technical and biological complications and failures in young adult patients with birth defects affecting the formation of teeth. Material and methods: All insurance cases with a birth defect that had crowns and fixed dental prostheses (FDPs) inserted more than 5 years ago were contacted and asked to participate in a reexamination. Results: The median age of the patients was 19.3 years (range 16.6–24.7 years) when prosthetic treatment was initiated. Over the median observation period of 15.7 years (range 7.4–24.9 years) and considering the treatment needs at the reexamination, 19 out of 33 patients (58%) with reconstructions on teeth remained free from all failures or complications. From the patients with FDPs and single unit crowns (SCs) on implants followed over a median observation period of 8 years (range 4.6–15.3 years), eight out of 17% or 47% needed a retreatment or repair at some point due to a failure or a complication. From the three groups of patients, the cases with amelogenesis/dentinogenesis imperfecta demonstrated the highest failure and complication rates. In the cases with cleft lip, alveolus and palate (CLAP) or hypodontia/oligodontia, 71% of the SCs and 73% of the FDPs on teeth (FDP T) remained complication free over a median observation period of about 16 years. Sixty‐two percent of the SCs and 64% of the FDPs on implants remained complication free over 8 years. Complications occurred earlier with implant‐supported reconstructions. Conclusions: Because healthy, pristine teeth can be left unprepared, implant‐supported SCs and FDPs are the treatment choice in young adults with birth defects resulting in tooth agenesis and in whom the edentulous spaces cannot be closed by means of orthodontic therapy. However, the trend for earlier and more frequent complications with implant‐supported reconstructions in young adults, expecting many years of function with the reconstructions, has to be weighed against the benefits of keeping teeth unprepared. In cases with CLAP in which anatomical conditions render implant placement difficult and in which teeth adjacent to the cleft require esthetic corrections, the conventional FDP T still remains the treatment of choice.