Posterior implants for distal extension removable prostheses: a retrospective study

Common complaints associated with the Kennedy Class I (bilateral free end) and Class II (unilateral free end) removable partial denture situations are lack of stability, minimal retention, and unesthetic retentive clasping. Some of the same complaints have been reported for implant overdentures with only anterior implants. Starting in 1995, 10 of these patients were treated at the University of Washington with posterior osseointegrated implants to provide stability and/or retention of the removable prostheses, eliminating the need for clasps when possible. This article describes implant alternatives and prosthesis designs and presents a follow-up clinical evaluation of at least 1 year consisting of patient satisfaction, radiographic examination, and soft tissue health. Two groups were evaluated. Group 1 included patients whose implants were used as vertical stops for mandibular distal extension prostheses. Care was taken to ensure that the implants were not loaded laterally by creating a single-point contact at the center of a modified healing abutment. In these cases, sufficient retention was available from the anterior teeth and/or implant abutments. Group 2 included patients whose implants required retention because of lack of adequate tooth abutments. In those cases, a resilient type of attachment was used, which allowed for a small divergence from the path of insertion. Results indicated consistent increased satisfaction in all patients, minimal component wear, no radiographic evidence of excessive bone loss, and stable peri-implant soft tissues.     

Early bone formation around immediately loaded FBR-coated implants after 8, 10 and 12 weeks: a human histologic evaluation of three retrieved implants

The surface characteristics of dental implants play an important role in the osseointegration process. Over the years implant surfaces have been subjected to different treatments, including turning, plasma spraying, coating, sand blasting, acid etching, and anodization. FBR coating is a fully resorbable calcium phosphate (CaP) coating made of brushite, obtained by electrochemical deposition on titanium plasma-sprayed (TPS) implants; this bioactive layer may be totally resorbable in 6-12 weeks and once the FBR coating has been resorbed, the newly formed bone is in contact with the roughness of the TPS surface. Human biopsy of immediately-loaded implants is certainly the most definitive means of determining the occurrence of osseointegration. In this case series the histologic and histomorphometric features of the bone-implant interface are analyzed and discussed in 3 immediately restored implants, retrieved from human subjects at 8, 10 and 12 weeks, respectively. All 3 implants were osseointegrated, with a bone to implant contact (BIC) ranging from 54.4% to 70.1%. The FBR coating was resorbed and replaced by new bone. Osteoconduction was especially noticeable between the implant threads, where the pristine bone was removed during implant bed preparation. The results suggest that the resorption window of 6-12 weeks for the CaP coating seems to be confirmed at least in the human mandible, and that immediately loaded FBR-coated implants placed in the posterior mandible can achieve osseointegration within 6-12 weeks of loading.     

Outcomes of fixed prostheses supported by immediately loaded endosseous implants

PURPOSE: The aim of this article was to evaluate the survival and success of Straumann implants after immediate loading. A new method for fabricating effective definitive prostheses to immediately load implants in edentulous patients was presented. MATERIALS AND METHODS: Nine patients received 4 implants each, and resin-metal prostheses were installed less than 48 hours after implant placement. Mobility was evaluated immediately after the surgical procedures and 3 months subsequently using the Periotest. Clinical evaluation of soft peri-implant tissues was conducted monthly after the sutures were removed, and radiographs were obtained 6, 12, and 24 months after the surgery. RESULTS: The Periotest revealed statistical values that were stable, with no mobility. No signs of inflammation and/or bleeding were observed. The radiographs did not reveal any continuous areas of radiolucency beyond the first thread of the 36 implants after 24 months. None of them failed, and the success rate was 100%. DISCUSSION: It is possible to submit implants to immediate load without jeopardizing osseointegration if parameters are met, such as suitable bone quality and quantity, lack of unfavorable systemic and psychologic factors, lack of parafunctional habits, strict maintenance of prosthetic requirements, minimization of micromotion, and use of an appropriate surgical protocol. CONCLUSION: Under immediate load, osseointegration of implants is possible, and the method presented for the fabrication of resin-metal prostheses has been reliable and predictable.     

Complications after treatment with implant-supported fixed prostheses: a retrospective study

PURPOSE: The aim was to retrospectively evaluate the frequencies of different complications, as well as the number of visits to dentists because of such complications, after treatment with implant-supported fixed prostheses. MATERIALS AND METHODS: The study group comprised 75 patients who had been treated with implant-supported fixed prostheses 3 years earlier. All case records were scrutinized, and notes of complications in association with implants and superstructures were registered. RESULTS: The most common intervention made was occlusal adjustment/selective grinding of the prostheses. Complications in association with both implants and superstructures were fairly common. The most frequent complication was fractures of the acrylic resin matrix, including artificial acrylic resin teeth. Consultations because of periimplant mucosal inflammation were much more common among women compared to men, while complications that could be attributed to heavy loading tended to be more common in men. CONCLUSION: Complications with both implants and superstructures are fairly common after treatment with implant-supported fixed prostheses. Regular follow-ups to maintain optimal function in these patients are thus mandatory.     

Multicenter retrospective study of cement-retained implant-supported anterior partial prostheses: success and restoration evaluation

PURPOSE: The aim of this multicenter study was to evaluate implant success and restorative complications of cement-retained implant-supported anterior partial prostheses in Jordan. MATERIALS AND METHODS: A retrospective study of all implants with a minimum of 1-year follow-up were used to support fixed, cement-retained restorations from April 2000 until March 2007. The cement-retained implants were loaded with either single- or multiple-tooth replacements. The Fisher exact test was performed to test the presence of any statistically significant difference in success concerning gender or arch of placement. RESULTS: Eighty-seven implants were placed in the anterior region of the mandible or maxilla in 49 patients at multiple clinical practices in Jordan. The age of the patients ranged from 17 to 85 years. Eighteen implants were placed in the mandible and 69 in the maxilla. Three maxillary implants in 2 male patients had 3-mm horizontal bone loss. Those 3 implants are still functioning and were considered surviving implants but not successful implants. Therefore, the implant cumulative survival rate for both arches and genders was 100%. The implant cumulative success rate was 95.78%. Three crowns (maxillary) were dislodged. No significant differences were revealed regarding gender or arch of placement (P > .05). CONCLUSIONS: Cement-retained implants exhibited high survival and success rates among a Jordanian population.     

Early functional loading of unsplinted roughened surface implants with mandibular overdentures 2 weeks after surgery

Background: Before early functional loading of unsplinted implants with mandibular overdentures can become widespread, more clinical studies are needed to investigate the success of the approach. Purpose: To evaluate the success rates of two types of roughened titanium surface implants with early 2‐week functional loading of paired mandibular interforaminal implants with overdentures. Materials and Methods: Random allocation divided 24 strictly selected edentulous participants into two groups, with each group to receive a different implant system (ITI Dental Implant System, Straumann AG, Waldenburg, Switzerland; or Southern Implant System, Southern Implants, Irene, South Africa). Two implants were placed in the anterior mandible of all participants using one‐stage standardized surgical procedures. Previously constructed conventional mandibular dentures (opposing maxillary complete dentures) were temporarily relined and worn by the participants for the first 2 weeks; participants used a soft diet. Two weeks after implant surgery and following some mucosal healing, the mandibular dentures had the tissue conditioner removed and the appropriate matrices included for an unsplinted prosthodontic design. Results: No implant from either group was lost. Resonance frequency analysis (RFA) indicated higher primary stability at surgery for the Southern group than for the ITI group, with a statistically significant difference between the groups throughout the study period. The drop in RF values between surgery and 6 weeks was significant and was greater for the Southern group. RFA also indicated stabilized osseointegration between 6 to 12 and 12 to 52 weeks, with no participant showing any decrease in those values over time. Participants with type 3 bone showed a significant improvement in RF values between 12 and 52 weeks, eventually matching those of participants with type 2 bone. There were no significant differences in marginal bone loss, periimplant parameters, or prosthodontic maintenance between the groups over the study period. Conclusions: Using only strict patient selection criteria, 1‐year follow‐up data indicate that early functional loading of ITI and Southern implants with mandibular two‐implant overdentures is possible as early as 2 weeks after implant surgery.     

Prospective clinical evaluation of dental implants with sand-blasted, large-grit, acid-etched surfaces loaded 6 weeks after surgery.

Twenty implants with sand-blasted, large-grit, acid-etched (SLA) surfaces (ITI Dental System) were followed up for a period of 12 months, during which the following clinical criteria were evaluated: (a) absence of persistent clinical symptoms (pain, strange sensations, or paresthesia) after the placement of implants; (b) absence of recurring peri-implant inflammation or suppuration; (c) absence of increasing mobility, tested with Periotest; and (d) absence of bone loss or radiolucency around the implants. After 12 months of follow-up, all the loaded implants, after 6 weeks of placement, were approved under all the aforementioned criteria. During the analysis of the increasing mobility, tested with Periotest, and grouping these implants according to the site of implantation (mandible or maxilla), it was possible to observe that the implants presented the same increasing mobility.     

Multicenter retrospective analysis of 201 consecutively placed camlog dental implants

Camlog tube-in-tube implants were introduced several years ago. This multicenter retrospective analysis evaluated the success rate of Root-Line and Screw-Line tube-in-tube implants in daily use. A total of 201 implants were placed in 96 patients with different indications and implantation procedures. Implants were analyzed retrospectively after a functional loading period of 12 to 78 months. At the end of the observation period, all but 1 implant fulfilled the success criteria, resulting in an implant survival rate of 99.5%. Individual case analysis of implants in special indications, such as immediate loading, short implants, and tilted implants, did not indicate any increased risk of implant failure.     

A newly designed template device for use with the insertion of immediately loaded implants

This article describes a newly designed surgical template that was used to facilitate dental implant placement. The implants were planned to function by loading them immediately. A case report describing the device and the benefits of its use for a patient with an edentulous mandible is presented. Four implants were placed in the anterior region of the mandible to support an immediately fixed prosthesis. Clinical and radiographic analyses were conducted postoperatively to evaluate bone loss and peri-implant soft-tissue healing. The salutary results demonstrated the positive value of this therapeutic approach and presented the advantages of shorter treatment times, fewer patient visits, lower costs, and elimination of secondary surgical procedures.     

Multicenter retrospective analysis of wide-neck dental implants for single molar replacement

PURPOSE: To evaluate the predictability of Straumann wide-neck dental implants (6.5-mm prosthetic neck with a 4.8-mm endosseous sandblasted, large-grit, acid-etched-surface body) used for molar replacement. MATERIALS AND METHODS: Four hundred ninety-nine single-tooth implants were restored in molar sites in 410 patients (mean time of loading 23 months; range, 1 to 54 months) by 6 clinicians throughout the United States. Three hundred-fifty nine implants were placed in the mandible and 148 implants in the maxilla. RESULTS: The overall cumulative survival rate was 98.4% for all sites (8 failures). Survival rates of 99.2% for mandibular molars (3 failures) and 96.6% for maxillary molars (5 failures) were achieved. Survival rate of implants placed in conjunction with the bone-added osteotome procedure in the maxillary molars was 89%, with 5 of 45 procedures leading to failure. DISCUSSION: Minimal restorative problems were encountered. No cases of abutment loosening or fractures were observed for cemented restorations on solid abutments. CONCLUSION: The data suggest that the Straumann solid-screw, wide-neck implants can be a satisfactory choice for molar single-tooth replacement.     

A retrospective study of implant-retained auricular prostheses

PURPOSE: The purpose of this study was to retrospectively evaluate the clinical results of the implant-retained auricular prosthesis. MATERIALS AND METHODS: Data were collected from 46 patients who were treated between 1992 and 2004 with implant-retained auricular prostheses. A total of 156 implants and 1 plate (Epitec System) were placed in 46 patients, including 23 EO System implants, and 133 Br?nemark implants. The implant survival rate was 100%. Twenty patients with 53 implants were reexamined to evaluate the peri-implant soft tissue status. Two clinical peri-implant parameters were applied, skin probing depth and sulcus fluid flow rate. RESULTS: No adverse skin reactions were observed in 22 implants. Skin pockets were found in all of the 53 reexamined implants, which indicates the need for greater skin reduction. The mean skin probing depth and sulcus fluid flow rate were 2.1 +/- 0.9 mm and 1.8 +/- 1.3 mm, respectively, and a significant positive correlation was found between these 2 parameters. CONCLUSIONS: From these results, it can be concluded that the implant-retained auricular prosthesis promises long-term stability for patients with severe defects or total loss of the ear. Furthermore, sulcus fluid flow rate is a valuable parameter for the evaluation of peri-implant soft tissue.     

Biomechanical three-dimensional finite-element analysis of maxillary prostheses with implants. Design of number and position of implants for maxillary prostheses after hemimaxillectomy

The present study analyzed stress distributions in craniofacial structures around implant-supported maxillary prostheses. Using post-hemimaxillectomy computed tomography (CT) of a patient, the authors constructed a three-dimensional (3D) solid model using Digital Imaging and Communications in Medicine data (DICOM data) for maxillofacial and cranial bones. The effects of different prosthesis designs on stress distributions in craniofacial bones and osseous tissues around the implants were biomechanically investigated using 3D finite-element analysis. Maxillary prostheses were designed with 2 implants in the zygoma on the affected side and 2–3 implants in the maxillary alveolar bone on the unaffected side, without using a cantilever. Zygomatic implants provided suitable stress dispersal to the zygomatic and craniofacial bones on the affected side. This information is useful for designing maxillary prostheses.     

Zygomaticus implants for retention of nasal prostheses after rhinectomy

Malignant tumours of the nose occasionally require rhinectomy. Implant retained prostheses can give good aesthetic results. Predictable biomechanical retention of nasal prostheses can be achieved using osseointegrated implants and Br?nemark intra-oral and craniofacial implants have been used previously. Zygomaticus implants are traditionally used for dental rehabilitation of the partially edentulous maxilla with severe bone resorption. We describe two patients in whom zygomaticus implants have been used to aid salvage in prosthetic reconstruction of the nose.