Retrofitting a dowel and core to an existing crown.
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Cementation↗
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Results for “Prosthesis Retention”
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Cement-retained versus screw-retained implant restorations: achieving optimal occlusion and esthetics in implant dentistry.
STATEMENT OF PROBLEM: Optimal occlusion and esthetics are goals in prosthetic treatment. Implant dentistry is no exception. PURPOSE OF ARTICLE: The purpose of this article is to discuss how the choice to use screw-retained or cement-retained implants dramatically influences the occlusion and esthetics.
Cementation↗
Necessary modification of the nonrotational tapered impression coping of the EsthetiCone system.
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Crowns↗
Effects of adhesive fixed prosthesis retainer design on resultant resin luting agent thickness.
STATEMENT OF PROBLEM: Resin cement thickness may influence the success or otherwise of adhesive fixed prostheses and needs to be quantified for future stress analyses. PURPOSE: This study evaluated the effect of different complexities of retainer preparation design on resultant resin lute thickness. MATERIAL AND METHODS: Five retainer designs were evaluated for resin luting thickness (Panavia Ex) after cementation to appropriately selected natural teeth as follows: (1) flat plate retainer; mandibular canine; (2) occlusal rests, mandibular premolar; (3) occlusal rests, proximal grooves, mandibular premolar; (4) modified three-quarter crown, mandibular premolar; and (5) occlusal strut, maxillary premolar. Five samples of each design were prepared in vitro. A mesiodistal and a buccolingual section were obtained from each sample with a diamond saw. Measurements were carried out on the fluorescent cement lute with a confocal microscope. Mean resin thickness and cervical resin thickness were analyzed with analysis of variance and Tukey tests. RESULTS: Resin thickness (micron) for each of the retainer designs were as follows (mean +/- SD): design 1, 58 +/- 40; design 2, 67 +/- 42; design 3, 80 +/- 28; design 4, 87 +/- 15; and design 5, 85 +/- 29. There were no significant differences among the designs (mean global value 75.4). The three-quarter crown (design 4) had a significantly wider cervical resin thickness (P < or = .01) than designs 1, 2, and 3.
Analysis of Variance↗
A new gingival retraction impression system for a one-stage root-form implant.
Displacement of soft tissue adjacent to an implant abutment is arduous. Currently, gingival retraction cord is used before making an impression for cement-retained implant restoration. This article presents a new impression system for a cementable abutment/implant. The advantages of a cement-retained implant crown are described. This system provides efficient and accurate impressions.
Cementation↗
Use of the fixed mandibular implant in oral cancer patients: a retrospective study.
PURPOSE: A retrospective review of the fixed mandibular implant (FMI) in oral cancer patients is presented. Success of the device and associated complications are discussed. PATIENTS AND METHODS: Eighteen oral cancer patients with an FMI were identified. All were treated at a single institution. Information was obtained from medical records, radiographs, and recall examination. Demographic data, surgical history, prosthesis design, and functional data were analyzed. Results were statistically compared with outcome data for the FMI in noncancer controls. RESULTS: The average patient age was 64 years. Seventeen of the 18 patients had squamous cell carcinoma, most being T3 or T4 lesions at diagnosis. Four of 18 patients received radiation therapy (XRT) followed by resection, 11 had resection followed by XRT, two had XRT alone, and one had surgery alone. The average XRT dose to the mandible was 65.4 Gy. Two of the patients received hyperbaric oxygen (HBO). Sixteen of the implants had been loaded and followed an average of 16.4 months. Early complications included soft tissue overgrowth around pins (4 of 18); tongue ulceration (2 of 18), and intraoral wound dehiscence (2 of 18). Late complications included fistula formation (3 of 18); submental erythema (2 of 18), and persistent tissue overgrowth around pins (1 of 19). No complications required removal of the implant. Only the rate of fistula formation was statistically greater than in controls (P = .005). Average time between FMI placement and prosthesis delivery was 3.6 months. Fourteen of the 16 patients with a prosthesis reported improved ability to eat solid foods and improved articulation. All 16 patients reported improved aesthetics and increased comfort in social settings. CONCLUSIONS: The FMI is a valuable device for dental rehabilitation in oral cancer patients. Success was shown in radiated patients. The complication rate is acceptable, and stability was shown over the follow-up period. Rapid rehabilitation and functional and aesthetic improvements were also reported.
Aged↗
Reconstruction of residual alveolar cleft defects with one-stage mandibular bone grafts and osseointegrated implants.
PURPOSE: This study evaluates a treatment regimen for reconstruction of residual maxillary alveolar cleft defects consisting of mandibular bone grafting and immediate implant installation. PATIENTS AND METHODS: Sixteen cleft patients (five female and 11 male) had residual cleft defects of the alveolar ridge reconstructed with bone grafts from the mandibular symphyseal region. The bone graft was pretapped at the donor site before fixation in the residual ridge with Brånemark implants. Twenty implants were installed according to this concept. The period of observation ranged from 36 to 69 months, with a mean of 48 months after implant installation. RESULTS: Five patients developed wound dehiscenses that resulted in total or partial bone graft sequestration. Two implants were lost, one due to sequestration and the other due to mobility at the abutment procedure; 18 implants were still well functioning at the end of the observation period. However, all patients showed significant periimplant bone resorption after this one-stage treatment. CONCLUSION: Because of the observed complication rate, the one-stage procedure may not be optimal for reconstructing residual cleft defects.
Adolescent↗
Qualitative evaluation of elderly home residents' fixed and removable prostheses in relation to the ADL index.
UNLABELLED: Functional diversity and biopsychosocial state is a significant issue, which greatly influences elderly oral health and state of fixed and removable prostheses. OBJECTIVES: The goal of the investigation was to evaluate the quality of fixed and removable prostheses in a group of elderly home residents in relation to the ADL index. METHODS: The group consisted of 175 institutionalised elderly, mean age 76.8 years. Special care need was assessed on ADL scale. To evaluate the quality and need for replacement of fixed and removable prostheses Karlsson's and modified Nevalainen et al. indices were used. RESULTS: Spearman's correlation analysis showed significant correlation of ADL index scores and both Karlsson's index values (rho=-0.468, p<0.01) as well as for modified Nevalainen's indices (rho=-0.572, p<0.01). Lower ADL score was correlated with poorer oral hygiene and condition of fixed or removable dentures. It was determined that 87% of the examined patients were in objective need of fixed, removable or combined prosthodontic treatment. CONCLUSIONS: The study showed that lower ADL index scores of functionally dependent elderly patients correlate with poorer condition of fixed and removable prostheses and greater need of fixed, removable or combined prosthodontic treatment.
Activities of Daily Living↗
Reactions of peri-implant tissues to continuous loading of osseointegrated implants.
Functional and morphologic reactions of peri-implant bone surrounding screw implants (Bonefit) were studied in three dogs by loading the implants with continuous forces of 2 (about 204 gm) and 5 N (about 510 gm). Eight implants were inserted to an endosseous length of 12 mm and placed about 10 mm apart in the region of the lower premolars. The fixtures healed in a closed environment for 12 weeks, after which they were uncovered and loaded with abutments and orthodontic devices to produce horizontal distraction with a force of 2 N (about 204 gm) for 12 weeks. Subsequently they were loaded with 5 N (about 510 gm) for another 24 weeks. The distance between and the mobility of the implants were determined before and after each phase of experimental loading. Fixtures of the same type that were osseointegrated and not exposed, or osseointegrated and loaded by mastication, were used as a control. Animals were euthanized and specimens sectioned. The result was that continuously loaded implants showed no significant displacement for any force level. The mobility of the fixtures increased slightly by about 1 Periotest-value (PTV) at the end of the experiment. No significant peri-implant pocket could be seen in implants loaded by continuous or masticatory forces. Histologic and morphometric evaluation indicated compaction of bone as a result of loading. Osseointegrated implants have potential as a firm osseous anchorage for orthodontic treatment and can resist continuous horizontal forces of at least 5 N (about 510 gm) during a period of several months.
Absorptiometry, Photon↗
A new removable implant analog.
A new implant analog system that improves the efficiency of the implant restoration's fabrication process is described. This 2-piece analog contains an outer plastic sleeve that is retained within the stone cast. The inner portion, a metal analog, can be easily removed and replaced within the plastic sleeve. Because the metal analog is removable, the time-consuming process of screwing and unscrewing the prosthesis- or abutment-retaining screws during laboratory procedures can be minimized. The prosthesis can remain secured to the analog during waxing, metal finishing, and porcelain buildup, yet is easily removed from the cast for inspection.
Crowns↗
Tissue integration of non-submerged implants. 1-year results of a prospective study with 100 ITI hollow-cylinder and hollow-screw implants.
It has been postulated that the wound healing in a closed submerged location is one of the prerequisites for osseointegration of dental implants. The purpose of the present study was to evaluate the tissue integration of intentionally non-submerged titanium implants inserted by a one-stage surgical procedure. 100 ITI implants were consecutively placed in 70 partially edentulous patients. After a healing period free of masticatory loading for at least 3 months, the implants were examined. The clinical status showed for all implants neither detectable mobility nor signs of a peri-implant infection. Therefore, prosthetic abutments were inserted, and the patients were restored with fixed partial dentures. All patients were regularly recalled at 3-month intervals, and no patient dropped out of the study. Thus, all 100 implants were re-evaluated 12 months following implantation. Plaque- and sulcus bleeding indices, probing depth, clinical attachment level, width of keratinized mucosa, and periotest scores were assessed. In addition, standardized radiographs were analyzed for the presence of peri-implant radiolucencies and for the location of alveolar bone levels around the implants. Based on predefined criteria, the implants were classified as successful or failing. 98 implants were considered successful, and 1 implant failing. The remaining implant exhibited a peri-implant infection requiring local and systemic antimicrobial treatment. The results of this short-term study indicate that intentionally non-submerged ITI implants yield a high predictability for successful tissue integration.
Dental Implants↗
ITI implants in combination with bone grafts: design and biomechanical aspects.
In this article we describe the implantation of ITI implants in combination with bone grafts. Two different cases were considered: the augmentation of an atrophic maxilla or mandible where the transplant was fixed by means of ITI implants and the implantation into free transplants fixed by means of the THORP reconstruction plate system. These indications require 2-stage procedures with submerged implants and transplants during the healing period. For this new applications, standard ITI implants were combined with specially developed new transgingival units of high manufacturing precision. The new design resulted in a maximum tightening moment of 4.0 N.m versus 1.25 N.m achievable with a conventional 2-mm screw. Dynamic testing showed that, for the range of tightening moments of 0.25 N.m up to 1.0 N.m, the loosening moment after 2,000,000 cycles remained approximately 10% above the tightening moment. For the clinical application a tightening moment of 0.35-0.5 N.m is recommended. The special design and the high precision of the extension parts results in a tight adaptation between the primary implant and the extension parts, which may be important for microbiological reasons.
Alveolar Ridge Augmentation↗
Non-submerged osseointegrated dental implants with ball attachments supporting overdentures in patients with mandibular alveolar ridge atrophy. A short-term follow-up.
Non-submerged, hollow screw ITI-Bonefit dental implants with ball attachments supporting overdentures were used as alternative treatment to combined vestibulo-lingual-plasty with free split-thickness skin graft and removable dentures in 40 consecutive patients with mandibular alveolar ridge atrophy. One hundred and fifty-six non-sub-merged fixtures were installed. Ball attachments were mounted on the fixtures and implant-supported overdentures inserted 3-4 months after fixture installation. The observation period after implant activation and prosthesis insertion varied from 1 to 3 years with a median observation period of 2 years. The overall success rate of individual implants was 99%(155/156). The prosthesis function rate was 100%(40/40). The 1-year success rate of individual implants was 99%(155/156) with a prosthesis function rate of 100%(40/40). No persistent surgical, periodontic or prosthodontic complications were observed. The results indicate that non-submerged osseointegrated ITI-Bonefit dental implants with ball attachments supporting overdentures can be a successful alternative to combined vestibulo-lingual-plasty with free split-thickness skin graft and removable dentures, and as successful as the use of submerged dental implants.
Aged↗
Resonance frequency measurements of implant stability in vivo. A cross-sectional and longitudinal study of resonance frequency measurements on implants in the edentulous and partially dentate maxilla.
The aim of this investigation was to evaluate the use of resonance frequency measurements in the clinical measurement of implant stability. Resonance frequency measurements are undertaken by measuring the response of a small transducer attached to an implant fixture or abutment. Two groups of patients were selected for study. Group A comprised 9 patients who had a total of 56 implants placed. Resonance frequency measurements were made at fixture installation and repeated 8 months later at abutment connection. The resonance frequency of the implant/transducer system increased for 50 out of the 56 implants from a mean value of 7473 Hz +/- 127 Hz (P < 0.05) to a mean of 7915 Hz +/- 112 Hz (P < 0.05). Two implants had failed to integrate and the resonance frequency of these had fallen. Group B comprised 9 patients who had been provided with fixed prostheses and had a total of 52 implants placed. They were examined 5 years after fixture placement and the prostheses removed. All implants were judged clinically to be osseointegrated. The level of the marginal bone around each implant was calculated by measuring the number of exposed threads on intraoral periapical radiographs and added to the length of each abutment to give a value termed the effective implant length (EIL). Measurements indicated a correlation (R = -0.78, P < 0.01) between EIL and resonance frequency. The results support the hypothesis that the resonance frequency of an implant/transducer system is related to the height of the implant not surrounded by bone and the stability of the implant/tissue interface as determined by the absence of clinical mobility.
Aged↗
Immunohistochemistry of soft tissues surrounding late failures of Brånemark implants.
The objective of the present investigation was to characterize the cellular composition of the soft tissues surrounding consecutively retrieved late failures of Brånemark implants. Criteria for implant failure were signs of loss of osseointegration (radiographic peri-fixtural radiolucency and mobility). The clinical history of the implants did not include adverse symptoms. At the time of retrieval, percussion-induced pain was experienced at 4/8 implants, but no macroscopical signs of inflammation or infection or infection was observed. Immunohistochemistry was applied on 6 marginal peri-implant specimens and on specimens of deeper tissues associated with the previously load-bearing implant surface from 8 failed implants, whereas 6 clinically healthy mucosal specimens and 4 hyperplastic biopsies from stable implants served as controls. The immunohistochemical evaluation showed that the soft tissues surrounding failed implants contained a large number of macrophages (CD68), HLA-DR positive cells, lymphocytes and plasma cells preferentially accumulated towards the removed implant surface. PMNs were a rare finding. Downgrowth of epithelium, in some cases encapsulating the whole fixture, was observed in sections where an intact implant/soft tissue interface was preserved. Healthy control mucosal specimens always contained labelled cells, albeit in a low amount, whereas hyperplastic control samples displayed an intense inflammatory and immunological response with numerous positive cells and PMNs scattered throughout the biopsy. In conclusion, failed implants were characterized by a chronic inflammatory response of the surrounding tissues with macrophages as the predominant labelled cell type, while hyperplastic tissues around stable implants were distinguished by an acute inflammatory process. These findings suggest that an on-going infection is unlikely to be the etiological factor for the late failures of dental implants examined in this study.
Aged↗
Peri-implant microflora of implants with cemented and screw retained suprastructures.
The aims of this study were to compare clinical and microbiological features in the peri-implant area of implants carrying either screw retained or cemented suprastructures, and to investigate the relationship between the peri-implant microflora, the microbiota on the inner surface of removable suprastructures, and the periodontal microflora within the same subject. In 15 partially edentulous patients with ITI implants used as abutments for crown and bridge reconstructions, microbial samples were taken i) from the deepest periodontal pocket of each quadrant, ii) from the sulcus of the implants and iii) from the internal surface of the screw retained suprastructures. The samples were cultured using continuous anaerobic techniques. Five patients were found with both screw retained (S) and cemented (C) suprastructures. In these subjects the mean total cultivable counts were significantly higher in peri-implant samples from group C than in samples from group S. Furthermore, peri-implant samples of group S yielded a higher proportion of coccoid cells in the darkfield microscope and demonstrated absence of large spirochetes. From the 15 patients, Porphyromas gingivalis was detected in 10% of the periodontal samples and in only one peri-implant sample. Prevotella intermedia was detected in 33% of the periodontal and in 30% of the peri-implant samples. Fusobacterium spp. had a prevalence of 58% in the periodontal samples and was recovered from 50% of the peri-implant samples. Actinobacillus actinomycetemcomitans was not detected in any dental or peri-implant sample. In 1 case, however, the organism was recovered from the internal surface of the suprastructure. Linear regression analysis showed a significant relationship between the frequency of micro-organisms in peri-implant samples of group S and in samples from the inner surface of the suprastructure. Furthermore, there was a significant correlation between the incidence of micro-organisms in dental samples and i) in peri-implant samples of group S and ii) in samples from the internal suprastructure surface. These findings indicate, that the microbial leakage through the gap between the suprastructure and the abutment plays an important role in the bacterial colonization of the internal part of screw retained crowns and bridges. The study furthermore confirms the impact of the dental microflora on the microbial colonization of implants. This factor appears to be more important than the mode of fixation of the suprastructure.
Adult↗
An in vitro evaluation of the strength of a 1-piece and 2-piece conical abutment joint in implant design.
The performance and maintenance of implant-supported prostheses are primarily dependent upon load transmission both at the bone-to-implant interface and within the implant-abutment-prosthesis complex. The design of the interface between components has been shown to have a profound influence on the stability of screw joints. In this in vitro evaluation, implants utilizing an internal conical joint have demonstrated a parity in resistance to bending moments at the fixture-abutment interface, when comparing a 1-piece abutment to a 2-piece abutment, which is tightened via a separate abutment screw, with mean plastic bending moments of 4176 N mm and 4049 N mm respectively. The very small values for coefficient of variance measured in both systems would confirm that whilst the size of data is small it is nonetheless a reliable indication of the relative strength of these conical joint designs.
Dental Abutments↗
The development of the ITI DENTAL IMPLANT SYSTEM. Part 1: A review of the literature.
In a short trip through more than twenty years, the development of the ITI DENTAL IMPLANT SYSTEM is described. The systematic unfolding and continuous advancement of the system, permanently supported and accompanied by scientific work in clinical and general practice, is outlined in short paragraphs. Some major milestones are emphasized and characterized.
Dental Abutments↗