Infraposition of anterior maxillary implant-supported single-tooth restorations in adolescent and adult patients-A prospective follow-up study up to 6 years.

BACKGROUND: In the maxillary incisor area infraposition of implant restorations can be an esthetic problem. PURPOSE: The aim was to analyze the prevalence of infraposition of single-tooth implant restorations in the anterior maxilla in adolescent and adult patients. MATERIAL AND METHODS: The study comprised of 31 patients, 18 women and 13 men, with 39 restorations and with a mean and median age of 23.8 and 18.8 years, range 17.8 to 52.8 years, at the time of implant crown connection. The mean and median time in function for the restorations was 4.5 and 4.3 years respectively with a range of 3.3 to 6.6 years. RESULTS: Twenty restorations 51%, showed no signs of infraposition. A slight infraposition (<0.5 mm) was seen in 36% of the restorations. Only in one patient, the observed infraposition of the implant crown was more than 1 mm. We found no significant difference of the observed level of vertical infraposition, Score A (0 mm) and Score B (<0.5 mm), in subjects where the restoration was placed before the age of 20 years compared to the older patients. There were no significant differences in changes of the vertical infraposition when comparing different parameters such as age, gender, jaw relation (Angle-classes I-III), overbite/overjet, occlusal contact on the implant crown, bone augmentation before or at implant installation or if orthodontic treatment of the neighboring teeth had been made before or after the implant installation. CONCLUSIONS: In the present study, there was a significant yet low correlation between the observed vertical infraposition of the single-tooth implant restoration and the subject's evaluation of the esthetics of the restoration (VAS). Fifty-one percent of the implant-supported crowns, showed no signs of vertical infraposition. A slight infraposition (< 0.5 mm) was however seen in 36% of the restorations. Only one crown showed a vertical infraposition of more than 1 mm.

One-piece internal zirconia abutments for single-tooth restorations on narrow and regular diameter implants: A 5-year prospective follow-up study.

BACKGROUND: Studies have reported an increased risk for fractures of zirconia abutments compared with titanium abutments. PURPOSE: The aim of this study was to evaluate single-tooth implant restorations with one-piece yttria-stabilized internal zirconia abutments on narrow and regular diameter implants up to 6 years after insertion. MATERIAL AND METHODS: This study comprises 52 consecutively treated patients, with a median age of 19 years. In total, 59 narrow (3.3 mm) and 10 regular (4.1 mm) diameter implants were installed. Sixty-five all-ceramic crowns were cemented on implant-supported one-piece internal zirconia abutments and 4 restorations were screw-retained. RESULTS: Thirty-five patients with 48 implant restorations participated in the final examination and another 14 patients with 16 implant restorations were possible to reach and could be interviewed. The implant survival was 100% but the survival rate for the implant-supported ceramic restorations was lower, 87.5%. Three crowns (4.7%) were remade for different reasons. Five restorations (7.8%) were remade due to fracture of the internal one-piece zirconia abutment. Four of these fractures occurred in 3.3 mm implant abutments. CONCLUSIONS: Narrow diameter implants offer an opportunity to restore small single-tooth edentulous gaps. For esthetical reasons the choice of an abutment in zirconia can be favorable, but at least with the used implant system, there seems to be an increased risk for fracture. Most patients were very satisfied with the esthetics and function of their implant restorations.

Four-Millimeter-Long Posterior-Mandible Implants: 5-Year Outcomes of a Prospective Multicenter Study.

BACKGROUND: There is lack of evidence on long-term success of short dental implants in reduced alveolar bone. PURPOSE: In this prospective 5-year study, survival and marginal bone loss of 4-mm implants, which supported fixed dental prostheses (FDPs) in severely resorbed posterior mandibles, were evaluated. MATERIAL AND METHODS: In 28 patients, evaluation of 86 osseointegrated 4-mm-long implants, which supported a 3- or a 4-unit FDP by crown splinting without the use of pontics or cantilevers, was performed over a 5-year period. RESULTS: Three subjects dropped out for non-study reasons: one subject had her three implants removed after 1 year and two subjects died (six implants). Five implants in three subjects were lost between 3 and 5 years. Twenty-four subjects and 71 implants were active at the 5-year follow-up (92.2% survival). After 1 year, significant (p < .001) mean (standard error of the mean [SEM]) 0.44-mm (0.05) marginal bone loss occurred. At 2, 3, and 5 years, mean (SEM) bone loss of 0.57 mm (0.06), 0.55 mm (0.07), and 0.53 mm (0.08) occurred, respectively (no significant change after 1 year). At 5 years, average plaque levels were 13.3%; 69% of the implants were plaque free. On average, mucosal bleeding occurred at 8.1% of the implants. During 5 years, two subjects experienced uncomplicated bridge loosening. No other complications occurred during the study. CONCLUSION: Four-millimeter implants can support FDPs in severely resorbed posterior mandibles for 5 years with healthy peri-implant conditions.

Evaluation of bone regeneration after three different lateral sinus elevation procedures using micro-computed tomography of retrieved experimental implants and surrounding bone: a clinical, prospective, and randomized study.

PURPOSE: To compare three different lateral sinus elevation procedures concerning new bone formation by using micro-computed tomography (micro-CT) of retrieved implants. MATERIALS AND METHODS: Twenty-four consecutive partially dentate patients with a mean age of 64 years were included in the study and provided with 30 sinus elevation procedures. Three procedures for lateral sinus elevation were used: lateral sinus elevation with replacement of bone window and without bone graft (BW), lateral sinus elevation and covering osteotomy site with a collagen membrane and without bone graft (CM), and lateral sinus elevation with autogenous bone graft (ABG). Experimental implants were retrieved after 7 months of healing and analyzed by micro-CT. RESULTS: One implant was found not to be integrated at the time of implant retrieval. This implant belonged to group CM and was excluded when calculating bone-to-implant contact (BIC) and intrasinus bone levels. The integrity of the lateral sinus bony wall was determined at the time of implant removal. In group ABG, all lateral sinus walls were ossified. In group BW, one lateral sinus wall was not completely ossified and in group CM, two lateral sinus walls. There were no statistical differences in %BIC between the groups: 93.5% (BW), 92.0% (CM) and 93.5% (ABG). Additionally, no statistical differences were found in apical intrasinus bone levels between the groups. When surfaces were compared within the same implant, a statistical difference was found between the apicobuccal distance and the apicolingual distance. The mean apicobuccal distances/apicolingual distances were 0.6 mm/1.2 mm for the BW group, 0.5 mm/0.8 mm for the CM group, and 0.6 mm/0.8 mm for the ABG group (P = .003). CONCLUSIONS: All three procedures were statistically equal when new bone formation was compared. Most of the examined implants' apices were not covered with bone at the time of retrieval.

Flapless, CBCT-guided osteotome sinus floor elevation with simultaneous implant installation. I: radiographic examination and surgical technique. A prospective 1-year follow-up.

BACKGROUND: Survival rates of implants placed in transalveolar sinus floor augmentation sites are comparable with those placed in non-augmented sites. Flapless implant surgery can minimize postoperative morbidity, alveolar bone resorption and crestal bone loss. The use of cone beam computerized tomography (CBCT) provides 3D presentations with reduced dose exposure. OBJECTIVES: To evaluate a flapless, CBCT-guided transalveolar sinus floor elevation technique with simultaneous implant installation. MATERIAL AND METHODS: Fourteen consecutive patients in need of maxillary sinus floor augmentation were enrolled in this study. Preoperative CBCT with a titanium screwpost as an indicator at the intended implant position was used to visually guide the flapless surgical procedure. Twenty one implants all with a length of 10 mm and a diameter of 4.1 and 4.8 mm were inserted and followed clinically and with CBCT for 3, 6 and 12 months postoperatively. Intraoral radiographs were taken for comparison. All patients were provided with permanent prosthetic constructions 8-12 weeks after implant surgery. RESULTS: Ten (47.6%) implants were inserted in residual bone of 2.6-4.9 mm and 11 (52.3%) implants were inserted in residual bone of 5-8.9 mm. No implants were lost after surgery and follow-up. There was no marginal bone loss during the follow-up verified by CBCT. The implants penetrated on average 4.4 mm (SD 2.1 mm) into the sinus cavity and the mean bone gain was 3 mm (SD 2.1 mm). CONCLUSION: Flapless transalveolar sinus lift procedures visually guided by preoperative CBCT can successfully be used to enable placement, successful healing and loading of one to three implants in residual bone height of 2.6-8.9 mm. There was no marginal bone loss during the 3-12 months follow-up.

Bone regeneration using a hollow hydroxyapatite space-maintaining device for maxillary sinus floor augmentation--a clinical pilot study.

BACKGROUND: The mere lifting of the maxillary sinus membrane by implants protruding into the sinus cavity allows the establishment of a void space for blood clot and new bone formation. PURPOSE: To evaluate bone formation by using a spherical, hollow, and perforated hydroxyapatite space-maintaining device (HSMD) in a two-stage sinus lift procedure where residual alveolar bone height was ≤2 mm. MATERIAL AND METHODS: Spherical, hollow, and perforated HSMDs with a diameter of 12 mm were manufactured for this pilot study. Three patients with a residual bone height of 1-2 mm, as verified clinically and radiographically, and in need of a sinus augmentation procedure prior to implant installation were selected for the study. The HSMD and bone formation was evaluated by cone beam computerized tomography (CBCT) 6 months after augmentation procedure. Implants were installed 6 to 9 months after augmentation. The implant sites were prepared by a trephine drill to obtain a specimen of HSMD and bone for histological evaluation. After implant installation, the condition of the sinus membrane adjacent to the HSMD was evaluated endoscopically. After an additional 8 weeks, fixed partial prostheses were fabricated. RESULTS: Bone formation verified by CBCT was found around and inside the device in all three patients after 6 months. Despite the fact that residual bone before augmentation was ≤2 mm, 12-mm-long implants with diameter of 4.8 mm could be inserted with preservation of an intact and healthy sinus membrane verified endoscopically. Bone formation inside HSMDs was noted histologically in two out of three HSMDs. Implants were stable and without any marginal bone loss after 1 year of prosthetic loading. CONCLUSION: A spherical, hollow, and perforated HSMD used in sinus lift procedures can produce a void space for blood clot and new bone formation and subsequent implant installation.

Four-millimeter implants supporting fixed partial dental prostheses in the severely resorbed posterior mandible: two-year results.

BACKGROUND: Reduced alveolar bone volume complicates implant dentistry. PURPOSE: In this prospective multicenter study, a new, 4-mm long Straumann SLActive implant (Ø 4.1 mm) supporting a fixed dental prosthesis (FDP) in the severely resorbed posterior mandible was evaluated for two years. MATERIAL AND METHODS: Thirty-two patients (11 men, 21 women; mean age 64.1 years) participated. Ten to 12 weeks after single-stage surgery, a screw-retained FDP was attached to three or four 4-mm implants. RESULTS AND DISCUSSION: One hundred implants were inserted. Three failed at surgery and four were lost before loading. Twenty-eight patients received FDPs (93 implants). Two patients were discontinued because of secondary exclusion criteria; therefore, 26 patients were followed up from baseline (BL). After 1 year, one patient insisted on removal of all implants and one patient died because of nonstudy-related complications. Twenty-four patients (87 implants) were eligible for examination 2 years post-loading. All implants were found to be stable [survival rate 95.7% (confidence interval, CI 88.8-98.3) after 1 year and 92.3% (CI 84.5-96.2) after 2 years]. The mean change from BL to 12 months was - 0.43 mm (CI 0.31-0.59; p < .001) and from 12 to 24 months - 0.11 mm (CI -0.01-0.23; p = .056). The survival rate is only slightly lower than in similar studies on 6 to 8.5 mm implants. This may be related to high initial stability and effective use of the residual bone volume with high primary bone-to-implant contact in dense bone structures. The surgical handling of the tested implant was found to be similar to that of implants of common length. However, the preparation procedure must be done with great care to avoid overdrilling. Careful planning and design of the prosthetic construction is mandatory to prevent unfavorable occlusion and avoid harmful shear forces. CONCLUSION: This study showed that 4 mm implants can support an FDP in severely resorbed posterior mandibles for at least 2 years and with healthy peri-implant conditions.

Frontal bone and modified zygomatic implants for retention of a nasal prosthesis: Surgical planning using a three-dimensional computer software program.

Implants integrated into bone have revolutionised the retention of total nasal prostheses. However, it may be difficult to identify available sites for placement of the implant after excision. In addition, it is ideal to minimise wide bony exposure after radiotherapy to avoid compromising the blood supply. In this paper we describe a technique for accurate placement of frontal bone and customised zygomatic implants using a computer-designed and fabricated surgical guide with a minimal access flap.

Need for a new care model--getting to grips with collaborative home care.

In this paper we discuss the fact that more and more patients are treated in their homes by a set of organizations, sometimes with different ownership, and how this fact places new and severe demands on health care and home service staff to communicate and collaborate. We point to the need for managers in different organizations to agree on ways of communicating and collaborating on the operational level and how this aspect needs to be considered during procurement of home care services. Most importantly, by reasoning around a set of problematic areas, we derive a set of related problems and suggest solutions for dealing with them. The solutions are a mix of organizational/administrative measures and IT support for communication and coordination.

Maxillary sinus floor augmentation and simultaneous implant placement using locally harvested autogenous bone chips and bone debris: a prospective clinical study.

PURPOSE: The aim of this study was to prospectively evaluate the status of implants, marginal bone loss, and outcome of maxillary sinus floor augmentation in patients undergoing maxillary sinus lift and simultaneous implant placement with the use of bone grafts harvested adjacent to the actual surgical site. MATERIALS AND METHODS: Patients in need of maxillary sinus floor augmentation to enable implant placement were enrolled in 2 different groups. In group A, a "bone trap" was used to harvest bone debris during implant preparation with additional bone collected by further drilling adjacent to the implant sites. In group B, a "bone scraper" was used to harvest cortical bone chips from the zygomatic buttress and from the lateral sinus wall before opening of a bony window. All patients were provided a fixed partial denture after a healing period of 3 to 6 months. A total of 61 patients with 81 Straumann implants (Institut Straumann AG, Basel, Switzerland) were assessed, with 17 patients (20 implants) in group A and 44 patients (61 implants) in group B. RESULTS: One implant was lost (in group B) before loading. The survival rate after a follow-up of 12 to 60 months was 98.8%. There was no significant difference in marginal bone loss on the mesial and distal sides of the implant when baseline to 1-year registration was compared with baseline to final registration. During the same time, graft height decreased significantly on the distal apical side of the implants. CONCLUSIONS: Bone grafts can be locally harvested at the site of the maxillary sinus augmentation procedure to enable placement, successful healing, and loading of 1 to 3 implants.

The development of a Swedish National Information Structure.

Sweden has as part of its national eHealth strategy decided to develop a generic National Information Structure. It is based on three models: The Generic Process, Concepts and Information model. The models are intended to be specialised for various forms of care including social and community care. The importance of interacting models developed in an iterative approach with user involvement is emphasised.

Short-term clinical results of Nobel Direct implants: a retrospective multicentre analysis.

PURPOSE: The present retrospective clinical study was undertaken to evaluate the survival rate and marginal bone conditions around Nobel Direct one-piece implants. The purpose was also to compare the results with when these implants are used for immediate/early loading with implants allowed to heal before loading. MATERIAL AND METHODS: Forty-three consecutive patients previously treated with 117 Nobel Direct implants at four different centres were evaluated. The implants had been used in both jaws for treatment after loss of single and multiple teeth. Immediate/early loading (within 2 weeks) with a provisional crown/bridge was applied to 95 implants, while 22 implants healed unloaded for 6 weeks to 6 months before loading. Calculations of marginal bone loss were performed in radiographs taken at placement and after an average of 10.2 months (range 1-18 months) of loading. RESULTS: Six (5.1%) of the 117 implants were removed during the follow up. All failed implants belonged to the immediate/early loading group giving a failure rate of 6.3% for this group and 0% for two-stage implants. The failure rate was higher for flapless (7.9%) than for flap surgery (0%). The marginal bone loss was -2.4 mm (SD 1.5) for all implants, while 37.6% showed more than 3 mm of loss during the follow up. Bone loss increased with time of follow up. Implants subjected to immediate/early loading showed more bone loss than two-stage implants: -2.6 mm (SD 1.5) vs. -1.6 mm (SD 1.1). Moreover, 41.3% of immediately loaded and 22.7% of two-stage implants presented with more than 3 mm of bone loss. CONCLUSIONS: This short-term retrospective analysis showed a poor clinical outcome of Nobel Direct implants. Extensive marginal bone loss (>3 mm) was found around more than 1/3 of the implants evaluated. Less resorption and no failures were experienced when implants were allowed to heal from 6 weeks to 6 months before occlusal loading. Within the limitations of the present study design, data indicate that immediate loading, the use of this implant for multi-unit constructions and flapless surgery are risk factors for failure of Nobel Direct implants.

Stability of the screw joints in patients with implant-supported fixed prostheses in edentulous jaws: a 1-year follow-up study.

PURPOSE: The purpose of this follow-up study was to evaluate the stability of the screw joint in edentulous patients 1 year after treatment with implant-supported fixed prostheses (Brånemark system). MATERIALS AND METHODS: A total of 20 patients were included, 10 treated in the maxilla and 10 in the mandible. The fixed prostheses were removed approximately 1 year after insertion, and the stability of the screw joints was evaluated using a rating scale based upon the CDA quality evaluation criteria of dental care. RESULTS: All implant-supported fixed prostheses were recorded as stable before the prosthetic screws (gold screws) were unscrewed. "Unacceptable loosening" was observed in 4% of the prosthetic screws and in 29% of the abutment screws. CONCLUSION: In this study, only a few of the prosthetic screws showed unacceptable loosening after 1 year of function. The clinical relevance of the observed high occurrence of loose abutment screws could be questioned, as all fixed prostheses were initially recorded as stable.

Peri-implant mucosal level in patients treated with implant-supported fixed prostheses: a 1-year follow-up study.

PURPOSE: The purpose of this follow-up study was to quantify the change in the peri-implant mucosal level after treatment of edentulous patients with fixed prostheses on osseointegrated endosseous implants. MATERIALS AND METHODS: Twenty patients were included in the study: 10 were treated in the maxilla, and 10 were treated in the mandible. Both groups had fixed prostheses on osseointegrated Brånemark implants. Peri-implant mucosal level was measured with a calibrated probe after removal of the prostheses at the 1-year follow-up. These measurements were compared to those made on the original master casts. RESULTS: A larger mean retraction (-) was observed in the mandible (-1.6 mm) compared to the maxilla (-0.8 mm), but there was great variation. The individual values varied from -4.5 to +1.0 mm in the mandible and from -6.0 to +6.0 mm in the maxilla. CONCLUSION: Peri-implant soft tissue recession occurs during the first year in edentulous jaws after treatment with implant-supported fixed prostheses and more so in the maxilla than the mandible.

Implant-supported fixed partial prostheses: a retrospective study.

PURPOSE: The purpose of this retrospective study was to present treatment outcome and patient reactions to rehabilitation with implant-supported fixed partial prostheses. MATERIALS AND METHODS: Eighty-three patients were consecutively treated with implant-supported fixed partial prostheses (Brånemark system) from 1986 to 1995. Seventy-six of these 83 patients were examined (66 maxillary and 31 mandibular prostheses). The mean observation time was 53.9 months. In total, 285 implants were placed. Eleven implants were lost before loading. The first 41 prostheses were removed and the implants examined regarding the criteria for "success" and tightness of the screw joints. Only one implant had lost integration. RESULTS: The survival rate before and after loading was 96%, which included implants placed in augmented bone. All prostheses were stable at the time of examination. In prostheses with cantilevers (98 implants), 12% of the gold screws and 17% of the abutment screws showed a "not acceptable" loosening, compared to none in the prostheses without cantilevers (17 implants). The difference was not statistically significant. The mean marginal bone loss was 0.4 mm for the first year after prosthesis insertion and less than 0.1 mm per year in the following years. The most frequent prosthesis design was one pontic supported by two implants. Prostheses made in gold acrylic and titanium acrylic had more complications and showed a higher need for repair than metal-ceramic restorations. Patients reacted very positively to the esthetic results and comfort with eating, and were overall satisfied with their prostheses. CONCLUSION: Implant-supported fixed partial prostheses seem to have a very good prognosis and are well-accepted by patients.

A remote auscultation tool for advanced home health-care.

We have developed an Internet-based tool for remote realtime auscultation. The device was based on a commercially available electronic stethoscope and a PC which digitized and transmitted the signals. A voice and video channel were also available. The remote auscultation tool was evaluated between two sites in Sweden separated by a distance of 500 km. A doctor at one of the sites performed cardiac and pulmonary auscultations on patients located at the other site. Four test patients were assisted by a nurse operating the electronic stethoscope. The auscultation sessions were performed with and without video support to assess the importance of visual contact between doctor and patient. Twenty sessions were conducted (excluding technical testing to solve problems with the equipment). Audio quality was sufficient, as judged subjectively by the doctors concerned. Video support improved the doctor s confidence that the stethoscope was being operated properly and greatly simplified the interaction. Moreover, it improved all participants subjective impression of the virtual meeting. Our work demonstrates the feasibility of performing remote auscultation sessions over the Internet.